Roll Observatory packages and add a roll script

plugin/lib/src/plugin_impl.dart

-// Copyright (c) 2015, 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 plugin.src.plugin_impl;
-
-import 'dart:collection';
-
-import 'package:plugin/manager.dart';
-import 'package:plugin/plugin.dart';
-
-/**
- * A concrete implementation of an [ExtensionManager].
- */
-class ExtensionManagerImpl implements ExtensionManager {
-  /**
-   * A table mapping the id's of extension points to the corresponding
-   * extension points.
-   */
-  Map<String, ExtensionPointImpl> extensionPoints =
-      new HashMap<String, ExtensionPointImpl>();
-
-  @override
-  void processPlugins(List<Plugin> plugins) {
-    for (Plugin plugin in plugins) {
-      plugin.registerExtensionPoints((String identifier,
-              [ValidateExtension validateExtension]) =>
-          registerExtensionPoint(plugin, identifier, validateExtension));
-    }
-    for (Plugin plugin in plugins) {
-      plugin.registerExtensions(registerExtension);
-    }
-  }
-
-  /**
-   * Register an [extension] to the extension point with the given unique
-   * [identifier].
-   */
-  void registerExtension(String identifier, Object extension) {
-    ExtensionPointImpl extensionPoint = extensionPoints[identifier];
-    if (extensionPoint == null) {
-      throw new ExtensionError(
-          'There is no extension point with the id "$identifier"');
-    }
-    extensionPoint.add(extension);
-  }
-
-  /**
-   * Register an extension point being defined by the given [plugin] with the
-   * given simple [identifier] and [validateExtension].
-   */
-  ExtensionPoint registerExtensionPoint(
-      Plugin plugin, String identifier, ValidateExtension validateExtension) {
-    String uniqueIdentifier = Plugin.buildUniqueIdentifier(plugin, identifier);
-    if (extensionPoints.containsKey(uniqueIdentifier)) {
-      throw new ExtensionError(
-          'There is already an extension point with the id "$identifier"');
-    }
-    ExtensionPointImpl extensionPoint =
-        new ExtensionPointImpl(plugin, identifier, validateExtension);
-    extensionPoints[uniqueIdentifier] = extensionPoint;
-    return extensionPoint;
-  }
-}
-
-/**
- * A concrete representation of an extension point.
- */
-class ExtensionPointImpl implements ExtensionPoint {
-  @override
-  final Plugin plugin;
-
-  @override
-  final String simpleIdentifier;
-
-  /**
-   * The function used to validate extensions to this extension point.
-   */
-  final ValidateExtension validateExtension;
-
-  /**
-   * The list of extensions to this extension point.
-   */
-  final List<Object> _extensions = <Object>[];
-
-  /**
-   * Initialize a newly create extension point to belong to the given [plugin]
-   * and have the given [simpleIdentifier]. If [validateExtension] is non-`null`
-   * it will be used to validate extensions associated with this extension
-   * point.
-   */
-  ExtensionPointImpl(
-      this.plugin, this.simpleIdentifier, this.validateExtension);
-
-  /**
-   * Return a list containing all of the extensions that have been registered
-   * for this extension point.
-   */
-  List<Object> get extensions => new UnmodifiableListView(_extensions);
-
-  /**
-   * Return the identifier used to uniquely identify this extension point. The
-   * unique identifier is the identifier for the plugin, followed by a period
-   * (`.`), followed by the [simpleIdentifier] for the extension point.
-   */
-  String get uniqueIdentifier =>
-      Plugin.buildUniqueIdentifier(plugin, simpleIdentifier);
-
-  /**
-   * Validate that the given [extension] is appropriate for this extension
-   * point, and if it is then add it to the list of registered exceptions.
-   */
-  void add(Object extension) {
-    if (validateExtension != null) {
-      validateExtension(extension);
-    }
-    _extensions.add(extension);
-  }
-}