/*
 Copyright (c) 2011, Oracle and/or its affiliates. All rights
 reserved.
 
 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; version 2 of
 the License.
 
 This program 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 for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 02110-1301  USA
 */
#ifndef NDBMEMCACHE_CLUSTERCONNECTIONPOOL_H
#define NDBMEMCACHE_CLUSTERCONNECTIONPOOL_H

#define MAX_CONNECT_POOL 4

#include <memcached/engine.h>

#include <NdbApi.hpp>

#include "NdbInstance.h"

class ClusterConnectionPool;

/*  ClusterConnectionPool.cc keeps a global hash table of
 *  ClusterConnectionPool instances, keyed by connect string 
 */  
ClusterConnectionPool * get_connection_pool_for_cluster(const char * connect_string);


class ClusterConnectionPool {

/* public instance variables */
public:
  const char * const connect_string;   /*< cluster connect string */
  unsigned int usec_rtt;         /*< estimated newtork latency within cluster */

/* private instance variables */
private:
  Ndb_cluster_connection *main_conn;                                      
  unsigned int pool_size;                  
  Ndb_cluster_connection * pool_connections[MAX_CONNECT_POOL];
  void * custom_data_ptr;

/* public class methods */
public:
  static Ndb_cluster_connection * connect(const char *connectstring);

/* public instance methods */
public:
  ClusterConnectionPool(const char *s = 0);
  ~ClusterConnectionPool();  
  void setMainConnection(Ndb_cluster_connection *);                  // inlined
  Ndb_cluster_connection *getMainConnection() const      { return main_conn; };
  unsigned int getPoolSize() const                       { return pool_size; }; 

  /** After startup time, create an additional connection in the pool.
      Returns the new connection
  */
  Ndb_cluster_connection * addPooledConnection();

  /** Get the connection numbered "my_id modulo pool_size" */
  Ndb_cluster_connection *getPooledConnection(int my_id) const;      // inlined
  
  /** Get aggregated NDB API client statistics */
  void add_stats(const char *, ADD_STAT, const void *);

  /** Set/get a user-supplied pointer */
  void setCustomData(void *p);
  void * getCustomData();
};


/* Inline functions */

inline void ClusterConnectionPool::setMainConnection(Ndb_cluster_connection *c) {
  main_conn = c;
  pool_size = 1;
  pool_connections[0] = c;
}

inline Ndb_cluster_connection * ClusterConnectionPool::getPooledConnection(int i) const {
  return pool_connections[i % pool_size];
}

inline void ClusterConnectionPool::setCustomData(void *p) {
  custom_data_ptr = p;
}

inline void * ClusterConnectionPool::getCustomData(void) {
  return custom_data_ptr;
}

#endif