~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

 */

#ifndef DRIZZLED_STORED_KEY_H

#define DRIZZLED_STORED_KEY_H

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

class StoredKey :public Sql_alloc

{

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)

    :

      null_key(0), 

      null_ptr(null), 

      err(0)

  {

    if (field_arg->type() == DRIZZLE_TYPE_BLOB)

    {

      /*

        Key segments are always packed with a 2 byte length prefix.

        See mi_rkey for details.

      */

      to_field= new Field_varstring(ptr, length, 2, null, 1,

                                    Field::NONE, field_arg->field_name,

                                    field_arg->table->s, field_arg->charset());

      to_field->init(field_arg->table);

    }

    else

      to_field= field_arg->new_key_field(session->mem_root, field_arg->table,

                                        ptr, null, 1);

    to_field->setWriteSet();

  }

  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()

  {

    enum store_key_result result;

    Session *session= to_field->table->in_use;

    enum_check_fields saved_count_cuted_fields= session->count_cuted_fields;

    session->count_cuted_fields= CHECK_FIELD_IGNORE;

    result= copy_inner();

    session->count_cuted_fields= saved_count_cuted_fields;

    return result;

  }

};

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);

  }

};

#endif /* DRIZZLED_STORED_KEY_H */