internal/impl/legacy_message.go - protobuf - Git at Google

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package impl

 import (
 	"fmt"
 	"reflect"
 	"strings"
 	"sync"

 	"google.golang.org/protobuf/internal/descopts"
 	ptag "google.golang.org/protobuf/internal/encoding/tag"
 	"google.golang.org/protobuf/internal/filedesc"
 	"google.golang.org/protobuf/internal/strs"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 )

 // legacyWrapMessage wraps v as a protoreflect.ProtoMessage,
 // where v must be a *struct kind and not implement the v2 API already.
 func legacyWrapMessage(v reflect.Value) pref.ProtoMessage {
 	mt := legacyLoadMessageInfo(v.Type())
 	return mt.MessageOf(v.Interface()).Interface()
 }

 var legacyMessageTypeCache sync.Map // map[reflect.Type]*MessageInfo

 // legacyLoadMessageInfo dynamically loads a *MessageInfo for t,
 // where t must be a *struct kind and not implement the v2 API already.
 func legacyLoadMessageInfo(t reflect.Type) *MessageInfo {
 	// Fast-path: check if a MessageInfo is cached for this concrete type.
 	if mt, ok := legacyMessageTypeCache.Load(t); ok {
 		return mt.(*MessageInfo)
 	}

 	// Slow-path: derive message descriptor and initialize MessageInfo.
 	mi := &MessageInfo{
 		Desc:          LegacyLoadMessageDesc(t),
 		GoReflectType: t,
 	}
 	if mi, ok := legacyMessageTypeCache.LoadOrStore(t, mi); ok {
 		return mi.(*MessageInfo)
 	}
 	return mi
 }

 var legacyMessageDescCache sync.Map // map[reflect.Type]protoreflect.MessageDescriptor

 // LegacyLoadMessageDesc returns an MessageDescriptor derived from the Go type,
 // which must be a *struct kind and not implement the v2 API already.
 //
 // This is exported for testing purposes.
 func LegacyLoadMessageDesc(t reflect.Type) pref.MessageDescriptor {
 	// Fast-path: check if a MessageDescriptor is cached for this concrete type.
 	if mi, ok := legacyMessageDescCache.Load(t); ok {
 		return mi.(pref.MessageDescriptor)
 	}

 	// Slow-path: initialize MessageDescriptor from the raw descriptor.
 	mv := reflect.New(t.Elem()).Interface()
 	if _, ok := mv.(pref.ProtoMessage); ok {
 		panic(fmt.Sprintf("%v already implements proto.Message", t))
 	}
 	mdV1, ok := mv.(messageV1)
 	if !ok {
 		return aberrantLoadMessageDesc(t)
 	}
 	b, idxs := mdV1.Descriptor()

 	md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
 	for _, i := range idxs[1:] {
 		md = md.Messages().Get(i)
 	}
 	if md, ok := legacyMessageDescCache.LoadOrStore(t, md); ok {
 		return md.(protoreflect.MessageDescriptor)
 	}
 	return md
 }

 var (
 	aberrantMessageDescLock  sync.Mutex
 	aberrantMessageDescCache map[reflect.Type]protoreflect.MessageDescriptor
 )

 // aberrantLoadMessageDesc returns an EnumDescriptor derived from the Go type,
 // which must not implement protoreflect.ProtoMessage or messageV1.
 //
 // This is a best-effort derivation of the message descriptor using the protobuf
 // tags on the struct fields.
 func aberrantLoadMessageDesc(t reflect.Type) pref.MessageDescriptor {
 	aberrantMessageDescLock.Lock()
 	defer aberrantMessageDescLock.Unlock()
 	if aberrantMessageDescCache == nil {
 		aberrantMessageDescCache = make(map[reflect.Type]protoreflect.MessageDescriptor)
 	}
 	return aberrantLoadMessageDescReentrant(t)
 }
 func aberrantLoadMessageDescReentrant(t reflect.Type) pref.MessageDescriptor {
 	// Fast-path: check if an MessageDescriptor is cached for this concrete type.
 	if md, ok := aberrantMessageDescCache[t]; ok {
 		return md
 	}

 	// Slow-path: construct a descriptor from the Go struct type (best-effort).
 	// Cache the MessageDescriptor early on so that we can resolve internal
 	// cyclic references.
 	md := &filedesc.Message{L2: new(filedesc.MessageL2)}
 	md.L0.FullName = aberrantDeriveFullName(t.Elem())
 	md.L0.ParentFile = filedesc.SurrogateProto2
 	aberrantMessageDescCache[t] = md

 	// Try to determine if the message is using proto3 by checking scalars.
 	for i := 0; i < t.Elem().NumField(); i++ {
 		f := t.Elem().Field(i)
 		if tag := f.Tag.Get("protobuf"); tag != "" {
 			switch f.Type.Kind() {
 			case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
 				md.L0.ParentFile = filedesc.SurrogateProto3
 			}
 			for _, s := range strings.Split(tag, ",") {
 				if s == "proto3" {
 					md.L0.ParentFile = filedesc.SurrogateProto3
 				}
 			}
 		}
 	}

 	// Obtain a list of oneof wrapper types.
 	var oneofWrappers []reflect.Type
 	if fn, ok := t.MethodByName("XXX_OneofFuncs"); ok {
 		vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[3]
 		for _, v := range vs.Interface().([]interface{}) {
 			oneofWrappers = append(oneofWrappers, reflect.TypeOf(v))
 		}
 	}
 	if fn, ok := t.MethodByName("XXX_OneofWrappers"); ok {
 		vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[0]
 		for _, v := range vs.Interface().([]interface{}) {
 			oneofWrappers = append(oneofWrappers, reflect.TypeOf(v))
 		}
 	}

 	// Obtain a list of the extension ranges.
 	if fn, ok := t.MethodByName("ExtensionRangeArray"); ok {
 		vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[0]
 		for i := 0; i < vs.Len(); i++ {
 			v := vs.Index(i)
 			md.L2.ExtensionRanges.List = append(md.L2.ExtensionRanges.List, [2]pref.FieldNumber{
 				pref.FieldNumber(v.FieldByName("Start").Int()),
 				pref.FieldNumber(v.FieldByName("End").Int() + 1),
 			})
 			md.L2.ExtensionRangeOptions = append(md.L2.ExtensionRangeOptions, nil)
 		}
 	}

 	// Derive the message fields by inspecting the struct fields.
 	for i := 0; i < t.Elem().NumField(); i++ {
 		f := t.Elem().Field(i)
 		if tag := f.Tag.Get("protobuf"); tag != "" {
 			tagKey := f.Tag.Get("protobuf_key")
 			tagVal := f.Tag.Get("protobuf_val")
 			aberrantAppendField(md, f.Type, tag, tagKey, tagVal)
 		}
 		if tag := f.Tag.Get("protobuf_oneof"); tag != "" {
 			n := len(md.L2.Oneofs.List)
 			md.L2.Oneofs.List = append(md.L2.Oneofs.List, filedesc.Oneof{})
 			od := &md.L2.Oneofs.List[n]
 			od.L0.FullName = md.FullName().Append(pref.Name(tag))
 			od.L0.ParentFile = md.L0.ParentFile
 			od.L0.Parent = md
 			od.L0.Index = n

 			for _, t := range oneofWrappers {
 				if t.Implements(f.Type) {
 					f := t.Elem().Field(0)
 					if tag := f.Tag.Get("protobuf"); tag != "" {
 						aberrantAppendField(md, f.Type, tag, "", "")
 						fd := &md.L2.Fields.List[len(md.L2.Fields.List)-1]
 						fd.L1.ContainingOneof = od
 						od.L1.Fields.List = append(od.L1.Fields.List, fd)
 					}
 				}
 			}
 		}
 	}

 	// TODO: Use custom Marshal/Unmarshal methods for the fast-path?

 	return md
 }

 func aberrantAppendField(md *filedesc.Message, goType reflect.Type, tag, tagKey, tagVal string) {
 	t := goType
 	isOptional := t.Kind() == reflect.Ptr && t.Elem().Kind() != reflect.Struct
 	isRepeated := t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8
 	if isOptional || isRepeated {
 		t = t.Elem()
 	}
 	fd := ptag.Unmarshal(tag, t, placeholderEnumValues{}).(*filedesc.Field)

 	// Append field descriptor to the message.
 	n := len(md.L2.Fields.List)
 	md.L2.Fields.List = append(md.L2.Fields.List, *fd)
 	fd = &md.L2.Fields.List[n]
 	fd.L0.FullName = md.FullName().Append(fd.Name())
 	fd.L0.ParentFile = md.L0.ParentFile
 	fd.L0.Parent = md
 	fd.L0.Index = n

 	if fd.L1.IsWeak || fd.L1.HasPacked {
 		fd.L1.Options = func() pref.ProtoMessage {
 			opts := descopts.Field.ProtoReflect().New()
 			if fd.L1.IsWeak {
 				opts.Set(opts.Descriptor().Fields().ByName("weak"), protoreflect.ValueOf(true))
 			}
 			if fd.L1.HasPacked {
 				opts.Set(opts.Descriptor().Fields().ByName("packed"), protoreflect.ValueOf(fd.L1.IsPacked))
 			}
 			return opts.Interface()
 		}
 	}

 	// Populate Enum and Message.
 	if fd.Enum() == nil && fd.Kind() == pref.EnumKind {
 		switch v := reflect.Zero(t).Interface().(type) {
 		case pref.Enum:
 			fd.L1.Enum = v.Descriptor()
 		default:
 			fd.L1.Enum = LegacyLoadEnumDesc(t)
 		}
 	}
 	if fd.Message() == nil && (fd.Kind() == pref.MessageKind || fd.Kind() == pref.GroupKind) {
 		switch v := reflect.Zero(t).Interface().(type) {
 		case pref.ProtoMessage:
 			fd.L1.Message = v.ProtoReflect().Descriptor()
 		case messageV1:
 			fd.L1.Message = LegacyLoadMessageDesc(t)
 		default:
 			if t.Kind() == reflect.Map {
 				n := len(md.L1.Messages.List)
 				md.L1.Messages.List = append(md.L1.Messages.List, filedesc.Message{L2: new(filedesc.MessageL2)})
 				md2 := &md.L1.Messages.List[n]
 				md2.L0.FullName = md.FullName().Append(pref.Name(strs.MapEntryName(string(fd.Name()))))
 				md2.L0.ParentFile = md.L0.ParentFile
 				md2.L0.Parent = md
 				md2.L0.Index = n

 				md2.L2.IsMapEntry = true
 				md2.L2.Options = func() pref.ProtoMessage {
 					opts := descopts.Message.ProtoReflect().New()
 					opts.Set(opts.Descriptor().Fields().ByName("map_entry"), protoreflect.ValueOf(true))
 					return opts.Interface()
 				}

 				aberrantAppendField(md2, t.Key(), tagKey, "", "")
 				aberrantAppendField(md2, t.Elem(), tagVal, "", "")

 				fd.L1.Message = md2
 				break
 			}
 			fd.L1.Message = aberrantLoadMessageDescReentrant(t)
 		}
 	}
 }

 type placeholderEnumValues struct {
 	protoreflect.EnumValueDescriptors
 }

 func (placeholderEnumValues) ByNumber(n pref.EnumNumber) pref.EnumValueDescriptor {
 	return filedesc.PlaceholderEnumValue(pref.FullName(fmt.Sprintf("UNKNOWN_%d", n)))
 }
	// Copyright 2018 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package impl

	import (
	"fmt"
	"reflect"
	"strings"
	"sync"

	"google.golang.org/protobuf/internal/descopts"
	ptag "google.golang.org/protobuf/internal/encoding/tag"
	"google.golang.org/protobuf/internal/filedesc"
	"google.golang.org/protobuf/internal/strs"
	"google.golang.org/protobuf/reflect/protoreflect"
	pref "google.golang.org/protobuf/reflect/protoreflect"
	)

	// legacyWrapMessage wraps v as a protoreflect.ProtoMessage,
	// where v must be a *struct kind and not implement the v2 API already.
	func legacyWrapMessage(v reflect.Value) pref.ProtoMessage {
	mt := legacyLoadMessageInfo(v.Type())
	return mt.MessageOf(v.Interface()).Interface()
	}

	var legacyMessageTypeCache sync.Map // map[reflect.Type]*MessageInfo

	// legacyLoadMessageInfo dynamically loads a *MessageInfo for t,
	// where t must be a *struct kind and not implement the v2 API already.
	func legacyLoadMessageInfo(t reflect.Type) *MessageInfo {
	// Fast-path: check if a MessageInfo is cached for this concrete type.
	if mt, ok := legacyMessageTypeCache.Load(t); ok {
	return mt.(*MessageInfo)
	}

	// Slow-path: derive message descriptor and initialize MessageInfo.
	mi := &MessageInfo{
	Desc: LegacyLoadMessageDesc(t),
	GoReflectType: t,
	}
	if mi, ok := legacyMessageTypeCache.LoadOrStore(t, mi); ok {
	return mi.(*MessageInfo)
	}
	return mi
	}

	var legacyMessageDescCache sync.Map // map[reflect.Type]protoreflect.MessageDescriptor

	// LegacyLoadMessageDesc returns an MessageDescriptor derived from the Go type,
	// which must be a *struct kind and not implement the v2 API already.
	//
	// This is exported for testing purposes.
	func LegacyLoadMessageDesc(t reflect.Type) pref.MessageDescriptor {
	// Fast-path: check if a MessageDescriptor is cached for this concrete type.
	if mi, ok := legacyMessageDescCache.Load(t); ok {
	return mi.(pref.MessageDescriptor)
	}

	// Slow-path: initialize MessageDescriptor from the raw descriptor.
	mv := reflect.New(t.Elem()).Interface()
	if _, ok := mv.(pref.ProtoMessage); ok {
	panic(fmt.Sprintf("%v already implements proto.Message", t))
	}
	mdV1, ok := mv.(messageV1)
	if !ok {
	return aberrantLoadMessageDesc(t)
	}
	b, idxs := mdV1.Descriptor()

	md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
	for _, i := range idxs[1:] {
	md = md.Messages().Get(i)
	}
	if md, ok := legacyMessageDescCache.LoadOrStore(t, md); ok {
	return md.(protoreflect.MessageDescriptor)
	}
	return md
	}

	var (
	aberrantMessageDescLock sync.Mutex
	aberrantMessageDescCache map[reflect.Type]protoreflect.MessageDescriptor
	)

	// aberrantLoadMessageDesc returns an EnumDescriptor derived from the Go type,
	// which must not implement protoreflect.ProtoMessage or messageV1.
	//
	// This is a best-effort derivation of the message descriptor using the protobuf
	// tags on the struct fields.
	func aberrantLoadMessageDesc(t reflect.Type) pref.MessageDescriptor {
	aberrantMessageDescLock.Lock()
	defer aberrantMessageDescLock.Unlock()
	if aberrantMessageDescCache == nil {
	aberrantMessageDescCache = make(map[reflect.Type]protoreflect.MessageDescriptor)
	}
	return aberrantLoadMessageDescReentrant(t)
	}
	func aberrantLoadMessageDescReentrant(t reflect.Type) pref.MessageDescriptor {
	// Fast-path: check if an MessageDescriptor is cached for this concrete type.
	if md, ok := aberrantMessageDescCache[t]; ok {
	return md
	}

	// Slow-path: construct a descriptor from the Go struct type (best-effort).
	// Cache the MessageDescriptor early on so that we can resolve internal
	// cyclic references.
	md := &filedesc.Message{L2: new(filedesc.MessageL2)}
	md.L0.FullName = aberrantDeriveFullName(t.Elem())
	md.L0.ParentFile = filedesc.SurrogateProto2
	aberrantMessageDescCache[t] = md

	// Try to determine if the message is using proto3 by checking scalars.
	for i := 0; i < t.Elem().NumField(); i++ {
	f := t.Elem().Field(i)
	if tag := f.Tag.Get("protobuf"); tag != "" {
	switch f.Type.Kind() {
	case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
	md.L0.ParentFile = filedesc.SurrogateProto3
	}
	for _, s := range strings.Split(tag, ",") {
	if s == "proto3" {
	md.L0.ParentFile = filedesc.SurrogateProto3
	}
	}
	}
	}

	// Obtain a list of oneof wrapper types.
	var oneofWrappers []reflect.Type
	if fn, ok := t.MethodByName("XXX_OneofFuncs"); ok {
	vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[3]
	for _, v := range vs.Interface().([]interface{}) {
	oneofWrappers = append(oneofWrappers, reflect.TypeOf(v))
	}
	}
	if fn, ok := t.MethodByName("XXX_OneofWrappers"); ok {
	vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[0]
	for _, v := range vs.Interface().([]interface{}) {
	oneofWrappers = append(oneofWrappers, reflect.TypeOf(v))
	}
	}

	// Obtain a list of the extension ranges.
	if fn, ok := t.MethodByName("ExtensionRangeArray"); ok {
	vs := fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[0]
	for i := 0; i < vs.Len(); i++ {
	v := vs.Index(i)
	md.L2.ExtensionRanges.List = append(md.L2.ExtensionRanges.List, [2]pref.FieldNumber{
	pref.FieldNumber(v.FieldByName("Start").Int()),
	pref.FieldNumber(v.FieldByName("End").Int() + 1),
	})
	md.L2.ExtensionRangeOptions = append(md.L2.ExtensionRangeOptions, nil)
	}
	}

	// Derive the message fields by inspecting the struct fields.
	for i := 0; i < t.Elem().NumField(); i++ {
	f := t.Elem().Field(i)
	if tag := f.Tag.Get("protobuf"); tag != "" {
	tagKey := f.Tag.Get("protobuf_key")
	tagVal := f.Tag.Get("protobuf_val")
	aberrantAppendField(md, f.Type, tag, tagKey, tagVal)
	}
	if tag := f.Tag.Get("protobuf_oneof"); tag != "" {
	n := len(md.L2.Oneofs.List)
	md.L2.Oneofs.List = append(md.L2.Oneofs.List, filedesc.Oneof{})
	od := &md.L2.Oneofs.List[n]
	od.L0.FullName = md.FullName().Append(pref.Name(tag))
	od.L0.ParentFile = md.L0.ParentFile
	od.L0.Parent = md
	od.L0.Index = n

	for _, t := range oneofWrappers {
	if t.Implements(f.Type) {
	f := t.Elem().Field(0)
	if tag := f.Tag.Get("protobuf"); tag != "" {
	aberrantAppendField(md, f.Type, tag, "", "")
	fd := &md.L2.Fields.List[len(md.L2.Fields.List)-1]
	fd.L1.ContainingOneof = od
	od.L1.Fields.List = append(od.L1.Fields.List, fd)
	}
	}
	}
	}
	}

	// TODO: Use custom Marshal/Unmarshal methods for the fast-path?

	return md
	}

	func aberrantAppendField(md *filedesc.Message, goType reflect.Type, tag, tagKey, tagVal string) {
	t := goType
	isOptional := t.Kind() == reflect.Ptr && t.Elem().Kind() != reflect.Struct
	isRepeated := t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8
	if isOptional \|\| isRepeated {
	t = t.Elem()
	}
	fd := ptag.Unmarshal(tag, t, placeholderEnumValues{}).(*filedesc.Field)

	// Append field descriptor to the message.
	n := len(md.L2.Fields.List)
	md.L2.Fields.List = append(md.L2.Fields.List, *fd)
	fd = &md.L2.Fields.List[n]
	fd.L0.FullName = md.FullName().Append(fd.Name())
	fd.L0.ParentFile = md.L0.ParentFile
	fd.L0.Parent = md
	fd.L0.Index = n

	if fd.L1.IsWeak \|\| fd.L1.HasPacked {
	fd.L1.Options = func() pref.ProtoMessage {
	opts := descopts.Field.ProtoReflect().New()
	if fd.L1.IsWeak {
	opts.Set(opts.Descriptor().Fields().ByName("weak"), protoreflect.ValueOf(true))
	}
	if fd.L1.HasPacked {
	opts.Set(opts.Descriptor().Fields().ByName("packed"), protoreflect.ValueOf(fd.L1.IsPacked))
	}
	return opts.Interface()
	}
	}

	// Populate Enum and Message.
	if fd.Enum() == nil && fd.Kind() == pref.EnumKind {
	switch v := reflect.Zero(t).Interface().(type) {
	case pref.Enum:
	fd.L1.Enum = v.Descriptor()
	default:
	fd.L1.Enum = LegacyLoadEnumDesc(t)
	}
	}
	if fd.Message() == nil && (fd.Kind() == pref.MessageKind \|\| fd.Kind() == pref.GroupKind) {
	switch v := reflect.Zero(t).Interface().(type) {
	case pref.ProtoMessage:
	fd.L1.Message = v.ProtoReflect().Descriptor()
	case messageV1:
	fd.L1.Message = LegacyLoadMessageDesc(t)
	default:
	if t.Kind() == reflect.Map {
	n := len(md.L1.Messages.List)
	md.L1.Messages.List = append(md.L1.Messages.List, filedesc.Message{L2: new(filedesc.MessageL2)})
	md2 := &md.L1.Messages.List[n]
	md2.L0.FullName = md.FullName().Append(pref.Name(strs.MapEntryName(string(fd.Name()))))
	md2.L0.ParentFile = md.L0.ParentFile
	md2.L0.Parent = md
	md2.L0.Index = n

	md2.L2.IsMapEntry = true
	md2.L2.Options = func() pref.ProtoMessage {
	opts := descopts.Message.ProtoReflect().New()
	opts.Set(opts.Descriptor().Fields().ByName("map_entry"), protoreflect.ValueOf(true))
	return opts.Interface()
	}

	aberrantAppendField(md2, t.Key(), tagKey, "", "")
	aberrantAppendField(md2, t.Elem(), tagVal, "", "")

	fd.L1.Message = md2
	break
	}
	fd.L1.Message = aberrantLoadMessageDescReentrant(t)
	}
	}
	}

	type placeholderEnumValues struct {
	protoreflect.EnumValueDescriptors
	}

	func (placeholderEnumValues) ByNumber(n pref.EnumNumber) pref.EnumValueDescriptor {
	return filedesc.PlaceholderEnumValue(pref.FullName(fmt.Sprintf("UNKNOWN_%d", n)))
	}