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139 lines
4.2 KiB
139 lines
4.2 KiB
//////////////////////////////////////////////////////////// |
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// |
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// SFML - Simple and Fast Multimedia Library |
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// Copyright (C) 2007-2013 Laurent Gomila (laurent.gom@gmail.com) |
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// |
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// This software is provided 'as-is', without any express or implied warranty. |
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// In no event will the authors be held liable for any damages arising from the use of this software. |
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// |
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// Permission is granted to anyone to use this software for any purpose, |
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// including commercial applications, and to alter it and redistribute it freely, |
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// subject to the following restrictions: |
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// |
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// 1. The origin of this software must not be misrepresented; |
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// you must not claim that you wrote the original software. |
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// If you use this software in a product, an acknowledgment |
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// in the product documentation would be appreciated but is not required. |
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// |
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// 2. Altered source versions must be plainly marked as such, |
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// and must not be misrepresented as being the original software. |
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// |
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// 3. This notice may not be removed or altered from any source distribution. |
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// |
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//////////////////////////////////////////////////////////// |
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#ifndef SFML_LOCK_HPP |
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#define SFML_LOCK_HPP |
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//////////////////////////////////////////////////////////// |
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// Headers |
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//////////////////////////////////////////////////////////// |
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#include <SFML/System/Export.hpp> |
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#include <SFML/System/NonCopyable.hpp> |
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namespace sf |
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{ |
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class Mutex; |
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//////////////////////////////////////////////////////////// |
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/// \brief Automatic wrapper for locking and unlocking mutexes |
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/// |
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//////////////////////////////////////////////////////////// |
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class SFML_SYSTEM_API Lock : NonCopyable |
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{ |
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public : |
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//////////////////////////////////////////////////////////// |
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/// \brief Construct the lock with a target mutex |
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/// |
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/// The mutex passed to sf::Lock is automatically locked. |
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/// |
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/// \param mutex Mutex to lock |
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/// |
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//////////////////////////////////////////////////////////// |
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explicit Lock(Mutex& mutex); |
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//////////////////////////////////////////////////////////// |
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/// \brief Destructor |
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/// |
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/// The destructor of sf::Lock automatically unlocks its mutex. |
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/// |
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//////////////////////////////////////////////////////////// |
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~Lock(); |
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private : |
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//////////////////////////////////////////////////////////// |
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// Member data |
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//////////////////////////////////////////////////////////// |
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Mutex& m_mutex; ///< Mutex to lock / unlock |
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}; |
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} // namespace sf |
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#endif // SFML_LOCK_HPP |
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//////////////////////////////////////////////////////////// |
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/// \class sf::Lock |
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/// \ingroup system |
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/// |
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/// sf::Lock is a RAII wrapper for sf::Mutex. By unlocking |
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/// it in its destructor, it ensures that the mutex will |
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/// always be released when the current scope (most likely |
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/// a function) ends. |
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/// This is even more important when an exception or an early |
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/// return statement can interrupt the execution flow of the |
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/// function. |
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/// |
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/// For maximum robustness, sf::Lock should always be used |
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/// to lock/unlock a mutex. |
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/// |
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/// Usage example: |
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/// \code |
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/// sf::Mutex mutex; |
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/// |
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/// void function() |
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/// { |
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/// sf::Lock lock(mutex); // mutex is now locked |
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/// |
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/// functionThatMayThrowAnException(); // mutex is unlocked if this function throws |
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/// |
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/// if (someCondition) |
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/// return; // mutex is unlocked |
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/// |
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/// } // mutex is unlocked |
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/// \endcode |
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/// |
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/// Because the mutex is not explicitely unlocked in the code, |
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/// it may remain locked longer than needed. If the region |
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/// of the code that needs to be protected by the mutex is |
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/// not the entire function, a good practice is to create a |
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/// smaller, inner scope so that the lock is limited to this |
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/// part of the code. |
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/// |
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/// \code |
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/// sf::Mutex mutex; |
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/// |
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/// void function() |
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/// { |
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/// { |
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/// sf::Lock lock(mutex); |
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/// codeThatRequiresProtection(); |
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/// |
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/// } // mutex is unlocked here |
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/// |
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/// codeThatDoesntCareAboutTheMutex(); |
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/// } |
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/// \endcode |
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/// |
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/// Having a mutex locked longer than required is a bad practice |
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/// which can lead to bad performances. Don't forget that when |
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/// a mutex is locked, other threads may be waiting doing nothing |
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/// until it is released. |
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/// |
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/// \see sf::Mutex |
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/// |
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////////////////////////////////////////////////////////////
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