summaryrefslogtreecommitdiff
path: root/src/event/Loop.hxx
blob: 885e746797e3b9307f01720a856be9a4c0eb1eda (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
/*
 * 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_INTERNAL_EVENTLOOP
#include "PollGroup.hxx"
#include "thread/Mutex.hxx"
#include "WakeFD.hxx"
#include "SocketMonitor.hxx"

#include <functional>
#include <list>
#include <set>
#endif

#ifdef USE_GLIB_EVENTLOOP
#include <glib.h>
#endif

#ifdef USE_INTERNAL_EVENTLOOP
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_INTERNAL_EVENTLOOP
	: private SocketMonitor
#endif
{
#ifdef USE_INTERNAL_EVENTLOOP
	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;
		}
	};

	WakeFD wake_fd;

	std::multiset<TimerRecord> timers;
	std::list<IdleMonitor *> idle;

	Mutex mutex;
	std::list<std::function<void()>> calls;

	unsigned now_ms;

	bool quit;

	PollGroup poll_group;
	PollResult poll_result;
#endif

#ifdef USE_GLIB_EVENTLOOP
	GMainContext *context;
	GMainLoop *loop;
#endif

	/**
	 * A reference to the thread that is currently inside Run().
	 */
	ThreadId thread;

public:
#ifdef USE_INTERNAL_EVENTLOOP
	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 poll_group.Add(_fd, flags, &m);
	}

	bool ModifyFD(int _fd, unsigned flags, SocketMonitor &m) {
		return poll_group.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.
	 */
	bool Abandon(int fd, 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);

	/**
	 * Schedule a function to be called inside the thread.
	 *
	 * This method is thread-safe.
	 */
	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:
#endif

#ifdef USE_GLIB_EVENTLOOP
	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 */