Function getEncodedRootLength

src/utils/path.ts:73–131

(path: string)

};

const getEncodedRootLength = (path: string): number => {
  if (!path) return 0;
  const ch0 = path.charCodeAt(0);

  // POSIX or UNC
  if (ch0 === CharacterCodes.slash || ch0 === CharacterCodes.backslash) {
    if (path.charCodeAt(1) !== ch0) return 1; // POSIX: "/" (or non-normalized "\")

    const p1 = path.indexOf(ch0 === CharacterCodes.slash ? '/' : altDirectorySeparator, 2);
    if (p1 < 0) return path.length; // UNC: "//server" or "\\server"

    return p1 + 1; // UNC: "//server/" or "\\server\"
  }

  // DOS
  if (isVolumeCharacter(ch0) && path.charCodeAt(1) === CharacterCodes.colon) {
    const ch2 = path.charCodeAt(2);
    if (ch2 === CharacterCodes.slash || ch2 === CharacterCodes.backslash) return 3; // DOS: "c:/" or "c:\"
    if (path.length === 2) return 2; // DOS: "c:" (but not "c:d")
  }

  // URL
  const schemeEnd = path.indexOf(urlSchemeSeparator);
  if (schemeEnd !== -1) {
    const authorityStart = schemeEnd + urlSchemeSeparator.length;
    const authorityEnd = path.indexOf('/', authorityStart);
    if (authorityEnd !== -1) {
      // URL: "file:///", "file://server/", "file://server/path"
      // For local "file" URLs, include the leading DOS volume (if present).
      // Per https://www.ietf.org/rfc/rfc1738.txt, a host of "" or "localhost" is a
      // special case interpreted as "the machine from which the URL is being interpreted".
      const scheme = path.slice(0, schemeEnd);
      const authority = path.slice(authorityStart, authorityEnd);
      if (
        scheme === 'file' &&
        (authority === '' || authority === 'localhost') &&
        isVolumeCharacter(path.charCodeAt(authorityEnd + 1))
      ) {
        const volumeSeparatorEnd = getFileUrlVolumeSeparatorEnd(path, authorityEnd + 2);
        if (volumeSeparatorEnd !== -1) {
          if (path.charCodeAt(volumeSeparatorEnd) === CharacterCodes.slash) {
            // URL: "file:///c:/", "file://localhost/c:/", "file:///c%3a/", "file://localhost/c%3a/"
            return ~(volumeSeparatorEnd + 1);
          }
          if (volumeSeparatorEnd === path.length) {
            // URL: "file:///c:", "file://localhost/c:", "file:///c$3a", "file://localhost/c%3a"
            // but not "file:///c:d" or "file:///c%3ad"
            return ~volumeSeparatorEnd;
          }
        }
      }
      return ~(authorityEnd + 1); // URL: "file://server/", "http://server/"
    }
    return ~path.length; // URL: "file://server", "http://server"
  }

  // relative
  return 0;