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// Copyright 2010 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 (
"errors"
"fmt"
"reflect"
"google.golang.org/protobuf/encoding/protowire"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/reflect/protoregistry"
"google.golang.org/protobuf/runtime/protoiface"
"google.golang.org/protobuf/runtime/protoimpl"
)
type (
// ExtensionDesc represents an extension descriptor and
// is used to interact with an extension field in a message.
//
// Variables of this type are generated in code by protoc-gen-go.
ExtensionDesc = protoimpl.ExtensionInfo
// ExtensionRange represents a range of message extensions.
// Used in code generated by protoc-gen-go.
ExtensionRange = protoiface.ExtensionRangeV1
// Deprecated: Do not use; this is an internal type.
Extension = protoimpl.ExtensionFieldV1
// Deprecated: Do not use; this is an internal type.
XXX_InternalExtensions = protoimpl.ExtensionFields
)
// ErrMissingExtension reports whether the extension was not present.
var ErrMissingExtension = errors.New("proto: missing extension")
var errNotExtendable = errors.New("proto: not an extendable proto.Message")
// HasExtension reports whether the extension field is present in m
// either as an explicitly populated field or as an unknown field.
func HasExtension(m Message, xt *ExtensionDesc) (has bool) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() {
return false
}
// Check whether any populated known field matches the field number.
xtd := xt.TypeDescriptor()
if isValidExtension(mr.Descriptor(), xtd) {
has = mr.Has(xtd)
} else {
mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
has = int32(fd.Number()) == xt.Field
return !has
})
}
// Check whether any unknown field matches the field number.
for b := mr.GetUnknown(); !has && len(b) > 0; {
num, _, n := protowire.ConsumeField(b)
has = int32(num) == xt.Field
b = b[n:]
}
return has
}
// ClearExtension removes the extension field from m
// either as an explicitly populated field or as an unknown field.
func ClearExtension(m Message, xt *ExtensionDesc) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() {
return
}
xtd := xt.TypeDescriptor()
if isValidExtension(mr.Descriptor(), xtd) {
mr.Clear(xtd)
} else {
mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
if int32(fd.Number()) == xt.Field {
mr.Clear(fd)
return false
}
return true
})
}
clearUnknown(mr, fieldNum(xt.Field))
}
// ClearAllExtensions clears all extensions from m.
// This includes populated fields and unknown fields in the extension range.
func ClearAllExtensions(m Message) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() {
return
}
mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
if fd.IsExtension() {
mr.Clear(fd)
}
return true
})
clearUnknown(mr, mr.Descriptor().ExtensionRanges())
}
// GetExtension retrieves a proto2 extended field from m.
//
// If the descriptor is type complete (i.e., ExtensionDesc.ExtensionType is non-nil),
// then GetExtension parses the encoded field and returns a Go value of the specified type.
// If the field is not present, then the default value is returned (if one is specified),
// otherwise ErrMissingExtension is reported.
//
// If the descriptor is type incomplete (i.e., ExtensionDesc.ExtensionType is nil),
// then GetExtension returns the raw encoded bytes for the extension field.
func GetExtension(m Message, xt *ExtensionDesc) (interface{}, error) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
return nil, errNotExtendable
}
// Retrieve the unknown fields for this extension field.
var bo protoreflect.RawFields
for bi := mr.GetUnknown(); len(bi) > 0; {
num, _, n := protowire.ConsumeField(bi)
if int32(num) == xt.Field {
bo = append(bo, bi[:n]...)
}
bi = bi[n:]
}
// For type incomplete descriptors, only retrieve the unknown fields.
if xt.ExtensionType == nil {
return []byte(bo), nil
}
// If the extension field only exists as unknown fields, unmarshal it.
// This is rarely done since proto.Unmarshal eagerly unmarshals extensions.
xtd := xt.TypeDescriptor()
if !isValidExtension(mr.Descriptor(), xtd) {
return nil, fmt.Errorf("proto: bad extended type; %T does not extend %T", xt.ExtendedType, m)
}
if !mr.Has(xtd) && len(bo) > 0 {
m2 := mr.New()
if err := (proto.UnmarshalOptions{
Resolver: extensionResolver{xt},
}.Unmarshal(bo, m2.Interface())); err != nil {
return nil, err
}
if m2.Has(xtd) {
mr.Set(xtd, m2.Get(xtd))
clearUnknown(mr, fieldNum(xt.Field))
}
}
// Check whether the message has the extension field set or a default.
var pv protoreflect.Value
switch {
case mr.Has(xtd):
pv = mr.Get(xtd)
case xtd.HasDefault():
pv = xtd.Default()
default:
return nil, ErrMissingExtension
}
v := xt.InterfaceOf(pv)
rv := reflect.ValueOf(v)
if isScalarKind(rv.Kind()) {
rv2 := reflect.New(rv.Type())
rv2.Elem().Set(rv)
v = rv2.Interface()
}
return v, nil
}
// extensionResolver is a custom extension resolver that stores a single
// extension type that takes precedence over the global registry.
type extensionResolver struct{ xt protoreflect.ExtensionType }
func (r extensionResolver) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
if xtd := r.xt.TypeDescriptor(); xtd.FullName() == field {
return r.xt, nil
}
return protoregistry.GlobalTypes.FindExtensionByName(field)
}
func (r extensionResolver) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
if xtd := r.xt.TypeDescriptor(); xtd.ContainingMessage().FullName() == message && xtd.Number() == field {
return r.xt, nil
}
return protoregistry.GlobalTypes.FindExtensionByNumber(message, field)
}
// GetExtensions returns a list of the extensions values present in m,
// corresponding with the provided list of extension descriptors, xts.
// If an extension is missing in m, the corresponding value is nil.
func GetExtensions(m Message, xts []*ExtensionDesc) ([]interface{}, error) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() {
return nil, errNotExtendable
}
vs := make([]interface{}, len(xts))
for i, xt := range xts {
v, err := GetExtension(m, xt)
if err != nil {
if err == ErrMissingExtension {
continue
}
return vs, err
}
vs[i] = v
}
return vs, nil
}
// SetExtension sets an extension field in m to the provided value.
func SetExtension(m Message, xt *ExtensionDesc, v interface{}) error {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
return errNotExtendable
}
rv := reflect.ValueOf(v)
if reflect.TypeOf(v) != reflect.TypeOf(xt.ExtensionType) {
return fmt.Errorf("proto: bad extension value type. got: %T, want: %T", v, xt.ExtensionType)
}
if rv.Kind() == reflect.Ptr {
if rv.IsNil() {
return fmt.Errorf("proto: SetExtension called with nil value of type %T", v)
}
if isScalarKind(rv.Elem().Kind()) {
v = rv.Elem().Interface()
}
}
xtd := xt.TypeDescriptor()
if !isValidExtension(mr.Descriptor(), xtd) {
return fmt.Errorf("proto: bad extended type; %T does not extend %T", xt.ExtendedType, m)
}
mr.Set(xtd, xt.ValueOf(v))
clearUnknown(mr, fieldNum(xt.Field))
return nil
}
// SetRawExtension inserts b into the unknown fields of m.
//
// Deprecated: Use Message.ProtoReflect.SetUnknown instead.
func SetRawExtension(m Message, fnum int32, b []byte) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() {
return
}
// Verify that the raw field is valid.
for b0 := b; len(b0) > 0; {
num, _, n := protowire.ConsumeField(b0)
if int32(num) != fnum {
panic(fmt.Sprintf("mismatching field number: got %d, want %d", num, fnum))
}
b0 = b0[n:]
}
ClearExtension(m, &ExtensionDesc{Field: fnum})
mr.SetUnknown(append(mr.GetUnknown(), b...))
}
// ExtensionDescs returns a list of extension descriptors found in m,
// containing descriptors for both populated extension fields in m and
// also unknown fields of m that are in the extension range.
// For the later case, an type incomplete descriptor is provided where only
// the ExtensionDesc.Field field is populated.
// The order of the extension descriptors is undefined.
func ExtensionDescs(m Message) ([]*ExtensionDesc, error) {
mr := MessageReflect(m)
if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
return nil, errNotExtendable
}
// Collect a set of known extension descriptors.
extDescs := make(map[protoreflect.FieldNumber]*ExtensionDesc)
mr.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
if fd.IsExtension() {
xt := fd.(protoreflect.ExtensionTypeDescriptor)
if xd, ok := xt.Type().(*ExtensionDesc); ok {
extDescs[fd.Number()] = xd
}
}
return true
})
// Collect a set of unknown extension descriptors.
extRanges := mr.Descriptor().ExtensionRanges()
for b := mr.GetUnknown(); len(b) > 0; {
num, _, n := protowire.ConsumeField(b)
if extRanges.Has(num) && extDescs[num] == nil {
extDescs[num] = nil
}
b = b[n:]
}
// Transpose the set of descriptors into a list.
var xts []*ExtensionDesc
for num, xt := range extDescs {
if xt == nil {
xt = &ExtensionDesc{Field: int32(num)}
}
xts = append(xts, xt)
}
return xts, nil
}
// isValidExtension reports whether xtd is a valid extension descriptor for md.
func isValidExtension(md protoreflect.MessageDescriptor, xtd protoreflect.ExtensionTypeDescriptor) bool {
return xtd.ContainingMessage() == md && md.ExtensionRanges().Has(xtd.Number())
}
// isScalarKind reports whether k is a protobuf scalar kind (except bytes).
// This function exists for historical reasons since the representation of
// scalars differs between v1 and v2, where v1 uses *T and v2 uses T.
func isScalarKind(k reflect.Kind) bool {
switch k {
case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
return true
default:
return false
}
}
// clearUnknown removes unknown fields from m where remover.Has reports true.
func clearUnknown(m protoreflect.Message, remover interface {
Has(protoreflect.FieldNumber) bool
}) {
var bo protoreflect.RawFields
for bi := m.GetUnknown(); len(bi) > 0; {
num, _, n := protowire.ConsumeField(bi)
if !remover.Has(num) {
bo = append(bo, bi[:n]...)
}
bi = bi[n:]
}
if bi := m.GetUnknown(); len(bi) != len(bo) {
m.SetUnknown(bo)
}
}
type fieldNum protoreflect.FieldNumber
func (n1 fieldNum) Has(n2 protoreflect.FieldNumber) bool {
return protoreflect.FieldNumber(n1) == n2
}