os_win.c

pda上的数据库,速度快,体积小,做朋友的福音

/*
** 2004 May 22
**
** 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.
**
******************************************************************************
**
** This file contains code that is specific to windows.
*/
#include "sqliteInt.h"
#include "os.h"
#if OS_WIN               /* This file is used for windows only */

#include <winbase.h>

#ifdef __CYGWIN__
# include <sys/cygwin.h>
#endif

/*
** Macros used to determine whether or not to use threads.
*/
#if defined(THREADSAFE) && THREADSAFE
# define SQLITE_W32_THREADS 1
#endif

/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
** Do not include any of the File I/O interface procedures if the
** SQLITE_OMIT_DISKIO macro is defined (indicating that there database
** will be in-memory only)
*/
#ifndef SQLITE_OMIT_DISKIO

/*
** The following variable is (normally) set once and never changes
** thereafter.  It records whether the operating system is Win95
** or WinNT.
**
** 0:   Operating system unknown.
** 1:   Operating system is Win95.
** 2:   Operating system is WinNT.
**
** In order to facilitate testing on a WinNT system, the test fixture
** can manually set this value to 1 to emulate Win98 behavior.
*/
int sqlite3_os_type = 0;

/*
** Return true (non-zero) if we are running under WinNT, Win2K or WinXP.
** Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
** the LockFileEx() API.  But we can still statically link against that
** API as long as we don't call it win running Win95/98/ME.  A call to
** this routine is used to determine if the host is Win95/98/ME or
** WinNT/2K/XP so that we will know whether or not we can safely call
** the LockFileEx() API.
*/
static int isNT(void){
  if( sqlite3_os_type==0 ){
    OSVERSIONINFO sInfo;
    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
    GetVersionEx(&sInfo);
    sqlite3_os_type = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
  }
  return sqlite3_os_type==2;
}

/*
** Convert a UTF-8 string to UTF-32.  Space to hold the returned string
** is obtained from sqliteMalloc.
*/
static WCHAR *utf8ToUnicode(const char *zFilename){
  int nByte;
  WCHAR *zWideFilename;

  if( !isNT() ){
    return 0;
  }
  nByte = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0)*sizeof(WCHAR);
  zWideFilename = sqliteMalloc( nByte*sizeof(zWideFilename[0]) );
  if( zWideFilename==0 ){
    return 0;
  }
  nByte = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename, nByte);
  if( nByte==0 ){
    sqliteFree(zWideFilename);
    zWideFilename = 0;
  }
  return zWideFilename;
}

/*
** Convert UTF-32 to UTF-8.  Space to hold the returned string is
** obtained from sqliteMalloc().
*/
static char *unicodeToUtf8(const WCHAR *zWideFilename){
  int nByte;
  char *zFilename;

  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
  zFilename = sqliteMalloc( nByte );
  if( zFilename==0 ){
    return 0;
  }
  nByte = WideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
                              0, 0);
  if( nByte == 0 ){
    sqliteFree(zFilename);
    zFilename = 0;
  }
  return zFilename;
}


/*
** Delete the named file
*/
int sqlite3OsDelete(const char *zFilename){
  WCHAR *zWide = utf8ToUnicode(zFilename);
  if( zWide ){
    DeleteFileW(zWide);
    sqliteFree(zWide);
  }else{
    DeleteFileA(zFilename);
  }
  TRACE2("DELETE \"%s\"\n", zFilename);
  return SQLITE_OK;
}

/*
** Return TRUE if the named file exists.
*/
int sqlite3OsFileExists(const char *zFilename){
  int exists = 0;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  if( zWide ){
    exists = GetFileAttributesW(zWide) != 0xffffffff;
    sqliteFree(zWide);
  }else{
    exists = GetFileAttributesA(zFilename) != 0xffffffff;
  }
  return exists;
}

/*
** Attempt to open a file for both reading and writing.  If that
** fails, try opening it read-only.  If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
** and *pReadonly is set to 0 if the file was opened for reading and
** writing or 1 if the file was opened read-only.  The function returns
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
int sqlite3OsOpenReadWrite(
  const char *zFilename,
  OsFile *id,
  int *pReadonly
){
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ | GENERIC_WRITE,
       FILE_SHARE_READ | FILE_SHARE_WRITE,
       NULL,
       OPEN_ALWAYS,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
    if( h==INVALID_HANDLE_VALUE ){
      h = CreateFileW(zWide,
         GENERIC_READ,
         FILE_SHARE_READ,
         NULL,
         OPEN_ALWAYS,
         FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
         NULL
      );
      if( h==INVALID_HANDLE_VALUE ){
        sqliteFree(zWide);
        return SQLITE_CANTOPEN;
      }
      *pReadonly = 1;
    }else{
      *pReadonly = 0;
    }
    sqliteFree(zWide);
  }else{
    h = CreateFileA(zFilename,
       GENERIC_READ | GENERIC_WRITE,
       FILE_SHARE_READ | FILE_SHARE_WRITE,
       NULL,
       OPEN_ALWAYS,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
    if( h==INVALID_HANDLE_VALUE ){
      h = CreateFileA(zFilename,
         GENERIC_READ,
         FILE_SHARE_READ,
         NULL,
         OPEN_ALWAYS,
         FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
         NULL
      );
      if( h==INVALID_HANDLE_VALUE ){
        return SQLITE_CANTOPEN;
      }
      *pReadonly = 1;
    }else{
      *pReadonly = 0;
    }
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;
  OpenCounter(+1);
  TRACE3("OPEN R/W %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid
** a potential security problem, we do not allow the file to have
** previously existed.  Nor do we allow the file to be a symbolic
** link.
**
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
int sqlite3OsOpenExclusive(const char *zFilename, OsFile *id, int delFlag){
  HANDLE h;
  int fileflags;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 
                     | FILE_FLAG_DELETE_ON_CLOSE;
  }else{
    fileflags = FILE_FLAG_RANDOM_ACCESS;
  }
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ | GENERIC_WRITE,
       0,
       NULL,
       CREATE_ALWAYS,
       fileflags,
       NULL
    );
    sqliteFree(zWide);
  }else{
    h = CreateFileA(zFilename,
       GENERIC_READ | GENERIC_WRITE,
       0,
       NULL,
       CREATE_ALWAYS,
       fileflags,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;
  OpenCounter(+1);
  TRACE3("OPEN EX %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
int sqlite3OsOpenReadOnly(const char *zFilename, OsFile *id){
  HANDLE h;
  WCHAR *zWide = utf8ToUnicode(zFilename);
  assert( !id->isOpen );
  if( zWide ){
    h = CreateFileW(zWide,
       GENERIC_READ,
       0,
       NULL,
       OPEN_EXISTING,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
    sqliteFree(zWide);
  }else{
    h = CreateFileA(zFilename,
       GENERIC_READ,
       0,
       NULL,
       OPEN_EXISTING,
       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
       NULL
    );
  }
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  id->isOpen = 1;
  OpenCounter(+1);
  TRACE3("OPEN RO %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
**
** This routine is only meaningful for Unix.  It is a no-op under
** windows since windows does not support hard links.
**
** On success, a handle for a previously open file is at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id unchanged.
*/
int sqlite3OsOpenDirectory(
  const char *zDirname,
  OsFile *id
){
  return SQLITE_OK;
}

/*
** If the following global variable points to a string which is the
** name of a directory, then that directory will be used to store
** temporary files.
*/
char *sqlite3_temp_directory = 0;

/*
** Create a temporary file name in zBuf.  zBuf must be big enough to
** hold at least SQLITE_TEMPNAME_SIZE characters.
*/
int sqlite3OsTempFileName(char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  int i, j;
  char zTempPath[SQLITE_TEMPNAME_SIZE];
  if( sqlite3_temp_directory ){
    strncpy(zTempPath, sqlite3_temp_directory, SQLITE_TEMPNAME_SIZE-30);
    zTempPath[SQLITE_TEMPNAME_SIZE-30] = 0;
  }else if( isNT() ){
    char *zMulti;
    WCHAR zWidePath[SQLITE_TEMPNAME_SIZE];
    GetTempPathW(SQLITE_TEMPNAME_SIZE-30, zWidePath);
    zMulti = unicodeToUtf8(zWidePath);
    if( zMulti ){
      strncpy(zTempPath, zMulti, SQLITE_TEMPNAME_SIZE-30);
      zTempPath[SQLITE_TEMPNAME_SIZE-30] = 0;
      sqliteFree(zMulti);
    }
  }else{
    GetTempPathA(SQLITE_TEMPNAME_SIZE-30, zTempPath);
  }
  for(i=strlen(zTempPath); i>0 && zTempPath[i-1]=='\\'; i--){}
  zTempPath[i] = 0;
  for(;;){
    sprintf(zBuf, "%s\\"TEMP_FILE_PREFIX, zTempPath);
    j = strlen(zBuf);
    sqlite3Randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
    if( !sqlite3OsFileExists(zBuf) ) break;
  }
  TRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** Close a file.
*/
int sqlite3OsClose(OsFile *id){
  if( id->isOpen ){
    TRACE2("CLOSE %d\n", id->h);
    CloseHandle(id->h);
    OpenCounter(-1);
    id->isOpen = 0;
  }
  return SQLITE_OK;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
int sqlite3OsRead(OsFile *id, void *pBuf, int amt){
  DWORD got;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  TRACE3("READ %d lock=%d\n", id->h, id->locktype);
  if( !ReadFile(id->h, pBuf, amt, &got, 0) ){
    got = 0;
  }
  if( got==(DWORD)amt ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}

/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
int sqlite3OsWrite(OsFile *id, const void *pBuf, int amt){
  int rc = 0;
  DWORD wrote;
  assert( id->isOpen );
  SimulateIOError(SQLITE_IOERR);
  SimulateDiskfullError;
  TRACE3("WRITE %d lock=%d\n", id->h, id->locktype);
  assert( amt>0 );
  while( amt>0 && (rc = WriteFile(id->h, pBuf, amt, &wrote, 0))!=0 && wrote>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }
  if( !rc || amt>(int)wrote ){
    return SQLITE_FULL;
  }
  return SQLITE_OK;
}

/*
** Some microsoft compilers lack this definition.
*/
#ifndef INVALID_SET_FILE_POINTER