| // 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" |
| "math" |
| "reflect" |
| "sync" |
| |
| descriptorV1 "github.com/golang/protobuf/protoc-gen-go/descriptor" |
| pref "github.com/golang/protobuf/v2/reflect/protoreflect" |
| ptype "github.com/golang/protobuf/v2/reflect/prototype" |
| ) |
| |
| var enumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor |
| |
| // loadEnumDesc returns an EnumDescriptor derived from the Go type, |
| // which must be an int32 kind and not implement the v2 API already. |
| func loadEnumDesc(t reflect.Type) pref.EnumDescriptor { |
| // Fast-path: check if an EnumDescriptor is cached for this concrete type. |
| if v, ok := enumDescCache.Load(t); ok { |
| return v.(pref.EnumDescriptor) |
| } |
| |
| // Slow-path: initialize EnumDescriptor from the proto descriptor. |
| if t.Kind() != reflect.Int32 { |
| panic(fmt.Sprintf("got %v, want int32 kind", t)) |
| } |
| |
| // Derive the enum descriptor from the raw descriptor proto. |
| e := new(ptype.StandaloneEnum) |
| ev := reflect.Zero(t).Interface() |
| if _, ok := ev.(pref.ProtoEnum); ok { |
| panic(fmt.Sprintf("%v already implements proto.Enum", t)) |
| } |
| if ed, ok := ev.(legacyEnum); ok { |
| b, idxs := ed.EnumDescriptor() |
| fd := loadFileDesc(b) |
| |
| // Derive syntax. |
| switch fd.GetSyntax() { |
| case "proto2", "": |
| e.Syntax = pref.Proto2 |
| case "proto3": |
| e.Syntax = pref.Proto3 |
| } |
| |
| // Derive the full name and correct enum descriptor. |
| var ed *descriptorV1.EnumDescriptorProto |
| e.FullName = pref.FullName(fd.GetPackage()) |
| if len(idxs) == 1 { |
| ed = fd.EnumType[idxs[0]] |
| e.FullName = e.FullName.Append(pref.Name(ed.GetName())) |
| } else { |
| md := fd.MessageType[idxs[0]] |
| e.FullName = e.FullName.Append(pref.Name(md.GetName())) |
| for _, i := range idxs[1 : len(idxs)-1] { |
| md = md.NestedType[i] |
| e.FullName = e.FullName.Append(pref.Name(md.GetName())) |
| } |
| ed = md.EnumType[idxs[len(idxs)-1]] |
| e.FullName = e.FullName.Append(pref.Name(ed.GetName())) |
| } |
| |
| // Derive the enum values. |
| for _, vd := range ed.GetValue() { |
| e.Values = append(e.Values, ptype.EnumValue{ |
| Name: pref.Name(vd.GetName()), |
| Number: pref.EnumNumber(vd.GetNumber()), |
| }) |
| } |
| } else { |
| // If the type does not implement legacyEnum, then there is no reliable |
| // way to derive the original protobuf type information. |
| // We are unable to use the global enum registry since it is |
| // unfortunately keyed by the full name, which we do not know. |
| // Furthermore, some generated enums register with a fork of |
| // golang/protobuf so the enum may not even be found in the registry. |
| // |
| // Instead, create a bogus enum descriptor to ensure that |
| // most operations continue to work. For example, textpb and jsonpb |
| // will be unable to parse a message with an enum value by name. |
| e.Syntax = pref.Proto2 |
| e.FullName = deriveFullName(t) |
| e.Values = []ptype.EnumValue{{Name: "INVALID", Number: math.MinInt32}} |
| } |
| |
| ed, err := ptype.NewEnum(e) |
| if err != nil { |
| panic(err) |
| } |
| enumDescCache.Store(t, ed) |
| return ed |
| } |