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| 1 /* | |
| 2 ** 2012 July 21 | |
| 3 ** | |
| 4 ** The author disclaims copyright to this source code. In place of | |
| 5 ** a legal notice, here is a blessing: | |
| 6 ** | |
| 7 ** May you do good and not evil. | |
| 8 ** May you find forgiveness for yourself and forgive others. | |
| 9 ** May you share freely, never taking more than you give. | |
| 10 ** | |
| 11 ****************************************************************************** | |
| 12 ** | |
| 13 ** This file presents a simple cross-platform threading interface for | |
| 14 ** use internally by SQLite. | |
| 15 ** | |
| 16 ** A "thread" can be created using sqlite3ThreadCreate(). This thread | |
| 17 ** runs independently of its creator until it is joined using | |
| 18 ** sqlite3ThreadJoin(), at which point it terminates. | |
| 19 ** | |
| 20 ** Threads do not have to be real. It could be that the work of the | |
| 21 ** "thread" is done by the main thread at either the sqlite3ThreadCreate() | |
| 22 ** or sqlite3ThreadJoin() call. This is, in fact, what happens in | |
| 23 ** single threaded systems. Nothing in SQLite requires multiple threads. | |
| 24 ** This interface exists so that applications that want to take advantage | |
| 25 ** of multiple cores can do so, while also allowing applications to stay | |
| 26 ** single-threaded if desired. | |
| 27 */ | |
| 28 #include "sqliteInt.h" | |
| 29 | |
| 30 #if SQLITE_MAX_WORKER_THREADS>0 | |
| 31 | |
| 32 /********************************* Unix Pthreads ****************************/ | |
| 33 #if SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) && SQLITE_THREADSAFE>0 | |
| 34 | |
| 35 #define SQLITE_THREADS_IMPLEMENTED 1 /* Prevent the single-thread code below */ | |
| 36 #include <pthread.h> | |
| 37 | |
| 38 /* A running thread */ | |
| 39 struct SQLiteThread { | |
| 40 pthread_t tid; /* Thread ID */ | |
| 41 int done; /* Set to true when thread finishes */ | |
| 42 void *pOut; /* Result returned by the thread */ | |
| 43 void *(*xTask)(void*); /* The thread routine */ | |
| 44 void *pIn; /* Argument to the thread */ | |
| 45 }; | |
| 46 | |
| 47 /* Create a new thread */ | |
| 48 int sqlite3ThreadCreate( | |
| 49 SQLiteThread **ppThread, /* OUT: Write the thread object here */ | |
| 50 void *(*xTask)(void*), /* Routine to run in a separate thread */ | |
| 51 void *pIn /* Argument passed into xTask() */ | |
| 52 ){ | |
| 53 SQLiteThread *p; | |
| 54 int rc; | |
| 55 | |
| 56 assert( ppThread!=0 ); | |
| 57 assert( xTask!=0 ); | |
| 58 /* This routine is never used in single-threaded mode */ | |
| 59 assert( sqlite3GlobalConfig.bCoreMutex!=0 ); | |
| 60 | |
| 61 *ppThread = 0; | |
| 62 p = sqlite3Malloc(sizeof(*p)); | |
| 63 if( p==0 ) return SQLITE_NOMEM; | |
| 64 memset(p, 0, sizeof(*p)); | |
| 65 p->xTask = xTask; | |
| 66 p->pIn = pIn; | |
| 67 if( sqlite3FaultSim(200) ){ | |
| 68 rc = 1; | |
| 69 }else{ | |
| 70 rc = pthread_create(&p->tid, 0, xTask, pIn); | |
| 71 } | |
| 72 if( rc ){ | |
| 73 p->done = 1; | |
| 74 p->pOut = xTask(pIn); | |
| 75 } | |
| 76 *ppThread = p; | |
| 77 return SQLITE_OK; | |
| 78 } | |
| 79 | |
| 80 /* Get the results of the thread */ | |
| 81 int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ | |
| 82 int rc; | |
| 83 | |
| 84 assert( ppOut!=0 ); | |
| 85 if( NEVER(p==0) ) return SQLITE_NOMEM; | |
| 86 if( p->done ){ | |
| 87 *ppOut = p->pOut; | |
| 88 rc = SQLITE_OK; | |
| 89 }else{ | |
| 90 rc = pthread_join(p->tid, ppOut) ? SQLITE_ERROR : SQLITE_OK; | |
| 91 } | |
| 92 sqlite3_free(p); | |
| 93 return rc; | |
| 94 } | |
| 95 | |
| 96 #endif /* SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) */ | |
| 97 /******************************** End Unix Pthreads *************************/ | |
| 98 | |
| 99 | |
| 100 /********************************* Win32 Threads ****************************/ | |
| 101 #if SQLITE_OS_WIN && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_THREADSAFE>0 | |
| 102 | |
| 103 #define SQLITE_THREADS_IMPLEMENTED 1 /* Prevent the single-thread code below */ | |
| 104 #include <process.h> | |
| 105 | |
| 106 /* A running thread */ | |
| 107 struct SQLiteThread { | |
| 108 void *tid; /* The thread handle */ | |
| 109 unsigned id; /* The thread identifier */ | |
| 110 void *(*xTask)(void*); /* The routine to run as a thread */ | |
| 111 void *pIn; /* Argument to xTask */ | |
| 112 void *pResult; /* Result of xTask */ | |
| 113 }; | |
| 114 | |
| 115 /* Thread procedure Win32 compatibility shim */ | |
| 116 static unsigned __stdcall sqlite3ThreadProc( | |
| 117 void *pArg /* IN: Pointer to the SQLiteThread structure */ | |
| 118 ){ | |
| 119 SQLiteThread *p = (SQLiteThread *)pArg; | |
| 120 | |
| 121 assert( p!=0 ); | |
| 122 #if 0 | |
| 123 /* | |
| 124 ** This assert appears to trigger spuriously on certain | |
| 125 ** versions of Windows, possibly due to _beginthreadex() | |
| 126 ** and/or CreateThread() not fully setting their thread | |
| 127 ** ID parameter before starting the thread. | |
| 128 */ | |
| 129 assert( p->id==GetCurrentThreadId() ); | |
| 130 #endif | |
| 131 assert( p->xTask!=0 ); | |
| 132 p->pResult = p->xTask(p->pIn); | |
| 133 | |
| 134 _endthreadex(0); | |
| 135 return 0; /* NOT REACHED */ | |
| 136 } | |
| 137 | |
| 138 /* Create a new thread */ | |
| 139 int sqlite3ThreadCreate( | |
| 140 SQLiteThread **ppThread, /* OUT: Write the thread object here */ | |
| 141 void *(*xTask)(void*), /* Routine to run in a separate thread */ | |
| 142 void *pIn /* Argument passed into xTask() */ | |
| 143 ){ | |
| 144 SQLiteThread *p; | |
| 145 | |
| 146 assert( ppThread!=0 ); | |
| 147 assert( xTask!=0 ); | |
| 148 *ppThread = 0; | |
| 149 p = sqlite3Malloc(sizeof(*p)); | |
| 150 if( p==0 ) return SQLITE_NOMEM; | |
| 151 if( sqlite3GlobalConfig.bCoreMutex==0 ){ | |
| 152 memset(p, 0, sizeof(*p)); | |
| 153 }else{ | |
| 154 p->xTask = xTask; | |
| 155 p->pIn = pIn; | |
| 156 p->tid = (void*)_beginthreadex(0, 0, sqlite3ThreadProc, p, 0, &p->id); | |
| 157 if( p->tid==0 ){ | |
| 158 memset(p, 0, sizeof(*p)); | |
| 159 } | |
| 160 } | |
| 161 if( p->xTask==0 ){ | |
| 162 p->id = GetCurrentThreadId(); | |
| 163 p->pResult = xTask(pIn); | |
| 164 } | |
| 165 *ppThread = p; | |
| 166 return SQLITE_OK; | |
| 167 } | |
| 168 | |
| 169 DWORD sqlite3Win32Wait(HANDLE hObject); /* os_win.c */ | |
| 170 | |
| 171 /* Get the results of the thread */ | |
| 172 int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ | |
| 173 DWORD rc; | |
| 174 BOOL bRc; | |
| 175 | |
| 176 assert( ppOut!=0 ); | |
| 177 if( NEVER(p==0) ) return SQLITE_NOMEM; | |
| 178 if( p->xTask==0 ){ | |
| 179 assert( p->id==GetCurrentThreadId() ); | |
| 180 rc = WAIT_OBJECT_0; | |
| 181 assert( p->tid==0 ); | |
| 182 }else{ | |
| 183 assert( p->id!=0 && p->id!=GetCurrentThreadId() ); | |
| 184 rc = sqlite3Win32Wait((HANDLE)p->tid); | |
| 185 assert( rc!=WAIT_IO_COMPLETION ); | |
| 186 bRc = CloseHandle((HANDLE)p->tid); | |
| 187 assert( bRc ); | |
| 188 } | |
| 189 if( rc==WAIT_OBJECT_0 ) *ppOut = p->pResult; | |
| 190 sqlite3_free(p); | |
| 191 return (rc==WAIT_OBJECT_0) ? SQLITE_OK : SQLITE_ERROR; | |
| 192 } | |
| 193 | |
| 194 #endif /* SQLITE_OS_WIN && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT */ | |
| 195 /******************************** End Win32 Threads *************************/ | |
| 196 | |
| 197 | |
| 198 /********************************* Single-Threaded **************************/ | |
| 199 #ifndef SQLITE_THREADS_IMPLEMENTED | |
| 200 /* | |
| 201 ** This implementation does not actually create a new thread. It does the | |
| 202 ** work of the thread in the main thread, when either the thread is created | |
| 203 ** or when it is joined | |
| 204 */ | |
| 205 | |
| 206 /* A running thread */ | |
| 207 struct SQLiteThread { | |
| 208 void *(*xTask)(void*); /* The routine to run as a thread */ | |
| 209 void *pIn; /* Argument to xTask */ | |
| 210 void *pResult; /* Result of xTask */ | |
| 211 }; | |
| 212 | |
| 213 /* Create a new thread */ | |
| 214 int sqlite3ThreadCreate( | |
| 215 SQLiteThread **ppThread, /* OUT: Write the thread object here */ | |
| 216 void *(*xTask)(void*), /* Routine to run in a separate thread */ | |
| 217 void *pIn /* Argument passed into xTask() */ | |
| 218 ){ | |
| 219 SQLiteThread *p; | |
| 220 | |
| 221 assert( ppThread!=0 ); | |
| 222 assert( xTask!=0 ); | |
| 223 *ppThread = 0; | |
| 224 p = sqlite3Malloc(sizeof(*p)); | |
| 225 if( p==0 ) return SQLITE_NOMEM; | |
| 226 if( (SQLITE_PTR_TO_INT(p)/17)&1 ){ | |
| 227 p->xTask = xTask; | |
| 228 p->pIn = pIn; | |
| 229 }else{ | |
| 230 p->xTask = 0; | |
| 231 p->pResult = xTask(pIn); | |
| 232 } | |
| 233 *ppThread = p; | |
| 234 return SQLITE_OK; | |
| 235 } | |
| 236 | |
| 237 /* Get the results of the thread */ | |
| 238 int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ | |
| 239 | |
| 240 assert( ppOut!=0 ); | |
| 241 if( NEVER(p==0) ) return SQLITE_NOMEM; | |
| 242 if( p->xTask ){ | |
| 243 *ppOut = p->xTask(p->pIn); | |
| 244 }else{ | |
| 245 *ppOut = p->pResult; | |
| 246 } | |
| 247 sqlite3_free(p); | |
| 248 | |
| 249 #if defined(SQLITE_TEST) | |
| 250 { | |
| 251 void *pTstAlloc = sqlite3Malloc(10); | |
| 252 if (!pTstAlloc) return SQLITE_NOMEM; | |
| 253 sqlite3_free(pTstAlloc); | |
| 254 } | |
| 255 #endif | |
| 256 | |
| 257 return SQLITE_OK; | |
| 258 } | |
| 259 | |
| 260 #endif /* !defined(SQLITE_THREADS_IMPLEMENTED) */ | |
| 261 /****************************** End Single-Threaded *************************/ | |
| 262 #endif /* SQLITE_MAX_WORKER_THREADS>0 */ | |
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Chromium Code Reviews
Issue 2363173002:
[sqlite] Remove obsolete reference version 3.8.7.4. (Closed)
