DBInterface.h

#ifndef DBInterface_H_
#define DBInterface_H_
// --------------------------------------------------------------------------
#include <string>
#include <deque>
#include <vector>
#include <unordered_map>
#include "UniSetTypes.h"
// --------------------------------------------------------------------------
namespace uniset
{
    class DBResult;

    class DBInterface
    {
        public:
 
            DBInterface() {}
            virtual ~DBInterface() {}
 
            // Функция подключения к БД, параметры подключения зависят от типа БД
            virtual bool connect( const std::string& param ) = 0;
            virtual bool close() = 0;
            virtual bool isConnection() const = 0;
            virtual bool ping() const = 0; // проверка доступности БД
 
            virtual DBResult query( const std::string& q ) = 0;
            virtual void cancel_query() {}; // попытка отменить текущий запрос
            virtual const std::string lastQuery() = 0;
            virtual bool insert( const std::string& q ) = 0;
            virtual double insert_id() = 0;
            virtual const std::string error() = 0;
    };
    // ----------------------------------------------------------------------------------
    class DBNetInterface : public DBInterface
    {
        public:
 
            DBNetInterface() {}
            virtual ~DBNetInterface() {}
 
            // Для сетевых БД параметры должны быть в формате user@host:pswd:dbname:port
            virtual bool connect( const std::string& param );
            virtual bool nconnect( const std::string& host, const std::string& user, const std::string& pswd,
                                   const std::string& dbname, unsigned int port ) = 0;
    };
    // ----------------------------------------------------------------------------------
    class DBRowIterator;
 
    class DBResult
    {
        public:
 
            DBResult() {}
            virtual ~DBResult() {}
 
            typedef std::vector<std::string> COL;
            typedef std::deque<COL> ROW;
            typedef DBRowIterator iterator;
 
            ROW& row();
            iterator begin();
            iterator end();
            operator bool() const;
            size_t size() const;
            bool empty() const;

            void setColName( int index, const std::string& name );

            int getColIndex( const std::string& name );
 
            // slow function
            std::string getColName( int index );
 
            // ----------------------------------------------------------------------------
            // COL
            static int as_int( const DBResult::COL::iterator& it );
            static double as_double(const  DBResult::COL::iterator& it );
            static std::string as_string( const DBResult::COL::iterator& it );
            static size_t num_cols( const DBResult::iterator& it );
            // ----------------------------------------------------------------------------
 
        protected:
 
            ROW row_;
 
            std::unordered_map<std::string, int> colname;
    };
    // ----------------------------------------------------------------------------------
    class DBRowIterator
    {
 
        public:
            using iterator_category = std::bidirectional_iterator_tag;
            using value_type = DBResult::ROW::value_type;
            using difference_type = DBResult::ROW::difference_type;
            using pointer = DBResult::ROW::pointer;
            using reference = DBResult::ROW::reference;
 
            std::string as_string( const char* name ) const;
            std::string as_string( const std::string& name ) const;
            int as_int( const std::string& name ) const;
            double as_double( const std::string& name ) const;
 
            std::string as_string( int col ) const;
            int as_int( int col ) const;
            double as_double( int col ) const;
 
            size_t num_cols() const;
 
            typename DBRowIterator::pointer operator->();
            typename DBRowIterator::reference operator*() const;
 
            DBRowIterator( const DBRowIterator& it );
 
            bool operator!=(DBRowIterator const& ) const;
            bool operator==(DBRowIterator const& ) const;
            DBRowIterator& operator+(int) noexcept;
            DBRowIterator& operator+=(int) noexcept;
            DBRowIterator& operator++() noexcept;   // ++x
            DBRowIterator operator++(int) noexcept; // x++
            DBRowIterator& operator-(int) noexcept;
            DBRowIterator operator--(int) noexcept; // x--
            DBRowIterator& operator--() noexcept; // --x
            DBRowIterator& operator-=(int) noexcept;
 
        private:
            friend class DBResult;
            DBRowIterator( DBResult& dbres, const DBResult::ROW::iterator& );
 
            DBResult& dbres;
            DBResult::ROW::iterator it;
    };
 
    // ----------------------------------------------------------------------------------
    struct DBInterfaceDeleter
    {
        void operator()(DBInterface* p) const
        {
            try
            {
                delete p;
            }
            catch(...) {}
        }
    };
    // ----------------------------------------------------------------------------------
    // the types of the class factories
    typedef std::shared_ptr<DBInterface> create_dbinterface_t();
    // --------------------------------------------------------------------------
} // end of uniset namespace
// -------------------------------------------------------------------------
#endif // DBInterface_H_
// --------------------------------------------------------------------------