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/*
*
* Copyright 2018 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 proto defines the protobuf codec. Importing this package will
// register the codec.
package proto
import (
"math"
"sync"
"github.com/golang/protobuf/proto"
"google.golang.org/grpc/encoding"
)
// Name is the name registered for the proto compressor.
const Name = "proto"
func init() {
encoding.RegisterCodec(codec{})
}
// codec is a Codec implementation with protobuf. It is the default codec for gRPC.
type codec 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 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 (codec) 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 := marshal(v, cb)
// put back buffer and lose the ref to the slice
cb.SetBuf(nil)
protoBufferPool.Put(cb)
return out, err
}
func (codec) 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 (codec) Name() string {
return Name
}
var protoBufferPool = &sync.Pool{
New: func() interface{} {
return &cachedProtoBuffer{
Buffer: proto.Buffer{},
lastMarshaledSize: 16,
}
},
}
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