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Atmosphere/libraries/libmesosphere/source/kern_k_auto_object.cpp
2021-04-19 18:03:27 -07:00

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C++

/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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/>.
*/
#include <mesosphere.hpp>
namespace ams::kern {
KAutoObject *KAutoObject::Create(KAutoObject *obj) {
obj->m_ref_count = 1;
return obj;
}
NOINLINE bool KAutoObject::Open() {
MESOSPHERE_ASSERT_THIS();
/* Atomically increment the reference count, only if it's positive. */
u32 cur_ref_count = m_ref_count.load(std::memory_order_relaxed);
do {
if (AMS_UNLIKELY(cur_ref_count == 0)) {
MESOSPHERE_AUDIT(cur_ref_count != 0);
return false;
}
MESOSPHERE_ABORT_UNLESS(cur_ref_count < cur_ref_count + 1);
} while (!m_ref_count.compare_exchange_weak(cur_ref_count, cur_ref_count + 1, std::memory_order_relaxed));
return true;
}
NOINLINE void KAutoObject::Close() {
MESOSPHERE_ASSERT_THIS();
/* Atomically decrement the reference count, not allowing it to become negative. */
u32 cur_ref_count = m_ref_count.load(std::memory_order_relaxed);
do {
MESOSPHERE_ABORT_UNLESS(cur_ref_count > 0);
} while (!m_ref_count.compare_exchange_weak(cur_ref_count, cur_ref_count - 1, std::memory_order_relaxed));
/* If ref count hits zero, schedule the object for destruction. */
if (cur_ref_count - 1 == 0) {
this->ScheduleDestruction();
}
}
}