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start on json serializable macro
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3 files changed

+153
-2
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3 files changed

+153
-2
lines changed

‎working/macros/example/bin/run.dart

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,8 @@ void main() async {
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var dataClassUri = Uri.parse('package:macro_proposal/data_class.dart');
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var observableUri = Uri.parse('package:macro_proposal/observable.dart');
2323
var autoDisposableUri = Uri.parse('package:macro_proposal/auto_dispose.dart');
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var jsonSerializableUri =
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Uri.parse('package:macro_proposal/json_serializable.dart');
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var bootstrapContent = bootstrapMacroIsolate({
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dataClassUri.toString(): {
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'AutoConstructor': [''],
@@ -35,6 +37,9 @@ void main() async {
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autoDisposableUri.toString(): {
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'AutoDispose': [''],
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},
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jsonSerializableUri.toString(): {
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'JsonSerializable': [''],
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}
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}, SerializationMode.byteDataClient);
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bootstrapFile.writeAsStringSync(bootstrapContent);
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var bootstrapKernelFile =
@@ -95,6 +100,8 @@ void main() async {
95100
'$observableUri;${bootstrapKernelFile.path}',
96101
'--precompiled-macro',
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'$autoDisposableUri;${bootstrapKernelFile.path}',
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'--precompiled-macro',
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'$jsonSerializableUri;${bootstrapKernelFile.path}',
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'--macro-serialization-mode=bytedata',
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'--input-linked',
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bootstrapKernelFile.path,

‎working/macros/example/bin/user_main.dart

Lines changed: 25 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,11 +7,16 @@ import 'dart:math';
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import 'package:macro_proposal/auto_dispose.dart';
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import 'package:macro_proposal/data_class.dart';
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import 'package:macro_proposal/observable.dart';
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import 'package:macro_proposal/json_serializable.dart';
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void main() {
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var rand = Random();
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var roger =
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User.gen(age: rand.nextInt(100), name: 'Roger', username: 'roger1337');
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var rogerJson = {
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'age': rand.nextInt(100),
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'name': 'Roger',
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'username': 'roger1337'
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};
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var roger = User.fromJson(rogerJson);
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print(roger);
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var joe = Manager.gen(
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age: rand.nextInt(100),
@@ -31,9 +36,18 @@ void main() {
3136

3237
var state = MyState.gen(a: ADisposable(), b: BDisposable(), c: 'hello world');
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state.dispose();
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var father = Father.fromJson({
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'age': roger.age + 25,
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'name': 'Rogers Dad',
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'username': 'dadJokesAreCool123',
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'child': rogerJson,
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});
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print(father);
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}
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3649
@DataClass()
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@JsonSerializable()
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class User {
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final int age;
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final String name;
@@ -87,3 +101,12 @@ class BDisposable implements Disposable {
87101
print('disposing of BDisposable');
88102
}
89103
}
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@DataClass()
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@JsonSerializable()
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class Father implements User {
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final int age;
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final String name;
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final String username;
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final User child;
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}

‎working/macros/example/lib/json_serializable.dart

Lines changed: 121 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,121 @@
1+
// Copyright (c) 2022, 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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//
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// ignore_for_file: deprecated_member_use
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// There is no public API exposed yet, the in progress api lives here.
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import 'package:_fe_analyzer_shared/src/macros/api.dart';
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final dartCore = Uri.parse('dart:core');
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// TODO: Support `toJson`, collections, and probably some other things :).
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macro class JsonSerializable
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implements ClassDeclarationsMacro, ClassDefinitionMacro {
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const JsonSerializable();
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@override
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Future<void> buildDeclarationsForClass(
19+
ClassDeclaration clazz, ClassMemberDeclarationBuilder builder) async {
20+
var constructors = await builder.constructorsOf(clazz);
21+
if (constructors.any((c) => c.identifier.name == 'fromJson')) {
22+
throw ArgumentError('There is already a `fromJson` constructor for '
23+
'`${clazz.identifier.name}`, so one could not be added.');
24+
}
25+
26+
var map = await builder.resolveIdentifier(dartCore, 'Map');
27+
var string = NamedTypeAnnotationCode(
28+
name: await builder.resolveIdentifier(dartCore, 'String'));
29+
var dynamic = NamedTypeAnnotationCode(
30+
name: await builder.resolveIdentifier(dartCore, 'dynamic'));
31+
var mapStringDynamic =
32+
NamedTypeAnnotationCode(name: map, typeArguments: [string, dynamic]);
33+
builder.declareInClass(DeclarationCode.fromParts([
34+
'external ',
35+
clazz.identifier.name,
36+
'.fromJson(',
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mapStringDynamic,
38+
' json);',
39+
]));
40+
}
41+
42+
@override
43+
Future<void> buildDefinitionForClass(
44+
ClassDeclaration clazz, ClassDefinitionBuilder builder) async {
45+
// TODO: support extending other classes.
46+
if (clazz.superclass != null) {
47+
throw UnsupportedError(
48+
'Serialization of classes that extend other classes is not supported.');
49+
}
50+
51+
var constructors = await builder.constructorsOf(clazz);
52+
var fromJson =
53+
constructors.firstWhere((c) => c.identifier.name == 'fromJson');
54+
var fromJsonBuilder = await builder.buildConstructor(fromJson.identifier);
55+
var fields = await builder.fieldsOf(clazz);
56+
var jsonParam = fromJson.positionalParameters.single.identifier;
57+
fromJsonBuilder.augment(initializers: [
58+
for (var field in fields)
59+
Code.fromParts([
60+
field.identifier,
61+
' = ',
62+
await _convertField(field, jsonParam, builder),
63+
]),
64+
]);
65+
}
66+
67+
// TODO: Support nested List, Map, etc conversion, including deep casting.
68+
Future<Code> _convertField(FieldDeclaration field, Identifier jsonParam,
69+
DefinitionBuilder builder) async {
70+
var fieldType = field.type;
71+
if (fieldType is! NamedTypeAnnotation) {
72+
throw ArgumentError(
73+
'Only fields with named types are allowed on serializable classes, '
74+
'but `${field.identifier.name}` was not a named type.');
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}
76+
var fieldTypeDecl = await builder.declarationOf(fieldType.identifier);
77+
while (fieldTypeDecl is TypeAliasDeclaration) {
78+
var aliasedType = fieldTypeDecl.aliasedType;
79+
if (aliasedType is! NamedTypeAnnotation) {
80+
throw ArgumentError(
81+
'Only fields with named types are allowed on serializable classes, '
82+
'but `${field.identifier.name}` did not resolve to a named type.');
83+
}
84+
}
85+
if (fieldTypeDecl is! ClassDeclaration) {
86+
throw ArgumentError(
87+
'Only classes are supported in field types for serializable classes, '
88+
'but the field `${field.identifier.name}` does not have a class '
89+
'type.');
90+
}
91+
92+
var fieldConstructors = await builder.constructorsOf(fieldTypeDecl);
93+
var fieldTypeFromJson = fieldConstructors
94+
.firstWhereOrNull((c) => c.identifier.name == 'fromJson')
95+
?.identifier;
96+
if (fieldTypeFromJson != null) {
97+
return Code.fromParts([
98+
fieldTypeFromJson,
99+
'(',
100+
jsonParam,
101+
'["${field.identifier.name}"])',
102+
]);
103+
} else {
104+
return Code.fromParts([
105+
jsonParam,
106+
// TODO: support nested serializable types.
107+
'["${field.identifier.name}"] as ',
108+
field.type.code,
109+
]);
110+
}
111+
}
112+
}
113+
114+
extension _FirstWhereOrNull<T> on Iterable<T> {
115+
T? firstWhereOrNull(bool Function(T) compare) {
116+
for (var item in this) {
117+
if (compare(item)) return item;
118+
}
119+
return null;
120+
}
121+
}

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