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one/include/ReplicaRequest.h
2018-01-02 18:27:37 +01:00

107 lines
3.1 KiB
C++

/* -------------------------------------------------------------------------- */
/* Copyright 2002-2018, OpenNebula Project, OpenNebula Systems */
/* */
/* 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. */
/* -------------------------------------------------------------------------- */
#ifndef REPLICA_REQUEST_H_
#define REPLICA_REQUEST_H_
#include "SyncRequest.h"
/**
* This class represents a log entry replication request. The replication request
* is synchronous: once it has been replicated in a majority of followers the
* client is notified (SqlDB::exec_wr() call) and DB updated.
*/
class ReplicaRequest : public SyncRequest
{
public:
ReplicaRequest(unsigned int i):_index(i), _to_commit(-1), _replicas(1){};
~ReplicaRequest(){};
/**
* This function updates the number of replicas of the record and decrement
* the number of servers left to reach majority consensus. If it reaches 0,
* the client is notified
* @return number of replicas for this log
*/
int inc_replicas()
{
int __replicas;
_replicas++;
if ( _to_commit > 0 )
{
_to_commit--;
}
__replicas = _replicas;
if ( _to_commit == 0 )
{
result = true;
timeout = false;
notify();
}
return __replicas;
}
/* ---------------------------------------------------------------------- */
/* Class access methods */
/* ---------------------------------------------------------------------- */
int index()
{
return _index;
}
int replicas()
{
return _replicas;
}
int to_commit()
{
return _to_commit;
}
void to_commit(int c)
{
_to_commit = c;
}
private:
/**
* Index for this log entry
*/
unsigned int _index;
/**
* Remaining number of servers that need to replicate this record to commit
* it. Initialized to ( Number_Servers - 1 ) / 2
*/
int _to_commit;
/**
* Total number of replicas for this entry
*/
int _replicas;
};
#endif /*REPLICA_REQUEST_H_*/