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sqlpp11/include/sqlpp11/policy_update.h

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2.9 KiB
C++

/*
* Copyright (c) 2013-2014, 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_POLICY_UPDATE_H
#define SQLPP_POLICY_UPDATE_H
#include <sqlpp11/wrong.h>
#include <sqlpp11/bad_statement.h>
namespace sqlpp
{
template<typename Needle, typename Replacement>
struct policy_update_impl
{
template<typename T>
using _policy_t = typename std::conditional<std::is_same<Needle, T>::value, Replacement, T>::type;
};
template<typename T, typename Needle, typename Replacement>
using policy_update_t = typename policy_update_impl<Needle, Replacement>::template _policy_t<T>;
template<typename Original, typename Needle, typename Replacement>
struct update_policies_impl
{
using type = typename Original::template _policy_update_t<Needle, Replacement>;
};
template<typename Original, typename Needle, typename Replacement>
using update_policies_t = typename update_policies_impl<Original, Needle, Replacement>::type;
template<typename Policies, typename Needle, typename Replacement>
using new_statement = typename Policies::template _new_statement_t<Needle, Replacement>;
template<bool, typename Policies, typename Needle, typename Replacement>
struct new_statement_impl
{
using type = typename Policies::template _new_statement_t<Needle, Replacement>;
};
template<typename Policies, typename Needle, typename Replacement>
struct new_statement_impl<false, Policies, Needle, Replacement>
{
using type = bad_statement;
};
template<bool Check, typename Policies, typename Needle, typename Replacement>
using new_statement_t = typename new_statement_impl<Check, Policies, Needle, Replacement>::type;
}
#endif