About object Finalize callback

[wenbin wang]

When a object in javscript file like "SecondHand" does exist, an object will be constructed.
But when the object destructed,
or when the finalize callback is called?
Please tell me the detail about that in js_script_context.cc.
Thanks very much.

[James Su]

The javascript object will be garbage collected if it's not used anymore.

Regards

James Su

2010/1/7 wenbin wang <wbwan...@gmail.com>

Thanks very much.

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[wbwang1985]

But I can't see Finalizecallback called in debug information, 

in which function some release work must be done.

 

So can you tell me when Finalizecallback be called?

 

2010-01-07

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wbwang1985

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发件人： James Su

发送时间： 2010-01-07  10:53:59

收件人： google-gadgets-for-linux-user

抄送：

主题： Re: [ggl-user] About object Finalize callback

[James Su]

2010/1/7 wbwang1985 <wbwan...@gmail.com>

But I can't see Finalizecallback called in debug information, 

in which function some release work must be done.

 

So can you tell me when Finalizecallback be called?

Which function in which file?

[wenbin wang]

FinalizeCallback in js_script_context.cc.\
Thanks.

[James Su]

Do you mean extensions/webkit_script_runtime/js_script_context.cc? You may refer to this document for details. In short, this will be called when the object is prepared for garbage collection. Please search on Google if you want to know what is garbage collection and when it will occur.

[wenbin wang]

Yes. This will be called when the object is prepared for garbage collection, but it will not be called during the program running.  It causes the memory leak until memory is exhausted.
If you can tell me when FinalizeCallback called,  I will be very grateful about that! Thanks.

[Xianzhu Wang]

"SecondHand" is a JS wrapper of a native object (an ImageElement
object). The wrapper is created when it is first accessed, and will
have the same life time as the backed native object. This won't cause
memory-leak because this is not accumulative.

2010/1/7 wenbin wang <wbwan...@gmail.com>:

> Yes. This will be called when the object is prepared for garbage collection,
> but it will not be called during the program running. It causes the memory
> leak until memory is exhausted.
> If you can tell me when FinalizeCallback called, I will be very grateful
> about that! Thanks.
>

> 2010/1/7 James Su <jame...@gmail.com>

>>
>> Do you mean extensions/webkit_script_runtime/js_script_context.cc? You may
>> refer to this document for details. In short, this will be called when the
>> object is prepared for garbage collection. Please search on Google if you
>> want to know what is garbage collection and when it will occur.
>> Regards
>> James Su
>>
>> 2010/1/7 wenbin wang <wbwan...@gmail.com>
>>>
>>> FinalizeCallback in js_script_context.cc.\
>>> Thanks.
>>>

>>> 2010/1/7 James Su <jame...@gmail.com>

[James Su]

It's must be a bug if it's not called at all. Please tell us how did you produce this problem.

[wbwang1985]

But when the backed native object is destructed, how the wrapper be telled and destructs itself ?

Thanks very much.

 

 

 

2010-01-07

---

wbwang1985

---

发件人： Xianzhu Wang

发送时间： 2010-01-07  12:23:07

收件人： google-gadgets-for-linux-user

抄送：

主题： Re: Re: [ggl-user] About object Finalize callback

[wenbin wang]

The map of wrapper is accumulated.

2010/1/7 wbwang1985 <wbwan...@gmail.com>

But when the backed native object is destructed, how the wrapper be telled and destructs itself ?

Thanks very much.

 

 

 

2010-01-07

---

wbwang1985

---

发件人： Xianzhu Wang

发送时间： 2010-01-07  12:23:07

收件人： google-gadgets-for-linux-user

抄送：

主题： Re: Re: [ggl-user] About object Finalize callback

"SecondHand" is a JS wrapper of a native object (an ImageElement

object). The wrapper is created when it is first accessed, and will

have the same life time as the backed native object. This won't cause

memory-leak because this is not accumulative.

2010/1/7 wenbin wang <wbwan...@gmail.com>:

> Yes. This will be called when the object is prepared for garbage collection,

> but it will not be called during the program running.  It causes the memory

> leak until memory is exhausted.

> If you can tell me when FinalizeCallback called,  I will be very grateful

> about that! Thanks.

>

[Xianzhu Wang]

The native objects are reference counted. The reference (which was
added when the wrapper is created) to the wrapper will be removed when
the native object's reference count reaches 0, and the wrapper will be
removed from the map. Then during GC, the wrapper will be finalized if
there is no other reference from live JS objects to the wrapper.

2010/1/7 wenbin wang <wbwan...@gmail.com>:

> The map of wrapper is accumulated.
>
> 2010/1/7 wbwang1985 <wbwan...@gmail.com>
>>
>> But when the backed native object is destructed, how the wrapper be telled
>> and destructs itself ?
>> Thanks very much.
>>
>>
>>
>> 2010-01-07
>> ________________________________
>> wbwang1985
>> ________________________________
>> 发件人： Xianzhu Wang
>> 发送时间： 2010-01-07 12:23:07
>> 收件人： google-gadgets-for-linux-user
>> 抄送：
>> 主题： Re: Re: [ggl-user] About object Finalize callback
>> "SecondHand" is a JS wrapper of a native object (an ImageElement
>> object). The wrapper is created when it is first accessed, and will
>> have the same life time as the backed native object. This won't cause
>> memory-leak because this is not accumulative.
>> 2010/1/7 wenbin wang <wbwan...@gmail.com>:
>>
>> > > Yes. This will be called when the object is prepared for garbage collection,
>>
>> > > but it will not be called during the program running. It causes the memory
>> > leak until memory is exhausted.
>>
>> > > If you can tell me when FinalizeCallback called, I will be very grateful
>> > about that! Thanks.
>> >

>> > 2010/1/7 James Su <jame...@gmail.com>

>> >>
>>
>> >> >> Do you mean extensions/webkit_script_runtime/js_script_context.cc? You may
>>
>> >> >> refer to this document for details. In short, this will be called when the
>>
>> >> >> object is prepared for garbage collection. Please search on Google if you
>> >> want to know what is garbage collection and when it will occur.
>> >> Regards
>> >> James Su
>> >>
>> >> 2010/1/7 wenbin wang <wbwan...@gmail.com>
>> >>>
>> >>> FinalizeCallback in js_script_context.cc.\
>> >>> Thanks.
>> >>>

>> >>> 2010/1/7 James Su <jame...@gmail.com>

[Xianzhu Wang]

Please let us know if you have seen actual memory leaks. Thanks!

2010/1/7 Xianzhu Wang <phni...@gmail.com>: