Function find_first_component

ext/src/llvm/Path.cpp:59–91

  }

  StringRef find_first_component(StringRef path, Style style) {
    // Look for this first component in the following order.
    // * empty (in this case we return an empty string)
    // * either C: or {//,\\}net.
    // * {/,\}
    // * {file,directory}name

    if (path.empty())
      return path;

    if (real_style(style) == Style::windows) {
      // C:
      if (path.size() >= 2 &&
          std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
        return path.substr(0, 2);
    }

    // //net
    if ((path.size() > 2) && is_separator(path[0], style) &&
        path[0] == path[1] && !is_separator(path[2], style)) {
      // Find the next directory separator.
      size_t end = path.find_first_of(separators(style), 2);
      return path.substr(0, end);
    }

    // {/,\}
    if (is_separator(path[0], style))
      return path.substr(0, 1);

    // * {file,directory}name
    size_t end = path.find_first_of(separators(style));
    return path.substr(0, end);
  }

  // Returns the first character of the filename in str. For paths ending in
  // '/', it returns the position of the '/'.