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
|
// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package util
import (
"bytes"
"errors"
"io"
)
// ReadAtMost reads at most len(buf) bytes from r into buf.
// It returns the number of bytes copied. n is only less than len(buf) if r provides fewer bytes.
// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil.
func ReadAtMost(r io.Reader, buf []byte) (n int, err error) {
n, err = io.ReadFull(r, buf)
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = nil
}
return n, err
}
// ReadWithLimit reads at most "limit" bytes from r into buf.
// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil.
func ReadWithLimit(r io.Reader, n int) (buf []byte, err error) {
return readWithLimit(r, 1024, n)
}
func readWithLimit(r io.Reader, batch, limit int) ([]byte, error) {
if limit <= batch {
buf := make([]byte, limit)
n, err := ReadAtMost(r, buf)
if err != nil {
return nil, err
}
return buf[:n], nil
}
res := bytes.NewBuffer(make([]byte, 0, batch))
bufFix := make([]byte, batch)
eof := false
for res.Len() < limit && !eof {
bufTmp := bufFix
if res.Len()+batch > limit {
bufTmp = bufFix[:limit-res.Len()]
}
n, err := io.ReadFull(r, bufTmp)
if err == io.EOF || err == io.ErrUnexpectedEOF {
eof = true
} else if err != nil {
return nil, err
}
if _, err = res.Write(bufTmp[:n]); err != nil {
return nil, err
}
}
return res.Bytes(), nil
}
// ErrNotEmpty is an error reported when there is a non-empty reader
var ErrNotEmpty = errors.New("not-empty")
// IsEmptyReader reads a reader and ensures it is empty
func IsEmptyReader(r io.Reader) (err error) {
var buf [1]byte
for {
n, err := r.Read(buf[:])
if err != nil {
if err == io.EOF {
return nil
}
return err
}
if n > 0 {
return ErrNotEmpty
}
}
}
|
