Changeset 149208 in webkit

Timestamp:

Apr 26, 2013, 2:13:22 PM (12 years ago)

Author:

Simon Fraser

Message:

Inspector window is often blank when opened
​https://bugs.webkit.org/show_bug.cgi?id=115220
<rdar://problem/13735496>

Reviewed by Tim Horton.

After disabling tiled scrolling and accelerated drawing in r149006, the
Inspector window was often missing its content after opening. This only
happened when the user has a preference on disk to use accelerated drawing
in the Inspector.

The missing content was caused by a failure to connect the correct contextID
for remote layer hosting. On window creation, we hook up a context using
WindowServer layer hosting (the default), but then switch back to app-hosted
layers for the Inspector window. This switching happens in didUpdateBackingStoreState(),
but that can be re-entered via its call to sendUpdateBackingStoreState(). In
that cause, on unwinding the stack it would call enterAcceleratedCompositingMode()
with a stale layerTreeContext.

Fix by moving the code that exits/enters accelerated compositing mode to before
the call to sendUpdateBackingStoreState() that can cause re-entrancy. That avoids
use of a possibly stale layerTreeContext.

• UIProcess/DrawingAreaProxyImpl.cpp:

(WebKit::DrawingAreaProxyImpl::didUpdateBackingStoreState):

Location:

trunk/Source/WebKit2

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/DrawingAreaProxyImpl.cpp (modified) (2 diffs)

trunk/Source/WebKit2/ChangeLog

@@ +1 @@
+2013-04-26  Simon Fraser  <simon.fraser@apple.com>
+
+        Inspector window is often blank when opened
+        https://bugs.webkit.org/show_bug.cgi?id=115220
+
+        Reviewed by Tim Horton.
+        
+        After disabling tiled scrolling and accelerated drawing in r149006, the
+        Inspector window was often missing its content after opening. This only
+        happened when the user has a preference on disk to use accelerated drawing
+        in the Inspector.
+        
+        The missing content was caused by a failure to connect the correct contextID
+        for remote layer hosting. On window creation, we hook up a context using
+        WindowServer layer hosting (the default), but then switch back to app-hosted
+        layers for the Inspector window. This switching happens in didUpdateBackingStoreState(),
+        but that can be re-entered via its call to sendUpdateBackingStoreState(). In
+        that cause, on unwinding the stack it would call enterAcceleratedCompositingMode()
+        with a stale layerTreeContext.
+        
+        Fix by moving the code that exits/enters accelerated compositing mode to before
+        the call to sendUpdateBackingStoreState() that can cause re-entrancy. That avoids
+        use of a possibly stale layerTreeContext.
+
+        * UIProcess/DrawingAreaProxyImpl.cpp:
+        (WebKit::DrawingAreaProxyImpl::didUpdateBackingStoreState):
+
 2013-04-26  Alexey Proskuryakov  <ap@apple.com>
 

trunk/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp

@@ -194 +194 @@
     m_webPageProxy->process()->responsivenessTimer()->stop();
 
-    if (m_nextBackingStoreStateID != m_currentBackingStoreStateID)
-        sendUpdateBackingStoreState(RespondImmediately);
-    else
-        m_hasReceivedFirstUpdate = true;
-
 #if USE(ACCELERATED_COMPOSITING)
     if (layerTreeContext != m_layerTreeContext) {
@@ -211 +206 @@
         }            
     }
-
+#endif
+
+    if (m_nextBackingStoreStateID != m_currentBackingStoreStateID)
+        sendUpdateBackingStoreState(RespondImmediately);
+    else
+        m_hasReceivedFirstUpdate = true;
+
+#if USE(ACCELERATED_COMPOSITING)
     if (isInAcceleratedCompositingMode()) {
         ASSERT(!m_backingStore);