On 2015/01/28 10:52:56, Yang wrote:
On 2015/01/28 09:47:30, Yang wrote:
> I will need some more convincing.
>
> Why is this change necessary? The way I see it, you need a way to
attach a
> boolean metadata to script objects, and retrieve that piece of metadata
both
via
> API and in Javascript. The content of that metadata is not interesting
to
V8,
as
> it only passes that through.
>
> There are better ways to do this. Script objects are wrapped in JSValue
objects,
> which are JSObjects. As such, you can just manipulate them as normal
Javascript
> objects. You could
> 1) Attach a property to the script object to contain that metadata. If
that
> property has to be hidden, you can simply use a Symbol as property
name. (It
> seems to me that this is not a requirement, given that you implemented
the
> accessor).
> 2) Use a WeakMap to map script object to the metadata. This is virtually
> equivalent to (1).
>
> Either way, there is no need to make this intrusive change to V8.
>
> Btw. this should actually be done for is_shared_cross_origin as well.
>
> https://codereview.chromium.org/879553002/diff/60001/src/accessors.cc
> File src/accessors.cc (right):
>
>
https://codereview.chromium.org/879553002/diff/60001/src/accessors.cc#newcode794
> src/accessors.cc:794: void Accessors::ScriptIsDebuggerScriptGetter(
> Why is this necessary? I don't see it for the is_shared_cross_origin
flag.
Upon closer inspection it seems to me that you would need to get the
script
object from the message to be able to use the property. I propose exposing
that
and deprecate ScriptOrigin. I found some bugs in the way we return
ScriptOrigin
values and it just seems to me that there is a lot of redundancy.
ScriptOrigin
was intended to pass a set of values to V8, not return from it.
The way we use script metadata from Script/ScriptOrigin in DevTools debugger
doesn't require it to be stored in a JSObject and to be accessible from
javascript. Access that data in DebuggerScript.js [1] just to read the
fields
later and serialize them as a C++ structure [2]. I don't see why we cannot
pass
v8::Script or something that would expose accessors to the data stored in
Script
object internally. That would break debug-debugger.js but if we want to get
away
from it towards a better defined C++ API that would be right direction.
[1]
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/bindings/core/v8/DebuggerScript.js&q=debuggerscript.&sq=package:chromium&type=cs&l=201
[2]
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/bindings/core/v8/ScriptDebugServer.cpp&sq=package:chromium&type=cs&l=595&rcl=1422343153
https://codereview.chromium.org/879553002/
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