Method poll

crates/stdlib/src/select.rs:490–526

(
                &self,
                timeout: OptionalArg<TimeoutArg<true>>,
                vm: &VirtualMachine,
            )

            #[pymethod]
            fn poll(
                &self,
                timeout: OptionalArg<TimeoutArg<true>>,
                vm: &VirtualMachine,
            ) -> PyResult<Vec<PyObjectRef>> {
                let mut fds = self.fds.lock();
                let TimeoutArg(timeout) = timeout.unwrap_or_default();
                let timeout_ms = match timeout {
                    Some(d) => i32::try_from(d.as_millis())
                        .map_err(|_| vm.new_overflow_error("value out of range"))?,
                    None => -1i32,
                };
                let deadline = timeout.map(|d| Instant::now() + d);
                let mut poll_timeout = timeout_ms;
                loop {
                    let res = vm.allow_threads(|| unsafe {
                        libc::poll(fds.as_mut_ptr(), fds.len() as _, poll_timeout)
                    });
                    match nix::Error::result(res) {
                        Ok(_) => break,
                        Err(nix::Error::EINTR) => vm.check_signals()?,
                        Err(e) => return Err(e.into_pyexception(vm)),
                    }
                    if let Some(d) = deadline {
                        if let Some(remaining) = d.checked_duration_since(Instant::now()) {
                            poll_timeout = remaining.as_millis() as i32;
                        } else {
                            break;
                        }
                    }
                }
                Ok(fds
                    .iter()
                    .filter(|pfd| pfd.revents != 0)
                    .map(|pfd| (pfd.fd, pfd.revents & 0xfff).to_pyobject(vm))
                    .collect())
            }
        }
    }