Implemention of the 'analysis.overrides' notification.

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

Index: pkg/analysis_server/lib/src/computer/computer_overrides.dart
diff --git a/pkg/analysis_server/lib/src/computer/computer_overrides.dart b/pkg/analysis_server/lib/src/computer/computer_overrides.dart
new file mode 100644
index 0000000000000000000000000000000000000000..832fa7ec8833dd4bb47695f0e69ee22c58643b8e
--- /dev/null
+++ b/pkg/analysis_server/lib/src/computer/computer_overrides.dart
@@ -0,0 +1,159 @@
+// 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.overrides;
+
+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 class member overrides in a Dart [CompilationUnit].
+ */
+class DartUnitOverridesComputer {
+  final CompilationUnit _unit;
+
+  final List<Override> _overrides = <Override>[];
+  engine.ClassElement _currentClass;
+
+  DartUnitOverridesComputer(this._unit);
+
+  /**
+   * Returns the computed occurrences, not `null`.
+   */
+  List<Map<String, Object>> compute() {
+    for (CompilationUnitMember unitMember in _unit.declarations) {
+      if (unitMember is ClassDeclaration) {
+        _currentClass = unitMember.element;
+        for (ClassMember classMember in unitMember.members) {
+          if (classMember is MethodDeclaration) {
+            SimpleIdentifier nameNode = classMember.name;
+            _addOverride(nameNode.offset, nameNode.length, nameNode.name);
+          }
+          if (classMember is FieldDeclaration) {
+            List<VariableDeclaration> fields = classMember.fields.variables;
+            for (VariableDeclaration field in fields) {
+              SimpleIdentifier nameNode = field.name;
+              _addOverride(nameNode.offset, nameNode.length, nameNode.name);
+            }
+          }
+        }
+      }
+    }
+    return _overrides.map((override) => override.toJson()).toList();
+  }
+
+  void _addOverride(int offset, int length, String name) {
+    // super
+    engine.Element superEngineElement;
+    {
+      engine.InterfaceType superType = _currentClass.supertype;
+      if (superType != null) {
+        superEngineElement = _lookupMember(superType.element, name);
+      }
+    }
+    // interfaces
+    List<engine.Element> interfaceEngineElements = <engine.Element>[];
+    for (engine.InterfaceType interfaceType in _currentClass.interfaces) {
+      engine.ClassElement interfaceElement = interfaceType.element;
+      engine.Element interfaceMember = _lookupMember(interfaceElement, name);
+      if (interfaceMember != null) {
+        interfaceEngineElements.add(interfaceMember);
+      }
+    }
+    // is there any override?
+    if (superEngineElement != null || interfaceEngineElements.isNotEmpty) {
+      Element superElement = superEngineElement != null ?
+          new Element.fromEngine(superEngineElement) : null;
+      List<Element> interfaceElements = interfaceEngineElements.map(
+          (engineElement) {
+        return new Element.fromEngine(engineElement);
+      }).toList();
+      _overrides.add(new Override(offset, length, superElement,
+          interfaceElements));
+    }
+  }
+
+  static engine.Element _lookupMember(engine.ClassElement classElement,
+      String name) {
+    if (classElement == null) {
+      return null;
+    }
+    engine.LibraryElement library = classElement.library;
+    // method
+    engine.Element member = classElement.lookUpMethod(name, library);
+    if (member != null) {
+      return member;
+    }
+    // getter
+    member = classElement.lookUpGetter(name, library);
+    if (member != null) {
+      return member;
+    }
+    // setter
+    member = classElement.lookUpSetter(name + '=', library);
+    if (member != null) {
+      return member;
+    }
+    // not found
+    return null;
+  }
+}
+
+
+class Override {
+  final int offset;
+  final int length;
+  final Element superclassElement;
+  final List<Element> interfaceElements;
+
+  Override(this.offset, this.length, this.superclassElement,
+      this.interfaceElements);
+
+  factory Override.fromJson(Map<String, Object> map) {
+    int offset = map[OFFSET];
+    int length = map[LENGTH];
+    // super
+    Element superclassElement = null;
+    {
+      Map<String, Object> superJson = map[SUPER_CLASS_ELEMENT];
+      if (superJson != null) {
+        superclassElement = new Element.fromJson(superJson);
+      }
+    }
+    // interfaces
+    List<Element> interfaceElements = null;
+    {
+      List<Map<String, Object>> jsonList = map[INTERFACE_ELEMENTS];
+      if (jsonList != null) {
+        interfaceElements = <Element>[];
+        for (Map<String, Object> json in jsonList) {
+          interfaceElements.add(new Element.fromJson(json));
+        }
+      }
+    }
+    // done
+    return new Override(offset, length, superclassElement, interfaceElements);
+  }
+
+  Map<String, Object> toJson() {
+    Map<String, Object> json = <String, Object>{};
+    json[OFFSET] = offset;
+    json[LENGTH] = length;
+    if (superclassElement != null) {
+      json[SUPER_CLASS_ELEMENT] = superclassElement.toJson();
+    }
+    if (interfaceElements != null && interfaceElements.isNotEmpty) {
+      json[INTERFACE_ELEMENTS] = interfaceElements.map((element) {
+        return element.toJson();
+      }).toList();
+    }
+    return json;
+  }
+
+  @override
+  String toString() => toJson().toString();
+}