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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H 10 #define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H 11 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 18 namespace LIBC_NAMESPACE_DECL { 19 namespace 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 of 22 // whether the time is in realtime or monotonic time. 23 class AbsTimeout { 24 timespec timeout; 25 bool realtime_flag; AbsTimeout(timespec ts,bool realtime)26 LIBC_INLINE constexpr explicit AbsTimeout(timespec ts, bool realtime) 27 : timeout(ts), realtime_flag(realtime) {} 28 29 public: 30 enum class Error { Invalid, BeforeEpoch }; get_timespec()31 LIBC_INLINE const timespec &get_timespec() const { return timeout; } is_realtime()32 LIBC_INLINE bool is_realtime() const { return realtime_flag; } 33 LIBC_INLINE static constexpr cpp::expected<AbsTimeout, Error> from_timespec(timespec ts,bool realtime)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 expired 40 // timeout. 41 if (ts.tv_sec < 0) 42 return cpp::unexpected(Error::BeforeEpoch); 43 44 return AbsTimeout{ts, realtime}; 45 } 46 }; 47 } // namespace internal 48 } // namespace LIBC_NAMESPACE_DECL 49 50 #endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H 51