#endif

#ifndef LABEL_SECURITY_INFORMATION
#   define LABEL_SECURITY_INFORMATION (0x00000010L)
#endif

#if defined(__MSVCRT__)
static HANDLE dllhandle = NULL;
static DWORD WINAPI (*getFinalPathNameByHandleW) (HANDLE, LPWSTR, DWORD, DWORD) = NULL;
static BOOLEAN APIENTRY (*createSymbolicLinkW) (LPCWSTR, LPCWSTR, DWORD) = NULL;
#endif

/* a couple defines to make the borrowed struct below compile */
#ifndef _ANONYMOUS_UNION
# define _ANONYMOUS_UNION
#endif
#define DUMMYUNIONNAME

    struct {
      UCHAR DataBuffer[1];
    } GenericReparseBuffer;
  } DUMMYUNIONNAME;
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;

#define LINK_BUFFER_SIZE 1024

static int isVistaOrLater(){
    if( !dllhandle ){
        HANDLE h = LoadLibraryW(L"KERNEL32");
        createSymbolicLinkW = (BOOLEAN APIENTRY (*) (LPCWSTR, LPCWSTR, DWORD)) GetProcAddress(h, "CreateSymbolicLinkW");
        getFinalPathNameByHandleW = (DWORD WINAPI (*) (HANDLE, LPWSTR, DWORD, DWORD)) GetProcAddress(h, "GetFinalPathNameByHandleW");
        dllhandle = h;
    }
    return createSymbolicLinkW != NULL;
}

/*
** Fill stat buf with information received from GetFileAttributesExW().
** Does not follow symbolic links, returning instead information about
** the link itself.
** Returns 0 on success, 1 on failure.
*/
int win32_lstat(const wchar_t *zFilename, struct fossilStat *buf){
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesExW(zFilename, GetFileExInfoStandard, &attr);
  if( rc ){
    ssize_t tlen = 0; /* assume it is not a symbolic link */

    /* if it is a reparse point it *might* be a symbolic link */
    /* so defer to win32_readlink to actually check */
    if( attr.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT ){
      char *tname = fossil_filename_to_utf8(zFilename);
      char tlink[LINK_BUFFER_SIZE];
      tlen = win32_readlink(tname, tlink, sizeof(tlink));
      fossil_filename_free(tname);
    }

    ULARGE_INTEGER ull;

    /* if a link was retrieved, it is a symlink, otherwise a dir or file */
    if( tlen == 0 ){
      buf->st_mode = ((attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ?
                       S_IFDIR : S_IFREG);

      buf->st_size = (((i64)attr.nFileSizeHigh)<<32) | attr.nFileSizeLow;
    }else{
      buf->st_mode = S_IFLNK;
      buf->st_size = tlen;
    }

    ull.LowPart = attr.ftLastWriteTime.dwLowDateTime;
    ull.HighPart = attr.ftLastWriteTime.dwHighDateTime;
    buf->st_mtime = ull.QuadPart / 10000000ULL - 11644473600ULL;
  }
  return !rc;
}

/*
** Fill stat buf with information received from win32_lstat().
** If a symbolic link is found, follow it and return information about
** the target, repeating until an actual target is found.
** Limit the number of loop iterations so as to avoid an infinite loop
** due to circular links. This should never happen because
** GetFinalPathNameByHandleW() should always preclude that need, but being
** prepared to loop seems prudent, or at least not harmful.
** Returns 0 on success, 1 on failure.
*/
int win32_stat(const wchar_t *zFilename, struct fossilStat *buf){
  int rc;
  HANDLE file;
  wchar_t nextFilename[LINK_BUFFER_SIZE];
  DWORD len;
  int iterationsRemaining = 8; /* 8 is arbitrary, can be modified as needed */

  while (iterationsRemaining-- > 0){
    rc = win32_lstat(zFilename, buf);

    /* exit on error or not link */
    if( (rc != 0) || (buf->st_mode != S_IFLNK) )
      break;

    /* it is a link, so open the linked file */
    file = CreateFileW(zFilename, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
    if( (file == NULL) || (file == INVALID_HANDLE_VALUE) ){
      rc = 1;
      break;
    }

    /* get the final path name and close the handle */
    if( isVistaOrLater() ){
      len = getFinalPathNameByHandleW(file, nextFilename, LINK_BUFFER_SIZE - 1, 0);
    }else{
      len = -1;
    }
    CloseHandle(file);

    /* if any problems getting the final path name error so exit */
    if( (len <= 0) || (len > LINK_BUFFER_SIZE - 1) ){
      rc = 1;
      break;
    }

    /* prepare to try again just in case we have a chain to follow */
    /* this shouldn't happen, but just trying to be safe */
    zFilename = nextFilename;
  }

  return rc;
}

/*
** An implementation of a posix-like readlink function for win32.
** Copies the target of a symbolic link to buf if possible.
** Returns the length of the link copied to buf on success, -1 on failure.
*/
ssize_t win32_readlink(const char *path, char *buf, size_t bufsiz){
  /* assume we're going to fail */
  ssize_t rv = -1;

  /* does path reference a reparse point? */
  WIN32_FILE_ATTRIBUTE_DATA attr;
  int rc = GetFileAttributesEx(path, GetFileExInfoStandard, &attr);
  if( rc && (attr.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) ){

    /* since it is a reparse point, open it */
    HANDLE file = CreateFile(path, FILE_READ_EA, 0, NULL, OPEN_EXISTING,
      FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);
    if( (file != NULL) && (file != INVALID_HANDLE_VALUE) ){

      /* use DeviceIoControl to get the reparse point data */

      int data_size = sizeof(REPARSE_DATA_BUFFER) + LINK_BUFFER_SIZE * sizeof(wchar_t);
      REPARSE_DATA_BUFFER* data = fossil_malloc(data_size);
      DWORD data_used;

      data->ReparseTag = IO_REPARSE_TAG_SYMLINK;
      data->ReparseDataLength = 0;
      data->Reserved = 0;

      int rc = DeviceIoControl(file, FSCTL_GET_REPARSE_POINT, NULL, 0,
        data, data_size, &data_used, NULL);

      /* did the reparse point data fit into the desired buffer? */
      if( rc && (data_used < data_size) ){
        /* it fit, so setup the print name for further processing */
        USHORT
          offset = data->SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(wchar_t),
          length = data->SymbolicLinkReparseBuffer.PrintNameLength / sizeof(wchar_t);
        char *temp;
        data->SymbolicLinkReparseBuffer.PathBuffer[offset + length] = 0;

        /* convert the filename to utf8, copy it, and discard the converted copy */
        temp = fossil_filename_to_utf8(data->SymbolicLinkReparseBuffer.PathBuffer + offset);
        rv = strlen(temp);
        if( rv >= bufsiz )
          rv = bufsiz;
        memcpy(buf, temp, rv);
        fossil_filename_free(temp);
      }

      fossil_free(data);

      /* all done, close the reparse point */
      CloseHandle(file);
    }
  }

  return rv;
}

/*
** Either unlink a file or remove a directory on win32 systems.
** To delete a symlink on a posix system, you simply unlink the entry.
** Unfortunately for our purposes, win32 differentiates between symlinks for
** files and for directories. Thus you must unlink a file symlink or rmdir a
** directory symlink. This is a convenience function used when we know we're
** deleting a symlink of some type.
** Returns 0 on success, 1 on failure.
*/
int win32_unlink_rmdir(const wchar_t *zFilename){
  int rc = 0;
  WIN32_FILE_ATTRIBUTE_DATA attr;
  if( GetFileAttributesExW(zFilename, GetFileExInfoStandard, &attr) ){
    if( (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY )
      rc = RemoveDirectoryW(zFilename);
    else
      rc = DeleteFileW(zFilename);
  }
  return !rc;
}

*/
int win32_symlink(const char *oldpath, const char *newpath){
  fossilStat stat;
  int created = 0;
  DWORD flags = 0;
  wchar_t *zMbcs, *zMbcsOld;

  /* does oldpath exist? is it a dir or a file? */
  zMbcsOld = fossil_utf8_to_filename(oldpath);
  if( win32_stat(zMbcsOld, &stat) == 0 ){
    if( stat.st_mode == S_IFDIR ){
      flags = SYMBOLIC_LINK_FLAG_DIRECTORY;
    }
  }

  /* remove newpath before creating the symlink */
  zMbcs = fossil_utf8_to_filename(newpath);
  win32_unlink_rmdir(zMbcs);
  if( isVistaOrLater() ){
    created = createSymbolicLinkW(zMbcs, zMbcsOld, flags);
  }
  fossil_filename_free(zMbcs);
  fossil_filename_free(zMbcsOld);

  /* if the symlink was not created, create a plain text file */
  if( !created ){
    Blob content;
    blob_set(&content, oldpath);
    blob_write_to_file(&content, newpath);
    blob_reset(&content);
    created = 1;
  }

  return !created;
}

/*
** Given a pathname to a file, return true if:
**   1. the file exists
**   2. the file is a symbolic link
**   3. the symbolic link's attributes can be acquired
**   4. the symbolic link type is different than the target type
*/
int win32_check_symlink_type_changed(const char* zName){
  int changed = 0;
  wchar_t* zMbcs;
  fossilStat lstat_buf, stat_buf;
  WIN32_FILE_ATTRIBUTE_DATA lstat_attr;
  zMbcs = fossil_utf8_to_filename(zName);
  if( win32_stat(zMbcs, &stat_buf) != 0 ){
    stat_buf.st_mode = S_IFREG;
  }
  changed =
    (win32_lstat(zMbcs, &lstat_buf) == 0) &&
    (lstat_buf.st_mode == S_IFLNK) &&
    GetFileAttributesExW(zMbcs, GetFileExInfoStandard, &lstat_attr) &&
    ((stat_buf.st_mode == S_IFDIR) != ((lstat_attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY));
  fossil_filename_free(zMbcs);
  return changed;

  wchar_t *pFilename;
  wchar_t fullName[MAX_PATH+1];
  DWORD fullLength;
  wchar_t volName[MAX_PATH+1];
  DWORD fsFlags;

  /* symlinks only supported on vista or greater */
  if( !isVistaOrLater() ){
    return 0;
  }

  /* next we need to check to see if the privilege is available */

  /* can't check privilege if we can't lookup its value */
  if( !LookupPrivilegeValue(NULL, SE_CREATE_SYMBOLIC_LINK_NAME, &luid) ){
    return 0;
  }

  /* can't check privilege if we can't open the process token */
  process = GetCurrentProcess();
  if( !OpenProcessToken(process, TOKEN_ADJUST_PRIVILEGES|TOKEN_QUERY, &token) ){
    return 0;
  }

  /* by this point, we have a process token and the privilege value */
  /* try to enable the privilege then close the token */

  tp.PrivilegeCount = 1;
  tp.Privileges[0].Luid = luid;
  tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;

  AdjustTokenPrivileges(token, FALSE, &tp, sizeof(TOKEN_PRIVILEGES), NULL, NULL);
  status = GetLastError();

  CloseHandle(token);

  /* any error means we failed to enable the privilege, symlinks not supported */
  if( status != ERROR_SUCCESS ){
    return 0;
  }

  /* assume no support for symlinks */
  success = 0;

  pFilename = fossil_utf8_to_filename(zFilename);

  /* given the filename we're interested in, symlinks are supported if */
  /* 1. we can get the full name of the path from the given path */
  fullLength = GetFullPathNameW(pFilename, sizeof(fullName), fullName, NULL);
  if( (fullLength > 0) && (fullLength < sizeof(fullName)) ){
    /* 2. we can get the volume path name from the full name */
    if( GetVolumePathNameW(fullName, volName, sizeof(volName)) ){
      /* 3. we can get volume information from the volume path name */
      if( GetVolumeInformationW(volName, NULL, 0, NULL, NULL, &fsFlags, NULL, 0) ){
        /* 4. the given volume support reparse points */
        if( fsFlags & FILE_SUPPORTS_REPARSE_POINTS ){
          /* all four conditions were true, so we support symlinks; success! */
          success = 1;
        }
      }
    }
  }

  fossil_filename_free(pFilename);

  return success;
}

/*
** Wrapper around the access() system call.  This code was copied from Tcl
** 8.6 and then modified.
*/
int win32_access(const wchar_t *zFilename, int flags){

                   &privSetSize, &grantedAccess, &accessYesNo) ){
    /*
     * Unable to perform access check.
     */

    rc = -1; goto done;
  }
  if( !accessYesNo ){
    rc = -1;
  }

done:

  if( hToken != NULL ){
    CloseHandle(hToken);
  }
  if( impersonated ){