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/*
* Copyright 2003-2017 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_BRIDGE_HXX
#define MPD_DECODER_BRIDGE_HXX
#include "Client.hxx"
#include "ReplayGainInfo.hxx"
#include "MusicChunkPtr.hxx"
#include <exception>
#include <memory>
class PcmConvert;
struct MusicChunk;
struct DecoderControl;
struct Tag;
/**
* A bridge between the #DecoderClient interface and the MPD core
* (#DecoderControl, #MusicPipe etc.).
*/
class DecoderBridge final : public DecoderClient {
public:
DecoderControl &dc;
/**
* For converting input data to the configured audio format.
* nullptr means no conversion necessary.
*/
PcmConvert *convert = nullptr;
/**
* The time stamp of the next data chunk, in seconds.
*/
double timestamp = 0;
/**
* The time stamp of the next data chunk, in PCM frames.
*/
uint64_t absolute_frame = 0;
/**
* Is the initial seek (to the start position of the sub-song)
* pending, or has it been performed already?
*/
bool initial_seek_pending;
/**
* Is the initial seek currently running? During this time,
* the decoder command is SEEK. This flag is set by
* decoder_get_virtual_command(), when the virtual SEEK
* command is generated for the first time.
*/
bool initial_seek_running = false;
/**
* This flag is set by GetSeekTime(), and checked by
* CommandFinished(). It is used to clean up after seeking.
*/
bool seeking = false;
/**
* The tag from the song object. This is only used for local
* files, because we expect the stream server to send us a new
* tag each time we play it.
*/
std::unique_ptr<Tag> song_tag;
/** the last tag received from the stream */
std::unique_ptr<Tag> stream_tag;
/** the last tag received from the decoder plugin */
std::unique_ptr<Tag> decoder_tag;
/** the chunk currently being written to */
MusicChunkPtr current_chunk;
ReplayGainInfo replay_gain_info;
/**
* A positive serial number for checking if replay gain info
* has changed since the last check.
*/
unsigned replay_gain_serial = 0;
/**
* An error has occurred (in DecoderAPI.cxx), and the plugin
* will be asked to stop.
*/
std::exception_ptr error;
DecoderBridge(DecoderControl &_dc, bool _initial_seek_pending,
std::unique_ptr<Tag> _tag)
:dc(_dc),
initial_seek_pending(_initial_seek_pending),
song_tag(std::move(_tag)) {}
~DecoderBridge();
/**
* Should be read operation be cancelled? That is the case when the
* player thread has sent a command such as "STOP".
*
* Caller must lock the #DecoderControl object.
*/
gcc_pure
bool CheckCancelRead() const noexcept;
/**
* Returns the current chunk the decoder writes to, or allocates a new
* chunk if there is none.
*
* @return the chunk, or NULL if we have received a decoder command
*/
MusicChunk *GetChunk() noexcept;
/**
* Flushes the current chunk.
*
* Caller must not lock the #DecoderControl object.
*/
void FlushChunk();
/* virtual methods from DecoderClient */
void Ready(AudioFormat audio_format,
bool seekable, SignedSongTime duration) override;
DecoderCommand GetCommand() noexcept override;
void CommandFinished() override;
SongTime GetSeekTime() noexcept override;
uint64_t GetSeekFrame() noexcept override;
void SeekError() override;
InputStreamPtr OpenUri(const char *uri) override;
size_t Read(InputStream &is, void *buffer, size_t length) override;
void SubmitTimestamp(double t) override;
DecoderCommand SubmitData(InputStream *is,
const void *data, size_t length,
uint16_t kbit_rate) override;
DecoderCommand SubmitTag(InputStream *is, Tag &&tag) override ;
void SubmitReplayGain(const ReplayGainInfo *replay_gain_info) override;
void SubmitMixRamp(MixRampInfo &&mix_ramp) override;
private:
/**
* Checks if we need an "initial seek". If so, then the
* initial seek is prepared, and the function returns true.
*/
bool PrepareInitialSeek();
/**
* Returns the current decoder command. May return a
* "virtual" synthesized command, e.g. to seek to the
* beginning of the CUE track.
*/
DecoderCommand GetVirtualCommand() noexcept;
DecoderCommand LockGetVirtualCommand() noexcept;
/**
* Sends a #Tag as-is to the #MusicPipe. Flushes the current
* chunk (DecoderBridge::chunk) if there is one.
*/
DecoderCommand DoSendTag(const Tag &tag);
bool UpdateStreamTag(InputStream *is);
};
#endif
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