/
file.go
165 lines (148 loc) · 3.1 KB
/
file.go
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package storage
import (
"io"
"os"
"path/filepath"
"github.com/anacrolix/missinggo"
"github.com/anacrolix/torrent/metainfo"
)
type fileStorage struct {
baseDir string
completed map[[20]byte]bool
}
func NewFile(baseDir string) I {
return &fileStorage{
baseDir: baseDir,
}
}
func (me *fileStorage) OpenTorrent(info *metainfo.InfoEx) (Torrent, error) {
return fileTorrentStorage{me}, nil
}
type fileTorrentStorage struct {
*fileStorage
}
func (me *fileStorage) Piece(p metainfo.Piece) Piece {
_io := &fileStorageTorrent{
p.Info,
me.baseDir,
}
return &fileStoragePiece{
me,
p,
missinggo.NewSectionWriter(_io, p.Offset(), p.Length()),
io.NewSectionReader(_io, p.Offset(), p.Length()),
}
}
func (me *fileStorage) Close() error {
return nil
}
type fileStoragePiece struct {
*fileStorage
p metainfo.Piece
io.WriterAt
io.ReaderAt
}
func (me *fileStoragePiece) GetIsComplete() bool {
return me.completed[me.p.Hash()]
}
func (me *fileStoragePiece) MarkComplete() error {
if me.completed == nil {
me.completed = make(map[[20]byte]bool)
}
me.completed[me.p.Hash()] = true
return nil
}
type fileStorageTorrent struct {
info *metainfo.InfoEx
baseDir string
}
// Returns EOF on short or missing file.
func (me *fileStorageTorrent) readFileAt(fi metainfo.FileInfo, b []byte, off int64) (n int, err error) {
f, err := os.Open(me.fileInfoName(fi))
if os.IsNotExist(err) {
// File missing is treated the same as a short file.
err = io.EOF
return
}
if err != nil {
return
}
defer f.Close()
// Limit the read to within the expected bounds of this file.
if int64(len(b)) > fi.Length-off {
b = b[:fi.Length-off]
}
for off < fi.Length && len(b) != 0 {
n1, err1 := f.ReadAt(b, off)
b = b[n1:]
n += n1
off += int64(n1)
if n1 == 0 {
err = err1
break
}
}
return
}
// Only returns EOF at the end of the torrent. Premature EOF is ErrUnexpectedEOF.
func (me *fileStorageTorrent) ReadAt(b []byte, off int64) (n int, err error) {
for _, fi := range me.info.UpvertedFiles() {
for off < fi.Length {
n1, err1 := me.readFileAt(fi, b, off)
n += n1
off += int64(n1)
b = b[n1:]
if len(b) == 0 {
// Got what we need.
return
}
if n1 != 0 {
// Made progress.
continue
}
err = err1
if err == io.EOF {
// Lies.
err = io.ErrUnexpectedEOF
}
return
}
off -= fi.Length
}
err = io.EOF
return
}
func (me *fileStorageTorrent) 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 *fileStorageTorrent) fileInfoName(fi metainfo.FileInfo) string {
return filepath.Join(append([]string{me.baseDir, me.info.Name}, fi.Path...)...)
}