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// Copyright 2022 Huawei Cloud Computing Technology Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef INCLUDED_SRC_BUILDTOOL_SYSTEM_SYSTEM_HPP
#define INCLUDED_SRC_BUILDTOOL_SYSTEM_SYSTEM_HPP
#include <chrono>
#include "src/utils/cpp/concepts.hpp"
namespace System {
void ExitWithoutCleanup(int exit_code);
/// \brief Obtain POSIX epoch time for a given clock.
/// Clocks may have different epoch times. To obtain the POSIX epoch time
/// (1970-01-01 00:00:00 UTC) for a given clock, it must be converted.
template <class T_Clock>
static auto GetPosixEpoch() -> std::chrono::time_point<T_Clock> {
// Since C++20, the system clock's default value is the POSIX epoch time.
std::chrono::time_point<std::chrono::system_clock> sys_epoch{};
if constexpr (std::is_same_v<T_Clock, std::chrono::system_clock>) {
// No conversion necessary for the system clock.
return sys_epoch;
}
else if constexpr (ClockHasFromSys<T_Clock>) {
// The correct C++20 way to perform the time point conversion.
return T_Clock::from_sys(sys_epoch);
}
else if constexpr (ClockHasFromTime<T_Clock>) {
// Older releases of libcxx did not implement the standard conversion
// function from_sys() for std::chrono::file_clock. Instead the
// non-standard function file_clock::from_time_t() must be used. Since
// libcxx 14.0.0, this has been fixed by:
// - https://reviews.llvm.org/D113027
// - https://reviews.llvm.org/D113430
// TODO(modernize): remove this once we require clang version >= 14.0.0
return T_Clock::from_time_t(
std::chrono::system_clock::to_time_t(sys_epoch));
}
static_assert(std::is_same_v<T_Clock, std::chrono::system_clock> or
ClockHasFromSys<T_Clock> or ClockHasFromTime<T_Clock>,
"Time point conversion function unavailable.");
return {};
}
} // namespace System
#endif // INCLUDED_SRC_BUILDTOOL_SYSTEM_SYSTEM_HPP
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