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// Copyright 2016 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 ptypes
import (
"fmt"
"strings"
"github.com/golang/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/reflect/protoregistry"
anypb "github.com/golang/protobuf/ptypes/any"
)
const urlPrefix = "type.googleapis.com/"
// AnyMessageName returns the message name contained in an anypb.Any message.
// Most type assertions should use the Is function instead.
func AnyMessageName(any *anypb.Any) (string, error) {
name, err := anyMessageName(any)
return string(name), err
}
func anyMessageName(any *anypb.Any) (protoreflect.FullName, error) {
if any == nil {
return "", fmt.Errorf("message is nil")
}
name := protoreflect.FullName(any.TypeUrl)
if i := strings.LastIndex(any.TypeUrl, "/"); i >= 0 {
name = name[i+len("/"):]
}
if !name.IsValid() {
return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl)
}
return name, nil
}
// MarshalAny marshals the given message m into an anypb.Any message.
func MarshalAny(m proto.Message) (*anypb.Any, error) {
switch dm := m.(type) {
case DynamicAny:
m = dm.Message
case *DynamicAny:
if dm == nil {
return nil, proto.ErrNil
}
m = dm.Message
}
b, err := proto.Marshal(m)
if err != nil {
return nil, err
}
return &anypb.Any{TypeUrl: urlPrefix + proto.MessageName(m), Value: b}, nil
}
// Empty returns a new message of the type specified in an anypb.Any message.
// It returns protoregistry.NotFound if the corresponding message type could not
// be resolved in the global registry.
func Empty(any *anypb.Any) (proto.Message, error) {
name, err := anyMessageName(any)
if err != nil {
return nil, err
}
mt, err := protoregistry.GlobalTypes.FindMessageByName(name)
if err != nil {
return nil, err
}
return proto.MessageV1(mt.New().Interface()), nil
}
// UnmarshalAny unmarshals the encoded value contained in the anypb.Any message
// into the provided message m. It returns an error if the target message
// does not match the type in the Any message or if an unmarshal error occurs.
//
// The target message m may be a *DynamicAny message. If the underlying message
// type could not be resolved, then this returns protoregistry.NotFound.
func UnmarshalAny(any *anypb.Any, m proto.Message) error {
if dm, ok := m.(*DynamicAny); ok {
if dm.Message == nil {
var err error
dm.Message, err = Empty(any)
if err != nil {
return err
}
}
m = dm.Message
}
anyName, err := AnyMessageName(any)
if err != nil {
return err
}
msgName := proto.MessageName(m)
if anyName != msgName {
return fmt.Errorf("mismatched message type: got %q want %q", anyName, msgName)
}
return proto.Unmarshal(any.Value, m)
}
// Is reports whether the Any message contains a message of the specified type.
func Is(any *anypb.Any, m proto.Message) bool {
if any == nil || m == nil {
return false
}
name := proto.MessageName(m)
if !strings.HasSuffix(any.TypeUrl, name) {
return false
}
return len(any.TypeUrl) == len(name) || any.TypeUrl[len(any.TypeUrl)-len(name)-1] == '/'
}
// DynamicAny is a value that can be passed to UnmarshalAny to automatically
// allocate a proto.Message for the type specified in an anypb.Any message.
// The allocated message is stored in the embedded proto.Message.
//
// Example:
// var x ptypes.DynamicAny
// if err := ptypes.UnmarshalAny(a, &x); err != nil { ... }
// fmt.Printf("unmarshaled message: %v", x.Message)
type DynamicAny struct{ proto.Message }
func (m DynamicAny) String() string {
if m.Message == nil {
return "<nil>"
}
return m.Message.String()
}
func (m DynamicAny) Reset() {
if m.Message == nil {
return
}
m.Message.Reset()
}
func (m DynamicAny) ProtoMessage() {
return
}
func (m DynamicAny) ProtoReflect() protoreflect.Message {
if m.Message == nil {
return nil
}
return dynamicAny{proto.MessageReflect(m.Message)}
}
type dynamicAny struct{ protoreflect.Message }
func (m dynamicAny) Type() protoreflect.MessageType {
return dynamicAnyType{m.Message.Type()}
}
func (m dynamicAny) New() protoreflect.Message {
return dynamicAnyType{m.Message.Type()}.New()
}
func (m dynamicAny) Interface() protoreflect.ProtoMessage {
return DynamicAny{proto.MessageV1(m.Message.Interface())}
}
type dynamicAnyType struct{ protoreflect.MessageType }
func (t dynamicAnyType) New() protoreflect.Message {
return dynamicAny{t.MessageType.New()}
}
func (t dynamicAnyType) Zero() protoreflect.Message {
return dynamicAny{t.MessageType.Zero()}
}