0
0
mirror of https://github.com/rbock/sqlpp11.git synced 2024-11-16 04:47:18 +08:00
sqlpp11/include/sqlpp11/where.h

314 lines
9.5 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_WHERE_H
#define SQLPP_WHERE_H
#include <sqlpp11/statement_fwd.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/parameter_list.h>
#include <sqlpp11/expression.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/interpretable_list.h>
#include <sqlpp11/detail/logic.h>
namespace sqlpp
{
// WHERE DATA
template<typename Database, typename... Expressions>
struct where_data_t
{
where_data_t(Expressions... expressions):
_expressions(expressions...)
{}
where_data_t(const where_data_t&) = default;
where_data_t(where_data_t&&) = default;
where_data_t& operator=(const where_data_t&) = default;
where_data_t& operator=(where_data_t&&) = default;
~where_data_t() = default;
std::tuple<Expressions...> _expressions;
interpretable_list_t<Database> _dynamic_expressions;
};
struct assert_no_unknown_tables_in_where_t
{
using type = std::false_type;
template<typename T = void>
static void _()
{
static_assert(wrong_t<T>::value, "at least one expression in where() requires a table which is otherwise not known in the statement");
}
};
// WHERE(EXPR)
template<typename Database, typename... Expressions>
struct where_t
{
using _traits = make_traits<no_value_t, tag::is_where>;
using _recursive_traits = make_recursive_traits<Expressions...>;
using _is_dynamic = is_database<Database>;
static_assert(_is_dynamic::value or sizeof...(Expressions), "at least one expression argument required in where()");
static_assert(detail::none_t<is_assignment_t<Expressions>::value...>::value, "at least one argument is an assignment in where()");
static_assert(detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not valid expression in where()");
// Data
using _data_t = where_data_t<Database, Expressions...>;
// Member implementation with data and methods
template <typename Policies>
struct _impl_t
{
template<typename Expression>
void add_ntc(Expression expression)
{
add<Expression, std::false_type>(expression);
}
template<typename Expression, typename TableCheckRequired = std::true_type>
void add(Expression expression)
{
static_assert(_is_dynamic::value, "where::add() can only be called for dynamic_where");
static_assert(is_expression_t<Expression>::value, "invalid expression argument in where::add()");
static_assert(not TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in where::add()");
using ok = detail::all_t<_is_dynamic::value, is_expression_t<Expression>::value>;
_add_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
}
private:
template<typename Expression>
void _add_impl(Expression expression, const std::true_type&)
{
return _data._dynamic_expressions.emplace_back(expression);
}
template<typename Expression>
void _add_impl(Expression expression, const std::false_type&);
public:
_data_t _data;
};
// Member template for adding the named member to a statement
template<typename Policies>
struct _member_t
{
using _data_t = where_data_t<Database, Expressions...>;
_impl_t<Policies> where;
_impl_t<Policies>& operator()() { return where; }
const _impl_t<Policies>& operator()() const { return where; }
template<typename T>
static auto _get_member(T t) -> decltype(t.where)
{
return t.where;
}
};
// Additional methods for the statement
template<typename Policies>
struct _methods_t
{
using _consistency_check = typename std::conditional<Policies::template _no_unknown_tables<where_t>::value,
consistent_t,
assert_no_unknown_tables_in_where_t>::type;
};
};
template<>
struct where_data_t<void, bool>
{
bool _condition;
};
// WHERE(BOOL)
template<>
struct where_t<void, bool>
{
using _traits = make_traits<no_value_t, tag::is_where>;
using _recursive_traits = make_recursive_traits<>;
// Data
using _data_t = where_data_t<void, bool>;
// Member implementation with data and methods
template<typename Policies>
struct _impl_t
{
_data_t _data;
};
// Member template for adding the named member to a statement
template<typename Policies>
struct _member_t
{
using _data_t = where_data_t<void, bool>;
_impl_t<Policies> where;
_impl_t<Policies>& operator()() { return where; }
const _impl_t<Policies>& operator()() const { return where; }
template<typename T>
static auto _get_member(T t) -> decltype(t.where)
{
return t.where;
}
};
// Additional methods for the statement
template<typename Policies>
struct _methods_t
{
using _consistency_check = consistent_t;
};
};
struct assert_where_t
{
using type = std::false_type;
template<typename T = void>
static void _()
{
static_assert(wrong_t<T>::value, "where expression required, e.g. where(true)");
};
};
// NO WHERE YET
template<bool WhereRequired>
struct no_where_t
{
using _traits = make_traits<no_value_t, tag::is_where>;
using _recursive_traits = make_recursive_traits<>;
// Data
using _data_t = no_data_t;
// Member implementation with data and methods
template<typename Policies>
struct _impl_t
{
_data_t _data;
};
// Member template for adding the named member to a statement
template<typename Policies>
struct _member_t
{
using _data_t = no_data_t;
_impl_t<Policies> no_where;
_impl_t<Policies>& operator()() { return no_where; }
const _impl_t<Policies>& operator()() const { return no_where; }
template<typename T>
static auto _get_member(T t) -> decltype(t.no_where)
{
return t.no_where;
}
};
// Additional methods for the statement
template<typename Policies>
struct _methods_t
{
using _database_t = typename Policies::_database_t;
template<typename T>
using _new_statement_t = new_statement<Policies, no_where_t, T>;
using _consistency_check = typename std::conditional<
WhereRequired and (Policies::_all_provided_tables::size::value > 0),
assert_where_t,
consistent_t>::type;
template<typename... Args>
auto where(Args... args) const
-> _new_statement_t<where_t<void, Args...>>
{
return { static_cast<const derived_statement_t<Policies>&>(*this), where_data_t<void, Args...>{args...} };
}
template<typename... Args>
auto dynamic_where(Args... args) const
-> _new_statement_t<where_t<_database_t, Args...>>
{
static_assert(not std::is_same<_database_t, void>::value, "dynamic_where must not be called in a static statement");
return { static_cast<const derived_statement_t<Policies>&>(*this), where_data_t<_database_t, Args...>{args...} };
}
};
};
// Interpreters
template<typename Context, typename Database, typename... Expressions>
struct serializer_t<Context, where_data_t<Database, Expressions...>>
{
using _serialize_check = serialize_check_of<Context, Expressions...>;
using T = where_data_t<Database, Expressions...>;
static Context& _(const T& t, Context& context)
{
if (sizeof...(Expressions) == 0 and t._dynamic_expressions.empty())
return context;
context << " WHERE ";
interpret_tuple(t._expressions, " AND ", context);
if (sizeof...(Expressions) and not t._dynamic_expressions.empty())
context << " AND ";
interpret_list(t._dynamic_expressions, " AND ", context);
return context;
}
};
template<typename Context>
struct serializer_t<Context, where_data_t<void, bool>>
{
using _serialize_check = consistent_t;
using T = where_data_t<void, bool>;
static Context& _(const T& t, Context& context)
{
if (not t._condition)
context << " WHERE NULL";
return context;
}
};
template<typename... T>
auto where(T&&... t) -> decltype(statement_t<void, no_where_t<false>>().where(std::forward<T>(t)...))
{
return statement_t<void, no_where_t<false>>().where(std::forward<T>(t)...);
}
}
#endif