/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 *
 *  Copyright (C) 2008 Sun Microsystems, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef DRIZZLED_PLUGIN_FUNCTION_H
#define DRIZZLED_PLUGIN_FUNCTION_H


#include <drizzled/item/func.h>
#include <drizzled/plugin.h>
#include <drizzled/plugin/plugin.h>

#include <string>
#include <vector>
#include <functional>

#include <boost/unordered_map.hpp>

#include <drizzled/visibility.h>

namespace drizzled
{

class Item_func;

namespace memory
{
  class Root;
}

namespace util
{
struct insensitive_hash;
struct insensitive_equal_to;
}

namespace plugin
{

/**
 * Functions in the server: AKA UDF
 */
class DRIZZLED_API Function
  : public Plugin,
    public std::unary_function<memory::Root*, Item_func *>
{
  Function();
  Function(const Function &);
  Function& operator=(const Function &);
public:
  Function(std::string in_name)
   : Plugin(in_name, "Function"),
     std::unary_function<memory::Root*, Item_func *>()
  { }
  virtual result_type operator()(argument_type root) const= 0;
  virtual ~Function() {}

  /**
   * Add a new Function factory to the list of factories we manage.
   */
  static bool addPlugin(const plugin::Function *function_obj);

  /**
   * Remove a Function factory from the list of factory we manage.
   */
  static void removePlugin(const plugin::Function *function_obj);

  static const plugin::Function *get(const std::string &name);

  typedef boost::unordered_map<std::string, const plugin::Function *, util::insensitive_hash, util::insensitive_equal_to> UdfMap;
  typedef boost::unordered_map<std::string, const plugin::Function *, util::insensitive_hash, util::insensitive_equal_to> Map;

  static const UdfMap &getMap();
};

template<class T>
class Create_function
 : public Function
{
public:
  typedef T FunctionClass;
  Create_function(std::string in_name)
    : Function(in_name)
  { }
  virtual result_type operator()(argument_type root) const
  {
    return new (root) FunctionClass();
  }
};

} /* namespace plugin */
} /* namespace drizzled */


#endif /* DRIZZLED_PLUGIN_FUNCTION_H */
