113 lines
2.2 KiB
C++
113 lines
2.2 KiB
C++
/*
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* Copyright (C) 2021 Emeric Poupon
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*
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* This file is part of LMS.
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*
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* LMS is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* LMS is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with LMS. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "utils/RecursiveSharedMutex.hpp"
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#include <cassert>
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void
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RecursiveSharedMutex::lock()
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{
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if (_uniqueOwner == std::this_thread::get_id())
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{
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// already locked
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_uniqueCount++;
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}
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else
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{
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_mutex.lock();
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_uniqueOwner = std::this_thread::get_id();
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assert(_uniqueCount == 0);
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_uniqueCount = 1;
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}
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}
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void
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RecursiveSharedMutex::unlock()
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{
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assert(_uniqueCount > 0);
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if (--_uniqueCount == 0)
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{
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_uniqueOwner = {};
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_mutex.unlock();
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}
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}
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void
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RecursiveSharedMutex::lock_shared()
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{
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if (_uniqueOwner == std::this_thread::get_id())
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{
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// alone here, no need to lock
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_sharedCounts[std::this_thread::get_id()]++;
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return;
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}
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bool needLock {};
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{
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std::scoped_lock lock {_sharedCountMutex};
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auto& sharedCount {_sharedCounts[std::this_thread::get_id()]};
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if (sharedCount == 0)
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needLock = true;
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else
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++sharedCount;
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}
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if (needLock)
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{
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_mutex.lock_shared();
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assert(_uniqueOwner == std::thread::id {});
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std::scoped_lock lock {_sharedCountMutex};
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_sharedCounts[std::this_thread::get_id()]++;
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}
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}
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void
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RecursiveSharedMutex::unlock_shared()
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{
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if (_uniqueOwner == std::this_thread::get_id())
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{
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// alone here, no need to lock
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auto& sharedCount {_sharedCounts[std::this_thread::get_id()]};
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assert(sharedCount > 0);
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--sharedCount;
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return;
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}
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bool needUnlock {};
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{
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std::scoped_lock lock {_sharedCountMutex};
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auto& sharedCount {_sharedCounts[std::this_thread::get_id()]};
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assert(sharedCount > 0);
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needUnlock = (--sharedCount == 0);
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}
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if (needUnlock)
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_mutex.unlock_shared();
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}
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