mirror of
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120 lines
3.5 KiB
Go
120 lines
3.5 KiB
Go
/*
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*
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* Copyright 2014, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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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