FedP2P/storage/piece_resource.go

159 lines
3.2 KiB
Go

package storage
import (
"bytes"
"io"
"path"
"sort"
"strconv"
"github.com/anacrolix/missinggo/v2/resource"
"github.com/anacrolix/torrent/metainfo"
)
type piecePerResource struct {
p resource.Provider
}
func NewResourcePieces(p resource.Provider) ClientImpl {
return &piecePerResource{
p: p,
}
}
type piecePerResourceTorrentImpl struct {
piecePerResource
}
func (piecePerResourceTorrentImpl) Close() error {
return nil
}
func (s piecePerResource) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (TorrentImpl, error) {
return piecePerResourceTorrentImpl{s}, nil
}
func (s piecePerResource) Piece(p metainfo.Piece) PieceImpl {
return piecePerResourcePiece{
mp: p,
rp: s.p,
}
}
type piecePerResourcePiece struct {
mp metainfo.Piece
rp resource.Provider
}
func (s piecePerResourcePiece) Completion() Completion {
fi, err := s.completed().Stat()
return Completion{
Complete: err == nil && fi.Size() == s.mp.Length(),
Ok: true,
}
}
func (s piecePerResourcePiece) MarkComplete() error {
incompleteChunks := s.getChunks()
err := s.completed().Put(io.NewSectionReader(incompleteChunks, 0, s.mp.Length()))
if err == nil {
for _, c := range incompleteChunks {
c.instance.Delete()
}
}
return err
}
func (s piecePerResourcePiece) MarkNotComplete() error {
return s.completed().Delete()
}
func (s piecePerResourcePiece) ReadAt(b []byte, off int64) (int, error) {
if s.Completion().Complete {
return s.completed().ReadAt(b, off)
}
return s.getChunks().ReadAt(b, off)
}
func (s piecePerResourcePiece) WriteAt(b []byte, off int64) (n int, err error) {
i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), strconv.FormatInt(off, 10)))
if err != nil {
panic(err)
}
r := bytes.NewReader(b)
err = i.Put(r)
n = len(b) - r.Len()
return
}
type chunk struct {
offset int64
instance resource.Instance
}
type chunks []chunk
func (me chunks) ReadAt(b []byte, off int64) (int, error) {
for {
if len(me) == 0 {
return 0, io.EOF
}
if me[0].offset <= off {
break
}
me = me[1:]
}
n, err := me[0].instance.ReadAt(b, off-me[0].offset)
if n == len(b) {
return n, nil
}
if err == nil || err == io.EOF {
n_, err := me[1:].ReadAt(b[n:], off+int64(n))
return n + n_, err
}
return n, err
}
func (s piecePerResourcePiece) getChunks() (chunks chunks) {
names, err := s.incompleteDir().Readdirnames()
if err != nil {
return
}
for _, n := range names {
offset, err := strconv.ParseInt(n, 10, 64)
if err != nil {
panic(err)
}
i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), n))
if err != nil {
panic(err)
}
chunks = append(chunks, chunk{offset, i})
}
sort.Slice(chunks, func(i, j int) bool {
return chunks[i].offset < chunks[j].offset
})
return
}
func (s piecePerResourcePiece) completed() resource.Instance {
i, err := s.rp.NewInstance(path.Join("completed", s.mp.Hash().HexString()))
if err != nil {
panic(err)
}
return i
}
func (s piecePerResourcePiece) incompleteDirPath() string {
return path.Join("incompleted", s.mp.Hash().HexString())
}
func (s piecePerResourcePiece) incompleteDir() resource.DirInstance {
i, err := s.rp.NewInstance(s.incompleteDirPath())
if err != nil {
panic(err)
}
return i.(resource.DirInstance)
}