~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems

 *

 *  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

 */

#include <drizzled/server_includes.h>

#include <drizzled/error.h>

#include <drizzled/name_resolution_context.h>

#include <drizzled/table.h>

#include <drizzled/session.h>

#include <drizzled/current_session.h>

#include <drizzled/item/default_value.h>

bool Item_default_value::eq(const Item *item, bool binary_cmp) const

{

  return item->type() == DEFAULT_VALUE_ITEM &&

    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);

}

bool Item_default_value::fix_fields(Session *session, Item **)

{

  Item *real_arg;

  Item_field *field_arg;

  Field *def_field;

  assert(fixed == 0);

  if (!arg)

  {

    fixed= 1;

    return false;

  }

  if (!arg->fixed && arg->fix_fields(session, &arg))

    goto error;

  real_arg= arg->real_item();

  if (real_arg->type() != FIELD_ITEM)

  {

    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), arg->name);

    goto error;

  }

  field_arg= (Item_field *)real_arg;

  if (field_arg->field->flags & NO_DEFAULT_VALUE_FLAG)

  {

    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);

    goto error;

  }

  if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))

    goto error;

  memcpy(def_field, field_arg->field, field_arg->field->size_of());

  def_field->move_field_offset((my_ptrdiff_t)

                               (def_field->table->s->default_values -

                                def_field->table->record[0]));

  set_field(def_field);

  return false;

error:

  context->process_error(session);

  return true;

}

void Item_default_value::print(String *str, enum_query_type query_type)

{

  if (!arg)

  {

    str->append(STRING_WITH_LEN("default"));

    return;

  }

  str->append(STRING_WITH_LEN("default("));

  arg->print(str, query_type);

  str->append(')');

}

int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)

{

  if (!arg)

  {

    if (field_arg->flags & NO_DEFAULT_VALUE_FLAG)

    {

      if (field_arg->reset())

      {

        my_message(ER_CANT_CREATE_GEOMETRY_OBJECT,

                   ER(ER_CANT_CREATE_GEOMETRY_OBJECT), MYF(0));

        return -1;

      }

      {

        push_warning_printf(field_arg->table->in_use,

                            DRIZZLE_ERROR::WARN_LEVEL_WARN,

                            ER_NO_DEFAULT_FOR_FIELD,

                            ER(ER_NO_DEFAULT_FOR_FIELD),

                            field_arg->field_name);

      }

      return 1;

    }

    field_arg->set_default();

    return 0;

  }

  return Item_field::save_in_field(field_arg, no_conversions);

}

/**

  This method like the walk method traverses the item tree, but at the

  same time it can replace some nodes in the tree.

*/

Item *Item_default_value::transform(Item_transformer transformer, unsigned char *args)

{

  Item *new_item= arg->transform(transformer, args);

  if (!new_item)

    return NULL;

  /*

    Session::change_item_tree() should be called only if the tree was

    really transformed, i.e. when a new item has been created.

    Otherwise we'll be allocating a lot of unnecessary memory for

    change records at each execution.

  */

  if (arg != new_item)

    current_session->change_item_tree(&arg, new_item);

  return (this->*transformer)(args);

}