/
SDL_sysmutex.c
153 lines (134 loc) · 3.55 KB
/
SDL_sysmutex.c
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
/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 Sam Lantinga
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
#include <pthread.h>
#include "SDL_thread.h"
#if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \
!SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
#define FAKE_RECURSIVE_MUTEX
#endif
struct SDL_mutex {
pthread_mutex_t id;
#if FAKE_RECURSIVE_MUTEX
int recursive;
pthread_t owner;
#endif
};
SDL_mutex *SDL_CreateMutex (void)
{
SDL_mutex *mutex;
pthread_mutexattr_t attr;
/* Allocate the structure */
mutex = (SDL_mutex *)SDL_calloc(1, sizeof(*mutex));
if ( mutex ) {
pthread_mutexattr_init(&attr);
#if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
#elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
#else
/* No extra attributes necessary */
#endif
if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
SDL_SetError("pthread_mutex_init() failed");
SDL_free(mutex);
mutex = NULL;
}
} else {
SDL_OutOfMemory();
}
return(mutex);
}
void SDL_DestroyMutex(SDL_mutex *mutex)
{
if ( mutex ) {
pthread_mutex_destroy(&mutex->id);
SDL_free(mutex);
}
}
/* Lock the mutex */
int SDL_mutexP(SDL_mutex *mutex)
{
int retval;
#if FAKE_RECURSIVE_MUTEX
pthread_t this_thread;
#endif
if ( mutex == NULL ) {
SDL_SetError("Passed a NULL mutex");
return -1;
}
retval = 0;
#if FAKE_RECURSIVE_MUTEX
this_thread = pthread_self();
if ( mutex->owner == this_thread ) {
++mutex->recursive;
} else {
/* The order of operations is important.
We set the locking thread id after we obtain the lock
so unlocks from other threads will fail.
*/
if ( pthread_mutex_lock(&mutex->id) == 0 ) {
mutex->owner = this_thread;
mutex->recursive = 0;
} else {
SDL_SetError("pthread_mutex_lock() failed");
retval = -1;
}
}
#else
if ( pthread_mutex_lock(&mutex->id) < 0 ) {
SDL_SetError("pthread_mutex_lock() failed");
retval = -1;
}
#endif
return retval;
}
int SDL_mutexV(SDL_mutex *mutex)
{
int retval;
if ( mutex == NULL ) {
SDL_SetError("Passed a NULL mutex");
return -1;
}
retval = 0;
#if FAKE_RECURSIVE_MUTEX
/* We can only unlock the mutex if we own it */
if ( pthread_self() == mutex->owner ) {
if ( mutex->recursive ) {
--mutex->recursive;
} else {
/* The order of operations is important.
First reset the owner so another thread doesn't lock
the mutex and set the ownership before we reset it,
then release the lock semaphore.
*/
mutex->owner = 0;
pthread_mutex_unlock(&mutex->id);
}
} else {
SDL_SetError("mutex not owned by this thread");
retval = -1;
}
#else
if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
SDL_SetError("pthread_mutex_unlock() failed");
retval = -1;
}
#endif /* FAKE_RECURSIVE_MUTEX */
return retval;
}