1// Copyright 2016 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package ptypes
6
7import (
8	"fmt"
9	"strings"
10
11	"github.com/golang/protobuf/proto"
12	"google.golang.org/protobuf/reflect/protoreflect"
13	"google.golang.org/protobuf/reflect/protoregistry"
14
15	anypb "github.com/golang/protobuf/ptypes/any"
16)
17
18const urlPrefix = "type.googleapis.com/"
19
20// AnyMessageName returns the message name contained in an anypb.Any message.
21// Most type assertions should use the Is function instead.
22func AnyMessageName(any *anypb.Any) (string, error) {
23	name, err := anyMessageName(any)
24	return string(name), err
25}
26func anyMessageName(any *anypb.Any) (protoreflect.FullName, error) {
27	if any == nil {
28		return "", fmt.Errorf("message is nil")
29	}
30	name := protoreflect.FullName(any.TypeUrl)
31	if i := strings.LastIndex(any.TypeUrl, "/"); i >= 0 {
32		name = name[i+len("/"):]
33	}
34	if !name.IsValid() {
35		return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl)
36	}
37	return name, nil
38}
39
40// MarshalAny marshals the given message m into an anypb.Any message.
41func MarshalAny(m proto.Message) (*anypb.Any, error) {
42	switch dm := m.(type) {
43	case DynamicAny:
44		m = dm.Message
45	case *DynamicAny:
46		if dm == nil {
47			return nil, proto.ErrNil
48		}
49		m = dm.Message
50	}
51	b, err := proto.Marshal(m)
52	if err != nil {
53		return nil, err
54	}
55	return &anypb.Any{TypeUrl: urlPrefix + proto.MessageName(m), Value: b}, nil
56}
57
58// Empty returns a new message of the type specified in an anypb.Any message.
59// It returns protoregistry.NotFound if the corresponding message type could not
60// be resolved in the global registry.
61func Empty(any *anypb.Any) (proto.Message, error) {
62	name, err := anyMessageName(any)
63	if err != nil {
64		return nil, err
65	}
66	mt, err := protoregistry.GlobalTypes.FindMessageByName(name)
67	if err != nil {
68		return nil, err
69	}
70	return proto.MessageV1(mt.New().Interface()), nil
71}
72
73// UnmarshalAny unmarshals the encoded value contained in the anypb.Any message
74// into the provided message m. It returns an error if the target message
75// does not match the type in the Any message or if an unmarshal error occurs.
76//
77// The target message m may be a *DynamicAny message. If the underlying message
78// type could not be resolved, then this returns protoregistry.NotFound.
79func UnmarshalAny(any *anypb.Any, m proto.Message) error {
80	if dm, ok := m.(*DynamicAny); ok {
81		if dm.Message == nil {
82			var err error
83			dm.Message, err = Empty(any)
84			if err != nil {
85				return err
86			}
87		}
88		m = dm.Message
89	}
90
91	anyName, err := AnyMessageName(any)
92	if err != nil {
93		return err
94	}
95	msgName := proto.MessageName(m)
96	if anyName != msgName {
97		return fmt.Errorf("mismatched message type: got %q want %q", anyName, msgName)
98	}
99	return proto.Unmarshal(any.Value, m)
100}
101
102// Is reports whether the Any message contains a message of the specified type.
103func Is(any *anypb.Any, m proto.Message) bool {
104	if any == nil || m == nil {
105		return false
106	}
107	name := proto.MessageName(m)
108	if !strings.HasSuffix(any.TypeUrl, name) {
109		return false
110	}
111	return len(any.TypeUrl) == len(name) || any.TypeUrl[len(any.TypeUrl)-len(name)-1] == '/'
112}
113
114// DynamicAny is a value that can be passed to UnmarshalAny to automatically
115// allocate a proto.Message for the type specified in an anypb.Any message.
116// The allocated message is stored in the embedded proto.Message.
117//
118// Example:
119//   var x ptypes.DynamicAny
120//   if err := ptypes.UnmarshalAny(a, &x); err != nil { ... }
121//   fmt.Printf("unmarshaled message: %v", x.Message)
122type DynamicAny struct{ proto.Message }
123
124func (m DynamicAny) String() string {
125	if m.Message == nil {
126		return "<nil>"
127	}
128	return m.Message.String()
129}
130func (m DynamicAny) Reset() {
131	if m.Message == nil {
132		return
133	}
134	m.Message.Reset()
135}
136func (m DynamicAny) ProtoMessage() {
137	return
138}
139func (m DynamicAny) ProtoReflect() protoreflect.Message {
140	if m.Message == nil {
141		return nil
142	}
143	return dynamicAny{proto.MessageReflect(m.Message)}
144}
145
146type dynamicAny struct{ protoreflect.Message }
147
148func (m dynamicAny) Type() protoreflect.MessageType {
149	return dynamicAnyType{m.Message.Type()}
150}
151func (m dynamicAny) New() protoreflect.Message {
152	return dynamicAnyType{m.Message.Type()}.New()
153}
154func (m dynamicAny) Interface() protoreflect.ProtoMessage {
155	return DynamicAny{proto.MessageV1(m.Message.Interface())}
156}
157
158type dynamicAnyType struct{ protoreflect.MessageType }
159
160func (t dynamicAnyType) New() protoreflect.Message {
161	return dynamicAny{t.MessageType.New()}
162}
163func (t dynamicAnyType) Zero() protoreflect.Message {
164	return dynamicAny{t.MessageType.Zero()}
165}
166