torrent/storage/wrappers.go

83 lines
1.4 KiB
Go

package storage
import (
"errors"
"io"
"os"
"github.com/anacrolix/missinggo"
"github.com/anacrolix/torrent/metainfo"
)
type Client struct {
ci ClientImpl
}
func NewClient(cl ClientImpl) *Client {
return &Client{cl}
}
func (cl Client) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (*Torrent, error) {
t, err := cl.ci.OpenTorrent(info, infoHash)
return &Torrent{t}, err
}
type Torrent struct {
TorrentImpl
}
func (t Torrent) Piece(p metainfo.Piece) Piece {
return Piece{t.TorrentImpl.Piece(p), p}
}
type Piece struct {
PieceImpl
mip metainfo.Piece
}
func (p Piece) WriteAt(b []byte, off int64) (n int, err error) {
if p.GetIsComplete() {
err = errors.New("piece completed")
return
}
if off+int64(len(b)) > p.mip.Length() {
panic("write overflows piece")
}
missinggo.LimitLen(&b, p.mip.Length()-off)
return p.PieceImpl.WriteAt(b, off)
}
func (p Piece) ReadAt(b []byte, off int64) (n int, err error) {
if off < 0 {
err = os.ErrInvalid
return
}
if off >= p.mip.Length() {
err = io.EOF
return
}
missinggo.LimitLen(&b, p.mip.Length()-off)
if len(b) == 0 {
return
}
n, err = p.PieceImpl.ReadAt(b, off)
if n > len(b) {
panic(n)
}
off += int64(n)
if err == io.EOF && off < p.mip.Length() {
err = io.ErrUnexpectedEOF
}
if err == nil && off >= p.mip.Length() {
err = io.EOF
}
if n == 0 && err == nil {
err = io.ErrUnexpectedEOF
}
if off < p.mip.Length() && err != nil {
p.MarkNotComplete()
}
return
}