From 5c86b5d9cd4543e6d04f8ef7fb1ba8f1c881c7ff Mon Sep 17 00:00:00 2001
From: Sunny Goyal <sunnygoyal@google.com>
Date: Thu, 22 Feb 2018 11:14:18 -0800
Subject: [PATCH] Synchronizing invalidating interaction handler with the
 eventQueue.

In some cases, eventQueue could be running on the background thread where as
the invalidate happens on the UI thread, which could cause race conditions in
touch consumer

Change-Id: Iebd84238eb2b5d6774beaa3bc21afdeb09e62561
---
 .../quickstep/BaseSwipeInteractionHandler.java    |  6 ++----
 .../quickstep/NavBarSwipeInteractionHandler.java  |  2 +-
 .../quickstep/OtherActivityTouchConsumer.java     | 15 ++++++---------
 .../quickstep/WindowTransformSwipeHandler.java    |  2 +-
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/quickstep/src/com/android/quickstep/BaseSwipeInteractionHandler.java b/quickstep/src/com/android/quickstep/BaseSwipeInteractionHandler.java
index 5bf7e4ec90..b3ebd772cc 100644
--- a/quickstep/src/com/android/quickstep/BaseSwipeInteractionHandler.java
+++ b/quickstep/src/com/android/quickstep/BaseSwipeInteractionHandler.java
@@ -20,13 +20,11 @@ import android.support.annotation.WorkerThread;
 import com.android.launcher3.states.InternalStateHandler;
 import com.android.quickstep.TouchConsumer.InteractionType;
 
-import java.util.function.Consumer;
-
 public abstract class BaseSwipeInteractionHandler extends InternalStateHandler {
 
-    protected Consumer<BaseSwipeInteractionHandler> mGestureEndCallback;
+    protected Runnable mGestureEndCallback;
 
-    public void setGestureEndCallback(Consumer<BaseSwipeInteractionHandler> gestureEndCallback) {
+    public void setGestureEndCallback(Runnable gestureEndCallback) {
         mGestureEndCallback = gestureEndCallback;
     }
 
diff --git a/quickstep/src/com/android/quickstep/NavBarSwipeInteractionHandler.java b/quickstep/src/com/android/quickstep/NavBarSwipeInteractionHandler.java
index ae70474c0d..ff7d434e7f 100644
--- a/quickstep/src/com/android/quickstep/NavBarSwipeInteractionHandler.java
+++ b/quickstep/src/com/android/quickstep/NavBarSwipeInteractionHandler.java
@@ -347,7 +347,7 @@ public class NavBarSwipeInteractionHandler extends BaseSwipeInteractionHandler i
     public void reset() {
         mCurrentShift.cancelAnimation();
         if (mGestureEndCallback != null) {
-            mGestureEndCallback.accept(this);
+            mGestureEndCallback.run();
         }
     }
 
diff --git a/quickstep/src/com/android/quickstep/OtherActivityTouchConsumer.java b/quickstep/src/com/android/quickstep/OtherActivityTouchConsumer.java
index 604b60b90d..786ade38bd 100644
--- a/quickstep/src/com/android/quickstep/OtherActivityTouchConsumer.java
+++ b/quickstep/src/com/android/quickstep/OtherActivityTouchConsumer.java
@@ -230,6 +230,9 @@ public class OtherActivityTouchConsumer extends ContextWrapper implements TouchC
     }
 
     private void notifyGestureStarted() {
+        if (mInteractionHandler == null) {
+            return;
+        }
         // Notify the handler that the gesture has actually started
         mInteractionHandler.onGestureStarted();
 
@@ -275,7 +278,7 @@ public class OtherActivityTouchConsumer extends ContextWrapper implements TouchC
         // Preload the plan
         mRecentsModel.loadTasks(mRunningTask.id, null);
         mInteractionHandler = handler;
-        mInteractionHandler.setGestureEndCallback(this::onFinish);
+        mInteractionHandler.setGestureEndCallback(mEventQueue::reset);
     }
 
     private Bitmap getCurrentTaskSnapshot() {
@@ -314,7 +317,7 @@ public class OtherActivityTouchConsumer extends ContextWrapper implements TouchC
         // Preload the plan
         mRecentsModel.loadTasks(mRunningTask.id, null);
         mInteractionHandler = handler;
-        handler.setGestureEndCallback(this::onFinish);
+        handler.setGestureEndCallback(mEventQueue::reset);
 
         CountDownLatch drawWaitLock = new CountDownLatch(1);
         handler.setLauncherOnDrawCallback(() -> {
@@ -408,8 +411,8 @@ public class OtherActivityTouchConsumer extends ContextWrapper implements TouchC
         // Clean up the old interaction handler
         if (mInteractionHandler != null) {
             final BaseSwipeInteractionHandler handler = mInteractionHandler;
-            mMainThreadExecutor.execute(handler::reset);
             mInteractionHandler = null;
+            mMainThreadExecutor.execute(handler::reset);
         }
     }
 
@@ -450,12 +453,6 @@ public class OtherActivityTouchConsumer extends ContextWrapper implements TouchC
         }
     }
 
-    private void onFinish(BaseSwipeInteractionHandler handler) {
-        if (mInteractionHandler == handler) {
-            mInteractionHandler = null;
-        }
-    }
-
     public void switchToMainChoreographer() {
         mEventQueue.setInterimChoreographer(null);
     }
diff --git a/quickstep/src/com/android/quickstep/WindowTransformSwipeHandler.java b/quickstep/src/com/android/quickstep/WindowTransformSwipeHandler.java
index ac253c70d9..a6192c2f50 100644
--- a/quickstep/src/com/android/quickstep/WindowTransformSwipeHandler.java
+++ b/quickstep/src/com/android/quickstep/WindowTransformSwipeHandler.java
@@ -688,7 +688,7 @@ public class WindowTransformSwipeHandler extends BaseSwipeInteractionHandler {
         mCurrentShift.cancelAnimation();
 
         if (mGestureEndCallback != null) {
-            mGestureEndCallback.accept(this);
+            mGestureEndCallback.run();
         }
 
         clearReference();