From 46e67ef42892270ad3dcf792192009e048246f2a Mon Sep 17 00:00:00 2001
From: Krzysztof Magiera <krzysztof@fb.com>
Date: Wed, 28 Oct 2015 02:11:09 -0700
Subject: [PATCH] Recycle touch events.

Reviewed By: andreicoman11

Differential Revision: D2590149

fb-gh-sync-id: 97c60e12385526097431a192b692e2f92813722d
---
 .../com/facebook/react/ReactRootView.java     | 12 +++---
 .../react/uimanager/events/TouchEvent.java    | 42 ++++++++++++++-----
 2 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
index f7aeb89b4..5e21647df 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
@@ -145,7 +145,7 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
       mChildIsHandlingNativeGesture = false;
       mTargetTag = TouchTargetHelper.findTargetTagForTouch(ev.getY(), ev.getX(), this);
       eventDispatcher.dispatchEvent(
-          new TouchEvent(mTargetTag, SystemClock.uptimeMillis(),TouchEventType.START, ev));
+          TouchEvent.obtain(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.START, ev));
     } else if (mChildIsHandlingNativeGesture) {
       // If the touch was intercepted by a child, we've already sent a cancel event to JS for this
       // gesture, so we shouldn't send any more touches related to it.
@@ -161,20 +161,20 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
       // End of the gesture. We reset target tag to -1 and expect no further event associated with
       // this gesture.
       eventDispatcher.dispatchEvent(
-          new TouchEvent(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.END, ev));
+          TouchEvent.obtain(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.END, ev));
       mTargetTag = -1;
     } else if (action == MotionEvent.ACTION_MOVE) {
       // Update pointer position for current gesture
       eventDispatcher.dispatchEvent(
-          new TouchEvent(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.MOVE, ev));
+          TouchEvent.obtain(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.MOVE, ev));
     } else if (action == MotionEvent.ACTION_POINTER_DOWN) {
       // New pointer goes down, this can only happen after ACTION_DOWN is sent for the first pointer
       eventDispatcher.dispatchEvent(
-          new TouchEvent(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.START, ev));
+          TouchEvent.obtain(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.START, ev));
     } else if (action == MotionEvent.ACTION_POINTER_UP) {
       // Exactly onw of the pointers goes up
       eventDispatcher.dispatchEvent(
-          new TouchEvent(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.END, ev));
+          TouchEvent.obtain(mTargetTag, SystemClock.uptimeMillis(), TouchEventType.END, ev));
     } else if (action == MotionEvent.ACTION_CANCEL) {
       dispatchCancelEvent(ev);
       mTargetTag = -1;
@@ -219,7 +219,7 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
         !mChildIsHandlingNativeGesture,
         "Expected to not have already sent a cancel for this gesture");
     Assertions.assertNotNull(eventDispatcher).dispatchEvent(
-        new TouchEvent(
+        TouchEvent.obtain(
             mTargetTag,
             SystemClock.uptimeMillis(),
             TouchEventType.CANCEL,
diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchEvent.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchEvent.java
index 8bfe1f00a..10a4bda3a 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchEvent.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchEvent.java
@@ -9,6 +9,7 @@
 
 package com.facebook.react.uimanager.events;
 
+import android.support.v4.util.Pools;
 import android.view.MotionEvent;
 
 /**
@@ -21,16 +22,42 @@ import android.view.MotionEvent;
  */
 public class TouchEvent extends Event<TouchEvent> {
 
-  private final MotionEvent mMotionEvent;
-  private final TouchEventType mTouchEventType;
-  private final short mCoalescingKey;
+  private static final Pools.SynchronizedPool<TouchEvent> EVENTS_POOL =
+      new Pools.SynchronizedPool<>(3);
 
-  public TouchEvent(
+  public static TouchEvent obtain(
       int viewTag,
       long timestampMs,
       TouchEventType touchEventType,
       MotionEvent motionEventToCopy) {
-    super(viewTag, timestampMs);
+    TouchEvent event = EVENTS_POOL.acquire();
+    if (event == null) {
+      event = new TouchEvent();
+    }
+    event.init(viewTag, timestampMs, touchEventType, motionEventToCopy);
+    return event;
+  }
+
+  private MotionEvent mMotionEvent;
+  private TouchEventType mTouchEventType;
+  private short mCoalescingKey;
+
+  private TouchEvent() {
+  }
+
+  @Override
+  public void onDispose() {
+    mMotionEvent.recycle();
+    mMotionEvent = null;
+    EVENTS_POOL.release(this);
+  }
+
+  private void init(
+      int viewTag,
+      long timestampMs,
+      TouchEventType touchEventType,
+      MotionEvent motionEventToCopy) {
+    super.init(viewTag, timestampMs);
     mTouchEventType = touchEventType;
     mMotionEvent = MotionEvent.obtain(motionEventToCopy);
 
@@ -94,9 +121,4 @@ public class TouchEvent extends Event<TouchEvent> {
         getViewTag(),
         mMotionEvent);
   }
-
-  @Override
-  public void onDispose() {
-    mMotionEvent.recycle();
-  }
 }