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
|
/* Support for thread stuff.
*
* JC & KM 9/5/94
* Modified:
* 28/11/94 JC
* - return(0) missing from tidy_thread_info()
* 4/8/99 RP JC
* - reorganised for POSIX
* 28/3/11
* - moved to vips_ namespace
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser 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
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG_IO
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <vips/vips.h>
#include <vips/thread.h>
void
vips_semaphore_init( VipsSemaphore *s, int v, char *name )
{
s->v = v;
s->name = name;
s->mutex = vips_g_mutex_new();
s->cond = vips_g_cond_new();
}
void
vips_semaphore_destroy( VipsSemaphore *s )
{
VIPS_FREEF( vips_g_mutex_free, s->mutex );
VIPS_FREEF( vips_g_cond_free, s->cond );
}
/* Add n to the semaphore and signal any threads that are blocked waiting
* a change.
*/
int
vips_semaphore_upn( VipsSemaphore *s, int n )
{
int value_after_op;
g_mutex_lock( s->mutex );
s->v += n;
value_after_op = s->v;
/* If we are only incrementing by one, we only need to wake a single
* thread. If we are incrementing by a lot, we must wake all threads.
*/
if( n == 1 )
g_cond_signal( s->cond );
else
g_cond_broadcast( s->cond );
g_mutex_unlock( s->mutex );
#ifdef DEBUG_IO
printf( "vips_semaphore_upn(\"%s\",%d) = %d\n",
s->name, n, value_after_op );
if( value_after_op > 1 )
vips_error( "vips_semaphore_upn", "up over 1!" );
#endif /*DEBUG_IO*/
return( value_after_op );
}
/* Increment the semaphore.
*/
int
vips_semaphore_up( VipsSemaphore *s )
{
return( vips_semaphore_upn( s, 1 ) );
}
/* Wait for sem>n, then subtract n.
* Returns -1 when the monotonic time in @end_time was passed.
*/
static int
vips__semaphore_downn_until( VipsSemaphore *s, int n, gint64 end_time )
{
int value_after_op;
VIPS_GATE_START( "vips__semaphore_downn_until: wait" );
g_mutex_lock( s->mutex );
while( s->v < n ) {
if( end_time == -1 )
g_cond_wait( s->cond, s->mutex );
else if( !g_cond_wait_until( s->cond, s->mutex, end_time ) ) {
/* timeout has passed.
*/
g_mutex_unlock( s->mutex );
VIPS_GATE_STOP( "vips__semaphore_downn_until: wait" );
return( -1 );
}
}
s->v -= n;
value_after_op = s->v;
g_mutex_unlock( s->mutex );
#ifdef DEBUG_IO
printf( "vips__semaphore_downn_until(\"%s\",%d): %d\n",
s->name, n, value_after_op );
#endif /*DEBUG_IO*/
VIPS_GATE_STOP( "vips__semaphore_downn_until: wait" );
return( value_after_op );
}
/* Wait for sem>n, then subtract n. n must be >= 0. Returns the new semaphore
* value.
*/
int
vips_semaphore_downn( VipsSemaphore *s, int n )
{
g_assert( n >= 0 );
return( vips__semaphore_downn_until( s, n, -1 ) );
}
/* Wait for sem > 0, then decrement. Returns the new semaphore value.
*/
int
vips_semaphore_down( VipsSemaphore *s )
{
return( vips__semaphore_downn_until( s, 1, -1 ) );
}
/* Wait for sem > 0, then decrement.
* Returns -1 when @timeout (in microseconds) has passed, or the new
* semaphore value.
*/
int
vips_semaphore_down_timeout( VipsSemaphore *s, gint64 timeout )
{
gint64 end_time = g_get_monotonic_time () + timeout;
return( vips__semaphore_downn_until( s, 1, end_time ) );
}
|
