e14743d1 |
1 | /* |
2 | SDL - Simple DirectMedia Layer |
3 | Copyright (C) 1997-2009 Sam Lantinga |
4 | |
5 | This library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | This library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with this library; if not, write to the Free Software |
17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
18 | |
19 | Sam Lantinga |
20 | slouken@libsdl.org |
21 | */ |
22 | #include "SDL_config.h" |
23 | |
24 | /* System independent thread management routines for SDL */ |
25 | |
26 | #include "SDL_mutex.h" |
27 | #include "SDL_thread.h" |
28 | #include "SDL_thread_c.h" |
29 | #include "SDL_systhread.h" |
30 | |
31 | #define ARRAY_CHUNKSIZE 32 |
32 | /* The array of threads currently active in the application |
33 | (except the main thread) |
34 | The manipulation of an array here is safer than using a linked list. |
35 | */ |
36 | static int SDL_maxthreads = 0; |
37 | static int SDL_numthreads = 0; |
38 | static SDL_Thread **SDL_Threads = NULL; |
39 | static SDL_mutex *thread_lock = NULL; |
40 | |
41 | int SDL_ThreadsInit(void) |
42 | { |
43 | int retval; |
44 | |
45 | retval = 0; |
46 | thread_lock = SDL_CreateMutex(); |
47 | if ( thread_lock == NULL ) { |
48 | retval = -1; |
49 | } |
50 | return(retval); |
51 | } |
52 | |
53 | /* This should never be called... |
54 | If this is called by SDL_Quit(), we don't know whether or not we should |
55 | clean up threads here. If any threads are still running after this call, |
56 | they will no longer have access to any per-thread data. |
57 | */ |
58 | void SDL_ThreadsQuit(void) |
59 | { |
60 | SDL_mutex *mutex; |
61 | |
62 | mutex = thread_lock; |
63 | thread_lock = NULL; |
64 | if ( mutex != NULL ) { |
65 | SDL_DestroyMutex(mutex); |
66 | } |
67 | } |
68 | |
69 | /* Routines for manipulating the thread list */ |
70 | static void SDL_AddThread(SDL_Thread *thread) |
71 | { |
72 | /* WARNING: |
73 | If the very first threads are created simultaneously, then |
74 | there could be a race condition causing memory corruption. |
75 | In practice, this isn't a problem because by definition there |
76 | is only one thread running the first time this is called. |
77 | */ |
78 | if ( !thread_lock ) { |
79 | if ( SDL_ThreadsInit() < 0 ) { |
80 | return; |
81 | } |
82 | } |
83 | SDL_mutexP(thread_lock); |
84 | |
85 | /* Expand the list of threads, if necessary */ |
86 | #ifdef DEBUG_THREADS |
87 | printf("Adding thread (%d already - %d max)\n", |
88 | SDL_numthreads, SDL_maxthreads); |
89 | #endif |
90 | if ( SDL_numthreads == SDL_maxthreads ) { |
91 | SDL_Thread **threads; |
92 | threads = (SDL_Thread **)SDL_realloc(SDL_Threads, |
93 | (SDL_maxthreads+ARRAY_CHUNKSIZE)*(sizeof *threads)); |
94 | if ( threads == NULL ) { |
95 | SDL_OutOfMemory(); |
96 | goto done; |
97 | } |
98 | SDL_maxthreads += ARRAY_CHUNKSIZE; |
99 | SDL_Threads = threads; |
100 | } |
101 | SDL_Threads[SDL_numthreads++] = thread; |
102 | done: |
103 | SDL_mutexV(thread_lock); |
104 | } |
105 | |
106 | static void SDL_DelThread(SDL_Thread *thread) |
107 | { |
108 | int i; |
109 | |
110 | if ( !thread_lock ) { |
111 | return; |
112 | } |
113 | SDL_mutexP(thread_lock); |
114 | for ( i=0; i<SDL_numthreads; ++i ) { |
115 | if ( thread == SDL_Threads[i] ) { |
116 | break; |
117 | } |
118 | } |
119 | if ( i < SDL_numthreads ) { |
120 | if ( --SDL_numthreads > 0 ) { |
121 | while ( i < SDL_numthreads ) { |
122 | SDL_Threads[i] = SDL_Threads[i+1]; |
123 | ++i; |
124 | } |
125 | } else { |
126 | SDL_maxthreads = 0; |
127 | SDL_free(SDL_Threads); |
128 | SDL_Threads = NULL; |
129 | } |
130 | #ifdef DEBUG_THREADS |
131 | printf("Deleting thread (%d left - %d max)\n", |
132 | SDL_numthreads, SDL_maxthreads); |
133 | #endif |
134 | } |
135 | SDL_mutexV(thread_lock); |
136 | |
137 | #if 0 /* There could be memory corruption if another thread is starting */ |
138 | if ( SDL_Threads == NULL ) { |
139 | SDL_ThreadsQuit(); |
140 | } |
141 | #endif |
142 | } |
143 | |
144 | /* The default (non-thread-safe) global error variable */ |
145 | static SDL_error SDL_global_error; |
146 | |
147 | /* Routine to get the thread-specific error variable */ |
148 | SDL_error *SDL_GetErrBuf(void) |
149 | { |
150 | SDL_error *errbuf; |
151 | |
152 | errbuf = &SDL_global_error; |
153 | if ( SDL_Threads ) { |
154 | int i; |
155 | Uint32 this_thread; |
156 | |
157 | this_thread = SDL_ThreadID(); |
158 | SDL_mutexP(thread_lock); |
159 | for ( i=0; i<SDL_numthreads; ++i ) { |
160 | if ( this_thread == SDL_Threads[i]->threadid ) { |
161 | errbuf = &SDL_Threads[i]->errbuf; |
162 | break; |
163 | } |
164 | } |
165 | SDL_mutexV(thread_lock); |
166 | } |
167 | return(errbuf); |
168 | } |
169 | |
170 | |
171 | /* Arguments and callback to setup and run the user thread function */ |
172 | typedef struct { |
173 | int (SDLCALL *func)(void *); |
174 | void *data; |
175 | SDL_Thread *info; |
176 | SDL_sem *wait; |
177 | } thread_args; |
178 | |
179 | void SDL_RunThread(void *data) |
180 | { |
181 | thread_args *args; |
182 | int (SDLCALL *userfunc)(void *); |
183 | void *userdata; |
184 | int *statusloc; |
185 | |
186 | /* Perform any system-dependent setup |
187 | - this function cannot fail, and cannot use SDL_SetError() |
188 | */ |
189 | SDL_SYS_SetupThread(); |
190 | |
191 | /* Get the thread id */ |
192 | args = (thread_args *)data; |
193 | args->info->threadid = SDL_ThreadID(); |
194 | |
195 | /* Figure out what function to run */ |
196 | userfunc = args->func; |
197 | userdata = args->data; |
198 | statusloc = &args->info->status; |
199 | |
200 | /* Wake up the parent thread */ |
201 | SDL_SemPost(args->wait); |
202 | |
203 | /* Run the function */ |
204 | *statusloc = userfunc(userdata); |
205 | } |
206 | |
207 | #ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD |
208 | #undef SDL_CreateThread |
209 | DECLSPEC SDL_Thread * SDLCALL SDL_CreateThread(int (SDLCALL *fn)(void *), void *data, pfnSDL_CurrentBeginThread pfnBeginThread, pfnSDL_CurrentEndThread pfnEndThread) |
210 | #else |
211 | DECLSPEC SDL_Thread * SDLCALL SDL_CreateThread(int (SDLCALL *fn)(void *), void *data) |
212 | #endif |
213 | { |
214 | SDL_Thread *thread; |
215 | thread_args *args; |
216 | int ret; |
217 | |
218 | /* Allocate memory for the thread info structure */ |
219 | thread = (SDL_Thread *)SDL_malloc(sizeof(*thread)); |
220 | if ( thread == NULL ) { |
221 | SDL_OutOfMemory(); |
222 | return(NULL); |
223 | } |
224 | SDL_memset(thread, 0, (sizeof *thread)); |
225 | thread->status = -1; |
226 | |
227 | /* Set up the arguments for the thread */ |
228 | args = (thread_args *)SDL_malloc(sizeof(*args)); |
229 | if ( args == NULL ) { |
230 | SDL_OutOfMemory(); |
231 | SDL_free(thread); |
232 | return(NULL); |
233 | } |
234 | args->func = fn; |
235 | args->data = data; |
236 | args->info = thread; |
237 | args->wait = SDL_CreateSemaphore(0); |
238 | if ( args->wait == NULL ) { |
239 | SDL_free(thread); |
240 | SDL_free(args); |
241 | return(NULL); |
242 | } |
243 | |
244 | /* Add the thread to the list of available threads */ |
245 | SDL_AddThread(thread); |
246 | |
247 | /* Create the thread and go! */ |
248 | #ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD |
249 | ret = SDL_SYS_CreateThread(thread, args, pfnBeginThread, pfnEndThread); |
250 | #else |
251 | ret = SDL_SYS_CreateThread(thread, args); |
252 | #endif |
253 | if ( ret >= 0 ) { |
254 | /* Wait for the thread function to use arguments */ |
255 | SDL_SemWait(args->wait); |
256 | } else { |
257 | /* Oops, failed. Gotta free everything */ |
258 | SDL_DelThread(thread); |
259 | SDL_free(thread); |
260 | thread = NULL; |
261 | } |
262 | SDL_DestroySemaphore(args->wait); |
263 | SDL_free(args); |
264 | |
265 | /* Everything is running now */ |
266 | return(thread); |
267 | } |
268 | |
269 | void SDL_WaitThread(SDL_Thread *thread, int *status) |
270 | { |
271 | if ( thread ) { |
272 | SDL_SYS_WaitThread(thread); |
273 | if ( status ) { |
274 | *status = thread->status; |
275 | } |
276 | SDL_DelThread(thread); |
277 | SDL_free(thread); |
278 | } |
279 | } |
280 | |
281 | Uint32 SDL_GetThreadID(SDL_Thread *thread) |
282 | { |
283 | Uint32 id; |
284 | |
285 | if ( thread ) { |
286 | id = thread->threadid; |
287 | } else { |
288 | id = SDL_ThreadID(); |
289 | } |
290 | return(id); |
291 | } |
292 | |
293 | void SDL_KillThread(SDL_Thread *thread) |
294 | { |
295 | if ( thread ) { |
296 | SDL_SYS_KillThread(thread); |
297 | SDL_WaitThread(thread, NULL); |
298 | } |
299 | } |
300 | |