Get rid of join() and encapsulate File and Directory in io.dart.

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/path/lib/path.dart' as path;
 
@@ skipping 35 matching lines @@
   /// directory, or have already been installed.
   final _installs = new Map<PackageId, Future<PackageId>>();
 
   /// Loads the entrypoint from a package at [rootDir].
   Entrypoint(String rootDir, SystemCache cache)
       : root = new Package.load(null, rootDir, cache.sources),
         cache = cache;
 
   // TODO(rnystrom): Make this path configurable.
   /// The path to the entrypoint's "packages" directory.
-  String get packagesDir => join(root.dir, 'packages');
+  String get packagesDir => path.join(root.dir, 'packages');
 
   /// Ensures that the package identified by [id] is installed to the directory.
   /// Returns the resolved [PackageId].
   ///
   /// If this completes successfully, the package is guaranteed to be importable
   /// using the `package:` scheme.
   ///
   /// This will automatically install the package to the system-wide cache as
   /// well if it requires network access to retrieve (specifically, if
   /// `id.source.shouldCache` is true).
   ///
   /// See also [installDependencies].
   Future<PackageId> install(PackageId id) {
     var pendingOrCompleted = _installs[id];
     if (pendingOrCompleted != null) return pendingOrCompleted;
 
-    var packageDir = join(packagesDir, id.name);
+    var packageDir = path.join(packagesDir, id.name);
     var future = defer(() {
       ensureDir(path.dirname(packageDir));
       if (!dirExists(packageDir)) return;
 
       // 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.");
       return deleteDir(packageDir);
     }).then((_) {
       if (id.source.shouldCache) {
@@ skipping 116 matching lines @@
                 "SDK\n"
             "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 = join(root.dir, 'pubspec.lock');
+    var lockFilePath = path.join(root.dir, 'pubspec.lock');
     if (!fileExists(lockFilePath)) return new LockFile.empty();
     return new LockFile.parse(readTextFile(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;
     }
 
-    var lockFilePath = join(root.dir, 'pubspec.lock');
+    var lockFilePath = path.join(root.dir, 'pubspec.lock');
     writeTextFile(lockFilePath, lockFile.serialize());
   }
 
   /// Installs a self-referential symlink in the `packages` directory that will
   /// allow a package to import its own files using `package:`.
   Future _installSelfReference(_) {
     return defer(() {
-      var linkPath = join(packagesDir, root.name);
+      var linkPath = path.join(packagesDir, root.name);
       // Create the symlink if it doesn't exist.
       if (entryExists(linkPath)) return;
       ensureDir(packagesDir);
       return createPackageSymlink(root.name, root.dir, linkPath,
           isSelfLink: true);
     });
   }
 
   /// If `bin/`, `test/`, or `example/` directories exist, symlink `packages/`
   /// into them so that their entrypoints can be run. Do the same for any
   /// subdirectories of `test/` and `example/`.
   Future _linkSecondaryPackageDirs(_) {
-    var binDir = join(root.dir, 'bin');
-    var exampleDir = join(root.dir, 'example');
-    var testDir = join(root.dir, 'test');
-    var toolDir = join(root.dir, 'tool');
-    var webDir = join(root.dir, 'web');
+    var binDir = path.join(root.dir, 'bin');
+    var exampleDir = path.join(root.dir, 'example');
+    var testDir = path.join(root.dir, 'test');
+    var toolDir = path.join(root.dir, 'tool');
+    var webDir = path.join(root.dir, 'web');
     return defer(() {
       if (!dirExists(binDir)) return;
       return _linkSecondaryPackageDir(binDir);
     }).then((_) => _linkSecondaryPackageDirsRecursively(exampleDir))
       .then((_) => _linkSecondaryPackageDirsRecursively(testDir))
       .then((_) => _linkSecondaryPackageDirsRecursively(toolDir))
       .then((_) => _linkSecondaryPackageDirsRecursively(webDir));
   }
 
   /// Creates a symlink to the `packages` directory in [dir] and all its
@@ skipping 29 matching lines @@
           fileAndSubfiles.addAll(subfiles);
           return fileAndSubfiles;
         });
       }));
     }).then(flatten);
   }
 
   /// Creates a symlink to the `packages` directory in [dir] if none exists.
   Future _linkSecondaryPackageDir(String dir) {
     return defer(() {
-      var to = join(dir, 'packages');
+      var to = path.join(dir, 'packages');
       if (entryExists(to)) return;
       return createSymlink(packagesDir, to);
     });
   }
 }