138 lines
2.6 KiB
C++
138 lines
2.6 KiB
C++
/*
|
|
* Copyright (C) 2021 Emeric Poupon
|
|
*
|
|
* This file is part of LMS.
|
|
*
|
|
* LMS is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* LMS 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 LMS. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "utils/RecursiveSharedMutex.hpp"
|
|
|
|
#include <cassert>
|
|
|
|
void
|
|
RecursiveSharedMutex::lock()
|
|
{
|
|
const auto thisThreadId {std::this_thread::get_id()};
|
|
|
|
if (_uniqueOwner == thisThreadId)
|
|
{
|
|
// already locked
|
|
_uniqueCount++;
|
|
}
|
|
else
|
|
{
|
|
_mutex.lock();
|
|
_uniqueOwner = thisThreadId;
|
|
assert(_uniqueCount == 0);
|
|
_uniqueCount = 1;
|
|
}
|
|
}
|
|
|
|
void
|
|
RecursiveSharedMutex::unlock()
|
|
{
|
|
assert(_uniqueCount > 0);
|
|
|
|
if (--_uniqueCount == 0)
|
|
{
|
|
_uniqueOwner = {};
|
|
_mutex.unlock();
|
|
}
|
|
}
|
|
|
|
void
|
|
RecursiveSharedMutex::lock_shared()
|
|
{
|
|
const auto thisThreadId {std::this_thread::get_id()};
|
|
|
|
if (_uniqueOwner == thisThreadId )
|
|
{
|
|
// alone here, no need to lock
|
|
_sharedCounts[thisThreadId]++;
|
|
|
|
return;
|
|
}
|
|
|
|
bool needLock {};
|
|
|
|
{
|
|
std::scoped_lock lock {_sharedCountMutex};
|
|
|
|
auto& sharedCount {_sharedCounts[thisThreadId]};
|
|
if (sharedCount == 0)
|
|
needLock = true;
|
|
else
|
|
++sharedCount;
|
|
}
|
|
|
|
if (needLock)
|
|
{
|
|
_mutex.lock_shared();
|
|
|
|
assert(_uniqueOwner == std::thread::id {});
|
|
|
|
std::scoped_lock lock {_sharedCountMutex};
|
|
_sharedCounts[thisThreadId]++;
|
|
}
|
|
}
|
|
|
|
void
|
|
RecursiveSharedMutex::unlock_shared()
|
|
{
|
|
const auto thisThreadId {std::this_thread::get_id()};
|
|
|
|
if (_uniqueOwner == thisThreadId )
|
|
{
|
|
// alone here, no need to lock
|
|
auto& sharedCount {_sharedCounts[thisThreadId ]};
|
|
assert(sharedCount > 0);
|
|
--sharedCount;
|
|
|
|
return;
|
|
}
|
|
|
|
bool needUnlock {};
|
|
|
|
{
|
|
std::scoped_lock lock {_sharedCountMutex};
|
|
|
|
auto& sharedCount {_sharedCounts[thisThreadId]};
|
|
assert(sharedCount > 0);
|
|
needUnlock = (--sharedCount == 0);
|
|
}
|
|
|
|
if (needUnlock)
|
|
_mutex.unlock_shared();
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
bool
|
|
RecursiveSharedMutex::isUniqueLocked()
|
|
{
|
|
return _uniqueOwner == std::this_thread::get_id();
|
|
}
|
|
|
|
bool
|
|
RecursiveSharedMutex::isSharedLocked()
|
|
{
|
|
const auto thisThreadId {std::this_thread::get_id()};
|
|
if (_uniqueOwner == thisThreadId )
|
|
return true;
|
|
|
|
std::scoped_lock lock {_sharedCountMutex};
|
|
return _sharedCounts[thisThreadId] > 0;
|
|
}
|
|
#endif
|