82845 - Add private data type flags for JSContext

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P3)

Description

[Johnny Stenback (:jst)]

Currently there's no way to know anything about the type of private data held in
a JSContext, all you get is a void*. This makes it unsafe to call
JS_GetContextPrivate() and cast the void* to something like a nsISupports* and
then calling QuertyInterface() on that pointer. We need something like the
JSClass->flags and a set of flags (one of which should be equvalent of
JSCLASS_PRIVATE_IS_NSISUPPORTS) to bullet proof code that accesses the private
data in JSContext's.

Maybe something like:

extern JS_PUBLIC_API(uint32)
JS_GetContextFlags(JSContext *cx);

Comment 1

[Brendan Eich [:brendan]]

Too easy not to do soon.  Hey, maybe I'll sneak this into the FastLoad branch.

/be

Comment 2

[Brendan Eich [:brendan]]

Attachment: proposed fix

Comment 3

[Brendan Eich [:brendan]]

I don't feel the need to bloat JSContext with yet another word when so many bits
remain unallocated from cx->options.  Thus, JSOPTION_PRIVATE_IS_NSISUPPORTS and
code to test and set it in dom/src/base and js/src/xpconnect/src.  The changes
to nsGlobalWindow.cpp are :: madness before JS_Foo() and a needed initializer
for a cx variable that could be used before set (in the unlikely event that the
xpconnect per-thread context stack is unavailable).

Cc'ing review pals.

/be

Comment 4

[Chris Waterson]

cool. r/sr=waterson

Comment 5

[Johnny Stenback (:jst)]

sr=jst, I like it!

Comment 6

[Brendan Eich [:brendan]]

Fixed.

Comment 7

[Phil Schwartau]

Marking Verified -