Bug 116844 – Deleting static properties defined with the JSC API should work

• Status: NEW
• Component: JavaScriptCore

[Mark Hahnenberg]

Currently it is impossible to delete static properties defined via the C API from API objects.

[Mark Hahnenberg]

Created attachment 203013 [details]
Patch

[Darin Adler]

Comment on attachment 203013 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=203013&action=review

> Source/JavaScriptCore/ChangeLog:21
> +        (JSC::::getOwnPropertySlot):

The script screws up parsing these function names. You should put in the JSCallbackObject part by hand if you are leaving these lines in.

> Source/JavaScriptCore/API/JSCallbackObject.h:82
> +        if (!m_deletedStaticProperties)
> +            return false;
> +        return m_deletedStaticProperties->contains(name);

I like to write these with && instead of an early return.

[Darin Adler]

Is there a similar issue for the Objective-C API?

[Mark Hahnenberg]

(In reply to comment #3)
> Is there a similar issue for the Objective-C API?

I don't think so. We don't really have a concept of static functions in the Objective-C API. All properties are real properties on the underlying JS wrapper objects. The accessors added to the JS wrappers for Objective-C @properties are set to be "configurable" which means they can be deleted.

[Geoffrey Garen]

Comment on attachment 203013 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=203013&action=review

This patch will remove the *interface* for a static property in response to a delete request -- I don't think that's quite what our client wanted. They wanted an object that could implement a custom property, but store the backing for that property in normal object backing, and then use delete to remove it. Maybe we need to clear this up with them.

> Source/JavaScriptCore/API/JSCallbackObjectFunctions.h:393
> +                    thisObject->m_callbackObjectData->deleteStaticProperty(name);
> +                    bool result = Parent::deleteProperty(thisObject, exec, propertyName);
> +                    ASSERT(result);
> +                    return result;

This isn't quite right. We should only call through to Parent::deleteProperty() if we did not find a static property to delete, and our return value should depend on whether we found anything to delete.

> Source/JavaScriptCore/API/JSCallbackObjectFunctions.h:406
> +                    thisObject->m_callbackObjectData->deleteStaticProperty(name);
> +                    bool result = Parent::deleteProperty(thisObject, exec, propertyName);
> +                    ASSERT(result);
> +                    return result;

Ditto.