1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
// Copyright 2022, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package gax
import (
"encoding/json"
"errors"
"io"
"google.golang.org/protobuf/encoding/protojson"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
)
var (
arrayOpen = json.Delim('[')
arrayClose = json.Delim(']')
errBadOpening = errors.New("unexpected opening token, expected '['")
)
// ProtoJSONStream represents a wrapper for consuming a stream of protobuf
// messages encoded using protobuf-JSON format. More information on this format
// can be found at https://developers.google.com/protocol-buffers/docs/proto3#json.
// The stream must appear as a comma-delimited, JSON array of obbjects with
// opening and closing square braces.
//
// This is for internal use only.
type ProtoJSONStream struct {
first, closed bool
reader io.ReadCloser
stream *json.Decoder
typ protoreflect.MessageType
}
// NewProtoJSONStreamReader accepts a stream of bytes via an io.ReadCloser that are
// protobuf-JSON encoded protobuf messages of the given type. The ProtoJSONStream
// must be closed when done.
//
// This is for internal use only.
func NewProtoJSONStreamReader(rc io.ReadCloser, typ protoreflect.MessageType) *ProtoJSONStream {
return &ProtoJSONStream{
first: true,
reader: rc,
stream: json.NewDecoder(rc),
typ: typ,
}
}
// Recv decodes the next protobuf message in the stream or returns io.EOF if
// the stream is done. It is not safe to call Recv on the same stream from
// different goroutines, just like it is not safe to do so with a single gRPC
// stream. Type-cast the protobuf message returned to the type provided at
// ProtoJSONStream creation.
// Calls to Recv after calling Close will produce io.EOF.
func (s *ProtoJSONStream) Recv() (proto.Message, error) {
if s.closed {
return nil, io.EOF
}
if s.first {
s.first = false
// Consume the opening '[' so Decode gets one object at a time.
if t, err := s.stream.Token(); err != nil {
return nil, err
} else if t != arrayOpen {
return nil, errBadOpening
}
}
// Capture the next block of data for the item (a JSON object) in the stream.
var raw json.RawMessage
if err := s.stream.Decode(&raw); err != nil {
e := err
// To avoid checking the first token of each stream, just attempt to
// Decode the next blob and if that fails, double check if it is just
// the closing token ']'. If it is the closing, return io.EOF. If it
// isn't, return the original error.
if t, _ := s.stream.Token(); t == arrayClose {
e = io.EOF
}
return nil, e
}
// Initialize a new instance of the protobuf message to unmarshal the
// raw data into.
m := s.typ.New().Interface()
err := protojson.Unmarshal(raw, m)
return m, err
}
// Close closes the stream so that resources are cleaned up.
func (s *ProtoJSONStream) Close() error {
// Dereference the *json.Decoder so that the memory is gc'd.
s.stream = nil
s.closed = true
return s.reader.Close()
}
|
