~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/dtcollation.h>

#include <drizzled/definitions.h>

#include <mysys/my_sys.h>

#include <mystrings/m_ctype.h>

#include <drizzled/error.h>

#include <drizzled/function/str/conv_charset.h>

#include <drizzled/session.h>

DTCollation::DTCollation()

{

  collation= &my_charset_bin;

  derivation= DERIVATION_NONE;

}

DTCollation::DTCollation(const CHARSET_INFO * const collation_arg,

                         Derivation derivation_arg)

{

  collation= collation_arg;

  derivation= derivation_arg;

}

void DTCollation::set(DTCollation &dt)

{

  collation= dt.collation;

  derivation= dt.derivation;

}

void DTCollation::set(const CHARSET_INFO * const collation_arg,

                      Derivation derivation_arg)

{

  collation= collation_arg;

  derivation= derivation_arg;

}

void DTCollation::set(const CHARSET_INFO * const collation_arg)

{

  collation= collation_arg;

}

void DTCollation::set(Derivation derivation_arg)

{

  derivation= derivation_arg;

}

bool DTCollation::aggregate(DTCollation &dt, uint32_t flags)

{

  if (!my_charset_same(collation, dt.collation))

  {

    /*

      We do allow to use binary strings (like BLOBS)

      together with character strings.

      Binaries have more precedence than a character

      string of the same derivation.

    */

    if (collation == &my_charset_bin)

    {

      if (derivation <= dt.derivation)

        ; // Do nothing

      else

      {

        set(dt);

      }

    }

    else if (dt.collation == &my_charset_bin)

    {

      if (dt.derivation <= derivation)

      {

        set(dt);

      }

      else

      {

        // Do nothing

      }

    }

    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&

             collation->state & MY_CS_UNICODE &&

             (derivation < dt.derivation ||

              (derivation == dt.derivation &&

               !(dt.collation->state & MY_CS_UNICODE))))

    {

      // Do nothing

    }

    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&

             dt.collation->state & MY_CS_UNICODE &&

             (dt.derivation < derivation ||

              (dt.derivation == derivation &&

               !(collation->state & MY_CS_UNICODE))))

    {

      set(dt);

    }

    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&

             derivation < dt.derivation &&

             dt.derivation >= DERIVATION_SYSCONST)

    {

      // Do nothing;

    }

    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&

             dt.derivation < derivation &&

             derivation >= DERIVATION_SYSCONST)

    {

      set(dt);

    }

    else

    {

      // Cannot apply conversion

      set(0, DERIVATION_NONE);

      return true;

    }

  }

  else if (derivation < dt.derivation)

  {

    // Do nothing

  }

  else if (dt.derivation < derivation)

  {

    set(dt);

  }

  else

  {

    if (collation == dt.collation)

    {

      // Do nothing

    }

    else

    {

      if (derivation == DERIVATION_EXPLICIT)

      {

        set(0, DERIVATION_NONE);

        return true;

      }

      if (collation->state & MY_CS_BINSORT)

        return false;

      if (dt.collation->state & MY_CS_BINSORT)

      {

        set(dt);

        return false;

      }

      const CHARSET_INFO * const bin= get_charset_by_csname(collation->csname, MY_CS_BINSORT);

      set(bin, DERIVATION_NONE);

    }

  }

  return false;

}

bool DTCollation::set(DTCollation &dt1, DTCollation &dt2, uint32_t flags)

{ set(dt1); return aggregate(dt2, flags); }

const char *DTCollation::derivation_name() const

{

  switch(derivation)

  {

  case DERIVATION_IGNORABLE: return "IGNORABLE";

  case DERIVATION_COERCIBLE: return "COERCIBLE";

  case DERIVATION_IMPLICIT:  return "IMPLICIT";

  case DERIVATION_SYSCONST:  return "SYSCONST";

  case DERIVATION_EXPLICIT:  return "EXPLICIT";

  case DERIVATION_NONE:      return "NONE";

  default: return "UNKNOWN";

  }

}

bool agg_item_collations(DTCollation &c, const char *fname,

                         Item **av, uint32_t count,

                         uint32_t flags, int item_sep)

{

  uint32_t i;

  Item **arg;

  c.set(av[0]->collation);

  for (i= 1, arg= &av[item_sep]; i < count; i++, arg++)

  {

    if (c.aggregate((*arg)->collation, flags))

    {

      my_coll_agg_error(av, count, fname, item_sep);

      return true;

    }

  }

  if ((flags & MY_COLL_DISALLOW_NONE) &&

      c.derivation == DERIVATION_NONE)

  {

    my_coll_agg_error(av, count, fname, item_sep);

    return true;

  }

  return false;

}

bool agg_item_collations_for_comparison(DTCollation &c, const char *fname,

                                        Item **av, uint32_t count,

                                        uint32_t flags)

{

  return (agg_item_collations(c, fname, av, count,

                              flags | MY_COLL_DISALLOW_NONE, 1));

}

bool agg_item_charsets(DTCollation &coll, const char *fname,

                       Item **args, uint32_t nargs, uint32_t flags,

                       int item_sep)

{

  Item **arg, *safe_args[2];

  memset(safe_args, 0, sizeof(safe_args));

  if (agg_item_collations(coll, fname, args, nargs, flags, item_sep))

    return true;

  /*

    For better error reporting: save the first and the second argument.

    We need this only if the the number of args is 3 or 2:

    - for a longer argument list, "Illegal mix of collations"

      doesn't display each argument's characteristics.

    - if nargs is 1, then this error cannot happen.

  */

  if (nargs >=2 && nargs <= 3)

  {

    safe_args[0]= args[0];

    safe_args[1]= args[item_sep];

  }

  Session *session= current_session;

  bool res= false;

  uint32_t i;

  for (i= 0, arg= args; i < nargs; i++, arg+= item_sep)

  {

    Item* conv;

    uint32_t dummy_offset;

    if (!String::needs_conversion(0, (*arg)->collation.collation,

                                  coll.collation,

                                  &dummy_offset))

      continue;

    if (!(conv= (*arg)->safe_charset_converter(coll.collation)))

    {

      if (nargs >=2 && nargs <= 3)

      {

        /* restore the original arguments for better error message */

        args[0]= safe_args[0];

        args[item_sep]= safe_args[1];

      }

      my_coll_agg_error(args, nargs, fname, item_sep);

      res= true;

      break; // we cannot return here, we need to restore "arena".

    }

    if ((*arg)->type() == Item::FIELD_ITEM)

      ((Item_field *)(*arg))->no_const_subst= 1;

    /*

      If in statement prepare, then we create a converter for two

      constant items, do it once and then reuse it.

      If we're in execution of a prepared statement, arena is NULL,

      and the conv was created in runtime memory. This can be

      the case only if the argument is a parameter marker ('?'),

      because for all true constants the charset converter has already

      been created in prepare. In this case register the change for

      rollback.

    */

    session->change_item_tree(arg, conv);

    /*

      We do not check conv->fixed, because Item_func_conv_charset which can

      be return by safe_charset_converter can't be fixed at creation

    */

    conv->fix_fields(session, arg);

  }

  return res;

}

void my_coll_agg_error(DTCollation &c1,

                       DTCollation &c2, const char *fname)

{

  my_error(ER_CANT_AGGREGATE_2COLLATIONS,MYF(0),

           c1.collation->name,c1.derivation_name(),

           c2.collation->name,c2.derivation_name(),

           fname);

}

void my_coll_agg_error(DTCollation &c1,

                       DTCollation &c2,

                       DTCollation &c3,

                       const char *fname)

{

  my_error(ER_CANT_AGGREGATE_3COLLATIONS,MYF(0),

           c1.collation->name,c1.derivation_name(),

           c2.collation->name,c2.derivation_name(),

           c3.collation->name,c3.derivation_name(),

           fname);

}

void my_coll_agg_error(Item** args, uint32_t count, const char *fname,

                       int item_sep)

{

  if (count == 2)

    my_coll_agg_error(args[0]->collation, args[item_sep]->collation, fname);

  else if (count == 3)

    my_coll_agg_error(args[0]->collation, args[item_sep]->collation,

                      args[2*item_sep]->collation, fname);

  else

    my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),fname);

}