271 lines
7.6 KiB
Go
271 lines
7.6 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 proto
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import (
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"google.golang.org/protobuf/encoding/protowire"
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"google.golang.org/protobuf/internal/encoding/messageset"
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"google.golang.org/protobuf/internal/errors"
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"google.golang.org/protobuf/internal/flags"
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"google.golang.org/protobuf/internal/pragma"
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"google.golang.org/protobuf/reflect/protoreflect"
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"google.golang.org/protobuf/reflect/protoregistry"
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"google.golang.org/protobuf/runtime/protoiface"
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)
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// UnmarshalOptions configures the unmarshaler.
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//
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// Example usage:
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// err := UnmarshalOptions{DiscardUnknown: true}.Unmarshal(b, m)
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type UnmarshalOptions struct {
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pragma.NoUnkeyedLiterals
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// Merge merges the input into the destination message.
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// The default behavior is to always reset the message before unmarshaling,
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// unless Merge is specified.
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Merge bool
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// AllowPartial accepts input for messages that will result in missing
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// required fields. If AllowPartial is false (the default), Unmarshal will
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// return an error if there are any missing required fields.
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AllowPartial bool
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// If DiscardUnknown is set, unknown fields are ignored.
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DiscardUnknown bool
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// Resolver is used for looking up types when unmarshaling extension fields.
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// If nil, this defaults to using protoregistry.GlobalTypes.
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Resolver interface {
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FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)
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FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)
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}
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}
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// Unmarshal parses the wire-format message in b and places the result in m.
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func Unmarshal(b []byte, m Message) error {
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_, err := UnmarshalOptions{}.unmarshal(b, m.ProtoReflect())
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return err
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}
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// Unmarshal parses the wire-format message in b and places the result in m.
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func (o UnmarshalOptions) Unmarshal(b []byte, m Message) error {
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_, err := o.unmarshal(b, m.ProtoReflect())
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return err
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}
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// UnmarshalState parses a wire-format message and places the result in m.
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//
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// This method permits fine-grained control over the unmarshaler.
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// Most users should use Unmarshal instead.
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func (o UnmarshalOptions) UnmarshalState(in protoiface.UnmarshalInput) (protoiface.UnmarshalOutput, error) {
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return o.unmarshal(in.Buf, in.Message)
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}
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func (o UnmarshalOptions) unmarshal(b []byte, m protoreflect.Message) (out protoiface.UnmarshalOutput, err error) {
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if o.Resolver == nil {
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o.Resolver = protoregistry.GlobalTypes
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}
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if !o.Merge {
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Reset(m.Interface()) // TODO
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}
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allowPartial := o.AllowPartial
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o.Merge = true
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o.AllowPartial = true
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methods := protoMethods(m)
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if methods != nil && methods.Unmarshal != nil &&
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!(o.DiscardUnknown && methods.Flags&protoiface.SupportUnmarshalDiscardUnknown == 0) {
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in := protoiface.UnmarshalInput{
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Message: m,
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Buf: b,
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Resolver: o.Resolver,
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}
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if o.DiscardUnknown {
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in.Flags |= protoiface.UnmarshalDiscardUnknown
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}
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out, err = methods.Unmarshal(in)
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} else {
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err = o.unmarshalMessageSlow(b, m)
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}
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if err != nil {
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return out, err
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}
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if allowPartial || (out.Flags&protoiface.UnmarshalInitialized != 0) {
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return out, nil
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}
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return out, checkInitialized(m)
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}
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func (o UnmarshalOptions) unmarshalMessage(b []byte, m protoreflect.Message) error {
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_, err := o.unmarshal(b, m)
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return err
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}
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func (o UnmarshalOptions) unmarshalMessageSlow(b []byte, m protoreflect.Message) error {
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md := m.Descriptor()
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if messageset.IsMessageSet(md) {
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return unmarshalMessageSet(b, m, o)
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}
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fields := md.Fields()
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for len(b) > 0 {
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// Parse the tag (field number and wire type).
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num, wtyp, tagLen := protowire.ConsumeTag(b)
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if tagLen < 0 {
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return protowire.ParseError(tagLen)
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}
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if num > protowire.MaxValidNumber {
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return errors.New("invalid field number")
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}
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// Find the field descriptor for this field number.
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fd := fields.ByNumber(num)
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if fd == nil && md.ExtensionRanges().Has(num) {
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extType, err := o.Resolver.FindExtensionByNumber(md.FullName(), num)
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if err != nil && err != protoregistry.NotFound {
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return errors.New("%v: unable to resolve extension %v: %v", md.FullName(), num, err)
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}
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if extType != nil {
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fd = extType.TypeDescriptor()
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}
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}
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var err error
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if fd == nil {
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err = errUnknown
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} else if flags.ProtoLegacy {
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if fd.IsWeak() && fd.Message().IsPlaceholder() {
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err = errUnknown // weak referent is not linked in
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}
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}
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// Parse the field value.
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var valLen int
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switch {
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case err != nil:
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case fd.IsList():
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valLen, err = o.unmarshalList(b[tagLen:], wtyp, m.Mutable(fd).List(), fd)
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case fd.IsMap():
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valLen, err = o.unmarshalMap(b[tagLen:], wtyp, m.Mutable(fd).Map(), fd)
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default:
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valLen, err = o.unmarshalSingular(b[tagLen:], wtyp, m, fd)
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}
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if err != nil {
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if err != errUnknown {
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return err
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}
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valLen = protowire.ConsumeFieldValue(num, wtyp, b[tagLen:])
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if valLen < 0 {
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return protowire.ParseError(valLen)
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}
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if !o.DiscardUnknown {
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m.SetUnknown(append(m.GetUnknown(), b[:tagLen+valLen]...))
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}
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}
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b = b[tagLen+valLen:]
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}
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return nil
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}
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func (o UnmarshalOptions) unmarshalSingular(b []byte, wtyp protowire.Type, m protoreflect.Message, fd protoreflect.FieldDescriptor) (n int, err error) {
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v, n, err := o.unmarshalScalar(b, wtyp, fd)
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if err != nil {
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return 0, err
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}
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switch fd.Kind() {
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case protoreflect.GroupKind, protoreflect.MessageKind:
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m2 := m.Mutable(fd).Message()
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if err := o.unmarshalMessage(v.Bytes(), m2); err != nil {
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return n, err
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}
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default:
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// Non-message scalars replace the previous value.
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m.Set(fd, v)
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}
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return n, nil
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}
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func (o UnmarshalOptions) unmarshalMap(b []byte, wtyp protowire.Type, mapv protoreflect.Map, fd protoreflect.FieldDescriptor) (n int, err error) {
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if wtyp != protowire.BytesType {
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return 0, errUnknown
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}
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b, n = protowire.ConsumeBytes(b)
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if n < 0 {
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return 0, protowire.ParseError(n)
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}
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var (
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keyField = fd.MapKey()
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valField = fd.MapValue()
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key protoreflect.Value
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val protoreflect.Value
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haveKey bool
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haveVal bool
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)
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switch valField.Kind() {
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case protoreflect.GroupKind, protoreflect.MessageKind:
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val = mapv.NewValue()
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}
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// Map entries are represented as a two-element message with fields
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// containing the key and value.
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for len(b) > 0 {
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num, wtyp, n := protowire.ConsumeTag(b)
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if n < 0 {
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return 0, protowire.ParseError(n)
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}
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if num > protowire.MaxValidNumber {
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return 0, errors.New("invalid field number")
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}
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b = b[n:]
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err = errUnknown
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switch num {
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case 1:
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key, n, err = o.unmarshalScalar(b, wtyp, keyField)
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if err != nil {
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break
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}
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haveKey = true
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case 2:
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var v protoreflect.Value
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v, n, err = o.unmarshalScalar(b, wtyp, valField)
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if err != nil {
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break
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}
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switch valField.Kind() {
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case protoreflect.GroupKind, protoreflect.MessageKind:
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if err := o.unmarshalMessage(v.Bytes(), val.Message()); err != nil {
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return 0, err
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}
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default:
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val = v
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}
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haveVal = true
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}
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if err == errUnknown {
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n = protowire.ConsumeFieldValue(num, wtyp, b)
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if n < 0 {
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return 0, protowire.ParseError(n)
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}
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} else if err != nil {
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return 0, err
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}
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b = b[n:]
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}
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// Every map entry should have entries for key and value, but this is not strictly required.
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if !haveKey {
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key = keyField.Default()
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}
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if !haveVal {
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switch valField.Kind() {
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case protoreflect.GroupKind, protoreflect.MessageKind:
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default:
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val = valField.Default()
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}
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}
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mapv.Set(key.MapKey(), val)
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return n, nil
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}
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// errUnknown is used internally to indicate fields which should be added
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// to the unknown field set of a message. It is never returned from an exported
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// function.
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var errUnknown = errors.New("BUG: internal error (unknown)")
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