1 // Copyright 2017 The Chromium 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 #include "time_utils.h" 6 7 #include <sys/time.h> 8 #include <sys/timerfd.h> 9 #include <time.h> 10 11 #include "logging.h" 12 13 namespace time_utils { 14 GetTimestamp()15uint64_t GetTimestamp() { 16 struct timespec ts = {}; 17 CHECK(clock_gettime(CLOCK_MONOTONIC_COARSE, &ts) == 0); 18 return ts.tv_sec * 1000 + ts.tv_nsec / 1000000ul; 19 } 20 PeriodicTimer(int interval_ms)21PeriodicTimer::PeriodicTimer(int interval_ms) : interval_ms_(interval_ms) { 22 timer_fd_ = -1; 23 } 24 ~PeriodicTimer()25PeriodicTimer::~PeriodicTimer() { 26 Stop(); 27 } 28 Start()29void PeriodicTimer::Start() { 30 Stop(); 31 timer_fd_ = timerfd_create(CLOCK_MONOTONIC, 0); 32 CHECK(timer_fd_ >= 0); 33 int sec = interval_ms_ / 1000; 34 int nsec = (interval_ms_ % 1000) * 1000000; 35 struct itimerspec ts = {}; 36 ts.it_value.tv_nsec = nsec; 37 ts.it_value.tv_sec = sec; 38 ts.it_interval.tv_nsec = nsec; 39 ts.it_interval.tv_sec = sec; 40 CHECK(timerfd_settime(timer_fd_, 0, &ts, nullptr) == 0); 41 } 42 Stop()43void PeriodicTimer::Stop() { 44 if (timer_fd_ < 0) 45 return; 46 close(timer_fd_); 47 timer_fd_ = -1; 48 } 49 Wait()50bool PeriodicTimer::Wait() { 51 if (timer_fd_ < 0) 52 return false; // Not started yet. 53 uint64_t stub = 0; 54 int res = read(timer_fd_, &stub, sizeof(stub)); 55 if (res < 0 && errno == EBADF) 56 return false; // Interrupted by Stop(). 57 CHECK(res > 0); 58 return true; 59 } 60 61 } // namespace time_utils 62