[Summary] Added possibility to identify IO thread which does not have required resources initialized during process callback handling

Conflicts:
	libs/ardour/ardour/audioengine.h
	libs/backends/wavesaudio/waves_audiobackend.cc
	libs/pbd/pbd/pool.h

libs/ardour/ardour/audioengine.h

@@ -209,6 +209,9 @@ class LIBARDOUR_API AudioEngine : public SessionHandlePtr, public PortManager
 	void latency_callback (bool for_playback);
 	void halted_callback (const char* reason);
 
+	/* checks if current thread is properly set up for audio processing */
+	static bool thread_initialised_for_audio_processing ();
+
 	/* sets up the process callback thread */
 	static void thread_init_callback (void *);
 

libs/ardour/ardour/session_event.h

@@ -134,6 +134,7 @@ public:
 
 	static const framepos_t Immediate = -1;
 
+    static bool has_per_thread_pool ();
 	static void create_per_thread_pool (const std::string& n, uint32_t nitems);
 	static void init_event_pool ();
 

libs/ardour/audioengine.cc

@@ -1151,6 +1151,12 @@ AudioEngine::set_systemic_output_latency (uint32_t ol)
 	return _backend->set_systemic_output_latency  (ol);
 }
 
+bool
+AudioEngine::thread_initialised_for_audio_processing ()
+{
+    return SessionEvent::has_per_thread_pool () && AsyncMIDIPort::is_process_thread();
+}
+
 /* END OF BACKEND PROXY API */
 
 void

libs/ardour/session_events.cc

@@ -42,6 +42,12 @@ SessionEvent::init_event_pool ()
 	pool = new PerThreadPool;
 }
 
+bool
+SessionEvent::has_per_thread_pool ()
+{
+    return pool->has_per_thread_pool ();
+}
+
 void
 SessionEvent::create_per_thread_pool (const std::string& name, uint32_t nitems)
 {

libs/backends/wavesaudio/waves_audiobackend.cc

@@ -758,6 +758,17 @@ WavesAudioBackend::_audio_device_callback (const float* input_buffer,
         AudioEngine::thread_init_callback (this);
     }
 
+    if ( !engine.thread_initialised_for_audio_processing () ) {
+	    std::cerr << "\tWavesAudioBackend::_audio_device_callback (): It's an attempt to call process callback from the thread which didn't initialize it " << std::endl;
+	    
+	    if (process_id != pthread_self() ) {
+		    std::cerr << "Process thread ID has changed. Expected thread: " << process_id << " current thread: " << pthread_self() << std::dec << " !" << std::endl;
+		    process_id = pthread_self();
+	    }
+	    
+	    AudioEngine::thread_init_callback (this);
+    }
+
     engine.process_callback (nframes);
     
     _write_audio_data_to_device (output_buffer, nframes);

libs/pbd/pbd/pool.h

@@ -129,7 +129,7 @@ class LIBPBD_API PerThreadPool
 
 	void  create_per_thread_pool (std::string name, unsigned long item_size, unsigned long nitems);
 	CrossThreadPool* per_thread_pool (bool must_exist = true);
-
+	bool has_per_thread_pool ();
 	void set_trash (RingBuffer<CrossThreadPool*>* t);
 	void add_to_trash (CrossThreadPool *);
 

libs/pbd/pool.cc

@@ -175,6 +175,20 @@ PerThreadPool::create_per_thread_pool (string n, unsigned long isize, unsigned l
 	_key.set (new CrossThreadPool (n, isize, nitems, this));
 }
 
+/** @return True if CrossThreadPool for the current thread exists,
+ *  False otherwise
+ */
+bool
+PerThreadPool::has_per_thread_pool ()
+{
+    CrossThreadPool* p = _key.get();
+    if (p) {
+        return true;
+    }
+    return false;
+}
+
+
 /** @return CrossThreadPool for the current thread, which must previously have been created by
  *  calling create_per_thread_pool in the current thread.
  */