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sqlpp11/include/sqlpp11/from.h

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8.3 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_FROM_H
#define SQLPP_FROM_H
#include <sqlpp11/table_ref.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/no_data.h>
#include <sqlpp11/interpretable_list.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/logic.h>
#include <sqlpp11/detail/sum.h>
#include <sqlpp11/policy_update.h>
namespace sqlpp
{
// FROM DATA
template<typename Database, typename... Tables>
struct from_data_t
{
from_data_t(Tables... tables):
_tables(tables...)
{}
from_data_t(const from_data_t&) = default;
from_data_t(from_data_t&&) = default;
from_data_t& operator=(const from_data_t&) = default;
from_data_t& operator=(from_data_t&&) = default;
~from_data_t() = default;
std::tuple<Tables...> _tables;
interpretable_list_t<Database> _dynamic_tables;
};
// FROM
template<typename Database, typename... Tables>
struct from_t
{
using _traits = make_traits<no_value_t, tag::is_from>;
using _recursive_traits = make_recursive_traits<Tables...>;
using _is_dynamic = is_database<Database>;
// Data
using _data_t = from_data_t<Database, Tables...>;
// Member implementation with data and methods
template<typename Policies>
struct _impl_t
{
template<typename Table>
void add(Table table)
{
static_assert(_is_dynamic::value, "from::add() must not be called for static from()");
static_assert(is_table_t<Table>::value, "invalid table argument in from::add()");
using _known_tables = detail::make_joined_set_t<provided_tables_of<Tables>...>; // Hint: Joins contain more than one table
using _known_table_names = detail::transform_set_t<name_of, _known_tables>;
static_assert(not detail::is_element_of<typename Table::_alias_t, _known_table_names>::value, "Must not use the same table name twice in from()");
using _serialize_check = sqlpp::serialize_check_t<typename Database::_serializer_context_t, Table>;
_serialize_check::_();
using ok = logic::all_t<_is_dynamic::value, is_table_t<Table>::value, _serialize_check::type::value>;
_add_impl(table, ok()); // dispatch to prevent compile messages after the static_assert
}
private:
template<typename Table>
void _add_impl(Table table, const std::true_type&)
{
return _data._dynamic_tables.emplace_back(from_table(table));
}
template<typename Table>
void _add_impl(Table table, const std::false_type&);
public:
_data_t _data;
};
// Base template to be inherited by the statement
template<typename Policies>
struct _base_t
{
using _data_t = from_data_t<Database, Tables...>;
_impl_t<Policies> from;
_impl_t<Policies>& operator()() { return from; }
const _impl_t<Policies>& operator()() const { return from; }
template<typename T>
static auto _get_member(T t) -> decltype(t.from)
{
return t.from;
}
// FIXME: We might want to check if we have too many tables define in the FROM
using _consistency_check = consistent_t;
};
};
struct no_from_t
{
using _traits = make_traits<no_value_t, tag::is_noop>;
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;
};
// Base template to be inherited by the statement
template<typename Policies>
struct _base_t
{
using _data_t = no_data_t;
_impl_t<Policies> no_from;
_impl_t<Policies>& operator()() { return no_from; }
const _impl_t<Policies>& operator()() const { return no_from; }
template<typename T>
static auto _get_member(T t) -> decltype(t.no_from)
{
return t.no_from;
}
using _database_t = typename Policies::_database_t;
template<typename... T>
using _check = logic::all_t<is_table_t<T>::value...>;
template<typename Check, typename T>
using _new_statement_t = new_statement_t<Check::value, Policies, no_from_t, T>;
using _consistency_check = consistent_t;
template<typename... Tables>
auto from(Tables... tables) const
-> _new_statement_t<_check<Tables...>, from_t<void, from_table_t<Tables>...>>
{
static_assert(_check<Tables...>::value, "at least one argument is not a table or join in from()");
static_assert(sizeof...(Tables), "at least one table or join argument required in from()");
return _from_impl<void>(_check<Tables...>{}, tables...);
}
template<typename... Tables>
auto dynamic_from(Tables... tables) const
-> _new_statement_t<_check<Tables...>, from_t<_database_t, from_table_t<Tables>...>>
{
static_assert(not std::is_same<_database_t, void>::value, "dynamic_from must not be called in a static statement");
static_assert(_check<Tables...>::value, "at least one argument is not a table or join in from()");
return _from_impl<_database_t>(_check<Tables...>{}, tables...);
}
private:
template<typename Database, typename... Tables>
auto _from_impl(const std::false_type&, Tables... tables) const
-> bad_statement;
template<typename Database, typename... Tables>
auto _from_impl(const std::true_type&, Tables... tables) const
-> _new_statement_t<std::true_type, from_t<Database, from_table_t<Tables>...>>
{
static_assert(required_tables_of<from_t<Database, Tables...>>::size::value == 0, "at least one table depends on another table in from()");
static constexpr std::size_t _number_of_tables = detail::sum(provided_tables_of<Tables>::size::value...);
using _unique_tables = detail::make_joined_set_t<provided_tables_of<Tables>...>;
using _unique_table_names = detail::transform_set_t<name_of, _unique_tables>;
static_assert(_number_of_tables == _unique_tables::size::value, "at least one duplicate table detected in from()");
static_assert(_number_of_tables == _unique_table_names::size::value, "at least one duplicate table name detected in from()");
return { static_cast<const derived_statement_t<Policies>&>(*this), from_data_t<Database, from_table_t<Tables>...>{from_table(tables)...} };
}
};
};
// Interpreters
template<typename Context, typename Database, typename... Tables>
struct serializer_t<Context, from_data_t<Database, Tables...>>
{
using _serialize_check = serialize_check_of<Context, Tables...>;
using T = from_data_t<Database, Tables...>;
static Context& _(const T& t, Context& context)
{
if (sizeof...(Tables) == 0 and t._dynamic_tables.empty())
return context;
context << " FROM ";
interpret_tuple(t._tables, ',', context);
if (sizeof...(Tables) and not t._dynamic_tables.empty())
context << ',';
interpret_list(t._dynamic_tables, ',', context);
return context;
}
};
template<typename... T>
auto from(T&&... t) -> decltype(statement_t<void, no_from_t>().from(std::forward<T>(t)...))
{
return statement_t<void, no_from_t>().from(std::forward<T>(t)...);
}
}
#endif