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sqlpp11/include/sqlpp11/some.h
2013-11-08 09:09:52 +01:00

95 lines
2.8 KiB
C++

/*
* Copyright (c) 2013, 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_SOME_H
#define SQLPP_SOME_H
#include <sstream>
#include <sqlpp11/boolean.h>
namespace sqlpp
{
namespace detail
{
template<typename Select>
struct some_t: public boolean::template operators<some_t<Select>>
{
static_assert(is_select_t<Select>::value, "some() requires a single column select expression as argument");
static_assert(is_value_t<Select>::value, "some() requires a single column select expression as argument");
struct _value_type: public Select::_value_type::_base_value_type
{
using _is_multi_expression = std::true_type; // must not be named
};
struct _name_t
{
static constexpr const char* _get_name() { return "SOME"; }
template<typename T>
struct _member_t
{
T some;
};
};
some_t(Select&& select):
_select(std::move(select))
{}
some_t(const Select& select):
_select(select)
{}
some_t(const some_t&) = default;
some_t(some_t&&) = default;
some_t& operator=(const some_t&) = default;
some_t& operator=(some_t&&) = default;
~some_t() = default;
template<typename Db>
void serialize(std::ostream& os, Db& db) const
{
static_assert(Db::_supports_some, "some() not supported by current database");
os << "SOME(";
_select.serialize(os, db);
os << ")";
}
private:
Select _select;
};
}
template<typename T>
auto some(T&& t) -> typename detail::some_t<typename operand_t<T, is_select_t>::type>
{
return { std::forward<T>(t) };
}
}
#endif