mirror of https://gitee.com/bigwinds/arangodb
51 lines
1.7 KiB
C++
51 lines
1.7 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Jan Steemann
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////////////////////////////////////////////////////////////////////////////////
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#include "CountCache.h"
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using namespace arangodb;
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using namespace arangodb::transaction;
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CountCache::CountCache() : count(CountCache::NotPopulated), timestamp(0.0) {}
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int64_t CountCache::get() const {
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return count.load(std::memory_order_relaxed);
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}
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int64_t CountCache::get(double ttl) const {
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// (1) - this acquire-load synchronizes with the release-store (2)
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double ts = timestamp.load(std::memory_order_acquire);
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if (ts + Ttl > TRI_microtime()) {
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// not yet expired
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return get();
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}
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return CountCache::NotPopulated;
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}
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void CountCache::store(int64_t value) {
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TRI_ASSERT(value >= 0);
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count.store(value, std::memory_order_relaxed);
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// (2) - this release-store synchronizes with the acquire-load (1)
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timestamp.store(TRI_microtime(), std::memory_order_release);
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}
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