Initial work on refactorings.

pkg/analysis_services/lib/refactoring/progress_monitor.dart

+// Copyright (c) 2014, 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 services.refactoring.progress_monitor;
+
+
+/**
+ * A [ProgressMonitor] which ignores interactions.
+ */
+class NullProgressMonitor implements ProgressMonitor {

[Brian Wilkerson, 2014/08/11 16:27:47]

I don't understand the value of a progress monitor in the context of Server. Are
you thinking that we'll send status notifications to the client?

[scheglov, 2014/08/11 18:06:25]

Good point.
We don't need it / not useful in Dart.
Removing.

+  @override
+  bool get isCanceled => false;
+
+  @override
+  void beginTask(String name, int totalWork) {
+  }
+
+  @override
+  void done() {
+  }
+
+  @override
+  void internalWorked(double work) {
+  }
+
+  @override
+  void setCanceled() {
+  }
+
+  @override
+  void subTask(String name) {
+  }
+
+  @override
+  void worked(int work) {
+  }
+}
+
+
+/**
+ * This exception is thrown when the user cancels a long-running operation.
+ */
+class OperationCanceledException {
+  final String message;
+  OperationCanceledException([this.message = '']);
+  String toString() => "OperationCanceledException: $message";
+}
+
+
+/**
+ * An interface for monitoring the progress of an activity.
+ * Its methods are invoked by code that performs the activity.
+ */
+abstract class ProgressMonitor {
+  /**
+   * Returns whether cancelation of current operation has been requested.
+   *
+   * Long-running operations should poll to see if cancelation has been
+   * requested.
+   */
+  bool get isCanceled;
+
+  /**
+   * Notifies that the main task is beginning.
+   *
+   * This must only be called once on a given progress monitor instance.
+   */
+  void beginTask(String name, int totalWork);
+
+  /**
+   * Notifies that the main task is completed.
+   *
+   * This must only be called once on a given progress monitor instance.
+   */
+  void done();
+
+  /**
+   * Internal method to handle scaling correctly.
+   *
+   * This method must not be called by a client.
+   *
+   * Clients should always use the method [worked].
+   *
+   * [work] - the amount of work done.
+   */
+  void internalWorked(double work);
+
+  /**
+   * Sets the cancel state to the given value.
+   */
+  void setCanceled();
+
+  /**
+   * Notifies that a subtask of the main task is beginning.
+   *
+   * Subtasks are optional; the main task might not have subtasks.
+   *
+   * [name] - the name (or description) of the subtask.
+   */
+  void subTask(String name);
+
+  /**
+   * Notifies that a given number of work unit of the main task has been
+   * completed.
+   *
+   * Note that this amount represents an installment, as opposed to a cumulative
+   * amount of work done to date.
+   *
+   * [work] - a non-negative number of work units just completed.
+   */
+  void worked(int work);
+}