Add functionality to show ASIO control panel

libs/backends/portaudio/portaudio_backend.cc

@@ -376,6 +376,18 @@ PortAudioBackend::systemic_output_latency () const
 	return _systemic_audio_output_latency;
 }
 
+std::string
+PortAudioBackend::control_app_name () const
+{
+	return _pcmio->control_app_name (name_to_id (_input_audio_device));
+}
+
+void
+PortAudioBackend::launch_control_app ()
+{
+	return _pcmio->launch_control_app (name_to_id(_input_audio_device));
+}
+
 /* MIDI */
 
 std::vector<std::string>

libs/backends/portaudio/portaudio_backend.h

@@ -212,8 +212,8 @@ class PortAudioBackend : public AudioBackend {
 		bool can_set_systemic_midi_latencies () const { return false; }
 
 		/* External control app */
-		std::string control_app_name () const { return std::string (); }
+		std::string control_app_name () const;
-		void launch_control_app () {}
+		void launch_control_app ();
 
 		/* MIDI */
 		std::vector<std::string> enumerate_midi_options () const;

libs/backends/portaudio/portaudio_io.cc

@@ -24,6 +24,10 @@
 #include <glibmm.h>
 #include "portaudio_io.h"
 
+#ifdef WITH_ASIO
+#include "pa_asio.h"
+#endif
+
 #include "pbd/compose.h"
 
 #include "debug.h"
@@ -63,6 +67,43 @@ PortAudioIO::~PortAudioIO ()
 	free (_output_buffer); _output_buffer = NULL;
 }
 
+std::string
+PortAudioIO::control_app_name (int device_id) const
+{
+	const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
+	std::string app_name;
+
+	if (info == NULL) {
+		DEBUG_AUDIO (string_compose ("Unable to determine Host API from index %1\n",
+		                             _host_api_index));
+		return app_name;
+	}
+
+	PaHostApiTypeId type_id = info->type;
+
+#ifdef WITH_ASIO
+	if (type_id == paASIO) {
+		// is this used for anything, or just acts as a boolean?
+		return "PortaudioASIO";
+	}
+#endif
+
+	return app_name;
+}
+
+void
+PortAudioIO::launch_control_app (int device_id)
+{
+#ifdef WITH_ASIO
+	PaError err = PaAsio_ShowControlPanel (device_id, NULL);
+
+	if (err != paNoError) {
+		// error << ?
+		DEBUG_AUDIO (string_compose (
+		    "Unable to show control panel for device with index %1\n", device_id));
+	}
+#endif
+}
 
 int
 PortAudioIO::available_sample_rates(int device_id, std::vector<float>& sampleRates)
@@ -209,8 +250,10 @@ PortAudioIO::get_host_api_index_from_name (const std::string& name)
 
 	for (int i = 0; i < count; ++i) {
 		const PaHostApiInfo* info = Pa_GetHostApiInfo (i);
-		if (info->name != NULL) { // possible?
+		if (info != NULL && info->name != NULL) { // possible?
-			if (name == info->name) return i;
+			if (name == info->name) {
+				return i;
+			}
 		}
 	}
 	DEBUG_AUDIO (string_compose ("Unable to get host API from name: %1\n", name));

libs/backends/portaudio/portaudio_io.h

@@ -54,6 +54,8 @@ public:
 	int      available_sample_rates (int device_id, std::vector<float>& sampleRates);
 	int      available_buffer_sizes (int device_id, std::vector<uint32_t>& sampleRates);
 
+	std::string control_app_name (int device_id) const;
+	void launch_control_app (int device_id);
 
 	void     pcm_stop (void);
 	int      pcm_start (void);

libs/backends/portaudio/wscript

@@ -17,6 +17,7 @@ def options(opt):
 def configure(conf):
     autowaf.configure(conf)
     autowaf.check_pkg(conf, 'portaudio-2.0', uselib_store='PORTAUDIO', atleast_version='19')
+    conf.check(header_name='pa_asio.h', define_name='WITH_ASIO', mandatory=False)
 
 def build(bld):
     obj = bld(features = 'cxx cxxshlib')