/*
** Shared-memory methods are all pass-thrus.
*/
static int devsymShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
devsym_file *p = (devsym_file *)pFile;
return sqlite3OsShmLock(p->pReal, ofst, n, flags);
}
/*
** Pass-throughs for WAL support.
*/
static int cfShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
return sqlite3OsShmLock(((CrashFile*)pFile)->pRealFile, ofst, n, flags);
}
static int tvfsShmLock(
sqlite3_file *pFile,
int ofst,
int n,
int flags
){
int rc = SQLITE_OK;
TestvfsFd *pFd = tvfsGetFd(pFile);
Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);
int nLock;
char zLock[80];
if( p->isFullshm ){
return sqlite3OsShmLock(pFd->pReal, ofst, n, flags);
}
if( p->pScript && p->mask&TESTVFS_SHMLOCK_MASK ){
sqlite3_snprintf(sizeof(zLock), zLock, "%d %d", ofst, n);
nLock = (int)strlen(zLock);
if( flags & SQLITE_SHM_LOCK ){
strcpy(&zLock[nLock], " lock");
}else{
strcpy(&zLock[nLock], " unlock");
}
nLock += (int)strlen(&zLock[nLock]);
if( flags & SQLITE_SHM_SHARED ){
strcpy(&zLock[nLock], " shared");
}else{
strcpy(&zLock[nLock], " exclusive");
}
tvfsExecTcl(p, "xShmLock",
Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId,
Tcl_NewStringObj(zLock, -1), 0
);
tvfsResultCode(p, &rc);
}
if( rc==SQLITE_OK && p->mask&TESTVFS_SHMLOCK_MASK && tvfsInjectIoerr(p) ){
rc = SQLITE_IOERR;
}
if( rc==SQLITE_OK ){
int isLock = (flags & SQLITE_SHM_LOCK);
int isExcl = (flags & SQLITE_SHM_EXCLUSIVE);
u32 mask = (((1<<n)-1) << ofst);
if( isLock ){
TestvfsFd *p2;
for(p2=pFd->pShm->pFile; p2; p2=p2->pNext){
if( p2==pFd ) continue;
if( (p2->excllock&mask) || (isExcl && p2->sharedlock&mask) ){
rc = SQLITE_BUSY;
break;
}
}
if( rc==SQLITE_OK ){
if( isExcl ) pFd->excllock |= mask;
if( !isExcl ) pFd->sharedlock |= mask;
}
}else{
if( isExcl ) pFd->excllock &= (~mask);
if( !isExcl ) pFd->sharedlock &= (~mask);
}
}
return rc;
}