blob: f710adab09246898d8c8dbee14a7268b27476246 [file] [log] [blame]
Matthias Andreas Benkard832a54e2019-01-29 09:27:38 +01001// Go support for Protocol Buffers - Google's data interchange format
2//
3// Copyright 2010 The Go Authors. All rights reserved.
4// https://github.com/golang/protobuf
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
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
15// distribution.
16// * Neither the name of Google Inc. nor the names of its
17// contributors may be used to endorse or promote products derived from
18// this software without specific prior written permission.
19//
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.
31
32package proto
33
34/*
35 * Routines for encoding data into the wire format for protocol buffers.
36 */
37
38import (
39 "fmt"
40 "log"
41 "os"
42 "reflect"
43 "sort"
44 "strconv"
45 "strings"
46 "sync"
47)
48
49const debug bool = false
50
51// Constants that identify the encoding of a value on the wire.
52const (
53 WireVarint = 0
54 WireFixed64 = 1
55 WireBytes = 2
56 WireStartGroup = 3
57 WireEndGroup = 4
58 WireFixed32 = 5
59)
60
61// tagMap is an optimization over map[int]int for typical protocol buffer
62// use-cases. Encoded protocol buffers are often in tag order with small tag
63// numbers.
64type tagMap struct {
65 fastTags []int
66 slowTags map[int]int
67}
68
69// tagMapFastLimit is the upper bound on the tag number that will be stored in
70// the tagMap slice rather than its map.
71const tagMapFastLimit = 1024
72
73func (p *tagMap) get(t int) (int, bool) {
74 if t > 0 && t < tagMapFastLimit {
75 if t >= len(p.fastTags) {
76 return 0, false
77 }
78 fi := p.fastTags[t]
79 return fi, fi >= 0
80 }
81 fi, ok := p.slowTags[t]
82 return fi, ok
83}
84
85func (p *tagMap) put(t int, fi int) {
86 if t > 0 && t < tagMapFastLimit {
87 for len(p.fastTags) < t+1 {
88 p.fastTags = append(p.fastTags, -1)
89 }
90 p.fastTags[t] = fi
91 return
92 }
93 if p.slowTags == nil {
94 p.slowTags = make(map[int]int)
95 }
96 p.slowTags[t] = fi
97}
98
99// StructProperties represents properties for all the fields of a struct.
100// decoderTags and decoderOrigNames should only be used by the decoder.
101type StructProperties struct {
102 Prop []*Properties // properties for each field
103 reqCount int // required count
104 decoderTags tagMap // map from proto tag to struct field number
105 decoderOrigNames map[string]int // map from original name to struct field number
106 order []int // list of struct field numbers in tag order
107
108 // OneofTypes contains information about the oneof fields in this message.
109 // It is keyed by the original name of a field.
110 OneofTypes map[string]*OneofProperties
111}
112
113// OneofProperties represents information about a specific field in a oneof.
114type OneofProperties struct {
115 Type reflect.Type // pointer to generated struct type for this oneof field
116 Field int // struct field number of the containing oneof in the message
117 Prop *Properties
118}
119
120// Implement the sorting interface so we can sort the fields in tag order, as recommended by the spec.
121// See encode.go, (*Buffer).enc_struct.
122
123func (sp *StructProperties) Len() int { return len(sp.order) }
124func (sp *StructProperties) Less(i, j int) bool {
125 return sp.Prop[sp.order[i]].Tag < sp.Prop[sp.order[j]].Tag
126}
127func (sp *StructProperties) Swap(i, j int) { sp.order[i], sp.order[j] = sp.order[j], sp.order[i] }
128
129// Properties represents the protocol-specific behavior of a single struct field.
130type Properties struct {
131 Name string // name of the field, for error messages
132 OrigName string // original name before protocol compiler (always set)
133 JSONName string // name to use for JSON; determined by protoc
134 Wire string
135 WireType int
136 Tag int
137 Required bool
138 Optional bool
139 Repeated bool
140 Packed bool // relevant for repeated primitives only
141 Enum string // set for enum types only
142 proto3 bool // whether this is known to be a proto3 field; set for []byte only
143 oneof bool // whether this is a oneof field
144
145 Default string // default value
146 HasDefault bool // whether an explicit default was provided
147
148 stype reflect.Type // set for struct types only
149 sprop *StructProperties // set for struct types only
150
151 mtype reflect.Type // set for map types only
152 mkeyprop *Properties // set for map types only
153 mvalprop *Properties // set for map types only
154}
155
156// String formats the properties in the protobuf struct field tag style.
157func (p *Properties) String() string {
158 s := p.Wire
159 s += ","
160 s += strconv.Itoa(p.Tag)
161 if p.Required {
162 s += ",req"
163 }
164 if p.Optional {
165 s += ",opt"
166 }
167 if p.Repeated {
168 s += ",rep"
169 }
170 if p.Packed {
171 s += ",packed"
172 }
173 s += ",name=" + p.OrigName
174 if p.JSONName != p.OrigName {
175 s += ",json=" + p.JSONName
176 }
177 if p.proto3 {
178 s += ",proto3"
179 }
180 if p.oneof {
181 s += ",oneof"
182 }
183 if len(p.Enum) > 0 {
184 s += ",enum=" + p.Enum
185 }
186 if p.HasDefault {
187 s += ",def=" + p.Default
188 }
189 return s
190}
191
192// Parse populates p by parsing a string in the protobuf struct field tag style.
193func (p *Properties) Parse(s string) {
194 // "bytes,49,opt,name=foo,def=hello!"
195 fields := strings.Split(s, ",") // breaks def=, but handled below.
196 if len(fields) < 2 {
197 fmt.Fprintf(os.Stderr, "proto: tag has too few fields: %q\n", s)
198 return
199 }
200
201 p.Wire = fields[0]
202 switch p.Wire {
203 case "varint":
204 p.WireType = WireVarint
205 case "fixed32":
206 p.WireType = WireFixed32
207 case "fixed64":
208 p.WireType = WireFixed64
209 case "zigzag32":
210 p.WireType = WireVarint
211 case "zigzag64":
212 p.WireType = WireVarint
213 case "bytes", "group":
214 p.WireType = WireBytes
215 // no numeric converter for non-numeric types
216 default:
217 fmt.Fprintf(os.Stderr, "proto: tag has unknown wire type: %q\n", s)
218 return
219 }
220
221 var err error
222 p.Tag, err = strconv.Atoi(fields[1])
223 if err != nil {
224 return
225 }
226
227outer:
228 for i := 2; i < len(fields); i++ {
229 f := fields[i]
230 switch {
231 case f == "req":
232 p.Required = true
233 case f == "opt":
234 p.Optional = true
235 case f == "rep":
236 p.Repeated = true
237 case f == "packed":
238 p.Packed = true
239 case strings.HasPrefix(f, "name="):
240 p.OrigName = f[5:]
241 case strings.HasPrefix(f, "json="):
242 p.JSONName = f[5:]
243 case strings.HasPrefix(f, "enum="):
244 p.Enum = f[5:]
245 case f == "proto3":
246 p.proto3 = true
247 case f == "oneof":
248 p.oneof = true
249 case strings.HasPrefix(f, "def="):
250 p.HasDefault = true
251 p.Default = f[4:] // rest of string
252 if i+1 < len(fields) {
253 // Commas aren't escaped, and def is always last.
254 p.Default += "," + strings.Join(fields[i+1:], ",")
255 break outer
256 }
257 }
258 }
259}
260
261var protoMessageType = reflect.TypeOf((*Message)(nil)).Elem()
262
263// setFieldProps initializes the field properties for submessages and maps.
264func (p *Properties) setFieldProps(typ reflect.Type, f *reflect.StructField, lockGetProp bool) {
265 switch t1 := typ; t1.Kind() {
266 case reflect.Ptr:
267 if t1.Elem().Kind() == reflect.Struct {
268 p.stype = t1.Elem()
269 }
270
271 case reflect.Slice:
272 if t2 := t1.Elem(); t2.Kind() == reflect.Ptr && t2.Elem().Kind() == reflect.Struct {
273 p.stype = t2.Elem()
274 }
275
276 case reflect.Map:
277 p.mtype = t1
278 p.mkeyprop = &Properties{}
279 p.mkeyprop.init(reflect.PtrTo(p.mtype.Key()), "Key", f.Tag.Get("protobuf_key"), nil, lockGetProp)
280 p.mvalprop = &Properties{}
281 vtype := p.mtype.Elem()
282 if vtype.Kind() != reflect.Ptr && vtype.Kind() != reflect.Slice {
283 // The value type is not a message (*T) or bytes ([]byte),
284 // so we need encoders for the pointer to this type.
285 vtype = reflect.PtrTo(vtype)
286 }
287 p.mvalprop.init(vtype, "Value", f.Tag.Get("protobuf_val"), nil, lockGetProp)
288 }
289
290 if p.stype != nil {
291 if lockGetProp {
292 p.sprop = GetProperties(p.stype)
293 } else {
294 p.sprop = getPropertiesLocked(p.stype)
295 }
296 }
297}
298
299var (
300 marshalerType = reflect.TypeOf((*Marshaler)(nil)).Elem()
301)
302
303// Init populates the properties from a protocol buffer struct tag.
304func (p *Properties) Init(typ reflect.Type, name, tag string, f *reflect.StructField) {
305 p.init(typ, name, tag, f, true)
306}
307
308func (p *Properties) init(typ reflect.Type, name, tag string, f *reflect.StructField, lockGetProp bool) {
309 // "bytes,49,opt,def=hello!"
310 p.Name = name
311 p.OrigName = name
312 if tag == "" {
313 return
314 }
315 p.Parse(tag)
316 p.setFieldProps(typ, f, lockGetProp)
317}
318
319var (
320 propertiesMu sync.RWMutex
321 propertiesMap = make(map[reflect.Type]*StructProperties)
322)
323
324// GetProperties returns the list of properties for the type represented by t.
325// t must represent a generated struct type of a protocol message.
326func GetProperties(t reflect.Type) *StructProperties {
327 if t.Kind() != reflect.Struct {
328 panic("proto: type must have kind struct")
329 }
330
331 // Most calls to GetProperties in a long-running program will be
332 // retrieving details for types we have seen before.
333 propertiesMu.RLock()
334 sprop, ok := propertiesMap[t]
335 propertiesMu.RUnlock()
336 if ok {
337 if collectStats {
338 stats.Chit++
339 }
340 return sprop
341 }
342
343 propertiesMu.Lock()
344 sprop = getPropertiesLocked(t)
345 propertiesMu.Unlock()
346 return sprop
347}
348
349// getPropertiesLocked requires that propertiesMu is held.
350func getPropertiesLocked(t reflect.Type) *StructProperties {
351 if prop, ok := propertiesMap[t]; ok {
352 if collectStats {
353 stats.Chit++
354 }
355 return prop
356 }
357 if collectStats {
358 stats.Cmiss++
359 }
360
361 prop := new(StructProperties)
362 // in case of recursive protos, fill this in now.
363 propertiesMap[t] = prop
364
365 // build properties
366 prop.Prop = make([]*Properties, t.NumField())
367 prop.order = make([]int, t.NumField())
368
369 for i := 0; i < t.NumField(); i++ {
370 f := t.Field(i)
371 p := new(Properties)
372 name := f.Name
373 p.init(f.Type, name, f.Tag.Get("protobuf"), &f, false)
374
375 oneof := f.Tag.Get("protobuf_oneof") // special case
376 if oneof != "" {
377 // Oneof fields don't use the traditional protobuf tag.
378 p.OrigName = oneof
379 }
380 prop.Prop[i] = p
381 prop.order[i] = i
382 if debug {
383 print(i, " ", f.Name, " ", t.String(), " ")
384 if p.Tag > 0 {
385 print(p.String())
386 }
387 print("\n")
388 }
389 }
390
391 // Re-order prop.order.
392 sort.Sort(prop)
393
394 type oneofMessage interface {
395 XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
396 }
397 if om, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(oneofMessage); ok {
398 var oots []interface{}
399 _, _, _, oots = om.XXX_OneofFuncs()
400
401 // Interpret oneof metadata.
402 prop.OneofTypes = make(map[string]*OneofProperties)
403 for _, oot := range oots {
404 oop := &OneofProperties{
405 Type: reflect.ValueOf(oot).Type(), // *T
406 Prop: new(Properties),
407 }
408 sft := oop.Type.Elem().Field(0)
409 oop.Prop.Name = sft.Name
410 oop.Prop.Parse(sft.Tag.Get("protobuf"))
411 // There will be exactly one interface field that
412 // this new value is assignable to.
413 for i := 0; i < t.NumField(); i++ {
414 f := t.Field(i)
415 if f.Type.Kind() != reflect.Interface {
416 continue
417 }
418 if !oop.Type.AssignableTo(f.Type) {
419 continue
420 }
421 oop.Field = i
422 break
423 }
424 prop.OneofTypes[oop.Prop.OrigName] = oop
425 }
426 }
427
428 // build required counts
429 // build tags
430 reqCount := 0
431 prop.decoderOrigNames = make(map[string]int)
432 for i, p := range prop.Prop {
433 if strings.HasPrefix(p.Name, "XXX_") {
434 // Internal fields should not appear in tags/origNames maps.
435 // They are handled specially when encoding and decoding.
436 continue
437 }
438 if p.Required {
439 reqCount++
440 }
441 prop.decoderTags.put(p.Tag, i)
442 prop.decoderOrigNames[p.OrigName] = i
443 }
444 prop.reqCount = reqCount
445
446 return prop
447}
448
449// A global registry of enum types.
450// The generated code will register the generated maps by calling RegisterEnum.
451
452var enumValueMaps = make(map[string]map[string]int32)
453
454// RegisterEnum is called from the generated code to install the enum descriptor
455// maps into the global table to aid parsing text format protocol buffers.
456func RegisterEnum(typeName string, unusedNameMap map[int32]string, valueMap map[string]int32) {
457 if _, ok := enumValueMaps[typeName]; ok {
458 panic("proto: duplicate enum registered: " + typeName)
459 }
460 enumValueMaps[typeName] = valueMap
461}
462
463// EnumValueMap returns the mapping from names to integers of the
464// enum type enumType, or a nil if not found.
465func EnumValueMap(enumType string) map[string]int32 {
466 return enumValueMaps[enumType]
467}
468
469// A registry of all linked message types.
470// The string is a fully-qualified proto name ("pkg.Message").
471var (
472 protoTypedNils = make(map[string]Message) // a map from proto names to typed nil pointers
473 protoMapTypes = make(map[string]reflect.Type) // a map from proto names to map types
474 revProtoTypes = make(map[reflect.Type]string)
475)
476
477// RegisterType is called from generated code and maps from the fully qualified
478// proto name to the type (pointer to struct) of the protocol buffer.
479func RegisterType(x Message, name string) {
480 if _, ok := protoTypedNils[name]; ok {
481 // TODO: Some day, make this a panic.
482 log.Printf("proto: duplicate proto type registered: %s", name)
483 return
484 }
485 t := reflect.TypeOf(x)
486 if v := reflect.ValueOf(x); v.Kind() == reflect.Ptr && v.Pointer() == 0 {
487 // Generated code always calls RegisterType with nil x.
488 // This check is just for extra safety.
489 protoTypedNils[name] = x
490 } else {
491 protoTypedNils[name] = reflect.Zero(t).Interface().(Message)
492 }
493 revProtoTypes[t] = name
494}
495
496// RegisterMapType is called from generated code and maps from the fully qualified
497// proto name to the native map type of the proto map definition.
498func RegisterMapType(x interface{}, name string) {
499 if reflect.TypeOf(x).Kind() != reflect.Map {
500 panic(fmt.Sprintf("RegisterMapType(%T, %q); want map", x, name))
501 }
502 if _, ok := protoMapTypes[name]; ok {
503 log.Printf("proto: duplicate proto type registered: %s", name)
504 return
505 }
506 t := reflect.TypeOf(x)
507 protoMapTypes[name] = t
508 revProtoTypes[t] = name
509}
510
511// MessageName returns the fully-qualified proto name for the given message type.
512func MessageName(x Message) string {
513 type xname interface {
514 XXX_MessageName() string
515 }
516 if m, ok := x.(xname); ok {
517 return m.XXX_MessageName()
518 }
519 return revProtoTypes[reflect.TypeOf(x)]
520}
521
522// MessageType returns the message type (pointer to struct) for a named message.
523// The type is not guaranteed to implement proto.Message if the name refers to a
524// map entry.
525func MessageType(name string) reflect.Type {
526 if t, ok := protoTypedNils[name]; ok {
527 return reflect.TypeOf(t)
528 }
529 return protoMapTypes[name]
530}
531
532// A registry of all linked proto files.
533var (
534 protoFiles = make(map[string][]byte) // file name => fileDescriptor
535)
536
537// RegisterFile is called from generated code and maps from the
538// full file name of a .proto file to its compressed FileDescriptorProto.
539func RegisterFile(filename string, fileDescriptor []byte) {
540 protoFiles[filename] = fileDescriptor
541}
542
543// FileDescriptor returns the compressed FileDescriptorProto for a .proto file.
544func FileDescriptor(filename string) []byte { return protoFiles[filename] }