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mirror of synced 2025-02-24 06:38:14 +00:00
torrent/storage/wrappers.go
Matt Joiner 1e919dd6b1 Rework storage interfaces to make them simpler to implement
This allows lots of behaviour to be baked into the new Client, Torrent and Piece wrappers, rather than duplicating (badly) them in all the backend implementations.
2016-09-02 15:10:57 +10:00

83 lines
1.4 KiB
Go

package storage
import (
"errors"
"io"
"os"
"github.com/anacrolix/missinggo"
"github.com/anacrolix/torrent/metainfo"
)
type Client struct {
ClientImpl
}
func NewClient(cl ClientImpl) *Client {
return &Client{cl}
}
func (cl Client) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (*Torrent, error) {
t, err := cl.ClientImpl.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
}