C++ player_lock函数代码示例

/**
 * Wrapper for audio_output_all_open().  Upon failure, it pauses the
 * player.
 *
 * @return true on success
 */
static bool
player_open_output(struct player *player)
{
	assert(audio_format_defined(&player->play_audio_format));
	assert(pc.state == PLAYER_STATE_PLAY ||
	       pc.state == PLAYER_STATE_PAUSE);

	if (audio_output_all_open(&player->play_audio_format, player_buffer)) {
		player->output_open = true;
		player->paused = false;

		player_lock();
		pc.state = PLAYER_STATE_PLAY;
		player_unlock();

		return true;
	} else {
		player->output_open = false;

		/* pause: the user may resume playback as soon as an
		   audio output becomes available */
		player->paused = true;

		player_lock();
		pc.error = PLAYER_ERROR_AUDIO;
		pc.state = PLAYER_STATE_PAUSE;
		player_unlock();

		return false;
	}
}

/**
 * This is the "PLAYLIST" event handler.  It is invoked by the player
 * thread whenever it requests a new queued song, or when it exits.
 */
void
playlist_sync(struct playlist *playlist, struct player_control *pc)
{
	if (!playlist->playing)
		/* this event has reached us out of sync: we aren't
		   playing anymore; ignore the event */
		return;

	player_lock(pc);
	enum player_state pc_state = pc_get_state(pc);
	const struct song *pc_next_song = pc->next_song;
	player_unlock(pc);

	if (pc_state == PLAYER_STATE_STOP)
		/* the player thread has stopped: check if playback
		   should be restarted with the next song.  That can
		   happen if the playlist isn't filling the queue fast
		   enough */
		playlist_resume_playback(playlist, pc);
	else {
		/* check if the player thread has already started
		   playing the queued song */
		if (pc_next_song == NULL && playlist->queued != -1)
			playlist_song_started(playlist, pc);

		player_lock(pc);
		pc_next_song = pc->next_song;
		player_unlock(pc);

		/* make sure the queued song is always set (if
		   possible) */
		if (pc_next_song == NULL && playlist->queued < 0)
			playlist_update_queued_song(playlist, pc, NULL);
	}
}

/**
 * The decoder has acknowledged the "START" command (see
 * player_wait_for_decoder()).  This function checks if the decoder
 * initialization has completed yet.
 *
 * The player lock is not held.
 */
static bool
player_check_decoder_startup(struct player *player)
{
	struct player_control *pc = player->pc;
	struct decoder_control *dc = player->dc;

	assert(player->decoder_starting);

	decoder_lock(dc);

	GError *error = dc_get_error(dc);
	if (error != NULL) {
		/* the decoder failed */
		decoder_unlock(dc);

		player_lock(pc);
		pc_set_error(pc, PLAYER_ERROR_DECODER, error);
		player_unlock(pc);

		return false;
	} else if (!decoder_is_starting(dc)) {
		/* the decoder is ready and ok */

		decoder_unlock(dc);

		if (player->output_open &&
		    !audio_output_all_wait(pc, 1))
			/* the output devices havn't finished playing
			   all chunks yet - wait for that */
			return true;

		player_lock(pc);
		pc->total_time = real_song_duration(dc->song, dc->total_time);
		pc->audio_format = dc->in_audio_format;
		player_unlock(pc);

		player->play_audio_format = dc->out_audio_format;
		player->decoder_starting = false;

		if (!player->paused && !player_open_output(player)) {
			char *uri = song_get_uri(dc->song);
			g_warning("problems opening audio device "
				  "while playing \"%s\"", uri);
			g_free(uri);

			return true;
		}

		return true;
	} else {
		/* the decoder is not yet ready; wait
		   some more */
		player_wait_decoder(pc, dc);
		decoder_unlock(dc);

		return true;
	}
}

/**
 * After the decoder has been started asynchronously, wait for the
 * "START" command to finish.  The decoder may not be initialized yet,
 * i.e. there is no audio_format information yet.
 *
 * The player lock is not held.
 */
static bool
player_wait_for_decoder(struct player *player)
{
	struct player_control *pc = player->pc;
	struct decoder_control *dc = player->dc;

	assert(player->queued || pc->command == PLAYER_COMMAND_SEEK);
	assert(pc->next_song != NULL);

	player->queued = false;

	GError *error = dc_lock_get_error(dc);
	if (error != NULL) {
		player_lock(pc);
		pc_set_error(pc, PLAYER_ERROR_DECODER, error);

		song_free(pc->next_song);
		pc->next_song = NULL;

		player_unlock(pc);

		return false;
	}

	if (player->song != NULL)
		song_free(player->song);

	player->song = pc->next_song;
	player->elapsed_time = 0.0;

	/* set the "starting" flag, which will be cleared by
	   player_check_decoder_startup() */
	player->decoder_starting = true;

	player_lock(pc);

	/* update player_control's song information */
	pc->total_time = song_get_duration(pc->next_song);
	pc->bit_rate = 0;
	audio_format_clear(&pc->audio_format);

	/* clear the queued song */
	pc->next_song = NULL;

	player_unlock(pc);

	/* call syncPlaylistWithQueue() in the main thread */
	event_pipe_emit(PIPE_EVENT_PLAYLIST);

	return true;
}

/**
 * This is called at the border between two songs: the audio output
 * has consumed all chunks of the current song, and we should start
 * sending chunks from the next one.
 *
 * The player lock is not held.
 *
 * @return true on success, false on error (playback will be stopped)
 */
static bool
player_song_border(struct player *player)
{
	player->xfade = XFADE_UNKNOWN;

	char *uri = song_get_uri(player->song);
	g_message("played \"%s\"", uri);
	g_free(uri);

	music_pipe_free(player->pipe);
	player->pipe = player->dc->pipe;

	audio_output_all_song_border();

	if (!player_wait_for_decoder(player))
		return false;

	struct player_control *const pc = player->pc;
	player_lock(pc);

	if (pc->border_pause) {
		player->paused = true;
		pc->state = PLAYER_STATE_PAUSE;
	}

	player_unlock(pc);

	return true;
}

static void
player_command(enum player_command cmd)
{
	player_lock();
	player_command_locked(cmd);
	player_unlock();
}

void player_pause(void)
{
	player_lock();

	if (consumer_status == CS_STOPPED) {
		__producer_play();
		if (producer_status == PS_PLAYING) {
			__consumer_play();
			if (consumer_status != CS_PLAYING)
				__producer_stop();
		}
		__player_status_changed();
		if (consumer_status == CS_PLAYING)
			__prebuffer();
		player_unlock();
		return;
	}

	if (ip && ip_is_remote(ip)) {
		/* pausing not allowed */
		player_unlock();
		return;
	}
	__producer_pause();
	__consumer_pause();
	__player_status_changed();
	player_unlock();
}

void player_play_file(struct track_info *ti)
{
	player_lock();
	__producer_set_file(ti);
	if (producer_status == PS_UNLOADED) {
		__consumer_stop();
		goto out;
	}

	/* PS_STOPPED */
	__producer_play();

	/* PS_UNLOADED,PS_PLAYING */
	if (producer_status == PS_UNLOADED) {
		__consumer_stop();
		goto out;
	}

	/* PS_PLAYING */
	if (consumer_status == CS_STOPPED) {
		__consumer_play();
		if (consumer_status == CS_STOPPED)
			__producer_stop();
	} else {
		op_drop();
		change_sf(1);
	}
out:
	__player_status_changed();
	if (producer_status == PS_PLAYING)
		__prebuffer();
	player_unlock();
}

static void
player_command(struct player_control *pc, enum player_command cmd)
{
	player_lock(pc);
	player_command_locked(pc, cmd);
	player_unlock(pc);
}

static void
player_command_finished(struct player_control *pc)
{
	player_lock(pc);
	player_command_finished_locked(pc);
	player_unlock(pc);
}

/**
 * Plays a #music_chunk object (after applying software volume).  If
 * it contains a (stream) tag, copy it to the current song, so MPD's
 * playlist reflects the new stream tag.
 *
 * Player lock is not held.
 */
static bool
play_chunk(struct player_control *pc,
	   struct song *song, struct music_chunk *chunk,
	   const struct audio_format *format)
{
	assert(music_chunk_check_format(chunk, format));

	if (chunk->tag != NULL)
		update_song_tag(song, chunk->tag);

	if (chunk->length == 0) {
		music_buffer_return(player_buffer, chunk);
		return true;
	}

	player_lock(pc);
	pc->bit_rate = chunk->bit_rate;
	player_unlock(pc);

	/* send the chunk to the audio outputs */

	if (!audio_output_all_play(chunk))
		return false;

	pc->total_play_time += (double)chunk->length /
		audio_format_time_to_size(format);
	return true;
}

void
pc_set_border_pause(struct player_control *pc, bool border_pause)
{
	player_lock(pc);
	pc->border_pause = border_pause;
	player_unlock(pc);
}

void player_stop(void)
{
	player_lock();
	__consumer_stop();
	__producer_stop();
	__player_status_changed();
	player_unlock();
}

void
pc_clear_error(void)
{
	player_lock();
	pc.error = PLAYER_ERROR_NOERROR;
	pc.errored_song = NULL;
	player_unlock();
}

void
pc_enqueue_song(struct song *song)
{
	assert(song != NULL);

	player_lock();
	pc_enqueue_song_locked(song);
	player_unlock();
}