// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'package:analyzer/dart/element/element.dart';
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import 'package:analyzer/dart/element/type.dart';
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import 'package:json_annotation/json_annotation.dart';
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/// Context information provided in calls to [TypeHelper.serialize] and
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/// [TypeHelper.deserialize].
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abstract class TypeHelperContext {
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/// The annotated class that code is being generated for.
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ClassElement get classElement;
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/// The field that code is being generated for.
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FieldElement get fieldElement;
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/// Returns `true` if [fieldElement] could potentially contain a `null` value.
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bool get nullable;
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/// [expression] may be just the name of the field or it may an expression
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/// representing the serialization of a value.
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Object serialize(DartType fieldType, String expression);
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/// [expression] may be just the name of the field or it may an expression
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/// representing the serialization of a value.
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Object deserialize(DartType fieldType, String expression);
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/// Adds [memberContent] to the set of generated, top-level members.
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void addMember(String memberContent);
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}
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/// Extended context information with includes configuration values
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/// corresponding to `JsonSerializableGenerator` settings.
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abstract class TypeHelperContextWithConfig extends TypeHelperContext {
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JsonSerializable get config;
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}
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abstract class TypeHelper<T extends TypeHelperContext> {
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const TypeHelper();
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/// Returns Dart code that serializes an [expression] representing a Dart
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/// object of type [targetType].
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///
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/// If [targetType] is not supported, returns `null`.
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///
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/// Let's say you want to serialize a class `Foo` as just its `id` property
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/// of type `int`.
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///
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/// Treating [expression] as a opaque Dart expression, the [serialize]
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/// implementation could be a simple as:
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///
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/// ```dart
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/// String serialize(DartType targetType, String expression) =>
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/// "$expression.id";
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/// ```.
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Object serialize(DartType targetType, String expression, T context);
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/// Returns Dart code that deserializes an [expression] representing a JSON
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/// literal to into [targetType].
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///
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/// If [targetType] is not supported, returns `null`.
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///
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/// Let's say you want to deserialize a class `Foo` by taking an `int` stored
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/// in a JSON literal and calling the `Foo.fromInt` constructor.
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///
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/// Treating [expression] as a opaque Dart expression representing a JSON
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/// literal, the [deserialize] implementation could be a simple as:
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///
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/// ```dart
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/// String deserialize(DartType targetType, String expression) =>
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/// "new Foo.fromInt($expression)";
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/// ```.
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///
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/// Note that [targetType] is not used here. If you wanted to support many
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/// types of [targetType] you could write:
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///
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/// ```dart
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/// String deserialize(DartType targetType, String expression) =>
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/// "new ${targetType.name}.fromInt($expression)";
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/// ```.
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Object deserialize(DartType targetType, String expression, T context);
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}
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class LambdaResult {
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final String expression;
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final String lambda;
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LambdaResult(this.expression, this.lambda);
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@override
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String toString() => '$lambda($expression)';
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static String process(Object subField, String closureArg) =>
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(subField is LambdaResult && closureArg == subField.expression)
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? subField.lambda
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: '($closureArg) => $subField';
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}
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class UnsupportedTypeError extends Error {
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final String expression;
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final DartType type;
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final String reason;
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UnsupportedTypeError(this.type, this.expression, this.reason);
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}
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Object commonNullPrefix(
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bool nullable, String expression, Object unsafeExpression) =>
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nullable
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? '$expression == null ? null : $unsafeExpression'
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: unsafeExpression;
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