diff options
Diffstat (limited to 'src/log.c')
| -rw-r--r-- | src/log.c | 74 |
1 files changed, 51 insertions, 23 deletions
@@ -203,6 +203,14 @@ struct LogSummary { #define LOG_REGION_D 0x08 /* +** Values for the third parameter to logLockRegion(). +*/ +#define LOG_UNLOCK 0 /* Unlock a range of bytes */ +#define LOG_RDLOCK 1 /* Put a SHARED lock on a range of bytes */ +#define LOG_WRLOCK 2 /* Put an EXCLUSIVE lock on a byte-range */ +#define LOG_WRLOCKW 3 /* Block on EXCLUSIVE lock on a byte-range */ + +/* ** A single instance of this structure is allocated as part of each ** connection to a database log. All structures associated with the ** same log file are linked together into a list using LogLock.pNext @@ -225,6 +233,7 @@ struct Log { sqlite3_file *pFd; /* File handle for log file */ int isLocked; /* Non-zero if a snapshot is held open */ int isWriteLocked; /* True if this is the writer connection */ + u32 iCallback; /* Value to pass to log callback (or 0) */ LogSummaryHdr hdr; /* Log summary header for current snapshot */ LogLock lock; /* Lock held by this connection (if any) */ }; @@ -647,29 +656,29 @@ finished: } /* -** Values for the third parameter to logLockRegion(). +** Place, modify or remove a lock on the log-summary file associated +** with pSummary. */ -#define LOG_UNLOCK 0 -#define LOG_RDLOCK 1 -#define LOG_WRLOCK 2 -#define LOG_WRLOCKW 3 - -static int logLockFd(LogSummary *pSummary, int iStart, int nByte, int op){ +static int logLockFd( + LogSummary *pSummary, /* The log-summary object to lock */ + int iStart, /* First byte to lock */ + int nByte, /* Number of bytes to lock */ + int op /* LOG_UNLOCK, RDLOCK, WRLOCK or WRLOCKW */ +){ int aType[4] = { - F_UNLCK, /* LOG_UNLOCK */ - F_RDLCK, /* LOG_RDLOCK */ - F_WRLCK, /* LOG_WRLOCK */ - F_WRLCK /* LOG_WRLOCKW */ + F_UNLCK, /* LOG_UNLOCK */ + F_RDLCK, /* LOG_RDLOCK */ + F_WRLCK, /* LOG_WRLOCK */ + F_WRLCK /* LOG_WRLOCKW */ }; int aOp[4] = { - F_SETLK, /* LOG_UNLOCK */ - F_SETLK, /* LOG_RDLOCK */ - F_SETLK, /* LOG_WRLOCK */ - F_SETLKW /* LOG_WRLOCKW */ + F_SETLK, /* LOG_UNLOCK */ + F_SETLK, /* LOG_RDLOCK */ + F_SETLK, /* LOG_WRLOCK */ + F_SETLKW /* LOG_WRLOCKW */ }; - - struct flock f; /* Locking operation */ - int rc; /* Value returned by fcntl() */ + struct flock f; /* Locking operation */ + int rc; /* Value returned by fcntl() */ assert( ArraySize(aType)==ArraySize(aOp) ); assert( op>=0 && op<ArraySize(aType) ); @@ -816,19 +825,28 @@ static int logLockRegion(Log *pLog, u32 mRegion, int op){ return SQLITE_OK; } +/* +** Lock the DMH region, either with an EXCLUSIVE or SHARED lock. This +** function is never called with LOG_UNLOCK - the only way the DMH region +** is every completely unlocked is by by closing the file descriptor. +*/ static int logLockDMH(LogSummary *pSummary, int eLock){ + assert( sqlite3_mutex_held(pSummary->mutex) ); assert( eLock==LOG_RDLOCK || eLock==LOG_WRLOCK ); return logLockFd(pSummary, LOG_LOCK_DMH, 1, eLock); } +/* +** Lock (or unlock) the MUTEX region. It is always locked using an +** EXCLUSIVE, blocking lock. +*/ static int logLockMutex(LogSummary *pSummary, int eLock){ + assert( sqlite3_mutex_held(pSummary->mutex) ); assert( eLock==LOG_WRLOCKW || eLock==LOG_UNLOCK ); logLockFd(pSummary, LOG_LOCK_MUTEX, 1, eLock); return SQLITE_OK; } - - /* ** This function intializes the connection to the log-summary identified ** by struct pSummary. @@ -880,7 +898,7 @@ static int logSummaryInit( } rc = logLockDMH(pSummary, LOG_RDLOCK); if( rc!=SQLITE_OK ){ - return SQLITE_IOERR; + rc = SQLITE_IOERR; } out: @@ -1461,7 +1479,7 @@ int sqlite3LogRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut){ /* ** Set *pPgno to the size of the database file (or zero, if unknown). */ -void sqlite3LogMaxpgno(Log *pLog, Pgno *pPgno){ +void sqlite3LogDbsize(Log *pLog, Pgno *pPgno){ assert( pLog->isLocked ); *pPgno = pLog->hdr.nPage; } @@ -1646,9 +1664,10 @@ int sqlite3LogFrames( if( isCommit && SQLITE_OK==(rc = logEnterMutex(pLog)) ){ logSummaryWriteHdr(pLog->pSummary, &pLog->hdr); logLeaveMutex(pLog); + pLog->iCallback = iFrame; } - return SQLITE_OK; + return rc; } /* @@ -1698,3 +1717,12 @@ int sqlite3LogCheckpoint( return rc; } +int sqlite3LogCallback(Log *pLog){ + u32 ret = 0; + if( pLog ){ + ret = pLog->iCallback; + pLog->iCallback = 0; + } + return (int)ret; +} + |