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FilePrepend.go
77 lines (64 loc) · 1.25 KB
/
FilePrepend.go
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package common
import (
"bufio"
"fmt"
"os"
)
type Record struct {
Filename string
Contents []string
}
var NewRecord = func(filename string) *Record {
return &Record{
Filename: filename,
Contents: make([]string, 0),
}
}
func (r *Record) readLines() error {
if _, err := os.Stat(r.Filename); err != nil {
return nil
}
f, err := os.OpenFile(r.Filename, os.O_RDONLY, 0600)
if err != nil {
return err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
if tmp := scanner.Text(); len(tmp) != 0 {
r.Contents = append(r.Contents, tmp)
}
}
return nil
}
func (r *Record) Prepend(content string) error {
err := r.readLines()
if err != nil {
return err
}
f, err := os.OpenFile(r.Filename, os.O_CREATE|os.O_WRONLY, 0600)
if err != nil {
return err
}
defer f.Close()
writer := bufio.NewWriter(f)
writer.WriteString(fmt.Sprintf("%s\n", content))
for _, line := range r.Contents {
_, err := writer.WriteString(fmt.Sprintf("%s\n", line))
if err != nil {
return err
}
}
if err := writer.Flush(); err != nil {
return err
}
return nil
}
var PrependToFile = func(filename, content string) error {
record := NewRecord(filename)
err := record.Prepend(content)
if err != nil {
return err
}
return nil
}