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Overview
Comment: | Add an implementation of recursive mutexes for unix systems that lack pthreads recursive mutexes (ex: Solaris 2.6). Modern unix systems continue to use the recursive mutexes provided by pthreads. (CVS 4573) |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
f366a776c1b2dda42b4f10fdb8be6602 |
User & Date: | drh 2007-11-28 00:51:35.000 |
Context
2007-11-28
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13:43 | Preset the legacy_file_format pragma to the value of the primary database so that a VACUUM will not unknowingly alter the setting. Ticket #2804. (CVS 4574) (check-in: f731fa6bb3 user: drh tags: trunk) | |
00:51 | Add an implementation of recursive mutexes for unix systems that lack pthreads recursive mutexes (ex: Solaris 2.6). Modern unix systems continue to use the recursive mutexes provided by pthreads. (CVS 4573) (check-in: f366a776c1 user: drh tags: trunk) | |
2007-11-27
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23:36 | Add test cases to verify that the file format is preserved across VACUUM. Ticket #2804. (CVS 4572) (check-in: 57400f50c6 user: drh tags: trunk) | |
Changes
Changes to src/mutex_unix.c.
1 2 3 4 5 6 7 8 9 10 11 12 13 | /* ** 2007 August 28 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains the C functions that implement mutexes for pthreads ** | | > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | /* ** 2007 August 28 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains the C functions that implement mutexes for pthreads ** ** $Id: mutex_unix.c,v 1.3 2007/11/28 00:51:35 drh Exp $ */ #include "sqliteInt.h" /* ** The code in this file is only used if we are compiling threadsafe ** under unix with pthreads. ** ** Note that this implementation requires a version of pthreads that ** supports recursive mutexes. */ #ifdef SQLITE_MUTEX_PTHREADS #include <pthread.h> /* ** Each recursive mutex is an instance of the following structure. */ struct sqlite3_mutex { pthread_mutex_t mutex; /* Mutex controlling the lock */ int id; /* Mutex type */ |
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89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 | { PTHREAD_MUTEX_INITIALIZER, }, }; sqlite3_mutex *p; switch( iType ){ case SQLITE_MUTEX_RECURSIVE: { p = sqlite3MallocZero( sizeof(*p) ); if( p ){ pthread_mutexattr_t recursiveAttr; pthread_mutexattr_init(&recursiveAttr); pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE); pthread_mutex_init(&p->mutex, &recursiveAttr); pthread_mutexattr_destroy(&recursiveAttr); p->id = iType; } break; } case SQLITE_MUTEX_FAST: { p = sqlite3MallocZero( sizeof(*p) ); if( p ){ | > > > > > > > | 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | { PTHREAD_MUTEX_INITIALIZER, }, }; sqlite3_mutex *p; switch( iType ){ case SQLITE_MUTEX_RECURSIVE: { p = sqlite3MallocZero( sizeof(*p) ); if( p ){ #ifdef PTHREAD_MUTEX_RECURSIVE /* Use a recursive mutex if it is available */ pthread_mutexattr_t recursiveAttr; pthread_mutexattr_init(&recursiveAttr); pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE); pthread_mutex_init(&p->mutex, &recursiveAttr); pthread_mutexattr_destroy(&recursiveAttr); #else /* If recursive mutexes are not available, we will have to ** build our own. See below. */ pthread_mutex_init(&p->mutex, 0); #endif p->id = iType; } break; } case SQLITE_MUTEX_FAST: { p = sqlite3MallocZero( sizeof(*p) ); if( p ){ |
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145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 | ** mutex must be exited an equal number of times before another thread ** can enter. If the same thread tries to enter any other kind of mutex ** more than once, the behavior is undefined. */ void sqlite3_mutex_enter(sqlite3_mutex *p){ assert( p ); assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); pthread_mutex_lock(&p->mutex); p->owner = pthread_self(); p->nRef++; #ifdef SQLITE_DEBUG if( p->trace ){ printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); } #endif } int sqlite3_mutex_try(sqlite3_mutex *p){ int rc; assert( p ); assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); if( pthread_mutex_trylock(&p->mutex)==0 ){ p->owner = pthread_self(); p->nRef++; rc = SQLITE_OK; | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | < < | | > > > > > > > > > > > > > > > > | | | > > > > > > > > > > > > > > > > > < | 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 | ** mutex must be exited an equal number of times before another thread ** can enter. If the same thread tries to enter any other kind of mutex ** more than once, the behavior is undefined. */ void sqlite3_mutex_enter(sqlite3_mutex *p){ assert( p ); assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); #ifdef PTHREAD_MUTEX_RECURSIVE /* Use the built-in recursive mutexes if they are available. ** That they are not available on all systems. */ pthread_mutex_lock(&p->mutex); p->owner = pthread_self(); p->nRef++; #else /* If recursive mutexes are not available, then we have to grow ** our own. This implementation assumes that pthread_equal() ** is atomic - that it cannot be deceived into thinking self ** and p->owner are equal if p->owner changes between two values ** that are not equal to self while the comparison is taking place. */ { pthread_t self = pthread_self(); if( p->nRef>0 && pthread_equal(p->owner, self) ){ p->nRef++; }else{ pthread_mutex_lock(&p->mutex); assert( p->nRef==0 ); p->owner = self; p->nRef = 1; } } #endif #ifdef SQLITE_DEBUG if( p->trace ){ printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); } #endif } int sqlite3_mutex_try(sqlite3_mutex *p){ int rc; assert( p ); assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); #ifdef PTHREAD_MUTEX_RECURSIVE /* Use the built-in recursive mutexes if they are available. ** That they are not available on all systems. */ if( pthread_mutex_trylock(&p->mutex)==0 ){ p->owner = pthread_self(); p->nRef++; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } #else /* If recursive mutexes are not available, then we have to grow ** our own. This implementation assumes that pthread_equal() ** is atomic - that it cannot be deceived into thinking self ** and p->owner are equal if p->owner changes between two values ** that are not equal to self while the comparison is taking place. */ { pthread_t self = pthread_self(); if( p->nRef>0 && pthread_equal(p->owner, self) ){ p->nRef++; rc = SQLITE_OK; }else if( pthread_mutex_lock(&p->mutex)==0 ){ assert( p->nRef==0 ); p->owner = self; p->nRef = 1; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } } #endif #ifdef SQLITE_DEBUG if( rc==SQLITE_OK && p->trace ){ printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); } #endif return rc; } /* ** The sqlite3_mutex_leave() routine exits a mutex that was ** previously entered by the same thread. The behavior ** is undefined if the mutex is not currently entered or ** is not currently allocated. SQLite will never do either. */ void sqlite3_mutex_leave(sqlite3_mutex *p){ assert( p ); assert( sqlite3_mutex_held(p) ); p->nRef--; assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE ); #ifdef PTHREAD_RECURSIVE_MUTEX pthread_mutex_unlock(&p->mutex); #else if( p->nRef==0 ){ pthread_mutex_unlock(&p->mutex); } #endif #ifdef SQLITE_DEBUG if( p->trace ){ printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); } #endif } /* ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are ** intended for use only inside assert() statements. On some platforms, ** there might be race conditions that can cause these routines to ** deliver incorrect results. In particular, if pthread_equal() is |
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