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Work toward multithreading support. Currently crashes quickly on a test. (CVS 4253)

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FossilOrigin-Name: 1315bd8e125602275fb718780f9b2730bd37f6ab
This commit is contained in:
drh
2007-08-20 22:48:41 +00:00
parent 7e3c77df0d
commit d677b3d688
23 changed files with 761 additions and 224 deletions
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100
src/os.c
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@@ -74,6 +74,10 @@ int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
}
#endif
/*
** The next group of routines are convenience wrappers around the
** VFS methods.
*/
int sqlite3OsOpen(
sqlite3_vfs *pVfs,
const char *zPath,
@@ -81,9 +85,6 @@ int sqlite3OsOpen(
int flags,
int *pFlagsOut
){
#if defined(SQLITE_TEST) && !defined(SQLITE_OMIT_DISKIO)
return sqlite3CrashFileOpen(pVfs, zPath, pFile, flags, pFlagsOut);
#endif
return pVfs->xOpen(pVfs->pAppData, zPath, pFile, flags, pFlagsOut);
}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
@@ -154,7 +155,96 @@ int sqlite3OsCloseFree(sqlite3_file *pFile){
*/
extern sqlite3_vfs sqlite3DefaultVfs;
sqlite3_vfs *sqlite3_find_vfs(const char *zVfs){
return &sqlite3DefaultVfs;
/*
** The list of all registered VFS implementations.
*/
static sqlite3_vfs *vfsList = &sqlite3DefaultVfs;
/*
** Locate a VFS by name. If no name is given, simply return the
** first VFS on the list.
*/
sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_vfs *pVfs;
sqlite3_mutex_enter(mutex);
for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
if( zVfs==0 ) break;
if( strcmp(zVfs, pVfs->zName)==0 ) break;
}
if( pVfs ){
pVfs->nRef++;
assert( pVfs->nRef==1 || pVfs->vfsMutex!=0 );
assert( pVfs->nRef>1 || pVfs->vfsMutex==0 );
if( pVfs->vfsMutex==0 ){
pVfs->vfsMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
}
}
sqlite3_mutex_leave(mutex);
return pVfs;
}
/*
** Release a VFS once it is no longer needed.
*/
int sqlite3_vfs_release(sqlite3_vfs *pVfs){
sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_mutex_enter(mutex);
assert( pVfs->nRef>0 );
pVfs->nRef--;
if( pVfs->nRef==0 ){
sqlite3_mutex_free(pVfs->vfsMutex);
pVfs->vfsMutex = 0;
}
sqlite3_mutex_leave(mutex);
return SQLITE_OK;
}
/*
** Unlink a VFS from the linked list
*/
static void vfsUnlink(sqlite3_vfs *pVfs){
assert( sqlite3_mutex_held(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER)) );
if( vfsList==pVfs ){
vfsList = pVfs->pNext;
}else{
sqlite3_vfs *p = vfsList;
while( p->pNext && p->pNext!=pVfs ){
p = p->pNext;
}
if( p->pNext==pVfs ){
p->pNext = pVfs->pNext;
}
}
}
/*
** Register a VFS with the system. It is harmless to register the same
** VFS multiple times. The new VFS becomes the default if makeDflt is
** true.
*/
int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_mutex_enter(mutex);
vfsUnlink(pVfs);
if( makeDflt || vfsList==0 ){
pVfs->pNext = vfsList;
vfsList = pVfs;
}else{
pVfs->pNext = vfsList->pNext;
pVfs->pNext = pVfs;
}
sqlite3_mutex_leave(mutex);
return SQLITE_OK;
}
/*
** Unregister a VFS so that it is no longer accessible.
*/
int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_mutex_enter(mutex);
vfsUnlink(pVfs);
sqlite3_mutex_leave(mutex);
return SQLITE_OK;
}