aboutsummaryrefslogtreecommitdiffstats
path: root/vendor/google.golang.org/protobuf/compiler/protogen/protogen.go
blob: 431e88048a8fa05307d37cce39220dcbdbefad53 (plain) (blame)
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
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package protogen provides support for writing protoc plugins.
//
// Plugins for protoc, the Protocol Buffer compiler,
// are programs which read a CodeGeneratorRequest message from standard input
// and write a CodeGeneratorResponse message to standard output.
// This package provides support for writing plugins which generate Go code.
package protogen

import (
	"bufio"
	"bytes"
	"fmt"
	"go/ast"
	"go/parser"
	"go/printer"
	"go/token"
	"go/types"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"sort"
	"strconv"
	"strings"

	"google.golang.org/protobuf/encoding/prototext"
	"google.golang.org/protobuf/internal/genid"
	"google.golang.org/protobuf/internal/strs"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/reflect/protodesc"
	"google.golang.org/protobuf/reflect/protoreflect"
	"google.golang.org/protobuf/reflect/protoregistry"

	"google.golang.org/protobuf/types/descriptorpb"
	"google.golang.org/protobuf/types/dynamicpb"
	"google.golang.org/protobuf/types/pluginpb"
)

const goPackageDocURL = "https://protobuf.dev/reference/go/go-generated#package"

// Run executes a function as a protoc plugin.
//
// It reads a CodeGeneratorRequest message from os.Stdin, invokes the plugin
// function, and writes a CodeGeneratorResponse message to os.Stdout.
//
// If a failure occurs while reading or writing, Run prints an error to
// os.Stderr and calls os.Exit(1).
func (opts Options) Run(f func(*Plugin) error) {
	if err := run(opts, f); err != nil {
		fmt.Fprintf(os.Stderr, "%s: %v\n", filepath.Base(os.Args[0]), err)
		os.Exit(1)
	}
}

func run(opts Options, f func(*Plugin) error) error {
	if len(os.Args) > 1 {
		return fmt.Errorf("unknown argument %q (this program should be run by protoc, not directly)", os.Args[1])
	}
	in, err := ioutil.ReadAll(os.Stdin)
	if err != nil {
		return err
	}
	req := &pluginpb.CodeGeneratorRequest{}
	if err := proto.Unmarshal(in, req); err != nil {
		return err
	}
	gen, err := opts.New(req)
	if err != nil {
		return err
	}
	if err := f(gen); err != nil {
		// Errors from the plugin function are reported by setting the
		// error field in the CodeGeneratorResponse.
		//
		// In contrast, errors that indicate a problem in protoc
		// itself (unparsable input, I/O errors, etc.) are reported
		// to stderr.
		gen.Error(err)
	}
	resp := gen.Response()
	out, err := proto.Marshal(resp)
	if err != nil {
		return err
	}
	if _, err := os.Stdout.Write(out); err != nil {
		return err
	}
	return nil
}

// A Plugin is a protoc plugin invocation.
type Plugin struct {
	// Request is the CodeGeneratorRequest provided by protoc.
	Request *pluginpb.CodeGeneratorRequest

	// Files is the set of files to generate and everything they import.
	// Files appear in topological order, so each file appears before any
	// file that imports it.
	Files       []*File
	FilesByPath map[string]*File

	// SupportedFeatures is the set of protobuf language features supported by
	// this generator plugin. See the documentation for
	// google.protobuf.CodeGeneratorResponse.supported_features for details.
	SupportedFeatures uint64

	fileReg        *protoregistry.Files
	enumsByName    map[protoreflect.FullName]*Enum
	messagesByName map[protoreflect.FullName]*Message
	annotateCode   bool
	pathType       pathType
	module         string
	genFiles       []*GeneratedFile
	opts           Options
	err            error
}

type Options struct {
	// If ParamFunc is non-nil, it will be called with each unknown
	// generator parameter.
	//
	// Plugins for protoc can accept parameters from the command line,
	// passed in the --<lang>_out protoc, separated from the output
	// directory with a colon; e.g.,
	//
	//   --go_out=<param1>=<value1>,<param2>=<value2>:<output_directory>
	//
	// Parameters passed in this fashion as a comma-separated list of
	// key=value pairs will be passed to the ParamFunc.
	//
	// The (flag.FlagSet).Set method matches this function signature,
	// so parameters can be converted into flags as in the following:
	//
	//   var flags flag.FlagSet
	//   value := flags.Bool("param", false, "")
	//   opts := &protogen.Options{
	//     ParamFunc: flags.Set,
	//   }
	//   protogen.Run(opts, func(p *protogen.Plugin) error {
	//     if *value { ... }
	//   })
	ParamFunc func(name, value string) error

	// ImportRewriteFunc is called with the import path of each package
	// imported by a generated file. It returns the import path to use
	// for this package.
	ImportRewriteFunc func(GoImportPath) GoImportPath
}

// New returns a new Plugin.
func (opts Options) New(req *pluginpb.CodeGeneratorRequest) (*Plugin, error) {
	gen := &Plugin{
		Request:        req,
		FilesByPath:    make(map[string]*File),
		fileReg:        new(protoregistry.Files),
		enumsByName:    make(map[protoreflect.FullName]*Enum),
		messagesByName: make(map[protoreflect.FullName]*Message),
		opts:           opts,
	}

	packageNames := make(map[string]GoPackageName) // filename -> package name
	importPaths := make(map[string]GoImportPath)   // filename -> import path
	for _, param := range strings.Split(req.GetParameter(), ",") {
		var value string
		if i := strings.Index(param, "="); i >= 0 {
			value = param[i+1:]
			param = param[0:i]
		}
		switch param {
		case "":
			// Ignore.
		case "module":
			gen.module = value
		case "paths":
			switch value {
			case "import":
				gen.pathType = pathTypeImport
			case "source_relative":
				gen.pathType = pathTypeSourceRelative
			default:
				return nil, fmt.Errorf(`unknown path type %q: want "import" or "source_relative"`, value)
			}
		case "annotate_code":
			switch value {
			case "true", "":
				gen.annotateCode = true
			case "false":
			default:
				return nil, fmt.Errorf(`bad value for parameter %q: want "true" or "false"`, param)
			}
		default:
			if param[0] == 'M' {
				impPath, pkgName := splitImportPathAndPackageName(value)
				if pkgName != "" {
					packageNames[param[1:]] = pkgName
				}
				if impPath != "" {
					importPaths[param[1:]] = impPath
				}
				continue
			}
			if opts.ParamFunc != nil {
				if err := opts.ParamFunc(param, value); err != nil {
					return nil, err
				}
			}
		}
	}

	// When the module= option is provided, we strip the module name
	// prefix from generated files. This only makes sense if generated
	// filenames are based on the import path.
	if gen.module != "" && gen.pathType == pathTypeSourceRelative {
		return nil, fmt.Errorf("cannot use module= with paths=source_relative")
	}

	// Figure out the import path and package name for each file.
	//
	// The rules here are complicated and have grown organically over time.
	// Interactions between different ways of specifying package information
	// may be surprising.
	//
	// The recommended approach is to include a go_package option in every
	// .proto source file specifying the full import path of the Go package
	// associated with this file.
	//
	//     option go_package = "google.golang.org/protobuf/types/known/anypb";
	//
	// Alternatively, build systems which want to exert full control over
	// import paths may specify M<filename>=<import_path> flags.
	for _, fdesc := range gen.Request.ProtoFile {
		// The "M" command-line flags take precedence over
		// the "go_package" option in the .proto source file.
		filename := fdesc.GetName()
		impPath, pkgName := splitImportPathAndPackageName(fdesc.GetOptions().GetGoPackage())
		if importPaths[filename] == "" && impPath != "" {
			importPaths[filename] = impPath
		}
		if packageNames[filename] == "" && pkgName != "" {
			packageNames[filename] = pkgName
		}
		switch {
		case importPaths[filename] == "":
			// The import path must be specified one way or another.
			return nil, fmt.Errorf(
				"unable to determine Go import path for %q\n\n"+
					"Please specify either:\n"+
					"\t• a \"go_package\" option in the .proto source file, or\n"+
					"\t• a \"M\" argument on the command line.\n\n"+
					"See %v for more information.\n",
				fdesc.GetName(), goPackageDocURL)
		case !strings.Contains(string(importPaths[filename]), ".") &&
			!strings.Contains(string(importPaths[filename]), "/"):
			// Check that import paths contain at least a dot or slash to avoid
			// a common mistake where import path is confused with package name.
			return nil, fmt.Errorf(
				"invalid Go import path %q for %q\n\n"+
					"The import path must contain at least one period ('.') or forward slash ('/') character.\n\n"+
					"See %v for more information.\n",
				string(importPaths[filename]), fdesc.GetName(), goPackageDocURL)
		case packageNames[filename] == "":
			// If the package name is not explicitly specified,
			// then derive a reasonable package name from the import path.
			//
			// NOTE: The package name is derived first from the import path in
			// the "go_package" option (if present) before trying the "M" flag.
			// The inverted order for this is because the primary use of the "M"
			// flag is by build systems that have full control over the
			// import paths all packages, where it is generally expected that
			// the Go package name still be identical for the Go toolchain and
			// for custom build systems like Bazel.
			if impPath == "" {
				impPath = importPaths[filename]
			}
			packageNames[filename] = cleanPackageName(path.Base(string(impPath)))
		}
	}

	// Consistency check: Every file with the same Go import path should have
	// the same Go package name.
	packageFiles := make(map[GoImportPath][]string)
	for filename, importPath := range importPaths {
		if _, ok := packageNames[filename]; !ok {
			// Skip files mentioned in a M<file>=<import_path> parameter
			// but which do not appear in the CodeGeneratorRequest.
			continue
		}
		packageFiles[importPath] = append(packageFiles[importPath], filename)
	}
	for importPath, filenames := range packageFiles {
		for i := 1; i < len(filenames); i++ {
			if a, b := packageNames[filenames[0]], packageNames[filenames[i]]; a != b {
				return nil, fmt.Errorf("Go package %v has inconsistent names %v (%v) and %v (%v)",
					importPath, a, filenames[0], b, filenames[i])
			}
		}
	}

	// The extracted types from the full import set
	typeRegistry := newExtensionRegistry()
	for _, fdesc := range gen.Request.ProtoFile {
		filename := fdesc.GetName()
		if gen.FilesByPath[filename] != nil {
			return nil, fmt.Errorf("duplicate file name: %q", filename)
		}
		f, err := newFile(gen, fdesc, packageNames[filename], importPaths[filename])
		if err != nil {
			return nil, err
		}
		gen.Files = append(gen.Files, f)
		gen.FilesByPath[filename] = f
		if err = typeRegistry.registerAllExtensionsFromFile(f.Desc); err != nil {
			return nil, err
		}
	}
	for _, filename := range gen.Request.FileToGenerate {
		f, ok := gen.FilesByPath[filename]
		if !ok {
			return nil, fmt.Errorf("no descriptor for generated file: %v", filename)
		}
		f.Generate = true
	}

	// Create fully-linked descriptors if new extensions were found
	if typeRegistry.hasNovelExtensions() {
		for _, f := range gen.Files {
			b, err := proto.Marshal(f.Proto.ProtoReflect().Interface())
			if err != nil {
				return nil, err
			}
			err = proto.UnmarshalOptions{Resolver: typeRegistry}.Unmarshal(b, f.Proto)
			if err != nil {
				return nil, err
			}
		}
	}
	return gen, nil
}

// Error records an error in code generation. The generator will report the
// error back to protoc and will not produce output.
func (gen *Plugin) Error(err error) {
	if gen.err == nil {
		gen.err = err
	}
}

// Response returns the generator output.
func (gen *Plugin) Response() *pluginpb.CodeGeneratorResponse {
	resp := &pluginpb.CodeGeneratorResponse{}
	if gen.err != nil {
		resp.Error = proto.String(gen.err.Error())
		return resp
	}
	for _, g := range gen.genFiles {
		if g.skip {
			continue
		}
		content, err := g.Content()
		if err != nil {
			return &pluginpb.CodeGeneratorResponse{
				Error: proto.String(err.Error()),
			}
		}
		filename := g.filename
		if gen.module != "" {
			trim := gen.module + "/"
			if !strings.HasPrefix(filename, trim) {
				return &pluginpb.CodeGeneratorResponse{
					Error: proto.String(fmt.Sprintf("%v: generated file does not match prefix %q", filename, gen.module)),
				}
			}
			filename = strings.TrimPrefix(filename, trim)
		}
		resp.File = append(resp.File, &pluginpb.CodeGeneratorResponse_File{
			Name:    proto.String(filename),
			Content: proto.String(string(content)),
		})
		if gen.annotateCode && strings.HasSuffix(g.filename, ".go") {
			meta, err := g.metaFile(content)
			if err != nil {
				return &pluginpb.CodeGeneratorResponse{
					Error: proto.String(err.Error()),
				}
			}
			resp.File = append(resp.File, &pluginpb.CodeGeneratorResponse_File{
				Name:    proto.String(filename + ".meta"),
				Content: proto.String(meta),
			})
		}
	}
	if gen.SupportedFeatures > 0 {
		resp.SupportedFeatures = proto.Uint64(gen.SupportedFeatures)
	}
	return resp
}

// A File describes a .proto source file.
type File struct {
	Desc  protoreflect.FileDescriptor
	Proto *descriptorpb.FileDescriptorProto

	GoDescriptorIdent GoIdent       // name of Go variable for the file descriptor
	GoPackageName     GoPackageName // name of this file's Go package
	GoImportPath      GoImportPath  // import path of this file's Go package

	Enums      []*Enum      // top-level enum declarations
	Messages   []*Message   // top-level message declarations
	Extensions []*Extension // top-level extension declarations
	Services   []*Service   // top-level service declarations

	Generate bool // true if we should generate code for this file

	// GeneratedFilenamePrefix is used to construct filenames for generated
	// files associated with this source file.
	//
	// For example, the source file "dir/foo.proto" might have a filename prefix
	// of "dir/foo". Appending ".pb.go" produces an output file of "dir/foo.pb.go".
	GeneratedFilenamePrefix string

	location Location
}

func newFile(gen *Plugin, p *descriptorpb.FileDescriptorProto, packageName GoPackageName, importPath GoImportPath) (*File, error) {
	desc, err := protodesc.NewFile(p, gen.fileReg)
	if err != nil {
		return nil, fmt.Errorf("invalid FileDescriptorProto %q: %v", p.GetName(), err)
	}
	if err := gen.fileReg.RegisterFile(desc); err != nil {
		return nil, fmt.Errorf("cannot register descriptor %q: %v", p.GetName(), err)
	}
	f := &File{
		Desc:          desc,
		Proto:         p,
		GoPackageName: packageName,
		GoImportPath:  importPath,
		location:      Location{SourceFile: desc.Path()},
	}

	// Determine the prefix for generated Go files.
	prefix := p.GetName()
	if ext := path.Ext(prefix); ext == ".proto" || ext == ".protodevel" {
		prefix = prefix[:len(prefix)-len(ext)]
	}
	switch gen.pathType {
	case pathTypeImport:
		// If paths=import, the output filename is derived from the Go import path.
		prefix = path.Join(string(f.GoImportPath), path.Base(prefix))
	case pathTypeSourceRelative:
		// If paths=source_relative, the output filename is derived from
		// the input filename.
	}
	f.GoDescriptorIdent = GoIdent{
		GoName:       "File_" + strs.GoSanitized(p.GetName()),
		GoImportPath: f.GoImportPath,
	}
	f.GeneratedFilenamePrefix = prefix

	for i, eds := 0, desc.Enums(); i < eds.Len(); i++ {
		f.Enums = append(f.Enums, newEnum(gen, f, nil, eds.Get(i)))
	}
	for i, mds := 0, desc.Messages(); i < mds.Len(); i++ {
		f.Messages = append(f.Messages, newMessage(gen, f, nil, mds.Get(i)))
	}
	for i, xds := 0, desc.Extensions(); i < xds.Len(); i++ {
		f.Extensions = append(f.Extensions, newField(gen, f, nil, xds.Get(i)))
	}
	for i, sds := 0, desc.Services(); i < sds.Len(); i++ {
		f.Services = append(f.Services, newService(gen, f, sds.Get(i)))
	}
	for _, message := range f.Messages {
		if err := message.resolveDependencies(gen); err != nil {
			return nil, err
		}
	}
	for _, extension := range f.Extensions {
		if err := extension.resolveDependencies(gen); err != nil {
			return nil, err
		}
	}
	for _, service := range f.Services {
		for _, method := range service.Methods {
			if err := method.resolveDependencies(gen); err != nil {
				return nil, err
			}
		}
	}
	return f, nil
}

// splitImportPathAndPackageName splits off the optional Go package name
// from the Go import path when separated by a ';' delimiter.
func splitImportPathAndPackageName(s string) (GoImportPath, GoPackageName) {
	if i := strings.Index(s, ";"); i >= 0 {
		return GoImportPath(s[:i]), GoPackageName(s[i+1:])
	}
	return GoImportPath(s), ""
}

// An Enum describes an enum.
type Enum struct {
	Desc protoreflect.EnumDescriptor

	GoIdent GoIdent // name of the generated Go type

	Values []*EnumValue // enum value declarations

	Location Location   // location of this enum
	Comments CommentSet // comments associated with this enum
}

func newEnum(gen *Plugin, f *File, parent *Message, desc protoreflect.EnumDescriptor) *Enum {
	var loc Location
	if parent != nil {
		loc = parent.Location.appendPath(genid.DescriptorProto_EnumType_field_number, desc.Index())
	} else {
		loc = f.location.appendPath(genid.FileDescriptorProto_EnumType_field_number, desc.Index())
	}
	enum := &Enum{
		Desc:     desc,
		GoIdent:  newGoIdent(f, desc),
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
	gen.enumsByName[desc.FullName()] = enum
	for i, vds := 0, enum.Desc.Values(); i < vds.Len(); i++ {
		enum.Values = append(enum.Values, newEnumValue(gen, f, parent, enum, vds.Get(i)))
	}
	return enum
}

// An EnumValue describes an enum value.
type EnumValue struct {
	Desc protoreflect.EnumValueDescriptor

	GoIdent GoIdent // name of the generated Go declaration

	Parent *Enum // enum in which this value is declared

	Location Location   // location of this enum value
	Comments CommentSet // comments associated with this enum value
}

func newEnumValue(gen *Plugin, f *File, message *Message, enum *Enum, desc protoreflect.EnumValueDescriptor) *EnumValue {
	// A top-level enum value's name is: EnumName_ValueName
	// An enum value contained in a message is: MessageName_ValueName
	//
	// For historical reasons, enum value names are not camel-cased.
	parentIdent := enum.GoIdent
	if message != nil {
		parentIdent = message.GoIdent
	}
	name := parentIdent.GoName + "_" + string(desc.Name())
	loc := enum.Location.appendPath(genid.EnumDescriptorProto_Value_field_number, desc.Index())
	return &EnumValue{
		Desc:     desc,
		GoIdent:  f.GoImportPath.Ident(name),
		Parent:   enum,
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
}

// A Message describes a message.
type Message struct {
	Desc protoreflect.MessageDescriptor

	GoIdent GoIdent // name of the generated Go type

	Fields []*Field // message field declarations
	Oneofs []*Oneof // message oneof declarations

	Enums      []*Enum      // nested enum declarations
	Messages   []*Message   // nested message declarations
	Extensions []*Extension // nested extension declarations

	Location Location   // location of this message
	Comments CommentSet // comments associated with this message
}

func newMessage(gen *Plugin, f *File, parent *Message, desc protoreflect.MessageDescriptor) *Message {
	var loc Location
	if parent != nil {
		loc = parent.Location.appendPath(genid.DescriptorProto_NestedType_field_number, desc.Index())
	} else {
		loc = f.location.appendPath(genid.FileDescriptorProto_MessageType_field_number, desc.Index())
	}
	message := &Message{
		Desc:     desc,
		GoIdent:  newGoIdent(f, desc),
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
	gen.messagesByName[desc.FullName()] = message
	for i, eds := 0, desc.Enums(); i < eds.Len(); i++ {
		message.Enums = append(message.Enums, newEnum(gen, f, message, eds.Get(i)))
	}
	for i, mds := 0, desc.Messages(); i < mds.Len(); i++ {
		message.Messages = append(message.Messages, newMessage(gen, f, message, mds.Get(i)))
	}
	for i, fds := 0, desc.Fields(); i < fds.Len(); i++ {
		message.Fields = append(message.Fields, newField(gen, f, message, fds.Get(i)))
	}
	for i, ods := 0, desc.Oneofs(); i < ods.Len(); i++ {
		message.Oneofs = append(message.Oneofs, newOneof(gen, f, message, ods.Get(i)))
	}
	for i, xds := 0, desc.Extensions(); i < xds.Len(); i++ {
		message.Extensions = append(message.Extensions, newField(gen, f, message, xds.Get(i)))
	}

	// Resolve local references between fields and oneofs.
	for _, field := range message.Fields {
		if od := field.Desc.ContainingOneof(); od != nil {
			oneof := message.Oneofs[od.Index()]
			field.Oneof = oneof
			oneof.Fields = append(oneof.Fields, field)
		}
	}

	// Field name conflict resolution.
	//
	// We assume well-known method names that may be attached to a generated
	// message type, as well as a 'Get*' method for each field. For each
	// field in turn, we add _s to its name until there are no conflicts.
	//
	// Any change to the following set of method names is a potential
	// incompatible API change because it may change generated field names.
	//
	// TODO: If we ever support a 'go_name' option to set the Go name of a
	// field, we should consider dropping this entirely. The conflict
	// resolution algorithm is subtle and surprising (changing the order
	// in which fields appear in the .proto source file can change the
	// names of fields in generated code), and does not adapt well to
	// adding new per-field methods such as setters.
	usedNames := map[string]bool{
		"Reset":               true,
		"String":              true,
		"ProtoMessage":        true,
		"Marshal":             true,
		"Unmarshal":           true,
		"ExtensionRangeArray": true,
		"ExtensionMap":        true,
		"Descriptor":          true,
	}
	makeNameUnique := func(name string, hasGetter bool) string {
		for usedNames[name] || (hasGetter && usedNames["Get"+name]) {
			name += "_"
		}
		usedNames[name] = true
		usedNames["Get"+name] = hasGetter
		return name
	}
	for _, field := range message.Fields {
		field.GoName = makeNameUnique(field.GoName, true)
		field.GoIdent.GoName = message.GoIdent.GoName + "_" + field.GoName
		if field.Oneof != nil && field.Oneof.Fields[0] == field {
			// Make the name for a oneof unique as well. For historical reasons,
			// this assumes that a getter method is not generated for oneofs.
			// This is incorrect, but fixing it breaks existing code.
			field.Oneof.GoName = makeNameUnique(field.Oneof.GoName, false)
			field.Oneof.GoIdent.GoName = message.GoIdent.GoName + "_" + field.Oneof.GoName
		}
	}

	// Oneof field name conflict resolution.
	//
	// This conflict resolution is incomplete as it does not consider collisions
	// with other oneof field types, but fixing it breaks existing code.
	for _, field := range message.Fields {
		if field.Oneof != nil {
		Loop:
			for {
				for _, nestedMessage := range message.Messages {
					if nestedMessage.GoIdent == field.GoIdent {
						field.GoIdent.GoName += "_"
						continue Loop
					}
				}
				for _, nestedEnum := range message.Enums {
					if nestedEnum.GoIdent == field.GoIdent {
						field.GoIdent.GoName += "_"
						continue Loop
					}
				}
				break Loop
			}
		}
	}

	return message
}

func (message *Message) resolveDependencies(gen *Plugin) error {
	for _, field := range message.Fields {
		if err := field.resolveDependencies(gen); err != nil {
			return err
		}
	}
	for _, message := range message.Messages {
		if err := message.resolveDependencies(gen); err != nil {
			return err
		}
	}
	for _, extension := range message.Extensions {
		if err := extension.resolveDependencies(gen); err != nil {
			return err
		}
	}
	return nil
}

// A Field describes a message field.
type Field struct {
	Desc protoreflect.FieldDescriptor

	// GoName is the base name of this field's Go field and methods.
	// For code generated by protoc-gen-go, this means a field named
	// '{{GoName}}' and a getter method named 'Get{{GoName}}'.
	GoName string // e.g., "FieldName"

	// GoIdent is the base name of a top-level declaration for this field.
	// For code generated by protoc-gen-go, this means a wrapper type named
	// '{{GoIdent}}' for members fields of a oneof, and a variable named
	// 'E_{{GoIdent}}' for extension fields.
	GoIdent GoIdent // e.g., "MessageName_FieldName"

	Parent   *Message // message in which this field is declared; nil if top-level extension
	Oneof    *Oneof   // containing oneof; nil if not part of a oneof
	Extendee *Message // extended message for extension fields; nil otherwise

	Enum    *Enum    // type for enum fields; nil otherwise
	Message *Message // type for message or group fields; nil otherwise

	Location Location   // location of this field
	Comments CommentSet // comments associated with this field
}

func newField(gen *Plugin, f *File, message *Message, desc protoreflect.FieldDescriptor) *Field {
	var loc Location
	switch {
	case desc.IsExtension() && message == nil:
		loc = f.location.appendPath(genid.FileDescriptorProto_Extension_field_number, desc.Index())
	case desc.IsExtension() && message != nil:
		loc = message.Location.appendPath(genid.DescriptorProto_Extension_field_number, desc.Index())
	default:
		loc = message.Location.appendPath(genid.DescriptorProto_Field_field_number, desc.Index())
	}
	camelCased := strs.GoCamelCase(string(desc.Name()))
	var parentPrefix string
	if message != nil {
		parentPrefix = message.GoIdent.GoName + "_"
	}
	field := &Field{
		Desc:   desc,
		GoName: camelCased,
		GoIdent: GoIdent{
			GoImportPath: f.GoImportPath,
			GoName:       parentPrefix + camelCased,
		},
		Parent:   message,
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
	return field
}

func (field *Field) resolveDependencies(gen *Plugin) error {
	desc := field.Desc
	switch desc.Kind() {
	case protoreflect.EnumKind:
		name := field.Desc.Enum().FullName()
		enum, ok := gen.enumsByName[name]
		if !ok {
			return fmt.Errorf("field %v: no descriptor for enum %v", desc.FullName(), name)
		}
		field.Enum = enum
	case protoreflect.MessageKind, protoreflect.GroupKind:
		name := desc.Message().FullName()
		message, ok := gen.messagesByName[name]
		if !ok {
			return fmt.Errorf("field %v: no descriptor for type %v", desc.FullName(), name)
		}
		field.Message = message
	}
	if desc.IsExtension() {
		name := desc.ContainingMessage().FullName()
		message, ok := gen.messagesByName[name]
		if !ok {
			return fmt.Errorf("field %v: no descriptor for type %v", desc.FullName(), name)
		}
		field.Extendee = message
	}
	return nil
}

// A Oneof describes a message oneof.
type Oneof struct {
	Desc protoreflect.OneofDescriptor

	// GoName is the base name of this oneof's Go field and methods.
	// For code generated by protoc-gen-go, this means a field named
	// '{{GoName}}' and a getter method named 'Get{{GoName}}'.
	GoName string // e.g., "OneofName"

	// GoIdent is the base name of a top-level declaration for this oneof.
	GoIdent GoIdent // e.g., "MessageName_OneofName"

	Parent *Message // message in which this oneof is declared

	Fields []*Field // fields that are part of this oneof

	Location Location   // location of this oneof
	Comments CommentSet // comments associated with this oneof
}

func newOneof(gen *Plugin, f *File, message *Message, desc protoreflect.OneofDescriptor) *Oneof {
	loc := message.Location.appendPath(genid.DescriptorProto_OneofDecl_field_number, desc.Index())
	camelCased := strs.GoCamelCase(string(desc.Name()))
	parentPrefix := message.GoIdent.GoName + "_"
	return &Oneof{
		Desc:   desc,
		Parent: message,
		GoName: camelCased,
		GoIdent: GoIdent{
			GoImportPath: f.GoImportPath,
			GoName:       parentPrefix + camelCased,
		},
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
}

// Extension is an alias of Field for documentation.
type Extension = Field

// A Service describes a service.
type Service struct {
	Desc protoreflect.ServiceDescriptor

	GoName string

	Methods []*Method // service method declarations

	Location Location   // location of this service
	Comments CommentSet // comments associated with this service
}

func newService(gen *Plugin, f *File, desc protoreflect.ServiceDescriptor) *Service {
	loc := f.location.appendPath(genid.FileDescriptorProto_Service_field_number, desc.Index())
	service := &Service{
		Desc:     desc,
		GoName:   strs.GoCamelCase(string(desc.Name())),
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
	for i, mds := 0, desc.Methods(); i < mds.Len(); i++ {
		service.Methods = append(service.Methods, newMethod(gen, f, service, mds.Get(i)))
	}
	return service
}

// A Method describes a method in a service.
type Method struct {
	Desc protoreflect.MethodDescriptor

	GoName string

	Parent *Service // service in which this method is declared

	Input  *Message
	Output *Message

	Location Location   // location of this method
	Comments CommentSet // comments associated with this method
}

func newMethod(gen *Plugin, f *File, service *Service, desc protoreflect.MethodDescriptor) *Method {
	loc := service.Location.appendPath(genid.ServiceDescriptorProto_Method_field_number, desc.Index())
	method := &Method{
		Desc:     desc,
		GoName:   strs.GoCamelCase(string(desc.Name())),
		Parent:   service,
		Location: loc,
		Comments: makeCommentSet(f.Desc.SourceLocations().ByDescriptor(desc)),
	}
	return method
}

func (method *Method) resolveDependencies(gen *Plugin) error {
	desc := method.Desc

	inName := desc.Input().FullName()
	in, ok := gen.messagesByName[inName]
	if !ok {
		return fmt.Errorf("method %v: no descriptor for type %v", desc.FullName(), inName)
	}
	method.Input = in

	outName := desc.Output().FullName()
	out, ok := gen.messagesByName[outName]
	if !ok {
		return fmt.Errorf("method %v: no descriptor for type %v", desc.FullName(), outName)
	}
	method.Output = out

	return nil
}

// A GeneratedFile is a generated file.
type GeneratedFile struct {
	gen              *Plugin
	skip             bool
	filename         string
	goImportPath     GoImportPath
	buf              bytes.Buffer
	packageNames     map[GoImportPath]GoPackageName
	usedPackageNames map[GoPackageName]bool
	manualImports    map[GoImportPath]bool
	annotations      map[string][]Annotation
}

// NewGeneratedFile creates a new generated file with the given filename
// and import path.
func (gen *Plugin) NewGeneratedFile(filename string, goImportPath GoImportPath) *GeneratedFile {
	g := &GeneratedFile{
		gen:              gen,
		filename:         filename,
		goImportPath:     goImportPath,
		packageNames:     make(map[GoImportPath]GoPackageName),
		usedPackageNames: make(map[GoPackageName]bool),
		manualImports:    make(map[GoImportPath]bool),
		annotations:      make(map[string][]Annotation),
	}

	// All predeclared identifiers in Go are already used.
	for _, s := range types.Universe.Names() {
		g.usedPackageNames[GoPackageName(s)] = true
	}

	gen.genFiles = append(gen.genFiles, g)
	return g
}

// P prints a line to the generated output. It converts each parameter to a
// string following the same rules as fmt.Print. It never inserts spaces
// between parameters.
func (g *GeneratedFile) P(v ...interface{}) {
	for _, x := range v {
		switch x := x.(type) {
		case GoIdent:
			fmt.Fprint(&g.buf, g.QualifiedGoIdent(x))
		default:
			fmt.Fprint(&g.buf, x)
		}
	}
	fmt.Fprintln(&g.buf)
}

// QualifiedGoIdent returns the string to use for a Go identifier.
//
// If the identifier is from a different Go package than the generated file,
// the returned name will be qualified (package.name) and an import statement
// for the identifier's package will be included in the file.
func (g *GeneratedFile) QualifiedGoIdent(ident GoIdent) string {
	if ident.GoImportPath == g.goImportPath {
		return ident.GoName
	}
	if packageName, ok := g.packageNames[ident.GoImportPath]; ok {
		return string(packageName) + "." + ident.GoName
	}
	packageName := cleanPackageName(path.Base(string(ident.GoImportPath)))
	for i, orig := 1, packageName; g.usedPackageNames[packageName]; i++ {
		packageName = orig + GoPackageName(strconv.Itoa(i))
	}
	g.packageNames[ident.GoImportPath] = packageName
	g.usedPackageNames[packageName] = true
	return string(packageName) + "." + ident.GoName
}

// Import ensures a package is imported by the generated file.
//
// Packages referenced by QualifiedGoIdent are automatically imported.
// Explicitly importing a package with Import is generally only necessary
// when the import will be blank (import _ "package").
func (g *GeneratedFile) Import(importPath GoImportPath) {
	g.manualImports[importPath] = true
}

// Write implements io.Writer.
func (g *GeneratedFile) Write(p []byte) (n int, err error) {
	return g.buf.Write(p)
}

// Skip removes the generated file from the plugin output.
func (g *GeneratedFile) Skip() {
	g.skip = true
}

// Unskip reverts a previous call to Skip, re-including the generated file in
// the plugin output.
func (g *GeneratedFile) Unskip() {
	g.skip = false
}

// Annotate associates a symbol in a generated Go file with a location in a
// source .proto file.
//
// The symbol may refer to a type, constant, variable, function, method, or
// struct field.  The "T.sel" syntax is used to identify the method or field
// 'sel' on type 'T'.
//
// Deprecated: Use the AnnotateSymbol method instead.
func (g *GeneratedFile) Annotate(symbol string, loc Location) {
	g.AnnotateSymbol(symbol, Annotation{Location: loc})
}

// An Annotation provides semantic detail for a generated proto element.
//
// See the google.protobuf.GeneratedCodeInfo.Annotation documentation in
// descriptor.proto for details.
type Annotation struct {
	// Location is the source .proto file for the element.
	Location Location

	// Semantic is the symbol's effect on the element in the original .proto file.
	Semantic *descriptorpb.GeneratedCodeInfo_Annotation_Semantic
}

// AnnotateSymbol associates a symbol in a generated Go file with a location
// in a source .proto file and a semantic type.
//
// The symbol may refer to a type, constant, variable, function, method, or
// struct field.  The "T.sel" syntax is used to identify the method or field
// 'sel' on type 'T'.
func (g *GeneratedFile) AnnotateSymbol(symbol string, info Annotation) {
	g.annotations[symbol] = append(g.annotations[symbol], info)
}

// Content returns the contents of the generated file.
func (g *GeneratedFile) Content() ([]byte, error) {
	if !strings.HasSuffix(g.filename, ".go") {
		return g.buf.Bytes(), nil
	}

	// Reformat generated code.
	original := g.buf.Bytes()
	fset := token.NewFileSet()
	file, err := parser.ParseFile(fset, "", original, parser.ParseComments)
	if err != nil {
		// Print out the bad code with line numbers.
		// This should never happen in practice, but it can while changing generated code
		// so consider this a debugging aid.
		var src bytes.Buffer
		s := bufio.NewScanner(bytes.NewReader(original))
		for line := 1; s.Scan(); line++ {
			fmt.Fprintf(&src, "%5d\t%s\n", line, s.Bytes())
		}
		return nil, fmt.Errorf("%v: unparsable Go source: %v\n%v", g.filename, err, src.String())
	}

	// Collect a sorted list of all imports.
	var importPaths [][2]string
	rewriteImport := func(importPath string) string {
		if f := g.gen.opts.ImportRewriteFunc; f != nil {
			return string(f(GoImportPath(importPath)))
		}
		return importPath
	}
	for importPath := range g.packageNames {
		pkgName := string(g.packageNames[GoImportPath(importPath)])
		pkgPath := rewriteImport(string(importPath))
		importPaths = append(importPaths, [2]string{pkgName, pkgPath})
	}
	for importPath := range g.manualImports {
		if _, ok := g.packageNames[importPath]; !ok {
			pkgPath := rewriteImport(string(importPath))
			importPaths = append(importPaths, [2]string{"_", pkgPath})
		}
	}
	sort.Slice(importPaths, func(i, j int) bool {
		return importPaths[i][1] < importPaths[j][1]
	})

	// Modify the AST to include a new import block.
	if len(importPaths) > 0 {
		// Insert block after package statement or
		// possible comment attached to the end of the package statement.
		pos := file.Package
		tokFile := fset.File(file.Package)
		pkgLine := tokFile.Line(file.Package)
		for _, c := range file.Comments {
			if tokFile.Line(c.Pos()) > pkgLine {
				break
			}
			pos = c.End()
		}

		// Construct the import block.
		impDecl := &ast.GenDecl{
			Tok:    token.IMPORT,
			TokPos: pos,
			Lparen: pos,
			Rparen: pos,
		}
		for _, importPath := range importPaths {
			impDecl.Specs = append(impDecl.Specs, &ast.ImportSpec{
				Name: &ast.Ident{
					Name:    importPath[0],
					NamePos: pos,
				},
				Path: &ast.BasicLit{
					Kind:     token.STRING,
					Value:    strconv.Quote(importPath[1]),
					ValuePos: pos,
				},
				EndPos: pos,
			})
		}
		file.Decls = append([]ast.Decl{impDecl}, file.Decls...)
	}

	var out bytes.Buffer
	if err = (&printer.Config{Mode: printer.TabIndent | printer.UseSpaces, Tabwidth: 8}).Fprint(&out, fset, file); err != nil {
		return nil, fmt.Errorf("%v: can not reformat Go source: %v", g.filename, err)
	}
	return out.Bytes(), nil
}

func (g *GeneratedFile) generatedCodeInfo(content []byte) (*descriptorpb.GeneratedCodeInfo, error) {
	fset := token.NewFileSet()
	astFile, err := parser.ParseFile(fset, "", content, 0)
	if err != nil {
		return nil, err
	}
	info := &descriptorpb.GeneratedCodeInfo{}

	seenAnnotations := make(map[string]bool)
	annotate := func(s string, ident *ast.Ident) {
		seenAnnotations[s] = true
		for _, a := range g.annotations[s] {
			info.Annotation = append(info.Annotation, &descriptorpb.GeneratedCodeInfo_Annotation{
				SourceFile: proto.String(a.Location.SourceFile),
				Path:       a.Location.Path,
				Begin:      proto.Int32(int32(fset.Position(ident.Pos()).Offset)),
				End:        proto.Int32(int32(fset.Position(ident.End()).Offset)),
				Semantic:   a.Semantic,
			})
		}
	}
	for _, decl := range astFile.Decls {
		switch decl := decl.(type) {
		case *ast.GenDecl:
			for _, spec := range decl.Specs {
				switch spec := spec.(type) {
				case *ast.TypeSpec:
					annotate(spec.Name.Name, spec.Name)
					switch st := spec.Type.(type) {
					case *ast.StructType:
						for _, field := range st.Fields.List {
							for _, name := range field.Names {
								annotate(spec.Name.Name+"."+name.Name, name)
							}
						}
					case *ast.InterfaceType:
						for _, field := range st.Methods.List {
							for _, name := range field.Names {
								annotate(spec.Name.Name+"."+name.Name, name)
							}
						}
					}
				case *ast.ValueSpec:
					for _, name := range spec.Names {
						annotate(name.Name, name)
					}
				}
			}
		case *ast.FuncDecl:
			if decl.Recv == nil {
				annotate(decl.Name.Name, decl.Name)
			} else {
				recv := decl.Recv.List[0].Type
				if s, ok := recv.(*ast.StarExpr); ok {
					recv = s.X
				}
				if id, ok := recv.(*ast.Ident); ok {
					annotate(id.Name+"."+decl.Name.Name, decl.Name)
				}
			}
		}
	}
	for a := range g.annotations {
		if !seenAnnotations[a] {
			return nil, fmt.Errorf("%v: no symbol matching annotation %q", g.filename, a)
		}
	}

	return info, nil
}

// metaFile returns the contents of the file's metadata file, which is a
// text formatted string of the google.protobuf.GeneratedCodeInfo.
func (g *GeneratedFile) metaFile(content []byte) (string, error) {
	info, err := g.generatedCodeInfo(content)
	if err != nil {
		return "", err
	}

	b, err := prototext.Marshal(info)
	if err != nil {
		return "", err
	}
	return string(b), nil
}

// A GoIdent is a Go identifier, consisting of a name and import path.
// The name is a single identifier and may not be a dot-qualified selector.
type GoIdent struct {
	GoName       string
	GoImportPath GoImportPath
}

func (id GoIdent) String() string { return fmt.Sprintf("%q.%v", id.GoImportPath, id.GoName) }

// newGoIdent returns the Go identifier for a descriptor.
func newGoIdent(f *File, d protoreflect.Descriptor) GoIdent {
	name := strings.TrimPrefix(string(d.FullName()), string(f.Desc.Package())+".")
	return GoIdent{
		GoName:       strs.GoCamelCase(name),
		GoImportPath: f.GoImportPath,
	}
}

// A GoImportPath is the import path of a Go package.
// For example: "google.golang.org/protobuf/compiler/protogen"
type GoImportPath string

func (p GoImportPath) String() string { return strconv.Quote(string(p)) }

// Ident returns a GoIdent with s as the GoName and p as the GoImportPath.
func (p GoImportPath) Ident(s string) GoIdent {
	return GoIdent{GoName: s, GoImportPath: p}
}

// A GoPackageName is the name of a Go package. e.g., "protobuf".
type GoPackageName string

// cleanPackageName converts a string to a valid Go package name.
func cleanPackageName(name string) GoPackageName {
	return GoPackageName(strs.GoSanitized(name))
}

type pathType int

const (
	pathTypeImport pathType = iota
	pathTypeSourceRelative
)

// A Location is a location in a .proto source file.
//
// See the google.protobuf.SourceCodeInfo documentation in descriptor.proto
// for details.
type Location struct {
	SourceFile string
	Path       protoreflect.SourcePath
}

// appendPath add elements to a Location's path, returning a new Location.
func (loc Location) appendPath(num protoreflect.FieldNumber, idx int) Location {
	loc.Path = append(protoreflect.SourcePath(nil), loc.Path...) // make copy
	loc.Path = append(loc.Path, int32(num), int32(idx))
	return loc
}

// CommentSet is a set of leading and trailing comments associated
// with a .proto descriptor declaration.
type CommentSet struct {
	LeadingDetached []Comments
	Leading         Comments
	Trailing        Comments
}

func makeCommentSet(loc protoreflect.SourceLocation) CommentSet {
	var leadingDetached []Comments
	for _, s := range loc.LeadingDetachedComments {
		leadingDetached = append(leadingDetached, Comments(s))
	}
	return CommentSet{
		LeadingDetached: leadingDetached,
		Leading:         Comments(loc.LeadingComments),
		Trailing:        Comments(loc.TrailingComments),
	}
}

// Comments is a comments string as provided by protoc.
type Comments string

// String formats the comments by inserting // to the start of each line,
// ensuring that there is a trailing newline.
// An empty comment is formatted as an empty string.
func (c Comments) String() string {
	if c == "" {
		return ""
	}
	var b []byte
	for _, line := range strings.Split(strings.TrimSuffix(string(c), "\n"), "\n") {
		b = append(b, "//"...)
		b = append(b, line...)
		b = append(b, "\n"...)
	}
	return string(b)
}

// extensionRegistry allows registration of new extensions defined in the .proto
// file for which we are generating bindings.
//
// Lookups consult the local type registry first and fall back to the base type
// registry which defaults to protoregistry.GlobalTypes
type extensionRegistry struct {
	base  *protoregistry.Types
	local *protoregistry.Types
}

func newExtensionRegistry() *extensionRegistry {
	return &extensionRegistry{
		base:  protoregistry.GlobalTypes,
		local: &protoregistry.Types{},
	}
}

// FindExtensionByName implements proto.UnmarshalOptions.FindExtensionByName
func (e *extensionRegistry) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
	if xt, err := e.local.FindExtensionByName(field); err == nil {
		return xt, nil
	}

	return e.base.FindExtensionByName(field)
}

// FindExtensionByNumber implements proto.UnmarshalOptions.FindExtensionByNumber
func (e *extensionRegistry) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
	if xt, err := e.local.FindExtensionByNumber(message, field); err == nil {
		return xt, nil
	}

	return e.base.FindExtensionByNumber(message, field)
}

func (e *extensionRegistry) hasNovelExtensions() bool {
	return e.local.NumExtensions() > 0
}

func (e *extensionRegistry) registerAllExtensionsFromFile(f protoreflect.FileDescriptor) error {
	if err := e.registerAllExtensions(f.Extensions()); err != nil {
		return err
	}
	return nil
}

func (e *extensionRegistry) registerAllExtensionsFromMessage(ms protoreflect.MessageDescriptors) error {
	for i := 0; i < ms.Len(); i++ {
		m := ms.Get(i)
		if err := e.registerAllExtensions(m.Extensions()); err != nil {
			return err
		}
	}
	return nil
}

func (e *extensionRegistry) registerAllExtensions(exts protoreflect.ExtensionDescriptors) error {
	for i := 0; i < exts.Len(); i++ {
		if err := e.registerExtension(exts.Get(i)); err != nil {
			return err
		}
	}
	return nil
}

// registerExtension adds the given extension to the type registry if an
// extension with that full name does not exist yet.
func (e *extensionRegistry) registerExtension(xd protoreflect.ExtensionDescriptor) error {
	if _, err := e.FindExtensionByName(xd.FullName()); err != protoregistry.NotFound {
		// Either the extension already exists or there was an error, either way we're done.
		return err
	}
	return e.local.RegisterExtension(dynamicpb.NewExtensionType(xd))
}