176 lines
7.0 KiB
Go
176 lines
7.0 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package impl
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import (
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"reflect"
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"google.golang.org/protobuf/internal/descopts"
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"google.golang.org/protobuf/internal/encoding/messageset"
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ptag "google.golang.org/protobuf/internal/encoding/tag"
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"google.golang.org/protobuf/internal/filedesc"
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"google.golang.org/protobuf/internal/pragma"
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pref "google.golang.org/protobuf/reflect/protoreflect"
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preg "google.golang.org/protobuf/reflect/protoregistry"
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piface "google.golang.org/protobuf/runtime/protoiface"
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)
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func (xi *ExtensionInfo) initToLegacy() {
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xd := xi.desc
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var parent piface.MessageV1
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messageName := xd.ContainingMessage().FullName()
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if mt, _ := preg.GlobalTypes.FindMessageByName(messageName); mt != nil {
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// Create a new parent message and unwrap it if possible.
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mv := mt.New().Interface()
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t := reflect.TypeOf(mv)
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if mv, ok := mv.(unwrapper); ok {
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t = reflect.TypeOf(mv.protoUnwrap())
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}
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// Check whether the message implements the legacy v1 Message interface.
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mz := reflect.Zero(t).Interface()
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if mz, ok := mz.(piface.MessageV1); ok {
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parent = mz
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}
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}
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// Determine the v1 extension type, which is unfortunately not the same as
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// the v2 ExtensionType.GoType.
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extType := xi.goType
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switch extType.Kind() {
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case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
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extType = reflect.PtrTo(extType) // T -> *T for singular scalar fields
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}
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// Reconstruct the legacy enum full name.
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var enumName string
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if xd.Kind() == pref.EnumKind {
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enumName = legacyEnumName(xd.Enum())
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}
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// Derive the proto file that the extension was declared within.
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var filename string
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if fd := xd.ParentFile(); fd != nil {
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filename = fd.Path()
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}
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// For MessageSet extensions, the name used is the parent message.
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name := xd.FullName()
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if messageset.IsMessageSetExtension(xd) {
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name = name.Parent()
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}
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xi.ExtendedType = parent
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xi.ExtensionType = reflect.Zero(extType).Interface()
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xi.Field = int32(xd.Number())
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xi.Name = string(name)
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xi.Tag = ptag.Marshal(xd, enumName)
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xi.Filename = filename
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}
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// initFromLegacy initializes an ExtensionInfo from
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// the contents of the deprecated exported fields of the type.
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func (xi *ExtensionInfo) initFromLegacy() {
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// The v1 API returns "type incomplete" descriptors where only the
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// field number is specified. In such a case, use a placeholder.
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if xi.ExtendedType == nil || xi.ExtensionType == nil {
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xd := placeholderExtension{
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name: pref.FullName(xi.Name),
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number: pref.FieldNumber(xi.Field),
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}
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xi.desc = extensionTypeDescriptor{xd, xi}
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return
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}
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// Resolve enum or message dependencies.
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var ed pref.EnumDescriptor
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var md pref.MessageDescriptor
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t := reflect.TypeOf(xi.ExtensionType)
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isOptional := t.Kind() == reflect.Ptr && t.Elem().Kind() != reflect.Struct
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isRepeated := t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8
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if isOptional || isRepeated {
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t = t.Elem()
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}
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switch v := reflect.Zero(t).Interface().(type) {
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case pref.Enum:
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ed = v.Descriptor()
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case enumV1:
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ed = LegacyLoadEnumDesc(t)
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case pref.ProtoMessage:
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md = v.ProtoReflect().Descriptor()
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case messageV1:
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md = LegacyLoadMessageDesc(t)
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}
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// Derive basic field information from the struct tag.
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var evs pref.EnumValueDescriptors
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if ed != nil {
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evs = ed.Values()
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}
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fd := ptag.Unmarshal(xi.Tag, t, evs).(*filedesc.Field)
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// Construct a v2 ExtensionType.
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xd := &filedesc.Extension{L2: new(filedesc.ExtensionL2)}
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xd.L0.ParentFile = filedesc.SurrogateProto2
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xd.L0.FullName = pref.FullName(xi.Name)
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xd.L1.Number = pref.FieldNumber(xi.Field)
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xd.L1.Cardinality = fd.L1.Cardinality
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xd.L1.Kind = fd.L1.Kind
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xd.L2.IsPacked = fd.L1.IsPacked
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xd.L2.Default = fd.L1.Default
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xd.L1.Extendee = Export{}.MessageDescriptorOf(xi.ExtendedType)
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xd.L2.Enum = ed
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xd.L2.Message = md
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// Derive real extension field name for MessageSets.
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if messageset.IsMessageSet(xd.L1.Extendee) && md.FullName() == xd.L0.FullName {
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xd.L0.FullName = xd.L0.FullName.Append(messageset.ExtensionName)
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}
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tt := reflect.TypeOf(xi.ExtensionType)
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if isOptional {
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tt = tt.Elem()
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}
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xi.goType = tt
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xi.desc = extensionTypeDescriptor{xd, xi}
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}
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type placeholderExtension struct {
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name pref.FullName
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number pref.FieldNumber
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}
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func (x placeholderExtension) ParentFile() pref.FileDescriptor { return nil }
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func (x placeholderExtension) Parent() pref.Descriptor { return nil }
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func (x placeholderExtension) Index() int { return 0 }
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func (x placeholderExtension) Syntax() pref.Syntax { return 0 }
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func (x placeholderExtension) Name() pref.Name { return x.name.Name() }
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func (x placeholderExtension) FullName() pref.FullName { return x.name }
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func (x placeholderExtension) IsPlaceholder() bool { return true }
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func (x placeholderExtension) Options() pref.ProtoMessage { return descopts.Field }
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func (x placeholderExtension) Number() pref.FieldNumber { return x.number }
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func (x placeholderExtension) Cardinality() pref.Cardinality { return 0 }
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func (x placeholderExtension) Kind() pref.Kind { return 0 }
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func (x placeholderExtension) HasJSONName() bool { return false }
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func (x placeholderExtension) JSONName() string { return "" }
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func (x placeholderExtension) HasPresence() bool { return false }
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func (x placeholderExtension) HasOptionalKeyword() bool { return false }
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func (x placeholderExtension) IsExtension() bool { return true }
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func (x placeholderExtension) IsWeak() bool { return false }
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func (x placeholderExtension) IsPacked() bool { return false }
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func (x placeholderExtension) IsList() bool { return false }
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func (x placeholderExtension) IsMap() bool { return false }
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func (x placeholderExtension) MapKey() pref.FieldDescriptor { return nil }
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func (x placeholderExtension) MapValue() pref.FieldDescriptor { return nil }
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func (x placeholderExtension) HasDefault() bool { return false }
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func (x placeholderExtension) Default() pref.Value { return pref.Value{} }
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func (x placeholderExtension) DefaultEnumValue() pref.EnumValueDescriptor { return nil }
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func (x placeholderExtension) ContainingOneof() pref.OneofDescriptor { return nil }
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func (x placeholderExtension) ContainingMessage() pref.MessageDescriptor { return nil }
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func (x placeholderExtension) Enum() pref.EnumDescriptor { return nil }
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func (x placeholderExtension) Message() pref.MessageDescriptor { return nil }
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func (x placeholderExtension) ProtoType(pref.FieldDescriptor) { return }
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func (x placeholderExtension) ProtoInternal(pragma.DoNotImplement) { return }
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