C++ Path::exists方法代码示例

// Insert a file into the archive before some other member. This also takes care
// of extracting the necessary flags and information from the file.
bool
Archive::addFileBefore(const sys::Path& filePath, iterator where, 
                        std::string* ErrMsg) {
  if (!filePath.exists()) {
    if (ErrMsg)
      *ErrMsg = "Can not add a non-existent file to archive";
    return true;
  }

  ArchiveMember* mbr = new ArchiveMember(this);

  mbr->data = 0;
  mbr->path = filePath;
  const sys::FileStatus *FSInfo = mbr->path.getFileStatus(false, ErrMsg);
  if (!FSInfo) {
    delete mbr;
    return true;
  }
  mbr->info = *FSInfo;

  unsigned flags = 0;
  bool hasSlash = filePath.str().find('/') != std::string::npos;
  if (hasSlash)
    flags |= ArchiveMember::HasPathFlag;
  if (hasSlash || filePath.str().length() > 15)
    flags |= ArchiveMember::HasLongFilenameFlag;
  std::string magic;
  mbr->path.getMagicNumber(magic,4);
  switch (sys::IdentifyFileType(magic.c_str(),4)) {
    case sys::Bitcode_FileType:
      flags |= ArchiveMember::BitcodeFlag;
      break;
    default:
      break;
  }
  mbr->flags = flags;
  members.insert(where,mbr);
  return false;
}

// This method allows an ArchiveMember to be replaced with the data for a
// different file, presumably as an update to the member. It also makes sure
// the flags are reset correctly.
bool ArchiveMember::replaceWith(const sys::Path& newFile, std::string* ErrMsg) {
  if (!newFile.exists()) {
    if (ErrMsg) 
      *ErrMsg = "Can not replace an archive member with a non-existent file";
    return true;
  }

  data = 0;
  path = newFile;

  // SVR4 symbol tables have an empty name
  if (path.str() == ARFILE_SVR4_SYMTAB_NAME)
    flags |= SVR4SymbolTableFlag;
  else
    flags &= ~SVR4SymbolTableFlag;

  // BSD4.4 symbol tables have a special name
  if (path.str() == ARFILE_BSD4_SYMTAB_NAME)
    flags |= BSD4SymbolTableFlag;
  else
    flags &= ~BSD4SymbolTableFlag;

  // LLVM symbol tables have a very specific name
  if (path.str() == ARFILE_LLVM_SYMTAB_NAME)
    flags |= LLVMSymbolTableFlag;
  else
    flags &= ~LLVMSymbolTableFlag;

  // String table name
  if (path.str() == ARFILE_STRTAB_NAME)
    flags |= StringTableFlag;
  else
    flags &= ~StringTableFlag;

  // If it has a slash then it has a path
  bool hasSlash = path.str().find('/') != std::string::npos;
  if (hasSlash)
    flags |= HasPathFlag;
  else
    flags &= ~HasPathFlag;

  // If it has a slash or its over 15 chars then its a long filename format
  if (hasSlash || path.str().length() > 15)
    flags |= HasLongFilenameFlag;
  else
    flags &= ~HasLongFilenameFlag;

  // Get the signature and status info
  const char* signature = (const char*) data;
  std::string magic;
  if (!signature) {
    path.getMagicNumber(magic,4);
    signature = magic.c_str();
    std::string err;
    const sys::FileStatus *FSinfo = path.getFileStatus(false, ErrMsg);
    if (FSinfo)
      info = *FSinfo;
    else
      return true;
  }

  // Determine what kind of file it is.
  switch (sys::IdentifyFileType(signature,4)) {
    case sys::Bitcode_FileType:
      flags |= BitcodeFlag;
      break;
    default:
      flags &= ~BitcodeFlag;
      break;
  }
  return false;
}