// 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 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.

//

// • A MessageDescriptor describes an abstract protobuf message type.

//

// • A Message is a concrete message instance. Generated messages implement

// ProtoMessage, which can convert to/from a Message.

//

//

//	      ┌── 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

// abstract Values and Go values.

//

// • 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 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

)

// IsValid reports whether the syntax is valid.

func (s Syntax) IsValid() bool {

	switch s {

	case Proto2, Proto3:

		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"

	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) {