-
Notifications
You must be signed in to change notification settings - Fork 30
/
reusable_read_closer.go
102 lines (84 loc) · 2.13 KB
/
reusable_read_closer.go
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
package reader
import (
"bytes"
"errors"
"fmt"
"io"
"strings"
"sync"
)
// ReusableReadCloser is a reusable reader with no-op close
type ReusableReadCloser struct {
*sync.RWMutex
io.Reader
readBuf *bytes.Buffer
backBuf *bytes.Buffer
}
// NewReusableReadCloser is returned for any type of input
func NewReusableReadCloser(raw interface{}) (*ReusableReadCloser, error) {
readBuf := bytes.Buffer{}
backBuf := bytes.Buffer{}
if raw != nil {
switch body := raw.(type) {
case []byte:
// if a byte array , create buffer from bytes and use it
readBuf = *bytes.NewBuffer(body)
case *[]byte:
// if *[]byte, create buffer from bytes and use it
readBuf = *bytes.NewBuffer(*body)
case string:
// if a string , create buffer from string and use it
readBuf = *bytes.NewBufferString(body)
case *bytes.Buffer:
// if *bytes.Buffer is given , use it
readBuf = *body
case *bytes.Reader:
// if *bytes.Reader , make buffer read from reader
if _, er := readBuf.ReadFrom(body); er != nil {
return nil, er
}
case *strings.Reader:
// if *strings.Reader , make buffer read from reader
if _, er := readBuf.ReadFrom(body); er != nil {
return nil, er
}
case io.ReadSeeker:
// if io.ReadSeeker , make buffer read from reader
if _, er := readBuf.ReadFrom(body); er != nil {
return nil, er
}
case io.Reader:
// if io.Reader , make buffer read from reader
if _, er := readBuf.ReadFrom(body); er != nil {
return nil, er
}
default:
// type not implemented or cannot handle
return nil, fmt.Errorf("cannot handle type %T", body)
}
}
reusableReadCloser := &ReusableReadCloser{
&sync.RWMutex{},
io.TeeReader(&readBuf, &backBuf),
&readBuf,
&backBuf,
}
return reusableReadCloser, nil
}
// Read []byte from Reader
func (r ReusableReadCloser) Read(p []byte) (int, error) {
r.Lock()
defer r.Unlock()
n, err := r.Reader.Read(p)
if errors.Is(err, io.EOF) {
r.reset()
}
return n, err
}
func (r ReusableReadCloser) reset() {
_, _ = io.Copy(r.readBuf, r.backBuf)
}
// Close is a no-op close of ReusableReadCloser
func (r ReusableReadCloser) Close() error {
return nil
}