winFile *pFile = (winFile*)id;
assert( id!=0 );
- OSTRACE2("CLOSE %d\n", pFile->h);
do{
rc = CloseHandle(pFile->h);
}while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
free(pFile->zDeleteOnClose);
}
#endif
+ OSTRACE(("CLOSE %d %s\n", pFile->h, rc ? "ok" : "failed"));
OpenCounter(-1);
return rc ? SQLITE_OK : SQLITE_IOERR;
}
static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
LONG upperBits = (LONG)((nByte>>32) & 0x7fffffff);
LONG lowerBits = (LONG)(nByte & 0xffffffff);
- DWORD rc;
+ DWORD dwRet;
winFile *pFile = (winFile*)id;
DWORD error;
+ int rc = SQLITE_OK;
assert( id!=0 );
- OSTRACE3("TRUNCATE %d %lld\n", pFile->h, nByte);
SimulateIOError(return SQLITE_IOERR_TRUNCATE);
- rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
- if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
+ dwRet = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+ if( dwRet==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
pFile->lastErrno = error;
- return SQLITE_IOERR_TRUNCATE;
- }
+ rc = SQLITE_IOERR_TRUNCATE;
/* SetEndOfFile will fail if nByte is negative */
- if( !SetEndOfFile(pFile->h) ){
+ }else if( !SetEndOfFile(pFile->h) ){
pFile->lastErrno = GetLastError();
- return SQLITE_IOERR_TRUNCATE;
+ rc = SQLITE_IOERR_TRUNCATE;
}
- return SQLITE_OK;
+ OSTRACE(("TRUNCATE %d %lld %s\n", pFile->h, nByte, rc==SQLITE_OK ? "ok" : "failed"));
+ return rc;
}
#ifdef SQLITE_TEST
assert( id!=0 );
UNUSED_PARAMETER(pVfs);
+ pFile->h = INVALID_HANDLE_VALUE;
+
/* If the second argument to this function is NULL, generate a
** temporary file name to use
*/
);
#endif
}
+ OSTRACE4("OPEN %d %s 0x%lx\n", h, zName, dwDesiredAccess);
if( h==INVALID_HANDLE_VALUE ){
free(zConverted);
if( flags & SQLITE_OPEN_READWRITE ){
#endif
}
free(zConverted);
- OSTRACE2("DELETE \"%s\"\n", zFilename);
+ OSTRACE(("DELETE \"%s\" %s\n", zFilename, ( (rc == INVALID_FILE_ATTRIBUTES)
+ && (error == ERROR_FILE_NOT_FOUND)) ? "ok" : "failed" ));
return ( (rc == INVALID_FILE_ATTRIBUTES)
&& (error == ERROR_FILE_NOT_FOUND)) ? SQLITE_OK : SQLITE_IOERR_DELETE;
}
}
/*
-** The following variable, if set to a non-zero value, becomes the result
-** returned from sqlite3OsCurrentTime(). This is used for testing.
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
*/
#ifdef SQLITE_TEST
-int sqlite3_current_time = 0;
+int sqlite3_current_time = 0; /* Fake system time in seconds since 1970. */
#endif
/*
-** Find the current time (in Universal Coordinated Time). Write the
-** current time and date as a Julian Day number into *prNow and
-** return 0. Return 1 if the time and date cannot be found.
+** Find the current time (in Universal Coordinated Time). Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000. In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return 0. Return 1 if the time and date cannot be found.
*/
-int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
- FILETIME ft;
+static int winCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *piNow){
/* FILETIME structure is a 64-bit value representing the number of
100-nanosecond intervals since January 1, 1601 (= JD 2305813.5).
*/
- sqlite3_int64 timeW; /* Whole days */
- sqlite3_int64 timeF; /* Fractional Days */
-
- /* Number of 100-nanosecond intervals in a single day */
- static const sqlite3_int64 ntuPerDay =
- 10000000*(sqlite3_int64)86400;
-
- /* Number of 100-nanosecond intervals in half of a day */
- static const sqlite3_int64 ntuPerHalfDay =
- 10000000*(sqlite3_int64)43200;
-
+ FILETIME ft;
+ static const sqlite3_int64 winFiletimeEpoch = 23058135*(sqlite3_int64)8640000;
+#ifdef SQLITE_TEST
+ static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+#endif
/* 2^32 - to avoid use of LL and warnings in gcc */
static const sqlite3_int64 max32BitValue =
(sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 + (sqlite3_int64)294967296;
#else
GetSystemTimeAsFileTime( &ft );
#endif
- UNUSED_PARAMETER(pVfs);
- timeW = (((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) + (sqlite3_int64)ft.dwLowDateTime;
- timeF = timeW % ntuPerDay; /* fractional days (100-nanoseconds) */
- timeW = timeW / ntuPerDay; /* whole days */
- timeW = timeW + 2305813; /* add whole days (from 2305813.5) */
- timeF = timeF + ntuPerHalfDay; /* add half a day (from 2305813.5) */
- timeW = timeW + (timeF/ntuPerDay); /* add whole day if half day made one */
- timeF = timeF % ntuPerDay; /* compute new fractional days */
- *prNow = (double)timeW + ((double)timeF / (double)ntuPerDay);
+
+ *piNow = winFiletimeEpoch +
+ ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) +
+ (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)1000;
+
#ifdef SQLITE_TEST
if( sqlite3_current_time ){
- *prNow = ((double)sqlite3_current_time + (double)43200) / (double)86400 + (double)2440587;
+ *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
}
#endif
+ UNUSED_PARAMETER(pVfs);
return 0;
}
+/*
+** Find the current time (in Universal Coordinated Time). Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0. Return 1 if the time and date cannot be found.
+*/
+int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+ int rc;
+ sqlite3_int64 i;
+ rc = winCurrentTimeInt64(pVfs, &i);
+ if( !rc ){
+ *prNow = i/86400000.0;
+ }
+ return rc;
+}
+
/*
** The idea is that this function works like a combination of
** GetLastError() and FormatMessage() on windows (or errno and
return getLastErrorMsg(nBuf, zBuf);
}
+#ifndef SQLITE_OMIT_WAL
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the winLockInfo objects used by
+** this file, all of which may be shared by multiple threads.
+**
+** Function winShmMutexHeld() is used to assert() that the global mutex
+** is held when required. This function is only used as part of assert()
+** statements. e.g.
+**
+** winShmEnterMutex()
+** assert( winShmMutexHeld() );
+** winEnterLeave()
+*/
+static void winShmEnterMutex(void){
+ sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+static void winShmLeaveMutex(void){
+ sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+#ifdef SQLITE_DEBUG
+static int winShmMutexHeld(void) {
+ return sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
+}
+#endif
+
+/* Forward reference */
+typedef struct winShm winShm;
+typedef struct winShmFile winShmFile;
+
+/*
+** Object used to represent a single file opened and mmapped to provide
+** shared memory. When multiple threads all reference the same
+** log-summary, each thread has its own winFile object, but they all
+** point to a single instance of this object. In other words, each
+** log-summary is opened only once per process.
+**
+** winShmMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+** nRef
+** pNext
+**
+** The following fields are read-only after the object is created:
+**
+** fid
+** zFilename
+**
+** Either winShmFile.mutex must be held or winShmFile.nRef==0 and
+** winShmMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+** To avoid deadlocks, mutex and mutexBuf are always released in the
+** reverse order that they are acquired. mutexBuf is always acquired
+** first and released last. This invariant is check by asserting
+** sqlite3_mutex_notheld() on mutex whenever mutexBuf is acquired or
+** released.
+*/
+struct winShmFile {
+ sqlite3_mutex *mutex; /* Mutex to access this object */
+ sqlite3_mutex *mutexBuf; /* Mutex to access zBuf[] */
+ char *zFilename; /* Name of the file */
+ winFile hFile; /* File handle from winOpen */
+ HANDLE hMap; /* File handle from CreateFileMapping */
+ DWORD lastErrno; /* The Windows errno from the last I/O error */
+ int szMap; /* Size of the mapping of file into memory */
+ char *pMMapBuf; /* Where currently mmapped(). NULL if unmapped */
+ int nRef; /* Number of winShm objects pointing to this */
+ winShm *pFirst; /* All winShm objects pointing to this */
+ winShmFile *pNext; /* Next in list of all winShmFile objects */
+#ifdef SQLITE_DEBUG
+ u8 exclMask; /* Mask of exclusive locks held */
+ u8 sharedMask; /* Mask of shared locks held */
+ u8 nextShmId; /* Next available winShm.id value */
+#endif
+};
+
+/*
+** A global array of all winShmFile objects.
+**
+** The winShmMutexHeld() must be true while reading or writing this list.
+*/
+static winShmFile *winShmFileList = 0;
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** winShm.pFile->mutex must be held while reading or writing the
+** winShm.pNext and winShm.locks[] elements.
+**
+** The winShm.pFile element is initialized when the object is created
+** and is read-only thereafter.
+*/
+struct winShm {
+ winShmFile *pFile; /* The underlying winShmFile object */
+ winShm *pNext; /* Next winShm with the same winShmFile */
+ u8 lockState; /* Current lock state */
+ u8 hasMutex; /* True if holding the winShmFile mutex */
+ u8 hasMutexBuf; /* True if holding pFile->mutexBuf */
+ u8 sharedMask; /* Mask of shared locks held */
+ u8 exclMask; /* Mask of exclusive locks held */
+#ifdef SQLITE_DEBUG
+ u8 id; /* Id of this connection with its winShmFile */
+#endif
+};
+
+/*
+** Size increment by which shared memory grows
+*/
+#define SQLITE_WIN_SHM_INCR 4096
+
+/*
+** Constants used for locking
+*/
+#define WIN_SHM_BASE 32 /* Byte offset of the first lock byte */
+#define WIN_SHM_DMS 0x01 /* Mask for Dead-Man-Switch lock */
+#define WIN_SHM_A 0x10 /* Mask for region locks... */
+#define WIN_SHM_B 0x20
+#define WIN_SHM_C 0x40
+#define WIN_SHM_D 0x80
+
+#ifdef SQLITE_DEBUG
+/*
+** Return a pointer to a nul-terminated string in static memory that
+** describes a locking mask. The string is of the form "MSABCD" with
+** each character representing a lock. "M" for MUTEX, "S" for DMS,
+** and "A" through "D" for the region locks. If a lock is held, the
+** letter is shown. If the lock is not held, the letter is converted
+** to ".".
+**
+** This routine is for debugging purposes only and does not appear
+** in a production build.
+*/
+static const char *winShmLockString(u8 mask){
+ static char zBuf[48];
+ static int iBuf = 0;
+ char *z;
+
+ z = &zBuf[iBuf];
+ iBuf += 8;
+ if( iBuf>=sizeof(zBuf) ) iBuf = 0;
+
+ z[0] = (mask & WIN_SHM_DMS) ? 'S' : '.';
+ z[1] = (mask & WIN_SHM_A) ? 'A' : '.';
+ z[2] = (mask & WIN_SHM_B) ? 'B' : '.';
+ z[3] = (mask & WIN_SHM_C) ? 'C' : '.';
+ z[4] = (mask & WIN_SHM_D) ? 'D' : '.';
+ z[5] = 0;
+ return z;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Apply posix advisory locks for all bytes identified in lockMask.
+**
+** lockMask might contain multiple bits but all bits are guaranteed
+** to be contiguous.
+**
+** Locks block if the mask is exactly WIN_SHM_C and are non-blocking
+** otherwise.
+*/
+#define _SHM_UNLCK 1
+#define _SHM_RDLCK 2
+#define _SHM_WRLCK 3
+static int winShmSystemLock(
+ winShmFile *pFile, /* Apply locks to this open shared-memory segment */
+ int lockType, /* _SHM_UNLCK, _SHM_RDLCK, or _SHM_WRLCK */
+ u8 lockMask /* Which bytes to lock or unlock */
+){
+ OVERLAPPED ovlp;
+ DWORD dwFlags;
+ int nBytes; /* Number of bytes to lock */
+ int i; /* Offset into the locking byte range */
+ int rc = 0; /* Result code form Lock/UnlockFileEx() */
+ u8 mask; /* Mask of bits in lockMask */
+
+ /* Access to the winShmFile object is serialized by the caller */
+ assert( sqlite3_mutex_held(pFile->mutex) || pFile->nRef==0 );
+
+ /* Initialize the locking parameters */
+ if( lockMask==WIN_SHM_C && lockType!=_SHM_UNLCK ){
+ dwFlags = 0;
+ OSTRACE(("SHM-LOCK requesting blocking lock %s\n", winShmLockString(lockMask)));
+ }else{
+ dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
+ OSTRACE(("SHM-LOCK requesting %s %s\n", lockType!=_SHM_UNLCK ? "unlock" : "lock", winShmLockString(lockMask)));
+ }
+ if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
+
+ /* Find the first bit in lockMask that is set */
+ for(i=0, mask=0x01; mask!=0 && (lockMask&mask)==0; mask <<= 1, i++){}
+ assert( mask!=0 );
+ memset(&ovlp, 0, sizeof(OVERLAPPED));
+ ovlp.Offset = i+WIN_SHM_BASE;
+ ovlp.OffsetHigh = 0;
+ nBytes = 1;
+
+ /* Extend the locking range for each additional bit that is set */
+ mask <<= 1;
+ while( mask!=0 && (lockMask & mask)!=0 ){
+ nBytes++;
+ mask <<= 1;
+ }
+
+ /* Verify that all bits set in lockMask are contiguous */
+ assert( mask==0 || (lockMask & ~(mask | (mask-1)))==0 );
+
+ /* Release/Acquire the system-level lock */
+ if( lockType==_SHM_UNLCK ){
+ for(i=0; i<nBytes; i++, ovlp.Offset++){
+ rc = UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
+ if( !rc ) break;
+ }
+ if( !rc ){
+ OSTRACE(("SHM-LOCK UnlockFileEx ERROR %d - 0x%08lx\n", rc, GetLastError()));
+ /* continue to release individual byte locks (if any) */
+ for(; i<nBytes; i++, ovlp.Offset++){
+ UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
+ }
+ }
+ }else{
+ /* release old individual byte locks (if any). */
+ for(i=0; i<nBytes; i++, ovlp.Offset++){
+ UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
+ }
+ ovlp.Offset-=nBytes;
+ /* set new individual byte locks */
+ for(i=0; i<(int)nBytes; i++, ovlp.Offset++){
+ rc = LockFileEx(pFile->hFile.h, dwFlags, 0, 1, 0, &ovlp);
+ if( !rc ) break;
+ }
+ if( !rc ){
+ OSTRACE(("SHM-LOCK LockFileEx ERROR %d - 0x%08lx\n", rc, GetLastError()));
+ /* release individual byte locks (if any) */
+ ovlp.Offset-=i;
+ for(i=0; i<nBytes; i++, ovlp.Offset++){
+ UnlockFileEx(pFile->hFile.h, 0, 1, 0, &ovlp);
+ }
+ }
+ }
+ rc = (rc!=0) ? SQLITE_OK : SQLITE_BUSY;
+
+ /* Update the global lock state and do debug tracing */
+#ifdef SQLITE_DEBUG
+ OSTRACE(("SHM-LOCK %d ", pFile->hFile.h));
+ if( rc==SQLITE_OK ){
+ if( lockType==_SHM_UNLCK ){
+ OSTRACE(("unlock ok"));
+ pFile->exclMask &= ~lockMask;
+ pFile->sharedMask &= ~lockMask;
+ }else if( lockType==_SHM_RDLCK ){
+ OSTRACE(("read-lock ok"));
+ pFile->exclMask &= ~lockMask;
+ pFile->sharedMask |= lockMask;
+ }else{
+ assert( lockType==_SHM_WRLCK );
+ OSTRACE(("write-lock ok"));
+ pFile->exclMask |= lockMask;
+ pFile->sharedMask &= ~lockMask;
+ }
+ }else{
+ if( lockType==_SHM_UNLCK ){
+ OSTRACE(("unlock failed"));
+ }else if( lockType==_SHM_RDLCK ){
+ OSTRACE(("read-lock failed"));
+ }else{
+ assert( lockType==_SHM_WRLCK );
+ OSTRACE(("write-lock failed"));
+ }
+ }
+ OSTRACE((" - change requested %s - afterwards %s:%s\n",
+ winShmLockString(lockMask),
+ winShmLockString(pFile->sharedMask),
+ winShmLockString(pFile->exclMask)));
+#endif
+
+ return rc;
+}
+
+/*
+** For connection p, unlock all of the locks identified by the unlockMask
+** parameter.
+*/
+static int winShmUnlock(
+ winShmFile *pFile, /* The underlying shared-memory file */
+ winShm *p, /* The connection to be unlocked */
+ u8 unlockMask /* Mask of locks to be unlocked */
+){
+ int rc; /* Result code */
+ winShm *pX; /* For looping over all sibling connections */
+ u8 allMask; /* Union of locks held by connections other than "p" */
+
+ /* Access to the winShmFile object is serialized by the caller */
+ assert( sqlite3_mutex_held(pFile->mutex) );
+
+ /* don't attempt to unlock anything we don't have locks for */
+ if( (unlockMask & (p->exclMask|p->sharedMask)) != unlockMask ){
+ OSTRACE(("SHM-UNLOCKING more than we have locked - requested %s - have %s\n",
+ winShmLockString(unlockMask),
+ winShmLockString(p->exclMask|p->sharedMask)));
+ unlockMask &= (p->exclMask|p->sharedMask);
+ }
+
+ /* Compute locks held by sibling connections */
+ allMask = 0;
+ for(pX=pFile->pFirst; pX; pX=pX->pNext){
+ if( pX==p ) continue;
+ assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
+ allMask |= pX->sharedMask;
+ }
+
+ /* Unlock the system-level locks */
+ if( (unlockMask & allMask)!=unlockMask ){
+ rc = winShmSystemLock(pFile, _SHM_UNLCK, unlockMask & ~allMask);
+ }else{
+ rc = SQLITE_OK;
+ }
+
+ /* Undo the local locks */
+ if( rc==SQLITE_OK ){
+ p->exclMask &= ~unlockMask;
+ p->sharedMask &= ~unlockMask;
+ }
+ return rc;
+}
+
+/*
+** Get reader locks for connection p on all locks in the readMask parameter.
+*/
+static int winShmSharedLock(
+ winShmFile *pFile, /* The underlying shared-memory file */
+ winShm *p, /* The connection to get the shared locks */
+ u8 readMask /* Mask of shared locks to be acquired */
+){
+ int rc; /* Result code */
+ winShm *pX; /* For looping over all sibling connections */
+ u8 allShared; /* Union of locks held by connections other than "p" */
+
+ /* Access to the winShmFile object is serialized by the caller */
+ assert( sqlite3_mutex_held(pFile->mutex) );
+
+ /* Find out which shared locks are already held by sibling connections.
+ ** If any sibling already holds an exclusive lock, go ahead and return
+ ** SQLITE_BUSY.
+ */
+ allShared = 0;
+ for(pX=pFile->pFirst; pX; pX=pX->pNext){
+ if( pX==p ) continue;
+ if( (pX->exclMask & readMask)!=0 ) return SQLITE_BUSY;
+ allShared |= pX->sharedMask;
+ }
+
+ /* Get shared locks at the system level, if necessary */
+ if( (~allShared) & readMask ){
+ rc = winShmSystemLock(pFile, _SHM_RDLCK, readMask);
+ }else{
+ rc = SQLITE_OK;
+ }
+
+ /* Get the local shared locks */
+ if( rc==SQLITE_OK ){
+ p->sharedMask |= readMask;
+ }
+ return rc;
+}
+
+/*
+** For connection p, get an exclusive lock on all locks identified in
+** the writeMask parameter.
+*/
+static int winShmExclusiveLock(
+ winShmFile *pFile, /* The underlying shared-memory file */
+ winShm *p, /* The connection to get the exclusive locks */
+ u8 writeMask /* Mask of exclusive locks to be acquired */
+){
+ int rc; /* Result code */
+ winShm *pX; /* For looping over all sibling connections */
+
+ /* Access to the winShmFile object is serialized by the caller */
+ assert( sqlite3_mutex_held(pFile->mutex) );
+
+ /* Make sure no sibling connections hold locks that will block this
+ ** lock. If any do, return SQLITE_BUSY right away.
+ */
+ for(pX=pFile->pFirst; pX; pX=pX->pNext){
+ if( pX==p ) continue;
+ if( (pX->exclMask & writeMask)!=0 ) return SQLITE_BUSY;
+ if( (pX->sharedMask & writeMask)!=0 ) return SQLITE_BUSY;
+ }
+
+ /* Get the exclusive locks at the system level. Then if successful
+ ** also mark the local connection as being locked.
+ */
+ rc = winShmSystemLock(pFile, _SHM_WRLCK, writeMask);
+ if( rc==SQLITE_OK ){
+ p->sharedMask &= ~writeMask;
+ p->exclMask |= writeMask;
+ }
+ return rc;
+}
+
+/*
+** Purge the winShmFileList list of all entries with winShmFile.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void winShmPurge(void){
+ winShmFile **pp;
+ winShmFile *p;
+ assert( winShmMutexHeld() );
+ pp = &winShmFileList;
+ while( (p = *pp)!=0 ){
+ if( p->nRef==0 ){
+ if( p->mutex ) sqlite3_mutex_free(p->mutex);
+ if( p->mutexBuf ) sqlite3_mutex_free(p->mutexBuf);
+ if( p->pMMapBuf ){
+ UnmapViewOfFile(p->pMMapBuf);
+ }
+ if( INVALID_HANDLE_VALUE != p->hMap ){
+ CloseHandle(p->hMap);
+ }
+ if( p->hFile.h != INVALID_HANDLE_VALUE ) {
+ winClose((sqlite3_file *)&p->hFile);
+ }
+ *pp = p->pNext;
+ sqlite3_free(p);
+ }else{
+ pp = &p->pNext;
+ }
+ }
+}
+
+/*
+** Open a shared-memory area. This particular implementation uses
+** mmapped files.
+**
+** zName is a filename used to identify the shared-memory area. The
+** implementation does not (and perhaps should not) use this name
+** directly, but rather use it as a template for finding an appropriate
+** name for the shared-memory storage. In this implementation, the
+** string "-index" is appended to zName and used as the name of the
+** mmapped file.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+*/
+static int winShmOpen(
+ sqlite3_vfs *pVfs, /* The VFS */
+ const char *zName, /* Name of the corresponding database file */
+ sqlite3_shm **pShm /* Write the winShm object created here */
+){
+ struct winShm *p = 0; /* The connection to be opened */
+ struct winShmFile *pFile = 0; /* The underlying mmapped file */
+ int rc; /* Result code */
+ struct winShmFile *pNew; /* Newly allocated pFile */
+ int nName; /* Size of zName in bytes */
+
+ /* Allocate space for the new sqlite3_shm object. Also speculatively
+ ** allocate space for a new winShmFile and filename.
+ */
+ p = sqlite3_malloc( sizeof(*p) );
+ if( p==0 ) return SQLITE_NOMEM;
+ memset(p, 0, sizeof(*p));
+ nName = strlen(zName);
+ pNew = sqlite3_malloc( sizeof(*pFile) + nName + 15 );
+ if( pNew==0 ){
+ sqlite3_free(p);
+ return SQLITE_NOMEM;
+ }
+ memset(pNew, 0, sizeof(*pNew));
+ pNew->zFilename = (char*)&pNew[1];
+ sqlite3_snprintf(nName+11, pNew->zFilename, "%s-wal-index", zName);
+
+ /* Look to see if there is an existing winShmFile that can be used.
+ ** If no matching winShmFile currently exists, create a new one.
+ */
+ winShmEnterMutex();
+ for(pFile = winShmFileList; pFile; pFile=pFile->pNext){
+ /* TBD need to come up with better match here. Perhaps
+ ** use winFullPathname() or FILE_ID_BOTH_DIR_INFO Structure.
+ */
+ if( strcmp(pFile->zFilename, pNew->zFilename)==0 ) break;
+ }
+ if( pFile ){
+ sqlite3_free(pNew);
+ }else{
+ pFile = pNew;
+ pNew = 0;
+ pFile->pMMapBuf = NULL;
+ pFile->hMap = INVALID_HANDLE_VALUE;
+ ((winFile*)(&pFile->hFile))->h = INVALID_HANDLE_VALUE;
+ pFile->pNext = winShmFileList;
+ winShmFileList = pFile;
+
+ pFile->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+ if( pFile->mutex==0 ){
+ rc = SQLITE_NOMEM;
+ goto shm_open_err;
+ }
+ pFile->mutexBuf = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+ if( pFile->mutexBuf==0 ){
+ rc = SQLITE_NOMEM;
+ goto shm_open_err;
+ }
+
+ rc = winOpen(pVfs,
+ pFile->zFilename, /* Name of the file (UTF-8) */
+ (sqlite3_file *)&pFile->hFile, /* Write the SQLite file handle here */
+ SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Open mode flags */
+ 0);
+ if( SQLITE_OK!=rc ){
+ rc = SQLITE_CANTOPEN_BKPT;
+ goto shm_open_err;
+ }
+
+ /* Check to see if another process is holding the dead-man switch.
+ ** If not, truncate the file to zero length.
+ */
+ if( winShmSystemLock(pFile, _SHM_WRLCK, WIN_SHM_DMS)==SQLITE_OK ){
+ rc = winTruncate((sqlite3_file *)&pFile->hFile, 0);
+ }
+ if( rc==SQLITE_OK ){
+ rc = winShmSystemLock(pFile, _SHM_RDLCK, WIN_SHM_DMS);
+ }
+ if( rc ) goto shm_open_err;
+ }
+
+ /* Make the new connection a child of the winShmFile */
+ p->pFile = pFile;
+ p->pNext = pFile->pFirst;
+#ifdef SQLITE_DEBUG
+ p->id = pFile->nextShmId++;
+#endif
+ pFile->pFirst = p;
+ pFile->nRef++;
+ *pShm = (sqlite3_shm*)p;
+ winShmLeaveMutex();
+ return SQLITE_OK;
+
+ /* Jump here on any error */
+shm_open_err:
+ winShmSystemLock(pFile, _SHM_UNLCK, WIN_SHM_DMS);
+ winShmPurge(); /* This call frees pFile if required */
+ sqlite3_free(p);
+ sqlite3_free(pNew);
+ *pShm = 0;
+ winShmLeaveMutex();
+ return rc;
+}
+
+/*
+** Close a connection to shared-memory. Delete the underlying
+** storage if deleteFlag is true.
+*/
+static int winShmClose(
+ sqlite3_vfs *pVfs, /* The VFS */
+ sqlite3_shm *pSharedMem, /* The shared-memory to be closed */
+ int deleteFlag /* Delete after closing if true */
+){
+ winShm *p; /* The connection to be closed */
+ winShmFile *pFile; /* The underlying shared-memory file */
+ winShm **pp; /* For looping over sibling connections */
+
+ UNUSED_PARAMETER(pVfs);
+ if( pSharedMem==0 ) return SQLITE_OK;
+ p = (struct winShm*)pSharedMem;
+ pFile = p->pFile;
+
+ /* Verify that the connection being closed holds no locks */
+ assert( p->exclMask==0 );
+ assert( p->sharedMask==0 );
+
+ /* Remove connection p from the set of connections associated with pFile */
+ sqlite3_mutex_enter(pFile->mutex);
+ for(pp=&pFile->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+ *pp = p->pNext;
+
+ /* Free the connection p */
+ sqlite3_free(p);
+ sqlite3_mutex_leave(pFile->mutex);
+
+ /* If pFile->nRef has reached 0, then close the underlying
+ ** shared-memory file, too */
+ winShmEnterMutex();
+ assert( pFile->nRef>0 );
+ pFile->nRef--;
+ if( pFile->nRef==0 ){
+ if( deleteFlag ) winDelete(pVfs, pFile->zFilename, 0);
+ winShmPurge();
+ }
+ winShmLeaveMutex();
+
+ return SQLITE_OK;
+}
+
+/*
+** Query and/or changes the size of the underlying storage for
+** a shared-memory segment. The reqSize parameter is the new size
+** of the underlying storage, or -1 to do just a query. The size
+** of the underlying storage (after resizing if resizing occurs) is
+** written into pNewSize.
+**
+** This routine does not (necessarily) change the size of the mapping
+** of the underlying storage into memory. Use xShmGet() to change
+** the mapping size.
+**
+** The reqSize parameter is the minimum size requested. The implementation
+** is free to expand the storage to some larger amount if it chooses.
+*/
+static int winShmSize(
+ sqlite3_vfs *pVfs, /* The VFS */
+ sqlite3_shm *pSharedMem, /* Pointer returned by winShmOpen() */
+ int reqSize, /* Requested size. -1 for query only */
+ int *pNewSize /* Write new size here */
+){
+ winShm *p = (winShm*)pSharedMem;
+ winShmFile *pFile = p->pFile;
+ int rc = SQLITE_OK;
+
+ UNUSED_PARAMETER(pVfs);
+
+ if( reqSize>=0 ){
+ reqSize = (reqSize + SQLITE_WIN_SHM_INCR - 1)/SQLITE_WIN_SHM_INCR;
+ reqSize *= SQLITE_WIN_SHM_INCR;
+ rc = winTruncate((sqlite3_file *)&pFile->hFile, reqSize);
+ }
+ if( SQLITE_OK==rc ){
+ sqlite3_int64 sz;
+ rc = winFileSize((sqlite3_file *)&pFile->hFile, &sz);
+ if( SQLITE_OK==rc ){
+ *pNewSize = (int)sz;
+ }else{
+ *pNewSize = 0;
+ rc = SQLITE_IOERR;
+ }
+ }
+ return rc;
+}
+
+
+/*
+** Map the shared storage into memory. The minimum size of the
+** mapping should be reqMapSize if reqMapSize is positive. If
+** reqMapSize is zero or negative, the implementation can choose
+** whatever mapping size is convenient.
+**
+** *ppBuf is made to point to the memory which is a mapping of the
+** underlying storage. A mutex is acquired to prevent other threads
+** from running while *ppBuf is in use in order to prevent other threads
+** remapping *ppBuf out from under this thread. The winShmRelease()
+** call will release the mutex. However, if the lock state is CHECKPOINT,
+** the mutex is not acquired because CHECKPOINT will never remap the
+** buffer. RECOVER might remap, though, so CHECKPOINT will acquire
+** the mutex if and when it promotes to RECOVER.
+**
+** RECOVER needs to be atomic. The same mutex that prevents *ppBuf from
+** being remapped also prevents more than one thread from being in
+** RECOVER at a time. But, RECOVER sometimes wants to remap itself.
+** To prevent RECOVER from losing its lock while remapping, the
+** mutex is not released by winShmRelease() when in RECOVER.
+**
+** *pNewMapSize is set to the size of the mapping.
+**
+** *ppBuf and *pNewMapSize might be NULL and zero if no space has
+** yet been allocated to the underlying storage.
+*/
+static int winShmGet(
+ sqlite3_vfs *pVfs, /* The VFS */
+ sqlite3_shm *pSharedMem, /* Pointer returned by winShmOpen() */
+ int reqMapSize, /* Requested size of mapping. -1 means don't care */
+ int *pNewMapSize, /* Write new size of mapping here */
+ void **ppBuf /* Write mapping buffer origin here */
+){
+ winShm *p = (winShm*)pSharedMem;
+ winShmFile *pFile = p->pFile;
+ int rc = SQLITE_OK;
+
+ if( p->lockState!=SQLITE_SHM_CHECKPOINT && p->hasMutexBuf==0 ){
+ assert( sqlite3_mutex_notheld(pFile->mutex) );
+ sqlite3_mutex_enter(pFile->mutexBuf);
+ p->hasMutexBuf = 1;
+ }
+ sqlite3_mutex_enter(pFile->mutex);
+ if( pFile->szMap==0 || reqMapSize>pFile->szMap ){
+ int actualSize;
+ if( winShmSize(pVfs, pSharedMem, -1, &actualSize)==SQLITE_OK
+ && reqMapSize<actualSize
+ ){
+ reqMapSize = actualSize;
+ }
+ if( pFile->pMMapBuf ){
+ if( !UnmapViewOfFile(pFile->pMMapBuf) ){
+ pFile->lastErrno = GetLastError();
+ rc = SQLITE_IOERR;
+ }
+ CloseHandle(pFile->hMap);
+ pFile->hMap = INVALID_HANDLE_VALUE;
+ }
+ if( SQLITE_OK == rc ){
+ pFile->pMMapBuf = 0;
+ if( reqMapSize == 0 ){
+ /* can't create 0 byte file mapping in Windows */
+ pFile->szMap = 0;
+ }else{
+ /* create the file mapping object */
+ if( INVALID_HANDLE_VALUE == pFile->hMap ){
+ /* TBD provide an object name to each file
+ ** mapping so it can be re-used across processes.
+ */
+ pFile->hMap = CreateFileMapping(pFile->hFile.h,
+ NULL,
+ PAGE_READWRITE,
+ 0,
+ reqMapSize,
+ NULL);
+ }
+ if( NULL==pFile->hMap ){
+ pFile->lastErrno = GetLastError();
+ rc = SQLITE_IOERR;
+ pFile->szMap = 0;
+ pFile->hMap = INVALID_HANDLE_VALUE;
+ }else{
+ pFile->pMMapBuf = MapViewOfFile(pFile->hMap,
+ FILE_MAP_WRITE | FILE_MAP_READ,
+ 0,
+ 0,
+ reqMapSize);
+ if( !pFile->pMMapBuf ){
+ pFile->lastErrno = GetLastError();
+ rc = SQLITE_IOERR;
+ pFile->szMap = 0;
+ }else{
+ pFile->szMap = reqMapSize;
+ }
+ }
+ }
+ }
+ }
+ *pNewMapSize = pFile->szMap;
+ *ppBuf = pFile->pMMapBuf;
+ sqlite3_mutex_leave(pFile->mutex);
+ return rc;
+}
+
+/*
+** Release the lock held on the shared memory segment so that other
+** threads are free to resize it if necessary.
+**
+** If the lock is not currently held, this routine is a harmless no-op.
+**
+** If the shared-memory object is in lock state RECOVER, then we do not
+** really want to release the lock, so in that case too, this routine
+** is a no-op.
+*/
+static int winShmRelease(sqlite3_vfs *pVfs, sqlite3_shm *pSharedMem){
+ winShm *p = (winShm*)pSharedMem;
+ UNUSED_PARAMETER(pVfs);
+ if( p->hasMutexBuf && p->lockState!=SQLITE_SHM_RECOVER ){
+ winShmFile *pFile = p->pFile;
+ assert( sqlite3_mutex_notheld(pFile->mutex) );
+ sqlite3_mutex_leave(pFile->mutexBuf);
+ p->hasMutexBuf = 0;
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Symbolic names for LOCK states used for debugging.
+*/
+#ifdef SQLITE_DEBUG
+static const char *azLkName[] = {
+ "UNLOCK",
+ "READ",
+ "READ_FULL",
+ "WRITE",
+ "PENDING",
+ "CHECKPOINT",
+ "RECOVER"
+};
+#endif
+
+
+/*
+** Change the lock state for a shared-memory segment.
+*/
+static int winShmLock(
+ sqlite3_vfs *pVfs, /* The VFS */
+ sqlite3_shm *pSharedMem, /* Pointer from winShmOpen() */
+ int desiredLock, /* One of SQLITE_SHM_xxxxx locking states */
+ int *pGotLock /* The lock you actually got */
+){
+ winShm *p = (winShm*)pSharedMem;
+ winShmFile *pFile = p->pFile;
+ int rc = SQLITE_PROTOCOL;
+
+ UNUSED_PARAMETER(pVfs);
+
+ /* Note that SQLITE_SHM_READ_FULL and SQLITE_SHM_PENDING are never
+ ** directly requested; they are side effects from requesting
+ ** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
+ */
+ assert( desiredLock==SQLITE_SHM_UNLOCK
+ || desiredLock==SQLITE_SHM_READ
+ || desiredLock==SQLITE_SHM_WRITE
+ || desiredLock==SQLITE_SHM_CHECKPOINT
+ || desiredLock==SQLITE_SHM_RECOVER );
+
+ /* Return directly if this is just a lock state query, or if
+ ** the connection is already in the desired locking state.
+ */
+ if( desiredLock==p->lockState
+ || (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
+ ){
+ OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s and got %s\n",
+ p->id, (int)GetCurrentProcessId(), azLkName[desiredLock], azLkName[p->lockState]));
+ if( pGotLock ) *pGotLock = p->lockState;
+ return SQLITE_OK;
+ }
+
+ OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s->%s\n",
+ p->id, (int)GetCurrentProcessId(), azLkName[p->lockState], azLkName[desiredLock]));
+
+ if( desiredLock==SQLITE_SHM_RECOVER && !p->hasMutexBuf ){
+ assert( sqlite3_mutex_notheld(pFile->mutex) );
+ sqlite3_mutex_enter(pFile->mutexBuf);
+ p->hasMutexBuf = 1;
+ }
+ sqlite3_mutex_enter(pFile->mutex);
+ switch( desiredLock ){
+ case SQLITE_SHM_UNLOCK: {
+ assert( p->lockState!=SQLITE_SHM_RECOVER );
+ winShmUnlock(pFile, p, WIN_SHM_A|WIN_SHM_B|WIN_SHM_C|WIN_SHM_D);
+ rc = SQLITE_OK;
+ p->lockState = SQLITE_SHM_UNLOCK;
+ break;
+ }
+ case SQLITE_SHM_READ: {
+ if( p->lockState==SQLITE_SHM_UNLOCK ){
+ int nAttempt;
+ rc = SQLITE_BUSY;
+ assert( p->lockState==SQLITE_SHM_UNLOCK );
+ for(nAttempt=0; nAttempt<5 && rc==SQLITE_BUSY; nAttempt++){
+ rc = winShmSharedLock(pFile, p, WIN_SHM_A|WIN_SHM_B);
+ if( rc==SQLITE_BUSY ){
+ rc = winShmSharedLock(pFile, p, WIN_SHM_D);
+ if( rc==SQLITE_OK ){
+ p->lockState = SQLITE_SHM_READ_FULL;
+ }
+ }else{
+ winShmUnlock(pFile, p, WIN_SHM_B);
+ p->lockState = SQLITE_SHM_READ;
+ }
+ }
+ }else{
+ assert( p->lockState==SQLITE_SHM_WRITE
+ || p->lockState==SQLITE_SHM_RECOVER );
+ rc = winShmSharedLock(pFile, p, WIN_SHM_A);
+ winShmUnlock(pFile, p, WIN_SHM_C|WIN_SHM_D);
+ p->lockState = SQLITE_SHM_READ;
+ }
+ break;
+ }
+ case SQLITE_SHM_WRITE: {
+ assert( p->lockState==SQLITE_SHM_READ
+ || p->lockState==SQLITE_SHM_READ_FULL );
+ rc = winShmExclusiveLock(pFile, p, WIN_SHM_C|WIN_SHM_D);
+ if( rc==SQLITE_OK ){
+ p->lockState = SQLITE_SHM_WRITE;
+ }
+ break;
+ }
+ case SQLITE_SHM_CHECKPOINT: {
+ assert( p->lockState==SQLITE_SHM_UNLOCK
+ || p->lockState==SQLITE_SHM_PENDING
+ );
+ if( p->lockState==SQLITE_SHM_UNLOCK ){
+ rc = winShmExclusiveLock(pFile, p, WIN_SHM_B|WIN_SHM_C);
+ if( rc==SQLITE_OK ){
+ p->lockState = SQLITE_SHM_PENDING;
+ }
+ }
+ if( p->lockState==SQLITE_SHM_PENDING ){
+ rc = winShmExclusiveLock(pFile, p, WIN_SHM_A);
+ if( rc==SQLITE_OK ){
+ p->lockState = SQLITE_SHM_CHECKPOINT;
+ }
+ }
+ break;
+ }
+ default: {
+ assert( desiredLock==SQLITE_SHM_RECOVER );
+ assert( p->lockState==SQLITE_SHM_READ
+ || p->lockState==SQLITE_SHM_READ_FULL
+ );
+ assert( sqlite3_mutex_held(pFile->mutexBuf) );
+ rc = winShmExclusiveLock(pFile, p, WIN_SHM_C);
+ if( rc==SQLITE_OK ){
+ p->lockState = SQLITE_SHM_RECOVER;
+ }
+ break;
+ }
+ }
+ sqlite3_mutex_leave(pFile->mutex);
+ OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %s\n",
+ p->id, (int)GetCurrentProcessId(), azLkName[p->lockState]));
+ if( pGotLock ) *pGotLock = p->lockState;
+ return rc;
+}
+
+#else
+# define winShmOpen 0
+# define winShmSize 0
+# define winShmGet 0
+# define winShmRelease 0
+# define winShmLock 0
+# define winShmClose 0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+
/*
** Initialize and deinitialize the operating system interface.
*/
int sqlite3_os_init(void){
static sqlite3_vfs winVfs = {
- 1, /* iVersion */
- sizeof(winFile), /* szOsFile */
- MAX_PATH, /* mxPathname */
- 0, /* pNext */
- "win32", /* zName */
- 0, /* pAppData */
-
- winOpen, /* xOpen */
- winDelete, /* xDelete */
- winAccess, /* xAccess */
- winFullPathname, /* xFullPathname */
- winDlOpen, /* xDlOpen */
- winDlError, /* xDlError */
- winDlSym, /* xDlSym */
- winDlClose, /* xDlClose */
- winRandomness, /* xRandomness */
- winSleep, /* xSleep */
- winCurrentTime, /* xCurrentTime */
- winGetLastError, /* xGetLastError */
+ 2, /* iVersion */
+ sizeof(winFile), /* szOsFile */
+ MAX_PATH, /* mxPathname */
+ 0, /* pNext */
+ "win32", /* zName */
+ 0, /* pAppData */
+ winOpen, /* xOpen */
+ winDelete, /* xDelete */
+ winAccess, /* xAccess */
+ winFullPathname, /* xFullPathname */
+ winDlOpen, /* xDlOpen */
+ winDlError, /* xDlError */
+ winDlSym, /* xDlSym */
+ winDlClose, /* xDlClose */
+ winRandomness, /* xRandomness */
+ winSleep, /* xSleep */
+ winCurrentTime, /* xCurrentTime */
+ winGetLastError, /* xGetLastError */
+ winShmOpen, /* xShmOpen */
+ winShmSize, /* xShmSize */
+ winShmGet, /* xShmGet */
+ winShmRelease, /* xShmRelease */
+ winShmLock, /* xShmLock */
+ winShmClose, /* xShmClose */
+ 0, /* xRename */
+ winCurrentTimeInt64, /* xCurrentTimeInt64 */
};
sqlite3_vfs_register(&winVfs, 1);
projects / thirdparty / sqlite.git / commitdiff
