| // Copyright 2019 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Utility file to provide a fake clock object representing current time, and a timerfd driven by |
| // that time. |
| |
| use std::os::unix::io::AsRawFd; |
| use std::time::{Duration, Instant}; |
| |
| use crate::EventFd; |
| |
| #[derive(Debug, Copy, Clone)] |
| pub struct Clock(Instant); |
| impl Clock { |
| pub fn new() -> Self { |
| Clock(Instant::now()) |
| } |
| |
| pub fn now(&self) -> Self { |
| Clock(Instant::now()) |
| } |
| |
| pub fn duration_since(&self, earlier: &Self) -> Duration { |
| self.0.duration_since(earlier.0) |
| } |
| |
| pub fn elapsed(&self) -> Duration { |
| self.0.elapsed() |
| } |
| |
| pub fn checked_sub(&self, duration: Duration) -> Option<Self> { |
| Some(Clock(self.0.checked_sub(duration)?)) |
| } |
| } |
| |
| impl Default for Clock { |
| fn default() -> Self { |
| Self::new() |
| } |
| } |
| |
| const NS_PER_SEC: u64 = 1_000_000_000; |
| /// A fake clock that can be used in tests to give exact control over the time. |
| /// For a code example, see the tests in sys_util/src/timerfd.rs. |
| #[derive(Debug)] |
| pub struct FakeClock { |
| ns_since_epoch: u64, |
| deadlines: Vec<(u64, EventFd)>, |
| } |
| |
| impl FakeClock { |
| pub fn new() -> Self { |
| FakeClock { |
| ns_since_epoch: 1_547_163_599 * NS_PER_SEC, |
| deadlines: Vec::new(), |
| } |
| } |
| |
| /// Get the current time, according to this clock. |
| pub fn now(&self) -> Self { |
| FakeClock { |
| ns_since_epoch: self.ns_since_epoch, |
| deadlines: Vec::new(), |
| } |
| } |
| |
| /// Get the current time in ns, according to this clock. |
| pub fn nanos(&self) -> u64 { |
| self.ns_since_epoch |
| } |
| |
| /// Get the duration since |earlier|, assuming that earlier < self. |
| pub fn duration_since(&self, earlier: &Self) -> Duration { |
| let ns_diff = self.ns_since_epoch - earlier.ns_since_epoch; |
| Duration::new(ns_diff / NS_PER_SEC, (ns_diff % NS_PER_SEC) as u32) |
| } |
| |
| /// Get the time that has elapsed since this clock was made. Always returns 0 on a FakeClock. |
| pub fn elapsed(&self) -> Duration { |
| self.now().duration_since(self) |
| } |
| |
| pub fn checked_sub(&self, duration: Duration) -> Option<Self> { |
| Some(FakeClock { |
| ns_since_epoch: self |
| .ns_since_epoch |
| .checked_sub(duration.as_nanos() as u64)?, |
| deadlines: Vec::new(), |
| }) |
| } |
| |
| /// Register the event fd for a notification when self's time is |deadline_ns|. |
| /// Drop any existing events registered to the same raw fd. |
| pub fn add_event_fd(&mut self, deadline_ns: u64, fd: EventFd) { |
| self.deadlines |
| .retain(|(_, old_fd)| fd.as_raw_fd() != old_fd.as_raw_fd()); |
| self.deadlines.push((deadline_ns, fd)); |
| } |
| |
| pub fn add_ns(&mut self, ns: u64) { |
| self.ns_since_epoch += ns; |
| let time = self.ns_since_epoch; |
| self.deadlines.retain(|(ns, fd)| { |
| let expired = *ns <= time; |
| if expired { |
| fd.write(1).unwrap(); |
| } |
| !expired |
| }); |
| } |
| } |
| |
| impl Default for FakeClock { |
| fn default() -> Self { |
| Self::new() |
| } |
| } |