added flag for useBatchingForLayoutOutputs experiment

Summary:
Using a config flag to switch between different implementations of transferring layout outputs
- YogaNodeJNI uses multiple access of java fields to pass all properties like width, height, margin etc...
- YogaNodeJNIBatching uses a float array to pass all the data in one java field access

Reviewed By: davidaurelio

Differential Revision: D14378301

fbshipit-source-id: 0da5b28e6a67ad8fd60eb7efe622d9b2deaf177f

lib/yoga/src/main/java/com/facebook/yoga/YogaConfig.java

@@ -11,6 +11,7 @@
 public class YogaConfig {
 
   public static int SPACING_TYPE = 1;
+  public static boolean useBatchingForLayoutOutputs = false;
 
   long mNativePointer;
   private YogaLogger mLogger;

lib/yoga/src/main/java/com/facebook/yoga/YogaNative.java

@@ -29,8 +29,8 @@ public class YogaNative {
 
   // YGNode related
   static native int jni_YGNodeGetInstanceCount();
-  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);

lib/yoga/src/main/java/com/facebook/yoga/YogaNode.java

@@ -10,11 +10,11 @@
 
 public abstract class YogaNode {
   public static YogaNode create() {
-    return new YogaNodeJNI();
+    return YogaConfig.useBatchingForLayoutOutputs ? new YogaNodeJNIBatching() : new YogaNodeJNI();
   }
 
   public static YogaNode create(YogaConfig config) {
-    return new YogaNodeJNI(config);
+    return YogaConfig.useBatchingForLayoutOutputs ? new YogaNodeJNIBatching(config) : new YogaNodeJNI(config);
   }
 
   public abstract void reset();

lib/yoga/src/main/java/com/facebook/yoga/YogaNodeJNIBase.java

@@ -22,14 +22,14 @@ public abstract class YogaNodeJNIBase extends YogaNode {
   @Nullable private Object mData;
 
   public YogaNodeJNIBase() {
-    mNativePointer = YogaNative.jni_YGNodeNew();
+    mNativePointer = YogaNative.jni_YGNodeNew(YogaConfig.useBatchingForLayoutOutputs);
     if (mNativePointer == 0) {
       throw new IllegalStateException("Failed to allocate native memory");
     }
   }
 
   public YogaNodeJNIBase(YogaConfig config) {
-    mNativePointer = YogaNative.jni_YGNodeNewWithConfig(config.mNativePointer);
+    mNativePointer = YogaNative.jni_YGNodeNewWithConfig(config.mNativePointer, YogaConfig.useBatchingForLayoutOutputs);
     if (mNativePointer == 0) {
       throw new IllegalStateException("Failed to allocate native memory");
     }

lib/yogajni/src/main/cpp/jni/YGJNI.cpp

@@ -72,6 +72,8 @@ 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;
+
 class PtrJNodeMap {
   using JNodeArray = JArrayClass<JYogaNode::javaobject>;
   std::map<YGNodeRef, size_t> ptrsToIdxs_;
@@ -194,7 +196,7 @@ static void YGTransferLayoutOutputsRecursive(
 
   auto edgesSet = YGNodeEdges{root};
 
-  if (false) {
+  if (useBatchingForLayoutOutputs) {
     bool marginFieldSet = edgesSet.has(YGNodeEdges::MARGIN);
     bool paddingFieldSet = edgesSet.has(YGNodeEdges::PADDING);
     bool borderFieldSet = edgesSet.has(YGNodeEdges::BORDER);
@@ -431,16 +433,21 @@ static int YGJNILogFunc(
   return result;
 }
 
-jlong jni_YGNodeNew(alias_ref<jclass>) {
+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);
 }