0
0
mirror of https://github.com/rbock/sqlpp11.git synced 2024-11-16 12:51:13 +08:00
sqlpp11/include/sqlpp11/is_equal_to_or_null.h

77 lines
3.1 KiB
C++

#pragma once
/*
* Copyright (c) 2021, 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.
*/
#include <sqlpp11/value_or_null.h>
namespace sqlpp
{
template <typename Expr, typename ValueType>
struct is_equal_to_or_null_t: public expression_operators<is_equal_to_or_null_t<Expr, ValueType>, boolean>,
public alias_operators<is_equal_to_or_null_t<Expr, ValueType>>
{
using _traits = make_traits<boolean, tag::is_expression>;
using _nodes = detail::type_vector<Expr, value_or_null_t<ValueType>>;
is_equal_to_or_null_t(Expr expr, value_or_null_t<ValueType> value) : _expr(expr), _value(value)
{
}
is_equal_to_or_null_t(const is_equal_to_or_null_t&) = default;
is_equal_to_or_null_t(is_equal_to_or_null_t&&) = default;
is_equal_to_or_null_t& operator=(const is_equal_to_or_null_t&) = default;
is_equal_to_or_null_t& operator=(is_equal_to_or_null_t&&) = default;
~is_equal_to_or_null_t() = default;
Expr _expr;
value_or_null_t<ValueType> _value;
};
template <typename Context, typename Expr, typename ValueType>
Context& serialize(const is_equal_to_or_null_t<Expr, ValueType>& t, Context& context)
{
if (t._value._is_null)
serialize(t._expr.is_null(), context);
else
serialize(t._expr == t._value, context);
return context;
}
template <typename Expr, typename ValueType>
auto is_equal_to_or_null(Expr expr, value_or_null_t<ValueType> value) -> is_equal_to_or_null_t<Expr, ValueType>
{
static_assert(is_expression_t<Expr>::value,
"is_equal_to_or_null() is to be called an expression (e.g. a column) and a value_or_null expression");
static_assert(std::is_same<value_type_of<Expr>, ValueType>::value,
"is_equal_to_or_null() arguments need to have the same value type");
return {expr, value};
}
} // namespace sqlpp