mirror of https://gitee.com/bigwinds/arangodb
68 lines
2.4 KiB
C++
68 lines
2.4 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 "ticks.h"
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#include "Basics/HybridLogicalClock.h"
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using namespace arangodb;
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using namespace arangodb::basics;
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/// @brief current tick identifier (48 bit)
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static std::atomic<uint64_t> CurrentTick(0);
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/// @brief a hybrid logical clock
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static HybridLogicalClock hybridLogicalClock;
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/// @brief create a new tick, using a hybrid logical clock
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TRI_voc_tick_t TRI_HybridLogicalClock() {
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return hybridLogicalClock.getTimeStamp();
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}
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/// @brief create a new tick, using a hybrid logical clock, this variant
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/// is supposed to be called when a time stamp is received in network
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/// communications.
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TRI_voc_tick_t TRI_HybridLogicalClock(TRI_voc_tick_t received) {
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return hybridLogicalClock.getTimeStamp(received);
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}
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/// @brief create a new tick
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TRI_voc_tick_t TRI_NewTickServer() { return ++CurrentTick; }
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/// @brief updates the tick counter, with lock
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void TRI_UpdateTickServer(TRI_voc_tick_t tick) {
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TRI_voc_tick_t t = tick;
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auto expected = CurrentTick.load(std::memory_order_relaxed);
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// only update global tick if less than the specified value...
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while (expected < t &&
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!CurrentTick.compare_exchange_weak(expected, t,
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std::memory_order_release,
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std::memory_order_relaxed)) {
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expected = CurrentTick.load(std::memory_order_relaxed);
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}
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}
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/// @brief returns the current tick counter
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TRI_voc_tick_t TRI_CurrentTickServer() { return CurrentTick; }
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