insertpolicy.h

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#if !defined(MYSQLPP_INSERTPOLICY_H)
#define MYSQLPP_INSERTPOLICY_H
 
// Only allow these templates to be defined if they're being bodily
// included into class Query's definition.  They're in this separate
// file only for claity, so they don't get lost among the other
// definitions in class Query.  Without this, Doxygen will pick them
// up and treat them as a) outside namespace mysqlpp; and b) not member
// templates of class Query.  We also don't want end-users of the
// library to #include this file in their own code; these templates
// should only be used as mysqlpp::Query::*.
#if defined(MYSQLPP_DEFINE_INSERT_POLICY_TEMPLATES)
 
 
template <class AccessController = Transaction>
class MYSQLPP_EXPORT RowCountInsertPolicy
{
public:
        RowCountInsertPolicy(unsigned int rows) :
        cur_rows_(0),
        max_rows_(rows)
        {
        }
 
        ~RowCountInsertPolicy() { }
 
        template <class RowT>
        bool can_add(int, const RowT&)
        {
                if (++cur_rows_ > max_rows_) {
                        cur_rows_ = 0;
                        return false;
                }
                else {
                        return true;
                }
        }
 
        typedef AccessController access_controller;
 
private:
        unsigned int cur_rows_;
        unsigned const int max_rows_;
};
 
 
template <class AccessController = Transaction>
class MYSQLPP_EXPORT SizeThresholdInsertPolicy
{
public:
        SizeThresholdInsertPolicy(int size) :
        size_(size)
        {
        }
 
        ~SizeThresholdInsertPolicy() { }
 
        template <class RowT>
        bool can_add(int size, const RowT& object) const
        {
                (void)object;           // we don't use this, but other policies do
                return (size < size_);
        }
 
        typedef AccessController access_controller;
 
private:
        int size_;
};
 
 
template <class AccessController = Transaction>
class MYSQLPP_EXPORT MaxPacketInsertPolicy
{
public:
        MaxPacketInsertPolicy(Connection* con, int size) :
        conn_(con), size_(size)
        {
        }
 
        MaxPacketInsertPolicy(int size) :
        conn_(0), size_(size)
        {
        }
 
        ~MaxPacketInsertPolicy() { }
 
        template <class RowT>
        bool can_add(int size, const RowT& object) const
        {
                if (size < size_) {
                        // Haven't hit size threshold yet, so see if this next
                        // item pushes it over the line.
                        SQLStream s(conn_);
                        s << ",(" << object.value_list() << ")";
                        return (size_ - size) >= static_cast<int>(s.str().size());
                }
                else {
                        // Already too much in query buffer!
                        return false;
                }
        }
 
        typedef AccessController access_controller;
 
private:
        Connection* conn_;
        int size_;
};
 
#endif // defined(MYSQLPP_DEFINE_INSERT_POLICY_TEMPLATES)
 
#endif // !defined(MYSQLPP_INSERTPOLICY_H)