proto/decode.go - protobuf.git - Git at Google

 // 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 proto

 import (
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/internal/encoding/messageset"
 	"google.golang.org/protobuf/internal/errors"
 	"google.golang.org/protobuf/internal/genid"
 	"google.golang.org/protobuf/internal/pragma"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
 	"google.golang.org/protobuf/runtime/protoiface"
 )

 // UnmarshalOptions configures the unmarshaler.
 //
 // Example usage:
 //
 //	err := UnmarshalOptions{DiscardUnknown: true}.Unmarshal(b, m)
 type UnmarshalOptions struct {
 	pragma.NoUnkeyedLiterals

 	// Merge merges the input into the destination message.
 	// The default behavior is to always reset the message before unmarshaling,
 	// unless Merge is specified.
 	Merge bool

 	// AllowPartial accepts input for messages that will result in missing
 	// required fields. If AllowPartial is false (the default), Unmarshal will
 	// return an error if there are any missing required fields.
 	AllowPartial bool

 	// If DiscardUnknown is set, unknown fields are ignored.
 	DiscardUnknown bool

 	// Resolver is used for looking up types when unmarshaling extension fields.
 	// If nil, this defaults to using protoregistry.GlobalTypes.
 	Resolver interface {
 		FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)
 		FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)
 	}

 	// RecursionLimit limits how deeply messages may be nested.
 	// If zero, a default limit is applied.
 	RecursionLimit int

 	//
 	// NoLazyDecoding turns off lazy decoding, which otherwise is enabled by
 	// default. Lazy decoding only affects submessages (annotated with [lazy =
 	// true] in the .proto file) within messages that use the Opaque API.
 	NoLazyDecoding bool
 }

 // Unmarshal parses the wire-format message in b and places the result in m.
 // The provided message must be mutable (e.g., a non-nil pointer to a message).
 //
 // See the [UnmarshalOptions] type if you need more control.
 func Unmarshal(b []byte, m Message) error {
 	_, err := UnmarshalOptions{RecursionLimit: protowire.DefaultRecursionLimit}.unmarshal(b, m.ProtoReflect())
 	return err
 }

 // Unmarshal parses the wire-format message in b and places the result in m.
 // The provided message must be mutable (e.g., a non-nil pointer to a message).
 func (o UnmarshalOptions) Unmarshal(b []byte, m Message) error {
 	if o.RecursionLimit == 0 {
 		o.RecursionLimit = protowire.DefaultRecursionLimit
 	}
 	_, err := o.unmarshal(b, m.ProtoReflect())
 	return err
 }

 // UnmarshalState parses a wire-format message and places the result in m.
 //
 // This method permits fine-grained control over the unmarshaler.
 // Most users should use [Unmarshal] instead.
 func (o UnmarshalOptions) UnmarshalState(in protoiface.UnmarshalInput) (protoiface.UnmarshalOutput, error) {
 	if o.RecursionLimit == 0 {
 		o.RecursionLimit = protowire.DefaultRecursionLimit
 	}
 	return o.unmarshal(in.Buf, in.Message)
 }

 // unmarshal is a centralized function that all unmarshal operations go through.
 // For profiling purposes, avoid changing the name of this function or
 // introducing other code paths for unmarshal that do not go through this.
 func (o UnmarshalOptions) unmarshal(b []byte, m protoreflect.Message) (out protoiface.UnmarshalOutput, err error) {
 	if o.Resolver == nil {
 		o.Resolver = protoregistry.GlobalTypes
 	}
 	if !o.Merge {
 		Reset(m.Interface())
 	}
 	allowPartial := o.AllowPartial
 	o.Merge = true
 	o.AllowPartial = true
 	methods := protoMethods(m)
 	if methods != nil && methods.Unmarshal != nil &&
 		!(o.DiscardUnknown && methods.Flags&protoiface.SupportUnmarshalDiscardUnknown == 0) {
 		in := protoiface.UnmarshalInput{
 			Message:  m,
 			Buf:      b,
 			Resolver: o.Resolver,
 			Depth:    o.RecursionLimit,
 		}
 		if o.DiscardUnknown {
 			in.Flags |= protoiface.UnmarshalDiscardUnknown
 		}

 		if !allowPartial {
 			// This does not affect how current unmarshal functions work, it just allows them
 			// to record this for lazy the decoding case.
 			in.Flags |= protoiface.UnmarshalCheckRequired
 		}
 		if o.NoLazyDecoding {
 			in.Flags |= protoiface.UnmarshalNoLazyDecoding
 		}

 		out, err = methods.Unmarshal(in)
 	} else {
 		o.RecursionLimit--
 		if o.RecursionLimit < 0 {
 			return out, errors.New("exceeded max recursion depth")
 		}
 		err = o.unmarshalMessageSlow(b, m)
 	}
 	if err != nil {
 		return out, err
 	}
 	if allowPartial || (out.Flags&protoiface.UnmarshalInitialized != 0) {
 		return out, nil
 	}
 	return out, checkInitialized(m)
 }

 func (o UnmarshalOptions) unmarshalMessage(b []byte, m protoreflect.Message) error {
 	_, err := o.unmarshal(b, m)
 	return err
 }

 func (o UnmarshalOptions) unmarshalMessageSlow(b []byte, m protoreflect.Message) error {
 	md := m.Descriptor()
 	if messageset.IsMessageSet(md) {
 		return o.unmarshalMessageSet(b, m)
 	}
 	fields := md.Fields()
 	for len(b) > 0 {
 		// Parse the tag (field number and wire type).
 		num, wtyp, tagLen := protowire.ConsumeTag(b)
 		if tagLen < 0 {
 			return errDecode
 		}
 		if num > protowire.MaxValidNumber {
 			return errDecode
 		}

 		// Find the field descriptor for this field number.
 		fd := fields.ByNumber(num)
 		if fd == nil && md.ExtensionRanges().Has(num) {
 			extType, err := o.Resolver.FindExtensionByNumber(md.FullName(), num)
 			if err != nil && err != protoregistry.NotFound {
 				return errors.New("%v: unable to resolve extension %v: %v", md.FullName(), num, err)
 			}
 			if extType != nil {
 				fd = extType.TypeDescriptor()
 			}
 		}
 		var err error
 		if fd == nil {
 			err = errUnknown
 		}

 		// Parse the field value.
 		var valLen int
 		switch {
 		case err != nil:
 		case fd.IsList():
 			valLen, err = o.unmarshalList(b[tagLen:], wtyp, m.Mutable(fd).List(), fd)
 		case fd.IsMap():
 			valLen, err = o.unmarshalMap(b[tagLen:], wtyp, m.Mutable(fd).Map(), fd)
 		default:
 			valLen, err = o.unmarshalSingular(b[tagLen:], wtyp, m, fd)
 		}
 		if err != nil {
 			if err != errUnknown {
 				return err
 			}
 			valLen = protowire.ConsumeFieldValue(num, wtyp, b[tagLen:])
 			if valLen < 0 {
 				return errDecode
 			}
 			if !o.DiscardUnknown {
 				m.SetUnknown(append(m.GetUnknown(), b[:tagLen+valLen]...))
 			}
 		}
 		b = b[tagLen+valLen:]
 	}
 	return nil
 }

 func (o UnmarshalOptions) unmarshalSingular(b []byte, wtyp protowire.Type, m protoreflect.Message, fd protoreflect.FieldDescriptor) (n int, err error) {
 	v, n, err := o.unmarshalScalar(b, wtyp, fd)
 	if err != nil {
 		return 0, err
 	}
 	switch fd.Kind() {
 	case protoreflect.GroupKind, protoreflect.MessageKind:
 		m2 := m.Mutable(fd).Message()
 		if err := o.unmarshalMessage(v.Bytes(), m2); err != nil {
 			return n, err
 		}
 	default:
 		// Non-message scalars replace the previous value.
 		m.Set(fd, v)
 	}
 	return n, nil
 }

 func (o UnmarshalOptions) unmarshalMap(b []byte, wtyp protowire.Type, mapv protoreflect.Map, fd protoreflect.FieldDescriptor) (n int, err error) {
 	if wtyp != protowire.BytesType {
 		return 0, errUnknown
 	}
 	b, n = protowire.ConsumeBytes(b)
 	if n < 0 {
 		return 0, errDecode
 	}
 	var (
 		keyField = fd.MapKey()
 		valField = fd.MapValue()
 		key      protoreflect.Value
 		val      protoreflect.Value
 		haveKey  bool
 		haveVal  bool
 	)
 	switch valField.Kind() {
 	case protoreflect.GroupKind, protoreflect.MessageKind:
 		val = mapv.NewValue()
 	}
 	// Map entries are represented as a two-element message with fields
 	// containing the key and value.
 	for len(b) > 0 {
 		num, wtyp, n := protowire.ConsumeTag(b)
 		if n < 0 {
 			return 0, errDecode
 		}
 		if num > protowire.MaxValidNumber {
 			return 0, errDecode
 		}
 		b = b[n:]
 		err = errUnknown
 		switch num {
 		case genid.MapEntry_Key_field_number:
 			key, n, err = o.unmarshalScalar(b, wtyp, keyField)
 			if err != nil {
 				break
 			}
 			haveKey = true
 		case genid.MapEntry_Value_field_number:
 			var v protoreflect.Value
 			v, n, err = o.unmarshalScalar(b, wtyp, valField)
 			if err != nil {
 				break
 			}
 			switch valField.Kind() {
 			case protoreflect.GroupKind, protoreflect.MessageKind:
 				if err := o.unmarshalMessage(v.Bytes(), val.Message()); err != nil {
 					return 0, err
 				}
 			default:
 				val = v
 			}
 			haveVal = true
 		}
 		if err == errUnknown {
 			n = protowire.ConsumeFieldValue(num, wtyp, b)
 			if n < 0 {
 				return 0, errDecode
 			}
 		} else if err != nil {
 			return 0, err
 		}
 		b = b[n:]
 	}
 	// Every map entry should have entries for key and value, but this is not strictly required.
 	if !haveKey {
 		key = keyField.Default()
 	}
 	if !haveVal {
 		switch valField.Kind() {
 		case protoreflect.GroupKind, protoreflect.MessageKind:
 		default:
 			val = valField.Default()
 		}
 	}
 	mapv.Set(key.MapKey(), val)
 	return n, nil
 }

 // errUnknown is used internally to indicate fields which should be added
 // to the unknown field set of a message. It is never returned from an exported
 // function.
 var errUnknown = errors.New("BUG: internal error (unknown)")

 var errDecode = errors.New("cannot parse invalid wire-format data")
	// 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 proto

	import (
	"google.golang.org/protobuf/encoding/protowire"
	"google.golang.org/protobuf/internal/encoding/messageset"
	"google.golang.org/protobuf/internal/errors"
	"google.golang.org/protobuf/internal/genid"
	"google.golang.org/protobuf/internal/pragma"
	"google.golang.org/protobuf/reflect/protoreflect"
	"google.golang.org/protobuf/reflect/protoregistry"
	"google.golang.org/protobuf/runtime/protoiface"
	)

	// UnmarshalOptions configures the unmarshaler.
	//
	// Example usage:
	//
	// err := UnmarshalOptions{DiscardUnknown: true}.Unmarshal(b, m)
	type UnmarshalOptions struct {
	pragma.NoUnkeyedLiterals

	// Merge merges the input into the destination message.
	// The default behavior is to always reset the message before unmarshaling,
	// unless Merge is specified.
	Merge bool

	// AllowPartial accepts input for messages that will result in missing
	// required fields. If AllowPartial is false (the default), Unmarshal will
	// return an error if there are any missing required fields.
	AllowPartial bool

	// If DiscardUnknown is set, unknown fields are ignored.
	DiscardUnknown bool

	// Resolver is used for looking up types when unmarshaling extension fields.
	// If nil, this defaults to using protoregistry.GlobalTypes.
	Resolver interface {
	FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)
	FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)
	}

	// RecursionLimit limits how deeply messages may be nested.
	// If zero, a default limit is applied.
	RecursionLimit int

	//
	// NoLazyDecoding turns off lazy decoding, which otherwise is enabled by
	// default. Lazy decoding only affects submessages (annotated with [lazy =
	// true] in the .proto file) within messages that use the Opaque API.
	NoLazyDecoding bool
	}

	// Unmarshal parses the wire-format message in b and places the result in m.
	// The provided message must be mutable (e.g., a non-nil pointer to a message).
	//
	// See the [UnmarshalOptions] type if you need more control.
	func Unmarshal(b []byte, m Message) error {
	_, err := UnmarshalOptions{RecursionLimit: protowire.DefaultRecursionLimit}.unmarshal(b, m.ProtoReflect())
	return err
	}

	// Unmarshal parses the wire-format message in b and places the result in m.
	// The provided message must be mutable (e.g., a non-nil pointer to a message).
	func (o UnmarshalOptions) Unmarshal(b []byte, m Message) error {
	if o.RecursionLimit == 0 {
	o.RecursionLimit = protowire.DefaultRecursionLimit
	}
	_, err := o.unmarshal(b, m.ProtoReflect())
	return err
	}

	// UnmarshalState parses a wire-format message and places the result in m.
	//
	// This method permits fine-grained control over the unmarshaler.
	// Most users should use [Unmarshal] instead.
	func (o UnmarshalOptions) UnmarshalState(in protoiface.UnmarshalInput) (protoiface.UnmarshalOutput, error) {
	if o.RecursionLimit == 0 {
	o.RecursionLimit = protowire.DefaultRecursionLimit
	}
	return o.unmarshal(in.Buf, in.Message)
	}

	// unmarshal is a centralized function that all unmarshal operations go through.
	// For profiling purposes, avoid changing the name of this function or
	// introducing other code paths for unmarshal that do not go through this.
	func (o UnmarshalOptions) unmarshal(b []byte, m protoreflect.Message) (out protoiface.UnmarshalOutput, err error) {
	if o.Resolver == nil {
	o.Resolver = protoregistry.GlobalTypes
	}
	if !o.Merge {
	Reset(m.Interface())
	}
	allowPartial := o.AllowPartial
	o.Merge = true
	o.AllowPartial = true
	methods := protoMethods(m)
	if methods != nil && methods.Unmarshal != nil &&
	!(o.DiscardUnknown && methods.Flags&protoiface.SupportUnmarshalDiscardUnknown == 0) {
	in := protoiface.UnmarshalInput{
	Message: m,
	Buf: b,
	Resolver: o.Resolver,
	Depth: o.RecursionLimit,
	}
	if o.DiscardUnknown {
	in.Flags \|= protoiface.UnmarshalDiscardUnknown
	}

	if !allowPartial {
	// This does not affect how current unmarshal functions work, it just allows them
	// to record this for lazy the decoding case.
	in.Flags \|= protoiface.UnmarshalCheckRequired
	}
	if o.NoLazyDecoding {
	in.Flags \|= protoiface.UnmarshalNoLazyDecoding
	}

	out, err = methods.Unmarshal(in)
	} else {
	o.RecursionLimit--
	if o.RecursionLimit < 0 {
	return out, errors.New("exceeded max recursion depth")
	}
	err = o.unmarshalMessageSlow(b, m)
	}
	if err != nil {
	return out, err
	}
	if allowPartial \|\| (out.Flags&protoiface.UnmarshalInitialized != 0) {
	return out, nil
	}
	return out, checkInitialized(m)
	}

	func (o UnmarshalOptions) unmarshalMessage(b []byte, m protoreflect.Message) error {
	_, err := o.unmarshal(b, m)
	return err
	}

	func (o UnmarshalOptions) unmarshalMessageSlow(b []byte, m protoreflect.Message) error {
	md := m.Descriptor()
	if messageset.IsMessageSet(md) {
	return o.unmarshalMessageSet(b, m)
	}
	fields := md.Fields()
	for len(b) > 0 {
	// Parse the tag (field number and wire type).
	num, wtyp, tagLen := protowire.ConsumeTag(b)
	if tagLen < 0 {
	return errDecode
	}
	if num > protowire.MaxValidNumber {
	return errDecode
	}

	// Find the field descriptor for this field number.
	fd := fields.ByNumber(num)
	if fd == nil && md.ExtensionRanges().Has(num) {
	extType, err := o.Resolver.FindExtensionByNumber(md.FullName(), num)
	if err != nil && err != protoregistry.NotFound {
	return errors.New("%v: unable to resolve extension %v: %v", md.FullName(), num, err)
	}
	if extType != nil {
	fd = extType.TypeDescriptor()
	}
	}
	var err error
	if fd == nil {
	err = errUnknown
	}

	// Parse the field value.
	var valLen int
	switch {
	case err != nil:
	case fd.IsList():
	valLen, err = o.unmarshalList(b[tagLen:], wtyp, m.Mutable(fd).List(), fd)
	case fd.IsMap():
	valLen, err = o.unmarshalMap(b[tagLen:], wtyp, m.Mutable(fd).Map(), fd)
	default:
	valLen, err = o.unmarshalSingular(b[tagLen:], wtyp, m, fd)
	}
	if err != nil {
	if err != errUnknown {
	return err
	}
	valLen = protowire.ConsumeFieldValue(num, wtyp, b[tagLen:])
	if valLen < 0 {
	return errDecode
	}
	if !o.DiscardUnknown {
	m.SetUnknown(append(m.GetUnknown(), b[:tagLen+valLen]...))
	}
	}
	b = b[tagLen+valLen:]
	}
	return nil
	}

	func (o UnmarshalOptions) unmarshalSingular(b []byte, wtyp protowire.Type, m protoreflect.Message, fd protoreflect.FieldDescriptor) (n int, err error) {
	v, n, err := o.unmarshalScalar(b, wtyp, fd)
	if err != nil {
	return 0, err
	}
	switch fd.Kind() {
	case protoreflect.GroupKind, protoreflect.MessageKind:
	m2 := m.Mutable(fd).Message()
	if err := o.unmarshalMessage(v.Bytes(), m2); err != nil {
	return n, err
	}
	default:
	// Non-message scalars replace the previous value.
	m.Set(fd, v)
	}
	return n, nil
	}

	func (o UnmarshalOptions) unmarshalMap(b []byte, wtyp protowire.Type, mapv protoreflect.Map, fd protoreflect.FieldDescriptor) (n int, err error) {
	if wtyp != protowire.BytesType {
	return 0, errUnknown
	}
	b, n = protowire.ConsumeBytes(b)
	if n < 0 {
	return 0, errDecode
	}
	var (
	keyField = fd.MapKey()
	valField = fd.MapValue()
	key protoreflect.Value
	val protoreflect.Value
	haveKey bool
	haveVal bool
	)
	switch valField.Kind() {
	case protoreflect.GroupKind, protoreflect.MessageKind:
	val = mapv.NewValue()
	}
	// Map entries are represented as a two-element message with fields
	// containing the key and value.
	for len(b) > 0 {
	num, wtyp, n := protowire.ConsumeTag(b)
	if n < 0 {
	return 0, errDecode
	}
	if num > protowire.MaxValidNumber {
	return 0, errDecode
	}
	b = b[n:]
	err = errUnknown
	switch num {
	case genid.MapEntry_Key_field_number:
	key, n, err = o.unmarshalScalar(b, wtyp, keyField)
	if err != nil {
	break
	}
	haveKey = true
	case genid.MapEntry_Value_field_number:
	var v protoreflect.Value
	v, n, err = o.unmarshalScalar(b, wtyp, valField)
	if err != nil {
	break
	}
	switch valField.Kind() {
	case protoreflect.GroupKind, protoreflect.MessageKind:
	if err := o.unmarshalMessage(v.Bytes(), val.Message()); err != nil {
	return 0, err
	}
	default:
	val = v
	}
	haveVal = true
	}
	if err == errUnknown {
	n = protowire.ConsumeFieldValue(num, wtyp, b)
	if n < 0 {
	return 0, errDecode
	}
	} else if err != nil {
	return 0, err
	}
	b = b[n:]
	}
	// Every map entry should have entries for key and value, but this is not strictly required.
	if !haveKey {
	key = keyField.Default()
	}
	if !haveVal {
	switch valField.Kind() {
	case protoreflect.GroupKind, protoreflect.MessageKind:
	default:
	val = valField.Default()
	}
	}
	mapv.Set(key.MapKey(), val)
	return n, nil
	}

	// errUnknown is used internally to indicate fields which should be added
	// to the unknown field set of a message. It is never returned from an exported
	// function.
	var errUnknown = errors.New("BUG: internal error (unknown)")

	var errDecode = errors.New("cannot parse invalid wire-format data")