blob: ac96e71122a936b84d3f9ceabd24736e7819081c [file] [log] [blame]
// 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/errors"
"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"
piface "google.golang.org/protobuf/runtime/protoiface"
)
// 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 {
typ := v.Type()
if typ.Kind() != reflect.Ptr || typ.Elem().Kind() != reflect.Struct {
return aberrantMessage{v: v}
}
mt := legacyLoadMessageInfo(typ, "")
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.
// The provided name is used if it cannot be determined from the message.
func legacyLoadMessageInfo(t reflect.Type, name pref.FullName) *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, name),
GoReflectType: t,
}
v := reflect.Zero(t).Interface()
if _, ok := v.(legacyMarshaler); ok {
mi.methods.MarshalAppend = legacyMarshalAppend
// We have no way to tell whether the type's Marshal method
// supports deterministic serialization or not, but this
// preserves the v1 implementation's behavior of always
// calling Marshal methods when present.
mi.methods.Flags |= piface.SupportMarshalDeterministic
}
if _, ok := v.(legacyUnmarshaler); ok {
mi.methods.Unmarshal = legacyUnmarshal
}
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 {
return legacyLoadMessageDesc(t, "")
}
func legacyLoadMessageDesc(t reflect.Type, name pref.FullName) 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.Zero(t).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, name)
}
// If this is a dynamic message type where there isn't a 1-1 mapping between
// Go and protobuf types, calling the Descriptor method on the zero value of
// the message type isn't likely to work. If it panics, swallow the panic and
// continue as if the Descriptor method wasn't present.
b, idxs := func() ([]byte, []int) {
defer func() {
recover()
}()
return mdV1.Descriptor()
}()
if b == nil {
return aberrantLoadMessageDesc(t, name)
}
// If the Go type has no fields, then this might be a proto3 empty message
// from before the size cache was added. If there are any fields, check to
// see that at least one of them looks like something we generated.
if nfield := t.Elem().NumField(); nfield > 0 {
hasProtoField := false
for i := 0; i < nfield; i++ {
f := t.Elem().Field(i)
if f.Tag.Get("protobuf") != "" || f.Tag.Get("protobuf_oneof") != "" || strings.HasPrefix(f.Name, "XXX_") {
hasProtoField = true
break
}
}
if !hasProtoField {
return aberrantLoadMessageDesc(t, name)
}
}
md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
for _, i := range idxs[1:] {
md = md.Messages().Get(i)
}
if name != "" && md.FullName() != name {
panic(fmt.Sprintf("mismatching message name: got %v, want %v", md.FullName(), name))
}
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 MessageDescriptor 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, name pref.FullName) pref.MessageDescriptor {
aberrantMessageDescLock.Lock()
defer aberrantMessageDescLock.Unlock()
if aberrantMessageDescCache == nil {
aberrantMessageDescCache = make(map[reflect.Type]protoreflect.MessageDescriptor)
}
return aberrantLoadMessageDescReentrant(t, name)
}
func aberrantLoadMessageDescReentrant(t reflect.Type, name pref.FullName) 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 = aberrantDeriveMessageName(t, name)
md.L0.ParentFile = filedesc.SurrogateProto2
aberrantMessageDescCache[t] = md
if t.Kind() != reflect.Ptr || t.Elem().Kind() != reflect.Struct {
return 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)
}
}
}
}
}
return md
}
func aberrantDeriveMessageName(t reflect.Type, name pref.FullName) pref.FullName {
if name.IsValid() {
return name
}
func() {
defer func() { recover() }() // swallow possible nil panics
if m, ok := reflect.Zero(t).Interface().(interface{ XXX_MessageName() string }); ok {
name = pref.FullName(m.XXX_MessageName())
}
}()
if name.IsValid() {
return name
}
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
return aberrantDeriveFullName(t)
}
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.ValueOfBool(true))
}
if fd.L1.HasPacked {
opts.Set(opts.Descriptor().Fields().ByName("packed"), protoreflect.ValueOfBool(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.L1.IsMapEntry = true
md2.L2.Options = func() pref.ProtoMessage {
opts := descopts.Message.ProtoReflect().New()
opts.Set(opts.Descriptor().Fields().ByName("map_entry"), protoreflect.ValueOfBool(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)))
}
// legacyMarshaler is the proto.Marshaler interface superseded by protoiface.Methoder.
type legacyMarshaler interface {
Marshal() ([]byte, error)
}
// legacyUnmarshaler is the proto.Unmarshaler interface superseded by protoiface.Methoder.
type legacyUnmarshaler interface {
Unmarshal([]byte) error
}
var legacyProtoMethods = &piface.Methods{
MarshalAppend: legacyMarshalAppend,
Unmarshal: legacyUnmarshal,
// We have no way to tell whether the type's Marshal method
// supports deterministic serialization or not, but this
// preserves the v1 implementation's behavior of always
// calling Marshal methods when present.
Flags: piface.SupportMarshalDeterministic,
}
func legacyMarshalAppend(b []byte, m protoreflect.Message, opts piface.MarshalOptions) ([]byte, error) {
v := m.(unwrapper).protoUnwrap()
marshaler, ok := v.(legacyMarshaler)
if !ok {
return nil, errors.New("%T does not implement Marshal", v)
}
out, err := marshaler.Marshal()
if b != nil {
out = append(b, out...)
}
return out, err
}
func legacyUnmarshal(b []byte, m protoreflect.Message, opts piface.UnmarshalOptions) error {
v := m.(unwrapper).protoUnwrap()
unmarshaler, ok := v.(legacyUnmarshaler)
if !ok {
return errors.New("%T does not implement Marshal", v)
}
return unmarshaler.Unmarshal(b)
}
// aberrantMessageType implements MessageType for all types other than pointer-to-struct.
type aberrantMessageType struct {
t reflect.Type
}
func (mt aberrantMessageType) New() pref.Message {
return aberrantMessage{reflect.Zero(mt.t)}
}
func (mt aberrantMessageType) Zero() pref.Message {
return aberrantMessage{reflect.Zero(mt.t)}
}
func (mt aberrantMessageType) GoType() reflect.Type {
return mt.t
}
func (mt aberrantMessageType) Descriptor() pref.MessageDescriptor {
return LegacyLoadMessageDesc(mt.t)
}
// aberrantMessage implements Message for all types other than pointer-to-struct.
//
// When the underlying type implements legacyMarshaler or legacyUnmarshaler,
// the aberrant Message can be marshaled or unmarshaled. Otherwise, there is
// not much that can be done with values of this type.
type aberrantMessage struct {
v reflect.Value
}
func (m aberrantMessage) ProtoReflect() pref.Message {
return m
}
func (m aberrantMessage) Descriptor() pref.MessageDescriptor {
return LegacyLoadMessageDesc(m.v.Type())
}
func (m aberrantMessage) Type() pref.MessageType {
return aberrantMessageType{m.v.Type()}
}
func (m aberrantMessage) New() pref.Message {
return aberrantMessage{reflect.Zero(m.v.Type())}
}
func (m aberrantMessage) Interface() pref.ProtoMessage {
return m
}
func (m aberrantMessage) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
}
func (m aberrantMessage) Has(pref.FieldDescriptor) bool {
panic("invalid field descriptor")
}
func (m aberrantMessage) Clear(pref.FieldDescriptor) {
panic("invalid field descriptor")
}
func (m aberrantMessage) Get(pref.FieldDescriptor) pref.Value {
panic("invalid field descriptor")
}
func (m aberrantMessage) Set(pref.FieldDescriptor, pref.Value) {
panic("invalid field descriptor")
}
func (m aberrantMessage) Mutable(pref.FieldDescriptor) pref.Value {
panic("invalid field descriptor")
}
func (m aberrantMessage) NewField(pref.FieldDescriptor) pref.Value {
panic("invalid field descriptor")
}
func (m aberrantMessage) WhichOneof(pref.OneofDescriptor) pref.FieldDescriptor {
panic("invalid oneof descriptor")
}
func (m aberrantMessage) GetUnknown() pref.RawFields {
return nil
}
func (m aberrantMessage) SetUnknown(pref.RawFields) {
// SetUnknown discards its input on messages which don't support unknown field storage.
}
func (m aberrantMessage) IsValid() bool {
// An invalid message is a read-only, empty message. Since we don't know anything
// about the alleged contents of this message, we can't say with confidence that
// it is invalid in this sense. Therefore, report it as valid.
return true
}
func (m aberrantMessage) ProtoMethods() *piface.Methods {
return legacyProtoMethods
}
func (m aberrantMessage) protoUnwrap() interface{} {
return m.v.Interface()
}