ao_pipewire: for_each_sink: properly check termination condition

Doing a pw_thread_loop_wait() without checking conditions is invalid.
The thread loop could be signalled for other reasons and in this case
the wait needs to continue.

PipeWire added such additional signaling in
commit 33be898130f0 ("thread-loop: signal when started").

This meant that for_each_sink would return before the callbacks have
fired and session_has_sink() would incorrectly return "false", failing
the initialization of ao_pipewire.

Fixes #11995

Author: t-8ch

audio/out/ao_pipewire.c

@@ -354,15 +354,21 @@ static void for_each_sink_registry_event_global(void *data, uint32_t id,
 }
 
 
+struct for_each_done_ctx {
+    struct pw_thread_loop *loop;
+    bool done;
+};
+
 static const struct pw_registry_events for_each_sink_registry_events = {
     .version = PW_VERSION_REGISTRY_EVENTS,
     .global = for_each_sink_registry_event_global,
 };
 
 static void for_each_sink_done(void *data, uint32_t it, int seq)
 {
-    struct pw_thread_loop *loop = data;
-    pw_thread_loop_signal(loop, false);
+    struct for_each_done_ctx *ctx = data;
+    ctx->done = true;
+    pw_thread_loop_signal(ctx->loop, false);
 }
 
 static const struct pw_core_events for_each_sink_core_events = {
@@ -376,12 +382,16 @@ static int for_each_sink(struct ao *ao, void (cb) (struct ao *ao, uint32_t id,
     struct priv *priv = ao->priv;
     struct pw_registry *registry;
     struct spa_hook core_listener;
+    struct for_each_done_ctx done_ctx = {
+        .loop = priv->loop,
+        .done = false,
+    };
     int ret = -1;
 
     pw_thread_loop_lock(priv->loop);
 
     spa_zero(core_listener);
-    if (pw_core_add_listener(priv->core, &core_listener, &for_each_sink_core_events, priv->loop) < 0)
+    if (pw_core_add_listener(priv->core, &core_listener, &for_each_sink_core_events, &done_ctx) < 0)
         goto unlock_loop;
 
     registry = pw_core_get_registry(priv->core, PW_VERSION_REGISTRY, 0);
@@ -400,7 +410,8 @@ static int for_each_sink(struct ao *ao, void (cb) (struct ao *ao, uint32_t id,
     if (pw_registry_add_listener(registry, &registry_listener, &for_each_sink_registry_events, &revents_ctx) < 0)
         goto destroy_registry;
 
-    pw_thread_loop_wait(priv->loop);
+    while (!done_ctx.done)
+        pw_thread_loop_wait(priv->loop);
 
     spa_hook_remove(&registry_listener);