audio/portaudio: Add support for enumerating multiple sndio devices

sndio has no device discovery mechanism and PortAudio has no way
of accepting raw device strings from users.  Normally we just expose
the default device (which can be changed via the AUDIODEVICE
environment variable).  This however means that we are stuck with
only one device at a time for playback/recording and would have to
restart applications (or the sndiod instance) to switch between
devices.

This is detrimental to the workflow in applications like Audacity
and makes them unusable in sndio only setups.

Add a new PA_SNDIO_AUDIODEVICES environment variables with which
users can specify and expose a list of 16 additional sndio devices
to applications using PortAudio.

Example:
PA_SNDIO_AUDIODEVICES=snd/0.monitor:snd@remote/0:rsnd/3

audio/portaudio/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	portaudio
 DISTVERSION=	19_20140130
-PORTREVISION=	7
+PORTREVISION=	8
 CATEGORIES=	audio
 MASTER_SITES=	http://www.portaudio.com/archives/
 DISTNAME=	pa_stable_v${DISTVERSION}

audio/portaudio/files/pa_sndio.c

@@ -61,11 +61,20 @@ typedef struct PaSndioHostApiRepresentation
 	PaUtilStreamInterface callback;
 	PaUtilStreamInterface blocking;
 	/*
-	 * sndio has no device discovery mechanism, so expose only
+	 * sndio has no device discovery mechanism and PortAudio has
-	 * the default device, the user will have a chance to change it
+	 * no way of accepting raw device strings from users.
-	 * using the environment variable
+	 * Normally we just expose the default device, which can be
+	 * changed via the AUDIODEVICE environment variable, but we
+	 * also allow specifying a list of up to 16 devices via the
+	 * PA_SNDIO_AUDIODEVICES environment variable.
+	 *
+	 * Example:
+	 * PA_SNDIO_AUDIODEVICES=default:snd/0.monitor:snd@remote/0
 	 */
-	PaDeviceInfo *infos[1], default_info;
+#define PA_SNDIO_AUDIODEVICES_MAX	16
+	PaDeviceInfo device_info[PA_SNDIO_AUDIODEVICES_MAX];
+	PaDeviceInfo *infos[PA_SNDIO_AUDIODEVICES_MAX];
+	char *audiodevices;
 } PaSndioHostApiRepresentation;
 
 /*
@@ -248,6 +257,7 @@ OpenStream(struct PaUtilHostApiRepresentation *hostApi,
 	unsigned mode;
 	int inch, onch;
 	PaSampleFormat ifmt, ofmt, siofmt;
+	const char *dev;
 
 	DPR("OpenStream:\n");
 
@@ -257,7 +267,7 @@ OpenStream(struct PaUtilHostApiRepresentation *hostApi,
 	sio_initpar(&par);
 
 	if (outputPar && outputPar->channelCount > 0) {
-		if (outputPar->device != 0) {
+		if (outputPar->device >= sndioHostApi->base.info.deviceCount) {
 			DPR("OpenStream: %d: bad output device\n", outputPar->device);
 			return paInvalidDevice;
 		}
@@ -273,7 +283,7 @@ OpenStream(struct PaUtilHostApiRepresentation *hostApi,
 		mode |= SIO_PLAY;
 	}
 	if (inputPar && inputPar->channelCount > 0) {
-		if (inputPar->device != 0) {
+		if (inputPar->device >= sndioHostApi->base.info.deviceCount) {
 			DPR("OpenStream: %d: bad input device\n", inputPar->device);
 			return paInvalidDevice;
 		}
@@ -294,7 +304,14 @@ OpenStream(struct PaUtilHostApiRepresentation *hostApi,
 
 	DPR("OpenStream: mode = %x, trying rate = %u\n", mode, par.rate);
 
-	hdl = sio_open(SIO_DEVANY, mode, 0);
+	if (outputPar) {
+		dev = sndioHostApi->device_info[outputPar->device].name;
+	} else if (inputPar) {
+		dev = sndioHostApi->device_info[inputPar->device].name;
+	} else {
+		return paUnanticipatedHostError;
+	}
+	hdl = sio_open(dev, mode, 0);
 	if (hdl == NULL)
 		return paUnanticipatedHostError;
 	if (!sio_setpar(hdl, &par)) {
@@ -636,16 +653,37 @@ IsFormatSupported(struct PaUtilHostApiRepresentation *hostApi,
 static void
 Terminate(struct PaUtilHostApiRepresentation *hostApi)
 {
+	PaSndioHostApiRepresentation *sndioHostApi;
+	sndioHostApi = (PaSndioHostApiRepresentation *)hostApi;
+	free(sndioHostApi->audiodevices);
 	PaUtil_FreeMemory(hostApi);
 }
 
+static void
+InitDeviceInfo(PaDeviceInfo *info, PaHostApiIndex hostApiIndex, const char *name)
+{
+	info->structVersion = 2;
+	info->name = name;
+	info->hostApi = hostApiIndex;
+	info->maxInputChannels = 128;
+	info->maxOutputChannels = 128;
+	info->defaultLowInputLatency = 0.01;
+	info->defaultLowOutputLatency = 0.01;
+	info->defaultHighInputLatency = 0.5;
+	info->defaultHighOutputLatency = 0.5;
+	info->defaultSampleRate = 48000;
+}
+
 PaError
 PaSndio_Initialize(PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApiIndex)
 {
 	PaSndioHostApiRepresentation *sndioHostApi;
 	PaDeviceInfo *info;
 	struct sio_hdl *hdl;
-	
+	char *audiodevices;
+	char *device;
+	size_t deviceCount;
+
 	DPR("PaSndio_Initialize: initializing...\n");
 
 	/* unusable APIs should return paNoError and a NULL hostApi */
@@ -655,24 +693,38 @@ PaSndio_Initialize(PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApi
 	if (sndioHostApi == NULL)
 		return paNoError;
 
-	info = &sndioHostApi->default_info;
+	// Add default device
-	info->structVersion = 2;
+	info = &sndioHostApi->device_info[0];
-	info->name = "default";
+	InitDeviceInfo(info, hostApiIndex, SIO_DEVANY);
-	info->hostApi = hostApiIndex;
-	info->maxInputChannels = 128;
-	info->maxOutputChannels = 128;
-	info->defaultLowInputLatency = 0.01;
-	info->defaultLowOutputLatency = 0.01;
-	info->defaultHighInputLatency = 0.5;
-	info->defaultHighOutputLatency = 0.5;
-	info->defaultSampleRate = 48000;
 	sndioHostApi->infos[0] = info;
-	
+	deviceCount = 1;
+
+	// Add additional devices as specified in the PA_SNDIO_AUDIODEVICES
+	// environment variable as a colon separated list
+	sndioHostApi->audiodevices = NULL;
+	audiodevices = getenv("PA_SNDIO_AUDIODEVICES");
+	if (audiodevices != NULL) {
+		sndioHostApi->audiodevices = strdup(audiodevices);
+		if (sndioHostApi->audiodevices == NULL)
+			return paNoError;
+
+		audiodevices = sndioHostApi->audiodevices;
+		while ((device = strsep(&audiodevices, ":")) != NULL &&
+			deviceCount < PA_SNDIO_AUDIODEVICES_MAX) {
+			if (*device == '\0')
+				continue;
+			info = &sndioHostApi->device_info[deviceCount];
+			InitDeviceInfo(info, hostApiIndex, device);
+			sndioHostApi->infos[deviceCount] = info;
+			deviceCount++;
+		}
+	}
+
 	*hostApi = &sndioHostApi->base;
 	(*hostApi)->info.structVersion = 1;
 	(*hostApi)->info.type = paSndio;
 	(*hostApi)->info.name = "sndio";
-	(*hostApi)->info.deviceCount = 1;
+	(*hostApi)->info.deviceCount = deviceCount;
 	(*hostApi)->info.defaultInputDevice = 0;
 	(*hostApi)->info.defaultOutputDevice = 0;
 	(*hostApi)->deviceInfos = sndioHostApi->infos;