Initial task support

pkg/analyzer/lib/src/task/model.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 analyzer.src.task.model;
+
+import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
+import 'package:analyzer/src/task/inputs.dart';
+import 'package:analyzer/task/model.dart';
+
+/**
+ * A concrete implementation of a [ContributionPoint].
+ */
+class ContributionPointImpl<V> extends ResultDescriptorImpl<V> implements
+    ContributionPoint<V> {
+  /**
+   * The results that contribute to this result.
+   */
+  final List<ResultDescriptor> contributors = <ResultDescriptor>[];
+
+  /**
+   * Initialize a newly created contribution point to have the given [name].
+   */
+  ContributionPointImpl(String name) : super(name);
+
+  /**
+   * Record that the given analysis [result] contibutes to this result.
+   */
+  void recordContributor(ResultDescriptor<V> result) {
+    contributors.add(result);
+  }
+}
+
+/**
+ * A concrete implementation of a [ResultDescriptor].
+ */
+class ResultDescriptorImpl<V> implements ResultDescriptor<V> {
+  /**
+   * The name of the result, used for debugging.
+   */
+  final String name;
+
+  /**
+   * Initialize a newly created analysis result to have the given [name]. If a
+   * contribution point is specified, then this result will contribute to it.
+   */
+  ResultDescriptorImpl(this.name, {ContributionPoint contributesTo}) {
+    if (contributesTo is ContributionPointImpl) {
+      contributesTo.recordContributor(this);
+    }
+  }
+
+  @override
+  TaskInput<V> inputFor(AnalysisTarget target) =>
+      new SimpleTaskInput<V>(target, this);
+
+  @override
+  String toString() => name;
+}
+
+/**
+ * A concrete implementation of a [TaskDescriptor].
+ */
+class TaskDescriptorImpl implements TaskDescriptor {
+  /**
+   * The name of the described task, used for debugging.
+   */
+  final String name;
+
+  /**
+   * The function used to build the analysis task.
+   */
+  final BuildTask buildTask;
+
+  /**
+   * The function used to build the inputs to the task.
+   */
+  @override
+  final CreateTaskInputs createTaskInputs;
+
+  /**
+   * A list of the analysis results that will be computed by the described task.
+   */
+  @override
+  final List<ResultDescriptor> results;
+
+  /**
+   * Initialize a newly created task descriptor to have the given [name] and to
+   * describe a task that takes the inputs built using the given [createTaskInputs],
+   * and produces the given [results]. The [buildTask] will be used to create
+   * the instance of [AnalysisTask] thusly described.
+   */
+  TaskDescriptorImpl(this.name, this.buildTask, this.createTaskInputs,
+      this.results);
+
+  @override
+  AnalysisTask createTask(AnalysisContext context, AnalysisTarget target,
+      Map<String, dynamic> inputs) {
+    AnalysisTask task = buildTask(context, target);
+    task.inputs = inputs;
+    return task;
+  }
+
+  @override
+  String toString() => name;
+}