// Copyright 2019 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 protoiface contains types referenced or implemented by messages.

//

// WARNING: This package should only be imported by message implementations.

// The functionality found in this package should be accessed through

// higher-level abstractions provided by the proto package.

package protoiface

import (

	"google.golang.org/protobuf/internal/pragma"

	"google.golang.org/protobuf/reflect/protoreflect"

)

// Methods is a set of optional fast-path implementations of various operations.

type Methods = struct {

	pragma.NoUnkeyedLiterals

	// Flags indicate support for optional features.

	Flags SupportFlags

	// Size returns the size in bytes of the wire-format encoding of a message.

	// Marshal must be provided if a custom Size is provided.

	Size func(SizeInput) SizeOutput

	// Marshal formats a message in the wire-format encoding to the provided buffer.

	// Size should be provided if a custom Marshal is provided.

	// It must not return an error for a partial message.

	Marshal func(MarshalInput) (MarshalOutput, error)

	// Unmarshal parses the wire-format encoding and merges the result into a message.

	// It must not reset the target message or return an error for a partial message.

	Unmarshal func(UnmarshalInput) (UnmarshalOutput, error)

	// Merge merges the contents of a source message into a destination message.

	Merge func(MergeInput) MergeOutput

	// CheckInitialized returns an error if any required fields in the message are not set.

	CheckInitialized func(CheckInitializedInput) (CheckInitializedOutput, error)

}

// SupportFlags indicate support for optional features.

type SupportFlags = uint64

const (

	// SupportMarshalDeterministic reports whether MarshalOptions.Deterministic is supported.

	SupportMarshalDeterministic SupportFlags = 1 << iota

	// SupportUnmarshalDiscardUnknown reports whether UnmarshalOptions.DiscardUnknown is supported.

	SupportUnmarshalDiscardUnknown

)

// SizeInput is input to the Size method.

type SizeInput = struct {

	pragma.NoUnkeyedLiterals

	Message protoreflect.Message

	Flags   MarshalInputFlags

}

// SizeOutput is output from the Size method.

type SizeOutput = struct {

	pragma.NoUnkeyedLiterals

	Size int

}

// MarshalInput is input to the Marshal method.

type MarshalInput = struct {

	pragma.NoUnkeyedLiterals

	Message protoreflect.Message

	Buf     []byte // output is appended to this buffer

	Flags   MarshalInputFlags

}

// MarshalOutput is output from the Marshal method.

type MarshalOutput = struct {

	pragma.NoUnkeyedLiterals

	Buf []byte // contains marshaled message

}

// MarshalInputFlags configure the marshaler.

// Most flags correspond to fields in proto.MarshalOptions.

type MarshalInputFlags = uint8

const (

	MarshalDeterministic MarshalInputFlags = 1 << iota

	MarshalUseCachedSize

)

// UnmarshalInput is input to the Unmarshal method.

type UnmarshalInput = struct {

	pragma.NoUnkeyedLiterals

	Message  protoreflect.Message

	Buf      []byte // input buffer

	Flags    UnmarshalInputFlags

	Resolver interface {

		FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error)

		FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error)

	}

}

// UnmarshalOutput is output from the Unmarshal method.

type UnmarshalOutput = struct {

	pragma.NoUnkeyedLiterals

	Flags UnmarshalOutputFlags

}

// UnmarshalInputFlags configure the unmarshaler.

// Most flags correspond to fields in proto.UnmarshalOptions.

type UnmarshalInputFlags = uint8

const (

	UnmarshalDiscardUnknown UnmarshalInputFlags = 1 << iota

)

// UnmarshalOutputFlags are output from the Unmarshal method.

type UnmarshalOutputFlags = uint8

const (

	// UnmarshalInitialized may be set on return if all required fields are known to be set.

	// If unset, then it does not necessarily indicate that the message is uninitialized,

	// only that its status could not be confirmed.

	UnmarshalInitialized UnmarshalOutputFlags = 1 << iota

)

// MergeInput is input to the Merge method.

type MergeInput = struct {

	pragma.NoUnkeyedLiterals

	Source      protoreflect.Message

	Destination protoreflect.Message

}

// MergeOutput is output from the Merge method.

type MergeOutput = struct {

	pragma.NoUnkeyedLiterals

	Flags MergeOutputFlags

}

// MergeOutputFlags are output from the Merge method.

type MergeOutputFlags = uint8

const (

	// MergeComplete reports whether the merge was performed.

	// If unset, the merger must have made no changes to the destination.

	MergeComplete MergeOutputFlags = 1 << iota

)

// CheckInitializedInput is input to the CheckInitialized method.

type CheckInitializedInput = struct {

	pragma.NoUnkeyedLiterals

	Message protoreflect.Message

}

// CheckInitializedOutput is output from the CheckInitialized method.

type CheckInitializedOutput = struct {

	pragma.NoUnkeyedLiterals

}