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/* This file is (c) 2018 Igor Kushnir <igorkuo@gmail.com>
* Part of GoldenDict. Licensed under GPLv3 or later, see the LICENSE file */
#include "externalaudioplayer.hh"
#include "externalviewer.hh"
ExternalAudioPlayer::ExternalAudioPlayer() : exitingViewer( 0 )
{
}
ExternalAudioPlayer::~ExternalAudioPlayer()
{
// Destroy viewers immediately to prevent memory and temporary file leaks
// at application exit.
// Set viewer to null first and foremost to make sure that onViewerDestroyed()
// doesn't attempt to start viewer or mess the smart pointer up.
stopAndDestroySynchronously( viewer.take() );
stopAndDestroySynchronously( exitingViewer );
}
void ExternalAudioPlayer::setPlayerCommandLine( QString const & playerCommandLine_ )
{
playerCommandLine = playerCommandLine_;
}
QString ExternalAudioPlayer::play( const char * data, int size )
{
stop();
Q_ASSERT( !viewer && "viewer must be null at this point for exception safety." );
try
{
// Our destructor properly destroys viewers we remember about.
// In the unlikely case that we call viewer.reset() during the application
// exit, ~QObject() prevents leaks as this class is a parent of all viewers.
viewer.reset( new ExternalViewer( data, size, "wav", playerCommandLine, this ) );
}
catch( const ExternalViewer::Ex & e )
{
return e.what();
}
if( exitingViewer )
return QString(); // Will start later.
return startViewer();
}
void ExternalAudioPlayer::stop()
{
if( !exitingViewer && viewer && !viewer->stop() )
{
// Give the previous viewer a chance to stop before starting a new one.
// This prevents overlapping audio and possible conflicts between
// external program instances.
// Graceful stopping is better than calling viewer.reset() because:
// 1) the process gets a chance to clean up and save its state;
// 2) there is no event loop blocking and consequently no (short) UI freeze
// while synchronously waiting for the external process to exit.
exitingViewer = viewer.take();
}
else // viewer is either not started or already stopped -> simply destroy it.
viewer.reset();
}
void ExternalAudioPlayer::onViewerDestroyed( QObject * destroyedViewer )
{
if( exitingViewer == destroyedViewer )
{
exitingViewer = 0;
if( viewer )
{
QString errorMessage = startViewer();
if( !errorMessage.isEmpty() )
emit error( errorMessage );
}
}
else
if( viewer.data() == destroyedViewer )
viewer.take(); // viewer finished and died -> release ownership.
}
QString ExternalAudioPlayer::startViewer()
{
Q_ASSERT( !exitingViewer && viewer );
connect( viewer.data(), &QObject::destroyed, this, &ExternalAudioPlayer::onViewerDestroyed );
try
{
viewer->start();
}
catch( const ExternalViewer::Ex & e )
{
viewer.reset();
return e.what();
}
return QString();
}
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