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Store MutationObserver callback in a hidden property for V8

https://bugs.webkit.org/show_bug.cgi?id=102555

Patch by Elliott Sprehn <esprehn@chromium.org> on 2012-11-20
Reviewed by Adam Barth.

.:

Test for reference cycle leaks with mutation observers. There doesn't seem
to be a way to check this for v8, but if you manually run you can see if it
leaks observers.

* ManualTests/leak-cycle-observer-wrapper.html: Added.

Source/WebCore:

To prevent circular reference leaks we should store the MutationObserver
callback in a hidden property on the wrapper of the observer.

This is done by extending the code generator to support a new owner
argument to ::create() that lets you set the owner of the callback where
the hidden property should be stored.

Test: ManualTests/leak-cycle-observer-wrapper.html

* bindings/scripts/CodeGeneratorV8.pm:
(GenerateCallbackHeader):
(GenerateCallbackImplementation):
* bindings/scripts/test/V8/V8TestCallback.cpp: rebaselined.
* bindings/scripts/test/V8/V8TestCallback.h: rebaselined.
* bindings/v8/V8HiddenPropertyName.h:
* bindings/v8/custom/V8MutationObserverCustom.cpp:
(WebCore::V8MutationObserver::constructorCallback):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@135305 268f45cc-cd09-0410-ab3c-d52691b4dbfc
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1 parent 7cb9d15 commit f61a46a837e49d0e52e9a286a85d36a6dc7bbdce commit-queue@webkit.org committed Nov 20, 2012
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@@ -1,3 +1,16 @@
+2012-11-20 Elliott Sprehn <esprehn@chromium.org>
+
+ Store MutationObserver callback in a hidden property for V8
+ https://bugs.webkit.org/show_bug.cgi?id=102555
+
+ Reviewed by Adam Barth.
+
+ Test for reference cycle leaks with mutation observers. There doesn't seem
+ to be a way to check this for v8, but if you manually run you can see if it
+ leaks observers.
+
+ * ManualTests/leak-cycle-observer-wrapper.html: Added.
+
2012-11-20 Carlos Garcia Campos <cgarcia@igalia.com>
Unreviewed. Update NEWS and configure.ac for 1.11.2 release
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+
+<p>
+ Tests that reference cycles between the observer and the callback do not
+ create leaks.
+</p>
+
+<script>
+ if (window.testRunner)
+ testRunner.dumpAsText();
+
+ function leak() {
+ var observer = new WebKitMutationObserver(function() { observer.disconnect(); });
+ }
+
+ for (i=0; i < 1000; i++) leak();
+ gc();
+</script>
View
@@ -1,3 +1,28 @@
+2012-11-20 Elliott Sprehn <esprehn@chromium.org>
+
+ Store MutationObserver callback in a hidden property for V8
+ https://bugs.webkit.org/show_bug.cgi?id=102555
+
+ Reviewed by Adam Barth.
+
+ To prevent circular reference leaks we should store the MutationObserver
+ callback in a hidden property on the wrapper of the observer.
+
+ This is done by extending the code generator to support a new owner
+ argument to ::create() that lets you set the owner of the callback where
+ the hidden property should be stored.
+
+ Test: ManualTests/leak-cycle-observer-wrapper.html
+
+ * bindings/scripts/CodeGeneratorV8.pm:
+ (GenerateCallbackHeader):
+ (GenerateCallbackImplementation):
+ * bindings/scripts/test/V8/V8TestCallback.cpp: rebaselined.
+ * bindings/scripts/test/V8/V8TestCallback.h: rebaselined.
+ * bindings/v8/V8HiddenPropertyName.h:
+ * bindings/v8/custom/V8MutationObserverCustom.cpp:
+ (WebCore::V8MutationObserver::constructorCallback):
+
2012-11-20 Abhishek Arya <inferno@chromium.org>
Crash in FrameLoader::stopLoading.
@@ -3246,11 +3246,11 @@ sub GenerateCallbackHeader
push(@headerContent, <<END);
public:
- static PassRefPtr<${v8InterfaceName}> create(v8::Local<v8::Value> value, ScriptExecutionContext* context)
+ static PassRefPtr<${v8InterfaceName}> create(v8::Handle<v8::Value> value, ScriptExecutionContext* context, v8::Handle<v8::Object> owner = v8::Handle<v8::Object>())
{
ASSERT(value->IsObject());
ASSERT(context);
- return adoptRef(new ${v8InterfaceName}(value->ToObject(), context));
+ return adoptRef(new ${v8InterfaceName}(value->ToObject(), context, owner));
}
virtual ~${v8InterfaceName}();
@@ -3282,8 +3282,16 @@ END
push(@headerContent, <<END);
private:
- ${v8InterfaceName}(v8::Local<v8::Object>, ScriptExecutionContext*);
+ ${v8InterfaceName}(v8::Handle<v8::Object>, ScriptExecutionContext*, v8::Handle<v8::Object>);
+ static void weakCallback(v8::Persistent<v8::Value> wrapper, void* parameter)
+ {
+ ${v8InterfaceName}* object = static_cast<${v8InterfaceName}*>(parameter);
+ object->m_callback.Dispose();
+ object->m_callback.Clear();
+ }
+
+ // FIXME: m_callback should be a ScopedPersistent.
v8::Persistent<v8::Object> m_callback;
WorldContextHandle m_worldContext;
};
@@ -3314,16 +3322,21 @@ sub GenerateCallbackImplementation
push(@implContent, "#include <wtf/Assertions.h>\n\n");
push(@implContent, "namespace WebCore {\n\n");
push(@implContent, <<END);
-${v8InterfaceName}::${v8InterfaceName}(v8::Local<v8::Object> callback, ScriptExecutionContext* context)
+${v8InterfaceName}::${v8InterfaceName}(v8::Handle<v8::Object> callback, ScriptExecutionContext* context, v8::Handle<v8::Object> owner)
: ActiveDOMCallback(context)
, m_callback(v8::Persistent<v8::Object>::New(callback))
, m_worldContext(UseCurrentWorld)
{
+ if (!owner.IsEmpty()) {
+ owner->SetHiddenValue(V8HiddenPropertyName::callback(), callback);
+ m_callback.MakeWeak(this, &${v8InterfaceName}::weakCallback);
+ }
}
${v8InterfaceName}::~${v8InterfaceName}()
{
- m_callback.Dispose();
+ if (!m_callback.IsEmpty())
+ m_callback.Dispose();
}
END
@@ -39,16 +39,21 @@
namespace WebCore {
-V8TestCallback::V8TestCallback(v8::Local<v8::Object> callback, ScriptExecutionContext* context)
+V8TestCallback::V8TestCallback(v8::Handle<v8::Object> callback, ScriptExecutionContext* context, v8::Handle<v8::Object> owner)
: ActiveDOMCallback(context)
, m_callback(v8::Persistent<v8::Object>::New(callback))
, m_worldContext(UseCurrentWorld)
{
+ if (!owner.IsEmpty()) {
+ owner->SetHiddenValue(V8HiddenPropertyName::callback(), callback);
+ m_callback.MakeWeak(this, &V8TestCallback::weakCallback);
+ }
}
V8TestCallback::~V8TestCallback()
{
- m_callback.Dispose();
+ if (!m_callback.IsEmpty())
+ m_callback.Dispose();
}
// Functions
@@ -35,11 +35,11 @@ class ScriptExecutionContext;
class V8TestCallback : public TestCallback, public ActiveDOMCallback {
public:
- static PassRefPtr<V8TestCallback> create(v8::Local<v8::Value> value, ScriptExecutionContext* context)
+ static PassRefPtr<V8TestCallback> create(v8::Handle<v8::Value> value, ScriptExecutionContext* context, v8::Handle<v8::Object> owner = v8::Handle<v8::Object>())
{
ASSERT(value->IsObject());
ASSERT(context);
- return adoptRef(new V8TestCallback(value->ToObject(), context));
+ return adoptRef(new V8TestCallback(value->ToObject(), context, owner));
}
virtual ~V8TestCallback();
@@ -55,8 +55,16 @@ class V8TestCallback : public TestCallback, public ActiveDOMCallback {
virtual bool callbackRequiresThisToPass(Class8* class8Param, ThisClass* thisClassParam);
private:
- V8TestCallback(v8::Local<v8::Object>, ScriptExecutionContext*);
+ V8TestCallback(v8::Handle<v8::Object>, ScriptExecutionContext*, v8::Handle<v8::Object>);
+ static void weakCallback(v8::Persistent<v8::Value> wrapper, void* parameter)
+ {
+ V8TestCallback* object = static_cast<V8TestCallback*>(parameter);
+ object->m_callback.Dispose();
+ object->m_callback.Clear();
+ }
+
+ // FIXME: m_callback should be a ScopedPersistent.
v8::Persistent<v8::Object> m_callback;
WorldContextHandle m_worldContext;
};
@@ -37,6 +37,7 @@ namespace WebCore {
#define V8_HIDDEN_PROPERTIES(V) \
V(attributeListener) \
+ V(callback) \
V(detail) \
V(document) \
V(domStringMap) \
@@ -61,11 +61,11 @@ v8::Handle<v8::Value> V8MutationObserver::constructorCallback(const v8::Argument
return setDOMException(TYPE_MISMATCH_ERR, args.GetIsolate());
ScriptExecutionContext* context = getScriptExecutionContext();
+ v8::Handle<v8::Object> wrapper = args.Holder();
- RefPtr<MutationCallback> callback = V8MutationCallback::create(arg, context);
+ RefPtr<MutationCallback> callback = V8MutationCallback::create(arg, context, wrapper);
RefPtr<MutationObserver> observer = MutationObserver::create(callback.release());
- v8::Handle<v8::Object> wrapper = args.Holder();
V8DOMWrapper::createDOMWrapper(observer.release(), &info, wrapper);
return wrapper;
}

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