os_win.c

最新的sqlite3.6.2源代码

    isTemp = 1;
  }else{
    dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
    isTemp = 0;
  }
  /* Reports from the internet are that performance is always
  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
  if( isNT() ){
    h = CreateFileW((WCHAR*)zConverted,
       dwDesiredAccess,
       dwShareMode,
       NULL,
       dwCreationDisposition,
       dwFlagsAndAttributes,
       NULL
    );
  }else{
    h = CreateFileA((char*)zConverted,
       dwDesiredAccess,
       dwShareMode,
       NULL,
       dwCreationDisposition,
       dwFlagsAndAttributes,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    free(zConverted);
    if( flags & SQLITE_OPEN_READWRITE ){
      return winOpen(0, zName, id, 
             ((flags|SQLITE_OPEN_READONLY)&~SQLITE_OPEN_READWRITE), pOutFlags);
    }else{
      return SQLITE_CANTOPEN;
    }
  }
  if( pOutFlags ){
    if( flags & SQLITE_OPEN_READWRITE ){
      *pOutFlags = SQLITE_OPEN_READWRITE;
    }else{
      *pOutFlags = SQLITE_OPEN_READONLY;
    }
  }
  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
#if SQLITE_OS_WINCE
  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
       && !winceCreateLock(zName, pFile)
  ){
    CloseHandle(h);
    free(zConverted);
    return SQLITE_CANTOPEN;
  }
  if( isTemp ){
    pFile->zDeleteOnClose = zConverted;
  }else
#endif
  {
    free(zConverted);
  }
  OpenCounter(+1);
  return SQLITE_OK;
}

/*
** Delete the named file.
**
** Note that windows does not allow a file to be deleted if some other
** process has it open.  Sometimes a virus scanner or indexing program
** will open a journal file shortly after it is created in order to do
** whatever it does.  While this other process is holding the
** file open, we will be unable to delete it.  To work around this
** problem, we delay 100 milliseconds and try to delete again.  Up
** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
** up and returning an error.
*/
#define MX_DELETION_ATTEMPTS 5
static int winDelete(
  sqlite3_vfs *pVfs,          /* Not used on win32 */
  const char *zFilename,      /* Name of file to delete */
  int syncDir                 /* Not used on win32 */
){
  int cnt = 0;
  int rc;
  DWORD error;
  void *zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_NOMEM;
  }
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( isNT() ){
    do{
      DeleteFileW(zConverted);
    }while(   (   ((rc = GetFileAttributesW(zConverted)) != INVALID_FILE_ATTRIBUTES)
               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
           && (cnt++ < MX_DELETION_ATTEMPTS)
           && (Sleep(100), 1) );
  }else{
    do{
      DeleteFileA(zConverted);
    }while(   (   ((rc = GetFileAttributesA(zConverted)) != INVALID_FILE_ATTRIBUTES)
               || ((error = GetLastError()) == ERROR_ACCESS_DENIED))
           && (cnt++ < MX_DELETION_ATTEMPTS)
           && (Sleep(100), 1) );
  }
  free(zConverted);
  OSTRACE2("DELETE \"%s\"\n", zFilename);
  return (   (rc==INVALID_FILE_ATTRIBUTES) 
          && (error == ERROR_FILE_NOT_FOUND)) ? SQLITE_OK : SQLITE_IOERR_DELETE;
}

/*
** Check the existance and status of a file.
*/
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){
  DWORD attr;
  int rc;
  void *zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_NOMEM;
  }
  if( isNT() ){
    attr = GetFileAttributesW((WCHAR*)zConverted);
  }else{
    attr = GetFileAttributesA((char*)zConverted);
  }
  free(zConverted);
  switch( flags ){
    case SQLITE_ACCESS_READ:
    case SQLITE_ACCESS_EXISTS:
      rc = attr!=INVALID_FILE_ATTRIBUTES;
      break;
    case SQLITE_ACCESS_READWRITE:
      rc = (attr & FILE_ATTRIBUTE_READONLY)==0;
      break;
    default:
      assert(!"Invalid flags argument");
  }
  *pResOut = rc;
  return SQLITE_OK;
}


/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
** bytes in size.
*/
static int winFullPathname(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zRelative,        /* Possibly relative input path */
  int nFull,                    /* Size of output buffer in bytes */
  char *zFull                   /* Output buffer */
){

#if defined(__CYGWIN__)
  cygwin_conv_to_full_win32_path(zRelative, zFull);
  return SQLITE_OK;
#endif

#if SQLITE_OS_WINCE
  /* WinCE has no concept of a relative pathname, or so I am told. */
  sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zRelative);
  return SQLITE_OK;
#endif

#if !SQLITE_OS_WINCE && !defined(__CYGWIN__)
  int nByte;
  void *zConverted;
  char *zOut;
  zConverted = convertUtf8Filename(zRelative);
  if( isNT() ){
    WCHAR *zTemp;
    nByte = GetFullPathNameW((WCHAR*)zConverted, 0, 0, 0) + 3;
    zTemp = malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      free(zConverted);
      return SQLITE_NOMEM;
    }
    GetFullPathNameW((WCHAR*)zConverted, nByte, zTemp, 0);
    free(zConverted);
    zOut = unicodeToUtf8(zTemp);
    free(zTemp);
  }else{
    char *zTemp;
    nByte = GetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
    zTemp = malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      free(zConverted);
      return SQLITE_NOMEM;
    }
    GetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
    free(zConverted);
    zOut = mbcsToUtf8(zTemp);
    free(zTemp);
  }
  if( zOut ){
    sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zOut);
    free(zOut);
    return SQLITE_OK;
  }else{
    return SQLITE_NOMEM;
  }
#endif
}

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
  HANDLE h;
  void *zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return 0;
  }
  if( isNT() ){
    h = LoadLibraryW((WCHAR*)zConverted);
  }else{
    h = LoadLibraryA((char*)zConverted);
  }
  free(zConverted);
  return (void*)h;
}
static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
  getLastErrorMsg(nBuf, zBufOut);
}
void *winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
#if SQLITE_OS_WINCE
  /* The GetProcAddressA() routine is only available on wince. */
  return GetProcAddressA((HANDLE)pHandle, zSymbol);
#else
  /* All other windows platforms expect GetProcAddress() to take
  ** an Ansi string regardless of the _UNICODE setting */
  return GetProcAddress((HANDLE)pHandle, zSymbol);
#endif
}
void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
  FreeLibrary((HANDLE)pHandle);
}
#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
  #define winDlOpen  0
  #define winDlError 0
  #define winDlSym   0
  #define winDlClose 0
#endif


/*
** Write up to nBuf bytes of randomness into zBuf.
*/
static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  int n = 0;
  if( sizeof(SYSTEMTIME)<=nBuf-n ){
    SYSTEMTIME x;
    GetSystemTime(&x);
    memcpy(&zBuf[n], &x, sizeof(x));
    n += sizeof(x);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD pid = GetCurrentProcessId();
    memcpy(&zBuf[n], &pid, sizeof(pid));
    n += sizeof(pid);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD cnt = GetTickCount();
    memcpy(&zBuf[n], &cnt, sizeof(cnt));
    n += sizeof(cnt);
  }
  if( sizeof(LARGE_INTEGER)<=nBuf-n ){
    LARGE_INTEGER i;
    QueryPerformanceCounter(&i);
    memcpy(&zBuf[n], &i, sizeof(i));
    n += sizeof(i);
  }
  return n;
}


/*
** Sleep for a little while.  Return the amount of time slept.
*/
static int winSleep(sqlite3_vfs *pVfs, int microsec){
  Sleep((microsec+999)/1000);
  return ((microsec+999)/1000)*1000;
}

/*
** The following variable, if set to a non-zero value, becomes the result
** returned from sqlite3OsCurrentTime().  This is used for testing.
*/
#ifdef SQLITE_TEST
int sqlite3_current_time = 0;
#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.
*/
int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
  FILETIME ft;
  /* FILETIME structure is a 64-bit value representing the number of 
     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). 
  */
  double now;
#if SQLITE_OS_WINCE
  SYSTEMTIME time;
  GetSystemTime(&time);
  /* if SystemTimeToFileTime() fails, it returns zero. */
  if (!SystemTimeToFileTime(&time,&ft)){
    return 1;
  }
#else
  GetSystemTimeAsFileTime( &ft );
#endif
  now = ((double)ft.dwHighDateTime) * 4294967296.0; 
  *prNow = (now + ft.dwLowDateTime)/864000000000.0 + 2305813.5;
#ifdef SQLITE_TEST
  if( sqlite3_current_time ){
    *prNow = sqlite3_current_time/86400.0 + 2440587.5;
  }
#endif
  return 0;
}

/*
** The idea is that this function works like a combination of
** GetLastError() and FormatMessage() on windows (or errno and
** strerror_r() on unix). After an error is returned by an OS
** function, SQLite calls this function with zBuf pointing to
** a buffer of nBuf bytes. The OS layer should populate the
** buffer with a nul-terminated UTF-8 encoded error message
** describing the last IO error to have occured within the calling
** thread.
**
** If the error message is too large for the supplied buffer,
** it should be truncated. The return value of xGetLastError
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated). If non-zero is returned,
** then it is not necessary to include the nul-terminator character
** in the output buffer.
**
** Not supplying an error message will have no adverse effect
** on SQLite. It is fine to have an implementation that never
** returns an error message:
**
**   int xGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
**     assert(zBuf[0]=='\0');
**     return 0;
**   }
**
** However if an error message is supplied, it will be incorporated
** by sqlite into the error message available to the user using
** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  return getLastErrorMsg(nBuf, zBuf);
}

/*
** 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 */
  };
  sqlite3_vfs_register(&winVfs, 1);
  return SQLITE_OK; 
}
int sqlite3_os_end(void){ 
  return SQLITE_OK;
}

#endif /* SQLITE_OS_WIN */