Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/analyzer/lib/src/context/context.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.context.context;
+
+import 'dart:async';
+import 'dart:collection';
+
+import 'package:analyzer/instrumentation/instrumentation.dart';
+import 'package:analyzer/plugin/task.dart';
+import 'package:analyzer/src/cancelable_future.dart';
+import 'package:analyzer/src/context/cache.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/constant.dart';
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/engine.dart'
+    hide
+        AnalysisCache,
+        CachePartition,
+        SdkCachePartition,
+        UniversalCachePartition,
+        WorkManager;
+import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/html.dart' as ht show HtmlUnit;
+import 'package:analyzer/src/generated/incremental_resolver.dart';
+import 'package:analyzer/src/generated/java_core.dart';
+import 'package:analyzer/src/generated/java_engine.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/scanner.dart';
+import 'package:analyzer/src/generated/sdk.dart' show DartSdk;
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_collection.dart';
+import 'package:analyzer/src/task/dart.dart';
+import 'package:analyzer/src/task/dart_work_manager.dart';
+import 'package:analyzer/src/task/driver.dart';
+import 'package:analyzer/src/task/incremental_element_builder.dart';
+import 'package:analyzer/src/task/manager.dart';
+import 'package:analyzer/task/dart.dart';
+import 'package:analyzer/task/general.dart';
+import 'package:analyzer/task/html.dart';
+import 'package:analyzer/task/model.dart';
+import 'package:html/dom.dart' show Document;
+
+/**
+ * Type of callback functions used by PendingFuture. Functions of this type
+ * should perform a computation based on the data in [entry] and return it. If
+ * the computation can't be performed yet because more analysis is needed,
+ * `null` should be returned.
+ *
+ * The function may also throw an exception, in which case the corresponding
+ * future will be completed with failure.
+ *
+ * Because this function is called while the state of analysis is being updated,
+ * it should be free of side effects so that it doesn't cause reentrant changes
+ * to the analysis state.
+ */
+typedef T PendingFutureComputer<T>(CacheEntry entry);
+
+/**
+ * An [AnalysisContext] in which analysis can be performed.
+ */
+class AnalysisContextImpl implements InternalAnalysisContext {
+  /**
+   * The next context identifier.
+   */
+  static int _NEXT_ID = 0;
+
+  /**
+   * The unique identifier of this context.
+   */
+  final int _id = _NEXT_ID++;
+
+  /**
+   * A client-provided name used to identify this context, or `null` if the
+   * client has not provided a name.
+   */
+  String name;
+
+  /**
+   * The set of analysis options controlling the behavior of this context.
+   */
+  AnalysisOptionsImpl _options = new AnalysisOptionsImpl();
+
+  /**
+   * A flag indicating whether this context is disposed.
+   */
+  bool _disposed = false;
+
+  /**
+   * A cache of content used to override the default content of a source.
+   */
+  ContentCache _contentCache = new ContentCache();
+
+  /**
+   * The source factory used to create the sources that can be analyzed in this
+   * context.
+   */
+  SourceFactory _sourceFactory;
+
+  /**
+   * The set of declared variables used when computing constant values.
+   */
+  DeclaredVariables _declaredVariables = new DeclaredVariables();
+
+  /**
+   * The partition that contains analysis results that are not shared with other
+   * contexts.
+   */
+  CachePartition _privatePartition;
+
+  /**
+   * The cache in which information about the results associated with targets
+   * are stored.
+   */
+  AnalysisCache _cache;
+
+  /**
+   * The task manager used to manage the tasks used to analyze code.
+   */
+  TaskManager _taskManager;
+
+  /**
+   * A list of all [WorkManager]s used by this context.
+   */
+  final List<WorkManager> workManagers = <WorkManager>[];
+
+  /**
+   * The [DartWorkManager] instance that performs Dart specific scheduling.
+   */
+  DartWorkManager dartWorkManager;
+
+  /**
+   * The analysis driver used to perform analysis.
+   */
+  AnalysisDriver driver;
+
+  /**
+   * A list containing sources for which data should not be flushed.
+   */
+  List<Source> _priorityOrder = <Source>[];
+
+  /**
+   * A map from all sources for which there are futures pending to a list of
+   * the corresponding PendingFuture objects.  These sources will be analyzed
+   * in the same way as priority sources, except with higher priority.
+   */
+  HashMap<AnalysisTarget, List<PendingFuture>> _pendingFutureTargets =
+      new HashMap<AnalysisTarget, List<PendingFuture>>();
+
+  /**
+   * A table mapping sources to the change notices that are waiting to be
+   * returned related to that source.
+   */
+  HashMap<Source, ChangeNoticeImpl> _pendingNotices =
+      new HashMap<Source, ChangeNoticeImpl>();
+
+  /**
+   * The [TypeProvider] for this context, `null` if not yet created.
+   */
+  TypeProvider _typeProvider;
+
+  /**
+   * The controller for sending [SourcesChangedEvent]s.
+   */
+  StreamController<SourcesChangedEvent> _onSourcesChangedController;
+
+  /**
+   * A subscription for a stream of events indicating when files are (and are
+   * not) being implicitly analyzed.
+   */
+  StreamController<ImplicitAnalysisEvent> _implicitAnalysisEventsController;
+
+  /**
+   * The listeners that are to be notified when various analysis results are
+   * produced in this context.
+   */
+  List<AnalysisListener> _listeners = new List<AnalysisListener>();
+
+  /**
+   * The most recently incrementally resolved source, or `null` when it was
+   * already validated, or the most recent change was not incrementally resolved.
+   */
+  Source incrementalResolutionValidation_lastUnitSource;
+
+  /**
+   * The most recently incrementally resolved library source, or `null` when it
+   * was already validated, or the most recent change was not incrementally
+   * resolved.
+   */
+  Source incrementalResolutionValidation_lastLibrarySource;
+
+  /**
+   * The result of incremental resolution result of
+   * [incrementalResolutionValidation_lastSource].
+   */
+  CompilationUnit incrementalResolutionValidation_lastUnit;
+
+  /**
+   * A factory to override how the [ResolverVisitor] is created.
+   */
+  ResolverVisitorFactory resolverVisitorFactory;
+
+  /**
+   * A factory to override how the [TypeResolverVisitor] is created.
+   */
+  TypeResolverVisitorFactory typeResolverVisitorFactory;
+
+  /**
+   * A factory to override how [LibraryResolver] is created.
+   */
+  LibraryResolverFactory libraryResolverFactory;
+
+  /**
+   * Initialize a newly created analysis context.
+   */
+  AnalysisContextImpl() {
+    _privatePartition = new UniversalCachePartition(this);
+    _cache = createCacheFromSourceFactory(null);
+    _taskManager = AnalysisEngine.instance.taskManager;
+    for (WorkManagerFactory factory
+        in AnalysisEngine.instance.enginePlugin.workManagerFactories) {
+      WorkManager workManager = factory(this);
+      if (workManager != null) {
+        workManagers.add(workManager);
+        if (workManager is DartWorkManager) {
+          dartWorkManager = workManager;
+        }
+      }
+    }
+    driver = new AnalysisDriver(_taskManager, workManagers, this);
+    _onSourcesChangedController =
+        new StreamController<SourcesChangedEvent>.broadcast();
+    _implicitAnalysisEventsController =
+        new StreamController<ImplicitAnalysisEvent>.broadcast();
+  }
+
+  @override
+  AnalysisCache get analysisCache => _cache;
+
+  @override
+  AnalysisOptions get analysisOptions => _options;
+
+  @override
+  void set analysisOptions(AnalysisOptions options) {
+    bool needsRecompute = this._options.analyzeFunctionBodiesPredicate !=
+            options.analyzeFunctionBodiesPredicate ||
+        this._options.generateImplicitErrors !=
+            options.generateImplicitErrors ||
+        this._options.generateSdkErrors != options.generateSdkErrors ||
+        this._options.dart2jsHint != options.dart2jsHint ||
+        (this._options.hint && !options.hint) ||
+        (this._options.lint && !options.lint) ||
+        this._options.preserveComments != options.preserveComments ||
+        this._options.enableStrictCallChecks !=
+            options.enableStrictCallChecks ||
+        this._options.enableSuperMixins != options.enableSuperMixins;
+    int cacheSize = options.cacheSize;
+    if (this._options.cacheSize != cacheSize) {
+      this._options.cacheSize = cacheSize;
+    }
+    this._options.analyzeFunctionBodiesPredicate =
+        options.analyzeFunctionBodiesPredicate;
+    this._options.generateImplicitErrors = options.generateImplicitErrors;
+    this._options.generateSdkErrors = options.generateSdkErrors;
+    this._options.dart2jsHint = options.dart2jsHint;
+    this._options.enableStrictCallChecks = options.enableStrictCallChecks;
+    this._options.enableSuperMixins = options.enableSuperMixins;
+    this._options.hint = options.hint;
+    this._options.incremental = options.incremental;
+    this._options.incrementalApi = options.incrementalApi;
+    this._options.incrementalValidation = options.incrementalValidation;
+    this._options.lint = options.lint;
+    this._options.preserveComments = options.preserveComments;
+    if (needsRecompute) {
+      for (WorkManager workManager in workManagers) {
+        workManager.onAnalysisOptionsChanged();
+      }
+    }
+  }
+
+  @override
+  void set analysisPriorityOrder(List<Source> sources) {
+    if (sources == null || sources.isEmpty) {
+      _priorityOrder = Source.EMPTY_LIST;
+    } else {
+      while (sources.remove(null)) {
+        // Nothing else to do.
+      }
+      if (sources.isEmpty) {
+        _priorityOrder = Source.EMPTY_LIST;
+      } else {
+        _priorityOrder = sources;
+      }
+    }
+    for (WorkManager workManager in workManagers) {
+      workManager.applyPriorityTargets(_priorityOrder);
+    }
+  }
+
+  @override
+  set contentCache(ContentCache value) {
+    _contentCache = value;
+  }
+
+  @override
+  DeclaredVariables get declaredVariables => _declaredVariables;
+
+  @override
+  List<AnalysisTarget> get explicitTargets {
+    List<AnalysisTarget> targets = <AnalysisTarget>[];
+    MapIterator<AnalysisTarget, CacheEntry> iterator = _cache.iterator();
+    while (iterator.moveNext()) {
+      if (iterator.value.explicitlyAdded) {
+        targets.add(iterator.key);
+      }
+    }
+    return targets;
+  }
+
+  @override
+  List<Source> get htmlSources => _getSources(SourceKind.HTML);
+
+  @override
+  Stream<ImplicitAnalysisEvent> get implicitAnalysisEvents =>
+      _implicitAnalysisEventsController.stream;
+
+  @override
+  bool get isDisposed => _disposed;
+
+  @override
+  List<Source> get launchableClientLibrarySources {
+    List<Source> sources = <Source>[];
+    for (Source source in _cache.sources) {
+      CacheEntry entry = _cache.get(source);
+      if (entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY &&
+          !source.isInSystemLibrary &&
+          isClientLibrary(source)) {
+        sources.add(source);
+      }
+    }
+    return sources;
+  }
+
+  @override
+  List<Source> get launchableServerLibrarySources {
+    List<Source> sources = <Source>[];
+    for (Source source in _cache.sources) {
+      CacheEntry entry = _cache.get(source);
+      if (source is Source &&
+          entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY &&
+          !source.isInSystemLibrary &&
+          isServerLibrary(source)) {
+        sources.add(source);
+      }
+    }
+    return sources;
+  }
+
+  @override
+  List<Source> get librarySources => _getSources(SourceKind.LIBRARY);
+
+  @override
+  Stream<SourcesChangedEvent> get onSourcesChanged =>
+      _onSourcesChangedController.stream;
+
+  /**
+   * Make _pendingFutureSources available to unit tests.
+   */
+  HashMap<AnalysisTarget,
+      List<PendingFuture>> get pendingFutureSources_forTesting =>
+      _pendingFutureTargets;
+
+  @override
+  List<Source> get prioritySources => _priorityOrder;
+
+  @override
+  List<AnalysisTarget> get priorityTargets => prioritySources;
+
+  @override
+  CachePartition get privateAnalysisCachePartition => _privatePartition;
+
+  @override
+  SourceFactory get sourceFactory => _sourceFactory;
+
+  @override
+  void set sourceFactory(SourceFactory factory) {
+    if (identical(_sourceFactory, factory)) {
+      return;
+    } else if (factory.context != null) {
+      throw new IllegalStateException(
+          "Source factories cannot be shared between contexts");
+    }
+    if (_sourceFactory != null) {
+      _sourceFactory.context = null;
+    }
+    factory.context = this;
+    _sourceFactory = factory;
+    _cache = createCacheFromSourceFactory(factory);
+    for (WorkManager workManager in workManagers) {
+      workManager.onSourceFactoryChanged();
+    }
+  }
+
+  @override
+  List<Source> get sources {
+    return _cache.sources.toList();
+  }
+
+  /**
+   * Return a list of the sources that would be processed by
+   * [performAnalysisTask]. This method duplicates, and must therefore be kept
+   * in sync with, [getNextAnalysisTask]. This method is intended to be used for
+   * testing purposes only.
+   */
+  List<Source> get sourcesNeedingProcessing {
+    HashSet<Source> sources = new HashSet<Source>();
+    bool hintsEnabled = _options.hint;
+    bool lintsEnabled = _options.lint;
+
+    MapIterator<AnalysisTarget, CacheEntry> iterator =
+        _privatePartition.iterator();
+    while (iterator.moveNext()) {
+      AnalysisTarget target = iterator.key;
+      if (target is Source) {
+        _getSourcesNeedingProcessing(
+            target, iterator.value, false, hintsEnabled, lintsEnabled, sources);
+      }
+    }
+    return new List<Source>.from(sources);
+  }
+
+  @override
+  AnalysisContextStatistics get statistics {
+    AnalysisContextStatisticsImpl statistics =
+        new AnalysisContextStatisticsImpl();
+    // TODO(brianwilkerson) Implement this.
+//    visitCacheItems(statistics._internalPutCacheItem);
+//    statistics.partitionData = _cache.partitionData;
+    return statistics;
+  }
+
+  List<Source> get test_priorityOrder => _priorityOrder;
+
+  @override
+  TypeProvider get typeProvider {
+    // Make sure a task didn't accidentally try to call back into the context
+    // to retrieve the type provider.
+    assert(!driver.isTaskRunning);
+
+    if (_typeProvider != null) {
+      return _typeProvider;
+    }
+    Source coreSource = sourceFactory.forUri(DartSdk.DART_CORE);
+    if (coreSource == null) {
+      throw new AnalysisException("Could not create a source for dart:core");
+    }
+    LibraryElement coreElement = computeLibraryElement(coreSource);
+    if (coreElement == null) {
+      throw new AnalysisException("Could not create an element for dart:core");
+    }
+    Source asyncSource = sourceFactory.forUri(DartSdk.DART_ASYNC);
+    if (asyncSource == null) {
+      throw new AnalysisException("Could not create a source for dart:async");
+    }
+    LibraryElement asyncElement = computeLibraryElement(asyncSource);
+    if (asyncElement == null) {
+      throw new AnalysisException("Could not create an element for dart:async");
+    }
+    _typeProvider = new TypeProviderImpl(coreElement, asyncElement);
+    return _typeProvider;
+  }
+
+  /**
+   * Sets the [TypeProvider] for this context.
+   */
+  void set typeProvider(TypeProvider typeProvider) {
+    _typeProvider = typeProvider;
+  }
+
+  @override
+  void addListener(AnalysisListener listener) {
+    if (!_listeners.contains(listener)) {
+      _listeners.add(listener);
+    }
+  }
+
+  @override
+  void applyAnalysisDelta(AnalysisDelta delta) {
+    ChangeSet changeSet = new ChangeSet();
+    delta.analysisLevels.forEach((Source source, AnalysisLevel level) {
+      if (level == AnalysisLevel.NONE) {
+        changeSet.removedSource(source);
+      } else {
+        changeSet.addedSource(source);
+      }
+    });
+    applyChanges(changeSet);
+  }
+
+  @override
+  void applyChanges(ChangeSet changeSet) {
+    if (changeSet.isEmpty) {
+      return;
+    }
+    //
+    // First, compute the list of sources that have been removed.
+    //
+    List<Source> removedSources =
+        new List<Source>.from(changeSet.removedSources);
+    for (SourceContainer container in changeSet.removedContainers) {
+      _addSourcesInContainer(removedSources, container);
+    }
+    //
+    // Then determine which cached results are no longer valid.
+    //
+    for (Source source in changeSet.addedSources) {
+      _sourceAvailable(source);
+    }
+    for (Source source in changeSet.changedSources) {
+      if (_contentCache.getContents(source) != null) {
+        // This source is overridden in the content cache, so the change will
+        // have no effect. Just ignore it to avoid wasting time doing
+        // re-analysis.
+        continue;
+      }
+      _sourceChanged(source);
+    }
+    changeSet.changedContents.forEach((Source key, String value) {
+      _contentsChanged(key, value, false);
+    });
+    changeSet.changedRanges
+        .forEach((Source source, ChangeSet_ContentChange change) {
+      _contentRangeChanged(source, change.contents, change.offset,
+          change.oldLength, change.newLength);
+    });
+    for (Source source in changeSet.deletedSources) {
+      _sourceDeleted(source);
+    }
+    for (Source source in removedSources) {
+      _sourceRemoved(source);
+    }
+    for (WorkManager workManager in workManagers) {
+      workManager.applyChange(
+          changeSet.addedSources, changeSet.changedSources, removedSources);
+    }
+    _onSourcesChangedController.add(new SourcesChangedEvent(changeSet));
+  }
+
+  @override
+  String computeDocumentationComment(Element element) {
+    if (element == null) {
+      return null;
+    }
+    Source source = element.source;
+    if (source == null) {
+      return null;
+    }
+    CompilationUnit unit = parseCompilationUnit(source);
+    if (unit == null) {
+      return null;
+    }
+    NodeLocator locator = new NodeLocator(element.nameOffset);
+    AstNode nameNode = locator.searchWithin(unit);
+    while (nameNode != null) {
+      if (nameNode is AnnotatedNode) {
+        Comment comment = nameNode.documentationComment;
+        if (comment == null) {
+          return null;
+        }
+        StringBuffer buffer = new StringBuffer();
+        List<Token> tokens = comment.tokens;
+        for (int i = 0; i < tokens.length; i++) {
+          if (i > 0) {
+            buffer.write("\n");
+          }
+          buffer.write(tokens[i].lexeme);
+        }
+        return buffer.toString();
+      }
+      nameNode = nameNode.parent;
+    }
+    return null;
+  }
+
+  @override
+  List<AnalysisError> computeErrors(Source source) {
+    String name = source.shortName;
+    if (AnalysisEngine.isDartFileName(name)) {
+      return computeResult(source, DART_ERRORS);
+    } else if (AnalysisEngine.isHtmlFileName(name)) {
+      return computeResult(source, HTML_ERRORS);
+    }
+    return AnalysisError.NO_ERRORS;
+  }
+
+  @override
+  List<Source> computeExportedLibraries(Source source) =>
+      computeResult(source, EXPORTED_LIBRARIES);
+
+  @override
+  @deprecated
+  HtmlElement computeHtmlElement(Source source) {
+    // TODO(brianwilkerson) Remove this method after switching to the new task
+    // model.
+    throw new UnimplementedError('Not supported in the new task model');
+  }
+
+  @override
+  List<Source> computeImportedLibraries(Source source) =>
+      computeResult(source, EXPLICITLY_IMPORTED_LIBRARIES);
+
+  @override
+  SourceKind computeKindOf(Source source) {
+    String name = source.shortName;
+    if (AnalysisEngine.isDartFileName(name)) {
+      return computeResult(source, SOURCE_KIND);
+    } else if (AnalysisEngine.isHtmlFileName(name)) {
+      return SourceKind.HTML;
+    }
+    return SourceKind.UNKNOWN;
+  }
+
+  @override
+  LibraryElement computeLibraryElement(Source source) {
+    //_computeResult(source, HtmlEntry.ELEMENT);
+    return computeResult(source, LIBRARY_ELEMENT);
+  }
+
+  @override
+  LineInfo computeLineInfo(Source source) => computeResult(source, LINE_INFO);
+
+  @override
+  @deprecated
+  CompilationUnit computeResolvableCompilationUnit(Source source) {
+    return null;
+  }
+
+  @override
+  CancelableFuture<CompilationUnit> computeResolvedCompilationUnitAsync(
+      Source unitSource, Source librarySource) {
+    if (!AnalysisEngine.isDartFileName(unitSource.shortName) ||
+        !AnalysisEngine.isDartFileName(librarySource.shortName)) {
+      return new CancelableFuture.error(new AnalysisNotScheduledError());
+    }
+    var unitTarget = new LibrarySpecificUnit(librarySource, unitSource);
+    return new _AnalysisFutureHelper<CompilationUnit>(this)
+        .computeAsync(unitTarget, (CacheEntry entry) {
+      CacheState state = entry.getState(RESOLVED_UNIT);
+      if (state == CacheState.ERROR) {
+        throw entry.exception;
+      } else if (state == CacheState.INVALID) {
+        return null;
+      }
+      return entry.getValue(RESOLVED_UNIT);
+    }, () {
+      dartWorkManager.addPriorityResult(unitTarget, RESOLVED_UNIT);
+    });
+  }
+
+  @override
+  Object /*V*/ computeResult(
+      AnalysisTarget target, ResultDescriptor /*<V>*/ descriptor) {
+    CacheEntry entry = getCacheEntry(target);
+    CacheState state = entry.getState(descriptor);
+    if (state == CacheState.FLUSHED || state == CacheState.INVALID) {
+      driver.computeResult(target, descriptor);
+    }
+    state = entry.getState(descriptor);
+    if (state == CacheState.ERROR) {
+      throw new AnalysisException(
+          'Cannot compute $descriptor for $target', entry.exception);
+    }
+    return entry.getValue(descriptor);
+  }
+
+  /**
+   * Create an analysis cache based on the given source [factory].
+   */
+  AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
+    if (factory == null) {
+      return new AnalysisCache(<CachePartition>[_privatePartition]);
+    }
+    DartSdk sdk = factory.dartSdk;
+    if (sdk == null) {
+      return new AnalysisCache(<CachePartition>[_privatePartition]);
+    }
+    return new AnalysisCache(<CachePartition>[
+      AnalysisEngine.instance.partitionManager_new.forSdk(sdk),
+      _privatePartition
+    ]);
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    for (List<PendingFuture> pendingFutures in _pendingFutureTargets.values) {
+      for (PendingFuture pendingFuture in pendingFutures) {
+        pendingFuture.forciblyComplete();
+      }
+    }
+    _pendingFutureTargets.clear();
+    _privatePartition.dispose();
+  }
+
+  @override
+  List<CompilationUnit> ensureResolvedDartUnits(Source unitSource) {
+    // Check every library.
+    List<CompilationUnit> units = <CompilationUnit>[];
+    List<Source> containingLibraries = getLibrariesContaining(unitSource);
+    for (Source librarySource in containingLibraries) {
+      LibrarySpecificUnit target =
+          new LibrarySpecificUnit(librarySource, unitSource);
+      CompilationUnit unit = getResult(target, RESOLVED_UNIT);
+      if (unit == null) {
+        units = null;
+        break;
+      }
+      units.add(unit);
+    }
+    // If we have results, then we're done.
+    if (units != null) {
+      return units;
+    }
+    // Schedule recomputing RESOLVED_UNIT results.
+    for (Source librarySource in containingLibraries) {
+      LibrarySpecificUnit target =
+          new LibrarySpecificUnit(librarySource, unitSource);
+      if (_cache.getState(target, RESOLVED_UNIT) == CacheState.FLUSHED) {
+        dartWorkManager.addPriorityResult(target, RESOLVED_UNIT);
+      }
+    }
+    return null;
+  }
+
+  @override
+  bool exists(Source source) {
+    if (source == null) {
+      return false;
+    }
+    if (_contentCache.getContents(source) != null) {
+      return true;
+    }
+    return source.exists();
+  }
+
+  @override
+  CacheEntry getCacheEntry(AnalysisTarget target) {
+    CacheEntry entry = _cache.get(target);
+    if (entry == null) {
+      entry = new CacheEntry(target);
+      if (target is Source) {
+        entry.modificationTime = getModificationStamp(target);
+      }
+      _cache.put(entry);
+      if (target is Source) {
+        _implicitAnalysisEventsController
+            .add(new ImplicitAnalysisEvent(target, true));
+      }
+    }
+    return entry;
+  }
+
+  @override
+  CompilationUnitElement getCompilationUnitElement(
+      Source unitSource, Source librarySource) {
+    AnalysisTarget target = new LibrarySpecificUnit(librarySource, unitSource);
+    return getResult(target, COMPILATION_UNIT_ELEMENT);
+  }
+
+  @override
+  TimestampedData<String> getContents(Source source) {
+    String contents = _contentCache.getContents(source);
+    if (contents != null) {
+      return new TimestampedData<String>(
+          _contentCache.getModificationStamp(source), contents);
+    }
+    return source.contents;
+  }
+
+  @override
+  InternalAnalysisContext getContextFor(Source source) {
+    InternalAnalysisContext context = _cache.getContextFor(source);
+    return context == null ? this : context;
+  }
+
+  @override
+  Element getElement(ElementLocation location) {
+    // TODO(brianwilkerson) This should not be a "get" method.
+    try {
+      List<String> components = location.components;
+      Source source = _computeSourceFromEncoding(components[0]);
+      String sourceName = source.shortName;
+      if (AnalysisEngine.isDartFileName(sourceName)) {
+        ElementImpl element = computeLibraryElement(source) as ElementImpl;
+        for (int i = 1; i < components.length; i++) {
+          if (element == null) {
+            return null;
+          }
+          element = element.getChild(components[i]);
+        }
+        return element;
+      }
+    } catch (exception) {
+      // If the location cannot be decoded for some reason then the underlying
+      // cause should have been logged already and we can fall though to return
+      // null.
+    }
+    return null;
+  }
+
+  @override
+  AnalysisErrorInfo getErrors(Source source) {
+    List<AnalysisError> allErrors = <AnalysisError>[];
+    for (WorkManager workManager in workManagers) {
+      List<AnalysisError> errors = workManager.getErrors(source);
+      allErrors.addAll(errors);
+    }
+    LineInfo lineInfo = getLineInfo(source);
+    return new AnalysisErrorInfoImpl(allErrors, lineInfo);
+  }
+
+  @override
+  @deprecated
+  HtmlElement getHtmlElement(Source source) {
+    // TODO(brianwilkerson) Remove this method after switching to the new task
+    // model.
+    throw new UnimplementedError('Not supported in the new task model');
+  }
+
+  @override
+  List<Source> getHtmlFilesReferencing(Source source) {
+    if (!AnalysisEngine.isDartFileName(source.shortName)) {
+      return Source.EMPTY_LIST;
+    }
+    List<Source> htmlSources = <Source>[];
+    List<Source> librarySources = getLibrariesContaining(source);
+    for (Source source in _cache.sources) {
+      if (AnalysisEngine.isHtmlFileName(source.shortName)) {
+        List<Source> referencedLibraries =
+            getResult(source, REFERENCED_LIBRARIES);
+        if (_containsAny(referencedLibraries, librarySources)) {
+          htmlSources.add(source);
+        }
+      }
+    }
+    if (htmlSources.isEmpty) {
+      return Source.EMPTY_LIST;
+    }
+    return htmlSources;
+  }
+
+  @override
+  SourceKind getKindOf(Source source) {
+    String name = source.shortName;
+    if (AnalysisEngine.isDartFileName(name)) {
+      return getResult(source, SOURCE_KIND);
+    } else if (AnalysisEngine.isHtmlFileName(name)) {
+      return SourceKind.HTML;
+    }
+    return SourceKind.UNKNOWN;
+  }
+
+  @override
+  List<Source> getLibrariesContaining(Source source) {
+    SourceKind kind = getKindOf(source);
+    if (kind == SourceKind.LIBRARY) {
+      return <Source>[source];
+    }
+    return dartWorkManager.getLibrariesContainingPart(source);
+  }
+
+  @override
+  List<Source> getLibrariesDependingOn(Source librarySource) {
+    List<Source> dependentLibraries = <Source>[];
+    for (Source source in _cache.sources) {
+      CacheEntry entry = _cache.get(source);
+      if (entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY) {
+        if (_contains(entry.getValue(EXPORTED_LIBRARIES), librarySource)) {
+          dependentLibraries.add(source);
+        }
+        if (_contains(entry.getValue(IMPORTED_LIBRARIES), librarySource)) {
+          dependentLibraries.add(source);
+        }
+      }
+    }
+    if (dependentLibraries.isEmpty) {
+      return Source.EMPTY_LIST;
+    }
+    return dependentLibraries;
+  }
+
+  @override
+  List<Source> getLibrariesReferencedFromHtml(Source htmlSource) {
+    CacheEntry entry = _cache.get(htmlSource);
+    if (entry != null) {
+      return entry.getValue(REFERENCED_LIBRARIES);
+    }
+    return Source.EMPTY_LIST;
+  }
+
+  @override
+  LibraryElement getLibraryElement(Source source) =>
+      getResult(source, LIBRARY_ELEMENT);
+
+  @override
+  LineInfo getLineInfo(Source source) => getResult(source, LINE_INFO);
+
+  @override
+  int getModificationStamp(Source source) {
+    int stamp = _contentCache.getModificationStamp(source);
+    if (stamp != null) {
+      return stamp;
+    }
+    return source.modificationStamp;
+  }
+
+  @override
+  ChangeNoticeImpl getNotice(Source source) {
+    ChangeNoticeImpl notice = _pendingNotices[source];
+    if (notice == null) {
+      notice = new ChangeNoticeImpl(source);
+      _pendingNotices[source] = notice;
+    }
+    return notice;
+  }
+
+  @override
+  Namespace getPublicNamespace(LibraryElement library) {
+    // TODO(brianwilkerson) Rename this to not start with 'get'.
+    // Note that this is not part of the API of the interface.
+    // TODO(brianwilkerson) The public namespace used to be cached, but no
+    // longer is. Konstantin adds:
+    // The only client of this method is NamespaceBuilder._createExportMapping(),
+    // and it is not used with tasks - instead we compute export namespace once
+    // using BuildExportNamespaceTask and reuse in scopes.
+    NamespaceBuilder builder = new NamespaceBuilder();
+    return builder.createPublicNamespaceForLibrary(library);
+  }
+
+  @override
+  CompilationUnit getResolvedCompilationUnit(
+      Source unitSource, LibraryElement library) {
+    if (library == null ||
+        !AnalysisEngine.isDartFileName(unitSource.shortName)) {
+      return null;
+    }
+    return getResolvedCompilationUnit2(unitSource, library.source);
+  }
+
+  @override
+  CompilationUnit getResolvedCompilationUnit2(
+      Source unitSource, Source librarySource) {
+    if (!AnalysisEngine.isDartFileName(unitSource.shortName) ||
+        !AnalysisEngine.isDartFileName(librarySource.shortName)) {
+      return null;
+    }
+    return getResult(
+        new LibrarySpecificUnit(librarySource, unitSource), RESOLVED_UNIT);
+  }
+
+  @override
+  @deprecated
+  ht.HtmlUnit getResolvedHtmlUnit(Source htmlSource) {
+    // TODO(brianwilkerson) Remove this method after switching to the new task
+    // model.
+    throw new UnimplementedError('Not supported in the new task model');
+  }
+
+  @override
+  Object getResult(AnalysisTarget target, ResultDescriptor result) {
+    return _cache.getValue(target, result);
+  }
+
+  @override
+  List<Source> getSourcesWithFullName(String path) {
+    return analysisCache.getSourcesWithFullName(path);
+  }
+
+  @override
+  bool handleContentsChanged(
+      Source source, String originalContents, String newContents, bool notify) {
+    CacheEntry entry = _cache.get(source);
+    if (entry == null) {
+      return false;
+    }
+    bool changed = newContents != originalContents;
+    if (newContents != null) {
+      if (changed) {
+        if (!analysisOptions.incremental ||
+            !_tryPoorMansIncrementalResolution(source, newContents)) {
+          _sourceChanged(source);
+        }
+        entry.modificationTime = _contentCache.getModificationStamp(source);
+        entry.setValue(CONTENT, newContents, TargetedResult.EMPTY_LIST);
+      } else {
+        entry.modificationTime = _contentCache.getModificationStamp(source);
+      }
+    } else if (originalContents != null) {
+      // We are removing the overlay for the file, check if the file's
+      // contents is the same as it was in the overlay.
+      try {
+        TimestampedData<String> fileContents = getContents(source);
+        newContents = fileContents.data;
+        entry.modificationTime = fileContents.modificationTime;
+        if (newContents == originalContents) {
+          entry.setValue(CONTENT, newContents, TargetedResult.EMPTY_LIST);
+          changed = false;
+        }
+      } catch (e) {}
+      // If not the same content (e.g. the file is being closed without save),
+      // then force analysis.
+      if (changed) {
+        if (!analysisOptions.incremental ||
+            !_tryPoorMansIncrementalResolution(source, newContents)) {
+          _sourceChanged(source);
+        }
+      }
+    }
+    if (notify && changed) {
+      _onSourcesChangedController
+          .add(new SourcesChangedEvent.changedContent(source, newContents));
+    }
+    return changed;
+  }
+
+  @override
+  void invalidateLibraryHints(Source librarySource) {
+    List<Source> sources = getResult(librarySource, UNITS);
+    if (sources != null) {
+      for (Source source in sources) {
+        getCacheEntry(source).setState(HINTS, CacheState.INVALID);
+      }
+    }
+  }
+
+  @override
+  bool isClientLibrary(Source librarySource) {
+    CacheEntry entry = _cache.get(librarySource);
+    return entry.getValue(IS_CLIENT) && entry.getValue(IS_LAUNCHABLE);
+  }
+
+  @override
+  bool isServerLibrary(Source librarySource) {
+    CacheEntry entry = _cache.get(librarySource);
+    return !entry.getValue(IS_CLIENT) && entry.getValue(IS_LAUNCHABLE);
+  }
+
+  @override
+  Stream<ComputedResult> onResultComputed(ResultDescriptor descriptor) {
+    return driver.onResultComputed(descriptor);
+  }
+
+  @override
+  CompilationUnit parseCompilationUnit(Source source) {
+    if (!AnalysisEngine.isDartFileName(source.shortName)) {
+      return null;
+    }
+    try {
+      getContents(source);
+    } catch (exception, stackTrace) {
+      throw new AnalysisException('Could not get contents of $source',
+          new CaughtException(exception, stackTrace));
+    }
+    return computeResult(source, PARSED_UNIT);
+  }
+
+  @override
+  Document parseHtmlDocument(Source source) {
+    if (!AnalysisEngine.isHtmlFileName(source.shortName)) {
+      return null;
+    }
+    return computeResult(source, HTML_DOCUMENT);
+  }
+
+  @override
+  @deprecated // use parseHtmlDocument(source)
+  ht.HtmlUnit parseHtmlUnit(Source source) {
+    // TODO(brianwilkerson) Remove this method after switching to the new task
+    // model.
+    throw new UnimplementedError('Not supported in the new task model');
+  }
+
+  @override
+  AnalysisResult performAnalysisTask() {
+    return PerformanceStatistics.performAnaysis.makeCurrentWhile(() {
+      _evaluatePendingFutures();
+      bool done = !driver.performAnalysisTask();
+      List<ChangeNotice> notices = _getChangeNotices(done);
+      if (notices != null) {
+        int noticeCount = notices.length;
+        for (int i = 0; i < noticeCount; i++) {
+          ChangeNotice notice = notices[i];
+          _notifyErrors(notice.source, notice.errors, notice.lineInfo);
+        }
+      }
+      return new AnalysisResult(notices, -1, '', -1);
+    });
+  }
+
+  @override
+  void recordLibraryElements(Map<Source, LibraryElement> elementMap) {
+    elementMap.forEach((Source librarySource, LibraryElement library) {
+      //
+      // Cache the element in the library's info.
+      //
+      CacheEntry entry = getCacheEntry(librarySource);
+      setValue(ResultDescriptor result, value) {
+        entry.setValue(result, value, TargetedResult.EMPTY_LIST);
+      }
+      setValue(BUILD_DIRECTIVES_ERRORS, AnalysisError.NO_ERRORS);
+      setValue(BUILD_LIBRARY_ERRORS, AnalysisError.NO_ERRORS);
+      // CLASS_ELEMENTS
+      setValue(COMPILATION_UNIT_ELEMENT, library.definingCompilationUnit);
+      // CONSTRUCTORS
+      // CONSTRUCTORS_ERRORS
+      entry.setState(CONTENT, CacheState.FLUSHED);
+      setValue(EXPORTED_LIBRARIES, Source.EMPTY_LIST);
+      // EXPORT_SOURCE_CLOSURE
+      setValue(IMPORTED_LIBRARIES, Source.EMPTY_LIST);
+      // IMPORT_SOURCE_CLOSURE
+      setValue(INCLUDED_PARTS, Source.EMPTY_LIST);
+      setValue(IS_CLIENT, true);
+      setValue(IS_LAUNCHABLE, false);
+      setValue(LIBRARY_ELEMENT, library);
+      setValue(LIBRARY_ELEMENT1, library);
+      setValue(LIBRARY_ELEMENT2, library);
+      setValue(LIBRARY_ELEMENT3, library);
+      setValue(LIBRARY_ELEMENT4, library);
+      setValue(LIBRARY_ELEMENT5, library);
+      setValue(LINE_INFO, new LineInfo(<int>[0]));
+      setValue(PARSE_ERRORS, AnalysisError.NO_ERRORS);
+      entry.setState(PARSED_UNIT, CacheState.FLUSHED);
+      entry.setState(RESOLVE_TYPE_NAMES_ERRORS, CacheState.FLUSHED);
+      setValue(SCAN_ERRORS, AnalysisError.NO_ERRORS);
+      setValue(SOURCE_KIND, SourceKind.LIBRARY);
+      entry.setState(TOKEN_STREAM, CacheState.FLUSHED);
+      setValue(UNITS, <Source>[librarySource]);
+
+      LibrarySpecificUnit unit =
+          new LibrarySpecificUnit(librarySource, librarySource);
+      entry = getCacheEntry(unit);
+      setValue(HINTS, AnalysisError.NO_ERRORS);
+      // dartEntry.setValue(LINTS, AnalysisError.NO_ERRORS);
+      entry.setState(RESOLVE_REFERENCES_ERRORS, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT1, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT2, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT3, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT4, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT5, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT6, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT7, CacheState.FLUSHED);
+      entry.setState(RESOLVED_UNIT8, CacheState.FLUSHED);
+      // USED_IMPORTED_ELEMENTS
+      // USED_LOCAL_ELEMENTS
+      setValue(VERIFY_ERRORS, AnalysisError.NO_ERRORS);
+    });
+
+    CacheEntry entry = getCacheEntry(AnalysisContextTarget.request);
+    entry.setValue(TYPE_PROVIDER, typeProvider, TargetedResult.EMPTY_LIST);
+  }
+
+  @override
+  void removeListener(AnalysisListener listener) {
+    _listeners.remove(listener);
+  }
+
+  @override
+  CompilationUnit resolveCompilationUnit(
+      Source unitSource, LibraryElement library) {
+    if (library == null) {
+      return null;
+    }
+    return resolveCompilationUnit2(unitSource, library.source);
+  }
+
+  @override
+  CompilationUnit resolveCompilationUnit2(
+      Source unitSource, Source librarySource) {
+    if (!AnalysisEngine.isDartFileName(unitSource.shortName) ||
+        !AnalysisEngine.isDartFileName(librarySource.shortName)) {
+      return null;
+    }
+    return computeResult(
+        new LibrarySpecificUnit(librarySource, unitSource), RESOLVED_UNIT);
+  }
+
+  @override
+  @deprecated
+  ht.HtmlUnit resolveHtmlUnit(Source htmlSource) {
+    // TODO(brianwilkerson) Remove this method after switching to the new task
+    // model.
+    throw new UnimplementedError('Not supported in the new task model');
+  }
+
+  @override
+  void setChangedContents(Source source, String contents, int offset,
+      int oldLength, int newLength) {
+    if (_contentRangeChanged(source, contents, offset, oldLength, newLength)) {
+      _onSourcesChangedController.add(new SourcesChangedEvent.changedRange(
+          source, contents, offset, oldLength, newLength));
+    }
+  }
+
+  @override
+  void setContents(Source source, String contents) {
+    _contentsChanged(source, contents, true);
+  }
+
+  @override
+  bool shouldErrorsBeAnalyzed(Source source, Object entry) {
+    CacheEntry entry = analysisCache.get(source);
+    if (source.isInSystemLibrary) {
+      return _options.generateSdkErrors;
+    } else if (!entry.explicitlyAdded) {
+      return _options.generateImplicitErrors;
+    } else {
+      return true;
+    }
+  }
+
+  @override
+  void test_flushAstStructures(Source source) {
+    CacheEntry entry = getCacheEntry(source);
+    entry.setState(PARSED_UNIT, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT1, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT2, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT3, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT4, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT5, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT6, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT5, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT8, CacheState.FLUSHED);
+    entry.setState(RESOLVED_UNIT, CacheState.FLUSHED);
+  }
+
+  @override
+  bool validateCacheConsistency() {
+    int consistencyCheckStart = JavaSystem.nanoTime();
+    HashSet<Source> changedSources = new HashSet<Source>();
+    HashSet<Source> missingSources = new HashSet<Source>();
+    for (Source source in _cache.sources) {
+      CacheEntry entry = _cache.get(source);
+      int sourceTime = getModificationStamp(source);
+      if (sourceTime != entry.modificationTime) {
+        changedSources.add(source);
+      }
+      if (entry.exception != null) {
+        if (!exists(source)) {
+          missingSources.add(source);
+        }
+      }
+    }
+    for (Source source in changedSources) {
+      _sourceChanged(source);
+    }
+    int removalCount = 0;
+    for (Source source in missingSources) {
+      if (getLibrariesContaining(source).isEmpty &&
+          getLibrariesDependingOn(source).isEmpty) {
+        _removeFromCache(source);
+        removalCount++;
+      }
+    }
+    int consistencyCheckEnd = JavaSystem.nanoTime();
+    if (changedSources.length > 0 || missingSources.length > 0) {
+      StringBuffer buffer = new StringBuffer();
+      buffer.write("Consistency check took ");
+      buffer.write((consistencyCheckEnd - consistencyCheckStart) / 1000000.0);
+      buffer.writeln(" ms and found");
+      buffer.write("  ");
+      buffer.write(changedSources.length);
+      buffer.writeln(" inconsistent entries");
+      buffer.write("  ");
+      buffer.write(missingSources.length);
+      buffer.write(" missing sources (");
+      buffer.write(removalCount);
+      buffer.writeln(" removed");
+      for (Source source in missingSources) {
+        buffer.write("    ");
+        buffer.writeln(source.fullName);
+      }
+      _logInformation(buffer.toString());
+    }
+    return changedSources.length > 0;
+  }
+
+  @deprecated
+  @override
+  void visitCacheItems(void callback(Source source, SourceEntry dartEntry,
+      DataDescriptor rowDesc, CacheState state)) {
+    // TODO(brianwilkerson) Figure out where this is used and either remove it
+    // or adjust the call sites to use CacheEntry's.
+//    bool hintsEnabled = _options.hint;
+//    bool lintsEnabled = _options.lint;
+//    MapIterator<AnalysisTarget, cache.CacheEntry> iterator = _cache.iterator();
+//    while (iterator.moveNext()) {
+//      Source source = iterator.key;
+//      cache.CacheEntry entry = iterator.value;
+//      for (DataDescriptor descriptor in entry.descriptors) {
+//        if (descriptor == DartEntry.SOURCE_KIND) {
+//          // The source kind is always valid, so the state isn't interesting.
+//          continue;
+//        } else if (descriptor == DartEntry.CONTAINING_LIBRARIES) {
+//          // The list of containing libraries is always valid, so the state
+//          // isn't interesting.
+//          continue;
+//        } else if (descriptor == DartEntry.PUBLIC_NAMESPACE) {
+//          // The public namespace isn't computed by performAnalysisTask()
+//          // and therefore isn't interesting.
+//          continue;
+//        } else if (descriptor == HtmlEntry.HINTS) {
+//          // We are not currently recording any hints related to HTML.
+//          continue;
+//        }
+//        callback(
+//            source, entry, descriptor, entry.getState(descriptor));
+//      }
+//      if (entry is DartEntry) {
+//        // get library-specific values
+//        List<Source> librarySources = getLibrariesContaining(source);
+//        for (Source librarySource in librarySources) {
+//          for (DataDescriptor descriptor in entry.libraryDescriptors) {
+//            if (descriptor == DartEntry.BUILT_ELEMENT ||
+//                descriptor == DartEntry.BUILT_UNIT) {
+//              // These values are not currently being computed, so their state
+//              // is not interesting.
+//              continue;
+//            } else if (!entry.explicitlyAdded &&
+//                !_generateImplicitErrors &&
+//                (descriptor == DartEntry.VERIFICATION_ERRORS ||
+//                    descriptor == DartEntry.HINTS ||
+//                    descriptor == DartEntry.LINTS)) {
+//              continue;
+//            } else if (source.isInSystemLibrary &&
+//                !_generateSdkErrors &&
+//                (descriptor == DartEntry.VERIFICATION_ERRORS ||
+//                    descriptor == DartEntry.HINTS ||
+//                    descriptor == DartEntry.LINTS)) {
+//              continue;
+//            } else if (!hintsEnabled && descriptor == DartEntry.HINTS) {
+//              continue;
+//            } else if (!lintsEnabled && descriptor == DartEntry.LINTS) {
+//              continue;
+//            }
+//            callback(librarySource, entry, descriptor,
+//                entry.getStateInLibrary(descriptor, librarySource));
+//          }
+//        }
+//      }
+//    }
+  }
+
+  @override
+  void visitContentCache(ContentCacheVisitor visitor) {
+    _contentCache.accept(visitor);
+  }
+
+  /**
+   * Add all of the sources contained in the given source [container] to the
+   * given list of [sources].
+   */
+  void _addSourcesInContainer(List<Source> sources, SourceContainer container) {
+    for (Source source in _cache.sources) {
+      if (container.contains(source)) {
+        sources.add(source);
+      }
+    }
+  }
+
+  /**
+   * Remove the given [pendingFuture] from [_pendingFutureTargets], since the
+   * client has indicated its computation is not needed anymore.
+   */
+  void _cancelFuture(PendingFuture pendingFuture) {
+    List<PendingFuture> pendingFutures =
+        _pendingFutureTargets[pendingFuture.target];
+    if (pendingFutures != null) {
+      pendingFutures.remove(pendingFuture);
+      if (pendingFutures.isEmpty) {
+        _pendingFutureTargets.remove(pendingFuture.target);
+      }
+    }
+  }
+
+  /**
+   * Given the encoded form of a source ([encoding]), use the source factory to
+   * reconstitute the original source.
+   */
+  Source _computeSourceFromEncoding(String encoding) =>
+      _sourceFactory.fromEncoding(encoding);
+
+  /**
+   * Return `true` if the given list of [sources] contains the given
+   * [targetSource].
+   */
+  bool _contains(List<Source> sources, Source targetSource) {
+    for (Source source in sources) {
+      if (source == targetSource) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Return `true` if the given list of [sources] contains any of the given
+   * [targetSources].
+   */
+  bool _containsAny(List<Source> sources, List<Source> targetSources) {
+    for (Source targetSource in targetSources) {
+      if (_contains(sources, targetSource)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Set the contents of the given [source] to the given [contents] and mark the
+   * source as having changed. The additional [offset], [oldLength] and
+   * [newLength] information is used by the context to determine what reanalysis
+   * is necessary. The method [setChangedContents] triggers a source changed
+   * event where as this method does not.
+   */
+  bool _contentRangeChanged(Source source, String contents, int offset,
+      int oldLength, int newLength) {
+    bool changed = false;
+    String originalContents = _contentCache.setContents(source, contents);
+    if (contents != null) {
+      if (contents != originalContents) {
+        _sourceChanged(source);
+        changed = true;
+        CacheEntry entry = _cache.get(source);
+        if (entry != null) {
+          entry.modificationTime = _contentCache.getModificationStamp(source);
+          entry.setValue(CONTENT, contents, TargetedResult.EMPTY_LIST);
+        }
+      }
+    } else if (originalContents != null) {
+      _sourceChanged(source);
+      changed = true;
+    }
+    return changed;
+  }
+
+  /**
+   * Set the contents of the given [source] to the given [contents] and mark the
+   * source as having changed. This has the effect of overriding the default
+   * contents of the source. If the contents are `null` the override is removed
+   * so that the default contents will be returned. If [notify] is true, a
+   * source changed event is triggered.
+   */
+  void _contentsChanged(Source source, String contents, bool notify) {
+    String originalContents = _contentCache.setContents(source, contents);
+    handleContentsChanged(source, originalContents, contents, notify);
+  }
+
+  /**
+   * Create a cache entry for the given [source]. The source was explicitly
+   * added to this context if [explicitlyAdded] is `true`. Return the cache
+   * entry that was created.
+   */
+  CacheEntry _createCacheEntry(Source source, bool explicitlyAdded) {
+    CacheEntry entry = new CacheEntry(source);
+    entry.modificationTime = getModificationStamp(source);
+    entry.explicitlyAdded = explicitlyAdded;
+    _cache.put(entry);
+    if (!explicitlyAdded) {
+      _implicitAnalysisEventsController
+          .add(new ImplicitAnalysisEvent(source, true));
+    }
+    return entry;
+  }
+
+  /**
+   * Return a list containing all of the cache entries for targets associated
+   * with the given [source].
+   */
+  List<CacheEntry> _entriesFor(Source source) {
+    List<CacheEntry> entries = <CacheEntry>[];
+    MapIterator<AnalysisTarget, CacheEntry> iterator = _cache.iterator();
+    while (iterator.moveNext()) {
+      if (iterator.key.source == source) {
+        entries.add(iterator.value);
+      }
+    }
+    return entries;
+  }
+
+  void _evaluatePendingFutures() {
+    for (AnalysisTarget target in _pendingFutureTargets.keys) {
+      CacheEntry cacheEntry = _cache.get(target);
+      List<PendingFuture> pendingFutures = _pendingFutureTargets[target];
+      for (int i = 0; i < pendingFutures.length;) {
+        if (pendingFutures[i].evaluate(cacheEntry)) {
+          pendingFutures.removeAt(i);
+        } else {
+          i++;
+        }
+      }
+    }
+  }
+
+  /**
+   * Return a list containing all of the change notices that are waiting to be
+   * returned. If there are no notices, then return either `null` or an empty
+   * list, depending on the value of [nullIfEmpty].
+   */
+  List<ChangeNotice> _getChangeNotices(bool nullIfEmpty) {
+    if (_pendingNotices.isEmpty) {
+      if (nullIfEmpty) {
+        return null;
+      }
+      return ChangeNoticeImpl.EMPTY_LIST;
+    }
+    List<ChangeNotice> notices = new List.from(_pendingNotices.values);
+    _pendingNotices.clear();
+    return notices;
+  }
+
+  /**
+   * Return a list containing all of the sources known to this context that have
+   * the given [kind].
+   */
+  List<Source> _getSources(SourceKind kind) {
+    List<Source> sources = <Source>[];
+    if (kind == SourceKind.LIBRARY || kind == SourceKind.PART) {
+      for (Source source in _cache.sources) {
+        CacheEntry entry = _cache.get(source);
+        if (entry.getValue(SOURCE_KIND) == kind) {
+          sources.add(source);
+        }
+      }
+    } else if (kind == SourceKind.HTML) {
+      for (Source source in _cache.sources) {
+        if (AnalysisEngine.isHtmlFileName(source.shortName)) {
+          sources.add(source);
+        }
+      }
+    }
+    if (sources.isEmpty) {
+      return Source.EMPTY_LIST;
+    }
+    return sources;
+  }
+
+  /**
+   * Look at the given [source] to see whether a task needs to be performed
+   * related to it. If so, add the source to the set of sources that need to be
+   * processed. This method is intended to be used for testing purposes only.
+   */
+  void _getSourcesNeedingProcessing(
+      Source source,
+      CacheEntry entry,
+      bool isPriority,
+      bool hintsEnabled,
+      bool lintsEnabled,
+      HashSet<Source> sources) {
+    CacheState state = entry.getState(CONTENT);
+    if (state == CacheState.INVALID ||
+        (isPriority && state == CacheState.FLUSHED)) {
+      sources.add(source);
+      return;
+    } else if (state == CacheState.ERROR) {
+      return;
+    }
+    state = entry.getState(SOURCE_KIND);
+    if (state == CacheState.INVALID ||
+        (isPriority && state == CacheState.FLUSHED)) {
+      sources.add(source);
+      return;
+    } else if (state == CacheState.ERROR) {
+      return;
+    }
+    SourceKind kind = entry.getValue(SOURCE_KIND);
+    if (kind == SourceKind.LIBRARY || kind == SourceKind.PART) {
+      state = entry.getState(SCAN_ERRORS);
+      if (state == CacheState.INVALID ||
+          (isPriority && state == CacheState.FLUSHED)) {
+        sources.add(source);
+        return;
+      } else if (state == CacheState.ERROR) {
+        return;
+      }
+      state = entry.getState(PARSE_ERRORS);
+      if (state == CacheState.INVALID ||
+          (isPriority && state == CacheState.FLUSHED)) {
+        sources.add(source);
+        return;
+      } else if (state == CacheState.ERROR) {
+        return;
+      }
+//      if (isPriority) {
+//        if (!entry.hasResolvableCompilationUnit) {
+//          sources.add(source);
+//          return;
+//        }
+//      }
+      for (Source librarySource in getLibrariesContaining(source)) {
+        CacheEntry libraryEntry = _cache.get(librarySource);
+        state = libraryEntry.getState(LIBRARY_ELEMENT);
+        if (state == CacheState.INVALID ||
+            (isPriority && state == CacheState.FLUSHED)) {
+          sources.add(source);
+          return;
+        } else if (state == CacheState.ERROR) {
+          return;
+        }
+        CacheEntry unitEntry =
+            _cache.get(new LibrarySpecificUnit(librarySource, source));
+        state = unitEntry.getState(RESOLVED_UNIT);
+        if (state == CacheState.INVALID ||
+            (isPriority && state == CacheState.FLUSHED)) {
+          sources.add(source);
+          return;
+        } else if (state == CacheState.ERROR) {
+          return;
+        }
+        if (shouldErrorsBeAnalyzed(source, unitEntry)) {
+          state = unitEntry.getState(VERIFY_ERRORS);
+          if (state == CacheState.INVALID ||
+              (isPriority && state == CacheState.FLUSHED)) {
+            sources.add(source);
+            return;
+          } else if (state == CacheState.ERROR) {
+            return;
+          }
+          if (hintsEnabled) {
+            state = unitEntry.getState(HINTS);
+            if (state == CacheState.INVALID ||
+                (isPriority && state == CacheState.FLUSHED)) {
+              sources.add(source);
+              return;
+            } else if (state == CacheState.ERROR) {
+              return;
+            }
+          }
+//          if (lintsEnabled) {
+//            state = unitEntry.getState(LINTS);
+//            if (state == CacheState.INVALID ||
+//                (isPriority && state == CacheState.FLUSHED)) {
+//              sources.add(source);
+//              return;
+//            } else if (state == CacheState.ERROR) {
+//              return;
+//            }
+//          }
+        }
+      }
+//    } else if (kind == SourceKind.HTML) {
+//      CacheState parsedUnitState = entry.getState(HtmlEntry.PARSED_UNIT);
+//      if (parsedUnitState == CacheState.INVALID ||
+//          (isPriority && parsedUnitState == CacheState.FLUSHED)) {
+//        sources.add(source);
+//        return;
+//      }
+//      CacheState resolvedUnitState =
+//          entry.getState(HtmlEntry.RESOLVED_UNIT);
+//      if (resolvedUnitState == CacheState.INVALID ||
+//          (isPriority && resolvedUnitState == CacheState.FLUSHED)) {
+//        sources.add(source);
+//        return;
+//      }
+    }
+  }
+
+  /**
+   * Log the given debugging [message].
+   */
+  void _logInformation(String message) {
+    AnalysisEngine.instance.logger.logInformation(message);
+  }
+
+  /**
+   * Notify all of the analysis listeners that the errors associated with the
+   * given [source] has been updated to the given [errors].
+   */
+  void _notifyErrors(
+      Source source, List<AnalysisError> errors, LineInfo lineInfo) {
+    int count = _listeners.length;
+    for (int i = 0; i < count; i++) {
+      _listeners[i].computedErrors(this, source, errors, lineInfo);
+    }
+  }
+
+  void _removeFromCache(Source source) {
+    CacheEntry entry = _cache.remove(source);
+    if (entry != null && !entry.explicitlyAdded) {
+      _implicitAnalysisEventsController
+          .add(new ImplicitAnalysisEvent(source, false));
+    }
+  }
+
+  /**
+   * Remove the given [source] from the priority order if it is in the list.
+   */
+  void _removeFromPriorityOrder(Source source) {
+    int count = _priorityOrder.length;
+    List<Source> newOrder = <Source>[];
+    for (int i = 0; i < count; i++) {
+      if (_priorityOrder[i] != source) {
+        newOrder.add(_priorityOrder[i]);
+      }
+    }
+    if (newOrder.length < count) {
+      analysisPriorityOrder = newOrder;
+    }
+  }
+
+  /**
+   * Create an entry for the newly added [source] and invalidate any sources
+   * that referenced the source before it existed.
+   */
+  void _sourceAvailable(Source source) {
+    // TODO(brianwilkerson) This method needs to check whether the source was
+    // previously being implicitly analyzed. If so, the cache entry needs to be
+    // update to reflect the new status and an event needs to be generated to
+    // inform clients that it is no longer being implicitly analyzed.
+    CacheEntry entry = _cache.get(source);
+    if (entry == null) {
+      _createCacheEntry(source, true);
+    } else {
+      entry.modificationTime = getModificationStamp(source);
+      entry.setState(CONTENT, CacheState.INVALID);
+    }
+  }
+
+  /**
+   * Invalidate the [source] that was changed and any sources that referenced
+   * the source before it existed.
+   */
+  void _sourceChanged(Source source) {
+    CacheEntry entry = _cache.get(source);
+    // If the source is removed, we don't care about it.
+    if (entry == null) {
+      return;
+    }
+    // Check whether the content of the source is the same as it was the last
+    // time.
+    String sourceContent = entry.getValue(CONTENT);
+    if (sourceContent != null) {
+      entry.setState(CONTENT, CacheState.FLUSHED);
+      try {
+        TimestampedData<String> fileContents = getContents(source);
+        if (fileContents.data == sourceContent) {
+          int time = fileContents.modificationTime;
+          for (CacheEntry entry in _entriesFor(source)) {
+            entry.modificationTime = time;
+          }
+          return;
+        }
+      } catch (e) {}
+    }
+    // We need to invalidate the cache.
+    {
+      Object delta = null;
+      if (AnalysisEngine.instance.limitInvalidationInTaskModel &&
+          AnalysisEngine.isDartFileName(source.fullName)) {
+        // TODO(scheglov) Incorrect implementation in general.
+        entry.setState(TOKEN_STREAM, CacheState.FLUSHED);
+        entry.setState(PARSED_UNIT, CacheState.FLUSHED);
+        List<Source> librarySources = getLibrariesContaining(source);
+        if (librarySources.length == 1) {
+          Source librarySource = librarySources[0];
+          CompilationUnit oldUnit =
+              getResolvedCompilationUnit2(source, librarySource);
+          if (oldUnit != null) {
+            CompilationUnit newUnit = parseCompilationUnit(source);
+            IncrementalCompilationUnitElementBuilder builder =
+                new IncrementalCompilationUnitElementBuilder(oldUnit, newUnit);
+            builder.build();
+            CompilationUnitElementDelta unitDelta = builder.unitDelta;
+            if (!unitDelta.hasDirectiveChange) {
+              DartDelta dartDelta = new DartDelta(source);
+              dartDelta.hasDirectiveChange = unitDelta.hasDirectiveChange;
+              unitDelta.addedDeclarations.forEach(dartDelta.elementAdded);
+              unitDelta.removedDeclarations.forEach(dartDelta.elementRemoved);
+//              print(
+//                  'dartDelta: add=${dartDelta.addedNames} remove=${dartDelta.removedNames}');
+              delta = dartDelta;
+              entry.setState(CONTENT, CacheState.INVALID, delta: delta);
+              return;
+            }
+          }
+        }
+      }
+      entry.setState(CONTENT, CacheState.INVALID);
+    }
+    for (WorkManager workManager in workManagers) {
+      workManager.applyChange(
+          Source.EMPTY_LIST, <Source>[source], Source.EMPTY_LIST);
+    }
+  }
+
+  /**
+   * Record that the give [source] has been deleted.
+   */
+  void _sourceDeleted(Source source) {
+    // TODO(brianwilkerson) Implement or remove this.
+//    SourceEntry sourceEntry = _cache.get(source);
+//    if (sourceEntry is HtmlEntry) {
+//      HtmlEntry htmlEntry = sourceEntry;
+//      htmlEntry.recordContentError(new CaughtException(
+//          new AnalysisException("This source was marked as being deleted"),
+//          null));
+//    } else if (sourceEntry is DartEntry) {
+//      DartEntry dartEntry = sourceEntry;
+//      HashSet<Source> libraries = new HashSet<Source>();
+//      for (Source librarySource in getLibrariesContaining(source)) {
+//        libraries.add(librarySource);
+//        for (Source dependentLibrary
+//            in getLibrariesDependingOn(librarySource)) {
+//          libraries.add(dependentLibrary);
+//        }
+//      }
+//      for (Source librarySource in libraries) {
+//        _invalidateLibraryResolution(librarySource);
+//      }
+//      dartEntry.recordContentError(new CaughtException(
+//          new AnalysisException("This source was marked as being deleted"),
+//          null));
+//    }
+    _removeFromPriorityOrder(source);
+  }
+
+  /**
+   * Record that the given [source] has been removed.
+   */
+  void _sourceRemoved(Source source) {
+    _removeFromCache(source);
+    _removeFromPriorityOrder(source);
+  }
+
+  /**
+   * TODO(scheglov) A hackish, limited incremental resolution implementation.
+   */
+  bool _tryPoorMansIncrementalResolution(Source unitSource, String newCode) {
+    return PerformanceStatistics.incrementalAnalysis.makeCurrentWhile(() {
+      incrementalResolutionValidation_lastUnitSource = null;
+      incrementalResolutionValidation_lastLibrarySource = null;
+      incrementalResolutionValidation_lastUnit = null;
+      // prepare the entry
+      CacheEntry sourceEntry = _cache.get(unitSource);
+      if (sourceEntry == null) {
+        return false;
+      }
+      // prepare the (only) library source
+      List<Source> librarySources = getLibrariesContaining(unitSource);
+      if (librarySources.length != 1) {
+        return false;
+      }
+      Source librarySource = librarySources[0];
+      CacheEntry unitEntry =
+          _cache.get(new LibrarySpecificUnit(librarySource, unitSource));
+      if (unitEntry == null) {
+        return false;
+      }
+      // prepare the library element
+      LibraryElement libraryElement = getLibraryElement(librarySource);
+      if (libraryElement == null) {
+        return false;
+      }
+      // prepare the existing unit
+      CompilationUnit oldUnit =
+          getResolvedCompilationUnit2(unitSource, librarySource);
+      if (oldUnit == null) {
+        return false;
+      }
+      // do resolution
+      Stopwatch perfCounter = new Stopwatch()..start();
+      PoorMansIncrementalResolver resolver = new PoorMansIncrementalResolver(
+          typeProvider,
+          unitSource,
+          null,
+          sourceEntry,
+          unitEntry,
+          oldUnit,
+          analysisOptions.incrementalApi,
+          analysisOptions);
+      bool success = resolver.resolve(newCode);
+      AnalysisEngine.instance.instrumentationService.logPerformance(
+          AnalysisPerformanceKind.INCREMENTAL,
+          perfCounter,
+          'success=$success,context_id=$_id,code_length=${newCode.length}');
+      if (!success) {
+        return false;
+      }
+      // if validation, remember the result, but throw it away
+      if (analysisOptions.incrementalValidation) {
+        incrementalResolutionValidation_lastUnitSource = oldUnit.element.source;
+        incrementalResolutionValidation_lastLibrarySource =
+            oldUnit.element.library.source;
+        incrementalResolutionValidation_lastUnit = oldUnit;
+        return false;
+      }
+      // prepare notice
+      {
+        ChangeNoticeImpl notice = getNotice(unitSource);
+        notice.resolvedDartUnit = oldUnit;
+        AnalysisErrorInfo errorInfo = getErrors(unitSource);
+        notice.setErrors(errorInfo.errors, errorInfo.lineInfo);
+      }
+      // schedule
+      dartWorkManager.unitIncrementallyResolved(librarySource, unitSource);
+      // OK
+      return true;
+    });
+  }
+}
+
+/**
+ * An object that manages the partitions that can be shared between analysis
+ * contexts.
+ */
+class PartitionManager {
+  /**
+   * A table mapping SDK's to the partitions used for those SDK's.
+   */
+  HashMap<DartSdk, SdkCachePartition> _sdkPartitions =
+      new HashMap<DartSdk, SdkCachePartition>();
+
+  /**
+   * Clear any cached data being maintained by this manager.
+   */
+  void clearCache() {
+    _sdkPartitions.clear();
+  }
+
+  /**
+   * Return the partition being used for the given [sdk], creating the partition
+   * if necessary.
+   */
+  SdkCachePartition forSdk(DartSdk sdk) {
+    // Call sdk.context now, because when it creates a new
+    // InternalAnalysisContext instance, it calls forSdk() again, so creates an
+    // SdkCachePartition instance.
+    // So, if we initialize context after "partition == null", we end up
+    // with two SdkCachePartition instances.
+    InternalAnalysisContext sdkContext = sdk.context;
+    // Check cache for an existing partition.
+    SdkCachePartition partition = _sdkPartitions[sdk];
+    if (partition == null) {
+      partition = new SdkCachePartition(sdkContext);
+      _sdkPartitions[sdk] = partition;
+    }
+    return partition;
+  }
+}
+
+/**
+ * Representation of a pending computation which is based on the results of
+ * analysis that may or may not have been completed.
+ */
+class PendingFuture<T> {
+  /**
+   * The context in which this computation runs.
+   */
+  final AnalysisContextImpl _context;
+
+  /**
+   * The target used by this computation to compute its value.
+   */
+  final AnalysisTarget target;
+
+  /**
+   * The function which implements the computation.
+   */
+  final PendingFutureComputer<T> _computeValue;
+
+  /**
+   * The completer that should be completed once the computation has succeeded.
+   */
+  CancelableCompleter<T> _completer;
+
+  PendingFuture(this._context, this.target, this._computeValue) {
+    _completer = new CancelableCompleter<T>(_onCancel);
+  }
+
+  /**
+   * Retrieve the future which will be completed when this object is
+   * successfully evaluated.
+   */
+  CancelableFuture<T> get future => _completer.future;
+
+  /**
+   * Execute [_computeValue], passing it the given [entry], and complete
+   * the pending future if it's appropriate to do so.  If the pending future is
+   * completed by this call, true is returned; otherwise false is returned.
+   *
+   * Once this function has returned true, it should not be called again.
+   *
+   * Other than completing the future, this method is free of side effects.
+   * Note that any code the client has attached to the future will be executed
+   * in a microtask, so there is no danger of side effects occurring due to
+   * client callbacks.
+   */
+  bool evaluate(CacheEntry entry) {
+    assert(!_completer.isCompleted);
+    try {
+      T result = _computeValue(entry);
+      if (result == null) {
+        return false;
+      } else {
+        _completer.complete(result);
+        return true;
+      }
+    } catch (exception, stackTrace) {
+      _completer.completeError(exception, stackTrace);
+      return true;
+    }
+  }
+
+  /**
+   * No further analysis updates are expected which affect this future, so
+   * complete it with an AnalysisNotScheduledError in order to avoid
+   * deadlocking the client.
+   */
+  void forciblyComplete() {
+    try {
+      throw new AnalysisNotScheduledError();
+    } catch (exception, stackTrace) {
+      _completer.completeError(exception, stackTrace);
+    }
+  }
+
+  void _onCancel() {
+    _context._cancelFuture(this);
+  }
+}
+
+/**
+ * An [AnalysisContext] that only contains sources for a Dart SDK.
+ */
+class SdkAnalysisContext extends AnalysisContextImpl {
+  @override
+  AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
+    if (factory == null) {
+      return super.createCacheFromSourceFactory(factory);
+    }
+    DartSdk sdk = factory.dartSdk;
+    if (sdk == null) {
+      throw new IllegalArgumentException(
+          "The source factory for an SDK analysis context must have a DartUriResolver");
+    }
+    return new AnalysisCache(<CachePartition>[
+      AnalysisEngine.instance.partitionManager_new.forSdk(sdk)
+    ]);
+  }
+}
+
+/**
+ * A helper class used to create futures for [AnalysisContextImpl].
+ * Using a helper class allows us to preserve the generic parameter T.
+ */
+class _AnalysisFutureHelper<T> {
+  final AnalysisContextImpl _context;
+
+  _AnalysisFutureHelper(this._context);
+
+  /**
+   * Return a future that will be completed with the result of calling
+   * [computeValue]. If [computeValue] returns non-`null`, the future will be
+   * completed immediately with the resulting value. If it returns `null`, then
+   * [scheduleComputation] is invoked to schedule analysis that will produce
+   * the required result, and [computeValue] will be re-executed in the future,
+   * after the next time the cached information for [target] has changed. If
+   * [computeValue] throws an exception, the future will fail with that
+   * exception.
+   *
+   * If the [computeValue] still returns `null` after there is no further
+   * analysis to be done for [target], then the future will be completed with
+   * the error AnalysisNotScheduledError.
+   *
+   * Since [computeValue] will be called while the state of analysis is being
+   * updated, it should be free of side effects so that it doesn't cause
+   * reentrant changes to the analysis state.
+   */
+  CancelableFuture<T> computeAsync(AnalysisTarget target,
+      T computeValue(CacheEntry entry), void scheduleComputation()) {
+    if (_context.isDisposed) {
+      // No further analysis is expected, so return a future that completes
+      // immediately with AnalysisNotScheduledError.
+      return new CancelableFuture.error(new AnalysisNotScheduledError());
+    }
+    CacheEntry entry = _context.getCacheEntry(target);
+    PendingFuture pendingFuture =
+        new PendingFuture<T>(_context, target, computeValue);
+    if (!pendingFuture.evaluate(entry)) {
+      _context._pendingFutureTargets
+          .putIfAbsent(target, () => <PendingFuture>[])
+          .add(pendingFuture);
+      scheduleComputation();
+    }
+    return pendingFuture.future;
+  }
+}