Implementation for 'analysis.occurrences' notification.

pkg/analysis_server/lib/src/computer/computer_occurrences.dart

+// 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 computer.occurrences;
+
+import 'dart:collection';
+
+import 'package:analysis_server/src/computer/element.dart';
+import 'package:analysis_server/src/constants.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart' as engine;
+
+
+/**
+ * A computer for elements occurrences in a Dart [CompilationUnit].
+ */
+class DartUnitOccurrencesComputer {
+  final CompilationUnit _unit;
+
+  final Map<engine.Element, List<int>> _elementsOffsets =
+      new HashMap<engine.Element, List<int>>();
+
+  DartUnitOccurrencesComputer(this._unit);
+
+  /**
+   * Returns the computed occurrences, not `null`.
+   */
+  List<Map<String, Object>> compute() {
+    _unit.accept(new _DartUnitOccurrencesComputerVisitor(this));
+    List<Occurrences> occurrences = <Occurrences>[];
+    _elementsOffsets.forEach((engineElement, offsets) {
+      Element serverElement = new Element.fromEngine(engineElement);
+      int length = engineElement.displayName.length;
+      occurrences.add(new Occurrences(serverElement, offsets, length));
+    });
+    return occurrences.map((occurrences) => occurrences.toJson()).toList();
+  }
+
+  void _addOccurrence(engine.Element element, int offset) {
+    List<int> offsets = _elementsOffsets[element];
+    if (offsets == null) {
+      offsets = <int>[];
+      _elementsOffsets[element] = offsets;
+    }
+    offsets.add(offset);
+  }
+}
+
+
+class Occurrences {
+  final Element element;
+  final List<int> offsets;
+  final int length;
+
+  Occurrences(this.element, this.offsets, this.length);
+
+  factory Occurrences.fromJson(Map<String, Object> map) {
+    Element element = new Element.fromJson(map[ELEMENT]);
+    List<int> offsets = map[OFFSETS];
+    int length = map[LENGTH];
+    return new Occurrences(element, offsets, length);
+  }
+
+  Map<String, Object> toJson() {
+    Map<String, Object> json = new HashMap<String, Object>();
+    json[ELEMENT] = element.toJson();
+    json[OFFSETS] = offsets;
+    json[LENGTH] = length;
+    return json;
+  }
+
+  @override
+  String toString() => toJson().toString();
+}
+
+
+class _DartUnitOccurrencesComputerVisitor extends RecursiveAstVisitor {
+  final DartUnitOccurrencesComputer computer;
+
+  _DartUnitOccurrencesComputerVisitor(this.computer);
+
+  @override
+  visitSimpleIdentifier(SimpleIdentifier node) {
+    engine.Element element = node.bestElement;
+    if (element != null) {
+      computer._addOccurrence(element, node.offset);
+    }
+    return super.visitSimpleIdentifier(node);
+  }
+}