FedP2P/storage/wrappers.go

84 lines
1.5 KiB
Go

package storage
import (
"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)
if err != nil {
return nil, err
}
return &Torrent{t}, nil
}
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) {
// Callers should not be writing to completed pieces, but it's too
// expensive to be checking this on every single write using uncached
// completions.
// c := p.Completion()
// if c.Ok && c.Complete {
// err = errors.New("piece already completed")
// return
// }
if off+int64(len(b)) > p.mip.Length() {
panic("write overflows piece")
}
b = 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
}
b = 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)
}
if n == 0 && err == nil {
panic("io.Copy will get stuck")
}
off += int64(n)
if off < p.mip.Length() && err != nil {
p.MarkNotComplete()
}
return
}