internal/impl/legacy_enum.go - protobuf - Git at Google

 // 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 impl

 import (
 	"fmt"
 	"reflect"
 	"strings"
 	"sync"

 	"google.golang.org/protobuf/internal/filedesc"
 	"google.golang.org/protobuf/internal/strs"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 )

 // legacyEnumName returns the name of enums used in legacy code.
 // It is neither the protobuf full name nor the qualified Go name,
 // but rather an odd hybrid of both.
 func legacyEnumName(ed pref.EnumDescriptor) string {
 	var protoPkg string
 	enumName := string(ed.FullName())
 	if fd := ed.ParentFile(); fd != nil {
 		protoPkg = string(fd.Package())
 		enumName = strings.TrimPrefix(enumName, protoPkg+".")
 	}
 	if protoPkg == "" {
 		return strs.GoCamelCase(enumName)
 	}
 	return protoPkg + "." + strs.GoCamelCase(enumName)
 }

 // legacyWrapEnum wraps v as a protoreflect.Enum,
 // where v must be a int32 kind and not implement the v2 API already.
 func legacyWrapEnum(v reflect.Value) pref.Enum {
 	et := legacyLoadEnumType(v.Type())
 	return et.New(pref.EnumNumber(v.Int()))
 }

 var legacyEnumTypeCache sync.Map // map[reflect.Type]protoreflect.EnumType

 // legacyLoadEnumType dynamically loads a protoreflect.EnumType for t,
 // where t must be an int32 kind and not implement the v2 API already.
 func legacyLoadEnumType(t reflect.Type) pref.EnumType {
 	// Fast-path: check if a EnumType is cached for this concrete type.
 	if et, ok := legacyEnumTypeCache.Load(t); ok {
 		return et.(pref.EnumType)
 	}

 	// Slow-path: derive enum descriptor and initialize EnumType.
 	var et pref.EnumType
 	ed := LegacyLoadEnumDesc(t)
 	et = &legacyEnumType{
 		desc:   ed,
 		goType: t,
 	}
 	if et, ok := legacyEnumTypeCache.LoadOrStore(t, et); ok {
 		return et.(pref.EnumType)
 	}
 	return et
 }

 type legacyEnumType struct {
 	desc   pref.EnumDescriptor
 	goType reflect.Type
 	m      sync.Map // map[protoreflect.EnumNumber]proto.Enum
 }

 func (t *legacyEnumType) New(n pref.EnumNumber) pref.Enum {
 	if e, ok := t.m.Load(n); ok {
 		return e.(pref.Enum)
 	}
 	e := &legacyEnumWrapper{num: n, pbTyp: t, goTyp: t.goType}
 	t.m.Store(n, e)
 	return e
 }
 func (t *legacyEnumType) Descriptor() pref.EnumDescriptor {
 	return t.desc
 }

 type legacyEnumWrapper struct {
 	num   pref.EnumNumber
 	pbTyp pref.EnumType
 	goTyp reflect.Type
 }

 func (e *legacyEnumWrapper) Descriptor() pref.EnumDescriptor {
 	return e.pbTyp.Descriptor()
 }
 func (e *legacyEnumWrapper) Type() pref.EnumType {
 	return e.pbTyp
 }
 func (e *legacyEnumWrapper) Number() pref.EnumNumber {
 	return e.num
 }
 func (e *legacyEnumWrapper) ProtoReflect() pref.Enum {
 	return e
 }
 func (e *legacyEnumWrapper) protoUnwrap() interface{} {
 	v := reflect.New(e.goTyp).Elem()
 	v.SetInt(int64(e.num))
 	return v.Interface()
 }

 var (
 	_ pref.Enum = (*legacyEnumWrapper)(nil)
 	_ unwrapper = (*legacyEnumWrapper)(nil)
 )

 var legacyEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor

 // LegacyLoadEnumDesc returns an EnumDescriptor derived from the Go type,
 // which must be an int32 kind and not implement the v2 API already.
 //
 // This is exported for testing purposes.
 func LegacyLoadEnumDesc(t reflect.Type) pref.EnumDescriptor {
 	// Fast-path: check if an EnumDescriptor is cached for this concrete type.
 	if ed, ok := legacyEnumDescCache.Load(t); ok {
 		return ed.(pref.EnumDescriptor)
 	}

 	// Slow-path: initialize EnumDescriptor from the raw descriptor.
 	ev := reflect.Zero(t).Interface()
 	if _, ok := ev.(pref.Enum); ok {
 		panic(fmt.Sprintf("%v already implements proto.Enum", t))
 	}
 	edV1, ok := ev.(enumV1)
 	if !ok {
 		return aberrantLoadEnumDesc(t)
 	}
 	b, idxs := edV1.EnumDescriptor()

 	var ed pref.EnumDescriptor
 	if len(idxs) == 1 {
 		ed = legacyLoadFileDesc(b).Enums().Get(idxs[0])
 	} else {
 		md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
 		for _, i := range idxs[1 : len(idxs)-1] {
 			md = md.Messages().Get(i)
 		}
 		ed = md.Enums().Get(idxs[len(idxs)-1])
 	}
 	if ed, ok := legacyEnumDescCache.LoadOrStore(t, ed); ok {
 		return ed.(protoreflect.EnumDescriptor)
 	}
 	return ed
 }

 var aberrantEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor

 // aberrantLoadEnumDesc returns an EnumDescriptor derived from the Go type,
 // which must not implement protoreflect.Enum or enumV1.
 //
 // If the type does not implement enumV1, then there is no reliable
 // way to derive the original protobuf type information.
 // We are unable to use the global enum registry since it is
 // unfortunately keyed by the protobuf full name, which we also do not know.
 // Thus, this produces some bogus enum descriptor based on the Go type name.
 func aberrantLoadEnumDesc(t reflect.Type) pref.EnumDescriptor {
 	// Fast-path: check if an EnumDescriptor is cached for this concrete type.
 	if ed, ok := aberrantEnumDescCache.Load(t); ok {
 		return ed.(pref.EnumDescriptor)
 	}

 	// Slow-path: construct a bogus, but unique EnumDescriptor.
 	ed := &filedesc.Enum{L2: new(filedesc.EnumL2)}
 	ed.L0.FullName = AberrantDeriveFullName(t) // e.g., github_com.user.repo.MyEnum
 	ed.L0.ParentFile = filedesc.SurrogateProto3
 	ed.L2.Values.List = append(ed.L2.Values.List, filedesc.EnumValue{})

 	// TODO: Use the presence of a UnmarshalJSON method to determine proto2?

 	vd := &ed.L2.Values.List[0]
 	vd.L0.FullName = ed.L0.FullName + "_UNKNOWN" // e.g., github_com.user.repo.MyEnum_UNKNOWN
 	vd.L0.ParentFile = ed.L0.ParentFile
 	vd.L0.Parent = ed

 	// TODO: We could use the String method to obtain some enum value names by
 	// starting at 0 and print the enum until it produces invalid identifiers.
 	// An exhaustive query is clearly impractical, but can be best-effort.

 	if ed, ok := aberrantEnumDescCache.LoadOrStore(t, ed); ok {
 		return ed.(pref.EnumDescriptor)
 	}
 	return ed
 }

 // AberrantDeriveFullName derives a fully qualified protobuf name for the given Go type
 // The provided name is not guaranteed to be stable nor universally unique.
 // It should be sufficiently unique within a program.
 //
 // This is exported for testing purposes.
 func AberrantDeriveFullName(t reflect.Type) pref.FullName {
 	sanitize := func(r rune) rune {
 		switch {
 		case r == '/':
 			return '.'
 		case 'a' <= r && r <= 'z', 'A' <= r && r <= 'Z', '0' <= r && r <= '9':
 			return r
 		default:
 			return '_'
 		}
 	}
 	prefix := strings.Map(sanitize, t.PkgPath())
 	suffix := strings.Map(sanitize, t.Name())
 	if suffix == "" {
 		suffix = fmt.Sprintf("UnknownX%X", reflect.ValueOf(t).Pointer())
 	}

 	ss := append(strings.Split(prefix, "."), suffix)
 	for i, s := range ss {
 		if s == "" || ('0' <= s[0] && s[0] <= '9') {
 			ss[i] = "x" + s
 		}
 	}
 	return pref.FullName(strings.Join(ss, "."))
 }
	// 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 impl

	import (
	"fmt"
	"reflect"
	"strings"
	"sync"

	"google.golang.org/protobuf/internal/filedesc"
	"google.golang.org/protobuf/internal/strs"
	"google.golang.org/protobuf/reflect/protoreflect"
	pref "google.golang.org/protobuf/reflect/protoreflect"
	)

	// legacyEnumName returns the name of enums used in legacy code.
	// It is neither the protobuf full name nor the qualified Go name,
	// but rather an odd hybrid of both.
	func legacyEnumName(ed pref.EnumDescriptor) string {
	var protoPkg string
	enumName := string(ed.FullName())
	if fd := ed.ParentFile(); fd != nil {
	protoPkg = string(fd.Package())
	enumName = strings.TrimPrefix(enumName, protoPkg+".")
	}
	if protoPkg == "" {
	return strs.GoCamelCase(enumName)
	}
	return protoPkg + "." + strs.GoCamelCase(enumName)
	}

	// legacyWrapEnum wraps v as a protoreflect.Enum,
	// where v must be a int32 kind and not implement the v2 API already.
	func legacyWrapEnum(v reflect.Value) pref.Enum {
	et := legacyLoadEnumType(v.Type())
	return et.New(pref.EnumNumber(v.Int()))
	}

	var legacyEnumTypeCache sync.Map // map[reflect.Type]protoreflect.EnumType

	// legacyLoadEnumType dynamically loads a protoreflect.EnumType for t,
	// where t must be an int32 kind and not implement the v2 API already.
	func legacyLoadEnumType(t reflect.Type) pref.EnumType {
	// Fast-path: check if a EnumType is cached for this concrete type.
	if et, ok := legacyEnumTypeCache.Load(t); ok {
	return et.(pref.EnumType)
	}

	// Slow-path: derive enum descriptor and initialize EnumType.
	var et pref.EnumType
	ed := LegacyLoadEnumDesc(t)
	et = &legacyEnumType{
	desc: ed,
	goType: t,
	}
	if et, ok := legacyEnumTypeCache.LoadOrStore(t, et); ok {
	return et.(pref.EnumType)
	}
	return et
	}

	type legacyEnumType struct {
	desc pref.EnumDescriptor
	goType reflect.Type
	m sync.Map // map[protoreflect.EnumNumber]proto.Enum
	}

	func (t *legacyEnumType) New(n pref.EnumNumber) pref.Enum {
	if e, ok := t.m.Load(n); ok {
	return e.(pref.Enum)
	}
	e := &legacyEnumWrapper{num: n, pbTyp: t, goTyp: t.goType}
	t.m.Store(n, e)
	return e
	}
	func (t *legacyEnumType) Descriptor() pref.EnumDescriptor {
	return t.desc
	}

	type legacyEnumWrapper struct {
	num pref.EnumNumber
	pbTyp pref.EnumType
	goTyp reflect.Type
	}

	func (e *legacyEnumWrapper) Descriptor() pref.EnumDescriptor {
	return e.pbTyp.Descriptor()
	}
	func (e *legacyEnumWrapper) Type() pref.EnumType {
	return e.pbTyp
	}
	func (e *legacyEnumWrapper) Number() pref.EnumNumber {
	return e.num
	}
	func (e *legacyEnumWrapper) ProtoReflect() pref.Enum {
	return e
	}
	func (e *legacyEnumWrapper) protoUnwrap() interface{} {
	v := reflect.New(e.goTyp).Elem()
	v.SetInt(int64(e.num))
	return v.Interface()
	}

	var (
	_ pref.Enum = (*legacyEnumWrapper)(nil)
	_ unwrapper = (*legacyEnumWrapper)(nil)
	)

	var legacyEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor

	// LegacyLoadEnumDesc returns an EnumDescriptor derived from the Go type,
	// which must be an int32 kind and not implement the v2 API already.
	//
	// This is exported for testing purposes.
	func LegacyLoadEnumDesc(t reflect.Type) pref.EnumDescriptor {
	// Fast-path: check if an EnumDescriptor is cached for this concrete type.
	if ed, ok := legacyEnumDescCache.Load(t); ok {
	return ed.(pref.EnumDescriptor)
	}

	// Slow-path: initialize EnumDescriptor from the raw descriptor.
	ev := reflect.Zero(t).Interface()
	if _, ok := ev.(pref.Enum); ok {
	panic(fmt.Sprintf("%v already implements proto.Enum", t))
	}
	edV1, ok := ev.(enumV1)
	if !ok {
	return aberrantLoadEnumDesc(t)
	}
	b, idxs := edV1.EnumDescriptor()

	var ed pref.EnumDescriptor
	if len(idxs) == 1 {
	ed = legacyLoadFileDesc(b).Enums().Get(idxs[0])
	} else {
	md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
	for _, i := range idxs[1 : len(idxs)-1] {
	md = md.Messages().Get(i)
	}
	ed = md.Enums().Get(idxs[len(idxs)-1])
	}
	if ed, ok := legacyEnumDescCache.LoadOrStore(t, ed); ok {
	return ed.(protoreflect.EnumDescriptor)
	}
	return ed
	}

	var aberrantEnumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor

	// aberrantLoadEnumDesc returns an EnumDescriptor derived from the Go type,
	// which must not implement protoreflect.Enum or enumV1.
	//
	// If the type does not implement enumV1, then there is no reliable
	// way to derive the original protobuf type information.
	// We are unable to use the global enum registry since it is
	// unfortunately keyed by the protobuf full name, which we also do not know.
	// Thus, this produces some bogus enum descriptor based on the Go type name.
	func aberrantLoadEnumDesc(t reflect.Type) pref.EnumDescriptor {
	// Fast-path: check if an EnumDescriptor is cached for this concrete type.
	if ed, ok := aberrantEnumDescCache.Load(t); ok {
	return ed.(pref.EnumDescriptor)
	}

	// Slow-path: construct a bogus, but unique EnumDescriptor.
	ed := &filedesc.Enum{L2: new(filedesc.EnumL2)}
	ed.L0.FullName = AberrantDeriveFullName(t) // e.g., github_com.user.repo.MyEnum
	ed.L0.ParentFile = filedesc.SurrogateProto3
	ed.L2.Values.List = append(ed.L2.Values.List, filedesc.EnumValue{})

	// TODO: Use the presence of a UnmarshalJSON method to determine proto2?

	vd := &ed.L2.Values.List[0]
	vd.L0.FullName = ed.L0.FullName + "_UNKNOWN" // e.g., github_com.user.repo.MyEnum_UNKNOWN
	vd.L0.ParentFile = ed.L0.ParentFile
	vd.L0.Parent = ed

	// TODO: We could use the String method to obtain some enum value names by
	// starting at 0 and print the enum until it produces invalid identifiers.
	// An exhaustive query is clearly impractical, but can be best-effort.

	if ed, ok := aberrantEnumDescCache.LoadOrStore(t, ed); ok {
	return ed.(pref.EnumDescriptor)
	}
	return ed
	}

	// AberrantDeriveFullName derives a fully qualified protobuf name for the given Go type
	// The provided name is not guaranteed to be stable nor universally unique.
	// It should be sufficiently unique within a program.
	//
	// This is exported for testing purposes.
	func AberrantDeriveFullName(t reflect.Type) pref.FullName {
	sanitize := func(r rune) rune {
	switch {
	case r == '/':
	return '.'
	case 'a' <= r && r <= 'z', 'A' <= r && r <= 'Z', '0' <= r && r <= '9':
	return r
	default:
	return '_'
	}
	}
	prefix := strings.Map(sanitize, t.PkgPath())
	suffix := strings.Map(sanitize, t.Name())
	if suffix == "" {
	suffix = fmt.Sprintf("UnknownX%X", reflect.ValueOf(t).Pointer())
	}

	ss := append(strings.Split(prefix, "."), suffix)
	for i, s := range ss {
	if s == "" \|\| ('0' <= s[0] && s[0] <= '9') {
	ss[i] = "x" + s
	}
	}
	return pref.FullName(strings.Join(ss, "."))
	}