Initial task support

pkg/analyzer/lib/src/task/manager.dart

Index: pkg/analyzer/lib/src/task/manager.dart
diff --git a/pkg/analyzer/lib/src/task/manager.dart b/pkg/analyzer/lib/src/task/manager.dart
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+++ b/pkg/analyzer/lib/src/task/manager.dart
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+// 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.manager;
+
+import 'dart:collection';
+
+import 'package:analyzer/src/generated/java_engine.dart';
+import 'package:analyzer/task/model.dart';
+
+/**
+ * An object that manages the information about the tasks that have been
+ * defined.
+ */
+class TaskManager {
+  /**
+   * A table mapping [ResultDescriptor]s to a list of [TaskDescriptor]s
+   * for the tasks that can be used to compute the result.
+   */
+  Map<ResultDescriptor, List<TaskDescriptor>> taskMap =
+      new HashMap<ResultDescriptor, List<TaskDescriptor>>();
+
+  /**
+   * A list of the results that are to be computed for all sources within an
+   * analysis root.
+   */
+  Set<ResultDescriptor> generalResults = new Set<ResultDescriptor>();
+
+  /**
+   * A list of the results that are to be computed for priority sources.
+   */
+  Set<ResultDescriptor> priorityResults = new Set<ResultDescriptor>();
+
+  /**
+   * Add the given [result] to the list of results that are to be computed for
+   * all sources within an analysis root.
+   */
+  void addGeneralResult(ResultDescriptor result) {
+    generalResults.add(result);
+  }
+
+  /**
+   * Add the given [result] to the list of results that are to be computed for
+   * priority sources.
+   */
+  void addPriorityResult(ResultDescriptor result) {
+    priorityResults.add(result);
+  }
+
+  /**
+   * Add the given [descriptor] to the list of analysis task descriptors that
+   * can be used to compute analysis results.
+   */
+  void addTaskDescriptor(TaskDescriptor descriptor) {
+    descriptor.results.forEach((ResultDescriptor result) {
+      //
+      // Add the result to the task map.
+      //
+      List<TaskDescriptor> descriptors = taskMap[result];
+      if (descriptors == null) {
+        descriptors = <TaskDescriptor>[];
+        taskMap[result] = descriptors;
+      }
+      descriptors.add(descriptor);
+    });
+  }
+
+  /**
+   * Find a task that will compute the given [result] for the given [target].
+   */
+  TaskDescriptor findTask(AnalysisTarget target, ResultDescriptor result) {
+    List<TaskDescriptor> descriptors = taskMap[result];
+    if (descriptors == null) {
+      throw new AnalysisException(
+          'No tasks registered to compute $result for $target');
+    }
+    return _findBestTask(descriptors);
+  }
+
+  /**
+   * Remove the given [result] from the list of results that are to be computed
+   * for all sources within an analysis root.
+   */
+  void removeGeneralResult(ResultDescriptor result) {
+    generalResults.remove(result);
+  }
+
+  /**
+   * Remove the given [result] from the list of results that are to be computed
+   * for priority sources.
+   */
+  void removePriorityResult(ResultDescriptor result) {
+    priorityResults.remove(result);
+  }
+
+  /**
+   * Given a list of task [descriptors] that can be used to compute some
+   * unspecified result, return the descriptor that will compute the result with
+   * the least amount of work.
+   */
+  TaskDescriptor _findBestTask(List<TaskDescriptor> descriptors) {
+    // TODO(brianwilkerson) Improve this implementation.
+    return descriptors[0];
+  }
+}