Bug 227962 – Check for out of memory in JSC::globalFuncEscape() and JSC::globalFuncUnescape().

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Mark Lam]

rdar://78392251

[Mark Lam]

Created attachment 433514 [details]
proposed patch.

[Yusuke Suzuki]

Comment on attachment 433514 [details]
proposed patch.

View in context: https://bugs.webkit.org/attachment.cgi?id=433514&action=review

r=me

> Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:616
> +            return vm.smallStrings.emptyString();

Why not returning `{ }`?

> Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:679
> +            return vm.smallStrings.emptyString();

Why not returning `{ }` ?

[Mark Lam]

(In reply to Yusuke Suzuki from comment #2)
> Comment on attachment 433514 [details]
> proposed patch.
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=433514&action=review
> 
> r=me

Thanks for the review.

> > Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:616
> > +            return vm.smallStrings.emptyString();
> 
> Why not returning `{ }`?
> 
> > Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:679
> > +            return vm.smallStrings.emptyString();
> 
> Why not returning `{ }` ?

Because the return value is for a callback called from toStringView().  I gave returning { } a try and this is what I get:

./runtime/JSGlobalObjectFunctions.cpp:617:20: error: cannot deduce lambda return type from initializer list
            return { };
                   ^~~
./runtime/JSGlobalObjectFunctions.cpp:580:28: error: no matching function for call to 'toStringView'
    return JSValue::encode(toStringView(globalObject, callFrame->argument(0), [&] (StringView view) {
                           ^~~~~~~~~~~~

I'll just stick with returning the empty string for simplicity.

[Mark Lam]

(In reply to Mark Lam from comment #3)
> > > Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:616
> > > +            return vm.smallStrings.emptyString();
> > 
> > Why not returning `{ }`?
...
> Because the return value is for a callback called from toStringView().  I
> gave returning { } a try and this is what I get:
> 
> ./runtime/JSGlobalObjectFunctions.cpp:617:20: error: cannot deduce lambda
> return type from initializer list
>             return { };
>                    ^~~

On second thought, I can explicitly declare the lambdas as returning JSString*.  It will result in a roundabout way of returning an empty JSValue() on 64-bit and a null cell JSValue on 32-bit ... which is kind of inconsistent, but we already apply this treatment when throwing exceptions elsewhere in the code.

I'll just do that.

[Mark Lam]

Landed in r279915: <http://trac.webkit.org/r279915>.