analyzer/lib/src/dart/element/extensions.dart

// Copyright (c) 2020, 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/element.dart';
import 'package:analyzer/src/generated/utilities_dart.dart';
import 'package:collection/collection.dart';
import 'package:meta/meta_meta.dart';

extension ElementAnnotationExtensions on ElementAnnotation {
  static final Map<String, TargetKind> _targetKindsByName = {
    for (final kind in TargetKind.values) kind.name: kind,
  };

  /// Return the target kinds defined for this [ElementAnnotation].
  Set<TargetKind> get targetKinds {
    final element = this.element;
    InterfaceElement? interfaceElement;
    if (element is PropertyAccessorElement) {
      if (element.isGetter) {
        var type = element.returnType;
        if (type is InterfaceType) {
          interfaceElement = type.element;
        }
      }
    } else if (element is ConstructorElement) {
      interfaceElement = element.enclosingElement;
    }
    if (interfaceElement == null) {
      return const <TargetKind>{};
    }
    for (var annotation in interfaceElement.metadata) {
      if (annotation.isTarget) {
        var value = annotation.computeConstantValue();
        if (value == null) {
          return const <TargetKind>{};
        }

        var annotationKinds = value.getField('kinds')?.toSetValue();
        if (annotationKinds == null) {
          return const <TargetKind>{};
        }

        return annotationKinds
            .map((e) => e.getField('_name')?.toStringValue())
            .map((name) => _targetKindsByName[name])
            .whereNotNull()
            .toSet();
      }
    }
    return const <TargetKind>{};
  }
}

extension ElementExtension on Element {
  /// Return `true` if this element, the enclosing class (if there is one), or
  /// the enclosing library, has been annotated with the `@doNotStore`
  /// annotation.
  bool get hasOrInheritsDoNotStore {
    if (hasDoNotStore) {
      return true;
    }

    var ancestor = enclosingElement;
    if (ancestor is InterfaceElement) {
      if (ancestor.hasDoNotStore) {
        return true;
      }
      ancestor = ancestor.enclosingElement;
    } else if (ancestor is ExtensionElement) {
      if (ancestor.hasDoNotStore) {
        return true;
      }
      ancestor = ancestor.enclosingElement;
    }

    return ancestor is CompilationUnitElement &&
        ancestor.enclosingElement.hasDoNotStore;
  }

  /// Return `true` if this element is an instance member of a class or mixin.
  ///
  /// Only [MethodElement]s and [PropertyAccessorElement]s are supported.
  /// We intentionally exclude [ConstructorElement]s - they can only be
  /// invoked in instance creation expressions, and [FieldElement]s - they
  /// cannot be invoked directly and are always accessed using corresponding
  /// [PropertyAccessorElement]s.
  bool get isInstanceMember {
    assert(this is! PropertyInducingElement,
        'Check the PropertyAccessorElement instead');
    var this_ = this;
    var enclosing = this_.enclosingElement;
    if (enclosing is InterfaceElement) {
      return this_ is MethodElement && !this_.isStatic ||
          this_ is PropertyAccessorElement && !this_.isStatic;
    }
    return false;
  }
}

extension ExecutableElementExtension on ExecutableElement {
  bool get isEnumConstructor {
    return this is ConstructorElement && enclosingElement is EnumElementImpl;
  }
}

extension ExecutableElementExtensionQuestion on ExecutableElement? {
  DartType? get firstParameterType {
    final self = this;
    if (self is MethodElement) {
      return self.parameters.firstOrNull?.type;
    }
    return null;
  }
}

extension ParameterElementExtensions on ParameterElement {
  /// Return [ParameterElement] with the specified properties replaced.
  ParameterElement copyWith({
    DartType? type,
    ParameterKind? kind,
    bool? isCovariant,
  }) {
    return ParameterElementImpl.synthetic(
      name,
      type ?? this.type,
      // ignore: deprecated_member_use_from_same_package
      kind ?? parameterKind,
    )..isExplicitlyCovariant = isCovariant ?? this.isCovariant;
  }
}

extension RecordTypeExtension on RecordType {
  /// A regular expression used to match positional field names.
  static final RegExp _positionalName = RegExp(r'^\$[1-9]\d*$');

  List<RecordTypeField> get fields {
    return [
      ...positionalFields,
      ...namedFields,
    ];
  }

  /// The [name] is either an actual name like `foo` in `({int foo})`, or
  /// the name of a positional field like `$1` in `(int, String)`.
  RecordTypeField? fieldByName(String name) {
    return namedField(name) ?? positionalField(name);
  }

  RecordTypeNamedField? namedField(String name) {
    for (final field in namedFields) {
      if (field.name == name) {
        return field;
      }
    }
    return null;
  }

  RecordTypePositionalField? positionalField(String name) {
    final index = positionalFieldIndex(name);
    if (index != null && index < positionalFields.length) {
      return positionalFields[index];
    }
    return null;
  }

  /// Attempt to parse `$1`, `$2`, etc.
  static int? positionalFieldIndex(String name) {
    if (_positionalName.hasMatch(name)) {
      final positionString = name.substring(1);
      // Use `tryParse` instead of `parse`
      // even though the numeral matches the pattern `[1-9]\d*`,
      // to reject numerals too big to fit in an `int`.
      final position = int.tryParse(positionString);
      if (position != null) return position - 1;
    }
    return null;
  }
}