Implement BlindReference object and provide couple of liveedit-specific structures

Implement BlindReference object and provide couple of liveedit-specific structures

Committed: http://code.google.com/p/v8/source/detail?r=3943

[Peter Rybin, 2010-02-22 01:48:47]

Hi Soren

Recently I have been porting liveedit implementation from C++ to JavaScript.
However some functions must stay in C++. This small CL is about data exchanging
between C++ and JS.

1. It provides 2 structures for C++, that are backed by JSArray object. I did it
very simple and without touching other parts of V8 (like objects.h).

2. It also introduces BlindReference JavaScript type; I need to temporary give
some sensitive objects (SharedFunctionInfo and Code) to JavaScript. JavaScript
should hold them and then give them back to C++. I think it's good to sanitize
these objects by BlindReference wrapper.
In particular, I tried to run my liveedit JS implementation under debugger (!),
and debugger became crazy on seeing SharedFunctionInfo or Code.

Peter

[Søren Thygesen Gjesse, 2010-02-22 10:36:56]

LGTM

http://codereview.chromium.org/650127/diff/1001/1002
File src/bootstrapper.cc (right):

http://codereview.chromium.org/650127/diff/1001/1002#newcode1054
src/bootstrapper.cc:1054: // Builtin function for BlindReference -- a
JSValue-based object,
Could we find a better name that BlindReference? How about OpaqueReference,
HiddenReference or HiddenObjectReference?

http://codereview.chromium.org/650127/diff/1001/1004
File src/liveedit.cc (right):

http://codereview.chromium.org/650127/diff/1001/1004#newcode132
src/liveedit.cc:132: int GetSmiField(int field_position) {
This functions does not return a smi, so ither it should have a different name
or return a Smi. Maybe GetSmiValueField, maybe remove the Field postfix for all
these functions.

http://codereview.chromium.org/650127/diff/1001/1004#newcode140
src/liveedit.cc:140: 
This comment mentions SharedFunctionInfo. Have the comments for the two classes
been mixed up?

http://codereview.chromium.org/650127/diff/1001/1004#newcode151
src/liveedit.cc:151: SetField(kFunctionNameOffset_, name);
Why is the handle scope not at the top?

http://codereview.chromium.org/650127/diff/1001/1004#newcode199
src/liveedit.cc:199: 
Are the name, start_position and end_poition not available in the shared
function info?

http://codereview.chromium.org/650127/diff/1001/1004#newcode204
src/liveedit.cc:204: SetField(kSharedInfoOffset_, info_holder);
Why is the handle scope not at the top?

[Peter Rybin, 2010-02-24 19:33:29]

http://codereview.chromium.org/650127/diff/1001/1002
File src/bootstrapper.cc (right):

http://codereview.chromium.org/650127/diff/1001/1002#newcode1054
src/bootstrapper.cc:1054: // Builtin function for BlindReference -- a
JSValue-based object,
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> Could we find a better name that BlindReference? How about OpaqueReference,
> HiddenReference or HiddenObjectReference?

The easiest thing to do.
OpaqueReference it is.

http://codereview.chromium.org/650127/diff/1001/1004
File src/liveedit.cc (right):

http://codereview.chromium.org/650127/diff/1001/1004#newcode132
src/liveedit.cc:132: int GetSmiField(int field_position) {
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> This functions does not return a smi, so ither it should have a different name
> or return a Smi. Maybe GetSmiValueField, maybe remove the Field postfix for
all
> these functions.

GetSmiValueField
Done

http://codereview.chromium.org/650127/diff/1001/1004#newcode140
src/liveedit.cc:140: 
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> This comment mentions SharedFunctionInfo. Have the comments for the two
classes
> been mixed up?

Oh, I'm sorry.
Done

http://codereview.chromium.org/650127/diff/1001/1004#newcode151
src/liveedit.cc:151: SetField(kFunctionNameOffset_, name);
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> Why is the handle scope not at the top?

Done.

http://codereview.chromium.org/650127/diff/1001/1004#newcode199
src/liveedit.cc:199: 
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> Are the name, start_position and end_poition not available in the shared
> function info?

I wanted this setter method and the class itself to be as stupid as possible. It
stores some fields and it provides setters/getters as needed. Someone else
should be preparing data.

If it looks really out of V8 style, please say so; I would fix it.

http://codereview.chromium.org/650127/diff/1001/1004#newcode204
src/liveedit.cc:204: SetField(kSharedInfoOffset_, info_holder);
On 2010/02/22 10:36:56, Søren Gjesse wrote:
> Why is the handle scope not at the top?

Done.