Replace every use of the foreach macro with a C++11 range-based for loop

This prevents a race condition with Qt5. A foreach loop makes a copy of its
Qt container, increasing the reference count to the container's internal
data. Qt5 often asserts isDetached(), which requires the reference count to
be <= 1. This assertion fails when the foreach loop increases the reference
count at exactly the wrong moment. Using a range-based for loop prevents an
unnecessary copy from being made and ensures this race condition isn't
triggered.

include/InstrumentPlayHandle.h

@@ -56,13 +56,13 @@ public:
 		do
 		{
 			nphsLeft = false;
-			foreach( const NotePlayHandle * cnph, nphv )
+			for( const NotePlayHandle * constNotePlayHandle : nphv )
 			{
-				NotePlayHandle * nph = const_cast<NotePlayHandle *>( cnph );
-				if( nph->state() != ThreadableJob::Done && ! nph->isFinished() )
+				NotePlayHandle * notePlayHandle = const_cast<NotePlayHandle *>( constNotePlayHandle );
+				if( notePlayHandle->state() != ThreadableJob::Done && ! notePlayHandle->isFinished() )
 				{
 					nphsLeft = true;
-					nph->process();
+					notePlayHandle->process();
 				}
 			}
 		}

plugins/MidiExport/MidiExport.cpp

@@ -83,7 +83,7 @@ bool MidiExport::tryExport( const TrackContainer::TrackList &tracks, int tempo,
 	uint8_t buffer[BUFFER_SIZE];
 	uint32_t size;
 
-	foreach( Track* track, tracks ) if( track->type() == Track::InstrumentTrack ) nTracks++;
+	for( const Track* track : tracks ) if( track->type() == Track::InstrumentTrack ) nTracks++;
 
 	// midi header
 	MidiFile::MIDIHeader header(nTracks);
@@ -91,7 +91,7 @@ bool MidiExport::tryExport( const TrackContainer::TrackList &tracks, int tempo,
 	midiout.writeRawData((char *)buffer, size);
 
 	// midi tracks
-	foreach( Track* track, tracks )
+	for( Track* track : tracks )
 	{
 		DataFile dataFile( DataFile::SongProject );
 		MidiFile::MIDITrack<BUFFER_SIZE> mtrack;

plugins/zynaddsubfx/ZynAddSubFx.cpp

@@ -262,7 +262,7 @@ void ZynAddSubFxInstrument::loadSettings( const QDomElement & _this )
 		m_pluginMutex.unlock();
 
 		m_modifiedControllers.clear();
-		foreach( const QString & c, _this.attribute( "modifiedcontrollers" ).split( ',' ) )
+		for( const QString & c : _this.attribute( "modifiedcontrollers" ).split( ',' ) )
 		{
 			if( !c.isEmpty() )
 			{

src/core/AutomatableModel.cpp

@@ -450,7 +450,7 @@ void AutomatableModel::unlinkModels( AutomatableModel* model1, AutomatableModel*
 
 void AutomatableModel::unlinkAllModels()
 {
-	foreach( AutomatableModel* model, m_linkedModels )
+	for( AutomatableModel* model : m_linkedModels )
 	{
 		unlinkModels( this, model );
 	}

src/core/ComboBoxModel.cpp

@@ -39,7 +39,7 @@ void ComboBoxModel::addItem( const QString& item, PixmapLoader* loader )
 void ComboBoxModel::clear()
 {
 	setRange( 0, 0 );
-	foreach( const Item& i, m_items )
+	for( const Item& i : m_items )
 	{
 		delete i.second;
 	}

src/core/FxMixer.cpp

@@ -87,7 +87,7 @@ FxChannel::~FxChannel()
 
 inline void FxChannel::processed()
 {
-	foreach( FxRoute * receiverRoute, m_sends )
+	for( const FxRoute * receiverRoute : m_sends )
 	{
 		if( receiverRoute->receiver()->m_muted == false )
 		{
@@ -121,7 +121,7 @@ void FxChannel::doProcessing()
 
 	if( m_muted == false )
 	{
-		foreach( FxRoute * senderRoute, m_receives )
+		for( FxRoute * senderRoute : m_receives )
 		{
 			FxChannel * sender = senderRoute->sender();
 			FloatModel * sendModel = senderRoute->amount();
@@ -293,7 +293,7 @@ void FxMixer::deleteChannel( int index )
 	tracks += Engine::getSong()->tracks();
 	tracks += Engine::getBBTrackContainer()->tracks();
 
-	foreach( Track* t, tracks )
+	for( Track* t : tracks )
 	{
 		if( t->type() == Track::InstrumentTrack )
 		{
@@ -335,11 +335,11 @@ void FxMixer::deleteChannel( int index )
 		m_fxChannels[i]->m_channelIndex = i;
 
 		// now check all routes and update names of the send models
-		foreach( FxRoute * r, m_fxChannels[i]->m_sends )
+		for( FxRoute * r : m_fxChannels[i]->m_sends )
 		{
 			r->updateName();
 		}
-		foreach( FxRoute * r, m_fxChannels[i]->m_receives )
+		for( FxRoute * r : m_fxChannels[i]->m_receives )
 		{
 			r->updateName();
 		}
@@ -528,7 +528,7 @@ FloatModel * FxMixer::channelSendModel( fx_ch_t fromChannel, fx_ch_t toChannel )
 	const FxChannel * from = m_fxChannels[fromChannel];
 	const FxChannel * to = m_fxChannels[toChannel];
 
-	foreach( FxRoute * route, from->m_sends )
+	for( FxRoute * route : from->m_sends )
 	{
 		if( route->receiver() == to )
 		{
@@ -578,7 +578,7 @@ void FxMixer::masterMix( sampleFrame * _buf )
 		// also instantly add all muted channels as they don't need to care about their senders, and can just increment the deps of
 		// their recipients right away.
 		MixerWorkerThread::resetJobQueue( MixerWorkerThread::JobQueue::Dynamic );
-		foreach( FxChannel * ch, m_fxChannels )
+		for( FxChannel * ch : m_fxChannels )
 		{
 			ch->m_muted = ch->m_muteModel.value();
 			if( ch->m_muted ) // instantly "process" muted channels

src/core/NotePlayHandle.cpp

@@ -301,17 +301,6 @@ void NotePlayHandle::play( sampleFrame * _working_buffer )
 		}
 	}
 
-	// play sub-notes (e.g. chords)
-	// handled by mixer now
-/*	foreach( NotePlayHandle * n, m_subNotes )
-	{
-		n->play( _working_buffer );
-		if( n->isFinished() )
-		{
-			NotePlayHandleManager::release( n );
-		}
-	}*/
-
 	// update internal data
 	m_totalFramesPlayed += framesThisPeriod;
 	unlock();
@@ -369,7 +358,7 @@ void NotePlayHandle::noteOff( const f_cnt_t _s )
 	m_released = true;
 
 	// first note-off all sub-notes
-	foreach( NotePlayHandle * n, m_subNotes )
+	for( NotePlayHandle * n : m_subNotes )
 	{
 		n->lock();
 		n->noteOff( _s );

src/core/audio/AudioPort.cpp

@@ -116,7 +116,7 @@ void AudioPort::doProcessing()
 	BufferManager::clear( m_portBuffer, fpp );
 
 	//qDebug( "Playhandles: %d", m_playHandles.size() );
-	foreach( PlayHandle * ph, m_playHandles ) // now we mix all playhandle buffers into the audioport buffer
+	for( PlayHandle * ph : m_playHandles ) // now we mix all playhandle buffers into the audioport buffer
 	{
 		if( ph->buffer() )
 		{

src/core/fft_helpers.cpp

@@ -134,7 +134,7 @@ int compressbands(float *absspec_buffer, float *compressedband, int num_old, int
 
 	ratio=(float)usefromold/(float)num_new;
 
-	// foreach new subband
+	// for each new subband
 	for ( i=0; i<num_new; i++ )
 	{
 		compressedband[i]=0;

src/gui/EffectSelectDialog.cpp

@@ -216,7 +216,7 @@ void EffectSelectDialog::rowChanged( const QModelIndex & _idx,
             subLayout->setSpacing( 0 );
             m_currentSelection.desc->subPluginFeatures->
                 fillDescriptionWidget( subWidget, &m_currentSelection );
-            foreach( QWidget * w, subWidget->findChildren<QWidget *>() )
+            for( QWidget * w : subWidget->findChildren<QWidget *>() )
             {
                 if( w->parent() == subWidget )
                 {

src/gui/FxMixerView.cpp

@@ -420,7 +420,7 @@ void FxMixerView::deleteUnusedChannels()
 	{
 		// check if an instrument references to the current channel
 		bool empty=true;
-		foreach( Track* t, tracks )
+		for( Track* t : tracks )
 		{
 			if( t->type() == Track::InstrumentTrack )
 			{

src/gui/MainWindow.cpp

@@ -145,7 +145,7 @@ MainWindow::MainWindow() :
 
 #if ! defined(LMMS_BUILD_APPLE)
 	QFileInfoList drives = QDir::drives();
-	foreach( const QFileInfo & drive, drives )
+	for( const QFileInfo & drive : drives )
 	{
 		root_paths += drive.absolutePath();
 	}
@@ -602,7 +602,7 @@ void MainWindow::finalize()
 	gui->songEditor()->parentWidget()->show();
 
 	// reset window title every time we change the state of a subwindow to show the correct title
-	foreach( QMdiSubWindow * subWindow, workspace()->subWindowList() )
+	for( const QMdiSubWindow * subWindow : workspace()->subWindowList() )
 	{
 		connect( subWindow, SIGNAL( windowStateChanged(Qt::WindowStates,Qt::WindowStates) ), this, SLOT( resetWindowTitle() ) );
 	}

src/gui/editors/BBEditor.cpp

@@ -220,7 +220,7 @@ void BBTrackContainerView::addAutomationTrack()
 
 void BBTrackContainerView::removeBBView(int bb)
 {
-	foreach( TrackView* view, trackViews() )
+	for( TrackView* view : trackViews() )
 	{
 		view->getTrackContentWidget()->removeTCOView( bb );
 	}

src/gui/widgets/AutomatableButton.cpp

@@ -236,7 +236,7 @@ void automatableButtonGroup::activateButton( AutomatableButton * _btn )
 					m_buttons.indexOf( _btn ) != -1 )
 	{
 		model()->setValue( m_buttons.indexOf( _btn ) );
-		foreach( AutomatableButton * btn, m_buttons )
+		for( AutomatableButton * btn : m_buttons )
 		{
 			btn->update();
 		}
@@ -261,7 +261,7 @@ void automatableButtonGroup::updateButtons()
 {
 	model()->setRange( 0, m_buttons.size() - 1 );
 	int i = 0;
-	foreach( AutomatableButton * btn, m_buttons )
+	for( AutomatableButton * btn : m_buttons )
 	{
 		btn->model()->setValue( i == model()->value() );
 		++i;

src/tracks/BBTrack.cpp

@@ -664,17 +664,5 @@ void BBTrackView::clickedTrackLabel()
 {
 	Engine::getBBTrackContainer()->setCurrentBB( m_bbTrack->index() );
 	gui->getBBEditor()->show();
-/*	foreach( bbTrackView * tv,
-			trackContainerView()->findChildren<bbTrackView *>() )
-	{
-		tv->m_trackLabel->update();
-	}*/
-
 }
 
-
-
-
-
-
-

src/tracks/InstrumentTrack.cpp

@@ -949,7 +949,7 @@ InstrumentTrackView::~InstrumentTrackView()
 InstrumentTrackWindow * InstrumentTrackView::topLevelInstrumentTrackWindow()
 {
 	InstrumentTrackWindow * w = NULL;
-	foreach( QMdiSubWindow * sw,
+	for( const QMdiSubWindow * sw :
 				gui->mainWindow()->workspace()->subWindowList(
 											QMdiArea::ActivationHistoryOrder ) )
 	{