fs/file_handle.go

   1 package torrentfs
   2
   3 import (
   4         "context"
   5         "io"
   6
   7         "bazil.org/fuse"
   8         "bazil.org/fuse/fs"
   9         "github.com/anacrolix/missinggo"
  10         "github.com/anacrolix/torrent"
  11 )
  12
  13 type fileHandle struct {
  14         fn fileNode
  15         r  torrent.Reader
  16 }
  17
  18 var _ interface {
  19         fs.HandleReader
  20         fs.HandleReleaser
  21 } = fileHandle{}
  22
  23 func (me fileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
  24         torrentfsReadRequests.Add(1)
  25         if req.Dir {
  26                 panic("read on directory")
  27         }
  28         pos, err := me.r.Seek(req.Offset, io.SeekStart)
  29         if err != nil {
  30                 panic(err)
  31         }
  32         if pos != req.Offset {
  33                 panic("seek failed")
  34         }
  35         resp.Data = resp.Data[:req.Size]
  36         readDone := make(chan struct{})
  37         ctx, cancel := context.WithCancel(ctx)
  38         var readErr error
  39         go func() {
  40                 defer close(readDone)
  41                 me.fn.FS.mu.Lock()
  42                 me.fn.FS.blockedReads++
  43                 me.fn.FS.event.Broadcast()
  44                 me.fn.FS.mu.Unlock()
  45                 var n int
  46                 r := missinggo.ContextedReader{me.r, ctx}
  47                 n, readErr = r.Read(resp.Data)
  48                 if readErr == io.EOF {
  49                         readErr = nil
  50                 }
  51                 resp.Data = resp.Data[:n]
  52         }()
  53         defer func() {
  54                 <-readDone
  55                 me.fn.FS.mu.Lock()
  56                 me.fn.FS.blockedReads--
  57                 me.fn.FS.event.Broadcast()
  58                 me.fn.FS.mu.Unlock()
  59         }()
  60         defer cancel()
  61
  62         select {
  63         case <-readDone:
  64                 return readErr
  65         case <-me.fn.FS.destroyed:
  66                 return fuse.EIO
  67         case <-ctx.Done():
  68                 return fuse.EINTR
  69         }
  70 }
  71
  72 func (me fileHandle) Release(context.Context, *fuse.ReleaseRequest) error {
  73         return me.r.Close()
  74 }