Bug 927033 - Don't reset mApzcForInputBlock until all touches are gone [r=kats]

gfx/layers/composite/APZCTreeManager.cpp

@@ -16,6 +16,7 @@
 #include "mozilla/MouseEvents.h"
 #include "mozilla/mozalloc.h"           // for operator new
 #include "mozilla/TouchEvents.h"
+#include "nsDebug.h"                    // for NS_WARNING
 #include "nsPoint.h"                    // for nsIntPoint
 #include "nsTArray.h"                   // for nsTArray, nsTArray_Impl, etc
 #include "nsThreadUtils.h"              // for NS_IsMainThread
@@ -29,7 +30,8 @@ namespace layers {
 float APZCTreeManager::sDPI = 72.0;
 
 APZCTreeManager::APZCTreeManager()
-    : mTreeLock("APZCTreeLock")
+    : mTreeLock("APZCTreeLock"),
+      mTouchCount(0)
 {
   MOZ_ASSERT(NS_IsMainThread());
   AsyncPanZoomController::InitializeGlobalState();
@@ -238,6 +240,7 @@ APZCTreeManager::ReceiveInputEvent(const InputData& aEvent)
     case MULTITOUCH_INPUT: {
       const MultiTouchInput& multiTouchInput = aEvent.AsMultiTouchInput();
       if (multiTouchInput.mType == MultiTouchInput::MULTITOUCH_START) {
+        mTouchCount++;
         mApzcForInputBlock = GetTargetAPZC(ScreenPoint(multiTouchInput.mTouches[0].mScreenPoint));
         for (size_t i = 1; i < multiTouchInput.mTouches.Length(); i++) {
           nsRefPtr<AsyncPanZoomController> apzc2 = GetTargetAPZC(ScreenPoint(multiTouchInput.mTouches[i].mScreenPoint));
@@ -267,10 +270,18 @@ APZCTreeManager::ReceiveInputEvent(const InputData& aEvent)
           ApplyTransform(&(inputForApzc.mTouches[i].mScreenPoint), transformToApzc);
         }
         result = mApzcForInputBlock->ReceiveInputEvent(inputForApzc);
+      }
+      if (multiTouchInput.mType == MultiTouchInput::MULTITOUCH_CANCEL ||
+          multiTouchInput.mType == MultiTouchInput::MULTITOUCH_END) {
+        if (mTouchCount >= multiTouchInput.mTouches.Length()) {
+          mTouchCount -= multiTouchInput.mTouches.Length();
+        } else {
+          NS_WARNING("Got an unexpected touchend/touchcancel");
+          mTouchCount = 0;
+        }
         // If we have an mApzcForInputBlock and it's the end of the touch sequence
         // then null it out so we don't keep a dangling reference and leak things.
-        if (multiTouchInput.mType == MultiTouchInput::MULTITOUCH_CANCEL ||
-            (multiTouchInput.mType == MultiTouchInput::MULTITOUCH_END && multiTouchInput.mTouches.Length() == 1)) {
+        if (mTouchCount == 0) {
           mApzcForInputBlock = nullptr;
         }
       }
@@ -356,9 +367,17 @@ APZCTreeManager::ProcessTouchEvent(const WidgetTouchEvent& aEvent,
   // If we have an mApzcForInputBlock and it's the end of the touch sequence
   // then null it out so we don't keep a dangling reference and leak things.
   if (aEvent.message == NS_TOUCH_CANCEL ||
-      (aEvent.message == NS_TOUCH_END && aEvent.touches.Length() == 1)) {
+      aEvent.message == NS_TOUCH_END) {
+    if (mTouchCount >= aEvent.touches.Length()) {
+      mTouchCount -= aEvent.touches.Length();
+    } else {
+      NS_WARNING("Got an unexpected touchend/touchcancel");
+      mTouchCount = 0;
+    }
+    if (mTouchCount == 0) {
       mApzcForInputBlock = nullptr;
     }
+  }
   return ret;
 }
 
@@ -410,6 +429,7 @@ APZCTreeManager::ReceiveInputEvent(const WidgetInputEvent& aEvent,
         return nsEventStatus_eIgnore;
       }
       if (touchEvent.message == NS_TOUCH_START) {
+        mTouchCount++;
         ScreenPoint point = ScreenPoint(touchEvent.touches[0]->mRefPoint.x, touchEvent.touches[0]->mRefPoint.y);
         mApzcForInputBlock = GetTouchInputBlockAPZC(touchEvent, point);
       }
@@ -442,6 +462,7 @@ APZCTreeManager::ReceiveInputEvent(WidgetInputEvent& aEvent)
         return nsEventStatus_eIgnore;
       }
       if (touchEvent.message == NS_TOUCH_START) {
+        mTouchCount++;
         ScreenPoint point = ScreenPoint(touchEvent.touches[0]->mRefPoint.x, touchEvent.touches[0]->mRefPoint.y);
         mApzcForInputBlock = GetTouchInputBlockAPZC(touchEvent, point);
       }

gfx/layers/composite/APZCTreeManager.h

@@ -321,6 +321,8 @@ private:
    * input delivery thread, and so does not require locking.
    */
   nsRefPtr<AsyncPanZoomController> mApzcForInputBlock;
+  /* The number of touch points we are tracking that are currently on the screen. */
+  uint32_t mTouchCount;
   /* The transform from root screen coordinates into mApzcForInputBlock's
    * screen coordinates, as returned through the 'aTransformToApzcOut' parameter
    * of GetInputTransform(), at the start of the input block. This is cached

gfx/layers/ipc/GestureEventListener.cpp

@@ -1,5 +1,5 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set sw=4 ts=8 et tw=80 : */
+/* vim: set sw=2 ts=8 et tw=80 : */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
@@ -73,11 +73,7 @@ nsEventStatus GestureEventListener::HandleInputEvent(const InputData& aEvent)
         }
       }
 
-      NS_WARN_IF_FALSE(!foundAlreadyExistingTouch, "Tried to add a touch that already exists");
-
       // If we didn't find a touch in our list that matches this, then add it.
-      // If it already existed, we don't want to add it twice because that
-      // messes with our touch move/end code.
       if (!foundAlreadyExistingTouch) {
         mTouches.AppendElement(event.mTouches[i]);
       }
@@ -137,17 +133,16 @@ nsEventStatus GestureEventListener::HandleInputEvent(const InputData& aEvent)
   }
   case MultiTouchInput::MULTITOUCH_END:
   case MultiTouchInput::MULTITOUCH_LEAVE: {
+    for (size_t i = 0; i < event.mTouches.Length(); i++) {
       bool foundAlreadyExistingTouch = false;
-    for (size_t i = 0; i < event.mTouches.Length() && !foundAlreadyExistingTouch; i++) {
       for (size_t j = 0; j < mTouches.Length() && !foundAlreadyExistingTouch; j++) {
         if (event.mTouches[i].mIdentifier == mTouches[j].mIdentifier) {
           foundAlreadyExistingTouch = true;
           mTouches.RemoveElementAt(j);
         }
       }
-    }
-
       NS_WARN_IF_FALSE(foundAlreadyExistingTouch, "Touch ended, but not in list");
+    }
 
     if (mState == GESTURE_WAITING_DOUBLE_TAP) {
       CancelDoubleTapTimeoutTask();

gfx/layers/ipc/GestureEventListener.h

@@ -1,5 +1,5 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set sw=4 ts=8 et tw=80 : */
+/* vim: set sw=2 ts=8 et tw=80 : */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */