func (t *traverser) readFile(sq *seq.Sequencer, fid *g9pc.NsFile, path string) {
t.printf("readFile %s", path)
sq, results := sq.Subsequencer("readFile")
go func() {
_, ok := <-results // open
if !ok {
t.printf("cannot open %s: %v", path, sq.Error())
return
}
<-results // stream
_, ok = <-results
if ok {
panic("expected closed")
}
sq.Result(seq.StringResult("readFile"), sq.Error())
}()
sq.Do(fid.File(), seq.OpenReq{g9p.OREAD})
rd := fid.SeqReadStream(sq, 20, 8192)
tot, _ := io.Copy(nullWriter{}, rd)
t.printf("%10d %s", tot, path)
sq.Do(nil, nil)
}
func (nsf *NsFile) SeqReadStream(sq *seq.Sequencer, nreqs, iounit int) io.ReadCloser {
cr := &streamReader{
c: make(chan readResult, 1),
reply: make(chan bool),
}
sq, results := sq.Subsequencer("stream reader")
buf := make([]byte, nreqs*iounit)
bufs := make(chan []byte, nreqs)
for i := 0; i < nreqs; i++ {
bufs <- buf[0:iounit]
buf = buf[iounit:]
}
buf = nil
var q safeQueue
done := make(chan bool)
// Stream requests.
go func() {
f := nsf.File()
offset := int64(0)
for {
b, ok := <-bufs
if !ok {
break
}
q.Put(b)
log.Printf("stream doer: read %v", offset)
sq.Do(f, seq.ReadReq{b, offset})
offset += int64(len(b))
}
log.Printf("stream doer: do(nil, nil)")
sq.Do(nil, nil)
done <- true
}()
// Stream replies on demand from the streamReader.
go func() {
readerClosed := false
for r := range results {
log.Printf("stream: got result %#v (chan %p)\n", r, results)
b := q.Get().([]byte)
cr.c <- readResult{b[0:r.(seq.ReadResult).Count], nil}
if !<-cr.reply {
readerClosed = true
break
}
bufs <- b
}
log.Printf("stream: closed")
// Stop as many requests as possible from being sent.
// If we implemented flush, we would flush the request now.
loop:
for {
select {
case <-bufs:
default:
break loop
}
}
close(bufs)
// Absorb and ignore any extra replies.
for r := range results {
log.Printf("stream: aborbing extra: %#v\n", r)
}
<-done
err := sq.Error()
if !readerClosed {
log.Printf("stream: sending error to reader")
if err == nil {
err = io.EOF
}
cr.c <- readResult{nil, err}
}
log.Printf("stream: yielding result, err %#v\n", err)
sq.Result(seq.StringResult("SeqReadStream"), err)
}()
return cr
}