refactoring to prepare for real-time export

* add a threaded TmpFile Writer
* update API calls to that process_export_fw() can be used as
  process_function

The idea is to re-use export infrastructure from normalization:
export to a tmp-file and then encode target formats after that.

3 files changed, 7 insertions, 4 deletions

diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index 7bb7aa3a4d..cb5b82d058 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -161,7 +161,7 @@ class LIBARDOUR_API AudioEngine : public PortManager, public SessionHandlePtr
 	   (the regular process() call to session->process() is not made)
 	*/
 
-	PBD::Signal1<int, pframes_t> Freewheel;
+	PBD::Signal1<void, pframes_t> Freewheel;
 
 	PBD::Signal0<void> Xrun;
 
diff --git a/libs/ardour/ardour/export_graph_builder.h b/libs/ardour/ardour/export_graph_builder.h
index df02c9eb57..68eb927513 100644
--- a/libs/ardour/ardour/export_graph_builder.h
+++ b/libs/ardour/ardour/export_graph_builder.h
@@ -41,6 +41,7 @@ namespace AudioGrapher {
 	template <typename T> class SndfileWriter;
 	template <typename T> class SilenceTrimmer;
 	template <typename T> class TmpFile;
+	template <typename T> class TmpFileRt;
 	template <typename T> class Threader;
 	template <typename T> class AllocatingProcessContext;
 }
@@ -164,6 +165,7 @@ class LIBARDOUR_API ExportGraphBuilder
 		typedef boost::shared_ptr<AudioGrapher::LoudnessReader> LoudnessReaderPtr;
 		typedef boost::shared_ptr<AudioGrapher::Normalizer> NormalizerPtr;
 		typedef boost::shared_ptr<AudioGrapher::TmpFile<Sample> > TmpFilePtr;
+		typedef boost::shared_ptr<AudioGrapher::TmpFileRt<Sample> > TmpFileRtPtr;
 		typedef boost::shared_ptr<AudioGrapher::Threader<Sample> > ThreaderPtr;
 		typedef boost::shared_ptr<AudioGrapher::AllocatingProcessContext<Sample> > BufferPtr;
 
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index c6f32bbe07..db80ddcae3 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -704,7 +704,7 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	boost::shared_ptr<ExportHandler> get_export_handler ();
 	boost::shared_ptr<ExportStatus> get_export_status ();
 
-	int start_audio_export (framepos_t position);
+	int start_audio_export (framepos_t position, bool realtime = false);
 
 	PBD::Signal1<int, framecnt_t> ProcessExport;
 	static PBD::Signal2<void,std::string, std::string> Exported;
@@ -1230,8 +1230,8 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	void process_without_events (pframes_t);
 	void process_with_events    (pframes_t);
 	void process_audition       (pframes_t);
-	int  process_export         (pframes_t);
-	int  process_export_fw      (pframes_t);
+	void process_export         (pframes_t);
+	void process_export_fw      (pframes_t);
 
 	void block_processing() { g_atomic_int_set (&processing_prohibited, 1); }
 	void unblock_processing() { g_atomic_int_set (&processing_prohibited, 0); }
@@ -1268,6 +1268,7 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 
 	bool _exporting;
 	bool _export_rolling;
+	bool _realtime_export;
 	framepos_t _export_preroll;
 	framepos_t _export_latency;