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// Copyright (c) 2022 Klemens D. Morgenstern
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_SQLITE_RESULTSET_HPP
#define BOOST_SQLITE_RESULTSET_HPP
#include <memory>
#include <boost/sqlite/row.hpp>
#include <boost/describe/members.hpp>
#include <boost/system/result.hpp>
BOOST_SQLITE_BEGIN_NAMESPACE
struct connection ;
/**
@brief Representation of a result from a database.
@ingroup reference
If is a forward-range with output iterators.
@par Example
@code{.cpp}
extern sqlite::connection conn;
sqlite::resultset rs = conn.query("select * from users;");
do
{
handle_row(r.current());
}
while (rs.read_next()) // read it line by line
@endcode
*/
struct resultset
{
/// Returns the current row.
row current() const &
{
row r;
r.stm_ = impl_.get();
return r;
}
/// Checks if the last row has been reached.
bool done() const {return done_;}
///@{
/// Read the next row. Returns false if there's nothing more to read.
BOOST_SQLITE_DECL bool read_next(system::error_code & ec, error_info & ei);
BOOST_SQLITE_DECL bool read_next();
///@}
///
std::size_t column_count() const
{
return sqlite3_column_count(impl_.get());
}
/// Returns the name of the column idx.
cstring_ref column_name(std::size_t idx) const
{
return sqlite3_column_name(impl_.get(), static_cast<int>(idx));
}
/// Returns the name of the source table for column idx.
cstring_ref table_name(std::size_t idx) const
{
return sqlite3_column_table_name(impl_.get(), static_cast<int>(idx));
}
/// Returns the origin name of the column for column idx.
cstring_ref column_origin_name(std::size_t idx) const
{
return sqlite3_column_origin_name(impl_.get(), static_cast<int>(idx));
}
/// The input iterator can be used to read every row in a for-loop
struct iterator
{
using value_type = value;
using difference_type = int;
using reference = value&;
using iterator_category = std::forward_iterator_tag;
iterator() {}
explicit iterator(sqlite3_stmt * stmt, bool sentinel) : sentinel_(sentinel )
{
row_.stm_ = stmt;
}
bool operator!=(iterator rhs) const
{
return sentinel_ != rhs.sentinel_;
}
row &operator*() { return row_; }
row *operator->() { return &row_; }
BOOST_SQLITE_DECL
iterator operator++();
iterator operator++(int)
{
auto l = *this;
++(*this);
return l;
}
private:
row row_;
bool sentinel_ = true;
};
/// Return an input iterator to the currently unread row
iterator begin() { return iterator(impl_.get(), done_);}
/// Sentinel iterator.
iterator end() { return iterator(impl_.get(), true); }
private:
friend struct connection;
friend struct statement;
struct deleter_
{
constexpr deleter_() noexcept {}
bool delete_ = true;
void operator()(sqlite3_stmt * sm)
{
if (sqlite3_data_count(sm) > 0)
while ( sqlite3_step(sm) == SQLITE_ROW);
if (delete_)
sqlite3_finalize(sm);
else
{
sqlite3_clear_bindings(sm);
sqlite3_reset(sm);
}
}
};
std::unique_ptr<sqlite3_stmt, deleter_> impl_;
bool done_ = false;
};
BOOST_SQLITE_END_NAMESPACE
#endif //BOOST_SQLITE_RESULTSET_HPP
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