no more crashes

src/jack-audio-module.cc

@@ -110,6 +110,8 @@ void JackAudioModule::globally_unregister() {
 }
 
 JackAudioModule::~JackAudioModule() {
+	globally_unregister();
+
 	/* and kill our port */
 	if (!g_jack_client.alive()) return;
 	for (int i = 0; i < JACK_PORTS; i++) {

src/skjack.cc

@@ -4,19 +4,17 @@
 Plugin *plugin;
 jaq::client g_jack_client;
 std::condition_variable g_jack_cv;
-
-// TODO: consider protecting this with a mutex
-// this would be optimal for correctness, but in practice this gets modified
-// very infrequently and nobody cares if we miss one or two audio frames right
-// after creating or destroying a module...
 std::mutex g_audio_modules_mutex;
 std::vector<JackAudioModule*> g_audio_modules;
 std::atomic<unsigned int> g_audio_blocked(0);
 
 int on_jack_process(jack_nframes_t nframes, void *) {
 	if (!g_jack_client.alive()) return 1;
-	/* audio modules vector is blocked; we have to skip this cycle */
-	if (!g_audio_modules_mutex.try_lock()) return 0;
+	/* JACK doesn't like us doing things that might block for a "long time."
+	 * this mutex is only locked to process audio, and add or remove modules,
+	 * and i don't think anyone is going to mind an xrun on those rare conditions
+	 */
+	std::unique_lock<std::mutex> lock(g_audio_modules_mutex);
 
 	for (auto itr = g_audio_modules.begin();
       itr != g_audio_modules.end();