115 lines
2.8 KiB
Go
115 lines
2.8 KiB
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 (
|
|
"math"
|
|
"sync"
|
|
|
|
"github.com/golang/protobuf/proto"
|
|
)
|
|
|
|
// 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.
|
|
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. The returned
|
|
// string will be used as part of content type in transmission.
|
|
String() string
|
|
}
|
|
|
|
// protoCodec is a Codec implementation with protobuf. It is the default codec for gRPC.
|
|
type protoCodec struct {
|
|
}
|
|
|
|
type cachedProtoBuffer struct {
|
|
lastMarshaledSize uint32
|
|
proto.Buffer
|
|
}
|
|
|
|
func capToMaxInt32(val int) uint32 {
|
|
if val > math.MaxInt32 {
|
|
return uint32(math.MaxInt32)
|
|
}
|
|
return uint32(val)
|
|
}
|
|
|
|
func (p protoCodec) marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) {
|
|
protoMsg := v.(proto.Message)
|
|
newSlice := make([]byte, 0, cb.lastMarshaledSize)
|
|
|
|
cb.SetBuf(newSlice)
|
|
cb.Reset()
|
|
if err := cb.Marshal(protoMsg); err != nil {
|
|
return nil, err
|
|
}
|
|
out := cb.Bytes()
|
|
cb.lastMarshaledSize = capToMaxInt32(len(out))
|
|
return out, nil
|
|
}
|
|
|
|
func (p protoCodec) Marshal(v interface{}) ([]byte, error) {
|
|
if pm, ok := v.(proto.Marshaler); ok {
|
|
// object can marshal itself, no need for buffer
|
|
return pm.Marshal()
|
|
}
|
|
|
|
cb := protoBufferPool.Get().(*cachedProtoBuffer)
|
|
out, err := p.marshal(v, cb)
|
|
|
|
// put back buffer and lose the ref to the slice
|
|
cb.SetBuf(nil)
|
|
protoBufferPool.Put(cb)
|
|
return out, err
|
|
}
|
|
|
|
func (p protoCodec) Unmarshal(data []byte, v interface{}) error {
|
|
protoMsg := v.(proto.Message)
|
|
protoMsg.Reset()
|
|
|
|
if pu, ok := protoMsg.(proto.Unmarshaler); ok {
|
|
// object can unmarshal itself, no need for buffer
|
|
return pu.Unmarshal(data)
|
|
}
|
|
|
|
cb := protoBufferPool.Get().(*cachedProtoBuffer)
|
|
cb.SetBuf(data)
|
|
err := cb.Unmarshal(protoMsg)
|
|
cb.SetBuf(nil)
|
|
protoBufferPool.Put(cb)
|
|
return err
|
|
}
|
|
|
|
func (protoCodec) String() string {
|
|
return "proto"
|
|
}
|
|
|
|
var protoBufferPool = &sync.Pool{
|
|
New: func() interface{} {
|
|
return &cachedProtoBuffer{
|
|
Buffer: proto.Buffer{},
|
|
lastMarshaledSize: 16,
|
|
}
|
|
},
|
|
}
|