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MidiAlsaSeq: improved MIDI event polling loop

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Use poll() with a finite timeout so we can quit the thread properly
without manually writing stuff into the pipe.

Check for pending events at the beginning of the loop so we can't end up
in an endless loop.

Furthermore check return value of snd_seq_event_input() and get out of
loop if it indicates an error.
This commit is contained in:
Tobias Doerffel
2009-08-14 12:13:33 +02:00
parent 295b332650
commit 9d811bf080
1 changed files with 20 additions and 11 deletions
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31
src/core/midi/MidiAlsaSeq.cpp
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@@ -36,6 +36,8 @@
#ifdef LMMS_HAVE_ALSA
const int EventPollTimeOut = 250;
MidiAlsaSeq::MidiAlsaSeq() :
MidiClient(),
@@ -95,10 +97,7 @@ MidiAlsaSeq::~MidiAlsaSeq()
if( isRunning() )
{
m_quit = true;
// wake up input queue
if( write( m_pipe[1], "\n", 1 ) )
/* fix warning */;
wait( 1000 );
wait( EventPollTimeOut*2 );
snd_seq_stop_queue( m_seqHandle, m_queueID, NULL );
snd_seq_free_queue( m_seqHandle, m_queueID );
@@ -405,26 +404,36 @@ void MidiAlsaSeq::run()
while( m_quit == false )
{
if( poll( pollfd_set, pollfd_count, -1 ) == -1 )
int pollRet = poll( pollfd_set, pollfd_count, EventPollTimeOut );
if( pollRet == 0 )
{
continue;
}
else if( pollRet == -1 )
{
// gdb may interrupt the poll
if( errno == EINTR )
{
continue;
}
perror( __FILE__ ": poll" );
qCritical( "error while polling ALSA sequencer handle" );
break;
}
// shutdown?
if( pollfd_set[0].revents )
if( m_quit )
{
break;
}
do // while event queue is not empty
// while event queue is not empty
while( snd_seq_event_input_pending( m_seqHandle, true ) > 0 )
{
snd_seq_event_t * ev;
snd_seq_event_input( m_seqHandle, &ev );
if( snd_seq_event_input( m_seqHandle, &ev ) < 0 )
{
break;
}
MidiPort * dest = NULL;
for( int i = 0; i < m_portIDs.size(); ++i )
@@ -515,9 +524,9 @@ void MidiAlsaSeq::run()
"ALSA-sequencer: unhandled input "
"event %d\n", ev->type );
break;
}
} // end switch
} while( snd_seq_event_input_pending( m_seqHandle, 0 ) > 0 );
} // end while
}