libc/src/pthread/pthread_rwlock_clockwrlock.cpp

   1 //===-- Implementation of the Rwlock's clockwrlock function----------------===//
   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 #include "src/pthread/pthread_rwlock_clockwrlock.h"
  10
  11 #include "hdr/errno_macros.h"
  12 #include "src/__support/common.h"
  13 #include "src/__support/macros/config.h"
  14 #include "src/__support/threads/linux/rwlock.h"
  15 #include "src/__support/time/linux/abs_timeout.h"
  16
  17 #include <pthread.h>
  18
  19 namespace LIBC_NAMESPACE_DECL {
  20
  21 static_assert(
  22     sizeof(RwLock) == sizeof(pthread_rwlock_t) &&
  23         alignof(RwLock) == alignof(pthread_rwlock_t),
  24     "The public pthread_rwlock_t type must be of the same size and alignment "
  25     "as the internal rwlock type.");
  26
  27 LLVM_LIBC_FUNCTION(int, pthread_rwlock_clockwrlock,
  28                    (pthread_rwlock_t * rwlock, clockid_t clockid,
  29                     const timespec *abstime)) {
  30   if (!rwlock)
  31     return EINVAL;
  32   if (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME)
  33     return EINVAL;
  34   bool is_realtime = (clockid == CLOCK_REALTIME);
  35   RwLock *rw = reinterpret_cast<RwLock *>(rwlock);
  36   LIBC_ASSERT(abstime && "clockwrlock called with a null timeout");
  37   auto timeout = internal::AbsTimeout::from_timespec(
  38       *abstime, /*is_realtime=*/is_realtime);
  39   if (LIBC_LIKELY(timeout.has_value()))
  40     return static_cast<int>(rw->write_lock(timeout.value()));
  41
  42   switch (timeout.error()) {
  43   case internal::AbsTimeout::Error::Invalid:
  44     return EINVAL;
  45   case internal::AbsTimeout::Error::BeforeEpoch:
  46     return ETIMEDOUT;
  47   }
  48   __builtin_unreachable();
  49 }
  50
  51 } // namespace LIBC_NAMESPACE_DECL