124 lines
4.0 KiB
C++
124 lines
4.0 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef TNT_UTILS_LINUX_CONDITION_H
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#define TNT_UTILS_LINUX_CONDITION_H
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#include <atomic>
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#include <chrono>
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#include <condition_variable> // for cv_status
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#include <limits>
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#include <mutex> // for unique_lock
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#include <utils/linux/Mutex.h>
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#include <time.h>
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namespace utils {
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/*
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* A very simple condition variable class that can be used as an (almost) drop-in replacement
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* for std::condition_variable (doesn't have the timed wait() though).
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* It is very low overhead as most of it is inlined.
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*/
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class Condition {
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public:
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Condition() noexcept = default;
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Condition(const Condition&) = delete;
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Condition& operator=(const Condition&) = delete;
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void notify_all() noexcept {
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pulse(std::numeric_limits<int>::max());
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}
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void notify_one() noexcept {
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pulse(1);
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}
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void notify_n(size_t n) noexcept {
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if (n > 0) pulse(n);
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}
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void wait(std::unique_lock<Mutex>& lock) noexcept {
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wait_until(lock.mutex(), false, nullptr);
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}
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template <class P>
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void wait(std::unique_lock<Mutex>& lock, P predicate) {
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while (!predicate()) {
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wait(lock);
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}
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}
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template<typename D>
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std::cv_status wait_until(std::unique_lock<Mutex>& lock,
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const std::chrono::time_point<std::chrono::steady_clock, D>& timeout_time) noexcept {
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// convert to nanoseconds
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uint64_t ns = std::chrono::duration<uint64_t, std::nano>(timeout_time.time_since_epoch()).count();
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using sec_t = decltype(timespec::tv_sec);
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using nsec_t = decltype(timespec::tv_nsec);
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timespec ts{ sec_t(ns / 1000000000), nsec_t(ns % 1000000000) };
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return wait_until(lock.mutex(), false, &ts);
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}
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template<typename D>
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std::cv_status wait_until(std::unique_lock<Mutex>& lock,
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const std::chrono::time_point<std::chrono::system_clock, D>& timeout_time) noexcept {
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// convert to nanoseconds
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uint64_t ns = std::chrono::duration<uint64_t, std::nano>(timeout_time.time_since_epoch()).count();
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using sec_t = decltype(timespec::tv_sec);
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using nsec_t = decltype(timespec::tv_nsec);
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timespec ts{ sec_t(ns / 1000000000), nsec_t(ns % 1000000000) };
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return wait_until(lock.mutex(), true, &ts);
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}
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template<typename C, typename D, typename P>
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bool wait_until(std::unique_lock<Mutex>& lock,
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const std::chrono::time_point<C, D>& timeout_time, P predicate) noexcept {
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while (!predicate()) {
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if (wait_until(lock, timeout_time) == std::cv_status::timeout) {
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return predicate();
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}
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}
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return true;
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}
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template<typename R, typename Period>
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std::cv_status wait_for(std::unique_lock<Mutex>& lock,
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const std::chrono::duration<R, Period>& rel_time) noexcept {
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return wait_until(lock, std::chrono::steady_clock::now() + rel_time);
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}
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template<typename R, typename Period, typename P>
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bool wait_for(std::unique_lock<Mutex>& lock,
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const std::chrono::duration<R, Period>& rel_time, P pred) noexcept {
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return wait_until(lock, std::chrono::steady_clock::now() + rel_time, std::move(pred));
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}
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private:
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std::atomic<uint32_t> mState = { 0 };
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void pulse(int threadCount) noexcept;
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std::cv_status wait_until(Mutex* lock,
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bool realtimeClock, timespec* ts) noexcept;
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};
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} // namespace utils
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#endif // TNT_UTILS_LINUX_CONDITION_H
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