1 // Copyright 2019 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Utility file to provide a fake clock object representing current time, and a timerfd driven by 6 // that time. 7 8 use std::os::unix::io::AsRawFd; 9 use std::time::{Duration, Instant}; 10 11 use crate::EventFd; 12 13 #[derive(Debug, Copy, Clone)] 14 pub struct Clock(Instant); 15 impl Clock { new() -> Self16 pub fn new() -> Self { 17 Clock(Instant::now()) 18 } 19 now(&self) -> Self20 pub fn now(&self) -> Self { 21 Clock(Instant::now()) 22 } 23 duration_since(&self, earlier: &Self) -> Duration24 pub fn duration_since(&self, earlier: &Self) -> Duration { 25 self.0.duration_since(earlier.0) 26 } 27 } 28 29 impl Default for Clock { default() -> Self30 fn default() -> Self { 31 Self::new() 32 } 33 } 34 35 const NS_PER_SEC: u64 = 1_000_000_000; 36 /// A fake clock that can be used in tests to give exact control over the time. 37 /// For a code example, see the tests in sys_util/src/timerfd.rs. 38 #[derive(Debug)] 39 pub struct FakeClock { 40 ns_since_epoch: u64, 41 deadlines: Vec<(u64, EventFd)>, 42 } 43 44 impl FakeClock { new() -> Self45 pub fn new() -> Self { 46 FakeClock { 47 ns_since_epoch: 1_547_163_599 * NS_PER_SEC, 48 deadlines: Vec::new(), 49 } 50 } 51 52 /// Get the current time, according to this clock. now(&self) -> Self53 pub fn now(&self) -> Self { 54 FakeClock { 55 ns_since_epoch: self.ns_since_epoch, 56 deadlines: Vec::new(), 57 } 58 } 59 60 /// Get the current time in ns, according to this clock. nanos(&self) -> u6461 pub fn nanos(&self) -> u64 { 62 self.ns_since_epoch 63 } 64 65 /// Get the duration since |earlier|, assuming that earlier < self. duration_since(&self, earlier: &Self) -> Duration66 pub fn duration_since(&self, earlier: &Self) -> Duration { 67 let ns_diff = self.ns_since_epoch - earlier.ns_since_epoch; 68 Duration::new(ns_diff / NS_PER_SEC, (ns_diff % NS_PER_SEC) as u32) 69 } 70 71 /// Register the event fd for a notification when self's time is |deadline_ns|. 72 /// Drop any existing events registered to the same raw fd. add_event_fd(&mut self, deadline_ns: u64, fd: EventFd)73 pub fn add_event_fd(&mut self, deadline_ns: u64, fd: EventFd) { 74 self.deadlines 75 .retain(|(_, old_fd)| fd.as_raw_fd() != old_fd.as_raw_fd()); 76 self.deadlines.push((deadline_ns, fd)); 77 } 78 add_ns(&mut self, ns: u64)79 pub fn add_ns(&mut self, ns: u64) { 80 self.ns_since_epoch += ns; 81 let time = self.ns_since_epoch; 82 self.deadlines.retain(|(ns, fd)| { 83 let expired = *ns <= time; 84 if expired { 85 fd.write(1).unwrap(); 86 } 87 !expired 88 }); 89 } 90 } 91 92 impl Default for FakeClock { default() -> Self93 fn default() -> Self { 94 Self::new() 95 } 96 } 97