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arangodb/arangod/Agency/Log.h

130 lines
3.1 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Kaveh Vahedipour
////////////////////////////////////////////////////////////////////////////////
#ifndef __ARANGODB_CONSENSUS_LOG__
#define __ARANGODB_CONSENSUS_LOG__
#include "AgencyCommon.h"
#include "State.h"
#include <Basics/Thread.h>
#include <Cluster/ClusterComm.h>
#include <velocypack/vpack.h>
#include <cstdint>
#include <functional>
//using namespace arangodb::velocypack;
class Slice {};
namespace arangodb {
namespace consensus {
class Agent;
/**
* @brief Log replica
*/
class Log : public arangodb::Thread, public arangodb::ClusterCommCallback,
std::enable_shared_from_this<Log> {
public:
typedef uint64_t index_t;
typedef int32_t ret_t;
/**
* @brief Default constructor
*/
Log ();
/**
* @brief Default Destructor
*/
virtual ~Log();
void configure(Agent* agent);
/**
* @brief Log
*/
template<typename T> ret_t log (T const&);
/**
* @brief Call back for log results from slaves
*/
virtual bool operator()(ClusterCommResult*);
/**
* @brief My daily business
*/
void run();
/**
* @brief
*/
void respHandler (index_t);
private:
/**
* @brief Write transaction
* @param state State demanded
* @param expiry Time of expiration
* @param update Update state
*/
template<typename T> std::shared_ptr<T> readTransaction (
T const& state, T const& update);
/**
* @brief Write transaction
* @param state State demanded
* @param expiry Time of expiration
* @param update Update state
*/
template<typename T> std::shared_ptr<T> writeTransaction (
T const& state, duration_t expiry, T const& update);
/**
* @brief Check transaction condition
* @param state State demanded
* @param pre Prerequisite
*/
template<typename T> bool checkTransactionPrecondition (
T const& state, T const& pre);
index_t _commit_id; /**< @brief index of highest log entry known
to be committed (initialized to 0, increases monotonically) */
index_t _last_applied; /**< @brief index of highest log entry applied to state machine */
State _state; /**< @brief State machine */
Agent* _agent; /**< @brief My boss */
};
}}
#endif