// completeRequest looks at iodata to see if a request is pending. If so, it waits for it to either complete or to
// abort due to hitting the specified deadline. Deadline may be set to nil to wait forever. If no request is pending,
// the content of iodata is returned.
func (c *PipeConn) completeRequest(data iodata, deadline *time.Time, overlapped *syscall.Overlapped) (int, error) {
if data.err == error_io_incomplete || data.err == syscall.ERROR_IO_PENDING {
var timer <-chan time.Time
if deadline != nil {
if timeDiff := deadline.Sub(time.Now()); timeDiff > 0 {
timer = time.After(timeDiff)
}
}
done := make(chan iodata)
go func() {
n, err := waitForCompletion(c.handle, overlapped)
done <- iodata{n, err}
}()
select {
case data = <-done:
case <-timer:
syscall.CancelIoEx(c.handle, overlapped)
data = iodata{0, timeout(c.addr.String())}
}
}
// Windows will produce ERROR_BROKEN_PIPE upon closing
// a handle on the other end of a connection. Go RPC
// expects an io.EOF error in this case.
if data.err == syscall.ERROR_BROKEN_PIPE {
data.err = io.EOF
}
return int(data.n), data.err
}
// ExecIO executes a single IO operation oi. It submits and cancels
// IO in the current thread for systems where Windows CancelIoEx API
// is available. Alternatively, it passes the request onto
// a special goroutine and waits for completion or cancels request.
// deadline is unix nanos.
func (s *ioSrv) ExecIO(oi anOpIface, deadline int64) (int, error) {
var err error
o := oi.Op()
// Calculate timeout delta.
var delta int64
if deadline != 0 {
delta = deadline - time.Now().UnixNano()
if delta <= 0 {
return 0, &OpError{oi.Name(), o.fd.net, o.fd.laddr, errTimeout}
}
}
// Start IO.
if canCancelIO {
err = oi.Submit()
} else {
// Send request to a special dedicated thread,
// so it can stop the IO with CancelIO later.
s.submchan <- oi
err = <-o.errnoc
}
switch err {
case nil:
// IO completed immediately, but we need to get our completion message anyway.
case syscall.ERROR_IO_PENDING:
// IO started, and we have to wait for its completion.
err = nil
default:
return 0, &OpError{oi.Name(), o.fd.net, o.fd.laddr, err}
}
// Setup timer, if deadline is given.
var timer <-chan time.Time
if delta > 0 {
t := time.NewTimer(time.Duration(delta) * time.Nanosecond)
defer t.Stop()
timer = t.C
}
// Wait for our request to complete.
var r ioResult
var cancelled, timeout bool
select {
case r = <-o.resultc:
case <-timer:
cancelled = true
timeout = true
case <-o.fd.closec:
cancelled = true
}
if cancelled {
// Cancel it.
if canCancelIO {
err := syscall.CancelIoEx(syscall.Handle(o.Op().fd.sysfd), &o.o)
// Assuming ERROR_NOT_FOUND is returned, if IO is completed.
if err != nil && err != syscall.ERROR_NOT_FOUND {
// TODO(brainman): maybe do something else, but panic.
panic(err)
}
} else {
s.canchan <- oi
<-o.errnoc
}
// Wait for IO to be canceled or complete successfully.
r = <-o.resultc
if r.err == syscall.ERROR_OPERATION_ABORTED { // IO Canceled
if timeout {
r.err = errTimeout
} else {
r.err = errClosing
}
}
}
if r.err != nil {
err = &OpError{oi.Name(), o.fd.net, o.fd.laddr, r.err}
}
return int(r.qty), err
}
// ExecIO executes a single IO operation o. It submits and cancels
// IO in the current thread for systems where Windows CancelIoEx API
// is available. Alternatively, it passes the request onto
// runtime netpoll and waits for completion or cancels request.
func (s *ioSrv) ExecIO(o *operation, name string, submit func(o *operation) error) (int, error) {
fd := o.fd
// Notify runtime netpoll about starting IO.
err := fd.pd.Prepare(int(o.mode))
if err != nil {
return 0, &OpError{name, fd.net, fd.laddr, err}
}
// Start IO.
if canCancelIO {
err = submit(o)
} else {
// Send request to a special dedicated thread,
// so it can stop the IO with CancelIO later.
s.req <- ioSrvReq{o, submit}
err = <-o.errc
}
switch err {
case nil:
// IO completed immediately
if o.fd.skipSyncNotif {
// No completion message will follow, so return immediately.
return int(o.qty), nil
}
// Need to get our completion message anyway.
case syscall.ERROR_IO_PENDING:
// IO started, and we have to wait for its completion.
err = nil
default:
return 0, &OpError{name, fd.net, fd.laddr, err}
}
// Wait for our request to complete.
err = fd.pd.Wait(int(o.mode))
if err == nil {
// All is good. Extract our IO results and return.
if o.errno != 0 {
err = syscall.Errno(o.errno)
return 0, &OpError{name, fd.net, fd.laddr, err}
}
return int(o.qty), nil
}
// IO is interrupted by "close" or "timeout"
netpollErr := err
switch netpollErr {
case errClosing, errTimeout:
// will deal with those.
default:
panic("net: unexpected runtime.netpoll error: " + netpollErr.Error())
}
// Cancel our request.
if canCancelIO {
err := syscall.CancelIoEx(fd.sysfd, &o.o)
// Assuming ERROR_NOT_FOUND is returned, if IO is completed.
if err != nil && err != syscall.ERROR_NOT_FOUND {
// TODO(brainman): maybe do something else, but panic.
panic(err)
}
} else {
s.req <- ioSrvReq{o, nil}
<-o.errc
}
// Wait for cancellation to complete.
fd.pd.WaitCanceled(int(o.mode))
if o.errno != 0 {
err = syscall.Errno(o.errno)
if err == syscall.ERROR_OPERATION_ABORTED { // IO Canceled
err = netpollErr
}
return 0, &OpError{name, fd.net, fd.laddr, err}
}
// We issued cancellation request. But, it seems, IO operation succeeded
// before cancellation request run. We need to treat IO operation as
// succeeded (the bytes are actually sent/recv from network).
return int(o.qty), nil
}