From e20e784d95cc8c9d6ffd1dc15b14e8fe602ce684 Mon Sep 17 00:00:00 2001
From: Jim Mathies <jmathies@mozilla.com>
Date: Fri, 13 Sep 2013 05:34:24 -0500
Subject: [PATCH] Bug 914331 - On pointer released make sure all gecko touch
 events are delivered to insure dom state via accessibility is up to date.
 r=tabraldes, bbondy

---
 widget/windows/winrt/MetroAppShell.cpp | 64 ++++++++++++++++++++++++--
 widget/windows/winrt/MetroAppShell.h   |  2 +
 widget/windows/winrt/MetroInput.cpp    | 17 +++----
 widget/windows/winrt/MetroInput.h      |  1 -
 4 files changed, 69 insertions(+), 15 deletions(-)

diff --git a/widget/windows/winrt/MetroAppShell.cpp b/widget/windows/winrt/MetroAppShell.cpp
index 58bece2e127..37f521a24da 100644
--- a/widget/windows/winrt/MetroAppShell.cpp
+++ b/widget/windows/winrt/MetroAppShell.cpp
@@ -42,6 +42,8 @@ extern UINT sAppShellGeckoMsgId;
 
 static ComPtr<ICoreWindowStatic> sCoreStatic;
 static bool sIsDispatching = false;
+static bool sWillEmptyThreadQueue = false;
+static bool sEmptyingThreadQueue = false;
 
 MetroAppShell::~MetroAppShell()
 {
@@ -214,6 +216,43 @@ MetroAppShell::Run(void)
   return rv;
 }
 
+// Called in certain cases where we have async input events in the thread
+// queue and need to make sure they get dispatched before the stack unwinds.
+void // static
+MetroAppShell::MarkEventQueueForPurge()
+{
+  LogFunction();
+  sWillEmptyThreadQueue = true;
+
+  // If we're dispatching native events, wait until the dispatcher is
+  // off the stack.
+  if (sIsDispatching) {
+    return;
+  }
+
+  // Safe to process pending events now
+  DispatchAllGeckoEvents();
+}
+
+// static
+void
+MetroAppShell::DispatchAllGeckoEvents()
+{
+  if (!sWillEmptyThreadQueue) {
+    return;
+  }
+
+  LogFunction();
+  NS_ASSERTION(NS_IsMainThread(), "DispatchAllXPCOMEvents should be called on the main thread");
+
+  sWillEmptyThreadQueue = false;
+
+  AutoRestore<bool> dispatching(sEmptyingThreadQueue);
+  sEmptyingThreadQueue = true;
+  nsIThread *thread = NS_GetCurrentThread();
+  NS_ProcessPendingEvents(thread, 0);
+}
+
 static void
 ProcessNativeEvents(CoreProcessEventsOption eventOption)
 {
@@ -238,16 +277,35 @@ bool
 MetroAppShell::ProcessOneNativeEventIfPresent()
 {
   if (sIsDispatching) {
-    NS_RUNTIMEABORT("Reentrant call into process events, this is not allowed in Winrt land. Goodbye!");
+    // Calling into ProcessNativeEvents is harmless, but won't actually process any
+    // native events. So we log here so we can spot this and get a handle on the
+    // corner cases where this can happen.
+    Log("WARNING: Reentrant call into process events detected, returning early.");
+    return false;
   }
-  AutoRestore<bool> dispatching(sIsDispatching);
-  ProcessNativeEvents(CoreProcessEventsOption::CoreProcessEventsOption_ProcessOneIfPresent);
+
+  {
+    AutoRestore<bool> dispatching(sIsDispatching);
+    sIsDispatching = true;
+    ProcessNativeEvents(CoreProcessEventsOption::CoreProcessEventsOption_ProcessOneIfPresent);
+  }
+
+  DispatchAllGeckoEvents();
+
   return !!HIWORD(::GetQueueStatus(MOZ_QS_ALLEVENT));
 }
 
 bool
 MetroAppShell::ProcessNextNativeEvent(bool mayWait)
 {
+  // NS_ProcessPendingEvents will process thread events *and* call
+  // nsBaseAppShell::OnProcessNextEvent to process native events. However
+  // we do not want native events getting dispatched while we are in
+  // DispatchAllGeckoEvents.
+  if (sEmptyingThreadQueue) {
+    return false;
+  }
+
   if (ProcessOneNativeEventIfPresent()) {
     return true;
   }
diff --git a/widget/windows/winrt/MetroAppShell.h b/widget/windows/winrt/MetroAppShell.h
index 93d5468ead3..59c9b87cf30 100644
--- a/widget/windows/winrt/MetroAppShell.h
+++ b/widget/windows/winrt/MetroAppShell.h
@@ -27,12 +27,14 @@ public:
 
   static LRESULT CALLBACK EventWindowProc(HWND, UINT, WPARAM, LPARAM);
   static bool ProcessOneNativeEventIfPresent();
+  static void MarkEventQueueForPurge();
 
 protected:
   NS_IMETHOD Run();
 
   virtual void ScheduleNativeEventCallback();
   virtual bool ProcessNextNativeEvent(bool mayWait);
+  static void DispatchAllGeckoEvents();
   virtual ~MetroAppShell();
 
   HWND mEventWnd;
diff --git a/widget/windows/winrt/MetroInput.cpp b/widget/windows/winrt/MetroInput.cpp
index 763e1f3e0ba..8ef8cd2fa26 100644
--- a/widget/windows/winrt/MetroInput.cpp
+++ b/widget/windows/winrt/MetroInput.cpp
@@ -12,6 +12,7 @@
 #include "nsIDOMSimpleGestureEvent.h" // Constants for gesture events
 #include "InputData.h"
 #include "UIABridgePrivate.h"
+#include "MetroAppShell.h"
 
 // System headers (alphabetical)
 #include <windows.ui.core.h> // ABI::Window::UI::Core namespace
@@ -635,6 +636,11 @@ MetroInput::OnPointerReleased(UI::Core::ICoreWindow* aSender,
     mGestureRecognizer->ProcessUpEvent(currentPoint.Get());
   }
 
+  // Make sure all gecko events are dispatched and the dom is up to date
+  // so that when ui automation comes in looking for focus info it gets
+  // the right information.
+  MetroAppShell::MarkEventQueueForPurge();
+
   return S_OK;
 }
 
@@ -1091,17 +1097,6 @@ MetroInput::DeliverNextQueuedEventIgnoreStatus()
   delete event;
 }
 
-nsEventStatus
-MetroInput::DeliverNextQueuedEvent()
-{
-  nsGUIEvent* event = static_cast<nsGUIEvent*>(mInputEventQueue.PopFront());
-  MOZ_ASSERT(event);
-  nsEventStatus status;
-  mWidget->DispatchEvent(event, status);
-  delete event;
-  return status;
-}
-
 void
 MetroInput::DispatchAsyncTouchEventIgnoreStatus(nsTouchEvent* aEvent)
 {
diff --git a/widget/windows/winrt/MetroInput.h b/widget/windows/winrt/MetroInput.h
index da14c29740d..4d9eb3d4ae7 100644
--- a/widget/windows/winrt/MetroInput.h
+++ b/widget/windows/winrt/MetroInput.h
@@ -264,7 +264,6 @@ private:
 
   // Async event callbacks
   void DeliverNextQueuedEventIgnoreStatus();
-  nsEventStatus DeliverNextQueuedEvent();
   nsEventStatus DeliverNextQueuedTouchEvent();
 
   // Misc. specialty async callbacks