codec.go

/*
 *
 * Copyright 2014 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package grpc

import (
	"google.golang.org/grpc/encoding"
	_ "google.golang.org/grpc/encoding/proto" // to register the Codec for "proto"
)

// baseCodec contains the functionality of both Codec and encoding.Codec, but
// omits the name/string, which vary between the two and are not needed for
// anything besides the registry in the encoding package.
type baseCodec interface {
	Marshal(v interface{}) ([]byte, error)
	Unmarshal(data []byte, v interface{}) error
}

// A bufferReturner requires a ReturnBuffer method to be implemented. Once a
// Marshal caller is done with the returned byte buffer, they can choose to
// return it back to the encoding library for re-use using this method.
type bufferReturner interface {
	// If implemented in a codec, this function may be called with the byte
	// buffer returned by Marshal after gRPC is done with the buffer.
	//
	// gRPC will not call ReturnBuffer after it's done with the buffer if any of
	// the following is true:
	//   1. Stats handlers are used.
	//   2. Binlogs are enabled.
	ReturnBuffer(buf []byte)
}

var _ baseCodec = Codec(nil)
var _ baseCodec = encoding.Codec(nil)

// Codec defines the interface gRPC uses to encode and decode messages.
// Note that implementations of this interface must be thread safe;
// a Codec's methods can be called from concurrent goroutines.
//
// Deprecated: use encoding.Codec instead.
type Codec interface {
	// Marshal returns the wire format of v.
	Marshal(v interface{}) ([]byte, error)
	// Unmarshal parses the wire format into v.
	Unmarshal(data []byte, v interface{}) error
	// String returns the name of the Codec implementation.  This is unused by
	// gRPC.
	String() string
}