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/*
* Copyright © 2013 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Thomas Voss <thomas.voss@canonical.com>
*/
#ifndef CORE_TESTING_CROSS_PROCESS_SYNC_H_
#define CORE_TESTING_CROSS_PROCESS_SYNC_H_
#include <core/posix/visibility.h>
#include <cstdint>
#include <chrono>
#include <stdexcept>
namespace core
{
namespace testing
{
/**
* @brief A cross-process synchronization primitive that supports simple wait-condition-like scenarios.
*/
class CORE_POSIX_DLL_PUBLIC CrossProcessSync
{
public:
struct Error
{
Error() = delete;
~Error() = delete;
/**
* @brief Thrown if any of the *_for functions times out.
*/
struct Timeout : public std::runtime_error
{
Timeout() : std::runtime_error("Timeout while waiting for event to happen.")
{
}
};
};
/**
* @brief Constructs a new sync element.
*/
CrossProcessSync();
/**
* @brief Copy c'tor, duping the underlying fds.
* @param rhs The instance to copy.
*/
CrossProcessSync(const CrossProcessSync& rhs);
/**
* @brief Closes the underlying fds.
*/
~CrossProcessSync() noexcept;
/**
* @brief operator =, dup's the underlying fds.
* @param rhs The instance to assign from.
* @return A mutable reference to this instance.
*/
CrossProcessSync& operator=(const CrossProcessSync& rhs);
/**
* @brief Try to signal the other side that we are ready for at most duration milliseconds.
* @throw Error::Timeout in case of a timeout.
* @throw std::system_error for problems with the underlying pipe.
*/
void try_signal_ready_for(const std::chrono::milliseconds& duration);
/**
* @brief Wait for the other sides to signal readiness for at most duration milliseconds.
* @return The number of ready signals that have been collected since creation.
* @throw Error::Timeout in case of a timeout.
* @throw std::system_error for problems with the underlying pipe.
*/
std::uint32_t wait_for_signal_ready_for(const std::chrono::milliseconds& duration);
private:
int fds[2]; ///< The cross-process pipe.
std::uint32_t counter; ///< Counts the number of times the sync has been signalled.
};
}
}
#endif // CORE_TESTING_CROSS_PROCESS_SYNC_H_
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