13 "github.com/anacrolix/missinggo/v2/resource"
15 "github.com/anacrolix/torrent/metainfo"
18 type piecePerResource struct {
20 opts ResourcePiecesOpts
23 type ResourcePiecesOpts struct {
24 // After marking a piece complete, don't bother deleting its incomplete blobs.
25 LeaveIncompleteChunks bool
26 // Sized puts require being able to stream from a statement executed on another connection.
27 // Without them, we buffer the entire read and then put that.
32 func NewResourcePieces(p PieceProvider) ClientImpl {
33 return NewResourcePiecesOpts(p, ResourcePiecesOpts{})
36 func NewResourcePiecesOpts(p PieceProvider, opts ResourcePiecesOpts) ClientImpl {
37 return &piecePerResource{
43 type piecePerResourceTorrentImpl struct {
48 func (piecePerResourceTorrentImpl) Close() error {
52 func (s piecePerResource) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (TorrentImpl, error) {
53 t := piecePerResourceTorrentImpl{
55 make([]sync.RWMutex, info.NumPieces()),
57 return TorrentImpl{Piece: t.Piece, Close: t.Close}, nil
60 func (s piecePerResourceTorrentImpl) Piece(p metainfo.Piece) PieceImpl {
61 return piecePerResourcePiece{
63 piecePerResource: s.piecePerResource,
64 mu: &s.locks[p.Index()],
68 type PieceProvider interface {
72 type ConsecutiveChunkReader interface {
73 ReadConsecutiveChunks(prefix string) (io.ReadCloser, error)
76 type piecePerResourcePiece struct {
79 // This protects operations that move complete/incomplete pieces around, which can trigger read
80 // errors that may cause callers to do more drastic things.
84 var _ io.WriterTo = piecePerResourcePiece{}
86 func (s piecePerResourcePiece) WriteTo(w io.Writer) (int64, error) {
89 if s.mustIsComplete() {
90 r, err := s.completed().Get()
92 return 0, fmt.Errorf("getting complete instance: %w", err)
97 if ccr, ok := s.rp.(ConsecutiveChunkReader); ok {
98 return s.writeConsecutiveIncompleteChunks(ccr, w)
100 return io.Copy(w, io.NewSectionReader(s, 0, s.mp.Length()))
103 func (s piecePerResourcePiece) writeConsecutiveIncompleteChunks(ccw ConsecutiveChunkReader, w io.Writer) (int64, error) {
104 r, err := ccw.ReadConsecutiveChunks(s.incompleteDirPath() + "/")
112 // Returns if the piece is complete. Ok should be true, because we are the definitive source of
114 func (s piecePerResourcePiece) mustIsComplete() bool {
115 completion := s.Completion()
117 panic("must know complete definitively")
119 return completion.Complete
122 func (s piecePerResourcePiece) Completion() Completion {
125 fi, err := s.completed().Stat()
127 Complete: err == nil && fi.Size() == s.mp.Length(),
132 type SizedPutter interface {
133 PutSized(io.Reader, int64) error
136 func (s piecePerResourcePiece) MarkComplete() error {
139 incompleteChunks := s.getChunks()
140 r, err := func() (io.ReadCloser, error) {
141 if ccr, ok := s.rp.(ConsecutiveChunkReader); ok {
142 return ccr.ReadConsecutiveChunks(s.incompleteDirPath() + "/")
144 return ioutil.NopCloser(io.NewSectionReader(incompleteChunks, 0, s.mp.Length())), nil
147 return fmt.Errorf("getting incomplete chunks reader: %w", err)
150 completedInstance := s.completed()
152 if sp, ok := completedInstance.(SizedPutter); ok && !s.opts.NoSizedPuts {
153 return sp.PutSized(r, s.mp.Length())
155 return completedInstance.Put(r)
158 if err == nil && !s.opts.LeaveIncompleteChunks {
159 // I think we do this synchronously here since we don't want callers to act on the completed
160 // piece if we're concurrently still deleting chunks. The caller may decide to start
161 // downloading chunks again and won't expect us to delete them. It seems to be much faster
162 // to let the resource provider do this if possible.
163 var wg sync.WaitGroup
164 for _, c := range incompleteChunks {
176 func (s piecePerResourcePiece) MarkNotComplete() error {
179 return s.completed().Delete()
182 func (s piecePerResourcePiece) ReadAt(b []byte, off int64) (int, error) {
185 if s.mustIsComplete() {
186 return s.completed().ReadAt(b, off)
188 return s.getChunks().ReadAt(b, off)
191 func (s piecePerResourcePiece) WriteAt(b []byte, off int64) (n int, err error) {
194 i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), strconv.FormatInt(off, 10)))
198 r := bytes.NewReader(b)
199 if sp, ok := i.(SizedPutter); ok {
200 err = sp.PutSized(r, r.Size())
210 instance resource.Instance
215 func (me chunks) ReadAt(b []byte, off int64) (int, error) {
220 if me[0].offset <= off {
225 n, err := me[0].instance.ReadAt(b, off-me[0].offset)
229 if err == nil || err == io.EOF {
230 n_, err := me[1:].ReadAt(b[n:], off+int64(n))
236 func (s piecePerResourcePiece) getChunks() (chunks chunks) {
237 names, err := s.incompleteDir().Readdirnames()
241 for _, n := range names {
242 offset, err := strconv.ParseInt(n, 10, 64)
246 i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), n))
250 chunks = append(chunks, chunk{offset, i})
252 sort.Slice(chunks, func(i, j int) bool {
253 return chunks[i].offset < chunks[j].offset
258 func (s piecePerResourcePiece) completedInstancePath() string {
259 return path.Join("completed", s.mp.Hash().HexString())
262 func (s piecePerResourcePiece) completed() resource.Instance {
263 i, err := s.rp.NewInstance(s.completedInstancePath())
270 func (s piecePerResourcePiece) incompleteDirPath() string {
271 return path.Join("incompleted", s.mp.Hash().HexString())
274 func (s piecePerResourcePiece) incompleteDir() resource.DirInstance {
275 i, err := s.rp.NewInstance(s.incompleteDirPath())
279 return i.(resource.DirInstance)