New, more validating, parser for URI.

runtime/bin/builtin.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.
 
 library builtin;
 import 'dart:io';
 import 'dart:async';
 import 'dart:convert';
 // import 'root_library'; happens here from C Code
 
@@ skipping 197 matching lines @@
     return '/${cwd[0]}:';
   }
   return null;
 }
 
 
 void _setWorkingDirectory(cwd) {
   _workingWindowsDrivePrefix = _extractDriveLetterPrefix(cwd);
   cwd = _sanitizeWindowsPath(cwd);
   cwd = _enforceTrailingSlash(cwd);
-  _workingDirectoryUri = new Uri(scheme: 'file', path: cwd);
+  _workingDirectoryUri = new Uri.file(cwd);
+  if (!_workingDirectoryUri.path.endsWith("/")) {
+    var directoryPath = _workingDirectoryUri.path + "/";
+    _workingDirectoryUri = _workingDirectoryUri.resolve(directoryPath);
+  }
+
   _logResolution('# Working Directory: $cwd');
 }
 
 
 _setPackageRoot(String packageRoot) {
   packageRoot = _enforceTrailingSlash(packageRoot);
   if (packageRoot.startsWith('file:') ||
       packageRoot.startsWith('http:') ||
       packageRoot.startsWith('https:')) {
     _packageRoot = _workingDirectoryUri.resolve(packageRoot);
   } else {
     _packageRoot = _workingDirectoryUri.resolveUri(new Uri.file(packageRoot));
   }
   _logResolution('# Package root: $packageRoot -> $_packageRoot');
 }
 
 
 String _resolveScriptUri(String scriptName) {
   if (_workingDirectoryUri == null) {
     throw 'No current working directory set.';
   }
   scriptName = _sanitizeWindowsPath(scriptName);
-
-  var scriptUri = Uri.parse(scriptName);
+  var scriptUri;
+  if (scriptName.startsWith("file:") ||
+      scriptName.startsWith("http:") ||
+      scriptName.startsWith("https:")) {
+    scriptUri = Uri.parse(scriptName);
+  } else {
+    // Assume it's a file name.
+    scriptUri = new Uri.file(scriptName);
+  }
   if (scriptUri.scheme != '') {
     // Script has a scheme, assume that it is fully formed.
     _entryPointScript = scriptUri;
   } else {
     // Script does not have a scheme, assume that it is a path,
     // resolve it against the working directory.
     _entryPointScript = _workingDirectoryUri.resolve(scriptName);
   }
   _logResolution('# Resolved entry point to: $_entryPointScript');
   return _entryPointScript.toString();
@@ skipping 189 matching lines @@
   } else if (Platform.isWindows) {
     filename = '$name.dll';
   } else {
     _logResolution(
         'Native extensions not supported on ${Platform.operatingSystem}');
     throw 'Native extensions not supported on ${Platform.operatingSystem}';
   }
 
   return [path, filename, name];
 }