add cache list command to pub

utils/pub/hosted_source.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 hosted_source;
 
 import 'dart:async';
 import 'dart:io' as io;
 import 'dart:json' as json;
 import 'dart:uri';
@@ skipping 75 matching lines @@
       }).then((_) => true);
     });
   }
 
   /// The system cache directory for the hosted source contains subdirectories
   /// for each separate repository URL that's used on the system. Each of these
   /// subdirectories then contains a subdirectory for each package installed
   /// from that site.
   Future<String> systemCacheDirectory(PackageId id) {
     var parsed = _parseDescription(id.description);
-    var url = parsed.last.replaceAll(new RegExp(r"^https?://"), "");
+    var url = _getSourceDirectory(parsed.last);
     var urlDir = replace(url, new RegExp(r'[<>:"\\/|?*%]'), (match) {
       return '%${match[0].codeUnitAt(0)}';
     });
 
     return new Future.immediate(
         path.join(systemCacheRoot, urlDir, "${parsed.first}-${id.version}"));
   }
 
   String packageName(description) => _parseDescription(description).first;
 
   bool descriptionsEqual(description1, description2) =>
       _parseDescription(description1) == _parseDescription(description2);
 
   /// Ensures that [description] is a valid hosted package description.
   ///
   /// There are two valid formats. A plain string refers to a package with the
   /// given name from the default host, while a map with keys "name" and "url"
   /// refers to a package with the given name from the host at the given URL.
   dynamic parseDescription(String containingPath, description,
                            {bool fromLockFile: false}) {
     _parseDescription(description);
     return description;
   }
 
+  Future<List<Package>> getCachedPackages() {
+    return defer(() {
+      var cacheDir = path.join(systemCacheRoot, 
+                               _getSourceDirectory(_defaultUrl)); 
+      if (!dirExists(cacheDir)) return [];
+    
+      return listDir(path.join(cacheDir)).then((entries) {
+        return entries.map((entry) => 
+          new Package.load(null, entry, systemCache.sources));
+      });  
+    });
+  }
+  
   /// When an error occurs trying to read something about [package] from [url],
   /// this tries to translate into a more user friendly error message. Always
   /// throws an error, either the original one or a better one.
   void _throwFriendlyError(AsyncError asyncError, package, url) {
     if (asyncError.error is PubHttpException &&
         asyncError.error.response.statusCode == 404) {
       throw 'Could not find package "$package" at $url.';
     }
 
     if (asyncError.error is TimeoutException) {
       throw 'Timed out trying to find package "$package" at $url.';
     }
 
     if (asyncError.error is io.SocketIOException) {
       throw 'Got socket error trying to find package "$package" at $url.\n'
           '${asyncError.error.osError}';
     }
 
     // Otherwise re-throw the original exception.
     throw asyncError;
   }
 
 }
 
 /// The URL of the default package repository.
 final _defaultUrl = "https://pub.dartlang.org";
 
+String _getSourceDirectory(String url) {
+  return url.replaceAll(new RegExp(r"^https?://"), "");
+}
+
 /// Parses [description] into its server and package name components, then
 /// converts that to a Uri given [pattern]. Ensures the package name is
 /// properly URL encoded.
 Uri _makeUrl(description, String pattern(String server, String package)) {
   var parsed = _parseDescription(description);
   var server = parsed.last;
   var package = encodeUriComponent(parsed.first);
   return new Uri(pattern(server, package));
 }
 
@@ skipping 29 matching lines @@
   }
 
   var name = description["name"];
   if (name is! String) {
     throw new FormatException("The 'name' key must have a string value.");
   }
 
   var url = description.containsKey("url") ? description["url"] : _defaultUrl;
   return new Pair<String, String>(name, url);
 }