Support for Any (flutter#112)

* Support for Any

Author: sigurdm

.gitignore

@@ -2,6 +2,7 @@
 .idea/
 .packages
 .pub
+.idea
 out
 packages
 pubspec.lock

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.10.0
+
+* Breaking change: Support for [any](https://developers.google.com/protocol-buffers/docs/proto3#any) messages.
+  Generated files require package:protobuf version 0.10.1 or newer.
+  `BuilderInfo.messageName` will now be the fully qualified name for generated messages.
+
 ## 0.9.0
 
 * Breaking change: Add `copyWith()` to message classes and update `getDefault()` to use `freeze()`.

Makefile

@@ -12,6 +12,7 @@ PLUGIN_PATH=bin/$(PLUGIN_NAME)
 BENCHMARK_PROTOS = $(wildcard benchmark/protos/*.proto)
 
 TEST_PROTO_LIST = \
+	google/protobuf/any \
 	google/protobuf/unittest_import \
 	google/protobuf/unittest_optimize_for \
 	google/protobuf/unittest \
@@ -36,7 +37,8 @@ TEST_PROTO_LIST = \
 	service2 \
 	service3 \
 	toplevel_import \
-	toplevel
+	toplevel \
+	using_any
 TEST_PROTO_DIR=$(OUTPUT_DIR)/protos
 TEST_PROTO_LIBS=$(foreach f, $(TEST_PROTO_LIST), \
   $(TEST_PROTO_DIR)/$(f).pb.dart \

lib/code_generator.dart

@@ -7,7 +7,13 @@ part of protoc;
 abstract class ProtobufContainer {
   String get package;
   String get classname;
-  String get fqname;
+  String get fullName;
+
+  /// The fully qualified name with a leading '.'.
+  ///
+  /// This exists because names from protoc come like this.
+  String get dottedName => '.$fullName';
+
   String get packageImportPrefix =>
       _cachedImportPrefix ??= _calculateImportPrefix();
 
@@ -83,6 +89,6 @@ class CodeGenerator extends ProtobufContainer {
 
   String get package => '';
   String get classname => null;
-  String get fqname => '';
+  String get fullName => '';
   get fileGen => null;
 }

lib/enum_generator.dart

@@ -13,22 +13,21 @@ class EnumAlias {
 class EnumGenerator extends ProtobufContainer {
   final ProtobufContainer _parent;
   final String classname;
-  final String fqname;
+  final String fullName;
   final EnumDescriptorProto _descriptor;
   final List<EnumValueDescriptorProto> _canonicalValues =
       <EnumValueDescriptorProto>[];
   final List<EnumAlias> _aliases = <EnumAlias>[];
 
   EnumGenerator(EnumDescriptorProto descriptor, ProtobufContainer parent)
-      : _parent = parent,
-        classname = (parent == null || parent is FileGenerator)
+      : assert(parent != null),
+        _parent = parent,
+        classname = (parent is FileGenerator)
             ? descriptor.name
             : '${parent.classname}_${descriptor.name}',
-        fqname = (parent == null || parent.fqname == null)
+        fullName = parent.fullName == ''
             ? descriptor.name
-            : (parent.fqname == '.'
-                ? '.${descriptor.name}'
-                : '${parent.fqname}.${descriptor.name}'),
+            : '${parent.fullName}.${descriptor.name}',
         _descriptor = descriptor {
     for (EnumValueDescriptorProto value in descriptor.value) {
       EnumValueDescriptorProto canonicalValue =
@@ -46,7 +45,7 @@ class EnumGenerator extends ProtobufContainer {
 
   /// Make this enum available as a field type.
   void register(GenerationContext ctx) {
-    ctx.registerFieldType(fqname, this);
+    ctx.registerFieldType(this);
   }
 
   /// Returns a const expression that evaluates to the JSON for this message.

lib/extension_generator.dart

@@ -11,7 +11,7 @@ class ExtensionGenerator {
   // populated by resolve()
   ProtobufField _field;
   String _extensionName;
-  String _extendedClassName = "";
+  String _extendedFullName = "";
 
   ExtensionGenerator(this._descriptor, this._parent);
 
@@ -22,7 +22,7 @@ class ExtensionGenerator {
     ProtobufContainer extendedType = ctx.getFieldType(_descriptor.extendee);
     // TODO(skybrian) When would this be null?
     if (extendedType != null) {
-      _extendedClassName = extendedType.classname;
+      _extendedFullName = extendedType.fullName;
     }
   }
 
@@ -80,7 +80,7 @@ class ExtensionGenerator {
 
     if (_field.isRepeated) {
       out.print('static final $_protobufImportPrefix.Extension $name = '
-          'new $_protobufImportPrefix.Extension<$dartType>.repeated(\'$_extendedClassName\','
+          'new $_protobufImportPrefix.Extension<$dartType>.repeated(\'$_extendedFullName\','
           ' \'$name\', ${_field.number}, ${_field.typeConstant}');
       if (type.isMessage || type.isGroup) {
         out.println(', $dartType.$checkItem, $dartType.create);');
@@ -95,7 +95,7 @@ class ExtensionGenerator {
     }
 
     out.print('static final $_protobufImportPrefix.Extension $name = '
-        'new $_protobufImportPrefix.Extension<$dartType>(\'$_extendedClassName\', \'$name\', '
+        'new $_protobufImportPrefix.Extension<$dartType>(\'$_extendedFullName\', \'$name\', '
         '${_field.number}, ${_field.typeConstant}');
 
     String initializer = _field.generateDefaultFunction(package);

lib/file_generator.dart

@@ -163,7 +163,7 @@ class FileGenerator extends ProtobufContainer {
 
   String get package => descriptor.package;
   String get classname => '';
-  String get fqname => '.${descriptor.package}';
+  String get fullName => descriptor.package;
   FileGenerator get fileGen => this;
 
   /// Generates all the Dart files for this .proto file.

lib/grpc_generator.dart

@@ -73,7 +73,7 @@ class GrpcServiceGenerator {
       return;
     }
     mg.checkResolved();
-    _deps[mg.fqname] = mg;
+    _deps[mg.dottedName] = mg;
   }
 
   /// Adds dependencies of [generate] to [imports].

lib/linker.dart

@@ -55,8 +55,10 @@ class GenerationContext {
   }
 
   /// Makes a message, group, or enum available for reference.
-  void registerFieldType(String name, ProtobufContainer type) {
-    _typeRegistry[name] = type;
+  void registerFieldType(ProtobufContainer type) {
+    // Register the name with a leading '.' to be compatible with input from
+    // protoc.
+    _typeRegistry[type.dottedName] = type;
   }
 
   /// Returns info about a .pb.dart being imported,

lib/message_generator.dart

@@ -27,10 +27,27 @@ class MessageGenerator extends ProtobufContainer {
   /// The name of the Dart class to generate.
   final String classname;
 
-  /// The fully-qualified name of the message type.
+  /// The fully-qualified name of the message (without any leading '.').
+  final String fullName;
+
+  /// The part of the fully qualified name that comes after the package prefix.
+  ///
+  /// For nested messages this will include the names of the parents.
   ///
-  /// (Used as a unique key and in error messages, not in Dart code.)
-  final String fqname;
+  /// For example:
+  /// ```
+  /// package foo;
+  ///
+  /// message Container {
+  ///   message Nested {
+  ///     int32 int32_value = 1;
+  ///   }
+  /// }
+  /// ```
+  /// The nested message will have a `fullName` of 'foo.Container.Nested', and a
+  /// `messageName` of 'Container.Nested'.
+  String get messageName =>
+      fullName.substring(package.length == 0 ? 0 : package.length + 1);
 
   final PbMixin mixin;
 
@@ -48,11 +65,10 @@ class MessageGenerator extends ProtobufContainer {
       : _descriptor = descriptor,
         _parent = parent,
         classname = messageClassName(descriptor, parent: parent.classname),
-        fqname = (parent == null || parent.fqname == null)
+        assert(parent != null),
+        fullName = parent.fullName == ''
             ? descriptor.name
-            : (parent.fqname == '.'
-                ? '.${descriptor.name}'
-                : '${parent.fqname}.${descriptor.name}'),
+            : '${parent.fullName}.${descriptor.name}',
         mixin = _getMixin(descriptor, parent.fileGen.descriptor, declaredMixins,
             defaultMixin) {
     for (EnumDescriptorProto e in _descriptor.enumType) {
@@ -77,7 +93,7 @@ class MessageGenerator extends ProtobufContainer {
   /// Throws an exception if [resolve] hasn't been called yet.
   void checkResolved() {
     if (_fieldList == null) {
-      throw new StateError("message not resolved: ${fqname}");
+      throw new StateError("message not resolved: ${fullName}");
     }
   }
 
@@ -103,7 +119,7 @@ class MessageGenerator extends ProtobufContainer {
 
   // Registers message and enum types that can be used elsewhere.
   void register(GenerationContext ctx) {
-    ctx.registerFieldType(fqname, this);
+    ctx.registerFieldType(this);
     for (var m in _messageGenerators) {
       m.register(ctx);
     }
@@ -205,11 +221,15 @@ class MessageGenerator extends ProtobufContainer {
       mixinClause = ' with ${mixinNames.join(", ")}';
     }
 
+    String packageClause = package == ''
+        ? ''
+        : ', package: const $_protobufImportPrefix.PackageName(\'$package\')';
     out.addBlock(
         'class ${classname} extends $_protobufImportPrefix.GeneratedMessage${mixinClause} {',
         '}', () {
       out.addBlock(
-          'static final $_protobufImportPrefix.BuilderInfo _i = new $_protobufImportPrefix.BuilderInfo(\'${classname}\')',
+          'static final $_protobufImportPrefix.BuilderInfo _i = '
+          'new $_protobufImportPrefix.BuilderInfo(\'${messageName}\'$packageClause)',
           ';', () {
         for (ProtobufField field in _fieldList) {
           var dartFieldName = field.memberNames.fieldName;
@@ -255,9 +275,12 @@ class MessageGenerator extends ProtobufContainer {
       out.println('static ${classname} _defaultInstance;');
       out.addBlock('static void $checkItem($classname v) {', '}', () {
         out.println('if (v is! $classname)'
-            " $_protobufImportPrefix.checkItemFailed(v, '$classname');");
+            " $_protobufImportPrefix.checkItemFailed(v, _i.messageName);");
       });
       generateFieldsAccessorsMutators(out);
+      if (fullName == 'google.protobuf.Any') {
+        generateAnyMethods(out);
+      }
     });
     out.println();
   }
@@ -271,7 +294,7 @@ class MessageGenerator extends ProtobufContainer {
   bool _hasRequiredFields(MessageGenerator type, Set alreadySeen) {
     if (type._fieldList == null) throw new StateError("message not resolved");
 
-    if (alreadySeen.contains(type.fqname)) {
+    if (alreadySeen.contains(type.fullName)) {
       // The type is already in cache.  This means that either:
       // a. The type has no required fields.
       // b. We are in the midst of checking if the type has required fields,
@@ -282,7 +305,7 @@ class MessageGenerator extends ProtobufContainer {
       //    here.
       return false;
     }
-    alreadySeen.add(type.fqname);
+    alreadySeen.add(type.fullName);
     // If the type has extensions, an extension with message type could contain
     // required fields, so we have to be conservative and assume such an
     // extension exists.
@@ -304,6 +327,45 @@ class MessageGenerator extends ProtobufContainer {
     return false;
   }
 
+  /// Generates methods for the Any message class for packing and unpacking
+  /// values.
+  void generateAnyMethods(IndentingWriter out) {
+    out.println('''
+  /// Unpacks the message in [value] into [instance].
+  ///
+  /// Throws a [InvalidProtocolBufferException] if [typeUrl] does not correspond
+  /// to the type of [instance].
+  ///
+  /// A typical usage would be `any.unpackInto(new Message())`.
+  ///
+  /// Returns [instance].
+  T unpackInto<T extends $_protobufImportPrefix.GeneratedMessage>(T instance,
+      {$_protobufImportPrefix.ExtensionRegistry extensionRegistry = $_protobufImportPrefix.ExtensionRegistry.EMPTY}) {
+    $_protobufImportPrefix.unpackIntoHelper(value, instance, typeUrl,
+        extensionRegistry: extensionRegistry);
+    return instance;
+  }
+
+  /// Returns `true` if the encoded message matches the type of [instance].
+  ///
+  /// Can be used with a default instance:
+  /// `any.canUnpackInto(Message.getDefault())`
+  bool canUnpackInto($_protobufImportPrefix.GeneratedMessage instance) {
+    return $_protobufImportPrefix.canUnpackIntoHelper(instance, typeUrl);
+  }
+
+  /// Creates a new [Any] encoding [message].
+  ///
+  /// The [typeUrl] will be [typeUrlPrefix]/`fullName` where `fullName` is
+  /// the fully qualified name of the type of [message].
+  static Any pack($_protobufImportPrefix.GeneratedMessage message,
+      {String typeUrlPrefix = 'type.googleapis.com'}) {
+    return new Any()
+      ..value = message.writeToBuffer()
+      ..typeUrl = '\${typeUrlPrefix}/\${message.info_.messageName}';
+  }''');
+  }
+
   void generateFieldsAccessorsMutators(IndentingWriter out) {
     for (ProtobufField field in _fieldList) {
       out.println();
@@ -324,15 +386,15 @@ class MessageGenerator extends ProtobufContainer {
 
     if (field.isRepeated) {
       if (field.overridesSetter) {
-        throw 'Field ${field.fqname} cannot override a setter for '
+        throw 'Field ${field.fullName} cannot override a setter for '
             '${names.fieldName} because it is repeated.';
       }
       if (field.overridesHasMethod) {
-        throw 'Field ${field.fqname} cannot override '
+        throw 'Field ${field.fullName} cannot override '
             '${names.hasMethodName}() because it is repeated.';
       }
       if (field.overridesClearMethod) {
-        throw 'Field ${field.fqname} cannot override '
+        throw 'Field ${field.fullName} cannot override '
             '${names.clearMethodName}() because it is repeated.';
       }
     } else {