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