1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Package protoregistry provides data structures to register and lookup
6// protobuf descriptor types.
7//
8// The Files registry contains file descriptors and provides the ability
9// to iterate over the files or lookup a specific descriptor within the files.
10// Files only contains protobuf descriptors and has no understanding of Go
11// type information that may be associated with each descriptor.
12//
13// The Types registry contains descriptor types for which there is a known
14// Go type associated with that descriptor. It provides the ability to iterate
15// over the registered types or lookup a type by name.
16package protoregistry
17
18import (
19	"fmt"
20	"log"
21	"strings"
22	"sync"
23
24	"google.golang.org/protobuf/internal/encoding/messageset"
25	"google.golang.org/protobuf/internal/errors"
26	"google.golang.org/protobuf/internal/flags"
27	"google.golang.org/protobuf/reflect/protoreflect"
28)
29
30// ignoreConflict reports whether to ignore a registration conflict
31// given the descriptor being registered and the error.
32// It is a variable so that the behavior is easily overridden in another file.
33var ignoreConflict = func(d protoreflect.Descriptor, err error) bool {
34	log.Printf(""+
35		"WARNING: %v\n"+
36		"A future release will panic on registration conflicts. See:\n"+
37		"https://developers.google.com/protocol-buffers/docs/reference/go/faq#namespace-conflict\n"+
38		"\n", err)
39	return true
40}
41
42var globalMutex sync.RWMutex
43
44// GlobalFiles is a global registry of file descriptors.
45var GlobalFiles *Files = new(Files)
46
47// GlobalTypes is the registry used by default for type lookups
48// unless a local registry is provided by the user.
49var GlobalTypes *Types = new(Types)
50
51// NotFound is a sentinel error value to indicate that the type was not found.
52//
53// Since registry lookup can happen in the critical performance path, resolvers
54// must return this exact error value, not an error wrapping it.
55var NotFound = errors.New("not found")
56
57// Files is a registry for looking up or iterating over files and the
58// descriptors contained within them.
59// The Find and Range methods are safe for concurrent use.
60type Files struct {
61	// The map of descsByName contains:
62	//	EnumDescriptor
63	//	EnumValueDescriptor
64	//	MessageDescriptor
65	//	ExtensionDescriptor
66	//	ServiceDescriptor
67	//	*packageDescriptor
68	//
69	// Note that files are stored as a slice, since a package may contain
70	// multiple files. Only top-level declarations are registered.
71	// Note that enum values are in the top-level since that are in the same
72	// scope as the parent enum.
73	descsByName map[protoreflect.FullName]interface{}
74	filesByPath map[string]protoreflect.FileDescriptor
75}
76
77type packageDescriptor struct {
78	files []protoreflect.FileDescriptor
79}
80
81// RegisterFile registers the provided file descriptor.
82//
83// If any descriptor within the file conflicts with the descriptor of any
84// previously registered file (e.g., two enums with the same full name),
85// then the file is not registered and an error is returned.
86//
87// It is permitted for multiple files to have the same file path.
88func (r *Files) RegisterFile(file protoreflect.FileDescriptor) error {
89	if r == GlobalFiles {
90		globalMutex.Lock()
91		defer globalMutex.Unlock()
92	}
93	if r.descsByName == nil {
94		r.descsByName = map[protoreflect.FullName]interface{}{
95			"": &packageDescriptor{},
96		}
97		r.filesByPath = make(map[string]protoreflect.FileDescriptor)
98	}
99	path := file.Path()
100	if prev := r.filesByPath[path]; prev != nil {
101		// TODO: Remove this after some soak-in period after moving these types.
102		var prevPath string
103		const prevModule = "google.golang.org/genproto"
104		const prevVersion = "cb27e3aa (May 26th, 2020)"
105		switch path {
106		case "google/protobuf/field_mask.proto":
107			prevPath = prevModule + "/protobuf/field_mask"
108		case "google/protobuf/api.proto":
109			prevPath = prevModule + "/protobuf/api"
110		case "google/protobuf/type.proto":
111			prevPath = prevModule + "/protobuf/ptype"
112		case "google/protobuf/source_context.proto":
113			prevPath = prevModule + "/protobuf/source_context"
114		}
115		if r == GlobalFiles && prevPath != "" {
116			pkgName := strings.TrimSuffix(strings.TrimPrefix(path, "google/protobuf/"), ".proto")
117			pkgName = strings.Replace(pkgName, "_", "", -1) + "pb"
118			currPath := "google.golang.org/protobuf/types/known/" + pkgName
119			panic(fmt.Sprintf(""+
120				"duplicate registration of %q\n"+
121				"\n"+
122				"The generated definition for this file has moved:\n"+
123				"\tfrom: %q\n"+
124				"\tto:   %q\n"+
125				"A dependency on the %q module must\n"+
126				"be at version %v or higher.\n"+
127				"\n"+
128				"Upgrade the dependency by running:\n"+
129				"\tgo get -u %v\n",
130				path, prevPath, currPath, prevModule, prevVersion, prevPath))
131		}
132
133		err := errors.New("file %q is already registered", file.Path())
134		err = amendErrorWithCaller(err, prev, file)
135		if r == GlobalFiles && ignoreConflict(file, err) {
136			err = nil
137		}
138		return err
139	}
140
141	for name := file.Package(); name != ""; name = name.Parent() {
142		switch prev := r.descsByName[name]; prev.(type) {
143		case nil, *packageDescriptor:
144		default:
145			err := errors.New("file %q has a package name conflict over %v", file.Path(), name)
146			err = amendErrorWithCaller(err, prev, file)
147			if r == GlobalFiles && ignoreConflict(file, err) {
148				err = nil
149			}
150			return err
151		}
152	}
153	var err error
154	var hasConflict bool
155	rangeTopLevelDescriptors(file, func(d protoreflect.Descriptor) {
156		if prev := r.descsByName[d.FullName()]; prev != nil {
157			hasConflict = true
158			err = errors.New("file %q has a name conflict over %v", file.Path(), d.FullName())
159			err = amendErrorWithCaller(err, prev, file)
160			if r == GlobalFiles && ignoreConflict(d, err) {
161				err = nil
162			}
163		}
164	})
165	if hasConflict {
166		return err
167	}
168
169	for name := file.Package(); name != ""; name = name.Parent() {
170		if r.descsByName[name] == nil {
171			r.descsByName[name] = &packageDescriptor{}
172		}
173	}
174	p := r.descsByName[file.Package()].(*packageDescriptor)
175	p.files = append(p.files, file)
176	rangeTopLevelDescriptors(file, func(d protoreflect.Descriptor) {
177		r.descsByName[d.FullName()] = d
178	})
179	r.filesByPath[path] = file
180	return nil
181}
182
183// FindDescriptorByName looks up a descriptor by the full name.
184//
185// This returns (nil, NotFound) if not found.
186func (r *Files) FindDescriptorByName(name protoreflect.FullName) (protoreflect.Descriptor, error) {
187	if r == nil {
188		return nil, NotFound
189	}
190	if r == GlobalFiles {
191		globalMutex.RLock()
192		defer globalMutex.RUnlock()
193	}
194	prefix := name
195	suffix := nameSuffix("")
196	for prefix != "" {
197		if d, ok := r.descsByName[prefix]; ok {
198			switch d := d.(type) {
199			case protoreflect.EnumDescriptor:
200				if d.FullName() == name {
201					return d, nil
202				}
203			case protoreflect.EnumValueDescriptor:
204				if d.FullName() == name {
205					return d, nil
206				}
207			case protoreflect.MessageDescriptor:
208				if d.FullName() == name {
209					return d, nil
210				}
211				if d := findDescriptorInMessage(d, suffix); d != nil && d.FullName() == name {
212					return d, nil
213				}
214			case protoreflect.ExtensionDescriptor:
215				if d.FullName() == name {
216					return d, nil
217				}
218			case protoreflect.ServiceDescriptor:
219				if d.FullName() == name {
220					return d, nil
221				}
222				if d := d.Methods().ByName(suffix.Pop()); d != nil && d.FullName() == name {
223					return d, nil
224				}
225			}
226			return nil, NotFound
227		}
228		prefix = prefix.Parent()
229		suffix = nameSuffix(name[len(prefix)+len("."):])
230	}
231	return nil, NotFound
232}
233
234func findDescriptorInMessage(md protoreflect.MessageDescriptor, suffix nameSuffix) protoreflect.Descriptor {
235	name := suffix.Pop()
236	if suffix == "" {
237		if ed := md.Enums().ByName(name); ed != nil {
238			return ed
239		}
240		for i := md.Enums().Len() - 1; i >= 0; i-- {
241			if vd := md.Enums().Get(i).Values().ByName(name); vd != nil {
242				return vd
243			}
244		}
245		if xd := md.Extensions().ByName(name); xd != nil {
246			return xd
247		}
248		if fd := md.Fields().ByName(name); fd != nil {
249			return fd
250		}
251		if od := md.Oneofs().ByName(name); od != nil {
252			return od
253		}
254	}
255	if md := md.Messages().ByName(name); md != nil {
256		if suffix == "" {
257			return md
258		}
259		return findDescriptorInMessage(md, suffix)
260	}
261	return nil
262}
263
264type nameSuffix string
265
266func (s *nameSuffix) Pop() (name protoreflect.Name) {
267	if i := strings.IndexByte(string(*s), '.'); i >= 0 {
268		name, *s = protoreflect.Name((*s)[:i]), (*s)[i+1:]
269	} else {
270		name, *s = protoreflect.Name((*s)), ""
271	}
272	return name
273}
274
275// FindFileByPath looks up a file by the path.
276//
277// This returns (nil, NotFound) if not found.
278func (r *Files) FindFileByPath(path string) (protoreflect.FileDescriptor, error) {
279	if r == nil {
280		return nil, NotFound
281	}
282	if r == GlobalFiles {
283		globalMutex.RLock()
284		defer globalMutex.RUnlock()
285	}
286	if fd, ok := r.filesByPath[path]; ok {
287		return fd, nil
288	}
289	return nil, NotFound
290}
291
292// NumFiles reports the number of registered files.
293func (r *Files) NumFiles() int {
294	if r == nil {
295		return 0
296	}
297	if r == GlobalFiles {
298		globalMutex.RLock()
299		defer globalMutex.RUnlock()
300	}
301	return len(r.filesByPath)
302}
303
304// RangeFiles iterates over all registered files while f returns true.
305// The iteration order is undefined.
306func (r *Files) RangeFiles(f func(protoreflect.FileDescriptor) bool) {
307	if r == nil {
308		return
309	}
310	if r == GlobalFiles {
311		globalMutex.RLock()
312		defer globalMutex.RUnlock()
313	}
314	for _, file := range r.filesByPath {
315		if !f(file) {
316			return
317		}
318	}
319}
320
321// NumFilesByPackage reports the number of registered files in a proto package.
322func (r *Files) NumFilesByPackage(name protoreflect.FullName) int {
323	if r == nil {
324		return 0
325	}
326	if r == GlobalFiles {
327		globalMutex.RLock()
328		defer globalMutex.RUnlock()
329	}
330	p, ok := r.descsByName[name].(*packageDescriptor)
331	if !ok {
332		return 0
333	}
334	return len(p.files)
335}
336
337// RangeFilesByPackage iterates over all registered files in a given proto package
338// while f returns true. The iteration order is undefined.
339func (r *Files) RangeFilesByPackage(name protoreflect.FullName, f func(protoreflect.FileDescriptor) bool) {
340	if r == nil {
341		return
342	}
343	if r == GlobalFiles {
344		globalMutex.RLock()
345		defer globalMutex.RUnlock()
346	}
347	p, ok := r.descsByName[name].(*packageDescriptor)
348	if !ok {
349		return
350	}
351	for _, file := range p.files {
352		if !f(file) {
353			return
354		}
355	}
356}
357
358// rangeTopLevelDescriptors iterates over all top-level descriptors in a file
359// which will be directly entered into the registry.
360func rangeTopLevelDescriptors(fd protoreflect.FileDescriptor, f func(protoreflect.Descriptor)) {
361	eds := fd.Enums()
362	for i := eds.Len() - 1; i >= 0; i-- {
363		f(eds.Get(i))
364		vds := eds.Get(i).Values()
365		for i := vds.Len() - 1; i >= 0; i-- {
366			f(vds.Get(i))
367		}
368	}
369	mds := fd.Messages()
370	for i := mds.Len() - 1; i >= 0; i-- {
371		f(mds.Get(i))
372	}
373	xds := fd.Extensions()
374	for i := xds.Len() - 1; i >= 0; i-- {
375		f(xds.Get(i))
376	}
377	sds := fd.Services()
378	for i := sds.Len() - 1; i >= 0; i-- {
379		f(sds.Get(i))
380	}
381}
382
383// MessageTypeResolver is an interface for looking up messages.
384//
385// A compliant implementation must deterministically return the same type
386// if no error is encountered.
387//
388// The Types type implements this interface.
389type MessageTypeResolver interface {
390	// FindMessageByName looks up a message by its full name.
391	// E.g., "google.protobuf.Any"
392	//
393	// This return (nil, NotFound) if not found.
394	FindMessageByName(message protoreflect.FullName) (protoreflect.MessageType, error)
395
396	// FindMessageByURL looks up a message by a URL identifier.
397	// See documentation on google.protobuf.Any.type_url for the URL format.
398	//
399	// This returns (nil, NotFound) if not found.
400	FindMessageByURL(url string) (protoreflect.MessageType, error)
401}
402
403// ExtensionTypeResolver is an interface for looking up extensions.
404//
405// A compliant implementation must deterministically return the same type
406// if no error is encountered.
407//
408// The Types type implements this interface.
409type ExtensionTypeResolver interface {
410	// FindExtensionByName looks up a extension field by the field's full name.
411	// Note that this is the full name of the field as determined by
412	// where the extension is declared and is unrelated to the full name of the
413	// message being extended.
414	//
415	// This returns (nil, NotFound) if not found.
416	FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)
417
418	// FindExtensionByNumber looks up a extension field by the field number
419	// within some parent message, identified by full name.
420	//
421	// This returns (nil, NotFound) if not found.
422	FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)
423}
424
425var (
426	_ MessageTypeResolver   = (*Types)(nil)
427	_ ExtensionTypeResolver = (*Types)(nil)
428)
429
430// Types is a registry for looking up or iterating over descriptor types.
431// The Find and Range methods are safe for concurrent use.
432type Types struct {
433	typesByName         typesByName
434	extensionsByMessage extensionsByMessage
435
436	numEnums      int
437	numMessages   int
438	numExtensions int
439}
440
441type (
442	typesByName         map[protoreflect.FullName]interface{}
443	extensionsByMessage map[protoreflect.FullName]extensionsByNumber
444	extensionsByNumber  map[protoreflect.FieldNumber]protoreflect.ExtensionType
445)
446
447// RegisterMessage registers the provided message type.
448//
449// If a naming conflict occurs, the type is not registered and an error is returned.
450func (r *Types) RegisterMessage(mt protoreflect.MessageType) error {
451	// Under rare circumstances getting the descriptor might recursively
452	// examine the registry, so fetch it before locking.
453	md := mt.Descriptor()
454
455	if r == GlobalTypes {
456		globalMutex.Lock()
457		defer globalMutex.Unlock()
458	}
459
460	if err := r.register("message", md, mt); err != nil {
461		return err
462	}
463	r.numMessages++
464	return nil
465}
466
467// RegisterEnum registers the provided enum type.
468//
469// If a naming conflict occurs, the type is not registered and an error is returned.
470func (r *Types) RegisterEnum(et protoreflect.EnumType) error {
471	// Under rare circumstances getting the descriptor might recursively
472	// examine the registry, so fetch it before locking.
473	ed := et.Descriptor()
474
475	if r == GlobalTypes {
476		globalMutex.Lock()
477		defer globalMutex.Unlock()
478	}
479
480	if err := r.register("enum", ed, et); err != nil {
481		return err
482	}
483	r.numEnums++
484	return nil
485}
486
487// RegisterExtension registers the provided extension type.
488//
489// If a naming conflict occurs, the type is not registered and an error is returned.
490func (r *Types) RegisterExtension(xt protoreflect.ExtensionType) error {
491	// Under rare circumstances getting the descriptor might recursively
492	// examine the registry, so fetch it before locking.
493	//
494	// A known case where this can happen: Fetching the TypeDescriptor for a
495	// legacy ExtensionDesc can consult the global registry.
496	xd := xt.TypeDescriptor()
497
498	if r == GlobalTypes {
499		globalMutex.Lock()
500		defer globalMutex.Unlock()
501	}
502
503	field := xd.Number()
504	message := xd.ContainingMessage().FullName()
505	if prev := r.extensionsByMessage[message][field]; prev != nil {
506		err := errors.New("extension number %d is already registered on message %v", field, message)
507		err = amendErrorWithCaller(err, prev, xt)
508		if !(r == GlobalTypes && ignoreConflict(xd, err)) {
509			return err
510		}
511	}
512
513	if err := r.register("extension", xd, xt); err != nil {
514		return err
515	}
516	if r.extensionsByMessage == nil {
517		r.extensionsByMessage = make(extensionsByMessage)
518	}
519	if r.extensionsByMessage[message] == nil {
520		r.extensionsByMessage[message] = make(extensionsByNumber)
521	}
522	r.extensionsByMessage[message][field] = xt
523	r.numExtensions++
524	return nil
525}
526
527func (r *Types) register(kind string, desc protoreflect.Descriptor, typ interface{}) error {
528	name := desc.FullName()
529	prev := r.typesByName[name]
530	if prev != nil {
531		err := errors.New("%v %v is already registered", kind, name)
532		err = amendErrorWithCaller(err, prev, typ)
533		if !(r == GlobalTypes && ignoreConflict(desc, err)) {
534			return err
535		}
536	}
537	if r.typesByName == nil {
538		r.typesByName = make(typesByName)
539	}
540	r.typesByName[name] = typ
541	return nil
542}
543
544// FindEnumByName looks up an enum by its full name.
545// E.g., "google.protobuf.Field.Kind".
546//
547// This returns (nil, NotFound) if not found.
548func (r *Types) FindEnumByName(enum protoreflect.FullName) (protoreflect.EnumType, error) {
549	if r == nil {
550		return nil, NotFound
551	}
552	if r == GlobalTypes {
553		globalMutex.RLock()
554		defer globalMutex.RUnlock()
555	}
556	if v := r.typesByName[enum]; v != nil {
557		if et, _ := v.(protoreflect.EnumType); et != nil {
558			return et, nil
559		}
560		return nil, errors.New("found wrong type: got %v, want enum", typeName(v))
561	}
562	return nil, NotFound
563}
564
565// FindMessageByName looks up a message by its full name,
566// e.g. "google.protobuf.Any".
567//
568// This returns (nil, NotFound) if not found.
569func (r *Types) FindMessageByName(message protoreflect.FullName) (protoreflect.MessageType, error) {
570	if r == nil {
571		return nil, NotFound
572	}
573	if r == GlobalTypes {
574		globalMutex.RLock()
575		defer globalMutex.RUnlock()
576	}
577	if v := r.typesByName[message]; v != nil {
578		if mt, _ := v.(protoreflect.MessageType); mt != nil {
579			return mt, nil
580		}
581		return nil, errors.New("found wrong type: got %v, want message", typeName(v))
582	}
583	return nil, NotFound
584}
585
586// FindMessageByURL looks up a message by a URL identifier.
587// See documentation on google.protobuf.Any.type_url for the URL format.
588//
589// This returns (nil, NotFound) if not found.
590func (r *Types) FindMessageByURL(url string) (protoreflect.MessageType, error) {
591	// This function is similar to FindMessageByName but
592	// truncates anything before and including '/' in the URL.
593	if r == nil {
594		return nil, NotFound
595	}
596	if r == GlobalTypes {
597		globalMutex.RLock()
598		defer globalMutex.RUnlock()
599	}
600	message := protoreflect.FullName(url)
601	if i := strings.LastIndexByte(url, '/'); i >= 0 {
602		message = message[i+len("/"):]
603	}
604
605	if v := r.typesByName[message]; v != nil {
606		if mt, _ := v.(protoreflect.MessageType); mt != nil {
607			return mt, nil
608		}
609		return nil, errors.New("found wrong type: got %v, want message", typeName(v))
610	}
611	return nil, NotFound
612}
613
614// FindExtensionByName looks up a extension field by the field's full name.
615// Note that this is the full name of the field as determined by
616// where the extension is declared and is unrelated to the full name of the
617// message being extended.
618//
619// This returns (nil, NotFound) if not found.
620func (r *Types) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
621	if r == nil {
622		return nil, NotFound
623	}
624	if r == GlobalTypes {
625		globalMutex.RLock()
626		defer globalMutex.RUnlock()
627	}
628	if v := r.typesByName[field]; v != nil {
629		if xt, _ := v.(protoreflect.ExtensionType); xt != nil {
630			return xt, nil
631		}
632
633		// MessageSet extensions are special in that the name of the extension
634		// is the name of the message type used to extend the MessageSet.
635		// This naming scheme is used by text and JSON serialization.
636		//
637		// This feature is protected by the ProtoLegacy flag since MessageSets
638		// are a proto1 feature that is long deprecated.
639		if flags.ProtoLegacy {
640			if _, ok := v.(protoreflect.MessageType); ok {
641				field := field.Append(messageset.ExtensionName)
642				if v := r.typesByName[field]; v != nil {
643					if xt, _ := v.(protoreflect.ExtensionType); xt != nil {
644						if messageset.IsMessageSetExtension(xt.TypeDescriptor()) {
645							return xt, nil
646						}
647					}
648				}
649			}
650		}
651
652		return nil, errors.New("found wrong type: got %v, want extension", typeName(v))
653	}
654	return nil, NotFound
655}
656
657// FindExtensionByNumber looks up a extension field by the field number
658// within some parent message, identified by full name.
659//
660// This returns (nil, NotFound) if not found.
661func (r *Types) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
662	if r == nil {
663		return nil, NotFound
664	}
665	if r == GlobalTypes {
666		globalMutex.RLock()
667		defer globalMutex.RUnlock()
668	}
669	if xt, ok := r.extensionsByMessage[message][field]; ok {
670		return xt, nil
671	}
672	return nil, NotFound
673}
674
675// NumEnums reports the number of registered enums.
676func (r *Types) NumEnums() int {
677	if r == nil {
678		return 0
679	}
680	if r == GlobalTypes {
681		globalMutex.RLock()
682		defer globalMutex.RUnlock()
683	}
684	return r.numEnums
685}
686
687// RangeEnums iterates over all registered enums while f returns true.
688// Iteration order is undefined.
689func (r *Types) RangeEnums(f func(protoreflect.EnumType) bool) {
690	if r == nil {
691		return
692	}
693	if r == GlobalTypes {
694		globalMutex.RLock()
695		defer globalMutex.RUnlock()
696	}
697	for _, typ := range r.typesByName {
698		if et, ok := typ.(protoreflect.EnumType); ok {
699			if !f(et) {
700				return
701			}
702		}
703	}
704}
705
706// NumMessages reports the number of registered messages.
707func (r *Types) NumMessages() int {
708	if r == nil {
709		return 0
710	}
711	if r == GlobalTypes {
712		globalMutex.RLock()
713		defer globalMutex.RUnlock()
714	}
715	return r.numMessages
716}
717
718// RangeMessages iterates over all registered messages while f returns true.
719// Iteration order is undefined.
720func (r *Types) RangeMessages(f func(protoreflect.MessageType) bool) {
721	if r == nil {
722		return
723	}
724	if r == GlobalTypes {
725		globalMutex.RLock()
726		defer globalMutex.RUnlock()
727	}
728	for _, typ := range r.typesByName {
729		if mt, ok := typ.(protoreflect.MessageType); ok {
730			if !f(mt) {
731				return
732			}
733		}
734	}
735}
736
737// NumExtensions reports the number of registered extensions.
738func (r *Types) NumExtensions() int {
739	if r == nil {
740		return 0
741	}
742	if r == GlobalTypes {
743		globalMutex.RLock()
744		defer globalMutex.RUnlock()
745	}
746	return r.numExtensions
747}
748
749// RangeExtensions iterates over all registered extensions while f returns true.
750// Iteration order is undefined.
751func (r *Types) RangeExtensions(f func(protoreflect.ExtensionType) bool) {
752	if r == nil {
753		return
754	}
755	if r == GlobalTypes {
756		globalMutex.RLock()
757		defer globalMutex.RUnlock()
758	}
759	for _, typ := range r.typesByName {
760		if xt, ok := typ.(protoreflect.ExtensionType); ok {
761			if !f(xt) {
762				return
763			}
764		}
765	}
766}
767
768// NumExtensionsByMessage reports the number of registered extensions for
769// a given message type.
770func (r *Types) NumExtensionsByMessage(message protoreflect.FullName) int {
771	if r == nil {
772		return 0
773	}
774	if r == GlobalTypes {
775		globalMutex.RLock()
776		defer globalMutex.RUnlock()
777	}
778	return len(r.extensionsByMessage[message])
779}
780
781// RangeExtensionsByMessage iterates over all registered extensions filtered
782// by a given message type while f returns true. Iteration order is undefined.
783func (r *Types) RangeExtensionsByMessage(message protoreflect.FullName, f func(protoreflect.ExtensionType) bool) {
784	if r == nil {
785		return
786	}
787	if r == GlobalTypes {
788		globalMutex.RLock()
789		defer globalMutex.RUnlock()
790	}
791	for _, xt := range r.extensionsByMessage[message] {
792		if !f(xt) {
793			return
794		}
795	}
796}
797
798func typeName(t interface{}) string {
799	switch t.(type) {
800	case protoreflect.EnumType:
801		return "enum"
802	case protoreflect.MessageType:
803		return "message"
804	case protoreflect.ExtensionType:
805		return "extension"
806	default:
807		return fmt.Sprintf("%T", t)
808	}
809}
810
811func amendErrorWithCaller(err error, prev, curr interface{}) error {
812	prevPkg := goPackage(prev)
813	currPkg := goPackage(curr)
814	if prevPkg == "" || currPkg == "" || prevPkg == currPkg {
815		return err
816	}
817	return errors.New("%s\n\tpreviously from: %q\n\tcurrently from:  %q", err, prevPkg, currPkg)
818}
819
820func goPackage(v interface{}) string {
821	switch d := v.(type) {
822	case protoreflect.EnumType:
823		v = d.Descriptor()
824	case protoreflect.MessageType:
825		v = d.Descriptor()
826	case protoreflect.ExtensionType:
827		v = d.TypeDescriptor()
828	}
829	if d, ok := v.(protoreflect.Descriptor); ok {
830		v = d.ParentFile()
831	}
832	if d, ok := v.(interface{ GoPackagePath() string }); ok {
833		return d.GoPackagePath()
834	}
835	return ""
836}
837