summaryrefslogtreecommitdiffstats
path: root/vendor/github.com/golang/protobuf/proto/properties.go
blob: ec2289c0058e47e3d20fa2bef7a3979529aa7512 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
// Go support for Protocol Buffers - Google's data interchange format
//
// Copyright 2010 The Go Authors.  All rights reserved.
// https://github.com/golang/protobuf
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package proto

/*
 * Routines for encoding data into the wire format for protocol buffers.
 */

import (
	"fmt"
	"log"
	"os"
	"reflect"
	"sort"
	"strconv"
	"strings"
	"sync"
)

const debug bool = false

// Constants that identify the encoding of a value on the wire.
const (
	WireVarint     = 0
	WireFixed64    = 1
	WireBytes      = 2
	WireStartGroup = 3
	WireEndGroup   = 4
	WireFixed32    = 5
)

const startSize = 10 // initial slice/string sizes

// Encoders are defined in encode.go
// An encoder outputs the full representation of a field, including its
// tag and encoder type.
type encoder func(p *Buffer, prop *Properties, base structPointer) error

// A valueEncoder encodes a single integer in a particular encoding.
type valueEncoder func(o *Buffer, x uint64) error

// Sizers are defined in encode.go
// A sizer returns the encoded size of a field, including its tag and encoder
// type.
type sizer func(prop *Properties, base structPointer) int

// A valueSizer returns the encoded size of a single integer in a particular
// encoding.
type valueSizer func(x uint64) int

// Decoders are defined in decode.go
// A decoder creates a value from its wire representation.
// Unrecognized subelements are saved in unrec.
type decoder func(p *Buffer, prop *Properties, base structPointer) error

// A valueDecoder decodes a single integer in a particular encoding.
type valueDecoder func(o *Buffer) (x uint64, err error)

// A oneofMarshaler does the marshaling for all oneof fields in a message.
type oneofMarshaler func(Message, *Buffer) error

// A oneofUnmarshaler does the unmarshaling for a oneof field in a message.
type oneofUnmarshaler func(Message, int, int, *Buffer) (bool, error)

// A oneofSizer does the sizing for all oneof fields in a message.
type oneofSizer func(Message) int

// tagMap is an optimization over map[int]int for typical protocol buffer
// use-cases. Encoded protocol buffers are often in tag order with small tag
// numbers.
type tagMap struct {
	fastTags []int
	slowTags map[int]int
}

// tagMapFastLimit is the upper bound on the tag number that will be stored in
// the tagMap slice rather than its map.
const tagMapFastLimit = 1024

func (p *tagMap) get(t int) (int, bool) {
	if t > 0 && t < tagMapFastLimit {
		if t >= len(p.fastTags) {
			return 0, false
		}
		fi := p.fastTags[t]
		return fi, fi >= 0
	}
	fi, ok := p.slowTags[t]
	return fi, ok
}

func (p *tagMap) put(t int, fi int) {
	if t > 0 && t < tagMapFastLimit {
		for len(p.fastTags) < t+1 {
			p.fastTags = append(p.fastTags, -1)
		}
		p.fastTags[t] = fi
		return
	}
	if p.slowTags == nil {
		p.slowTags = make(map[int]int)
	}
	p.slowTags[t] = fi
}

// StructProperties represents properties for all the fields of a struct.
// decoderTags and decoderOrigNames should only be used by the decoder.
type StructProperties struct {
	Prop             []*Properties  // properties for each field
	reqCount         int            // required count
	decoderTags      tagMap         // map from proto tag to struct field number
	decoderOrigNames map[string]int // map from original name to struct field number
	order            []int          // list of struct field numbers in tag order
	unrecField       field          // field id of the XXX_unrecognized []byte field
	extendable       bool           // is this an extendable proto

	oneofMarshaler   oneofMarshaler
	oneofUnmarshaler oneofUnmarshaler
	oneofSizer       oneofSizer
	stype            reflect.Type

	// OneofTypes contains information about the oneof fields in this message.
	// It is keyed by the original name of a field.
	OneofTypes map[string]*OneofProperties
}

// OneofProperties represents information about a specific field in a oneof.
type OneofProperties struct {
	Type  reflect.Type // pointer to generated struct type for this oneof field
	Field int          // struct field number of the containing oneof in the message
	Prop  *Properties
}

// Implement the sorting interface so we can sort the fields in tag order, as recommended by the spec.
// See encode.go, (*Buffer).enc_struct.

func (sp *StructProperties) Len() int { return len(sp.order) }
func (sp *StructProperties) Less(i, j int) bool {
	return sp.Prop[sp.order[i]].Tag < sp.Prop[sp.order[j]].Tag
}
func (sp *StructProperties) Swap(i, j int) { sp.order[i], sp.order[j] = sp.order[j], sp.order[i] }

// Properties represents the protocol-specific behavior of a single struct field.
type Properties struct {
	Name     string // name of the field, for error messages
	OrigName string // original name before protocol compiler (always set)
	JSONName string // name to use for JSON; determined by protoc
	Wire     string
	WireType int
	Tag      int
	Required bool
	Optional bool
	Repeated bool
	Packed   bool   // relevant for repeated primitives only
	Enum     string // set for enum types only
	proto3   bool   // whether this is known to be a proto3 field; set for []byte only
	oneof    bool   // whether this is a oneof field

	Default    string // default value
	HasDefault bool   // whether an explicit default was provided
	def_uint64 uint64

	enc           encoder
	valEnc        valueEncoder // set for bool and numeric types only
	field         field
	tagcode       []byte // encoding of EncodeVarint((Tag<<3)|WireType)
	tagbuf        [8]byte
	stype         reflect.Type      // set for struct types only
	sprop         *StructProperties // set for struct types only
	isMarshaler   bool
	isUnmarshaler bool

	mtype    reflect.Type // set for map types only
	mkeyprop *Properties  // set for map types only
	mvalprop *Properties  // set for map types only

	size    sizer
	valSize valueSizer // set for bool and numeric types only

	dec    decoder
	valDec valueDecoder // set for bool and numeric types only

	// If this is a packable field, this will be the decoder for the packed version of the field.
	packedDec decoder
}

// String formats the properties in the protobuf struct field tag style.
func (p *Properties) String() string {
	s := p.Wire
	s = ","
	s += strconv.Itoa(p.Tag)
	if p.Required {
		s += ",req"
	}
	if p.Optional {
		s += ",opt"
	}
	if p.Repeated {
		s += ",rep"
	}
	if p.Packed {
		s += ",packed"
	}
	s += ",name=" + p.OrigName
	if p.JSONName != p.OrigName {
		s += ",json=" + p.JSONName
	}
	if p.proto3 {
		s += ",proto3"
	}
	if p.oneof {
		s += ",oneof"
	}
	if len(p.Enum) > 0 {
		s += ",enum=" + p.Enum
	}
	if p.HasDefault {
		s += ",def=" + p.Default
	}
	return s
}

// Parse populates p by parsing a string in the protobuf struct field tag style.
func (p *Properties) Parse(s string) {
	// "bytes,49,opt,name=foo,def=hello!"
	fields := strings.Split(s, ",") // breaks def=, but handled below.
	if len(fields) < 2 {
		fmt.Fprintf(os.Stderr, "proto: tag has too few fields: %q\n", s)
		return
	}

	p.Wire = fields[0]
	switch p.Wire {
	case "varint":
		p.WireType = WireVarint
		p.valEnc = (*Buffer).EncodeVarint
		p.valDec = (*Buffer).DecodeVarint
		p.valSize = sizeVarint
	case "fixed32":
		p.WireType = WireFixed32
		p.valEnc = (*Buffer).EncodeFixed32
		p.valDec = (*Buffer).DecodeFixed32
		p.valSize = sizeFixed32
	case "fixed64":
		p.WireType = WireFixed64
		p.valEnc = (*Buffer).EncodeFixed64
		p.valDec = (*Buffer).DecodeFixed64
		p.valSize = sizeFixed64
	case "zigzag32":
		p.WireType = WireVarint
		p.valEnc = (*Buffer).EncodeZigzag32
		p.valDec = (*Buffer).DecodeZigzag32
		p.valSize = sizeZigzag32
	case "zigzag64":
		p.WireType = WireVarint
		p.valEnc = (*Buffer).EncodeZigzag64
		p.valDec = (*Buffer).DecodeZigzag64
		p.valSize = sizeZigzag64
	case "bytes", "group":
		p.WireType = WireBytes
		// no numeric converter for non-numeric types
	default:
		fmt.Fprintf(os.Stderr, "proto: tag has unknown wire type: %q\n", s)
		return
	}

	var err error
	p.Tag, err = strconv.Atoi(fields[1])
	if err != nil {
		return
	}

	for i := 2; i < len(fields); i++ {
		f := fields[i]
		switch {
		case f == "req":
			p.Required = true
		case f == "opt":
			p.Optional = true
		case f == "rep":
			p.Repeated = true
		case f == "packed":
			p.Packed = true
		case strings.HasPrefix(f, "name="):
			p.OrigName = f[5:]
		case strings.HasPrefix(f, "json="):
			p.JSONName = f[5:]
		case strings.HasPrefix(f, "enum="):
			p.Enum = f[5:]
		case f == "proto3":
			p.proto3 = true
		case f == "oneof":
			p.oneof = true
		case strings.HasPrefix(f, "def="):
			p.HasDefault = true
			p.Default = f[4:] // rest of string
			if i+1 < len(fields) {
				// Commas aren't escaped, and def is always last.
				p.Default += "," + strings.Join(fields[i+1:], ",")
				break
			}
		}
	}
}

func logNoSliceEnc(t1, t2 reflect.Type) {
	fmt.Fprintf(os.Stderr, "proto: no slice oenc for %T = []%T\n", t1, t2)
}

var protoMessageType = reflect.TypeOf((*Message)(nil)).Elem()

// Initialize the fields for encoding and decoding.
func (p *Properties) setEncAndDec(typ reflect.Type, f *reflect.StructField, lockGetProp bool) {
	p.enc = nil
	p.dec = nil
	p.size = nil

	switch t1 := typ; t1.Kind() {
	default:
		fmt.Fprintf(os.Stderr, "proto: no coders for %v\n", t1)

	// proto3 scalar types

	case reflect.Bool:
		p.enc = (*Buffer).enc_proto3_bool
		p.dec = (*Buffer).dec_proto3_bool
		p.size = size_proto3_bool
	case reflect.Int32:
		p.enc = (*Buffer).enc_proto3_int32
		p.dec = (*Buffer).dec_proto3_int32
		p.size = size_proto3_int32
	case reflect.Uint32:
		p.enc = (*Buffer).enc_proto3_uint32
		p.dec = (*Buffer).dec_proto3_int32 // can reuse
		p.size = size_proto3_uint32
	case reflect.Int64, reflect.Uint64:
		p.enc = (*Buffer).enc_proto3_int64
		p.dec = (*Buffer).dec_proto3_int64
		p.size = size_proto3_int64
	case reflect.Float32:
		p.enc = (*Buffer).enc_proto3_uint32 // can just treat them as bits
		p.dec = (*Buffer).dec_proto3_int32
		p.size = size_proto3_uint32
	case reflect.Float64:
		p.enc = (*Buffer).enc_proto3_int64 // can just treat them as bits
		p.dec = (*Buffer).dec_proto3_int64
		p.size = size_proto3_int64
	case reflect.String:
		p.enc = (*Buffer).enc_proto3_string
		p.dec = (*Buffer).dec_proto3_string
		p.size = size_proto3_string

	case reflect.Ptr:
		switch t2 := t1.Elem(); t2.Kind() {
		default:
			fmt.Fprintf(os.Stderr, "proto: no encoder function for %v -> %v\n", t1, t2)
			break
		case reflect.Bool:
			p.enc = (*Buffer).enc_bool
			p.dec = (*Buffer).dec_bool
			p.size = size_bool
		case reflect.Int32:
			p.enc = (*Buffer).enc_int32
			p.dec = (*Buffer).dec_int32
			p.size = size_int32
		case reflect.Uint32:
			p.enc = (*Buffer).enc_uint32
			p.dec = (*Buffer).dec_int32 // can reuse
			p.size = size_uint32
		case reflect.Int64, reflect.Uint64:
			p.enc = (*Buffer).enc_int64
			p.dec = (*Buffer).dec_int64
			p.size = size_int64
		case reflect.Float32:
			p.enc = (*Buffer).enc_uint32 // can just treat them as bits
			p.dec = (*Buffer).dec_int32
			p.size = size_uint32
		case reflect.Float64:
			p.enc = (*Buffer).enc_int64 // can just treat them as bits
			p.dec = (*Buffer).dec_int64
			p.size = size_int64
		case reflect.String:
			p.enc = (*Buffer).enc_string
			p.dec = (*Buffer).dec_string
			p.size = size_string
		case reflect.Struct:
			p.stype = t1.Elem()
			p.isMarshaler = isMarshaler(t1)
			p.isUnmarshaler = isUnmarshaler(t1)
			if p.Wire == "bytes" {
				p.enc = (*Buffer).enc_struct_message
				p.dec = (*Buffer).dec_struct_message
				p.size = size_struct_message
			} else {
				p.enc = (*Buffer).enc_struct_group
				p.dec = (*Buffer).dec_struct_group
				p.size = size_struct_group
			}
		}

	case reflect.Slice:
		switch t2 := t1.Elem(); t2.Kind() {
		default:
			logNoSliceEnc(t1, t2)
			break
		case reflect.Bool:
			if p.Packed {
				p.enc = (*Buffer).enc_slice_packed_bool
				p.size = size_slice_packed_bool
			} else {
				p.enc = (*Buffer).enc_slice_bool
				p.size = size_slice_bool
			}
			p.dec = (*Buffer).dec_slice_bool
			p.packedDec = (*Buffer).dec_slice_packed_bool
		case reflect.Int32:
			if p.Packed {
				p.enc = (*Buffer).enc_slice_packed_int32
				p.size = size_slice_packed_int32
			} else {
				p.enc = (*Buffer).enc_slice_int32
				p.size = size_slice_int32
			}
			p.dec = (*Buffer).dec_slice_int32
			p.packedDec = (*Buffer).dec_slice_packed_int32
		case reflect.Uint32:
			if p.Packed {
				p.enc = (*Buffer).enc_slice_packed_uint32
				p.size = size_slice_packed_uint32
			} else {
				p.enc = (*Buffer).enc_slice_uint32
				p.size = size_slice_uint32
			}
			p.dec = (*Buffer).dec_slice_int32
			p.packedDec = (*Buffer).dec_slice_packed_int32
		case reflect.Int64, reflect.Uint64:
			if p.Packed {
				p.enc = (*Buffer).enc_slice_packed_int64
				p.size = size_slice_packed_int64
			} else {
				p.enc = (*Buffer).enc_slice_int64
				p.size = size_slice_int64
			}
			p.dec = (*Buffer).dec_slice_int64
			p.packedDec = (*Buffer).dec_slice_packed_int64
		case reflect.Uint8:
			p.dec = (*Buffer).dec_slice_byte
			if p.proto3 {
				p.enc = (*Buffer).enc_proto3_slice_byte
				p.size = size_proto3_slice_byte
			} else {
				p.enc = (*Buffer).enc_slice_byte
				p.size = size_slice_byte
			}
		case reflect.Float32, reflect.Float64:
			switch t2.Bits() {
			case 32:
				// can just treat them as bits
				if p.Packed {
					p.enc = (*Buffer).enc_slice_packed_uint32
					p.size = size_slice_packed_uint32
				} else {
					p.enc = (*Buffer).enc_slice_uint32
					p.size = size_slice_uint32
				}
				p.dec = (*Buffer).dec_slice_int32
				p.packedDec = (*Buffer).dec_slice_packed_int32
			case 64:
				// can just treat them as bits
				if p.Packed {
					p.enc = (*Buffer).enc_slice_packed_int64
					p.size = size_slice_packed_int64
				} else {
					p.enc = (*Buffer).enc_slice_int64
					p.size = size_slice_int64
				}
				p.dec = (*Buffer).dec_slice_int64
				p.packedDec = (*Buffer).dec_slice_packed_int64
			default:
				logNoSliceEnc(t1, t2)
				break
			}
		case reflect.String:
			p.enc = (*Buffer).enc_slice_string
			p.dec = (*Buffer).dec_slice_string
			p.size = size_slice_string
		case reflect.Ptr:
			switch t3 := t2.Elem(); t3.Kind() {
			default:
				fmt.Fprintf(os.Stderr, "proto: no ptr oenc for %T -> %T -> %T\n", t1, t2, t3)
				break
			case reflect.Struct:
				p.stype = t2.Elem()
				p.isMarshaler = isMarshaler(t2)
				p.isUnmarshaler = isUnmarshaler(t2)
				if p.Wire == "bytes" {
					p.enc = (*Buffer).enc_slice_struct_message
					p.dec = (*Buffer).dec_slice_struct_message
					p.size = size_slice_struct_message
				} else {
					p.enc = (*Buffer).enc_slice_struct_group
					p.dec = (*Buffer).dec_slice_struct_group
					p.size = size_slice_struct_group
				}
			}
		case reflect.Slice:
			switch t2.Elem().Kind() {
			default:
				fmt.Fprintf(os.Stderr, "proto: no slice elem oenc for %T -> %T -> %T\n", t1, t2, t2.Elem())
				break
			case reflect.Uint8:
				p.enc = (*Buffer).enc_slice_slice_byte
				p.dec = (*Buffer).dec_slice_slice_byte
				p.size = size_slice_slice_byte
			}
		}

	case reflect.Map:
		p.enc = (*Buffer).enc_new_map
		p.dec = (*Buffer).dec_new_map
		p.size = size_new_map

		p.mtype = t1
		p.mkeyprop = &Properties{}
		p.mkeyprop.init(reflect.PtrTo(p.mtype.Key()), "Key", f.Tag.Get("protobuf_key"), nil, lockGetProp)
		p.mvalprop = &Properties{}
		vtype := p.mtype.Elem()
		if vtype.Kind() != reflect.Ptr && vtype.Kind() != reflect.Slice {
			// The value type is not a message (*T) or bytes ([]byte),
			// so we need encoders for the pointer to this type.
			vtype = reflect.PtrTo(vtype)
		}
		p.mvalprop.init(vtype, "Value", f.Tag.Get("protobuf_val"), nil, lockGetProp)
	}

	// precalculate tag code
	wire := p.WireType
	if p.Packed {
		wire = WireBytes
	}
	x := uint32(p.Tag)<<3 | uint32(wire)
	i := 0
	for i = 0; x > 127; i++ {
		p.tagbuf[i] = 0x80 | uint8(x&0x7F)
		x >>= 7
	}
	p.tagbuf[i] = uint8(x)
	p.tagcode = p.tagbuf[0 : i+1]

	if p.stype != nil {
		if lockGetProp {
			p.sprop = GetProperties(p.stype)
		} else {
			p.sprop = getPropertiesLocked(p.stype)
		}
	}
}

var (
	marshalerType   = reflect.TypeOf((*Marshaler)(nil)).Elem()
	unmarshalerType = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
)

// isMarshaler reports whether type t implements Marshaler.
func isMarshaler(t reflect.Type) bool {
	// We're checking for (likely) pointer-receiver methods
	// so if t is not a pointer, something is very wrong.
	// The calls above only invoke isMarshaler on pointer types.
	if t.Kind() != reflect.Ptr {
		panic("proto: misuse of isMarshaler")
	}
	return t.Implements(marshalerType)
}

// isUnmarshaler reports whether type t implements Unmarshaler.
func isUnmarshaler(t reflect.Type) bool {
	// We're checking for (likely) pointer-receiver methods
	// so if t is not a pointer, something is very wrong.
	// The calls above only invoke isUnmarshaler on pointer types.
	if t.Kind() != reflect.Ptr {
		panic("proto: misuse of isUnmarshaler")
	}
	return t.Implements(unmarshalerType)
}

// Init populates the properties from a protocol buffer struct tag.
func (p *Properties) Init(typ reflect.Type, name, tag string, f *reflect.StructField) {
	p.init(typ, name, tag, f, true)
}

func (p *Properties) init(typ reflect.Type, name, tag string, f *reflect.StructField, lockGetProp bool) {
	// "bytes,49,opt,def=hello!"
	p.Name = name
	p.OrigName = name
	if f != nil {
		p.field = toField(f)
	}
	if tag == "" {
		return
	}
	p.Parse(tag)
	p.setEncAndDec(typ, f, lockGetProp)
}

var (
	propertiesMu  sync.RWMutex
	propertiesMap = make(map[reflect.Type]*StructProperties)
)

// GetProperties returns the list of properties for the type represented by t.
// t must represent a generated struct type of a protocol message.
func GetProperties(t reflect.Type) *StructProperties {
	if t.Kind() != reflect.Struct {
		panic("proto: type must have kind struct")
	}

	// Most calls to GetProperties in a long-running program will be
	// retrieving details for types we have seen before.
	propertiesMu.RLock()
	sprop, ok := propertiesMap[t]
	propertiesMu.RUnlock()
	if ok {
		if collectStats {
			stats.Chit++
		}
		return sprop
	}

	propertiesMu.Lock()
	sprop = getPropertiesLocked(t)
	propertiesMu.Unlock()
	return sprop
}

// getPropertiesLocked requires that propertiesMu is held.
func getPropertiesLocked(t reflect.Type) *StructProperties {
	if prop, ok := propertiesMap[t]; ok {
		if collectStats {
			stats.Chit++
		}
		return prop
	}
	if collectStats {
		stats.Cmiss++
	}

	prop := new(StructProperties)
	// in case of recursive protos, fill this in now.
	propertiesMap[t] = prop

	// build properties
	prop.extendable = reflect.PtrTo(t).Implements(extendableProtoType) ||
		reflect.PtrTo(t).Implements(extendableProtoV1Type)
	prop.unrecField = invalidField
	prop.Prop = make([]*Properties, t.NumField())
	prop.order = make([]int, t.NumField())

	for i := 0; i < t.NumField(); i++ {
		f := t.Field(i)
		p := new(Properties)
		name := f.Name
		p.init(f.Type, name, f.Tag.Get("protobuf"), &f, false)

		if f.Name == "XXX_InternalExtensions" { // special case
			p.enc = (*Buffer).enc_exts
			p.dec = nil // not needed
			p.size = size_exts
		} else if f.Name == "XXX_extensions" { // special case
			p.enc = (*Buffer).enc_map
			p.dec = nil // not needed
			p.size = size_map
		} else if f.Name == "XXX_unrecognized" { // special case
			prop.unrecField = toField(&f)
		}
		oneof := f.Tag.Get("protobuf_oneof") // special case
		if oneof != "" {
			// Oneof fields don't use the traditional protobuf tag.
			p.OrigName = oneof
		}
		prop.Prop[i] = p
		prop.order[i] = i
		if debug {
			print(i, " ", f.Name, " ", t.String(), " ")
			if p.Tag > 0 {
				print(p.String())
			}
			print("\n")
		}
		if p.enc == nil && !strings.HasPrefix(f.Name, "XXX_") && oneof == "" {
			fmt.Fprintln(os.Stderr, "proto: no encoder for", f.Name, f.Type.String(), "[GetProperties]")
		}
	}

	// Re-order prop.order.
	sort.Sort(prop)

	type oneofMessage interface {
		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
	}
	if om, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(oneofMessage); ok {
		var oots []interface{}
		prop.oneofMarshaler, prop.oneofUnmarshaler, prop.oneofSizer, oots = om.XXX_OneofFuncs()
		prop.stype = t

		// Interpret oneof metadata.
		prop.OneofTypes = make(map[string]*OneofProperties)
		for _, oot := range oots {
			oop := &OneofProperties{
				Type: reflect.ValueOf(oot).Type(), // *T
				Prop: new(Properties),
			}
			sft := oop.Type.Elem().Field(0)
			oop.Prop.Name = sft.Name
			oop.Prop.Parse(sft.Tag.Get("protobuf"))
			// There will be exactly one interface field that
			// this new value is assignable to.
			for i := 0; i < t.NumField(); i++ {
				f := t.Field(i)
				if f.Type.Kind() != reflect.Interface {
					continue
				}
				if !oop.Type.AssignableTo(f.Type) {
					continue
				}
				oop.Field = i
				break
			}
			prop.OneofTypes[oop.Prop.OrigName] = oop
		}
	}

	// build required counts
	// build tags
	reqCount := 0
	prop.decoderOrigNames = make(map[string]int)
	for i, p := range prop.Prop {
		if strings.HasPrefix(p.Name, "XXX_") {
			// Internal fields should not appear in tags/origNames maps.
			// They are handled specially when encoding and decoding.
			continue
		}
		if p.Required {
			reqCount++
		}
		prop.decoderTags.put(p.Tag, i)
		prop.decoderOrigNames[p.OrigName] = i
	}
	prop.reqCount = reqCount

	return prop
}

// Return the Properties object for the x[0]'th field of the structure.
func propByIndex(t reflect.Type, x []int) *Properties {
	if len(x) != 1 {
		fmt.Fprintf(os.Stderr, "proto: field index dimension %d (not 1) for type %s\n", len(x), t)
		return nil
	}
	prop := GetProperties(t)
	return prop.Prop[x[0]]
}

// Get the address and type of a pointer to a struct from an interface.
func getbase(pb Message) (t reflect.Type, b structPointer, err error) {
	if pb == nil {
		err = ErrNil
		return
	}
	// get the reflect type of the pointer to the struct.
	t = reflect.TypeOf(pb)
	// get the address of the struct.
	value := reflect.ValueOf(pb)
	b = toStructPointer(value)
	return
}

// A global registry of enum types.
// The generated code will register the generated maps by calling RegisterEnum.

var enumValueMaps = make(map[string]map[string]int32)

// RegisterEnum is called from the generated code to install the enum descriptor
// maps into the global table to aid parsing text format protocol buffers.
func RegisterEnum(typeName string, unusedNameMap map[int32]string, valueMap map[string]int32) {
	if _, ok := enumValueMaps[typeName]; ok {
		panic("proto: duplicate enum registered: " + typeName)
	}
	enumValueMaps[typeName] = valueMap
}

// EnumValueMap returns the mapping from names to integers of the
// enum type enumType, or a nil if not found.
func EnumValueMap(enumType string) map[string]int32 {
	return enumValueMaps[enumType]
}

// A registry of all linked message types.
// The string is a fully-qualified proto name ("pkg.Message").
var (
	protoTypes    = make(map[string]reflect.Type)
	revProtoTypes = make(map[reflect.Type]string)
)

// RegisterType is called from generated code and maps from the fully qualified
// proto name to the type (pointer to struct) of the protocol buffer.
func RegisterType(x Message, name string) {
	if _, ok := protoTypes[name]; ok {
		// TODO: Some day, make this a panic.
		log.Printf("proto: duplicate proto type registered: %s", name)
		return
	}
	t := reflect.TypeOf(x)
	protoTypes[name] = t
	revProtoTypes[t] = name
}

// MessageName returns the fully-qualified proto name for the given message type.
func MessageName(x Message) string {
	type xname interface {
		XXX_MessageName() string
	}
	if m, ok := x.(xname); ok {
		return m.XXX_MessageName()
	}
	return revProtoTypes[reflect.TypeOf(x)]
}

// MessageType returns the message type (pointer to struct) for a named message.
func MessageType(name string) reflect.Type { return protoTypes[name] }

// A registry of all linked proto files.
var (
	protoFiles = make(map[string][]byte) // file name => fileDescriptor
)

// RegisterFile is called from generated code and maps from the
// full file name of a .proto file to its compressed FileDescriptorProto.
func RegisterFile(filename string, fileDescriptor []byte) {
	protoFiles[filename] = fileDescriptor
}

// FileDescriptor returns the compressed FileDescriptorProto for a .proto file.
func FileDescriptor(filename string) []byte { return protoFiles[filename] }