Add support for map fields. (flutter#140)

Author: szakarias

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 0.10.5
+
+* Added support for [map fields](https://developers.google.com/protocol-buffers/docs/proto3#maps).
+  Map fields are now represented as Dart maps and are accessed through a getter with the same name as the map field.
+  To use the map support, use Dart protoc_plugin version 11.0 or newer.
+
+
 ## 0.10.4
 
 * Added separate getter for `BuilderInfo.qualifiedMessageName`.

lib/meta.dart

@@ -48,12 +48,14 @@ const GeneratedMessage_reservedNames = const <String>[
   'GeneratedMessage',
   'Object',
   'eventPlugin',
+  'createMapField',
   'createRepeatedField',
   'unknownFields',
   'clone',
   r'$_get',
   r'$_getI64',
   r'$_getList',
+  r'$_getMap',
   r'$_getN',
   r'$_getS',
   r'$_has',

lib/protobuf.dart

@@ -5,7 +5,7 @@
 library protobuf;
 
 import 'dart:async' show Future;
-import 'dart:collection' show ListBase;
+import 'dart:collection' show ListBase, MapBase;
 import 'dart:convert'
     show base64Decode, base64Encode, jsonEncode, jsonDecode, Utf8Codec;
 import 'dart:math' as math;
@@ -30,6 +30,7 @@ part 'src/protobuf/generated_message.dart';
 part 'src/protobuf/generated_service.dart';
 part 'src/protobuf/json.dart';
 part 'src/protobuf/pb_list.dart';
+part 'src/protobuf/pb_map.dart';
 part 'src/protobuf/protobuf_enum.dart';
 part 'src/protobuf/readonly_message.dart';
 part 'src/protobuf/rpc_client.dart';

lib/src/protobuf/builder_info.dart

@@ -32,6 +32,19 @@ class BuilderInfo {
         defaultOrMaker, subBuilder, valueOf, enumValues));
   }
 
+  void addMapField<K, V>(
+      int tagNumber,
+      String name,
+      int keyFieldType,
+      int valueFieldType,
+      CreateBuilderFunc valueCreator,
+      ValueOfFunc valueOf,
+      List<ProtobufEnum> enumValues) {
+    var index = byIndex.length;
+    _addField(MapFieldInfo<K, V>.map(name, tagNumber, index, PbFieldType.M,
+        keyFieldType, valueFieldType, valueCreator, valueOf, enumValues));
+  }
+
   void addRepeated<T>(
       int tagNumber,
       String name,
@@ -113,6 +126,15 @@ class BuilderInfo {
         tagNumber, name, fieldType, check, subBuilder, valueOf, enumValues);
   }
 
+  // Map field.
+  void m<K, V>(int tagNumber, String name, int keyFieldType, int valueFieldType,
+      [CreateBuilderFunc valueCreator,
+      ValueOfFunc valueOf,
+      List<ProtobufEnum> enumValues]) {
+    addMapField<K, V>(tagNumber, name, keyFieldType, valueFieldType,
+        valueCreator, valueOf, enumValues);
+  }
+
   bool containsTagNumber(int tagNumber) => fieldInfo.containsKey(tagNumber);
 
   defaultValue(int tagNumber) {

lib/src/protobuf/coded_buffer.dart

@@ -217,6 +217,9 @@ void _mergeFromCodedBufferReader(
         input.readMessage(subMessage, registry);
         fs._ensureRepeatedField(fi).add(subMessage);
         break;
+      case PbFieldType._MAP:
+        fs._ensureMapField(fi).add(input, registry);
+        break;
       default:
         throw 'Unknown field type $fieldType';
     }

lib/src/protobuf/coded_buffer_writer.dart

@@ -79,13 +79,30 @@ class CodedBufferWriter {
 
     final int wireFormat = _wireTypes[_valueTypeIndex(valueType)];
 
+    if ((fieldType & PbFieldType._MAP_BIT) != 0) {
+      final int keyWireFormat =
+          _wireTypes[_valueTypeIndex(fieldValue.keyFieldType)];
+      final int valueWireFormat =
+          _wireTypes[_valueTypeIndex(fieldValue.valueFieldType)];
+
+      fieldValue.forEach((key, value) {
+        _writeTag(fieldNumber, WIRETYPE_LENGTH_DELIMITED);
+        final mark = _startLengthDelimited();
+        _writeValue(
+            PbMap._keyFieldNumber, fieldValue.keyFieldType, key, keyWireFormat);
+        _writeValue(PbMap._valueFieldNumber, fieldValue.valueFieldType, value,
+            valueWireFormat);
+        _endLengthDelimited(mark);
+      });
+      return;
+    }
+
     if ((fieldType & PbFieldType._REPEATED_BIT) != 0) {
       for (var i = 0; i < fieldValue.length; i++) {
         _writeValue(fieldNumber, valueType, fieldValue[i], wireFormat);
       }
       return;
     }
-
     _writeValue(fieldNumber, valueType, fieldValue, wireFormat);
   }
 

lib/src/protobuf/field_info.dart

@@ -55,6 +55,16 @@ class FieldInfo<T> {
     assert(!_isEnum(type) || valueOf != null);
   }
 
+  FieldInfo._map(
+      this.name, this.tagNumber, this.index, int type, this.makeDefault,
+      [dynamic defaultOrMaker, this.subBuilder, this.valueOf, this.enumValues])
+      : this.type = type,
+        this.check = null {
+    assert(name != null);
+    assert(tagNumber != null);
+    assert(_isMapField(type));
+  }
+
   static MakeDefaultFunc findMakeDefault(int type, dynamic defaultOrMaker) {
     if (defaultOrMaker == null) return PbFieldType._defaultForType(type);
     if (defaultOrMaker is MakeDefaultFunc) return defaultOrMaker;
@@ -65,6 +75,7 @@ class FieldInfo<T> {
   bool get isRepeated => _isRepeated(type);
   bool get isGroupOrMessage => _isGroupOrMessage(type);
   bool get isEnum => _isEnum(type);
+  bool get isMapField => _isMapField(type);
 
   /// Returns a read-only default value for a field.
   /// (Unlike getField, doesn't create a repeated field.)
@@ -147,3 +158,38 @@ class FieldInfo<T> {
 
   String toString() => name;
 }
+
+class MapFieldInfo<K, V> extends FieldInfo<PbMap<K, V>> {
+  int keyFieldType;
+  int valueFieldType;
+  CreateBuilderFunc valueCreator;
+
+  MapFieldInfo.map(String name, int tagNumber, int index, int type,
+      this.keyFieldType, this.valueFieldType,
+      [this.valueCreator, ValueOfFunc valueOf, List<ProtobufEnum> enumValues])
+      : super._map(
+            name,
+            tagNumber,
+            index,
+            type,
+            () => PbMap<K, V>(keyFieldType, valueFieldType, valueCreator,
+                valueOf, enumValues),
+            null,
+            null,
+            valueOf,
+            enumValues) {
+    assert(name != null);
+    assert(tagNumber != null);
+    assert(_isMapField(type));
+    assert(!_isEnum(type) || valueOf != null);
+  }
+
+  Map<K, V> _ensureMapField(_FieldSet fs) {
+    return fs._ensureMapField<K, V>(this);
+  }
+
+  Map<K, V> _createMapField(GeneratedMessage m) {
+    assert(isMapField);
+    return m.createMapField<K, V>(tagNumber, this);
+  }
+}

lib/src/protobuf/field_set.dart

@@ -187,6 +187,17 @@ class _FieldSet {
     return value;
   }
 
+  Map<K, V> _getDefaultMap<K, V>(MapFieldInfo<K, V> fi) {
+    assert(fi.isMapField);
+    if (_isReadOnly)
+      return PbMap<K, V>.unmodifiable(PbMap<K, V>(fi.keyFieldType,
+          fi.valueFieldType, fi.valueCreator, fi.valueOf, fi.enumValues));
+
+    var value = fi._createMapField(_message);
+    _setNonExtensionFieldUnchecked(fi, value);
+    return value;
+  }
+
   _getFieldOrNullByTag(int tagNumber) {
     var fi = _getFieldInfoOrNull(tagNumber);
     if (fi == null) return null;
@@ -292,6 +303,19 @@ class _FieldSet {
     return newValue;
   }
 
+  PbMap<K, V> _ensureMapField<K, V>(MapFieldInfo<K, V> fi) {
+    assert(!_isReadOnly);
+    assert(fi.isMapField);
+    assert(fi.index != null); // Map fields are not allowed to be extensions.
+
+    var value = _getFieldOrNull(fi);
+    if (value != null) return value as Map<K, V>;
+
+    var newValue = fi._createMapField(_message);
+    _setNonExtensionFieldUnchecked(fi, newValue);
+    return newValue;
+  }
+
   /// Sets a non-extended field and fires events.
   void _setNonExtensionFieldUnchecked(FieldInfo fi, value) {
     if (_hasObservers) {
@@ -324,6 +348,13 @@ class _FieldSet {
     return _getDefaultList<T>(_nonExtensionInfoByIndex(index));
   }
 
+  /// The implementation of a generated getter for map fields.
+  Map<K, V> _$getMap<K, V>(int index) {
+    var value = _values[index];
+    if (value != null) return value as Map<K, V>;
+    return _getDefaultMap<K, V>(_nonExtensionInfoByIndex(index));
+  }
+
   /// The implementation of a generated getter for String fields.
   String _$getS(int index, String defaultValue) {
     var value = _values[index];
@@ -511,6 +542,8 @@ class _FieldSet {
         out.write('$indent$key: {\n');
         value._fieldSet.writeString(out, '$indent  ');
         out.write('$indent}\n');
+      } else if (value is MapEntry) {
+        out.write('$indent$key: {${value.key} : ${value.value}} \n');
       } else {
         out.write('$indent$key: $value\n');
       }
@@ -527,6 +560,10 @@ class _FieldSet {
         for (var value in fieldValue) {
           renderValue(fi.name, value);
         }
+      } else if (fieldValue is Map) {
+        for (var entry in fieldValue.entries) {
+          renderValue(fi.name, entry);
+        }
       } else {
         renderValue(fi.name, fieldValue);
       }
@@ -581,6 +618,20 @@ class _FieldSet {
 
     bool mustClone = _isGroupOrMessage(otherFi.type);
 
+    if (fi.isMapField) {
+      MapFieldInfo f = fi;
+      mustClone = _isGroupOrMessage(f.valueFieldType);
+      PbMap map = f._ensureMapField(this);
+      if (mustClone) {
+        for (MapEntry entry in fieldValue.entries) {
+          map[entry.key] = _cloneMessage(entry.value);
+        }
+      } else {
+        map.addAll(fieldValue);
+      }
+      return;
+    }
+
     if (fi.isRepeated) {
       if (mustClone) {
         // fieldValue must be a PbListBase of GeneratedMessage.

lib/src/protobuf/field_type.dart

@@ -14,12 +14,14 @@ bool _isEnum(int fieldType) =>
 bool _isGroupOrMessage(int fieldType) =>
     (fieldType & (PbFieldType._GROUP_BIT | PbFieldType._MESSAGE_BIT)) != 0;
 
+bool _isMapField(int fieldType) => (fieldType & PbFieldType._MAP_BIT) != 0;
+
 /// Defines constants and functions for dealing with fieldType bits.
 class PbFieldType {
   /// Returns the base field type without any of the required, repeated
   /// and packed bits.
   static int _baseType(int fieldType) =>
-      fieldType & ~(_REQUIRED_BIT | _REPEATED_BIT | _PACKED_BIT);
+      fieldType & ~(_REQUIRED_BIT | _REPEATED_BIT | _PACKED_BIT | _MAP_BIT);
 
   static MakeDefaultFunc _defaultForType(int type) {
     switch (type) {
@@ -92,6 +94,7 @@ class PbFieldType {
   static const int _SFIXED32_BIT = 0x80000;
   static const int _SFIXED64_BIT = 0x100000;
   static const int _MESSAGE_BIT = 0x200000;
+  static const int _MAP_BIT = 0x400000;
 
   static const int _OPTIONAL_BOOL = _BOOL_BIT;
   static const int _OPTIONAL_BYTES = _BYTES_BIT;
@@ -167,6 +170,7 @@ class PbFieldType {
   static const int _PACKED_SFIXED64 =
       _REPEATED_BIT | _PACKED_BIT | _SFIXED64_BIT;
 
+  static const int _MAP = _MAP_BIT | _MESSAGE_BIT;
   // Short names for use in generated code.
 
   // _O_ptional.
@@ -244,4 +248,6 @@ class PbFieldType {
   static const int KF6 = _PACKED_FIXED64;
   static const int KSF3 = _PACKED_SFIXED32;
   static const int KSF6 = _PACKED_SFIXED64;
+
+  static const int M = _MAP;
 }

lib/src/protobuf/generated_message.dart

@@ -252,6 +252,12 @@ abstract class GeneratedMessage {
     return new PbList<T>(check: fi.check);
   }
 
+  /// Creates a Map representing a map field.
+  Map<K, V> createMapField<K, V>(int tagNumber, MapFieldInfo<K, V> fi) {
+    return PbMap<K, V>(fi.keyFieldType, fi.valueFieldType, fi.valueCreator,
+        fi.valueOf, fi.enumValues);
+  }
+
   /// Returns the value of a field, ignoring any defaults.
   ///
   /// For unset or cleared fields, returns null.
@@ -321,6 +327,9 @@ abstract class GeneratedMessage {
   /// For generated code only.
   List<T> $_getList<T>(int index) => _fieldSet._$getList<T>(index);
 
+  /// For generated code only.
+  Map<K, V> $_getMap<K, V>(int index) => _fieldSet._$getMap<K, V>(index);
+
   /// For generated code only.
   String $_getS(int index, String defaultValue) =>
       _fieldSet._$getS(index, defaultValue);