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sqlpp11/include/sqlpp11/dynamic_select_column_list.h

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/*
* Copyright (c) 2013-2016, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SQLPP_SELECT_COLUMN_LIST_FWD_H
#define SQLPP_SELECT_COLUMN_LIST_FWD_H
#include <vector>
#include <string>
#include <sqlpp11/no_name.h>
#include <sqlpp11/named_interpretable.h>
namespace sqlpp
{
template <typename Db>
struct dynamic_select_column_list
{
using _names_t = std::vector<std::string>;
std::vector<named_interpretable_t<Db>> _dynamic_columns;
_names_t _dynamic_expression_names;
template <typename Expr>
void emplace_back(Expr expr)
{
_dynamic_expression_names.push_back(name_of<Expr>::char_ptr());
_dynamic_columns.emplace_back(expr);
}
bool empty() const
{
return _dynamic_columns.empty();
}
auto size() -> size_t
{
return _dynamic_columns.size();
}
};
template <>
struct dynamic_select_column_list<void>
{
using _names_t = no_name_t;
_names_t _dynamic_expression_names;
static constexpr bool empty()
{
return true;
}
static constexpr auto size() -> size_t
{
return {};
}
};
template <typename Context, typename Db>
struct serializer_t<Context, dynamic_select_column_list<Db>>
{
using T = dynamic_select_column_list<Db>;
static Context& _(const T& t, Context& context)
{
bool first = true;
for (const auto column : t._dynamic_columns)
{
if (first)
first = false;
else
context << ',';
serialize(column, context);
}
return context;
}
};
template <typename Context>
struct serializer_t<Context, dynamic_select_column_list<void>>
{
using T = dynamic_select_column_list<void>;
static Context& _(const T&, Context& context)
{
return context;
}
};
}
#endif