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// 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 protoregistry provides data structures to register and lookup
// protobuf descriptor types.
//
// The Files registry contains file descriptors and provides the ability
// to iterate over the files or lookup a specific descriptor within the files.
// Files only contains protobuf descriptors and has no understanding of Go
// type information that may be associated with each descriptor.
//
// The Types registry contains descriptor types for which there is a known
// Go type associated with that descriptor. It provides the ability to iterate
// over the registered types or lookup a type by name.
package protoregistry
import (
"fmt"
"log"
"reflect"
"strings"
"sync"
"google.golang.org/protobuf/internal/errors"
"google.golang.org/protobuf/reflect/protoreflect"
)
// ignoreConflict reports whether to ignore a registration conflict
// given the descriptor being registered and the error.
// It is a variable so that the behavior is easily overridden in another file.
var ignoreConflict = func(d protoreflect.Descriptor, err error) bool {
log.Printf(""+
"WARNING: %v\n"+
"A future release will panic on registration conflicts.\n"+
// TODO: Add a URL pointing to documentation on how to resolve conflicts.
"\n", err)
return true
}
var globalMutex sync.RWMutex
// GlobalFiles is a global registry of file descriptors.
var GlobalFiles *Files = new(Files)
// GlobalTypes is the registry used by default for type lookups
// unless a local registry is provided by the user.
var GlobalTypes *Types = new(Types)
// NotFound is a sentinel error value to indicate that the type was not found.
var NotFound = errors.New("not found")
// Files is a registry for looking up or iterating over files and the
// descriptors contained within them.
// The Find and Range methods are safe for concurrent use.
type Files struct {
// The map of descsByName contains:
// EnumDescriptor
// EnumValueDescriptor
// MessageDescriptor
// ExtensionDescriptor
// ServiceDescriptor
// *packageDescriptor
//
// Note that files are stored as a slice, since a package may contain
// multiple files. Only top-level declarations are registered.
// Note that enum values are in the top-level since that are in the same
// scope as the parent enum.
descsByName map[protoreflect.FullName]interface{}
filesByPath map[string]protoreflect.FileDescriptor
}
type packageDescriptor struct {
files []protoreflect.FileDescriptor
}
// NewFiles returns a registry initialized with the provided set of files.
// Files with a namespace conflict with an pre-existing file are not registered.
func NewFiles(files ...protoreflect.FileDescriptor) *Files {
r := new(Files)
r.Register(files...) // ignore errors; first takes precedence
return r
}
// Register registers the provided list of file descriptors.
//
// If any descriptor within a file conflicts with the descriptor of any
// previously registered file (e.g., two enums with the same full name),
// then that file is not registered and an error is returned.
//
// It is permitted for multiple files to have the same file path.
func (r *Files) Register(files ...protoreflect.FileDescriptor) error {
if r == GlobalFiles {
globalMutex.Lock()
defer globalMutex.Unlock()
}
if r.descsByName == nil {
r.descsByName = map[protoreflect.FullName]interface{}{
"": &packageDescriptor{},
}
r.filesByPath = make(map[string]protoreflect.FileDescriptor)
}
var firstErr error
for _, file := range files {
if err := r.registerFile(file); err != nil && firstErr == nil {
firstErr = err
}
}
return firstErr
}
func (r *Files) registerFile(fd protoreflect.FileDescriptor) error {
path := fd.Path()
if prev := r.filesByPath[path]; prev != nil {
err := errors.New("file %q is already registered", fd.Path())
err = amendErrorWithCaller(err, prev, fd)
if r == GlobalFiles && ignoreConflict(fd, err) {
err = nil
}
return err
}
for name := fd.Package(); name != ""; name = name.Parent() {
switch prev := r.descsByName[name]; prev.(type) {
case nil, *packageDescriptor:
default:
err := errors.New("file %q has a package name conflict over %v", fd.Path(), name)
err = amendErrorWithCaller(err, prev, fd)
if r == GlobalFiles && ignoreConflict(fd, err) {
err = nil
}
return err
}
}
var err error
var hasConflict bool
rangeTopLevelDescriptors(fd, func(d protoreflect.Descriptor) {
if prev := r.descsByName[d.FullName()]; prev != nil {
hasConflict = true
err = errors.New("file %q has a name conflict over %v", fd.Path(), d.FullName())
err = amendErrorWithCaller(err, prev, fd)
if r == GlobalFiles && ignoreConflict(d, err) {
err = nil
}
}
})
if hasConflict {
return err
}
for name := fd.Package(); name != ""; name = name.Parent() {
if r.descsByName[name] == nil {
r.descsByName[name] = &packageDescriptor{}
}
}
p := r.descsByName[fd.Package()].(*packageDescriptor)
p.files = append(p.files, fd)
rangeTopLevelDescriptors(fd, func(d protoreflect.Descriptor) {
r.descsByName[d.FullName()] = d
})
r.filesByPath[path] = fd
return nil
}
// FindDescriptorByName looks up a descriptor by the full name.
//
// This returns (nil, NotFound) if not found.
func (r *Files) FindDescriptorByName(name protoreflect.FullName) (protoreflect.Descriptor, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
prefix := name
suffix := nameSuffix("")
for prefix != "" {
if d, ok := r.descsByName[prefix]; ok {
switch d := d.(type) {
case protoreflect.EnumDescriptor:
if d.FullName() == name {
return d, nil
}
case protoreflect.EnumValueDescriptor:
if d.FullName() == name {
return d, nil
}
case protoreflect.MessageDescriptor:
if d.FullName() == name {
return d, nil
}
if d := findDescriptorInMessage(d, suffix); d != nil && d.FullName() == name {
return d, nil
}
case protoreflect.ExtensionDescriptor:
if d.FullName() == name {
return d, nil
}
case protoreflect.ServiceDescriptor:
if d.FullName() == name {
return d, nil
}
if d := d.Methods().ByName(suffix.Pop()); d != nil && d.FullName() == name {
return d, nil
}
}
return nil, NotFound
}
prefix = prefix.Parent()
suffix = nameSuffix(name[len(prefix)+len("."):])
}
return nil, NotFound
}
func findDescriptorInMessage(md protoreflect.MessageDescriptor, suffix nameSuffix) protoreflect.Descriptor {
name := suffix.Pop()
if suffix == "" {
if ed := md.Enums().ByName(name); ed != nil {
return ed
}
for i := md.Enums().Len() - 1; i >= 0; i-- {
if vd := md.Enums().Get(i).Values().ByName(name); vd != nil {
return vd
}
}
if xd := md.Extensions().ByName(name); xd != nil {
return xd
}
if fd := md.Fields().ByName(name); fd != nil {
return fd
}
if od := md.Oneofs().ByName(name); od != nil {
return od
}
}
if md := md.Messages().ByName(name); md != nil {
if suffix == "" {
return md
}
return findDescriptorInMessage(md, suffix)
}
return nil
}
type nameSuffix string
func (s *nameSuffix) Pop() (name protoreflect.Name) {
if i := strings.IndexByte(string(*s), '.'); i >= 0 {
name, *s = protoreflect.Name((*s)[:i]), (*s)[i+1:]
} else {
name, *s = protoreflect.Name((*s)), ""
}
return name
}
// FindFileByPath looks up a file by the path.
//
// This returns (nil, NotFound) if not found.
func (r *Files) FindFileByPath(path string) (protoreflect.FileDescriptor, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
if fd, ok := r.filesByPath[path]; ok {
return fd, nil
}
return nil, NotFound
}
// NumFiles reports the number of registered files.
func (r *Files) NumFiles() int {
if r == nil {
return 0
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
return len(r.filesByPath)
}
// RangeFiles iterates over all registered files.
// The iteration order is undefined.
func (r *Files) RangeFiles(f func(protoreflect.FileDescriptor) bool) {
if r == nil {
return
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
for _, file := range r.filesByPath {
if !f(file) {
return
}
}
}
// NumFilesByPackage reports the number of registered files in a proto package.
func (r *Files) NumFilesByPackage(name protoreflect.FullName) int {
if r == nil {
return 0
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
p, ok := r.descsByName[name].(*packageDescriptor)
if !ok {
return 0
}
return len(p.files)
}
// RangeFilesByPackage iterates over all registered files in a give proto package.
// The iteration order is undefined.
func (r *Files) RangeFilesByPackage(name protoreflect.FullName, f func(protoreflect.FileDescriptor) bool) {
if r == nil {
return
}
if r == GlobalFiles {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
p, ok := r.descsByName[name].(*packageDescriptor)
if !ok {
return
}
for _, file := range p.files {
if !f(file) {
return
}
}
}
// rangeTopLevelDescriptors iterates over all top-level descriptors in a file
// which will be directly entered into the registry.
func rangeTopLevelDescriptors(fd protoreflect.FileDescriptor, f func(protoreflect.Descriptor)) {
eds := fd.Enums()
for i := eds.Len() - 1; i >= 0; i-- {
f(eds.Get(i))
vds := eds.Get(i).Values()
for i := vds.Len() - 1; i >= 0; i-- {
f(vds.Get(i))
}
}
mds := fd.Messages()
for i := mds.Len() - 1; i >= 0; i-- {
f(mds.Get(i))
}
xds := fd.Extensions()
for i := xds.Len() - 1; i >= 0; i-- {
f(xds.Get(i))
}
sds := fd.Services()
for i := sds.Len() - 1; i >= 0; i-- {
f(sds.Get(i))
}
}
// Type is an interface satisfied by protoreflect.EnumType,
// protoreflect.MessageType, or protoreflect.ExtensionType.
type Type interface {
GoType() reflect.Type
}
var (
_ Type = protoreflect.EnumType(nil)
_ Type = protoreflect.MessageType(nil)
_ Type = protoreflect.ExtensionType(nil)
)
// MessageTypeResolver is an interface for looking up messages.
//
// A compliant implementation must deterministically return the same type
// if no error is encountered.
//
// The Types type implements this interface.
type MessageTypeResolver interface {
// FindMessageByName looks up a message by its full name.
// E.g., "google.protobuf.Any"
//
// This return (nil, NotFound) if not found.
FindMessageByName(message protoreflect.FullName) (protoreflect.MessageType, error)
// FindMessageByURL looks up a message by a URL identifier.
// See documentation on google.protobuf.Any.type_url for the URL format.
//
// This returns (nil, NotFound) if not found.
FindMessageByURL(url string) (protoreflect.MessageType, error)
}
// ExtensionTypeResolver is an interface for looking up extensions.
//
// A compliant implementation must deterministically return the same type
// if no error is encountered.
//
// The Types type implements this interface.
type ExtensionTypeResolver interface {
// FindExtensionByName looks up a extension field by the field's full name.
// Note that this is the full name of the field as determined by
// where the extension is declared and is unrelated to the full name of the
// message being extended.
//
// This returns (nil, NotFound) if not found.
FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)
// FindExtensionByNumber looks up a extension field by the field number
// within some parent message, identified by full name.
//
// This returns (nil, NotFound) if not found.
FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)
}
var (
_ MessageTypeResolver = (*Types)(nil)
_ ExtensionTypeResolver = (*Types)(nil)
)
// Types is a registry for looking up or iterating over descriptor types.
// The Find and Range methods are safe for concurrent use.
type Types struct {
// TODO: The syntax of the URL is ill-defined and the protobuf team recently
// changed the documented semantics in a way that breaks prior usages.
// I do not believe they can do this and need to sync up with the
// protobuf team again to hash out what the proper syntax of the URL is.
// TODO: Should we separate this out as a registry for each type?
//
// In Java, the extension and message registry are distinct classes.
// Their extension registry has knowledge of distinct Java types,
// while their message registry only contains descriptor information.
//
// In Go, we have always registered messages, enums, and extensions.
// Messages and extensions are registered with Go information, while enums
// are only registered with descriptor information. We cannot drop Go type
// information for messages otherwise we would be unable to implement
// portions of the v1 API such as ptypes.DynamicAny.
//
// There is no enum registry in Java. In v1, we used the enum registry
// because enum types provided no reflective methods. The addition of
// ProtoReflect removes that need.
typesByName typesByName
extensionsByMessage extensionsByMessage
numEnums int
numMessages int
numExtensions int
}
type (
typesByName map[protoreflect.FullName]Type
extensionsByMessage map[protoreflect.FullName]extensionsByNumber
extensionsByNumber map[protoreflect.FieldNumber]protoreflect.ExtensionType
)
// NewTypes returns a registry initialized with the provided set of types.
// If there are conflicts, the first one takes precedence.
func NewTypes(typs ...Type) *Types {
r := new(Types)
r.Register(typs...) // ignore errors; first takes precedence
return r
}
// Register registers the provided list of descriptor types.
//
// If a registration conflict occurs for enum, message, or extension types
// (e.g., two different types have the same full name),
// then the first type takes precedence and an error is returned.
func (r *Types) Register(typs ...Type) error {
if r == GlobalTypes {
globalMutex.Lock()
defer globalMutex.Unlock()
}
var firstErr error
typeLoop:
for _, typ := range typs {
switch typ.(type) {
case protoreflect.EnumType, protoreflect.MessageType, protoreflect.ExtensionType:
// Check for conflicts in typesByName.
var desc protoreflect.Descriptor
var pcnt *int
switch t := typ.(type) {
case protoreflect.EnumType:
desc = t.Descriptor()
pcnt = &r.numEnums
case protoreflect.MessageType:
desc = t.Descriptor()
pcnt = &r.numMessages
case protoreflect.ExtensionType:
desc = t.TypeDescriptor()
pcnt = &r.numExtensions
default:
panic(fmt.Sprintf("invalid type: %T", t))
}
name := desc.FullName()
if prev := r.typesByName[name]; prev != nil {
err := errors.New("%v %v is already registered", typeName(typ), name)
err = amendErrorWithCaller(err, prev, typ)
if r == GlobalTypes && ignoreConflict(desc, err) {
err = nil
}
if firstErr == nil {
firstErr = err
}
continue typeLoop
}
// Check for conflicts in extensionsByMessage.
if xt, _ := typ.(protoreflect.ExtensionType); xt != nil {
xd := xt.TypeDescriptor()
field := xd.Number()
message := xd.ContainingMessage().FullName()
if prev := r.extensionsByMessage[message][field]; prev != nil {
err := errors.New("extension number %d is already registered on message %v", field, message)
err = amendErrorWithCaller(err, prev, typ)
if r == GlobalTypes && ignoreConflict(xd, err) {
err = nil
}
if firstErr == nil {
firstErr = err
}
continue typeLoop
}
// Update extensionsByMessage.
if r.extensionsByMessage == nil {
r.extensionsByMessage = make(extensionsByMessage)
}
if r.extensionsByMessage[message] == nil {
r.extensionsByMessage[message] = make(extensionsByNumber)
}
r.extensionsByMessage[message][field] = xt
}
// Update typesByName and the count.
if r.typesByName == nil {
r.typesByName = make(typesByName)
}
r.typesByName[name] = typ
(*pcnt)++
default:
if firstErr == nil {
firstErr = errors.New("invalid type: %v", typeName(typ))
}
}
}
return firstErr
}
// FindEnumByName looks up an enum by its full name.
// E.g., "google.protobuf.Field.Kind".
//
// This returns (nil, NotFound) if not found.
func (r *Types) FindEnumByName(enum protoreflect.FullName) (protoreflect.EnumType, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
if v := r.typesByName[enum]; v != nil {
if et, _ := v.(protoreflect.EnumType); et != nil {
return et, nil
}
return nil, errors.New("found wrong type: got %v, want enum", typeName(v))
}
return nil, NotFound
}
// FindMessageByName looks up a message by its full name.
// E.g., "google.protobuf.Any"
//
// This return (nil, NotFound) if not found.
func (r *Types) FindMessageByName(message protoreflect.FullName) (protoreflect.MessageType, error) {
// The full name by itself is a valid URL.
return r.FindMessageByURL(string(message))
}
// FindMessageByURL looks up a message by a URL identifier.
// See documentation on google.protobuf.Any.type_url for the URL format.
//
// This returns (nil, NotFound) if not found.
func (r *Types) FindMessageByURL(url string) (protoreflect.MessageType, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
message := protoreflect.FullName(url)
if i := strings.LastIndexByte(url, '/'); i >= 0 {
message = message[i+len("/"):]
}
if v := r.typesByName[message]; v != nil {
if mt, _ := v.(protoreflect.MessageType); mt != nil {
return mt, nil
}
return nil, errors.New("found wrong type: got %v, want message", typeName(v))
}
return nil, NotFound
}
// FindExtensionByName looks up a extension field by the field's full name.
// Note that this is the full name of the field as determined by
// where the extension is declared and is unrelated to the full name of the
// message being extended.
//
// This returns (nil, NotFound) if not found.
func (r *Types) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
if v := r.typesByName[field]; v != nil {
if xt, _ := v.(protoreflect.ExtensionType); xt != nil {
return xt, nil
}
return nil, errors.New("found wrong type: got %v, want extension", typeName(v))
}
return nil, NotFound
}
// FindExtensionByNumber looks up a extension field by the field number
// within some parent message, identified by full name.
//
// This returns (nil, NotFound) if not found.
func (r *Types) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
if r == nil {
return nil, NotFound
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
if xt, ok := r.extensionsByMessage[message][field]; ok {
return xt, nil
}
return nil, NotFound
}
// NumEnums reports the number of registered enums.
func (r *Types) NumEnums() int {
if r == nil {
return 0
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
return r.numEnums
}
// RangeEnums iterates over all registered enums.
// Iteration order is undefined.
func (r *Types) RangeEnums(f func(protoreflect.EnumType) bool) {
if r == nil {
return
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
for _, typ := range r.typesByName {
if et, ok := typ.(protoreflect.EnumType); ok {
if !f(et) {
return
}
}
}
}
// NumMessages reports the number of registered messages.
func (r *Types) NumMessages() int {
if r == nil {
return 0
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
return r.numMessages
}
// RangeMessages iterates over all registered messages.
// Iteration order is undefined.
func (r *Types) RangeMessages(f func(protoreflect.MessageType) bool) {
if r == nil {
return
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
for _, typ := range r.typesByName {
if mt, ok := typ.(protoreflect.MessageType); ok {
if !f(mt) {
return
}
}
}
}
// NumExtensions reports the number of registered extensions.
func (r *Types) NumExtensions() int {
if r == nil {
return 0
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
return r.numExtensions
}
// RangeExtensions iterates over all registered extensions.
// Iteration order is undefined.
func (r *Types) RangeExtensions(f func(protoreflect.ExtensionType) bool) {
if r == nil {
return
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
for _, typ := range r.typesByName {
if xt, ok := typ.(protoreflect.ExtensionType); ok {
if !f(xt) {
return
}
}
}
}
// NumExtensionsByMessage reports the number of registered extensions for
// a given message type.
func (r *Types) NumExtensionsByMessage(message protoreflect.FullName) int {
if r == nil {
return 0
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
return len(r.extensionsByMessage[message])
}
// RangeExtensionsByMessage iterates over all registered extensions filtered
// by a given message type. Iteration order is undefined.
func (r *Types) RangeExtensionsByMessage(message protoreflect.FullName, f func(protoreflect.ExtensionType) bool) {
if r == nil {
return
}
if r == GlobalTypes {
globalMutex.RLock()
defer globalMutex.RUnlock()
}
for _, xt := range r.extensionsByMessage[message] {
if !f(xt) {
return
}
}
}
func typeName(t Type) string {
switch t.(type) {
case protoreflect.EnumType:
return "enum"
case protoreflect.MessageType:
return "message"
case protoreflect.ExtensionType:
return "extension"
default:
return fmt.Sprintf("%T", t)
}
}
func amendErrorWithCaller(err error, prev, curr interface{}) error {
prevPkg := goPackage(prev)
currPkg := goPackage(curr)
if prevPkg == "" || currPkg == "" || prevPkg == currPkg {
return err
}
return errors.New("%s\n\tpreviously from: %q\n\tcurrently from: %q", err, prevPkg, currPkg)
}
func goPackage(v interface{}) string {
switch d := v.(type) {
case protoreflect.EnumType:
v = d.Descriptor()
case protoreflect.MessageType:
v = d.Descriptor()
case protoreflect.ExtensionType:
v = d.TypeDescriptor()
}
if d, ok := v.(protoreflect.Descriptor); ok {
v = d.ParentFile()
}
if d, ok := v.(interface{ GoPackagePath() string }); ok {
return d.GoPackagePath()
}
return ""
}