Takahiro Suzuki | d7bf820 | 2020-12-17 20:21:59 +0900 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2018 gRPC authors. |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | // Package proto defines the protobuf codec. Importing this package will |
| 20 | // register the codec. |
| 21 | package proto |
| 22 | |
| 23 | import ( |
| 24 | "math" |
| 25 | "sync" |
| 26 | |
| 27 | "github.com/golang/protobuf/proto" |
| 28 | "google.golang.org/grpc/encoding" |
| 29 | ) |
| 30 | |
| 31 | // Name is the name registered for the proto compressor. |
| 32 | const Name = "proto" |
| 33 | |
| 34 | func init() { |
| 35 | encoding.RegisterCodec(codec{}) |
| 36 | } |
| 37 | |
| 38 | // codec is a Codec implementation with protobuf. It is the default codec for gRPC. |
| 39 | type codec struct{} |
| 40 | |
| 41 | type cachedProtoBuffer struct { |
| 42 | lastMarshaledSize uint32 |
| 43 | proto.Buffer |
| 44 | } |
| 45 | |
| 46 | func capToMaxInt32(val int) uint32 { |
| 47 | if val > math.MaxInt32 { |
| 48 | return uint32(math.MaxInt32) |
| 49 | } |
| 50 | return uint32(val) |
| 51 | } |
| 52 | |
| 53 | func marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) { |
| 54 | protoMsg := v.(proto.Message) |
| 55 | newSlice := make([]byte, 0, cb.lastMarshaledSize) |
| 56 | |
| 57 | cb.SetBuf(newSlice) |
| 58 | cb.Reset() |
| 59 | if err := cb.Marshal(protoMsg); err != nil { |
| 60 | return nil, err |
| 61 | } |
| 62 | out := cb.Bytes() |
| 63 | cb.lastMarshaledSize = capToMaxInt32(len(out)) |
| 64 | return out, nil |
| 65 | } |
| 66 | |
| 67 | func (codec) Marshal(v interface{}) ([]byte, error) { |
| 68 | if pm, ok := v.(proto.Marshaler); ok { |
| 69 | // object can marshal itself, no need for buffer |
| 70 | return pm.Marshal() |
| 71 | } |
| 72 | |
| 73 | cb := protoBufferPool.Get().(*cachedProtoBuffer) |
| 74 | out, err := marshal(v, cb) |
| 75 | |
| 76 | // put back buffer and lose the ref to the slice |
| 77 | cb.SetBuf(nil) |
| 78 | protoBufferPool.Put(cb) |
| 79 | return out, err |
| 80 | } |
| 81 | |
| 82 | func (codec) Unmarshal(data []byte, v interface{}) error { |
| 83 | protoMsg := v.(proto.Message) |
| 84 | protoMsg.Reset() |
| 85 | |
| 86 | if pu, ok := protoMsg.(proto.Unmarshaler); ok { |
| 87 | // object can unmarshal itself, no need for buffer |
| 88 | return pu.Unmarshal(data) |
| 89 | } |
| 90 | |
| 91 | cb := protoBufferPool.Get().(*cachedProtoBuffer) |
| 92 | cb.SetBuf(data) |
| 93 | err := cb.Unmarshal(protoMsg) |
| 94 | cb.SetBuf(nil) |
| 95 | protoBufferPool.Put(cb) |
| 96 | return err |
| 97 | } |
| 98 | |
| 99 | func (codec) Name() string { |
| 100 | return Name |
| 101 | } |
| 102 | |
| 103 | var protoBufferPool = &sync.Pool{ |
| 104 | New: func() interface{} { |
| 105 | return &cachedProtoBuffer{ |
| 106 | Buffer: proto.Buffer{}, |
| 107 | lastMarshaledSize: 16, |
| 108 | } |
| 109 | }, |
| 110 | } |