Add FpsListener to React Scroll Views

Summary:
We want to give people the ability to log scroll performance (including Fb).
This adds an interface that can be enabled and disabled from the react scroll views.
This is a prerequisite to implementing the actual framerate logger that will log dropped
frames while scrolling in prod.

Reviewed By: astreet

Differential Revision: D3283588

fbshipit-source-id: ed9736cb9ed3f441511647f36b1460092bd91e56

ReactAndroid/src/main/java/com/facebook/react/views/scroll/FpsListener.java

@@ -0,0 +1,35 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.react.views.scroll;
+
+public interface FpsListener {
+
+  /**
+   * Clients should call this method when they want the listener to begin recording data.
+   *
+   * @param tag
+   */
+  void enable(String tag);
+
+  /**
+   * Clients should call this method when they want the listener to stop recording data.
+   * The listener will then report the data it collected.
+   *
+   * Calling disable on a listener that has already been disabled is a no-op.
+   *
+   * @param tag
+   */
+  void disable(String tag);
+
+  /**
+   * Reports whether this listener is recording data.
+   */
+  boolean isEnabled();
+}

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollView.java

@@ -44,11 +44,22 @@ public class ReactHorizontalScrollView extends HorizontalScrollView implements
   private boolean mRemoveClippedSubviews;
   private boolean mScrollEnabled = true;
   private boolean mSendMomentumEvents;
+  private @Nullable FpsListener mFpsListener = null;
+  private @Nullable String mScrollPerfTag;
   private @Nullable Drawable mEndBackground;
   private int mEndFillColor = Color.TRANSPARENT;
 
   public ReactHorizontalScrollView(Context context) {
+    this(context, null);
+  }
+
+  public ReactHorizontalScrollView(Context context, @Nullable FpsListener fpsListener) {
     super(context);
+    mFpsListener = fpsListener;
+  }
+
+  public void setScrollPerfTag(@Nullable String scrollPerfTag) {
+    mScrollPerfTag = scrollPerfTag;
   }
 
   @Override
@@ -117,6 +128,7 @@ public class ReactHorizontalScrollView extends HorizontalScrollView implements
       NativeGestureUtil.notifyNativeGestureStarted(this, ev);
       ReactScrollViewHelper.emitScrollBeginDragEvent(this);
       mDragging = true;
+      enableFpsListener();
       return true;
     }
 
@@ -193,6 +205,26 @@ public class ReactHorizontalScrollView extends HorizontalScrollView implements
     }
   }
 
+  private void enableFpsListener() {
+    if (isScrollPerfLoggingEnabled()) {
+      Assertions.assertNotNull(mFpsListener);
+      Assertions.assertNotNull(mScrollPerfTag);
+      mFpsListener.enable(mScrollPerfTag);
+    }
+  }
+
+  private void disableFpsListener() {
+    if (isScrollPerfLoggingEnabled()) {
+      Assertions.assertNotNull(mFpsListener);
+      Assertions.assertNotNull(mScrollPerfTag);
+      mFpsListener.disable(mScrollPerfTag);
+    }
+  }
+
+  private boolean isScrollPerfLoggingEnabled() {
+    return mFpsListener != null && mScrollPerfTag != null && !mScrollPerfTag.isEmpty();
+  }
+
   @Override
   public void draw(Canvas canvas) {
     if (mEndFillColor != Color.TRANSPARENT) {
@@ -214,7 +246,7 @@ public class ReactHorizontalScrollView extends HorizontalScrollView implements
   @TargetApi(16)
   private void handlePostTouchScrolling() {
     // If we aren't going to do anything (send events or snap to page), we can early out.
-    if (!mSendMomentumEvents && !mPagingEnabled) {
+    if (!mSendMomentumEvents && !mPagingEnabled && !isScrollPerfLoggingEnabled()) {
       return;
     }
 
@@ -253,6 +285,7 @@ public class ReactHorizontalScrollView extends HorizontalScrollView implements
               ReactScrollViewHelper.emitScrollMomentumEndEvent(ReactHorizontalScrollView.this);
             }
             ReactHorizontalScrollView.this.mPostTouchRunnable = null;
+            disableFpsListener();
           } else {
             ReactHorizontalScrollView.this.postOnAnimationDelayed(this, ReactScrollViewHelper.MOMENTUM_DELAY);
           }

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java

@@ -30,6 +30,15 @@ public class ReactHorizontalScrollViewManager
     implements ReactScrollViewCommandHelper.ScrollCommandHandler<ReactHorizontalScrollView> {
 
   private static final String REACT_CLASS = "AndroidHorizontalScrollView";
+  private @Nullable FpsListener mFpsListener = null;
+
+  public ReactHorizontalScrollViewManager() {
+    this(null);
+  }
+
+  public ReactHorizontalScrollViewManager(@Nullable FpsListener fpsListener) {
+    mFpsListener = fpsListener;
+  }
 
   @Override
   public String getName() {
@@ -38,7 +47,7 @@ public class ReactHorizontalScrollViewManager
 
   @Override
   public ReactHorizontalScrollView createViewInstance(ThemedReactContext context) {
-    return new ReactHorizontalScrollView(context);
+    return new ReactHorizontalScrollView(context, mFpsListener);
   }
 
   @ReactProp(name = "scrollEnabled", defaultBoolean = true)
@@ -69,6 +78,18 @@ public class ReactHorizontalScrollViewManager
     view.setSendMomentumEvents(sendMomentumEvents);
   }
 
+  /**
+   * Tag used for logging scroll performance on this scroll view. Will force momentum events to be
+   * turned on (see setSendMomentumEvents).
+   *
+   * @param view
+   * @param scrollPerfTag
+   */
+  @ReactProp(name = "scrollPerfTag")
+  public void setScrollPerfTag(ReactHorizontalScrollView view, String scrollPerfTag) {
+    view.setScrollPerfTag(scrollPerfTag);
+  }
+
   @ReactProp(name = "pagingEnabled")
   public void setPagingEnabled(ReactHorizontalScrollView view, boolean pagingEnabled) {
     view.setPagingEnabled(pagingEnabled);

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollView.java

@@ -45,17 +45,28 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
   private boolean mRemoveClippedSubviews;
   private boolean mScrollEnabled = true;
   private boolean mSendMomentumEvents;
+  private @Nullable FpsListener mFpsListener = null;
+  private @Nullable String mScrollPerfTag;
   private @Nullable Drawable mEndBackground;
   private int mEndFillColor = Color.TRANSPARENT;
 
   public ReactScrollView(Context context) {
+    this(context, null);
+  }
+
+  public ReactScrollView(Context context, @Nullable FpsListener fpsListener) {
     super(context);
+    mFpsListener = fpsListener;
   }
 
   public void setSendMomentumEvents(boolean sendMomentumEvents) {
     mSendMomentumEvents = sendMomentumEvents;
   }
 
+  public void setScrollPerfTag(String scrollPerfTag) {
+    mScrollPerfTag = scrollPerfTag;
+  }
+
   public void setScrollEnabled(boolean scrollEnabled) {
     mScrollEnabled = scrollEnabled;
   }
@@ -118,6 +129,7 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
       NativeGestureUtil.notifyNativeGestureStarted(this, ev);
       ReactScrollViewHelper.emitScrollBeginDragEvent(this);
       mDragging = true;
+      enableFpsListener();
       return true;
     }
 
@@ -134,6 +146,7 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
     if (action == MotionEvent.ACTION_UP && mDragging) {
       ReactScrollViewHelper.emitScrollEndDragEvent(this);
       mDragging = false;
+      disableFpsListener();
     }
     return super.onTouchEvent(ev);
   }
@@ -175,14 +188,16 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
   @Override
   public void fling(int velocityY) {
     super.fling(velocityY);
-    if (mSendMomentumEvents) {
+    if (mSendMomentumEvents || isScrollPerfLoggingEnabled()) {
       mFlinging = true;
+      enableFpsListener();
       ReactScrollViewHelper.emitScrollMomentumBeginEvent(this);
       Runnable r = new Runnable() {
         @Override
         public void run() {
           if (mDoneFlinging) {
             mFlinging = false;
+            disableFpsListener();
             ReactScrollViewHelper.emitScrollMomentumEndEvent(ReactScrollView.this);
           } else {
             mDoneFlinging = true;
@@ -194,6 +209,26 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
     }
   }
 
+  private void enableFpsListener() {
+    if (isScrollPerfLoggingEnabled()) {
+      Assertions.assertNotNull(mFpsListener);
+      Assertions.assertNotNull(mScrollPerfTag);
+      mFpsListener.enable(mScrollPerfTag);
+    }
+  }
+
+  private void disableFpsListener() {
+    if (isScrollPerfLoggingEnabled()) {
+      Assertions.assertNotNull(mFpsListener);
+      Assertions.assertNotNull(mScrollPerfTag);
+      mFpsListener.disable(mScrollPerfTag);
+    }
+  }
+
+  private boolean isScrollPerfLoggingEnabled() {
+    return mFpsListener != null && mScrollPerfTag != null && !mScrollPerfTag.isEmpty();
+  }
+
   @Override
   public void draw(Canvas canvas) {
     if (mEndFillColor != Color.TRANSPARENT) {

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java

@@ -33,6 +33,15 @@ public class ReactScrollViewManager
     implements ReactScrollViewCommandHelper.ScrollCommandHandler<ReactScrollView> {
 
   private static final String REACT_CLASS = "RCTScrollView";
+  private @Nullable FpsListener mFpsListener = null;
+
+  public ReactScrollViewManager() {
+    this(null);
+  }
+
+  public ReactScrollViewManager(@Nullable FpsListener fpsListener) {
+    mFpsListener = fpsListener;
+  }
 
   @Override
   public String getName() {
@@ -41,7 +50,7 @@ public class ReactScrollViewManager
 
   @Override
   public ReactScrollView createViewInstance(ThemedReactContext context) {
-    return new ReactScrollView(context);
+    return new ReactScrollView(context, mFpsListener);
   }
 
   @ReactProp(name = "scrollEnabled", defaultBoolean = true)
@@ -72,6 +81,18 @@ public class ReactScrollViewManager
     view.setSendMomentumEvents(sendMomentumEvents);
   }
 
+  /**
+   * Tag used for logging scroll performance on this scroll view. Will force momentum events to be
+   * turned on (see setSendMomentumEvents).
+   *
+   * @param view
+   * @param scrollPerfTag
+   */
+  @ReactProp(name = "scrollPerfTag")
+  public void setScrollPerfTag(ReactScrollView view, String scrollPerfTag) {
+    view.setScrollPerfTag(scrollPerfTag);
+  }
+
   /**
    * When set, fills the rest of the scrollview with a color to avoid setting a background and
    * creating unnecessary overdraw.