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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/Assertions.h"
#include <float.h>
#include <intrin.h>
#include <stdlib.h>
#include <windows.h>
#include "mozilla/PlatformConditionVariable.h"
#include "mozilla/PlatformMutex.h"
#include "MutexPlatformData_windows.h"
// Some versions of the Windows SDK have a bug where some interlocked functions
// are not redefined as compiler intrinsics. Fix that for the interlocked
// functions that are used in this file.
#if defined(_MSC_VER) && !defined(InterlockedExchangeAdd)
# define InterlockedExchangeAdd(addend, value) \
_InterlockedExchangeAdd((volatile long*)(addend), (long)(value))
#endif
#if defined(_MSC_VER) && !defined(InterlockedIncrement)
# define InterlockedIncrement(addend) \
_InterlockedIncrement((volatile long*)(addend))
#endif
// Wrapper for native condition variable APIs.
struct mozilla::detail::ConditionVariableImpl::PlatformData {
CONDITION_VARIABLE cv_;
};
mozilla::detail::ConditionVariableImpl::ConditionVariableImpl() {
InitializeConditionVariable(&platformData()->cv_);
}
void mozilla::detail::ConditionVariableImpl::notify_one() {
WakeConditionVariable(&platformData()->cv_);
}
void mozilla::detail::ConditionVariableImpl::notify_all() {
WakeAllConditionVariable(&platformData()->cv_);
}
void mozilla::detail::ConditionVariableImpl::wait(MutexImpl& lock) {
SRWLOCK* srwlock = &lock.platformData()->lock;
bool r =
SleepConditionVariableSRW(&platformData()->cv_, srwlock, INFINITE, 0);
MOZ_RELEASE_ASSERT(r);
}
mozilla::CVStatus mozilla::detail::ConditionVariableImpl::wait_for(
MutexImpl& lock, const mozilla::TimeDuration& rel_time) {
if (rel_time == mozilla::TimeDuration::Forever()) {
wait(lock);
return CVStatus::NoTimeout;
}
SRWLOCK* srwlock = &lock.platformData()->lock;
// Note that DWORD is unsigned, so we have to be careful to clamp at 0. If
// rel_time is Forever, then ToMilliseconds is +inf, which evaluates as
// greater than UINT32_MAX, resulting in the correct INFINITE wait. We also
// don't want to round sub-millisecond waits to 0, as that wastes energy (see
// bug 1437167 comment 6), so we instead round submillisecond waits to 1ms.
double msecd = rel_time.ToMilliseconds();
DWORD msec;
if (msecd < 0.0) {
msec = 0;
} else if (msecd > UINT32_MAX) {
msec = INFINITE;
} else {
msec = static_cast<DWORD>(msecd);
// Round submillisecond waits to 1ms.
if (msec == 0 && !rel_time.IsZero()) {
msec = 1;
}
}
BOOL r = SleepConditionVariableSRW(&platformData()->cv_, srwlock, msec, 0);
if (r) return CVStatus::NoTimeout;
MOZ_RELEASE_ASSERT(GetLastError() == ERROR_TIMEOUT);
return CVStatus::Timeout;
}
mozilla::detail::ConditionVariableImpl::~ConditionVariableImpl() {
// Native condition variables don't require cleanup.
}
inline mozilla::detail::ConditionVariableImpl::PlatformData*
mozilla::detail::ConditionVariableImpl::platformData() {
static_assert(sizeof platformData_ >= sizeof(PlatformData),
"platformData_ is too small");
return reinterpret_cast<PlatformData*>(platformData_);
}