includes/SearchEngine.php

   1 <?php
   2 /**
   3  * Contain site class
   4  * See search.doc
   5  * @package MediaWiki
   6  */
   7
   8 /**
   9  *
  10  */
  11 define( 'MW_SEARCH_OK', true );
  12 define( 'MW_SEARCH_BAD_QUERY', false );
  13
  14 /**
  15  * @todo document
  16  * @package MediaWiki
  17  */
  18 class SearchEngine {
  19         /* private */ var $rawText, $filteredText, $searchTerms;
  20         /* private */ var $titleCond, $textCond;
  21
  22         var $doSearchRedirects = true;
  23         var $addToQuery = array();
  24         var $namespacesToSearch = array();
  25         var $alternateTitle;
  26         var $allTitles = false;
  27
  28         function SearchEngine( $text ) {
  29                 $this->rawText = trim( $text );
  30
  31                 # We display the query, so let's strip it for safety
  32                 #
  33                 global $wgDBmysql4;
  34                 $lc = SearchEngine::legalSearchChars() . '()';
  35                 if( $wgDBmysql4 ) {
  36                         $lc .= "\"~<>*+-";
  37                 }
  38                 $this->filteredText = trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  39                 $this->searchTerms = array();
  40                 $this->strictMatching = true; # Google-style, add '+' on all terms
  41
  42                 $this->db =& wfGetDB( DB_SLAVE );
  43         }
  44
  45         /**
  46          * Return a partial WHERE clause to limit the search to the given namespaces
  47          */
  48         function queryNamespaces() {
  49                 $namespaces = implode( ',', $this->namespacesToSearch );
  50                 if ($namespaces == '') {
  51                         $namespaces = '0';
  52                 }
  53                 return "AND cur_namespace IN (" . $namespaces . ')';
  54         }
  55
  56         /**
  57          * Return a partial WHERE clause to include or exclude redirects from results
  58          */
  59         function searchRedirects() {
  60                 if ( $this->doSearchRedirects ) {
  61                         return '';
  62                 } else {
  63                         return 'AND cur_is_redirect=0 ';
  64                 }
  65         }
  66
  67         /**
  68          * @access private
  69          */ function initNamespaceCheckbox( $i ) {
  70                 global $wgUser, $wgNamespacesToBeSearchedDefault;
  71
  72                 if ($wgUser->getID()) {
  73                         // User is logged in so we retrieve his default namespaces
  74                         return $wgUser->getOption( 'searchNs'.$i );
  75                 } else {
  76                         // User is not logged in so we give him the global default namespaces
  77                         return !empty($wgNamespacesToBeSearchedDefault[ $i ]);
  78                 }
  79         }
  80
  81         /**
  82          * Display the "power search" footer. Does not actually perform the search,
  83          * that is done by showResults()
  84          */
  85         function powersearch() {
  86                 global $wgUser, $wgOut, $wgContLang, $wgTitle, $wgRequest;
  87                 $sk =& $wgUser->getSkin();
  88
  89                 $search                 = $this->rawText;
  90                 $searchx                = $wgRequest->getVal( 'searchx' );
  91                 $listredirs             = $wgRequest->getVal( 'redirs' );
  92
  93                 $ret = wfMsg('powersearchtext'); # Text to be returned
  94                 $tempText = ''; # Temporary text, for substitution into $ret
  95
  96                 if( isset( $_REQUEST['searchx'] ) ) {
  97                         $this->addToQuery['searchx'] = '1';
  98                 }
  99
 100                 # Do namespace checkboxes
 101                 $namespaces = $wgContLang->getNamespaces();
 102                 foreach ( $namespaces as $i => $namespace ) {
 103                         # Skip virtual namespaces
 104                         if ( $i < 0 ) {
 105                                 continue;
 106                         }
 107
 108                         $formVar = 'ns'.$i;
 109
 110                         # Initialise checkboxValues, either from defaults or from
 111                         # a previous invocation
 112                         if ( !isset( $searchx ) ) {
 113                                 $checkboxValue = $this->initNamespaceCheckbox( $i );
 114                         } else {
 115                                 $checkboxValue = $wgRequest->getVal( $formVar );
 116                         }
 117
 118                         $checked = '';
 119                         if ( $checkboxValue == 1 ) {
 120                                 $checked = ' checked="checked"';
 121                                 $this->addToQuery['ns'.$i] = 1;
 122                                 array_push( $this->namespacesToSearch, $i );
 123                         }
 124                         $name = str_replace( '_', ' ', $namespaces[$i] );
 125                         if ( '' == $name ) {
 126                                 $name = wfMsg( 'blanknamespace' );
 127                         }
 128
 129                         if ( $tempText !== '' ) {
 130                                 $tempText .= ' ';
 131                         }
 132                         $tempText .= "<input type='checkbox' value=\"1\" name=\"" .
 133                           "ns{$i}\"{$checked} />{$name}\n";
 134                 }
 135                 $ret = str_replace ( '$1', $tempText, $ret );
 136
 137                 # List redirects checkbox
 138
 139                 $checked = '';
 140                 if ( $listredirs == 1 ) {
 141                         $this->addToQuery['redirs'] = 1;
 142                         $checked = ' checked="checked"';
 143                 }
 144                 $tempText = "<input type='checkbox' value='1' name=\"redirs\"{$checked} />\n";
 145                 $ret = str_replace( '$2', $tempText, $ret );
 146
 147                 # Search field
 148
 149                 $tempText = "<input type='text' name=\"search\" value=\"" .
 150                         htmlspecialchars( $search ) ."\" width=\"80\" />\n";
 151         $ret = str_replace( "$3", $tempText, $ret );
 152
 153                 # Searchx button
 154
 155                 $tempText = '<input type="submit" name="searchx" value="' .
 156                   wfMsg('powersearch') . "\" />\n";
 157                 $ret = str_replace( '$9', $tempText, $ret );
 158
 159                 $action = $sk->escapeSearchLink();
 160                 $ret = "<br /><br />\n<form id=\"powersearch\" method=\"get\" " .
 161                   "action=\"$action\">\n{$ret}\n</form>\n";
 162
 163                 if ( isset ( $searchx ) ) {
 164                         if ( ! $listredirs ) {
 165                                 $this->doSearchRedirects = false;
 166                         }
 167                 }
 168                 return $ret;
 169         }
 170
 171         function setupPage() {
 172                 global $wgOut;
 173                 $wgOut->setPageTitle( wfMsg( 'searchresults' ) );
 174                 $wgOut->setSubtitle( wfMsg( 'searchquery', htmlspecialchars( $this->rawText ) ) );
 175                 $wgOut->setArticleRelated( false );
 176                 $wgOut->setRobotpolicy( 'noindex,nofollow' );
 177         }
 178
 179         /**
 180          * Perform the search and construct the results page
 181          */
 182         function showResults() {
 183                 global $wgUser, $wgTitle, $wgOut, $wgLang;
 184                 global $wgDisableTextSearch, $wgInputEncoding;
 185                 $fname = 'SearchEngine::showResults';
 186
 187                 $search = $this->rawText;
 188
 189                 $powersearch = $this->powersearch(); /* Need side-effects here? */
 190
 191                 $this->setupPage();
 192
 193                 $sk = $wgUser->getSkin();
 194                 $wgOut->addWikiText( wfMsg( 'searchresulttext' ) );
 195
 196                 if ( !$this->parseQuery() ) {
 197                         $wgOut->addWikiText(
 198                                 '==' . wfMsg( 'badquery' ) . "==\n" .
 199                                 wfMsg( 'badquerytext' ) );
 200                         return;
 201                 }
 202                 list( $limit, $offset ) = wfCheckLimits( 20, 'searchlimit' );
 203
 204                 if ( $wgDisableTextSearch ) {
 205                         $wgOut->addHTML( wfMsg( 'searchdisabled' ) );
 206                         $wgOut->addHTML( wfMsg( 'googlesearch',
 207                                 htmlspecialchars( $this->rawText ),
 208                                 htmlspecialchars( $wgInputEncoding ) ) );
 209                         return;
 210                 }
 211
 212                 $titleMatches = $this->getMatches( $this->titleCond, $limit, $offset );
 213                 $textMatches = $this->getMatches( $this->textCond, $limit, $offset );
 214
 215                 $sk = $wgUser->getSkin();
 216
 217                 $num = count( $titleMatches ) + count( $textMatches );
 218                 if ( $num >= $limit ) {
 219                         $top = wfShowingResults( $offset, $limit );
 220                 } else {
 221                         $top = wfShowingResultsNum( $offset, $limit, $num );
 222                 }
 223                 $wgOut->addHTML( "<p>{$top}</p>\n" );
 224
 225                 # For powersearch
 226                 $a2l = '';
 227                 $akk = array_keys( $this->addToQuery );
 228                 foreach ( $akk AS $ak ) {
 229                         $a2l .= "&{$ak}={$this->addToQuery[$ak]}" ;
 230                 }
 231
 232                 $prevnext = wfViewPrevNext( $offset, $limit, 'Special:Search',
 233                   'search=' . wfUrlencode( $this->filteredText ) . $a2l );
 234                 $wgOut->addHTML( "<br />{$prevnext}\n" );
 235
 236                 $foundsome = $this->showMatches( $titleMatches, $offset, 'notitlematches', 'titlematches' )
 237                                   || $this->showMatches( $textMatches,  $offset, 'notextmatches',  'textmatches'  );
 238
 239                 if ( !$foundsome ) {
 240                         $wgOut->addWikiText( wfMsg( 'nonefound' ) );
 241                 }
 242                 $wgOut->addHTML( "<p>{$prevnext}</p>\n" );
 243                 $wgOut->addHTML( $powersearch );
 244         }
 245
 246         function legalSearchChars() {
 247                 $lc = "A-Za-z_'0-9\\x80-\\xFF\\-";
 248                 return $lc;
 249         }
 250
 251         function parseQuery() {
 252                 global $wgDBmysql4;
 253                 if (strlen($this->filteredText) < 1)
 254                         return MW_SEARCH_BAD_QUERY;
 255
 256                 if( $wgDBmysql4 ) {
 257                         # Use cleaner boolean search if available
 258                         return $this->parseQuery4();
 259                 } else {
 260                         # Fall back to ugly hack with multiple search clauses
 261                         return $this->parseQuery3();
 262                 }
 263         }
 264
 265         function parseQuery3() {
 266                 global $wgDBminWordLen, $wgContLang;
 267
 268                 # on non mysql4 database: get list of words we don't want to search for
 269                 require_once( 'FulltextStoplist.php' );
 270
 271                 $lc = SearchEngine::legalSearchChars() . '()';
 272                 $q = preg_replace( "/([()])/", " \\1 ", $this->filteredText );
 273                 $q = preg_replace( "/\\s+/", " ", $q );
 274                 $w = explode( ' ', trim( $q ) );
 275
 276                 $last = $cond = '';
 277                 foreach ( $w as $word ) {
 278                         $word = $wgContLang->stripForSearch( $word );
 279                         if ( 'and' == $word || 'or' == $word || 'not' == $word
 280                           || '(' == $word || ')' == $word ) {
 281                                 $cond .= ' ' . strtoupper( $word );
 282                                 $last = '';
 283                         } else if ( strlen( $word ) < $wgDBminWordLen ) {
 284                                 continue;
 285                         } else if ( FulltextStoplist::inList( $word ) ) {
 286                                 continue;
 287                         } else {
 288                                 if ( '' != $last ) { $cond .= ' AND'; }
 289                                 $cond .= " (MATCH (##field##) AGAINST ('" .
 290                                   $this->db->strencode( $word ). "'))";
 291                                 $last = $word;
 292                                 array_push( $this->searchTerms, "\\b" . $word . "\\b" );
 293                         }
 294                 }
 295                 if ( 0 == count( $this->searchTerms ) ) {
 296                         return MW_SEARCH_BAD_QUERY;
 297                 }
 298
 299                 $this->titleCond = '(' . str_replace( '##field##',
 300                   'si_title', $cond ) . ' )';
 301
 302                 $this->textCond = '(' . str_replace( '##field##',
 303                   'si_text', $cond ) . ' AND (cur_is_redirect=0) )';
 304
 305                 return MW_SEARCH_OK;
 306         }
 307
 308         function parseQuery4() {
 309                 global $wgContLang;
 310                 $lc = SearchEngine::legalSearchChars();
 311                 $searchon = '';
 312                 $this->searchTerms = array();
 313
 314                 # FIXME: This doesn't handle parenthetical expressions.
 315                 if( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 316                           $this->filteredText, $m, PREG_SET_ORDER ) ) {
 317                         foreach( $m as $terms ) {
 318                                 if( $searchon !== '' ) $searchon .= ' ';
 319                                 if( $this->strictMatching && ($terms[1] == '') ) {
 320                                         $terms[1] = '+';
 321                                 }
 322                                 $searchon .= $terms[1] . $wgContLang->stripForSearch( $terms[2] );
 323                                 if( !empty( $terms[3] ) ) {
 324                                         $regexp = preg_quote( $terms[3] );
 325                                         if( $terms[4] ) $regexp .= "[0-9A-Za-z_]+";
 326                                 } else {
 327                                         $regexp = preg_quote( str_replace( '"', '', $terms[2] ) );
 328                                 }
 329                                 $this->searchTerms[] = $regexp;
 330                         }
 331                         wfDebug( "Would search with '$searchon'\n" );
 332                         wfDebug( "Match with /\b" . implode( '\b|\b', $this->searchTerms ) . "\b/\n" );
 333                 } else {
 334                         wfDebug( "Can't understand search query '{$this->filteredText}'\n" );
 335                 }
 336
 337                 $searchon = $this->db->strencode( $searchon );
 338                 $this->titleCond = " MATCH(si_title) AGAINST('$searchon' IN BOOLEAN MODE)";
 339                 $this->textCond = " (MATCH(si_text) AGAINST('$searchon' IN BOOLEAN MODE) AND cur_is_redirect=0)";
 340                 return MW_SEARCH_OK;
 341         }
 342
 343         function &getMatches( $cond, $limit, $offset = 0 ) {
 344                 $searchindex = $this->db->tableName( 'searchindex' );
 345                 $cur = $this->db->tableName( 'cur' );
 346                 $searchnamespaces = $this->queryNamespaces();
 347                 $redircond = $this->searchRedirects();
 348
 349                 $sql = "SELECT cur_id,cur_namespace,cur_title," .
 350                   "cur_text FROM $cur,$searchindex " .
 351                   "WHERE cur_id=si_page AND {$cond} " .
 352                   "{$searchnamespaces} {$redircond} " .
 353                   $this->db->limitResult( $limit, $offset );
 354
 355                 $res = $this->db->query( $sql, 'SearchEngine::getMatches' );
 356                 $matches = array();
 357                 while ( $row = $this->db->fetchObject( $res ) ) {
 358                         $matches[] = $row;
 359                 }
 360                 $this->db->freeResult( $res );
 361
 362                 return $matches;
 363         }
 364
 365         function showMatches( &$matches, $offset, $msgEmpty, $msgFound ) {
 366                 global $wgOut;
 367                 if ( 0 == count( $matches ) ) {
 368                         $wgOut->addHTML( "<h2>" . wfMsg( $msgEmpty ) .
 369                           "</h2>\n" );
 370                         return false;
 371                 } else {
 372                         $off = $offset + 1;
 373                         $wgOut->addHTML( "<h2>" . wfMsg( $msgFound ) .
 374                           "</h2>\n<ol start='{$off}'>" );
 375
 376                         foreach( $matches as $row ) {
 377                                 $this->showHit( $row );
 378                         }
 379                         $wgOut->addHTML( "</ol>\n" );
 380                         return true;
 381                 }
 382         }
 383
 384         function showHit( $row ) {
 385                 global $wgUser, $wgOut, $wgContLang;
 386
 387                 $t = Title::makeName( $row->cur_namespace, $row->cur_title );
 388                 if( is_null( $t ) ) {
 389                         $wgOut->addHTML( "<!-- Broken link in search result -->\n" );
 390                         return;
 391                 }
 392                 $sk = $wgUser->getSkin();
 393
 394                 $contextlines = $wgUser->getOption( 'contextlines' );
 395                 if ( '' == $contextlines ) { $contextlines = 5; }
 396                 $contextchars = $wgUser->getOption( 'contextchars' );
 397                 if ( '' == $contextchars ) { $contextchars = 50; }
 398
 399                 $link = $sk->makeKnownLink( $t, '' );
 400                 $size = wfMsg( 'nbytes', strlen( $row->cur_text ) );
 401                 $wgOut->addHTML( "<li>{$link} ({$size})" );
 402
 403                 $lines = explode( "\n", $row->cur_text );
 404                 $pat1 = "/(.*)(" . implode( "|", $this->searchTerms ) . ")(.*)/i";
 405                 $lineno = 0;
 406
 407                 foreach ( $lines as $line ) {
 408                         if ( 0 == $contextlines ) {
 409                                 break;
 410                         }
 411                         --$contextlines;
 412                         ++$lineno;
 413                         if ( ! preg_match( $pat1, $line, $m ) ) {
 414                                 continue;
 415                         }
 416
 417                         $pre = $wgContLang->truncate( $m[1], -$contextchars, '...' );
 418
 419                         if ( count( $m ) < 3 ) {
 420                                 $post = '';
 421                         } else {
 422                                 $post = $wgContLang->truncate( $m[3], $contextchars, '...' );
 423                         }
 424
 425                         $found = $m[2];
 426
 427                         $line = htmlspecialchars( $pre . $found . $post );
 428                         $pat2 = '/(' . implode( '|', $this->searchTerms ) . ")/i";
 429                         $line = preg_replace( $pat2,
 430                           "<span class='searchmatch'>\\1</span>", $line );
 431
 432                         $wgOut->addHTML( "<br /><small>{$lineno}: {$line}</small>\n" );
 433                 }
 434                 $wgOut->addHTML( "</li>\n" );
 435         }
 436
 437         function getNearMatch() {
 438                 # Exact match? No need to look further.
 439                 $title = Title::newFromText( $this->rawText );
 440                 if ( $title->getNamespace() == NS_SPECIAL || 0 != $title->getArticleID() ) {
 441                         return $title;
 442                 }
 443
 444                 # Now try all lower case (i.e. first letter capitalized)
 445                 #
 446                 $title = Title::newFromText( strtolower( $this->rawText ) );
 447                 if ( 0 != $title->getArticleID() ) {
 448                         return $title;
 449                 }
 450
 451                 # Now try capitalized string
 452                 #
 453                 $title = Title::newFromText( ucwords( strtolower( $this->rawText ) ) );
 454                 if ( 0 != $title->getArticleID() ) {
 455                         return $title;
 456                 }
 457
 458                 # Now try all upper case
 459                 #
 460                 $title = Title::newFromText( strtoupper( $this->rawText ) );
 461                 if ( 0 != $title->getArticleID() ) {
 462                         return $title;
 463                 }
 464
 465                 # Entering an IP address goes to the contributions page
 466                 if ( preg_match( '/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/', $this->rawText ) ) {
 467                         $title = Title::makeTitle( NS_SPECIAL, "Contributions/" . $this->rawText );
 468                         return $title;
 469                 }
 470
 471                 return NULL;
 472         }
 473
 474         function goResult() {
 475                 global $wgOut, $wgGoToEdit;
 476                 global $wgDisableTextSearch;
 477                 $fname = 'SearchEngine::goResult';
 478
 479                 # Try to go to page as entered.
 480                 #
 481                 $t = Title::newFromText( $this->rawText );
 482
 483                 # If the string cannot be used to create a title
 484                 if( is_null( $t ) ){
 485                         $this->showResults();
 486                         return;
 487                 }
 488
 489                 # If there's an exact or very near match, jump right there.
 490                 $t = $this->getNearMatch();
 491                 if( !is_null( $t ) ) {
 492                         $wgOut->redirect( $t->getFullURL() );
 493                         return;
 494                 }
 495
 496                 # No match, generate an edit URL
 497                 $t = Title::newFromText( $this->rawText );
 498
 499                 # If the feature is enabled, go straight to the edit page
 500                 if ( $wgGoToEdit ) {
 501                         $wgOut->redirect( $t->getFullURL( 'action=edit' ) );
 502                         return;
 503                 }
 504
 505                 if( $t ) {
 506                         $editurl = $t->escapeLocalURL( 'action=edit' );
 507                 } else {
 508                         $editurl = ''; # ??
 509                 }
 510                 $wgOut->addHTML( '<p>' . wfMsg('nogomatch', $editurl, htmlspecialchars( $this->rawText ) ) . "</p>\n" );
 511
 512                 # Try a fuzzy title search
 513                 $anyhit = false;
 514                 global $wgDisableFuzzySearch;
 515                 if(! $wgDisableFuzzySearch ){
 516                         foreach( array(NS_MAIN, NS_PROJECT, NS_USER, NS_IMAGE, NS_MEDIAWIKI) as $namespace){
 517                                 $anyhit |= SearchEngine::doFuzzyTitleSearch( $this->rawText, $namespace );
 518                         }
 519                 }
 520
 521                 if( ! $anyhit ){
 522                         return $this->showResults();
 523                 }
 524         }
 525
 526         /**
 527          * @static
 528          */
 529         function doFuzzyTitleSearch( $search, $namespace ){
 530                 global $wgContLang, $wgOut;
 531
 532                 $this->setupPage();
 533
 534                 $sstr = ucfirst($search);
 535                 $sstr = str_replace(' ', '_', $sstr);
 536                 $fuzzymatches = SearchEngine::fuzzyTitles( $sstr, $namespace );
 537                 $fuzzymatches = array_slice($fuzzymatches, 0, 10);
 538                 $slen = strlen( $search );
 539                 $wikitext = '';
 540                 foreach($fuzzymatches as $res){
 541                         $t = str_replace('_', ' ', $res[1]);
 542                         $tfull = $wgContLang->getNsText( $namespace ) . ":$t|$t";
 543                         if( $namespace == NS_MAIN )
 544                                 $tfull = $t;
 545                         $distance = $res[0];
 546                         $closeness = (strlen( $search ) - $distance) / strlen( $search );
 547                         $percent = intval( $closeness * 100 ) . '%';
 548                         $stars = str_repeat('*', ceil(5 * $closeness) );
 549                         $wikitext .= "* [[$tfull]] $percent ($stars)\n";
 550                 }
 551                 if( $wikitext ){
 552                         if( $namespace != NS_MAIN )
 553                                 $wikitext = '=== ' . $wgContLang->getNsText( $namespace ) . " ===\n" . $wikitext;
 554                         $wgOut->addWikiText( $wikitext );
 555                         return true;
 556                 }
 557                 return false;
 558         }
 559
 560         /**
 561          * @static
 562          */
 563         function fuzzyTitles( $sstr, $namespace = NS_MAIN ){
 564                 $span = 0.10; // weed on title length before doing levenshtein.
 565                 $tolerance = 0.35; // allowed percentage of erronous characters
 566                 $slen = strlen($sstr);
 567                 $tolerance_count = ceil($tolerance * $slen);
 568                 $spanabs = ceil($slen * (1 + $span)) - $slen;
 569                 # print "Word: $sstr, len = $slen, range = [$min, $max], tolerance_count = $tolerance_count<BR>\n";
 570                 $result = array();
 571                 $cnt = 0;
 572                 for( $i=0; $i <= $spanabs; $i++ ){
 573                         $titles = SearchEngine::getTitlesByLength( $slen + $i, $namespace );
 574                         if( $i != 0) {
 575                                 $titles = array_merge($titles, SearchEngine::getTitlesByLength( $slen - $i, $namespace ) );
 576                         }
 577                         foreach($titles as $t){
 578                                 $d = levenshtein($sstr, $t);
 579                                 if($d < $tolerance_count)
 580                                         $result[] = array($d, $t);
 581                                 $cnt++;
 582                         }
 583                 }
 584                 usort($result, 'SearchEngine_pcmp');
 585                 return $result;
 586         }
 587
 588         /**
 589          * static
 590          */
 591         function getTitlesByLength($aLength, $aNamespace = 0){
 592                 global $wgMemc, $wgDBname;
 593                 $fname = 'SearchEngin::getTitlesByLength';
 594
 595                 // to avoid multiple costly SELECTs in case of no memcached
 596                 if( $this->allTitles ){
 597                         if( isset( $this->allTitles[$aLength][$aNamespace] ) ){
 598                                 return $this->allTitles[$aLength][$aNamespace];
 599                         } else {
 600                                 return array();
 601                         }
 602                 }
 603
 604                 $mkey = "$wgDBname:titlesbylength:$aLength:$aNamespace";
 605                 $mkeyts = "$wgDBname:titlesbylength:createtime";
 606                 $ts = $wgMemc->get( $mkeyts );
 607                 $result = $wgMemc->get( $mkey );
 608
 609                 if( time() - $ts < 3600 ){
 610                         // note: in case of insufficient memcached space, we return
 611                         // an empty list instead of starting to hit the DB.
 612                         return is_array( $result ) ? $result : array();
 613                 }
 614
 615                 $wgMemc->set( $mkeyts, time() );
 616
 617                 $res = $this->db->select( 'cur', array( 'cur_title', 'cur_namespace' ), false, $fname );
 618                 $titles = array(); // length, ns, [titles]
 619                 while( $obj = $this->db->fetchObject( $res ) ){
 620                         $title = $obj->cur_title;
 621                         $ns = $obj->cur_namespace;
 622                         $len = strlen( $title );
 623                         $titles[$len][$ns][] = $title;
 624                 }
 625                 foreach($titles as $length => $length_arr){
 626                         foreach($length_arr as $ns => $title_arr){
 627                                 $mkey = "$wgDBname:titlesbylength:$length:$ns";
 628                                 $wgMemc->set( $mkey, $title_arr, 3600 * 24 );
 629                         }
 630                 }
 631                 $this->allTitles = $titles;
 632                 if( isset( $titles[$aLength][$aNamespace] ) )
 633                         return $titles[$aLength][$aNamespace];
 634                 else
 635                         return array();
 636         }
 637 }
 638
 639 /**
 640  * @access private
 641  * @static
 642  */
 643 function SearchEngine_pcmp($a, $b){ return $a[0] - $b[0]; }
 644
 645 ?>