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1//===--- Linux absolute timeout ---------------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H10#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H11 12#include "hdr/time_macros.h"13#include "hdr/types/struct_timespec.h"14#include "src/__support/CPP/expected.h"15#include "src/__support/macros/config.h"16#include "src/__support/time/units.h"17 18namespace LIBC_NAMESPACE_DECL {19namespace internal {20// We use AbsTimeout to remind ourselves that the timeout is an absolute time.21// This is a simple wrapper around the timespec struct that also keeps track of22// whether the time is in realtime or monotonic time.23class AbsTimeout {24 timespec timeout;25 bool realtime_flag;26 LIBC_INLINE constexpr explicit AbsTimeout(timespec ts, bool realtime)27 : timeout(ts), realtime_flag(realtime) {}28 29public:30 enum class Error { Invalid, BeforeEpoch };31 LIBC_INLINE const timespec &get_timespec() const { return timeout; }32 LIBC_INLINE bool is_realtime() const { return realtime_flag; }33 LIBC_INLINE static constexpr cpp::expected<AbsTimeout, Error>34 from_timespec(timespec ts, bool realtime) {35 using namespace time_units;36 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1_s_ns)37 return cpp::unexpected(Error::Invalid);38 39 // POSIX allows tv_sec to be negative. We interpret this as an expired40 // timeout.41 if (ts.tv_sec < 0)42 return cpp::unexpected(Error::BeforeEpoch);43 44 return AbsTimeout{ts, realtime};45 }46};47} // namespace internal48} // namespace LIBC_NAMESPACE_DECL49 50#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H51