Make a bunch of stuff in pub synchronous.

utils/pub/package.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 package;
 
 import 'dart:async';
 import 'io.dart';
 import 'pubspec.dart';
 import 'source.dart';
 import 'source_registry.dart';
 import 'version.dart';
 
 final _README_REGEXP = new RegExp(r"^README($|\.)", caseSensitive: false);
 
 /// A named, versioned, unit of code and resource reuse.
 class Package {
-  /// Loads the package whose root directory is [packageDir]. [name] is the
-  /// expected name of that package (e.g. the name given in the dependency), or
-  /// null if the package being loaded is the entrypoint package.
-  static Future<Package> load(String name, String packageDir,
-      SourceRegistry sources) {
-    var pubspecPath = join(packageDir, 'pubspec.yaml');
-
-    return fileExists(pubspecPath).then((exists) {
-      if (!exists) throw new PubspecNotFoundException(name);
-      return readTextFile(pubspecPath);
-    }).then((contents) {
-      try {
-        var pubspec = new Pubspec.parse(contents, sources);
-
-        if (pubspec.name == null) throw new PubspecHasNoNameException(name);
-        if (name != null && pubspec.name != name) {
-          throw new PubspecNameMismatchException(name, pubspec.name);
-        }
-        return new Package._(packageDir, pubspec);
-      } on FormatException catch (ex) {
-        throw 'Could not parse $pubspecPath:\n${ex.message}';
-      }
-    });
-  }
-
   /// The path to the directory containing the package.
   final String dir;
 
   /// The name of the package.
   String get name {
     if (pubspec.name != null) return pubspec.name;
     if (dir != null) return basename(dir);
     return null;
   }
 
@@ skipping 20 matching lines @@
       return readmes.min((readme1, readme2) {
         var extensions1 = ".".allMatches(readme1).length;
         var extensions2 = ".".allMatches(readme2).length;
         var comparison = extensions1.compareTo(extensions2);
         if (comparison != 0) return comparison;
         return readme1.compareTo(readme2);
       });
     });
   }
 
+  /// Loads the package whose root directory is [packageDir]. [name] is the
+  /// expected name of that package (e.g. the name given in the dependency), or
+  /// `null` if the package being loaded is the entrypoint package.
+  factory Package(String name, String packageDir, SourceRegistry sources) {
+    var pubspecPath = join(packageDir, 'pubspec.yaml');
+    if (!fileExists(pubspecPath)) throw new PubspecNotFoundException(name);
+
+    try {
+      var pubspec = new Pubspec.parse(readTextFile(pubspecPath), sources);
+
+      if (pubspec.name == null) {
+        throw new PubspecHasNoNameException(name);
+      }
+
+      if (name != null && pubspec.name != name) {
+        throw new PubspecNameMismatchException(name, pubspec.name);
+      }
+
+      return new Package._(packageDir, pubspec);
+    } on FormatException catch (ex) {
+      throw 'Could not parse $pubspecPath:\n${ex.message}';
+    }
+  }
+
   /// Constructs a package with the given pubspec. The package will have no
   /// directory associated with it.
   Package.inMemory(this.pubspec)
     : dir = null;
 
   /// Constructs a package. This should not be called directly. Instead, acquire
   /// packages from [load()].
   Package._(this.dir, this.pubspec);
 
   /// Returns a debug string for the package.
@@ skipping 130 matching lines @@
 
 class PubspecNameMismatchException implements Exception {
   final String expectedName;
   final String actualName;
 
   PubspecNameMismatchException(this.expectedName, this.actualName);
 
   String toString() => 'The name you specified for your dependency, '
     '"$expectedName", doesn\'t match the name "$actualName" in its pubspec.';
 }