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/*
* Copyright (C) 2003-2013 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_EVENT_LOOP_HXX
#define MPD_EVENT_LOOP_HXX
#include "check.h"
#include "thread/Id.hxx"
#include "Compiler.h"
#ifdef USE_EPOLL
#include "system/EPollFD.hxx"
#include "thread/Mutex.hxx"
#include "WakeFD.hxx"
#include "SocketMonitor.hxx"
#include <functional>
#include <list>
#include <set>
#else
#include <glib.h>
#endif
#ifdef USE_EPOLL
class TimeoutMonitor;
class IdleMonitor;
class SocketMonitor;
#endif
#include <assert.h>
/**
* An event loop that polls for events on file/socket descriptors.
*
* This class is not thread-safe, all methods must be called from the
* thread that runs it, except where explicitly documented as
* thread-safe.
*
* @see SocketMonitor, MultiSocketMonitor, TimeoutMonitor, IdleMonitor
*/
class EventLoop final
#ifdef USE_EPOLL
: private SocketMonitor
#endif
{
#ifdef USE_EPOLL
struct TimerRecord {
/**
* Projected monotonic_clock_ms() value when this
* timer is due.
*/
const unsigned due_ms;
TimeoutMonitor &timer;
constexpr TimerRecord(TimeoutMonitor &_timer,
unsigned _due_ms)
:due_ms(_due_ms), timer(_timer) {}
bool operator<(const TimerRecord &other) const {
return due_ms < other.due_ms;
}
bool IsDue(unsigned _now_ms) const {
return _now_ms >= due_ms;
}
};
EPollFD epoll;
WakeFD wake_fd;
std::multiset<TimerRecord> timers;
std::list<IdleMonitor *> idle;
Mutex mutex;
std::list<std::function<void()>> calls;
unsigned now_ms;
bool quit;
static constexpr unsigned MAX_EVENTS = 16;
unsigned n_events;
epoll_event events[MAX_EVENTS];
#else
GMainContext *context;
GMainLoop *loop;
#endif
/**
* A reference to the thread that is currently inside Run().
*/
ThreadId thread;
public:
#ifdef USE_EPOLL
struct Default {};
EventLoop(Default dummy=Default());
~EventLoop();
/**
* A caching wrapper for MonotonicClockMS().
*/
unsigned GetTimeMS() const {
return now_ms;
}
/**
* Stop execution of this #EventLoop at the next chance. This
* method is thread-safe and non-blocking: after returning, it
* is not guaranteed that the EventLoop has really stopped.
*/
void Break();
bool AddFD(int _fd, unsigned flags, SocketMonitor &m) {
return epoll.Add(_fd, flags, &m);
}
bool ModifyFD(int _fd, unsigned flags, SocketMonitor &m) {
return epoll.Modify(_fd, flags, &m);
}
/**
* Remove the given #SocketMonitor after the file descriptor
* has been closed. This is like RemoveFD(), but does not
* attempt to use #EPOLL_CTL_DEL.
*/
void Abandon(SocketMonitor &m);
bool RemoveFD(int fd, SocketMonitor &m);
void AddIdle(IdleMonitor &i);
void RemoveIdle(IdleMonitor &i);
void AddTimer(TimeoutMonitor &t, unsigned ms);
void CancelTimer(TimeoutMonitor &t);
void AddCall(std::function<void()> &&f);
/**
* The main function of this class. It will loop until
* Break() gets called. Can be called only once.
*/
void Run();
private:
virtual bool OnSocketReady(unsigned flags) override;
public:
#else
EventLoop()
:context(g_main_context_new()),
loop(g_main_loop_new(context, false)),
thread(ThreadId::Null()) {}
struct Default {};
EventLoop(gcc_unused Default _dummy)
:context(g_main_context_ref(g_main_context_default())),
loop(g_main_loop_new(context, false)),
thread(ThreadId::Null()) {}
~EventLoop() {
g_main_loop_unref(loop);
g_main_context_unref(context);
}
GMainContext *GetContext() {
return context;
}
void WakeUp() {
g_main_context_wakeup(context);
}
void Break() {
g_main_loop_quit(loop);
}
void Run();
guint AddIdle(GSourceFunc function, gpointer data);
GSource *AddTimeout(guint interval_ms,
GSourceFunc function, gpointer data);
GSource *AddTimeoutSeconds(guint interval_s,
GSourceFunc function, gpointer data);
#endif
/**
* Are we currently running inside this EventLoop's thread?
*/
gcc_pure
bool IsInside() const {
assert(!thread.IsNull());
return thread.IsInside();
}
};
#endif /* MAIN_NOTIFY_H */
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