torrent/data/file/file.go

115 lines
1.9 KiB
Go

package file
import (
"io"
"os"
"path/filepath"
"github.com/anacrolix/torrent/metainfo"
)
type data struct {
info *metainfo.Info
loc string
}
func TorrentData(md *metainfo.Info, location string) data {
return data{md, location}
}
func (me data) ReadAt(p []byte, off int64) (n int, err error) {
for _, fi := range me.info.UpvertedFiles() {
if off >= fi.Length {
off -= fi.Length
continue
}
n1 := len(p)
if int64(n1) > fi.Length-off {
n1 = int(fi.Length - off)
}
var f *os.File
f, err = os.Open(me.fileInfoName(fi))
if err != nil {
return
}
n1, err = f.ReadAt(p[:n1], off)
f.Close()
if err != nil {
return
}
n += n1
off = 0
p = p[n1:]
if len(p) == 0 {
break
}
}
return
}
func (me data) WriteAt(p []byte, off int64) (n int, err error) {
for _, fi := range me.info.UpvertedFiles() {
if off >= fi.Length {
off -= fi.Length
continue
}
n1 := len(p)
if int64(n1) > fi.Length-off {
n1 = int(fi.Length - off)
}
name := me.fileInfoName(fi)
os.MkdirAll(filepath.Dir(name), 0770)
var f *os.File
f, err = os.OpenFile(name, os.O_WRONLY|os.O_CREATE, 0660)
if err != nil {
return
}
n1, err = f.WriteAt(p[:n1], off)
f.Close()
if err != nil {
return
}
n += n1
off = 0
p = p[n1:]
if len(p) == 0 {
break
}
}
return
}
func (me data) WriteSectionTo(w io.Writer, off, n int64) (written int64, err error) {
for _, fi := range me.info.UpvertedFiles() {
if off >= fi.Length {
off -= fi.Length
continue
}
n1 := fi.Length - off
if n1 > n {
n1 = n
}
var f *os.File
f, err = os.Open(me.fileInfoName(fi))
if err != nil {
return
}
n1, err = io.Copy(w, io.NewSectionReader(f, off, n1))
f.Close()
if err != nil {
return
}
written += n1
off = 0
n -= n1
if n == 0 {
break
}
}
return
}
func (me data) fileInfoName(fi metainfo.FileInfo) string {
return filepath.Join(append([]string{me.loc, me.info.Name}, fi.Path...)...)
}