PulseAudio: detect server going offline

README.md

@@ -272,10 +272,10 @@ Then look at `html/index.html` in a browser.
 
 ## Roadmap
 
- 0. Detect PulseAudio server going offline and emit `on_backend_disconnect`.
  0. Ability to "activate" a buffer-flexible outstream by jumping the gun and
     causing `write_callback` to be called early.
     - Use the same mechanism when destroying the outstream
+ 0. Create a test for recovering from backend disconnecting that reconnects
  0. Create a test for input stream overflow handling.
  0. Create a test for the latency / synchronization API.
     - Input is an audio file and some events indexed at particular frame - when

src/pulseaudio.cpp

@@ -36,6 +36,7 @@ static int subscribe_to_events(SoundIoPrivate *si) {
 static void context_state_callback(pa_context *context, void *userdata) {
     SoundIoPrivate *si = (SoundIoPrivate *)userdata;
     SoundIoPulseAudio *sipa = &si->backend_data.pulseaudio;
+    SoundIo *soundio = &si->pub;
 
     switch (pa_context_get_state(context)) {
     case PA_CONTEXT_UNCONNECTED: // The context hasn't been connected yet.
@@ -55,7 +56,9 @@ static void context_state_callback(pa_context *context, void *userdata) {
         return;
     case PA_CONTEXT_FAILED: // The connection failed or was disconnected.
         sipa->connection_err = SoundIoErrorInitAudioBackend;
-        sipa->ready_flag = true;
+        if (sipa->ready_flag.exchange(true)) {
+            soundio->on_backend_disconnect(soundio, SoundIoErrorBackendDisconnected);
+        }
         pa_threaded_mainloop_signal(sipa->main_loop, 0);
         return;
     }