Expose APIs for detecting boxed primitives, native errors and Math.

Expose APIs for detecting boxed primitives, native errors and Math.

While implementing structured clone I found that I need support
for detecting and creating objects using the builtin Number, String
and Boolean constructors; this CL adds this support. I also need
to be able to detect entities of "native object type (e.g., Error)",
hence the new IsNativeError() calls.


(ref: http://www.whatwg.org/specs/web-apps/current-work/multipage/urls.html#safe-passing-of-structured-data)

Patch by Luke Zarko.

Committed: http://code.google.com/p/v8/source/detail?r=8653

[zarko, 2011-07-12 18:28:01]

Please have a look if you get a chance!

Thanks,
  Luke

[Vyacheslav Egorov (Chromium), 2011-07-12 18:30:37]

Redirecting to Mads.

API seems reasonable (and there seems to be no way around introducing it).

[Vyacheslav Egorov (Chromium), 2011-07-12 20:38:12]

http://codereview.chromium.org/7344013/diff/1/include/v8.h
File include/v8.h (right):

http://codereview.chromium.org/7344013/diff/1/include/v8.h#newcode937
include/v8.h:937: V8EXPORT bool IsBoxedBoolean() const;
Lets call them IsXXXObject instead of IsBoxedXXX.

http://codereview.chromium.org/7344013/diff/1/include/v8.h#newcode1778
include/v8.h:1778: class BoxedNumber : public Object {
XXXObject

http://codereview.chromium.org/7344013/diff/1/src/api.cc
File src/api.cc (right):

http://codereview.chromium.org/7344013/diff/1/src/api.cc#newcode2228
src/api.cc:2228: bool Value::IsMath() const {
Lets pull IsMath() from API for now.

http://codereview.chromium.org/7344013/diff/1/src/factory.cc
File src/factory.cc (right):

http://codereview.chromium.org/7344013/diff/1/src/factory.cc#newcode249
src/factory.cc:249: isolate->heap()->AllocateJSObject(constructor),
constructor will be "dead variable" if GC happens.

you need to wrap constructor into Handle.

(constructor object can't die, but potentially can be relocated)

better still: there is already a Object::ToObject and Factory::ToObject methods
which do exactly what you need.

So I think you can use them to implement your API. so Factory::NewBoxedXXX are
unnecessary.

[zarko, 2011-07-12 21:42:06]

Thanks for the tips! I went back and forth a bit about renaming the locals in
the unit tests as well but felt that they were clearer as-is.

http://codereview.chromium.org/7344013/diff/1/include/v8.h
File include/v8.h (right):

http://codereview.chromium.org/7344013/diff/1/include/v8.h#newcode937
include/v8.h:937: V8EXPORT bool IsBoxedBoolean() const;
On 2011/07/12 20:38:12, Vyacheslav Egorov wrote:
> Lets call them IsXXXObject instead of IsBoxedXXX.

Done.

http://codereview.chromium.org/7344013/diff/1/include/v8.h#newcode1778
include/v8.h:1778: class BoxedNumber : public Object {
On 2011/07/12 20:38:12, Vyacheslav Egorov wrote:
> XXXObject

Done.

http://codereview.chromium.org/7344013/diff/1/src/api.cc
File src/api.cc (right):

http://codereview.chromium.org/7344013/diff/1/src/api.cc#newcode2228
src/api.cc:2228: bool Value::IsMath() const {
On 2011/07/12 20:38:12, Vyacheslav Egorov wrote:
> Lets pull IsMath() from API for now.

Done.

http://codereview.chromium.org/7344013/diff/1/src/factory.cc
File src/factory.cc (right):

http://codereview.chromium.org/7344013/diff/1/src/factory.cc#newcode249
src/factory.cc:249: isolate->heap()->AllocateJSObject(constructor),
On 2011/07/12 20:38:12, Vyacheslav Egorov wrote:
> constructor will be "dead variable" if GC happens.
> 
> you need to wrap constructor into Handle.
> 
> (constructor object can't die, but potentially can be relocated)
> 
> better still: there is already a Object::ToObject and Factory::ToObject
methods
> which do exactly what you need.
> 
> So I think you can use them to implement your API. so Factory::NewBoxedXXX are
> unnecessary.

Done.

[Vyacheslav Egorov (Chromium), 2011-07-13 09:10:17]

LGTM

I will adjust comments and land.

http://codereview.chromium.org/7344013/diff/3007/include/v8.h
File include/v8.h (right):

http://codereview.chromium.org/7344013/diff/3007/include/v8.h#newcode935
include/v8.h:935: * Returns true if this value is an instance of the Boolean
constructor.
I suggest clearer wording:

"Returns true if this value is XXX object"

notion of XXX object is defined in ECMA-262 (e.g.
http://es5.github.com/#x4.3.15).