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/*
* Copyright 2003-2021 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_OUTPUT_SNAPCAST_INTERNAL_HXX
#define MPD_OUTPUT_SNAPCAST_INTERNAL_HXX
#include "output/Interface.hxx"
#include "output/Timer.hxx"
#include "thread/Mutex.hxx"
#include "event/ServerSocket.hxx"
#include "util/AllocatedArray.hxx"
#include "util/IntrusiveList.hxx"
#include <memory>
struct ConfigBlock;
class SnapcastClient;
class PreparedEncoder;
class Encoder;
class SnapcastOutput final : AudioOutput, ServerSocket {
/**
* True if the audio output is open and accepts client
* connections.
*/
bool open;
/**
* The configured encoder plugin.
*/
std::unique_ptr<PreparedEncoder> prepared_encoder;
Encoder *encoder = nullptr;
AllocatedArray<std::byte> codec_header;
/**
* Number of bytes which were fed into the encoder, without
* ever receiving new output. This is used to estimate
* whether MPD should manually flush the encoder, to avoid
* buffer underruns in the client.
*/
size_t unflushed_input = 0;
/**
* A #Timer object to synchronize this output with the
* wallclock.
*/
Timer *timer;
/**
* A linked list containing all clients which are currently
* connected.
*/
IntrusiveList<SnapcastClient> clients;
public:
/**
* This mutex protects the listener socket and the client
* list.
*/
mutable Mutex mutex;
SnapcastOutput(EventLoop &_loop, const ConfigBlock &block);
~SnapcastOutput() noexcept override;
static AudioOutput *Create(EventLoop &event_loop,
const ConfigBlock &block) {
return new SnapcastOutput(event_loop, block);
}
using ServerSocket::GetEventLoop;
void Bind();
void Unbind() noexcept;
/**
* Check whether there is at least one client.
*
* Caller must lock the mutex.
*/
[[gnu::pure]]
bool HasClients() const noexcept {
return !clients.empty();
}
/**
* Check whether there is at least one client.
*/
[[gnu::pure]]
bool LockHasClients() const noexcept {
const std::lock_guard<Mutex> protect(mutex);
return HasClients();
}
/**
* Caller must lock the mutex.
*/
void AddClient(UniqueSocketDescriptor fd) noexcept;
/**
* Removes a client from the snapcast_output.clients linked list.
*
* Caller must lock the mutex.
*/
void RemoveClient(SnapcastClient &client) noexcept;
/**
* Caller must lock the mutex.
*
* Throws on error.
*/
void OpenEncoder(AudioFormat &audio_format);
const char *GetCodecName() const noexcept {
return "pcm";
}
ConstBuffer<void> GetCodecHeader() const noexcept {
ConstBuffer<std::byte> result(codec_header);
return result.ToVoid();
}
/* virtual methods from class AudioOutput */
void Enable() override {
Bind();
}
void Disable() noexcept override {
Unbind();
}
void Open(AudioFormat &audio_format) override;
void Close() noexcept override;
// TODO: void Interrupt() noexcept override;
std::chrono::steady_clock::duration Delay() const noexcept override;
// TODO: void SendTag(const Tag &tag) override;
size_t Play(const void *chunk, size_t size) override;
// TODO: void Drain() override;
void Cancel() noexcept override;
bool Pause() override;
private:
void BroadcastWireChunk(ConstBuffer<void> payload,
std::chrono::steady_clock::time_point t) noexcept;
/* virtual methods from class ServerSocket */
void OnAccept(UniqueSocketDescriptor fd,
SocketAddress address, int uid) noexcept override;
};
#endif