Set layout outputs on java object from C

Summary: Set layout outputs on CSSNode from C after layout calculation finishes instead of relying on calling jni gettings from java code. This should be much more efficient as it avoids a lot of jni overhead and also allows for calling getLayoutWidth() etc multiple times without incurring a penalty.

Reviewed By: lexs

Differential Revision: D4077968

fbshipit-source-id: bce86ba610cd5ae36cfb45d78b2609c63a14cfa3

java/com/facebook/csslayout/CSSNode.java

@@ -45,6 +45,17 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
   private boolean mHasSetBorder = false;
   private boolean mHasSetPosition = false;
 
+  @DoNotStrip
+  private float mWidth = CSSConstants.UNDEFINED;
+  @DoNotStrip
+  private float mHeight = CSSConstants.UNDEFINED;
+  @DoNotStrip
+  private float mTop = CSSConstants.UNDEFINED;
+  @DoNotStrip
+  private float mLeft = CSSConstants.UNDEFINED;
+  @DoNotStrip
+  private int mLayoutDirection = 0;
+
   private native long jni_CSSNodeNew();
   public CSSNode() {
     mNativePointer = jni_CSSNodeNew();
@@ -73,6 +84,12 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
     mHasSetBorder = false;
     mHasSetPosition = false;
 
+    mWidth = CSSConstants.UNDEFINED;
+    mHeight = CSSConstants.UNDEFINED;
+    mTop = CSSConstants.UNDEFINED;
+    mLeft = CSSConstants.UNDEFINED;
+    mLayoutDirection = 0;
+
     mMeasureFunction = null;
     mData = null;
 
@@ -176,12 +193,6 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
     jni_CSSNodeStyleSetDirection(mNativePointer, direction.ordinal());
   }
 
-  private native int jni_CSSNodeLayoutGetDirection(long nativePointer);
-  @Override
-  public CSSDirection getLayoutDirection() {
-    return CSSDirection.values()[jni_CSSNodeLayoutGetDirection(mNativePointer)];
-  }
-
   private native int jni_CSSNodeStyleGetFlexDirection(long nativePointer);
   @Override
   public CSSFlexDirection getFlexDirection() {
@@ -450,28 +461,29 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
     jni_CSSNodeStyleSetMaxHeight(mNativePointer, maxheight);
   }
 
-  private native float jni_CSSNodeLayoutGetLeft(long nativePointer);
   @Override
   public float getLayoutX() {
-    return jni_CSSNodeLayoutGetLeft(mNativePointer);
+    return mLeft;
   }
 
-  private native float jni_CSSNodeLayoutGetTop(long nativePointer);
   @Override
   public float getLayoutY() {
-    return jni_CSSNodeLayoutGetTop(mNativePointer);
+    return mTop;
   }
 
-  private native float jni_CSSNodeLayoutGetWidth(long nativePointer);
   @Override
   public float getLayoutWidth() {
-    return jni_CSSNodeLayoutGetWidth(mNativePointer);
+    return mWidth;
   }
 
-  private native float jni_CSSNodeLayoutGetHeight(long nativePointer);
   @Override
   public float getLayoutHeight() {
-    return jni_CSSNodeLayoutGetHeight(mNativePointer);
+    return mHeight;
+  }
+
+  @Override
+  public CSSDirection getLayoutDirection() {
+    return CSSDirection.values()[mLayoutDirection];
   }
 
   private native void jni_CSSNodeSetHasMeasureFunc(long nativePointer, boolean hasMeasureFunc);

java/jni/CSSJNI.cpp

@@ -14,6 +14,31 @@
 using namespace facebook::jni;
 using namespace std;
 
+static void _jniTransferLayoutDirection(CSSNodeRef node, alias_ref<jobject> javaNode) {
+  static auto layoutDirectionField = javaNode->getClass()->getField<jint>("mLayoutDirection");
+  javaNode->setFieldValue(layoutDirectionField, static_cast<jint>(CSSNodeLayoutGetDirection(node)));
+}
+
+static void _jniTransferLayoutOutputsRecursive(CSSNodeRef root) {
+  auto javaNode = adopt_local(
+      Environment::current()->NewLocalRef(reinterpret_cast<jweak>(CSSNodeGetContext(root))));
+
+  static auto widthField = javaNode->getClass()->getField<jfloat>("mWidth");
+  static auto heightField = javaNode->getClass()->getField<jfloat>("mHeight");
+  static auto leftField = javaNode->getClass()->getField<jfloat>("mLeft");
+  static auto topField = javaNode->getClass()->getField<jfloat>("mTop");
+
+  javaNode->setFieldValue(widthField, CSSNodeLayoutGetWidth(root));
+  javaNode->setFieldValue(heightField, CSSNodeLayoutGetHeight(root));
+  javaNode->setFieldValue(leftField, CSSNodeLayoutGetLeft(root));
+  javaNode->setFieldValue(topField, CSSNodeLayoutGetTop(root));
+  _jniTransferLayoutDirection(root, javaNode);
+
+  for (uint32_t i = 0; i < CSSNodeChildCount(root); i++) {
+    _jniTransferLayoutOutputsRecursive(CSSNodeGetChild(root, i));
+  }
+}
+
 static void _jniPrint(CSSNodeRef node) {
   auto obj = adopt_local(Environment::current()->NewLocalRef(reinterpret_cast<jweak>(CSSNodeGetContext(node))));
   cout << obj->toString() << endl;
@@ -25,8 +50,11 @@ static CSSSize _jniMeasureFunc(CSSNodeRef node,
                                float height,
                                CSSMeasureMode heightMode) {
   auto obj = adopt_local(Environment::current()->NewLocalRef(reinterpret_cast<jweak>(CSSNodeGetContext(node))));
+
   static auto measureFunc =
       obj->getClass()->getMethod<jlong(jfloat, jint, jfloat, jint)>("measure");
+
+  _jniTransferLayoutDirection(node, obj);
   const auto measureResult = measureFunc(obj, width, widthMode, height, heightMode);
 
   static_assert(sizeof(measureResult) == 8,
@@ -79,10 +107,12 @@ void jni_CSSNodeRemoveChild(alias_ref<jobject>, jlong nativePointer, jlong child
 }
 
 void jni_CSSNodeCalculateLayout(alias_ref<jobject>, jlong nativePointer) {
-  CSSNodeCalculateLayout(_jlong2CSSNodeRef(nativePointer),
+  const CSSNodeRef root = _jlong2CSSNodeRef(nativePointer);
+  CSSNodeCalculateLayout(root,
                          CSSUndefined,
                          CSSUndefined,
                          CSSNodeStyleGetDirection(_jlong2CSSNodeRef(nativePointer)));
+  _jniTransferLayoutOutputsRecursive(root);
 }
 
 void jni_CSSNodeMarkDirty(alias_ref<jobject>, jlong nativePointer) {
@@ -139,11 +169,6 @@ void jni_CSSNodeMarkLayoutSeen(alias_ref<jobject>, jlong nativePointer) {
                           static_cast<type>(value));                                       \
   }
 
-#define CSS_NODE_JNI_LAYOUT_PROP(javatype, type, name)                           \
-  javatype jni_CSSNodeLayoutGet##name(alias_ref<jobject>, jlong nativePointer) { \
-    return (javatype) CSSNodeLayoutGet##name(_jlong2CSSNodeRef(nativePointer));  \
-  }
-
 CSS_NODE_JNI_STYLE_PROP(jint, CSSDirection, Direction);
 CSS_NODE_JNI_STYLE_PROP(jint, CSSFlexDirection, FlexDirection);
 CSS_NODE_JNI_STYLE_PROP(jint, CSSJustify, JustifyContent);
@@ -173,12 +198,6 @@ CSS_NODE_JNI_STYLE_PROP(jfloat, float, Height);
 CSS_NODE_JNI_STYLE_PROP(jfloat, float, MinHeight);
 CSS_NODE_JNI_STYLE_PROP(jfloat, float, MaxHeight);
 
-CSS_NODE_JNI_LAYOUT_PROP(jfloat, float, Width);
-CSS_NODE_JNI_LAYOUT_PROP(jfloat, float, Height);
-CSS_NODE_JNI_LAYOUT_PROP(jfloat, float, Left);
-CSS_NODE_JNI_LAYOUT_PROP(jfloat, float, Top);
-CSS_NODE_JNI_LAYOUT_PROP(jint, CSSDirection, Direction);
-
 #define CSSMakeNativeMethod(name) makeNativeMethod(#name, name)
 
 jint JNI_OnLoad(JavaVM *vm, void *) {
@@ -244,12 +263,6 @@ jint JNI_OnLoad(JavaVM *vm, void *) {
                         CSSMakeNativeMethod(jni_CSSNodeStyleGetMaxHeight),
                         CSSMakeNativeMethod(jni_CSSNodeStyleSetMaxHeight),
 
-                        CSSMakeNativeMethod(jni_CSSNodeLayoutGetLeft),
-                        CSSMakeNativeMethod(jni_CSSNodeLayoutGetTop),
-                        CSSMakeNativeMethod(jni_CSSNodeLayoutGetWidth),
-                        CSSMakeNativeMethod(jni_CSSNodeLayoutGetHeight),
-                        CSSMakeNativeMethod(jni_CSSNodeLayoutGetDirection),
-
                         CSSMakeNativeMethod(jni_CSSNodeGetInstanceCount),
                     });
   });