Use environment variables to find the Dart SDK and the Pub cache directory.

utils/pub/pub.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.
 
 /**
  * The main entrypoint for the pub command line application.
  */
 #library('pub');
 
 #import('../../lib/args/args.dart');
+#import('dart:io');
 #import('io.dart');
 #import('command_install.dart');
 #import('command_list.dart');
 #import('command_update.dart');
 #import('command_version.dart');
 #import('entrypoint.dart');
 #import('git_source.dart');
 #import('package.dart');
 #import('pubspec.dart');
 #import('repo_source.dart');
@@ skipping 15 matching lines @@
     'install': new InstallCommand(),
     'update': new UpdateCommand(),
     'version': new VersionCommand()
   };
 
   var parser = new ArgParser();
   parser.addFlag('help', abbr: 'h', negatable: false,
     help: 'Prints this usage information');
   parser.addFlag('version', negatable: false,
     help: 'Prints the version of Pub');
-  // TODO(rnystrom): Hack. These are temporary options to allow the pub tests to
-  // pass in relevant paths. Eventually these should be environment variables.
-  parser.addOption('cachedir', help: 'The directory containing the system-wide '
-    'Pub cache');
-  parser.addOption('sdkdir', help: 'The directory containing the Dart SDK');
   parser.addFlag('trace', help: 'Prints a stack trace when an error occurs');
 
   var globalOptions;
   try {
     globalOptions = parser.parse(new Options().arguments);
   } catch (ArgFormatException e) {
     printUsage(parser, commands, description: e.message);
     return;
   }
 
   if (globalOptions['version']) {
     printVersion();
     return;
   }
 
   if (globalOptions['help'] || globalOptions.rest.isEmpty()) {
     printUsage(parser, commands);
     return;
   }
 
-  var cache = new SystemCache(globalOptions['cachedir']);
-  cache.register(new SdkSource(globalOptions['sdkdir']));
+  // TODO(nweiz): Have a fallback for this this out automatically once 1145 is
+  // fixed.
+  var sdkDir = Platform.environment['DART_SDK'];
+  var cacheDir;
+  if (Platform.environment.containsKey('PUB_CACHE')) {
+    cacheDir = Platform.environment['PUB_CACHE'];
+  } else {
+    // TODO(nweiz): Choose a better default for Windows.
+    cacheDir = '${Platform.environment['HOME']}/.pub-cache';
+  }
+
+  var cache = new SystemCache(cacheDir);
+  cache.register(new SdkSource(sdkDir));
   cache.register(new GitSource());
   cache.register(new RepoSource());
   // TODO(nweiz): Make 'repo' the default once pub.dartlang.org exists
   cache.sources.setDefault('sdk');
 
   // Select the command.
   var command = commands[globalOptions.rest[0]];
   if (command == null) {
     printError('Unknown command "${globalOptions.rest[0]}".');
     printError('Run "pub help" to see available commands.');
@@ skipping 94 matching lines @@
     future.handleException((e) => handleError(e, future.stackTrace));
   }
 
   /**
    * Override this to perform the specific command. Return a future that
    * completes when the command is done or fails if the command fails. If the
    * command is synchronous, it may return `null`.
    */
   abstract Future onRun();
 }