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/*
* Copyright 2003-2016 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.
*/
/** \file
*
* Internal declarations for the "httpd" audio output plugin.
*/
#ifndef MPD_OUTPUT_HTTPD_INTERNAL_H
#define MPD_OUTPUT_HTTPD_INTERNAL_H
#include "HttpdClient.hxx"
#include "output/Internal.hxx"
#include "output/Timer.hxx"
#include "thread/Mutex.hxx"
#include "event/ServerSocket.hxx"
#include "event/DeferredMonitor.hxx"
#include "util/Cast.hxx"
#include "Compiler.h"
#include <boost/intrusive/list.hpp>
#include <queue>
#include <list>
struct ConfigBlock;
class EventLoop;
class ServerSocket;
class HttpdClient;
class Page;
class PreparedEncoder;
class Encoder;
struct Tag;
class HttpdOutput final : ServerSocket, DeferredMonitor {
AudioOutput base;
/**
* True if the audio output is open and accepts client
* connections.
*/
bool open;
/**
* The configured encoder plugin.
*/
PreparedEncoder *prepared_encoder = nullptr;
Encoder *encoder;
/**
* 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;
public:
/**
* The MIME type produced by the #encoder.
*/
const char *content_type;
/**
* This mutex protects the listener socket and the client
* list.
*/
mutable Mutex mutex;
/**
* This condition gets signalled when an item is removed from
* #pages.
*/
Cond cond;
private:
/**
* A #Timer object to synchronize this output with the
* wallclock.
*/
Timer *timer;
/**
* The header page, which is sent to every client on connect.
*/
Page *header;
/**
* The metadata, which is sent to every client.
*/
Page *metadata;
/**
* The page queue, i.e. pages from the encoder to be
* broadcasted to all clients. This container is necessary to
* pass pages from the OutputThread to the IOThread. It is
* protected by #mutex, and removing signals #cond.
*/
std::queue<Page *, std::list<Page *>> pages;
public:
/**
* The configured name.
*/
char const *name;
/**
* The configured genre.
*/
char const *genre;
/**
* The configured website address.
*/
char const *website;
private:
/**
* A linked list containing all clients which are currently
* connected.
*/
boost::intrusive::list<HttpdClient,
boost::intrusive::constant_time_size<true>> clients;
/**
* A temporary buffer for the httpd_output_read_page()
* function.
*/
char buffer[32768];
/**
* The maximum and current number of clients connected
* at the same time.
*/
unsigned clients_max;
public:
HttpdOutput(EventLoop &_loop, const ConfigBlock &block);
~HttpdOutput();
operator AudioOutput *() {
return &base;
}
#if CLANG_OR_GCC_VERSION(4,7)
constexpr
#endif
static HttpdOutput *Cast(AudioOutput *ao) {
return &ContainerCast(*ao, &HttpdOutput::base);
}
using DeferredMonitor::GetEventLoop;
void Bind();
void Unbind();
/**
* Caller must lock the mutex.
*
* Throws #std::runtime_error on error.
*/
void OpenEncoder(AudioFormat &audio_format);
/**
* Caller must lock the mutex.
*/
void Open(AudioFormat &audio_format);
/**
* Caller must lock the mutex.
*/
void Close();
/**
* Check whether there is at least one client.
*
* Caller must lock the mutex.
*/
gcc_pure
bool HasClients() const {
return !clients.empty();
}
/**
* Check whether there is at least one client.
*/
gcc_pure
bool LockHasClients() const {
const ScopeLock protect(mutex);
return HasClients();
}
void AddClient(int fd);
/**
* Removes a client from the httpd_output.clients linked list.
*/
void RemoveClient(HttpdClient &client);
/**
* Sends the encoder header to the client. This is called
* right after the response headers have been sent.
*/
void SendHeader(HttpdClient &client) const;
gcc_pure
std::chrono::steady_clock::duration Delay() const;
/**
* Reads data from the encoder (as much as available) and
* returns it as a new #page object.
*/
Page *ReadPage();
/**
* Broadcasts a page struct to all clients.
*
* Mutext must not be locked.
*/
void BroadcastPage(Page *page);
/**
* Broadcasts data from the encoder to all clients.
*/
void BroadcastFromEncoder();
/**
* Throws #std::runtime_error on error.
*/
void EncodeAndPlay(const void *chunk, size_t size);
void SendTag(const Tag &tag);
size_t Play(const void *chunk, size_t size);
void CancelAllClients();
private:
virtual void RunDeferred() override;
void OnAccept(int fd, SocketAddress address, int uid) override;
};
extern const class Domain httpd_output_domain;
#endif
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