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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "gc/shared/stringdedup/stringDedupStorageUse.hpp"
#include "runtime/javaThread.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalCounter.inline.hpp"
#include "utilities/globalDefinitions.hpp"

StringDedup::StorageUse::StorageUse(OopStorage* storage) :
  _storage(storage), _use_count(0)
{}

bool StringDedup::StorageUse::is_used_acquire() const {
  return _use_count.load_acquire() > 0;
}

StringDedup::StorageUse*
StringDedup::StorageUse::obtain(Atomic<StorageUse*>* ptr) {
  GlobalCounter::CriticalSection cs(Thread::current());
  StorageUse* storage = ptr->load_relaxed();
  storage->_use_count.add_then_fetch(1u);
  return storage;
}

void StringDedup::StorageUse::relinquish() {
  size_t result = _use_count.fetch_then_sub(1u);
  assert(result != 0, "use count underflow");
}