New Mojom Parser: Serialization.

mojom/mojom_parser/serialization/serialization.go

Index: mojom/mojom_parser/serialization/serialization.go
diff --git a/mojom/mojom_parser/serialization/serialization.go b/mojom/mojom_parser/serialization/serialization.go
index ef1f8d34044ab605aa4e24daa8b3cbf17165ad3f..d2c44dfceff6b49bb7ac79da650647834fd8f97b 100644
--- a/mojom/mojom_parser/serialization/serialization.go
+++ b/mojom/mojom_parser/serialization/serialization.go
@@ -5,6 +5,10 @@
 package serialization
 
 import (
+	"fmt"
+	"mojo/public/go/bindings"
+	"mojom/mojom_parser/generated/mojom_files"
+	"mojom/mojom_parser/generated/mojom_types"
 	"mojom/mojom_parser/mojom"
 )
 
@@ -12,12 +16,544 @@ import (
 /// Mojom Descriptor Serialization
 //////////////////////////////////////////////////
 
+// This variable may be set to false in order to omit emitting line and
+// column numbers.
+var EmitLineAndColumnNumbers bool = true
+
 // Serializes the MojomDescriptor into a binary form that is passed to the
 // backend of the compiler in order to invoke the code generators.
 // To do this we use Mojo serialization.
 func Serialize(d *mojom.MojomDescriptor) (bytes []byte, err error) {
-	// TODO(rudominer) This is a stub. It will be implemented in a later
-	// CL.
-	bytes = []byte("DummyOutput")
+	fileGraph := translateDescriptor(d)
+	encoder := bindings.NewEncoder()
+	fileGraph.Encode(encoder)
+	bytes, _, err = encoder.Data()
+	return
+}
+
+// translateDescriptor translates from a mojom.MojomDescriptor (the pure Go
+// representation used by the parser) to a mojom_files.MojomFileGraph (the
+// Mojo Go representation used for serialization.)
+func translateDescriptor(d *mojom.MojomDescriptor) *mojom_files.MojomFileGraph {
+	fileGraph := mojom_files.MojomFileGraph{}
+
+	// Add |files| field.
+	fileGraph.Files = make(map[string]mojom_files.MojomFile)
+	for name, file := range d.MojomFilesByName {
+		fileGraph.Files[name] = translateMojomFile(file)
+	}
+
+	// Add |resolved_types| field.
+	fileGraph.ResolvedTypes = make(map[string]mojom_types.UserDefinedType)
+	for key, userDefinedType := range d.TypesByKey {
+		fileGraph.ResolvedTypes[key] = translateUserDefinedType(userDefinedType)
+	}
+
+	// Add |resolved_values| field.
+	fileGraph.ResolvedValues = make(map[string]mojom_types.UserDefinedValue)
+	for key, userDefinedValue := range d.ValuesByKey {
+		fileGraph.ResolvedValues[key] = translateUserDefinedValue(userDefinedValue)
+	}
+
+	return &fileGraph
+}
+
+// translateMojomFile translates from a mojom.MojomFile (the pure Go
+// representation used by the parser) to a mojom_files.MojomFile (the
+// Mojo Go representation used for serialization.)
+func translateMojomFile(f *mojom.MojomFile) (file mojom_files.MojomFile) {
+	// file_name field
+	file.FileName = f.CanonicalFileName
+
+	// module_namespace field
+	file.ModuleNamespace = newString(f.ModuleNamespace)
+
+	// attributes field
+	if f.Attributes != nil {
+		file.Attributes = new([]mojom_types.Attribute)
+		for _, attr := range f.Attributes.List {
+			*(file.Attributes) = append(*(file.Attributes), translateMojomAttribute(&attr))
+		}
+	}
+
+	// imports field
+	if len(f.Imports) > 0 {
+		file.Imports = new([]string)
+		for _, importName := range f.Imports {
+			*(file.Imports) = append(*(file.Imports), importName.CanonicalFileName)
+		}
+	}
+
+	// declared_mojom_objects field...
+
+	// Interfaces
+	if f.Interfaces != nil && len(f.Interfaces) > 0 {
+		file.DeclaredMojomObjects.Interfaces = new([]string)
+		for _, intrfc := range f.Interfaces {
+			*(file.DeclaredMojomObjects.Interfaces) = append(*(file.DeclaredMojomObjects.Interfaces), intrfc.TypeKey())

[mattr, 2015/11/10 19:26:49]

Why do we have a pointer to a slice?  Slices are already nilable and have a
separate zero.  Anyway I'm sure there's a reason.

[rudominer, 2015/11/10 23:29:36]

The Go code that defines a variable as a pointer to a slice is not hand-written
but is generated from Mojom. I didn't write the code that does the generation
but I think I can guess why it was done this way. It is because in Mojom there
is a distinction between an array of strings (array<string>) and a nullable
array of strings (array<string>?). The former gets translated to a string slice
and the latter to a pointer to a string slice.

+		}
+	}
+
+	// Structs
+	if f.Structs != nil && len(f.Structs) > 0 {
+		file.DeclaredMojomObjects.Structs = new([]string)
+		for _, strct := range f.Structs {
+			*(file.DeclaredMojomObjects.Structs) = append(*(file.DeclaredMojomObjects.Structs), strct.TypeKey())
+		}
+	}
+
+	// Unions
+	if f.Unions != nil && len(f.Unions) > 0 {
+		file.DeclaredMojomObjects.Unions = new([]string)
+		for _, union := range f.Unions {
+			*(file.DeclaredMojomObjects.Unions) = append(*(file.DeclaredMojomObjects.Unions), union.TypeKey())
+		}
+	}
+
+	// TopLevelEnums
+	if f.Enums != nil && len(f.Enums) > 0 {
+		file.DeclaredMojomObjects.TopLevelEnums = new([]string)
+		for _, enum := range f.Enums {
+			*(file.DeclaredMojomObjects.TopLevelEnums) = append(*(file.DeclaredMojomObjects.TopLevelEnums), enum.TypeKey())
+		}
+	}
+
+	// TopLevelConstants
+	if f.Constants != nil && len(f.Constants) > 0 {
+		file.DeclaredMojomObjects.TopLevelConstants = new([]string)
+		for _, constant := range f.Constants {
+			*(file.DeclaredMojomObjects.TopLevelConstants) = append(*(file.DeclaredMojomObjects.TopLevelConstants), constant.ValueKey())
+		}
+	}
+
+	// TODO(rudominer) Do we need the EmbeddedEnums and EmbeddedConstants
+	// fields in KeysByType. It seems these fields are not currently being
+	// used in mojom_translator.py.
+
+	return
+}
+
+// translateUserDefinedType translates from a mojom.UserDefinedType (the pure Go
+// representation used by the parser) to a mojom_types.UserDefinedType (the
+// Mojo Go representation used for serialization.)
+func translateUserDefinedType(t mojom.UserDefinedType) mojom_types.UserDefinedType {
+	switch p := t.(type) {
+	case *mojom.MojomStruct:
+		return &mojom_types.UserDefinedTypeStructType{translateMojomStruct(p)}
+	case *mojom.MojomInterface:
+		return translateMojomInterface(p)
+	case *mojom.MojomEnum:
+		return translateMojomEnum(p)
+	case *mojom.MojomUnion:
+		return translateMojomUnion(p)
+	default:
+		panic(fmt.Sprintf("Unexpected type: %T", t))
+
+	}
+}
+
+func translateMojomStruct(s *mojom.MojomStruct) mojom_types.MojomStruct {
+	mojomStruct := mojom_types.MojomStruct{}
+	mojomStruct.DeclData = translateDeclarationData(&s.DeclarationData)
+	mojomStruct.DeclData.ContainedDeclarations = translateContainedDeclarations(&s.DeclarationContainer)
+
+	for _, field := range s.Fields {
+		mojomStruct.Fields = append(mojomStruct.Fields, translateStructField(field))
+	}
+
+	// TODO(rudominer) Implement VersionInfo.
+	//mojomStruct.Value.VersionInfo = new([]mojom_types.StructVersion)
+
+	return mojomStruct
+}
+
+func translateStructField(f *mojom.StructField) (field mojom_types.StructField) {
+	field.DeclData = translateDeclarationData(&f.DeclarationData)
+	field.Type = translateTypeRef(f.FieldType)
+	if f.DefaultValue != nil {
+		field.DefaultValue = translateDefaultFieldValue(f.DefaultValue)
+	}
+	// TODO(rudominer) Implement field offsets.
+	field.Offset = f.Offset
 	return
 }
+
+func translateDefaultFieldValue(v mojom.ValueRef) mojom_types.DefaultFieldValue {
+	switch v := v.(type) {
+	case mojom.LiteralValue:
+		if v.IsDefault() {
+			return &mojom_types.DefaultFieldValueDefaultKeyword{mojom_types.DefaultKeyword{}}
+		}
+		return &mojom_types.DefaultFieldValueValue{translateLiteralValue(v)}
+	case *mojom.UserValueRef:
+		switch t := v.ResolvedConcreteValue().(type) {
+		case mojom.BuiltInConstantValue:
+			return &mojom_types.DefaultFieldValueValue{translateBuiltInConstantValue(t)}
+		default:
+			return &mojom_types.DefaultFieldValueValue{translateUserValueRef(v)}
+		}
+	default:
+		panic(fmt.Sprintf("Unexpected ValueRef type: %T", v))
+
+	}
+}
+
+func translateMojomInterface(intrfc *mojom.MojomInterface) *mojom_types.UserDefinedTypeInterfaceType {
+	mojomInterface := mojom_types.UserDefinedTypeInterfaceType{}
+
+	mojomInterface.Value.DeclData = translateDeclarationData(&intrfc.DeclarationData)
+	mojomInterface.Value.DeclData.ContainedDeclarations = translateContainedDeclarations(&intrfc.DeclarationContainer)
+
+	// TODO(rudominer) The Interface name field need not be the name from the .mojom file.
+	mojomInterface.Value.InterfaceName = intrfc.SimpleName()
+
+	mojomInterface.Value.Methods = make(map[uint32]mojom_types.MojomMethod)
+	for ordinal, method := range intrfc.MethodsByOrdinal {
+		mojomInterface.Value.Methods[ordinal] = translateMojomMethod(method)
+	}
+
+	return &mojomInterface
+}
+
+func translateMojomMethod(method *mojom.MojomMethod) mojom_types.MojomMethod {
+	mojomMethod := mojom_types.MojomMethod{}
+
+	// decl_data
+	mojomMethod.DeclData = translateDeclarationData(&method.DeclarationData)
+
+	// parameters
+	mojomMethod.Parameters = translateMojomStruct(method.Parameters)
+
+	// response_params
+	if method.ResponseParameters != nil {
+		responseParams := translateMojomStruct(method.ResponseParameters)
+		mojomMethod.ResponseParams = &responseParams
+	}
+
+	// ordinal
+	mojomMethod.Ordinal = method.Ordinal
+	return mojomMethod
+}
+
+func translateMojomEnum(enum *mojom.MojomEnum) *mojom_types.UserDefinedTypeEnumType {
+	mojomEnum := mojom_types.UserDefinedTypeEnumType{}
+	mojomEnum.Value.DeclData = translateDeclarationData(&enum.DeclarationData)
+	for _, value := range enum.Values {
+		mojomEnum.Value.Values = append(mojomEnum.Value.Values, translateEnumValue(value))
+	}
+	return &mojomEnum
+}
+
+func translateMojomUnion(union *mojom.MojomUnion) *mojom_types.UserDefinedTypeUnionType {
+	mojomUnion := mojom_types.UserDefinedTypeUnionType{}
+	mojomUnion.Value.DeclData = translateDeclarationData(&union.DeclarationData)
+	for _, field := range union.Fields {
+		mojomUnion.Value.Fields = append(mojomUnion.Value.Fields,
+			translateUnionField(field))
+	}
+	return &mojomUnion
+}
+
+func translateUnionField(unionField mojom.UnionField) mojom_types.UnionField {
+	outUnionField := mojom_types.UnionField{}
+	outUnionField.DeclData = translateDeclarationData(&unionField.DeclarationData)
+	outUnionField.Type = translateTypeRef(unionField.FieldType)
+	outUnionField.Tag = unionField.Tag
+	return outUnionField
+}
+
+// WARNING: Do not invoke this function on a UserDefinedValue of type BuiltInConstantValue because
+// objects of those types do not have a type_key and do not correspond to a mojom_types.UserDefinedValue.
+func translateUserDefinedValue(v mojom.UserDefinedValue) mojom_types.UserDefinedValue {
+	switch t := v.(type) {
+	case *mojom.UserDefinedConstant:
+		return translateUserDefinedConstant(t)
+	case *mojom.EnumValue:
+		return &mojom_types.UserDefinedValueEnumValue{translateEnumValue(t)}
+	case *mojom.BuiltInConstantValue:
+		panic("Do not invoke translateUserDefinedValue on BuiltInConstantValue.")
+	default:
+		panic(fmt.Sprintf("Unexpected UserDefinedValue type %T", v))
+
+	}
+}
+
+func translateUserDefinedConstant(t *mojom.UserDefinedConstant) *mojom_types.UserDefinedValueDeclaredConstant {
+	declaredConstant := mojom_types.UserDefinedValueDeclaredConstant{}
+	declaredConstant.Value.Type = translateTypeRef(t.DeclaredType())
+	declaredConstant.Value.DeclData = *translateDeclarationData(&t.DeclarationData)
+	declaredConstant.Value.Value = translateValueRef(t.ValueRef())
+	return &declaredConstant
+}
+
+func translateEnumValue(v *mojom.EnumValue) mojom_types.EnumValue {
+	enumValue := mojom_types.EnumValue{}
+	enumValue.DeclData = translateDeclarationData(&v.DeclarationData)
+	enumValue.EnumTypeKey = v.EnumType().TypeKey()
+	if v.ValueRef() != nil {
+		enumValue.InitializerValue = translateValueRef(v.ValueRef())
+	}
+	// TODO(rudominer) enumValue.IntValue should be set to v.ComputedIntValue
+	// once MojomDescriptor.ComputeEnumValueIntegers() is implemented.
+	enumValue.IntValue = v.Int32Value()
+	return enumValue
+}
+
+func translateTypeRef(typeRef mojom.TypeRef) mojom_types.Type {
+	switch t := typeRef.(type) {
+	case mojom.SimpleType:
+		return translateSimpleType(t)
+	case mojom.StringType:
+		return translateStringType(t)
+	case mojom.HandleTypeRef:
+		return translateHandleType(t)
+	case mojom.ArrayTypeRef:

[azani, 2015/11/10 22:46:07]

AFAICT, from running this code, you should expect *mojom.ArrayTypeRef. Same for
at least mojom.MapTypeRef and potentially others.

[rudominer, 2015/11/10 23:29:36]

OK, thanks for testing it. I will fix in a follow-up cl.

+		return translateArrayType(t)
+	case mojom.MapTypeRef:
+		return translateMapType(t)
+	case *mojom.UserTypeRef:
+		return translateUserTypeRef(t)
+	default:
+		panic(fmt.Sprintf("Unexpected TypeRef type %T", t))
+	}
+}
+
+func translateSimpleType(simpleType mojom.SimpleType) *mojom_types.TypeSimpleType {
+	var value mojom_types.SimpleType
+	switch simpleType {
+	case mojom.SimpleTypeBool:
+		value = mojom_types.SimpleType_Bool
+	case mojom.SimpleTypeDouble:
+		value = mojom_types.SimpleType_Double
+	case mojom.SimpleTypeFloat:
+		value = mojom_types.SimpleType_Float
+	case mojom.SimpleTypeInt8:
+		value = mojom_types.SimpleType_InT8
+	case mojom.SimpleTypeInt16:
+		value = mojom_types.SimpleType_InT16
+	case mojom.SimpleTypeInt32:
+		value = mojom_types.SimpleType_InT32
+	case mojom.SimpleTypeInt64:
+		value = mojom_types.SimpleType_InT64
+	case mojom.SimpleTypeUInt8:
+		value = mojom_types.SimpleType_UinT8
+	case mojom.SimpleTypeUInt16:
+		value = mojom_types.SimpleType_UinT16
+	case mojom.SimpleTypeUInt32:
+		value = mojom_types.SimpleType_UinT32
+	case mojom.SimpleTypeUInt64:
+		value = mojom_types.SimpleType_UinT64
+	}
+	return &mojom_types.TypeSimpleType{value}
+}
+
+func translateStringType(stringType mojom.StringType) *mojom_types.TypeStringType {
+	return &mojom_types.TypeStringType{mojom_types.StringType{stringType.Nullable()}}
+}
+
+func translateHandleType(handleType mojom.HandleTypeRef) *mojom_types.TypeHandleType {
+	var kind mojom_types.HandleType_Kind
+	switch handleType.HandleKind() {
+	case mojom.HandleKindUnspecified:
+		kind = mojom_types.HandleType_Kind_Unspecified
+	case mojom.HandleKindMessagePipe:
+		kind = mojom_types.HandleType_Kind_MessagePipe
+	case mojom.HandleKindDataPipeConsumer:
+		kind = mojom_types.HandleType_Kind_DataPipeConsumer
+	case mojom.HandleKindDataPipeProducer:
+		kind = mojom_types.HandleType_Kind_DataPipeProducer
+	case mojom.HandleKindSharedBuffer:
+		kind = mojom_types.HandleType_Kind_SharedBuffer
+	}
+	return &mojom_types.TypeHandleType{mojom_types.HandleType{handleType.Nullable(), kind}}
+}
+
+func translateArrayType(arrayType mojom.ArrayTypeRef) *mojom_types.TypeArrayType {
+	return &mojom_types.TypeArrayType{mojom_types.ArrayType{
+		Nullable:    arrayType.Nullable(),
+		FixedLength: int32(arrayType.FixedLength()),
+		ElementType: translateTypeRef(arrayType.ElementType())}}
+}
+
+func translateMapType(mapType mojom.MapTypeRef) *mojom_types.TypeMapType {
+	return &mojom_types.TypeMapType{mojom_types.MapType{
+		Nullable:  mapType.Nullable(),
+		KeyType:   translateTypeRef(mapType.KeyType()),
+		ValueType: translateTypeRef(mapType.ValueType())}}
+}
+
+func translateUserTypeRef(userType *mojom.UserTypeRef) *mojom_types.TypeTypeReference {
+	typeKey := newString(userType.ResolvedType().TypeKey())
+	identifier := newString(userType.Identifier())
+	return &mojom_types.TypeTypeReference{mojom_types.TypeReference{
+		Nullable:           userType.Nullable(),
+		IsInterfaceRequest: userType.IsInterfaceRequest(),
+		Identifier:         identifier,
+		TypeKey:            typeKey}}
+}
+
+func translateValueRef(valueRef mojom.ValueRef) mojom_types.Value {
+	switch valueRef := valueRef.(type) {
+	case mojom.LiteralValue:
+		return translateLiteralValue(valueRef)
+	case *mojom.UserValueRef:
+		return translateUserValueRef(valueRef)
+	default:
+		panic(fmt.Sprintf("Unexpected ValueRef type %T", valueRef))
+	}
+}
+
+func translateLiteralValue(v mojom.LiteralValue) *mojom_types.ValueLiteralValue {
+	var lv mojom_types.LiteralValue
+	switch v.ValueType() {
+	case mojom.SimpleTypeBool:
+		lv = &mojom_types.LiteralValueBoolValue{v.Value().(bool)}
+	case mojom.SimpleTypeDouble:
+		lv = &mojom_types.LiteralValueDoubleValue{v.Value().(float64)}
+	case mojom.SimpleTypeFloat:
+		lv = &mojom_types.LiteralValueFloatValue{v.Value().(float32)}
+	case mojom.SimpleTypeInt8:
+		lv = &mojom_types.LiteralValueInt8Value{v.Value().(int8)}
+	case mojom.SimpleTypeInt16:
+		lv = &mojom_types.LiteralValueInt16Value{v.Value().(int16)}
+	case mojom.SimpleTypeInt32:
+		lv = &mojom_types.LiteralValueInt32Value{v.Value().(int32)}
+	case mojom.SimpleTypeInt64:
+		lv = &mojom_types.LiteralValueInt64Value{v.Value().(int64)}
+	case mojom.SimpleTypeUInt8:
+		lv = &mojom_types.LiteralValueUint8Value{v.Value().(uint8)}
+	case mojom.SimpleTypeUInt16:
+		lv = &mojom_types.LiteralValueUint16Value{v.Value().(uint16)}
+	case mojom.SimpleTypeUInt32:
+		lv = &mojom_types.LiteralValueUint32Value{v.Value().(uint32)}
+	case mojom.SimpleTypeUInt64:
+		lv = &mojom_types.LiteralValueUint64Value{v.Value().(uint64)}
+	case mojom.StringLiteralType:
+		lv = &mojom_types.LiteralValueStringValue{v.Value().(string)}
+	default:
+		panic(fmt.Sprintf("Unexpected literal value type %d", v.ValueType()))
+	}
+	return &mojom_types.ValueLiteralValue{lv}
+}
+
+func translateBuiltInConstantValue(t mojom.BuiltInConstantValue) *mojom_types.ValueBuiltinValue {
+	builtInValue := mojom_types.ValueBuiltinValue{}
+	switch t {
+	case mojom.SimpleTypeFloat_INFINITY:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_FloatInfinity
+	case mojom.SimpleTypeFloat_NEGATIVE_INFINITY:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_FloatNegativeInfinity
+	case mojom.SimpleTypeFloat_NAN:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_FloatNan
+	case mojom.SimpleTypeDouble_INFINITY:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_DoubleInfinity
+	case mojom.SimpleTypeDouble_NEGATIVE_INFINITY:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_DoubleNegativeInfinity
+	case mojom.SimpleTypeDouble_NAN:
+		builtInValue.Value = mojom_types.BuiltinConstantValue_DoubleNegativeInfinity
+	default:
+		panic(fmt.Sprintf("Unrecognized BuiltInConstantValue %v", t))
+	}
+	return &builtInValue
+}
+
+func translateUserValueRef(r *mojom.UserValueRef) *mojom_types.ValueUserValueReference {
+	valueKey := newString(r.ResolvedDeclaredValue().ValueKey())
+	return &mojom_types.ValueUserValueReference{mojom_types.UserValueReference{
+		Identifier:            r.Identifier(),
+		ValueKey:              valueKey,
+		ResolvedConcreteValue: translateConcreteValue(r.ResolvedConcreteValue())}}
+}
+
+func translateConcreteValue(v mojom.ConcreteValue) mojom_types.Value {
+	switch t := v.(type) {
+	case mojom.BuiltInConstantValue:
+		return translateBuiltInConstantValue(t)
+	case mojom.LiteralValue:
+		return translateLiteralValue(t)
+	case *mojom.EnumValue:
+		// Note that in the pure Go representation we support the abstraction
+		// that an EnumValue is a type of ConcreteValue. This makes sense because
+		// an Enum is abstractly a finite set of values that need not have
+		// a corresponding integer value. However in mojom_types.mojom we currently
+		// do not support this abstraction: the only concrete values are the literal
+		// values and the BuiltInConstantValues. Consequently here we return the
+		// Int32Value() of the EnumValue.
+		return &mojom_types.ValueLiteralValue{&mojom_types.LiteralValueInt32Value{t.Int32Value()}}
+	default:
+		panic(fmt.Sprintf("Unexpected type %T", v))
+	}
+}
+
+func translateDeclarationData(d *mojom.DeclarationData) *mojom_types.DeclarationData {
+	declData := mojom_types.DeclarationData{}
+
+	// attributes field
+	if d.Attributes() != nil {
+		declData.Attributes = new([]mojom_types.Attribute)
+		for _, attr := range d.Attributes().List {
+			*(declData.Attributes) = append(*(declData.Attributes), translateMojomAttribute(&attr))
+		}
+	}
+
+	// min_version field
+	// TODO(rudominer) Eliminate the min_version field from struct DeclarationData
+
+	// short_name field
+	declData.ShortName = newString(d.SimpleName())
+
+	// full_identifier field
+	declData.FullIdentifier = newString(d.FullyQualifiedName())
+
+	// declared_ordinal field
+	if d.DeclaredOrdinal() < 0 {
+		declData.DeclaredOrdinal = -1
+	} else {
+		declData.DeclaredOrdinal = int32(d.DeclaredOrdinal())
+	}
+
+	// declaration_order
+	// TODO(rudominer) DeclarationOrder is currently not populated.
+	declData.DeclarationOrder = -1
+
+	// source_file_info
+	declData.SourceFileInfo = new(mojom_types.SourceFileInfo)
+	declData.SourceFileInfo.FileName = d.OwningFile().CanonicalFileName
+	if EmitLineAndColumnNumbers {
+		declData.SourceFileInfo.LineNumber = d.LineNumber()
+		declData.SourceFileInfo.ColumnNumber = d.ColumnNumber()
+	}
+	return &declData
+}
+
+// Returns nil if there are no contained declarations
+func translateContainedDeclarations(container *mojom.DeclarationContainer) *mojom_types.ContainedDeclarations {
+	if container.Enums == nil && container.Constants == nil {
+		return nil
+	}
+	declarations := mojom_types.ContainedDeclarations{}
+	if container.Enums != nil {
+		declarations.Enums = new([]string)
+		for _, enum := range container.Enums {
+			*declarations.Enums = append(*declarations.Enums, enum.TypeKey())
+		}
+	}
+	if container.Constants != nil {
+		declarations.Constants = new([]string)
+		for _, constant := range container.Constants {
+			*declarations.Constants = append(*declarations.Constants, constant.ValueKey())
+		}
+	}
+	return &declarations
+}
+
+func translateMojomAttribute(a *mojom.MojomAttribute) (attribute mojom_types.Attribute) {
+	// TODO(rudominer) Improve representation of attribute values.
+	return mojom_types.Attribute{a.Key, fmt.Sprintf("%v", a.Value.Value())}
+}
+
+func newString(s string) *string {

[mattr, 2015/11/10 19:26:49]

I don't understand this function.  In Go strings are immutable so it shouldn't
be necessary to copy, and actually what you are doing is not copying but
creating a new string header only.  What are you actually trying to accomplish?

[rudominer, 2015/11/10 23:29:36]

The explanation for this peculiarity is similar to the previous one.

I added the following comment to clarify:
// newString is a convenience function for creating a pointer to a 
// string whose value  is the specified string. It is necessary to 
// create pointers to strings because that is how the Mojom type |string?| 
// (i.e. nullable string) is represented in the Mojom Go bindings.

[mattr, 2015/11/10 23:43:40]

Sure, but you should just do 

return &s

In which case there is really no need for the function.

+	t := new(string)
+	*t = s
+	return t
+}