~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, 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

 */

#pragma once

#include <drizzled/memory/sql_alloc.h>

#include <drizzled/copy_field.h>

#include <drizzled/item.h>

namespace drizzled {

/** class to store an field/item as a key struct */

class StoredKey :public memory::SqlAlloc

{

public:

  bool null_key; /**< If true, the value of the key has a null part */

  enum store_key_result 

  { 

    STORE_KEY_OK,

    STORE_KEY_FATAL, 

    STORE_KEY_CONV 

  };

protected:

  Field *to_field;				// Store data here

  unsigned char *null_ptr;

  unsigned char err;

  virtual enum store_key_result copy_inner()=0;

public:

  StoredKey(Session *session,

            Field *field_arg, 

            unsigned char *ptr,

            unsigned char *null, 

            uint32_t length);

  virtual ~StoredKey() {}			/** Not actually needed */

  virtual const char *name() const=0;

  /**

    @brief sets ignore truncation warnings mode and calls the real copy method

    @details this function makes sure truncation warnings when preparing the

    key buffers don't end up as errors (because of an enclosing INSERT/UPDATE).

  */

  enum store_key_result copy();

};

class store_key_field: public StoredKey

{

  CopyField copy_field;

  const char *field_name;

public:

  store_key_field(Session *session, Field *to_field_arg, unsigned char *ptr,

                  unsigned char *null_ptr_arg,

                  uint32_t length, Field *from_field, const char *name_arg) :

    StoredKey(session, to_field_arg,ptr,

              null_ptr_arg ? null_ptr_arg : from_field->maybe_null() ? &err

              : (unsigned char*) 0, length), field_name(name_arg)

    {

    if (to_field)

    {

      copy_field.set(to_field,from_field,0);

    }

  }

  const char *name() const { return field_name; }

protected:

  enum store_key_result copy_inner()

  {

    copy_field.do_copy(&copy_field);

    null_key= to_field->is_null();

    return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK;

  }

};

class store_key_item :public StoredKey

{

protected:

  Item *item;

public:

  store_key_item(Session *session, Field *to_field_arg, unsigned char *ptr,

                 unsigned char *null_ptr_arg, uint32_t length, Item *item_arg) :

    StoredKey(session, to_field_arg, ptr,

	       null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?

	       &err : (unsigned char*) 0, length), item(item_arg)

  {}

  const char *name() const { return "func"; }

 protected:

  enum store_key_result copy_inner()

  {

    int res= item->save_in_field(to_field, 1);

    null_key= to_field->is_null() || item->null_value;

    return (err != 0 || res > 2 ? STORE_KEY_FATAL : (store_key_result) res);

  }

};

class store_key_const_item :public store_key_item

{

  bool inited;

public:

  store_key_const_item(Session *session, Field *to_field_arg, unsigned char *ptr,

                       unsigned char *null_ptr_arg, uint32_t length,

                       Item *item_arg) :

    store_key_item(session, to_field_arg,ptr,

                   null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?

                   &err : (unsigned char*) 0, length, item_arg), inited(0)

  {

  }

  const char *name() const { return "const"; }

protected:

  enum store_key_result copy_inner()

  {

    int res;

    if (!inited)

    {

      inited=1;

      if ((res= item->save_in_field(to_field, 1)))

      {

        if (!err)

          err= res;

      }

    }

    null_key= to_field->is_null() || item->null_value;

    return (err > 2 ?  STORE_KEY_FATAL : (store_key_result) err);

  }

};

} /* namespace drizzled */