Move split_store.dart to the store/ folder and extract collections/codecs.

pkg/analysis_server/lib/src/index/split_store.dart

Index: pkg/analysis_server/lib/src/index/split_store.dart
diff --git a/pkg/analysis_server/lib/src/index/split_store.dart b/pkg/analysis_server/lib/src/index/split_store.dart
deleted file mode 100644
index c15a5b92a50d2db1a380bb362fe183fd2fc382f6..0000000000000000000000000000000000000000
--- a/pkg/analysis_server/lib/src/index/split_store.dart
+++ /dev/null
@@ -1,1167 +0,0 @@
-// 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 index.split.store;
-
-import 'dart:async';
-import 'dart:collection';
-import 'dart:io';
-import 'dart:typed_data';
-
-import 'package:analyzer/src/generated/element.dart';
-import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer/src/generated/index.dart';
-import 'package:analyzer/src/generated/java_engine.dart';
-import 'package:analyzer/src/generated/source.dart';
-
-
-/**
- * A helper that encodes/decodes [AnalysisContext]s from/to integers.
- *
- * TODO(scheglov) add API to remove [AnalysisContext]s.
- */
-class ContextCodec {
-  /**
-   * A table mapping contexts to their unique indices.
-   */
-  Map<AnalysisContext, int> _contextToIndex = new HashMap<AnalysisContext, int>(
-      );
-
-  /**
-   * A table mapping indices to the corresponding contexts.
-   */
-  Map<int, AnalysisContext> _indexToContext = new HashMap<int, AnalysisContext>(
-      );
-
-  /**
-   * The next id to assign.
-   */
-  int _nextId = 0;
-
-  /**
-   * Returns the [AnalysisContext] that corresponds to the given index.
-   */
-  AnalysisContext decode(int index) => _indexToContext[index];
-
-  /**
-   * Returns an unique index for the given [AnalysisContext].
-   */
-  int encode(AnalysisContext context) {
-    int index = _contextToIndex[context];
-    if (index == null) {
-      index = _nextId++;
-      _contextToIndex[context] = index;
-      _indexToContext[index] = context;
-    }
-    return index;
-  }
-
-  /**
-   * Removes the given [context].
-   */
-  void remove(AnalysisContext context) {
-    int id = _contextToIndex.remove(context);
-    if (id != null) {
-      _indexToContext.remove(id);
-    }
-  }
-}
-
-
-/**
- * A helper that encodes/decodes [Element]s to/from integers.
- */
-class ElementCodec {
-  /**
-   * A list that works as a mapping of integers to element encodings (in form of integer arrays).
-   */
-  List<List<int>> _indexToPath = [];
-
-  /**
-   * A table mapping element locations (in form of integer arrays) into a single integer.
-   */
-  IntArrayToIntMap _pathToIndex = new IntArrayToIntMap(10000, 0.75);
-
-  final StringCodec _stringCodec;
-
-  ElementCodec(this._stringCodec);
-
-  /**
-   * Returns an [Element] that corresponds to the given location.
-   *
-   * @param context the [AnalysisContext] to find [Element] in
-   * @param index an integer corresponding to the [Element]
-   * @return the [Element] or `null`
-   */
-  Element decode(AnalysisContext context, int index) {
-    List<int> path = _indexToPath[index];
-    List<String> components = _getLocationComponents(path);
-    ElementLocation location = new ElementLocationImpl.con3(components);
-    return context.getElement(location);
-  }
-
-  /**
-   * Returns a unique integer that corresponds to the given [Element].
-   */
-  int encode(Element element) {
-    List<int> path = _getLocationPath(element);
-    int index = _pathToIndex.get(path, -1);
-    if (index == -1) {
-      index = _indexToPath.length;
-      _pathToIndex.put(path, index);
-      _indexToPath.add(path);
-    }
-    return index;
-  }
-
-  List<String> _getLocationComponents(List<int> path) {
-    int length = path.length;
-    List<String> components = new List<String>();
-    for (int i = 0; i < length; i++) {
-      int componentId = path[i];
-      String component = _stringCodec.decode(componentId);
-      if (i < length - 1 && path[i + 1] < 0) {
-        component += '@${(-path[i + 1])}';
-        i++;
-      }
-      components.add(component);
-    }
-    return components;
-  }
-
-  List<int> _getLocationPath(Element element) {
-    List<String> components = element.location.components;
-    int length = components.length;
-    if (_hasLocalOffset(components)) {
-      List<int> path = new List<int>();
-      for (String component in components) {
-        int atOffset = component.indexOf('@');
-        if (atOffset == -1) {
-          path.add(_stringCodec.encode(component));
-        } else {
-          String preAtString = component.substring(0, atOffset);
-          String atString = component.substring(atOffset + 1);
-          path.add(_stringCodec.encode(preAtString));
-          path.add(-1 * int.parse(atString));
-        }
-      }
-      return path;
-    } else {
-      List<int> path = new List<int>.filled(length, 0);
-      for (int i = 0; i < length; i++) {
-        String component = components[i];
-        path[i] = _stringCodec.encode(component);
-      }
-      return path;
-    }
-  }
-
-  bool _hasLocalOffset(List<String> components) {
-    for (String component in components) {
-      if (component.indexOf('@') != -1) {
-        return true;
-      }
-    }
-    return false;
-  }
-}
-
-
-/**
- * A manager for files content.
- */
-abstract class FileManager {
-  /**
-   * Removes all files.
-   */
-  void clear();
-
-  /**
-   * Deletes the file with the given name.
-   */
-  void delete(String name);
-
-  /**
-   * Read the entire file contents as a list of bytes.
-   */
-  Future<List<int>> read(String name);
-
-  /**
-   * Write a list of bytes to a file.
-   */
-  Future write(String name, Uint8List bytes);
-}
-
-
-/**
- * A [FileManager] based [NodeManager].
- */
-class FileNodeManager implements NodeManager {
-  static int _VERSION = 1;
-
-  final ContextCodec contextCodec;
-
-  final ElementCodec elementCodec;
-
-  final StringCodec stringCodec;
-
-  final FileManager _fileManager;
-
-  int _locationCount = 0;
-
-  final Logger _logger;
-
-  Map<String, int> _nodeLocationCounts = {};
-
-  final RelationshipCodec _relationshipCodec;
-
-  FileNodeManager(this._fileManager, this._logger, this.stringCodec,
-      this.contextCodec, this.elementCodec, this._relationshipCodec);
-
-  @override
-  int get locationCount => _locationCount;
-
-  @override
-  void clear() {
-    _fileManager.clear();
-  }
-
-  @override
-  Future<IndexNode> getNode(String name) {
-    return _fileManager.read(name).then((List<int> bytes) {
-      if (bytes == null) {
-        return null;
-      }
-      _DataInputStream stream = new _DataInputStream(bytes);
-      return _readNode(stream);
-    }).catchError((e, stackTrace) {
-      _logger.logError2('Exception during reading index file ${name}',
-          new CaughtException(e, stackTrace));
-    });
-  }
-
-  @override
-  IndexNode newNode(AnalysisContext context) => new IndexNode(context,
-      elementCodec, _relationshipCodec);
-
-  @override
-  Future putNode(String name, IndexNode node) {
-    // update location count
-    {
-      _locationCount -= _getLocationCount(name);
-      int nodeLocationCount = node.locationCount;
-      _nodeLocationCounts[name] = nodeLocationCount;
-      _locationCount += nodeLocationCount;
-    }
-    // write the node
-    return new Future.microtask(() {
-      _DataOutputStream stream = new _DataOutputStream();
-      _writeNode(node, stream);
-      var bytes = stream.getBytes();
-      return _fileManager.write(name, bytes);
-    }).catchError((e, stackTrace) {
-      _logger.logError2('Exception during reading index file ${name}',
-          new CaughtException(e, stackTrace));
-    });
-  }
-
-  @override
-  void removeNode(String name) {
-    // update location count
-    _locationCount -= _getLocationCount(name);
-    _nodeLocationCounts.remove(name);
-    // remove node
-    _fileManager.delete(name);
-  }
-
-  int _getLocationCount(String name) {
-    int locationCount = _nodeLocationCounts[name];
-    return locationCount != null ? locationCount : 0;
-  }
-
-  RelationKeyData _readElementRelationKey(_DataInputStream stream) {
-    int elementId = stream.readInt();
-    int relationshipId = stream.readInt();
-    return new RelationKeyData.forData(elementId, relationshipId);
-  }
-
-  LocationData _readLocationData(_DataInputStream stream) {
-    int elementId = stream.readInt();
-    int offset = stream.readInt();
-    int length = stream.readInt();
-    return new LocationData.forData(elementId, offset, length);
-  }
-
-  IndexNode _readNode(_DataInputStream stream) {
-    // check version
-    {
-      int version = stream.readInt();
-      if (version != _VERSION) {
-        throw new StateError(
-            'Version ${_VERSION} expected, but ${version} found.');
-      }
-    }
-    // context
-    int contextId = stream.readInt();
-    AnalysisContext context = contextCodec.decode(contextId);
-    if (context == null) {
-      return null;
-    }
-    // relations
-    Map<RelationKeyData, List<LocationData>> relations = {};
-    int numRelations = stream.readInt();
-    for (int i = 0; i < numRelations; i++) {
-      RelationKeyData key = _readElementRelationKey(stream);
-      int numLocations = stream.readInt();
-      List<LocationData> locations = new List<LocationData>();
-      for (int j = 0; j < numLocations; j++) {
-        locations.add(_readLocationData(stream));
-      }
-      relations[key] = locations;
-    }
-    // create IndexNode
-    IndexNode node = new IndexNode(context, elementCodec, _relationshipCodec);
-    node.relations = relations;
-    return node;
-  }
-
-  void _writeElementRelationKey(_DataOutputStream stream, RelationKeyData key) {
-    stream.writeInt(key.elementId);
-    stream.writeInt(key.relationshipId);
-  }
-
-  void _writeNode(IndexNode node, _DataOutputStream stream) {
-    // version
-    stream.writeInt(_VERSION);
-    // context
-    {
-      AnalysisContext context = node.context;
-      int contextId = contextCodec.encode(context);
-      stream.writeInt(contextId);
-    }
-    // relations
-    Map<RelationKeyData, List<LocationData>> relations = node.relations;
-    stream.writeInt(relations.length);
-    relations.forEach((key, locations) {
-      _writeElementRelationKey(stream, key);
-      stream.writeInt(locations.length);
-      for (LocationData location in locations) {
-        stream.writeInt(location.elementId);
-        stream.writeInt(location.offset);
-        stream.writeInt(location.length);
-      }
-    });
-  }
-}
-
-
-/**
- * A single index file in-memory presentation.
- */
-class IndexNode {
-  final AnalysisContext context;
-
-  final ElementCodec _elementCodec;
-
-  Map<RelationKeyData, List<LocationData>> _relations =
-      new HashMap<RelationKeyData, List<LocationData>>();
-
-  final RelationshipCodec _relationshipCodec;
-
-  IndexNode(this.context, this._elementCodec, this._relationshipCodec);
-
-  /**
-   * Returns number of locations in this node.
-   */
-  int get locationCount {
-    int locationCount = 0;
-    for (List<LocationData> locations in _relations.values) {
-      locationCount += locations.length;
-    }
-    return locationCount;
-  }
-
-  /**
-   * Returns the recorded relations.
-   */
-  Map<RelationKeyData, List<LocationData>> get relations => _relations;
-
-  /**
-   * Sets relations data. This method is used during loading data from a storage.
-   */
-  void set relations(Map<RelationKeyData, List<LocationData>> relations) {
-    this._relations.clear();
-    this._relations.addAll(relations);
-  }
-
-  /**
-   * Return the locations of the elements that have the given relationship with the given element.
-   *
-   * @param element the the element that has the relationship with the locations to be returned
-   * @param relationship the [Relationship] between the given element and the locations to be
-   *          returned
-   */
-  List<Location> getRelationships(Element element, Relationship relationship) {
-    // prepare key
-    RelationKeyData key = new RelationKeyData.forObject(_elementCodec,
-        _relationshipCodec, element, relationship);
-    // find LocationData(s)
-    List<LocationData> locationDatas = _relations[key];
-    if (locationDatas == null) {
-      return Location.EMPTY_ARRAY;
-    }
-    // convert to Location(s)
-    List<Location> locations = [];
-    for (LocationData locationData in locationDatas) {
-      Location location = locationData.getLocation(context, _elementCodec);
-      if (location != null) {
-        locations.add(location);
-      }
-    }
-    return locations;
-  }
-
-  /**
-   * Records that the given element and location have the given relationship.
-   *
-   * @param element the element that is related to the location
-   * @param relationship the [Relationship] between the element and the location
-   * @param location the [Location] where relationship happens
-   */
-  void recordRelationship(Element element, Relationship relationship,
-      Location location) {
-    RelationKeyData key = new RelationKeyData.forObject(_elementCodec,
-        _relationshipCodec, element, relationship);
-    // prepare LocationData(s)
-    List<LocationData> locationDatas = _relations[key];
-    if (locationDatas == null) {
-      locationDatas = [];
-      _relations[key] = locationDatas;
-    }
-    // add new LocationData
-    locationDatas.add(new LocationData.forObject(_elementCodec, location));
-  }
-}
-
-
-class IntArrayToIntMap {
-  // TODO(scheglov) consider using Int32List
-  final Map<List<int>, int> map = new HashMap<List<int>, int>(equals:
-      _intArrayEquals, hashCode: _intArrayHashCode);
-
-  IntArrayToIntMap(int initialCapacity, double loadFactor);
-
-  int get(List<int> key, int defaultValue) {
-    int value = map[key];
-    if (value == null) {
-      return defaultValue;
-    }
-    return value;
-  }
-
-  void put(List<int> key, int value) {
-    map[key] = value;
-  }
-
-  static bool _intArrayEquals(List<int> a, List<int> b) {
-    int length = a.length;
-    if (length != b.length) {
-      return false;
-    }
-    for (int i = 0; i < length; i++) {
-      if (a[i] != b[i]) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  static int _intArrayHashCode(List<int> key) {
-    return key.fold(0, (int result, int item) {
-      return 31 * result + item;
-    });
-  }
-}
-
-
-class IntToIntSetMap {
-  // TODO(scheglov) consider using Int32List
-  final Map<int, List<int>> _map = new HashMap<int, List<int>>();
-  int _size = 0;
-
-  IntToIntSetMap(int initialCapacity, double loadFactor);
-
-  int get length => _size;
-
-  void add(int key, int value) {
-    List<int> values = _map[key];
-    if (values == null) {
-      values = new List<int>();
-      _map[key] = values;
-    }
-    if (values.indexOf(value) == -1) {
-      values.add(value);
-      _size++;
-    }
-  }
-
-  void clear() {
-    _map.clear();
-    _size = 0;
-  }
-
-  List<int> get(int key) {
-    List<int> values = _map[key];
-    if (values == null) {
-      values = <int>[];
-    }
-    return values;
-  }
-}
-
-
-/**
- * A container with information about a [Location].
- */
-class LocationData {
-  final int elementId;
-  final int length;
-  final int offset;
-
-  LocationData.forData(this.elementId, this.offset, this.length);
-
-  LocationData.forObject(ElementCodec elementCodec, Location location)
-      : elementId = elementCodec.encode(location.element),
-        offset = location.offset,
-        length = location.length;
-
-  @override
-  int get hashCode {
-    return 31 * (31 * elementId + offset) + length;
-  }
-
-  @override
-  bool operator ==(Object obj) {
-    if (obj is! LocationData) {
-      return false;
-    }
-    LocationData other = obj;
-    return other.elementId == elementId && other.offset == offset &&
-        other.length == length;
-  }
-
-  /**
-   * Returns a {@link Location} that is represented by this {@link LocationData}.
-   */
-  Location getLocation(AnalysisContext context, ElementCodec elementCodec) {
-    Element element = elementCodec.decode(context, elementId);
-    if (element == null) {
-      return null;
-    }
-    return new Location(element, offset, length);
-  }
-}
-
-
-/**
- * A manager for [IndexNode]s.
- */
-abstract class NodeManager {
-  /**
-   * The shared {@link ContextCodec} instance.
-   */
-  ContextCodec get contextCodec;
-
-  /**
-   * The shared {@link ElementCodec} instance.
-   */
-  ElementCodec get elementCodec;
-
-  /**
-   * A number of locations in all nodes.
-   */
-  int get locationCount;
-
-  /**
-   * The shared {@link StringCodec} instance.
-   */
-  StringCodec get stringCodec;
-
-  /**
-   * Removes all nodes.
-   */
-  void clear();
-
-  /**
-   * Returns the {@link IndexNode} with the given name, {@code null} if not found.
-   */
-  Future<IndexNode> getNode(String name);
-
-  /**
-   * Returns a new {@link IndexNode}.
-   */
-  IndexNode newNode(AnalysisContext context);
-
-  /**
-   * Associates the given {@link IndexNode} with the given name.
-   */
-  void putNode(String name, IndexNode node);
-
-  /**
-   * Removes the {@link IndexNode} with the given name.
-   */
-  void removeNode(String name);
-}
-
-
-/**
- * An [Element] to [Location] relation key.
- */
-class RelationKeyData {
-  final int elementId;
-  final int relationshipId;
-
-  RelationKeyData.forData(this.elementId, this.relationshipId);
-
-  RelationKeyData.forObject(ElementCodec elementCodec,
-      RelationshipCodec relationshipCodec, Element element, Relationship relationship)
-      : elementId = elementCodec.encode(element),
-        relationshipId = relationshipCodec.encode(relationship);
-
-  @override
-  int get hashCode {
-    return 31 * elementId + relationshipId;
-  }
-
-  @override
-  bool operator ==(Object obj) {
-    if (obj is! RelationKeyData) {
-      return false;
-    }
-    RelationKeyData other = obj;
-    return other.elementId == elementId && other.relationshipId ==
-        relationshipId;
-  }
-}
-
-
-/**
- * A helper that encodes/decodes [Relationship]s to/from integers.
- */
-class RelationshipCodec {
-  final StringCodec _stringCodec;
-
-  RelationshipCodec(this._stringCodec);
-
-  Relationship decode(int idIndex) {
-    String id = _stringCodec.decode(idIndex);
-    return Relationship.getRelationship(id);
-  }
-
-  int encode(Relationship relationship) {
-    String id = relationship.identifier;
-    return _stringCodec.encode(id);
-  }
-}
-
-
-/**
- * An [IndexStore] which keeps index information in separate nodes for each unit.
- */
-class SplitIndexStore implements IndexStore {
-  /**
-   * The [ContextCodec] to encode/decode [AnalysisContext]s.
-   */
-  ContextCodec _contextCodec;
-
-  /**
-   * Information about "universe" elements.
-   * We need to keep them together to avoid loading of all index nodes.
-   *
-   * Order of keys: contextId, nodeId, Relationship.
-   */
-  Map<int, Map<int, Map<Relationship, List<LocationData>>>>
-      _contextNodeRelations = new HashMap<int, Map<int, Map<Relationship,
-      List<LocationData>>>>();
-
-  /**
-   * The mapping of library [Source] to the [Source]s of part units.
-   */
-  Map<AnalysisContext, Map<Source, Set<Source>>> _contextToLibraryToUnits =
-      new HashMap<AnalysisContext, Map<Source, Set<Source>>>();
-
-  /**
-   * The mapping of unit [Source] to the [Source]s of libraries it is used in.
-   */
-  Map<AnalysisContext, Map<Source, Set<Source>>> _contextToUnitToLibraries =
-      new HashMap<AnalysisContext, Map<Source, Set<Source>>>();
-
-  int _currentContextId = 0;
-
-  IndexNode _currentNode;
-
-  String _currentNodeName;
-
-  int _currentNodeNameId = 0;
-
-  /**
-   * The [ElementCodec] to encode/decode [Element]s.
-   */
-  ElementCodec _elementCodec;
-
-  /**
-   * A table mapping element names to the node names that may have relations with elements with
-   * these names.
-   */
-  IntToIntSetMap _nameToNodeNames = new IntToIntSetMap(10000, 0.75);
-
-  /**
-   * The [NodeManager] to get/put [IndexNode]s.
-   */
-  final NodeManager _nodeManager;
-
-  /**
-   * The set of known [Source]s.
-   */
-  Set<Source> _sources = new HashSet<Source>();
-
-  /**
-   * The [StringCodec] to encode/decode [String]s.
-   */
-  StringCodec _stringCodec;
-
-  SplitIndexStore(this._nodeManager) {
-    this._contextCodec = _nodeManager.contextCodec;
-    this._elementCodec = _nodeManager.elementCodec;
-    this._stringCodec = _nodeManager.stringCodec;
-  }
-
-  @override
-  String get statistics =>
-      '[${_nodeManager.locationCount} locations, ${_sources.length} sources, ${_nameToNodeNames.length} names]';
-
-  @override
-  bool aboutToIndexDart(AnalysisContext context,
-      CompilationUnitElement unitElement) {
-    context = _unwrapContext(context);
-    // may be already disposed in other thread
-    if (context.isDisposed) {
-      return false;
-    }
-    // validate unit
-    if (unitElement == null) {
-      return false;
-    }
-    LibraryElement libraryElement = unitElement.library;
-    if (libraryElement == null) {
-      return false;
-    }
-    CompilationUnitElement definingUnitElement =
-        libraryElement.definingCompilationUnit;
-    if (definingUnitElement == null) {
-      return false;
-    }
-    // prepare sources
-    Source library = definingUnitElement.source;
-    Source unit = unitElement.source;
-    // special handling for the defining library unit
-    if (unit == library) {
-      // prepare new parts
-      Set<Source> newParts = new Set();
-      for (CompilationUnitElement part in libraryElement.parts) {
-        newParts.add(part.source);
-      }
-      // prepare old parts
-      Map<Source, Set<Source>> libraryToUnits =
-          _contextToLibraryToUnits[context];
-      if (libraryToUnits == null) {
-        libraryToUnits = {};
-        _contextToLibraryToUnits[context] = libraryToUnits;
-      }
-      Set<Source> oldParts = libraryToUnits[library];
-      // check if some parts are not in the library now
-      if (oldParts != null) {
-        Set<Source> noParts = oldParts.difference(newParts);
-        for (Source noPart in noParts) {
-          _removeLocations(context, library, noPart);
-        }
-      }
-      // remember new parts
-      libraryToUnits[library] = newParts;
-    }
-    // remember library/unit relations
-    _recordUnitInLibrary(context, library, unit);
-    _recordLibraryWithUnit(context, library, unit);
-    _sources.add(library);
-    _sources.add(unit);
-    // prepare node
-    String libraryName = library.fullName;
-    String unitName = unit.fullName;
-    int libraryNameIndex = _stringCodec.encode(libraryName);
-    int unitNameIndex = _stringCodec.encode(unitName);
-    _currentNodeName = '${libraryNameIndex}_${unitNameIndex}.index';
-    _currentNodeNameId = _stringCodec.encode(_currentNodeName);
-    _currentNode = _nodeManager.newNode(context);
-    _currentContextId = _contextCodec.encode(context);
-    // remove Universe information for the current node
-    for (Map<int, dynamic> nodeRelations in _contextNodeRelations.values) {
-      nodeRelations.remove(_currentNodeNameId);
-    }
-    // done
-    return true;
-  }
-
-  @override
-  bool aboutToIndexHtml(AnalysisContext context, HtmlElement htmlElement) {
-    context = _unwrapContext(context);
-    // may be already disposed in other thread
-    if (context.isDisposed) {
-      return false;
-    }
-    // remove locations
-    Source source = htmlElement.source;
-    _removeLocations(context, null, source);
-    // remember library/unit relations
-    _recordUnitInLibrary(context, null, source);
-    // prepare node
-    String sourceName = source.fullName;
-    int sourceNameIndex = _stringCodec.encode(sourceName);
-    _currentNodeName = '${sourceNameIndex}.index';
-    _currentNodeNameId = _stringCodec.encode(_currentNodeName);
-    _currentNode = _nodeManager.newNode(context);
-    return true;
-  }
-
-  @override
-  void clear() {
-    _nodeManager.clear();
-    _nameToNodeNames.clear();
-  }
-
-  @override
-  void doneIndex() {
-    if (_currentNode != null) {
-      _nodeManager.putNode(_currentNodeName, _currentNode);
-      _currentNodeName = null;
-      _currentNodeNameId = -1;
-      _currentNode = null;
-      _currentContextId = -1;
-    }
-  }
-
-  @override
-  List<Location> getRelationships(Element element, Relationship relationship) {
-    // TODO(scheglov) make IndexStore interface async
-    return <Location>[];
-  }
-
-  Future<List<Location>> getRelationshipsAsync(Element element,
-      Relationship relationship) {
-    // special support for UniverseElement
-    if (identical(element, UniverseElement.INSTANCE)) {
-      List<Location> locations = _getRelationshipsUniverse(relationship);
-      return new Future.value(locations);
-    }
-    // prepare node names
-    String name = _getElementName(element);
-    int nameId = _stringCodec.encode(name);
-    List<int> nodeNameIds = _nameToNodeNames.get(nameId);
-    // prepare Future(s) for reading each IndexNode
-    List<Future<List<Location>>> nodeFutures = <Future<List<Location>>>[];
-    for (int nodeNameId in nodeNameIds) {
-      String nodeName = _stringCodec.decode(nodeNameId);
-      Future<IndexNode> nodeFuture = _nodeManager.getNode(nodeName);
-      Future<List<Location>> locationsFuture = nodeFuture.then((node) {
-        if (node == null) {
-          // TODO(scheglov) remove node
-          return Location.EMPTY_ARRAY;
-        }
-        return node.getRelationships(element, relationship);
-      });
-      nodeFutures.add(locationsFuture);
-    }
-    // return Future that merges separate IndexNode Location(s)
-    return Future.wait(nodeFutures).then((List<List<Location>> locationsList) {
-      List<Location> allLocations = <Location>[];
-      for (List<Location> locations in locationsList) {
-        allLocations.addAll(locations);
-      }
-      return allLocations;
-    });
-  }
-
-  @override
-  void recordRelationship(Element element, Relationship relationship,
-      Location location) {
-    if (element == null || location == null) {
-      return;
-    }
-    // special support for UniverseElement
-    if (identical(element, UniverseElement.INSTANCE)) {
-      _recordRelationshipUniverse(relationship, location);
-      return;
-    }
-    // other elements
-    _recordNodeNameForElement(element);
-    _currentNode.recordRelationship(element, relationship, location);
-  }
-
-  @override
-  void removeContext(AnalysisContext context) {
-    context = _unwrapContext(context);
-    if (context == null) {
-      return;
-    }
-    // remove sources
-    removeSources(context, null);
-    // remove context information
-    _contextToLibraryToUnits.remove(context);
-    _contextToUnitToLibraries.remove(context);
-    _contextNodeRelations.remove(_contextCodec.encode(context));
-    // remove context from codec
-    _contextCodec.remove(context);
-  }
-
-  @override
-  void removeSource(AnalysisContext context, Source source) {
-    context = _unwrapContext(context);
-    if (context == null) {
-      return;
-    }
-    // remove nodes for unit/library pairs
-    Map<Source, Set<Source>> unitToLibraries =
-        _contextToUnitToLibraries[context];
-    if (unitToLibraries != null) {
-      Set<Source> libraries = unitToLibraries.remove(source);
-      if (libraries != null) {
-        for (Source library in libraries) {
-          _removeLocations(context, library, source);
-        }
-      }
-    }
-    // remove nodes for library/unit pairs
-    Map<Source, Set<Source>> libraryToUnits = _contextToLibraryToUnits[context];
-    if (libraryToUnits != null) {
-      Set<Source> units = libraryToUnits.remove(source);
-      if (units != null) {
-        for (Source unit in units) {
-          _removeLocations(context, source, unit);
-        }
-      }
-    }
-  }
-
-  @override
-  void removeSources(AnalysisContext context, SourceContainer container) {
-    context = _unwrapContext(context);
-    if (context == null) {
-      return;
-    }
-    // remove nodes for unit/library pairs
-    Map<Source, Set<Source>> unitToLibraries =
-        _contextToUnitToLibraries[context];
-    if (unitToLibraries != null) {
-      List<Source> units = new List<Source>.from(unitToLibraries.keys);
-      for (Source source in units) {
-        if (container == null || container.contains(source)) {
-          removeSource(context, source);
-        }
-      }
-    }
-    // remove nodes for library/unit pairs
-    Map<Source, Set<Source>> libraryToUnits = _contextToLibraryToUnits[context];
-    if (libraryToUnits != null) {
-      List<Source> libraries = new List<Source>.from(libraryToUnits.keys);
-      for (Source source in libraries) {
-        if (container == null || container.contains(source)) {
-          removeSource(context, source);
-        }
-      }
-    }
-  }
-
-  String _getElementName(Element element) => element.name;
-
-  List<Location> _getRelationshipsUniverse(Relationship relationship) {
-    List<Location> locations = [];
-    _contextNodeRelations.forEach((contextId, contextRelations) {
-      AnalysisContext context = _contextCodec.decode(contextId);
-      if (context != null) {
-        for (Map<Relationship, List<LocationData>> nodeRelations in
-            contextRelations.values) {
-          List<LocationData> nodeLocations = nodeRelations[relationship];
-          if (nodeLocations != null) {
-            for (LocationData locationData in nodeLocations) {
-              Location location = locationData.getLocation(context,
-                  _elementCodec);
-              if (location != null) {
-                locations.add(location);
-              }
-            }
-          }
-        }
-      }
-    });
-    return locations;
-  }
-
-  void _recordLibraryWithUnit(AnalysisContext context, Source library,
-      Source unit) {
-    Map<Source, Set<Source>> libraryToUnits = _contextToLibraryToUnits[context];
-    if (libraryToUnits == null) {
-      libraryToUnits = {};
-      _contextToLibraryToUnits[context] = libraryToUnits;
-    }
-    Set<Source> units = libraryToUnits[library];
-    if (units == null) {
-      units = new Set();
-      libraryToUnits[library] = units;
-    }
-    units.add(unit);
-  }
-
-  void _recordNodeNameForElement(Element element) {
-    String name = _getElementName(element);
-    int nameId = _stringCodec.encode(name);
-    _nameToNodeNames.add(nameId, _currentNodeNameId);
-  }
-
-  void _recordRelationshipUniverse(Relationship relationship,
-      Location location) {
-    // in current context
-    Map<int, Map<Relationship, List<LocationData>>> nodeRelations =
-        _contextNodeRelations[_currentContextId];
-    if (nodeRelations == null) {
-      nodeRelations = {};
-      _contextNodeRelations[_currentContextId] = nodeRelations;
-    }
-    // in current node
-    Map<Relationship, List<LocationData>> relations =
-        nodeRelations[_currentNodeNameId];
-    if (relations == null) {
-      relations = {};
-      nodeRelations[_currentNodeNameId] = relations;
-    }
-    // for the given relationship
-    List<LocationData> locations = relations[relationship];
-    if (locations == null) {
-      locations = [];
-      relations[relationship] = locations;
-    }
-    // record LocationData
-    locations.add(new LocationData.forObject(_elementCodec, location));
-  }
-
-  void _recordUnitInLibrary(AnalysisContext context, Source library,
-      Source unit) {
-    Map<Source, Set<Source>> unitToLibraries =
-        _contextToUnitToLibraries[context];
-    if (unitToLibraries == null) {
-      unitToLibraries = {};
-      _contextToUnitToLibraries[context] = unitToLibraries;
-    }
-    Set<Source> libraries = unitToLibraries[unit];
-    if (libraries == null) {
-      libraries = new Set();
-      unitToLibraries[unit] = libraries;
-    }
-    libraries.add(library);
-  }
-
-  /**
-   * Removes locations recorded in the given library/unit pair.
-   */
-  void _removeLocations(AnalysisContext context, Source library, Source unit) {
-    // remove node
-    String libraryName = library != null ? library.fullName : null;
-    String unitName = unit.fullName;
-    int libraryNameIndex = _stringCodec.encode(libraryName);
-    int unitNameIndex = _stringCodec.encode(unitName);
-    String nodeName = '${libraryNameIndex}_${unitNameIndex}.index';
-    _nodeManager.removeNode(nodeName);
-    // remove source
-    _sources.remove(library);
-    _sources.remove(unit);
-  }
-
-  /**
-   * When logging is on, [AnalysisEngine] actually creates
-   * [InstrumentedAnalysisContextImpl], which wraps [AnalysisContextImpl] used to create
-   * actual [Element]s. So, in index we have to unwrap [InstrumentedAnalysisContextImpl]
-   * when perform any operation.
-   */
-  AnalysisContext _unwrapContext(AnalysisContext context) {
-    if (context is InstrumentedAnalysisContextImpl) {
-      context = (context as InstrumentedAnalysisContextImpl).basis;
-    }
-    return context;
-  }
-}
-
-
-/**
- * A helper that encodes/decodes [String]s from/to integers.
- */
-class StringCodec {
-  /**
-   * A table mapping names to their unique indices.
-   */
-  final Map<String, int> nameToIndex = {};
-
-  /**
-   * A table mapping indices to the corresponding strings.
-   */
-  List<String> _indexToName = [];
-
-  /**
-   * Returns the [String] that corresponds to the given index.
-   */
-  String decode(int index) => _indexToName[index];
-
-  /**
-   * Returns an unique index for the given [String].
-   */
-  int encode(String name) {
-    int index = nameToIndex[name];
-    if (index == null) {
-      index = _indexToName.length;
-      nameToIndex[name] = index;
-      _indexToName.add(name);
-    }
-    return index;
-  }
-}
-
-
-class _DataInputStream {
-  ByteData _byteData;
-  int _byteOffset = 0;
-
-  _DataInputStream(List<int> bytes) {
-    ByteBuffer buffer = new Uint8List.fromList(bytes).buffer;
-    _byteData = new ByteData.view(buffer);
-  }
-
-  int readInt() {
-    int result = _byteData.getInt32(_byteOffset);
-    _byteOffset += 4;
-    return result;
-  }
-}
-
-
-class _DataOutputStream {
-  BytesBuilder _buffer = new BytesBuilder();
-
-  Uint8List getBytes() {
-    return new Uint8List.fromList(_buffer.takeBytes());
-  }
-
-  void writeInt(int value) {
-    _buffer.addByte((value & 0xFF000000) >> 24);
-    _buffer.addByte((value & 0x00FF0000) >> 16);
-    _buffer.addByte((value & 0x0000FF00) >> 8);
-    _buffer.addByte(value & 0xFF);
-  }
-}