move property storage into sub-object

Summary:
Here we introduce an abstraction over node property storage, in order to experiment with different approaches for Java/C integration.

- interface `YogaNodeProperties` as abstraction
- current JNI code factored into `YogaNodePropertiesJNI.java`
- `YogaNode` delegates all calls, no API changes

Reviewed By: astreet

Differential Revision: D8769448

fbshipit-source-id: e67327ce41fa047a51a986c652b3d59992a510e2

java/jni/YGJNI.cpp

@@ -21,6 +21,11 @@ struct JYogaConfig : public JavaClass<JYogaConfig> {
   static constexpr auto kJavaDescriptor = "Lcom/facebook/yoga/YogaConfig;";
 };
 
+struct JYogaNodePropertiesJNI : public JavaClass<JYogaNodePropertiesJNI> {
+  static constexpr auto kJavaDescriptor =
+      "Lcom/facebook/yoga/YogaNodePropertiesJNI;";
+};
+
 struct YGConfigContext {
   global_ref<jobject>* logger;
   global_ref<jobject>* config;
@@ -33,16 +38,34 @@ struct YGConfigContext {
   }
 };
 
+struct JNINodeContext {
+  weak_ref<JYogaNode> node;
+  weak_ref<JYogaNodePropertiesJNI> props;
+};
+
 static inline weak_ref<JYogaNode>* YGNodeJobject(YGNodeRef node) {
-  return reinterpret_cast<weak_ref<JYogaNode>*>(node->getContext());
+  return &reinterpret_cast<JNINodeContext*>(node->getContext())->node;
+}
+
+static inline weak_ref<JYogaNodePropertiesJNI>* YGNodePropsJObject(
+    YGNodeRef node) {
+  return &reinterpret_cast<JNINodeContext*>(node->getContext())->props;
+}
+
+static inline void setNodeContext(
+    YGNodeRef node,
+    alias_ref<JYogaNode> javaNode,
+    alias_ref<JYogaNodePropertiesJNI> javaNodeProps) {
+  node->setContext(
+      new JNINodeContext{make_weak(javaNode), make_weak(javaNodeProps)});
 }
 
 static void YGTransferLayoutDirection(
     YGNodeRef node,
-    alias_ref<jobject> javaNode) {
+    alias_ref<JYogaNodePropertiesJNI> javaProps) {
   static auto layoutDirectionField =
-      javaNode->getClass()->getField<jint>("mLayoutDirection");
-  javaNode->setFieldValue(
+      javaProps->getClass()->getField<jint>("mLayoutDirection");
+  javaProps->setFieldValue(
       layoutDirectionField, static_cast<jint>(YGNodeLayoutGetDirection(node)));
 }
 
@@ -50,7 +73,7 @@ static void YGTransferLayoutOutputsRecursive(YGNodeRef root) {
   if (!root->getHasNewLayout()) {
     return;
   }
-  auto obj = YGNodeJobject(root)->lockLocal();
+  auto obj = YGNodePropsJObject(root)->lockLocal();
   if (!obj) {
     YGLog(
         root,
@@ -223,7 +246,9 @@ static YGSize YGJNIMeasureFunc(
         findClassStatic("com/facebook/yoga/YogaNode")
             ->getMethod<jlong(jfloat, jint, jfloat, jint)>("measure");
 
-    YGTransferLayoutDirection(node, obj);
+    if (auto jProps = YGNodePropsJObject(node)->lockLocal()) {
+      YGTransferLayoutDirection(node, jProps);
+    }
     const auto measureResult =
         measureFunc(obj, width, widthMode, height, heightMode);
 
@@ -287,18 +312,21 @@ static int YGJNILogFunc(
   return result;
 }
 
-jlong jni_YGNodeNew(alias_ref<jobject> thiz) {
+jlong jni_YGNodeNew(
+    alias_ref<JYogaNodePropertiesJNI> javaProps,
+    alias_ref<JYogaNode> javaNode) {
   const YGNodeRef node = YGNodeNew();
-  node->setContext(new weak_ref<jobject>(make_weak(thiz)));
-  // YGNodeSetContext(node, new weak_ref<jobject>(make_weak(thiz)));
+  setNodeContext(node, javaNode, javaProps);
   node->setPrintFunc(YGPrint);
-  // YGNodeSetPrintFunc(node, YGPrint);
   return reinterpret_cast<jlong>(node);
 }
 
-jlong jni_YGNodeNewWithConfig(alias_ref<jobject> thiz, jlong configPointer) {
+jlong jni_YGNodeNewWithConfig(
+    alias_ref<JYogaNodePropertiesJNI> javaProps,
+    alias_ref<JYogaNode> javaNode,
+    jlong configPointer) {
   const YGNodeRef node = YGNodeNewWithConfig(_jlong2YGConfigRef(configPointer));
-  node->setContext(new weak_ref<jobject>(make_weak(thiz)));
+  setNodeContext(node, javaNode, javaProps);
   node->setPrintFunc(YGPrint);
   return reinterpret_cast<jlong>(node);
 }
@@ -314,18 +342,18 @@ void jni_YGNodeSetOwner(
 }
 
 jlong jni_YGNodeClone(
-    alias_ref<jobject> thiz,
+    alias_ref<jclass>,
     jlong nativePointer,
-    alias_ref<jobject> clonedJavaObject) {
+    alias_ref<JYogaNode> clonedJavaObject,
+    alias_ref<JYogaNodePropertiesJNI> clonedJavaProps) {
   const YGNodeRef clonedYogaNode = YGNodeClone(_jlong2YGNodeRef(nativePointer));
-  clonedYogaNode->setContext(
-      new weak_ref<jobject>(make_weak(clonedJavaObject)));
+  setNodeContext(clonedYogaNode, clonedJavaObject, clonedJavaProps);
   return reinterpret_cast<jlong>(clonedYogaNode);
 }
 
 void jni_YGNodeFree(alias_ref<jobject> thiz, jlong nativePointer) {
   const YGNodeRef node = _jlong2YGNodeRef(nativePointer);
-  delete YGNodeJobject(node);
+  delete reinterpret_cast<JNINodeContext*>(node->getContext());
   YGNodeFree(node);
 }
 
@@ -387,6 +415,12 @@ void jni_YGNodeCalculateLayout(
       static_cast<float>(width),
       static_cast<float>(height),
       YGNodeStyleGetDirection(_jlong2YGNodeRef(nativePointer)));
+}
+
+static void jni_YGTransferLayoutOutputsRecursive(
+    alias_ref<jclass>,
+    jlong nativePointer) {
+  const YGNodeRef root = _jlong2YGNodeRef(nativePointer);
   YGTransferLayoutOutputsRecursive(root);
 }
 
@@ -666,23 +700,14 @@ jint jni_YGNodeGetInstanceCount(alias_ref<jclass> clazz) {
 jint JNI_OnLoad(JavaVM* vm, void*) {
   return initialize(vm, [] {
     registerNatives(
-        "com/facebook/yoga/YogaNode",
+        "com/facebook/yoga/YogaNodePropertiesJNI",
         {
+            YGMakeNativeMethod(jni_YGNodeClone),
             YGMakeNativeMethod(jni_YGNodeNew),
             YGMakeNativeMethod(jni_YGNodeNewWithConfig),
             YGMakeNativeMethod(jni_YGNodeFree),
             YGMakeNativeMethod(jni_YGNodeReset),
-            YGMakeNativeMethod(jni_YGNodeClearChildren),
-            YGMakeNativeMethod(jni_YGNodeInsertChild),
-            YGMakeNativeMethod(jni_YGNodeInsertSharedChild),
-            YGMakeNativeMethod(jni_YGNodeRemoveChild),
-            YGMakeNativeMethod(jni_YGNodeCalculateLayout),
-            YGMakeNativeMethod(jni_YGNodeMarkDirty),
-            YGMakeNativeMethod(jni_YGNodeMarkDirtyAndPropogateToDescendants),
             YGMakeNativeMethod(jni_YGNodeIsDirty),
-            YGMakeNativeMethod(jni_YGNodeSetHasMeasureFunc),
-            YGMakeNativeMethod(jni_YGNodeSetHasBaselineFunc),
-            YGMakeNativeMethod(jni_YGNodeCopyStyle),
             YGMakeNativeMethod(jni_YGNodeStyleGetDirection),
             YGMakeNativeMethod(jni_YGNodeStyleSetDirection),
             YGMakeNativeMethod(jni_YGNodeStyleGetFlexDirection),
@@ -745,9 +770,23 @@ jint JNI_OnLoad(JavaVM* vm, void*) {
             YGMakeNativeMethod(jni_YGNodeStyleSetMaxHeightPercent),
             YGMakeNativeMethod(jni_YGNodeStyleGetAspectRatio),
             YGMakeNativeMethod(jni_YGNodeStyleSetAspectRatio),
+            YGMakeNativeMethod(jni_YGTransferLayoutOutputsRecursive),
+        });
+    registerNatives(
+        "com/facebook/yoga/YogaNode",
+        {
+            YGMakeNativeMethod(jni_YGNodeClearChildren),
+            YGMakeNativeMethod(jni_YGNodeInsertChild),
+            YGMakeNativeMethod(jni_YGNodeInsertSharedChild),
+            YGMakeNativeMethod(jni_YGNodeRemoveChild),
+            YGMakeNativeMethod(jni_YGNodeCalculateLayout),
+            YGMakeNativeMethod(jni_YGNodeMarkDirty),
+            YGMakeNativeMethod(jni_YGNodeMarkDirtyAndPropogateToDescendants),
+            YGMakeNativeMethod(jni_YGNodeSetHasMeasureFunc),
+            YGMakeNativeMethod(jni_YGNodeSetHasBaselineFunc),
+            YGMakeNativeMethod(jni_YGNodeCopyStyle),
             YGMakeNativeMethod(jni_YGNodeGetInstanceCount),
             YGMakeNativeMethod(jni_YGNodePrint),
-            YGMakeNativeMethod(jni_YGNodeClone),
             YGMakeNativeMethod(jni_YGNodeSetOwner),
         });
     registerNatives(