[bugfix] rm duplication process dimension

2019-06-11 21:15:29 +08:00
205 changed files with 5119 additions and 7585 deletions
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,5 @@
 language: java
 os: linux
-dist: trusty
 addons:
  apt:
    sources:
--- a/9
+++ b/9
@@ -17,9 +17,9 @@ TEST_COMPILER_FLAGS = BASE_COMPILER_FLAGS + GMOCK_OVERRIDE_FLAGS + [
 yoga_cxx_library(
    name = "yoga",
    srcs = glob(["yoga/**/*.cpp"]),
+    header_namespace = "",
+    exported_headers = subdir_glob([("", "yoga/**/*.h")]),
    compiler_flags = LIBRARY_COMPILER_FLAGS,
-    public_include_directories = ["."],
-    raw_headers = glob(["yoga/**/*.h"]),
    soname = "libyogacore.$(ext)",
    tests = [":YogaTests"],
    visibility = ["PUBLIC"],
@@ -31,14 +31,13 @@ yoga_cxx_library(
 yoga_cxx_library(
    name = "yogaForDebug",
    srcs = glob(["yoga/**/*.cpp"]),
+    header_namespace = "",
+    exported_headers = subdir_glob([("", "yoga/**/*.h")]),
    compiler_flags = TEST_COMPILER_FLAGS,
-    public_include_directories = ["."],
-    raw_headers = glob(["yoga/**/*.h"]),
    soname = "libyogacore.$(ext)",
    tests = [":YogaTests"],
    visibility = ["PUBLIC"],
    deps = [
-        ":yoga",
        yoga_dep("lib/fb:ndklog"),
    ],
 )
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,9 +9,8 @@ cmake_minimum_required(VERSION 3.4.1)

 set(CMAKE_VERBOSE_MAKEFILE on)

-file(GLOB_RECURSE yogacore_SRC yoga/*.cpp)
+file(GLOB yogacore_SRC yoga/*.cpp)
 add_library(yogacore STATIC ${yogacore_SRC})

-target_include_directories(yogacore PUBLIC .)
 target_link_libraries(yogacore android log)
 set_target_properties(yogacore PROPERTIES CXX_STANDARD 11)
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -1,77 +1,3 @@
 # Code of Conduct

-## Our Pledge
-
-In the interest of fostering an open and welcoming environment, we as
-contributors and maintainers pledge to make participation in our project and
-our community a harassment-free experience for everyone, regardless of age, body
-size, disability, ethnicity, sex characteristics, gender identity and expression,
-level of experience, education, socio-economic status, nationality, personal
-appearance, race, religion, or sexual identity and orientation.
-
-## Our Standards
-
-Examples of behavior that contributes to creating a positive environment
-include:
-
-* Using welcoming and inclusive language
-* Being respectful of differing viewpoints and experiences
-* Gracefully accepting constructive criticism
-* Focusing on what is best for the community
-* Showing empathy towards other community members
-
-Examples of unacceptable behavior by participants include:
-
-* The use of sexualized language or imagery and unwelcome sexual attention or
-  advances
-* Trolling, insulting/derogatory comments, and personal or political attacks
-* Public or private harassment
-* Publishing others' private information, such as a physical or electronic
-  address, without explicit permission
-* Other conduct which could reasonably be considered inappropriate in a
-  professional setting
-
-## Our Responsibilities
-
-Project maintainers are responsible for clarifying the standards of acceptable
-behavior and are expected to take appropriate and fair corrective action in
-response to any instances of unacceptable behavior.
-
-Project maintainers have the right and responsibility to remove, edit, or
-reject comments, commits, code, wiki edits, issues, and other contributions
-that are not aligned to this Code of Conduct, or to ban temporarily or
-permanently any contributor for other behaviors that they deem inappropriate,
-threatening, offensive, or harmful.
-
-## Scope
-
-This Code of Conduct applies within all project spaces, and it also applies when
-an individual is representing the project or its community in public spaces.
-Examples of representing a project or community include using an official
-project e-mail address, posting via an official social media account, or acting
-as an appointed representative at an online or offline event. Representation of
-a project may be further defined and clarified by project maintainers.
-
-## Enforcement
-
-Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at <opensource-conduct@fb.com>. All
-complaints will be reviewed and investigated and will result in a response that
-is deemed necessary and appropriate to the circumstances. The project team is
-obligated to maintain confidentiality with regard to the reporter of an incident.
-Further details of specific enforcement policies may be posted separately.
-
-Project maintainers who do not follow or enforce the Code of Conduct in good
-faith may face temporary or permanent repercussions as determined by other
-members of the project's leadership.
-
-## Attribution
-
-This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
-available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
-
-[homepage]: https://www.contributor-covenant.org
-
-For answers to common questions about this code of conduct, see
-https://www.contributor-covenant.org/faq
-
+Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please [read the full text](https://code.fb.com/codeofconduct/) so that you can understand what actions will and will not be tolerated.
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # Yoga [![CocoaPods](https://img.shields.io/cocoapods/v/YogaKit.svg)](http://cocoapods.org/pods/YogaKit) [![npm](https://img.shields.io/npm/v/yoga-layout.svg)](https://www.npmjs.com/package/yoga-layout) [![bintray](https://img.shields.io/bintray/v/facebook/maven/com.facebook.yoga:yoga.svg)](https://bintray.com/facebook/maven/com.facebook.yoga%3Ayoga/_latestVersion) [![NuGet](https://img.shields.io/nuget/v/Facebook.Yoga.svg)](https://www.nuget.org/packages/Facebook.Yoga)

 ## Building
-Yoga builds with [buck](https://buckbuild.com). Make sure you install buck before contributing to Yoga. Yoga's main implementation is in C++, with bindings to supported languages and frameworks. When making changes to Yoga please ensure the changes are also propagated to these bindings when applicable.
+Yoga builds with [buck](https://buckbuild.com). Make sure you install buck before contributing to Yoga. Yoga's main implementation is in C, with bindings to supported languages and frameworks. When making changes to Yoga please ensure the changes are also propagated to these bindings when applicable.

 ## Testing
 For testing we rely on [gtest](https://github.com/google/googletest) as a submodule. After cloning Yoga run `git submodule init` followed by `git submodule update`.
--- a/ReactYoga.xcodeproj/project.pbxproj
+++ b/ReactYoga.xcodeproj/project.pbxproj
@@ -859,6 +859,9 @@
 		597633381F4E021D005BE8A4 /* RCTShadowView+Internal.h in Headers */ = {isa = PBXBuildFile; fileRef = 597633351F4E021D005BE8A4 /* RCTShadowView+Internal.h */; };
 		597633391F4E021D005BE8A4 /* RCTShadowView+Internal.h in Headers */ = {isa = PBXBuildFile; fileRef = 597633351F4E021D005BE8A4 /* RCTShadowView+Internal.h */; };
 		598FD1921F816A2A006C54CB /* RAMBundleRegistry.h in Copy Headers */ = {isa = PBXBuildFile; fileRef = C6D380181F71D75B00621378 /* RAMBundleRegistry.h */; };
+		598FD1951F817335006C54CB /* RCTModalManager.h in Headers */ = {isa = PBXBuildFile; fileRef = 91076A881F743AB00081B4FA /* RCTModalManager.h */; };
+		598FD1961F817335006C54CB /* RCTModalManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 91076A871F743AB00081B4FA /* RCTModalManager.m */; };
+		598FD1971F817336006C54CB /* RCTModalManager.h in Headers */ = {isa = PBXBuildFile; fileRef = 91076A881F743AB00081B4FA /* RCTModalManager.h */; };
 		599FAA361FB274980058CCF6 /* RCTSurface.h in Headers */ = {isa = PBXBuildFile; fileRef = 599FAA2A1FB274970058CCF6 /* RCTSurface.h */; };
 		599FAA371FB274980058CCF6 /* RCTSurface.h in Headers */ = {isa = PBXBuildFile; fileRef = 599FAA2A1FB274970058CCF6 /* RCTSurface.h */; };
 		599FAA381FB274980058CCF6 /* RCTSurface.mm in Sources */ = {isa = PBXBuildFile; fileRef = 599FAA2B1FB274970058CCF6 /* RCTSurface.mm */; };
@@ -996,6 +999,7 @@
 		8507BBBF21EDACC200AEAFCA /* JSCExecutorFactory.mm in Sources */ = {isa = PBXBuildFile; fileRef = 8507BBBC21EDACC200AEAFCA /* JSCExecutorFactory.mm */; };
 		8507BBC021EDACC200AEAFCA /* JSCExecutorFactory.h in Headers */ = {isa = PBXBuildFile; fileRef = 8507BBBD21EDACC200AEAFCA /* JSCExecutorFactory.h */; };
 		8507BBC121EDACC200AEAFCA /* JSCExecutorFactory.h in Headers */ = {isa = PBXBuildFile; fileRef = 8507BBBD21EDACC200AEAFCA /* JSCExecutorFactory.h */; };
+		916F9C2D1F743F57002E5920 /* RCTModalManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 91076A871F743AB00081B4FA /* RCTModalManager.m */; };
 		A2440AA21DF8D854006E7BFC /* RCTReloadCommand.h in Headers */ = {isa = PBXBuildFile; fileRef = A2440AA01DF8D854006E7BFC /* RCTReloadCommand.h */; };
 		A2440AA31DF8D854006E7BFC /* RCTReloadCommand.m in Sources */ = {isa = PBXBuildFile; fileRef = A2440AA11DF8D854006E7BFC /* RCTReloadCommand.m */; };
 		A2440AA41DF8D865006E7BFC /* RCTReloadCommand.h in Headers */ = {isa = PBXBuildFile; fileRef = A2440AA01DF8D854006E7BFC /* RCTReloadCommand.h */; };
@@ -2055,6 +2059,8 @@
 		83F15A171B7CC46900F10295 /* UIView+Private.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "UIView+Private.h"; sourceTree = "<group>"; };
 		8507BBBC21EDACC200AEAFCA /* JSCExecutorFactory.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = JSCExecutorFactory.mm; sourceTree = "<group>"; };
 		8507BBBD21EDACC200AEAFCA /* JSCExecutorFactory.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JSCExecutorFactory.h; sourceTree = "<group>"; };
+		91076A871F743AB00081B4FA /* RCTModalManager.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RCTModalManager.m; sourceTree = "<group>"; };
+		91076A881F743AB00081B4FA /* RCTModalManager.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RCTModalManager.h; sourceTree = "<group>"; };
 		A2440AA01DF8D854006E7BFC /* RCTReloadCommand.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTReloadCommand.h; sourceTree = "<group>"; };
 		A2440AA11DF8D854006E7BFC /* RCTReloadCommand.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTReloadCommand.m; sourceTree = "<group>"; };
 		AC70D2E81DE489E4002E6351 /* RCTJavaScriptLoader.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = RCTJavaScriptLoader.mm; sourceTree = "<group>"; };
@@ -2399,6 +2405,8 @@
 				83392EB21B6634E10013B15F /* RCTModalHostViewController.m */,
 				83A1FE8D1B62643A00BE0E65 /* RCTModalHostViewManager.h */,
 				83A1FE8E1B62643A00BE0E65 /* RCTModalHostViewManager.m */,
+				91076A881F743AB00081B4FA /* RCTModalManager.h */,
+				91076A871F743AB00081B4FA /* RCTModalManager.m */,
 				58114A121AAE854800E7D092 /* RCTPicker.h */,
 				58114A131AAE854800E7D092 /* RCTPicker.m */,
 				58114A141AAE854800E7D092 /* RCTPickerManager.h */,
@@ -3020,6 +3028,7 @@
 				3D7BFD301EA8E3FA008DFB7A /* RCTSRWebSocket.h in Headers */,
 				59EDBCA81FDF4E0C003573DE /* RCTScrollableProtocol.h in Headers */,
 				3D302F6C1DF828F800D6DDAE /* RCTAnimationType.h in Headers */,
+				598FD1951F817335006C54CB /* RCTModalManager.h in Headers */,
 				657734871EE834E000A0E9EA /* RCTInspectorDevServerHelper.h in Headers */,
 				3D302F6D1DF828F800D6DDAE /* RCTAutoInsetsProtocol.h in Headers */,
 				3D302F6E1DF828F800D6DDAE /* RCTBorderDrawing.h in Headers */,
@@ -3180,6 +3189,7 @@
 				3D80DA2D1DF820620028D040 /* RCTFrameUpdate.h in Headers */,
 				3D80DA2E1DF820620028D040 /* RCTImageSource.h in Headers */,
 				3D80DA2F1DF820620028D040 /* RCTInvalidating.h in Headers */,
+				598FD1971F817336006C54CB /* RCTModalManager.h in Headers */,
 				599FAA3A1FB274980058CCF6 /* RCTSurfaceDelegate.h in Headers */,
 				3D80DA301DF820620028D040 /* RCTJavaScriptExecutor.h in Headers */,
 				3DCE53281FEAB23100613583 /* RCTDatePicker.h in Headers */,
@@ -3992,6 +4002,7 @@
 				2D3B5EA81D9B08D300451313 /* RCTUtils.m in Sources */,
 				599FAA451FB274980058CCF6 /* RCTSurfaceRootView.mm in Sources */,
 				2D3B5EC81D9B095800451313 /* RCTActivityIndicatorViewManager.m in Sources */,
+				598FD1961F817335006C54CB /* RCTModalManager.m in Sources */,
 				3DCD185D1DF978E7007FE5A1 /* RCTReloadCommand.m in Sources */,
 				130443DB1E401ADD00D93A67 /* RCTConvert+Transform.m in Sources */,
 				3D0B84301EC0B51200B2BD8E /* RCTTVNavigationEventEmitter.m in Sources */,
@@ -4243,6 +4254,7 @@
 				391E86A41C623EC800009732 /* RCTTouchEvent.m in Sources */,
 				1450FF861BCFF28A00208362 /* RCTProfile.m in Sources */,
 				13AB90C11B6FA36700713B4F /* RCTComponentData.m in Sources */,
+				916F9C2D1F743F57002E5920 /* RCTModalManager.m in Sources */,
 				F1EFDA50201F661000EE6E4C /* RCTUIUtils.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
--- a/YogaKit/Source/YGLayout.m
+++ b/YogaKit/Source/YGLayout.m
@@ -180,7 +180,7 @@ static YGConfigRef globalConfig;
  // the measure function. Since we already know that this is a leaf,
  // this *should* be fine. Forgive me Hack Gods.
  const YGNodeRef node = self.node;
-  if (!YGNodeHasMeasureFunc(node)) {
+  if (YGNodeHasMeasureFunc(node)) {
    YGNodeSetMeasureFunc(node, YGMeasureView);
  }

--- a/gradle.properties
+++ b/gradle.properties
@@ -9,7 +9,7 @@

 org.gradle.jvmargs=-Xmx1536M

-VERSION_NAME=1.16.0
+VERSION_NAME=1.14.0-SNAPSHOT
 POM_URL=https://github.com/facebook/yoga
 POM_SCM_URL=https://github.com/facebook/yoga.git
 POM_SCM_CONNECTION=scm:git:https://github.com/facebook/yoga.git
--- a/java/BUCK
+++ b/java/BUCK
@@ -50,7 +50,6 @@ yoga_java_library(
    visibility = ["PUBLIC"],
    deps = [
        ":jni",
-        FBJNI_JAVA_TARGET,
        INFER_ANNOTATIONS_TARGET,
        JSR_305_TARGET,
        PROGRUARD_ANNOTATIONS_TARGET,
--- a/java/build.gradle
+++ b/java/build.gradle
@@ -62,7 +62,6 @@ dependencies {
    compileOnly project(':yoga:proguard-annotations')
    implementation 'com.facebook.soloader:soloader:0.5.1'
    testImplementation 'junit:junit:4.12'
-    testCompile project(':testutil')
 }

 task sourcesJar(type: Jar) {
--- a/java/com/facebook/yoga/LayoutPassReason.java
+++ b/java/com/facebook/yoga/LayoutPassReason.java
@@ -1,42 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-package com.facebook.yoga;
-
-public enum LayoutPassReason {
-  INITIAL(0),
-  ABS_LAYOUT(1),
-  STRETCH(2),
-  MULTILINE_STRETCH(3),
-  FLEX_LAYOUT(4),
-  MEASURE(5),
-  ABS_MEASURE(6),
-  FLEX_MEASURE(7);
-
-  private final int mIntValue;
-
-  LayoutPassReason(int intValue) {
-    mIntValue = intValue;
-  }
-
-  public int intValue() {
-    return mIntValue;
-  }
-
-  public static LayoutPassReason fromInt(int value) {
-    switch (value) {
-      case 0: return INITIAL;
-      case 1: return ABS_LAYOUT;
-      case 2: return STRETCH;
-      case 3: return MULTILINE_STRETCH;
-      case 4: return FLEX_LAYOUT;
-      case 5: return MEASURE;
-      case 6: return ABS_MEASURE;
-      case 7: return FLEX_MEASURE;
-      default: throw new IllegalArgumentException("Unknown enum value: " + value);
-    }
-  }
-}
--- a/java/com/facebook/yoga/YogaConfig.java
+++ b/java/com/facebook/yoga/YogaConfig.java
@@ -11,6 +11,7 @@ import com.facebook.soloader.SoLoader;
 public class YogaConfig {

  public static int SPACING_TYPE = 1;
+  public static boolean useBatchingForLayoutOutputs = false;

  long mNativePointer;
  private YogaLogger mLogger;
--- a/java/com/facebook/yoga/YogaConfigFactory.java
+++ b/java/com/facebook/yoga/YogaConfigFactory.java
@@ -1,7 +0,0 @@
-package com.facebook.yoga;
-
-public abstract class YogaConfigFactory {
-  public static YogaConfig create() {
-    return new YogaConfig();
-  }
-}
--- a/java/com/facebook/yoga/YogaLayoutType.java
+++ b/java/com/facebook/yoga/YogaLayoutType.java
@@ -1,34 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-package com.facebook.yoga;
-
-public enum YogaLayoutType {
-  LAYOUT(0),
-  MEASURE(1),
-  CACHED_LAYOUT(2),
-  CACHED_MEASURE(3);
-
-  private final int mIntValue;
-
-  YogaLayoutType(int intValue) {
-    mIntValue = intValue;
-  }
-
-  public int intValue() {
-    return mIntValue;
-  }
-
-  public static YogaLayoutType fromInt(int value) {
-    switch (value) {
-      case 0: return LAYOUT;
-      case 1: return MEASURE;
-      case 2: return CACHED_LAYOUT;
-      case 3: return CACHED_MEASURE;
-      default: throw new IllegalArgumentException("Unknown enum value: " + value);
-    }
-  }
-}
--- a/java/com/facebook/yoga/YogaNative.java
+++ b/java/com/facebook/yoga/YogaNative.java
@@ -28,8 +28,8 @@ public class YogaNative {


  // YGNode related
-  static native long jni_YGNodeNew();
-  static native long jni_YGNodeNewWithConfig(long configPointer);
+  static native long jni_YGNodeNew(boolean useBatchingForLayoutOutputs);
+  static native long jni_YGNodeNewWithConfig(long configPointer, boolean useBatchingForLayoutOutputs);
  static native void jni_YGNodeFree(long nativePointer);
  static native void jni_YGNodeReset(long nativePointer);
  static native void jni_YGNodeInsertChild(long nativePointer, long childPointer, int index);
--- a/java/com/facebook/yoga/YogaNode.java
+++ b/java/com/facebook/yoga/YogaNode.java
@@ -10,11 +10,11 @@ import javax.annotation.Nullable;

 public abstract class YogaNode {
  public static YogaNode create() {
-    return new YogaNodeJNIFinalizer();
+    return YogaConfig.useBatchingForLayoutOutputs ? new YogaNodeJNIBatching() : new YogaNodeJNI();
  }

  public static YogaNode create(YogaConfig config) {
-    return new YogaNodeJNIFinalizer(config);
+    return YogaConfig.useBatchingForLayoutOutputs ? new YogaNodeJNIBatching(config) : new YogaNodeJNI(config);
  }

  public abstract void reset();
--- a/java/com/facebook/yoga/YogaNodeFactory.java
+++ b/java/com/facebook/yoga/YogaNodeFactory.java
@@ -1,11 +0,0 @@
-package com.facebook.yoga;
-
-public abstract class YogaNodeFactory {
-  public static YogaNode create() {
-    return new YogaNodeJNIFinalizer();
-  }
-
-  public static YogaNode create(YogaConfig config) {
-    return new YogaNodeJNIFinalizer(config);
-  }
-}
--- a/java/com/facebook/yoga/YogaNodeJNI.java
+++ b/java/com/facebook/yoga/YogaNodeJNI.java
@@ -0,0 +1,186 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+package com.facebook.yoga;
+
+import com.facebook.proguard.annotations.DoNotStrip;
+
+@DoNotStrip
+public class YogaNodeJNI extends YogaNodeJNIBase {
+
+  @DoNotStrip
+  private float mWidth = YogaConstants.UNDEFINED;
+  @DoNotStrip
+  private float mHeight = YogaConstants.UNDEFINED;
+  @DoNotStrip
+  private float mTop = YogaConstants.UNDEFINED;
+  @DoNotStrip
+  private float mLeft = YogaConstants.UNDEFINED;
+  @DoNotStrip
+  private float mMarginLeft = 0;
+  @DoNotStrip
+  private float mMarginTop = 0;
+  @DoNotStrip
+  private float mMarginRight = 0;
+  @DoNotStrip
+  private float mMarginBottom = 0;
+  @DoNotStrip
+  private float mPaddingLeft = 0;
+  @DoNotStrip
+  private float mPaddingTop = 0;
+  @DoNotStrip
+  private float mPaddingRight = 0;
+  @DoNotStrip
+  private float mPaddingBottom = 0;
+  @DoNotStrip
+  private float mBorderLeft = 0;
+  @DoNotStrip
+  private float mBorderTop = 0;
+  @DoNotStrip
+  private float mBorderRight = 0;
+  @DoNotStrip
+  private float mBorderBottom = 0;
+  @DoNotStrip
+  private int mLayoutDirection = 0;
+  @DoNotStrip
+  private boolean mHasNewLayout = true;
+  @DoNotStrip
+  private boolean mDoesLegacyStretchFlagAffectsLayout = false;
+
+  public YogaNodeJNI() {
+    super();
+  }
+
+  public YogaNodeJNI(YogaConfig config) {
+    super(config);
+  }
+
+  @Override
+  public void reset() {
+    super.reset();
+    mHasNewLayout = true;
+
+    mWidth = YogaConstants.UNDEFINED;
+    mHeight = YogaConstants.UNDEFINED;
+    mTop = YogaConstants.UNDEFINED;
+    mLeft = YogaConstants.UNDEFINED;
+    mMarginLeft = 0;
+    mMarginTop = 0;
+    mMarginRight = 0;
+    mMarginBottom = 0;
+    mPaddingLeft = 0;
+    mPaddingTop = 0;
+    mPaddingRight = 0;
+    mPaddingBottom = 0;
+    mBorderLeft = 0;
+    mBorderTop = 0;
+    mBorderRight = 0;
+    mBorderBottom = 0;
+    mLayoutDirection = 0;
+
+    mDoesLegacyStretchFlagAffectsLayout = false;
+  }
+
+  @Override
+  public boolean hasNewLayout() {
+    return mHasNewLayout;
+  }
+
+  @Override
+  public void markLayoutSeen() {
+    mHasNewLayout = false;
+  }
+
+  @Override
+  public float getLayoutX() {
+    return mLeft;
+  }
+
+  @Override
+  public float getLayoutY() {
+    return mTop;
+  }
+
+  @Override
+  public float getLayoutWidth() {
+    return mWidth;
+  }
+
+  @Override
+  public float getLayoutHeight() {
+    return mHeight;
+  }
+
+  @Override
+  public boolean getDoesLegacyStretchFlagAffectsLayout() {
+    return mDoesLegacyStretchFlagAffectsLayout;
+  }
+
+  @Override
+  public float getLayoutMargin(YogaEdge edge) {
+    switch (edge) {
+      case LEFT:
+        return mMarginLeft;
+      case TOP:
+        return mMarginTop;
+      case RIGHT:
+        return mMarginRight;
+      case BOTTOM:
+        return mMarginBottom;
+      case START:
+        return getLayoutDirection() == YogaDirection.RTL ? mMarginRight : mMarginLeft;
+      case END:
+        return getLayoutDirection() == YogaDirection.RTL ? mMarginLeft : mMarginRight;
+      default:
+        throw new IllegalArgumentException("Cannot get layout margins of multi-edge shorthands");
+    }
+  }
+
+  @Override
+  public float getLayoutPadding(YogaEdge edge) {
+    switch (edge) {
+      case LEFT:
+        return mPaddingLeft;
+      case TOP:
+        return mPaddingTop;
+      case RIGHT:
+        return mPaddingRight;
+      case BOTTOM:
+        return mPaddingBottom;
+      case START:
+        return getLayoutDirection() == YogaDirection.RTL ? mPaddingRight : mPaddingLeft;
+      case END:
+        return getLayoutDirection() == YogaDirection.RTL ? mPaddingLeft : mPaddingRight;
+      default:
+        throw new IllegalArgumentException("Cannot get layout paddings of multi-edge shorthands");
+    }
+  }
+
+  @Override
+  public float getLayoutBorder(YogaEdge edge) {
+    switch (edge) {
+      case LEFT:
+        return mBorderLeft;
+      case TOP:
+        return mBorderTop;
+      case RIGHT:
+        return mBorderRight;
+      case BOTTOM:
+        return mBorderBottom;
+      case START:
+        return getLayoutDirection() == YogaDirection.RTL ? mBorderRight : mBorderLeft;
+      case END:
+        return getLayoutDirection() == YogaDirection.RTL ? mBorderLeft : mBorderRight;
+      default:
+        throw new IllegalArgumentException("Cannot get layout border of multi-edge shorthands");
+    }
+  }
+
+  @Override
+  public YogaDirection getLayoutDirection() {
+    return YogaDirection.fromInt(mLayoutDirection);
+  }
+}
--- a/java/com/facebook/yoga/YogaNodeJNIBase.java
+++ b/java/com/facebook/yoga/YogaNodeJNIBase.java
@@ -14,60 +14,48 @@ import javax.annotation.Nullable;
@DoNotStrip
 public abstract class YogaNodeJNIBase extends YogaNode implements Cloneable {

-  /* Those flags needs be in sync with YGJNI.cpp */
-  private static final byte MARGIN = 1;
-  private static final byte PADDING = 2;
-  private static final byte BORDER = 4;
-  private static final byte DOES_LEGACY_STRETCH_BEHAVIOUR = 8;
-  private static final byte HAS_NEW_LAYOUT = 16;
-
-  private static final byte LAYOUT_EDGE_SET_FLAG_INDEX = 0;
-  private static final byte LAYOUT_WIDTH_INDEX = 1;
-  private static final byte LAYOUT_HEIGHT_INDEX = 2;
-  private static final byte LAYOUT_LEFT_INDEX = 3;
-  private static final byte LAYOUT_TOP_INDEX = 4;
-  private static final byte LAYOUT_DIRECTION_INDEX = 5;
-  private static final byte LAYOUT_MARGIN_START_INDEX = 6;
-  private static final byte LAYOUT_PADDING_START_INDEX = 10;
-  private static final byte LAYOUT_BORDER_START_INDEX = 14;
-
  @Nullable private YogaNodeJNIBase mOwner;
  @Nullable private List<YogaNodeJNIBase> mChildren;
  @Nullable private YogaMeasureFunction mMeasureFunction;
  @Nullable private YogaBaselineFunction mBaselineFunction;
-  protected long mNativePointer;
+  private long mNativePointer;
  @Nullable private Object mData;

-  @DoNotStrip
-  private @Nullable float[] arr = null;
-
-  @DoNotStrip
-  private int mLayoutDirection = 0;
-
-  private boolean mHasNewLayout = true;
-
-  private YogaNodeJNIBase(long nativePointer) {
-    if (nativePointer == 0) {
+  public YogaNodeJNIBase() {
+    mNativePointer = YogaNative.jni_YGNodeNew(YogaConfig.useBatchingForLayoutOutputs);
+    if (mNativePointer == 0) {
      throw new IllegalStateException("Failed to allocate native memory");
    }
-    mNativePointer = nativePointer;
  }

-  YogaNodeJNIBase() {
-    this(YogaNative.jni_YGNodeNew());
+  public YogaNodeJNIBase(YogaConfig config) {
+    mNativePointer = YogaNative.jni_YGNodeNewWithConfig(config.mNativePointer, YogaConfig.useBatchingForLayoutOutputs);
+    if (mNativePointer == 0) {
+      throw new IllegalStateException("Failed to allocate native memory");
+    }
  }

-  YogaNodeJNIBase(YogaConfig config) {
-    this(YogaNative.jni_YGNodeNewWithConfig(config.mNativePointer));
+  @Override
+  protected void finalize() throws Throwable {
+    try {
+      freeNatives();
+    } finally {
+      super.finalize();
+    }
  }

+  /* frees the native underlying YGNode. Useful for testing. */
+  public void freeNatives() {
+    if (mNativePointer > 0) {
+      long nativePointer = mNativePointer;
+      mNativePointer = 0;
+      YogaNative.jni_YGNodeFree(nativePointer);
+    }
+  }
  public void reset() {
    mMeasureFunction = null;
    mBaselineFunction = null;
    mData = null;
-    arr = null;
-    mHasNewLayout = true;
-    mLayoutDirection = 0;

    YogaNative.jni_YGNodeReset(mNativePointer);
  }
@@ -455,6 +443,8 @@ public abstract class YogaNodeJNIBase extends YogaNode implements Cloneable {
    YogaNative.jni_YGNodeStyleSetAspectRatio(mNativePointer, aspectRatio);
  }

+  public abstract boolean getDoesLegacyStretchFlagAffectsLayout();
+
  public void setMeasureFunction(YogaMeasureFunction measureFunction) {
    mMeasureFunction = measureFunction;
    YogaNative.jni_YGNodeSetHasMeasureFunc(mNativePointer, measureFunction != null);
@@ -540,124 +530,4 @@ public abstract class YogaNodeJNIBase extends YogaNode implements Cloneable {
  private static YogaValue valueFromLong(long raw) {
    return new YogaValue(Float.intBitsToFloat((int) raw), (int) (raw >> 32));
  }
-
-  @Override
-  public float getLayoutX() {
-    return arr != null ? arr[LAYOUT_LEFT_INDEX] : 0;
-  }
-
-  @Override
-  public float getLayoutY() {
-    return arr != null ? arr[LAYOUT_TOP_INDEX] : 0;
-  }
-
-  @Override
-  public float getLayoutWidth() {
-    return arr != null ? arr[LAYOUT_WIDTH_INDEX] : 0;
-  }
-
-  @Override
-  public float getLayoutHeight() {
-    return arr != null ? arr[LAYOUT_HEIGHT_INDEX] : 0;
-  }
-
-  public boolean getDoesLegacyStretchFlagAffectsLayout() {
-    return arr != null && (((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & DOES_LEGACY_STRETCH_BEHAVIOUR) == DOES_LEGACY_STRETCH_BEHAVIOUR);
-  }
-
-  @Override
-  public float getLayoutMargin(YogaEdge edge) {
-    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) {
-      switch (edge) {
-        case LEFT:
-          return arr[LAYOUT_MARGIN_START_INDEX];
-        case TOP:
-          return arr[LAYOUT_MARGIN_START_INDEX + 1];
-        case RIGHT:
-          return arr[LAYOUT_MARGIN_START_INDEX + 2];
-        case BOTTOM:
-          return arr[LAYOUT_MARGIN_START_INDEX + 3];
-        case START:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[LAYOUT_MARGIN_START_INDEX + 2] : arr[LAYOUT_MARGIN_START_INDEX];
-        case END:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[LAYOUT_MARGIN_START_INDEX] : arr[LAYOUT_MARGIN_START_INDEX + 2];
-        default:
-          throw new IllegalArgumentException("Cannot get layout margins of multi-edge shorthands");
-      }
-    } else {
-      return 0;
-    }
-  }
-
-  @Override
-  public float getLayoutPadding(YogaEdge edge) {
-    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & PADDING) == PADDING) {
-      int paddingStartIndex = LAYOUT_PADDING_START_INDEX - ((((int)arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) ? 0 : 4);
-      switch (edge) {
-        case LEFT:
-          return arr[paddingStartIndex];
-        case TOP:
-          return arr[paddingStartIndex + 1];
-        case RIGHT:
-          return arr[paddingStartIndex + 2];
-        case BOTTOM:
-          return arr[paddingStartIndex + 3];
-        case START:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[paddingStartIndex + 2] : arr[paddingStartIndex];
-        case END:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[paddingStartIndex] : arr[paddingStartIndex + 2];
-        default:
-          throw new IllegalArgumentException("Cannot get layout paddings of multi-edge shorthands");
-      }
-    } else {
-      return 0;
-    }
-  }
-
-  @Override
-  public float getLayoutBorder(YogaEdge edge) {
-    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & BORDER) == BORDER) {
-      int borderStartIndex = LAYOUT_BORDER_START_INDEX - ((((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) ? 0 : 4) - ((((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & PADDING) == PADDING) ? 0 : 4);
-      switch (edge) {
-        case LEFT:
-          return arr[borderStartIndex];
-        case TOP:
-          return arr[borderStartIndex + 1];
-        case RIGHT:
-          return arr[borderStartIndex + 2];
-        case BOTTOM:
-          return arr[borderStartIndex + 3];
-        case START:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[borderStartIndex + 2] : arr[borderStartIndex];
-        case END:
-          return getLayoutDirection() == YogaDirection.RTL ? arr[borderStartIndex] : arr[borderStartIndex + 2];
-        default:
-          throw new IllegalArgumentException("Cannot get layout border of multi-edge shorthands");
-      }
-    } else {
-      return 0;
-    }
-  }
-
-  @Override
-  public YogaDirection getLayoutDirection() {
-    return YogaDirection.fromInt(arr != null ? (int) arr[LAYOUT_DIRECTION_INDEX] : mLayoutDirection);
-  }
-
-  @Override
-  public boolean hasNewLayout() {
-    if (arr != null) {
-      return (((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX]) & HAS_NEW_LAYOUT) == HAS_NEW_LAYOUT;
-    } else {
-      return mHasNewLayout;
-    }
-  }
-
-  @Override
-  public void markLayoutSeen() {
-    if (arr != null) {
-      arr[LAYOUT_EDGE_SET_FLAG_INDEX] = ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX]) & ~(HAS_NEW_LAYOUT);
-    }
-    mHasNewLayout = false;
-  }
 }
--- a/java/com/facebook/yoga/YogaNodeJNIBatching.java
+++ b/java/com/facebook/yoga/YogaNodeJNIBatching.java
@@ -0,0 +1,177 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+package com.facebook.yoga;
+
+import javax.annotation.Nullable;
+
+import com.facebook.proguard.annotations.DoNotStrip;
+
+@DoNotStrip
+public class YogaNodeJNIBatching extends YogaNodeJNIBase {
+
+  /* Those flags needs be in sync with YGJNI.cpp */
+  private static final byte MARGIN = 1;
+  private static final byte PADDING = 2;
+  private static final byte BORDER = 4;
+  private static final byte DOES_LEGACY_STRETCH_BEHAVIOUR = 8;
+  private static final byte HAS_NEW_LAYOUT = 16;
+
+  private static final byte LAYOUT_EDGE_SET_FLAG_INDEX = 0;
+  private static final byte LAYOUT_WIDTH_INDEX = 1;
+  private static final byte LAYOUT_HEIGHT_INDEX = 2;
+  private static final byte LAYOUT_LEFT_INDEX = 3;
+  private static final byte LAYOUT_TOP_INDEX = 4;
+  private static final byte LAYOUT_DIRECTION_INDEX = 5;
+  private static final byte LAYOUT_MARGIN_START_INDEX = 6;
+  private static final byte LAYOUT_PADDING_START_INDEX = 10;
+  private static final byte LAYOUT_BORDER_START_INDEX = 14;
+
+  @DoNotStrip
+  private @Nullable float[] arr = null;
+
+  @DoNotStrip
+  private int mLayoutDirection = 0;
+
+  private boolean mHasNewLayout = true;
+
+  public YogaNodeJNIBatching() {
+    super();
+  }
+
+  public YogaNodeJNIBatching(YogaConfig config) {
+    super(config);
+  }
+
+  @Override
+  public void reset() {
+    super.reset();
+    arr = null;
+    mHasNewLayout = true;
+    mLayoutDirection = 0;
+  }
+
+  @Override
+  public float getLayoutX() {
+    return arr != null ? arr[LAYOUT_LEFT_INDEX] : 0;
+  }
+
+  @Override
+  public float getLayoutY() {
+    return arr != null ? arr[LAYOUT_TOP_INDEX] : 0;
+  }
+
+  @Override
+  public float getLayoutWidth() {
+    return arr != null ? arr[LAYOUT_WIDTH_INDEX] : 0;
+  }
+
+  @Override
+  public float getLayoutHeight() {
+    return arr != null ? arr[LAYOUT_HEIGHT_INDEX] : 0;
+  }
+
+  @Override
+  public boolean getDoesLegacyStretchFlagAffectsLayout() {
+    return arr != null && (((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & DOES_LEGACY_STRETCH_BEHAVIOUR) == DOES_LEGACY_STRETCH_BEHAVIOUR);
+  }
+
+  @Override
+  public float getLayoutMargin(YogaEdge edge) {
+    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) {
+      switch (edge) {
+        case LEFT:
+          return arr[LAYOUT_MARGIN_START_INDEX];
+        case TOP:
+          return arr[LAYOUT_MARGIN_START_INDEX + 1];
+        case RIGHT:
+          return arr[LAYOUT_MARGIN_START_INDEX + 2];
+        case BOTTOM:
+          return arr[LAYOUT_MARGIN_START_INDEX + 3];
+        case START:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[LAYOUT_MARGIN_START_INDEX + 2] : arr[LAYOUT_MARGIN_START_INDEX];
+        case END:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[LAYOUT_MARGIN_START_INDEX] : arr[LAYOUT_MARGIN_START_INDEX + 2];
+        default:
+          throw new IllegalArgumentException("Cannot get layout margins of multi-edge shorthands");
+      }
+    } else {
+      return 0;
+    }
+  }
+
+  @Override
+  public float getLayoutPadding(YogaEdge edge) {
+    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & PADDING) == PADDING) {
+      int paddingStartIndex = LAYOUT_PADDING_START_INDEX - ((((int)arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) ? 0 : 4);
+      switch (edge) {
+        case LEFT:
+          return arr[paddingStartIndex];
+        case TOP:
+          return arr[paddingStartIndex + 1];
+        case RIGHT:
+          return arr[paddingStartIndex + 2];
+        case BOTTOM:
+          return arr[paddingStartIndex + 3];
+        case START:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[paddingStartIndex + 2] : arr[paddingStartIndex];
+        case END:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[paddingStartIndex] : arr[paddingStartIndex + 2];
+        default:
+          throw new IllegalArgumentException("Cannot get layout paddings of multi-edge shorthands");
+      }
+    } else {
+      return 0;
+    }
+  }
+
+  @Override
+  public float getLayoutBorder(YogaEdge edge) {
+    if (arr != null && ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & BORDER) == BORDER) {
+      int borderStartIndex = LAYOUT_BORDER_START_INDEX - ((((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & MARGIN) == MARGIN) ? 0 : 4) - ((((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX] & PADDING) == PADDING) ? 0 : 4);
+      switch (edge) {
+        case LEFT:
+          return arr[borderStartIndex];
+        case TOP:
+          return arr[borderStartIndex + 1];
+        case RIGHT:
+          return arr[borderStartIndex + 2];
+        case BOTTOM:
+          return arr[borderStartIndex + 3];
+        case START:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[borderStartIndex + 2] : arr[borderStartIndex];
+        case END:
+          return getLayoutDirection() == YogaDirection.RTL ? arr[borderStartIndex] : arr[borderStartIndex + 2];
+        default:
+          throw new IllegalArgumentException("Cannot get layout border of multi-edge shorthands");
+      }
+    } else {
+      return 0;
+    }
+  }
+
+  @Override
+  public YogaDirection getLayoutDirection() {
+    return YogaDirection.fromInt(arr != null ? (int) arr[LAYOUT_DIRECTION_INDEX] : mLayoutDirection);
+  }
+
+  @Override
+  public boolean hasNewLayout() {
+    if (arr != null) {
+      return (((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX]) & HAS_NEW_LAYOUT) == HAS_NEW_LAYOUT;
+    } else {
+      return mHasNewLayout;
+    }
+  }
+
+  @Override
+  public void markLayoutSeen() {
+    if (arr != null) {
+      arr[LAYOUT_EDGE_SET_FLAG_INDEX] = ((int) arr[LAYOUT_EDGE_SET_FLAG_INDEX]) & ~(HAS_NEW_LAYOUT);
+    }
+    mHasNewLayout = false;
+  }
+}
--- a/java/com/facebook/yoga/YogaNodeJNIFinalizer.java
+++ b/java/com/facebook/yoga/YogaNodeJNIFinalizer.java
@@ -1,34 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-package com.facebook.yoga;
-
-public class YogaNodeJNIFinalizer extends YogaNodeJNIBase {
-  public YogaNodeJNIFinalizer() {
-    super();
-  }
-
-  public YogaNodeJNIFinalizer(YogaConfig config) {
-    super(config);
-  }
-
-  @Override
-  protected void finalize() throws Throwable {
-    try {
-      freeNatives();
-    } finally {
-      super.finalize();
-    }
-   }
-
-  public void freeNatives() {
-    if (mNativePointer != 0) {
-      long nativePointer = mNativePointer;
-      mNativePointer = 0;
-      YogaNative.jni_YGNodeFree(nativePointer);
-    }
-  }
-}
--- a/java/jni/YGJNI.cpp
+++ b/java/jni/YGJNI.cpp
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-#include <fbjni/fbjni.h>
+#include <fb/fbjni.h>
 #include <yoga/YGNode.h>
 #include <yoga/Yoga.h>
 #include <yoga/Yoga-internal.h>
@@ -73,6 +73,8 @@ const short int LAYOUT_MARGIN_START_INDEX = 6;
 const short int LAYOUT_PADDING_START_INDEX = 10;
 const short int LAYOUT_BORDER_START_INDEX = 14;

+bool useBatchingForLayoutOutputs;
+
 namespace {

 union YGNodeContext {
@@ -163,56 +165,141 @@ static void YGTransferLayoutOutputsRecursive(

  auto edgesSet = YGNodeEdges{root};

-  bool marginFieldSet = edgesSet.has(YGNodeEdges::MARGIN);
-  bool paddingFieldSet = edgesSet.has(YGNodeEdges::PADDING);
-  bool borderFieldSet = edgesSet.has(YGNodeEdges::BORDER);
+  if (useBatchingForLayoutOutputs) {
+    bool marginFieldSet = edgesSet.has(YGNodeEdges::MARGIN);
+    bool paddingFieldSet = edgesSet.has(YGNodeEdges::PADDING);
+    bool borderFieldSet = edgesSet.has(YGNodeEdges::BORDER);

-  int fieldFlags = edgesSet.get();
-  fieldFlags |= HAS_NEW_LAYOUT;
-  if (YGNodeLayoutGetDidLegacyStretchFlagAffectLayout(root)) {
-    fieldFlags |= DOES_LEGACY_STRETCH_BEHAVIOUR;
-  }
+    int fieldFlags = edgesSet.get();
+    fieldFlags |= HAS_NEW_LAYOUT;
+    if (YGNodeLayoutGetDidLegacyStretchFlagAffectLayout(root)) {
+      fieldFlags |= DOES_LEGACY_STRETCH_BEHAVIOUR;
+    }

-  const int arrSize = 6 + (marginFieldSet ? 4 : 0) + (paddingFieldSet ? 4 : 0) +
-      (borderFieldSet ? 4 : 0);
-  float arr[18];
-  arr[LAYOUT_EDGE_SET_FLAG_INDEX] = fieldFlags;
-  arr[LAYOUT_WIDTH_INDEX] = YGNodeLayoutGetWidth(root);
-  arr[LAYOUT_HEIGHT_INDEX] = YGNodeLayoutGetHeight(root);
-  arr[LAYOUT_LEFT_INDEX] = YGNodeLayoutGetLeft(root);
-  arr[LAYOUT_TOP_INDEX] = YGNodeLayoutGetTop(root);
-  arr[LAYOUT_DIRECTION_INDEX] =
-      static_cast<jint>(YGNodeLayoutGetDirection(root));
-  if (marginFieldSet) {
-    arr[LAYOUT_MARGIN_START_INDEX] = YGNodeLayoutGetMargin(root, YGEdgeLeft);
-    arr[LAYOUT_MARGIN_START_INDEX + 1] = YGNodeLayoutGetMargin(root, YGEdgeTop);
-    arr[LAYOUT_MARGIN_START_INDEX + 2] =
-        YGNodeLayoutGetMargin(root, YGEdgeRight);
-    arr[LAYOUT_MARGIN_START_INDEX + 3] =
-        YGNodeLayoutGetMargin(root, YGEdgeBottom);
-  }
-  if (paddingFieldSet) {
-    int paddingStartIndex =
-        LAYOUT_PADDING_START_INDEX - (marginFieldSet ? 0 : 4);
-    arr[paddingStartIndex] = YGNodeLayoutGetPadding(root, YGEdgeLeft);
-    arr[paddingStartIndex + 1] = YGNodeLayoutGetPadding(root, YGEdgeTop);
-    arr[paddingStartIndex + 2] = YGNodeLayoutGetPadding(root, YGEdgeRight);
-    arr[paddingStartIndex + 3] = YGNodeLayoutGetPadding(root, YGEdgeBottom);
-  }
+    const int arrSize = 6 + (marginFieldSet ? 4 : 0) +
+        (paddingFieldSet ? 4 : 0) + (borderFieldSet ? 4 : 0);
+    float arr[18];
+    arr[LAYOUT_EDGE_SET_FLAG_INDEX] = fieldFlags;
+    arr[LAYOUT_WIDTH_INDEX] = YGNodeLayoutGetWidth(root);
+    arr[LAYOUT_HEIGHT_INDEX] = YGNodeLayoutGetHeight(root);
+    arr[LAYOUT_LEFT_INDEX] = YGNodeLayoutGetLeft(root);
+    arr[LAYOUT_TOP_INDEX] = YGNodeLayoutGetTop(root);
+    arr[LAYOUT_DIRECTION_INDEX] =
+        static_cast<jint>(YGNodeLayoutGetDirection(root));
+    if (marginFieldSet) {
+      arr[LAYOUT_MARGIN_START_INDEX] = YGNodeLayoutGetMargin(root, YGEdgeLeft);
+      arr[LAYOUT_MARGIN_START_INDEX + 1] =
+          YGNodeLayoutGetMargin(root, YGEdgeTop);
+      arr[LAYOUT_MARGIN_START_INDEX + 2] =
+          YGNodeLayoutGetMargin(root, YGEdgeRight);
+      arr[LAYOUT_MARGIN_START_INDEX + 3] =
+          YGNodeLayoutGetMargin(root, YGEdgeBottom);
+    }
+    if (paddingFieldSet) {
+      int paddingStartIndex =
+          LAYOUT_PADDING_START_INDEX - (marginFieldSet ? 0 : 4);
+      arr[paddingStartIndex] = YGNodeLayoutGetPadding(root, YGEdgeLeft);
+      arr[paddingStartIndex + 1] = YGNodeLayoutGetPadding(root, YGEdgeTop);
+      arr[paddingStartIndex + 2] = YGNodeLayoutGetPadding(root, YGEdgeRight);
+      arr[paddingStartIndex + 3] = YGNodeLayoutGetPadding(root, YGEdgeBottom);
+    }

-  if (borderFieldSet) {
-    int borderStartIndex = LAYOUT_BORDER_START_INDEX -
-        (marginFieldSet ? 0 : 4) - (paddingFieldSet ? 0 : 4);
-    arr[borderStartIndex] = YGNodeLayoutGetBorder(root, YGEdgeLeft);
-    arr[borderStartIndex + 1] = YGNodeLayoutGetBorder(root, YGEdgeTop);
-    arr[borderStartIndex + 2] = YGNodeLayoutGetBorder(root, YGEdgeRight);
-    arr[borderStartIndex + 3] = YGNodeLayoutGetBorder(root, YGEdgeBottom);
-  }
+    if (borderFieldSet) {
+      int borderStartIndex = LAYOUT_BORDER_START_INDEX -
+          (marginFieldSet ? 0 : 4) - (paddingFieldSet ? 0 : 4);
+      arr[borderStartIndex] = YGNodeLayoutGetBorder(root, YGEdgeLeft);
+      arr[borderStartIndex + 1] = YGNodeLayoutGetBorder(root, YGEdgeTop);
+      arr[borderStartIndex + 2] = YGNodeLayoutGetBorder(root, YGEdgeRight);
+      arr[borderStartIndex + 3] = YGNodeLayoutGetBorder(root, YGEdgeBottom);
+    }

-  static auto arrField = obj->getClass()->getField<jfloatArray>("arr");
-  local_ref<jfloatArray> arrFinal = make_float_array(arrSize);
-  arrFinal->setRegion(0, arrSize, arr);
-  obj->setFieldValue<jfloatArray>(arrField, arrFinal.get());
+    static auto arrField = obj->getClass()->getField<jfloatArray>("arr");
+    local_ref<jfloatArray> arrFinal = make_float_array(arrSize);
+    arrFinal->setRegion(0, arrSize, arr);
+    obj->setFieldValue<jfloatArray>(arrField, arrFinal.get());
+
+  } else {
+    static auto widthField = obj->getClass()->getField<jfloat>("mWidth");
+    static auto heightField = obj->getClass()->getField<jfloat>("mHeight");
+    static auto leftField = obj->getClass()->getField<jfloat>("mLeft");
+    static auto topField = obj->getClass()->getField<jfloat>("mTop");
+
+    static auto marginLeftField =
+        obj->getClass()->getField<jfloat>("mMarginLeft");
+    static auto marginTopField =
+        obj->getClass()->getField<jfloat>("mMarginTop");
+    static auto marginRightField =
+        obj->getClass()->getField<jfloat>("mMarginRight");
+    static auto marginBottomField =
+        obj->getClass()->getField<jfloat>("mMarginBottom");
+
+    static auto paddingLeftField =
+        obj->getClass()->getField<jfloat>("mPaddingLeft");
+    static auto paddingTopField =
+        obj->getClass()->getField<jfloat>("mPaddingTop");
+    static auto paddingRightField =
+        obj->getClass()->getField<jfloat>("mPaddingRight");
+    static auto paddingBottomField =
+        obj->getClass()->getField<jfloat>("mPaddingBottom");
+
+    static auto borderLeftField =
+        obj->getClass()->getField<jfloat>("mBorderLeft");
+    static auto borderTopField =
+        obj->getClass()->getField<jfloat>("mBorderTop");
+    static auto borderRightField =
+        obj->getClass()->getField<jfloat>("mBorderRight");
+    static auto borderBottomField =
+        obj->getClass()->getField<jfloat>("mBorderBottom");
+
+    static auto hasNewLayoutField =
+        obj->getClass()->getField<jboolean>("mHasNewLayout");
+    static auto doesLegacyStretchBehaviour =
+        obj->getClass()->getField<jboolean>(
+            "mDoesLegacyStretchFlagAffectsLayout");
+
+    obj->setFieldValue(widthField, YGNodeLayoutGetWidth(root));
+    obj->setFieldValue(heightField, YGNodeLayoutGetHeight(root));
+    obj->setFieldValue(leftField, YGNodeLayoutGetLeft(root));
+    obj->setFieldValue(topField, YGNodeLayoutGetTop(root));
+    obj->setFieldValue<jboolean>(
+        doesLegacyStretchBehaviour,
+        YGNodeLayoutGetDidLegacyStretchFlagAffectLayout(root));
+    obj->setFieldValue<jboolean>(hasNewLayoutField, true);
+    YGTransferLayoutDirection(root, obj);
+
+    if (edgesSet.has(YGNodeEdges::MARGIN)) {
+      obj->setFieldValue(
+          marginLeftField, YGNodeLayoutGetMargin(root, YGEdgeLeft));
+      obj->setFieldValue(
+          marginTopField, YGNodeLayoutGetMargin(root, YGEdgeTop));
+      obj->setFieldValue(
+          marginRightField, YGNodeLayoutGetMargin(root, YGEdgeRight));
+      obj->setFieldValue(
+          marginBottomField, YGNodeLayoutGetMargin(root, YGEdgeBottom));
+    }
+
+    if (edgesSet.has(YGNodeEdges::PADDING)) {
+      obj->setFieldValue(
+          paddingLeftField, YGNodeLayoutGetPadding(root, YGEdgeLeft));
+      obj->setFieldValue(
+          paddingTopField, YGNodeLayoutGetPadding(root, YGEdgeTop));
+      obj->setFieldValue(
+          paddingRightField, YGNodeLayoutGetPadding(root, YGEdgeRight));
+      obj->setFieldValue(
+          paddingBottomField, YGNodeLayoutGetPadding(root, YGEdgeBottom));
+    }
+
+    if (edgesSet.has(YGNodeEdges::BORDER)) {
+      obj->setFieldValue(
+          borderLeftField, YGNodeLayoutGetBorder(root, YGEdgeLeft));
+      obj->setFieldValue(
+          borderTopField, YGNodeLayoutGetBorder(root, YGEdgeTop));
+      obj->setFieldValue(
+          borderRightField, YGNodeLayoutGetBorder(root, YGEdgeRight));
+      obj->setFieldValue(
+          borderBottomField, YGNodeLayoutGetBorder(root, YGEdgeBottom));
+    }
+  }

  root->setHasNewLayout(false);

@@ -323,16 +410,21 @@ static int YGJNILogFunc(
  return result;
 }

-jlong jni_YGNodeNew(alias_ref<jobject> thiz) {
+jlong jni_YGNodeNew(alias_ref<jobject> thiz, jboolean useBatching) {
  const YGNodeRef node = YGNodeNew();
  node->setContext(YGNodeContext{}.asVoidPtr);
  node->setPrintFunc(YGPrint);
+  useBatchingForLayoutOutputs = useBatching;
  return reinterpret_cast<jlong>(node);
 }

-jlong jni_YGNodeNewWithConfig(alias_ref<jclass>, jlong configPointer) {
+jlong jni_YGNodeNewWithConfig(
+    alias_ref<jclass>,
+    jlong configPointer,
+    jboolean useBatching) {
  const YGNodeRef node = YGNodeNewWithConfig(_jlong2YGConfigRef(configPointer));
  node->setContext(YGNodeContext{}.asVoidPtr);
+  useBatchingForLayoutOutputs = useBatching;
  return reinterpret_cast<jlong>(node);
 }

--- a/java/jni/YGJTypes.h
+++ b/java/jni/YGJTypes.h
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-#include <fbjni/fbjni.h>
+#include <fb/fbjni.h>
 #include <yoga/YGValue.h>
 #include <yoga/Yoga.h>
 #include <map>
--- a/java/proguard-annotations/build.gradle
+++ b/java/proguard-annotations/build.gradle
@@ -6,8 +6,3 @@
 */

 apply plugin: 'java'
-
-sourceCompatibility = '1.7'
-targetCompatibility = '1.7'
-
-apply from: rootProject.file('gradle/release.gradle')
--- a/java/proguard-annotations/gradle.properties
+++ b/java/proguard-annotations/gradle.properties
@@ -1,12 +0,0 @@
-#
-#  Copyright (c) Facebook, Inc. and its affiliates.
-#
-#  This source code is licensed under the MIT license found in the LICENSE
-#  file in the root directory of this source tree.
-#
-
-GROUP=com.facebook.yoga
-POM_NAME=Proguard Annotations
-POM_DESCRIPTION=Shared annotations for use with Proguard
-POM_ARTIFACT_ID=proguard-annotations
-POM_PACKAGING=jar
--- a/java/proguard-annotations/src/main/java/com/facebook/proguard/annotations/BUCK
+++ b/java/proguard-annotations/src/main/java/com/facebook/proguard/annotations/BUCK
@@ -3,13 +3,13 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.

-load("//tools/build_defs/oss:yoga_defs.bzl", "yoga_java_library")
+load("//tools/build_defs/oss:yoga_defs.bzl", "YOGA_ROOTS", "yoga_java_library")

 yoga_java_library(
    name = "annotations",
    srcs = glob(["*.java"]),
    source = "1.7",
    target = "1.7",
-    visibility = ["PUBLIC"],
+    visibility = YOGA_ROOTS,
    deps = [],
 )
--- a/javascript/binding.gyp
+++ b/javascript/binding.gyp
@@ -7,9 +7,9 @@

    	"sources": [
            "<!@(ls -1 sources/yoga/*.cpp)",
-            "<!@(ls -1 sources/yoga/*/*.cpp)",
            "sources/Config.cc",
            "sources/Node.cc",
+            "sources/global.cc",
    	    "sources/nbind.cc"
    	],

--- a/javascript/package.json
+++ b/javascript/package.json
@@ -43,7 +43,7 @@
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-stage-3": "^6.24.1",
    "cross-env": "^4.0.0",
-    "flow-copy-source": "^2.0.7",
+    "flow-copy-source": "^1.2.1",
    "mocha": "^3.2.0"
  }
 }
--- a/javascript/sources/entry-common.js
+++ b/javascript/sources/entry-common.js
@@ -350,6 +350,9 @@ module.exports = (bind: any, lib: any): Yoga => {
    Layout: bind('Layout', Layout),
    Size: bind('Size', Size),
    Value: bind('Value', Value),
+    getInstanceCount(...args) {
+      return lib.getInstanceCount(...args);
+    },
    ...CONSTANTS,
  };
 };
--- a/javascript/sources/global.hh
+++ b/javascript/sources/global.hh
@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+unsigned getInstanceCount(void);
--- a/javascript/sources/nbind.cc
+++ b/javascript/sources/nbind.cc
@@ -11,9 +11,14 @@
 #include "./Size.hh"
 #include "./Value.hh"
 #include "./Config.hh"
+#include "./global.hh"

 #include <nbind/nbind.h>

+NBIND_GLOBAL() {
+  function(getInstanceCount);
+}
+
 NBIND_CLASS(Size) {
  construct<>();
  construct<double, double>();
--- a/javascript/tests/Facebook.Yoga/YGComputedBorderTest.js
+++ b/javascript/tests/Facebook.Yoga/YGComputedBorderTest.js
@@ -27,5 +27,5 @@ it("border_start", function () {
    root.freeRecursive();

  (typeof gc !== "undefined") && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/tests/Facebook.Yoga/YGComputedMarginTest.js
+++ b/javascript/tests/Facebook.Yoga/YGComputedMarginTest.js
@@ -27,5 +27,5 @@ it("margin_start", function () {
    root.freeRecursive();

  (typeof gc !== "undefined") && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/tests/Facebook.Yoga/YGComputedPaddingTest.js
+++ b/javascript/tests/Facebook.Yoga/YGComputedPaddingTest.js
@@ -27,5 +27,5 @@ it("padding_start", function () {
    root.freeRecursive();

  (typeof gc !== "undefined") && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/tests/Facebook.Yoga/YGDirtiedTest.js
+++ b/javascript/tests/Facebook.Yoga/YGDirtiedTest.js
@@ -34,7 +34,7 @@ it("dirtied", function() {
    root.freeRecursive();

  typeof gc !== "undefined" && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });

 it("dirtied_propagation", function() {
@@ -75,7 +75,7 @@ it("dirtied_propagation", function() {
    root.freeRecursive();

  typeof gc !== "undefined" && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });

 it("dirtied_hierarchy", function() {
@@ -122,7 +122,7 @@ it("dirtied_hierarchy", function() {
    root.freeRecursive();

  typeof gc !== "undefined" && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });

 it("dirtied_reset", function() {
@@ -164,5 +164,5 @@ it("dirtied_reset", function() {
    root.freeRecursive();

  typeof gc !== "undefined" && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/tests/Facebook.Yoga/YGMeasureCacheTest.js
+++ b/javascript/tests/Facebook.Yoga/YGMeasureCacheTest.js
@@ -29,5 +29,5 @@ it("measure_once_single_flexible_child", function () {
    root.freeRecursive();

  (typeof gc !== "undefined") && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/tests/Facebook.Yoga/YGMeasureTest.js
+++ b/javascript/tests/Facebook.Yoga/YGMeasureTest.js
@@ -27,5 +27,5 @@ it("dont_measure_single_grow_shrink_child", function () {
    root.freeRecursive();

  (typeof gc !== "undefined") && gc();
-  // TODO Add event support in js and check instace allocation and de allocation using that
+  console.assert(0 === Yoga.getInstanceCount(), "0 === Yoga.getInstanceCount() (" + Yoga.getInstanceCount() + ")");
 });
--- a/javascript/yarn.lock
+++ b/javascript/yarn.lock
@@ -10,22 +10,14 @@ ansi-regex@^2.0.0:
  version "2.0.0"
  resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-2.0.0.tgz#c5061b6e0ef8a81775e50f5d66151bf6bf371107"

-ansi-regex@^4.1.0:
-  version "4.1.0"
-  resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-4.1.0.tgz#8b9f8f08cf1acb843756a839ca8c7e3168c51997"
-  integrity sha512-1apePfXM1UOSqw0o9IiFAovVz9M5S1Dg+4TrDwfMewQ6p/rmMueb7tWZjQ1rx4Loy1ArBggoqGpfqqdI4rondg==
+ansi-regex@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-3.0.0.tgz#ed0317c322064f79466c02966bddb605ab37d998"

 ansi-styles@^2.2.1:
  version "2.2.1"
  resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-2.2.1.tgz#b432dd3358b634cf75e1e4664368240533c1ddbe"

-ansi-styles@^3.2.0:
-  version "3.2.1"
-  resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-3.2.1.tgz#41fbb20243e50b12be0f04b8dedbf07520ce841d"
-  integrity sha512-VT0ZI6kZRdTh8YyJw3SMbYm/u+NqfsAxEpWO0Pf9sq8/e94WxxOpPKx9FR1FlyCtOVDNOQ+8ntlqFxiRc+r5qA==
-  dependencies:
-    color-convert "^1.9.0"
-
 anymatch@^1.3.0:
  version "1.3.0"
  resolved "https://registry.yarnpkg.com/anymatch/-/anymatch-1.3.0.tgz#a3e52fa39168c825ff57b0248126ce5a8ff95507"
@@ -33,14 +25,6 @@ anymatch@^1.3.0:
    arrify "^1.0.0"
    micromatch "^2.1.5"

-anymatch@^3.0.1:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/anymatch/-/anymatch-3.0.3.tgz#2fb624fe0e84bccab00afee3d0006ed310f22f09"
-  integrity sha512-c6IvoeBECQlMVuYUjSwimnhmztImpErfxJzWZhIQinIvQWoGOnB0dLIgifbPHQt5heS6mNlaZG16f06H3C8t1g==
-  dependencies:
-    normalize-path "^3.0.0"
-    picomatch "^2.0.4"
-
 aproba@^1.0.3:
  version "1.0.4"
  resolved "https://registry.yarnpkg.com/aproba/-/aproba-1.0.4.tgz#2713680775e7614c8ba186c065d4e2e52d1072c0"
@@ -703,11 +687,6 @@ binary-extensions@^1.0.0:
  version "1.8.0"
  resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.8.0.tgz#48ec8d16df4377eae5fa5884682480af4d95c774"

-binary-extensions@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-2.0.0.tgz#23c0df14f6a88077f5f986c0d167ec03c3d5537c"
-  integrity sha512-Phlt0plgpIIBOGTT/ehfFnbNlfsDEiqmzE2KRXoX1bLIlir4X/MR+zSyBEkL05ffWgnRSf/DXv+WrUAVr93/ow==
-
 block-stream@*:
  version "0.0.9"
  resolved "https://registry.yarnpkg.com/block-stream/-/block-stream-0.0.9.tgz#13ebfe778a03205cfe03751481ebb4b3300c126a"
@@ -739,13 +718,6 @@ braces@^1.8.2:
    preserve "^0.2.0"
    repeat-element "^1.1.2"

-braces@^3.0.2:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/braces/-/braces-3.0.2.tgz#3454e1a462ee8d599e236df336cd9ea4f8afe107"
-  integrity sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==
-  dependencies:
-    fill-range "^7.0.1"
-
 browser-stdout@1.3.0:
  version "1.3.0"
  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.0.tgz#f351d32969d32fa5d7a5567154263d928ae3bd1f"
@@ -754,10 +726,13 @@ buffer-shims@^1.0.0:
  version "1.0.0"
  resolved "https://registry.yarnpkg.com/buffer-shims/-/buffer-shims-1.0.0.tgz#9978ce317388c649ad8793028c3477ef044a8b51"

-camelcase@^5.0.0:
-  version "5.3.1"
-  resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-5.3.1.tgz#e3c9b31569e106811df242f715725a1f4c494320"
-  integrity sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg==
+builtin-modules@^1.0.0:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/builtin-modules/-/builtin-modules-1.1.1.tgz#270f076c5a72c02f5b65a47df94c5fe3a278892f"
+
+camelcase@^4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-4.1.0.tgz#d545635be1e33c542649c69173e5de6acfae34dd"

 caseless@~0.11.0:
  version "0.11.0"
@@ -788,46 +763,33 @@ chokidar@^1.6.1:
  optionalDependencies:
    fsevents "^1.0.0"

-chokidar@^3.0.0:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.0.2.tgz#0d1cd6d04eb2df0327446188cd13736a3367d681"
-  integrity sha512-c4PR2egjNjI1um6bamCQ6bUNPDiyofNQruHvKgHQ4gDUP/ITSVSzNsiI5OWtHOsX323i5ha/kk4YmOZ1Ktg7KA==
+chokidar@^1.7.0:
+  version "1.7.0"
+  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-1.7.0.tgz#798e689778151c8076b4b360e5edd28cda2bb468"
  dependencies:
-    anymatch "^3.0.1"
-    braces "^3.0.2"
-    glob-parent "^5.0.0"
-    is-binary-path "^2.1.0"
-    is-glob "^4.0.1"
-    normalize-path "^3.0.0"
-    readdirp "^3.1.1"
+    anymatch "^1.3.0"
+    async-each "^1.0.0"
+    glob-parent "^2.0.0"
+    inherits "^2.0.1"
+    is-binary-path "^1.0.0"
+    is-glob "^2.0.0"
+    path-is-absolute "^1.0.0"
+    readdirp "^2.0.0"
  optionalDependencies:
-    fsevents "^2.0.6"
+    fsevents "^1.0.0"

-cliui@^5.0.0:
-  version "5.0.0"
-  resolved "https://registry.yarnpkg.com/cliui/-/cliui-5.0.0.tgz#deefcfdb2e800784aa34f46fa08e06851c7bbbc5"
-  integrity sha512-PYeGSEmmHM6zvoef2w8TPzlrnNpXIjTipYK780YswmIP9vjxmd6Y2a3CB2Ks6/AU8NHjZugXvo8w3oWM2qnwXA==
+cliui@^3.2.0:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/cliui/-/cliui-3.2.0.tgz#120601537a916d29940f934da3b48d585a39213d"
  dependencies:
-    string-width "^3.1.0"
-    strip-ansi "^5.2.0"
-    wrap-ansi "^5.1.0"
+    string-width "^1.0.1"
+    strip-ansi "^3.0.1"
+    wrap-ansi "^2.0.0"

 code-point-at@^1.0.0:
  version "1.1.0"
  resolved "https://registry.yarnpkg.com/code-point-at/-/code-point-at-1.1.0.tgz#0d070b4d043a5bea33a2f1a40e2edb3d9a4ccf77"

-color-convert@^1.9.0:
-  version "1.9.3"
-  resolved "https://registry.yarnpkg.com/color-convert/-/color-convert-1.9.3.tgz#bb71850690e1f136567de629d2d5471deda4c1e8"
-  integrity sha512-QfAUtd+vFdAtFQcC8CCyYt1fYWxSqAiK2cSD6zDB8N3cpsEBAvRxp9zOGg6G/SHHJYAT88/az/IuDGALsNVbGg==
-  dependencies:
-    color-name "1.1.3"
-
-color-name@1.1.3:
-  version "1.1.3"
-  resolved "https://registry.yarnpkg.com/color-name/-/color-name-1.1.3.tgz#a7d0558bd89c42f795dd42328f740831ca53bc25"
-  integrity sha1-p9BVi9icQveV3UIyj3QIMcpTvCU=
-
 combined-stream@^1.0.5, combined-stream@~1.0.5:
  version "1.0.5"
  resolved "https://registry.yarnpkg.com/combined-stream/-/combined-stream-1.0.5.tgz#938370a57b4a51dea2c77c15d5c5fdf895164009"
@@ -867,7 +829,7 @@ cross-env@^4.0.0:
    cross-spawn "^5.1.0"
    is-windows "^1.0.0"

-cross-spawn@^5.1.0:
+cross-spawn@^5.0.1, cross-spawn@^5.1.0:
  version "5.1.0"
  resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-5.1.0.tgz#e8bd0efee58fcff6f8f94510a0a554bbfa235449"
  dependencies:
@@ -899,10 +861,9 @@ debug@^2.6.8:
  dependencies:
    ms "2.0.0"

-decamelize@^1.2.0:
+decamelize@^1.1.1:
  version "1.2.0"
  resolved "https://registry.yarnpkg.com/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"
-  integrity sha1-9lNNFRSCabIDUue+4m9QH5oZEpA=

 deep-extend@~0.4.0:
  version "0.4.1"
@@ -932,15 +893,16 @@ ecc-jsbn@~0.1.1:
  dependencies:
    jsbn "~0.1.0"

-emoji-regex@^7.0.1:
-  version "7.0.3"
-  resolved "https://registry.yarnpkg.com/emoji-regex/-/emoji-regex-7.0.3.tgz#933a04052860c85e83c122479c4748a8e4c72156"
-  integrity sha512-CwBLREIQ7LvYFB0WyRvwhq5N5qPhc6PMjD6bYggFlI5YyDgl+0vxq5VHbMOFqLg7hfWzmu8T5Z1QofhmTIhItA==
-
 emscripten-library-decorator@~0.2.2:
  version "0.2.2"
  resolved "https://registry.yarnpkg.com/emscripten-library-decorator/-/emscripten-library-decorator-0.2.2.tgz#d035f023e2a84c68305cc842cdeea38e67683c40"

+error-ex@^1.2.0:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/error-ex/-/error-ex-1.3.1.tgz#f855a86ce61adc4e8621c3cda21e7a7612c3a8dc"
+  dependencies:
+    is-arrayish "^0.2.1"
+
 escape-string-regexp@1.0.5, escape-string-regexp@^1.0.2:
  version "1.0.5"
  resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
@@ -949,6 +911,18 @@ esutils@^2.0.2:
  version "2.0.2"
  resolved "https://registry.yarnpkg.com/esutils/-/esutils-2.0.2.tgz#0abf4f1caa5bcb1f7a9d8acc6dea4faaa04bac9b"

+execa@^0.7.0:
+  version "0.7.0"
+  resolved "https://registry.yarnpkg.com/execa/-/execa-0.7.0.tgz#944becd34cc41ee32a63a9faf27ad5a65fc59777"
+  dependencies:
+    cross-spawn "^5.0.1"
+    get-stream "^3.0.0"
+    is-stream "^1.1.0"
+    npm-run-path "^2.0.0"
+    p-finally "^1.0.0"
+    signal-exit "^3.0.0"
+    strip-eof "^1.0.0"
+
 expand-brackets@^0.1.4:
  version "0.1.5"
  resolved "https://registry.yarnpkg.com/expand-brackets/-/expand-brackets-0.1.5.tgz#df07284e342a807cd733ac5af72411e581d1177b"
@@ -989,30 +963,21 @@ fill-range@^2.1.0:
    repeat-element "^1.1.2"
    repeat-string "^1.5.2"

-fill-range@^7.0.1:
-  version "7.0.1"
-  resolved "https://registry.yarnpkg.com/fill-range/-/fill-range-7.0.1.tgz#1919a6a7c75fe38b2c7c77e5198535da9acdda40"
-  integrity sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==
+find-up@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/find-up/-/find-up-2.1.0.tgz#45d1b7e506c717ddd482775a2b77920a3c0c57a7"
  dependencies:
-    to-regex-range "^5.0.1"
+    locate-path "^2.0.0"

-find-up@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/find-up/-/find-up-3.0.0.tgz#49169f1d7993430646da61ecc5ae355c21c97b73"
-  integrity sha512-1yD6RmLI1XBfxugvORwlck6f75tYL+iR0jqwsOrOxMZyGYqUuDhJ0l4AXdO1iX/FTs9cBAMEk1gWSEx1kSbylg==
+flow-copy-source@^1.2.1:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/flow-copy-source/-/flow-copy-source-1.2.1.tgz#705c2fa8fb29a281118e1c4b66218dec24b745ec"
  dependencies:
-    locate-path "^3.0.0"
-
-flow-copy-source@^2.0.7:
-  version "2.0.7"
-  resolved "https://registry.yarnpkg.com/flow-copy-source/-/flow-copy-source-2.0.7.tgz#3b5634ac552c539a40093ed09d9e645e67f95212"
-  integrity sha512-/9oYivwSRgIyRMWqRkzJgulUCRPqMA8JSt7l0uoW0Xmtp8ItJpURnBczJUvnAKnHp0TNttNILCeuqW2w9cwTFg==
-  dependencies:
-    chokidar "^3.0.0"
-    fs-extra "^8.1.0"
+    chokidar "^1.7.0"
+    fs-extra "^3.0.1"
    glob "^7.0.0"
    kefir "^3.7.3"
-    yargs "^13.1.0"
+    yargs "^8.0.2"

 for-in@^0.1.5:
  version "0.1.6"
@@ -1036,13 +1001,12 @@ form-data@~2.1.1:
    combined-stream "^1.0.5"
    mime-types "^2.1.12"

-fs-extra@^8.1.0:
-  version "8.1.0"
-  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-8.1.0.tgz#49d43c45a88cd9677668cb7be1b46efdb8d2e1c0"
-  integrity sha512-yhlQgA6mnOJUKOsRUFsgJdQCvkKhcz8tlZG5HBQfReYZy46OwLcY+Zia0mtdHsOo9y/hP+CxMN0TU9QxoOtG4g==
+fs-extra@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-3.0.1.tgz#3794f378c58b342ea7dbbb23095109c4b3b62291"
  dependencies:
-    graceful-fs "^4.2.0"
-    jsonfile "^4.0.0"
+    graceful-fs "^4.1.2"
+    jsonfile "^3.0.0"
    universalify "^0.1.0"

 fs-readdir-recursive@^1.0.0:
@@ -1060,11 +1024,6 @@ fsevents@^1.0.0:
    nan "^2.3.0"
    node-pre-gyp "^0.6.29"

-fsevents@^2.0.6:
-  version "2.0.7"
-  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.0.7.tgz#382c9b443c6cbac4c57187cdda23aa3bf1ccfc2a"
-  integrity sha512-a7YT0SV3RB+DjYcppwVDLtn13UQnmg0SWZS7ezZD0UjnLwXmy8Zm21GMVGLaFGimIqcvyMQaOJBrop8MyOp1kQ==
-
 fstream-ignore@~1.0.5:
  version "1.0.5"
  resolved "https://registry.yarnpkg.com/fstream-ignore/-/fstream-ignore-1.0.5.tgz#9c31dae34767018fe1d249b24dada67d092da105"
@@ -1119,10 +1078,13 @@ generate-object-property@^1.1.0:
  dependencies:
    is-property "^1.0.0"

-get-caller-file@^2.0.1:
-  version "2.0.5"
-  resolved "https://registry.yarnpkg.com/get-caller-file/-/get-caller-file-2.0.5.tgz#4f94412a82db32f36e3b0b9741f8a97feb031f7e"
-  integrity sha512-DyFP3BM/3YHTQOCUL/w0OZHR0lpKeGrxotcHWcqNEdnltqFwXVfhEBQ94eIo34AfQpo0rGki4cyIiftY06h2Fg==
+get-caller-file@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/get-caller-file/-/get-caller-file-1.0.2.tgz#f702e63127e7e231c160a80c1554acb70d5047e5"
+
+get-stream@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-3.0.0.tgz#8e943d1358dc37555054ecbe2edb05aa174ede14"

 getpass@^0.1.1:
  version "0.1.6"
@@ -1143,13 +1105,6 @@ glob-parent@^2.0.0:
  dependencies:
    is-glob "^2.0.0"

-glob-parent@^5.0.0:
-  version "5.0.0"
-  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.0.0.tgz#1dc99f0f39b006d3e92c2c284068382f0c20e954"
-  integrity sha512-Z2RwiujPRGluePM6j699ktJYxmPpJKCfpGA13jz2hmFZC7gKetzrWvg5KN3+OsIFmydGyZ1AVwERCq1w/ZZwRg==
-  dependencies:
-    is-glob "^4.0.1"
-
 glob@7.0.5:
  version "7.0.5"
  resolved "https://registry.yarnpkg.com/glob/-/glob-7.0.5.tgz#b4202a69099bbb4d292a7c1b95b6682b67ebdc95"
@@ -1180,11 +1135,6 @@ graceful-fs@^4.1.2, graceful-fs@^4.1.4, graceful-fs@^4.1.6:
  version "4.1.11"
  resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.1.11.tgz#0e8bdfe4d1ddb8854d64e04ea7c00e2a026e5658"

-graceful-fs@^4.2.0:
-  version "4.2.0"
-  resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.2.0.tgz#8d8fdc73977cb04104721cb53666c1ca64cd328b"
-  integrity sha512-jpSvDPV4Cq/bgtpndIWbI5hmYxhQGHPC4d4cqBPb4DLniCfhJokdXhwhaDuLBGLQdvvRum/UiX6ECVIPvDXqdg==
-
 "graceful-readlink@>= 1.0.0":
  version "1.0.1"
  resolved "https://registry.yarnpkg.com/graceful-readlink/-/graceful-readlink-1.0.1.tgz#4cafad76bc62f02fa039b2f94e9a3dd3a391a725"
@@ -1236,6 +1186,10 @@ home-or-tmp@^2.0.0:
    os-homedir "^1.0.0"
    os-tmpdir "^1.0.1"

+hosted-git-info@^2.1.4:
+  version "2.5.0"
+  resolved "https://registry.yarnpkg.com/hosted-git-info/-/hosted-git-info-2.5.0.tgz#6d60e34b3abbc8313062c3b798ef8d901a07af3c"
+
 http-signature@~1.1.0:
  version "1.1.1"
  resolved "https://registry.yarnpkg.com/http-signature/-/http-signature-1.1.1.tgz#df72e267066cd0ac67fb76adf8e134a8fbcf91bf"
@@ -1265,23 +1219,30 @@ invariant@^2.2.0, invariant@^2.2.2:
  dependencies:
    loose-envify "^1.0.0"

+invert-kv@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/invert-kv/-/invert-kv-1.0.0.tgz#104a8e4aaca6d3d8cd157a8ef8bfab2d7a3ffdb6"
+
+is-arrayish@^0.2.1:
+  version "0.2.1"
+  resolved "https://registry.yarnpkg.com/is-arrayish/-/is-arrayish-0.2.1.tgz#77c99840527aa8ecb1a8ba697b80645a7a926a9d"
+
 is-binary-path@^1.0.0:
  version "1.0.1"
  resolved "https://registry.yarnpkg.com/is-binary-path/-/is-binary-path-1.0.1.tgz#75f16642b480f187a711c814161fd3a4a7655898"
  dependencies:
    binary-extensions "^1.0.0"

-is-binary-path@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/is-binary-path/-/is-binary-path-2.1.0.tgz#ea1f7f3b80f064236e83470f86c09c254fb45b09"
-  integrity sha512-ZMERYes6pDydyuGidse7OsHxtbI7WVeUEozgR/g7rd0xUimYNlvZRE/K2MgZTjWy725IfelLeVcEM97mmtRGXw==
-  dependencies:
-    binary-extensions "^2.0.0"
-
 is-buffer@^1.0.2:
  version "1.1.4"
  resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.4.tgz#cfc86ccd5dc5a52fa80489111c6920c457e2d98b"

+is-builtin-module@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/is-builtin-module/-/is-builtin-module-1.0.0.tgz#540572d34f7ac3119f8f76c30cbc1b1e037affbe"
+  dependencies:
+    builtin-modules "^1.0.0"
+
 is-dotfile@^1.0.0:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/is-dotfile/-/is-dotfile-1.0.2.tgz#2c132383f39199f8edc268ca01b9b007d205cc4d"
@@ -1300,11 +1261,6 @@ is-extglob@^1.0.0:
  version "1.0.0"
  resolved "https://registry.yarnpkg.com/is-extglob/-/is-extglob-1.0.0.tgz#ac468177c4943405a092fc8f29760c6ffc6206c0"

-is-extglob@^2.1.1:
-  version "2.1.1"
-  resolved "https://registry.yarnpkg.com/is-extglob/-/is-extglob-2.1.1.tgz#a88c02535791f02ed37c76a1b9ea9773c833f8c2"
-  integrity sha1-qIwCU1eR8C7TfHahueqXc8gz+MI=
-
 is-finite@^1.0.0:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/is-finite/-/is-finite-1.0.2.tgz#cc6677695602be550ef11e8b4aa6305342b6d0aa"
@@ -1327,13 +1283,6 @@ is-glob@^2.0.0, is-glob@^2.0.1:
  dependencies:
    is-extglob "^1.0.0"

-is-glob@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/is-glob/-/is-glob-4.0.1.tgz#7567dbe9f2f5e2467bc77ab83c4a29482407a5dc"
-  integrity sha512-5G0tKtBTFImOqDnLB2hG6Bp2qcKEFduo4tZu9MT/H6NQv/ghhy30o55ufafxJ/LdH79LLs2Kfrn85TLKyA7BUg==
-  dependencies:
-    is-extglob "^2.1.1"
-
 is-my-json-valid@^2.12.4:
  version "2.15.0"
  resolved "https://registry.yarnpkg.com/is-my-json-valid/-/is-my-json-valid-2.15.0.tgz#936edda3ca3c211fd98f3b2d3e08da43f7b2915b"
@@ -1349,11 +1298,6 @@ is-number@^2.0.2, is-number@^2.1.0:
  dependencies:
    kind-of "^3.0.2"

-is-number@^7.0.0:
-  version "7.0.0"
-  resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
-  integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
-
 is-posix-bracket@^0.1.0:
  version "0.1.1"
  resolved "https://registry.yarnpkg.com/is-posix-bracket/-/is-posix-bracket-0.1.1.tgz#3334dc79774368e92f016e6fbc0a88f5cd6e6bc4"
@@ -1366,6 +1310,10 @@ is-property@^1.0.0:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/is-property/-/is-property-1.0.2.tgz#57fe1c4e48474edd65b09911f26b1cd4095dda84"

+is-stream@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/is-stream/-/is-stream-1.1.0.tgz#12d4a3dd4e68e0b79ceb8dbc84173ae80d91ca44"
+
 is-typedarray@~1.0.0:
  version "1.0.0"
  resolved "https://registry.yarnpkg.com/is-typedarray/-/is-typedarray-1.0.0.tgz#e479c80858df0c1b11ddda6940f96011fcda4a9a"
@@ -1434,10 +1382,9 @@ json5@^0.5.0:
  version "0.5.1"
  resolved "https://registry.yarnpkg.com/json5/-/json5-0.5.1.tgz#1eade7acc012034ad84e2396767ead9fa5495821"

-jsonfile@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-4.0.0.tgz#8771aae0799b64076b76640fca058f9c10e33ecb"
-  integrity sha1-h3Gq4HmbZAdrdmQPygWPnBDjPss=
+jsonfile@^3.0.0:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-3.0.1.tgz#a5ecc6f65f53f662c4415c7675a0331d0992ec66"
  optionalDependencies:
    graceful-fs "^4.1.6"

@@ -1465,12 +1412,26 @@ kind-of@^3.0.2:
  dependencies:
    is-buffer "^1.0.2"

-locate-path@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/locate-path/-/locate-path-3.0.0.tgz#dbec3b3ab759758071b58fe59fc41871af21400e"
-  integrity sha512-7AO748wWnIhNqAuaty2ZWHkQHRSNfPVIsPIfwEOWO22AmaoVrWavlOcMR5nzTLNYvp36X220/maaRsrec1G65A==
+lcid@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/lcid/-/lcid-1.0.0.tgz#308accafa0bc483a3867b4b6f2b9506251d1b835"
  dependencies:
-    p-locate "^3.0.0"
+    invert-kv "^1.0.0"
+
+load-json-file@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/load-json-file/-/load-json-file-2.0.0.tgz#7947e42149af80d696cbf797bcaabcfe1fe29ca8"
+  dependencies:
+    graceful-fs "^4.1.2"
+    parse-json "^2.2.0"
+    pify "^2.0.0"
+    strip-bom "^3.0.0"
+
+locate-path@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/locate-path/-/locate-path-2.0.0.tgz#2b568b265eec944c6d9c0de9c3dbbbca0354cd8e"
+  dependencies:
+    p-locate "^2.0.0"
    path-exists "^3.0.0"

 lodash._baseassign@^3.0.0:
@@ -1541,6 +1502,12 @@ lru-cache@^4.0.1:
    pseudomap "^1.0.2"
    yallist "^2.1.2"

+mem@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/mem/-/mem-1.1.0.tgz#5edd52b485ca1d900fe64895505399a0dfa45f76"
+  dependencies:
+    mimic-fn "^1.0.0"
+
 micromatch@^2.1.5:
  version "2.3.11"
  resolved "https://registry.yarnpkg.com/micromatch/-/micromatch-2.3.11.tgz#86677c97d1720b363431d04d0d15293bd38c1565"
@@ -1569,6 +1536,10 @@ mime-types@^2.1.12, mime-types@~2.1.7:
  dependencies:
    mime-db "~1.25.0"

+mimic-fn@^1.0.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-1.1.0.tgz#e667783d92e89dbd342818b5230b9d62a672ad18"
+
 minimatch@^3.0.0, minimatch@^3.0.2:
  version "3.0.3"
  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.3.tgz#2a4e4090b96b2db06a9d7df01055a62a77c9b774"
@@ -1667,14 +1638,24 @@ node-pre-gyp@^0.6.29:
  dependencies:
    abbrev "1"

+normalize-package-data@^2.3.2:
+  version "2.4.0"
+  resolved "https://registry.yarnpkg.com/normalize-package-data/-/normalize-package-data-2.4.0.tgz#12f95a307d58352075a04907b84ac8be98ac012f"
+  dependencies:
+    hosted-git-info "^2.1.4"
+    is-builtin-module "^1.0.0"
+    semver "2 || 3 || 4 || 5"
+    validate-npm-package-license "^3.0.1"
+
 normalize-path@^2.0.1:
  version "2.0.1"
  resolved "https://registry.yarnpkg.com/normalize-path/-/normalize-path-2.0.1.tgz#47886ac1662760d4261b7d979d241709d3ce3f7a"

-normalize-path@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/normalize-path/-/normalize-path-3.0.0.tgz#0dcd69ff23a1c9b11fd0978316644a0388216a65"
-  integrity sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA==
+npm-run-path@^2.0.0:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/npm-run-path/-/npm-run-path-2.0.2.tgz#35a9232dfa35d7067b4cb2ddf2357b1871536c5f"
+  dependencies:
+    path-key "^2.0.0"

 "npmlog@0 || 1 || 2 || 3 || 4":
  version "4.1.2"
@@ -1729,6 +1710,14 @@ os-homedir@^1.0.0:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-1.0.2.tgz#ffbc4988336e0e833de0c168c7ef152121aa7fb3"

+os-locale@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/os-locale/-/os-locale-2.1.0.tgz#42bc2900a6b5b8bd17376c8e882b65afccf24bf2"
+  dependencies:
+    execa "^0.7.0"
+    lcid "^1.0.0"
+    mem "^1.1.0"
+
 os-tmpdir@^1.0.0, os-tmpdir@^1.0.1:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/os-tmpdir/-/os-tmpdir-1.0.2.tgz#bbe67406c79aa85c5cfec766fe5734555dfa1274"
@@ -1748,24 +1737,25 @@ output-file-sync@^1.1.0:
    mkdirp "^0.5.1"
    object-assign "^4.1.0"

-p-limit@^2.0.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-2.2.0.tgz#417c9941e6027a9abcba5092dd2904e255b5fbc2"
-  integrity sha512-pZbTJpoUsCzV48Mc9Nh51VbwO0X9cuPFE8gYwx9BTCt9SF8/b7Zljd2fVgOxhIF/HDTKgpVzs+GPhyKfjLLFRQ==
-  dependencies:
-    p-try "^2.0.0"
+p-finally@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/p-finally/-/p-finally-1.0.0.tgz#3fbcfb15b899a44123b34b6dcc18b724336a2cae"

-p-locate@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/p-locate/-/p-locate-3.0.0.tgz#322d69a05c0264b25997d9f40cd8a891ab0064a4"
-  integrity sha512-x+12w/To+4GFfgJhBEpiDcLozRJGegY+Ei7/z0tSLkMmxGZNybVMSfWj9aJn8Z5Fc7dBUNJOOVgPv2H7IwulSQ==
+p-limit@^1.1.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-1.2.0.tgz#0e92b6bedcb59f022c13d0f1949dc82d15909f1c"
  dependencies:
-    p-limit "^2.0.0"
+    p-try "^1.0.0"

-p-try@^2.0.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/p-try/-/p-try-2.2.0.tgz#cb2868540e313d61de58fafbe35ce9004d5540e6"
-  integrity sha512-R4nPAVTAU0B9D35/Gk3uJf/7XYbQcyohSKdvAxIRSNghFl4e71hVoGnBNQz9cWaXxO2I10KTC+3jMdvvoKw6dQ==
+p-locate@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/p-locate/-/p-locate-2.0.0.tgz#20a0103b222a70c8fd39cc2e580680f3dde5ec43"
+  dependencies:
+    p-limit "^1.1.0"
+
+p-try@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/p-try/-/p-try-1.0.0.tgz#cbc79cdbaf8fd4228e13f621f2b1a237c1b207b3"

 parse-glob@^3.0.4:
  version "3.0.4"
@@ -1776,6 +1766,12 @@ parse-glob@^3.0.4:
    is-extglob "^1.0.0"
    is-glob "^2.0.0"

+parse-json@^2.2.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/parse-json/-/parse-json-2.2.0.tgz#f480f40434ef80741f8469099f8dea18f55a4dc9"
+  dependencies:
+    error-ex "^1.2.0"
+
 path-exists@^3.0.0:
  version "3.0.0"
  resolved "https://registry.yarnpkg.com/path-exists/-/path-exists-3.0.0.tgz#ce0ebeaa5f78cb18925ea7d810d7b59b010fd515"
@@ -1784,10 +1780,19 @@ path-is-absolute@^1.0.0:
  version "1.0.1"
  resolved "https://registry.yarnpkg.com/path-is-absolute/-/path-is-absolute-1.0.1.tgz#174b9268735534ffbc7ace6bf53a5a9e1b5c5f5f"

-picomatch@^2.0.4:
-  version "2.0.7"
-  resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.0.7.tgz#514169d8c7cd0bdbeecc8a2609e34a7163de69f6"
-  integrity sha512-oLHIdio3tZ0qH76NybpeneBhYVj0QFTfXEFTc/B3zKQspYfYYkWYgFsmzo+4kvId/bQRcNkVeguI3y+CD22BtA==
+path-key@^2.0.0:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/path-key/-/path-key-2.0.1.tgz#411cadb574c5a140d3a4b1910d40d80cc9f40b40"
+
+path-type@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/path-type/-/path-type-2.0.0.tgz#f012ccb8415b7096fc2daa1054c3d72389594c73"
+  dependencies:
+    pify "^2.0.0"
+
+pify@^2.0.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"

 pinkie-promise@^2.0.0:
  version "2.0.1"
@@ -1839,6 +1844,21 @@ rc@~1.1.6:
    minimist "^1.2.0"
    strip-json-comments "~1.0.4"

+read-pkg-up@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/read-pkg-up/-/read-pkg-up-2.0.0.tgz#6b72a8048984e0c41e79510fd5e9fa99b3b549be"
+  dependencies:
+    find-up "^2.0.0"
+    read-pkg "^2.0.0"
+
+read-pkg@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/read-pkg/-/read-pkg-2.0.0.tgz#8ef1c0623c6a6db0dc6713c4bfac46332b2368f8"
+  dependencies:
+    load-json-file "^2.0.0"
+    normalize-package-data "^2.3.2"
+    path-type "^2.0.0"
+
 "readable-stream@^2.0.0 || ^1.1.13", readable-stream@^2.0.2:
  version "2.2.2"
  resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.2.2.tgz#a9e6fec3c7dda85f8bb1b3ba7028604556fc825e"
@@ -1872,13 +1892,6 @@ readdirp@^2.0.0:
    readable-stream "^2.0.2"
    set-immediate-shim "^1.0.1"

-readdirp@^3.1.1:
-  version "3.1.1"
-  resolved "https://registry.yarnpkg.com/readdirp/-/readdirp-3.1.1.tgz#b158123ac343c8b0f31d65680269cc0fc1025db1"
-  integrity sha512-XXdSXZrQuvqoETj50+JAitxz1UPdt5dupjT6T5nVB+WvjMv2XKYj+s7hPeAVCXvmJrL36O4YYyWlIC3an2ePiQ==
-  dependencies:
-    picomatch "^2.0.4"
-
 regenerate@^1.2.1:
  version "1.3.3"
  resolved "https://registry.yarnpkg.com/regenerate/-/regenerate-1.3.3.tgz#0c336d3980553d755c39b586ae3b20aa49c82b7f"
@@ -1967,10 +1980,9 @@ require-directory@^2.1.1:
  version "2.1.1"
  resolved "https://registry.yarnpkg.com/require-directory/-/require-directory-2.1.1.tgz#8c64ad5fd30dab1c976e2344ffe7f792a6a6df42"

-require-main-filename@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/require-main-filename/-/require-main-filename-2.0.0.tgz#d0b329ecc7cc0f61649f62215be69af54aa8989b"
-  integrity sha512-NKN5kMDylKuldxYLSUfrbo5Tuzh4hd+2E8NPPX02mZtn1VuREQToYe/ZdlJy+J3uCpfaiGF05e7B8W0iXbQHmg==
+require-main-filename@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/require-main-filename/-/require-main-filename-1.0.1.tgz#97f717b69d48784f5f526a6c5aa8ffdda055a4d1"

 resolve@~1.1.7:
  version "1.1.7"
@@ -1982,6 +1994,10 @@ rimraf@2, rimraf@~2.5.1, rimraf@~2.5.4:
  dependencies:
    glob "^7.0.5"

+"semver@2 || 3 || 4 || 5":
+  version "5.5.0"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
+
 semver@~5.3.0:
  version "5.3.0"
  resolved "https://registry.yarnpkg.com/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
@@ -2028,6 +2044,20 @@ source-map@^0.5.0, source-map@^0.5.6:
  version "0.5.6"
  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.6.tgz#75ce38f52bf0733c5a7f0c118d81334a2bb5f412"

+spdx-correct@~1.0.0:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/spdx-correct/-/spdx-correct-1.0.2.tgz#4b3073d933ff51f3912f03ac5519498a4150db40"
+  dependencies:
+    spdx-license-ids "^1.0.2"
+
+spdx-expression-parse@~1.0.0:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/spdx-expression-parse/-/spdx-expression-parse-1.0.4.tgz#9bdf2f20e1f40ed447fbe273266191fced51626c"
+
+spdx-license-ids@^1.0.2:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/spdx-license-ids/-/spdx-license-ids-1.2.2.tgz#c9df7a3424594ade6bd11900d596696dc06bac57"
+
 sshpk@^1.7.0:
  version "1.10.1"
  resolved "https://registry.yarnpkg.com/sshpk/-/sshpk-1.10.1.tgz#30e1a5d329244974a1af61511339d595af6638b0"
@@ -2051,14 +2081,12 @@ string-width@^1.0.1:
    is-fullwidth-code-point "^1.0.0"
    strip-ansi "^3.0.0"

-string-width@^3.0.0, string-width@^3.1.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/string-width/-/string-width-3.1.0.tgz#22767be21b62af1081574306f69ac51b62203961"
-  integrity sha512-vafcv6KjVZKSgz06oM/H6GDBrAtz8vdhQakGjFIvNrHA6y3HCF1CInLy+QLq8dTJPQ1b+KDUqDFctkdRW44e1w==
+string-width@^2.0.0:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/string-width/-/string-width-2.1.1.tgz#ab93f27a8dc13d28cac815c462143a6d9012ae9e"
  dependencies:
-    emoji-regex "^7.0.1"
    is-fullwidth-code-point "^2.0.0"
-    strip-ansi "^5.1.0"
+    strip-ansi "^4.0.0"

 string_decoder@~0.10.x:
  version "0.10.31"
@@ -2074,12 +2102,19 @@ strip-ansi@^3.0.0, strip-ansi@^3.0.1:
  dependencies:
    ansi-regex "^2.0.0"

-strip-ansi@^5.0.0, strip-ansi@^5.1.0, strip-ansi@^5.2.0:
-  version "5.2.0"
-  resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-5.2.0.tgz#8c9a536feb6afc962bdfa5b104a5091c1ad9c0ae"
-  integrity sha512-DuRs1gKbBqsMKIZlrffwlug8MHkcnpjs5VPmL1PAh+mA30U0DTotfDZ0d2UUsXpPmPmMMJ6W773MaA3J+lbiWA==
+strip-ansi@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-4.0.0.tgz#a8479022eb1ac368a871389b635262c505ee368f"
  dependencies:
-    ansi-regex "^4.1.0"
+    ansi-regex "^3.0.0"
+
+strip-bom@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/strip-bom/-/strip-bom-3.0.0.tgz#2334c18e9c759f7bdd56fdef7e9ae3d588e68ed3"
+
+strip-eof@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/strip-eof/-/strip-eof-1.0.0.tgz#bb43ff5598a6eb05d89b59fcd129c983313606bf"

 strip-json-comments@~1.0.4:
  version "1.0.4"
@@ -2128,13 +2163,6 @@ to-fast-properties@^1.0.1, to-fast-properties@^1.0.3:
  version "1.0.3"
  resolved "https://registry.yarnpkg.com/to-fast-properties/-/to-fast-properties-1.0.3.tgz#b83571fa4d8c25b82e231b06e3a3055de4ca1a47"

-to-regex-range@^5.0.1:
-  version "5.0.1"
-  resolved "https://registry.yarnpkg.com/to-regex-range/-/to-regex-range-5.0.1.tgz#1648c44aae7c8d988a326018ed72f5b4dd0392e4"
-  integrity sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==
-  dependencies:
-    is-number "^7.0.0"
-
 tough-cookie@~2.3.0:
  version "2.3.2"
  resolved "https://registry.yarnpkg.com/tough-cookie/-/tough-cookie-2.3.2.tgz#f081f76e4c85720e6c37a5faced737150d84072a"
@@ -2179,6 +2207,13 @@ v8flags@^2.0.10:
  dependencies:
    user-home "^1.1.1"

+validate-npm-package-license@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/validate-npm-package-license/-/validate-npm-package-license-3.0.1.tgz#2804babe712ad3379459acfbe24746ab2c303fbc"
+  dependencies:
+    spdx-correct "~1.0.0"
+    spdx-expression-parse "~1.0.0"
+
 verror@1.3.6:
  version "1.3.6"
  resolved "https://registry.yarnpkg.com/verror/-/verror-1.3.6.tgz#cff5df12946d297d2baaefaa2689e25be01c005c"
@@ -2201,14 +2236,12 @@ wide-align@^1.1.0:
  dependencies:
    string-width "^1.0.1"

-wrap-ansi@^5.1.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-5.1.0.tgz#1fd1f67235d5b6d0fee781056001bfb694c03b09"
-  integrity sha512-QC1/iN/2/RPVJ5jYK8BGttj5z83LmSKmvbvrXPNCLZSEb32KKVDJDl/MOt2N01qU2H/FkzEa9PKto1BqDjtd7Q==
+wrap-ansi@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-2.1.0.tgz#d8fc3d284dd05794fe84973caecdd1cf824fdd85"
  dependencies:
-    ansi-styles "^3.2.0"
-    string-width "^3.0.0"
-    strip-ansi "^5.0.0"
+    string-width "^1.0.1"
+    strip-ansi "^3.0.1"

 wrappy@1:
  version "1.0.2"
@@ -2218,35 +2251,34 @@ xtend@^4.0.0:
  version "4.0.1"
  resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"

-y18n@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/y18n/-/y18n-4.0.0.tgz#95ef94f85ecc81d007c264e190a120f0a3c8566b"
-  integrity sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w==
+y18n@^3.2.1:
+  version "3.2.1"
+  resolved "https://registry.yarnpkg.com/y18n/-/y18n-3.2.1.tgz#6d15fba884c08679c0d77e88e7759e811e07fa41"

 yallist@^2.1.2:
  version "2.1.2"
  resolved "https://registry.yarnpkg.com/yallist/-/yallist-2.1.2.tgz#1c11f9218f076089a47dd512f93c6699a6a81d52"

-yargs-parser@^13.1.1:
-  version "13.1.1"
-  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.1.tgz#d26058532aa06d365fe091f6a1fc06b2f7e5eca0"
-  integrity sha512-oVAVsHz6uFrg3XQheFII8ESO2ssAf9luWuAd6Wexsu4F3OtIW0o8IribPXYrD4WC24LWtPrJlGy87y5udK+dxQ==
+yargs-parser@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-7.0.0.tgz#8d0ac42f16ea55debd332caf4c4038b3e3f5dfd9"
  dependencies:
-    camelcase "^5.0.0"
-    decamelize "^1.2.0"
+    camelcase "^4.1.0"

-yargs@^13.1.0:
-  version "13.3.0"
-  resolved "https://registry.yarnpkg.com/yargs/-/yargs-13.3.0.tgz#4c657a55e07e5f2cf947f8a366567c04a0dedc83"
-  integrity sha512-2eehun/8ALW8TLoIl7MVaRUrg+yCnenu8B4kBlRxj3GJGDKU1Og7sMXPNm1BYyM1DOJmTZ4YeN/Nwxv+8XJsUA==
+yargs@^8.0.2:
+  version "8.0.2"
+  resolved "https://registry.yarnpkg.com/yargs/-/yargs-8.0.2.tgz#6299a9055b1cefc969ff7e79c1d918dceb22c360"
  dependencies:
-    cliui "^5.0.0"
-    find-up "^3.0.0"
-    get-caller-file "^2.0.1"
+    camelcase "^4.1.0"
+    cliui "^3.2.0"
+    decamelize "^1.1.1"
+    get-caller-file "^1.0.1"
+    os-locale "^2.0.0"
+    read-pkg-up "^2.0.0"
    require-directory "^2.1.1"
-    require-main-filename "^2.0.0"
+    require-main-filename "^1.0.1"
    set-blocking "^2.0.0"
-    string-width "^3.0.0"
+    string-width "^2.0.0"
    which-module "^2.0.0"
-    y18n "^4.0.0"
-    yargs-parser "^13.1.1"
+    y18n "^3.2.1"
+    yargs-parser "^7.0.0"
--- a/lib/fb/BUCK
+++ b/lib/fb/BUCK
@@ -2,7 +2,7 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
-load("//tools/build_defs/oss:yoga_defs.bzl", "ANDROID", "JNI_TARGET", "YOGA_ROOTS", "subdir_glob", "yoga_cxx_library", "yoga_prebuilt_cxx_library")
+load("//tools/build_defs/oss:yoga_defs.bzl", "ANDROID", "FBJNI_JAVA_TARGET", "JNI_TARGET", "YOGA_ROOTS", "subdir_glob", "yoga_cxx_library", "yoga_prebuilt_cxx_library")

 yoga_prebuilt_cxx_library(
    name = "ndklog",
@@ -32,14 +32,13 @@ yoga_cxx_library(
        "-Wall",
        "-Werror",
        "-Wno-unused-parameter",
-        "-Wno-unused-variable",
        "-std=c++11",
    ],
    platforms = (ANDROID,),
-    soname = "libfbjni.$(ext)",
    visibility = ["PUBLIC"],
    deps = [
        ":ndklog",
+        FBJNI_JAVA_TARGET,
        JNI_TARGET,
    ],
 )
--- a/lib/fb/src/main/cpp/CMakeLists.txt
+++ b/lib/fb/src/main/cpp/CMakeLists.txt
@@ -20,7 +20,6 @@ add_compile_options(
 file(GLOB fb_SRC
    *.cpp
    jni/*.cpp
-    jni/detail/*.cpp
    lyra/*.cpp)

 add_library(fb SHARED
--- a/lib/fb/src/main/cpp/assert.cpp
+++ b/lib/fb/src/main/cpp/assert.cpp
@@ -0,0 +1,38 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include <cstdarg>
+#include <stdio.h>
+
+#include <fb/assert.h>
+#include <fb/log.h>
+
+namespace facebook {
+
+#define ASSERT_BUF_SIZE 4096
+static char sAssertBuf[ASSERT_BUF_SIZE];
+static AssertHandler gAssertHandler;
+
+void assertInternal(const char* formatstr ...) {
+    va_list va_args;
+    va_start(va_args, formatstr);
+    vsnprintf(sAssertBuf, sizeof(sAssertBuf), formatstr, va_args);
+    va_end(va_args);
+    if (gAssertHandler != NULL) {
+        gAssertHandler(sAssertBuf);
+    }
+    FBLOG(LOG_FATAL, "fbassert", "%s", sAssertBuf);
+    // crash at this specific address so that we can find our crashes easier
+    *(int*)0xdeadb00c = 0;
+    // let the compiler know we won't reach the end of the function
+     __builtin_unreachable();
+}
+
+void setAssertHandler(AssertHandler assertHandler) {
+    gAssertHandler = assertHandler;
+}
+
+} // namespace facebook
--- a/lib/fb/src/main/cpp/include/fb/ALog.h
+++ b/lib/fb/src/main/cpp/include/fb/ALog.h
@@ -0,0 +1,80 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+/** @file ALog.h
+ *
+ *  Very simple android only logging. Define LOG_TAG to enable the macros.
+ */
+
+#pragma once
+
+#ifdef __ANDROID__
+
+#include <android/log.h>
+
+namespace facebook {
+namespace alog {
+
+template<typename... ARGS>
+inline void log(int level, const char* tag, const char* msg, ARGS... args) noexcept {
+  __android_log_print(level, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void log(int level, const char* tag, const char* msg) noexcept {
+  __android_log_write(level, tag, msg);
+}
+
+template<typename... ARGS>
+inline void logv(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_VERBOSE, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void logd(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_DEBUG, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void logi(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_INFO, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void logw(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_WARN, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void loge(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_ERROR, tag, msg, args...);
+}
+
+template<typename... ARGS>
+inline void logf(const char* tag, const char* msg, ARGS... args) noexcept {
+  log(ANDROID_LOG_FATAL, tag, msg, args...);
+}
+
+
+#ifdef LOG_TAG
+# define ALOGV(...) ::facebook::alog::logv(LOG_TAG, __VA_ARGS__)
+# define ALOGD(...) ::facebook::alog::logd(LOG_TAG, __VA_ARGS__)
+# define ALOGI(...) ::facebook::alog::logi(LOG_TAG, __VA_ARGS__)
+# define ALOGW(...) ::facebook::alog::logw(LOG_TAG, __VA_ARGS__)
+# define ALOGE(...) ::facebook::alog::loge(LOG_TAG, __VA_ARGS__)
+# define ALOGF(...) ::facebook::alog::logf(LOG_TAG, __VA_ARGS__)
+#endif
+
+}}
+
+#else
+# define ALOGV(...) ((void)0)
+# define ALOGD(...) ((void)0)
+# define ALOGI(...) ((void)0)
+# define ALOGW(...) ((void)0)
+# define ALOGE(...) ((void)0)
+# define ALOGF(...) ((void)0)
+#endif
--- a/lib/fb/src/main/cpp/include/fb/Countable.h
+++ b/lib/fb/src/main/cpp/include/fb/Countable.h
@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <atomic>
+#include <fb/assert.h>
+#include <fb/noncopyable.h>
+#include <fb/nonmovable.h>
+#include <fb/RefPtr.h>
+
+namespace facebook {
+
+class Countable : public noncopyable, public nonmovable {
+public:
+  // RefPtr expects refcount to start at 0
+  Countable() : m_refcount(0) {}
+  virtual ~Countable()
+  {
+    FBASSERT(m_refcount == 0);
+  }
+
+private:
+  void ref() {
+    ++m_refcount;
+  }
+
+  void unref() {
+    if (0 == --m_refcount) {
+      delete this;
+    }
+  }
+
+  bool hasOnlyOneRef() const {
+    return m_refcount == 1;
+  }
+
+  template <typename T> friend class RefPtr;
+  std::atomic<int> m_refcount;
+};
+
+}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Environment.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Environment.h
@@ -9,69 +9,24 @@
 #include <string>
 #include <jni.h>

+#include <fb/visibility.h>

 namespace facebook {
 namespace jni {

 // Keeps a thread-local reference to the current thread's JNIEnv.
 struct Environment {
-  // Throws a std::runtime_error if this thread isn't attached to the JVM
-  // TODO(T6594868) Benchmark against raw JNI access
-  static JNIEnv* current();
+  // May be null if this thread isn't attached to the JVM
+  FBEXPORT static JNIEnv* current();
  static void initialize(JavaVM* vm);

  // There are subtle issues with calling the next functions directly. It is
  // much better to always use a ThreadScope to manage attaching/detaching for
  // you.
-  static JNIEnv* ensureCurrentThreadIsAttached();
+  FBEXPORT static JNIEnv* ensureCurrentThreadIsAttached();
+  FBEXPORT static void detachCurrentThread();
 };

-namespace detail {
-
-// This will return null the thread isn't attached to the VM, or if
-// fbjni has never been initialized with a VM at all.  You probably
-// shouldn't be using this.
-JNIEnv* currentOrNull();
-
-/**
- * If there's thread-local data, it's a pointer to one of these.  The
- * instance is a member of JniEnvCacher or ThreadScope, and lives on
- * the stack.
- */
-struct TLData {
-  // This is modified only by JniEnvCacher, and is guaranteed to be
-  // valid if set, and refer to an env which originated from a JNI
-  // call into C++.
-  JNIEnv* env;
-  // This is modified only by ThreadScope, and is set only if an
-  // instance of ThreadScope which attached is on the stack.
-  bool attached;
-};
-
-/**
- * RAII object which manages a cached JNIEnv* value.  A Value is only
- * cached if it is guaranteed safe, which means when C++ is called
- * from a registered fbjni function.
- */
-class JniEnvCacher {
-public:
-  JniEnvCacher(JNIEnv* env);
-  JniEnvCacher(JniEnvCacher&) = delete;
-  JniEnvCacher(JniEnvCacher&&) = default;
-  JniEnvCacher& operator=(JniEnvCacher&) = delete;
-  JniEnvCacher& operator=(JniEnvCacher&&) = delete;
-  ~JniEnvCacher();
-
-private:
-  // If this flag is set, then, this object needs to clear the cache.
-  bool thisCached_;
-
-  // The thread local pointer may point here.
-  detail::TLData data_;
-};
-
-}
-
 /**
 * RAII Object that attaches a thread to the JVM. Failing to detach from a thread before it
 * exits will cause a crash, as will calling Detach an extra time, and this guard class helps
@@ -93,11 +48,8 @@ private:
 *    class or instance to the new thread; this bypasses the need for the class loader.
 *    (See http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#attach_current_thread)
 *    If you need access to the application's classes, you can use ThreadScope::WithClassLoader.
- *  - If fbjni has never been initialized, there will be no JavaVM object to attach with.
- *    In that case, a std::runtime_error will be thrown.  This is only likely to happen in a
- *    standalone C++ application, or if Environment::initialize is not used.
 */
-class ThreadScope {
+class FBEXPORT ThreadScope {
 public:
  ThreadScope();
  ThreadScope(ThreadScope&) = delete;
@@ -115,14 +67,8 @@ class ThreadScope {
  static void WithClassLoader(std::function<void()>&& runnable);

  static void OnLoad();
-
 private:
-  // If this flag is set, then this object needs to detach.
-  bool thisAttached_;
-
-  // The thread local pointer may point here.
-  detail::TLData data_;
+  bool attachedWithThisScope_;
 };
-
 }
 }
--- a/lib/fb/src/main/cpp/include/fb/ProgramLocation.h
+++ b/lib/fb/src/main/cpp/include/fb/ProgramLocation.h
@@ -0,0 +1,47 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <cstring>
+#include <string>
+#include <sstream>
+
+namespace facebook {
+
+#define FROM_HERE facebook::ProgramLocation(__FUNCTION__, __FILE__, __LINE__)
+
+class ProgramLocation {
+public:
+  ProgramLocation() : m_functionName("Unspecified"), m_fileName("Unspecified"), m_lineNumber(0) {}
+
+  ProgramLocation(const char* functionName, const char* fileName, int line) :
+      m_functionName(functionName),
+      m_fileName(fileName),
+      m_lineNumber(line)
+    {}
+
+  const char* functionName() const { return m_functionName; }
+  const char* fileName() const { return m_fileName; }
+  int lineNumber() const { return m_lineNumber; }
+
+  std::string asFormattedString() const {
+    std::stringstream str;
+    str << "Function " << m_functionName << " in file " << m_fileName << ":" << m_lineNumber;
+    return str.str();
+  }
+
+  bool operator==(const ProgramLocation& other) const {
+    // Assumes that the strings are static
+    return (m_functionName == other.m_functionName) && (m_fileName == other.m_fileName) && m_lineNumber == other.m_lineNumber;
+  }
+
+private:
+  const char* m_functionName;
+  const char* m_fileName;
+  int m_lineNumber;
+};
+
+}
--- a/lib/fb/src/main/cpp/include/fb/RefPtr.h
+++ b/lib/fb/src/main/cpp/include/fb/RefPtr.h
@@ -0,0 +1,271 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <utility>
+#include <fb/assert.h>
+
+namespace facebook {
+
+// Reference counting smart pointer. This is designed to work with the
+// Countable class or other implementations in the future. It is designed in a
+// way to be both efficient and difficult to misuse. Typical usage is very
+// simple once you learn the patterns (and the compiler will help!):
+//
+// By default, the internal pointer is null.
+//   RefPtr<Foo> ref;
+//
+// Object creation requires explicit construction:
+//   RefPtr<Foo> ref = createNew<Foo>(...);
+//
+// Or if the constructor is not public:
+//   RefPtr<Foo> ref = adoptRef(new Foo(...));
+//
+// But you can implicitly create from nullptr:
+//   RefPtr<Foo> maybeRef = cond ? ref : nullptr;
+//
+// Move/Copy Construction/Assignment are straightforward:
+//   RefPtr<Foo> ref2 = ref;
+//   ref = std::move(ref2);
+//
+// Destruction automatically drops the RefPtr's reference as expected.
+//
+// Upcasting is implicit but downcasting requires an explicit cast:
+//   struct Bar : public Foo {};
+//   RefPtr<Bar> barRef = static_cast<RefPtr<Bar>>(ref);
+//   ref = barRef;
+//
+template <class T>
+class RefPtr {
+public:
+  constexpr RefPtr() :
+    m_ptr(nullptr)
+  {}
+
+  // Allow implicit construction from a pointer only from nullptr
+  constexpr RefPtr(std::nullptr_t ptr) :
+    m_ptr(nullptr)
+  {}
+
+  RefPtr(const RefPtr<T>& ref) :
+    m_ptr(ref.m_ptr)
+  {
+    refIfNecessary(m_ptr);
+  }
+
+  // Only allow implicit upcasts. A downcast will result in a compile error
+  // unless you use static_cast (which will end up invoking the explicit
+  // operator below).
+  template <typename U>
+  RefPtr(const RefPtr<U>& ref, typename std::enable_if<std::is_base_of<T,U>::value, U>::type* = nullptr) :
+    m_ptr(ref.get())
+  {
+    refIfNecessary(m_ptr);
+  }
+
+  RefPtr(RefPtr<T>&& ref) :
+    m_ptr(nullptr)
+  {
+    *this = std::move(ref);
+  }
+
+  // Only allow implicit upcasts. A downcast will result in a compile error
+  // unless you use static_cast (which will end up invoking the explicit
+  // operator below).
+  template <typename U>
+  RefPtr(RefPtr<U>&& ref, typename std::enable_if<std::is_base_of<T,U>::value, U>::type* = nullptr) :
+    m_ptr(nullptr)
+  {
+    *this = std::move(ref);
+  }
+
+  ~RefPtr() {
+    unrefIfNecessary(m_ptr);
+    m_ptr = nullptr;
+  }
+
+  RefPtr<T>& operator=(const RefPtr<T>& ref) {
+    if (m_ptr != ref.m_ptr) {
+      unrefIfNecessary(m_ptr);
+      m_ptr = ref.m_ptr;
+      refIfNecessary(m_ptr);
+    }
+    return *this;
+  }
+
+  // The STL assumes rvalue references are unique and for simplicity's sake, we
+  // make the same assumption here, that &ref != this.
+  RefPtr<T>& operator=(RefPtr<T>&& ref) {
+    unrefIfNecessary(m_ptr);
+    m_ptr = ref.m_ptr;
+    ref.m_ptr = nullptr;
+    return *this;
+  }
+
+  template <typename U>
+  RefPtr<T>& operator=(RefPtr<U>&& ref) {
+    unrefIfNecessary(m_ptr);
+    m_ptr = ref.m_ptr;
+    ref.m_ptr = nullptr;
+    return *this;
+  }
+
+  void reset() {
+    unrefIfNecessary(m_ptr);
+    m_ptr = nullptr;
+  }
+
+  T* get() const {
+    return m_ptr;
+  }
+
+  T* operator->() const {
+    return m_ptr;
+  }
+
+  T& operator*() const {
+    return *m_ptr;
+  }
+
+  template <typename U>
+  explicit operator RefPtr<U> () const;
+
+  explicit operator bool() const {
+    return m_ptr ? true : false;
+  }
+
+  bool isTheLastRef() const {
+    FBASSERT(m_ptr);
+    return m_ptr->hasOnlyOneRef();
+  }
+
+  // Creates a strong reference from a raw pointer, assuming that is already
+  // referenced from some other RefPtr. This should be used sparingly.
+  static inline RefPtr<T> assumeAlreadyReffed(T* ptr) {
+    return RefPtr<T>(ptr, ConstructionMode::External);
+  }
+
+  // Creates a strong reference from a raw pointer, assuming that it points to a
+  // freshly-created object. See the documentation for RefPtr for usage.
+  static inline RefPtr<T> adoptRef(T* ptr) {
+    return RefPtr<T>(ptr, ConstructionMode::Adopted);
+  }
+
+private:
+  enum class ConstructionMode {
+    Adopted,
+    External
+  };
+
+  RefPtr(T* ptr, ConstructionMode mode) :
+    m_ptr(ptr)
+  {
+    FBASSERTMSGF(ptr, "Got null pointer in %s construction mode", mode == ConstructionMode::Adopted ? "adopted" : "external");
+    ptr->ref();
+    if (mode == ConstructionMode::Adopted) {
+      FBASSERT(ptr->hasOnlyOneRef());
+    }
+  }
+
+  static inline void refIfNecessary(T* ptr) {
+    if (ptr) {
+      ptr->ref();
+    }
+  }
+  static inline void unrefIfNecessary(T* ptr) {
+    if (ptr) {
+      ptr->unref();
+    }
+  }
+
+  template <typename U> friend class RefPtr;
+
+  T* m_ptr;
+};
+
+// Creates a strong reference from a raw pointer, assuming that is already
+// referenced from some other RefPtr and that it is non-null. This should be
+// used sparingly.
+template <typename T>
+static inline RefPtr<T> assumeAlreadyReffed(T* ptr) {
+  return RefPtr<T>::assumeAlreadyReffed(ptr);
+}
+
+// As above, but tolerant of nullptr.
+template <typename T>
+static inline RefPtr<T> assumeAlreadyReffedOrNull(T* ptr) {
+  return ptr ? RefPtr<T>::assumeAlreadyReffed(ptr) : nullptr;
+}
+
+// Creates a strong reference from a raw pointer, assuming that it points to a
+// freshly-created object. See the documentation for RefPtr for usage.
+template <typename T>
+static inline RefPtr<T> adoptRef(T* ptr) {
+  return RefPtr<T>::adoptRef(ptr);
+}
+
+template <typename T, typename ...Args>
+static inline RefPtr<T> createNew(Args&&... arguments) {
+  return RefPtr<T>::adoptRef(new T(std::forward<Args>(arguments)...));
+}
+
+template <typename T> template <typename U>
+RefPtr<T>::operator RefPtr<U>() const {
+  static_assert(std::is_base_of<T, U>::value, "Invalid static cast");
+  return assumeAlreadyReffedOrNull<U>(static_cast<U*>(m_ptr));
+}
+
+template <typename T, typename U>
+inline bool operator==(const RefPtr<T>& a, const RefPtr<U>& b) {
+  return a.get() == b.get();
+}
+
+template <typename T, typename U>
+inline bool operator!=(const RefPtr<T>& a, const RefPtr<U>& b) {
+  return a.get() != b.get();
+}
+
+template <typename T, typename U>
+inline bool operator==(const RefPtr<T>& ref, U* ptr) {
+  return ref.get() == ptr;
+}
+
+template <typename T, typename U>
+inline bool operator!=(const RefPtr<T>& ref, U* ptr) {
+  return ref.get() != ptr;
+}
+
+template <typename T, typename U>
+inline bool operator==(U* ptr, const RefPtr<T>& ref) {
+  return ref.get() == ptr;
+}
+
+template <typename T, typename U>
+inline bool operator!=(U* ptr, const RefPtr<T>& ref) {
+  return ref.get() != ptr;
+}
+
+template <typename T>
+inline bool operator==(const RefPtr<T>& ref, std::nullptr_t ptr) {
+  return ref.get() == ptr;
+}
+
+template <typename T>
+inline bool operator!=(const RefPtr<T>& ref, std::nullptr_t ptr) {
+  return ref.get() != ptr;
+}
+
+template <typename T>
+inline bool operator==(std::nullptr_t ptr, const RefPtr<T>& ref) {
+  return ref.get() == ptr;
+}
+
+template <typename T>
+inline bool operator!=(std::nullptr_t ptr, const RefPtr<T>& ref) {
+  return ref.get() != ptr;
+}
+
+}
--- a/lib/fb/src/main/cpp/include/fb/StaticInitialized.h
+++ b/lib/fb/src/main/cpp/include/fb/StaticInitialized.h
@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <fb/assert.h>
+#include <utility>
+
+namespace facebook {
+
+// Class that lets you declare a global but does not add a static constructor
+// to the binary. Eventually I'd like to have this auto-initialize in a
+// multithreaded environment but for now it's easiest just to use manual
+// initialization.
+template <typename T>
+class StaticInitialized {
+public:
+  constexpr StaticInitialized() :
+    m_instance(nullptr)
+  {}
+
+  template <typename ...Args>
+  void initialize(Args&&... arguments) {
+    FBASSERT(!m_instance);
+    m_instance = new T(std::forward<Args>(arguments)...);
+  }
+
+  T* operator->() const {
+    return m_instance;
+  }
+private:
+  T* m_instance;
+};
+
+}
--- a/lib/fb/src/main/cpp/include/fb/ThreadLocal.h
+++ b/lib/fb/src/main/cpp/include/fb/ThreadLocal.h
@@ -0,0 +1,115 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <pthread.h>
+#include <errno.h>
+
+#include <fb/assert.h>
+
+namespace facebook {
+
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+ * A thread-local object is a "global" object within a thread. This is useful
+ * for writing apartment-threaded code, where nothing is actullay shared
+ * between different threads (hence no locking) but those variables are not
+ * on stack in local scope. To use it, just do something like this,
+ *
+ *   ThreadLocal<MyClass> static_object;
+ *     static_object->data_ = ...;
+ *     static_object->doSomething();
+ *
+ *   ThreadLocal<int> static_number;
+ *     int value = *static_number;
+ *
+ * So, syntax-wise it's similar to pointers. T can be primitive types, and if
+ * it's a class, there has to be a default constructor.
+ */
+template<typename T>
+class ThreadLocal {
+public:
+  /**
+   * Constructor that has to be called from a thread-neutral place.
+   */
+  ThreadLocal() :
+    m_key(0),
+    m_cleanup(OnThreadExit) {
+    initialize();
+  }
+
+  /**
+   * As above but with a custom cleanup function
+   */
+  typedef void (*CleanupFunction)(void* obj);
+  explicit ThreadLocal(CleanupFunction cleanup) :
+    m_key(0),
+    m_cleanup(cleanup) {
+    FBASSERT(cleanup);
+    initialize();
+  }
+
+  /**
+   * Access object's member or method through this operator overload.
+   */
+  T *operator->() const {
+    return get();
+  }
+
+  T &operator*() const {
+    return *get();
+  }
+
+  T *get() const {
+    return (T*)pthread_getspecific(m_key);
+  }
+
+  T* release() {
+    T* obj = get();
+    pthread_setspecific(m_key, NULL);
+    return obj;
+  }
+
+  void reset(T* other = NULL) {
+    T* old = (T*)pthread_getspecific(m_key);
+    if (old != other) {
+      FBASSERT(m_cleanup);
+      m_cleanup(old);
+      pthread_setspecific(m_key, other);
+    }
+  }
+
+private:
+  void initialize() {
+    int ret = pthread_key_create(&m_key, m_cleanup);
+    if (ret != 0) {
+      const char *msg = "(unknown error)";
+      switch (ret) {
+      case EAGAIN:
+        msg = "PTHREAD_KEYS_MAX (1024) is exceeded";
+        break;
+      case ENOMEM:
+        msg = "Out-of-memory";
+        break;
+      }
+      (void) msg;
+      FBASSERTMSGF(0, "pthread_key_create failed: %d %s", ret, msg);
+    }
+  }
+
+  static void OnThreadExit(void *obj) {
+    if (NULL != obj) {
+      delete (T*)obj;
+    }
+  }
+
+  pthread_key_t m_key;
+  CleanupFunction m_cleanup;
+};
+
+}
--- a/lib/fb/src/main/cpp/include/fb/assert.h
+++ b/lib/fb/src/main/cpp/include/fb/assert.h
@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#ifndef FBASSERT_H
+#define FBASSERT_H
+
+#include <fb/visibility.h>
+
+namespace facebook {
+#define ENABLE_FBASSERT 1
+
+#if ENABLE_FBASSERT
+#define FBASSERTMSGF(expr, msg, ...) !(expr) ? facebook::assertInternal("Assert (%s:%d): " msg, __FILE__, __LINE__, ##__VA_ARGS__) : (void) 0
+#else
+#define FBASSERTMSGF(expr, msg, ...)
+#endif // ENABLE_FBASSERT
+
+#define FBASSERT(expr) FBASSERTMSGF(expr, "%s", #expr)
+
+#define FBCRASH(msg, ...) facebook::assertInternal("Fatal error (%s:%d): " msg, __FILE__, __LINE__, ##__VA_ARGS__)
+#define FBUNREACHABLE() facebook::assertInternal("This code should be unreachable (%s:%d)", __FILE__, __LINE__)
+
+FBEXPORT void assertInternal(const char* formatstr, ...) __attribute__((noreturn));
+
+// This allows storing the assert message before the current process terminates due to a crash
+typedef void (*AssertHandler)(const char* message);
+void setAssertHandler(AssertHandler assertHandler);
+
+} // namespace facebook
+#endif // FBASSERT_H
--- a/lib/fb/src/main/cpp/include/fb/fbjni.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni.h
@@ -0,0 +1,21 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <jni.h>
+
+#include <fb/Environment.h>
+#include <fb/ALog.h>
+#include <fb/fbjni/Common.h>
+#include <fb/fbjni/Exceptions.h>
+#include <fb/fbjni/ReferenceAllocators.h>
+#include <fb/fbjni/References.h>
+#include <fb/fbjni/Meta.h>
+#include <fb/fbjni/CoreClasses.h>
+#include <fb/fbjni/Iterator.h>
+#include <fb/fbjni/Hybrid.h>
+#include <fb/fbjni/Registration.h>
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Boxed.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Boxed.h
@@ -17,13 +17,13 @@ struct JPrimitive : JavaClass<T> {
  using typename JavaClass<T>::javaobject;
  using JavaClass<T>::javaClassStatic;
  static local_ref<javaobject> valueOf(jprim val) {
-    static const auto cls = javaClassStatic();
-    static const auto method =
+    static auto cls = javaClassStatic();
+    static auto method =
      cls->template getStaticMethod<javaobject(jprim)>("valueOf");
    return method(cls, val);
  }
  jprim value() const {
-    static const auto method =
+    static auto method =
      javaClassStatic()->template getMethod<jprim()>(T::kValueMethod);
    return method(this->self());
  }
@@ -55,20 +55,9 @@ DEFINE_BOXED_PRIMITIVE(double, Double)

 #undef DEFINE_BOXED_PRIMITIVE

-template<typename T>
-inline typename std::enable_if<
-  (std::is_same<T, long long>::value || std::is_same<T, int64_t>::value) && !std::is_same<T, jlong>::value,
-  local_ref<jobject>
->::type autobox(T val) {
-  return JLong::valueOf(val);
-}
-
-struct JVoid : public jni::JavaClass<JVoid> {
-  static auto constexpr kJavaDescriptor = "Ljava/lang/Void;";
-};
-
 inline local_ref<jobject> autobox(alias_ref<jobject> val) {
  return make_local(val);
 }

 }}
+
--- a/lib/fb/src/main/cpp/include/fb/fbjni/ByteBuffer.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/ByteBuffer.h
@@ -6,37 +6,26 @@
 */
 #pragma once

-#include <fbjni/fbjni.h>
+#include <fb/visibility.h>
+
+#include "CoreClasses.h"
+#include "References-forward.h"

 namespace facebook {
 namespace jni {

-class JBuffer : public JavaClass<JBuffer> {
-public:
-  static constexpr const char* kJavaDescriptor = "Ljava/nio/Buffer;";
-
-  void rewind() const;
-  bool isDirect() const;
-  void* getDirectAddress() const;
-  size_t getDirectCapacity() const;
-};
-
 // JNI's NIO support has some awkward preconditions and error reporting. This
 // class provides much more user-friendly access.
-class JByteBuffer : public JavaClass<JByteBuffer, JBuffer> {
+class FBEXPORT JByteBuffer : public JavaClass<JByteBuffer> {
 public:
  static constexpr const char* kJavaDescriptor = "Ljava/nio/ByteBuffer;";

  static local_ref<JByteBuffer> wrapBytes(uint8_t* data, size_t size);
-  static local_ref<JByteBuffer> allocateDirect(jint size);

-  uint8_t* getDirectBytes() const {
-    return static_cast<uint8_t*>(getDirectAddress());
-  }
+  bool isDirect() const;

-  size_t getDirectSize() const {
-    return getDirectCapacity();
-  }
+  uint8_t* getDirectBytes() const;
+  size_t getDirectSize() const;
 };

 }}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Common.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Common.h
@@ -15,6 +15,9 @@

 #include <jni.h>

+#include <fb/visibility.h>
+#include <fb/Environment.h>
+
 #ifdef FBJNI_DEBUG_REFS
 # ifdef __ANDROID__
 #  include <android/log.h>
@@ -39,11 +42,11 @@
 namespace facebook {
 namespace jni {

-void throwPendingJniExceptionAsCppException();
-void throwCppExceptionIf(bool condition);
+FBEXPORT void throwPendingJniExceptionAsCppException();
+FBEXPORT void throwCppExceptionIf(bool condition);

-[[noreturn]] void throwNewJavaException(jthrowable);
-[[noreturn]] void throwNewJavaException(const char* throwableName, const char* msg);
+[[noreturn]] FBEXPORT void throwNewJavaException(jthrowable);
+[[noreturn]] FBEXPORT void throwNewJavaException(const char* throwableName, const char* msg);
 template<typename... Args>
 [[noreturn]] void throwNewJavaException(const char* throwableName, const char* fmt, Args... args);

@@ -62,10 +65,20 @@ template<typename... Args>
 * unhelpful way (typically a segfault) while trying to handle an exception
 * which occurs later.
 */
-jint initialize(JavaVM*, std::function<void()>&&) noexcept;
+FBEXPORT jint initialize(JavaVM*, std::function<void()>&&) noexcept;

 namespace internal {

+/**
+ * Retrieve a pointer the JNI environment of the current thread.
+ *
+ * @pre The current thread must be attached to the VM
+ */
+inline JNIEnv* getEnv() noexcept {
+  // TODO(T6594868) Benchmark against raw JNI access
+  return Environment::current();
+}
+
 // Define to get extremely verbose logging of references and to enable reference stats
 #ifdef FBJNI_DEBUG_REFS
 template<typename... Args>
--- a/lib/fb/src/main/cpp/include/fb/fbjni/Context.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/Context.h
@@ -6,8 +6,8 @@
 */
 #pragma once

-#include <fbjni/fbjni.h>
-#include <fbjni/File.h>
+#include "CoreClasses.h"
+#include "File.h"

 namespace facebook {
 namespace jni {
@@ -18,12 +18,12 @@ class AContext : public JavaClass<AContext> {

  // Define a method that calls into the represented Java class
  local_ref<JFile::javaobject> getCacheDir() {
-    static const auto method = getClass()->getMethod<JFile::javaobject()>("getCacheDir");
+    static auto method = getClass()->getMethod<JFile::javaobject()>("getCacheDir");
    return method(self());
  }

  local_ref<JFile::javaobject> getFilesDir() {
-    static const auto method = getClass()->getMethod<JFile::javaobject()>("getFilesDir");
+    static auto method = getClass()->getMethod<JFile::javaobject()>("getFilesDir");
    return method(self());
  }
 };
--- a/lib/fb/src/main/cpp/include/fbjni/detail/CoreClasses-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/CoreClasses-inl.h
@@ -21,15 +21,15 @@ namespace jni {
 // jobject /////////////////////////////////////////////////////////////////////////////////////////

 inline bool isSameObject(alias_ref<JObject> lhs, alias_ref<JObject> rhs) noexcept {
-  return Environment::current()->IsSameObject(lhs.get(), rhs.get()) != JNI_FALSE;
+  return internal::getEnv()->IsSameObject(lhs.get(), rhs.get()) != JNI_FALSE;
 }

 inline local_ref<JClass> JObject::getClass() const noexcept {
-  return adopt_local(Environment::current()->GetObjectClass(self()));
+  return adopt_local(internal::getEnv()->GetObjectClass(self()));
 }

 inline bool JObject::isInstanceOf(alias_ref<JClass> cls) const noexcept {
-  return Environment::current()->IsInstanceOf(self(), cls.get()) != JNI_FALSE;
+  return internal::getEnv()->IsInstanceOf(self(), cls.get()) != JNI_FALSE;
 }

 template<typename T>
@@ -47,13 +47,8 @@ inline void JObject::setFieldValue(JField<T> field, T value) noexcept {
  field.set(self(), value);
 }

-template<typename T, typename>
-inline void JObject::setFieldValue(JField<T> field, alias_ref<T> value) noexcept {
-  setFieldValue(field, value.get());
-}
-
 inline std::string JObject::toString() const {
-  static const auto method = findClassLocal("java/lang/Object")->getMethod<jstring()>("toString");
+  static auto method = findClassLocal("java/lang/Object")->getMethod<jstring()>("toString");

  return method(self())->toStdString();
 }
@@ -82,13 +77,13 @@ MonitorLock::MonitorLock() noexcept : owned_(nullptr) {}

 MonitorLock::MonitorLock(alias_ref<JObject> object) noexcept
    : owned_(object) {
-  Environment::current()->MonitorEnter(object.get());
+  internal::getEnv()->MonitorEnter(object.get());
 }

 void MonitorLock::reset() noexcept {
  if (owned_) {
-    Environment::current()->MonitorExit(owned_.get());
-    if (Environment::current()->ExceptionCheck()) {
+    internal::getEnv()->MonitorExit(owned_.get());
+    if (internal::getEnv()->ExceptionCheck()) {
      abort(); // Lock mismatch
    }
    owned_ = nullptr;
@@ -131,7 +126,7 @@ namespace detail {
 template<typename JC, typename... Args>
 static local_ref<JC> newInstance(Args... args) {
  static auto cls = JC::javaClassStatic();
-  static const auto constructor = cls->template getConstructor<typename JC::javaobject(Args...)>();
+  static auto constructor = cls->template getConstructor<typename JC::javaobject(Args...)>();
  return cls->newObject(constructor, args...);
 }
 }
@@ -159,18 +154,17 @@ struct NativeMethod {
 };

 inline local_ref<JClass> JClass::getSuperclass() const noexcept {
-  return adopt_local(Environment::current()->GetSuperclass(self()));
+  return adopt_local(internal::getEnv()->GetSuperclass(self()));
 }

 inline void JClass::registerNatives(std::initializer_list<NativeMethod> methods) {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();

  JNINativeMethod jnimethods[methods.size()];
  size_t i = 0;
  for (auto it = methods.begin(); it < methods.end(); ++it, ++i) {
-    // The JNI struct members are unnecessarily non-const.
-    jnimethods[i].name = const_cast<char*>(it->name);
-    jnimethods[i].signature = const_cast<char*>(it->descriptor.c_str());
+    jnimethods[i].name = it->name;
+    jnimethods[i].signature = it->descriptor.c_str();
    jnimethods[i].fnPtr = reinterpret_cast<void*>(it->wrapper);
  }

@@ -179,13 +173,8 @@ inline void JClass::registerNatives(std::initializer_list<NativeMethod> methods)
 }

 inline bool JClass::isAssignableFrom(alias_ref<JClass> other) const noexcept {
-  const auto env = Environment::current();
-  // Ths method has behavior compatible with the
-  // java.lang.Class#isAssignableFrom method.  The order of the
-  // arguments to the JNI IsAssignableFrom C function is "opposite"
-  // from what some might expect, which makes this code look a little
-  // odd, but it is correct.
-  const auto result = env->IsAssignableFrom(other.get(), self());
+  const auto env = internal::getEnv();
+  const auto result = env->IsAssignableFrom(self(), other.get());
  return result;
 }

@@ -209,7 +198,7 @@ template<typename F>
 inline JMethod<F> JClass::getMethod(
    const char* name,
    const char* descriptor) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  const auto method = env->GetMethodID(self(), name, descriptor);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!method);
  return JMethod<F>{method};
@@ -224,7 +213,7 @@ template<typename F>
 inline JStaticMethod<F> JClass::getStaticMethod(
    const char* name,
    const char* descriptor) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  const auto method = env->GetStaticMethodID(self(), name, descriptor);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!method);
  return JStaticMethod<F>{method};
@@ -239,7 +228,7 @@ template<typename F>
 inline JNonvirtualMethod<F> JClass::getNonvirtualMethod(
    const char* name,
    const char* descriptor) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  const auto method = env->GetMethodID(self(), name, descriptor);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!method);
  return JNonvirtualMethod<F>{method};
@@ -255,7 +244,7 @@ template<typename T>
 inline JField<enable_if_t<IsJniScalar<T>(), T>> JClass::getField(
    const char* name,
    const char* descriptor) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  auto field = env->GetFieldID(self(), name, descriptor);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!field);
  return JField<T>{field};
@@ -271,7 +260,7 @@ template<typename T>
 inline JStaticField<enable_if_t<IsJniScalar<T>(), T>> JClass::getStaticField(
    const char* name,
    const char* descriptor) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  auto field = env->GetStaticFieldID(self(), name, descriptor);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!field);
  return JStaticField<T>{field};
@@ -292,16 +281,11 @@ inline void JClass::setStaticFieldValue(JStaticField<T> field, T value) noexcept
  field.set(self(), value);
 }

-template<typename T, typename>
-inline void JClass::setStaticFieldValue(JStaticField<T> field, alias_ref<T> value) noexcept {
-  setStaticFieldValue(field, value.get());
-}
-
 template<typename R, typename... Args>
 inline local_ref<R> JClass::newObject(
    JConstructor<R(Args...)> constructor,
    Args... args) const {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  auto object = env->NewObject(self(), constructor.getId(),
      detail::callToJni(
        detail::Convert<typename std::decay<Args>::type>::toCall(args))...);
@@ -354,11 +338,18 @@ struct Convert<const char*> {
 };
 }

+// jthrowable //////////////////////////////////////////////////////////////////////////////////////
+
+inline local_ref<JThrowable> JThrowable::initCause(alias_ref<JThrowable> cause) {
+  static auto meth = javaClassStatic()->getMethod<javaobject(javaobject)>("initCause");
+  return meth(self(), cause.get());
+}
+
 // jtypeArray //////////////////////////////////////////////////////////////////////////////////////

 namespace detail {
 inline size_t JArray::size() const noexcept {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  return env->GetArrayLength(self());
 }
 }
@@ -418,8 +409,8 @@ std::string JArrayClass<T>::get_instantiated_base_name() {

 template<typename T>
 auto JArrayClass<T>::newArray(size_t size) -> local_ref<javaobject> {
-  static const auto elementClass = findClassStatic(jtype_traits<T>::base_name().c_str());
-  const auto env = Environment::current();
+  static auto elementClass = findClassStatic(jtype_traits<T>::base_name().c_str());
+  const auto env = internal::getEnv();
  auto rawArray = env->NewObjectArray(size, elementClass.get(), nullptr);
  FACEBOOK_JNI_THROW_EXCEPTION_IF(!rawArray);
  return adopt_local(static_cast<javaobject>(rawArray));
@@ -427,13 +418,13 @@ auto JArrayClass<T>::newArray(size_t size) -> local_ref<javaobject> {

 template<typename T>
 inline void JArrayClass<T>::setElement(size_t idx, const T& value) {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  env->SetObjectArrayElement(this->self(), idx, value);
 }

 template<typename T>
 inline local_ref<T> JArrayClass<T>::getElement(size_t idx) {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  auto rawElement = env->GetObjectArrayElement(this->self(), idx);
  return adopt_local(static_cast<T>(rawElement));
 }
@@ -443,16 +434,12 @@ inline detail::ElementProxy<JArrayClass<T>> JArrayClass<T>::operator[](size_t in
  return detail::ElementProxy<JArrayClass<T>>(this, index);
 }

-template<typename T>
-local_ref<typename JArrayClass<T>::javaobject> adopt_local_array(jobjectArray ref) {
-  return adopt_local(static_cast<typename JArrayClass<T>::javaobject>(ref));
-}
-
 // jarray /////////////////////////////////////////////////////////////////////////////////////////

 template <typename JArrayType>
 auto JPrimitiveArray<JArrayType>::getRegion(jsize start, jsize length)
    -> std::unique_ptr<T[]> {
+  using T = typename jtype_traits<JArrayType>::entry_type;
  auto buf = std::unique_ptr<T[]>{new T[length]};
  getRegion(start, length, buf.get());
  return buf;
@@ -523,7 +510,7 @@ class PinnedCriticalAlloc {
      jboolean* isCopy) {
    (void)start;
    (void)length;
-    const auto env = Environment::current();
+    const auto env = internal::getEnv();
    *elements = static_cast<T*>(env->GetPrimitiveArrayCritical(array.get(), isCopy));
    FACEBOOK_JNI_THROW_EXCEPTION_IF(!elements);
    *size = array->size();
@@ -536,7 +523,7 @@ class PinnedCriticalAlloc {
      jint mode) {
    (void)start;
    (void)size;
-    const auto env = Environment::current();
+    const auto env = internal::getEnv();
    env->ReleasePrimitiveArrayCritical(array.get(), elements, mode);
  }
 };
--- a/lib/fb/src/main/cpp/include/fbjni/detail/CoreClasses.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/CoreClasses.h
@@ -20,19 +20,14 @@

 #include <jni.h>

+#include <fb/visibility.h>
+
 namespace facebook {
 namespace jni {

 class JClass;
 class JObject;

-namespace detail {
-
-/// Lookup a class by name.  This should only be used internally.
-jclass findClass(JNIEnv* env, const char* name);
-
-}
-
 /// Lookup a class by name. Note this functions returns an alias_ref that
 /// points to a leaked global reference.  This is appropriate for classes
 /// that are never unloaded (which is any class in an Android app and most
@@ -42,7 +37,7 @@ jclass findClass(JNIEnv* env, const char* name);
 /// in a "static auto" variable, or a static global.
 ///
 /// @return Returns a leaked global reference to the class
-alias_ref<JClass> findClassStatic(const char* name);
+FBEXPORT alias_ref<JClass> findClassStatic(const char* name);

 /// Lookup a class by name. Note this functions returns a local reference,
 /// which means that it must not be stored in a static variable.
@@ -51,12 +46,12 @@ alias_ref<JClass> findClassStatic(const char* name);
 /// (like caching method ids).
 ///
 /// @return Returns a global reference to the class
-local_ref<JClass> findClassLocal(const char* name);
+FBEXPORT local_ref<JClass> findClassLocal(const char* name);

 /// Check to see if two references refer to the same object. Comparison with nullptr
 /// returns true if and only if compared to another nullptr. A weak reference that
 /// refers to a reclaimed object count as nullptr.
-bool isSameObject(alias_ref<JObject> lhs, alias_ref<JObject> rhs) noexcept;
+FBEXPORT bool isSameObject(alias_ref<JObject> lhs, alias_ref<JObject> rhs) noexcept;

 // Together, these classes allow convenient use of any class with the fbjni
 // helpers.  To use:
@@ -75,7 +70,7 @@ bool isSameObject(alias_ref<JObject> lhs, alias_ref<JObject> rhs) noexcept;
 //   constexpr static auto kJavaDescriptor = "Lcom/example/package/MyClass;";
 //
 //   void foo() {
-//     static const auto method = javaClassStatic()->getMethod<void()>("foo");
+//     static auto method = javaClassStatic()->getMethod<void()>("foo");
 //     method(self());
 //   }
 //
@@ -99,7 +94,7 @@ static local_ref<JC> newInstance(Args... args);

 class MonitorLock;

-class JObject : detail::JObjectBase {
+class FBEXPORT JObject : detail::JObjectBase {
 public:
  static constexpr auto kJavaDescriptor = "Ljava/lang/Object;";

@@ -120,12 +115,10 @@ public:
  template<typename T>
  local_ref<T*> getFieldValue(JField<T*> field) const noexcept;

-  /// Set the value of field. Any Java type is accepted.
+  /// Set the value of field. Any Java type is accepted, including the primitive types
+  /// and raw reference types.
  template<typename T>
  void setFieldValue(JField<T> field, T value) noexcept;
-  template<typename T,
-           typename = typename std::enable_if<IsPlainJniReference<T>(), T>::type>
-  void setFieldValue(JField<T> field, alias_ref<T> value) noexcept;

  /// Convenience method to create a std::string representing the object
  std::string toString() const;
@@ -197,7 +190,7 @@ struct JTypeFor<T, Base, void> {
 // jthrowable) to be used as javaobject. This should only be necessary for
 // built-in jni types and not user-defined ones.
 template <typename T, typename Base = JObject, typename JType = void>
-class JavaClass : public Base {
+class FBEXPORT JavaClass : public Base {
  using JObjType = typename detail::JTypeFor<T, Base, JType>;
 public:
  using _javaobject = typename JObjType::_javaobject;
@@ -225,7 +218,7 @@ protected:
 /// Wrapper to provide functionality to jclass references
 struct NativeMethod;

-class JClass : public JavaClass<JClass, JObject, jclass> {
+class FBEXPORT JClass : public JavaClass<JClass, JObject, jclass> {
 public:
  /// Java type descriptor
  static constexpr const char* kJavaDescriptor = "Ljava/lang/Class;";
@@ -302,12 +295,10 @@ class JClass : public JavaClass<JClass, JObject, jclass> {
  template<typename T>
  local_ref<T*> getStaticFieldValue(JStaticField<T*> field) noexcept;

-  /// Set the value of field. Any Java type is accepted.
+  /// Set the value of field. Any Java type is accepted, including the primitive types
+  /// and raw reference types.
  template<typename T>
  void setStaticFieldValue(JStaticField<T> field, T value) noexcept;
-  template<typename T,
-           typename = typename std::enable_if<IsPlainJniReference<T>(), T>::type>
-  void setStaticFieldValue(JStaticField<T> field, alias_ref<T> value) noexcept;

  /// Allocates a new object and invokes the specified constructor
  template<typename R, typename... Args>
@@ -339,23 +330,27 @@ private:
 void registerNatives(const char* name, std::initializer_list<NativeMethod> methods);

 /// Wrapper to provide functionality to jstring references
-class JString : public JavaClass<JString, JObject, jstring> {
+class FBEXPORT JString : public JavaClass<JString, JObject, jstring> {
 public:
  /// Java type descriptor
  static constexpr const char* kJavaDescriptor = "Ljava/lang/String;";

  /// Convenience method to convert a jstring object to a std::string
  std::string toStdString() const;
-
-  /// Convenience method to convert a jstring object to a std::u16string
-  std::u16string toU16String() const;
 };

-/// Convenience functions to convert a const char*, std::string, or std::u16string
-/// into a @ref local_ref to a jstring.
-local_ref<JString> make_jstring(const char* modifiedUtf8);
-local_ref<JString> make_jstring(const std::string& modifiedUtf8);
-local_ref<JString> make_jstring(const std::u16string& utf16);
+/// Convenience functions to convert a std::string or const char* into a @ref local_ref to a
+/// jstring
+FBEXPORT local_ref<JString> make_jstring(const char* modifiedUtf8);
+FBEXPORT local_ref<JString> make_jstring(const std::string& modifiedUtf8);
+
+/// Wrapper to provide functionality to jthrowable references
+class FBEXPORT JThrowable : public JavaClass<JThrowable, JObject, jthrowable> {
+ public:
+  static constexpr const char* kJavaDescriptor = "Ljava/lang/Throwable;";
+
+  local_ref<JThrowable> initCause(alias_ref<JThrowable> cause);
+};

 namespace detail {
 template<typename Target>
@@ -383,7 +378,7 @@ class ElementProxy {
 }

 namespace detail {
-class JArray : public JavaClass<JArray, JObject, jarray> {
+class FBEXPORT JArray : public JavaClass<JArray, JObject, jarray> {
 public:
  // This cannot be used in a scope that derives a descriptor (like in a method
  // signature). Use a more derived type instead (like JArrayInt or
@@ -395,7 +390,7 @@ class JArray : public JavaClass<JArray, JObject, jarray> {
 // This is used so that the JArrayClass<T> javaobject extends jni's
 // jobjectArray. This class should not be used directly. A general Object[]
 // should use JArrayClass<jobject>.
-class JTypeArray : public JavaClass<JTypeArray, JArray, jobjectArray> {
+class FBEXPORT JTypeArray : public JavaClass<JTypeArray, JArray, jobjectArray> {
  // This cannot be used in a scope that derives a descriptor (like in a method
  // signature).
  static constexpr const char* kJavaDescriptor = nullptr;
@@ -445,7 +440,9 @@ template <typename T>
 using jtypeArray = typename JArrayClass<T>::javaobject;

 template<typename T>
-local_ref<typename JArrayClass<T>::javaobject> adopt_local_array(jobjectArray ref);
+local_ref<typename JArrayClass<T>::javaobject> adopt_local_array(jobjectArray ref) {
+  return adopt_local(static_cast<typename JArrayClass<T>::javaobject>(ref));
+}

 template<typename Target>
 local_ref<typename Target::javaentry> adopt_local(detail::ElementProxy<Target> elementProxy) {
@@ -463,7 +460,7 @@ template <typename T> class PinnedCriticalAlloc;
 /// This is an empty holder by itself. Construct a PinnedPrimitiveArray to actually interact with
 /// the elements of the array.
 template <typename JArrayType>
-class JPrimitiveArray :
+class FBEXPORT JPrimitiveArray :
    public JavaClass<JPrimitiveArray<JArrayType>, detail::JArray, JArrayType> {
  static_assert(is_jni_primitive_array<JArrayType>(), "");
 public:
@@ -503,14 +500,14 @@ private:
  void releaseElements(T* elements, jint mode);
 };

-local_ref<jbooleanArray> make_boolean_array(jsize size);
-local_ref<jbyteArray> make_byte_array(jsize size);
-local_ref<jcharArray> make_char_array(jsize size);
-local_ref<jshortArray> make_short_array(jsize size);
-local_ref<jintArray> make_int_array(jsize size);
-local_ref<jlongArray> make_long_array(jsize size);
-local_ref<jfloatArray> make_float_array(jsize size);
-local_ref<jdoubleArray> make_double_array(jsize size);
+FBEXPORT local_ref<jbooleanArray> make_boolean_array(jsize size);
+FBEXPORT local_ref<jbyteArray> make_byte_array(jsize size);
+FBEXPORT local_ref<jcharArray> make_char_array(jsize size);
+FBEXPORT local_ref<jshortArray> make_short_array(jsize size);
+FBEXPORT local_ref<jintArray> make_int_array(jsize size);
+FBEXPORT local_ref<jlongArray> make_long_array(jsize size);
+FBEXPORT local_ref<jfloatArray> make_float_array(jsize size);
+FBEXPORT local_ref<jdoubleArray> make_double_array(jsize size);

 using JArrayBoolean = JPrimitiveArray<jbooleanArray>;
 using JArrayByte = JPrimitiveArray<jbyteArray>;
@@ -572,29 +569,6 @@ class PinnedPrimitiveArray {
   friend class JPrimitiveArray<typename jtype_traits<T>::array_type>;
 };

-struct JStackTraceElement : JavaClass<JStackTraceElement> {
-  static auto constexpr kJavaDescriptor = "Ljava/lang/StackTraceElement;";
-
-  static local_ref<javaobject> create(const std::string& declaringClass, const std::string& methodName, const std::string& file, int line);
-
-  std::string getClassName() const;
-  std::string getMethodName() const;
-  std::string getFileName() const;
-  int getLineNumber() const;
-};
-
-/// Wrapper to provide functionality to jthrowable references
-class JThrowable : public JavaClass<JThrowable, JObject, jthrowable> {
- public:
-  static constexpr const char* kJavaDescriptor = "Ljava/lang/Throwable;";
-
-  using JStackTrace = JArrayClass<JStackTraceElement::javaobject>;
-
-  local_ref<JThrowable> initCause(alias_ref<JThrowable> cause);
-  local_ref<JStackTrace> getStackTrace();
-  void setStackTrace(alias_ref<JArrayClass<JStackTraceElement::javaobject>>);
-};
-
 #pragma push_macro("PlainJniRefMap")
 #undef PlainJniRefMap
 #define PlainJniRefMap(rtype, jtype) \
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Exceptions.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Exceptions.h
@@ -23,15 +23,12 @@

 #include <jni.h>

+#include <fb/visibility.h>
+
 #include "Common.h"
 #include "References.h"
 #include "CoreClasses.h"

-#if defined(__ANDROID__) && defined(__ARM_ARCH_5TE__) && !defined(FBJNI_NO_EXCEPTION_PTR)
-// ARMv5 NDK does not support exception_ptr so we cannot use that when building for it.
-#define FBJNI_NO_EXCEPTION_PTR
-#endif
-
 namespace facebook {
 namespace jni {

@@ -60,10 +57,10 @@ class JCppException : public JavaClass<JCppException, JThrowable> {
 *
 * Note: the what() method of this class is not thread-safe (t6900503).
 */
-class JniException : public std::exception {
+class FBEXPORT JniException : public std::exception {
 public:
  JniException();
-  ~JniException() override;
+  ~JniException();

  explicit JniException(alias_ref<jthrowable> throwable);

@@ -73,7 +70,7 @@ class JniException : public std::exception {

  local_ref<JThrowable> getThrowable() const noexcept;

-  const char* what() const noexcept override;
+  virtual const char* what() const noexcept;

  void setJavaException() const noexcept;

@@ -108,23 +105,11 @@ template<typename... Args>
 }

 // Identifies any pending C++ exception and throws it as a Java exception. If the exception can't
-// be thrown, it aborts the program.
-void translatePendingCppExceptionToJavaException();
-
-#ifndef FBJNI_NO_EXCEPTION_PTR
-local_ref<JThrowable> getJavaExceptionForCppException(std::exception_ptr ptr);
-#endif
-
-/***
- * The stack returned may include build ids.  It may be beneficial to
- * call lyra::setLibraryIdentifierFunction before calling this if
- * build ids are desirable.
- */
-local_ref<JThrowable> getJavaExceptionForCppBackTrace();
-
-local_ref<JThrowable> getJavaExceptionForCppBackTrace(const char* msg);
+// be thrown, it aborts the program. This is a noexcept function at C++ level.
+FBEXPORT void translatePendingCppExceptionToJavaException() noexcept;

 // For convenience, some exception names in java.lang are available here.
+
 const char* const gJavaLangIllegalArgumentException = "java/lang/IllegalArgumentException";

 }}
--- a/lib/fb/src/main/cpp/include/fb/fbjni/File.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/File.h
@@ -6,7 +6,7 @@
 */
 #pragma once

-#include <fbjni/fbjni.h>
+#include "CoreClasses.h"

 namespace facebook {
 namespace jni {
@@ -17,7 +17,7 @@ class JFile : public JavaClass<JFile> {

  // Define a method that calls into the represented Java class
  std::string getAbsolutePath() {
-    static const auto method = getClass()->getMethod<jstring()>("getAbsolutePath");
+    static auto method = getClass()->getMethod<jstring()>("getAbsolutePath");
    return method(self())->toStdString();
  }

--- a/lib/fb/src/main/cpp/include/fbjni/detail/Hybrid.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Hybrid.h
@@ -9,6 +9,9 @@
 #include <memory>
 #include <type_traits>

+#include <fb/assert.h>
+#include <fb/visibility.h>
+
 #include "CoreClasses.h"

 namespace facebook {
@@ -21,45 +24,13 @@ public:
  virtual ~BaseHybridClass() {}
 };

-struct HybridData : public JavaClass<HybridData> {
+struct FBEXPORT HybridData : public JavaClass<HybridData> {
  constexpr static auto kJavaDescriptor = "Lcom/facebook/jni/HybridData;";
+  void setNativePointer(std::unique_ptr<BaseHybridClass> new_value);
+  BaseHybridClass* getNativePointer();
  static local_ref<HybridData> create();
 };

-class HybridDestructor : public JavaClass<HybridDestructor> {
-  public:
-    static auto constexpr kJavaDescriptor = "Lcom/facebook/jni/HybridData$Destructor;";
-
-  detail::BaseHybridClass* getNativePointer();
-
-  void setNativePointer(std::unique_ptr<detail::BaseHybridClass> new_value);
-};
-
-template<typename T>
-detail::BaseHybridClass* getNativePointer(T t) {
-  return getHolder(t)->getNativePointer();
-}
-
-template<typename T>
-void setNativePointer(T t, std::unique_ptr<detail::BaseHybridClass> new_value) {
-  getHolder(t)->setNativePointer(std::move(new_value));
-}
-
-template<typename T>
-local_ref<HybridDestructor> getHolder(T t) {
-  static auto holderField = t->getClass()->template getField<HybridDestructor::javaobject>("mDestructor");
-  return t->getFieldValue(holderField);
-}
-
-// JavaClass for HybridClassBase
-struct HybridClassBase : public JavaClass<HybridClassBase> {
-  constexpr static auto kJavaDescriptor = "Lcom/facebook/jni/HybridClassBase;";
-
-  static bool isHybridClassBase(alias_ref<jclass> jclass) {
-    return HybridClassBase::javaClassStatic()->isAssignableFrom(jclass);
-  }
-};
-
 template <typename Base, typename Enabled = void>
 struct HybridTraits {
  // This static assert should actually always fail if we don't use one of the
@@ -94,7 +65,7 @@ struct HybridTraits<

 // convert to HybridClass* from jhybridobject
 template <typename T>
-struct Convert<
+struct FBEXPORT Convert<
  T, typename std::enable_if<
    std::is_base_of<BaseHybridClass, typename std::remove_pointer<T>::type>::value>::type> {
  typedef typename std::remove_pointer<T>::type::jhybridobject jniType;
@@ -119,7 +90,7 @@ struct RefReprType<T, typename std::enable_if<std::is_base_of<BaseHybridClass, T
 }

 template <typename T, typename Base = detail::BaseHybridClass>
-class HybridClass : public detail::HybridTraits<Base>::CxxBase {
+class FBEXPORT HybridClass : public detail::HybridTraits<Base>::CxxBase {
 public:
  struct JavaPart : JavaClass<JavaPart, typename detail::HybridTraits<Base>::JavaBase> {
    // At this point, T is incomplete, and so we cannot access
@@ -136,7 +107,6 @@ public:
    T* cthis();

    friend class HybridClass;
-    friend T;
  };

  using jhybridobject = typename JavaPart::javaobject;
@@ -166,7 +136,7 @@ protected:

  static local_ref<detail::HybridData> makeHybridData(std::unique_ptr<T> cxxPart) {
    auto hybridData = detail::HybridData::create();
-    setNativePointer(hybridData, std::move(cxxPart));
+    hybridData->setNativePointer(std::move(cxxPart));
    return hybridData;
  }

@@ -175,11 +145,6 @@ protected:
    return makeHybridData(std::unique_ptr<T>(new T(std::forward<Args>(args)...)));
  }

-  template <typename... Args>
-  static void setCxxInstance(alias_ref<jhybridobject> o, Args&&... args) {
-    setNativePointer(o, std::unique_ptr<T>(new T(std::forward<Args>(args)...)));
-  }
-
 public:
  // Factory method for creating a hybrid object where the arguments
  // are used to initialize the C++ part directly without passing them
@@ -193,23 +158,11 @@ public:
  // C++ object fails, or any JNI methods throw.
  template <typename... Args>
  static local_ref<JavaPart> newObjectCxxArgs(Args&&... args) {
-    static bool isHybrid = detail::HybridClassBase::isHybridClassBase(javaClassStatic());
-    auto cxxPart = std::unique_ptr<T>(new T(std::forward<Args>(args)...));
-
-    local_ref<JavaPart> result;
-    if (isHybrid) {
-      result = JavaPart::newInstance();
-      setNativePointer(result, std::move(cxxPart));
-    }
-    else {
-      auto hybridData = makeHybridData(std::move(cxxPart));
-      result = JavaPart::newInstance(hybridData);
-    }
-
-    return result;
+    auto hybridData = makeCxxInstance(std::forward<Args>(args)...);
+    return JavaPart::newInstance(hybridData);
  }

- // TODO? Create reusable interface for Allocatable classes and use it to
+  // TODO? Create reusable interface for Allocatable classes and use it to
  // strengthen type-checking (and possibly provide a default
  // implementation of allocate().)
  template <typename... Args>
@@ -241,23 +194,17 @@ public:

 template <typename T, typename B>
 inline T* HybridClass<T, B>::JavaPart::cthis() {
-  detail::BaseHybridClass* result = 0;
-  static bool isHybrid = detail::HybridClassBase::isHybridClassBase(this->getClass());
-  if (isHybrid) {
-    result = getNativePointer(this);
-  } else {
-    static auto field =
-      HybridClass<T, B>::JavaPart::javaClassStatic()->template getField<detail::HybridData::javaobject>("mHybridData");
-    auto hybridData = this->getFieldValue(field);
-    if (!hybridData) {
-      throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
-    }
-
-    result = getNativePointer(hybridData);
+  static auto field =
+    HybridClass<T, B>::JavaPart::javaClassStatic()->template getField<detail::HybridData::javaobject>("mHybridData");
+  auto hybridData = this->getFieldValue(field);
+  if (!hybridData) {
+    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
  }
-
  // I'd like to use dynamic_cast here, but -fno-rtti is the default.
-  return static_cast<T*>(result);
+  T* value = static_cast<T*>(hybridData->getNativePointer());
+  // This would require some serious programmer error.
+  FBASSERTMSGF(value != 0, "Incorrect C++ type in hybrid field");
+  return value;
 };

 template <typename T, typename B>
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Iterator-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Iterator-inl.h
@@ -32,7 +32,7 @@ struct IteratorHelper : public JavaClass<IteratorHelper<E>> {
  value_type next() {
    static auto elementField =
      JavaBase_::javaClassStatic()->template getField<jobject>("mElement");
-    return dynamic_ref_cast<JniType<E>>(JavaBase_::getFieldValue(elementField));
+    return dynamic_ref_cast<E>(JavaBase_::getFieldValue(elementField));
  }

  static void reset(value_type& v) {
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Iterator.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Iterator.h
--- a/lib/fb/src/main/cpp/include/fb/fbjni/JThread.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/JThread.h
@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include "CoreClasses.h"
+#include "NativeRunnable.h"
+
+namespace facebook {
+namespace jni {
+
+class JThread : public JavaClass<JThread> {
+ public:
+  static constexpr const char* kJavaDescriptor = "Ljava/lang/Thread;";
+
+  void start() {
+    static auto method = javaClassStatic()->getMethod<void()>("start");
+    method(self());
+  }
+
+  void join() {
+    static auto method = javaClassStatic()->getMethod<void()>("join");
+    method(self());
+  }
+
+  static local_ref<JThread> create(std::function<void()>&& runnable) {
+    auto jrunnable = JNativeRunnable::newObjectCxxArgs(std::move(runnable));
+    return newInstance(static_ref_cast<JRunnable::javaobject>(jrunnable));
+  }
+};
+
+}
+}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Meta-forward.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Meta-forward.h
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Meta-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Meta-inl.h
@@ -14,6 +14,10 @@
 #include "References.h"
 #include "Boxed.h"

+#if defined(__ANDROID__)
+#include <sys/system_properties.h>
+#endif
+
 namespace facebook {
 namespace jni {

@@ -59,10 +63,31 @@ local_ref<JArrayClass<jobject>::javaobject> makeArgsArray(Args... args) {
  return arr;
 }

+
+inline bool needsSlowPath(alias_ref<jobject> obj) {
+#if defined(__ANDROID__)
+  // On Android 6.0, art crashes when attempting to call a function on a Proxy.
+  // So, when we detect that case we must use the safe, slow workaround. That is,
+  // we resolve the method id to the corresponding java.lang.reflect.Method object
+  // and make the call via it's invoke() method.
+  static auto android_sdk = ([] {
+     char sdk_version_str[PROP_VALUE_MAX];
+     __system_property_get("ro.build.version.sdk", sdk_version_str);
+     return atoi(sdk_version_str);
+  })();
+  static auto is_bad_android = android_sdk == 23;
+  if (!is_bad_android) return false;
+  static auto proxy_class = findClassStatic("java/lang/reflect/Proxy");
+  return obj->isInstanceOf(proxy_class);
+#else
+  return false;
+#endif
+}
+
 }

 template<typename... Args>
-inline void JMethod<void(Args...)>::operator()(alias_ref<jobject> self, Args... args) const {
+inline void JMethod<void(Args...)>::operator()(alias_ref<jobject> self, Args... args) {
  const auto env = Environment::current();
  env->CallVoidMethod(
        self.get(),
@@ -73,10 +98,10 @@ inline void JMethod<void(Args...)>::operator()(alias_ref<jobject> self, Args...

 #pragma push_macro("DEFINE_PRIMITIVE_CALL")
 #undef DEFINE_PRIMITIVE_CALL
-#define DEFINE_PRIMITIVE_CALL(TYPE, METHOD)                                                    \
+#define DEFINE_PRIMITIVE_CALL(TYPE, METHOD, CLASS)                                             \
 template<typename... Args>                                                                     \
-inline TYPE JMethod<TYPE(Args...)>::operator()(alias_ref<jobject> self, Args... args) const {  \
-  const auto env = Environment::current();                                                     \
+inline TYPE JMethod<TYPE(Args...)>::operator()(alias_ref<jobject> self, Args... args) {        \
+  const auto env = internal::getEnv();                                                         \
  auto result = env->Call ## METHOD ## Method(                                                 \
        self.get(),                                                                            \
        getId(),                                                                               \
@@ -85,14 +110,14 @@ inline TYPE JMethod<TYPE(Args...)>::operator()(alias_ref<jobject> self, Args...
  return result;                                                                               \
 }

-DEFINE_PRIMITIVE_CALL(jboolean, Boolean)
-DEFINE_PRIMITIVE_CALL(jbyte, Byte)
-DEFINE_PRIMITIVE_CALL(jchar, Char)
-DEFINE_PRIMITIVE_CALL(jshort, Short)
-DEFINE_PRIMITIVE_CALL(jint, Int)
-DEFINE_PRIMITIVE_CALL(jlong, Long)
-DEFINE_PRIMITIVE_CALL(jfloat, Float)
-DEFINE_PRIMITIVE_CALL(jdouble, Double)
+DEFINE_PRIMITIVE_CALL(jboolean, Boolean, JBoolean)
+DEFINE_PRIMITIVE_CALL(jbyte, Byte, JByte)
+DEFINE_PRIMITIVE_CALL(jchar, Char, JCharacter)
+DEFINE_PRIMITIVE_CALL(jshort, Short, JShort)
+DEFINE_PRIMITIVE_CALL(jint, Int, JInteger)
+DEFINE_PRIMITIVE_CALL(jlong, Long, JLong)
+DEFINE_PRIMITIVE_CALL(jfloat, Float, JFloat)
+DEFINE_PRIMITIVE_CALL(jdouble, Double, JDouble)
 #pragma pop_macro("DEFINE_PRIMITIVE_CALL")

 /// JMethod specialization for references that wraps the return value in a @ref local_ref
@@ -107,13 +132,13 @@ class JMethod<R(Args...)> : public JMethodBase {
  JMethod(const JMethod& other) noexcept = default;

  /// Invoke a method and return a local reference wrapping the result
-  local_ref<JniRet> operator()(alias_ref<jobject> self, Args... args) const;
+  local_ref<JniRet> operator()(alias_ref<jobject> self, Args... args);

  friend class JClass;
 };

 template<typename R, typename... Args>
-inline auto JMethod<R(Args...)>::operator()(alias_ref<jobject> self, Args... args) const -> local_ref<JniRet> {
+inline auto JMethod<R(Args...)>::operator()(alias_ref<jobject> self, Args... args) -> local_ref<JniRet> {
  const auto env = Environment::current();
  auto result = env->CallObjectMethod(
      self.get(),
@@ -124,8 +149,8 @@ inline auto JMethod<R(Args...)>::operator()(alias_ref<jobject> self, Args... arg
 }

 template<typename... Args>
-inline void JStaticMethod<void(Args...)>::operator()(alias_ref<jclass> cls, Args... args) const {
-  const auto env = Environment::current();
+inline void JStaticMethod<void(Args...)>::operator()(alias_ref<jclass> cls, Args... args) {
+  const auto env = internal::getEnv();
  env->CallStaticVoidMethod(
        cls.get(),
        getId(),
@@ -137,8 +162,8 @@ inline void JStaticMethod<void(Args...)>::operator()(alias_ref<jclass> cls, Args
 #undef DEFINE_PRIMITIVE_STATIC_CALL
 #define DEFINE_PRIMITIVE_STATIC_CALL(TYPE, METHOD)                                             \
 template<typename... Args>                                                                     \
-inline TYPE JStaticMethod<TYPE(Args...)>::operator()(alias_ref<jclass> cls, Args... args) const { \
-  const auto env = Environment::current();                                                         \
+inline TYPE JStaticMethod<TYPE(Args...)>::operator()(alias_ref<jclass> cls, Args... args) {    \
+  const auto env = internal::getEnv();                                                         \
  auto result = env->CallStatic ## METHOD ## Method(                                           \
        cls.get(),                                                                             \
        getId(),                                                                               \
@@ -169,8 +194,8 @@ class JStaticMethod<R(Args...)> : public JMethodBase {
  JStaticMethod(const JStaticMethod& other) noexcept = default;

  /// Invoke a method and return a local reference wrapping the result
-  local_ref<JniRet> operator()(alias_ref<jclass> cls, Args... args) const {
-    const auto env = Environment::current();
+  local_ref<JniRet> operator()(alias_ref<jclass> cls, Args... args) {
+    const auto env = internal::getEnv();
    auto result = env->CallStaticObjectMethod(
          cls.get(),
          getId(),
@@ -184,8 +209,8 @@ class JStaticMethod<R(Args...)> : public JMethodBase {

 template<typename... Args>
 inline void
-JNonvirtualMethod<void(Args...)>::operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) const {
-  const auto env = Environment::current();
+JNonvirtualMethod<void(Args...)>::operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) {
+  const auto env = internal::getEnv();
  env->CallNonvirtualVoidMethod(
        self.get(),
        cls.get(),
@@ -199,8 +224,8 @@ JNonvirtualMethod<void(Args...)>::operator()(alias_ref<jobject> self, alias_ref<
 #define DEFINE_PRIMITIVE_NON_VIRTUAL_CALL(TYPE, METHOD)                                                      \
 template<typename... Args>                                                                                   \
 inline TYPE                                                                                                  \
-JNonvirtualMethod<TYPE(Args...)>::operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) const { \
-  const auto env = Environment::current();                                                                   \
+JNonvirtualMethod<TYPE(Args...)>::operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) { \
+  const auto env = internal::getEnv();                                                                       \
  auto result = env->CallNonvirtual ## METHOD ## Method(                                                     \
        self.get(),                                                                                          \
        cls.get(),                                                                                           \
@@ -231,8 +256,8 @@ class JNonvirtualMethod<R(Args...)> : public JMethodBase {
  JNonvirtualMethod(const JNonvirtualMethod& other) noexcept = default;

  /// Invoke a method and return a local reference wrapping the result
-  local_ref<JniRet> operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) const {
-    const auto env = Environment::current();
+  local_ref<JniRet> operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args){
+    const auto env = internal::getEnv();
    auto result = env->CallNonvirtualObjectMethod(
          self.get(),
          cls.get(),
@@ -281,13 +306,13 @@ inline jfieldID JField<T>::getId() const noexcept {
 #define DEFINE_FIELD_PRIMITIVE_GET_SET(TYPE, METHOD)                 \
 template<>                                                           \
 inline TYPE JField<TYPE>::get(jobject object) const noexcept {       \
-  const auto env = Environment::current();                           \
+  const auto env = internal::getEnv();                               \
  return env->Get ## METHOD ## Field(object, field_id_);             \
 }                                                                    \
                                                                     \
 template<>                                                           \
 inline void JField<TYPE>::set(jobject object, TYPE value) noexcept { \
-  const auto env = Environment::current();                           \
+  const auto env = internal::getEnv();                               \
  env->Set ## METHOD ## Field(object, field_id_, value);             \
 }

@@ -303,12 +328,12 @@ DEFINE_FIELD_PRIMITIVE_GET_SET(jdouble, Double)

 template<typename T>
 inline T JField<T>::get(jobject object) const noexcept {
-  return static_cast<T>(Environment::current()->GetObjectField(object, field_id_));
+  return static_cast<T>(internal::getEnv()->GetObjectField(object, field_id_));
 }

 template<typename T>
 inline void JField<T>::set(jobject object, T value) noexcept {
-  Environment::current()->SetObjectField(object, field_id_, static_cast<jobject>(value));
+  internal::getEnv()->SetObjectField(object, field_id_, static_cast<jobject>(value));
 }

 // JStaticField<T> /////////////////////////////////////////////////////////////////////////////////
@@ -333,13 +358,13 @@ inline jfieldID JStaticField<T>::getId() const noexcept {
 #define DEFINE_STATIC_FIELD_PRIMITIVE_GET_SET(TYPE, METHOD)                \
 template<>                                                                 \
 inline TYPE JStaticField<TYPE>::get(jclass jcls) const noexcept {          \
-  const auto env = Environment::current();                                 \
+  const auto env = internal::getEnv();                                     \
  return env->GetStatic ## METHOD ## Field(jcls, field_id_);               \
 }                                                                          \
                                                                           \
 template<>                                                                 \
 inline void JStaticField<TYPE>::set(jclass jcls, TYPE value) noexcept {    \
-  const auto env = Environment::current();                                 \
+  const auto env = internal::getEnv();                                     \
  env->SetStatic ## METHOD ## Field(jcls, field_id_, value);               \
 }

@@ -355,13 +380,13 @@ DEFINE_STATIC_FIELD_PRIMITIVE_GET_SET(jdouble, Double)

 template<typename T>
 inline T JStaticField<T>::get(jclass jcls) const noexcept {
-  const auto env = Environment::current();
+  const auto env = internal::getEnv();
  return static_cast<T>(env->GetStaticObjectField(jcls, field_id_));
 }

 template<typename T>
 inline void JStaticField<T>::set(jclass jcls, T value) noexcept {
-  Environment::current()->SetStaticObjectField(jcls, field_id_, value);
+  internal::getEnv()->SetStaticObjectField(jcls, field_id_, value);
 }


--- a/lib/fb/src/main/cpp/include/fbjni/detail/Meta.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Meta.h
@@ -80,7 +80,7 @@ class JMethod<TYPE(Args...)> : public JMethodBase {
  JMethod() noexcept {};                                                         \
  JMethod(const JMethod& other) noexcept = default;                              \
                                                                                 \
-  TYPE operator()(alias_ref<jobject> self, Args... args) const;                  \
+  TYPE operator()(alias_ref<jobject> self, Args... args);                        \
                                                                                 \
  friend class JClass;                                                           \
 }
@@ -130,7 +130,7 @@ class JStaticMethod<TYPE(Args...)> : public JMethodBase {                   \
  JStaticMethod() noexcept {};                                              \
  JStaticMethod(const JStaticMethod& other) noexcept = default;             \
                                                                            \
-  TYPE operator()(alias_ref<jclass> cls, Args... args) const;               \
+  TYPE operator()(alias_ref<jclass> cls, Args... args);                     \
                                                                            \
  friend class JClass;                                                      \
 }
@@ -170,7 +170,7 @@ class JNonvirtualMethod<TYPE(Args...)> : public JMethodBase {               \
  JNonvirtualMethod() noexcept {};                                          \
  JNonvirtualMethod(const JNonvirtualMethod& other) noexcept = default;     \
                                                                            \
-  TYPE operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args) const; \
+  TYPE operator()(alias_ref<jobject> self, alias_ref<jclass> cls, Args... args);       \
                                                                            \
  friend class JClass;                                                      \
 }
--- a/lib/fb/src/main/cpp/include/fbjni/detail/MetaConvert.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/MetaConvert.h
@@ -66,25 +66,6 @@ struct Convert<bool> {
  }
 };

-// Sometimes (64-bit Android) jlong is "long long", but int64_t is "long".
-// Allow int64_t to work as jlong.
-template<typename T>
-struct Convert<T,
-    typename std::enable_if<
-      (std::is_same<T, long long>::value || std::is_same<T, int64_t>::value) && !std::is_same<T, jlong>::value
-    >::type> {
-  typedef jlong jniType;
-  static T fromJni(jniType t) {
-    return t;
-  }
-  static jniType toJniRet(T t) {
-    return t;
-  }
-  static jniType toCall(T t) {
-    return t;
-  }
-};
-
 // convert to alias_ref<T> from T
 template <typename T>
 struct Convert<alias_ref<T>> {
@@ -118,21 +99,7 @@ template <typename T>
 struct Convert<global_ref<T>> {
  typedef JniType<T> jniType;
  // No automatic synthesis of global_ref
-  static jniType toJniRet(global_ref<jniType>&& t) {
-    // If this gets called, ownership the global_ref was passed in here.  (It's
-    // probably a copy of a persistent global_ref made when a function was
-    // declared to return a global_ref, but it could moved out or otherwise not
-    // referenced elsewhere.  Doesn't matter.)  Either way, the only safe way
-    // to return it is to make a local_ref, release it, and return the
-    // underlying local jobject.
-    auto ret = make_local(t);
-    return ret.release();
-  }
-  static jniType toJniRet(const global_ref<jniType>& t) {
-    // If this gets called, the function was declared to return const&.  We
-    // have a ref to a global_ref whose lifetime will exceed this call, so we
-    // can just get the underlying jobject and return it to java without
-    // needing to make a local_ref.
+  static jniType toJniRet(global_ref<jniType> t) {
    return t.get();
  }
  static jniType toCall(global_ref<jniType> t) {
--- a/lib/fb/src/main/cpp/include/fb/fbjni/NativeRunnable.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/NativeRunnable.h
@@ -6,7 +6,9 @@
 */
 #pragma once

-#include <fbjni/fbjni.h>
+#include "CoreClasses.h"
+#include "Hybrid.h"
+#include "Registration.h"

 #include <functional>

--- a/lib/fb/src/main/cpp/include/fbjni/detail/ReferenceAllocators-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/ReferenceAllocators-inl.h
@@ -10,8 +10,6 @@
 #include <new>
 #include <atomic>

-#include "Environment.h"
-
 namespace facebook {
 namespace jni {

@@ -20,8 +18,7 @@ namespace internal {

 // Statistics mostly provided for test (only updated if FBJNI_DEBUG_REFS is defined)
 struct ReferenceStats {
-  std::atomic_uint locals_created, globals_created, weaks_created,
-                   locals_deleted, globals_deleted, weaks_deleted;
+  std::atomic_uint locals_deleted, globals_deleted, weaks_deleted;

  void reset() noexcept;
 };
@@ -35,10 +32,7 @@ extern ReferenceStats g_reference_stats;

 inline jobject LocalReferenceAllocator::newReference(jobject original) const {
  internal::dbglog("Local new: %p", original);
-  #ifdef FBJNI_DEBUG_REFS
-    ++internal::g_reference_stats.locals_created;
-  #endif
-  auto ref = Environment::current()->NewLocalRef(original);
+  auto ref = internal::getEnv()->NewLocalRef(original);
  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
  return ref;
 }
@@ -51,12 +45,15 @@ inline void LocalReferenceAllocator::deleteReference(jobject reference) const no
      ++internal::g_reference_stats.locals_deleted;
    #endif
    assert(verifyReference(reference));
-    Environment::current()->DeleteLocalRef(reference);
+    internal::getEnv()->DeleteLocalRef(reference);
  }
 }

 inline bool LocalReferenceAllocator::verifyReference(jobject reference) const noexcept {
-  return isObjectRefType(reference, JNILocalRefType);
+  if (!reference || !internal::doesGetObjectRefTypeWork()) {
+    return true;
+  }
+  return internal::getEnv()->GetObjectRefType(reference) == JNILocalRefType;
 }


@@ -64,10 +61,7 @@ inline bool LocalReferenceAllocator::verifyReference(jobject reference) const no

 inline jobject GlobalReferenceAllocator::newReference(jobject original) const {
  internal::dbglog("Global new: %p", original);
-  #ifdef FBJNI_DEBUG_REFS
-    ++internal::g_reference_stats.globals_created;
-  #endif
-  auto ref = Environment::current()->NewGlobalRef(original);
+  auto ref = internal::getEnv()->NewGlobalRef(original);
  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
  return ref;
 }
@@ -80,12 +74,15 @@ inline void GlobalReferenceAllocator::deleteReference(jobject reference) const n
      ++internal::g_reference_stats.globals_deleted;
    #endif
    assert(verifyReference(reference));
-    Environment::current()->DeleteGlobalRef(reference);
+    internal::getEnv()->DeleteGlobalRef(reference);
  }
 }

 inline bool GlobalReferenceAllocator::verifyReference(jobject reference) const noexcept {
-  return isObjectRefType(reference, JNIGlobalRefType);
+  if (!reference || !internal::doesGetObjectRefTypeWork()) {
+    return true;
+  }
+  return internal::getEnv()->GetObjectRefType(reference) == JNIGlobalRefType;
 }


@@ -93,10 +90,7 @@ inline bool GlobalReferenceAllocator::verifyReference(jobject reference) const n

 inline jobject WeakGlobalReferenceAllocator::newReference(jobject original) const {
  internal::dbglog("Weak global new: %p", original);
-  #ifdef FBJNI_DEBUG_REFS
-    ++internal::g_reference_stats.weaks_created;
-  #endif
-  auto ref = Environment::current()->NewWeakGlobalRef(original);
+  auto ref = internal::getEnv()->NewWeakGlobalRef(original);
  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
  return ref;
 }
@@ -109,12 +103,15 @@ inline void WeakGlobalReferenceAllocator::deleteReference(jobject reference) con
      ++internal::g_reference_stats.weaks_deleted;
    #endif
    assert(verifyReference(reference));
-    Environment::current()->DeleteWeakGlobalRef(reference);
+    internal::getEnv()->DeleteWeakGlobalRef(reference);
  }
 }

 inline bool WeakGlobalReferenceAllocator::verifyReference(jobject reference) const noexcept {
-  return isObjectRefType(reference, JNIWeakGlobalRefType);
+  if (!reference || !internal::doesGetObjectRefTypeWork()) {
+    return true;
+  }
+  return internal::getEnv()->GetObjectRefType(reference) == JNIWeakGlobalRefType;
 }

 }}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/ReferenceAllocators.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/ReferenceAllocators.h
@@ -13,12 +13,14 @@

 #pragma once

+#include <fb/visibility.h>
+
 #include "Common.h"

 namespace facebook { namespace jni {

 /// Allocator that handles local references
-class LocalReferenceAllocator {
+class FBEXPORT LocalReferenceAllocator {
 public:
  jobject newReference(jobject original) const;
  void deleteReference(jobject reference) const noexcept;
@@ -26,7 +28,7 @@ class LocalReferenceAllocator {
 };

 /// Allocator that handles global references
-class GlobalReferenceAllocator {
+class FBEXPORT GlobalReferenceAllocator {
 public:
  jobject newReference(jobject original) const;
  void deleteReference(jobject reference) const noexcept;
@@ -34,20 +36,23 @@ class GlobalReferenceAllocator {
 };

 /// Allocator that handles weak global references
-class WeakGlobalReferenceAllocator {
+class FBEXPORT WeakGlobalReferenceAllocator {
 public:
  jobject newReference(jobject original) const;
  void deleteReference(jobject reference) const noexcept;
  bool verifyReference(jobject reference) const noexcept;
 };

+/// @cond INTERNAL
+namespace internal {
+
 /**
- * @return Helper based on GetObjectRefType.  Since this isn't defined
- * on all versions of Java or Android, if the type can't be
- * determined, this returns true.  If reference is nullptr, returns
- * true.
+ * @return true iff env->GetObjectRefType is expected to work properly.
 */
-bool isObjectRefType(jobject reference, jobjectRefType refType);
+FBEXPORT bool doesGetObjectRefTypeWork();
+
+}
+/// @endcond

 }}

--- a/lib/fb/src/main/cpp/include/fbjni/detail/References-forward.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/References-forward.h
--- a/lib/fb/src/main/cpp/include/fbjni/detail/References-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/References-inl.h
@@ -173,29 +173,6 @@ operator!=(const T1& a, const T2& b) {
  return !(a == b);
 }

-template<typename T1>
-inline enable_if_t<IsNonWeakReference<T1>(), bool>
-operator==(const T1& a, std::nullptr_t) {
-  return getPlainJniReference(a) == nullptr;
-}
-
-template<typename T1>
-inline enable_if_t<IsNonWeakReference<T1>(), bool>
-operator==(std::nullptr_t, const T1& a) {
-  return nullptr == getPlainJniReference(a);
-}
-
-template<typename T1>
-inline enable_if_t<IsNonWeakReference<T1>(), bool>
-operator!=(const T1& a, std::nullptr_t) {
-  return !(a == nullptr);
-}
-
-template<typename T1>
-inline enable_if_t<IsNonWeakReference<T1>(), bool>
-operator!=(std::nullptr_t, const T1& a) {
-  return !(nullptr == getPlainJniReference(a));
-}

 // base_owned_ref ///////////////////////////////////////////////////////////////////////

@@ -204,11 +181,10 @@ inline base_owned_ref<T, Alloc>::base_owned_ref() noexcept
  : base_owned_ref(nullptr)
 {}

-template<typename T, typename Alloc>
-inline base_owned_ref<T, Alloc>::base_owned_ref(std::nullptr_t t) noexcept
-  : base_owned_ref(static_cast<javaobject>(nullptr))
-{
-  (void)t;
+template <typename T, typename Alloc>
+inline base_owned_ref<T, Alloc>::base_owned_ref(std::nullptr_t array) noexcept
+    : base_owned_ref(static_cast<javaobject>(nullptr)) {
+  (void)array;
 }

 template<typename T, typename Alloc>
@@ -508,25 +484,22 @@ template<typename T, typename RefType>
 auto dynamic_ref_cast(const RefType& ref) ->
 enable_if_t<IsPlainJniReference<T>(), decltype(static_ref_cast<T>(ref))>
 {
-  if (!ref) {
+  if (! ref) {
    return decltype(static_ref_cast<T>(ref))();
  }

-  static alias_ref<jclass> target_class = findClassStatic(jtype_traits<T>::base_name().c_str());
-  if (!target_class) {
-    throwNewJavaException("java/lang/ClassCastException",
-                          "Could not find class %s.",
-                          jtype_traits<T>::base_name().c_str());
+  std::string target_class_name{jtype_traits<T>::base_name()};

-  }
+  // If not found, will throw an exception.
+  alias_ref<jclass> target_class = findClassStatic(target_class_name.c_str());

  local_ref<jclass> source_class = ref->getClass();

-  if (!target_class->isAssignableFrom(source_class)) {
+  if ( ! source_class->isAssignableFrom(target_class)) {
    throwNewJavaException("java/lang/ClassCastException",
                          "Tried to cast from %s to %s.",
                          source_class->toString().c_str(),
-                          jtype_traits<T>::base_name().c_str());
+                          target_class_name.c_str());
  }

  return static_ref_cast<T>(ref);
--- a/lib/fb/src/main/cpp/include/fbjni/detail/References.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/References.h
@@ -4,7 +4,6 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-
 /** @file References.h
 *
 * Functionality similar to smart pointers, but for references into the VM. Four main reference
@@ -74,6 +73,8 @@

 #include <jni.h>

+#include <fb/visibility.h>
+
 #include "ReferenceAllocators.h"
 #include "TypeTraits.h"
 #include "References-forward.h"
@@ -249,26 +250,6 @@ template<typename T1, typename T2>
 enable_if_t<IsNonWeakReference<T1>() && IsNonWeakReference<T2>(), bool>
 operator!=(const T1& a, const T2& b);

-/**
- * Compare references against nullptr
- */
-template<typename T1>
-enable_if_t<IsNonWeakReference<T1>(), bool>
-operator==(const T1& a, std::nullptr_t);
-
-template<typename T1>
-enable_if_t<IsNonWeakReference<T1>(), bool>
-operator==(std::nullptr_t, const T1& a);
-
-template<typename T1>
-enable_if_t<IsNonWeakReference<T1>(), bool>
-operator!=(const T1& a, std::nullptr_t);
-
-template<typename T1>
-enable_if_t<IsNonWeakReference<T1>(), bool>
-operator!=(std::nullptr_t, const T1& a);
-
-
 template<typename T, typename Alloc>
 class base_owned_ref {
 public:
@@ -355,7 +336,7 @@ class weak_ref : public base_owned_ref<T, WeakGlobalReferenceAllocator> {
    : base_owned_ref<T, Allocator>{} {}

  /// Create a null reference
-  /* implicit */ weak_ref(std::nullptr_t) noexcept
+  explicit weak_ref(std::nullptr_t) noexcept
    : base_owned_ref<T, Allocator>{nullptr} {}

  /// Copy constructor (note creates a new reference)
@@ -424,7 +405,7 @@ class basic_strong_ref : public base_owned_ref<T, Alloc> {
    : base_owned_ref<T, Alloc>{} {}

  /// Create a null reference
-  /* implicit */ basic_strong_ref(std::nullptr_t) noexcept
+  explicit basic_strong_ref(std::nullptr_t) noexcept
    : base_owned_ref<T, Alloc>{nullptr} {}

  /// Copy constructor (note creates a new reference)
@@ -511,7 +492,7 @@ class alias_ref {
  alias_ref() noexcept;

  /// Create a null reference
-  /* implicit */ alias_ref(std::nullptr_t) noexcept;
+  alias_ref(std::nullptr_t) noexcept;

  /// Copy constructor
  alias_ref(const alias_ref& other) noexcept;
@@ -572,7 +553,7 @@ class alias_ref {
 * This is useful when you have a call which is initiated from C++-land, and therefore
 * doesn't automatically get a local JNI frame managed for you by the JNI framework.
 */
-class JniLocalScope {
+class FBEXPORT JniLocalScope {
 public:
  JniLocalScope(JNIEnv* p_env, jint capacity);
  ~JniLocalScope();
--- a/lib/fb/src/main/cpp/include/fb/fbjni/Registration-inl.h
+++ b/lib/fb/src/main/cpp/include/fb/fbjni/Registration-inl.h
@@ -0,0 +1,206 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include "Exceptions.h"
+#include "Hybrid.h"
+
+namespace facebook {
+namespace jni {
+
+namespace detail {
+
+#ifdef __i386__
+// X86 ABI forces 16 byte stack allignment on calls. Unfortunately
+// sometimes Dalvik chooses not to obey the ABI:
+// - https://code.google.com/p/android/issues/detail?id=61012
+// - https://android.googlesource.com/platform/ndk/+/81696d2%5E!/
+// Therefore, we tell the compiler to re-align the stack on entry
+// to our JNI functions.
+#define JNI_ENTRY_POINT __attribute__((force_align_arg_pointer))
+#else
+#define JNI_ENTRY_POINT
+#endif
+
+// registration wrapper for legacy JNI-style functions
+
+template<typename F, F func, typename C, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(void (*)(JNIEnv*, C, Args... args)) {
+  struct funcWrapper {
+    JNI_ENTRY_POINT static void call(JNIEnv* env, jobject obj, Args... args) {
+      // Note that if func was declared noexcept, then both gcc and clang are smart
+      // enough to elide the try/catch.
+      try {
+        (*func)(env, static_cast<C>(obj), args...);
+      } catch (...) {
+        translatePendingCppExceptionToJavaException();
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+template<typename F, F func, typename C, typename R, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(R (*)(JNIEnv*, C, Args... args)) {
+  struct funcWrapper {
+    JNI_ENTRY_POINT static R call(JNIEnv* env, jobject obj, Args... args) {
+      try {
+        return (*func)(env, static_cast<JniType<C>>(obj), args...);
+      } catch (...) {
+        translatePendingCppExceptionToJavaException();
+        return R{};
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+// registration wrappers for functions, with autoconversion of arguments.
+
+template<typename F, F func, typename C, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(void (*)(alias_ref<C>, Args... args)) {
+  struct funcWrapper {
+    JNI_ENTRY_POINT static void call(JNIEnv*, jobject obj,
+                                     typename Convert<typename std::decay<Args>::type>::jniType... args) {
+      try {
+        (*func)(static_cast<JniType<C>>(obj), Convert<typename std::decay<Args>::type>::fromJni(args)...);
+      } catch (...) {
+        translatePendingCppExceptionToJavaException();
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+template<typename F, F func, typename C, typename R, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(R (*)(alias_ref<C>, Args... args)) {
+  struct funcWrapper {
+
+    JNI_ENTRY_POINT static typename Convert<typename std::decay<R>::type>::jniType call(JNIEnv*, jobject obj,
+                                       typename Convert<typename std::decay<Args>::type>::jniType... args) {
+      try {
+        return Convert<typename std::decay<R>::type>::toJniRet(
+          (*func)(static_cast<JniType<C>>(obj), Convert<typename std::decay<Args>::type>::fromJni(args)...));
+      } catch (...) {
+        using jniRet = typename Convert<typename std::decay<R>::type>::jniType;
+        translatePendingCppExceptionToJavaException();
+        return jniRet{};
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+// registration wrappers for non-static methods, with autoconvertion of arguments.
+
+template <typename M, M method, typename C, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(
+    void (C::*method0)(Args... args)) {
+  (void)method0;
+  struct funcWrapper {
+    JNI_ENTRY_POINT static void call(JNIEnv* env, jobject obj,
+                                     typename Convert<typename std::decay<Args>::type>::jniType... args) {
+      try {
+        try {
+          auto aref = wrap_alias(static_cast<typename C::jhybridobject>(obj));
+          // This is usually a noop, but if the hybrid object is a
+          // base class of other classes which register JNI methods,
+          // this will get the right type for the registered method.
+          auto cobj = static_cast<C*>(facebook::jni::cthis(aref));
+          (cobj->*method)(Convert<typename std::decay<Args>::type>::fromJni(args)...);
+        } catch (const std::exception& ex) {
+          C::mapException(ex);
+          throw;
+        }
+      } catch (...) {
+        translatePendingCppExceptionToJavaException();
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+template<typename M, M method, typename C, typename R, typename... Args>
+inline NativeMethodWrapper* exceptionWrapJNIMethod(R (C::*method0)(Args... args)) {
+  struct funcWrapper {
+
+    JNI_ENTRY_POINT static typename Convert<typename std::decay<R>::type>::jniType call(JNIEnv* env, jobject obj,
+                                       typename Convert<typename std::decay<Args>::type>::jniType... args) {
+      try {
+        try {
+          auto aref = wrap_alias(static_cast<typename C::jhybridobject>(obj));
+          // This is usually a noop, but if the hybrid object is a
+          // base class of other classes which register JNI methods,
+          // this will get the right type for the registered method.
+          auto cobj = static_cast<C*>(facebook::jni::cthis(aref));
+          return Convert<typename std::decay<R>::type>::toJniRet(
+            (cobj->*method)(Convert<typename std::decay<Args>::type>::fromJni(args)...));
+        } catch (const std::exception& ex) {
+          C::mapException(ex);
+          throw;
+        }
+      } catch (...) {
+        using jniRet = typename Convert<typename std::decay<R>::type>::jniType;
+        translatePendingCppExceptionToJavaException();
+        return jniRet{};
+      }
+    }
+  };
+
+  // This intentionally erases the real type; JNI will do it anyway
+  return reinterpret_cast<NativeMethodWrapper*>(&(funcWrapper::call));
+}
+
+template<typename R, typename C, typename... Args>
+inline std::string makeDescriptor(R (*)(JNIEnv*, C, Args... args)) {
+  return jmethod_traits<R(Args...)>::descriptor();
+}
+
+template<typename R, typename C, typename... Args>
+inline std::string makeDescriptor(R (*)(alias_ref<C>, Args... args)) {
+  return jmethod_traits_from_cxx<R(Args...)>::descriptor();
+}
+
+template<typename R, typename C, typename... Args>
+inline std::string makeDescriptor(R (C::*)(Args... args)) {
+  return jmethod_traits_from_cxx<R(Args...)>::descriptor();
+}
+
+template <typename R, typename... Args>
+template <R (*func)(Args...)>
+JNI_ENTRY_POINT R CriticalMethod<R (*)(Args...)>::call(
+    alias_ref<jclass>,
+    Args... args) noexcept {
+  static_assert(
+      IsJniPrimitive<R>() || std::is_void<R>(),
+      "Critical Native Methods may only return primitive JNI types, or void.");
+  static_assert(
+      AreJniPrimitives<Args...>(),
+      "Critical Native Methods may only use primitive JNI types as parameters");
+
+  return func(std::forward<Args>(args)...);
+}
+
+template <typename R, typename... Args>
+template <R (*func)(Args...)>
+inline std::string CriticalMethod<R (*)(Args...)>::desc() {
+  return makeDescriptor(call<func>);
+}
+
+}
+
+}}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Registration.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Registration.h
@@ -17,14 +17,28 @@ namespace detail {
 // This uses the real JNI function as a non-type template parameter to
 // cause a (static member) function to exist with the same signature,
 // but with try/catch exception translation.
+template<typename F, F func, typename C, typename... Args>
+NativeMethodWrapper* exceptionWrapJNIMethod(void (*func0)(JNIEnv*, jobject, Args... args));
+
+// Same as above, but for non-void return types.
 template<typename F, F func, typename C, typename R, typename... Args>
 NativeMethodWrapper* exceptionWrapJNIMethod(R (*func0)(JNIEnv*, jobject, Args... args));

 // Automatically wrap object argument, and don't take env explicitly.
+template<typename F, F func, typename C, typename... Args>
+NativeMethodWrapper* exceptionWrapJNIMethod(void (*func0)(alias_ref<C>, Args... args));
+
+// Automatically wrap object argument, and don't take env explicitly,
+// non-void return type.
 template<typename F, F func, typename C, typename R, typename... Args>
 NativeMethodWrapper* exceptionWrapJNIMethod(R (*func0)(alias_ref<C>, Args... args));

+// Extract C++ instance from object, and invoke given method on it.
+template<typename M, M method, typename C, typename... Args>
+NativeMethodWrapper* exceptionWrapJNIMethod(void (C::*method0)(Args... args));
+
 // Extract C++ instance from object, and invoke given method on it,
+// non-void return type
 template<typename M, M method, typename C, typename R, typename... Args>
 NativeMethodWrapper* exceptionWrapJNIMethod(R (C::*method0)(Args... args));

@@ -43,15 +57,15 @@ std::string makeDescriptor(R (*func)(alias_ref<C>, Args... args));
 template<typename R, typename C, typename... Args>
 std::string makeDescriptor(R (C::*method0)(Args... args));

-template<typename F>
+template <typename F>
 struct CriticalMethod;

-template<typename R, typename ...Args>
-struct CriticalMethod<R(*)(Args...)> {
-  template<R(*func)(Args...)>
+template <typename R, typename... Args>
+struct CriticalMethod<R (*)(Args...)> {
+  template <R (*func)(Args...)>
  static R call(alias_ref<jclass>, Args... args) noexcept;

-  template<R(*func)(Args...)>
+  template <R (*func)(Args...)>
  inline static std::string desc();
 };

@@ -77,7 +91,6 @@ struct CriticalMethod<R(*)(Args...)> {
 #define makeNativeMethodN(a, b, c, count, ...) makeNativeMethod ## count
 #define makeNativeMethod(...) makeNativeMethodN(__VA_ARGS__, 3, 2)(__VA_ARGS__)

-
 // FAST CALLS / CRITICAL CALLS
 // Android up to and including v7 supports "fast calls" by prefixing the method
 // signature with an exclamation mark.
--- a/lib/fb/src/main/cpp/include/fbjni/detail/TypeTraits.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/TypeTraits.h
@@ -86,7 +86,6 @@ constexpr bool AreJniPrimitives() {
  return are_jni_primitives<Ts...>::value;
 }

-
 /// Metafunction to determine whether a type is a JNI array of primitives or not
 template <typename T>
 struct is_jni_primitive_array :
--- a/lib/fb/src/main/cpp/include/fb/log.h
+++ b/lib/fb/src/main/cpp/include/fb/log.h
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2005 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * FB Wrapper for logging functions.
+ *
+ * The android logging API uses the macro "LOG()" for its logic, which means
+ * that it conflicts with random other places that use LOG for their own
+ * purposes and doesn't work right half the places you include it
+ *
+ * FBLOG uses exactly the same semantics (FBLOGD for debug etc) but because of
+ * the FB prefix it's strictly better. FBLOGV also gets stripped out based on
+ * whether NDEBUG is set, but can be overridden by FBLOG_NDEBUG
+ *
+ * Most of the rest is a copy of <cutils/log.h> with minor changes.
+ */
+
+//
+// C/C++ logging functions.  See the logging documentation for API details.
+//
+// We'd like these to be available from C code (in case we import some from
+// somewhere), so this has a C interface.
+//
+// The output will be correct when the log file is shared between multiple
+// threads and/or multiple processes so long as the operating system
+// supports O_APPEND.  These calls have mutex-protected data structures
+// and so are NOT reentrant.  Do not use LOG in a signal handler.
+//
+#pragma once
+
+#include <fb/visibility.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef ANDROID
+#include <android/log.h>
+#else
+// These declarations are needed for our internal use even on non-Android
+// builds.
+// (they are borrowed from <android/log.h>)
+
+/*
+ * Android log priority values, in ascending priority order.
+ */
+typedef enum android_LogPriority {
+  ANDROID_LOG_UNKNOWN = 0,
+  ANDROID_LOG_DEFAULT, /* only for SetMinPriority() */
+  ANDROID_LOG_VERBOSE,
+  ANDROID_LOG_DEBUG,
+  ANDROID_LOG_INFO,
+  ANDROID_LOG_WARN,
+  ANDROID_LOG_ERROR,
+  ANDROID_LOG_FATAL,
+  ANDROID_LOG_SILENT, /* only for SetMinPriority(); must be last */
+} android_LogPriority;
+
+/*
+ * Send a simple string to the log.
+ */
+int __android_log_write(int prio, const char *tag, const char *text);
+
+/*
+ * Send a formatted string to the log, used like printf(fmt,...)
+ */
+int __android_log_print(int prio, const char *tag, const char *fmt, ...)
+#if defined(__GNUC__)
+    __attribute__((format(printf, 3, 4)))
+#endif
+    ;
+
+#endif
+
+// ---------------------------------------------------------------------
+
+/*
+ * Normally we strip FBLOGV (VERBOSE messages) from release builds.
+ * You can modify this (for example with "#define FBLOG_NDEBUG 0"
+ * at the top of your source file) to change that behavior.
+ */
+#ifndef FBLOG_NDEBUG
+#ifdef NDEBUG
+#define FBLOG_NDEBUG 1
+#else
+#define FBLOG_NDEBUG 0
+#endif
+#endif
+
+/*
+ * This is the local tag used for the following simplified
+ * logging macros.  You can change this preprocessor definition
+ * before using the other macros to change the tag.
+ */
+#ifndef LOG_TAG
+#define LOG_TAG NULL
+#endif
+
+// ---------------------------------------------------------------------
+
+/*
+ * Simplified macro to send a verbose log message using the current LOG_TAG.
+ */
+#ifndef FBLOGV
+#if FBLOG_NDEBUG
+#define FBLOGV(...) ((void)0)
+#else
+#define FBLOGV(...) ((void)FBLOG(LOG_VERBOSE, LOG_TAG, __VA_ARGS__))
+#endif
+#endif
+
+#define CONDITION(cond) (__builtin_expect((cond) != 0, 0))
+
+#ifndef FBLOGV_IF
+#if FBLOG_NDEBUG
+#define FBLOGV_IF(cond, ...) ((void)0)
+#else
+#define FBLOGV_IF(cond, ...)                                            \
+  ((CONDITION(cond)) ? ((void)FBLOG(LOG_VERBOSE, LOG_TAG, __VA_ARGS__)) \
+                     : (void)0)
+#endif
+#endif
+
+/*
+ * Simplified macro to send a debug log message using the current LOG_TAG.
+ */
+#ifndef FBLOGD
+#define FBLOGD(...) ((void)FBLOG(LOG_DEBUG, LOG_TAG, __VA_ARGS__))
+#endif
+
+#ifndef FBLOGD_IF
+#define FBLOGD_IF(cond, ...) \
+  ((CONDITION(cond)) ? ((void)FBLOG(LOG_DEBUG, LOG_TAG, __VA_ARGS__)) : (void)0)
+#endif
+
+/*
+ * Simplified macro to send an info log message using the current LOG_TAG.
+ */
+#ifndef FBLOGI
+#define FBLOGI(...) ((void)FBLOG(LOG_INFO, LOG_TAG, __VA_ARGS__))
+#endif
+
+#ifndef FBLOGI_IF
+#define FBLOGI_IF(cond, ...) \
+  ((CONDITION(cond)) ? ((void)FBLOG(LOG_INFO, LOG_TAG, __VA_ARGS__)) : (void)0)
+#endif
+
+/*
+ * Simplified macro to send a warning log message using the current LOG_TAG.
+ */
+#ifndef FBLOGW
+#define FBLOGW(...) ((void)FBLOG(LOG_WARN, LOG_TAG, __VA_ARGS__))
+#endif
+
+#ifndef FBLOGW_IF
+#define FBLOGW_IF(cond, ...) \
+  ((CONDITION(cond)) ? ((void)FBLOG(LOG_WARN, LOG_TAG, __VA_ARGS__)) : (void)0)
+#endif
+
+/*
+ * Simplified macro to send an error log message using the current LOG_TAG.
+ */
+#ifndef FBLOGE
+#define FBLOGE(...) ((void)FBLOG(LOG_ERROR, LOG_TAG, __VA_ARGS__))
+#endif
+
+#ifndef FBLOGE_IF
+#define FBLOGE_IF(cond, ...) \
+  ((CONDITION(cond)) ? ((void)FBLOG(LOG_ERROR, LOG_TAG, __VA_ARGS__)) : (void)0)
+#endif
+
+// ---------------------------------------------------------------------
+
+/*
+ * Conditional based on whether the current LOG_TAG is enabled at
+ * verbose priority.
+ */
+#ifndef IF_FBLOGV
+#if FBLOG_NDEBUG
+#define IF_FBLOGV() if (false)
+#else
+#define IF_FBLOGV() IF_FBLOG(LOG_VERBOSE, LOG_TAG)
+#endif
+#endif
+
+/*
+ * Conditional based on whether the current LOG_TAG is enabled at
+ * debug priority.
+ */
+#ifndef IF_FBLOGD
+#define IF_FBLOGD() IF_FBLOG(LOG_DEBUG, LOG_TAG)
+#endif
+
+/*
+ * Conditional based on whether the current LOG_TAG is enabled at
+ * info priority.
+ */
+#ifndef IF_FBLOGI
+#define IF_FBLOGI() IF_FBLOG(LOG_INFO, LOG_TAG)
+#endif
+
+/*
+ * Conditional based on whether the current LOG_TAG is enabled at
+ * warn priority.
+ */
+#ifndef IF_FBLOGW
+#define IF_FBLOGW() IF_FBLOG(LOG_WARN, LOG_TAG)
+#endif
+
+/*
+ * Conditional based on whether the current LOG_TAG is enabled at
+ * error priority.
+ */
+#ifndef IF_FBLOGE
+#define IF_FBLOGE() IF_FBLOG(LOG_ERROR, LOG_TAG)
+#endif
+
+// ---------------------------------------------------------------------
+
+/*
+ * Log a fatal error.  If the given condition fails, this stops program
+ * execution like a normal assertion, but also generating the given message.
+ * It is NOT stripped from release builds.  Note that the condition test
+ * is -inverted- from the normal assert() semantics.
+ */
+#define FBLOG_ALWAYS_FATAL_IF(cond, ...)                                   \
+  ((CONDITION(cond)) ? ((void)fb_printAssert(#cond, LOG_TAG, __VA_ARGS__)) \
+                     : (void)0)
+
+#define FBLOG_ALWAYS_FATAL(...) \
+  (((void)fb_printAssert(NULL, LOG_TAG, __VA_ARGS__)))
+
+/*
+ * Versions of LOG_ALWAYS_FATAL_IF and LOG_ALWAYS_FATAL that
+ * are stripped out of release builds.
+ */
+#if FBLOG_NDEBUG
+
+#define FBLOG_FATAL_IF(cond, ...) ((void)0)
+#define FBLOG_FATAL(...) ((void)0)
+
+#else
+
+#define FBLOG_FATAL_IF(cond, ...) FBLOG_ALWAYS_FATAL_IF(cond, __VA_ARGS__)
+#define FBLOG_FATAL(...) FBLOG_ALWAYS_FATAL(__VA_ARGS__)
+
+#endif
+
+/*
+ * Assertion that generates a log message when the assertion fails.
+ * Stripped out of release builds.  Uses the current LOG_TAG.
+ */
+#define FBLOG_ASSERT(cond, ...) FBLOG_FATAL_IF(!(cond), __VA_ARGS__)
+//#define LOG_ASSERT(cond) LOG_FATAL_IF(!(cond), "Assertion failed: " #cond)
+
+// ---------------------------------------------------------------------
+
+/*
+ * Basic log message macro.
+ *
+ * Example:
+ *  FBLOG(LOG_WARN, NULL, "Failed with error %d", errno);
+ *
+ * The second argument may be NULL or "" to indicate the "global" tag.
+ */
+#ifndef FBLOG
+#define FBLOG(priority, tag, ...) \
+  FBLOG_PRI(ANDROID_##priority, tag, __VA_ARGS__)
+#endif
+
+#ifndef FBLOG_BY_DELIMS
+#define FBLOG_BY_DELIMS(priority, tag, delims, msg, ...) \
+  logPrintByDelims(ANDROID_##priority, tag, delims, msg, ##__VA_ARGS__)
+#endif
+
+/*
+ * Log macro that allows you to specify a number for the priority.
+ */
+#ifndef FBLOG_PRI
+#define FBLOG_PRI(priority, tag, ...) fb_printLog(priority, tag, __VA_ARGS__)
+#endif
+
+/*
+ * Log macro that allows you to pass in a varargs ("args" is a va_list).
+ */
+#ifndef FBLOG_PRI_VA
+#define FBLOG_PRI_VA(priority, tag, fmt, args) \
+  fb_vprintLog(priority, NULL, tag, fmt, args)
+#endif
+
+/*
+ * Conditional given a desired logging priority and tag.
+ */
+#ifndef IF_FBLOG
+#define IF_FBLOG(priority, tag) if (fb_testLog(ANDROID_##priority, tag))
+#endif
+
+typedef void (*LogHandler)(int priority, const char* tag, const char* message);
+FBEXPORT void setLogHandler(LogHandler logHandler);
+
+/*
+ * ===========================================================================
+ *
+ * The stuff in the rest of this file should not be used directly.
+ */
+FBEXPORT int fb_printLog(int prio, const char* tag, const char* fmt, ...)
+#if defined(__GNUC__)
+    __attribute__((format(printf, 3, 4)))
+#endif
+    ;
+
+#define fb_vprintLog(prio, cond, tag, fmt...) \
+  __android_log_vprint(prio, tag, fmt)
+
+#define fb_printAssert(cond, tag, fmt...) __android_log_assert(cond, tag, fmt)
+
+#define fb_writeLog(prio, tag, text) __android_log_write(prio, tag, text)
+
+#define fb_bWriteLog(tag, payload, len) __android_log_bwrite(tag, payload, len)
+#define fb_btWriteLog(tag, type, payload, len) \
+  __android_log_btwrite(tag, type, payload, len)
+
+#define fb_testLog(prio, tag) (1)
+
+/*
+ * FB extensions
+ */
+void logPrintByDelims(int priority, const char* tag, const char* delims,
+                      const char* msg, ...);
+
+#ifdef __cplusplus
+}
+#endif
--- a/lib/fb/src/main/cpp/include/lyra/lyra.h
+++ b/lib/fb/src/main/cpp/include/lyra/lyra.h
@@ -7,9 +7,12 @@
 #pragma once

 #include <iomanip>
+#include <iostream>
 #include <string>
 #include <vector>

+#include <fb/visibility.h>
+
 namespace facebook {
 namespace lyra {

@@ -17,21 +20,17 @@ constexpr size_t kDefaultLimit = 64;

 using InstructionPointer = const void*;

-class StackTraceElement {
+class FBEXPORT StackTraceElement {
 public:
  StackTraceElement(InstructionPointer absoluteProgramCounter,
                    InstructionPointer libraryBase,
-                    InstructionPointer functionAddress,
-                    std::string libraryName,
+                    InstructionPointer functionAddress, std::string libraryName,
                    std::string functionName)
      : absoluteProgramCounter_{absoluteProgramCounter},
        libraryBase_{libraryBase},
        functionAddress_{functionAddress},
        libraryName_{std::move(libraryName)},
-        functionName_{std::move(functionName)},
-        hasBuildId_{false},
-        buildId_{}
-  {}
+        functionName_{std::move(functionName)} {}

  InstructionPointer libraryBase() const noexcept { return libraryBase_; }

@@ -68,28 +67,14 @@ class StackTraceElement {
    return absoluteabsoluteProgramCounter - absoluteSymbol;
  }

-  std::string buildId() const;
 private:
  const InstructionPointer absoluteProgramCounter_;
  const InstructionPointer libraryBase_;
  const InstructionPointer functionAddress_;
  const std::string libraryName_;
  const std::string functionName_;
-
-  mutable bool hasBuildId_;
-  mutable std::string buildId_;
 };

-/**
- * If a library identifier function is set, it is passed a libraryName
- * for the frame, and returns a library build id string, which will be
- * included in the logged stack trace.  The most common use for this
- * will be correlating stack traces with breakpad identifiers.
- */
-typedef std::string (*LibraryIdentifierFunctionType)(const std::string&);
-
-void setLibraryIdentifierFunction(LibraryIdentifierFunctionType func);
-
 /**
 * Populate the vector with the current stack trace
 *
@@ -106,7 +91,8 @@ void setLibraryIdentifierFunction(LibraryIdentifierFunctionType func);
 *
 * @param skip The number of frames to skip before capturing the trace
 */
-void getStackTrace(std::vector<InstructionPointer>& stackTrace, size_t skip = 0);
+FBEXPORT void getStackTrace(std::vector<InstructionPointer>& stackTrace,
+                            size_t skip = 0);

 /**
 * Creates a vector and populates it with the current stack trace
@@ -122,7 +108,7 @@ void getStackTrace(std::vector<InstructionPointer>& stackTrace, size_t skip = 0)
 *
 * @limit The maximum number of frames captured
 */
-inline std::vector<InstructionPointer> getStackTrace(
+FBEXPORT inline std::vector<InstructionPointer> getStackTrace(
    size_t skip = 0,
    size_t limit = kDefaultLimit) {
  auto stackTrace = std::vector<InstructionPointer>{};
@@ -139,15 +125,15 @@ inline std::vector<InstructionPointer> getStackTrace(
 *
 * @param stackTrace The input stack trace
 */
-void getStackTraceSymbols(std::vector<StackTraceElement>& symbols,
-                          const std::vector<InstructionPointer>& trace);
+FBEXPORT void getStackTraceSymbols(std::vector<StackTraceElement>& symbols,
+                                   const std::vector<InstructionPointer>& trace);

 /**
 * Symbolicates a stack trace into a new vector
 *
 * @param stackTrace The input stack trace
 */
-inline std::vector<StackTraceElement> getStackTraceSymbols(
+FBEXPORT inline std::vector<StackTraceElement> getStackTraceSymbols(
    const std::vector<InstructionPointer>& trace) {
  auto symbols = std::vector<StackTraceElement>{};
  getStackTraceSymbols(symbols, trace);
@@ -166,7 +152,7 @@ inline std::vector<StackTraceElement> getStackTraceSymbols(
 *
 * @param limit The maximum number of frames captured
 */
-inline std::vector<StackTraceElement> getStackTraceSymbols(
+FBEXPORT inline std::vector<StackTraceElement> getStackTraceSymbols(
    size_t skip = 0,
    size_t limit = kDefaultLimit) {
  return getStackTraceSymbols(getStackTrace(skip + 1, limit));
@@ -175,21 +161,12 @@ inline std::vector<StackTraceElement> getStackTraceSymbols(
 /**
 * Formatting a stack trace element
 */
-std::ostream& operator<<(std::ostream& out, const StackTraceElement& elm);
+FBEXPORT std::ostream& operator<<(std::ostream& out, const StackTraceElement& elm);

 /**
 * Formatting a stack trace
 */
-std::ostream& operator<<(std::ostream& out,
-                         const std::vector<StackTraceElement>& trace);
-
-/**
- * Log stack trace
- *
- * Makes it possible to log a trace without using a temporary stream when the
- * underlying log API is not stream based.
- */
-void logStackTrace(const std::vector<StackTraceElement>& trace);
-
+FBEXPORT std::ostream& operator<<(std::ostream& out,
+                                  const std::vector<StackTraceElement>& trace);
 }
 }
--- a/lib/fb/src/main/cpp/include/fb/noncopyable.h
+++ b/lib/fb/src/main/cpp/include/fb/noncopyable.h
@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+namespace facebook {
+
+struct noncopyable {
+  noncopyable(const noncopyable&) = delete;
+  noncopyable& operator=(const noncopyable&) = delete;
+protected:
+  noncopyable() = default;
+};
+
+}
--- a/lib/fb/src/main/cpp/include/fb/nonmovable.h
+++ b/lib/fb/src/main/cpp/include/fb/nonmovable.h
@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+namespace facebook {
+
+struct nonmovable {
+  nonmovable(nonmovable&&) = delete;
+  nonmovable& operator=(nonmovable&&) = delete;
+protected:
+  nonmovable() = default;
+};
+
+}
--- a/lib/fb/src/main/java/com/facebook/jni/HybridClassBase.java
+++ b/lib/fb/src/main/java/com/facebook/jni/HybridClassBase.java
@@ -4,9 +4,6 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-package com.facebook.jni;
+#pragma once

-import com.facebook.jni.annotations.DoNotStrip;
-
-@DoNotStrip
-public abstract class HybridClassBase extends HybridData {}
+#define FBEXPORT __attribute__((visibility("default")))
--- a/lib/fb/src/main/cpp/include/fbjni/JThread.h
+++ b/lib/fb/src/main/cpp/include/fbjni/JThread.h
@@ -1,56 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include <fbjni/fbjni.h>
-#include <fbjni/NativeRunnable.h>
-
-namespace facebook {
-namespace jni {
-
-class JThread : public JavaClass<JThread> {
- public:
-  static constexpr const char* kJavaDescriptor = "Ljava/lang/Thread;";
-
-  void start() {
-    static const auto method = javaClassStatic()->getMethod<void()>("start");
-    method(self());
-  }
-
-  void join() {
-    static const auto method = javaClassStatic()->getMethod<void()>("join");
-    method(self());
-  }
-
-  static local_ref<JThread> create(std::function<void()>&& runnable) {
-    auto jrunnable = JNativeRunnable::newObjectCxxArgs(std::move(runnable));
-    return newInstance(static_ref_cast<JRunnable::javaobject>(jrunnable));
-  }
-
-  static local_ref<JThread> create(std::function<void()>&& runnable, std::string&& name) {
-    auto jrunnable = JNativeRunnable::newObjectCxxArgs(std::move(runnable));
-    return newInstance(static_ref_cast<JRunnable::javaobject>(jrunnable), make_jstring(std::move(name)));
-  }
-
-  static local_ref<JThread> getCurrent() {
-    static const auto method = javaClassStatic()->getStaticMethod<local_ref<JThread>()>("currentThread");
-    return method(javaClassStatic());
-  }
-
-  int getPriority() {
-    static const auto method = getClass()->getMethod<jint()>("getPriority");
-    return method(self());
-  }
-
-  void setPriority(int priority) {
-    static const auto method = getClass()->getMethod<void(int)>("setPriority");
-    method(self(), priority);
-  }
-};
-
-}
-}
--- a/lib/fb/src/main/cpp/include/fbjni/ReadableByteChannel.h
+++ b/lib/fb/src/main/cpp/include/fbjni/ReadableByteChannel.h
@@ -1,22 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include <fbjni/fbjni.h>
-#include <fbjni/ByteBuffer.h>
-
-namespace facebook {
-namespace jni {
-
-class JReadableByteChannel : public JavaClass<JReadableByteChannel> {
-public:
-  static constexpr const char* kJavaDescriptor = "Ljava/nio/channels/ReadableByteChannel;";
-
-  int read(alias_ref<JByteBuffer> dest) const;
-};
-
-}}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/JWeakReference.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/JWeakReference.h
@@ -1,39 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include "CoreClasses.h"
-
-namespace facebook {
-namespace jni {
-
-/**
- * Wrap Java's WeakReference instead of using JNI WeakGlobalRefs.
- * A WeakGlobalRef can yield a strong reference even after the object has been
-  * finalized. See comment in the djinni library.
- * https://github.com/dropbox/djinni/blob/master/support-lib/jni/djinni_support.hpp
- */
-template<typename T = jobject>
-class JWeakReference : public JavaClass<JWeakReference<T>> {
-
- typedef JavaClass<JWeakReference<T>> JavaBase_;
-
- public:
-  static constexpr const char* kJavaDescriptor = "Ljava/lang/ref/WeakReference;";
-
-  static local_ref<JWeakReference<T>> newInstance(alias_ref<T> object) {
-    return JavaBase_::newInstance(static_ref_cast<jobject>(object));
-  }
-
-  local_ref<T> get() const {
-    static const auto method = JavaBase_::javaClassStatic()->template getMethod<jobject()>("get");
-    return static_ref_cast<T>(method(JavaBase_::self()));
-  }
-};
-
-}
-}
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Log.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Log.h
@@ -1,67 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-/** @file ALog.h
- *
- *  Very simple (android only) logging. Define LOG_TAG to enable the macros.
- */
-
-#pragma once
-
-#ifdef __ANDROID__
-
-#include <android/log.h>
-
-namespace facebook {
-namespace jni {
-namespace log_ {
-// the weird name of this namespace is to avoid a conflict with the
-// function named log.
-
-inline void loge(const char* tag, const char* msg) noexcept {
-  __android_log_write(ANDROID_LOG_ERROR, tag, msg);
-}
-
-template<typename... ARGS>
-inline void loge(const char* tag, const char* msg, ARGS... args) noexcept {
-  __android_log_print(ANDROID_LOG_ERROR, tag, msg, args...);
-}
-
-inline void logf(const char* tag, const char* msg) noexcept {
-  __android_log_write(ANDROID_LOG_FATAL, tag, msg);
-}
-
-template<typename... ARGS>
-inline void logf(const char* tag, const char* msg, ARGS... args) noexcept {
-  __android_log_print(ANDROID_LOG_FATAL, tag, msg, args...);
-}
-
-template<typename... ARGS>
-[[noreturn]]
-inline void logassert(const char* tag, const char* msg, ARGS... args) noexcept {
-  __android_log_assert(0, tag, msg, args...);
-}
-
-
-#ifdef LOG_TAG
-# define FBJNI_LOGE(...) ::facebook::jni::log_::loge(LOG_TAG, __VA_ARGS__)
-# define FBJNI_LOGF(...) ::facebook::jni::log_::logf(LOG_TAG, __VA_ARGS__)
-# define FBJNI_ASSERT(cond) do { if (!(cond)) ::facebook::jni::log_::logassert(LOG_TAG, "%s", #cond); } while(0)
-#else
-# define FBJNI_LOGE(...) ::facebook::jni::log_::loge("log", __VA_ARGS__)
-# define FBJNI_LOGF(...) ::facebook::jni::log_::logf("log", __VA_ARGS__)
-# define FBJNI_ASSERT(cond) do { if (!(cond)) ::facebook::jni::log_::logassert("log", "%s", #cond); } while(0)
-#endif
-
-}}}
-
-#else
-#include <stdlib.h>
-
-# define FBJNI_LOGE(...) ((void)0)
-# define FBJNI_LOGF(...) (abort())
-# define FBJNI_ASSERT(cond) ((void)0)
-#endif
--- a/lib/fb/src/main/cpp/include/fbjni/detail/Registration-inl.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/Registration-inl.h
@@ -1,166 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include "Exceptions.h"
-#include "Hybrid.h"
-
-namespace facebook {
-namespace jni {
-
-namespace detail {
-
-#ifdef __i386__
-// X86 ABI forces 16 byte stack allignment on calls. Unfortunately
-// sometimes Dalvik chooses not to obey the ABI:
-// - https://code.google.com/p/android/issues/detail?id=61012
-// - https://android.googlesource.com/platform/ndk/+/81696d2%5E!/
-// Therefore, we tell the compiler to re-align the stack on entry
-// to our JNI functions.
-#define JNI_ENTRY_POINT __attribute__((force_align_arg_pointer))
-#else
-#define JNI_ENTRY_POINT
-#endif
-
-template <typename R>
-struct CreateDefault {
-  static R create() {
-    return R{};
-  }
-};
-
-template <>
-struct CreateDefault<void> {
-  static void create() {}
-};
-
-template <typename R>
-using Converter = Convert<typename std::decay<R>::type>;
-
-template <typename F, F func, typename R, typename... Args>
-struct WrapForVoidReturn {
-  static typename Converter<R>::jniType call(Args&&... args) {
-    return Converter<R>::toJniRet(func(std::forward<Args>(args)...));
-  }
-};
-
-template <typename F, F func, typename... Args>
-struct WrapForVoidReturn<F, func, void, Args...> {
-  static void call(Args&&... args) {
-    func(std::forward<Args>(args)...);
-  }
-};
-
-// registration wrapper for legacy JNI-style functions
-template<typename F, F func, typename C, typename R, typename... Args>
-struct BareJniWrapper {
-  JNI_ENTRY_POINT static R call(JNIEnv* env, jobject obj, Args... args) {
-    detail::JniEnvCacher jec(env);
-    try {
-      return (*func)(env, static_cast<JniType<C>>(obj), args...);
-    } catch (...) {
-      translatePendingCppExceptionToJavaException();
-      return CreateDefault<R>::create();
-    }
-  }
-};
-
-// registration wrappers for functions, with autoconversion of arguments.
-template<typename F, F func, typename C, typename R, typename... Args>
-struct FunctionWrapper {
-  using jniRet = typename Converter<R>::jniType;
-  JNI_ENTRY_POINT static jniRet call(JNIEnv* env, jobject obj, typename Converter<Args>::jniType... args) {
-    detail::JniEnvCacher jec(env);
-    try {
-      return WrapForVoidReturn<F, func, R, JniType<C>, Args...>::call(
-          static_cast<JniType<C>>(obj), Converter<Args>::fromJni(args)...);
-    } catch (...) {
-      translatePendingCppExceptionToJavaException();
-      return CreateDefault<jniRet>::create();
-    }
-  }
-};
-
-// registration wrappers for non-static methods, with autoconvertion of arguments.
-template<typename M, M method, typename C, typename R, typename... Args>
-struct MethodWrapper {
-  using jhybrid = typename C::jhybridobject;
-  static R dispatch(alias_ref<jhybrid> ref, Args&&... args) {
-    try {
-      // This is usually a noop, but if the hybrid object is a
-      // base class of other classes which register JNI methods,
-      // this will get the right type for the registered method.
-      auto cobj = static_cast<C*>(ref->cthis());
-      return (cobj->*method)(std::forward<Args>(args)...);
-    } catch (const std::exception& ex) {
-      C::mapException(ex);
-      throw;
-    }
-  }
-
-  JNI_ENTRY_POINT static typename Converter<R>::jniType call(
-      JNIEnv* env, jobject obj, typename Converter<Args>::jniType... args) {
-    return FunctionWrapper<R(*)(alias_ref<jhybrid>, Args&&...), dispatch, jhybrid, R, Args...>::call(env, obj, args...);
-  }
-};
-
-template<typename F, F func, typename C, typename R, typename... Args>
-inline NativeMethodWrapper* exceptionWrapJNIMethod(R (*)(JNIEnv*, C, Args... args)) {
-  // This intentionally erases the real type; JNI will do it anyway
-  return reinterpret_cast<NativeMethodWrapper*>(&(BareJniWrapper<F, func, C, R, Args...>::call));
-}
-
-template<typename F, F func, typename C, typename R, typename... Args>
-inline NativeMethodWrapper* exceptionWrapJNIMethod(R (*)(alias_ref<C>, Args... args)) {
-  // This intentionally erases the real type; JNI will do it anyway
-  return reinterpret_cast<NativeMethodWrapper*>(&(FunctionWrapper<F, func, C, R, Args...>::call));
-}
-
-template<typename M, M method, typename C, typename R, typename... Args>
-inline NativeMethodWrapper* exceptionWrapJNIMethod(R (C::*method0)(Args... args)) {
-  (void)method0;
-  // This intentionally erases the real type; JNI will do it anyway
-  return reinterpret_cast<NativeMethodWrapper*>(&(MethodWrapper<M, method, C, R, Args...>::call));
-}
-
-template<typename R, typename C, typename... Args>
-inline std::string makeDescriptor(R (*)(JNIEnv*, C, Args... args)) {
-  return jmethod_traits<R(Args...)>::descriptor();
-}
-
-template<typename R, typename C, typename... Args>
-inline std::string makeDescriptor(R (*)(alias_ref<C>, Args... args)) {
-  return jmethod_traits_from_cxx<R(Args...)>::descriptor();
-}
-
-template<typename R, typename C, typename... Args>
-inline std::string makeDescriptor(R (C::*)(Args... args)) {
-  return jmethod_traits_from_cxx<R(Args...)>::descriptor();
-}
-
-template<typename R, typename ...Args>
-template<R(*func)(Args...)>
-JNI_ENTRY_POINT R CriticalMethod<R(*)(Args...)>::call(alias_ref<jclass>, Args... args) noexcept {
-  static_assert(
-    IsJniPrimitive<R>() || std::is_void<R>(),
-    "Critical Native Methods may only return primitive JNI types, or void.");
-  static_assert(
-    AreJniPrimitives<Args...>(),
-    "Critical Native Methods may only use primitive JNI types as parameters");
-
-  return func(std::forward<Args>(args)...);
-}
-
-template<typename R, typename ...Args>
-template<R(*func)(Args...)>
-inline std::string CriticalMethod<R(*)(Args...)>::desc() {
-  return makeDescriptor(call<func>);
-}
-
-}
-
-}}
--- a/lib/fb/src/main/cpp/include/fbjni/fbjni.h
+++ b/lib/fb/src/main/cpp/include/fbjni/fbjni.h
@@ -1,22 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include <jni.h>
-
-#include <fbjni/detail/Environment.h>
-#include <fbjni/detail/Log.h>
-#include <fbjni/detail/Common.h>
-#include <fbjni/detail/Exceptions.h>
-#include <fbjni/detail/ReferenceAllocators.h>
-#include <fbjni/detail/References.h>
-#include <fbjni/detail/Meta.h>
-#include <fbjni/detail/CoreClasses.h>
-#include <fbjni/detail/Iterator.h>
-#include <fbjni/detail/Hybrid.h>
-#include <fbjni/detail/Registration.h>
-#include <fbjni/detail/JWeakReference.h>
--- a/lib/fb/src/main/cpp/include/jni/Countable.h
+++ b/lib/fb/src/main/cpp/include/jni/Countable.h
@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <jni.h>
+
+#include <fb/Countable.h>
+#include <fb/RefPtr.h>
+#include <fb/visibility.h>
+
+namespace facebook {
+namespace jni {
+
+FBEXPORT const RefPtr<Countable>& countableFromJava(JNIEnv* env, jobject obj);
+
+template <typename T> RefPtr<T> extractRefPtr(JNIEnv* env, jobject obj) {
+  return static_cast<RefPtr<T>>(countableFromJava(env, obj));
+}
+
+template <typename T> RefPtr<T> extractPossiblyNullRefPtr(JNIEnv* env, jobject obj) {
+  return obj ? extractRefPtr<T>(env, obj) : nullptr;
+}
+
+FBEXPORT void setCountableForJava(JNIEnv* env, jobject obj, RefPtr<Countable>&& countable);
+
+void CountableOnLoad(JNIEnv* env);
+
+} }
+
--- a/lib/fb/src/main/cpp/include/jni/GlobalReference.h
+++ b/lib/fb/src/main/cpp/include/jni/GlobalReference.h
@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <memory>
+#include <type_traits>
+
+#include <jni.h>
+
+#include <fb/Environment.h>
+
+namespace facebook { namespace jni {
+
+template<typename T>
+class GlobalReference {
+  static_assert(std::is_convertible<T, jobject>::value,
+                "GlobalReference<T> instantiated with type that is not "
+                "convertible to jobject");
+
+ public:
+  explicit GlobalReference(T globalReference) :
+    reference_(globalReference? Environment::current()->NewGlobalRef(globalReference) : nullptr) {
+  }
+
+  ~GlobalReference() {
+    reset();
+  }
+
+  GlobalReference() :
+    reference_(nullptr) {
+  }
+
+  // enable move constructor and assignment
+  GlobalReference(GlobalReference&& rhs) :
+    reference_(std::move(rhs.reference_)) {
+    rhs.reference_ = nullptr;
+  }
+
+  GlobalReference& operator=(GlobalReference&& rhs) {
+    if (this != &rhs) {
+      reset();
+      reference_ = std::move(rhs.reference_);
+      rhs.reference_ = nullptr;
+    }
+    return *this;
+  }
+
+  GlobalReference(const GlobalReference<T>& rhs) :
+    reference_{} {
+    reset(rhs.get());
+  }
+
+  GlobalReference& operator=(const GlobalReference<T>& rhs) {
+    if (this == &rhs) {
+      return *this;
+    }
+    reset(rhs.get());
+    return *this;
+  }
+
+  explicit operator bool() const {
+    return (reference_ != nullptr);
+  }
+
+  T get() const {
+    return reinterpret_cast<T>(reference_);
+  }
+
+  void reset(T globalReference = nullptr) {
+    if (reference_) {
+      Environment::current()->DeleteGlobalRef(reference_);
+    }
+    if (globalReference) {
+      reference_ = Environment::current()->NewGlobalRef(globalReference);
+    } else {
+      reference_ = nullptr;
+    }
+  }
+
+ private:
+  jobject reference_;
+};
+
+}}
--- a/lib/fb/src/main/cpp/include/jni/LocalReference.h
+++ b/lib/fb/src/main/cpp/include/jni/LocalReference.h
@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <memory>
+#include <type_traits>
+
+#include <jni.h>
+
+#include <fb/Environment.h>
+
+namespace facebook {
+namespace jni {
+
+template<class T>
+struct LocalReferenceDeleter {
+  static_assert(std::is_convertible<T, jobject>::value,
+    "LocalReferenceDeleter<T> instantiated with type that is not convertible to jobject");
+  void operator()(T localReference) {
+    if (localReference != nullptr) {
+      Environment::current()->DeleteLocalRef(localReference);
+    }
+  } 
+ };
+
+template<class T>
+using LocalReference =
+  std::unique_ptr<typename std::remove_pointer<T>::type, LocalReferenceDeleter<T>>;
+
+} }
--- a/lib/fb/src/main/cpp/include/fbjni/detail/utf8.h
+++ b/lib/fb/src/main/cpp/include/fbjni/detail/utf8.h
@@ -10,6 +10,8 @@

 #include <jni.h>

+#include <fb/visibility.h>
+
 namespace facebook {
 namespace jni {

@@ -40,18 +42,28 @@ std::string utf16toUTF8(const uint16_t* utf16Bytes, size_t len) noexcept;
 //  - http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html
 //  - https://docs.oracle.com/javase/6/docs/api/java/io/DataInput.html#modified-utf-8

-// JString to UTF16 extractor using RAII idiom. Note that the
-// ctor/dtor use GetStringCritical/ReleaseStringCritical, so this
-// class is subject to the restrictions imposed by those functions.
+class FBEXPORT LocalString {
+public:
+  // Assumes UTF8 encoding and make a required convertion to modified UTF-8 when the string
+  // contains unicode supplementary characters.
+  explicit LocalString(const std::string& str);
+  explicit LocalString(const char* str);
+  jstring string() const {
+    return m_string;
+  }
+  ~LocalString();
+private:
+  jstring m_string;
+};
+
+// JString to UTF16 extractor using RAII idiom
 class JStringUtf16Extractor {
 public:
  JStringUtf16Extractor(JNIEnv* env, jstring javaString)
  : env_(env)
  , javaString_(javaString)
-  , length_(0)
  , utf16String_(nullptr) {
    if (env_ && javaString_) {
-      length_ = env_->GetStringLength(javaString_);
      utf16String_ = env_->GetStringCritical(javaString_, nullptr);
    }
  }
@@ -62,20 +74,18 @@ public:
    }
  }

-  const jsize length() const {
-    return length_;
-  }
-
-  const jchar* chars() const {
+  operator const jchar* () const {
    return utf16String_;
  }

 private:
  JNIEnv* env_;
  jstring javaString_;
-  jsize length_;
  const jchar* utf16String_;
 };

-}
-}
+// The string from JNI is converted to standard UTF-8 if the string contains supplementary
+// characters.
+FBEXPORT std::string fromJString(JNIEnv* env, jstring str);
+
+} }
--- a/lib/fb/src/main/cpp/include/jni/Registration.h
+++ b/lib/fb/src/main/cpp/include/jni/Registration.h
@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <jni.h>
+#include <initializer_list>
+#include <fb/assert.h>
+
+namespace facebook {
+namespace jni {
+
+static inline void registerNatives(JNIEnv* env, jclass cls, std::initializer_list<JNINativeMethod> methods) {
+  auto result = env->RegisterNatives(cls, methods.begin(), methods.size());
+  FBASSERT(result == 0);
+}
+
+static inline void registerNatives(JNIEnv* env, const char* cls, std::initializer_list<JNINativeMethod> list) {
+  registerNatives(env, env->FindClass(cls), list);
+}
+
+} }
--- a/lib/fb/src/main/cpp/include/jni/WeakReference.h
+++ b/lib/fb/src/main/cpp/include/jni/WeakReference.h
@@ -0,0 +1,52 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+#include <string>
+#include <jni.h>
+#include <fb/noncopyable.h>
+#include <fb/Countable.h>
+#include <fb/visibility.h>
+
+
+namespace facebook {
+namespace jni {
+
+class FBEXPORT WeakReference : public Countable {
+public:
+  typedef RefPtr<WeakReference> Ptr;
+  WeakReference(jobject strongRef);
+  ~WeakReference();
+  jweak weakRef() {
+    return m_weakReference;
+  }
+
+private:
+  jweak m_weakReference;
+};
+
+// This class is intended to take a weak reference and turn it into a strong
+// local reference. Consequently, it should only be allocated on the stack.
+class FBEXPORT ResolvedWeakReference : public noncopyable {
+public:
+  ResolvedWeakReference(jobject weakRef);
+  ResolvedWeakReference(const RefPtr<WeakReference>& weakRef);
+  ~ResolvedWeakReference();
+
+  operator jobject () {
+    return m_strongReference;
+  }
+
+  explicit operator bool () {
+    return m_strongReference != nullptr;
+  }
+
+private:
+  jobject m_strongReference;
+};
+
+} }
+
--- a/lib/fb/src/main/cpp/include/jni/jni_helpers.h
+++ b/lib/fb/src/main/cpp/include/jni/jni_helpers.h
@@ -0,0 +1,136 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <jni.h>
+
+#include <fb/visibility.h>
+
+namespace facebook {
+
+/**
+ * Instructs the JNI environment to throw an exception.
+ *
+ * @param pEnv JNI environment
+ * @param szClassName class name to throw
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwException(JNIEnv* pEnv, const char* szClassName, const char* szFmt, va_list va_args);
+
+/**
+ * Instructs the JNI environment to throw a NoClassDefFoundError.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwNoClassDefError(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw a RuntimeException.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwRuntimeException(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw a IllegalArgumentException.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwIllegalArgumentException(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw a IllegalStateException.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwIllegalStateException(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw an IOException.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwIOException(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw an AssertionError.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwAssertionError(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Instructs the JNI environment to throw an OutOfMemoryError.
+ *
+ * @param pEnv JNI environment
+ * @param szFmt sprintf-style format string
+ * @param ... sprintf-style args
+ * @return 0 on success; a negative value on failure
+ */
+FBEXPORT jint throwOutOfMemoryError(JNIEnv* pEnv, const char* szFmt, ...);
+
+/**
+ * Finds the specified class. If it's not found, instructs the JNI environment to throw an
+ * exception.
+ *
+ * @param pEnv JNI environment
+ * @param szClassName the classname to find in JNI format (e.g. "java/lang/String")
+ * @return the class or NULL if not found (in which case a pending exception will be queued). This
+ *     returns a global reference (JNIEnv::NewGlobalRef).
+ */
+FBEXPORT jclass findClassOrThrow(JNIEnv *pEnv, const char* szClassName);
+
+/**
+ * Finds the specified field of the specified class. If it's not found, instructs the JNI
+ * environment to throw an exception.
+ *
+ * @param pEnv JNI environment
+ * @param clazz the class to lookup the field in
+ * @param szFieldName the name of the field to find
+ * @param szSig the signature of the field
+ * @return the field or NULL if not found (in which case a pending exception will be queued)
+ */
+FBEXPORT jfieldID getFieldIdOrThrow(JNIEnv* pEnv, jclass clazz, const char* szFieldName, const char* szSig);
+
+/**
+ * Finds the specified method of the specified class. If it's not found, instructs the JNI
+ * environment to throw an exception.
+ *
+ * @param pEnv JNI environment
+ * @param clazz the class to lookup the method in
+ * @param szMethodName the name of the method to find
+ * @param szSig the signature of the method
+ * @return the method or NULL if not found (in which case a pending exception will be queued)
+ */
+FBEXPORT jmethodID getMethodIdOrThrow(
+    JNIEnv* pEnv,
+    jclass clazz,
+    const char* szMethodName,
+    const char* szSig);
+
+} // namespace facebook
+
--- a/lib/fb/src/main/cpp/include/lyra/lyra_exceptions.h
+++ b/lib/fb/src/main/cpp/include/lyra/lyra_exceptions.h
@@ -1,84 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the LICENSE
- * file in the root directory of this source tree.
- */
-#pragma once
-
-#include <exception>
-#include <typeinfo>
-#include <vector>
-
-#include <lyra/lyra.h>
-
-namespace facebook {
-namespace lyra {
-
-namespace detail {
-  struct ExceptionTraceHolder {
-    ExceptionTraceHolder();
-    // Need some virtual function to make this a polymorphic type.
-    virtual ~ExceptionTraceHolder();
-    ExceptionTraceHolder(const ExceptionTraceHolder&) = delete;
-    ExceptionTraceHolder(ExceptionTraceHolder&&) = default;
-
-    std::vector<InstructionPointer> stackTrace_;
-  };
-
-  template <typename E, bool hasTraceHolder>
-  struct Holder : E, ExceptionTraceHolder {
-    Holder(E&& e) : E{std::forward<E>(e)}, ExceptionTraceHolder{} {}
-  };
-  template <typename E>
-  struct Holder<E, true> : E {
-    Holder(E&& e) : E{std::forward<E>(e)} {}
-  };
-}
-
-/**
- * Retrieves the stack trace of an exception
- */
-const std::vector<InstructionPointer>& getExceptionTrace(std::exception_ptr ptr);
-
-/**
- * Throw an exception and store the stack trace. This works like
- * std::throw_with_nested in that it will actually throw a type that is
- * publicly derived from both E and detail::ExceptionTraceHolder.
- */
-template <class E>
-[[noreturn]] void fbthrow(E&& exception) {
-  throw detail::Holder<E, std::is_base_of<detail::ExceptionTraceHolder, E>::value>{std::forward<E>(exception)};
-}
-
-/**
- * Ensure that a terminate handler that logs traces is installed.
- * setLibraryIdentifierFunction should be called first if the stack
- * trace should log build ids for libraries.
- */
-void ensureRegisteredTerminateHandler();
-
-/**
- * Helper to convert an exception to a string
- */
-std::string toString(std::exception_ptr exceptionPointer);
-
-/**
- * lyra's cxa_throw will delegate to the original cxa throw. That pointer must
- * be set before lyra::cxa_throw is called.
- *
- * One example use would be to statically compile against something that overrides __cxa_throw.
- * That would look something like:
- *
- * [[noreturn]] void __cxa_throw(void* obj, const std::type_info* type, void (*destructor) (void*)) {
- *   static auto initializer = lyra::original_cxa_throw = lookupOriginalCxaThrow();
- *   lyra::cxa_throw(obj, type, destructor);
- * }
- */
-[[gnu::noreturn]] extern void (*original_cxa_throw)(void*, const std::type_info*, void (*) (void*));
-[[noreturn]] void cxa_throw(void* obj, const std::type_info* type, void (*destructor) (void *));
-
-void enableCxaThrowHookBacktraces(bool enable);
-
-}
-}
--- a/lib/fb/src/main/cpp/jni/ByteBuffer.cpp
+++ b/lib/fb/src/main/cpp/jni/ByteBuffer.cpp
@@ -4,51 +4,21 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-#include <fbjni/ByteBuffer.h>
+#include <fb/fbjni/ByteBuffer.h>

 #include <stdexcept>

+#include <fb/fbjni/References.h>
+
 namespace facebook {
 namespace jni {

-void JBuffer::rewind() const {
-  static auto meth = javaClassStatic()->getMethod<alias_ref<JBuffer>()>("rewind");
-  meth(self());
+namespace {
+local_ref<JByteBuffer> createEmpty() {
+  static auto cls = JByteBuffer::javaClassStatic();
+  static auto meth = cls->getStaticMethod<JByteBuffer::javaobject(int)>("allocateDirect");
+  return meth(cls, 0);
 }
-
-void* JBuffer::getDirectAddress() const {
-  if (!self()) {
-    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
-  }
-  void* addr = Environment::current()->GetDirectBufferAddress(self());
-  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
-  if (!addr) {
-    throw std::runtime_error(
-        isDirect() ?
-          "Attempt to get direct bytes of non-direct buffer." :
-          "Error getting direct bytes of buffer.");
-  }
-  return addr;
-}
-
-size_t JBuffer::getDirectCapacity() const {
-  if (!self()) {
-    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
-  }
-  int size = Environment::current()->GetDirectBufferCapacity(self());
-  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
-  if (size < 0) {
-    throw std::runtime_error(
-        isDirect() ?
-          "Attempt to get direct size of non-direct buffer." :
-          "Error getting direct size of buffer.");
-  }
-  return static_cast<size_t>(size);
-}
-
-bool JBuffer::isDirect() const {
-  static auto meth = javaClassStatic()->getMethod<jboolean()>("isDirect");
-  return meth(self());
 }

 local_ref<JByteBuffer> JByteBuffer::wrapBytes(uint8_t* data, size_t size) {
@@ -56,7 +26,7 @@ local_ref<JByteBuffer> JByteBuffer::wrapBytes(uint8_t* data, size_t size) {
  // dalvik returns an invalid result and Android's art aborts if size == 0.
  // Workaround this by using a slow path through Java in that case.
  if (!size) {
-    return allocateDirect(0);
+    return createEmpty();
  }
  auto res = adopt_local(static_cast<javaobject>(Environment::current()->NewDirectByteBuffer(data, size)));
  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
@@ -66,10 +36,39 @@ local_ref<JByteBuffer> JByteBuffer::wrapBytes(uint8_t* data, size_t size) {
  return res;
 }

-local_ref<JByteBuffer> JByteBuffer::allocateDirect(jint size) {
-  static auto cls = JByteBuffer::javaClassStatic();
-  static auto meth = cls->getStaticMethod<JByteBuffer::javaobject(int)>("allocateDirect");
-  return meth(cls, size);
+uint8_t* JByteBuffer::getDirectBytes() const {
+  if (!self()) {
+    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
+  }
+  void* bytes = Environment::current()->GetDirectBufferAddress(self());
+  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
+  if (!bytes) {
+    throw std::runtime_error(
+        isDirect() ?
+          "Attempt to get direct bytes of non-direct byte buffer." :
+          "Error getting direct bytes of byte buffer.");
+  }
+  return static_cast<uint8_t*>(bytes);
+}
+
+size_t JByteBuffer::getDirectSize() const {
+  if (!self()) {
+    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
+  }
+  int size = Environment::current()->GetDirectBufferCapacity(self());
+  FACEBOOK_JNI_THROW_PENDING_EXCEPTION();
+  if (size < 0) {
+    throw std::runtime_error(
+        isDirect() ?
+          "Attempt to get direct size of non-direct byte buffer." :
+          "Error getting direct size of byte buffer.");
+  }
+  return static_cast<size_t>(size);
+}
+
+bool JByteBuffer::isDirect() const {
+  static auto meth = javaClassStatic()->getMethod<jboolean()>("isDirect");
+  return meth(self());
 }

 }}
--- a/lib/fb/src/main/cpp/jni/Countable.cpp
+++ b/lib/fb/src/main/cpp/jni/Countable.cpp
@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include <cstdint>
+#include <jni/Countable.h>
+#include <fb/Environment.h>
+#include <jni/Registration.h>
+
+namespace facebook {
+namespace jni {
+
+static jfieldID gCountableNativePtr;
+
+static RefPtr<Countable>* rawCountableFromJava(JNIEnv* env, jobject obj) {
+  FBASSERT(obj);
+  return reinterpret_cast<RefPtr<Countable>*>(env->GetLongField(obj, gCountableNativePtr));
+}
+
+const RefPtr<Countable>& countableFromJava(JNIEnv* env, jobject obj) {
+  FBASSERT(obj);
+  return *rawCountableFromJava(env, obj);
+}
+
+void setCountableForJava(JNIEnv* env, jobject obj, RefPtr<Countable>&& countable) {
+  int oldValue = env->GetLongField(obj, gCountableNativePtr);
+  FBASSERTMSGF(oldValue == 0, "Cannot reinitialize object; expected nullptr, got %x", oldValue);
+
+  FBASSERT(countable);
+  uintptr_t fieldValue = (uintptr_t) new RefPtr<Countable>(std::move(countable));
+  env->SetLongField(obj, gCountableNativePtr, fieldValue);
+}
+
+/**
+ * NB: THREAD SAFETY (this comment also exists at Countable.java)
+ *
+ * This method deletes the corresponding native object on whatever thread the method is called
+ * on. In the common case when this is called by Countable#finalize(), this will be called on the
+ * system finalizer thread. If you manually call dispose on the Java object, the native object 
+ * will be deleted synchronously on that thread.
+ */
+void dispose(JNIEnv* env, jobject obj) {
+  // Grab the pointer
+  RefPtr<Countable>* countable = rawCountableFromJava(env, obj);
+  if (!countable) {
+    // That was easy.
+    return;
+  }
+
+  // Clear out the old value to avoid double-frees
+  env->SetLongField(obj, gCountableNativePtr, 0);
+
+  delete countable;
+}
+
+void CountableOnLoad(JNIEnv* env) {
+  jclass countable = env->FindClass("com/facebook/jni/Countable");
+  gCountableNativePtr = env->GetFieldID(countable, "mInstance", "J");
+  registerNatives(env, countable, {
+    { "dispose", "()V", (void*) dispose },
+  });
+}
+
+} }
--- a/lib/fb/src/main/cpp/jni/Environment.cpp
+++ b/lib/fb/src/main/cpp/jni/Environment.cpp
@@ -0,0 +1,129 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include <pthread.h>
+#include <fb/log.h>
+#include <fb/StaticInitialized.h>
+#include <fb/ThreadLocal.h>
+#include <fb/Environment.h>
+#include <fb/fbjni/CoreClasses.h>
+#include <fb/fbjni/NativeRunnable.h>
+
+#include <functional>
+
+namespace facebook {
+namespace jni {
+
+namespace {
+StaticInitialized<ThreadLocal<JNIEnv>> g_env;
+JavaVM* g_vm = nullptr;
+
+struct JThreadScopeSupport : JavaClass<JThreadScopeSupport> {
+  static auto constexpr kJavaDescriptor = "Lcom/facebook/jni/ThreadScopeSupport;";
+
+  // These reinterpret_casts are a totally dangerous pattern. Don't use them. Use HybridData instead.
+  static void runStdFunction(std::function<void()>&& func) {
+    static auto method = javaClassStatic()->getStaticMethod<void(jlong)>("runStdFunction");
+    method(javaClassStatic(), reinterpret_cast<jlong>(&func));
+  }
+
+  static void runStdFunctionImpl(alias_ref<JClass>, jlong ptr) {
+    (*reinterpret_cast<std::function<void()>*>(ptr))();
+  }
+
+  static void OnLoad() {
+    // We need the javaClassStatic so that the class lookup is cached and that
+    // runStdFunction can be called from a ThreadScope-attached thread.
+    javaClassStatic()->registerNatives({
+        makeNativeMethod("runStdFunctionImpl", runStdFunctionImpl),
+      });
+  }
+};
+}
+
+/* static */
+JNIEnv* Environment::current() {
+  JNIEnv* env = g_env->get();
+  if ((env == nullptr) && (g_vm != nullptr)) {
+    if (g_vm->GetEnv((void**) &env, JNI_VERSION_1_6) != JNI_OK) {
+      FBLOGE("Error retrieving JNI Environment, thread is probably not attached to JVM");
+      // TODO(cjhopman): This should throw an exception.
+      env = nullptr;
+    } else {
+      g_env->reset(env);
+    }
+  }
+  return env;
+}
+
+/* static */
+void Environment::detachCurrentThread() {
+  auto env = g_env->get();
+  if (env) {
+    FBASSERT(g_vm);
+    g_vm->DetachCurrentThread();
+    g_env->reset();
+  }
+}
+
+struct EnvironmentInitializer {
+  EnvironmentInitializer(JavaVM* vm) {
+      FBASSERT(!g_vm);
+      FBASSERT(vm);
+      g_vm = vm;
+      g_env.initialize([] (void*) {});
+  }
+};
+
+/* static */
+void Environment::initialize(JavaVM* vm) {
+  static EnvironmentInitializer init(vm);
+}
+
+/* static */
+JNIEnv* Environment::ensureCurrentThreadIsAttached() {
+  auto env = g_env->get();
+  if (!env) {
+    FBASSERT(g_vm);
+    g_vm->AttachCurrentThread(&env, nullptr);
+    g_env->reset(env);
+  }
+  return env;
+}
+
+ThreadScope::ThreadScope()
+    : attachedWithThisScope_(false) {
+  JNIEnv* env = nullptr;
+  if (g_vm->GetEnv((void**) &env, JNI_VERSION_1_6) != JNI_EDETACHED) {
+    return;
+  }
+  env = facebook::jni::Environment::ensureCurrentThreadIsAttached();
+  FBASSERT(env);
+  attachedWithThisScope_ = true;
+}
+
+ThreadScope::~ThreadScope() {
+  if (attachedWithThisScope_) {
+    Environment::detachCurrentThread();
+  }
+}
+
+/* static */
+void ThreadScope::OnLoad() {
+  // These classes are required for ScopeWithClassLoader. Ensure they are looked up when loading.
+  JThreadScopeSupport::OnLoad();
+}
+
+/* static */
+void ThreadScope::WithClassLoader(std::function<void()>&& runnable) {
+  // TODO(cjhopman): If the classloader is already available in this scope, we
+  // shouldn't have to jump through java.
+  ThreadScope ts;
+  JThreadScopeSupport::runStdFunction(std::move(runnable));
+}
+
+} }
+
--- a/lib/fb/src/main/cpp/jni/Exceptions.cpp
+++ b/lib/fb/src/main/cpp/jni/Exceptions.cpp
@@ -0,0 +1,282 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include <fb/fbjni/CoreClasses.h>
+
+#include <fb/assert.h>
+#include <fb/log.h>
+
+#include <alloca.h>
+#include <cstdlib>
+#include <ios>
+#include <stdexcept>
+#include <stdio.h>
+#include <string>
+#include <system_error>
+
+#include <jni.h>
+
+
+namespace facebook {
+namespace jni {
+
+namespace {
+class JRuntimeException : public JavaClass<JRuntimeException, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Ljava/lang/RuntimeException;";
+
+  static local_ref<JRuntimeException> create(const char* str) {
+    return newInstance(make_jstring(str));
+  }
+
+  static local_ref<JRuntimeException> create() {
+    return newInstance();
+  }
+};
+
+class JIOException : public JavaClass<JIOException, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Ljava/io/IOException;";
+
+  static local_ref<JIOException> create(const char* str) {
+    return newInstance(make_jstring(str));
+  }
+};
+
+class JOutOfMemoryError : public JavaClass<JOutOfMemoryError, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Ljava/lang/OutOfMemoryError;";
+
+  static local_ref<JOutOfMemoryError> create(const char* str) {
+    return newInstance(make_jstring(str));
+  }
+};
+
+class JArrayIndexOutOfBoundsException : public JavaClass<JArrayIndexOutOfBoundsException, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Ljava/lang/ArrayIndexOutOfBoundsException;";
+
+  static local_ref<JArrayIndexOutOfBoundsException> create(const char* str) {
+    return newInstance(make_jstring(str));
+  }
+};
+
+class JUnknownCppException : public JavaClass<JUnknownCppException, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Lcom/facebook/jni/UnknownCppException;";
+
+  static local_ref<JUnknownCppException> create() {
+    return newInstance();
+  }
+
+  static local_ref<JUnknownCppException> create(const char* str) {
+    return newInstance(make_jstring(str));
+  }
+};
+
+class JCppSystemErrorException : public JavaClass<JCppSystemErrorException, JThrowable> {
+ public:
+  static auto constexpr kJavaDescriptor = "Lcom/facebook/jni/CppSystemErrorException;";
+
+  static local_ref<JCppSystemErrorException> create(const std::system_error& e) {
+    return newInstance(make_jstring(e.what()), e.code().value());
+  }
+};
+
+// Exception throwing & translating functions //////////////////////////////////////////////////////
+
+// Functions that throw Java exceptions
+
+void setJavaExceptionAndAbortOnFailure(alias_ref<JThrowable> throwable) {
+  auto env = Environment::current();
+  if (throwable) {
+    env->Throw(throwable.get());
+  }
+  if (env->ExceptionCheck() != JNI_TRUE) {
+    std::abort();
+  }
+}
+
+}
+
+// Functions that throw C++ exceptions
+
+// TODO(T6618159) Take a stack dump here to save context if it results in a crash when propagated
+void throwPendingJniExceptionAsCppException() {
+  JNIEnv* env = Environment::current();
+  if (env->ExceptionCheck() == JNI_FALSE) {
+    return;
+  }
+
+  auto throwable = adopt_local(env->ExceptionOccurred());
+  if (!throwable) {
+    throw std::runtime_error("Unable to get pending JNI exception.");
+  }
+  env->ExceptionClear();
+
+  throw JniException(throwable);
+}
+
+void throwCppExceptionIf(bool condition) {
+  if (!condition) {
+    return;
+  }
+
+  auto env = Environment::current();
+  if (env->ExceptionCheck() == JNI_TRUE) {
+    throwPendingJniExceptionAsCppException();
+    return;
+  }
+
+  throw JniException();
+}
+
+void throwNewJavaException(jthrowable throwable) {
+  throw JniException(wrap_alias(throwable));
+}
+
+void throwNewJavaException(const char* throwableName, const char* msg) {
+  // If anything of the fbjni calls fail, an exception of a suitable
+  // form will be thrown, which is what we want.
+  auto throwableClass = findClassLocal(throwableName);
+  auto throwable = throwableClass->newObject(
+    throwableClass->getConstructor<jthrowable(jstring)>(),
+    make_jstring(msg).release());
+  throwNewJavaException(throwable.get());
+}
+
+// Translate C++ to Java Exception
+
+namespace {
+
+// The implementation std::rethrow_if_nested uses a dynamic_cast to determine
+// if the exception is a nested_exception. If the exception is from a library
+// built with -fno-rtti, then that will crash. This avoids that.
+void rethrow_if_nested() {
+  try {
+    throw;
+  } catch (const std::nested_exception& e) {
+    e.rethrow_nested();
+  } catch (...) {
+  }
+}
+
+// For each exception in the chain of the currently handled exception, func
+// will be called with that exception as the currently handled exception (in
+// reverse order, i.e. innermost first).
+void denest(std::function<void()> func) {
+  try {
+    throw;
+  } catch (const std::exception& e) {
+    try {
+      rethrow_if_nested();
+    } catch (...) {
+      denest(func);
+    }
+    func();
+  } catch (...) {
+    func();
+  }
+}
+}
+
+void translatePendingCppExceptionToJavaException() noexcept {
+  local_ref<JThrowable> previous;
+  auto func = [&previous] () {
+    local_ref<JThrowable> current;
+    try {
+      throw;
+    } catch(const JniException& ex) {
+      current = ex.getThrowable();
+    } catch(const std::ios_base::failure& ex) {
+      current = JIOException::create(ex.what());
+    } catch(const std::bad_alloc& ex) {
+      current = JOutOfMemoryError::create(ex.what());
+    } catch(const std::out_of_range& ex) {
+      current = JArrayIndexOutOfBoundsException::create(ex.what());
+    } catch(const std::system_error& ex) {
+      current = JCppSystemErrorException::create(ex);
+    } catch(const std::runtime_error& ex) {
+      current = JRuntimeException::create(ex.what());
+    } catch(const std::exception& ex) {
+      current = JCppException::create(ex.what());
+    } catch(const char* msg) {
+      current = JUnknownCppException::create(msg);
+    } catch(...) {
+      current = JUnknownCppException::create();
+    }
+    if (previous) {
+      current->initCause(previous);
+    }
+    previous = current;
+  };
+
+  try {
+    denest(func);
+    setJavaExceptionAndAbortOnFailure(previous);
+  } catch (std::exception& e) {
+    FBLOGE("unexpected exception in translatePendingCppExceptionToJavaException: %s", e.what());
+    // std::terminate will print the message of the pending exception e
+    std::terminate();
+  } catch (...) {
+    FBLOGE("unexpected exception in translatePendingCppExceptionToJavaException");
+    std::terminate();
+  }
+}
+
+// JniException ////////////////////////////////////////////////////////////////////////////////////
+
+const std::string JniException::kExceptionMessageFailure_ = "Unable to get exception message.";
+
+JniException::JniException() : JniException(JRuntimeException::create()) { }
+
+JniException::JniException(alias_ref<jthrowable> throwable) : isMessageExtracted_(false) {
+  throwable_ = make_global(throwable);
+}
+
+JniException::JniException(JniException &&rhs)
+    : throwable_(std::move(rhs.throwable_)),
+      what_(std::move(rhs.what_)),
+      isMessageExtracted_(rhs.isMessageExtracted_) {
+}
+
+JniException::JniException(const JniException &rhs)
+    : what_(rhs.what_), isMessageExtracted_(rhs.isMessageExtracted_) {
+  throwable_ = make_global(rhs.throwable_);
+}
+
+JniException::~JniException() {
+  ThreadScope ts;
+  throwable_.reset();
+}
+
+local_ref<JThrowable> JniException::getThrowable() const noexcept {
+  return make_local(throwable_);
+}
+
+// TODO 6900503: consider making this thread-safe.
+void JniException::populateWhat() const noexcept {
+  ThreadScope ts;
+  try {
+    what_ = throwable_->toString();
+    isMessageExtracted_ = true;
+  } catch(...) {
+    what_ = kExceptionMessageFailure_;
+  }
+}
+
+const char* JniException::what() const noexcept {
+  if (!isMessageExtracted_) {
+    populateWhat();
+  }
+  return what_.c_str();
+}
+
+void JniException::setJavaException() const noexcept {
+  setJavaExceptionAndAbortOnFailure(throwable_);
+}
+
+}}
--- a/lib/fb/src/main/cpp/jni/Hybrid.cpp
+++ b/lib/fb/src/main/cpp/jni/Hybrid.cpp
@@ -0,0 +1,62 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include "fb/fbjni.h"
+
+
+namespace facebook {
+namespace jni {
+
+namespace detail {
+
+void HybridData::setNativePointer(std::unique_ptr<BaseHybridClass> new_value) {
+  static auto pointerField = getClass()->getField<jlong>("mNativePointer");
+  auto* old_value = reinterpret_cast<BaseHybridClass*>(getFieldValue(pointerField));
+  if (new_value) {
+    // Modify should only ever be called once with a non-null
+    // new_value.  If this happens again it's a programmer error, so
+    // blow up.
+    FBASSERTMSGF(old_value == 0, "Attempt to set C++ native pointer twice");
+  } else if (old_value == 0) {
+    return;
+  }
+  // delete on a null pointer is defined to be a noop.
+  delete old_value;
+  // This releases ownership from the unique_ptr, and passes the pointer, and
+  // ownership of it, to HybridData which is managed by the java GC.  The
+  // finalizer on hybridData calls resetNative which will delete the object, if
+  // resetNative has not already been called.
+  setFieldValue(pointerField, reinterpret_cast<jlong>(new_value.release()));
+}
+
+BaseHybridClass* HybridData::getNativePointer() {
+  static auto pointerField = getClass()->getField<jlong>("mNativePointer");
+  auto* value = reinterpret_cast<BaseHybridClass*>(getFieldValue(pointerField));
+  if (!value) {
+    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
+  }
+  return value;
+}
+
+local_ref<HybridData> HybridData::create() {
+  return newInstance();
+}
+
+}
+
+namespace {
+void resetNative(alias_ref<detail::HybridData> jthis) {
+  jthis->setNativePointer(nullptr);
+}
+}
+
+void HybridDataOnLoad() {
+  registerNatives("com/facebook/jni/HybridData", {
+      makeNativeMethod("resetNative", resetNative),
+  });
+}
+
+}}
--- a/lib/fb/src/main/cpp/jni/LocalString.cpp
+++ b/lib/fb/src/main/cpp/jni/LocalString.cpp
@@ -4,9 +4,11 @@
 * This source code is licensed under the MIT license found in the LICENSE
 * file in the root directory of this source tree.
 */
-#include <fbjni/detail/utf8.h>
+#include <jni/LocalString.h>
+#include <fb/Environment.h>
+#include <fb/assert.h>

-#include <fbjni/detail/Log.h>
+#include <vector>

 namespace facebook {
 namespace jni {
@@ -20,9 +22,7 @@ const uint16_t kUtf16HighSubHighBoundary  = 0xDC00;
 const uint16_t kUtf16LowSubHighBoundary   = 0xE000;

 inline void encode3ByteUTF8(char32_t code, uint8_t* out) {
-  if ((code & 0xffff0000) != 0) {
-    FBJNI_LOGF("3 byte utf-8 encodings only valid for up to 16 bits");
-  }
+  FBASSERTMSGF((code & 0xffff0000) == 0, "3 byte utf-8 encodings only valid for up to 16 bits");

  out[0] = 0xE0 | (code >> 12);
  out[1] = 0x80 | ((code >> 6) & 0x3F);
@@ -36,9 +36,7 @@ inline char32_t decode3ByteUTF8(const uint8_t* in) {
 }

 inline void encode4ByteUTF8(char32_t code, std::string& out, size_t offset) {
-  if ((code & 0xfff80000) != 0) {
-    FBJNI_LOGF("4 byte utf-8 encodings only valid for up to 21 bits");
-  }
+  FBASSERTMSGF((code & 0xfff80000) == 0, "4 byte utf-8 encodings only valid for up to 21 bits");

  out[offset] =     (char) (0xF0 | (code >> 18));
  out[offset + 1] = (char) (0x80 | ((code >> 12) & 0x3F));
@@ -102,13 +100,9 @@ void utf8ToModifiedUTF8(const uint8_t* utf8, size_t len, uint8_t* modified, size
 {
  size_t j = 0;
  for (size_t i = 0; i < len; ) {
-    if (j >= modifiedBufLen) {
-      FBJNI_LOGF("output buffer is too short");
-    }
+    FBASSERTMSGF(j < modifiedBufLen, "output buffer is too short");
    if (utf8[i] == 0) {
-      if (j + 1 >= modifiedBufLen) {
-        FBJNI_LOGF("output buffer is too short");
-      }
+      FBASSERTMSGF(j + 1 < modifiedBufLen, "output buffer is too short");
      modified[j] = 0xc0;
      modified[j + 1] = 0x80;
      i += 1;
@@ -148,18 +142,14 @@ void utf8ToModifiedUTF8(const uint8_t* utf8, size_t len, uint8_t* modified, size
    }

    // encode each as a 3 byte surrogate value
-    if (j + 5 >= modifiedBufLen) {
-      FBJNI_LOGF("output buffer is too short");
-    }
+    FBASSERTMSGF(j + 5 < modifiedBufLen, "output buffer is too short");
    encode3ByteUTF8(first, modified + j);
    encode3ByteUTF8(second, modified + j + 3);
    i += 4;
    j += 6;
  }

-  if (j >= modifiedBufLen) {
-    FBJNI_LOGF("output buffer is too short");
-  }
+  FBASSERTMSGF(j < modifiedBufLen, "output buffer is too short");
  modified[j++] = '\0';
 }

@@ -274,5 +264,46 @@ std::string utf16toUTF8(const uint16_t* utf16String, size_t utf16StringLen) noex
 }

 }
+
+LocalString::LocalString(const std::string& str)
+{
+  size_t modlen = detail::modifiedLength(str);
+  if (modlen == str.size()) {
+    // no supplementary characters, build jstring from input buffer
+    m_string = Environment::current()->NewStringUTF(str.data());
+    return;
+  }
+  auto modified = std::vector<char>(modlen + 1); // allocate extra byte for \0
+  detail::utf8ToModifiedUTF8(
+    reinterpret_cast<const uint8_t*>(str.data()), str.size(),
+    reinterpret_cast<uint8_t*>(modified.data()), modified.size());
+  m_string = Environment::current()->NewStringUTF(modified.data());
 }
+
+LocalString::LocalString(const char* str)
+{
+  size_t len;
+  size_t modlen = detail::modifiedLength(reinterpret_cast<const uint8_t*>(str), &len);
+  if (modlen == len) {
+    // no supplementary characters, build jstring from input buffer
+    m_string = Environment::current()->NewStringUTF(str);
+    return;
+  }
+  auto modified = std::vector<char>(modlen + 1); // allocate extra byte for \0
+  detail::utf8ToModifiedUTF8(
+    reinterpret_cast<const uint8_t*>(str), len,
+    reinterpret_cast<uint8_t*>(modified.data()), modified.size());
+  m_string = Environment::current()->NewStringUTF(modified.data());
 }
+
+LocalString::~LocalString() {
+  Environment::current()->DeleteLocalRef(m_string);
+}
+
+std::string fromJString(JNIEnv* env, jstring str) {
+  auto utf16String = JStringUtf16Extractor(env, str);
+  auto length = env->GetStringLength(str);
+  return detail::utf16toUTF8(utf16String, length);
+}
+
+} }
--- a/Show More
+++ b/Show More