Merge branch 'master' of https://github.com/hydrogen-music/hydrogen

src/core/src/IO/disk_writer_driver.cpp

@@ -226,6 +226,9 @@ void* diskWriterDriver_thread( void* param )
 			//pDriver->m_transport.m_nFrames = frameNumber;
 
 			int ret = pDriver->m_processCallback( usedBuffer, nullptr );
+			while( ret != 0) {
+				ret = pDriver->m_processCallback( usedBuffer, nullptr );
+			}
 
 			for ( unsigned i = 0; i < usedBuffer; i++ ) {
 				if(pData_L[i] > 1){

src/core/src/hydrogen.cpp

@@ -464,6 +464,7 @@ static void			audioEngine_noteOn( Note *note );
    latter will be set to @a nframes.
  * \param arg Unused.
  * \return
+ * - __2__ : Failed to aquire the audio engine lock, no processing took place.
  * - __1__ : kill the audio driver thread. This will be used if either
  * the DiskWriterDriver or FakeDriver are used and the end of the Song
  * is reached (audioEngine_updateNoteQueue() returned -1 ). 
@@ -1268,9 +1269,14 @@ int audioEngine_process( uint32_t nframes, void* /*arg*/ )
 	 * The "try_lock" was introduced for Bug #164 (Deadlock after during
 	 * alsa driver shutdown). The try_lock *should* only fail in rare circumstances
 	 * (like shutting down drivers). In such cases, it seems to be ok to interrupt
-	 * audio processing.
+	 * audio processing. Returning the special return value "2" enables the disk 
+	 * writer driver to repeat the processing of the current data.
 	 */
-	if(!AudioEngine::get_instance()->try_lock( RIGHT_HERE )){
+	if(!AudioEngine::get_instance()->try_lock( RIGHT_HERE )) {
+		if ( m_pAudioDriver->class_name() == DiskWriterDriver::class_name() ) {
+			return 2;	// inform the caller that we could not aquire the lock
+		}
+
 		return 0;
 	}
 

src/gui/src/PatternEditor/PatternEditorRuler.cpp

@@ -118,6 +118,13 @@ void PatternEditorRuler::updateEditor( bool bRedrawAll )
 	static int oldNTicks = 0;
 
 	Hydrogen *pEngine = Hydrogen::get_instance();
+
+	//Do not redraw anything if Export is active.
+	//https://github.com/hydrogen-music/hydrogen/issues/857	
+	if( pEngine->getIsExportSessionActive() ) {
+		return;
+	}
+
 	PatternList *pPatternList = pEngine->getSong()->get_pattern_list();
 	int nSelectedPatternNumber = pEngine->getSelectedPatternNumber();
 	if ( (nSelectedPatternNumber != -1) && ( (uint)nSelectedPatternNumber < pPatternList->size() )  ) {

src/gui/src/SongEditor/SongEditor.cpp

@@ -1153,6 +1153,13 @@ void SongEditorPatternList::createBackground()
 	boldTextFont.setBold( true );
 
 	Hydrogen *pEngine = Hydrogen::get_instance();
+
+	//Do not redraw anything if Export is active.
+	//https://github.com/hydrogen-music/hydrogen/issues/857	
+	if( pEngine->getIsExportSessionActive() ) {
+		return;
+	}
+
 	Song *pSong = pEngine->getSong();
 	int nPatterns = pSong->get_pattern_list()->size();
 	int nSelectedPattern = pEngine->getSelectedPatternNumber();