From a3f8e98b75d1eb7d2c4483b099bfc9193c82032a Mon Sep 17 00:00:00 2001
From: Patrick Wang <kk1fff@patrickz.net>
Date: Fri, 9 Nov 2012 22:09:24 -0800
Subject: [PATCH] Bug 806625 - Check if TabParent is destroyed before sending
 IPC message. r=cjones

---
 dom/ipc/TabParent.cpp | 73 ++++++++++++++++++++++++++++++++++++-------
 dom/ipc/TabParent.h   |  3 ++
 2 files changed, 65 insertions(+), 11 deletions(-)

diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index 475fce2ba91..4285e1f212a 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -86,6 +86,7 @@ TabParent::TabParent(const TabContext& aContext)
   , mDimensions(0, 0)
   , mDPI(0)
   , mShown(false)
+  , mIsDestroyed(false)
 {
 }
 
@@ -103,6 +104,10 @@ TabParent::SetOwnerElement(nsIDOMElement* aElement)
 void
 TabParent::Destroy()
 {
+  if (mIsDestroyed) {
+    return;
+  }
+
   // If this fails, it's most likely due to a content-process crash,
   // and auto-cleanup will kick in.  Otherwise, the child side will
   // destroy itself and send back __delete__().
@@ -117,6 +122,7 @@ TabParent::Destroy()
   if (RenderFrameParent* frame = GetRenderFrame()) {
     frame->Destroy();
   }
+  mIsDestroyed = true;
 }
 
 bool
@@ -214,6 +220,9 @@ TabParent::AnswerCreateWindow(PBrowserParent** retval)
 void
 TabParent::LoadURL(nsIURI* aURI)
 {
+    if (mIsDestroyed) {
+      return;
+    }
     if (!mShown) {
       nsAutoCString spec;
       if (aURI) {
@@ -236,12 +245,17 @@ TabParent::Show(const nsIntSize& size)
     // sigh
     mShown = true;
     mDimensions = size;
-    unused << SendShow(size);
+    if (!mIsDestroyed) {
+      unused << SendShow(size);
+    }
 }
 
 void
 TabParent::UpdateDimensions(const nsRect& rect, const nsIntSize& size)
 {
+  if (mIsDestroyed) {
+    return;
+  }
   unused << SendUpdateDimensions(rect, size);
   if (RenderFrameParent* rfp = GetRenderFrame()) {
     rfp->NotifyDimensionsChanged(size.width, size.height);
@@ -252,34 +266,46 @@ TabParent::UpdateDimensions(const nsRect& rect, const nsIntSize& size)
 void
 TabParent::UpdateFrame(const FrameMetrics& aFrameMetrics)
 {
-  unused << SendUpdateFrame(aFrameMetrics);
+  if (!mIsDestroyed) {
+    unused << SendUpdateFrame(aFrameMetrics);
+  }
 }
 
 void TabParent::HandleDoubleTap(const nsIntPoint& aPoint)
 {
-  unused << SendHandleDoubleTap(aPoint);
+  if (!mIsDestroyed) {
+    unused << SendHandleDoubleTap(aPoint);
+  }
 }
 
 void TabParent::HandleSingleTap(const nsIntPoint& aPoint)
 {
-  unused << SendHandleSingleTap(aPoint);
+  if (!mIsDestroyed) {
+    unused << SendHandleSingleTap(aPoint);
+  }
 }
 
 void TabParent::HandleLongTap(const nsIntPoint& aPoint)
 {
-  unused << SendHandleLongTap(aPoint);
+  if (!mIsDestroyed) {
+    unused << SendHandleLongTap(aPoint);
+  }
 }
 
 void
 TabParent::Activate()
 {
+  if (!mIsDestroyed) {
     unused << SendActivate();
+  }
 }
 
 void
 TabParent::Deactivate()
 {
-  unused << SendDeactivate();
+  if (!mIsDestroyed) {
+    unused << SendDeactivate();
+  }
 }
 
 NS_IMETHODIMP
@@ -340,9 +366,11 @@ TabParent::SendMouseEvent(const nsAString& aType, float aX, float aY,
                           int32_t aButton, int32_t aClickCount,
                           int32_t aModifiers, bool aIgnoreRootScrollFrame)
 {
-  unused << PBrowserParent::SendMouseEvent(nsString(aType), aX, aY,
-                                           aButton, aClickCount,
-                                           aModifiers, aIgnoreRootScrollFrame);
+  if (!mIsDestroyed) {
+    unused << PBrowserParent::SendMouseEvent(nsString(aType), aX, aY,
+                                             aButton, aClickCount,
+                                             aModifiers, aIgnoreRootScrollFrame);
+  }
 }
 
 void
@@ -352,12 +380,17 @@ TabParent::SendKeyEvent(const nsAString& aType,
                         int32_t aModifiers,
                         bool aPreventDefault)
 {
-  unused << PBrowserParent::SendKeyEvent(nsString(aType), aKeyCode, aCharCode,
-                                         aModifiers, aPreventDefault);
+  if (!mIsDestroyed) {
+    unused << PBrowserParent::SendKeyEvent(nsString(aType), aKeyCode, aCharCode,
+                                           aModifiers, aPreventDefault);
+  }
 }
 
 bool TabParent::SendRealMouseEvent(nsMouseEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   nsMouseEvent e(event);
   MaybeForwardEventToRenderFrame(event, &e);
   return PBrowserParent::SendRealMouseEvent(e);
@@ -365,6 +398,9 @@ bool TabParent::SendRealMouseEvent(nsMouseEvent& event)
 
 bool TabParent::SendMouseWheelEvent(WheelEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   WheelEvent e(event);
   MaybeForwardEventToRenderFrame(event, &e);
   return PBrowserParent::SendMouseWheelEvent(event);
@@ -372,6 +408,9 @@ bool TabParent::SendMouseWheelEvent(WheelEvent& event)
 
 bool TabParent::SendRealKeyEvent(nsKeyEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   nsKeyEvent e(event);
   MaybeForwardEventToRenderFrame(event, &e);
   return PBrowserParent::SendRealKeyEvent(e);
@@ -379,6 +418,9 @@ bool TabParent::SendRealKeyEvent(nsKeyEvent& event)
 
 bool TabParent::SendRealTouchEvent(nsTouchEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   if (event.message == NS_TOUCH_START) {
     MOZ_ASSERT((!sEventCapturer && mEventCaptureDepth == 0) ||
                (sEventCapturer == this && mEventCaptureDepth > 0));
@@ -647,6 +689,9 @@ TabParent::HandleQueryContentEvent(nsQueryContentEvent& aEvent)
 bool
 TabParent::SendCompositionEvent(nsCompositionEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   mIMEComposing = event.message != NS_COMPOSITION_END;
   mIMECompositionStart = NS_MIN(mIMESelectionAnchor, mIMESelectionFocus);
   if (mIMECompositionEnding)
@@ -665,6 +710,9 @@ TabParent::SendCompositionEvent(nsCompositionEvent& event)
 bool
 TabParent::SendTextEvent(nsTextEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   if (mIMECompositionEnding) {
     mIMECompositionText = event.theText;
     return true;
@@ -685,6 +733,9 @@ TabParent::SendTextEvent(nsTextEvent& event)
 bool
 TabParent::SendSelectionEvent(nsSelectionEvent& event)
 {
+  if (mIsDestroyed) {
+    return false;
+  }
   mIMESelectionAnchor = event.mOffset + (event.mReversed ? event.mLength : 0);
   mIMESelectionFocus = event.mOffset + (!event.mReversed ? event.mLength : 0);
   event.seqno = ++mIMESeqno;
diff --git a/dom/ipc/TabParent.h b/dom/ipc/TabParent.h
index eef891e11f3..7f54e277ed2 100644
--- a/dom/ipc/TabParent.h
+++ b/dom/ipc/TabParent.h
@@ -296,6 +296,9 @@ private:
     // dispatch to content.
     void MaybeForwardEventToRenderFrame(const nsInputEvent& aEvent,
                                         nsInputEvent* aOutEvent);
+    // When true, the TabParent is invalid and we should not send IPC messages
+    // anymore.
+    bool mIsDestroyed;
 };
 
 } // namespace dom