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| 1 /* | |
| 2 ** 2007 August 14 | |
| 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 ** This file contains the C functions that implement mutexes. | |
| 13 ** | |
| 14 ** This file contains code that is common across all mutex implementations. | |
| 15 */ | |
| 16 #include "sqliteInt.h" | |
| 17 | |
| 18 #if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT) | |
| 19 /* | |
| 20 ** For debugging purposes, record when the mutex subsystem is initialized | |
| 21 ** and uninitialized so that we can assert() if there is an attempt to | |
| 22 ** allocate a mutex while the system is uninitialized. | |
| 23 */ | |
| 24 static SQLITE_WSD int mutexIsInit = 0; | |
| 25 #endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */ | |
| 26 | |
| 27 | |
| 28 #ifndef SQLITE_MUTEX_OMIT | |
| 29 /* | |
| 30 ** Initialize the mutex system. | |
| 31 */ | |
| 32 int sqlite3MutexInit(void){ | |
| 33 int rc = SQLITE_OK; | |
| 34 if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){ | |
| 35 /* If the xMutexAlloc method has not been set, then the user did not | |
| 36 ** install a mutex implementation via sqlite3_config() prior to | |
| 37 ** sqlite3_initialize() being called. This block copies pointers to | |
| 38 ** the default implementation into the sqlite3GlobalConfig structure. | |
| 39 */ | |
| 40 sqlite3_mutex_methods const *pFrom; | |
| 41 sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex; | |
| 42 | |
| 43 if( sqlite3GlobalConfig.bCoreMutex ){ | |
| 44 pFrom = sqlite3DefaultMutex(); | |
| 45 }else{ | |
| 46 pFrom = sqlite3NoopMutex(); | |
| 47 } | |
| 48 pTo->xMutexInit = pFrom->xMutexInit; | |
| 49 pTo->xMutexEnd = pFrom->xMutexEnd; | |
| 50 pTo->xMutexFree = pFrom->xMutexFree; | |
| 51 pTo->xMutexEnter = pFrom->xMutexEnter; | |
| 52 pTo->xMutexTry = pFrom->xMutexTry; | |
| 53 pTo->xMutexLeave = pFrom->xMutexLeave; | |
| 54 pTo->xMutexHeld = pFrom->xMutexHeld; | |
| 55 pTo->xMutexNotheld = pFrom->xMutexNotheld; | |
| 56 sqlite3MemoryBarrier(); | |
| 57 pTo->xMutexAlloc = pFrom->xMutexAlloc; | |
| 58 } | |
| 59 assert( sqlite3GlobalConfig.mutex.xMutexInit ); | |
| 60 rc = sqlite3GlobalConfig.mutex.xMutexInit(); | |
| 61 | |
| 62 #ifdef SQLITE_DEBUG | |
| 63 GLOBAL(int, mutexIsInit) = 1; | |
| 64 #endif | |
| 65 | |
| 66 return rc; | |
| 67 } | |
| 68 | |
| 69 /* | |
| 70 ** Shutdown the mutex system. This call frees resources allocated by | |
| 71 ** sqlite3MutexInit(). | |
| 72 */ | |
| 73 int sqlite3MutexEnd(void){ | |
| 74 int rc = SQLITE_OK; | |
| 75 if( sqlite3GlobalConfig.mutex.xMutexEnd ){ | |
| 76 rc = sqlite3GlobalConfig.mutex.xMutexEnd(); | |
| 77 } | |
| 78 | |
| 79 #ifdef SQLITE_DEBUG | |
| 80 GLOBAL(int, mutexIsInit) = 0; | |
| 81 #endif | |
| 82 | |
| 83 return rc; | |
| 84 } | |
| 85 | |
| 86 /* | |
| 87 ** Retrieve a pointer to a static mutex or allocate a new dynamic one. | |
| 88 */ | |
| 89 sqlite3_mutex *sqlite3_mutex_alloc(int id){ | |
| 90 #ifndef SQLITE_OMIT_AUTOINIT | |
| 91 if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0; | |
| 92 if( id>SQLITE_MUTEX_RECURSIVE && sqlite3MutexInit() ) return 0; | |
| 93 #endif | |
| 94 assert( sqlite3GlobalConfig.mutex.xMutexAlloc ); | |
| 95 return sqlite3GlobalConfig.mutex.xMutexAlloc(id); | |
| 96 } | |
| 97 | |
| 98 sqlite3_mutex *sqlite3MutexAlloc(int id){ | |
| 99 if( !sqlite3GlobalConfig.bCoreMutex ){ | |
| 100 return 0; | |
| 101 } | |
| 102 assert( GLOBAL(int, mutexIsInit) ); | |
| 103 assert( sqlite3GlobalConfig.mutex.xMutexAlloc ); | |
| 104 return sqlite3GlobalConfig.mutex.xMutexAlloc(id); | |
| 105 } | |
| 106 | |
| 107 /* | |
| 108 ** Free a dynamic mutex. | |
| 109 */ | |
| 110 void sqlite3_mutex_free(sqlite3_mutex *p){ | |
| 111 if( p ){ | |
| 112 assert( sqlite3GlobalConfig.mutex.xMutexFree ); | |
| 113 sqlite3GlobalConfig.mutex.xMutexFree(p); | |
| 114 } | |
| 115 } | |
| 116 | |
| 117 /* | |
| 118 ** Obtain the mutex p. If some other thread already has the mutex, block | |
| 119 ** until it can be obtained. | |
| 120 */ | |
| 121 void sqlite3_mutex_enter(sqlite3_mutex *p){ | |
| 122 if( p ){ | |
| 123 assert( sqlite3GlobalConfig.mutex.xMutexEnter ); | |
| 124 sqlite3GlobalConfig.mutex.xMutexEnter(p); | |
| 125 } | |
| 126 } | |
| 127 | |
| 128 /* | |
| 129 ** Obtain the mutex p. If successful, return SQLITE_OK. Otherwise, if another | |
| 130 ** thread holds the mutex and it cannot be obtained, return SQLITE_BUSY. | |
| 131 */ | |
| 132 int sqlite3_mutex_try(sqlite3_mutex *p){ | |
| 133 int rc = SQLITE_OK; | |
| 134 if( p ){ | |
| 135 assert( sqlite3GlobalConfig.mutex.xMutexTry ); | |
| 136 return sqlite3GlobalConfig.mutex.xMutexTry(p); | |
| 137 } | |
| 138 return rc; | |
| 139 } | |
| 140 | |
| 141 /* | |
| 142 ** The sqlite3_mutex_leave() routine exits a mutex that was previously | |
| 143 ** entered by the same thread. The behavior is undefined if the mutex | |
| 144 ** is not currently entered. If a NULL pointer is passed as an argument | |
| 145 ** this function is a no-op. | |
| 146 */ | |
| 147 void sqlite3_mutex_leave(sqlite3_mutex *p){ | |
| 148 if( p ){ | |
| 149 assert( sqlite3GlobalConfig.mutex.xMutexLeave ); | |
| 150 sqlite3GlobalConfig.mutex.xMutexLeave(p); | |
| 151 } | |
| 152 } | |
| 153 | |
| 154 #ifndef NDEBUG | |
| 155 /* | |
| 156 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are | |
| 157 ** intended for use inside assert() statements. | |
| 158 */ | |
| 159 int sqlite3_mutex_held(sqlite3_mutex *p){ | |
| 160 assert( p==0 || sqlite3GlobalConfig.mutex.xMutexHeld ); | |
| 161 return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p); | |
| 162 } | |
| 163 int sqlite3_mutex_notheld(sqlite3_mutex *p){ | |
| 164 assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld ); | |
| 165 return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p); | |
| 166 } | |
| 167 #endif | |
| 168 | |
| 169 #endif /* !defined(SQLITE_MUTEX_OMIT) */ | |
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Chromium Code Reviews
Issue 2846743003:
[sql] Remove SQLite 3.10.2 reference directory. (Closed)
