| // Copyright (c) 2019, 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. |
| |
| import 'package:analyzer/dart/element/element.dart'; |
| import 'package:analyzer/dart/element/type.dart'; |
| import 'package:analyzer/src/dart/element/type.dart'; |
| import 'package:analyzer_plugin/protocol/protocol_common.dart' show SourceEdit; |
| import 'package:nnbd_migration/src/nullability_node.dart'; |
| import 'package:nnbd_migration/src/potential_modification.dart'; |
| |
| /// Representation of a type in the code to be migrated. In addition to |
| /// tracking the (unmigrated) [DartType], we track the [ConstraintVariable]s |
| /// indicating whether the type, and the types that compose it, are nullable. |
| class DecoratedType { |
| final DartType type; |
| |
| final NullabilityNode node; |
| |
| /// If `this` is a function type, the [DecoratedType] of its return type. |
| final DecoratedType returnType; |
| |
| /// If `this` is a function type, the [DecoratedType] of each of its |
| /// positional parameters (including both required and optional positional |
| /// parameters). |
| final List<DecoratedType> positionalParameters; |
| |
| /// If `this` is a function type, the [DecoratedType] of each of its named |
| /// parameters. |
| final Map<String, DecoratedType> namedParameters; |
| |
| /// If `this` is a parameterized type, the [DecoratedType] of each of its |
| /// type parameters. |
| /// |
| /// TODO(paulberry): how should we handle generic typedefs? |
| final List<DecoratedType> typeArguments; |
| |
| DecoratedType(this.type, this.node, |
| {this.returnType, |
| this.positionalParameters = const [], |
| this.namedParameters = const {}, |
| this.typeArguments = const []}) { |
| assert(node != null); |
| } |
| |
| /// Creates a [DecoratedType] corresponding to the given [element], which is |
| /// presumed to have come from code that is already migrated. |
| factory DecoratedType.forElement(Element element, NullabilityGraph graph) { |
| DecoratedType decorate(DartType type) { |
| assert((type as TypeImpl).nullabilitySuffix == |
| NullabilitySuffix.star); // TODO(paulberry) |
| if (type is FunctionType) { |
| var positionalParameters = <DecoratedType>[]; |
| for (var parameter in type.parameters) { |
| assert(parameter.isPositional); // TODO(paulberry) |
| positionalParameters.add(decorate(parameter.type)); |
| } |
| return DecoratedType(type, graph.never, |
| returnType: decorate(type.returnType), |
| positionalParameters: positionalParameters); |
| } else if (type is InterfaceType) { |
| assert(type.typeParameters.isEmpty); // TODO(paulberry) |
| return DecoratedType(type, graph.never); |
| } else { |
| throw type.runtimeType; // TODO(paulberry) |
| } |
| } |
| |
| DecoratedType decoratedType; |
| if (element is MethodElement) { |
| decoratedType = decorate(element.type); |
| } else if (element is PropertyAccessorElement) { |
| decoratedType = decorate(element.type); |
| } else if (element is ConstructorElement) { |
| decoratedType = decorate(element.type); |
| } else { |
| throw element.runtimeType; // TODO(paulberry) |
| } |
| return decoratedType; |
| } |
| |
| /// Apply the given [substitution] to this type. |
| /// |
| /// [undecoratedResult] is the result of the substitution, as determined by |
| /// the normal type system. |
| DecoratedType substitute( |
| Map<TypeParameterElement, DecoratedType> substitution, |
| DartType undecoratedResult) { |
| if (substitution.isEmpty) return this; |
| return _substitute(substitution, undecoratedResult); |
| } |
| |
| @override |
| String toString() { |
| var trailing = node.debugSuffix; |
| var type = this.type; |
| if (type is TypeParameterType || type is VoidType) { |
| return '$type$trailing'; |
| } else if (type is InterfaceType) { |
| var name = type.element.name; |
| var args = ''; |
| if (type.typeArguments.isNotEmpty) { |
| args = '<${type.typeArguments.join(', ')}>'; |
| } |
| return '$name$args$trailing'; |
| } else if (type is FunctionType) { |
| assert(type.typeFormals.isEmpty); // TODO(paulberry) |
| assert(type.namedParameterTypes.isEmpty && |
| namedParameters.isEmpty); // TODO(paulberry) |
| var args = positionalParameters.map((p) => p.toString()).join(', '); |
| return '$returnType Function($args)$trailing'; |
| } else if (type is DynamicTypeImpl) { |
| return 'dynamic'; |
| } else { |
| throw '$type'; // TODO(paulberry) |
| } |
| } |
| |
| /// Creates a shallow copy of `this`, replacing the nullability node. |
| DecoratedType withNode(NullabilityNode node) => DecoratedType(type, node, |
| returnType: returnType, |
| positionalParameters: positionalParameters, |
| namedParameters: namedParameters, |
| typeArguments: typeArguments); |
| |
| /// Internal implementation of [_substitute], used as a recursion target. |
| DecoratedType _substitute( |
| Map<TypeParameterElement, DecoratedType> substitution, |
| DartType undecoratedResult) { |
| var type = this.type; |
| if (type is FunctionType && undecoratedResult is FunctionType) { |
| assert(type.typeFormals.isEmpty); // TODO(paulberry) |
| var newPositionalParameters = <DecoratedType>[]; |
| for (int i = 0; i < positionalParameters.length; i++) { |
| var numRequiredParameters = |
| undecoratedResult.normalParameterTypes.length; |
| var undecoratedParameterType = i < numRequiredParameters |
| ? undecoratedResult.normalParameterTypes[i] |
| : undecoratedResult |
| .optionalParameterTypes[i - numRequiredParameters]; |
| newPositionalParameters.add(positionalParameters[i] |
| ._substitute(substitution, undecoratedParameterType)); |
| } |
| return DecoratedType(undecoratedResult, node, |
| returnType: returnType._substitute( |
| substitution, undecoratedResult.returnType), |
| positionalParameters: newPositionalParameters); |
| } else if (type is TypeParameterType) { |
| var inner = substitution[type.element]; |
| return DecoratedType(undecoratedResult, |
| NullabilityNode.forSubstitution(inner?.node, node)); |
| } else if (type is VoidType) { |
| return this; |
| } |
| throw '$type.substitute($substitution)'; // TODO(paulberry) |
| } |
| } |
| |
| /// A [DecoratedType] based on a type annotation appearing explicitly in the |
| /// source code. |
| /// |
| /// This class implements [PotentialModification] because it knows how to update |
| /// the source code to reflect its nullability. |
| class DecoratedTypeAnnotation extends DecoratedType |
| implements PotentialModification { |
| final int _offset; |
| |
| DecoratedTypeAnnotation( |
| DartType type, NullabilityNode nullabilityNode, this._offset, |
| {List<DecoratedType> typeArguments = const [], |
| DecoratedType returnType, |
| List<DecoratedType> positionalParameters = const [], |
| Map<String, DecoratedType> namedParameters = const {}}) |
| : super(type, nullabilityNode, |
| typeArguments: typeArguments, |
| returnType: returnType, |
| positionalParameters: positionalParameters, |
| namedParameters: namedParameters); |
| |
| @override |
| bool get isEmpty => !node.isNullable; |
| |
| @override |
| Iterable<SourceEdit> get modifications => |
| isEmpty ? [] : [SourceEdit(_offset, 0, '?')]; |
| } |