Make proto3_json.dart aware of well known types

protobuf/CHANGELOG.md

@@ -1,3 +1,5 @@
+## 5.0.0-wip
+
 ## 4.2.0
 
 * Internal refactoring to split the package into libraries. This allows
@@ -11,6 +13,9 @@
 * Improve performance of `GeneratedMessage` members: `writeToJsonMap`,
   `writeToJson`, `mergeFromJson`, `mergeFromJsonMap`. ([#1028])
 
+* Remove `BuilderInfo.fromProto3Json` and `BuilderInfo.toProto3Json` as a part
+  of an internal refactoring.
+
 [#1026]: https://github.com/google/protobuf.dart/pull/1026
 [#1027]: https://github.com/google/protobuf.dart/pull/1027
 [#1028]: https://github.com/google/protobuf.dart/pull/1028

protobuf/lib/protobuf.dart

@@ -18,4 +18,6 @@ export 'src/protobuf/internal.dart'
         GeneratedMessageInternalExtension,
         MapFieldInfoInternalExtension,
         mapKeyFieldNumber,
-        mapValueFieldNumber;
+        mapValueFieldNumber,
+        mergeFromProto3JsonAny,
+        writeToProto3JsonAny;

protobuf/lib/src/protobuf/builder_info.dart

@@ -42,24 +42,17 @@ class BuilderInfo {
   List<FieldInfo>? _sortedByTag;
 
   // For well-known types.
-  final Object? Function(GeneratedMessage message, TypeRegistry typeRegistry)?
-  toProto3Json;
-  final Function(
-    GeneratedMessage targetMessage,
-    Object json,
-    TypeRegistry typeRegistry,
-    JsonParsingContext context,
-  )?
-  fromProto3Json;
+  final WellKnownType? _wellKnownType;
+
   final CreateBuilderFunc? createEmptyInstance;
 
   BuilderInfo(
     String? messageName, {
     PackageName package = const PackageName(''),
     this.createEmptyInstance,
-    this.toProto3Json,
-    this.fromProto3Json,
-  }) : qualifiedMessageName = '${package.prefix}$messageName';
+    WellKnownType? wellKnownType,
+  }) : qualifiedMessageName = '${package.prefix}$messageName',
+       _wellKnownType = wellKnownType;
 
   void add<T>(
     int tagNumber,

protobuf/lib/src/protobuf/internal.dart

@@ -18,6 +18,7 @@ import 'package:meta/meta.dart' show UseResult;
 import 'consts.dart';
 import 'json/json.dart' as json_lib;
 import 'json_parsing_context.dart';
+import 'mixins/well_known.dart';
 import 'permissive_compare.dart';
 import 'type_registry.dart';
 import 'utils.dart';

protobuf/lib/src/protobuf/mixins/well_known.dart

@@ -6,9 +6,30 @@ import 'dart:convert';
 
 import 'package:fixnum/fixnum.dart';
 
-import '../../../protobuf.dart';
+import '../internal.dart';
 import '../json_parsing_context.dart';
 
+/// The set of well known protobuf message types which may have customized
+/// serialization logic.
+enum WellKnownType {
+  any,
+  timestamp,
+  duration,
+  struct,
+  value,
+  listValue,
+  fieldMask,
+  doubleValue,
+  floatValue,
+  int64Value,
+  uint64Value,
+  int32Value,
+  uint32Value,
+  boolValue,
+  stringValue,
+  bytesValue,
+}
+
 mixin AnyMixin implements GeneratedMessage {
   String get typeUrl;
   set typeUrl(String value);
@@ -98,14 +119,7 @@ mixin AnyMixin implements GeneratedMessage {
       );
     }
     final unpacked = info.createEmptyInstance!()..mergeFromBuffer(any.value);
-    final proto3Json = unpacked.toProto3Json(typeRegistry: typeRegistry);
-    if (info.toProto3Json == null) {
-      final map = proto3Json as Map<String, dynamic>;
-      map['@type'] = any.typeUrl;
-      return map;
-    } else {
-      return {'@type': any.typeUrl, 'value': proto3Json};
-    }
+    return writeToProto3JsonAny(unpacked.fieldSet, any.typeUrl, typeRegistry);
   }
 
   static void fromProto3JsonHelper(
@@ -133,21 +147,13 @@ mixin AnyMixin implements GeneratedMessage {
         );
       }
 
-      final Object? subJson =
-          info.fromProto3Json == null
-              // TODO(sigurdm): avoid cloning [object] here.
-              ? (Map<String, dynamic>.from(object)..remove('@type'))
-              : object['value'];
-      // TODO(sigurdm): We lose [context.path].
-      final packedMessage =
-          info.createEmptyInstance!()..mergeFromProto3Json(
-            subJson,
-            typeRegistry: typeRegistry,
-            supportNamesWithUnderscores: context.supportNamesWithUnderscores,
-            ignoreUnknownFields: context.ignoreUnknownFields,
-            permissiveEnums: context.permissiveEnums,
-          );
-
+      final packedMessage = info.createEmptyInstance!();
+      mergeFromProto3JsonAny(
+        json,
+        packedMessage.fieldSet,
+        typeRegistry,
+        context,
+      );
       any.value = packedMessage.writeToBuffer();
       any.typeUrl = typeUrl;
     } else {