zenilib: zenilib/jni/external/sdl/src/thread/pthread/SDL_sysmutex.c Source File

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SDL_sysmutex.c
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1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "SDL_config.h"
22
23 #define _GNU_SOURCE
24 #include <pthread.h>
25 #include <errno.h>
26
27 #include "SDL_thread.h"
28
29 #if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \
30 !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
31 #define FAKE_RECURSIVE_MUTEX 1
32 #endif
33
34 struct SDL_mutex
35 {
36 pthread_mutex_t id;
37 #if FAKE_RECURSIVE_MUTEX
38 int recursive;
39 pthread_t owner;
40 #endif
41 };
42
43 SDL_mutex *
44 SDL_CreateMutex(void)
45 {
46 SDL_mutex *mutex;
47 pthread_mutexattr_t attr;
48
49 /* Allocate the structure */
50 mutex = (SDL_mutex *) SDL_calloc(1, sizeof(*mutex));
51 if (mutex) {
52 pthread_mutexattr_init(&attr);
53 #if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
54 pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
55 #elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
56 pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
57 #else
58 /* No extra attributes necessary */
59 #endif
60 if (pthread_mutex_init(&mutex->id, &attr) != 0) {
61 SDL_SetError("pthread_mutex_init() failed");
62 SDL_free(mutex);
63 mutex = NULL;
64 }
65 } else {
66 SDL_OutOfMemory();
67 }
68 return (mutex);
69 }
70
71 void
72 SDL_DestroyMutex(SDL_mutex * mutex)
73 {
74 if (mutex) {
75 pthread_mutex_destroy(&mutex->id);
76 SDL_free(mutex);
77 }
78 }
79
80 /* Lock the mutex */
81 int
82 SDL_LockMutex(SDL_mutex * mutex)
83 {
84 #if FAKE_RECURSIVE_MUTEX
85 pthread_t this_thread;
86 #endif
87
88 if (mutex == NULL) {
89 return SDL_SetError("Passed a NULL mutex");
90 }
91
92 #if FAKE_RECURSIVE_MUTEX
93 this_thread = pthread_self();
94 if (mutex->owner == this_thread) {
95 ++mutex->recursive;
96 } else {
97 /* The order of operations is important.
98 We set the locking thread id after we obtain the lock
99 so unlocks from other threads will fail.
100 */
101 if (pthread_mutex_lock(&mutex->id) == 0) {
102 mutex->owner = this_thread;
103 mutex->recursive = 0;
104 } else {
105 return SDL_SetError("pthread_mutex_lock() failed");
106 }
107 }
108 #else
109 if (pthread_mutex_lock(&mutex->id) < 0) {
110 return SDL_SetError("pthread_mutex_lock() failed");
111 }
112 #endif
113 return 0;
114 }
115
116 int
117 SDL_TryLockMutex(SDL_mutex * mutex)
118 {
119 int retval;
120 #if FAKE_RECURSIVE_MUTEX
121 pthread_t this_thread;
122 #endif
123
124 if (mutex == NULL) {
125 return SDL_SetError("Passed a NULL mutex");
126 }
127
128 retval = 0;
129 #if FAKE_RECURSIVE_MUTEX
130 this_thread = pthread_self();
131 if (mutex->owner == this_thread) {
132 ++mutex->recursive;
133 } else {
134 /* The order of operations is important.
135 We set the locking thread id after we obtain the lock
136 so unlocks from other threads will fail.
137 */
138 if (pthread_mutex_lock(&mutex->id) == 0) {
139 mutex->owner = this_thread;
140 mutex->recursive = 0;
141 } else if (errno == EBUSY) {
142 retval = SDL_MUTEX_TIMEDOUT;
143 } else {
144 retval = SDL_SetError("pthread_mutex_trylock() failed");
145 }
146 }
147 #else
148 if (pthread_mutex_trylock(&mutex->id) != 0) {
149 if (errno == EBUSY) {
150 retval = SDL_MUTEX_TIMEDOUT;
151 } else {
152 retval = SDL_SetError("pthread_mutex_trylock() failed");
153 }
154 }
155 #endif
156 return retval;
157 }
158
159 int
160 SDL_UnlockMutex(SDL_mutex * mutex)
161 {
162 if (mutex == NULL) {
163 return SDL_SetError("Passed a NULL mutex");
164 }
165
166 #if FAKE_RECURSIVE_MUTEX
167 /* We can only unlock the mutex if we own it */
168 if (pthread_self() == mutex->owner) {
169 if (mutex->recursive) {
170 --mutex->recursive;
171 } else {
172 /* The order of operations is important.
173 First reset the owner so another thread doesn't lock
174 the mutex and set the ownership before we reset it,
175 then release the lock semaphore.
176 */
177 mutex->owner = 0;
178 pthread_mutex_unlock(&mutex->id);
179 }
180 } else {
181 return SDL_SetError("mutex not owned by this thread");
182 }
183
184 #else
185 if (pthread_mutex_unlock(&mutex->id) < 0) {
186 return SDL_SetError("pthread_mutex_unlock() failed");
187 }
188 #endif /* FAKE_RECURSIVE_MUTEX */
189
190 return 0;
191 }
192
193 /* vi: set ts=4 sw=4 expandtab: */
SDL_calloc
DECLSPEC void *SDLCALL SDL_calloc(size_t nmemb, size_t size)
NULL
#define NULL
Definition: ftobjs.h:61
SDL_LockMutex
DECLSPEC int SDLCALL SDL_LockMutex(SDL_mutex *mutex)
Definition: SDL_sysmutex.c:73
SDL_CreateMutex
DECLSPEC SDL_mutex *SDLCALL SDL_CreateMutex(void)
Definition: SDL_sysmutex.c:38
SDL_free
DECLSPEC void SDLCALL SDL_free(void *mem)
id
GLuint id
Definition: gl2ext.h:1142
SDL_config.h
SDL_UnlockMutex
DECLSPEC int SDLCALL SDL_UnlockMutex(SDL_mutex *mutex)
Definition: SDL_sysmutex.c:160
SDL_TryLockMutex
DECLSPEC int SDLCALL SDL_TryLockMutex(SDL_mutex *mutex)
Definition: SDL_sysmutex.c:103
SDL_SetError
DECLSPEC int SDLCALL SDL_SetError(const char *fmt,...)
Definition: SDL_error.c:53
SDL_OutOfMemory
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
SDL_mutex
struct SDL_mutex SDL_mutex
Definition: SDL_mutex.h:59
SDL_DestroyMutex
DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex)
Definition: SDL_sysmutex.c:61
SDL_MUTEX_TIMEDOUT
#define SDL_MUTEX_TIMEDOUT
Definition: SDL_mutex.h:44