Problems with "end" callback in Python

[James Simmons]

Hynek,

Thanks for looking at this.  I tried your code change and you're right, 
it does look like everything works fine if you don't use 
gobject.timeout_add().  Unfortunately, I need that code or something 
else that can generate events at regular intervals so I step through the 
words on the page without blocking input.  If anyone on the mailing list 
has ideas I'd love to hear them.

Thanks,

James Simmons


Hynek Hanke wrote:

>
>> The code is attached.  This is not an OLPC Activity but a standalone 
>> program I use to try out new features 
>
> Hello James,
>
> I have tried to run the code you've sent and I can reliably reproduce 
> the issue. I believe it has something to do with the way how you call 
> speechd.client.speak() from inside the gtk loop, because outside of 
> it, everything works normally (even in your application).
>
> I'm not familiar with PyGTK however, so I don't see what exactly is 
> going wrong. I'll try to describe my findings in hope you or someone 
> else will have someidea.
>
> As you describe, in your program, the SSIP Python interface often 
> fails to deliver a callback to the client application (in fact, it 
> freezes and no other communication with Speech Dispatcher is 
> possible). The exact reason is that in  self._socket.recv(1024) 
> (socket.socket.recv()) fails to return although the logs of Speech 
> Dispatcher prove some new data have been written to the socket.
>
> I found that this happens when cb_next_word is
> called as a callback from keypress_cb() via
>  timeout_id = gobject.timeout_add(100, self.next_word_cb)
> but it doesn't happen, if I call it directly (around line 75):
>
>   self.karaoke = True
>                self.finished_flag = True
>                #timeout_id = gobject.timeout_add(100, 
> self.next_word_cb)                                               
>                while True:
>                    self.next_word_cb()
>                    time.sleep(0.1);
>            return True
>
> This variant will reliably speak the whole document word-by-word with 
> all the expected callbacks received.
>
> Another interesting observation is that the mentioned 
> _socket.recv(1024) returns and correctly receives all the pending 
> callbacks just after I hit CTRL-C on the python interpreter running 
> ReadETextsActivity.py and thus kill the main program thread.
>
> Now, the _socket.recv() function in the python speechd library runs in 
> a separate thread that is being launched from the Client object 
> constructor. So apparently gobject.timeout_add() somehow disturbs 
> socket opperations in other threads.
>
> It seems really strange to me and quite unlikely that the python 
> bindings themselves would be responsible.
>
> With regards,
> Hynek Hanke
>
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