1// Copyright 2019 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 impl
6
7import (
8	"sort"
9
10	"google.golang.org/protobuf/encoding/protowire"
11	"google.golang.org/protobuf/internal/encoding/messageset"
12	"google.golang.org/protobuf/internal/errors"
13	"google.golang.org/protobuf/internal/flags"
14)
15
16func sizeMessageSet(mi *MessageInfo, p pointer, opts marshalOptions) (size int) {
17	if !flags.ProtoLegacy {
18		return 0
19	}
20
21	ext := *p.Apply(mi.extensionOffset).Extensions()
22	for _, x := range ext {
23		xi := getExtensionFieldInfo(x.Type())
24		if xi.funcs.size == nil {
25			continue
26		}
27		num, _ := protowire.DecodeTag(xi.wiretag)
28		size += messageset.SizeField(num)
29		size += xi.funcs.size(x.Value(), protowire.SizeTag(messageset.FieldMessage), opts)
30	}
31
32	unknown := *p.Apply(mi.unknownOffset).Bytes()
33	size += messageset.SizeUnknown(unknown)
34
35	return size
36}
37
38func marshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts marshalOptions) ([]byte, error) {
39	if !flags.ProtoLegacy {
40		return b, errors.New("no support for message_set_wire_format")
41	}
42
43	ext := *p.Apply(mi.extensionOffset).Extensions()
44	switch len(ext) {
45	case 0:
46	case 1:
47		// Fast-path for one extension: Don't bother sorting the keys.
48		for _, x := range ext {
49			var err error
50			b, err = marshalMessageSetField(mi, b, x, opts)
51			if err != nil {
52				return b, err
53			}
54		}
55	default:
56		// Sort the keys to provide a deterministic encoding.
57		// Not sure this is required, but the old code does it.
58		keys := make([]int, 0, len(ext))
59		for k := range ext {
60			keys = append(keys, int(k))
61		}
62		sort.Ints(keys)
63		for _, k := range keys {
64			var err error
65			b, err = marshalMessageSetField(mi, b, ext[int32(k)], opts)
66			if err != nil {
67				return b, err
68			}
69		}
70	}
71
72	unknown := *p.Apply(mi.unknownOffset).Bytes()
73	b, err := messageset.AppendUnknown(b, unknown)
74	if err != nil {
75		return b, err
76	}
77
78	return b, nil
79}
80
81func marshalMessageSetField(mi *MessageInfo, b []byte, x ExtensionField, opts marshalOptions) ([]byte, error) {
82	xi := getExtensionFieldInfo(x.Type())
83	num, _ := protowire.DecodeTag(xi.wiretag)
84	b = messageset.AppendFieldStart(b, num)
85	b, err := xi.funcs.marshal(b, x.Value(), protowire.EncodeTag(messageset.FieldMessage, protowire.BytesType), opts)
86	if err != nil {
87		return b, err
88	}
89	b = messageset.AppendFieldEnd(b)
90	return b, nil
91}
92
93func unmarshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts unmarshalOptions) (out unmarshalOutput, err error) {
94	if !flags.ProtoLegacy {
95		return out, errors.New("no support for message_set_wire_format")
96	}
97
98	ep := p.Apply(mi.extensionOffset).Extensions()
99	if *ep == nil {
100		*ep = make(map[int32]ExtensionField)
101	}
102	ext := *ep
103	unknown := p.Apply(mi.unknownOffset).Bytes()
104	initialized := true
105	err = messageset.Unmarshal(b, true, func(num protowire.Number, v []byte) error {
106		o, err := mi.unmarshalExtension(v, num, protowire.BytesType, ext, opts)
107		if err == errUnknown {
108			*unknown = protowire.AppendTag(*unknown, num, protowire.BytesType)
109			*unknown = append(*unknown, v...)
110			return nil
111		}
112		if !o.initialized {
113			initialized = false
114		}
115		return err
116	})
117	out.n = len(b)
118	out.initialized = initialized
119	return out, err
120}
121