reflect/protoreflect/proto.go - protobuf.git - 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 protoreflect provides interfaces to dynamically manipulate messages.
 //
 // This package includes type descriptors which describe the structure of types
 // defined in proto source files and value interfaces which provide the
 // ability to examine and manipulate the contents of messages.
 //
 // # Protocol Buffer Descriptors
 //
 // Protobuf descriptors (e.g., [EnumDescriptor] or [MessageDescriptor])
 // are immutable objects that represent protobuf type information.
 // They are wrappers around the messages declared in descriptor.proto.
 // Protobuf descriptors alone lack any information regarding Go types.
 //
 // Enums and messages generated by this module implement [Enum] and [ProtoMessage],
 // where the Descriptor and ProtoReflect.Descriptor accessors respectively
 // return the protobuf descriptor for the values.
 //
 // The protobuf descriptor interfaces are not meant to be implemented by
 // user code since they might need to be extended in the future to support
 // additions to the protobuf language.
 // The [google.golang.org/protobuf/reflect/protodesc] package converts between
 // google.protobuf.DescriptorProto messages and protobuf descriptors.
 //
 // # Go Type Descriptors
 //
 // A type descriptor (e.g., [EnumType] or [MessageType]) is a constructor for
 // a concrete Go type that represents the associated protobuf descriptor.
 // There is commonly a one-to-one relationship between protobuf descriptors and
 // Go type descriptors, but it can potentially be a one-to-many relationship.
 //
 // Enums and messages generated by this module implement [Enum] and [ProtoMessage],
 // where the Type and ProtoReflect.Type accessors respectively
 // return the protobuf descriptor for the values.
 //
 // The [google.golang.org/protobuf/types/dynamicpb] package can be used to
 // create Go type descriptors from protobuf descriptors.
 //
 // # Value Interfaces
 //
 // The [Enum] and [Message] interfaces provide a reflective view over an
 // enum or message instance. For enums, it provides the ability to retrieve
 // the enum value number for any concrete enum type. For messages, it provides
 // the ability to access or manipulate fields of the message.
 //
 // To convert a [google.golang.org/protobuf/proto.Message] to a [protoreflect.Message], use the
 // former's ProtoReflect method. Since the ProtoReflect method is new to the
 // v2 message interface, it may not be present on older message implementations.
 // The [github.com/golang/protobuf/proto.MessageReflect] function can be used
 // to obtain a reflective view on older messages.
 //
 // # Relationships
 //
 // The following diagrams demonstrate the relationships between
 // various types declared in this package.
 //
 //	                       ┌───────────────────────────────────┐
 //	                       V                                   │
 //	   ┌────────────── New(n) ─────────────┐                   │
 //	   │                                   │                   │
 //	   │      ┌──── Descriptor() ──┐       │  ┌── Number() ──┐ │
 //	   │      │                    V       V  │              V │
 //	╔════════════╗  ╔════════════════╗  ╔════════╗  ╔════════════╗
 //	║  EnumType  ║  ║ EnumDescriptor ║  ║  Enum  ║  ║ EnumNumber ║
 //	╚════════════╝  ╚════════════════╝  ╚════════╝  ╚════════════╝
 //	      Λ           Λ                   │ │
 //	      │           └─── Descriptor() ──┘ │
 //	      │                                 │
 //	      └────────────────── Type() ───────┘
 //
 // • An [EnumType] describes a concrete Go enum type.
 // It has an EnumDescriptor and can construct an Enum instance.
 //
 // • An [EnumDescriptor] describes an abstract protobuf enum type.
 //
 // • An [Enum] is a concrete enum instance. Generated enums implement Enum.
 //
 //	  ┌──────────────── New() ─────────────────┐
 //	  │                                        │
 //	  │         ┌─── Descriptor() ─────┐       │   ┌── Interface() ───┐
 //	  │         │                      V       V   │                  V
 //	╔═════════════╗  ╔═══════════════════╗  ╔═════════╗  ╔══════════════╗
 //	║ MessageType ║  ║ MessageDescriptor ║  ║ Message ║  ║ ProtoMessage ║
 //	╚═════════════╝  ╚═══════════════════╝  ╚═════════╝  ╚══════════════╝
 //	       Λ           Λ                      │ │  Λ                  │
 //	       │           └──── Descriptor() ────┘ │  └─ ProtoReflect() ─┘
 //	       │                                    │
 //	       └─────────────────── Type() ─────────┘
 //
 // • A [MessageType] describes a concrete Go message type.
 // It has a [MessageDescriptor] and can construct a [Message] instance.
 // Just as how Go's [reflect.Type] is a reflective description of a Go type,
 // a [MessageType] is a reflective description of a Go type for a protobuf message.
 //
 // • A [MessageDescriptor] describes an abstract protobuf message type.
 // It has no understanding of Go types. In order to construct a [MessageType]
 // from just a [MessageDescriptor], you can consider looking up the message type
 // in the global registry using the FindMessageByName method on
 // [google.golang.org/protobuf/reflect/protoregistry.GlobalTypes]
 // or constructing a dynamic [MessageType] using
 // [google.golang.org/protobuf/types/dynamicpb.NewMessageType].
 //
 // • A [Message] is a reflective view over a concrete message instance.
 // Generated messages implement [ProtoMessage], which can convert to a [Message].
 // Just as how Go's [reflect.Value] is a reflective view over a Go value,
 // a [Message] is a reflective view over a concrete protobuf message instance.
 // Using Go reflection as an analogy, the [ProtoMessage.ProtoReflect] method is similar to
 // calling [reflect.ValueOf], and the [Message.Interface] method is similar to
 // calling [reflect.Value.Interface].
 //
 //	      ┌── TypeDescriptor() ──┐    ┌───── Descriptor() ─────┐
 //	      │                      V    │                        V
 //	╔═══════════════╗  ╔═════════════════════════╗  ╔═════════════════════╗
 //	║ ExtensionType ║  ║ ExtensionTypeDescriptor ║  ║ ExtensionDescriptor ║
 //	╚═══════════════╝  ╚═════════════════════════╝  ╚═════════════════════╝
 //	      Λ                      │   │ Λ                      │ Λ
 //	      └─────── Type() ───────┘   │ └─── may implement ────┘ │
 //	                                 │                          │
 //	                                 └────── implements ────────┘
 //
 // • An [ExtensionType] describes a concrete Go implementation of an extension.
 // It has an [ExtensionTypeDescriptor] and can convert to/from
 // an abstract [Value] and a Go value.
 //
 // • An [ExtensionTypeDescriptor] is an [ExtensionDescriptor]
 // which also has an [ExtensionType].
 //
 // • An [ExtensionDescriptor] describes an abstract protobuf extension field and
 // may not always be an [ExtensionTypeDescriptor].
 package protoreflect

 import (
 	"fmt"
 	"strings"

 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/internal/pragma"
 )

 type doNotImplement pragma.DoNotImplement

 // ProtoMessage is the top-level interface that all proto messages implement.
 // This is declared in the protoreflect package to avoid a cyclic dependency;
 // use the [google.golang.org/protobuf/proto.Message] type instead, which aliases this type.
 type ProtoMessage interface{ ProtoReflect() Message }

 // Syntax is the language version of the proto file.
 type Syntax syntax

 type syntax int8 // keep exact type opaque as the int type may change

 const (
 	Proto2   Syntax = 2
 	Proto3   Syntax = 3
 	Editions Syntax = 4
 )

 // IsValid reports whether the syntax is valid.
 func (s Syntax) IsValid() bool {
 	switch s {
 	case Proto2, Proto3, Editions:
 		return true
 	default:
 		return false
 	}
 }

 // String returns s as a proto source identifier (e.g., "proto2").
 func (s Syntax) String() string {
 	switch s {
 	case Proto2:
 		return "proto2"
 	case Proto3:
 		return "proto3"
 	case Editions:
 		return "editions"
 	default:
 		return fmt.Sprintf("<unknown:%d>", s)
 	}
 }

 // GoString returns s as a Go source identifier (e.g., "Proto2").
 func (s Syntax) GoString() string {
 	switch s {
 	case Proto2:
 		return "Proto2"
 	case Proto3:
 		return "Proto3"
 	default:
 		return fmt.Sprintf("Syntax(%d)", s)
 	}
 }

 // Cardinality determines whether a field is optional, required, or repeated.
 type Cardinality cardinality

 type cardinality int8 // keep exact type opaque as the int type may change

 // Constants as defined by the google.protobuf.Cardinality enumeration.
 const (
 	Optional Cardinality = 1 // appears zero or one times
 	Required Cardinality = 2 // appears exactly one time; invalid with Proto3
 	Repeated Cardinality = 3 // appears zero or more times
 )

 // IsValid reports whether the cardinality is valid.
 func (c Cardinality) IsValid() bool {
 	switch c {
 	case Optional, Required, Repeated:
 		return true
 	default:
 		return false
 	}
 }

 // String returns c as a proto source identifier (e.g., "optional").
 func (c Cardinality) String() string {
 	switch c {
 	case Optional:
 		return "optional"
 	case Required:
 		return "required"
 	case Repeated:
 		return "repeated"
 	default:
 		return fmt.Sprintf("<unknown:%d>", c)
 	}
 }

 // GoString returns c as a Go source identifier (e.g., "Optional").
 func (c Cardinality) GoString() string {
 	switch c {
 	case Optional:
 		return "Optional"
 	case Required:
 		return "Required"
 	case Repeated:
 		return "Repeated"
 	default:
 		return fmt.Sprintf("Cardinality(%d)", c)
 	}
 }

 // Kind indicates the basic proto kind of a field.
 type Kind kind

 type kind int8 // keep exact type opaque as the int type may change

 // Constants as defined by the google.protobuf.Field.Kind enumeration.
 const (
 	BoolKind     Kind = 8
 	EnumKind     Kind = 14
 	Int32Kind    Kind = 5
 	Sint32Kind   Kind = 17
 	Uint32Kind   Kind = 13
 	Int64Kind    Kind = 3
 	Sint64Kind   Kind = 18
 	Uint64Kind   Kind = 4
 	Sfixed32Kind Kind = 15
 	Fixed32Kind  Kind = 7
 	FloatKind    Kind = 2
 	Sfixed64Kind Kind = 16
 	Fixed64Kind  Kind = 6
 	DoubleKind   Kind = 1
 	StringKind   Kind = 9
 	BytesKind    Kind = 12
 	MessageKind  Kind = 11
 	GroupKind    Kind = 10
 )

 // IsValid reports whether the kind is valid.
 func (k Kind) IsValid() bool {
 	switch k {
 	case BoolKind, EnumKind,
 		Int32Kind, Sint32Kind, Uint32Kind,
 		Int64Kind, Sint64Kind, Uint64Kind,
 		Sfixed32Kind, Fixed32Kind, FloatKind,
 		Sfixed64Kind, Fixed64Kind, DoubleKind,
 		StringKind, BytesKind, MessageKind, GroupKind:
 		return true
 	default:
 		return false
 	}
 }

 // String returns k as a proto source identifier (e.g., "bool").
 func (k Kind) String() string {
 	switch k {
 	case BoolKind:
 		return "bool"
 	case EnumKind:
 		return "enum"
 	case Int32Kind:
 		return "int32"
 	case Sint32Kind:
 		return "sint32"
 	case Uint32Kind:
 		return "uint32"
 	case Int64Kind:
 		return "int64"
 	case Sint64Kind:
 		return "sint64"
 	case Uint64Kind:
 		return "uint64"
 	case Sfixed32Kind:
 		return "sfixed32"
 	case Fixed32Kind:
 		return "fixed32"
 	case FloatKind:
 		return "float"
 	case Sfixed64Kind:
 		return "sfixed64"
 	case Fixed64Kind:
 		return "fixed64"
 	case DoubleKind:
 		return "double"
 	case StringKind:
 		return "string"
 	case BytesKind:
 		return "bytes"
 	case MessageKind:
 		return "message"
 	case GroupKind:
 		return "group"
 	default:
 		return fmt.Sprintf("<unknown:%d>", k)
 	}
 }

 // GoString returns k as a Go source identifier (e.g., "BoolKind").
 func (k Kind) GoString() string {
 	switch k {
 	case BoolKind:
 		return "BoolKind"
 	case EnumKind:
 		return "EnumKind"
 	case Int32Kind:
 		return "Int32Kind"
 	case Sint32Kind:
 		return "Sint32Kind"
 	case Uint32Kind:
 		return "Uint32Kind"
 	case Int64Kind:
 		return "Int64Kind"
 	case Sint64Kind:
 		return "Sint64Kind"
 	case Uint64Kind:
 		return "Uint64Kind"
 	case Sfixed32Kind:
 		return "Sfixed32Kind"
 	case Fixed32Kind:
 		return "Fixed32Kind"
 	case FloatKind:
 		return "FloatKind"
 	case Sfixed64Kind:
 		return "Sfixed64Kind"
 	case Fixed64Kind:
 		return "Fixed64Kind"
 	case DoubleKind:
 		return "DoubleKind"
 	case StringKind:
 		return "StringKind"
 	case BytesKind:
 		return "BytesKind"
 	case MessageKind:
 		return "MessageKind"
 	case GroupKind:
 		return "GroupKind"
 	default:
 		return fmt.Sprintf("Kind(%d)", k)
 	}
 }

 // FieldNumber is the field number in a message.
 type FieldNumber = protowire.Number

 // FieldNumbers represent a list of field numbers.
 type FieldNumbers interface {
 	// Len reports the number of fields in the list.
 	Len() int
 	// Get returns the ith field number. It panics if out of bounds.
 	Get(i int) FieldNumber
 	// Has reports whether n is within the list of fields.
 	Has(n FieldNumber) bool

 	doNotImplement
 }

 // FieldRanges represent a list of field number ranges.
 type FieldRanges interface {
 	// Len reports the number of ranges in the list.
 	Len() int
 	// Get returns the ith range. It panics if out of bounds.
 	Get(i int) [2]FieldNumber // start inclusive; end exclusive
 	// Has reports whether n is within any of the ranges.
 	Has(n FieldNumber) bool

 	doNotImplement
 }

 // EnumNumber is the numeric value for an enum.
 type EnumNumber int32

 // EnumRanges represent a list of enum number ranges.
 type EnumRanges interface {
 	// Len reports the number of ranges in the list.
 	Len() int
 	// Get returns the ith range. It panics if out of bounds.
 	Get(i int) [2]EnumNumber // start inclusive; end inclusive
 	// Has reports whether n is within any of the ranges.
 	Has(n EnumNumber) bool

 	doNotImplement
 }

 // Name is the short name for a proto declaration. This is not the name
 // as used in Go source code, which might not be identical to the proto name.
 type Name string // e.g., "Kind"

 // IsValid reports whether s is a syntactically valid name.
 // An empty name is invalid.
 func (s Name) IsValid() bool {
 	return consumeIdent(string(s)) == len(s)
 }

 // Names represent a list of names.
 type Names interface {
 	// Len reports the number of names in the list.
 	Len() int
 	// Get returns the ith name. It panics if out of bounds.
 	Get(i int) Name
 	// Has reports whether s matches any names in the list.
 	Has(s Name) bool

 	doNotImplement
 }

 // FullName is a qualified name that uniquely identifies a proto declaration.
 // A qualified name is the concatenation of the proto package along with the
 // fully-declared name (i.e., name of parent preceding the name of the child),
 // with a '.' delimiter placed between each [Name].
 //
 // This should not have any leading or trailing dots.
 type FullName string // e.g., "google.protobuf.Field.Kind"

 // IsValid reports whether s is a syntactically valid full name.
 // An empty full name is invalid.
 func (s FullName) IsValid() bool {
 	i := consumeIdent(string(s))
 	if i < 0 {
 		return false
 	}
 	for len(s) > i {
 		if s[i] != '.' {
 			return false
 		}
 		i++
 		n := consumeIdent(string(s[i:]))
 		if n < 0 {
 			return false
 		}
 		i += n
 	}
 	return true
 }

 func consumeIdent(s string) (i int) {
 	if len(s) == 0 || !isLetter(s[i]) {
 		return -1
 	}
 	i++
 	for len(s) > i && isLetterDigit(s[i]) {
 		i++
 	}
 	return i
 }
 func isLetter(c byte) bool {
 	return c == '_' || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z')
 }
 func isLetterDigit(c byte) bool {
 	return isLetter(c) || ('0' <= c && c <= '9')
 }

 // Name returns the short name, which is the last identifier segment.
 // A single segment FullName is the [Name] itself.
 func (n FullName) Name() Name {
 	if i := strings.LastIndexByte(string(n), '.'); i >= 0 {
 		return Name(n[i+1:])
 	}
 	return Name(n)
 }

 // Parent returns the full name with the trailing identifier removed.
 // A single segment FullName has no parent.
 func (n FullName) Parent() FullName {
 	if i := strings.LastIndexByte(string(n), '.'); i >= 0 {
 		return n[:i]
 	}
 	return ""
 }

 // Append returns the qualified name appended with the provided short name.
 //
 // Invariant: n == n.Parent().Append(n.Name()) // assuming n is valid
 func (n FullName) Append(s Name) FullName {
 	if n == "" {
 		return FullName(s)
 	}
 	return n + "." + FullName(s)
 }
	// 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 protoreflect provides interfaces to dynamically manipulate messages.
	//
	// This package includes type descriptors which describe the structure of types
	// defined in proto source files and value interfaces which provide the
	// ability to examine and manipulate the contents of messages.
	//
	// # Protocol Buffer Descriptors
	//
	// Protobuf descriptors (e.g., [EnumDescriptor] or [MessageDescriptor])
	// are immutable objects that represent protobuf type information.
	// They are wrappers around the messages declared in descriptor.proto.
	// Protobuf descriptors alone lack any information regarding Go types.
	//
	// Enums and messages generated by this module implement [Enum] and [ProtoMessage],
	// where the Descriptor and ProtoReflect.Descriptor accessors respectively
	// return the protobuf descriptor for the values.
	//
	// The protobuf descriptor interfaces are not meant to be implemented by
	// user code since they might need to be extended in the future to support
	// additions to the protobuf language.
	// The [google.golang.org/protobuf/reflect/protodesc] package converts between
	// google.protobuf.DescriptorProto messages and protobuf descriptors.
	//
	// # Go Type Descriptors
	//
	// A type descriptor (e.g., [EnumType] or [MessageType]) is a constructor for
	// a concrete Go type that represents the associated protobuf descriptor.
	// There is commonly a one-to-one relationship between protobuf descriptors and
	// Go type descriptors, but it can potentially be a one-to-many relationship.
	//
	// Enums and messages generated by this module implement [Enum] and [ProtoMessage],
	// where the Type and ProtoReflect.Type accessors respectively
	// return the protobuf descriptor for the values.
	//
	// The [google.golang.org/protobuf/types/dynamicpb] package can be used to
	// create Go type descriptors from protobuf descriptors.
	//
	// # Value Interfaces
	//
	// The [Enum] and [Message] interfaces provide a reflective view over an
	// enum or message instance. For enums, it provides the ability to retrieve
	// the enum value number for any concrete enum type. For messages, it provides
	// the ability to access or manipulate fields of the message.
	//
	// To convert a [google.golang.org/protobuf/proto.Message] to a [protoreflect.Message], use the
	// former's ProtoReflect method. Since the ProtoReflect method is new to the
	// v2 message interface, it may not be present on older message implementations.
	// The [github.com/golang/protobuf/proto.MessageReflect] function can be used
	// to obtain a reflective view on older messages.
	//
	// # Relationships
	//
	// The following diagrams demonstrate the relationships between
	// various types declared in this package.
	//
	// ┌───────────────────────────────────┐
	// V │
	// ┌────────────── New(n) ─────────────┐ │
	// │ │ │
	// │ ┌──── Descriptor() ──┐ │ ┌── Number() ──┐ │
	// │ │ V V │ V │
	// ╔════════════╗ ╔════════════════╗ ╔════════╗ ╔════════════╗
	// ║ EnumType ║ ║ EnumDescriptor ║ ║ Enum ║ ║ EnumNumber ║
	// ╚════════════╝ ╚════════════════╝ ╚════════╝ ╚════════════╝
	// Λ Λ │ │
	// │ └─── Descriptor() ──┘ │
	// │ │
	// └────────────────── Type() ───────┘
	//
	// • An [EnumType] describes a concrete Go enum type.
	// It has an EnumDescriptor and can construct an Enum instance.
	//
	// • An [EnumDescriptor] describes an abstract protobuf enum type.
	//
	// • An [Enum] is a concrete enum instance. Generated enums implement Enum.
	//
	// ┌──────────────── New() ─────────────────┐
	// │ │
	// │ ┌─── Descriptor() ─────┐ │ ┌── Interface() ───┐
	// │ │ V V │ V
	// ╔═════════════╗ ╔═══════════════════╗ ╔═════════╗ ╔══════════════╗
	// ║ MessageType ║ ║ MessageDescriptor ║ ║ Message ║ ║ ProtoMessage ║
	// ╚═════════════╝ ╚═══════════════════╝ ╚═════════╝ ╚══════════════╝
	// Λ Λ │ │ Λ │
	// │ └──── Descriptor() ────┘ │ └─ ProtoReflect() ─┘
	// │ │
	// └─────────────────── Type() ─────────┘
	//
	// • A [MessageType] describes a concrete Go message type.
	// It has a [MessageDescriptor] and can construct a [Message] instance.
	// Just as how Go's [reflect.Type] is a reflective description of a Go type,
	// a [MessageType] is a reflective description of a Go type for a protobuf message.
	//
	// • A [MessageDescriptor] describes an abstract protobuf message type.
	// It has no understanding of Go types. In order to construct a [MessageType]
	// from just a [MessageDescriptor], you can consider looking up the message type
	// in the global registry using the FindMessageByName method on
	// [google.golang.org/protobuf/reflect/protoregistry.GlobalTypes]
	// or constructing a dynamic [MessageType] using
	// [google.golang.org/protobuf/types/dynamicpb.NewMessageType].
	//
	// • A [Message] is a reflective view over a concrete message instance.
	// Generated messages implement [ProtoMessage], which can convert to a [Message].
	// Just as how Go's [reflect.Value] is a reflective view over a Go value,
	// a [Message] is a reflective view over a concrete protobuf message instance.
	// Using Go reflection as an analogy, the [ProtoMessage.ProtoReflect] method is similar to
	// calling [reflect.ValueOf], and the [Message.Interface] method is similar to
	// calling [reflect.Value.Interface].
	//
	// ┌── TypeDescriptor() ──┐ ┌───── Descriptor() ─────┐
	// │ V │ V
	// ╔═══════════════╗ ╔═════════════════════════╗ ╔═════════════════════╗
	// ║ ExtensionType ║ ║ ExtensionTypeDescriptor ║ ║ ExtensionDescriptor ║
	// ╚═══════════════╝ ╚═════════════════════════╝ ╚═════════════════════╝
	// Λ │ │ Λ │ Λ
	// └─────── Type() ───────┘ │ └─── may implement ────┘ │
	// │ │
	// └────── implements ────────┘
	//
	// • An [ExtensionType] describes a concrete Go implementation of an extension.
	// It has an [ExtensionTypeDescriptor] and can convert to/from
	// an abstract [Value] and a Go value.
	//
	// • An [ExtensionTypeDescriptor] is an [ExtensionDescriptor]
	// which also has an [ExtensionType].
	//
	// • An [ExtensionDescriptor] describes an abstract protobuf extension field and
	// may not always be an [ExtensionTypeDescriptor].
	package protoreflect

	import (
	"fmt"
	"strings"

	"google.golang.org/protobuf/encoding/protowire"
	"google.golang.org/protobuf/internal/pragma"
	)

	type doNotImplement pragma.DoNotImplement

	// ProtoMessage is the top-level interface that all proto messages implement.
	// This is declared in the protoreflect package to avoid a cyclic dependency;
	// use the [google.golang.org/protobuf/proto.Message] type instead, which aliases this type.
	type ProtoMessage interface{ ProtoReflect() Message }

	// Syntax is the language version of the proto file.
	type Syntax syntax

	type syntax int8 // keep exact type opaque as the int type may change

	const (
	Proto2 Syntax = 2
	Proto3 Syntax = 3
	Editions Syntax = 4
	)

	// IsValid reports whether the syntax is valid.
	func (s Syntax) IsValid() bool {
	switch s {
	case Proto2, Proto3, Editions:
	return true
	default:
	return false
	}
	}

	// String returns s as a proto source identifier (e.g., "proto2").
	func (s Syntax) String() string {
	switch s {
	case Proto2:
	return "proto2"
	case Proto3:
	return "proto3"
	case Editions:
	return "editions"
	default:
	return fmt.Sprintf("<unknown:%d>", s)
	}
	}

	// GoString returns s as a Go source identifier (e.g., "Proto2").
	func (s Syntax) GoString() string {
	switch s {
	case Proto2:
	return "Proto2"
	case Proto3:
	return "Proto3"
	default:
	return fmt.Sprintf("Syntax(%d)", s)
	}
	}

	// Cardinality determines whether a field is optional, required, or repeated.
	type Cardinality cardinality

	type cardinality int8 // keep exact type opaque as the int type may change

	// Constants as defined by the google.protobuf.Cardinality enumeration.
	const (
	Optional Cardinality = 1 // appears zero or one times
	Required Cardinality = 2 // appears exactly one time; invalid with Proto3
	Repeated Cardinality = 3 // appears zero or more times
	)

	// IsValid reports whether the cardinality is valid.
	func (c Cardinality) IsValid() bool {
	switch c {
	case Optional, Required, Repeated:
	return true
	default:
	return false
	}
	}

	// String returns c as a proto source identifier (e.g., "optional").
	func (c Cardinality) String() string {
	switch c {
	case Optional:
	return "optional"
	case Required:
	return "required"
	case Repeated:
	return "repeated"
	default:
	return fmt.Sprintf("<unknown:%d>", c)
	}
	}

	// GoString returns c as a Go source identifier (e.g., "Optional").
	func (c Cardinality) GoString() string {
	switch c {
	case Optional:
	return "Optional"
	case Required:
	return "Required"
	case Repeated:
	return "Repeated"
	default:
	return fmt.Sprintf("Cardinality(%d)", c)
	}
	}

	// Kind indicates the basic proto kind of a field.
	type Kind kind

	type kind int8 // keep exact type opaque as the int type may change

	// Constants as defined by the google.protobuf.Field.Kind enumeration.
	const (
	BoolKind Kind = 8
	EnumKind Kind = 14
	Int32Kind Kind = 5
	Sint32Kind Kind = 17
	Uint32Kind Kind = 13
	Int64Kind Kind = 3
	Sint64Kind Kind = 18
	Uint64Kind Kind = 4
	Sfixed32Kind Kind = 15
	Fixed32Kind Kind = 7
	FloatKind Kind = 2
	Sfixed64Kind Kind = 16
	Fixed64Kind Kind = 6
	DoubleKind Kind = 1
	StringKind Kind = 9
	BytesKind Kind = 12
	MessageKind Kind = 11
	GroupKind Kind = 10
	)

	// IsValid reports whether the kind is valid.
	func (k Kind) IsValid() bool {
	switch k {
	case BoolKind, EnumKind,
	Int32Kind, Sint32Kind, Uint32Kind,
	Int64Kind, Sint64Kind, Uint64Kind,
	Sfixed32Kind, Fixed32Kind, FloatKind,
	Sfixed64Kind, Fixed64Kind, DoubleKind,
	StringKind, BytesKind, MessageKind, GroupKind:
	return true
	default:
	return false
	}
	}

	// String returns k as a proto source identifier (e.g., "bool").
	func (k Kind) String() string {
	switch k {
	case BoolKind:
	return "bool"
	case EnumKind:
	return "enum"
	case Int32Kind:
	return "int32"
	case Sint32Kind:
	return "sint32"
	case Uint32Kind:
	return "uint32"
	case Int64Kind:
	return "int64"
	case Sint64Kind:
	return "sint64"
	case Uint64Kind:
	return "uint64"
	case Sfixed32Kind:
	return "sfixed32"
	case Fixed32Kind:
	return "fixed32"
	case FloatKind:
	return "float"
	case Sfixed64Kind:
	return "sfixed64"
	case Fixed64Kind:
	return "fixed64"
	case DoubleKind:
	return "double"
	case StringKind:
	return "string"
	case BytesKind:
	return "bytes"
	case MessageKind:
	return "message"
	case GroupKind:
	return "group"
	default:
	return fmt.Sprintf("<unknown:%d>", k)
	}
	}

	// GoString returns k as a Go source identifier (e.g., "BoolKind").
	func (k Kind) GoString() string {
	switch k {
	case BoolKind:
	return "BoolKind"
	case EnumKind:
	return "EnumKind"
	case Int32Kind:
	return "Int32Kind"
	case Sint32Kind:
	return "Sint32Kind"
	case Uint32Kind:
	return "Uint32Kind"
	case Int64Kind:
	return "Int64Kind"
	case Sint64Kind:
	return "Sint64Kind"
	case Uint64Kind:
	return "Uint64Kind"
	case Sfixed32Kind:
	return "Sfixed32Kind"
	case Fixed32Kind:
	return "Fixed32Kind"
	case FloatKind:
	return "FloatKind"
	case Sfixed64Kind:
	return "Sfixed64Kind"
	case Fixed64Kind:
	return "Fixed64Kind"
	case DoubleKind:
	return "DoubleKind"
	case StringKind:
	return "StringKind"
	case BytesKind:
	return "BytesKind"
	case MessageKind:
	return "MessageKind"
	case GroupKind:
	return "GroupKind"
	default:
	return fmt.Sprintf("Kind(%d)", k)
	}
	}

	// FieldNumber is the field number in a message.
	type FieldNumber = protowire.Number

	// FieldNumbers represent a list of field numbers.
	type FieldNumbers interface {
	// Len reports the number of fields in the list.
	Len() int
	// Get returns the ith field number. It panics if out of bounds.
	Get(i int) FieldNumber
	// Has reports whether n is within the list of fields.
	Has(n FieldNumber) bool

	doNotImplement
	}

	// FieldRanges represent a list of field number ranges.
	type FieldRanges interface {
	// Len reports the number of ranges in the list.
	Len() int
	// Get returns the ith range. It panics if out of bounds.
	Get(i int) [2]FieldNumber // start inclusive; end exclusive
	// Has reports whether n is within any of the ranges.
	Has(n FieldNumber) bool

	doNotImplement
	}

	// EnumNumber is the numeric value for an enum.
	type EnumNumber int32

	// EnumRanges represent a list of enum number ranges.
	type EnumRanges interface {
	// Len reports the number of ranges in the list.
	Len() int
	// Get returns the ith range. It panics if out of bounds.
	Get(i int) [2]EnumNumber // start inclusive; end inclusive
	// Has reports whether n is within any of the ranges.
	Has(n EnumNumber) bool

	doNotImplement
	}

	// Name is the short name for a proto declaration. This is not the name
	// as used in Go source code, which might not be identical to the proto name.
	type Name string // e.g., "Kind"

	// IsValid reports whether s is a syntactically valid name.
	// An empty name is invalid.
	func (s Name) IsValid() bool {
	return consumeIdent(string(s)) == len(s)
	}

	// Names represent a list of names.
	type Names interface {
	// Len reports the number of names in the list.
	Len() int
	// Get returns the ith name. It panics if out of bounds.
	Get(i int) Name
	// Has reports whether s matches any names in the list.
	Has(s Name) bool

	doNotImplement
	}

	// FullName is a qualified name that uniquely identifies a proto declaration.
	// A qualified name is the concatenation of the proto package along with the
	// fully-declared name (i.e., name of parent preceding the name of the child),
	// with a '.' delimiter placed between each [Name].
	//
	// This should not have any leading or trailing dots.
	type FullName string // e.g., "google.protobuf.Field.Kind"

	// IsValid reports whether s is a syntactically valid full name.
	// An empty full name is invalid.
	func (s FullName) IsValid() bool {
	i := consumeIdent(string(s))
	if i < 0 {
	return false
	}
	for len(s) > i {
	if s[i] != '.' {
	return false
	}
	i++
	n := consumeIdent(string(s[i:]))
	if n < 0 {
	return false
	}
	i += n
	}
	return true
	}

	func consumeIdent(s string) (i int) {
	if len(s) == 0 \|\| !isLetter(s[i]) {
	return -1
	}
	i++
	for len(s) > i && isLetterDigit(s[i]) {
	i++
	}
	return i
	}
	func isLetter(c byte) bool {
	return c == '_' \|\| ('a' <= c && c <= 'z') \|\| ('A' <= c && c <= 'Z')
	}
	func isLetterDigit(c byte) bool {
	return isLetter(c) \|\| ('0' <= c && c <= '9')
	}

	// Name returns the short name, which is the last identifier segment.
	// A single segment FullName is the [Name] itself.
	func (n FullName) Name() Name {
	if i := strings.LastIndexByte(string(n), '.'); i >= 0 {
	return Name(n[i+1:])
	}
	return Name(n)
	}

	// Parent returns the full name with the trailing identifier removed.
	// A single segment FullName has no parent.
	func (n FullName) Parent() FullName {
	if i := strings.LastIndexByte(string(n), '.'); i >= 0 {
	return n[:i]
	}
	return ""
	}

	// Append returns the qualified name appended with the provided short name.
	//
	// Invariant: n == n.Parent().Append(n.Name()) // assuming n is valid
	func (n FullName) Append(s Name) FullName {
	if n == "" {
	return FullName(s)
	}
	return n + "." + FullName(s)
	}