sqlpp11/include/sqlpp11/functions.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_FUNCTIONS_H
#define SQLPP_FUNCTIONS_H

#include <sqlpp11/parameter.h>
#include <sqlpp11/parameter_list.h>
#include <sqlpp11/data_types.h>
#include <sqlpp11/aggregate_functions.h>
#include <sqlpp11/in.h>
#include <sqlpp11/not_in.h>
#include <sqlpp11/is_null.h>
#include <sqlpp11/is_not_null.h>
#include <sqlpp11/exists.h>
#include <sqlpp11/any.h>
#include <sqlpp11/some.h>
#include <sqlpp11/value_type.h>
#include <sqlpp11/verbatim.h>  // Csaba Csoma suggests: unsafe_sql instead of verbatim
#include <sqlpp11/verbatim_table.h>
#include <sqlpp11/value_or_null.h>
#include <sqlpp11/eval.h>

namespace sqlpp
{
  template <typename T>
  auto value(T t) -> wrap_operand_t<T>
  {
    static_assert(is_wrapped_value_t<wrap_operand_t<T>>::value,
                  "value() is to be called with non-sql-type like int, or string");
    return {t};
  }

  template <typename Expression, typename Db>
  auto flatten(const Expression& exp, Db& db) -> verbatim_t<value_type_of<Expression>>
  {
    static_assert(not make_parameter_list_t<Expression>::size::value,
                  "parameters are not allowed in flattened expressions");
    auto context = db.get_serializer_context();
    serialize(exp, context);
    return {context.str()};
  }

  template <typename Expression>
  auto is_null(Expression e) -> decltype(e.is_null())
  {
    return e.is_null();
  }

  template <typename Expression>
  auto is_not_null(Expression e) -> decltype(e.is_not_null())
  {
    return e.is_not_null();
  }

  template <typename Container>
  struct value_list_t  // to be used in .in() method
  {
    using _traits = make_traits<value_type_t<typename Container::value_type>, tag::is_expression>;
    using _nodes = detail::type_vector<>;

    using _container_t = Container;

    value_list_t(_container_t container) : _container(container)
    {
    }

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

    _container_t _container;
  };

  template <typename Context, typename Container>
  struct serializer_t<Context, value_list_t<Container>>
  {
    using _serialize_check = serialize_check_of<Context, wrap_operand_t<typename Container::value_type>>;
    using T = value_list_t<Container>;

    static Context& _(const T& t, Context& context)
    {
      if (t._container.size() == 1)
      {
        return serialize(value(*begin(t._container)), context);
      }

      bool first = true;
      for (const auto& entry : t._container)
      {
        if (first)
          first = false;
        else
          context << ',';

        serialize_operand(value(entry), context);
      }
      return context;
    }
  };

  template <typename Container>
  auto value_list(Container c) -> value_list_t<Container>
  {
    static_assert(
        is_wrapped_value_t<wrap_operand_t<typename Container::value_type>>::value,
        "value_list() is to be called with a container of non-sql-type like std::vector<int>, or std::list(string)");
    return {c};
  }

  template <typename T>
  constexpr const char* get_sql_name(const T&)
  {
    return name_of<T>::char_ptr();
  }
}

#endif