aboutsummaryrefslogtreecommitdiff
path: root/src/io_thread.c
blob: 7c080adcbbaea13ced00025369f9f360ddfd9df6 (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
/*
 * Copyright (C) 2003-2011 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.
 */

#include "io_thread.h"

#include <assert.h>

static struct {
	GMutex *mutex;
	GCond *cond;

	GMainContext *context;
	GMainLoop *loop;
	GThread *thread;
} io;

void
io_thread_run(void)
{
	assert(io_thread_inside());
	assert(io.context != NULL);
	assert(io.loop != NULL);

	g_main_loop_run(io.loop);
}

static gpointer
io_thread_func(G_GNUC_UNUSED gpointer arg)
{
	/* lock+unlock to synchronize with io_thread_start(), to be
	   sure that io.thread is set */
	g_mutex_lock(io.mutex);
	g_mutex_unlock(io.mutex);

	io_thread_run();
	return NULL;
}

void
io_thread_init(void)
{
	assert(io.context == NULL);
	assert(io.loop == NULL);
	assert(io.thread == NULL);

	io.mutex = g_mutex_new();
	io.cond = g_cond_new();
	io.context = g_main_context_new();
	io.loop = g_main_loop_new(io.context, false);
}

bool
io_thread_start(GError **error_r)
{
	assert(io.context != NULL);
	assert(io.loop != NULL);
	assert(io.thread == NULL);

	g_mutex_lock(io.mutex);
	io.thread = g_thread_create(io_thread_func, NULL, true, error_r);
	g_mutex_unlock(io.mutex);
	if (io.thread == NULL)
		return false;

	return true;
}

void
io_thread_quit(void)
{
	assert(io.loop != NULL);

	g_main_loop_quit(io.loop);
}

void
io_thread_deinit(void)
{
	if (io.thread != NULL) {
		io_thread_quit();

		g_thread_join(io.thread);
	}

	if (io.loop != NULL)
		g_main_loop_unref(io.loop);

	if (io.context != NULL)
		g_main_context_unref(io.context);

	g_cond_free(io.cond);
	g_mutex_free(io.mutex);
}

GMainContext *
io_thread_context(void)
{
	return io.context;
}

bool
io_thread_inside(void)
{
	return io.thread != NULL && g_thread_self() == io.thread;
}

guint
io_thread_idle_add(GSourceFunc function, gpointer data)
{
	GSource *source = g_idle_source_new();
	g_source_set_callback(source, function, data, NULL);
	guint id = g_source_attach(source, io.context);
	g_source_unref(source);
	return id;
}

GSource *
io_thread_timeout_add(guint interval_ms, GSourceFunc function, gpointer data)
{
	GSource *source = g_timeout_source_new(interval_ms);
	g_source_set_callback(source, function, data, NULL);
	g_source_attach(source, io.context);
	return source;
}

GSource *
io_thread_timeout_add_seconds(guint interval,
			      GSourceFunc function, gpointer data)
{
	GSource *source = g_timeout_source_new_seconds(interval);
	g_source_set_callback(source, function, data, NULL);
	g_source_attach(source, io.context);
	return source;
}

struct call_data {
	GThreadFunc function;
	gpointer data;
	bool done;
	gpointer result;
};

static gboolean
io_thread_call_func(gpointer _data)
{
	struct call_data *data = _data;

	gpointer result = data->function(data->data);

	g_mutex_lock(io.mutex);
	data->done = true;
	data->result = result;
	g_cond_broadcast(io.cond);
	g_mutex_unlock(io.mutex);

	return false;
}

gpointer
io_thread_call(GThreadFunc function, gpointer _data)
{
	assert(io.thread != NULL);

	if (io_thread_inside())
		/* we're already in the I/O thread - no
		   synchronization needed */
		return function(_data);

	struct call_data data = {
		.function = function,
		.data = _data,
		.done = false,
	};

	io_thread_idle_add(io_thread_call_func, &data);

	g_mutex_lock(io.mutex);
	while (!data.done)
		g_cond_wait(io.cond, io.mutex);
	g_mutex_unlock(io.mutex);

	return data.result;
}