Add support for pub install.

utils/pub/pub.dart

Index: utils/pub/pub.dart
diff --git a/utils/pub/pub.dart b/utils/pub/pub.dart
index eef7ba38e92ab37c359d7c54f6da3de8e0724cb1..377c3e6a4fe652a90661d513e1cb81d51b94b818 100644
--- a/utils/pub/pub.dart
+++ b/utils/pub/pub.dart
@@ -12,11 +12,15 @@
 #import('io.dart');
 #import('utils.dart');
 
-#source('cache.dart');
+#source('system_cache.dart');
+#source('app_cache.dart');
 #source('command_list.dart');
+#source('command_install.dart');
 #source('command_update.dart');
 #source('command_version.dart');
 #source('package.dart');
+#source('source.dart');
+#source('sdk_source.dart');
 
 main() {
   final args = new Options().arguments;
@@ -26,6 +30,7 @@ main() {
   // be consistent with other Unix apps.
   final commands = {
     'list': new ListCommand(),
+    'install': new InstallCommand(),
     'update': new UpdateCommand(),
     'version': new VersionCommand()
   };
@@ -52,17 +57,23 @@ main() {
   // TODO(rnystrom): Hack. This is temporary code to allow the pub tests to
   // pass in relevant paths. Eventually these should be either environment
   // variables or at least a cleaner arg parser.
-  var cacheDir;
+  var cacheDir, sdkDir;
   for (var i = 0; i < args.length; i++) {
     if (args[i].startsWith('--cachedir=')) {
       cacheDir = args[i].substring('--cachedir='.length);
       args.removeRange(i, 1);
-      break;
+      i--;
+    } else if (args[i].startsWith('--sdkdir=')) {
+      sdkDir = args[i].substring('--sdkdir='.length);
+      args.removeRange(i, 1);
+      i--;
     }
   }
 
   // TODO(rnystrom): Do we want this to be global?
-  final cache = new PackageCache(cacheDir);
+  final systemCache = new SystemCache(cacheDir);
+
+  Source.defaultSource = new SdkSource(sdkDir);
 
   // Select the command.
   final command = commands[args[0]];
@@ -74,7 +85,7 @@ main() {
   }
 
   args.removeRange(0, 1);
-  command.run(cache, args);
+  command.run(systemCache, args);
 }
 
 /** Displays usage information for the app. */
@@ -123,12 +134,14 @@ Future<Package> getWorkingPackage() {
 }
 
 class PubCommand {
-  PackageCache cache;
+  SystemCache systemCache;
+  AppCache appCache;
 
   abstract String get description();
 
-  void run(PackageCache cache_, List<String> args) {
-    cache = cache_;
+  void run(SystemCache systemCache_, List<String> args) {
+    systemCache = systemCache_;
+    appCache = new AppCache(workingDir, systemCache);
 
     // TODO(rnystrom): Each command should define the arguments it expects and
     // we can handle them generically here.