sqlpp11/include/sqlpp11/update_list.h

/*
 * Copyright (c) 2013-2015, 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_UPDATE_LIST_H
#define SQLPP_UPDATE_LIST_H

#include <sqlpp11/type_traits.h>
#include <sqlpp11/detail/type_set.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/interpretable_list.h>

namespace sqlpp
{
  // UPDATE ASSIGNMENTS DATA
  template <typename Database, typename... Assignments>
  struct update_list_data_t
  {
    update_list_data_t(Assignments... assignments) : _assignments(assignments...)
    {
    }

    update_list_data_t(const update_list_data_t&) = default;
    update_list_data_t(update_list_data_t&&) = default;
    update_list_data_t& operator=(const update_list_data_t&) = default;
    update_list_data_t& operator=(update_list_data_t&&) = default;
    ~update_list_data_t() = default;

    std::tuple<Assignments...> _assignments;
    interpretable_list_t<Database> _dynamic_assignments;
  };

  struct assert_no_unknown_tables_in_update_assignments_t
  {
    using type = std::false_type;

    template <typename T = void>
    static void _()
    {
      static_assert(wrong_t<T>::value,
                    "at least one update assignment requires a table which is otherwise not known in the statement");
    }
  };

  // UPDATE ASSIGNMENTS
  template <typename Database, typename... Assignments>
  struct update_list_t
  {
    using _traits = make_traits<no_value_t, tag::is_update_list>;
    using _nodes = detail::type_vector<Assignments...>;
    using _is_dynamic = is_database<Database>;

    // Data
    using _data_t = update_list_data_t<Database, Assignments...>;

    // Member implementation with data and methods
    template <typename Policies>
    struct _impl_t
    {
      template <typename Assignment>
      void add_ntc(Assignment assignment)
      {
        add<Assignment, std::false_type>(assignment);
      }

      template <typename Assignment, typename TableCheckRequired = std::true_type>
      void add(Assignment assignment)
      {
        static_assert(_is_dynamic::value, "add must not be called for static from()");
        static_assert(is_assignment_t<Assignment>::value, "invalid assignment argument in add()");
        using _assigned_columns = detail::make_type_set_t<lhs_t<Assignments>...>;
        static_assert(not detail::is_element_of<lhs_t<Assignment>, _assigned_columns>::value,
                      "Must not assign value to column twice");
        static_assert(logic::not_t<must_not_update_t, lhs_t<Assignment>>::value, "add() argument must not be updated");
        static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Assignment>::value,
                      "assignment uses tables unknown to this statement in add()");
        using _serialize_check = sqlpp::serialize_check_t<typename Database::_serializer_context_t, Assignment>;
        _serialize_check::_();

        using ok = logic::all_t<_is_dynamic::value, is_assignment_t<Assignment>::value, _serialize_check::type::value>;

        _add_impl(assignment, ok());  // dispatch to prevent compile messages after the static_assert
      }

    private:
      template <typename Assignment>
      void _add_impl(Assignment assignment, const std::true_type&)
      {
        return _data._dynamic_assignments.emplace_back(assignment);
      }

      template <typename Assignment>
      void _add_impl(Assignment assignment, 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 = update_list_data_t<Database, Assignments...>;

      _impl_t<Policies> assignments;
      _impl_t<Policies>& operator()()
      {
        return assignments;
      }
      const _impl_t<Policies>& operator()() const
      {
        return assignments;
      }

      template <typename T>
      static auto _get_member(T t) -> decltype(t.assignments)
      {
        return t.assignments;
      }

      using _consistency_check = typename std::conditional<Policies::template _no_unknown_tables<update_list_t>::value,
                                                           consistent_t,
                                                           assert_no_unknown_tables_in_update_assignments_t>::type;
    };
  };

  struct assert_update_assignments_t
  {
    using type = std::false_type;

    template <typename T = void>
    static void _()
    {
      static_assert(wrong_t<T>::value, "update assignments required, i.e. set(...)");
    }
  };

  struct no_update_list_t
  {
    using _traits = make_traits<no_value_t, tag::is_where>;
    using _nodes = detail::type_vector<>;

    // 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_assignments;
      _impl_t<Policies>& operator()()
      {
        return no_assignments;
      }
      const _impl_t<Policies>& operator()() const
      {
        return no_assignments;
      }

      template <typename T>
      static auto _get_member(T t) -> decltype(t.no_assignments)
      {
        return t.no_assignments;
      }

      using _database_t = typename Policies::_database_t;

      template <typename... T>
      using _check = logic::all_t<is_assignment_t<T>::value...>;

      template <typename Check, typename T>
      using _new_statement_t = new_statement_t<Check::value, Policies, no_update_list_t, T>;

      using _consistency_check = assert_update_assignments_t;

      template <typename... Assignments>
      auto set(Assignments... assignments) const
          -> _new_statement_t<_check<Assignments...>, update_list_t<void, Assignments...>>
      {
        static_assert(sizeof...(Assignments), "at least one assignment expression required in set()");
        static_assert(_check<Assignments...>::value, "at least one argument is not an assignment in set()");

        return _set_impl<void>(_check<Assignments...>{}, assignments...);
      }

      template <typename... Assignments>
      auto dynamic_set(Assignments... assignments) const
          -> _new_statement_t<_check<Assignments...>, update_list_t<_database_t, Assignments...>>
      {
        static_assert(not std::is_same<_database_t, void>::value,
                      "dynamic_set() must not be called in a static statement");
        static_assert(_check<Assignments...>::value, "at least one argument is not an assignment in set()");

        return _set_impl<_database_t>(_check<Assignments...>{}, assignments...);
      }

    private:
      template <typename Database, typename... Assignments>
      auto _set_impl(const std::false_type&, Assignments... assignments) const -> bad_statement;

      template <typename Database, typename... Assignments>
      auto _set_impl(const std::true_type&, Assignments... assignments) const
          -> _new_statement_t<std::true_type, update_list_t<Database, Assignments...>>
      {
        static_assert(not detail::has_duplicates<lhs_t<Assignments>...>::value,
                      "at least one duplicate column detected in set()");
        static_assert(logic::none_t<must_not_update_t<lhs_t<Assignments>>::value...>::value,
                      "at least one assignment is prohibited by its column definition in set()");

        using _column_required_tables = detail::make_joined_set_t<required_tables_of<lhs_t<Assignments>>...>;
        static_assert(sizeof...(Assignments) ? (_column_required_tables::size::value == 1) : true,
                      "set() contains assignments for columns from more than one table");

        return {static_cast<const derived_statement_t<Policies>&>(*this),
                update_list_data_t<Database, Assignments...>{assignments...}};
      }
    };
  };

  // Interpreters
  template <typename Context, typename Database, typename... Assignments>
  struct serializer_t<Context, update_list_data_t<Database, Assignments...>>
  {
    using _serialize_check = serialize_check_of<Context, Assignments...>;
    using T = update_list_data_t<Database, Assignments...>;

    static Context& _(const T& t, Context& context)
    {
      context << " SET ";
      interpret_tuple(t._assignments, ",", context);
      if (sizeof...(Assignments) and not t._dynamic_assignments.empty())
        context << ',';
      interpret_list(t._dynamic_assignments, ',', context);
      return context;
    }
  };
}

#endif