-
Notifications
You must be signed in to change notification settings - Fork 42
/
line-writer.go
62 lines (56 loc) · 1.13 KB
/
line-writer.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
package utils
import (
"io/fs"
"os"
)
type fileLineWriter struct {
*os.File
flag int
firstLine bool
}
func NewFileLineWriter(file string, flag int, perm fs.FileMode) (*fileLineWriter, error) {
f, err := os.OpenFile(file, flag, perm)
if err != nil {
return nil, err
}
// 追加时,假如最后一个字符不是换行符,则添加换行符
if flag&os.O_APPEND != 0 {
state, err := f.Stat()
if err != nil {
return nil, err
}
buf := make([]byte, 1)
f.ReadAt(buf, state.Size()-1)
if buf[0] != '\n' {
_, err := f.WriteString("\n")
if err != nil {
return nil, err
}
}
}
return &fileLineWriter{File: f, flag: flag, firstLine: true}, nil
}
func (w *fileLineWriter) WriteLine(line []byte) (n int, err error) {
if w.firstLine {
w.firstLine = false
} else {
n, err = w.File.WriteString("\n")
}
n, err = w.File.Write(line)
if err != nil {
return
}
return
}
func (w *fileLineWriter) WriteLineString(line string) (n int, err error) {
if w.firstLine {
w.firstLine = false
} else {
n, err = w.File.WriteString("\n")
}
n, err = w.File.WriteString(line)
if err != nil {
return
}
return
}