124 lines
2.5 KiB
Go
124 lines
2.5 KiB
Go
package storage
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import (
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"fmt"
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"io"
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"os"
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"path/filepath"
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"github.com/anacrolix/missinggo"
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"github.com/edsrzf/mmap-go"
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"github.com/anacrolix/torrent/metainfo"
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"github.com/anacrolix/torrent/mmap_span"
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)
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type mmapStorage struct {
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baseDir string
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}
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func NewMMap(baseDir string) Client {
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return &mmapStorage{
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baseDir: baseDir,
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}
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}
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func (s *mmapStorage) OpenTorrent(info *metainfo.InfoEx) (t Torrent, err error) {
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span, err := mMapTorrent(&info.Info, s.baseDir)
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t = &mmapTorrentStorage{
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span: span,
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pc: pieceCompletionForDir(s.baseDir),
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}
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return
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}
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type mmapTorrentStorage struct {
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span mmap_span.MMapSpan
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pc pieceCompletion
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}
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func (ts *mmapTorrentStorage) Piece(p metainfo.Piece) Piece {
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return mmapStoragePiece{
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pc: ts.pc,
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p: p,
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ReaderAt: io.NewSectionReader(ts.span, p.Offset(), p.Length()),
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WriterAt: missinggo.NewSectionWriter(ts.span, p.Offset(), p.Length()),
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}
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}
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func (ts *mmapTorrentStorage) Close() error {
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ts.pc.Close()
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return ts.span.Close()
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}
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type mmapStoragePiece struct {
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pc pieceCompletion
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p metainfo.Piece
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io.ReaderAt
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io.WriterAt
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}
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func (sp mmapStoragePiece) GetIsComplete() bool {
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return sp.pc.Get(sp.p)
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}
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func (sp mmapStoragePiece) MarkComplete() error {
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sp.pc.Set(sp.p, true)
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return nil
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}
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func mMapTorrent(md *metainfo.Info, location string) (mms mmap_span.MMapSpan, err error) {
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defer func() {
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if err != nil {
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mms.Close()
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}
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}()
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for _, miFile := range md.UpvertedFiles() {
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fileName := filepath.Join(append([]string{location, md.Name}, miFile.Path...)...)
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err = os.MkdirAll(filepath.Dir(fileName), 0777)
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if err != nil {
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err = fmt.Errorf("error creating data directory %q: %s", filepath.Dir(fileName), err)
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return
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}
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var file *os.File
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file, err = os.OpenFile(fileName, os.O_CREATE|os.O_RDWR, 0666)
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if err != nil {
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return
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}
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func() {
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defer file.Close()
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var fi os.FileInfo
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fi, err = file.Stat()
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if err != nil {
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return
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}
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if fi.Size() < miFile.Length {
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err = file.Truncate(miFile.Length)
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if err != nil {
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return
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}
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}
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if miFile.Length == 0 {
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// Can't mmap() regions with length 0.
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return
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}
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var mMap mmap.MMap
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mMap, err = mmap.MapRegion(file,
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int(miFile.Length), // Probably not great on <64 bit systems.
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mmap.RDWR, 0, 0)
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if err != nil {
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err = fmt.Errorf("error mapping file %q, length %d: %s", file.Name(), miFile.Length, err)
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return
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}
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if int64(len(mMap)) != miFile.Length {
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panic("mmap has wrong length")
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}
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mms.Append(mMap)
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}()
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if err != nil {
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return
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}
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}
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return
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}
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