[webkit-dev] JavaScript bindings changed to call scriptExecutionContext virtual function?

Maciej Stachowiak mjs at apple.com
Sun Aug 2 08:44:44 PDT 2009

On Aug 2, 2009, at 2:44 AM, Adam Barth wrote:

> On Sun, Aug 2, 2009 at 2:09 AM, Darin Adler<darin at apple.com> wrote:
>> On Aug 2, 2009, at 2:05 AM, Adam Barth wrote:
>>> In any case:
>>>    https://bugs.webkit.org/show_bug.cgi?id=27931
>>> I'll have a patch shortly. Please let me know if there are other  
>>> call
>>> sites you'd like changed.
>> Thanks! Once you pointed out this was not due to a recent change, I  
>> had
>> resolved to fix it myself, but I’m glad you’re going to tackle it.
>> Generally speaking no call site that has a Node* should call
>> scriptExecutionContext(). So rather than listing the call sites I  
>> want
>> changed, I’d instead suggest that we make  
>> Node::scriptExecutionContext()
>> private and then make sure no Node member functions or members  
>> functions of
>> friend classes call the function.
> I tried this, and it looks like there are a bunch of instances in the
> generated bindings that weren't found by cscope.  Basically, this line
> of CodeGeneartorJS needs to know whether impl is a subclass of Node*:
> push(@implContent, "    JSDOMGlobalObject* globalObject =
> toJSDOMGlobalObject(imp->scriptExecutionContext());\n");
> It's a bit too late at night for me to wrap my mind around the code
> generator, but that's a clear next step.

I think the code generator doesn't try to track the whole class  
hierarchy. Probably a simpler way to achieve the goal here would be  
with overloaded inline functions, so the C++ type system can do the  

inline ScriptExecutionContext* scriptExecutionContext(EventTarget* et)
     return et->scriptExecutionContext();

inline Document* scriptExecutionContext(Node* n)
     return n->document();

Alternately, EventTarget could have an inline nonvirtual member  
function that calls the virtual member function, and Node could  
override it with one that calls document().


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