Function discardInputAsync

src/cmd/utils.go:176–261

(ctx context.Context)

}

func discardInputAsync(ctx context.Context) (<-chan int, <-chan error) {
	retValCh := make(chan int, 1)
	errCh := make(chan error, 1)

	done := ctx.Done()
	eventFD := -1
	if done != nil {
		fd, err := unix.Eventfd(0, unix.EFD_CLOEXEC|unix.EFD_NONBLOCK)
		if err != nil {
			errCh <- fmt.Errorf("eventfd(2) failed: %w", err)
			return retValCh, errCh
		}

		eventFD = fd
	}

	go func() {
		var total int

		for {
			pollFn := func(errPoll error, pollFDs []unix.PollFd) error {
				if len(pollFDs) != 1 {
					panic("unexpected number of file descriptors")
				}

				if errPoll != nil && !errors.Is(errPoll, context.Canceled) {
					return errPoll
				}

				if pollFDs[0].Revents&unix.POLLIN != 0 {
					logrus.Debug("Returned from /dev/stdin: POLLIN")

					buffer := make([]byte, bytes.MinRead)
					n, err := os.Stdin.Read(buffer)
					total += n

					if errPoll != nil {
						return errPoll
					} else if err != nil {
						return err
					}

					return nil
				}

				if pollFDs[0].Revents&unix.POLLHUP != 0 {
					logrus.Debug("Returned from /dev/stdin: POLLHUP")

					if errPoll != nil {
						return errPoll
					}

					return errHUP
				}

				if pollFDs[0].Revents&unix.POLLNVAL != 0 {
					logrus.Debug("Returned from /dev/stdin: POLLNVAL")