1// Copyright 2018 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package impl 6 7import ( 8 "fmt" 9 "reflect" 10 "strings" 11 "sync" 12 13 "google.golang.org/protobuf/internal/filedesc" 14 "google.golang.org/protobuf/internal/strs" 15 "google.golang.org/protobuf/reflect/protoreflect" 16 pref "google.golang.org/protobuf/reflect/protoreflect" 17) 18 19// legacyEnumName returns the name of enums used in legacy code. 20// It is neither the protobuf full name nor the qualified Go name, 21// but rather an odd hybrid of both. 22func legacyEnumName(ed pref.EnumDescriptor) string { 23 var protoPkg string 24 enumName := string(ed.FullName()) 25 if fd := ed.ParentFile(); fd != nil { 26 protoPkg = string(fd.Package()) 27 enumName = strings.TrimPrefix(enumName, protoPkg+".") 28 } 29 if protoPkg == "" { 30 return strs.GoCamelCase(enumName) 31 } 32 return protoPkg + "." + strs.GoCamelCase(enumName) 33} 34 35// legacyWrapEnum wraps v as a protoreflect.Enum, 36// where v must be a int32 kind and not implement the v2 API already. 37func legacyWrapEnum(v reflect.Value) pref.Enum { 38 et := legacyLoadEnumType(v.Type()) 39 return et.New(pref.EnumNumber(v.Int())) 40} 41 42var legacyEnumTypeCache sync.Map // map[reflect.Type]protoreflect.EnumType 43 44// legacyLoadEnumType dynamically loads a protoreflect.EnumType for t, 45// where t must be an int32 kind and not implement the v2 API already. 46func legacyLoadEnumType(t reflect.Type) pref.EnumType { 47 // Fast-path: check if a EnumType is cached for this concrete type. 48 if et, ok := legacyEnumTypeCache.Load(t); ok { 49 return et.(pref.EnumType) 50 } 51 52 // Slow-path: derive enum descriptor and initialize EnumType. 53 var et pref.EnumType 54 ed := LegacyLoadEnumDesc(t) 55 et = &legacyEnumType{ 56 desc: ed, 57 goType: t, 58 } 59 if et, ok := legacyEnumTypeCache.LoadOrStore(t, et); ok { 60 return et.(pref.EnumType) 61 } 62 return et 63} 64 65type legacyEnumType struct { 66 desc pref.EnumDescriptor 67 goType reflect.Type 68 m sync.Map // map[protoreflect.EnumNumber]proto.Enum 69} 70 71func (t *legacyEnumType) New(n pref.EnumNumber) pref.Enum { 72 if e, ok := t.m.Load(n); ok { 73 return e.(pref.Enum) 74 } 75 e := &legacyEnumWrapper{num: n, pbTyp: t, goTyp: t.goType} 76 t.m.Store(n, e) 77 return e 78} 79func (t *legacyEnumType) Descriptor() pref.EnumDescriptor { 80 return t.desc 81} 82 83type legacyEnumWrapper struct { 84 num pref.EnumNumber 85 pbTyp pref.EnumType 86 goTyp reflect.Type 87} 88 89func (e *legacyEnumWrapper) Descriptor() pref.EnumDescriptor { 90 return e.pbTyp.Descriptor() 91} 92func (e *legacyEnumWrapper) Type() pref.EnumType { 93 return e.pbTyp 94} 95func (e *legacyEnumWrapper) Number() pref.EnumNumber { 96 return e.num 97} 98func (e *legacyEnumWrapper) ProtoReflect() pref.Enum { 99 return e 100} 101func (e *legacyEnumWrapper) protoUnwrap() interface{} { 102 v := reflect.New(e.goTyp).Elem() 103 v.SetInt(int64(e.num)) 104 return v.Interface() 105} 106 107var ( 108 _ pref.Enum = (*legacyEnumWrapper)(nil) 109 _ unwrapper = (*legacyEnumWrapper)(nil) 110) 111 112var legacyEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor 113 114// LegacyLoadEnumDesc returns an EnumDescriptor derived from the Go type, 115// which must be an int32 kind and not implement the v2 API already. 116// 117// This is exported for testing purposes. 118func LegacyLoadEnumDesc(t reflect.Type) pref.EnumDescriptor { 119 // Fast-path: check if an EnumDescriptor is cached for this concrete type. 120 if ed, ok := legacyEnumDescCache.Load(t); ok { 121 return ed.(pref.EnumDescriptor) 122 } 123 124 // Slow-path: initialize EnumDescriptor from the raw descriptor. 125 ev := reflect.Zero(t).Interface() 126 if _, ok := ev.(pref.Enum); ok { 127 panic(fmt.Sprintf("%v already implements proto.Enum", t)) 128 } 129 edV1, ok := ev.(enumV1) 130 if !ok { 131 return aberrantLoadEnumDesc(t) 132 } 133 b, idxs := edV1.EnumDescriptor() 134 135 var ed pref.EnumDescriptor 136 if len(idxs) == 1 { 137 ed = legacyLoadFileDesc(b).Enums().Get(idxs[0]) 138 } else { 139 md := legacyLoadFileDesc(b).Messages().Get(idxs[0]) 140 for _, i := range idxs[1 : len(idxs)-1] { 141 md = md.Messages().Get(i) 142 } 143 ed = md.Enums().Get(idxs[len(idxs)-1]) 144 } 145 if ed, ok := legacyEnumDescCache.LoadOrStore(t, ed); ok { 146 return ed.(protoreflect.EnumDescriptor) 147 } 148 return ed 149} 150 151var aberrantEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor 152 153// aberrantLoadEnumDesc returns an EnumDescriptor derived from the Go type, 154// which must not implement protoreflect.Enum or enumV1. 155// 156// If the type does not implement enumV1, then there is no reliable 157// way to derive the original protobuf type information. 158// We are unable to use the global enum registry since it is 159// unfortunately keyed by the protobuf full name, which we also do not know. 160// Thus, this produces some bogus enum descriptor based on the Go type name. 161func aberrantLoadEnumDesc(t reflect.Type) pref.EnumDescriptor { 162 // Fast-path: check if an EnumDescriptor is cached for this concrete type. 163 if ed, ok := aberrantEnumDescCache.Load(t); ok { 164 return ed.(pref.EnumDescriptor) 165 } 166 167 // Slow-path: construct a bogus, but unique EnumDescriptor. 168 ed := &filedesc.Enum{L2: new(filedesc.EnumL2)} 169 ed.L0.FullName = AberrantDeriveFullName(t) // e.g., github_com.user.repo.MyEnum 170 ed.L0.ParentFile = filedesc.SurrogateProto3 171 ed.L2.Values.List = append(ed.L2.Values.List, filedesc.EnumValue{}) 172 173 // TODO: Use the presence of a UnmarshalJSON method to determine proto2? 174 175 vd := &ed.L2.Values.List[0] 176 vd.L0.FullName = ed.L0.FullName + "_UNKNOWN" // e.g., github_com.user.repo.MyEnum_UNKNOWN 177 vd.L0.ParentFile = ed.L0.ParentFile 178 vd.L0.Parent = ed 179 180 // TODO: We could use the String method to obtain some enum value names by 181 // starting at 0 and print the enum until it produces invalid identifiers. 182 // An exhaustive query is clearly impractical, but can be best-effort. 183 184 if ed, ok := aberrantEnumDescCache.LoadOrStore(t, ed); ok { 185 return ed.(pref.EnumDescriptor) 186 } 187 return ed 188} 189 190// AberrantDeriveFullName derives a fully qualified protobuf name for the given Go type 191// The provided name is not guaranteed to be stable nor universally unique. 192// It should be sufficiently unique within a program. 193// 194// This is exported for testing purposes. 195func AberrantDeriveFullName(t reflect.Type) pref.FullName { 196 sanitize := func(r rune) rune { 197 switch { 198 case r == '/': 199 return '.' 200 case 'a' <= r && r <= 'z', 'A' <= r && r <= 'Z', '0' <= r && r <= '9': 201 return r 202 default: 203 return '_' 204 } 205 } 206 prefix := strings.Map(sanitize, t.PkgPath()) 207 suffix := strings.Map(sanitize, t.Name()) 208 if suffix == "" { 209 suffix = fmt.Sprintf("UnknownX%X", reflect.ValueOf(t).Pointer()) 210 } 211 212 ss := append(strings.Split(prefix, "."), suffix) 213 for i, s := range ss { 214 if s == "" || ('0' <= s[0] && s[0] <= '9') { 215 ss[i] = "x" + s 216 } 217 } 218 return pref.FullName(strings.Join(ss, ".")) 219} 220