Mark Mentovai 10c264cd57 Add Semaphore::TimedWait().
This also splits the per-OS Semaphore methods into their own files.

TEST=util_test Semaphore.*
R=rsesek@chromium.org, scottmg@chromium.org

Review URL: https://codereview.chromium.org/909263002
2015-02-10 17:01:58 -05:00

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// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// 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
//
// http://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.
#ifndef CRASHPAD_UTIL_SYNCHRONIZATION_SEMAPHORE_H_
#define CRASHPAD_UTIL_SYNCHRONIZATION_SEMAPHORE_H_
#include "build/build_config.h"
#if defined(OS_MACOSX)
#include <dispatch/dispatch.h>
#elif defined(OS_WIN)
#include <windows.h>
#else
#include <semaphore.h>
#endif
namespace crashpad {
//! \brief An anonymous in-process counting sempahore.
class Semaphore {
public:
//! \brief Initializes the semaphore.
//!
//! \param[in] value The initial value of the semaphore.
//!
//! If the semaphore cannot be created, execution is terminated.
explicit Semaphore(int value);
~Semaphore();
//! \brief Performs the wait (or “procure”) operation on the semaphore.
//!
//! Atomically decrements the value of the semaphore by 1. If the new value is
//! negative, this function blocks and will not return until the semaphores
//! value is incremented to 0 by Signal().
//!
//! \sa TimedWait()
void Wait();
//! \brief Performs a timed wait (or “procure”) operation on the semaphore.
//!
//! \param[in] seconds The maximum number of seconds to wait for the operation
//! to complete.
//!
//! \return `false` if the wait timed out, `true` otherwise.
//!
//! This method is simlar to Wait(), except that the amount of time that it
//! blocks is limited.
bool TimedWait(double seconds);
//! \brief Performs the signal (or “post”) operation on the semaphore.
//!
//! Atomically increments the value of the semaphore by 1. If the new value is
//! 0, a caller blocked in Wait() will be awakened.
void Signal();
private:
#if defined(OS_MACOSX)
dispatch_semaphore_t semaphore_;
#elif defined(OS_WIN)
HANDLE semaphore_;
#else
sem_t semaphore_;
#endif
};
} // namespace crashpad
#endif // CRASHPAD_UTIL_SYNCHRONIZATION_SEMAPHORE_H_