| // 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 services.completion.contributor.dart.type_member; |
| |
| import 'dart:async'; |
| import 'dart:collection'; |
| |
| import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart'; |
| import 'package:analysis_server/src/services/completion/dart/local_declaration_visitor.dart'; |
| import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart'; |
| import 'package:analyzer/dart/element/element.dart'; |
| import 'package:analyzer/dart/element/type.dart'; |
| import 'package:analyzer/src/generated/ast.dart'; |
| |
| import '../../../protocol_server.dart' |
| show CompletionSuggestion, CompletionSuggestionKind; |
| |
| /** |
| * A contributor for calculating instance invocation / access suggestions |
| * `completion.getSuggestions` request results. |
| */ |
| class TypeMemberContributor extends DartCompletionContributor { |
| @override |
| Future<List<CompletionSuggestion>> computeSuggestions( |
| DartCompletionRequest request) async { |
| // Determine if the target looks like a prefixed identifier, |
| // a method invocation, or a property access |
| Expression parsedExpression = request.dotTarget; |
| if (parsedExpression == null) { |
| return EMPTY_LIST; |
| } |
| |
| // Resolve the expression and the containing library |
| await request.resolveExpression(parsedExpression); |
| LibraryElement containingLibrary = request.libraryElement; |
| // Gracefully degrade if the library element could not be resolved |
| // e.g. detached part file or source change |
| if (containingLibrary == null) { |
| return EMPTY_LIST; |
| } |
| |
| // Recompute the target since resolution may have changed it |
| Expression expression = request.dotTarget; |
| if (expression == null || expression.isSynthetic) { |
| return EMPTY_LIST; |
| } |
| if (expression is Identifier) { |
| Element elem = expression.bestElement; |
| if (elem is ClassElement) { |
| // Suggestions provided by StaticMemberContributor |
| return EMPTY_LIST; |
| } |
| if (elem is PrefixElement) { |
| // Suggestions provided by LibraryMemberContributor |
| return EMPTY_LIST; |
| } |
| } |
| |
| // Determine the target expression's type |
| DartType type = expression.bestType; |
| if (type.isDynamic) { |
| // If the expression does not provide a good type |
| // then attempt to get a better type from the element |
| if (expression is Identifier) { |
| Element elem = expression.bestElement; |
| if (elem is FunctionTypedElement) { |
| type = elem.returnType; |
| } else if (elem is ParameterElement) { |
| type = elem.type; |
| } else if (elem is LocalVariableElement) { |
| type = elem.type; |
| } |
| if ((type == null || type.isDynamic) && |
| expression is SimpleIdentifier) { |
| // If the element does not provide a good type |
| // then attempt to get a better type from a local declaration |
| _LocalBestTypeVisitor visitor = |
| new _LocalBestTypeVisitor(expression.name, request.offset); |
| if (visitor.visit(expression) && visitor.typeFound != null) { |
| type = visitor.typeFound; |
| } |
| } |
| } |
| } |
| String containingMethodName; |
| if (expression is SuperExpression && type is InterfaceType) { |
| // Suggest members from superclass if target is "super" |
| type = (type as InterfaceType).superclass; |
| // Determine the name of the containing method because |
| // the most likely completion is a super expression with same name |
| MethodDeclaration containingMethod = |
| expression.getAncestor((p) => p is MethodDeclaration); |
| if (containingMethod != null) { |
| SimpleIdentifier id = containingMethod.name; |
| if (id != null) { |
| containingMethodName = id.name; |
| } |
| } |
| } |
| if (type.isDynamic) { |
| // Suggest members from object if target is "dynamic" |
| type = request.objectType; |
| } |
| |
| // Build the suggestions |
| if (type is InterfaceType) { |
| _SuggestionBuilder builder = new _SuggestionBuilder(containingLibrary); |
| builder.buildSuggestions(type, containingMethodName); |
| return builder.suggestions.toList(); |
| } |
| return EMPTY_LIST; |
| } |
| } |
| |
| /** |
| * An [AstVisitor] which looks for a declaration with the given name |
| * and if found, tries to determine a type for that declaration. |
| */ |
| class _LocalBestTypeVisitor extends LocalDeclarationVisitor { |
| /** |
| * The name for the declaration to be found. |
| */ |
| final String targetName; |
| |
| /** |
| * The best type for the found declaration, |
| * or `null` if no declaration found or failed to determine a type. |
| */ |
| DartType typeFound; |
| |
| /** |
| * Construct a new instance to search for a declaration |
| */ |
| _LocalBestTypeVisitor(this.targetName, int offset) : super(offset); |
| |
| @override |
| void declaredClass(ClassDeclaration declaration) { |
| if (declaration.name.name == targetName) { |
| // no type |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredClassTypeAlias(ClassTypeAlias declaration) { |
| if (declaration.name.name == targetName) { |
| // no type |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredField(FieldDeclaration fieldDecl, VariableDeclaration varDecl) { |
| if (varDecl.name.name == targetName) { |
| // Type provided by the element in computeFull above |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredFunction(FunctionDeclaration declaration) { |
| if (declaration.name.name == targetName) { |
| TypeName typeName = declaration.returnType; |
| if (typeName != null) { |
| typeFound = typeName.type; |
| } |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredFunctionTypeAlias(FunctionTypeAlias declaration) { |
| if (declaration.name.name == targetName) { |
| TypeName typeName = declaration.returnType; |
| if (typeName != null) { |
| typeFound = typeName.type; |
| } |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredLabel(Label label, bool isCaseLabel) { |
| if (label.label.name == targetName) { |
| // no type |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredLocalVar(SimpleIdentifier name, TypeName type) { |
| if (name.name == targetName) { |
| typeFound = name.bestType; |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredMethod(MethodDeclaration declaration) { |
| if (declaration.name.name == targetName) { |
| TypeName typeName = declaration.returnType; |
| if (typeName != null) { |
| typeFound = typeName.type; |
| } |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredParam(SimpleIdentifier name, TypeName type) { |
| if (name.name == targetName) { |
| // Type provided by the element in computeFull above |
| finished(); |
| } |
| } |
| |
| @override |
| void declaredTopLevelVar( |
| VariableDeclarationList varList, VariableDeclaration varDecl) { |
| if (varDecl.name.name == targetName) { |
| // Type provided by the element in computeFull above |
| finished(); |
| } |
| } |
| } |
| |
| /** |
| * This class provides suggestions based upon the visible instance members in |
| * an interface type. |
| */ |
| class _SuggestionBuilder { |
| /** |
| * Enumerated value indicating that we have not generated any completions for |
| * a given identifier yet. |
| */ |
| static const int _COMPLETION_TYPE_NONE = 0; |
| |
| /** |
| * Enumerated value indicating that we have generated a completion for a |
| * getter. |
| */ |
| static const int _COMPLETION_TYPE_GETTER = 1; |
| |
| /** |
| * Enumerated value indicating that we have generated a completion for a |
| * setter. |
| */ |
| static const int _COMPLETION_TYPE_SETTER = 2; |
| |
| /** |
| * Enumerated value indicating that we have generated a completion for a |
| * field, a method, or a getter/setter pair. |
| */ |
| static const int _COMPLETION_TYPE_FIELD_OR_METHOD_OR_GETSET = 3; |
| |
| /** |
| * The library containing the unit in which the completion is requested. |
| */ |
| final LibraryElement containingLibrary; |
| |
| /** |
| * Map indicating, for each possible completion identifier, whether we have |
| * already generated completions for a getter, setter, or both. The "both" |
| * case also handles the case where have generated a completion for a method |
| * or a field. |
| * |
| * Note: the enumerated values stored in this map are intended to be bitwise |
| * compared. |
| */ |
| Map<String, int> _completionTypesGenerated = new HashMap<String, int>(); |
| |
| /** |
| * Map from completion identifier to completion suggestion |
| */ |
| Map<String, CompletionSuggestion> _suggestionMap = |
| <String, CompletionSuggestion>{}; |
| |
| _SuggestionBuilder(this.containingLibrary); |
| |
| Iterable<CompletionSuggestion> get suggestions => _suggestionMap.values; |
| |
| /** |
| * Return completion suggestions for 'dot' completions on the given [type]. |
| * If the 'dot' completion is a super expression, then [containingMethodName] |
| * is the name of the method in which the completion is requested. |
| */ |
| void buildSuggestions(InterfaceType type, String containingMethodName) { |
| // Visit all of the types in the class hierarchy, collecting possible |
| // completions. If multiple elements are found that complete to the same |
| // identifier, addSuggestion will discard all but the first (with a few |
| // exceptions to handle getter/setter pairs). |
| List<InterfaceType> types = _getTypeOrdering(type); |
| for (InterfaceType targetType in types) { |
| for (MethodElement method in targetType.methods) { |
| // Exclude static methods when completion on an instance |
| if (!method.isStatic) { |
| // Boost the relevance of a super expression |
| // calling a method of the same name as the containing method |
| _addSuggestion(method, |
| relevance: method.name == containingMethodName |
| ? DART_RELEVANCE_HIGH |
| : DART_RELEVANCE_DEFAULT); |
| } |
| } |
| for (PropertyAccessorElement propertyAccessor in targetType.accessors) { |
| if (!propertyAccessor.isStatic) { |
| if (propertyAccessor.isSynthetic) { |
| // Avoid visiting a field twice |
| if (propertyAccessor.isGetter) { |
| _addSuggestion(propertyAccessor.variable); |
| } |
| } else { |
| _addSuggestion(propertyAccessor); |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Add a suggestion based upon the given element, provided that it is not |
| * shadowed by a previously added suggestion. |
| */ |
| void _addSuggestion(Element element, |
| {int relevance: DART_RELEVANCE_DEFAULT}) { |
| if (element.isPrivate) { |
| if (element.library != containingLibrary) { |
| // Do not suggest private members for imported libraries |
| return; |
| } |
| } |
| String identifier = element.displayName; |
| int alreadyGenerated = _completionTypesGenerated.putIfAbsent( |
| identifier, () => _COMPLETION_TYPE_NONE); |
| if (element is MethodElement) { |
| // Anything shadows a method. |
| if (alreadyGenerated != _COMPLETION_TYPE_NONE) { |
| return; |
| } |
| _completionTypesGenerated[identifier] = |
| _COMPLETION_TYPE_FIELD_OR_METHOD_OR_GETSET; |
| } else if (element is PropertyAccessorElement) { |
| if (element.isGetter) { |
| // Getters, fields, and methods shadow a getter. |
| if ((alreadyGenerated & _COMPLETION_TYPE_GETTER) != 0) { |
| return; |
| } |
| _completionTypesGenerated[identifier] |= _COMPLETION_TYPE_GETTER; |
| } else { |
| // Setters, fields, and methods shadow a setter. |
| if ((alreadyGenerated & _COMPLETION_TYPE_SETTER) != 0) { |
| return; |
| } |
| _completionTypesGenerated[identifier] |= _COMPLETION_TYPE_SETTER; |
| } |
| } else if (element is FieldElement) { |
| // Fields and methods shadow a field. A getter/setter pair shadows a |
| // field, but a getter or setter by itself doesn't. |
| if (alreadyGenerated == _COMPLETION_TYPE_FIELD_OR_METHOD_OR_GETSET) { |
| return; |
| } |
| _completionTypesGenerated[identifier] = |
| _COMPLETION_TYPE_FIELD_OR_METHOD_OR_GETSET; |
| } else { |
| // Unexpected element type; skip it. |
| assert(false); |
| return; |
| } |
| CompletionSuggestion suggestion = |
| createSuggestion(element, relevance: relevance); |
| if (suggestion != null) { |
| _suggestionMap[suggestion.completion] = suggestion; |
| } |
| } |
| |
| /** |
| * Get a list of [InterfaceType]s that should be searched to find the |
| * possible completions for an object having type [type]. |
| */ |
| List<InterfaceType> _getTypeOrdering(InterfaceType type) { |
| // Candidate completions can come from [type] as well as any types above it |
| // in the class hierarchy (including mixins, superclasses, and interfaces). |
| // If a given completion identifier shows up in multiple types, we should |
| // use the element that is nearest in the superclass chain, so we will |
| // visit [type] first, then its mixins, then its superclass, then its |
| // superclass's mixins, etc., and only afterwards visit interfaces. |
| // |
| // We short-circuit loops in the class hierarchy by keeping track of the |
| // classes seen (not the interfaces) so that we won't be fooled by nonsense |
| // like "class C<T> extends C<List<T>> {}" |
| List<InterfaceType> result = <InterfaceType>[]; |
| Set<ClassElement> classesSeen = new HashSet<ClassElement>(); |
| List<InterfaceType> typesToVisit = <InterfaceType>[type]; |
| while (typesToVisit.isNotEmpty) { |
| InterfaceType nextType = typesToVisit.removeLast(); |
| if (!classesSeen.add(nextType.element)) { |
| // Class had already been seen, so ignore this type. |
| continue; |
| } |
| result.add(nextType); |
| // typesToVisit is a stack, so push on the interfaces first, then the |
| // superclass, then the mixins. This will ensure that they are visited |
| // in the reverse order. |
| typesToVisit.addAll(nextType.interfaces); |
| if (nextType.superclass != null) { |
| typesToVisit.add(nextType.superclass); |
| } |
| typesToVisit.addAll(nextType.mixins); |
| } |
| return result; |
| } |
| } |