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   1  <?php
   2  /**
   3   * Mssql search engine
   4   *
   5   * This program is free software; you can redistribute it and/or modify
   6   * it under the terms of the GNU General Public License as published by
   7   * the Free Software Foundation; either version 2 of the License, or
   8   * (at your option) any later version.
   9   *
  10   * This program is distributed in the hope that it will be useful,
  11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13   * GNU General Public License for more details.
  14   *
  15   * You should have received a copy of the GNU General Public License along
  16   * with this program; if not, write to the Free Software Foundation, Inc.,
  17   * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18   * http://www.gnu.org/copyleft/gpl.html
  19   *
  20   * @file
  21   * @ingroup Search
  22   */
  23  
  24  /**
  25   * Search engine hook base class for Mssql (ConText).
  26   * @ingroup Search
  27   */
  28  class SearchMssql extends SearchDatabase {
  29      /**
  30       * Perform a full text search query and return a result set.
  31       *
  32       * @param string $term Raw search term
  33       * @return SqlSearchResultSet
  34       * @access public
  35       */
  36  	function searchText( $term ) {
  37          $resultSet = $this->db->query( $this->getQuery( $this->filter( $term ), true ) );
  38          return new SqlSearchResultSet( $resultSet, $this->searchTerms );
  39      }
  40  
  41      /**
  42       * Perform a title-only search query and return a result set.
  43       *
  44       * @param string $term Raw search term
  45       * @return SqlSearchResultSet
  46       * @access public
  47       */
  48  	function searchTitle( $term ) {
  49          $resultSet = $this->db->query( $this->getQuery( $this->filter( $term ), false ) );
  50          return new SqlSearchResultSet( $resultSet, $this->searchTerms );
  51      }
  52  
  53      /**
  54       * Return a partial WHERE clause to limit the search to the given namespaces
  55       *
  56       * @return string
  57       * @private
  58       */
  59  	function queryNamespaces() {
  60          $namespaces = implode( ',', $this->namespaces );
  61          if ( $namespaces == '' ) {
  62              $namespaces = '0';
  63          }
  64          return 'AND page_namespace IN (' . $namespaces . ')';
  65      }
  66  
  67      /**
  68       * Return a LIMIT clause to limit results on the query.
  69       *
  70       * @param string $sql
  71       *
  72       * @return string
  73       */
  74  	function queryLimit( $sql ) {
  75          return $this->db->limitResult( $sql, $this->limit, $this->offset );
  76      }
  77  
  78      /**
  79       * Does not do anything for generic search engine
  80       * subclasses may define this though
  81       *
  82       * @param string $filteredTerm
  83       * @param bool $fulltext
  84       * @return string
  85       */
  86  	function queryRanking( $filteredTerm, $fulltext ) {
  87          return ' ORDER BY ftindex.[RANK] DESC'; // return ' ORDER BY score(1)';
  88      }
  89  
  90      /**
  91       * Construct the full SQL query to do the search.
  92       * The guts shoulds be constructed in queryMain()
  93       *
  94       * @param string $filteredTerm
  95       * @param bool $fulltext
  96       * @return string
  97       */
  98  	function getQuery( $filteredTerm, $fulltext ) {
  99          return $this->queryLimit( $this->queryMain( $filteredTerm, $fulltext ) . ' ' .
 100              $this->queryNamespaces() . ' ' .
 101              $this->queryRanking( $filteredTerm, $fulltext ) . ' ' );
 102      }
 103  
 104      /**
 105       * Picks which field to index on, depending on what type of query.
 106       *
 107       * @param bool $fulltext
 108       * @return string
 109       */
 110  	function getIndexField( $fulltext ) {
 111          return $fulltext ? 'si_text' : 'si_title';
 112      }
 113  
 114      /**
 115       * Get the base part of the search query.
 116       *
 117       * @param string $filteredTerm
 118       * @param bool $fulltext
 119       * @return string
 120       * @private
 121       */
 122  	function queryMain( $filteredTerm, $fulltext ) {
 123          $match = $this->parseQuery( $filteredTerm, $fulltext );
 124          $page = $this->db->tableName( 'page' );
 125          $searchindex = $this->db->tableName( 'searchindex' );
 126  
 127          return 'SELECT page_id, page_namespace, page_title, ftindex.[RANK]' .
 128              "FROM $page,FREETEXTTABLE($searchindex , $match, LANGUAGE 'English') as ftindex " .
 129              'WHERE page_id=ftindex.[KEY] ';
 130      }
 131  
 132      /** @todo document
 133       * @param string $filteredText
 134       * @param bool $fulltext
 135       * @return string
 136       */
 137  	function parseQuery( $filteredText, $fulltext ) {
 138          global $wgContLang;
 139          $lc = $this->legalSearchChars();
 140          $this->searchTerms = array();
 141  
 142          # @todo FIXME: This doesn't handle parenthetical expressions.
 143          $m = array();
 144          $q = array();
 145  
 146          if ( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 147              $filteredText, $m, PREG_SET_ORDER ) ) {
 148              foreach ( $m as $terms ) {
 149                  $q[] = $terms[1] . $wgContLang->normalizeForSearch( $terms[2] );
 150  
 151                  if ( !empty( $terms[3] ) ) {
 152                      $regexp = preg_quote( $terms[3], '/' );
 153                      if ( $terms[4] ) {
 154                          $regexp .= "[0-9A-Za-z_]+";
 155                      }
 156                  } else {
 157                      $regexp = preg_quote( str_replace( '"', '', $terms[2] ), '/' );
 158                  }
 159                  $this->searchTerms[] = $regexp;
 160              }
 161          }
 162  
 163          $searchon = $this->db->addQuotes( join( ',', $q ) );
 164          $field = $this->getIndexField( $fulltext );
 165          return "$field, $searchon";
 166      }
 167  
 168      /**
 169       * Create or update the search index record for the given page.
 170       * Title and text should be pre-processed.
 171       *
 172       * @param int $id
 173       * @param string $title
 174       * @param string $text
 175       * @return bool|ResultWrapper
 176       */
 177  	function update( $id, $title, $text ) {
 178          // We store the column data as UTF-8 byte order marked binary stream
 179          // because we are invoking the plain text IFilter on it so that, and we want it
 180          // to properly decode the stream as UTF-8.  SQL doesn't support UTF8 as a data type
 181          // but the indexer will correctly handle it by this method.  Since all we are doing
 182          // is passing this data to the indexer and never retrieving it via PHP, this will save space
 183          $table = $this->db->tableName( 'searchindex' );
 184          $utf8bom = '0xEFBBBF';
 185          $si_title = $utf8bom . bin2hex( $title );
 186          $si_text = $utf8bom . bin2hex( $text );
 187          $sql = "DELETE FROM $table WHERE si_page = $id;";
 188          $sql .= "INSERT INTO $table (si_page, si_title, si_text) VALUES ($id, $si_title, $si_text)";
 189          return $this->db->query( $sql, 'SearchMssql::update' );
 190      }
 191  
 192      /**
 193       * Update a search index record's title only.
 194       * Title should be pre-processed.
 195       *
 196       * @param int $id
 197       * @param string $title
 198       * @return bool|ResultWrapper
 199       */
 200  	function updateTitle( $id, $title ) {
 201          $table = $this->db->tableName( 'searchindex' );
 202  
 203          // see update for why we are using the utf8bom
 204          $utf8bom = '0xEFBBBF';
 205          $si_title = $utf8bom . bin2hex( $title );
 206          $sql = "DELETE FROM $table WHERE si_page = $id;";
 207          $sql .= "INSERT INTO $table (si_page, si_title, si_text) VALUES ($id, $si_title, 0x00)";
 208          return $this->db->query( $sql, 'SearchMssql::updateTitle' );
 209      }
 210  }