mirror of https://github.com/docker/cli.git
111 lines
2.5 KiB
Go
111 lines
2.5 KiB
Go
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/*
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*
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* Copyright 2018 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 proto defines the protobuf codec. Importing this package will
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// register the codec.
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package proto
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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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"google.golang.org/grpc/encoding"
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)
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// Name is the name registered for the proto compressor.
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const Name = "proto"
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func init() {
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encoding.RegisterCodec(codec{})
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}
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// codec is a Codec implementation with protobuf. It is the default codec for gRPC.
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type codec struct{}
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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 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 (codec) Marshal(v interface{}) ([]byte, error) {
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if pm, ok := v.(proto.Marshaler); ok {
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// object can marshal itself, no need for buffer
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return pm.Marshal()
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}
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cb := protoBufferPool.Get().(*cachedProtoBuffer)
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out, err := 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 (codec) Unmarshal(data []byte, v interface{}) error {
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protoMsg := v.(proto.Message)
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protoMsg.Reset()
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if pu, ok := protoMsg.(proto.Unmarshaler); ok {
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// object can unmarshal itself, no need for buffer
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return pu.Unmarshal(data)
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}
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cb := protoBufferPool.Get().(*cachedProtoBuffer)
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cb.SetBuf(data)
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err := cb.Unmarshal(protoMsg)
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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 (codec) Name() string {
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return Name
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}
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var 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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