Avoid crash on gui when rendering from command line and no write acce…

…ss (#3322)

src/core/audio/AudioFileDevice.cpp

@@ -27,6 +27,7 @@
 
 #include "AudioFileDevice.h"
 #include "ExportProjectDialog.h"
+#include "GuiApplication.h"
 
 
 AudioFileDevice::AudioFileDevice( const sample_rate_t _sample_rate,
@@ -50,17 +51,27 @@ AudioFileDevice::AudioFileDevice( const sample_rate_t _sample_rate,
 
  if( m_outputFile.open( QFile::WriteOnly | QFile::Truncate ) == false )
  {
- QMessageBox::critical( NULL,
-  ExportProjectDialog::tr( "Could not open file" ),
-  ExportProjectDialog::tr( "Could not open file %1 "
+ QString title, message;
+ title = ExportProjectDialog::tr( "Could not open file" );
+ message = ExportProjectDialog::tr( "Could not open file %1 "
  "for writing.\nPlease make "
- "sure you have write-"
+ "sure you have write "
  "permission to the file and "
  "the directory containing the "
- "file and try again!" ).arg(
- _file ),
- QMessageBox::Ok,
- QMessageBox::NoButton );
+ "file and try again!"
+ ).arg( _file );
+
+ if( gui )
+ {
+ QMessageBox::critical( NULL, title, message,
+ QMessageBox::Ok,
+ QMessageBox::NoButton );
+ }
+ else
+ {
+ fprintf( stderr, "%s\n", message.toUtf8().constData() );
+ exit( EXIT_FAILURE );
+ }
  }
 }