mpd/src/OutputAll.cxx

/*
 * Copyright (C) 2003-2011 The Music Player Daemon Project
 * http://www.musicpd.org
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"
#include "OutputAll.hxx"
#include "PlayerControl.hxx"
#include "OutputInternal.hxx"
#include "OutputControl.hxx"
#include "OutputError.hxx"
#include "MusicBuffer.hxx"
#include "MusicPipe.hxx"
#include "MusicChunk.hxx"
#include "system/FatalError.hxx"
#include "util/Error.hxx"
#include "ConfigData.hxx"
#include "ConfigGlobal.hxx"
#include "ConfigOption.hxx"
#include "notify.hxx"

#include <assert.h>
#include <string.h>

static AudioFormat input_audio_format;

static struct audio_output **audio_outputs;
static unsigned int num_audio_outputs;

/**
 * The #MusicBuffer object where consumed chunks are returned.
 */
static MusicBuffer *g_music_buffer;

/**
 * The #MusicPipe object which feeds all audio outputs.  It is filled
 * by audio_output_all_play().
 */
static MusicPipe *g_mp;

/**
 * The "elapsed_time" stamp of the most recently finished chunk.
 */
static float audio_output_all_elapsed_time = -1.0;

unsigned int audio_output_count(void)
{
	return num_audio_outputs;
}

struct audio_output *
audio_output_get(unsigned i)
{
	assert(i < num_audio_outputs);

	assert(audio_outputs[i] != NULL);

	return audio_outputs[i];
}

struct audio_output *
audio_output_find(const char *name)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i) {
		struct audio_output *ao = audio_output_get(i);

		if (strcmp(ao->name, name) == 0)
			return ao;
	}

	/* name not found */
	return NULL;
}

gcc_const
static unsigned
audio_output_config_count(void)
{
	unsigned int nr = 0;
	const struct config_param *param = NULL;

	while ((param = config_get_next_param(CONF_AUDIO_OUTPUT, param)))
		nr++;
	if (!nr)
		nr = 1; /* we'll always have at least one device  */
	return nr;
}

void
audio_output_all_init(struct player_control *pc)
{
	const struct config_param *param = NULL;
	unsigned int i;
	Error error;

	num_audio_outputs = audio_output_config_count();
	audio_outputs = g_new(struct audio_output *, num_audio_outputs);

	const config_param empty;

	for (i = 0; i < num_audio_outputs; i++)
	{
		unsigned int j;

		param = config_get_next_param(CONF_AUDIO_OUTPUT, param);
		if (param == nullptr) {
			/* only allow param to be nullptr if there
			   just one audio output */
			assert(i == 0);
			assert(num_audio_outputs == 1);

			param = &empty;
		}

		audio_output *output = audio_output_new(*param, pc, error);
		if (output == NULL) {
			if (param != NULL)
				FormatFatalError("line %i: %s",
						 param->line,
						 error.GetMessage());
			else
				FatalError(error);
		}

		audio_outputs[i] = output;

		/* require output names to be unique: */
		for (j = 0; j < i; j++) {
			if (!strcmp(output->name, audio_outputs[j]->name)) {
				FormatFatalError("output devices with identical "
						 "names: %s", output->name);
			}
		}
	}
}

void
audio_output_all_finish(void)
{
	unsigned int i;

	for (i = 0; i < num_audio_outputs; i++) {
		audio_output_disable(audio_outputs[i]);
		audio_output_finish(audio_outputs[i]);
	}

	g_free(audio_outputs);
	audio_outputs = NULL;
	num_audio_outputs = 0;
}

void
audio_output_all_enable_disable(void)
{
	for (unsigned i = 0; i < num_audio_outputs; i++) {
		struct audio_output *ao = audio_outputs[i];
		bool enabled;

		ao->mutex.lock();
		enabled = ao->really_enabled;
		ao->mutex.unlock();

		if (ao->enabled != enabled) {
			if (ao->enabled)
				audio_output_enable(ao);
			else
				audio_output_disable(ao);
		}
	}
}

/**
 * Determine if all (active) outputs have finished the current
 * command.
 */
static bool
audio_output_all_finished(void)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i) {
		struct audio_output *ao = audio_outputs[i];

		const ScopeLock protect(ao->mutex);
		if (audio_output_is_open(ao) &&
		    !audio_output_command_is_finished(ao))
			return false;
	}

	return true;
}

static void audio_output_wait_all(void)
{
	while (!audio_output_all_finished())
		audio_output_client_notify.Wait();
}

/**
 * Signals all audio outputs which are open.
 */
static void
audio_output_allow_play_all(void)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i)
		audio_output_allow_play(audio_outputs[i]);
}

static void
audio_output_reset_reopen(struct audio_output *ao)
{
	const ScopeLock protect(ao->mutex);

	if (!ao->open && ao->fail_timer != NULL) {
		g_timer_destroy(ao->fail_timer);
		ao->fail_timer = NULL;
	}
}

/**
 * Resets the "reopen" flag on all audio devices.  MPD should
 * immediately retry to open the device instead of waiting for the
 * timeout when the user wants to start playback.
 */
static void
audio_output_all_reset_reopen(void)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i) {
		struct audio_output *ao = audio_outputs[i];

		audio_output_reset_reopen(ao);
	}
}

/**
 * Opens all output devices which are enabled, but closed.
 *
 * @return true if there is at least open output device which is open
 */
static bool
audio_output_all_update(void)
{
	unsigned int i;
	bool ret = false;

	if (!input_audio_format.IsDefined())
		return false;

	for (i = 0; i < num_audio_outputs; ++i)
		ret = audio_output_update(audio_outputs[i],
					  input_audio_format, *g_mp) || ret;

	return ret;
}

void
audio_output_all_set_replay_gain_mode(enum replay_gain_mode mode)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i)
		audio_output_set_replay_gain_mode(audio_outputs[i], mode);
}

bool
audio_output_all_play(struct music_chunk *chunk, Error &error)
{
	bool ret;
	unsigned int i;

	assert(g_music_buffer != NULL);
	assert(g_mp != NULL);
	assert(chunk != NULL);
	assert(chunk->CheckFormat(input_audio_format));

	ret = audio_output_all_update();
	if (!ret) {
		/* TODO: obtain real error */
		error.Set(output_domain, "Failed to open audio output");
		return false;
	}

	g_mp->Push(chunk);

	for (i = 0; i < num_audio_outputs; ++i)
		audio_output_play(audio_outputs[i]);

	return true;
}

bool
audio_output_all_open(const AudioFormat audio_format,
		      MusicBuffer &buffer,
		      Error &error)
{
	bool ret = false, enabled = false;
	unsigned int i;

	assert(g_music_buffer == NULL || g_music_buffer == &buffer);
	assert((g_mp == NULL) == (g_music_buffer == NULL));

	g_music_buffer = &buffer;

	/* the audio format must be the same as existing chunks in the
	   pipe */
	assert(g_mp == NULL || g_mp->CheckFormat(audio_format));

	if (g_mp == NULL)
		g_mp = new MusicPipe();
	else
		/* if the pipe hasn't been cleared, the the audio
		   format must not have changed */
		assert(g_mp->IsEmpty() || audio_format == input_audio_format);

	input_audio_format = audio_format;

	audio_output_all_reset_reopen();
	audio_output_all_enable_disable();
	audio_output_all_update();

	for (i = 0; i < num_audio_outputs; ++i) {
		if (audio_outputs[i]->enabled)
			enabled = true;

		if (audio_outputs[i]->open)
			ret = true;
	}

	if (!enabled)
		error.Set(output_domain, "All audio outputs are disabled");
	else if (!ret)
		/* TODO: obtain real error */
		error.Set(output_domain, "Failed to open audio output");

	if (!ret)
		/* close all devices if there was an error */
		audio_output_all_close();

	return ret;
}

/**
 * Has the specified audio output already consumed this chunk?
 */
static bool
chunk_is_consumed_in(const struct audio_output *ao,
		     const struct music_chunk *chunk)
{
	if (!ao->open)
		return true;

	if (ao->chunk == NULL)
		return false;

	assert(chunk == ao->chunk || g_mp->Contains(ao->chunk));

	if (chunk != ao->chunk) {
		assert(chunk->next != NULL);
		return true;
	}

	return ao->chunk_finished && chunk->next == NULL;
}

/**
 * Has this chunk been consumed by all audio outputs?
 */
static bool
chunk_is_consumed(const struct music_chunk *chunk)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i) {
		struct audio_output *ao = audio_outputs[i];

		const ScopeLock protect(ao->mutex);
		if (!chunk_is_consumed_in(ao, chunk))
			return false;
	}

	return true;
}

/**
 * There's only one chunk left in the pipe (#g_mp), and all audio
 * outputs have consumed it already.  Clear the reference.
 */
static void
clear_tail_chunk(gcc_unused const struct music_chunk *chunk, bool *locked)
{
	assert(chunk->next == NULL);
	assert(g_mp->Contains(chunk));

	for (unsigned i = 0; i < num_audio_outputs; ++i) {
		struct audio_output *ao = audio_outputs[i];

		/* this mutex will be unlocked by the caller when it's
		   ready */
		ao->mutex.lock();
		locked[i] = ao->open;

		if (!locked[i]) {
			ao->mutex.unlock();
			continue;
		}

		assert(ao->chunk == chunk);
		assert(ao->chunk_finished);
		ao->chunk = NULL;
	}
}

unsigned
audio_output_all_check(void)
{
	const struct music_chunk *chunk;
	bool is_tail;
	struct music_chunk *shifted;
	bool locked[num_audio_outputs];

	assert(g_music_buffer != NULL);
	assert(g_mp != NULL);

	while ((chunk = g_mp->Peek()) != nullptr) {
		assert(!g_mp->IsEmpty());

		if (!chunk_is_consumed(chunk))
			/* at least one output is not finished playing
			   this chunk */
			return g_mp->GetSize();

		if (chunk->length > 0 && chunk->times >= 0.0)
			/* only update elapsed_time if the chunk
			   provides a defined value */
			audio_output_all_elapsed_time = chunk->times;

		is_tail = chunk->next == NULL;
		if (is_tail)
			/* this is the tail of the pipe - clear the
			   chunk reference in all outputs */
			clear_tail_chunk(chunk, locked);

		/* remove the chunk from the pipe */
		shifted = g_mp->Shift();
		assert(shifted == chunk);

		if (is_tail)
			/* unlock all audio outputs which were locked
			   by clear_tail_chunk() */
			for (unsigned i = 0; i < num_audio_outputs; ++i)
				if (locked[i])
					audio_outputs[i]->mutex.unlock();

		/* return the chunk to the buffer */
		g_music_buffer->Return(shifted);
	}

	return 0;
}

bool
audio_output_all_wait(struct player_control *pc, unsigned threshold)
{
	pc->Lock();

	if (audio_output_all_check() < threshold) {
		pc->Unlock();
		return true;
	}

	pc->Wait();
	pc->Unlock();

	return audio_output_all_check() < threshold;
}

void
audio_output_all_pause(void)
{
	unsigned int i;

	audio_output_all_update();

	for (i = 0; i < num_audio_outputs; ++i)
		audio_output_pause(audio_outputs[i]);

	audio_output_wait_all();
}

void
audio_output_all_drain(void)
{
	for (unsigned i = 0; i < num_audio_outputs; ++i)
		audio_output_drain_async(audio_outputs[i]);

	audio_output_wait_all();
}

void
audio_output_all_cancel(void)
{
	unsigned int i;

	/* send the cancel() command to all audio outputs */

	for (i = 0; i < num_audio_outputs; ++i)
		audio_output_cancel(audio_outputs[i]);

	audio_output_wait_all();

	/* clear the music pipe and return all chunks to the buffer */

	if (g_mp != NULL)
		g_mp->Clear(*g_music_buffer);

	/* the audio outputs are now waiting for a signal, to
	   synchronize the cleared music pipe */

	audio_output_allow_play_all();

	/* invalidate elapsed_time */

	audio_output_all_elapsed_time = -1.0;
}

void
audio_output_all_close(void)
{
	unsigned int i;

	for (i = 0; i < num_audio_outputs; ++i)
		audio_output_close(audio_outputs[i]);

	if (g_mp != NULL) {
		assert(g_music_buffer != NULL);

		g_mp->Clear(*g_music_buffer);
		delete g_mp;
		g_mp = NULL;
	}

	g_music_buffer = NULL;

	input_audio_format.Clear();

	audio_output_all_elapsed_time = -1.0;
}

void
audio_output_all_release(void)
{
	unsigned int i;

	for (i = 0; i < num_audio_outputs; ++i)
		audio_output_release(audio_outputs[i]);

	if (g_mp != NULL) {
		assert(g_music_buffer != NULL);

		g_mp->Clear(*g_music_buffer);
		delete g_mp;
		g_mp = NULL;
	}

	g_music_buffer = NULL;

	input_audio_format.Clear();

	audio_output_all_elapsed_time = -1.0;
}

void
audio_output_all_song_border(void)
{
	/* clear the elapsed_time pointer at the beginning of a new
	   song */
	audio_output_all_elapsed_time = 0.0;
}

float
audio_output_all_get_elapsed_time(void)
{
	return audio_output_all_elapsed_time;
}