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+/*
+ * Copyright (C) 2003-2014 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.
+ */
+
+#ifndef MPD_DECODER_CONTROL_HXX
+#define MPD_DECODER_CONTROL_HXX
+
+#include "DecoderCommand.hxx"
+#include "AudioFormat.hxx"
+#include "MixRampInfo.hxx"
+#include "thread/Mutex.hxx"
+#include "thread/Cond.hxx"
+#include "thread/Thread.hxx"
+#include "util/Error.hxx"
+
+#include <assert.h>
+#include <stdint.h>
+
+/* damn you, windows.h! */
+#ifdef ERROR
+#undef ERROR
+#endif
+
+class DetachedSong;
+class MusicBuffer;
+class MusicPipe;
+
+enum class DecoderState : uint8_t {
+ STOP = 0,
+ START,
+ DECODE,
+
+ /**
+ * The last "START" command failed, because there was an I/O
+ * error or because no decoder was able to decode the file.
+ * This state will only come after START; once the state has
+ * turned to DECODE, by definition no such error can occur.
+ */
+ ERROR,
+};
+
+struct DecoderControl {
+ /**
+ * The handle of the decoder thread.
+ */
+ Thread thread;
+
+ /**
+ * This lock protects #state and #command.
+ *
+ * This is usually a reference to PlayerControl::mutex, so
+ * that both player thread and decoder thread share a mutex.
+ * This simplifies synchronization with #cond and
+ * #client_cond.
+ */
+ Mutex &mutex;
+
+ /**
+ * Trigger this object after you have modified #command. This
+ * is also used by the decoder thread to notify the caller
+ * when it has finished a command.
+ */
+ Cond cond;
+
+ /**
+ * The trigger of this object's client. It is signalled
+ * whenever an event occurs.
+ *
+ * This is usually a reference to PlayerControl::cond.
+ */
+ Cond &client_cond;
+
+ DecoderState state;
+ DecoderCommand command;
+
+ /**
+ * The error that occurred in the decoder thread. This
+ * attribute is only valid if #state is #DecoderState::ERROR.
+ * The object must be freed when this object transitions to
+ * any other state (usually #DecoderState::START).
+ */
+ Error error;
+
+ bool quit;
+
+ /**
+ * Is the client currently waiting for the DecoderThread? If
+ * false, the DecoderThread may omit invoking Cond::signal(),
+ * reducing the number of system calls.
+ */
+ bool client_is_waiting;
+
+ bool seek_error;
+ bool seekable;
+ double seek_where;
+
+ /** the format of the song file */
+ AudioFormat in_audio_format;
+
+ /** the format being sent to the music pipe */
+ AudioFormat out_audio_format;
+
+ /**
+ * The song currently being decoded. This attribute is set by
+ * the player thread, when it sends the #DecoderCommand::START
+ * command.
+ *
+ * This is a duplicate, and must be freed when this attribute
+ * is cleared.
+ */
+ DetachedSong *song;
+
+ /**
+ * The initial seek position (in milliseconds), e.g. to the
+ * start of a sub-track described by a CUE file.
+ *
+ * This attribute is set by dc_start().
+ */
+ unsigned start_ms;
+
+ /**
+ * The decoder will stop when it reaches this position (in
+ * milliseconds). 0 means don't stop before the end of the
+ * file.
+ *
+ * This attribute is set by dc_start().
+ */
+ unsigned end_ms;
+
+ float total_time;
+
+ /** the #music_chunk allocator */
+ MusicBuffer *buffer;
+
+ /**
+ * The destination pipe for decoded chunks. The caller thread
+ * owns this object, and is responsible for freeing it.
+ */
+ MusicPipe *pipe;
+
+ float replay_gain_db;
+ float replay_gain_prev_db;
+
+ MixRampInfo mix_ramp, previous_mix_ramp;
+
+ /**
+ * @param _mutex see #mutex
+ * @param _client_cond see #client_cond
+ */
+ DecoderControl(Mutex &_mutex, Cond &_client_cond);
+ ~DecoderControl();
+
+ /**
+ * Locks the object.
+ */
+ void Lock() const {
+ mutex.lock();
+ }
+
+ /**
+ * Unlocks the object.
+ */
+ void Unlock() const {
+ mutex.unlock();
+ }
+
+ /**
+ * Signals the object. This function is only valid in the
+ * player thread. The object should be locked prior to
+ * calling this function.
+ */
+ void Signal() {
+ cond.signal();
+ }
+
+ /**
+ * Waits for a signal on the #DecoderControl object. This function
+ * is only valid in the decoder thread. The object must be locked
+ * prior to calling this function.
+ */
+ void Wait() {
+ cond.wait(mutex);
+ }
+
+ /**
+ * Waits for a signal from the decoder thread. This object
+ * must be locked prior to calling this function. This method
+ * is only valid in the player thread.
+ *
+ * Caller must hold the lock.
+ */
+ void WaitForDecoder();
+
+ bool IsIdle() const {
+ return state == DecoderState::STOP ||
+ state == DecoderState::ERROR;
+ }
+
+ gcc_pure
+ bool LockIsIdle() const {
+ Lock();
+ bool result = IsIdle();
+ Unlock();
+ return result;
+ }
+
+ bool IsStarting() const {
+ return state == DecoderState::START;
+ }
+
+ gcc_pure
+ bool LockIsStarting() const {
+ Lock();
+ bool result = IsStarting();
+ Unlock();
+ return result;
+ }
+
+ bool HasFailed() const {
+ assert(command == DecoderCommand::NONE);
+
+ return state == DecoderState::ERROR;
+ }
+
+ gcc_pure
+ bool LockHasFailed() const {
+ Lock();
+ bool result = HasFailed();
+ Unlock();
+ return result;
+ }
+
+ /**
+ * Checks whether an error has occurred, and if so, returns a
+ * copy of the #Error object.
+ *
+ * Caller must lock the object.
+ */
+ gcc_pure
+ Error GetError() const {
+ assert(command == DecoderCommand::NONE);
+ assert(state != DecoderState::ERROR || error.IsDefined());
+
+ Error result;
+ if (state == DecoderState::ERROR)
+ result.Set(error);
+ return result;
+ }
+
+ /**
+ * Like dc_get_error(), but locks and unlocks the object.
+ */
+ gcc_pure
+ Error LockGetError() const {
+ Lock();
+ Error result = GetError();
+ Unlock();
+ return result;
+ }
+
+ /**
+ * Clear the error condition and free the #Error object (if any).
+ *
+ * Caller must lock the object.
+ */
+ void ClearError() {
+ if (state == DecoderState::ERROR) {
+ error.Clear();
+ state = DecoderState::STOP;
+ }
+ }
+
+ /**
+ * Check if the specified song is currently being decoded. If the
+ * decoder is not running currently (or being started), then this
+ * function returns false in any case.
+ *
+ * Caller must lock the object.
+ */
+ gcc_pure
+ bool IsCurrentSong(const DetachedSong &_song) const;
+
+ gcc_pure
+ bool LockIsCurrentSong(const DetachedSong &_song) const {
+ Lock();
+ const bool result = IsCurrentSong(_song);
+ Unlock();
+ return result;
+ }
+
+private:
+ /**
+ * Wait for the command to be finished by the decoder thread.
+ *
+ * To be called from the client thread. Caller must lock the
+ * object.
+ */
+ void WaitCommandLocked() {
+ while (command != DecoderCommand::NONE)
+ WaitForDecoder();
+ }
+
+ /**
+ * Send a command to the decoder thread and synchronously wait
+ * for it to finish.
+ *
+ * To be called from the client thread. Caller must lock the
+ * object.
+ */
+ void SynchronousCommandLocked(DecoderCommand cmd) {
+ command = cmd;
+ Signal();
+ WaitCommandLocked();
+ }
+
+ /**
+ * Send a command to the decoder thread and synchronously wait
+ * for it to finish.
+ *
+ * To be called from the client thread. This method locks the
+ * object.
+ */
+ void LockSynchronousCommand(DecoderCommand cmd) {
+ Lock();
+ ClearError();
+ SynchronousCommandLocked(cmd);
+ Unlock();
+ }
+
+ void LockAsynchronousCommand(DecoderCommand cmd) {
+ Lock();
+ command = cmd;
+ Signal();
+ Unlock();
+ }
+
+public:
+ /**
+ * Start the decoder.
+ *
+ * @param song the song to be decoded; the given instance will be
+ * owned and freed by the decoder
+ * @param start_ms see #DecoderControl
+ * @param end_ms see #DecoderControl
+ * @param pipe the pipe which receives the decoded chunks (owned by
+ * the caller)
+ */
+ void Start(DetachedSong *song, unsigned start_ms, unsigned end_ms,
+ MusicBuffer &buffer, MusicPipe &pipe);
+
+ void Stop();
+
+ bool Seek(double where);
+
+ void Quit();
+
+ const char *GetMixRampStart() const {
+ return mix_ramp.GetStart();
+ }
+
+ const char *GetMixRampEnd() const {
+ return mix_ramp.GetEnd();
+ }
+
+ const char *GetMixRampPreviousEnd() const {
+ return previous_mix_ramp.GetEnd();
+ }
+
+ void SetMixRamp(MixRampInfo &&new_value) {
+ mix_ramp = std::move(new_value);
+ }
+
+ /**
+ * Move mixramp_end to mixramp_prev_end and clear
+ * mixramp_start/mixramp_end.
+ */
+ void CycleMixRamp();
+};
+
+#endif