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.
31 func NewResourcePieces(p PieceProvider) ClientImpl {
32 return NewResourcePiecesOpts(p, ResourcePiecesOpts{})
35 func NewResourcePiecesOpts(p PieceProvider, opts ResourcePiecesOpts) ClientImpl {
36 return &piecePerResource{
42 type piecePerResourceTorrentImpl struct {
47 func (piecePerResourceTorrentImpl) Close() error {
51 func (s piecePerResource) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (TorrentImpl, error) {
52 return piecePerResourceTorrentImpl{
54 make([]sync.RWMutex, info.NumPieces()),
58 func (s piecePerResourceTorrentImpl) Piece(p metainfo.Piece) PieceImpl {
59 return piecePerResourcePiece{
61 piecePerResource: s.piecePerResource,
62 mu: &s.locks[p.Index()],
66 type PieceProvider interface {
70 type ConsecutiveChunkReader interface {
71 ReadConsecutiveChunks(prefix string) (io.ReadCloser, error)
74 type piecePerResourcePiece struct {
77 // This protects operations that move complete/incomplete pieces around, which can trigger read
78 // errors that may cause callers to do more drastic things.
82 var _ io.WriterTo = piecePerResourcePiece{}
84 func (s piecePerResourcePiece) WriteTo(w io.Writer) (int64, error) {
87 if s.mustIsComplete() {
88 r, err := s.completed().Get()
90 return 0, fmt.Errorf("getting complete instance: %w", err)
95 if ccr, ok := s.rp.(ConsecutiveChunkReader); ok {
96 return s.writeConsecutiveIncompleteChunks(ccr, w)
98 return io.Copy(w, io.NewSectionReader(s, 0, s.mp.Length()))
101 func (s piecePerResourcePiece) writeConsecutiveIncompleteChunks(ccw ConsecutiveChunkReader, w io.Writer) (int64, error) {
102 r, err := ccw.ReadConsecutiveChunks(s.incompleteDirPath() + "/")
110 // Returns if the piece is complete. Ok should be true, because we are the definitive source of
112 func (s piecePerResourcePiece) mustIsComplete() bool {
113 completion := s.Completion()
115 panic("must know complete definitively")
117 return completion.Complete
120 func (s piecePerResourcePiece) Completion() Completion {
123 fi, err := s.completed().Stat()
125 Complete: err == nil && fi.Size() == s.mp.Length(),
130 type SizedPutter interface {
131 PutSized(io.Reader, int64) error
134 func (s piecePerResourcePiece) MarkComplete() error {
137 incompleteChunks := s.getChunks()
138 r, err := func() (io.ReadCloser, error) {
139 if ccr, ok := s.rp.(ConsecutiveChunkReader); ok {
140 return ccr.ReadConsecutiveChunks(s.incompleteDirPath() + "/")
142 return ioutil.NopCloser(io.NewSectionReader(incompleteChunks, 0, s.mp.Length())), nil
145 return fmt.Errorf("getting incomplete chunks reader: %w", err)
148 completedInstance := s.completed()
150 if sp, ok := completedInstance.(SizedPutter); ok && !s.opts.NoSizedPuts {
151 return sp.PutSized(r, s.mp.Length())
153 return completedInstance.Put(r)
156 if err == nil && !s.opts.LeaveIncompleteChunks {
157 // I think we do this synchronously here since we don't want callers to act on the completed
158 // piece if we're concurrently still deleting chunks. The caller may decide to start
159 // downloading chunks again and won't expect us to delete them. It seems to be much faster
160 // to let the resource provider do this if possible.
161 var wg sync.WaitGroup
162 for _, c := range incompleteChunks {
174 func (s piecePerResourcePiece) MarkNotComplete() error {
177 return s.completed().Delete()
180 func (s piecePerResourcePiece) ReadAt(b []byte, off int64) (int, error) {
183 if s.mustIsComplete() {
184 return s.completed().ReadAt(b, off)
186 return s.getChunks().ReadAt(b, off)
189 func (s piecePerResourcePiece) WriteAt(b []byte, off int64) (n int, err error) {
192 i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), strconv.FormatInt(off, 10)))
196 r := bytes.NewReader(b)
197 if sp, ok := i.(SizedPutter); ok {
198 err = sp.PutSized(r, r.Size())
208 instance resource.Instance
213 func (me chunks) ReadAt(b []byte, off int64) (int, error) {
218 if me[0].offset <= off {
223 n, err := me[0].instance.ReadAt(b, off-me[0].offset)
227 if err == nil || err == io.EOF {
228 n_, err := me[1:].ReadAt(b[n:], off+int64(n))
234 func (s piecePerResourcePiece) getChunks() (chunks chunks) {
235 names, err := s.incompleteDir().Readdirnames()
239 for _, n := range names {
240 offset, err := strconv.ParseInt(n, 10, 64)
244 i, err := s.rp.NewInstance(path.Join(s.incompleteDirPath(), n))
248 chunks = append(chunks, chunk{offset, i})
250 sort.Slice(chunks, func(i, j int) bool {
251 return chunks[i].offset < chunks[j].offset
256 func (s piecePerResourcePiece) completedInstancePath() string {
257 return path.Join("completed", s.mp.Hash().HexString())
260 func (s piecePerResourcePiece) completed() resource.Instance {
261 i, err := s.rp.NewInstance(s.completedInstancePath())
268 func (s piecePerResourcePiece) incompleteDirPath() string {
269 return path.Join("incompleted", s.mp.Hash().HexString())
272 func (s piecePerResourcePiece) incompleteDir() resource.DirInstance {
273 i, err := s.rp.NewInstance(s.incompleteDirPath())
277 return i.(resource.DirInstance)