SQLite

!ENDIF

# Set this to non-0 to enable support for the rbu extension.
#
!IFNDEF RBU
RBU = 0
!ENDIF

# Set this to non-0 to enable support for blocking locks.
#
!IFNDEF SETLK_TIMEOUT
SETLK_TIMEOUT = 0
!ENDIF

# Set the source code file to be used by executables and libraries when
# they need the amalgamation.
#
!IFNDEF SQLITE3C
!IF $(SPLIT_AMALGAMATION)!=0
SQLITE3C = sqlite3-all.c

EXT_FEATURE_FLAGS = $(EXT_FEATURE_FLAGS) -DSQLITE_ENABLE_FTS4=1
EXT_FEATURE_FLAGS = $(EXT_FEATURE_FLAGS) -DSQLITE_SYSTEM_MALLOC=1
EXT_FEATURE_FLAGS = $(EXT_FEATURE_FLAGS) -DSQLITE_OMIT_LOCALTIME=1
!ELSE
EXT_FEATURE_FLAGS =
!ENDIF
!ENDIF

!IF $(SETLK_TIMEOUT)!=0
OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_SETLK_TIMEOUT
!ENDIF

###############################################################################
############################### END OF OPTIONS ################################
###############################################################################

# When compiling for the Windows 10 platform, the PLATFORM macro must be set
# to an appropriate value (e.g. x86, x64, arm, arm64, etc).

  ** remove the entry from the db->aDb[] array. i.e. put everything back the
  ** way we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    db->init.iDb = 0;
    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( db->setlkFlags & SQLITE_SETLK_BLOCK_ON_CONNECT ){
      int val = 1;
      sqlite3_file *fd = sqlite3PagerFile(sqlite3BtreePager(pNew->pBt));
      sqlite3OsFileControlHint(fd, SQLITE_FCNTL_BLOCK_ON_CONNECT, &val);
    }
#endif
    if( !REOPEN_AS_MEMDB(db) ){
      rc = sqlite3Init(db, &zErrDyn);
    }
    sqlite3BtreeLeaveAll(db);
    assert( zErrDyn==0 || rc!=SQLITE_OK );
  }
  if( rc ){

  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->busyHandler.xBusyHandler = xBusy;
  db->busyHandler.pBusyArg = pArg;
  db->busyHandler.nBusy = 0;
  db->busyTimeout = 0;
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  db->setlkTimeout = 0;
#endif
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/*
** This routine sets the progress callback for an Sqlite database to the

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  if( ms>0 ){
    sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
                             (void*)db);
    db->busyTimeout = ms;
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    db->setlkTimeout = ms;
#endif
  }else{
    sqlite3_busy_handler(db, 0, 0);
  }
  return SQLITE_OK;
}

/*
** Set the setlk timeout value.
*/
int sqlite3_setlk_timeout(sqlite3 *db, int ms, int flags){
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  int iDb;
  int bBOC = ((flags & SQLITE_SETLK_BLOCK_ON_CONNECT) ? 1 : 0);
#endif
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  if( ms<-1 ) return SQLITE_RANGE;
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  db->setlkTimeout = ms;
  db->setlkFlags = flags;
  sqlite3BtreeEnterAll(db);
  for(iDb=0; iDb<db->nDb; iDb++){
    Btree *pBt = db->aDb[iDb].pBt;
    if( pBt ){
      sqlite3_file *fd = sqlite3PagerFile(sqlite3BtreePager(pBt));
      sqlite3OsFileControlHint(fd, SQLITE_FCNTL_BLOCK_ON_CONNECT, (void*)&bBOC);
    }
  }
  sqlite3BtreeLeaveAll(db);
#endif
  return SQLITE_OK;
}

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite3_interrupt(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db)

  int openFlags;                      /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  unsigned iBusyTimeout;              /* Wait this many millisec on locks */
  int bBlockOnConnect;                /* True to block for SHARED locks */
#endif
#if OS_VXWORKS
  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifdef SQLITE_DEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated

      if( rc<0 ) return rc;
      pInode->bProcessLock = 1;
      pInode->nLock++;
    }else{
      rc = 0;
    }
  }else{
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( pFile->bBlockOnConnect && pLock->l_type==F_RDLCK 
     && pLock->l_start==SHARED_FIRST && pLock->l_len==SHARED_SIZE
    ){
      rc = osFcntl(pFile->h, F_SETLKW, pLock);
    }else
#endif
    rc = osSetPosixAdvisoryLock(pFile->h, pLock, pFile);
  }
  return rc;
}

/*
** Lock the file with the lock specified by parameter eFileLock - one

    case SQLITE_FCNTL_HAS_MOVED: {
      *(int*)pArg = fileHasMoved(pFile);
      return SQLITE_OK;
    }
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    case SQLITE_FCNTL_LOCK_TIMEOUT: {
      int iOld = pFile->iBusyTimeout;
      int iNew = *(int*)pArg;
#if SQLITE_ENABLE_SETLK_TIMEOUT==1
      pFile->iBusyTimeout = iNew<0 ? 0x7FFFFFFF : (unsigned)iNew;
#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
      pFile->iBusyTimeout = !!(*(int*)pArg);
#else
# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
#endif
      *(int*)pArg = iOld;
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_BLOCK_ON_CONNECT: {
      int iNew = *(int*)pArg;
      pFile->bBlockOnConnect = iNew;
      return SQLITE_OK;
    }
#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */
#if SQLITE_MAX_MMAP_SIZE>0
    case SQLITE_FCNTL_MMAP_SIZE: {
      i64 newLimit = *(i64*)pArg;
      int rc = SQLITE_OK;
      if( newLimit>sqlite3GlobalConfig.mxMmap ){
        newLimit = sqlite3GlobalConfig.mxMmap;
      }

  **
  ** In other words, if this is a blocking lock, none of the locks that
  ** occur later in the above list than the lock being obtained may be
  ** held.
  **
  ** It is not permitted to block on the RECOVER lock.
  */
#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && defined(SQLITE_DEBUG)
  {
    u16 lockMask = (p->exclMask|p->sharedMask);
    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
          (ofst!=2)                                   /* not RECOVER */
       && (ofst!=1 || lockMask==0 || lockMask==2)
       && (ofst!=0 || lockMask<3)
       && (ofst<3  || lockMask<(1<<ofst))

#if SQLITE_MAX_MMAP_SIZE>0
  int nFetchOut;                /* Number of outstanding xFetch references */
  HANDLE hMap;                  /* Handle for accessing memory mapping */
  void *pMapRegion;             /* Area memory mapped */
  sqlite3_int64 mmapSize;       /* Size of mapped region */
  sqlite3_int64 mmapSizeMax;    /* Configured FCNTL_MMAP_SIZE value */
#endif
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  DWORD iBusyTimeout;        /* Wait this many millisec on locks */
  int bBlockOnConnect;
#endif
};

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
# define winFileBusyTimeout(pDbFd) pDbFd->iBusyTimeout
#else
# define winFileBusyTimeout(pDbFd) 0
#endif

/*
** The winVfsAppData structure is used for the pAppData member for all of the
** Win32 VFS variants.
*/
typedef struct winVfsAppData winVfsAppData;
struct winVfsAppData {

#else
  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
        LPWSTR*))aSyscall[25].pCurrent)

/*
** For GetLastError(), MSDN says:
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
  { "GetLastError",            (SYSCALL)GetLastError,            0 },

#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)

#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
#if SQLITE_OS_WINCE
  /* The GetProcAddressA() routine is only available on Windows CE. */

#else
  { "CreateEventExW",          (SYSCALL)0,                       0 },
#endif

#define osCreateEventExW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,LPCWSTR, \
        DWORD,DWORD))aSyscall[62].pCurrent)


/*
** For WaitForSingleObject(), MSDN says:

**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
  { "WaitForSingleObject",     (SYSCALL)WaitForSingleObject,     0 },


#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[63].pCurrent)

#if !SQLITE_OS_WINCE
  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
#else

#else
  { "FlushViewOfFile",          (SYSCALL)0,                      0 },
#endif

#define osFlushViewOfFile \
        ((BOOL(WINAPI*)(LPCVOID,SIZE_T))aSyscall[79].pCurrent)

/*
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined, we require CreateEvent()
** to implement blocking locks with timeouts. MSDN says:
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  { "CreateEvent",              (SYSCALL)CreateEvent,            0 },
#else
  { "CreateEvent",              (SYSCALL)0,                      0 },
#endif

#define osCreateEvent ( \
    (HANDLE(WINAPI*) (LPSECURITY_ATTRIBUTES,BOOL,BOOL,LPCSTR)) \
    aSyscall[80].pCurrent \
)

/*
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined, we require CancelIo()
** for the case where a timeout expires and a lock request must be 
** cancelled.
**
** Minimum supported client: Windows XP [desktop apps | UWP apps]
** Minimum supported server: Windows Server 2003 [desktop apps | UWP apps]
*/
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  { "CancelIo",                 (SYSCALL)CancelIo,               0 },
#else
  { "CancelIo",                 (SYSCALL)0,                      0 },
#endif

#define osCancelIo ((BOOL(WINAPI*)(HANDLE))aSyscall[81].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK upon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.

    osGetVersionExW(&sInfo);
    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#endif
  }
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#elif SQLITE_TEST
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2
      || osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0
  ;
#else
  /*
  ** NOTE: All sub-platforms where the GetVersionEx[AW] functions are
  **       deprecated are always assumed to be based on the NT kernel.
  */
  return 1;
#endif

    return osLockFileEx(*phFile, flags, 0, numBytesLow, numBytesHigh, &ovlp);
  }else{
    return osLockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
                      numBytesHigh);
  }
#endif
}

/*
** Lock a region of nByte bytes starting at offset offset of file hFile.
** Take an EXCLUSIVE lock if parameter bExclusive is true, or a SHARED lock
** otherwise. If nMs is greater than zero and the lock cannot be obtained
** immediately, block for that many ms before giving up.
**
** This function returns SQLITE_OK if the lock is obtained successfully. If
** some other process holds the lock, SQLITE_BUSY is returned if nMs==0, or
** SQLITE_BUSY_TIMEOUT otherwise. Or, if an error occurs, SQLITE_IOERR.
*/
static int winHandleLockTimeout(
  HANDLE hFile,
  DWORD offset,
  DWORD nByte,
  int bExcl,
  DWORD nMs
){
  DWORD flags = LOCKFILE_FAIL_IMMEDIATELY | (bExcl?LOCKFILE_EXCLUSIVE_LOCK:0);
  int rc = SQLITE_OK;
  BOOL ret;

  if( !osIsNT() ){
    ret = winLockFile(&hFile, flags, offset, 0, nByte, 0);
  }else{
    OVERLAPPED ovlp;
    memset(&ovlp, 0, sizeof(OVERLAPPED));
    ovlp.Offset = offset;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( nMs!=0 ){
      flags &= ~LOCKFILE_FAIL_IMMEDIATELY;
    }
    ovlp.hEvent = osCreateEvent(NULL, TRUE, FALSE, NULL);
    if( ovlp.hEvent==NULL ){
      return SQLITE_IOERR_LOCK;
    }
#endif

    ret = osLockFileEx(hFile, flags, 0, nByte, 0, &ovlp);

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    /* If SQLITE_ENABLE_SETLK_TIMEOUT is defined, then the file-handle was
    ** opened with FILE_FLAG_OVERHEAD specified. In this case, the call to
    ** LockFileEx() may fail because the request is still pending. This can
    ** happen even if LOCKFILE_FAIL_IMMEDIATELY was specified.  
    **
    ** If nMs is 0, then LOCKFILE_FAIL_IMMEDIATELY was set in the flags 
    ** passed to LockFileEx(). In this case, if the operation is pending,
    ** block indefinitely until it is finished.
    **
    ** Otherwise, wait for up to nMs ms for the operation to finish. nMs
    ** may be set to INFINITE.
    */
    if( !ret && GetLastError()==ERROR_IO_PENDING ){
      DWORD nDelay = (nMs==0 ? INFINITE : nMs);
      DWORD res = osWaitForSingleObject(ovlp.hEvent, nDelay);
      if( res==WAIT_OBJECT_0 ){
        ret = TRUE;
      }else if( res==WAIT_TIMEOUT ){
        rc = SQLITE_BUSY_TIMEOUT;
      }else{
        /* Some other error has occurred */
        rc = SQLITE_IOERR_LOCK;
      }

      /* If it is still pending, cancel the LockFileEx() call. */
      osCancelIo(hFile);
    }

    osCloseHandle(ovlp.hEvent);
#endif
  }

  if( rc==SQLITE_OK && !ret ){
    rc = SQLITE_BUSY;
  }
  return rc;
}

/*
** Unlock a file region.
 */
static BOOL winUnlockFile(
  LPHANDLE phFile,
  DWORD offsetLow,

    return osUnlockFileEx(*phFile, 0, numBytesLow, numBytesHigh, &ovlp);
  }else{
    return osUnlockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
                        numBytesHigh);
  }
#endif
}

/*
** Remove an nByte lock starting at offset iOff from HANDLE h.
*/
static int winHandleUnlock(HANDLE h, int iOff, int nByte){
  BOOL ret = winUnlockFile(&h, iOff, 0, nByte, 0);
  return (ret ? SQLITE_OK : SQLITE_IOERR_UNLOCK);
}

/*****************************************************************************
** The next group of routines implement the I/O methods specified
** by the sqlite3_io_methods object.
******************************************************************************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_SET_FILE_POINTER
# define INVALID_SET_FILE_POINTER ((DWORD)-1)
#endif

/*
** Seek the file handle h to offset nByte of the file.
**
** If successful, return SQLITE_OK. Or, if an error occurs, return an SQLite

** error code. 
*/
static int winHandleSeek(HANDLE h, sqlite3_int64 iOffset){
  int rc = SQLITE_OK;             /* Return value */

#if !SQLITE_OS_WINRT
  LONG upperBits;                 /* Most sig. 32 bits of new offset */
  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
  DWORD dwRet;                    /* Value returned by SetFilePointer() */




  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  dwRet = osSetFilePointer(h, lowerBits, &upperBits, FILE_BEGIN);

  /* API oddity: If successful, SetFilePointer() returns a dword
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN,
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine
  ** whether an error has actually occurred, it is also necessary to call
  ** GetLastError().  */



  if( dwRet==INVALID_SET_FILE_POINTER ){
    DWORD lastErrno = osGetLastError();
    if( lastErrno!=NO_ERROR ){
      rc = SQLITE_IOERR_SEEK;



    }
  }


#else

  /* This implementation works for WinRT. */


  LARGE_INTEGER x;                /* The new offset */
  BOOL bRet;                      /* Value returned by SetFilePointerEx() */

  x.QuadPart = iOffset;
  bRet = osSetFilePointerEx(h, x, 0, FILE_BEGIN);

  if(!bRet){

    rc = SQLITE_IOERR_SEEK;
  }
#endif

  OSTRACE(("SEEK file=%p, offset=%lld rc=%s\n", h, iOffset, sqlite3ErrName(rc)));
  return rc;
}

/*
** Move the current position of the file handle passed as the first
** argument to offset iOffset within the file. If successful, return 0.
** Otherwise, set pFile->lastErrno and return non-zero.
*/
static int winSeekFile(winFile *pFile, sqlite3_int64 iOffset){
  int rc;

  rc = winHandleSeek(pFile->h, iOffset);
  if( rc!=SQLITE_OK ){
    pFile->lastErrno = osGetLastError();
    winLogError(rc, pFile->lastErrno, "winSeekFile", pFile->zPath);
  }
  return rc;

}


#if SQLITE_MAX_MMAP_SIZE>0
/* Forward references to VFS helper methods used for memory mapped files */
static int winMapfile(winFile*, sqlite3_int64);
static int winUnmapfile(winFile*);
#endif

  }else{
    winLogIoerr(nRetry, __LINE__);
  }
  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
           osGetCurrentProcessId(), pFile, pFile->h));
  return SQLITE_OK;
}

/*
** Truncate the file opened by handle h to nByte bytes in size.
*/
static int winHandleTruncate(HANDLE h, sqlite3_int64 nByte){ 
  int rc = SQLITE_OK;             /* Return code */
  rc = winHandleSeek(h, nByte);
  if( rc==SQLITE_OK ){
    if( 0==osSetEndOfFile(h) ){
      rc = SQLITE_IOERR_TRUNCATE;
    }
  }
  return rc;
}

/*
** Determine the size in bytes of the file opened by the handle passed as 
** the first argument.
*/
static int winHandleSize(HANDLE h, sqlite3_int64 *pnByte){ 
  int rc = SQLITE_OK;

#if SQLITE_OS_WINRT
  FILE_STANDARD_INFO info;
  BOOL b;
  b = osGetFileInformationByHandleEx(h, FileStandardInfo, &info, sizeof(info));
  if( b ){
    *pnByte = info.EndOfFile.QuadPart;
  }else{
    rc = SQLITE_IOERR_FSTAT;
  }
#else
  DWORD upperBits = 0;
  DWORD lowerBits = 0;

  assert( pnByte );
  lowerBits = osGetFileSize(h, &upperBits);
  *pnByte = (((sqlite3_int64)upperBits)<<32) + lowerBits;
  if( lowerBits==INVALID_FILE_SIZE && osGetLastError()!=NO_ERROR ){
    rc = SQLITE_IOERR_FSTAT;
  }
#endif

  return rc;
}

/*
** Close the handle passed as the only argument.
*/
static void winHandleClose(HANDLE h){
  if( h!=INVALID_HANDLE_VALUE ){
    osCloseHandle(h);
  }
}

/*
** Truncate an open file to a specified size
*/
static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
  winFile *pFile = (winFile*)id;  /* File handle object */
  int rc = SQLITE_OK;             /* Return code for this function */

#endif

/*
** Acquire a reader lock.
** Different API routines are called depending on whether or not this
** is Win9x or WinNT.
*/
static int winGetReadLock(winFile *pFile, int bBlock){
  int res;
  DWORD mask = ~(bBlock ? LOCKFILE_FAIL_IMMEDIATELY : 0);
  OSTRACE(("READ-LOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
  if( osIsNT() ){
#if SQLITE_OS_WINCE
    /*
    ** NOTE: Windows CE is handled differently here due its lack of the Win32
    **       API LockFileEx.
    */
    res = winceLockFile(&pFile->h, SHARED_FIRST, 0, 1, 0);
#else
    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS&mask, SHARED_FIRST, 0,
                      SHARED_SIZE, 0);
#endif
  }
#ifdef SQLITE_WIN32_HAS_ANSI
  else{
    int lk;
    sqlite3_randomness(sizeof(lk), &lk);
    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS&mask,
                      SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
  }
#endif
  if( res == 0 ){
    pFile->lastErrno = osGetLastError();
    /* No need to log a failure to lock */
  }

  /* Make sure the locking sequence is correct
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );

  /* Lock the PENDING_LOCK byte if we need to acquire an EXCLUSIVE lock or
  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
  ** the PENDING_LOCK byte is temporary.
  */
  newLocktype = pFile->locktype;
  if( locktype==SHARED_LOCK
   || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
  ){
    int cnt = 3;

    /* Flags for the LockFileEx() call. This should be an exclusive lock if
    ** this call is to obtain EXCLUSIVE, or a shared lock if this call is to
    ** obtain SHARED.  */
    int flags = LOCKFILE_FAIL_IMMEDIATELY;
    if( locktype==EXCLUSIVE_LOCK ){
      flags |= LOCKFILE_EXCLUSIVE_LOCK;
    }
    while( cnt>0 ){
      /* Try 3 times to get the pending lock.  This is needed to work
      ** around problems caused by indexing and/or anti-virus software on
      ** Windows systems.
      **
      ** If you are using this code as a model for alternative VFSes, do not
      ** copy this retry logic.  It is a hack intended for Windows only.  */
      res = winLockFile(&pFile->h, flags, PENDING_BYTE, 0, 1, 0);
      if( res ) break;

      lastErrno = osGetLastError();
      OSTRACE(("LOCK-PENDING-FAIL file=%p, count=%d, result=%d\n", 
            pFile->h, cnt, res
      ));

      if( lastErrno==ERROR_INVALID_HANDLE ){
        pFile->lastErrno = lastErrno;
        rc = SQLITE_IOERR_LOCK;
        OSTRACE(("LOCK-FAIL file=%p, count=%d, rc=%s\n", 
              pFile->h, cnt, sqlite3ErrName(rc)
        ));
        return rc;
      }

      cnt--;
      if( cnt>0 ) sqlite3_win32_sleep(1);
    }
    gotPendingLock = res;



  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res ){
    assert( pFile->locktype==NO_LOCK );
    res = winGetReadLock(pFile, pFile->bBlockOnConnect);
    if( res ){
      newLocktype = SHARED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

    (void)winUnlockReadLock(pFile);
    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, SHARED_FIRST, 0,
                      SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      lastErrno = osGetLastError();
      winGetReadLock(pFile, 0);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){

  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(("UNLOCK file=%p, oldLock=%d(%d), newLock=%d\n",
           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !winGetReadLock(pFile, 0) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
                       "winUnlock", pFile->zPath);
    }
  }
  if( type>=RESERVED_LOCK ){

          rc = winMapfile(pFile, -1);
        }
      }
      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
      return rc;
    }
#endif

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    case SQLITE_FCNTL_LOCK_TIMEOUT: {
      int iOld = pFile->iBusyTimeout;
      int iNew = *(int*)pArg;
#if SQLITE_ENABLE_SETLK_TIMEOUT==1
      pFile->iBusyTimeout = (iNew < 0) ? INFINITE : (DWORD)iNew;
#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
      pFile->iBusyTimeout = (DWORD)(!!iNew);
#else
# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
#endif
      *(int*)pArg = iOld;
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_BLOCK_ON_CONNECT: {
      int iNew = *(int*)pArg;
      pFile->bBlockOnConnect = iNew;
      return SQLITE_OK;
    }
#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */

  }
  OSTRACE(("FCNTL file=%p, rc=SQLITE_NOTFOUND\n", pFile->h));
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for

** this object or while reading or writing the following fields:
**
**      nRef
**      pNext
**
** The following fields are read-only after the object is created:
**

**      zFilename
**
** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
** winShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
** File-handle hSharedShm is used to (a) take the DMS lock, (b) truncate
** the *-shm file if the DMS-locking protocol demands it, and (c) map
** regions of the *-shm file into memory using MapViewOfFile() or 
** similar. Other locks are taken by individual clients using the
** winShm.hShm handles.
*/
struct winShmNode {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  char *zFilename;           /* Name of the file */
  HANDLE hSharedShm;         /* File handle open on zFilename */

  int isUnlocked;            /* DMS lock has not yet been obtained */
  int isReadonly;            /* True if read-only */
  int szRegion;              /* Size of shared-memory regions */
  int nRegion;               /* Size of array apRegion */



  struct ShmRegion {
    HANDLE hMap;             /* File handle from CreateFileMapping */
    void *pMap;
  } *aRegion;
  DWORD lastErrno;           /* The Windows errno from the last I/O error */

  int nRef;                  /* Number of winShm objects pointing to this */

  winShmNode *pNext;         /* Next in list of all winShmNode objects */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 nextShmId;              /* Next available winShm.id value */
#endif
};

/*
** A global array of all winShmNode objects.
**
** The winShmMutexHeld() must be true while reading or writing this list.
*/
static winShmNode *winShmNodeList = 0;

/*
** Structure used internally by this VFS to record the state of an
** open shared memory connection. There is one such structure for each





** winFile open on a wal mode database.



*/
struct winShm {
  winShmNode *pShmNode;      /* The underlying winShmNode object */


  u16 sharedMask;            /* Mask of shared locks held */
  u16 exclMask;              /* Mask of exclusive locks held */
  HANDLE hShm;               /* File-handle on *-shm file. For locking. */
  int bReadonly;             /* True if hShm is opened read-only */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 id;                     /* Id of this connection with its winShmNode */
#endif
};

/*
** Constants used for locking
*/
#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */













































/* Forward references to VFS methods */
static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
static int winDelete(sqlite3_vfs *,const char*,int);

/*
** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
**

                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
        UNUSED_VARIABLE_VALUE(bRc);
        bRc = osCloseHandle(p->aRegion[i].hMap);
        OSTRACE(("SHM-PURGE-CLOSE pid=%lu, region=%d, rc=%s\n",
                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
        UNUSED_VARIABLE_VALUE(bRc);
      }


      winHandleClose(p->hSharedShm);


      if( deleteFlag ){
        SimulateIOErrorBenign(1);
        sqlite3BeginBenignMalloc();
        winDelete(pVfs, p->zFilename, 0);
        sqlite3EndBenignMalloc();
        SimulateIOErrorBenign(0);
      }
      *pp = p->pNext;
      sqlite3_free(p->aRegion);
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
    }
  }
}

/*
** The DMS lock has not yet been taken on the shm file associated with
** pShmNode. Take the lock. Truncate the *-shm file if required.
** Return SQLITE_OK if successful, or an SQLite error code otherwise.
*/
static int winLockSharedMemory(winShmNode *pShmNode, DWORD nMs){
  HANDLE h = pShmNode->hSharedShm;
  int rc = SQLITE_OK;

  assert( sqlite3_mutex_held(pShmNode->mutex) );
  rc = winHandleLockTimeout(h, WIN_SHM_DMS, 1, 1, 0);
  if( rc==SQLITE_OK ){
    /* We have an EXCLUSIVE lock on the DMS byte. This means that this
    ** is the first process to open the file. Truncate it to zero bytes
    ** in this case.  */
    if( pShmNode->isReadonly ){
      rc = SQLITE_READONLY_CANTINIT;
    }else{
      rc = winHandleTruncate(h, 0);
    }

    /* Release the EXCLUSIVE lock acquired above. */
    winUnlockFile(&h, WIN_SHM_DMS, 0, 1, 0);
  }else if( (rc & 0xFF)==SQLITE_BUSY ){
    rc = SQLITE_OK;
  }

  if( rc==SQLITE_OK ){
    /* Take a SHARED lock on the DMS byte. */
    rc = winHandleLockTimeout(h, WIN_SHM_DMS, 1, 0, nMs);
    if( rc==SQLITE_OK ){
      pShmNode->isUnlocked = 0;
    }
  }

  return rc;
}


/*
** Convert a UTF-8 filename into whatever form the underlying
** operating system wants filenames in.  Space to hold the result
** is obtained from malloc and must be freed by the calling
** function.
*/
static void *winConvertFromUtf8Filename(const char *zFilename){
  void *zConverted = 0;
  if( osIsNT() ){
    zConverted = winUtf8ToUnicode(zFilename);
  }
#ifdef SQLITE_WIN32_HAS_ANSI
  else{
    zConverted = winUtf8ToMbcs(zFilename, osAreFileApisANSI());
  }
#endif


  /* caller will handle out of memory */
  return zConverted;




}

/*
** This function is used to open a handle on a *-shm file.
**
** If SQLITE_ENABLE_SETLK_TIMEOUT is defined at build time, then the file
** is opened with FILE_FLAG_OVERLAPPED specified. If not, it is not.
*/
static int winHandleOpen(
  const char *zUtf8,              /* File to open */
  int *pbReadonly,                /* IN/OUT: True for readonly handle */
  HANDLE *ph                      /* OUT: New HANDLE for file */
){
  int rc = SQLITE_OK;
  void *zConverted = 0;
  int bReadonly = *pbReadonly;
  HANDLE h = INVALID_HANDLE_VALUE;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  const DWORD flag_overlapped = FILE_FLAG_OVERLAPPED;
#else
  const DWORD flag_overlapped = 0;
#endif

  /* Convert the filename to the system encoding. */
  zConverted = winConvertFromUtf8Filename(zUtf8);
  if( zConverted==0 ){
    OSTRACE(("OPEN name=%s, rc=SQLITE_IOERR_NOMEM", zUtf8));
    rc = SQLITE_IOERR_NOMEM_BKPT;
    goto winopenfile_out;
  }

  /* Ensure the file we are trying to open is not actually a directory. */
  if( winIsDir(zConverted) ){
    OSTRACE(("OPEN name=%s, rc=SQLITE_CANTOPEN_ISDIR", zUtf8));
    rc = SQLITE_CANTOPEN_ISDIR;
    goto winopenfile_out;
  }

  /* TODO: platforms.
  ** TODO: retry-on-ioerr.
  */
  if( osIsNT() ){
#if SQLITE_OS_WINRT
    CREATEFILE2_EXTENDED_PARAMETERS extendedParameters;
    memset(&extendedParameters, 0, sizeof(extendedParameters));
    extendedParameters.dwSize = sizeof(extendedParameters);
    extendedParameters.dwFileAttributes = FILE_ATTRIBUTE_NORMAL;
    extendedParameters.dwFileFlags = flag_overlapped;
    extendedParameters.dwSecurityQosFlags = SECURITY_ANONYMOUS;
    h = osCreateFile2((LPCWSTR)zConverted,
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),/* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,      /* dwShareMode */
        OPEN_ALWAYS,                             /* dwCreationDisposition */
        &extendedParameters
    );
#else
    h = osCreateFileW((LPCWSTR)zConverted,         /* lpFileName */
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),  /* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,        /* dwShareMode */
        NULL,                                      /* lpSecurityAttributes */
        OPEN_ALWAYS,                               /* dwCreationDisposition */
        FILE_ATTRIBUTE_NORMAL|flag_overlapped,
        NULL
    );
#endif
  }else{
    /* Due to pre-processor directives earlier in this file, 
    ** SQLITE_WIN32_HAS_ANSI is always defined if osIsNT() is false. */
#ifdef SQLITE_WIN32_HAS_ANSI
    h = osCreateFileA((LPCSTR)zConverted,
        (GENERIC_READ | (bReadonly ? 0 : GENERIC_WRITE)),  /* dwDesiredAccess */
        FILE_SHARE_READ | FILE_SHARE_WRITE,        /* dwShareMode */
        NULL,                                      /* lpSecurityAttributes */
        OPEN_ALWAYS,                               /* dwCreationDisposition */
        FILE_ATTRIBUTE_NORMAL|flag_overlapped,
        NULL
    );
#endif
  }

  if( h==INVALID_HANDLE_VALUE ){
    if( bReadonly==0 ){
      bReadonly = 1;
      rc = winHandleOpen(zUtf8, &bReadonly, &h);
    }else{
      rc = SQLITE_CANTOPEN_BKPT;
    }
  }

 winopenfile_out:
  sqlite3_free(zConverted);
  *pbReadonly = bReadonly;
  *ph = h;
  return rc;
}
 

/*
** Open the shared-memory area associated with database file pDbFd.




*/
static int winOpenSharedMemory(winFile *pDbFd){
  struct winShm *p;                  /* The connection to be opened */
  winShmNode *pShmNode = 0;          /* The underlying mmapped file */
  int rc = SQLITE_OK;                /* Result code */
  winShmNode *pNew;                  /* Newly allocated winShmNode */
  int nName;                         /* Size of zName in bytes */

  assert( pDbFd->pShm==0 );    /* Not previously opened */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.  */

  p = sqlite3MallocZero( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM_BKPT;
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3MallocZero( sizeof(*pShmNode) + (i64)nName + 17 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM_BKPT;
  }
  pNew->zFilename = (char*)&pNew[1];
  pNew->hSharedShm = INVALID_HANDLE_VALUE;
  pNew->isUnlocked = 1;
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename);

  /* Open a file-handle on the *-shm file for this connection. This file-handle
  ** is only used for locking. The mapping of the *-shm file is created using
  ** the shared file handle in winShmNode.hSharedShm.  */
  p->bReadonly = sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0);
  rc = winHandleOpen(pNew->zFilename, &p->bReadonly, &p->hShm);

  /* Look to see if there is an existing winShmNode that can be used.
  ** If no matching winShmNode currently exists, then create a new one.  */

  winShmEnterMutex();
  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
    /* TBD need to come up with better match here.  Perhaps
    ** use FILE_ID_BOTH_DIR_INFO Structure.  */

    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
  }
  if( pShmNode==0 ){





    pShmNode = pNew;





    /* Allocate a mutex for this winShmNode object, if one is required. */
    if( sqlite3GlobalConfig.bCoreMutex ){
      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
      if( pShmNode->mutex==0 ) rc = SQLITE_IOERR_NOMEM_BKPT;


    }

    /* Open a file-handle to use for mappings, and for the DMS lock. */
    if( rc==SQLITE_OK ){
      HANDLE h = INVALID_HANDLE_VALUE;
      pShmNode->isReadonly = p->bReadonly;
      rc = winHandleOpen(pNew->zFilename, &pShmNode->isReadonly, &h);
      pShmNode->hSharedShm = h;
    }

    /* If successful, link the new winShmNode into the global list. If an 
    ** error occurred, free the object. */
    if( rc==SQLITE_OK ){
      pShmNode->pNext = winShmNodeList;
      winShmNodeList = pShmNode;
      pNew = 0;
    }else{


      sqlite3_mutex_free(pShmNode->mutex);
      if( pShmNode->hSharedShm!=INVALID_HANDLE_VALUE ){



        osCloseHandle(pShmNode->hSharedShm);

      }

    }


  }

  /* If no error has occurred, link the winShm object to the winShmNode and
  ** the winShm to pDbFd.  */
  if( rc==SQLITE_OK ){
    p->pShmNode = pShmNode;
    pShmNode->nRef++;
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
    p->id = pShmNode->nextShmId++;
#endif

    pDbFd->pShm = p;
  }else if( p ){
    winHandleClose(p->hShm);
    sqlite3_free(p);
  }















  assert( rc!=SQLITE_OK || pShmNode->isUnlocked==0 || pShmNode->nRegion==0 );
  winShmLeaveMutex();

  sqlite3_free(pNew);

  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying
** storage if deleteFlag is true.
*/
static int winShmUnmap(
  sqlite3_file *fd,          /* Database holding shared memory */
  int deleteFlag             /* Delete after closing if true */
){
  winFile *pDbFd;       /* Database holding shared-memory */
  winShm *p;            /* The connection to be closed */
  winShmNode *pShmNode; /* The underlying shared-memory file */


  pDbFd = (winFile*)fd;
  p = pDbFd->pShm;
  if( p==0 ) return SQLITE_OK;
  if( p->hShm!=INVALID_HANDLE_VALUE ){
    osCloseHandle(p->hShm);
  }








  pShmNode = p->pShmNode;
  winShmEnterMutex();

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too. */

  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    winShmPurge(pDbFd->pVfs, deleteFlag);
  }
  winShmLeaveMutex();

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  return SQLITE_OK;
}

/*
** Change the lock state for a shared-memory segment.
*/
static int winShmLock(
  sqlite3_file *fd,          /* Database file holding the shared memory */
  int ofst,                  /* First lock to acquire or release */
  int n,                     /* Number of locks to acquire or release */
  int flags                  /* What to do with the lock */
){
  winFile *pDbFd = (winFile*)fd;        /* Connection holding shared memory */
  winShm *p = pDbFd->pShm;              /* The shared memory being locked */

  winShmNode *pShmNode;
  int rc = SQLITE_OK;                   /* Result code */
  u16 mask = (u16)((1U<<(ofst+n)) - (1U<<ofst)); /* Mask of locks to [un]take */

  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
  pShmNode = p->pShmNode;
  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;

  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
  assert( n>=1 );
  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );

  /* Check that, if this to be a blocking lock, no locks that occur later
  ** in the following list than the lock being obtained are already held:
  **
  **   1. Checkpointer lock (ofst==1).
  **   2. Write lock (ofst==0).

  **   3. Read locks (ofst>=3 && ofst<SQLITE_SHM_NLOCK).
  **
  ** In other words, if this is a blocking lock, none of the locks that
  ** occur later in the above list than the lock being obtained may be
  ** held.
  **
  ** It is not permitted to block on the RECOVER lock.
  */
#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && defined(SQLITE_DEBUG)
  {



    u16 lockMask = (p->exclMask|p->sharedMask);


    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
          (ofst!=2)                                   /* not RECOVER */
       && (ofst!=1 || lockMask==0 || lockMask==2)
       && (ofst!=0 || lockMask<3)




       && (ofst<3  || lockMask<(1<<ofst))
    ));
  }

#endif





  /* Check if there is any work to do. There are three cases:
  **
  **    a) An unlock operation where there are locks to unlock,
  **    b) An shared lock where the requested lock is not already held
  **    c) An exclusive lock where the requested lock is not already held

  **
  ** The SQLite core never requests an exclusive lock that it already holds.
  ** This is assert()ed immediately below.  */
  assert( flags!=(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK) 
       || 0==(p->exclMask & mask)
  );
  if( ((flags & SQLITE_SHM_UNLOCK) && ((p->exclMask|p->sharedMask) & mask))


   || (flags==(SQLITE_SHM_SHARED|SQLITE_SHM_LOCK) && 0==(p->sharedMask & mask))

   || (flags==(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK))
  ){


    if( flags & SQLITE_SHM_UNLOCK ){


      /* Case (a) - unlock.  */


      assert( (p->exclMask & p->sharedMask)==0 );
      assert( !(flags & SQLITE_SHM_EXCLUSIVE) || (p->exclMask & mask)==mask );
      assert( !(flags & SQLITE_SHM_SHARED) || (p->sharedMask & mask)==mask );

      rc = winHandleUnlock(p->hShm, ofst+WIN_SHM_BASE, n);

      /* If successful, also clear the bits in sharedMask/exclMask */
      if( rc==SQLITE_OK ){
        p->exclMask = (p->exclMask & ~mask);
        p->sharedMask = (p->sharedMask & ~mask);
      }
    }else{

      int bExcl = ((flags & SQLITE_SHM_EXCLUSIVE) ? 1 : 0);

      DWORD nMs = winFileBusyTimeout(pDbFd);
      rc = winHandleLockTimeout(p->hShm, ofst+WIN_SHM_BASE, n, bExcl, nMs);

      if( rc==SQLITE_OK ){
        if( bExcl ){
          p->exclMask = (p->exclMask | mask);
        }else{
          p->sharedMask = (p->sharedMask | mask);
        }
      }








    }
  }


  OSTRACE((
      "SHM-LOCK(%d,%d,%d) pid=%lu, id=%d, sharedMask=%03x, exclMask=%03x,"
      " rc=%s\n",
      ofst, n, flags, 
      osGetCurrentProcessId(), p->id, p->sharedMask, p->exclMask,
      sqlite3ErrName(rc))
  );
  return rc;
}

/*
** Implement a memory barrier or memory fence on shared memory.
**
** All loads and stores begun before the barrier must complete before

    pShm = pDbFd->pShm;
    assert( pShm!=0 );
  }
  pShmNode = pShm->pShmNode;

  sqlite3_mutex_enter(pShmNode->mutex);
  if( pShmNode->isUnlocked ){
    /* Take the DMS lock. */
    assert( pShmNode->nRegion==0 );
    rc = winLockSharedMemory(pShmNode, winFileBusyTimeout(pDbFd));
    if( rc!=SQLITE_OK ) goto shmpage_out;

  }


  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
  if( pShmNode->nRegion<=iRegion ){
    HANDLE hShared = pShmNode->hSharedShm;
    struct ShmRegion *apNew;           /* New aRegion[] array */
    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
    sqlite3_int64 sz;                  /* Current size of wal-index file */

    pShmNode->szRegion = szRegion;

    /* The requested region is not mapped into this processes address space.
    ** Check to see if it has been allocated (i.e. if the wal-index file is
    ** large enough to contain the requested region).
    */
    rc = winHandleSize(hShared, &sz);
    if( rc!=SQLITE_OK ){

      rc = winLogError(rc, osGetLastError(), "winShmMap1", pDbFd->zPath);
      goto shmpage_out;
    }

    if( sz<nByte ){
      /* The requested memory region does not exist. If isWrite is set to
      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
      **
      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
      ** the requested memory region.  */

      if( !isWrite ) goto shmpage_out;
      rc = winHandleTruncate(hShared, nByte);
      if( rc!=SQLITE_OK ){

        rc = winLogError(rc, osGetLastError(), "winShmMap2", pDbFd->zPath);
        goto shmpage_out;
      }
    }

    /* Map the requested memory region into this processes address space. */
    apNew = (struct ShmRegion*)sqlite3_realloc64(
        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
    );
    if( !apNew ){
      rc = SQLITE_IOERR_NOMEM_BKPT;
      goto shmpage_out;
    }
    pShmNode->aRegion = apNew;

    if( pShmNode->isReadonly ){
      protect = PAGE_READONLY;
      flags = FILE_MAP_READ;
    }

    while( pShmNode->nRegion<=iRegion ){
      HANDLE hMap = NULL;         /* file-mapping handle */
      void *pMap = 0;             /* Mapped memory region */

#if SQLITE_OS_WINRT
      hMap = osCreateFileMappingFromApp(hShared, NULL, protect, nByte, NULL);


#elif defined(SQLITE_WIN32_HAS_WIDE)
      hMap = osCreateFileMappingW(hShared, NULL, protect, 0, nByte, NULL);


#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
      hMap = osCreateFileMappingA(hShared, NULL, protect, 0, nByte, NULL);


#endif

      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%d, rc=%s\n",
               osGetCurrentProcessId(), pShmNode->nRegion, nByte,
               hMap ? "ok" : "failed"));
      if( hMap ){
        int iOffset = pShmNode->nRegion*szRegion;
        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
#if SQLITE_OS_WINRT

    int iOffset = iRegion*szRegion;
    int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
    char *p = (char *)pShmNode->aRegion[iRegion].pMap;
    *pp = (void *)&p[iOffsetShift];
  }else{
    *pp = 0;
  }
  if( pShmNode->isReadonly && rc==SQLITE_OK ){
    rc = SQLITE_READONLY;
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  return rc;
}

#else
# define winShmMap     0
# define winShmLock    0

  }
#endif
  /* caller will handle out of memory */
  return zConverted;
}
#endif





















/*
** This function returns non-zero if the specified UTF-8 string buffer
** ends with a directory separator character or one was successfully
** added to it.
*/
static int winMakeEndInDirSep(int nBuf, char *zBuf){
  if( zBuf ){

    winGetSystemCall,      /* xGetSystemCall */
    winNextSystemCall,     /* xNextSystemCall */
  };
#endif

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==82 );

  /* get memory map allocation granularity */
  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
#if SQLITE_OS_WINRT
  osGetNativeSystemInfo(&winSysInfo);
#else
  osGetSystemInfo(&winSysInfo);

** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
** to block for up to M milliseconds before failing when attempting to
** obtain a file lock using the xLock or xShmLock methods of the VFS.
** The parameter is a pointer to a 32-bit signed integer that contains
** the value that M is to be set to. Before returning, the 32-bit signed
** integer is overwritten with the previous value of M.
**
** <li>[[SQLITE_FCNTL_BLOCK_ON_CONNECT]]
** The [SQLITE_FCNTL_BLOCK_ON_CONNECT] opcode is used to configure the
** VFS to block when taking SHARED locks. This is used to implement the
** functionality associated with SQLITE_SETLK_BLOCK_ON_CONNECT.
**
** <li>[[SQLITE_FCNTL_DATA_VERSION]]
** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
** a database file.  The argument is a pointer to a 32-bit unsigned integer.
** The "data version" for the pager is written into the pointer.  The
** "data version" changes whenever any change occurs to the corresponding
** database file, either through SQL statements on the same database
** connection or through transactions committed by separate database

#define SQLITE_FCNTL_CKPT_DONE              37
#define SQLITE_FCNTL_RESERVE_BYTES          38
#define SQLITE_FCNTL_CKPT_START             39
#define SQLITE_FCNTL_EXTERNAL_READER        40
#define SQLITE_FCNTL_CKSM_FILE              41
#define SQLITE_FCNTL_RESET_CACHE            42
#define SQLITE_FCNTL_NULL_IO                43
#define SQLITE_FCNTL_BLOCK_ON_CONNECT       44

/* deprecated names */
#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO

** was defined  (using [sqlite3_busy_handler()]) prior to calling
** this routine, that other busy handler is cleared.)^
**
** See also:  [PRAGMA busy_timeout]
*/
int sqlite3_busy_timeout(sqlite3*, int ms);

/*
** CAPI3REF: Set the Setlk Timeout
** METHOD: sqlite3
**
** This routine is only useful in SQLITE_ENABLE_SETLK_TIMEOUT builds. If 
** the VFS supports blocking locks, it sets the timeout in ms used by 
** eligible locks taken on wal mode databases by the specified database 
** handle. In non-SQLITE_ENABLE_SETLK_TIMEOUT builds, or if the VFS does
** not support blocking locks, this function is a no-op.
**
** Passing 0 to this function disables blocking locks altogether. Passing 
** -1 to this function requests that the VFS blocks for a long time - 
** indefinitely if possible. The results of passing any other negative value 
** are undefined.
**
** Internally, each SQLite database handle store two timeout values - the
** busy-timeout (used for rollback mode databases, or if the VFS does not
** support blocking locks) and the setlk-timeout (used for blocking locks
** on wal-mode databases). The sqlite3_busy_timeout() method sets both
** values, this function sets only the setlk-timeout value. Therefore,
** to configure separate busy-timeout and setlk-timeout values for a single
** database handle, call sqlite3_busy_timeout() followed by this function.
**
** Whenever the number of connections to a wal mode database falls from
** 1 to 0, the last connection takes an exclusive lock on the database, 
** then checkpoints and deletes the wal file. While it is doing this, any
** new connection that tries to read from the database fails with an
** SQLITE_BUSY error. Or, if the SQLITE_SETLK_BLOCK_ON_CONNECT flag is
** passed to this API, the new connection blocks until the exclusive lock
** has been released.
*/
int sqlite3_setlk_timeout(sqlite3*, int ms, int flags);

/*
** CAPI3REF: Flags for sqlite3_setlk_timeout()
*/
#define SQLITE_SETLK_BLOCK_ON_CONNECT 0x01

/*
** CAPI3REF: Convenience Routines For Running Queries
** METHOD: sqlite3
**
** This is a legacy interface that is preserved for backwards compatibility.
** Use of this interface is not recommended.
**

  Hash aFunc;                   /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int nAnalysisLimit;           /* Number of index rows to ANALYZE */
  int busyTimeout;              /* Busy handler timeout, in msec */
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  int setlkTimeout;             /* Blocking lock timeout, in msec. -1 -> inf. */
  int setlkFlags;               /* Flags passed to setlk_timeout() */
#endif
  int nSavepoint;               /* Number of non-transaction savepoints */
  int nStatement;               /* Number of nested statement-transactions  */
  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
  i64 nDeferredImmCons;         /* Net deferred immediate constraints */
  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
  DbClientData *pDbData;        /* sqlite3_set_clientdata() content */
#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY

  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[2], &ms) ) return TCL_ERROR;
  rc = sqlite3_busy_timeout(db, ms);
  Tcl_AppendResult(interp, sqlite3ErrName(rc), 0);
  return TCL_OK;
}

/*
** Usage: sqlite3_setlk_timeout ?-blockonconnect? DB MS
**
** Set the setlk timeout.
*/
static int SQLITE_TCLAPI test_setlk_timeout(
  void * clientData,
  Tcl_Interp *interp,
  int argc,
  char **argv
){
  int rc, ms;
  sqlite3 *db;
  int bBlockOnConnect = 0;

  if( argc==4 ){
    const char *zArg = argv[1];
    int nArg = strlen(zArg);
    if( nArg>=2 && nArg<=15 && memcmp(zArg, "-blockonconnect", nArg)==0 ){
      bBlockOnConnect = 1;
    }
  }
  if( argc!=(3+bBlockOnConnect) ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
        " ?-blockonconnect? DB MS", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[argc-2], &db) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[argc-1], &ms) ) return TCL_ERROR;
  rc = sqlite3_setlk_timeout(
      db, ms, (bBlockOnConnect ? SQLITE_SETLK_BLOCK_ON_CONNECT : 0)
  );
  Tcl_AppendResult(interp, sqlite3ErrName(rc), 0);
  return TCL_OK;
}

/*
** Usage:  tcl_variable_type VARIABLENAME
**
** Return the name of the internal representation for the
** value of the given variable.
*/

#if SQLITE_OS_WIN
/*
** Information passed from the main thread into the windows file locker
** background thread.
*/
struct win32FileLocker {
  char *evName;       /* Name of event to signal thread startup */
  sqlite3_file *pFd;  /* Handle of the file to be locked */
  int delay1;         /* Delay before locking */
  int delay2;         /* Delay before unlocking */
  int ok;             /* Finished ok */
  int err;            /* True if an error occurs */
};
#endif


#if SQLITE_OS_WIN
#include <process.h>
/*
** The background thread that does file locking.
*/
static void SQLITE_CDECL win32_file_locker(void *pAppData){
  struct win32FileLocker *p = (struct win32FileLocker*)pAppData;
  sqlite3_file *pFd = p->pFd;
  HANDLE h = INVALID_HANDLE_VALUE;
  if( p->evName ){
    HANDLE ev = OpenEvent(EVENT_MODIFY_STATE, FALSE, p->evName);
    if ( ev ){
      SetEvent(ev);
      CloseHandle(ev);
    }
  }
  if( p->delay1 ) Sleep(p->delay1);
  pFd->pMethods->xFileControl(pFd, SQLITE_FCNTL_WIN32_GET_HANDLE, (void*)&h);
  if( LockFile(h, 0, 0, 100000000, 0) ){
    Sleep(p->delay2);
    UnlockFile(h, 0, 0, 100000000, 0);
    p->ok = 1;
  }else{
    p->err = 1;
  }
  pFd->pMethods->xClose(pFd);
  sqlite3_free(pFd);
  p->pFd = 0;
  p->delay1 = 0;
  p->delay2 = 0;
}
#endif

#if SQLITE_OS_WIN
/*
**      lock_win32_file FILENAME DELAY1 DELAY2
**
** Get an exclusive manditory lock on file for DELAY2 milliseconds.
** Wait DELAY1 milliseconds before acquiring the lock.
*/
static int SQLITE_TCLAPI win32_file_lock(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  static struct win32FileLocker x = { "win32_file_lock", 0, 0, 0, 0, 0 };
  const char *zFilename = 0;
  Tcl_Size nFilename = 0;
  char *zTerm = 0;
  char zBuf[200];
  int retry = 0;
  HANDLE ev;
  DWORD wResult;
  sqlite3_vfs *pVfs = 0;
  int flags = SQLITE_OPEN_MAIN_DB | SQLITE_OPEN_READWRITE;
  int rc = SQLITE_OK;
  
  if( objc!=4 && objc!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, "FILENAME DELAY1 DELAY2");
    return TCL_ERROR;
  }
  if( objc==1 ){
    HANDLE h = INVALID_HANDLE_VALUE;
    if( x.pFd ){
      x.pFd->pMethods->xFileControl(
          x.pFd, SQLITE_FCNTL_WIN32_GET_HANDLE, (void*)&h
      );
    }
    sqlite3_snprintf(sizeof(zBuf), zBuf, "%d %d %d %d %d",
                     x.ok, x.err, x.delay1, x.delay2, h);
    Tcl_AppendResult(interp, zBuf, (char*)0);
    return TCL_OK;
  }
  while( x.pFd && retry<30 ){
    retry++;
    Sleep(100);
  }
  if( x.pFd ){
    Tcl_AppendResult(interp, "busy", (char*)0);
    return TCL_ERROR;
  }
  if( Tcl_GetIntFromObj(interp, objv[2], &x.delay1) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[3], &x.delay2) ) return TCL_ERROR;
  pVfs = sqlite3_vfs_find(0);
  x.pFd = (sqlite3_file*)sqlite3_malloc(pVfs->szOsFile);

  /* xOpen() must be passed a dual-nul-terminated string preceded in memory
  ** by 4 0x00 bytes.  */
  zFilename = Tcl_GetStringFromObj(objv[1], &nFilename);
  zTerm = (char*)sqlite3_malloc(nFilename+6);
  memset(zTerm, 0, nFilename+6);
  memcpy(&zTerm[4], zFilename, nFilename);
  rc = pVfs->xOpen(pVfs, &zTerm[4], x.pFd, flags, &flags);
  sqlite3_free(zTerm);

  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, "cannot open file: ", zFilename, (char*)0);
    return TCL_ERROR;
  }
  ev = CreateEvent(NULL, TRUE, FALSE, x.evName);
  if ( !ev ){
    Tcl_AppendResult(interp, "cannot create event: ", x.evName, (char*)0);
    return TCL_ERROR;

     { "sqlite3_rekey",                 (Tcl_CmdProc*)test_rekey            },
     { "sqlite3_interrupt",             (Tcl_CmdProc*)test_interrupt        },
     { "sqlite3_is_interrupted",        (Tcl_CmdProc*)test_is_interrupted   },
     { "sqlite_delete_function",        (Tcl_CmdProc*)delete_function       },
     { "sqlite_delete_collation",       (Tcl_CmdProc*)delete_collation      },
     { "sqlite3_get_autocommit",        (Tcl_CmdProc*)get_autocommit        },
     { "sqlite3_busy_timeout",          (Tcl_CmdProc*)test_busy_timeout     },
     { "sqlite3_setlk_timeout",         (Tcl_CmdProc*)test_setlk_timeout    },
     { "printf",                        (Tcl_CmdProc*)test_printf           },
     { "sqlite3IoTrace",              (Tcl_CmdProc*)test_io_trace         },
     { "clang_sanitize_address",        (Tcl_CmdProc*)clang_sanitize_address },
  };
  static struct {
     char *zName;
     Tcl_ObjCmdProc *xProc;

#endif

#ifdef SQLITE_WIN32_MALLOC
  Tcl_SetVar2(interp, "sqlite_options", "win32malloc", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "win32malloc", "0", TCL_GLOBAL_ONLY);
#endif

#if defined(SQLITE_OS_WINRT) && SQLITE_OS_WINRT
  Tcl_SetVar2(interp, "sqlite_options", "winrt", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "winrt", "0", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_DEBUG
  Tcl_SetVar2(interp, "sqlite_options", "debug", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "debug", "0", TCL_GLOBAL_ONLY);
#endif

#endif

#ifdef SQLITE_OMIT_WINDOWFUNC
  Tcl_SetVar2(interp, "sqlite_options", "windowfunc", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "windowfunc", "1", TCL_GLOBAL_ONLY);
#endif

#if !defined(SQLITE_ENABLE_SETLK_TIMEOUT)
  Tcl_SetVar2(interp, "sqlite_options", "setlk_timeout", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "setlk_timeout", 
      STRINGVALUE(SQLITE_ENABLE_SETLK_TIMEOUT), TCL_GLOBAL_ONLY);
#endif

#define LINKVAR(x) { \
    static const int cv_ ## x = SQLITE_ ## x; \
    Tcl_LinkVar(interp, "SQLITE_" #x, (char *)&(cv_ ## x), \
                TCL_LINK_INT | TCL_LINK_READ_ONLY); }

  LINKVAR( MAX_LENGTH );

  n = strlen(zUtf8);
  nWide = MultiByteToWideChar(CP_UTF8, 0, zUtf8, -1, NULL, 0);
  if( nWide==0 ) return 0;
  zTmpWide = (LPWSTR)sqlite3_malloc( (nWide+1)*sizeof(zTmpWide[0]) );
  if( zTmpWide==0 ) return 0;
  MultiByteToWideChar(CP_UTF8, 0, zUtf8, -1, zTmpWide, nWide);
#ifdef SQLITE_OS_WINRT
  codepage = CP_ACP;
#else
  codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
#endif
  nMbcs = WideCharToMultiByte(codepage, 0, zTmpWide, nWide, 0, 0, 0, 0);
  zMbcs = nMbcs ? (char*)sqlite3_malloc( nMbcs+1 ) : 0;
  if( zMbcs ){
    WideCharToMultiByte(codepage, 0, zTmpWide, nWide, zMbcs, nMbcs, 0, 0);
  }
  sqlite3_free(zTmpWide);
  return zMbcs;

#define TESTVFS_ACCESS_MASK       0x00004000
#define TESTVFS_FULLPATHNAME_MASK 0x00008000
#define TESTVFS_READ_MASK         0x00010000
#define TESTVFS_UNLOCK_MASK       0x00020000
#define TESTVFS_LOCK_MASK         0x00040000
#define TESTVFS_CKLOCK_MASK       0x00080000
#define TESTVFS_FCNTL_MASK        0x00100000
#define TESTVFS_SLEEP_MASK        0x00200000

#define TESTVFS_ALL_MASK          0x003FFFFF


#define TESTVFS_MAX_PAGES 1024

/*
** A shared-memory buffer. There is one of these objects for each shared
** memory region opened by clients. If two clients open the same file,

}

/*
** Sleep for nMicro microseconds. Return the number of microseconds 
** actually slept.
*/
static int tvfsSleep(sqlite3_vfs *pVfs, int nMicro){
  Testvfs *p = (Testvfs *)pVfs->pAppData;
  if( p->pScript && (p->mask&TESTVFS_SLEEP_MASK) ){
    tvfsExecTcl(p, "xSleep", Tcl_NewIntObj(nMicro), 0, 0, 0);
  }
  return sqlite3OsSleep(PARENTVFS(pVfs), nMicro);
}

/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int tvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){

        { "xClose",             TESTVFS_CLOSE_MASK },
        { "xAccess",            TESTVFS_ACCESS_MASK },
        { "xFullPathname",      TESTVFS_FULLPATHNAME_MASK },
        { "xUnlock",            TESTVFS_UNLOCK_MASK },
        { "xLock",              TESTVFS_LOCK_MASK },
        { "xCheckReservedLock", TESTVFS_CKLOCK_MASK },
        { "xFileControl",       TESTVFS_FCNTL_MASK },
        { "xSleep",             TESTVFS_SLEEP_MASK },
      };
      Tcl_Obj **apElem = 0;
      Tcl_Size nElem = 0;
      int mask = 0;
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "LIST");
        return TCL_ERROR;

#define walFrameOffset(iFrame, szPage) (                               \
  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
)

/*
** An open write-ahead log file is represented by an instance of the
** following object.
**
** writeLock:
**   This is usually set to 1 whenever the WRITER lock is held. However,
**   if it is set to 2, then the WRITER lock is held but must be released
**   by walHandleException() if a SEH exception is thrown.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */

** they are supported by the VFS, and (b) the database handle is configured
** with a busy-timeout. Return 1 if blocking locks are successfully enabled,
** or 0 otherwise.
*/
static int walEnableBlocking(Wal *pWal){
  int res = 0;
  if( pWal->db ){
    int tmout = pWal->db->setlkTimeout;
    if( tmout ){
      res = walEnableBlockingMs(pWal, tmout);
    }
  }
  return res;
}

**   4) Returns SQLITE_IOERR.
*/
static int walHandleException(Wal *pWal){
  if( pWal->exclusiveMode==0 ){
    static const int S = 1;
    static const int E = (1<<SQLITE_SHM_NLOCK);
    int ii;
    u32 mUnlock;
    if( pWal->writeLock==2 ) pWal->writeLock = 0;
    mUnlock = pWal->lockMask & ~(
        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
        | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
        | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
        );
    for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
      if( (S<<ii) & mUnlock ) walUnlockShared(pWal, ii);
      if( (E<<ii) & mUnlock ) walUnlockExclusive(pWal, ii, 1);

        rc = SQLITE_READONLY_RECOVERY;
      }
    }else{
      int bWriteLock = pWal->writeLock;
      if( bWriteLock 
       || SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1)) 
      ){
        /* If the write-lock was just obtained, set writeLock to 2 instead of
        ** the usual 1. This causes walIndexPage() to behave as if the 
        ** write-lock were held (so that it allocates new pages as required),
        ** and walHandleException() to unlock the write-lock if a SEH exception
        ** is thrown.  */
        if( !bWriteLock ) pWal->writeLock = 2;
        if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
          badHdr = walIndexTryHdr(pWal, pChanged);
          if( badHdr ){
            /* If the wal-index header is still malformed even while holding
            ** a WRITE lock, it can only mean that the header is corrupted and
            ** needs to be reconstructed.  So run recovery to do exactly that.
            ** Disable blocking locks first.  */

}

/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/
void sqlite3WalEndReadTransaction(Wal *pWal){
#ifndef SQLITE_ENABLE_SETLK_TIMEOUT
  assert( pWal->writeLock==0 || pWal->readLock<0 );
#endif
  if( pWal->readLock>=0 ){
    sqlite3WalEndWriteTransaction(pWal);
    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
    pWal->readLock = -1;
  }
}

/*
** Search the wal file for page pgno. If found, set *piRead to the frame that

  int rc;

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  /* If the write-lock is already held, then it was obtained before the
  ** read-transaction was even opened, making this call a no-op.
  ** Return early. */
  if( pWal->writeLock ){
    assert( !memcmp(&pWal->hdr,(void*)pWal->apWiData[0],sizeof(WalIndexHdr)) );
    return SQLITE_OK;
  }
#endif

  /* Cannot start a write transaction without first holding a read
  ** transaction. */
  assert( pWal->readLock>=0 );

  file_control_lasterrno_test db
} {}
do_test filectrl-1.5 {
  db close
  sqlite3 db test_control_lockproxy.db
  file_control_lockproxy_test db [get_pwd]
} {}
ifcapable !winrt {
  do_test filectrl-1.6 {
    sqlite3 db test.db
    set fn [file_control_tempfilename db]
    set fn
  } {/etilqs_/}
}
db close
forcedelete .test_control_lockproxy.db-conch test.proxy
forcedelete test.db test2.db

if {$tcl_platform(platform)=="windows"} {
  do_test filectrl-2.1 {
    sqlite3 db test2.db

    append ::tfnb($chan) "ERROR: Child process hung up"
    set line "OVER"
  } else {
    set line [gets $chan]
  }

  if { $line == "OVER" } {
    global $varname
    set $varname [lindex $::tfnb($chan) 1]
    unset ::tfnb($chan)
    close $chan
  } else {
    append ::tfnb($chan) $line
  }
}

  catchcmd "test.db" ".bail OFF"
} {0 {}}
do_test shell1-3.2.4 {
  # too many arguments
  catchcmd "test.db" ".bail OFF BAD"
} {1 {Usage: .bail on|off}}

# This test will not work on winrt, as winrt has no concept of the absolute
# paths that the test expects in the result. It uses relative paths only.
ifcapable vtab&&!winrt {
# .databases             List names and files of attached databases
do_test shell1-3.3.1 {
  catchcmd "-csv test.db" ".databases"
} "/0.+main.+[string map {/ ".{1,2}"} [string range [get_pwd] 0 10]].*/"
do_test shell1-3.3.2 {
  # extra arguments ignored
  catchcmd "test.db" ".databases BAD"

} {0 {   abcdefg  123456    }}


# .timer ON|OFF          Turn the CPU timer measurement on or off
do_test shell1-3.27.1 {
  catchcmd "test.db" ".timer"
} {1 {Usage: .timer on|off}}
ifcapable !winrt {
  # No timer support on winrt.
  do_test shell1-3.27.2 {
    catchcmd "test.db" ".timer ON"
  } {0 {}}
}
do_test shell1-3.27.3 {
  catchcmd "test.db" ".timer OFF"
} {0 {}}
do_test shell1-3.27.4 {
  # too many arguments
  catchcmd "test.db" ".timer OFF BAD"
} {1 {Usage: .timer on|off}}

    error "Compulsory option -file missing"
  }

  # $crashfile gets compared to the native filename in
  # cfSync(), which can be different then what TCL uses by
  # default, so here we force it to the "nativename" format.
  set cfile [string map {\\ \\\\} [file nativename [file join [get_pwd] $crashfile]]]
  ifcapable winrt {
    # Except on winrt. Winrt has no way to transform a relative path into
    # an absolute one, so it just uses the relative paths.
    set cfile $crashfile
  }

  set f [open crash.tcl w]
  puts $f "sqlite3_initialize ; sqlite3_shutdown"
  puts $f "catch { install_malloc_faultsim 1 }"
  puts $f "sqlite3_crash_enable 1 $dfltvfs"
  puts $f "sqlite3_crashparams $blocksize $dc $crashdelay $cfile"
  puts $f "sqlite3_test_control_pending_byte $::sqlite_pending_byte"

  set tcltest(osx.Apple)                  all_less_no_mutex_try

  set tcltest(win.Stdcall)                veryquick
  set tcltest(win.Have-Not)               veryquick
  set tcltest(win.Windows-Memdebug)       veryquick
  set tcltest(win.Windows-Win32Heap)      veryquick
  set tcltest(win.Windows-Sanitize)       veryquick
  set tcltest(win.Windows-WinRT)          veryquick
  set tcltest(win.Default)                full

  # Extra [make xyz] tests that should be run for various builds.
  #
  set extra(linux.Check-Symbols)          checksymbols
  set extra(linux.Fast-One)               {fuzztest sourcetest}
  set extra(linux.Debug-One)              {fuzztest sourcetest mptest}

  set build(Windows-Memdebug) {
    MEMDEBUG=1
    DEBUG=3
  }
  set build(Windows-Win32Heap) {
    WIN32HEAP=1
    DEBUG=4
    ENABLE_SETLK=1
  }
  set build(Windows-Sanitize) {
    ASAN=1
  }

  set build(Windows-WinRT) {
    FOR_WINRT=1
    ENABLE_SETLK=1
    -DSQLITE_TEMP_STORE=3
  }
}


#-------------------------------------------------------------------------
proc trd_import {} {
  uplevel {
    variable ::trd::tcltest

close $fd
db close
db2 close
#-------------------------------------------------------------------------

do_multiclient_test tn {

  testvfs tvfs -fullshm 1
  db close
  sqlite3 db test.db -vfs tvfs
  tvfs script xSleep_callback
  tvfs filter xSleep

  set ::sleep_count 0
  proc xSleep_callback {xSleep nMs} {
    after [expr $nMs / 1000]
    incr ::sleep_count
  }

  do_test 2.$tn.1 {
    sql1 {
      PRAGMA journal_mode = wal;
      CREATE TABLE t1(s, v);
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
      INSERT INTO t1 VALUES(5, 6);

    }
  } {1 2 3 4 5 6 7 8 9 10}

  do_test 2.$tn.8 {
    set us [lindex [time { catch {db eval "PRAGMA wal_checkpoint=RESTART"} }] 0]
    expr $us>1000000 && $us<4000000
  } {1}

  do_test 2.$tn.9 {
    sql3 {
      INSERT INTO t1 VALUES(11, 12);
    }
    sql2 {
      COMMIT;
      BEGIN;

    sql1 { INSERT INTO t1 VALUES(17, 18); }
  } {}

  do_test 2.$tn.14 {
    set us [lindex [time { catch {db eval "PRAGMA wal_checkpoint=RESTART"} }] 0]
    expr $us>1000000 && $us<4000000
  } {1}

  db close
  tvfs delete

  # Set bSleep to true if it is expected that the above used xSleep() to
  # wait for locks. bSleep is true unless SQLITE_ENABLE_SETLK_TIMEOUT is
  # set to 1 and either:
  #
  #   * the OS is windows, or
  #   * the OS is unix and the tests were run with each connection 
  #     in a separate process.
  #
  set bSleep 1
  if {$::sqlite_options(setlk_timeout)==1} {
    if {$::tcl_platform(platform)=="windows"} {
      set bSleep 0
    }
    if {$::tcl_platform(platform)=="unix"} {
      set bSleep [expr $tn==2]
    }
  }

  do_test 2.$tn.15.$bSleep {
    expr $::sleep_count > 0
  } $bSleep
}

#-------------------------------------------------------------------------
reset_db

testvfs tvfs -fullshm 1
tvfs script xSleep_callback
tvfs filter xSleep

set ::sleep_count 0
proc xSleep_callback {xSleep nMs} {
  after [expr $nMs / 1000]
  incr ::sleep_count
  breakpoint
}

sqlite3 db2 test.db -vfs tvfs
db2 timeout 1000

do_execsql_test 3.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE x1(x, y);
  BEGIN;
    INSERT INTO x1 VALUES(1, 2);
} {wal}

do_execsql_test -db db2 3.1a {
  SELECT * FROM x1
} {}

do_test 3.1b {
  list [catch { db2 eval {BEGIN EXCLUSIVE} } msg] $msg
} {1 {database is locked}}

# Set bExpect to true if calls to xSleep() are expected. Such calls are
# expected unless this is an SQLITE_ENABLE_SETLK_TIMEOUT=1 build.
set bExpect 1
if {$tcl_platform(platform)=="windows" && $::sqlite_options(setlk_timeout)==1} {
  set bExpect 0
}
do_test 3.2 {
  expr {$::sleep_count > 0}
} $bExpect
set ::sleep_count 0

do_execsql_test 3.3 {
  COMMIT;
}

# Launch a non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
     INSERT INTO x1 VALUES(3, 4);
  }
  after 2000
  db eval {
    COMMIT
  }
}

after 500 {set ok 1}
vwait ok

db2 timeout 5000
do_test 3.4 {
  set t [lindex [time { db2 eval { BEGIN EXCLUSIVE } }] 0]
  expr ($t>1000000)
} {1}

# Set bExpect to true if calls to xSleep() are expected. Such calls are
# expected unless this is an SQLITE_ENABLE_SETLK_TIMEOUT=1 build.
set bExpect 1
if {$::sqlite_options(setlk_timeout)==1} {
  set bExpect 0
}
do_test 3.5 {
  expr {$::sleep_count > 0}
} $bExpect

do_execsql_test -db db2 3.6 {
  INSERT INTO x1 VALUES(5, 6);
  COMMIT;
  SELECT * FROM x1;
} {1 2 3 4 5 6}

# Launch a non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
     INSERT INTO x1 VALUES(7, 8);
  }
  after 2000
  db eval {
    COMMIT
  }
}

after 500 {set ok 1}
vwait ok

db2 timeout 0x7FFFFFFF
do_test 3.7 {
  set t [lindex [time { db2 eval { BEGIN EXCLUSIVE } }] 0]
  expr ($t>1000000)
} {1}

# Set bExpect to true if calls to xSleep() are expected. Such calls are
# expected unless this is an SQLITE_ENABLE_SETLK_TIMEOUT=1 build.
set bExpect 1
if {$::sqlite_options(setlk_timeout)==1} {
  set bExpect 0
}
do_test 3.8 {
  expr {$::sleep_count > 0}
} $bExpect

do_execsql_test -db db2 3.9 {
  INSERT INTO x1 VALUES(9, 10);
  COMMIT;
  SELECT * FROM x1;
} {1 2 3 4 5 6 7 8 9 10}

db2 close
tvfs delete

finish_test

# 2025 Jan 24
#
# 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.
#
#***********************************************************************
#
# TESTRUNNER: slow
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
set testprefix walsetlk2

ifcapable !wal {finish_test ; return }
ifcapable !setlk_timeout {finish_test ; return }

#-------------------------------------------------------------------------
# Check that xShmLock calls are as expected for write transactions in
# setlk mode.
#
reset_db

do_execsql_test 1.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(a, b, c);
  INSERT INTO t1 VALUES(1, 2, 3);
} {wal}
db close

testvfs tvfs
tvfs script xShmLock_callback
tvfs filter xShmLock

set ::xshmlock [list]
proc xShmLock_callback {method path name detail} {
  lappend ::xshmlock $detail
}

sqlite3 db test.db -vfs tvfs
db timeout 1000

do_execsql_test 1.1 {
  SELECT * FROM t1
} {1 2 3}

do_execsql_test 1.2 {
  INSERT INTO t1 VALUES(4, 5, 6);
}

set ::xshmlock [list]
do_execsql_test 1.3 {
  INSERT INTO t1 VALUES(7, 8, 9);
}

do_test 1.4 {
  set ::xshmlock
} [list \
  {0 1 lock exclusive}                             \
  {4 1 lock exclusive} {4 1 unlock exclusive}      \
  {4 1 lock shared}                                \
  {0 1 unlock exclusive}                           \
  {4 1 unlock shared}
]

do_execsql_test 1.5.1 { SELECT * FROM t1 } {1 2 3 4 5 6 7 8 9}
set ::xshmlock [list]
do_execsql_test 1.5.2 {
  INSERT INTO t1 VALUES(10, 11, 12);
}
do_test 1.5.3 {
  set ::xshmlock
} [list \
  {0 1 lock exclusive}                             \
  {4 1 lock shared}                                \
  {0 1 unlock exclusive}                           \
  {4 1 unlock shared}
]

db close
tvfs delete

#-------------------------------------------------------------------------
# Check that if sqlite3_setlk_timeout() is used, blocking locks timeout
# but other operations do not use the retry mechanism.
#
reset_db

do_execsql_test 2.0 {
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2), (3, 4);
}

sqlite3_setlk_timeout db 2000

# Launch a non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
      INSERT INTO t1 VALUES(5, 6);
  }
  after 2000
  db eval {
    COMMIT
  }
  db close
}

after 500 {set ok 1}
vwait ok

do_catchsql_test 2.1 {
  INSERT INTO t1 VALUES(7, 8);
} {1 {database is locked}}

sqlite3_busy_timeout db 2000

do_catchsql_test 2.2 {
  INSERT INTO t1 VALUES(7, 8);
} {0 {}}

do_execsql_test 2.3 {
  SELECT * FROM t1
} {1 2 3 4 5 6 7 8}

do_execsql_test 2.4 {
  PRAGMA journal_mode = wal;
} {wal}

db close
sqlite3 db test.db

do_execsql_test 2.5 {
  INSERT INTO t1 VALUES(9, 10);
}

sqlite3_setlk_timeout db 2000

# Launch a non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
      INSERT INTO t1 VALUES(11, 12);
  }
  after 2000
  db eval {
    COMMIT
  }
  db close
}

after 500 {set ok 1}
vwait ok

do_catchsql_test 2.6 {
  INSERT INTO t1 VALUES(13, 14);
} {0 {}}

do_execsql_test 2.7 {
  SELECT * FROM t1
} {1 2 3 4 5 6 7 8 9 10 11 12 13 14}

#-------------------------------------------------------------------------
# Check that if sqlite3_setlk_timeout(-1) is called, blocking locks are
# enabled and last for a few seconds at least. Difficult to test that they
# really do block indefinitely.
#
reset_db

do_execsql_test 3.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  INSERT INTO t1 VALUES(1, 'one'), (3, 'three');
} {wal}

sqlite3_setlk_timeout db -1

# Launch a non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
      INSERT INTO t1 VALUES(5, 'five');
  }
  after 2000
  db eval {
    COMMIT
  }
  db close
}

after 500 {set ok 1}
vwait ok

breakpoint
do_catchsql_test 3.1 {
  INSERT INTO t1 VALUES(7, 'seven');
} {0 {}}

# Launch another non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
      INSERT INTO t1 VALUES(9, 'nine');
  }
  after 2000
  db eval {
    COMMIT
  }
  db close
}

after 500 {set ok 1}
vwait ok

do_catchsql_test 3.2 {
  INSERT INTO t1 VALUES(9, 'ten');
} {1 {UNIQUE constraint failed: t1.a}}

do_execsql_test 3.3 {
  SELECT * FROM t1
} {1 one 3 three 5 five 7 seven 9 nine}

db close

# Launch another non-blocking testfixture process to write-lock the 
# database for 2000 ms.
testfixture_nb done {
  sqlite3 db test.db
  db eval {
    BEGIN EXCLUSIVE;
      INSERT INTO t1 VALUES(11, 'eleven');
  }
  after 2000
  db eval {
    COMMIT
  }
}

sqlite3 db test.db
sqlite3_setlk_timeout db -1
do_catchsql_test 3.4 {
  INSERT INTO t1 VALUES(13, 'thirteen');
} {0 {}}


finish_test

# 2020 May 06
#
# 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.
#
#***********************************************************************
#
# TESTRUNNER: slow
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
set testprefix walsetlk3

ifcapable !wal {finish_test ; return }
ifcapable !setlk_timeout {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(x, y);
  PRAGMA journal_mode = wal;
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
} {wal}

db close

proc sql_block_on_close {sql} {
  testfixture_nb done [string map [list %SQL% $sql] {
    testvfs tvfs
    tvfs script xWrite
    tvfs filter xWrite
  
    set ::delay_done 0
    proc xWrite {method fname args} {
      if {[file tail $fname]=="test.db" && $::delay_done==0} {
        after 3000
        set ::delay_done 1
      }
      return 0
    }
  
    sqlite3 db test.db -vfs tvfs
    db eval {%SQL%}
    db close
  }]
}

# Start a second process that writes to the db, then blocks within the
# [db close] holding an EXCLUSIVE on the db in order to checkpoint and 
# delete the wal file. Then try to read the db.
#
# Without the SQLITE_SETLK_BLOCK_ON_CONNECT flag, this should fail with
# SQLITE_BUSY.
#
sql_block_on_close {
  INSERT INTO t1 VALUES(5, 6);
  INSERT INTO t1 VALUES(7, 8);
}
after 500 {set ok 1}
vwait ok
sqlite3 db test.db
sqlite3_setlk_timeout db 2000
do_catchsql_test 1.1 {
  SELECT * FROM t1
} {1 {database is locked}}

vwait ::done

# But with SQLITE_SETLK_BLOCK_ON_CONNECT flag, it should succeed.
#
sql_block_on_close {
  INSERT INTO t1 VALUES(9, 10);
  INSERT INTO t1 VALUES(11, 12);
}
after 500 {set ok 1}
vwait ok
sqlite3 db test.db
sqlite3_setlk_timeout -block db 2000
do_catchsql_test 1.2 {
  SELECT * FROM t1
} {0 {1 2 3 4 5 6 7 8 9 10 11 12}}

vwait ::done

#-------------------------------------------------------------------------
# Check that the SQLITE_SETLK_BLOCK_ON_CONNECT does not cause connections
# to block when taking a SHARED lock on a rollback mode database.
#
reset_db
do_execsql_test 2.1 {
  CREATE TABLE x1(a);
  INSERT INTO x1 VALUES(1), (2), (3);
}

proc sql_block_on_write {sql} {
  testfixture_nb done [string map [list %SQL% $sql] {
    sqlite3 db test.db 
    db eval "BEGIN EXCLUSIVE"
    db eval {%SQL%}
    after 3000
    db eval COMMIT
    db close
  }]
}

db close
sql_block_on_write {
  INSERT INTO x1 VALUES(4);
}

after 500 {set ok 1}
vwait ok

sqlite3 db test.db
sqlite3_setlk_timeout -block db 2000

do_catchsql_test 2.2 {
  SELECT * FROM x1
} {1 {database is locked}}

vwait ::done
after 500 {set ok 1}
vwait ok

do_catchsql_test 2.3 {
  SELECT * FROM x1
} {0 {1 2 3 4}}

finish_test

    SELECT x FROM t1 ORDER BY x;
    COMMIT;
  }
} {5 6 7 8 9 10 11 12}

db3 close

# winrt platforms do not handle paths with unix-style '/' directory separators.
#
set lUri [list 1a 1b 1c 1d 1e 1f]
ifcapable winrt { set lUri [list 1a 1c 1e] }

foreach tn $lUri {
  sqlite3 db3 $uri($tn) -vfs win32-longpath -uri 1 -translatefilename 0

  do_test 1.7.$tn {
    db3 eval {
      SELECT x FROM t1 ORDER BY x;
    }
  } {5 6 7 8 9 10 11 12}

  SQLITE_ENABLE_OFFSET_SQL_FUNC
  SQLITE_ENABLE_OVERSIZE_CELL_CHECK
  SQLITE_ENABLE_PREUPDATE_HOOK
  SQLITE_ENABLE_QPSG
  SQLITE_ENABLE_RBU
  SQLITE_ENABLE_RTREE
  SQLITE_ENABLE_SESSION
  SQLITE_ENABLE_SETLK_TIMEOUT
  SQLITE_ENABLE_SNAPSHOT
  SQLITE_ENABLE_SORTER_REFERENCES
  SQLITE_ENABLE_SQLLOG
  SQLITE_ENABLE_STAT4
  SQLITE_ENABLE_STMT_SCANSTATUS
  SQLITE_ENABLE_STMTVTAB
  SQLITE_ENABLE_TREETRACE