src/lib/path.js

// import {cwd} from './env.js'
let cwd;
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

//'use strict';

const
  CHAR_UPPERCASE_A = 65,
  CHAR_LOWERCASE_A = 97,
  CHAR_UPPERCASE_Z = 90,
  CHAR_LOWERCASE_Z = 122,
  CHAR_DOT = 46,
  CHAR_FORWARD_SLASH = 47,
  CHAR_BACKWARD_SLASH = 92,
  CHAR_COLON = 58,
  CHAR_QUESTION_MARK = 63;

function isPathSeparator(code) {
	return code === CHAR_FORWARD_SLASH || code === CHAR_BACKWARD_SLASH;
}

function isPosixPathSeparator(code) {
	return code === CHAR_FORWARD_SLASH;
}

// Resolves . and .. elements in a path with directory names
function normalizeString(path, allowAboveRoot, separator, isPathSeparator) {
  let res = '';
  let lastSegmentLength = 0;
  let lastSlash = -1;
  let dots = 0;
  let code = 0;
  for (let i = 0; i <= path.length; ++i) {
	if (i < path.length)
	  code = path.charCodeAt(i);
	else if (isPathSeparator(code))
	  break;
	else
	  code = CHAR_FORWARD_SLASH;

	if (isPathSeparator(code)) {
	  if (lastSlash === i - 1 || dots === 1) {
		// NOOP
	  } else if (dots === 2) {
		if (res.length < 2 || lastSegmentLength !== 2 ||
			res.charCodeAt( res.length - 1) !== CHAR_DOT ||
			res.charCodeAt(res.length - 2) !== CHAR_DOT) {
		  if (res.length > 2) {
			const lastSlashIndex = res.lastIndexOf(separator);
			if (lastSlashIndex === -1) {
			  res = '';
			  lastSegmentLength = 0;
			} else {
			  res = res.slice(0, lastSlashIndex);
			  lastSegmentLength =
				res.length - 1 - res.lastIndexOf(res, separator);
			}
			lastSlash = i;
			dots = 0;
			continue;
		  } else if (res.length !== 0) {
			res = '';
			lastSegmentLength = 0;
			lastSlash = i;
			dots = 0;
			continue;
		  }
		}
		if (allowAboveRoot) {
		  res += res.length > 0 ? `${separator}..` : '..';
		  lastSegmentLength = 2;
		}
	  } else {
		if (res.length > 0)
		  res += `${separator}${path.slice(lastSlash + 1, i)}`;
		else
		  res = path.slice(lastSlash + 1, i);
		lastSegmentLength = i - lastSlash - 1;
	  }
	  lastSlash = i;
	  dots = 0;
	} else if (code === CHAR_DOT && dots !== -1) {
	  ++dots;
	} else {
	  dots = -1;
	}
  }
  return res;
}

const path = {
    // path.resolve([from ...], to)
    resolve(...args) {
      let resolvedPath = '';
      let resolvedAbsolute = false;
  
      for (let i = args.length - 1; i >= -1 && !resolvedAbsolute; i--) {
        // orig const path = i >= 0 ? args[i] : posixCwd();
        const path = i >= 0 ? args[i] : (cwd !== undefined ? cwd : '/');
        // const path = i >= 0 ? args[i] : '/';
  
        // Skip empty entries
        if (path.length === 0) {
          continue;
        }
  
        resolvedPath = `${path}/${resolvedPath}`;
        resolvedAbsolute =
          path.charCodeAt(0) === CHAR_FORWARD_SLASH;
      }
  
      // At this point the path should be resolved to a full absolute path, but
      // handle relative paths to be safe (might happen when process.cwd() fails)
  
      // Normalize the path
      resolvedPath = normalizeString(resolvedPath, !resolvedAbsolute, '/',
                                     isPosixPathSeparator);
  
      if (resolvedAbsolute) {
        return `/${resolvedPath}`;
      }
      return resolvedPath.length > 0 ? resolvedPath : '.';
    },
  
    normalize(path) {
      if (path.length === 0)
        return '.';
  
      const isAbsolute =
        path.charCodeAt(0) === CHAR_FORWARD_SLASH;
      const trailingSeparator =
        path.charCodeAt(path.length - 1) === CHAR_FORWARD_SLASH;
  
      // Normalize the path
      path = normalizeString(path, !isAbsolute, '/', isPosixPathSeparator);
  
      if (path.length === 0) {
        if (isAbsolute)
          return '/';
        return trailingSeparator ? './' : '.';
      }
      if (trailingSeparator)
        path += '/';
  
      return isAbsolute ? `/${path}` : path;
    },
  
    isAbsolute(path) {
      return path.length > 0 &&
             path.charCodeAt(0) === CHAR_FORWARD_SLASH;
    },
  
    join(...args) {
      if (args.length === 0)
        return '.';
      let joined;
      for (let i = 0; i < args.length; ++i) {
        const arg = args[i];
        if (arg.length > 0) {
          if (joined === undefined)
            joined = arg;
          else
            joined += `/${arg}`;
        }
      }
      if (joined === undefined)
        return '.';
      return path.normalize(joined);
    },
  
    relative(from, to) {
      if (from === to)
        return '';
  
      // Trim leading forward slashes.
      from = path.resolve(from);
      to = path.resolve(to);
  
      if (from === to)
        return '';
  
      const fromStart = 1;
      const fromEnd = from.length;
      const fromLen = fromEnd - fromStart;
      const toStart = 1;
      const toLen = to.length - toStart;
  
      // Compare paths to find the longest common path from root
      const length = (fromLen < toLen ? fromLen : toLen);
      let lastCommonSep = -1;
      let i = 0;
      for (; i < length; i++) {
        const fromCode = from.charCodeAt(fromStart + i);
        if (fromCode !== to.charCodeAt(toStart + i))
          break;
        else if (fromCode === CHAR_FORWARD_SLASH)
          lastCommonSep = i;
      }
      if (i === length) {
        if (toLen > length) {
          if (to.charCodeAt(toStart + i) === CHAR_FORWARD_SLASH) {
            // We get here if `from` is the exact base path for `to`.
            // For example: from='/foo/bar'; to='/foo/bar/baz'
            return to.slice(toStart + i + 1);
          }
          if (i === 0) {
            // We get here if `from` is the root
            // For example: from='/'; to='/foo'
            return to.slice(toStart + i);
          }
        } else if (fromLen > length) {
          if (from.charCodeAt(fromStart + i) ===
              CHAR_FORWARD_SLASH) {
            // We get here if `to` is the exact base path for `from`.
            // For example: from='/foo/bar/baz'; to='/foo/bar'
            lastCommonSep = i;
          } else if (i === 0) {
            // We get here if `to` is the root.
            // For example: from='/foo/bar'; to='/'
            lastCommonSep = 0;
          }
        }
      }
  
      let out = '';
      // Generate the relative path based on the path difference between `to`
      // and `from`.
      for (i = fromStart + lastCommonSep + 1; i <= fromEnd; ++i) {
        if (i === fromEnd ||
            from.charCodeAt(i) === CHAR_FORWARD_SLASH) {
          out += out.length === 0 ? '..' : '/..';
        }
      }
  
      // Lastly, append the rest of the destination (`to`) path that comes after
      // the common path parts.
      return `${out}${to.slice(toStart + lastCommonSep)}`;
    },
  
    toNamespacedPath(path) {
      // Non-op on posix systems
      return path;
    },
  
    dirname(path) {
      if (path.length === 0)
        return '.';
      const hasRoot = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
      let end = -1;
      let matchedSlash = true;
      for (let i = path.length - 1; i >= 1; --i) {
        if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
          if (!matchedSlash) {
            end = i;
            break;
          }
        } else {
          // We saw the first non-path separator
          matchedSlash = false;
        }
      }
  
      if (end === -1)
        return hasRoot ? '/' : '.';
      if (hasRoot && end === 1)
        return '//';
      return path.slice(0, end);
    },
  
    basename(path, ext) {
      let start = 0;
      let end = -1;
      let matchedSlash = true;
  
      if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
        if (ext === path)
          return '';
        let extIdx = ext.length - 1;
        let firstNonSlashEnd = -1;
        for (let i = path.length - 1; i >= 0; --i) {
          const code = path.charCodeAt(i);
          if (code === CHAR_FORWARD_SLASH) {
            // If we reached a path separator that was not part of a set of path
            // separators at the end of the string, stop now
            if (!matchedSlash) {
              start = i + 1;
              break;
            }
          } else {
            if (firstNonSlashEnd === -1) {
              // We saw the first non-path separator, remember this index in case
              // we need it if the extension ends up not matching
              matchedSlash = false;
              firstNonSlashEnd = i + 1;
            }
            if (extIdx >= 0) {
              // Try to match the explicit extension
              if (code === ext.charCodeAt(extIdx)) {
                if (--extIdx === -1) {
                  // We matched the extension, so mark this as the end of our path
                  // component
                  end = i;
                }
              } else {
                // Extension does not match, so our result is the entire path
                // component
                extIdx = -1;
                end = firstNonSlashEnd;
              }
            }
          }
        }
  
        if (start === end)
          end = firstNonSlashEnd;
        else if (end === -1)
          end = path.length;
        return path.slice(start, end);
      }
      for (let i = path.length - 1; i >= 0; --i) {
        if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
          // If we reached a path separator that was not part of a set of path
          // separators at the end of the string, stop now
          if (!matchedSlash) {
            start = i + 1;
            break;
          }
        } else if (end === -1) {
          // We saw the first non-path separator, mark this as the end of our
          // path component
          matchedSlash = false;
          end = i + 1;
        }
      }
  
      if (end === -1)
        return '';
      return path.slice(start, end);
    },
  
    extname(path) {
      let startDot = -1;
      let startPart = 0;
      let end = -1;
      let matchedSlash = true;
      // Track the state of characters (if any) we see before our first dot and
      // after any path separator we find
      let preDotState = 0;
      for (let i = path.length - 1; i >= 0; --i) {
        const code = path.charCodeAt(i);
        if (code === CHAR_FORWARD_SLASH) {
          // If we reached a path separator that was not part of a set of path
          // separators at the end of the string, stop now
          if (!matchedSlash) {
            startPart = i + 1;
            break;
          }
          continue;
        }
        if (end === -1) {
          // We saw the first non-path separator, mark this as the end of our
          // extension
          matchedSlash = false;
          end = i + 1;
        }
        if (code === CHAR_DOT) {
          // If this is our first dot, mark it as the start of our extension
          if (startDot === -1)
            startDot = i;
          else if (preDotState !== 1)
            preDotState = 1;
        } else if (startDot !== -1) {
          // We saw a non-dot and non-path separator before our dot, so we should
          // have a good chance at having a non-empty extension
          preDotState = -1;
        }
      }
  
      if (startDot === -1 ||
          end === -1 ||
          // We saw a non-dot character immediately before the dot
          preDotState === 0 ||
          // The (right-most) trimmed path component is exactly '..'
          (preDotState === 1 &&
           startDot === end - 1 &&
           startDot === startPart + 1)) {
        return '';
      }
      return path.slice(startDot, end);
    },
  
    format: _format.bind( null, '/'),
  
    parse(path) {
      const ret = { root: '', dir: '', base: '', ext: '', name: '' };
      if (path.length === 0)
        return ret;
      const isAbsolute =
        path.charCodeAt(0) === CHAR_FORWARD_SLASH;
      let start;
      if (isAbsolute) {
        ret.root = '/';
        start = 1;
      } else {
        start = 0;
      }
      let startDot = -1;
      let startPart = 0;
      let end = -1;
      let matchedSlash = true;
      let i = path.length - 1;
  
      // Track the state of characters (if any) we see before our first dot and
      // after any path separator we find
      let preDotState = 0;
  
      // Get non-dir info
      for (; i >= start; --i) {
        const code = path.charCodeAt(i);
        if (code === CHAR_FORWARD_SLASH) {
          // If we reached a path separator that was not part of a set of path
          // separators at the end of the string, stop now
          if (!matchedSlash) {
            startPart = i + 1;
            break;
          }
          continue;
        }
        if (end === -1) {
          // We saw the first non-path separator, mark this as the end of our
          // extension
          matchedSlash = false;
          end = i + 1;
        }
        if (code === CHAR_DOT) {
          // If this is our first dot, mark it as the start of our extension
          if (startDot === -1)
            startDot = i;
          else if (preDotState !== 1)
            preDotState = 1;
        } else if (startDot !== -1) {
          // We saw a non-dot and non-path separator before our dot, so we should
          // have a good chance at having a non-empty extension
          preDotState = -1;
        }
      }
  
      if (end !== -1) {
        const start = startPart === 0 && isAbsolute ? 1 : startPart;
        if (startDot === -1 ||
            // We saw a non-dot character immediately before the dot
            preDotState === 0 ||
            // The (right-most) trimmed path component is exactly '..'
            (preDotState === 1 &&
            startDot === end - 1 &&
            startDot === startPart + 1)) {
          ret.base = ret.name = path.slice(start, end);
        } else {
          ret.name = path.slice(start, startDot);
          ret.base = path.slice(start, end);
          ret.ext = path.slice(startDot, end);
        }
      }
  
      if (startPart > 0)
        ret.dir = path.slice(0, startPart - 1);
      else if (isAbsolute)
        ret.dir = '/';
  
      return ret;
    },
  
    sep: '/',
    delimiter: ':',
    win32: null,
    posix: null
  };

  function _format(sep, pathObject) {
    validateObject(pathObject, 'pathObject');
    const dir = pathObject.dir || pathObject.root;
    const base = pathObject.base ||
      `${pathObject.name || ''}${pathObject.ext || ''}`;
    if (!dir) {
      return base;
    }
    return dir === pathObject.root ? `${dir}${base}` : `${dir}${sep}${base}`;
  }
  
export default path