1 // Go support for Protocol Buffers - Google's data interchange format
3 // Copyright 2010 The Go Authors. All rights reserved.
4 // https://github.com/golang/protobuf
6 // Redistribution and use in source and binary forms, with or without
7 // modification, are permitted provided that the following conditions are
10 // * Redistributions of source code must retain the above copyright
11 // notice, this list of conditions and the following disclaimer.
12 // * Redistributions in binary form must reproduce the above
13 // copyright notice, this list of conditions and the following disclaimer
14 // in the documentation and/or other materials provided with the
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17 // contributors may be used to endorse or promote products derived from
18 // this software without specific prior written permission.
20 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 * Support for message sets.
47 // errNoMessageTypeID occurs when a protocol buffer does not have a message type ID.
48 // A message type ID is required for storing a protocol buffer in a message set.
49 var errNoMessageTypeID = errors.New("proto does not have a message type ID")
51 // The first two types (_MessageSet_Item and messageSet)
52 // model what the protocol compiler produces for the following protocol message:
53 // message MessageSet {
54 // repeated group Item = 1 {
55 // required int32 type_id = 2;
56 // required string message = 3;
59 // That is the MessageSet wire format. We can't use a proto to generate these
60 // because that would introduce a circular dependency between it and this package.
62 type _MessageSet_Item struct {
63 TypeId *int32 `protobuf:"varint,2,req,name=type_id"`
64 Message []byte `protobuf:"bytes,3,req,name=message"`
67 type messageSet struct {
68 Item []*_MessageSet_Item `protobuf:"group,1,rep"`
69 XXX_unrecognized []byte
73 // Make sure messageSet is a Message.
74 var _ Message = (*messageSet)(nil)
76 // messageTypeIder is an interface satisfied by a protocol buffer type
77 // that may be stored in a MessageSet.
78 type messageTypeIder interface {
82 func (ms *messageSet) find(pb Message) *_MessageSet_Item {
83 mti, ok := pb.(messageTypeIder)
87 id := mti.MessageTypeId()
88 for _, item := range ms.Item {
89 if *item.TypeId == id {
96 func (ms *messageSet) Has(pb Message) bool {
97 if ms.find(pb) != nil {
103 func (ms *messageSet) Unmarshal(pb Message) error {
104 if item := ms.find(pb); item != nil {
105 return Unmarshal(item.Message, pb)
107 if _, ok := pb.(messageTypeIder); !ok {
108 return errNoMessageTypeID
110 return nil // TODO: return error instead?
113 func (ms *messageSet) Marshal(pb Message) error {
114 msg, err := Marshal(pb)
118 if item := ms.find(pb); item != nil {
119 // reuse existing item
124 mti, ok := pb.(messageTypeIder)
126 return errNoMessageTypeID
129 mtid := mti.MessageTypeId()
130 ms.Item = append(ms.Item, &_MessageSet_Item{
137 func (ms *messageSet) Reset() { *ms = messageSet{} }
138 func (ms *messageSet) String() string { return CompactTextString(ms) }
139 func (*messageSet) ProtoMessage() {}
141 // Support for the message_set_wire_format message option.
143 func skipVarint(buf []byte) []byte {
145 for ; buf[i]&0x80 != 0; i++ {
150 // MarshalMessageSet encodes the extension map represented by m in the message set wire format.
151 // It is called by generated Marshal methods on protocol buffer messages with the message_set_wire_format option.
152 func MarshalMessageSet(exts interface{}) ([]byte, error) {
153 var m map[int32]Extension
154 switch exts := exts.(type) {
155 case *XXX_InternalExtensions:
156 if err := encodeExtensions(exts); err != nil {
159 m, _ = exts.extensionsRead()
160 case map[int32]Extension:
161 if err := encodeExtensionsMap(exts); err != nil {
166 return nil, errors.New("proto: not an extension map")
169 // Sort extension IDs to provide a deterministic encoding.
170 // See also enc_map in encode.go.
171 ids := make([]int, 0, len(m))
173 ids = append(ids, int(id))
177 ms := &messageSet{Item: make([]*_MessageSet_Item, 0, len(m))}
178 for _, id := range ids {
180 // Remove the wire type and field number varint, as well as the length varint.
181 msg := skipVarint(skipVarint(e.enc))
183 ms.Item = append(ms.Item, &_MessageSet_Item{
184 TypeId: Int32(int32(id)),
191 // UnmarshalMessageSet decodes the extension map encoded in buf in the message set wire format.
192 // It is called by generated Unmarshal methods on protocol buffer messages with the message_set_wire_format option.
193 func UnmarshalMessageSet(buf []byte, exts interface{}) error {
194 var m map[int32]Extension
195 switch exts := exts.(type) {
196 case *XXX_InternalExtensions:
197 m = exts.extensionsWrite()
198 case map[int32]Extension:
201 return errors.New("proto: not an extension map")
204 ms := new(messageSet)
205 if err := Unmarshal(buf, ms); err != nil {
208 for _, item := range ms.Item {
212 // Restore wire type and field number varint, plus length varint.
213 // Be careful to preserve duplicate items.
214 b := EncodeVarint(uint64(id)<<3 | WireBytes)
215 if ext, ok := m[id]; ok {
216 // Existing data; rip off the tag and length varint
217 // so we join the new data correctly.
218 // We can assume that ext.enc is set because we are unmarshaling.
219 o := ext.enc[len(b):] // skip wire type and field number
220 _, n := DecodeVarint(o) // calculate length of length varint
221 o = o[n:] // skip length varint
222 msg = append(o, msg...) // join old data and new data
224 b = append(b, EncodeVarint(uint64(len(msg)))...)
225 b = append(b, msg...)
227 m[id] = Extension{enc: b}
232 // MarshalMessageSetJSON encodes the extension map represented by m in JSON format.
233 // It is called by generated MarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
234 func MarshalMessageSetJSON(exts interface{}) ([]byte, error) {
235 var m map[int32]Extension
236 switch exts := exts.(type) {
237 case *XXX_InternalExtensions:
238 m, _ = exts.extensionsRead()
239 case map[int32]Extension:
242 return nil, errors.New("proto: not an extension map")
247 // Process the map in key order for deterministic output.
248 ids := make([]int32, 0, len(m))
250 ids = append(ids, id)
252 sort.Sort(int32Slice(ids)) // int32Slice defined in text.go
254 for i, id := range ids {
260 msd, ok := messageSetMap[id]
262 // Unknown type; we can't render it, so skip it.
265 fmt.Fprintf(&b, `"[%s]":`, msd.name)
269 x = reflect.New(msd.t.Elem()).Interface()
270 if err := Unmarshal(ext.enc, x.(Message)); err != nil {
274 d, err := json.Marshal(x)
281 return b.Bytes(), nil
284 // UnmarshalMessageSetJSON decodes the extension map encoded in buf in JSON format.
285 // It is called by generated UnmarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
286 func UnmarshalMessageSetJSON(buf []byte, exts interface{}) error {
287 // Common-case fast path.
288 if len(buf) == 0 || bytes.Equal(buf, []byte("{}")) {
292 // This is fairly tricky, and it's not clear that it is needed.
293 return errors.New("TODO: UnmarshalMessageSetJSON not yet implemented")
296 // A global registry of types that can be used in a MessageSet.
298 var messageSetMap = make(map[int32]messageSetDesc)
300 type messageSetDesc struct {
301 t reflect.Type // pointer to struct
305 // RegisterMessageSetType is called from the generated code.
306 func RegisterMessageSetType(m Message, fieldNum int32, name string) {
307 messageSetMap[fieldNum] = messageSetDesc{
308 t: reflect.TypeOf(m),