104 lines
2.6 KiB
Go
104 lines
2.6 KiB
Go
/*
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*
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* Copyright 2014 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package grpc
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import (
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"math"
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"sync"
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"github.com/golang/protobuf/proto"
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)
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// Codec defines the interface gRPC uses to encode and decode messages.
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// Note that implementations of this interface must be thread safe;
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// a Codec's methods can be called from concurrent goroutines.
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type Codec interface {
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// Marshal returns the wire format of v.
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Marshal(v interface{}) ([]byte, error)
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// Unmarshal parses the wire format into v.
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Unmarshal(data []byte, v interface{}) error
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// String returns the name of the Codec implementation. The returned
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// string will be used as part of content type in transmission.
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String() string
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}
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// protoCodec is a Codec implementation with protobuf. It is the default codec for gRPC.
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type protoCodec struct {
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}
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type cachedProtoBuffer struct {
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lastMarshaledSize uint32
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proto.Buffer
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}
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func capToMaxInt32(val int) uint32 {
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if val > math.MaxInt32 {
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return uint32(math.MaxInt32)
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}
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return uint32(val)
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}
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func (p protoCodec) marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) {
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protoMsg := v.(proto.Message)
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newSlice := make([]byte, 0, cb.lastMarshaledSize)
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cb.SetBuf(newSlice)
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cb.Reset()
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if err := cb.Marshal(protoMsg); err != nil {
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return nil, err
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}
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out := cb.Bytes()
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cb.lastMarshaledSize = capToMaxInt32(len(out))
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return out, nil
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}
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func (p protoCodec) Marshal(v interface{}) ([]byte, error) {
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cb := protoBufferPool.Get().(*cachedProtoBuffer)
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out, err := p.marshal(v, cb)
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// put back buffer and lose the ref to the slice
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cb.SetBuf(nil)
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protoBufferPool.Put(cb)
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return out, err
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}
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func (p protoCodec) Unmarshal(data []byte, v interface{}) error {
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cb := protoBufferPool.Get().(*cachedProtoBuffer)
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cb.SetBuf(data)
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v.(proto.Message).Reset()
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err := cb.Unmarshal(v.(proto.Message))
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cb.SetBuf(nil)
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protoBufferPool.Put(cb)
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return err
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}
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func (protoCodec) String() string {
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return "proto"
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}
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var (
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protoBufferPool = &sync.Pool{
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New: func() interface{} {
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return &cachedProtoBuffer{
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Buffer: proto.Buffer{},
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lastMarshaledSize: 16,
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}
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},
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}
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)
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