Changeset 144522 in webkit

Timestamp:

Mar 1, 2013 6:35:53 PM (11 years ago)

Author:

commit-queue@webkit.org

Message:

Don't leak Documents when using MutationObserver from extensions
​https://bugs.webkit.org/show_bug.cgi?id=111234

Patch by Elliott Sprehn <Elliott Sprehn> on 2013-03-01
Reviewed by Adam Barth.

.:

• ManualTests/leak-observer-nonmain-world.html: Added.

Source/WebCore:

MutationObserverCallback holds a WorldContextHandle which secretly isn't
a handle to anything when it's for the main world. When it's for a non-main
world though, like those used in extensions, it becomes a strong reference
to the v8::Context which results in leaks by creating cycles:

MutationObserver -> Callback -> World -> Document -> Node -> MutationObserver.

Instead we should keep a RefPtr to a DOMWrapperWorld in the callback and then
get the v8::Context from that inside handleEvent.

Tests: ManualTests/leak-observer-nonmain-world.html

• bindings/v8/V8Binding.cpp:

(WebCore::toV8Context): Added overload that takes a DOMWrapperWorld.

• bindings/v8/V8Binding.h:
• bindings/v8/V8MutationCallback.cpp:

(WebCore::V8MutationCallback::V8MutationCallback):
(WebCore::V8MutationCallback::handleEvent):

• bindings/v8/V8MutationCallback.h:

(V8MutationCallback):

Location:

trunk

Files:

• ChangeLog (modified) (1 diff)
• ManualTests/leak-observer-nonmain-world.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/bindings/v8/V8Binding.cpp (modified) (1 diff)
• Source/WebCore/bindings/v8/V8Binding.h (modified) (1 diff)
• Source/WebCore/bindings/v8/V8MutationCallback.cpp (modified) (2 diffs)
• Source/WebCore/bindings/v8/V8MutationCallback.h (modified) (2 diffs)

trunk/ChangeLog

@@ +1 @@
+2013-03-01  Elliott Sprehn  <esprehn@gmail.com>
+
+        Don't leak Documents when using MutationObserver from extensions
+        https://bugs.webkit.org/show_bug.cgi?id=111234
+
+        Reviewed by Adam Barth.
+
+        * ManualTests/leak-observer-nonmain-world.html: Added.
+
 2013-02-27  Zan Dobersek  <zdobersek@igalia.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-03-01  Elliott Sprehn  <esprehn@gmail.com>
+
+        Don't leak Documents when using MutationObserver from extensions
+        https://bugs.webkit.org/show_bug.cgi?id=111234
+
+        Reviewed by Adam Barth.
+
+        MutationObserverCallback holds a WorldContextHandle which secretly isn't
+        a handle to anything when it's for the main world. When it's for a non-main
+        world though, like those used in extensions, it becomes a strong reference
+        to the v8::Context which results in leaks by creating cycles:
+
+        MutationObserver -> Callback -> World -> Document -> Node -> MutationObserver.
+
+        Instead we should keep a RefPtr to a DOMWrapperWorld in the callback and then
+        get the v8::Context from that inside handleEvent.
+
+        Tests: ManualTests/leak-observer-nonmain-world.html
+
+        * bindings/v8/V8Binding.cpp:
+        (WebCore::toV8Context): Added overload that takes a DOMWrapperWorld.
+        * bindings/v8/V8Binding.h:
+        * bindings/v8/V8MutationCallback.cpp:
+        (WebCore::V8MutationCallback::V8MutationCallback):
+        (WebCore::V8MutationCallback::handleEvent):
+        * bindings/v8/V8MutationCallback.h:
+        (V8MutationCallback):
+
 2013-03-01  Bear Travis  <betravis@adobe.com>
 

trunk/Source/WebCore/bindings/v8/V8Binding.cpp

@@ -267 +267 @@
 }
 
+v8::Local<v8::Context> toV8Context(ScriptExecutionContext* context, DOMWrapperWorld* world)
+{
+    if (context->isDocument()) {
+        if (Frame* frame = static_cast<Document*>(context)->frame()) {
+            // FIXME: Store the DOMWrapperWorld for the main world in the v8::Context so callers
+            // that are looking up their world with DOMWrapperWorld::getWorld(v8::Context::GetCurrent())
+            // won't end up passing null here when later trying to get their v8::Context back.
+            if (!world)
+                return frame->script()->mainWorldContext();
+            return v8::Local<v8::Context>::New(frame->script()->windowShell(world)->context());
+        }
+#if ENABLE(WORKERS)
+    } else if (context->isWorkerContext()) {
+        if (WorkerScriptController* script = static_cast<WorkerContext*>(context)->script())
+            return script->context();
+#endif
+    }
+    return v8::Local<v8::Context>();
+}
+
 bool handleOutOfMemory()
 {

trunk/Source/WebCore/bindings/v8/V8Binding.h

@@ -446 +446 @@
     // Returns the context associated with a ScriptExecutionContext.
     v8::Local<v8::Context> toV8Context(ScriptExecutionContext*, const WorldContextHandle&);
+    v8::Local<v8::Context> toV8Context(ScriptExecutionContext*, DOMWrapperWorld*);
 
     // Returns the frame object of the window object associated with

trunk/Source/WebCore/bindings/v8/V8MutationCallback.cpp

@@ -39 +39 @@
     : ActiveDOMCallback(context)
     , m_callback(callback)
-    , m_worldContext(UseCurrentWorld)
+    , m_world(DOMWrapperWorld::getWorld(v8::Context::GetCurrent()))
 {
     owner->SetHiddenValue(V8HiddenPropertyName::callback(), callback);
@@ -56 +56 @@
     v8::HandleScope handleScope;
 
-    v8::Handle<v8::Context> v8Context = toV8Context(scriptExecutionContext(), m_worldContext);
+    v8::Handle<v8::Context> v8Context = toV8Context(scriptExecutionContext(), m_world.get());
     if (v8Context.IsEmpty())
         return true;

trunk/Source/WebCore/bindings/v8/V8MutationCallback.h

@@ -28 +28 @@
 
 #include "ActiveDOMCallback.h"
+#include "DOMWrapperWorld.h"
 #include "MutationCallback.h"
 #include "ScopedPersistent.h"
-#include "WorldContextHandle.h"
 #include <v8.h>
+#include <wtf/RefPtr.h>
 
 namespace WebCore {
@@ -59 +60 @@
 
     ScopedPersistent<v8::Object> m_callback;
-    WorldContextHandle m_worldContext;
+    RefPtr<DOMWrapperWorld> m_world;
 };