blob: 66b97a6f692a6a081f8b1c77182dd914711cfbc3 [file] [log] [blame]
Holger Hildebrandtfa074992020-03-27 15:42:06 +00001/*
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.
21package proto
22
23import (
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.
32const Name = "proto"
33
34func init() {
35 encoding.RegisterCodec(codec{})
36}
37
38// codec is a Codec implementation with protobuf. It is the default codec for gRPC.
39type codec struct{}
40
41type cachedProtoBuffer struct {
42 lastMarshaledSize uint32
43 proto.Buffer
44}
45
46func capToMaxInt32(val int) uint32 {
47 if val > math.MaxInt32 {
48 return uint32(math.MaxInt32)
49 }
50 return uint32(val)
51}
52
53func 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
67func (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
82func (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
99func (codec) Name() string {
100 return Name
101}
102
103var protoBufferPool = &sync.Pool{
104 New: func() interface{} {
105 return &cachedProtoBuffer{
106 Buffer: proto.Buffer{},
107 lastMarshaledSize: 16,
108 }
109 },
110}