Support Windows share paths in the Path class.

sdk/lib/io/path.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * A Path, which is a String interpreted as a sequence of path segments,
  * which are strings, separated by forward slashes.
  * Paths are immutable wrappers of a String, that offer member functions for
  * useful path manipulations and queries.  Joining of paths and normalization
  * interpret '.' and '..' in the usual way.
  */
 abstract class Path {
   /**
    * Creates a Path from the String [source].  [source] is used as-is, so if
    * the string does not consist of segments separated by forward slashes, the
    * behavior may not be as expected.  Paths are immutable.
    */
   factory Path(String source) => new _Path(source);
 
   /**
    * Creates a Path from a String that uses the native filesystem's conventions.
-   * On Windows, this converts '\' to '/', and adds a '/' before a drive letter.
+   *
+   * On Windows, this converts '\' to '/' and has special handling for drive
+   * letters and shares.
+   *
+   * If the path contains a drive letter a '/' is added before the drive letter.
+   *
+   *     new Path.fromNative(r'c:\a\b').toString() == '/c:/a/b'
+   *
    * A path starting with '/c:/' (or any other character instead of 'c') is
    * treated specially.  Backwards links ('..') cannot cancel the drive letter.
+   *
+   * If the path is a share path this is recorded in the Path object and
+   * maintained in operations on the Path object.
+   *
+   *     var share = new Path.fromNative(r'\\share\a\b\c');
+   *     share.isWindowsShare == true
+   *     share.toString() == '/share/a/b/c'
+   *     share.toNativePath() == r'\\share\a\b\c'
+   *     share.append('final').isWindowsShare == true
    */
   factory Path.fromNative(String source) => new _Path.fromNative(source);
 
   /**
    * Is this path the empty string?
    */
   bool get isEmpty;
 
   /**
    * Is this path an absolute path, beginning with a path separator?
    */
   bool get isAbsolute;
 
   /**
+   * Is this path a Windows share path?
+   */
+  bool get isWindowsShare;
+
+  /**
    * Does this path end with a path separator?
    */
   bool get hasTrailingSeparator;
 
   /**
    * Does this path contain no consecutive path separators, no segments that
    * are '.' unless the path is exactly '.', and segments that are '..' only
    * as the leading segments on a relative path?
    */
   bool get isCanonical;
@@ skipping 116 matching lines @@
 
   /**
    * The part of [filename] after the last '.', or '' if [filename]
    * contains no '.'.  If [filename] is '.' or '..', returns ''.
    *
    *     new Path('tiger.svg').extension == 'svg'
    *     new Path('/src/dart/dart_secrets').extension == ''
    */
   String get extension;
 }