Make listDir and createSymlink synchronous in pub.

utils/pub/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 source;
 
 import 'dart:async';
 
 import 'package:pathos/path.dart' as path;
 
@@ skipping 95 matching lines @@
   /// Installs the package identified by [id] to the system cache. This is only
   /// called for sources with [shouldCache] set to true.
   ///
   /// By default, this uses [systemCacheDirectory] and [install].
   Future<Package> installToSystemCache(PackageId id) {
     var packageDir;
     return systemCacheDirectory(id).then((p) {
       packageDir = p;
 
       // See if it's already cached.
-      if (!dirExists(packageDir)) return false;
-
-      return _isCachedPackageCorrupted(packageDir).then((isCorrupted) {
-        if (!isCorrupted) return true;
-
+      if (dirExists(packageDir)) {
+        if (!_isCachedPackageCorrupted(packageDir)) return true;
         // Busted, so wipe out the package and reinstall.
         deleteEntry(packageDir);
-        return false;
-      });
-    }).then((isInstalled) {
-      if (isInstalled) return true;
+      }
+
       ensureDir(path.dirname(packageDir));
       return install(id, packageDir);
     }).then((found) {
       if (!found) throw 'Package $id not found.';
       return new Package.load(id.name, packageDir, systemCache.sources);
     });
   }
 
   /// Since pub generates symlinks that point into the system cache (in
   /// particular, targeting the "lib" directories of cached packages), it's
   /// possible to accidentally break cached packages if something traverses
   /// that symlink.
   ///
   /// This tries to determine if the cached package at [packageDir] has been
   /// corrupted. The heuristics are it is corrupted if any of the following are
   /// true:
   ///
   ///   * It has an empty "lib" directory.
   ///   * It has no pubspec.
-  Future<bool> _isCachedPackageCorrupted(String packageDir) {
-    return defer(() {
-      if (!fileExists(path.join(packageDir, "pubspec.yaml"))) return true;
+  bool _isCachedPackageCorrupted(String packageDir) {
+    if (!fileExists(path.join(packageDir, "pubspec.yaml"))) return true;
 
-      var libDir = path.join(packageDir, "lib");
-      if (dirExists(libDir)) {
-        return listDir(libDir).then((contents) => contents.length == 0);
-      }
+    var libDir = path.join(packageDir, "lib");
+    if (dirExists(libDir)) return listDir(libDir).length == 0;
 
-      // If we got here, it's OK.
-      return false;
-    });
+    // If we got here, it's OK.
+    return false;
   }
 
   /// Returns the directory in the system cache that the package identified by
   /// [id] should be installed to. This should return a path to a subdirectory
   /// of [systemCacheRoot].
   ///
   /// This doesn't need to be implemented if [shouldCache] is false.
   Future<String> systemCacheDirectory(PackageId id) {
     return new Future.immediateError(
         "systemCacheDirectory() must be implemented if shouldCache is true.");
@@ skipping 43 matching lines @@
   ///
   /// The returned [PackageId] may have a description field that's invalid
   /// according to [parseDescription], although it must still be serializable
   /// to JSON and YAML. It must also be equal to [id] according to
   /// [descriptionsEqual].
   ///
   /// By default, this just returns [id].
   Future<PackageId> resolveId(PackageId id) => new Future.immediate(id);
   
   /// Returns the [Package]s that have been installed in the system cache.
-  Future<List<Package>> getCachedPackages() {
+  List<Package> getCachedPackages() {
     if (shouldCache) throw "Source $name must implement this.";
   }
 
   /// Returns the source's name.
   String toString() => name;
 }