| 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 | |