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
127
128
129
130
131
132
133
134
135
136
|
// Package streamio contains wrappers intended for turning gRPC streams
// that send/receive messages with a []byte field into io.Writers and
// io.Readers.
//
package streamio
import (
"io"
"os"
"strconv"
)
func init() {
bufSize64, err := strconv.ParseInt(os.Getenv("GITALY_STREAMIO_WRITE_BUFFER_SIZE"), 10, 32)
if err == nil && bufSize64 > 0 {
WriteBufferSize = int(bufSize64)
}
}
// NewReader turns receiver into an io.Reader. Errors from the receiver
// function are passed on unmodified. This means receiver should emit
// io.EOF when done.
func NewReader(receiver func() ([]byte, error)) io.Reader {
return &receiveReader{receiver: receiver}
}
type receiveReader struct {
receiver func() ([]byte, error)
data []byte
err error
}
func (rr *receiveReader) Read(p []byte) (int, error) {
if len(rr.data) == 0 {
rr.data, rr.err = rr.receiver()
}
n := copy(p, rr.data)
rr.data = rr.data[n:]
if len(rr.data) == 0 {
return n, rr.err
}
return n, nil
}
// WriteTo implements io.WriterTo.
func (rr *receiveReader) WriteTo(w io.Writer) (int64, error) {
var written int64
// Deal with left-over state in rr.data and rr.err, if any
if len(rr.data) > 0 {
n, err := w.Write(rr.data)
written += int64(n)
if err != nil {
return written, err
}
}
if rr.err != nil {
return written, rr.err
}
// Consume the response stream
var errRead, errWrite error
var n int
var buf []byte
for errWrite == nil && errRead != io.EOF {
buf, errRead = rr.receiver()
if errRead != nil && errRead != io.EOF {
return written, errRead
}
if len(buf) > 0 {
n, errWrite = w.Write(buf)
written += int64(n)
}
}
return written, errWrite
}
// NewWriter turns sender into an io.Writer. The sender callback will
// receive []byte arguments of length at most WriteBufferSize.
func NewWriter(sender func(p []byte) error) io.Writer {
return &sendWriter{sender: sender}
}
// WriteBufferSize is the largest []byte that Write() will pass to its
// underlying send function. This value can be changed at runtime using
// the GITALY_STREAMIO_WRITE_BUFFER_SIZE environment variable.
var WriteBufferSize = 128 * 1024
type sendWriter struct {
sender func([]byte) error
}
func (sw *sendWriter) Write(p []byte) (int, error) {
var sent int
for len(p) > 0 {
chunkSize := len(p)
if chunkSize > WriteBufferSize {
chunkSize = WriteBufferSize
}
if err := sw.sender(p[:chunkSize]); err != nil {
return sent, err
}
sent += chunkSize
p = p[chunkSize:]
}
return sent, nil
}
// ReadFrom implements io.ReaderFrom.
func (sw *sendWriter) ReadFrom(r io.Reader) (int64, error) {
var nRead int64
buf := make([]byte, WriteBufferSize)
var errRead, errSend error
for errSend == nil && errRead != io.EOF {
var n int
n, errRead = r.Read(buf)
nRead += int64(n)
if errRead != nil && errRead != io.EOF {
return nRead, errRead
}
if n > 0 {
errSend = sw.sender(buf[:n])
}
}
return nRead, errSend
}
|