JACK emits on_backend_shutdown event

README.md

@@ -237,6 +237,7 @@ view `coverage/index.html` in a browser.
  0. Ability to parse PulseAudio's "front-left" "front-right" channel label strings
  0. When two soundio clients are talking to each other, use port names to
     negotiate channel maps.
+ 0. JACK: implement prebuffering
  0. why does pulseaudio microphone use up all the CPU?
  0. merge in/out stream structures and functions?
  0. implement CoreAudio (OSX) backend, get examples working
@@ -248,7 +249,11 @@ view `coverage/index.html` in a browser.
     the microphone example.
  0. PulseAudio: when prebuf gets set to 0 need to pass `PA_STREAM_START_CORKED`.
  0. In ALSA do we need to wake up the poll when destroying the in or out stream?
- 0. Create a test for clearing the playback buffer.
+ 0. Verify that JACK xrun callback context is the same as process callback.
+    If not, might need to hav xrun callback set a flag and have process callback
+    call the underflow callback.
+ 0. Detect PulseAudio server going offline and emit `on_backend_disconnect`.
+ 0. Create a test for clearing the playback buffer and prebuffering.
  0. Create a test for pausing and resuming input and output streams.
  0. Create a test for the latency / synchronization API.
     - Input is an audio file and some events indexed at particular frame - when

src/jack.cpp

@@ -35,7 +35,8 @@ static void flush_events_jack(struct SoundIoPrivate *si) {
     SoundIo *soundio = &si->pub;
     SoundIoJack *sij = &si->backend_data.jack;
 
-    bool change = false;
+    bool change_devices = false;
+    bool cb_shutdown = false;
     SoundIoDevicesInfo *old_devices_info = nullptr;
 
     soundio_os_mutex_lock(sij->mutex);
@@ -44,15 +45,22 @@ static void flush_events_jack(struct SoundIoPrivate *si) {
         old_devices_info = si->safe_devices_info;
         si->safe_devices_info = sij->ready_devices_info;
         sij->ready_devices_info = nullptr;
-        change = true;
+        change_devices = true;
+    }
+
+    if (sij->is_shutdown && !sij->emitted_shutdown_cb) {
+        sij->emitted_shutdown_cb = true;
+        cb_shutdown = true;
     }
 
     soundio_os_mutex_unlock(sij->mutex);
 
-    if (change)
+    if (change_devices)
         soundio->on_devices_change(soundio);
-
     soundio_destroy_devices_info(old_devices_info);
+
+    if (cb_shutdown)
+        soundio->on_backend_disconnect(soundio);
 }
 
 static void wait_events_jack(struct SoundIoPrivate *si) {
@@ -96,17 +104,58 @@ static SoundIoDeviceJackPort *find_port_matching_channel(SoundIoDevice *device,
     return nullptr;
 }
 
+static int outstream_xrun_callback(void *arg) {
+    SoundIoOutStreamPrivate *os = (SoundIoOutStreamPrivate *)arg;
+    SoundIoOutStream *outstream = &os->pub;
+    outstream->underflow_callback(outstream);
+    return 0;
+}
+
+static int outstream_buffer_size_callback(jack_nframes_t nframes, void *arg) {
+    SoundIoOutStreamPrivate *os = (SoundIoOutStreamPrivate *)arg;
+    SoundIoOutStream *outstream = &os->pub;
+    SoundIo *soundio = outstream->device->soundio;
+    SoundIoPrivate *si = (SoundIoPrivate *)soundio;
+    SoundIoJack *sij = &si->backend_data.jack;
+    if ((jack_nframes_t)sij->buffer_size == nframes) {
+        return 0;
+    } else {
+        outstream->error_callback(outstream, SoundIoErrorStreaming);
+        return -1;
+    }
+}
+
+static int outstream_sample_rate_callback(jack_nframes_t nframes, void *arg) {
+    SoundIoOutStreamPrivate *os = (SoundIoOutStreamPrivate *)arg;
+    SoundIoOutStream *outstream = &os->pub;
+    if (nframes == (jack_nframes_t)outstream->sample_rate) {
+        return 0;
+    } else {
+        outstream->error_callback(outstream, SoundIoErrorStreaming);
+        return -1;
+    }
+}
+
+static void outstream_shutdown_callback(void *arg) {
+    SoundIoOutStreamPrivate *os = (SoundIoOutStreamPrivate *)arg;
+    SoundIoOutStream *outstream = &os->pub;
+    outstream->error_callback(outstream, SoundIoErrorStreaming);
+}
+
 static int outstream_open_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os) {
+    SoundIoJack *sij = &si->backend_data.jack;
     SoundIoOutStreamJack *osj = &os->backend_data.jack;
     SoundIoOutStream *outstream = &os->pub;
     SoundIoDevice *device = outstream->device;
     SoundIoDevicePrivate *dev = (SoundIoDevicePrivate *)device;
     SoundIoDeviceJack *dj = &dev->backend_data.jack;
 
+    if (sij->is_shutdown)
+        return SoundIoErrorBackendDisconnected;
 
-    outstream->buffer_duration = 0.0; // TODO
-    outstream->period_duration = 0.0; // TODO
-    outstream->prebuf_duration = 0.0; // TODO
+    outstream->buffer_duration = device->buffer_duration_current;
+    outstream->period_duration = 0.0;
+    outstream->prebuf_duration = 0.0;
 
     jack_status_t status;
     osj->client = jack_client_open(outstream->name, JackNoStartServer, &status);
@@ -125,7 +174,19 @@ static int outstream_open_jack(struct SoundIoPrivate *si, struct SoundIoOutStrea
         outstream_destroy_jack(si, os);
         return SoundIoErrorOpeningDevice;
     }
-    // TODO register the other callbacks and emit a stream error if they're called
+    if ((err = jack_set_buffer_size_callback(osj->client, outstream_buffer_size_callback, os))) {
+        outstream_destroy_jack(si, os);
+        return SoundIoErrorOpeningDevice;
+    }
+    if ((err = jack_set_sample_rate_callback(osj->client, outstream_sample_rate_callback, os))) {
+        outstream_destroy_jack(si, os);
+        return SoundIoErrorOpeningDevice;
+    }
+    if ((err = jack_set_xrun_callback(osj->client, outstream_xrun_callback, os))) {
+        outstream_destroy_jack(si, os);
+        return SoundIoErrorOpeningDevice;
+    }
+    jack_on_shutdown(osj->client, outstream_shutdown_callback, os);
 
 
     // register ports and map channels
@@ -171,9 +232,10 @@ static int outstream_open_jack(struct SoundIoPrivate *si, struct SoundIoOutStrea
 static int outstream_pause_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os, bool pause) {
     SoundIoOutStreamJack *osj = &os->backend_data.jack;
     SoundIoOutStream *outstream = &os->pub;
-    // TODO SoundIoDevice *device = outstream->device;
-    // TODO SoundIoDevicePrivate *dev = (SoundIoDevicePrivate *)device;
-    // TODO SoundIoDeviceJack *dj = &dev->backend_data.jack;
+    SoundIoJack *sij = &si->backend_data.jack;
+    if (sij->is_shutdown)
+        return SoundIoErrorBackendDisconnected;
+
     int err;
     if (pause) {
         if ((err = jack_deactivate(osj->client)))
@@ -227,35 +289,50 @@ static int outstream_end_write_jack(struct SoundIoPrivate *, struct SoundIoOutSt
 }
 
 static int outstream_clear_buffer_jack(struct SoundIoPrivate *, struct SoundIoOutStreamPrivate *) {
-    soundio_panic("TODO clear buffer");
+    // JACK does not support `prebuf` which is the same as a `prebuf` value of 0,
+    // which means that clearing the buffer is always successful and does nothing.
+    return 0;
 }
 
 
 
-
-static int instream_open_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *) {
-    soundio_panic("TODO open instream");
-}
-
 static void instream_destroy_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *) {
     soundio_panic("TODO destroy instream");
 }
 
-static int instream_start_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *) {
+static int instream_open_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
+    //SoundIoInStream *outstream = &is->pub;
+    //SoundIoInStreamJack *isj = &is->backend_data.jack;
+    SoundIoJack *sij = &si->backend_data.jack;
+    if (sij->is_shutdown) {
+        instream_destroy_jack(si, is);
+        return SoundIoErrorBackendDisconnected;
+    }
+    soundio_panic("TODO open instream");
+}
+
+static int instream_start_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
+    SoundIoJack *sij = &si->backend_data.jack;
+    if (sij->is_shutdown)
+        return SoundIoErrorBackendDisconnected;
+
     soundio_panic("TODO start instream");
 }
 
-static int instream_begin_read_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *,
+static int instream_begin_read_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is,
         SoundIoChannelArea **out_areas, int *frame_count)
 {
     soundio_panic("TODO begin read");
 }
 
-static int instream_end_read_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *) {
+static int instream_end_read_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
     soundio_panic("TODO end read");
 }
 
-static int instream_pause_jack(struct SoundIoPrivate *, struct SoundIoInStreamPrivate *, bool pause) {
+static int instream_pause_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is, bool pause) {
+    SoundIoJack *sij = &si->backend_data.jack;
+    if (sij->is_shutdown)
+        return SoundIoErrorBackendDisconnected;
     soundio_panic("TODO pause");
 }
 
@@ -326,6 +403,10 @@ static int refresh_devices(SoundIoPrivate *si) {
     SoundIo *soundio = &si->pub;
     SoundIoJack *sij = &si->backend_data.jack;
 
+    if (sij->is_shutdown)
+        return SoundIoErrorBackendDisconnected;
+
+
     SoundIoDevicesInfo *devices_info = create<SoundIoDevicesInfo>();
     if (!devices_info)
         return SoundIoErrorNoMem;
@@ -513,12 +594,6 @@ static int refresh_devices(SoundIoPrivate *si) {
     return 0;
 }
 
-static int process_callback(jack_nframes_t nframes, void *arg) {
-    ////SoundIoPrivate *si = (SoundIoPrivate *)arg;
-    //soundio_panic("TODO process callback");
-    return 0;
-}
-
 static int buffer_size_callback(jack_nframes_t nframes, void *arg) {
     SoundIoPrivate *si = (SoundIoPrivate *)arg;
     SoundIoJack *sij = &si->backend_data.jack;
@@ -537,12 +612,6 @@ static int sample_rate_callback(jack_nframes_t nframes, void *arg) {
     return 0;
 }
 
-/* TODO
-static int xrun_callback(void *arg) {
-    return 0;
-}
-*/
-
 static void port_registration_callback(jack_port_id_t port_id, int reg, void *arg) {
     SoundIoPrivate *si = (SoundIoPrivate *)arg;
     SoundIoJack *sij = &si->backend_data.jack;
@@ -561,8 +630,13 @@ static int port_rename_calllback(jack_port_id_t port_id,
 }
 
 static void shutdown_callback(void *arg) {
-    //SoundIoPrivate *si = (SoundIoPrivate *)arg;
-    soundio_panic("TODO shutdown callback");
+    SoundIoPrivate *si = (SoundIoPrivate *)arg;
+    SoundIo *soundio = &si->pub;
+    SoundIoJack *sij = &si->backend_data.jack;
+    soundio_os_mutex_lock(sij->mutex);
+    sij->is_shutdown = true;
+    soundio->on_events_signal(soundio);
+    soundio_os_mutex_unlock(sij->mutex);
 }
 
 static void destroy_jack(SoundIoPrivate *si) {
@@ -620,10 +694,6 @@ int soundio_jack_init(struct SoundIoPrivate *si) {
     }
 
     int err;
-    if ((err = jack_set_process_callback(sij->client, process_callback, si))) {
-        destroy_jack(si);
-        return SoundIoErrorInitAudioBackend;
-    }
     if ((err = jack_set_buffer_size_callback(sij->client, buffer_size_callback, si))) {
         destroy_jack(si);
         return SoundIoErrorInitAudioBackend;
@@ -632,12 +702,6 @@ int soundio_jack_init(struct SoundIoPrivate *si) {
         destroy_jack(si);
         return SoundIoErrorInitAudioBackend;
     }
-    /* TODO
-    if ((err = jack_set_xrun_callback(sij->client, xrun_callback, si))) {
-        destroy_jack(si);
-        return SoundIoErrorInitAudioBackend;
-    }
-    */
     if ((err = jack_set_port_registration_callback(sij->client, port_registration_callback, si))) {
         destroy_jack(si);
         return SoundIoErrorInitAudioBackend;
@@ -648,6 +712,9 @@ int soundio_jack_init(struct SoundIoPrivate *si) {
     }
     jack_on_shutdown(sij->client, shutdown_callback, si);
 
+    sij->buffer_size = jack_get_buffer_size(sij->client);
+    sij->sample_rate = jack_get_sample_rate(sij->client);
+
     if ((err = jack_activate(sij->client))) {
         destroy_jack(si);
         return SoundIoErrorInitAudioBackend;

src/jack.hpp

@@ -35,6 +35,8 @@ struct SoundIoJack {
     bool initialized;
     int sample_rate;
     int buffer_size;
+    bool is_shutdown;
+    bool emitted_shutdown_cb;
 };
 
 struct SoundIoOutStreamJackPort {

src/soundio.cpp

@@ -59,6 +59,7 @@ const char *soundio_strerror(int error) {
         case SoundIoErrorIncompatibleDevice: return "incompatible device";
         case SoundIoErrorNoSuchClient: return "no such client";
         case SoundIoErrorIncompatibleBackend: return "incompatible backend";
+        case SoundIoErrorBackendDisconnected: return "backend disconnected";
     }
     soundio_panic("invalid error enum value: %d", error);
 }
@@ -139,8 +140,7 @@ void soundio_destroy(struct SoundIo *soundio) {
     destroy(si);
 }
 
-static void default_on_devices_change(struct SoundIo *) { }
-static void default_on_events_signal(struct SoundIo *) { }
+static void do_nothing_cb(struct SoundIo *) { }
 static void default_msg_callback(const char *msg) { }
 
 struct SoundIo * soundio_create(void) {
@@ -149,8 +149,9 @@ struct SoundIo * soundio_create(void) {
     if (!si)
         return NULL;
     SoundIo *soundio = &si->pub;
-    soundio->on_devices_change = default_on_devices_change;
-    soundio->on_events_signal = default_on_events_signal;
+    soundio->on_devices_change = do_nothing_cb;
+    soundio->on_backend_disconnect = do_nothing_cb;
+    soundio->on_events_signal = do_nothing_cb;
     soundio->app_name = "SoundIo";
     soundio->jack_info_callback = default_msg_callback;
     soundio->jack_error_callback = default_msg_callback;

src/soundio.h

@@ -28,6 +28,7 @@ enum SoundIoError {
     SoundIoErrorIncompatibleDevice,
     SoundIoErrorNoSuchClient,
     SoundIoErrorIncompatibleBackend,
+    SoundIoErrorBackendDisconnected,
 };
 
 enum SoundIoChannelId {
@@ -203,6 +204,12 @@ struct SoundIo {
     // Optional callback. Called when the list of devices change. Only called
     // during a call to soundio_flush_events or soundio_wait_events.
     void (*on_devices_change)(struct SoundIo *);
+    // Optional callback. Called when the backend disconnects. For example,
+    // when the JACK server shuts down. When this happens, listing devices
+    // and opening streams will always fail with
+    // SoundIoErrorBackendDisconnected. This callback is only called during a
+    // call to soundio_flush_events or soundio_wait_events.
+    void (*on_backend_disconnect)(struct SoundIo *);
     // Optional callback. Called from an unknown thread that you should not use
     // to call any soundio functions. You may use this to signal a condition
     // variable to wake up. Called when soundio_wait_events would be woken up.
@@ -349,6 +356,9 @@ struct SoundIoOutStream {
     // How many seconds need to be in the buffer before playback will commence.
     // If a buffer underflow occurs, this prebuffering will be again enabled.
     // This value defaults to being the same as `buffer_duration`.
+    // After you call `soundio_outstream_open` this value is replaced with the
+    // actual `prebuf_duration`, as near to this value as possible.
+    // JACK does not support prebuffering; `prebuf_duration` is effectively 0.
     double prebuf_duration;
 
     // Defaults to NULL. Put whatever you want here.