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Re: Threading?

From: Peter Sorotokin <psorotok@adobe.com>
Date: Sun, 12 Dec 2004 21:32:17 -0800
To: Thomas DeWeese <Thomas.DeWeese@Kodak.com>, Jon Ferraiolo <jon.ferraiolo@adobe.com>
Cc: client@evolgrafix.com, www-svg@w3.org
Message-id: <5.2.0.9.2.20041212213042.030e5d10@mailsj-v1.corp.adobe.com>

At 06:31 PM 12/12/2004 -0500, Thomas DeWeese wrote:

>Jon Ferraiolo wrote:
>
>>Although I do not believe that any standards actually document this, it 
>>is my understanding of the standard web page processing model is that you 
>>have single-threaded access to the DOM. Even with Microsoft's 
>>next-generation user interface system, XAML/Avalon, there is only one 
>>"user interface thread", even though you have have any number of other 
>>threads such as multiple threads talking to Indigo communications 
>>services. Similarly, in the standards-based world, my understanding is 
>>that you have single-threaded access to the DOM, but it is very possible 
>>to have other threads within your scripting engines, assuming the 
>>programming language supports threads; however, usually the extra threads 
>>need to access the main DOM thread one at a time.
>
>    So I'm fine with all of the above but... How do the extra
>threads access the main DOM thread?
>
>    There _must_ be a method in the DOM to give access.  You
>might look at the interface in Java for doing this with AWT:
>
>http://java.sun.com/j2se/1.3/docs/api/java/awt/EventQueue.html
>
>    The invokeLater and invokeAndWait methods.   Analogs of
>these could easily be added the the SVGSVGElement or SVGDocument
>interfaces.  One would need to carefully define the order of
>execution semantics of the methods (are they always run in
>the order submitted, may they be run 'out of order', or are
>they ordered only within one submitting thread.
>
>    These would dictate the behavior of these methods in the
>cases where they are called from the main DOM thread.

I thought that WG agreed to specifically allow SVGTimer object access from 
arbitrary threads and have a guarantee that SVGTimer invokes a timer even 
on the DOM thread. I'll check on that.

Peter


>>Jon
>>At 08:00 AM 12/11/2004, Alexander Adam wrote:
>>
>>>hi!
>>>
>>>I got a quick question about the SVG 1.2 Implementation. Is it possible to
>>>have threads in scripts? This should be seriously considered, e.g. if you
>>>want to work with a lot of data in the background.
>>>
>>>thanks!
>>>
>>>Alexander Adam
>>>Project Manager
>>>EvolGrafiX Europe
>>>http://www.evolgrafix.com - client@evolgrafix.com
>>>Phone: +49 991 3831718
>>
>
Received on Monday, 13 December 2004 05:32:26 GMT

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