~drizzle-trunk/drizzle/development

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

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

 *

 *  Copyright (C) 2009 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; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  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 "config.h"

#include <assert.h>

#include "drizzled/table_identifier.h"

#include "drizzled/session.h"

#include "drizzled/current_session.h"

#include "drizzled/internal/my_sys.h"

#include "drizzled/data_home.h"

#include <algorithm>

#include <sstream>

using namespace std;

namespace drizzled

{

extern char *drizzle_tmpdir;

extern pid_t current_pid;

static const char hexchars[]= "0123456789abcdef";

/*

  Translate a cursor name to a table name (WL #1324).

  SYNOPSIS

    filename_to_tablename()

      from                      The cursor name

      to                OUT     The table name

      to_length                 The size of the table name buffer.

  RETURN

    Table name length.

*/

uint32_t filename_to_tablename(const char *from, char *to, uint32_t to_length)

{

  uint32_t length= 0;

  if (!memcmp(from, TMP_FILE_PREFIX, TMP_FILE_PREFIX_LENGTH))

  {

    /* Temporary table name. */

    length= strlen(strncpy(to, from, to_length));

  }

  else

  {

    for (; *from  && length < to_length; length++, from++)

    {

      if (*from != '@')

      {

        to[length]= *from;

        continue;

      }

      /* We've found an escaped char - skip the @ */

      from++;

      to[length]= 0;

      /* There will be a two-position hex-char version of the char */

      for (int x=1; x >= 0; x--)

      {

        if (*from >= '0' && *from <= '9')

          to[length] += ((*from++ - '0') << (4 * x));

        else if (*from >= 'a' && *from <= 'f')

          to[length] += ((*from++ - 'a' + 10) << (4 * x));

      }

      /* Backup because we advanced extra in the inner loop */

      from--;

    } 

  }

  return length;

}

/*

  Creates path to a cursor: drizzle_tmpdir/#sql1234_12_1.ext

  SYNOPSIS

   build_tmptable_filename()

     session                    The thread handle.

     buff                       Where to write result

     bufflen                    buff size

  NOTES

    Uses current_pid, thread_id, and tmp_table counter to create

    a cursor name in drizzle_tmpdir.

  RETURN

    path length on success, 0 on failure

*/

size_t build_tmptable_filename(char *buff, size_t bufflen)

{

  size_t length;

  ostringstream path_str, post_tmpdir_str;

  string tmp;

  Session *session= current_session;

  path_str << drizzle_tmpdir;

  post_tmpdir_str << "/" << TMP_FILE_PREFIX << current_pid;

  post_tmpdir_str << session->thread_id << session->tmp_table++;

  tmp= post_tmpdir_str.str();

  transform(tmp.begin(), tmp.end(), tmp.begin(), ::tolower);

  path_str << tmp;

  if (bufflen < path_str.str().length())

    length= 0;

  else

    length= internal::unpack_filename(buff, path_str.str().c_str());

  return length;

}

/*

  Creates path to a cursor: drizzle_data_dir/db/table.ext

  SYNOPSIS

   build_table_filename()

     buff                       Where to write result

                                This may be the same as table_name.

     bufflen                    buff size

     db                         Database name

     table_name                 Table name

     ext                        File extension.

     flags                      FN_FROM_IS_TMP or FN_TO_IS_TMP

                                table_name is temporary, do not change.

  NOTES

    Uses database and table name, and extension to create

    a cursor name in drizzle_data_dir. Database and table

    names are converted from system_charset_info into "fscs".

    Unless flags indicate a temporary table name.

    'db' is always converted.

    'ext' is not converted.

    The conversion suppression is required for ALTER Table. This

    statement creates intermediate tables. These are regular

    (non-temporary) tables with a temporary name. Their path names must

    be derivable from the table name. So we cannot use

    build_tmptable_filename() for them.

  RETURN

    path length on success, 0 on failure

*/

size_t build_table_filename(char *buff, size_t bufflen, const char *db, const char *table_name, bool is_tmp)

{

  char dbbuff[FN_REFLEN];

  char tbbuff[FN_REFLEN];

  bool conversion_error= false;

  memset(tbbuff, 0, sizeof(tbbuff));

  if (is_tmp) // FN_FROM_IS_TMP | FN_TO_IS_TMP

    strncpy(tbbuff, table_name, sizeof(tbbuff));

  else

  {

    conversion_error= tablename_to_filename(table_name, tbbuff, sizeof(tbbuff));

    if (conversion_error)

    {

      errmsg_printf(ERRMSG_LVL_ERROR,

                    _("Table name cannot be encoded and fit within filesystem "

                      "name length restrictions."));

      return 0;

    }

  }

  memset(dbbuff, 0, sizeof(dbbuff));

  conversion_error= tablename_to_filename(db, dbbuff, sizeof(dbbuff));

  if (conversion_error)

  {

    errmsg_printf(ERRMSG_LVL_ERROR,

                  _("Schema name cannot be encoded and fit within filesystem "

                    "name length restrictions."));

    return 0;

  }

  int rootdir_len= strlen(FN_ROOTDIR);

  string table_path(drizzle_data_home);

  int without_rootdir= table_path.length()-rootdir_len;

  /* Don't add FN_ROOTDIR if dirzzle_data_home already includes it */

  if (without_rootdir >= 0)

  {

    const char *tmp= table_path.c_str()+without_rootdir;

    if (memcmp(tmp, FN_ROOTDIR, rootdir_len) != 0)

      table_path.append(FN_ROOTDIR);

  }

  table_path.append(dbbuff);

  table_path.append(FN_ROOTDIR);

  table_path.append(tbbuff);

  if (bufflen < table_path.length())

    return 0;

  strcpy(buff, table_path.c_str());

  return table_path.length();

}

/*

  Translate a table name to a cursor name (WL #1324).

  SYNOPSIS

    tablename_to_filename()

      from                      The table name

      to                OUT     The cursor name

      to_length                 The size of the cursor name buffer.

  RETURN

    true if errors happen. false on success.

*/

bool tablename_to_filename(const char *from, char *to, size_t to_length)

{

  size_t length= 0;

  for (; *from  && length < to_length; length++, from++)

  {

    if ((*from >= '0' && *from <= '9') ||

        (*from >= 'A' && *from <= 'Z') ||

        (*from >= 'a' && *from <= 'z') ||

/* OSX defines an extra set of high-bit and multi-byte characters

   that cannot be used on the filesystem. Instead of trying to sort

   those out, we'll just escape encode all high-bit-set chars on OSX.

   It won't really hurt anything - it'll just make some filenames ugly. */

#if !defined(TARGET_OS_OSX)

        ((unsigned char)*from >= 128) ||

#endif

        (*from == '_') ||

        (*from == ' ') ||

        (*from == '-'))

    {

      to[length]= *from;

      continue;

    }

    if (length + 3 >= to_length)

      return true;

    /* We need to escape this char in a way that can be reversed */

    to[length++]= '@';

    to[length++]= hexchars[(*from >> 4) & 15];

    to[length]= hexchars[(*from) & 15];

  }

  if (internal::check_if_legal_tablename(to) &&

      length + 4 < to_length)

  {

    memcpy(to + length, "@@@", 4);

    length+= 3;

  }

  return false;

}

const char *TableIdentifier::getPath()

{

  if (! path_inited)

  {

    size_t path_length= 0;

    switch (type) {

    case STANDARD_TABLE:

      path_length= build_table_filename(path, sizeof(path),

                                        db, table_name,

                                        false);

      break;

    case INTERNAL_TMP_TABLE:

      path_length= build_table_filename(path, sizeof(path),

                                        db, table_name,

                                        true);

      break;

    case TEMP_TABLE:

      path_length= build_tmptable_filename(path, sizeof(path));

      break;

    case SYSTEM_TMP_TABLE:

      assert(0);

    }

    path_inited= true;

    assert(path_length); // TODO throw exception, this is a possibility

  }

  return path;

}

} /* namespace drizzled */