[webkit-dev] WebCore: Exposing exceptions through WebFrameImpl::executeScriptAndReturnValue and ScriptController::executeScript.

[Yury Semikhatsky]

On Wed, Dec 22, 2010 at 7:22 PM, Tom Rathbone <tom.rathbone at gmail.com>wrote:

> From my experiments calling executeScriptAndReturnValue "function
> foo() { } foo();" will also return an empty handle meaning that this
> can't reliably be used to detect errors.  Is there another way to
> distinguish non values from errors?
>
I see, the problem is that 'undefined' value is converted into an empty
ScriptValue in ScriptController::evaluate:
http://codesearch.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.cpp&q=::executeScriptAndReturnValue%5C(&gs=cpp:WebCore::ScriptController::executeScript(const%2520WebCore::ScriptSourceCode%2520&amp;,%2520enum%2520ShouldAllowXSS)@chrome/trunk/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.h%257Cdecl&gsn=executeScript&d=5&l=260<http://codesearch.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.cpp&q=::executeScriptAndReturnValue%5C(&gs=cpp:WebCore::ScriptController::executeScript(const%2520WebCore::ScriptSourceCode%2520&,%2520enum%2520ShouldAllowXSS)@chrome/trunk/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.h%257Cdecl&gsn=executeScript&d=5&l=260>

Not sure what this conversion is used for.

Yury




>
> On Wed, Dec 22, 2010 at 2:35 PM, Yury Semikhatsky <yurys at chromium.org>
> wrote:
> > Hi Tom,
> > In case of uncaught JS exception returned v8::Handle will always be empty
> > (v8::Handle<v8::Value>::IsEmpty() will return true) while in case of
> > successful
> > evaluation the result is always non-empty. Also uncaught JS exception
> will
> > be
> > reported to the console object(see Console.cpp) which will propagate them
> > to
> > InspectorController and ChromeClient.
> > Thanks,
> > Yury
> >
> > On Wed, Dec 22, 2010 at 12:58 PM, Tom Rathbone <tom.rathbone at gmail.com>
> > wrote:
> >>
> >> Hi Guys,
> >>
> >> I was wondering if it would be possible to expose v8 exceptions
> >> through WebFrameImpl::executeScriptAndReturnValue and
> >> ScriptController::executeScript, perhaps as an output reference
> >> argument.
> >>
> >> The effected methods would be:
> >>
> >> v8::Handle<v8::Value> WebFrameImpl::executeScriptAndReturnValue(const
> >> WebScriptSource& source)
> >> ScriptValue ScriptController::executeScript(const ScriptSourceCode&
> >> sourceCode, ShouldAllowXSS shouldAllowXSS)
> >> ScriptValue ScriptController::evaluate(const ScriptSourceCode&
> >> sourceCode, ShouldAllowXSS shouldAllowXSS)
> >> v8::Local<v8::Value> V8Proxy::evaluate(const ScriptSourceCode& source,
> >> Node* node)
> >>
> >> If I've read the source correctly V8 exceptions are caught in
> >> V8Proxy::evaluate and swallowed.  This means clients calling
> >> executeScriptAndReturnValue have no easy way of determining what went
> >> wrong or of responding to script errors.
> >>
> >> Maybe...
> >>
> >> v8::Handle<v8::Value> WebFrameImpl::executeScriptAndReturnValue(const
> >> WebScriptSource& source, bool& exceptionReturned)
> >>
> >> If others think these changes are worthwhile then I'll have a go at
> >> crafting a patch.
> >>
> >> Thanks,
> >>
> >> Tom.
> >> _______________________________________________
> >> webkit-dev mailing list
> >> webkit-dev at lists.webkit.org
> >> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
> >
> >
>
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