// transferDetachmentConn transfers as much of a detachment as possible on a
// single connection. It calls sendStatus repeatedly with the current state of
// the transfer and watches killChan for an abort signal. It returns an error
// and an indication of whether the error is fatal. If not fatatl then another
// connection can be attempted in order to resume the transfer.
func (c *client) transferDetachmentConn(sendStatus func(s string, done, total int64), conn *transport.Conn, transfer detachmentTransfer, killChan chan bool) (err error, fatal bool) {
defer conn.Close()
// transferred is the number of bytes that *this connection* has transferred.
// total is the full length of the file.
var startingOffset, transferred, total int64
sendStatus("Requesting transfer", 0, 0)
if err := conn.WriteProto(transfer.Request()); err != nil {
return fmt.Errorf("failed to write request: %s", err), false
}
reply := new(pond.Reply)
if err := conn.ReadProto(reply); err != nil {
return fmt.Errorf("failed to read reply: %s", err), false
}
if reply.Status != nil && *reply.Status == pond.Reply_RESUME_PAST_END_OF_FILE {
return nil, false
}
if err := replyToError(reply); err != nil {
if reply.GetStatus() == pond.Reply_OVER_QUOTA {
return fmt.Errorf("server reports that the upload would exceed allowed quota"), true
}
return fmt.Errorf("request failed: %s", err), false
}
var file *os.File
var isUpload, isComplete bool
if file, isUpload, startingOffset, total, isComplete, err = transfer.ProcessReply(reply); err != nil {
return fmt.Errorf("request failed: %s", err), false
}
if isComplete {
return nil, false
}
todo := total - startingOffset
var in io.Reader
var out io.Writer
if isUpload {
out = conn
in = file
} else {
out = file
in = conn
}
buf := make([]byte, 16*1024)
var lastUpdate time.Time
for transferred < todo {
select {
case <-killChan:
return backgroundCanceledError, true
default:
break
}
conn.SetDeadline(time.Now().Add(30 * time.Second))
n, err := in.Read(buf)
if err != nil {
if isUpload {
return fmt.Errorf("failed to read from disk: %s", err), true
}
return err, false
}
n, err = out.Write(buf[:n])
if err != nil {
if !isUpload {
return fmt.Errorf("failed to write to disk: %s", err), true
}
return err, false
}
transferred += int64(n)
if transferred > todo {
return errors.New("transferred more than the expected amount"), true
}
now := time.Now()
if lastUpdate.IsZero() || now.Sub(lastUpdate) > 10*time.Millisecond {
lastUpdate = now
sendStatus("", startingOffset+transferred, total)
}
}
sendStatus("", startingOffset+transferred, total)
if transferred < todo {
return errors.New("incomplete transfer"), false
}
if !transfer.Complete(conn) {
return errors.New("didn't receive confirmation from server"), false
}
return nil, false
}
