Clean up the semantics of io.dart operations w.r.t. symlinks.

utils/pub/entrypoint.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 entrypoint;
 
 import 'dart:async';
 
 import '../../pkg/pathos/lib/path.dart' as path;
 
@@ skipping 56 matching lines @@
   ///
   /// See also [installDependencies].
   Future<PackageId> install(PackageId id) {
     var pendingOrCompleted = _installs[id];
     if (pendingOrCompleted != null) return pendingOrCompleted;
 
     var packageDir = path.join(packagesDir, id.name);
     var future = defer(() {
       ensureDir(path.dirname(packageDir));
 
-      if (dirExists(packageDir)) {
+      if (entryExists(packageDir)) {
         // TODO(nweiz): figure out when to actually delete the directory, and
         // when we can just re-use the existing symlink.
         log.fine("Deleting package directory for ${id.name} before install.");
-        deleteDir(packageDir);
+        deleteEntry(packageDir);
       }
 
       if (id.source.shouldCache) {
         return cache.install(id).then(
             (pkg) => createPackageSymlink(id.name, pkg.dir, packageDir));
       } else {
         return id.source.install(id, packageDir).then((found) {
           if (found) return null;
           // TODO(nweiz): More robust error-handling.
           throw 'Package ${id.name} not found in source "${id.source.name}".';
@@ skipping 111 matching lines @@
             "or adding a version constraint to use an older version of a "
                 "package.");
       }
     });
   }
 
   /// Loads the list of concrete package versions from the `pubspec.lock`, if it
   /// exists. If it doesn't, this completes to an empty [LockFile].
   LockFile loadLockFile() {
     var lockFilePath = path.join(root.dir, 'pubspec.lock');
-    if (!fileExists(lockFilePath)) return new LockFile.empty();
+    if (!entryExists(lockFilePath)) return new LockFile.empty();
     return new LockFile.load(lockFilePath, cache.sources);
   }
 
   /// Saves a list of concrete package versions to the `pubspec.lock` file.
   void _saveLockFile(List<PackageId> packageIds) {
     var lockFile = new LockFile.empty();
     for (var id in packageIds) {
       if (!id.isRoot) lockFile.packages[id.name] = id;
     }
 
@@ skipping 67 matching lines @@
         });
       }).toList());
     }).then(flatten);
   }
 
   /// Creates a symlink to the `packages` directory in [dir]. Will replace one
   /// if already there.
   Future _linkSecondaryPackageDir(String dir) {
     return defer(() {
       var symlink = path.join(dir, 'packages');
-      // The order of if tests is significant here. fileExists() will return
-      // true for a symlink (broken or not) but deleteFile() cannot be used
-      // to delete a broken symlink on Windows. So we test for the directory
-      // first since deleteDir() does work on symlinks.
-      // TODO(rnystrom): Make deleteFile() work for symlinks on Windows so this
-      // doesn't matter.
-      if (dirExists(symlink)) {
-        deleteDir(symlink);
-      } else if (fileExists(symlink)) {
-        deleteFile(symlink);
-      }
+      if (entryExists(symlink)) deleteEntry(symlink);
       return createSymlink(packagesDir, symlink, relative: true);
     });
   }
 }