FedP2P/storage/piece_file.go

112 lines
2.4 KiB
Go

package storage
import (
"errors"
"io"
"os"
"path"
"github.com/anacrolix/missinggo"
"github.com/anacrolix/torrent/metainfo"
)
type pieceFileStorage struct {
fs missinggo.FileStore
}
func NewFileStorePieces(fs missinggo.FileStore) Client {
return &pieceFileStorage{
fs: fs,
}
}
type pieceFileTorrentStorage struct {
s *pieceFileStorage
}
func (s *pieceFileStorage) OpenTorrent(info *metainfo.InfoEx) (Torrent, error) {
return &pieceFileTorrentStorage{s}, nil
}
func (s *pieceFileTorrentStorage) Close() error {
return nil
}
func (s *pieceFileTorrentStorage) Piece(p metainfo.Piece) Piece {
return pieceFileTorrentStoragePiece{s, p, s.s.fs}
}
type pieceFileTorrentStoragePiece struct {
ts *pieceFileTorrentStorage
p metainfo.Piece
fs missinggo.FileStore
}
func (s pieceFileTorrentStoragePiece) completedPath() string {
return path.Join("completed", s.p.Hash().HexString())
}
func (s pieceFileTorrentStoragePiece) incompletePath() string {
return path.Join("incomplete", s.p.Hash().HexString())
}
func (s pieceFileTorrentStoragePiece) GetIsComplete() bool {
fi, err := s.fs.Stat(s.completedPath())
return err == nil && fi.Size() == s.p.Length()
}
func (s pieceFileTorrentStoragePiece) MarkComplete() error {
return s.fs.Rename(s.incompletePath(), s.completedPath())
}
func (s pieceFileTorrentStoragePiece) openFile() (f missinggo.File, err error) {
f, err = s.fs.OpenFile(s.completedPath(), os.O_RDONLY)
if err == nil {
var fi os.FileInfo
fi, err = f.Stat()
if err == nil && fi.Size() == s.p.Length() {
return
}
f.Close()
} else if !os.IsNotExist(err) {
return
}
f, err = s.fs.OpenFile(s.incompletePath(), os.O_RDONLY)
if os.IsNotExist(err) {
err = io.ErrUnexpectedEOF
}
return
}
func (s pieceFileTorrentStoragePiece) ReadAt(b []byte, off int64) (n int, err error) {
f, err := s.openFile()
if err != nil {
return
}
defer f.Close()
missinggo.LimitLen(&b, s.p.Length()-off)
n, err = f.ReadAt(b, off)
off += int64(n)
if off >= s.p.Length() {
err = io.EOF
} else if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return
}
func (s pieceFileTorrentStoragePiece) WriteAt(b []byte, off int64) (n int, err error) {
if s.GetIsComplete() {
err = errors.New("piece completed")
return
}
f, err := s.fs.OpenFile(s.incompletePath(), os.O_WRONLY|os.O_CREATE)
if err != nil {
return
}
defer f.Close()
missinggo.LimitLen(&b, s.p.Length()-off)
return f.WriteAt(b, off)
}