| // 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" |
| "sync" |
| |
| pvalue "google.golang.org/protobuf/internal/value" |
| "google.golang.org/protobuf/reflect/protoreflect" |
| pref "google.golang.org/protobuf/reflect/protoreflect" |
| "google.golang.org/protobuf/reflect/prototype" |
| ) |
| |
| // legacyWrapEnum wraps v as a protoreflect.Enum, |
| // where v must be a int32 kind and not implement the v2 API already. |
| func legacyWrapEnum(v reflect.Value) pref.Enum { |
| et := legacyLoadEnumType(v.Type()) |
| return et.New(pref.EnumNumber(v.Int())) |
| } |
| |
| var legacyEnumTypeCache sync.Map // map[reflect.Type]protoreflect.EnumType |
| |
| // legacyLoadEnumType dynamically loads a protoreflect.EnumType for t, |
| // where t must be an int32 kind and not implement the v2 API already. |
| func legacyLoadEnumType(t reflect.Type) pref.EnumType { |
| // Fast-path: check if a EnumType is cached for this concrete type. |
| if et, ok := legacyEnumTypeCache.Load(t); ok { |
| return et.(pref.EnumType) |
| } |
| |
| // Slow-path: derive enum descriptor and initialize EnumType. |
| var et pref.EnumType |
| var m sync.Map // map[protoreflect.EnumNumber]proto.Enum |
| ed := LegacyLoadEnumDesc(t) |
| et = &prototype.Enum{ |
| EnumDescriptor: ed, |
| NewEnum: func(n pref.EnumNumber) pref.Enum { |
| if e, ok := m.Load(n); ok { |
| return e.(pref.Enum) |
| } |
| e := &legacyEnumWrapper{num: n, pbTyp: et, goTyp: t} |
| m.Store(n, e) |
| return e |
| }, |
| } |
| if et, ok := legacyEnumTypeCache.LoadOrStore(t, et); ok { |
| return et.(pref.EnumType) |
| } |
| return et |
| } |
| |
| type legacyEnumWrapper struct { |
| num pref.EnumNumber |
| pbTyp pref.EnumType |
| goTyp reflect.Type |
| } |
| |
| func (e *legacyEnumWrapper) Descriptor() pref.EnumDescriptor { |
| return e.pbTyp.Descriptor() |
| } |
| func (e *legacyEnumWrapper) Number() pref.EnumNumber { |
| return e.num |
| } |
| func (e *legacyEnumWrapper) ProtoReflect() pref.Enum { |
| return e |
| } |
| func (e *legacyEnumWrapper) ProtoUnwrap() interface{} { |
| v := reflect.New(e.goTyp).Elem() |
| v.SetInt(int64(e.num)) |
| return v.Interface() |
| } |
| |
| var ( |
| _ pref.Enum = (*legacyEnumWrapper)(nil) |
| _ pvalue.Unwrapper = (*legacyEnumWrapper)(nil) |
| ) |
| |
| var legacyEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor |
| |
| var legacyEnumNumberType = reflect.TypeOf(pref.EnumNumber(0)) |
| |
| // LegacyLoadEnumDesc returns an EnumDescriptor derived from the Go type, |
| // which must be an int32 kind and not implement the v2 API already. |
| // |
| // This is exported for testing purposes. |
| func LegacyLoadEnumDesc(t reflect.Type) pref.EnumDescriptor { |
| // Fast-path: check if an EnumDescriptor is cached for this concrete type. |
| if ed, ok := legacyEnumDescCache.Load(t); ok { |
| return ed.(pref.EnumDescriptor) |
| } |
| |
| // Slow-path: initialize EnumDescriptor from the raw descriptor. |
| ev := reflect.Zero(t).Interface() |
| if _, ok := ev.(pref.Enum); ok { |
| panic(fmt.Sprintf("%v already implements proto.Enum", t)) |
| } |
| edV1, ok := ev.(enumV1) |
| if !ok { |
| panic(fmt.Sprintf("enum %v is no longer supported; please regenerate", t)) |
| } |
| b, idxs := edV1.EnumDescriptor() |
| |
| var ed pref.EnumDescriptor |
| if len(idxs) == 1 { |
| ed = legacyLoadFileDesc(b).Enums().Get(idxs[0]) |
| } else { |
| md := legacyLoadFileDesc(b).Messages().Get(idxs[0]) |
| for _, i := range idxs[1 : len(idxs)-1] { |
| md = md.Messages().Get(i) |
| } |
| ed = md.Enums().Get(idxs[len(idxs)-1]) |
| } |
| if ed, ok := legacyEnumDescCache.LoadOrStore(t, ed); ok { |
| return ed.(protoreflect.EnumDescriptor) |
| } |
| return ed |
| } |