postgresql_database.h

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// Author(s): Matei Ciocarlie

#ifndef _POSTGRESQL_DATABASE_H_
#define _POSTGRESQL_DATABASE_H_

#include <vector>
#include <string>
#include <boost/shared_ptr.hpp>

//for ROS error messages
#include <ros/ros.h>
#include <yaml-cpp/yaml.h>

#include "database_interface/db_class.h"
#include "database_interface/db_filters.h"

//A bit of an involved way to forward declare PGconn, which is a typedef
struct pg_conn;
typedef struct pg_conn PGconn;

namespace database_interface {

//this is used to pass the information stored in a received notification event
struct Notification {
  std::string channel;
  int sending_pid;
  std::string payload;
};
  
class PostgresqlDatabaseConfig
{
private:
  std::string password_;
  std::string user_;
  std::string host_;
  std::string port_;
  std::string dbname_;

public:
  PostgresqlDatabaseConfig() {  }

  std::string getPassword() const { return password_; }
  std::string getUser() const { return user_; }
  std::string getHost() const { return host_; }
  std::string getPort() const { return port_; }
  std::string getDBname() const { return dbname_; }

  friend void operator>>(const YAML::Node &node, PostgresqlDatabaseConfig &options);
};

void operator>>(const YAML::Node& node, PostgresqlDatabaseConfig &options);

class PostgresqlDatabase
{
 protected:
  void pgMDBconstruct(std::string host, std::string port, std::string user,
                      std::string password, std::string dbname );

  PGconn* connection_;

  class PGresultAutoPtr;

  // beginTransaction sets this flag. endTransaction clears it.
  bool in_transaction_;

  bool getVariable(std::string name, std::string &value) const;
  
  bool rollback();

  bool begin();

  bool commit();

  template <class T>
    bool getList(std::vector< boost::shared_ptr<T> > &vec, const T& example, std::string where_clause) const;

  bool getListRawResult(const DBClass *example, std::vector<const DBFieldBase*> &fields, 
                        std::vector<int> &column_ids, std::string where_clause,
                        boost::shared_ptr<PGresultAutoPtr> &result, int &num_tuples) const;

  bool populateListEntry(DBClass *entry, boost::shared_ptr<PGresultAutoPtr> result, int row_num,
                         const std::vector<const DBFieldBase*> &fields,
                         const std::vector<int> &column_ids) const;

  bool getSequence(std::string name, std::string &value);

  bool insertIntoTable(std::string table_name, const std::vector<const DBFieldBase*> &fields);

  bool deleteFromTable(std::string table_name, const DBFieldBase *key_field);

 public:
  PostgresqlDatabase(std::string host, std::string port, std::string user,
                     std::string password, std::string dbname);

  PostgresqlDatabase(const PostgresqlDatabaseConfig &config);


  ~PostgresqlDatabase();

  bool isConnected() const;

  //------- general queries that should work regardless of the datatypes actually being used ------

  //------- retrieval without examples ------- 
  template <class T>
  bool getList(std::vector< boost::shared_ptr<T> > &vec) const
  {
    T example;
    return getList<T>(vec, example, "");
  }
  template <class T>
  bool getList(std::vector< boost::shared_ptr<T> > &vec, const FilterClause clause) const
  {
    T example;
    return getList<T>(vec, example, clause.clause_);
  }
  template <class T>
  bool getList(std::vector< boost::shared_ptr<T> > &vec, std::string where_clause) const
  {
    T example;
    return getList<T>(vec, example, where_clause);
  }

  //------- retrieval with examples ------- 
  template <class T>
  bool getList(std::vector< boost::shared_ptr<T> > &vec, const T &example) const
  {
    return getList<T>(vec, example, "");
  }
  template <class T>
  bool getList(std::vector< boost::shared_ptr<T> > &vec, const T &example, const FilterClause clause) const
  {
    return getList<T>(vec, example, clause.clause_);
  }

  bool countList(const DBClass *example, int &count, std::string where_clause) const;

  template <typename T>
  bool countList(int &count, const FilterClause clause=FilterClause()) const
  {
    T example;
    return countList(&example, count, clause.clause_);
  }

  bool saveToDatabase(const DBFieldBase* field);

  bool loadFromDatabase(DBFieldBase* field) const;

  bool insertIntoDatabase(DBClass* instance);

  bool deleteFromDatabase(DBClass* instance);
  
  bool listenToChannel(std::string channel);

  bool unlistenToChannel(std::string channel);

  bool checkNotify(Notification &no);

  bool waitForNotify(Notification &no);

};

template <class T>
bool PostgresqlDatabase::getList(std::vector< boost::shared_ptr<T> > &vec, 
                                 const T &example, std::string where_clause) const
{
  //we will store here the fields to be retrieved retrieve from the database
  std::vector<const DBFieldBase*> fields;
  //we will store here their index in the result returned from the database
  std::vector<int> column_ids;
  boost::shared_ptr<PGresultAutoPtr> result;

  int num_tuples;
  //do all the heavy lifting of querying the database and getting the raw result
  if (!getListRawResult(&example, fields, column_ids, where_clause, result, num_tuples))
  {
    return false;
  }

  vec.clear();
  if (!num_tuples)
  {
    return true;
  }

  //parse the raw result and populate the list 
  for (int i=0; i<num_tuples; i++)
  {
    boost::shared_ptr<T> entry(new T);
    if (populateListEntry(entry.get(), result, i, fields, column_ids))
    {
      vec.push_back(entry);
    }
  }
  return true;
}


}//namespace

#endif