Improved enum decoding 4

protobuf/lib/src/protobuf/builder_info.dart

@@ -62,7 +62,9 @@ class BuilderInfo {
       dynamic defaultOrMaker,
       CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
+      bool? sparseEnum,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
       {String? protoName}) {
     final index = byIndex.length;
     final fieldInfo = (tagNumber == 0)
@@ -71,7 +73,9 @@ class BuilderInfo {
             defaultOrMaker: defaultOrMaker,
             subBuilder: subBuilder,
             valueOf: valueOf,
+            sparseEnum: sparseEnum,
             enumValues: enumValues,
+            enumValuesByTag: enumValuesByTag,
             protoName: protoName);
     _addField(fieldInfo);
   }
@@ -99,13 +103,17 @@ class BuilderInfo {
       CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
+      bool? sparseEnum,
       {ProtobufEnum? defaultEnumValue,
       String? protoName}) {
     final index = byIndex.length;
     _addField(FieldInfo<T>.repeated(
         name, tagNumber, index, fieldType, check, subBuilder,
         valueOf: valueOf,
         enumValues: enumValues,
+        enumValuesByTag: enumValuesByTag,
+        sparseEnum: sparseEnum,
         defaultEnumValue: defaultEnumValue,
         protoName: protoName));
   }
@@ -127,74 +135,84 @@ class BuilderInfo {
       {dynamic defaultOrMaker,
       CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
+      bool? sparseEnum,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum>? enumValuesByTag,
       String? protoName}) {
     add<T>(tagNumber, name, fieldType, defaultOrMaker, subBuilder, valueOf,
-        enumValues,
+        sparseEnum, enumValues, enumValuesByTag,
         protoName: protoName);
   }
 
   /// Adds PbFieldType.OS String with no default value to reduce generated
   /// code size.
   void aOS(int tagNumber, String name, {String? protoName}) {
-    add<String>(tagNumber, name, PbFieldType.OS, null, null, null, null,
+    add<String>(
+        tagNumber, name, PbFieldType.OS, null, null, null, null, null, null,
         protoName: protoName);
   }
 
   /// Adds PbFieldType.PS String with no default value.
   void pPS(int tagNumber, String name, {String? protoName}) {
     addRepeated<String>(tagNumber, name, PbFieldType.PS,
-        getCheckFunction(PbFieldType.PS), null, null, null,
+        getCheckFunction(PbFieldType.PS), null, null, null, null, null,
         protoName: protoName);
   }
 
   /// Adds PbFieldType.QS String with no default value.
   void aQS(int tagNumber, String name, {String? protoName}) {
-    add<String>(tagNumber, name, PbFieldType.QS, null, null, null, null,
+    add<String>(
+        tagNumber, name, PbFieldType.QS, null, null, null, null, null, null,
         protoName: protoName);
   }
 
   /// Adds Int64 field with Int64.ZERO default.
   void aInt64(int tagNumber, String name, {String? protoName}) {
     add<Int64>(tagNumber, name, PbFieldType.O6, Int64.ZERO, null, null, null,
+        null, null,
         protoName: protoName);
   }
 
   /// Adds a boolean with no default value.
   void aOB(int tagNumber, String name, {String? protoName}) {
-    add<bool>(tagNumber, name, PbFieldType.OB, null, null, null, null,
+    add<bool>(
+        tagNumber, name, PbFieldType.OB, null, null, null, null, null, null,
         protoName: protoName);
   }
 
   // Enum.
   void e<T>(int tagNumber, String name, int fieldType,
       {dynamic defaultOrMaker,
       ValueOfFunc? valueOf,
+      bool? sparseEnum,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
       String? protoName}) {
-    add<T>(
-        tagNumber, name, fieldType, defaultOrMaker, null, valueOf, enumValues,
+    add<T>(tagNumber, name, fieldType, defaultOrMaker, null, valueOf,
+        sparseEnum, enumValues, enumValuesByTag,
         protoName: protoName);
   }
 
   // Repeated, not a message, group, or enum.
   void p<T>(int tagNumber, String name, int fieldType, {String? protoName}) {
     assert(!_isGroupOrMessage(fieldType) && !_isEnum(fieldType));
     addRepeated<T>(tagNumber, name, fieldType, getCheckFunction(fieldType),
-        null, null, null,
+        null, null, null, null, null,
         protoName: protoName);
   }
 
   // Repeated message, group, or enum.
   void pc<T>(int tagNumber, String name, int fieldType,
       {CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
+      bool? sparseEnum,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
       ProtobufEnum? defaultEnumValue,
       String? protoName}) {
     assert(_isGroupOrMessage(fieldType) || _isEnum(fieldType));
     addRepeated<T>(tagNumber, name, fieldType, _checkNotNull, subBuilder,
-        valueOf, enumValues,
+        valueOf, enumValues, enumValuesByTag, sparseEnum,
         defaultEnumValue: defaultEnumValue, protoName: protoName);
   }
 
@@ -208,6 +226,8 @@ class BuilderInfo {
         subBuilder,
         null,
         null,
+        null,
+        null,
         protoName: protoName);
   }
 
@@ -221,6 +241,8 @@ class BuilderInfo {
         subBuilder,
         null,
         null,
+        null,
+        null,
         protoName: protoName);
   }
 
@@ -238,16 +260,27 @@ class BuilderInfo {
       required int valueFieldType,
       CreateBuilderFunc? valueCreator,
       ValueOfFunc? valueOf,
+      bool? sparseEnum,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
       ProtobufEnum? defaultEnumValue,
       PackageName packageName = const PackageName(''),
       String? protoName,
       dynamic valueDefaultOrMaker}) {
-    final mapEntryBuilderInfo = BuilderInfo(entryClassName,
-        package: packageName)
-      ..add(PbMap._keyFieldNumber, 'key', keyFieldType, null, null, null, null)
-      ..add(PbMap._valueFieldNumber, 'value', valueFieldType,
-          valueDefaultOrMaker, valueCreator, valueOf, enumValues);
+    final mapEntryBuilderInfo =
+        BuilderInfo(entryClassName, package: packageName)
+          ..add(PbMap._keyFieldNumber, 'key', keyFieldType, null, null, null,
+              null, null, null)
+          ..add(
+              PbMap._valueFieldNumber,
+              'value',
+              valueFieldType,
+              valueDefaultOrMaker,
+              valueCreator,
+              valueOf,
+              sparseEnum,
+              enumValues,
+              enumValuesByTag);
 
     addMapField<K, V>(tagNumber, name, keyFieldType, valueFieldType,
         mapEntryBuilderInfo, valueCreator,
@@ -323,13 +356,31 @@ class BuilderInfo {
 
   ProtobufEnum? _decodeEnum(
       int tagNumber, ExtensionRegistry? registry, int rawValue) {
-    final f = valueOfFunc(tagNumber);
-    if (f != null) {
-      return f(rawValue);
+    final fi = fieldInfo[tagNumber];
+    if (fi == null) {
+      return _decodeEnumExtension(tagNumber, registry, rawValue);
+    }
+
+    final valuesByTag = fi.enumValuesByTag;
+    if (valuesByTag == null) {
+      return _decodeEnumExtension(tagNumber, registry, rawValue);
+    }
+
+    if (fi.sparseEnum) {
+      return ProtobufEnum.$_binarySearch(valuesByTag, rawValue);
+    } else {
+      if (rawValue >= 0 && rawValue < valuesByTag.length) {
+        return valuesByTag[rawValue];
+      } else {
+        return null;
+      }
     }
-    return registry
-        ?.getExtension(qualifiedMessageName, tagNumber)
-        ?.valueOf
-        ?.call(rawValue);
   }
+
+  ProtobufEnum? _decodeEnumExtension(
+          int tagNumber, ExtensionRegistry? registry, int rawValue) =>
+      registry
+          ?.getExtension(qualifiedMessageName, tagNumber)
+          ?.valueOf
+          ?.call(rawValue);
 }

protobuf/lib/src/protobuf/extension.dart

@@ -13,22 +13,32 @@ class Extension<T> extends FieldInfo<T> {
       CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
+      bool? sparseEnum,
       String? protoName})
       : super(name, tagNumber, null, fieldType,
             defaultOrMaker: defaultOrMaker,
             subBuilder: subBuilder,
             valueOf: valueOf,
             enumValues: enumValues,
+            enumValuesByTag: enumValuesByTag,
+            sparseEnum: sparseEnum,
             protoName: protoName);
 
   Extension.repeated(this.extendee, String name, int tagNumber, int fieldType,
       {required CheckFunc<T> check,
       CreateBuilderFunc? subBuilder,
       ValueOfFunc? valueOf,
       List<ProtobufEnum>? enumValues,
+      List<ProtobufEnum?>? enumValuesByTag,
+      bool? sparseEnum,
       String? protoName})
       : super.repeated(name, tagNumber, null, fieldType, check, subBuilder,
-            valueOf: valueOf, enumValues: enumValues, protoName: protoName);
+            valueOf: valueOf,
+            enumValues: enumValues,
+            enumValuesByTag: enumValuesByTag,
+            sparseEnum: sparseEnum,
+            protoName: protoName);
 
   @override
   int get hashCode => extendee.hashCode * 31 + tagNumber;

protobuf/lib/src/protobuf/field_info.dart

@@ -78,11 +78,14 @@ class FieldInfo<T> {
   /// Only available in fields with message type.
   final CreateBuilderFunc? subBuilder;
 
-  /// List of all enum values.
+  /// List of all enum values, in the order they appear in the proto definition.
+  /// (not sorted by enum name or value)
   ///
   /// Only available in enum fields.
   final List<ProtobufEnum>? enumValues;
 
+  final List<ProtobufEnum?>? enumValuesByTag;
+
   /// Default enum value.
   ///
   /// Only available in enum fields.
@@ -93,6 +96,14 @@ class FieldInfo<T> {
   /// Only available in enum fields.
   final ValueOfFunc? valueOf;
 
+  /// Tells the binary decoder how to search in the enum list by tag.
+  ///
+  /// When the enum is "sparse", the decoder binarys earches.
+  ///
+  /// Otherwise the decoder indexes the list (after a range check) with the enum
+  /// value on the wire.
+  final bool sparseEnum;
+
   /// Function to verify items when adding to a repeated field.
   ///
   /// Only available in repeated fields.
@@ -103,9 +114,12 @@ class FieldInfo<T> {
       this.subBuilder,
       this.valueOf,
       this.enumValues,
+      this.enumValuesByTag,
+      bool? sparseEnum,
       this.defaultEnumValue,
       String? protoName})
       : makeDefault = findMakeDefault(type, defaultOrMaker),
+        sparseEnum = sparseEnum ?? false,
         check = null,
         _protoName = protoName,
         assert(type != 0),
@@ -122,16 +136,24 @@ class FieldInfo<T> {
         type = 0,
         makeDefault = null,
         valueOf = null,
+        sparseEnum = false,
         check = null,
         enumValues = null,
+        enumValuesByTag = null,
         defaultEnumValue = null,
         subBuilder = null;
 
   FieldInfo.repeated(this.name, this.tagNumber, this.index, this.type,
       CheckFunc<T> this.check, this.subBuilder,
-      {this.valueOf, this.enumValues, this.defaultEnumValue, String? protoName})
+      {this.valueOf,
+      bool? sparseEnum,
+      this.enumValues,
+      this.enumValuesByTag,
+      this.defaultEnumValue,
+      String? protoName})
       : makeDefault = (() => PbList<T>(check: check)),
         _protoName = protoName,
+        sparseEnum = sparseEnum ?? false,
         assert(_isRepeated(type)),
         assert(!_isEnum(type) || valueOf != null);
 
@@ -277,7 +299,7 @@ class MapFieldInfo<K, V> extends FieldInfo<PbMap<K, V>?> {
             defaultOrMaker: () => PbMap<K, V>(keyFieldType, valueFieldType),
             defaultEnumValue: defaultEnumValue,
             protoName: protoName) {
-    assert(!_isEnum(type) || valueOf != null);
+    assert(!_isEnum(type) || (valueOf != null && sparseEnum != null));
   }
 
   FieldInfo get valueFieldInfo =>