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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/synchronization/cancelable_event.h"
#include <windows.h>
#include <synchapi.h>
#include <tuple>
#include "base/synchronization/lock.h"
#include "base/win/winbase_shim.h"
namespace base {
CancelableEvent::CancelableEvent() {
native_handle_ = ::CreateSemaphoreA(nullptr, 0, 1, nullptr);
PCHECK(!!native_handle_);
}
CancelableEvent::~CancelableEvent() {
const bool result = ::CloseHandle(native_handle_);
PCHECK(result);
}
void CancelableEvent::SignalImpl() {
LONG prev_count;
const bool result = ::ReleaseSemaphore(native_handle_, 1, &prev_count);
PCHECK(result);
CHECK_EQ(prev_count, 0);
}
bool CancelableEvent::CancelImpl() {
const DWORD result = ::WaitForSingleObject(native_handle_, 0);
return result == WAIT_OBJECT_0;
}
bool CancelableEvent::TimedWaitImpl(TimeDelta timeout) {
const DWORD wait_ms = saturated_cast<DWORD>(timeout.InMilliseconds());
const TimeTicks start = TimeTicks::Now();
DWORD result;
// WaitForSingleObject has been shown to experience spurious wakeups (on the
// order of 10ms before when it was supposed to wake up), so retry until at
// least `timeout` has passed.
do {
result = ::WaitForSingleObject(native_handle_, wait_ms);
if (result == WAIT_OBJECT_0) {
return true;
}
} while (TimeTicks::Now() <= start + timeout);
CHECK_EQ(result, static_cast<DWORD>(WAIT_TIMEOUT));
return false;
}
} // namespace base
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