Add DartWorkManager to manage Dart-specific results computation scheduling.

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

Index: pkg/analyzer/lib/src/task/dart_work_manager.dart
diff --git a/pkg/analyzer/lib/src/task/dart_work_manager.dart b/pkg/analyzer/lib/src/task/dart_work_manager.dart
new file mode 100644
index 0000000000000000000000000000000000000000..b91c0b7ff9bef67fc59f0a1db50f98a8aadb0600
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+++ b/pkg/analyzer/lib/src/task/dart_work_manager.dart
@@ -0,0 +1,135 @@
+// 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.dart_work_manager;
+
+import 'dart:collection';
+
+import 'package:analyzer/src/context/cache.dart';
+import 'package:analyzer/src/generated/engine.dart'
+    show AnalysisEngine, CacheState, InternalAnalysisContext;
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/task/dart.dart';
+import 'package:analyzer/src/task/driver.dart';
+import 'package:analyzer/task/dart.dart';
+import 'package:analyzer/task/model.dart';
+
+/**
+ * The manager for Dart specific analysis.
+ */
+class DartWorkManager implements WorkManager {
+  final InternalAnalysisContext context;
+
+  /**
+   * The explicit sources to analyze.
+   */
+  final HashSet<Source> explicitSources = new HashSet<Source>();

[Brian Wilkerson, 2015/05/09 17:22:00]

The sets of 'explicitSources', 'librarySources' and 'partSources' are being
maintained (added to and removed from), but are not being used (accessed) here.
I don't understand their purpose.

[scheglov, 2015/05/09 23:20:17]

Well, you're right that they're not used now.
But:

1. There is AnalysisContext.librarySources, which can be implemented using
DartWorkManager.
2. "partSources" can be repurposed to Map<Part, List<Library>> and be used for
implementing AnalysisContext.getLibrariesContaining() later.

I cannot think out a good use of "explicitSources" right now :-)
Removing it for now.

+
+  /**
+   * The known library source.
+   */
+  final HashSet<Source> librarySources = new HashSet<Source>();
+
+  /**
+   * The know part sources.
+   */
+  final HashSet<Source> partSources = new HashSet<Source>();
+
+  /**
+   * The sources whose kind we don't know yet.
+   */
+  final LinkedHashSet<Source> unknownSourceQueue = new LinkedHashSet<Source>();
+
+  /**
+   * The queue of library sources to process.
+   */
+  final LinkedHashSet<Source> librarySourceQueue = new LinkedHashSet<Source>();
+
+  /**
+   * Initialize a newly created manager.
+   */
+  DartWorkManager(this.context);
+
+  /**
+   * Notifies the manager about changes in the explicit source list.
+   */
+  void applyChange(List<Source> addedSources, List<Source> changedSources,
+      List<Source> removedSources) {
+    addedSources = addedSources.where(_isDartSource).toList();
+    changedSources = changedSources.where(_isDartSource).toList();
+    removedSources = removedSources.where(_isDartSource).toList();
+    // explicit
+    explicitSources.addAll(addedSources);
+    explicitSources.removeAll(removedSources);
+    // library
+    librarySources.removeAll(changedSources);
+    librarySources.removeAll(removedSources);
+    // part
+    partSources.removeAll(changedSources);
+    partSources.removeAll(removedSources);
+    // unknown queue
+    unknownSourceQueue.addAll(addedSources);
+    unknownSourceQueue.addAll(changedSources);
+    unknownSourceQueue.removeAll(removedSources);
+    // library queue
+    librarySourceQueue.removeAll(changedSources);
+    librarySourceQueue.removeAll(removedSources);
+  }
+
+  @override
+  TargetedResult getNextResult() {
+    // Try to find a new library to analyze.
+    while (librarySourceQueue.isNotEmpty) {
+      Source librarySource = librarySourceQueue.first;
+      CacheEntry entry = context.getCacheEntry(librarySource);
+      CacheState state = entry.getState(LIBRARY_ERRORS_READY);
+      // Maybe done with this library.
+      if (state == CacheState.VALID || state == CacheState.ERROR) {
+        librarySourceQueue.remove(librarySource);
+        continue;
+      }
+      // Analyze this library.
+      return new TargetedResult(librarySource, LIBRARY_ERRORS_READY);
+    }
+    // No libraries in the queue, check whether there are sources to organize.
+    while (unknownSourceQueue.isNotEmpty) {
+      Source source = unknownSourceQueue.first;
+      CacheEntry entry = context.getCacheEntry(source);
+      CacheState state = entry.getState(SOURCE_KIND);
+      // Maybe done with this source.
+      if (state == CacheState.VALID || state == CacheState.ERROR) {
+        unknownSourceQueue.remove(source);
+        continue;
+      }
+      // Compute the kind of this source.
+      return new TargetedResult(source, SOURCE_KIND);
+    }
+    // No results to compute.
+    return null;

[Brian Wilkerson, 2015/05/09 17:22:00]

The old work manager also maintained a queue of part sources (removing them when
a library was found that contained them). I don't think I got it implemented,
but the plan was always to add an analysis error for parts that remained in the
queue after all libraries had been processed because they would be parts that
were not included in any library. Perhaps a TODO comment to remind us to add
this.

[scheglov, 2015/05/09 23:20:17]

Good idea.
I've added a TODO comment.

+  }
+
+  @override
+  void resultsComputed(
+      AnalysisTarget target, Map<ResultDescriptor, dynamic> outputs) {
+    // Organize sources.
+    if (_isDartSource(target)) {
+      SourceKind kind = outputs[SOURCE_KIND];
+      if (kind != null) {
+        unknownSourceQueue.remove(target);
+        if (kind == SourceKind.PART) {
+          librarySources.remove(target);
+          partSources.add(target);
+        } else {
+          librarySources.add(target);
+          partSources.remove(target);
+          librarySourceQueue.add(target);
+        }
+      }
+    }
+  }
+
+  bool _isDartSource(AnalysisTarget target) {
+    return target is Source && AnalysisEngine.isDartFileName(target.fullName);
+  }
+}