Make DOMWrapperWorld::current() callable from workers

Source/bindings/v8/DOMWrapperWorld.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef DOMWrapperWorld_h
 #define DOMWrapperWorld_h
 
 #include "bindings/v8/V8PerContextData.h"
 #include "platform/weborigin/SecurityOrigin.h"
+#include "wtf/MainThread.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 #include <v8.h>
 
 namespace WebCore {
 
 class DOMDataStore;
 class ScriptController;
@@ skipping 15 matching lines @@
 
     static const int mainWorldExtensionGroup = 0;
     static PassRefPtr<DOMWrapperWorld> ensureIsolatedWorld(int worldId, int extensionGroup);
     ~DOMWrapperWorld();
 
     static bool isolatedWorldsExist() { return isolatedWorldCount; }
     static void allWorldsInMainThread(Vector<RefPtr<DOMWrapperWorld> >& worlds);
 
     static DOMWrapperWorld* world(v8::Handle<v8::Context> context)
     {
-        ASSERT(contextHasCorrectPrototype(context));

[haraken, 2014/03/04 04:19:45]

I removed this ASSERT for the following reasons:

- Now DOMWrapperWorld::world() is called from anywhere (worker worlds, testing
worlds etc). So if we really want to have the ASSERT, we need to write:

#ifdef NDEBUG
  if (world->isMainWorld() || world->isIsolatedWorld())
    ASSERT(contextHasCorrectPrototype(context));
#endif

- Instead of having such complicated ASSERT, we already have a better ASSERT in
V8PerContextData. Specifically, V8PerContextData already has an ASSERT to check
that the context has a non-0 world inside the embedder data of the context. I
think this ASSERT is enough to verify that we're calling
DOMWrapperWorld::world() for a valid context.

What do you think?

         return V8PerContextData::world(context);
     }
 
-    // Will return null if there is no DOMWrapperWorld for the current v8::Context
-    static DOMWrapperWorld* current(v8::Isolate*);
+    // Will return null if there is no DOMWrapperWorld for the current context.
+    static DOMWrapperWorld* current(v8::Isolate* isolate)
+    {
+        v8::Handle<v8::Context> context = isolate->GetCurrentContext();
+        if (context.IsEmpty()) {
+            // If a worker thread calls current() with an empty context, it means that there is no DOMWrapperWorld.
+            if (!isMainThread())
+                return 0;
+
+            // If the main thread calls current() with an empty context, it's possible that
+            // current() is being called while window is being initialized.
+            // In order to make current() workable during the initialization phase,
+            // we cache the world of the initializing window on worldOfInitializingWindow.
+            // If there is no initiazing window, worldOfInitializingWindow is 0.
+            return worldOfInitializingWindow;
+        }
+        return world(context);
+    }
+
     static DOMWrapperWorld* mainWorld();
 
     // Associates an isolated world (see above for description) with a security
     // origin. XMLHttpRequest instances used in that world will be considered
     // to come from that origin, not the frame's.
     static void setIsolatedWorldSecurityOrigin(int worldID, PassRefPtr<SecurityOrigin>);
     static void clearIsolatedWorldSecurityOrigin(int worldID);
     SecurityOrigin* isolatedWorldSecurityOrigin();
 
     // Associated an isolated world with a Content Security Policy. Resources
     // embedded into the main world's DOM from script executed in an isolated
     // world should be restricted based on the isolated world's DOM, not the
     // main world's.
     //
     // FIXME: Right now, resource injection simply bypasses the main world's
     // DOM. More work is necessary to allow the isolated world's policy to be
     // applied correctly.
     static void setIsolatedWorldContentSecurityPolicy(int worldID, const String& policy);
     static void clearIsolatedWorldContentSecurityPolicy(int worldID);
     bool isolatedWorldHasContentSecurityPolicy();
 
     bool isMainWorld() const { return m_worldId == MainWorldId; }
     bool isWorkerWorld() const { return m_worldId == WorkerWorldId; }
     bool isIsolatedWorld() const { return MainWorldId < m_worldId  && m_worldId <= EmbedderWorldIdLimit; }
 
     int worldId() const { return m_worldId; }
     int extensionGroup() const { return m_extensionGroup; }
     DOMDataStore& domDataStore() { return *m_domDataStore; }
 
+    static void setWorldOfInitializingWindow(DOMWrapperWorld* world)
+    {
+        ASSERT(isMainThread());
+        worldOfInitializingWindow = world;
+    }
+    // FIXME: Remove this method once we fix crbug.com/345014.
+    static bool windowIsBeingInitialized() { return !!worldOfInitializingWindow; }
+
 private:
+    DOMWrapperWorld(int worldId, int extensionGroup);
+
     static unsigned isolatedWorldCount;
-
-    DOMWrapperWorld(int worldId, int extensionGroup);
-    static bool contextHasCorrectPrototype(v8::Handle<v8::Context>);
+    static DOMWrapperWorld* worldOfInitializingWindow;
 
     const int m_worldId;
     const int m_extensionGroup;
     OwnPtr<DOMDataStore> m_domDataStore;
 };
 
 } // namespace WebCore
 
 #endif // DOMWrapperWorld_h