FedP2P/fs/file_handle.go

85 lines
1.9 KiB
Go

package torrentfs
import (
"context"
"io"
"bazil.org/fuse"
"bazil.org/fuse/fs"
"github.com/anacrolix/missinggo/v2"
"github.com/anacrolix/torrent"
)
type fileHandle struct {
fn fileNode
r torrent.Reader
}
var _ interface {
fs.HandleReader
fs.HandleReleaser
} = fileHandle{}
func (me fileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
torrentfsReadRequests.Add(1)
if req.Dir {
panic("read on directory")
}
r := me.r
pos, err := r.Seek(req.Offset, io.SeekStart)
if err != nil {
panic(err)
}
if pos != req.Offset {
panic("seek failed")
}
resp.Data = resp.Data[:req.Size]
readDone := make(chan struct{})
ctx, cancel := context.WithCancel(ctx)
var readErr error
go func() {
defer close(readDone)
me.fn.FS.mu.Lock()
me.fn.FS.blockedReads++
me.fn.FS.event.Broadcast()
me.fn.FS.mu.Unlock()
var n int
r := missinggo.ContextedReader{r, ctx}
//log.Printf("reading %v bytes at %v", len(resp.Data), req.Offset)
if true {
// A user reported on that on freebsd 12.2, the system requires that reads are
// completely filled. Their system only asks for 64KiB at a time. I've seen systems that
// can demand up to 16MiB at a time, so this gets tricky. For now, I'll restore the old
// behaviour from before 2a7352a, which nobody reported problems with.
n, readErr = io.ReadFull(r, resp.Data)
} else {
n, readErr = r.Read(resp.Data)
if readErr == io.EOF {
readErr = nil
}
}
resp.Data = resp.Data[:n]
}()
defer func() {
<-readDone
me.fn.FS.mu.Lock()
me.fn.FS.blockedReads--
me.fn.FS.event.Broadcast()
me.fn.FS.mu.Unlock()
}()
defer cancel()
select {
case <-readDone:
return readErr
case <-me.fn.FS.destroyed:
return fuse.EIO
case <-ctx.Done():
return fuse.EINTR
}
}
func (me fileHandle) Release(context.Context, *fuse.ReleaseRequest) error {
return me.r.Close()
}