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// Copyright 2020 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#pragma once
#include "pw_chrono/system_clock.h"
#include "pw_sync/binary_semaphore.h"
namespace pw::sync {
inline BinarySemaphore::BinarySemaphore()
: native_type_{.mutex = {}, .condition = {}, .count = 0} {}
inline BinarySemaphore::~BinarySemaphore() {}
inline bool BinarySemaphore::try_acquire_for(
chrono::SystemClock::duration timeout) {
// Due to spurious condition variable wakeups we prefer not to use wait_for()
// as we may grossly extend the effective deadline after a spruious wakeup.
// Ergo we instead use the derived deadline which can be re-used many times
// without shifting the effective deadline. For more details on spurious
// wakeups and CVs on Windows and POSIX see:
// https://en.wikipedia.org/wiki/Spurious_wakeup
return try_acquire_until(chrono::SystemClock::TimePointAfterAtLeast(timeout));
}
inline BinarySemaphore::native_handle_type BinarySemaphore::native_handle() {
return native_type_;
}
} // namespace pw::sync