Introduce code to resynthesize element models from summaries.

pkg/analyzer/lib/src/generated/element_handle.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 analyzer.src.generated.element_handle;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/engine.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/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 /**
  * Instances of the class `ClassElementHandle` implement a handle to a `ClassElement`.
  */
 class ClassElementHandle extends ElementHandle implements ClassElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ClassElementHandle(ClassElement element) : super(element);
+  ClassElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   List<PropertyAccessorElement> get accessors => actualElement.accessors;
 
   @override
   ClassElement get actualElement => super.actualElement as ClassElement;
 
   @override
   List<InterfaceType> get allSupertypes => actualElement.allSupertypes;
 
@@ skipping 121 matching lines @@
  * Instances of the class `CompilationUnitElementHandle` implements a handle to a
  * [CompilationUnitElement].
  */
 class CompilationUnitElementHandle extends ElementHandle
     implements CompilationUnitElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  CompilationUnitElementHandle(CompilationUnitElement element) : super(element);
+  CompilationUnitElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   List<PropertyAccessorElement> get accessors => actualElement.accessors;
 
   @override
   CompilationUnitElement get actualElement =>
       super.actualElement as CompilationUnitElement;
 
   @override
   LibraryElement get enclosingElement =>
@@ skipping 53 matching lines @@
  * Instances of the class `ConstructorElementHandle` implement a handle to a
  * `ConstructorElement`.
  */
 class ConstructorElementHandle extends ExecutableElementHandle
     implements ConstructorElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ConstructorElementHandle(ConstructorElement element) : super(element);
+  ConstructorElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ConstructorElement get actualElement =>
       super.actualElement as ConstructorElement;
 
   @override
   ClassElement get enclosingElement => actualElement.enclosingElement;
 
   @override
   bool get isConst => actualElement.isConst;
@@ skipping 25 matching lines @@
  * The abstract class `ElementHandle` implements the behavior common to objects that implement
  * a handle to an [Element].
  */
 abstract class ElementHandle implements Element {
   /**
    * The unique integer identifier of this element.
    */
   final int id = 0;
 
   /**
-   * The context in which the element is defined.
+   * The [ElementResynthesizer] which will be used to resynthesize elements on
+   * demand.
    */
-  AnalysisContext _context;
+  final ElementResynthesizer _resynthesizer;
 
   /**
    * The location of this element, used to reconstitute the element if it has been garbage
    * collected.
    */
-  ElementLocation _location;
+  final ElementLocation _location;
 
   /**
    * A reference to the element being referenced by this handle, or `null` if the element has
    * been garbage collected.
    */
-  WeakReference<Element> _elementReference;
+  Element _elementReference;
 
   /**
-   * Initialize a newly created element handle to represent the given element.
-   *
-   * @param element the element being represented
+   * Initialize a newly created element handle to represent the element at the
+   * given [_location].  [_resynthesizer] will be used to resynthesize the
+   * element when needed.
    */
-  ElementHandle(Element element) {
-    _context = element.context;
-    _location = element.location;
-    _elementReference = new WeakReference<Element>(element);
-  }
+  ElementHandle(this._resynthesizer, this._location);
 
   /**
    * Return the element being represented by this handle, reconstituting the element if the
    * reference has been set to `null`.
    *
    * @return the element being represented by this handle
    */
   Element get actualElement {
-    Element element = _elementReference.get();
-    if (element == null) {
-      element = _context.getElement(_location);
-      _elementReference = new WeakReference<Element>(element);
+    if (_elementReference == null) {
+      _elementReference = _resynthesizer.getElement(_location);
     }
-    return element;
+    return _elementReference;
   }
 
   @override
-  AnalysisContext get context => _context;
+  AnalysisContext get context => _resynthesizer.context;
 
   @override
   String get displayName => actualElement.displayName;
 
   @override
   SourceRange get docRange => actualElement.docRange;
 
   @override
   Element get enclosingElement => actualElement.enclosingElement;
 
@@ skipping 63 matching lines @@
       actualElement.getExtendedDisplayName(shortName);
 
   @override
   bool isAccessibleIn(LibraryElement library) =>
       actualElement.isAccessibleIn(library);
 
   @override
   void visitChildren(ElementVisitor visitor) {
     actualElement.visitChildren(visitor);
   }
-
-  /**
-   * Return a handle on the given element. If the element is already a handle, then it will be
-   * returned directly, otherwise a handle of the appropriate class will be constructed.
-   *
-   * @param element the element for which a handle is to be constructed
-   * @return a handle on the given element
-   */
-  static Element forElement(Element element) {
-    if (element is ElementHandle) {
-      return element;
-    }
-    while (true) {
-      if (element.kind == ElementKind.CLASS) {
-        return new ClassElementHandle(element as ClassElement);
-      } else if (element.kind == ElementKind.COMPILATION_UNIT) {
-        return new CompilationUnitElementHandle(
-            element as CompilationUnitElement);
-      } else if (element.kind == ElementKind.CONSTRUCTOR) {
-        return new ConstructorElementHandle(element as ConstructorElement);
-      } else if (element.kind == ElementKind.EXPORT) {
-        return new ExportElementHandle(element as ExportElement);
-      } else if (element.kind == ElementKind.FIELD) {
-        return new FieldElementHandle(element as FieldElement);
-      } else if (element.kind == ElementKind.FUNCTION) {
-        return new FunctionElementHandle(element as FunctionElement);
-      } else if (element.kind == ElementKind.GETTER) {
-        return new PropertyAccessorElementHandle(
-            element as PropertyAccessorElement);
-      } else if (element.kind == ElementKind.IMPORT) {
-        return new ImportElementHandle(element as ImportElement);
-      } else if (element.kind == ElementKind.LABEL) {
-        return new LabelElementHandle(element as LabelElement);
-      } else if (element.kind == ElementKind.LIBRARY) {
-        return new LibraryElementHandle(element as LibraryElement);
-      } else if (element.kind == ElementKind.LOCAL_VARIABLE) {
-        return new LocalVariableElementHandle(element as LocalVariableElement);
-      } else if (element.kind == ElementKind.METHOD) {
-        return new MethodElementHandle(element as MethodElement);
-      } else if (element.kind == ElementKind.PARAMETER) {
-        return new ParameterElementHandle(element as ParameterElement);
-      } else if (element.kind == ElementKind.PREFIX) {
-        return new PrefixElementHandle(element as PrefixElement);
-      } else if (element.kind == ElementKind.SETTER) {
-        return new PropertyAccessorElementHandle(
-            element as PropertyAccessorElement);
-      } else if (element.kind == ElementKind.TOP_LEVEL_VARIABLE) {
-        return new TopLevelVariableElementHandle(
-            element as TopLevelVariableElement);
-      } else if (element.kind == ElementKind.FUNCTION_TYPE_ALIAS) {
-        return new FunctionTypeAliasElementHandle(
-            element as FunctionTypeAliasElement);
-      } else if (element.kind == ElementKind.TYPE_PARAMETER) {
-        return new TypeParameterElementHandle(element as TypeParameterElement);
-      } else {
-        throw new UnsupportedOperationException();
-      }
-      break;
-    }
-  }
-
-  /**
-   * Return an array of the same size as the given array where each element of the returned array is
-   * a handle for the corresponding element of the given array.
-   *
-   * @param elements the elements for which handles are to be created
-   * @return an array of handles to the given elements
-   */
-  static List<Element> forElements(List<Element> elements) {
-    int length = elements.length;
-    List<Element> handles = new List<Element>.from(elements);
-    for (int i = 0; i < length; i++) {
-      handles[i] = forElement(elements[i]);
-    }
-    return handles;
-  }
 }
 
 /**
+ * Interface which allows an [Element] handle to be resynthesized based on an
+ * [ElementLocation].  The concrete classes implementing element handles use
+ * this interface to retrieve the underlying elements when queried.
+ */
+abstract class ElementResynthesizer {
+  final AnalysisContext context;
+
+  ElementResynthesizer(this.context);
+
+  Element getElement(ElementLocation location);
+}
+
+/**
  * The abstract class `ExecutableElementHandle` implements the behavior common to objects that
  * implement a handle to an [ExecutableElement].
  */
 abstract class ExecutableElementHandle extends ElementHandle
     implements ExecutableElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ExecutableElementHandle(ExecutableElement element) : super(element);
+  ExecutableElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ExecutableElement get actualElement =>
       super.actualElement as ExecutableElement;
 
   @override
   List<FunctionElement> get functions => actualElement.functions;
 
   @override
   bool get hasImplicitReturnType => actualElement.hasImplicitReturnType;
@@ skipping 41 matching lines @@
 /**
  * Instances of the class `ExportElementHandle` implement a handle to an `ExportElement`
  * .
  */
 class ExportElementHandle extends ElementHandle implements ExportElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ExportElementHandle(ExportElement element) : super(element);
+  ExportElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ExportElement get actualElement => super.actualElement as ExportElement;
 
   @override
   List<NamespaceCombinator> get combinators => actualElement.combinators;
 
   @override
   LibraryElement get exportedLibrary => actualElement.exportedLibrary;
 
@@ skipping 13 matching lines @@
 /**
  * Instances of the class `FieldElementHandle` implement a handle to a `FieldElement`.
  */
 class FieldElementHandle extends PropertyInducingElementHandle
     implements FieldElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  FieldElementHandle(FieldElement element) : super(element);
+  FieldElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   FieldElement get actualElement => super.actualElement as FieldElement;
 
   @override
   ClassElement get enclosingElement => actualElement.enclosingElement;
 
   @override
   bool get isEnumConstant => actualElement.isEnumConstant;
 
   @override
   ElementKind get kind => ElementKind.FIELD;
 
   @override
   VariableDeclaration computeNode() => actualElement.computeNode();
 }
 
 /**
  * Instances of the class `FunctionElementHandle` implement a handle to a
  * `FunctionElement`.
  */
 class FunctionElementHandle extends ExecutableElementHandle
     implements FunctionElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  FunctionElementHandle(FunctionElement element) : super(element);
+  FunctionElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   FunctionElement get actualElement => super.actualElement as FunctionElement;
 
   @override
   bool get isEntryPoint => actualElement.isEntryPoint;
 
   @override
   ElementKind get kind => ElementKind.FUNCTION;
 
   @override
   SourceRange get visibleRange => actualElement.visibleRange;
 
   @override
   FunctionDeclaration computeNode() => actualElement.computeNode();
 }
 
 /**
  * Instances of the class `FunctionTypeAliasElementHandle` implement a handle to a
  * `FunctionTypeAliasElement`.
  */
 class FunctionTypeAliasElementHandle extends ElementHandle
     implements FunctionTypeAliasElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  FunctionTypeAliasElementHandle(FunctionTypeAliasElement element)
-      : super(element);
+  FunctionTypeAliasElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   FunctionTypeAliasElement get actualElement =>
       super.actualElement as FunctionTypeAliasElement;
 
   @override
   CompilationUnitElement get enclosingElement =>
       super.enclosingElement as CompilationUnitElement;
 
   @override
@@ skipping 18 matching lines @@
 /**
  * Instances of the class `ImportElementHandle` implement a handle to an `ImportElement`
  * .
  */
 class ImportElementHandle extends ElementHandle implements ImportElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ImportElementHandle(ImportElement element) : super(element);
+  ImportElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ImportElement get actualElement => super.actualElement as ImportElement;
 
   @override
   List<NamespaceCombinator> get combinators => actualElement.combinators;
 
   @override
   LibraryElement get importedLibrary => actualElement.importedLibrary;
 
@@ skipping 21 matching lines @@
 
 /**
  * Instances of the class `LabelElementHandle` implement a handle to a `LabelElement`.
  */
 class LabelElementHandle extends ElementHandle implements LabelElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  LabelElementHandle(LabelElement element) : super(element);
+  LabelElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ExecutableElement get enclosingElement =>
       super.enclosingElement as ExecutableElement;
 
   @override
   ElementKind get kind => ElementKind.LABEL;
 }
 
 /**
  * Instances of the class `LibraryElementHandle` implement a handle to a
  * `LibraryElement`.
  */
 class LibraryElementHandle extends ElementHandle implements LibraryElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  LibraryElementHandle(LibraryElement element) : super(element);
+  LibraryElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   LibraryElement get actualElement => super.actualElement as LibraryElement;
 
   @override
   CompilationUnitElement get definingCompilationUnit =>
       actualElement.definingCompilationUnit;
 
   @override
   FunctionElement get entryPoint => actualElement.entryPoint;
 
   @override
   List<LibraryElement> get exportedLibraries => actualElement.exportedLibraries;
 
   @override
   Namespace get exportNamespace => actualElement.exportNamespace;
 
   @override
   List<ExportElement> get exports => actualElement.exports;
 
   @override
   bool get hasExtUri => actualElement.hasExtUri;
 
   @override
   bool get hasLoadLibraryFunction => actualElement.hasLoadLibraryFunction;
 
   @override
+  String get identifier => location.components.last;
+
+  @override
   List<LibraryElement> get importedLibraries => actualElement.importedLibraries;
 
   @override
   List<ImportElement> get imports => actualElement.imports;
 
   @override
   bool get isBrowserApplication => actualElement.isBrowserApplication;
 
   @override
   bool get isDartCore => actualElement.isDartCore;
@@ skipping 37 matching lines @@
  * Instances of the class `LocalVariableElementHandle` implement a handle to a
  * `LocalVariableElement`.
  */
 class LocalVariableElementHandle extends VariableElementHandle
     implements LocalVariableElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  LocalVariableElementHandle(LocalVariableElement element) : super(element);
+  LocalVariableElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   LocalVariableElement get actualElement =>
       super.actualElement as LocalVariableElement;
 
   @override
   ElementKind get kind => ElementKind.LOCAL_VARIABLE;
 
   @override
   SourceRange get visibleRange => actualElement.visibleRange;
 
   @override
   VariableDeclaration computeNode() => actualElement.computeNode();
 }
 
 /**
  * Instances of the class `MethodElementHandle` implement a handle to a `MethodElement`.
  */
 class MethodElementHandle extends ExecutableElementHandle
     implements MethodElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  MethodElementHandle(MethodElement element) : super(element);
+  MethodElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   MethodElement get actualElement => super.actualElement as MethodElement;
 
   @override
   ClassElement get enclosingElement => super.enclosingElement as ClassElement;
 
   @override
   bool get isStatic => actualElement.isStatic;
 
   @override
   ElementKind get kind => ElementKind.METHOD;
 
   @override
   MethodDeclaration computeNode() => actualElement.computeNode();
 }
 
 /**
  * Instances of the class `ParameterElementHandle` implement a handle to a
  * `ParameterElement`.
  */
 class ParameterElementHandle extends VariableElementHandle
     with ParameterElementMixin
     implements ParameterElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  ParameterElementHandle(ParameterElement element) : super(element);
+  ParameterElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ParameterElement get actualElement => super.actualElement as ParameterElement;
 
   @override
   String get defaultValueCode => actualElement.defaultValueCode;
 
   @override
   bool get isInitializingFormal => actualElement.isInitializingFormal;
 
@@ skipping 15 matching lines @@
 
 /**
  * Instances of the class `PrefixElementHandle` implement a handle to a `PrefixElement`.
  */
 class PrefixElementHandle extends ElementHandle implements PrefixElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  PrefixElementHandle(PrefixElement element) : super(element);
+  PrefixElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   PrefixElement get actualElement => super.actualElement as PrefixElement;
 
   @override
   LibraryElement get enclosingElement =>
       super.enclosingElement as LibraryElement;
 
   @override
   List<LibraryElement> get importedLibraries => actualElement.importedLibraries;
 
   @override
   ElementKind get kind => ElementKind.PREFIX;
 }
 
 /**
  * Instances of the class `PropertyAccessorElementHandle` implement a handle to a
  * `PropertyAccessorElement`.
  */
 class PropertyAccessorElementHandle extends ExecutableElementHandle
     implements PropertyAccessorElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  PropertyAccessorElementHandle(PropertyAccessorElement element)
-      : super(element);
+  PropertyAccessorElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   PropertyAccessorElement get actualElement =>
       super.actualElement as PropertyAccessorElement;
 
   @override
   PropertyAccessorElement get correspondingGetter =>
       actualElement.correspondingGetter;
 
   @override
@@ skipping 23 matching lines @@
  * The abstract class `PropertyInducingElementHandle` implements the behavior common to
  * objects that implement a handle to an `PropertyInducingElement`.
  */
 abstract class PropertyInducingElementHandle extends VariableElementHandle
     implements PropertyInducingElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  PropertyInducingElementHandle(PropertyInducingElement element)
-      : super(element);
+  PropertyInducingElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   PropertyInducingElement get actualElement =>
       super.actualElement as PropertyInducingElement;
 
   @override
   PropertyAccessorElement get getter => actualElement.getter;
 
   @override
   DartType get propagatedType => actualElement.propagatedType;
 
   @override
   PropertyAccessorElement get setter => actualElement.setter;
 }
 
 /**
  * Instances of the class `TopLevelVariableElementHandle` implement a handle to a
  * `TopLevelVariableElement`.
  */
 class TopLevelVariableElementHandle extends PropertyInducingElementHandle
     implements TopLevelVariableElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  TopLevelVariableElementHandle(TopLevelVariableElement element)
-      : super(element);
+  TopLevelVariableElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   ElementKind get kind => ElementKind.TOP_LEVEL_VARIABLE;
 }
 
 /**
  * Instances of the class `TypeParameterElementHandle` implement a handle to a
  * [TypeParameterElement].
  */
 class TypeParameterElementHandle extends ElementHandle
     implements TypeParameterElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  TypeParameterElementHandle(TypeParameterElement element) : super(element);
+  TypeParameterElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   TypeParameterElement get actualElement =>
       super.actualElement as TypeParameterElement;
 
   @override
   DartType get bound => actualElement.bound;
 
   @override
   ElementKind get kind => ElementKind.TYPE_PARAMETER;
 
   @override
   TypeParameterType get type => actualElement.type;
 }
 
 /**
  * The abstract class `VariableElementHandle` implements the behavior common to objects that
  * implement a handle to an `VariableElement`.
  */
 abstract class VariableElementHandle extends ElementHandle
     implements VariableElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
-  VariableElementHandle(VariableElement element) : super(element);
+  VariableElementHandle(
+      ElementResynthesizer resynthesizer, ElementLocation location)
+      : super(resynthesizer, location);
 
   @override
   VariableElement get actualElement => super.actualElement as VariableElement;
 
   @override
   DartObject get constantValue => actualElement.constantValue;
 
   @override
   bool get hasImplicitType => actualElement.hasImplicitType;
 
@@ skipping 22 matching lines @@
 }
 
 /**
  * TODO(scheglov) invalid implementation
  */
 class WeakReference<T> {
   final T value;
   WeakReference(this.value);
   T get() => value;
 }