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// 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/flags"
"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
}
// 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 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
}
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
} else if flags.ProtoLegacy {
if fd.IsWeak() && fd.Message().IsPlaceholder() {
err = errUnknown // weak referent is not linked in
}
}
// 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")