[vlc-devel] [PATCH] Playlists, Dbus

[Polar Humenn]

Sorry, I screwed up the Subject again. I'm still getting used to Gmail.

On Fri, Nov 21, 2008 at 10:35 AM, Polar Humenn <polar.humenn at gmail.com> wrote:
> Laurent Aimar <fenrir at via.ecp.fr> writes:
>
>>> @@ -517,10 +523,12 @@ int playlist_PlayItem( playlist_t *p_playlist, playlist_item_t *p_item )
>>>      set_current_status_item( p_playlist, p_item );
>>>
>>>      pl_priv(p_playlist)->status.i_status = PLAYLIST_RUNNING;
>>> -
>>> +
>>> +    PL_UNLOCK;
>>>      var_SetInteger( p_playlist, "activity", i_activity +
>>>                      DEFAULT_INPUT_ACTIVITY );
>>> -
>>> +    PL_LOCK;
>>> +
>>  I really fear that they will create race conditions. You allow someone to lock
>> the playlist in the middle of a command...
>>
>>  Is the playlist deadlocking itself or a module ?
>
> Yes.   The Dbus module locks up, because Open adds Callbacks which get
> triggered when an item is added to the playlist, which calls
> TrackListChangeEdit function. The only problem is that you do NOT have
> a guarantee on the lock of the play list whenever this callback may be
> called.
>
> The idea of unlocking before any callback is called, gives us a clear
> defined semantics with which to operate, so that we always "do the
> right thing" when designing, programming, and adding playlist variable
> callbacks.
>
> Now, I see where this particular situation above may be a problem. But
> the real questions should be asked:
>
> 1. Why is the "activity" variable set at this point in the code?
>
> 2. What would put a callback on the "activity" variable?
>
> Maybe the "activity" variable should be set, and the potential
> callbacks executed, should be set later at the end of the call. For
> instance, at the end of the call where "playlist-current" is set.
>
> Cheers,
> -Polar
>
>
>
>> --
>> fenrir
>>
>>
>>
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>>
>> End of vlc-devel Digest, Vol 18, Issue 104
>> ******************************************
>>
>