spa: bluez: a2dp-source: set media.* keys based on the device's player

Find a spa_bt_player among the devices of the transport and
set a couple media.* node properties based on the player's data.

spa/plugins/bluez5/a2dp-source.c

@@ -123,6 +123,9 @@ struct impl {
 	struct spa_bt_transport *transport;
 	struct spa_hook transport_listener;
 
+	const struct spa_bt_player *player;
+	struct spa_hook device_listener;
+
 	struct port port;
 
 	unsigned int started:1;
@@ -762,24 +765,44 @@ static int impl_node_send_command(void *object, const struct spa_command *comman
 
 static void emit_node_info(struct impl *this, bool full)
 {
-	char latency[64] = SPA_STRINGIFY(MIN_LATENCY)"/48000";
+	const uint64_t old = full ? this->info.change_mask : 0;
-	uint64_t old = full ? this->info.change_mask : 0;
-
-	struct spa_dict_item node_info_items[] = {
-		{ SPA_KEY_DEVICE_API, "bluez5" },
-		{ SPA_KEY_MEDIA_CLASS, this->is_input ? "Audio/Source" : "Stream/Output/Audio" },
-		{ SPA_KEY_NODE_LATENCY, latency },
-		{ "media.name", ((this->transport && this->transport->device->name) ?
-		                 this->transport->device->name : "A2DP") },
-                { SPA_KEY_NODE_DRIVER, this->is_input ? "true" : "false" },
-	};
 
 	if (full)
 		this->info.change_mask = this->info_all;
+
 	if (this->info.change_mask) {
+		const char * const device_name = this->transport && this->transport->device->name
+							? this->transport->device->name
+							: "A2DP";
+		const char * const artist = this->player ? this->player->track.artist : NULL;
+		const char * const title = this->player ? this->player->track.title : NULL;
+		const char * const album = this->player ? this->player->track.album : NULL;
+		const char * const software = this->player ? this->player->name : NULL;
+		char latency[64] = SPA_STRINGIFY(MIN_LATENCY) "/48000";
+		char media_name[256];
+
+		const struct spa_dict_item node_info_items[] = {
+			{ SPA_KEY_DEVICE_API, "bluez5" },
+			{ SPA_KEY_MEDIA_CLASS, this->is_input ? "Audio/Source" : "Stream/Output/Audio" },
+			{ SPA_KEY_NODE_LATENCY, latency },
+			{ SPA_KEY_NODE_DRIVER, this->is_input ? "true" : "false" },
+			{ "media.name", media_name },
+			{ "media.artist", artist },
+			{ "media.title", title },
+			{ "media.software", software },
+		};
+
+		snprintf(media_name, sizeof(media_name), "[%s] %s: %s (%s)",
+			device_name,
+			artist ? artist : "?",
+			title ? title : "?",
+			album ? album : "?"
+		);
+
 		if (this->transport && this->port.have_format)
 			snprintf(latency, sizeof(latency), "%d/%d", (int)this->props.min_latency,
 					(int)this->port.current_format.info.raw.rate);
+
 		this->info.props = &SPA_DICT_INIT_ARRAY(node_info_items);
 		spa_node_emit_info(&this->hooks, &this->info);
 		this->info.change_mask = old;
@@ -1232,6 +1255,16 @@ static const struct spa_node_methods impl_node = {
 	.process = impl_node_process,
 };
 
+static void impl_remove_hooks(struct impl *this)
+{
+	if (this->transport) {
+		spa_hook_remove(&this->transport_listener);
+
+		if (this->transport->device)
+			spa_hook_remove(&this->device_listener);
+	}
+}
+
 static int do_transport_destroy(struct spa_loop *loop,
 				bool async,
 				uint32_t seq,
@@ -1240,8 +1273,13 @@ static int do_transport_destroy(struct spa_loop *loop,
 				void *user_data)
 {
 	struct impl *this = user_data;
+
+	impl_remove_hooks(this);
+
 	this->transport = NULL;
 	this->transport_acquired = false;
+	this->player = NULL;
+
 	return 0;
 }
 
@@ -1257,6 +1295,76 @@ static const struct spa_bt_transport_events transport_events = {
         .destroy = transport_destroy,
 };
 
+static bool try_set_player(struct impl *this, const struct spa_bt_player *player)
+{
+	if (player->type != SPA_BT_PLAYER_TYPE_AUDIO && player->type != SPA_BT_PLAYER_TYPE_AUDIO_BROADCASTING)
+		return false;
+
+	spa_assert(this->transport->device == player->device);
+	this->player = player;
+
+	return true;
+}
+
+static void try_find_player(struct impl *this)
+{
+	const struct spa_bt_player *p;
+
+	if (this->transport == NULL)
+		return;
+
+	if (this->transport->device == NULL)
+		return;
+
+	spa_list_for_each(p, &this->transport->device->player_list, device_link)
+		if (try_set_player(this, p))
+			break;
+}
+
+static void player_added(void *data, struct spa_bt_player *player)
+{
+	struct impl * const this = data;
+
+	if (this->player != NULL)
+		return;
+
+	if (try_set_player(this, player))
+		emit_node_info(this, true);
+}
+
+static void player_removed(void *data, struct spa_bt_player *player)
+{
+	struct impl * const this = data;
+
+	if (this->player != player)
+		return;
+
+	this->player = NULL;
+
+	try_find_player(this);
+	emit_node_info(this, true);
+}
+
+static void player_changed(void *data, struct spa_bt_player *player)
+{
+	struct impl * const this = data;
+
+	if (this->player == NULL)
+		try_set_player(this, player);
+
+	if (this->player != player)
+		return;
+
+	emit_node_info(this, true);
+}
+
+static const struct spa_bt_device_events device_events = {
+	SPA_VERSION_BT_DEVICE_EVENTS,
+	.player_added = player_added,
+	.player_changed = player_changed,
+	.player_removed = player_removed,
+};
+
 static int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
 {
 	struct impl *this;
@@ -1277,12 +1385,15 @@ static int impl_get_interface(struct spa_handle *handle, const char *type, void
 static int impl_clear(struct spa_handle *handle)
 {
 	struct impl *this = (struct impl *) handle;
+
 	if (this->codec_data)
 		this->codec->deinit(this->codec_data);
+
 	if (this->codec_props && this->codec->clear_props)
 		this->codec->clear_props(this->codec_props);
-	if (this->transport)
+
-		spa_hook_remove(&this->transport_listener);
+	impl_remove_hooks(this);
+
 	return 0;
 }
 
@@ -1395,6 +1506,9 @@ impl_init(const struct spa_handle_factory *factory,
 	spa_bt_transport_add_listener(this->transport,
 			&this->transport_listener, &transport_events, this);
 
+	spa_bt_device_add_listener(this->transport->device, &this->device_listener, &device_events, this);
+	try_find_player(this);
+
 	return 0;
 }