sqlpp11/include/sqlpp11/with.h

/*
 * Copyright (c) 2013-2016, 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_WITH_H
#define SQLPP_WITH_H

#include <sqlpp11/assignment.h>
#include <sqlpp11/column_fwd.h>
#include <sqlpp11/expression.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/interpretable_list.h>
#include <sqlpp11/logic.h>
#include <sqlpp11/no_data.h>
#include <sqlpp11/parameter_list.h>
#include <sqlpp11/policy_update.h>
#include <sqlpp11/statement_fwd.h>
#include <sqlpp11/type_traits.h>

#include <sqlpp11/cte.h>

namespace sqlpp
{
  template <typename Database, typename... Expressions>
  struct with_data_t
  {
    using _is_recursive = logic::any_t<Expressions::_is_recursive...>;

    with_data_t(Expressions... expressions) : _expressions(expressions...)
    {
    }

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

    std::tuple<Expressions...> _expressions;
  };

  template <typename Database, typename... Expressions>
  struct with_t
  {
    using _traits = make_traits<no_value_t, tag::is_with>;
    using _nodes = detail::type_vector<>;
    using _provided_ctes =
        detail::make_joined_set_t<required_ctes_of<Expressions>...>;  // WITH provides common table expressions
    using _parameters = detail::type_vector_cat_t<parameters_of<Expressions>...>;

    using _is_dynamic = is_database<Database>;

    // Data
    using _data_t = with_data_t<Database, Expressions...>;

    // Member implementation with data and methods
    template <typename Policies>
    struct _impl_t
    {
      // workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
      _impl_t() = default;
      _impl_t(const _data_t& data) : _data(data)
      {
      }

      _data_t _data;
    };

    // Base template to be inherited by the statement
    template <typename Policies>
    struct _base_t
    {
      using _data_t = with_data_t<Database, Expressions...>;

      // workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
      template <typename... Args>
      _base_t(Args&&... args) : with{std::forward<Args>(args)...}
      {
      }

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

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

      // FIXME: Need real checks here
      using _consistency_check = consistent_t;
    };
  };

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

    // Data
    using _data_t = no_data_t;

    // Member implementation with data and methods
    template <typename Policies>
    struct _impl_t
    {
      // workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
      _impl_t() = default;
      _impl_t(const _data_t& data) : _data(data)
      {
      }

      _data_t _data;
    };

    // Base template to be inherited by the statement
    template <typename Policies>
    struct _base_t
    {
      using _data_t = no_data_t;

      // workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
      template <typename... Args>
      _base_t(Args&&... args) : no_with{std::forward<Args>(args)...}
      {
      }

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

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

      using _consistency_check = consistent_t;
    };
  };

  template <typename Database, typename... Expressions>
  struct blank_with_t
  {
    with_data_t<Database, Expressions...> _data;

    template <typename Statement>
    auto operator()(Statement statement)
        -> new_statement_t<consistent_t, typename Statement::_policies_t, no_with_t, with_t<Database, Expressions...>>
    {
      // FIXME need checks here
      //       check that no cte refers to any of the ctes to the right
      return {statement, _data};
    }
  };

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

    static Context& _(const T& t, Context& context)
    {
      // FIXME: If there is a recursive CTE, add a "RECURSIVE" here
      context << " WITH ";
      if (T::_is_recursive::value)
        context << "RECURSIVE ";
      interpret_tuple(t._expressions, ',', context);
      context << ' ';
      return context;
    }
  };

  template <typename... Expressions>
  auto with(Expressions... cte) -> blank_with_t<void, Expressions...>
  {
    static_assert(logic::all_t<is_cte_t<Expressions>::value...>::value,
                  "at least one expression in with is not a common table expression");
    static_assert(logic::none_t<is_alias_t<Expressions>::value...>::value,
                  "at least one expression in with is an incomplete common table expression");
    return {{cte...}};
  }
}

#endif