includes/SearchEngine.php

   1 <?php
   2 # See search.doc
   3
   4 class SearchEngine {
   5         /* private */ var $mRawtext, $mUsertext, $mSearchterms;
   6         /* private */ var $mTitlecond, $mTextcond;
   7
   8         var $doSearchRedirects = true;
   9         var $addtoquery = array();
  10         var $namespacesToSearch = array();
  11         var $alternateTitle;
  12         var $all_titles = false;
  13
  14         function SearchEngine( $text )
  15         {
  16                 # We display the query, so let's strip it for safety
  17                 #
  18                 global $wgDBmysql4;
  19                 $lc = SearchEngine::legalSearchChars() . "()";
  20                 if( $wgDBmysql4 ) $lc .= "\"~<>*+-";
  21                 $this->mRawtext = $text;
  22                 $this->mUsertext = trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  23                 $this->mSearchterms = array();
  24                 $this->mStrictMatching = true; # Google-style, add '+' on all terms
  25         }
  26
  27         function queryNamespaces()
  28         {
  29                 $namespaces = implode( ",", $this->namespacesToSearch );
  30                 if ($namespaces == "") {
  31                         $namespaces = "0";
  32                 }
  33                 return "AND cur_namespace IN (" . $namespaces . ")";
  34         }
  35
  36         function searchRedirects()
  37         {
  38                 if ( $this->doSearchRedirects ) {
  39                         return "";
  40                 } else {
  41                         return "AND cur_is_redirect=0 ";
  42                 }
  43         }
  44
  45         /* private */ function initNamespaceCheckbox( $i )
  46         {
  47                 global $wgUser, $wgNamespacesToBeSearchedDefault;
  48
  49                 if ($wgUser->getID()) {
  50                         // User is logged in so we retrieve his default namespaces
  51                         return $wgUser->getOption( "searchNs".$i );
  52                 } else {
  53                         // User is not logged in so we give him the global default namespaces
  54                         return !empty($wgNamespacesToBeSearchedDefault[ $i ]);
  55                 }
  56         }
  57
  58         # Display the "power search" footer. Does not actually perform the search,
  59         # that is done by showResults()
  60         function powersearch()
  61         {
  62                 global $wgUser, $wgOut, $wgLang, $wgTitle, $wgRequest;
  63                 $sk =& $wgUser->getSkin();
  64
  65                 $search                 = $wgRequest->getText( 'search' );
  66                 $searchx                = $wgRequest->getVal( 'searchx' );
  67                 $listredirs             = $wgRequest->getVal( 'redirs' );
  68
  69                 $ret = wfMsg("powersearchtext"); # Text to be returned
  70                 $tempText = ""; # Temporary text, for substitution into $ret
  71
  72                 if( isset( $_REQUEST["searchx"] ) ) {
  73                         $this->addtoquery["searchx"] = "1";
  74                 }
  75
  76                 # Do namespace checkboxes
  77                 $namespaces = $wgLang->getNamespaces();
  78                 foreach ( $namespaces as $i => $namespace ) {
  79                         # Skip virtual namespaces
  80                         if ( $i < 0 ) {
  81                                 continue;
  82                         }
  83
  84                         $formVar = "ns$i";
  85
  86                         # Initialise checkboxValues, either from defaults or from
  87                         # a previous invocation
  88                         if ( !isset( $searchx ) ) {
  89                                 $checkboxValue = $this->initNamespaceCheckbox( $i );
  90                         } else {
  91                                 $checkboxValue = $wgRequest->getVal( $formVar );
  92                         }
  93
  94                         $checked = "";
  95                         if ( $checkboxValue == 1 ) {
  96                                 $checked = " checked='checked'";
  97                                 $this->addtoquery["ns{$i}"] = 1;
  98                                 array_push( $this->namespacesToSearch, $i );
  99                         }
 100                         $name = str_replace( "_", " ", $namespaces[$i] );
 101                         if ( "" == $name ) {
 102                                 $name = wfMsg( "blanknamespace" );
 103                         }
 104
 105                         if ( $tempText !== "" ) {
 106                                 $tempText .= " ";
 107                         }
 108                         $tempText .= "<input type='checkbox' value=\"1\" name=\"" .
 109                           "ns{$i}\"{$checked} />{$name}\n";
 110                 }
 111                 $ret = str_replace ( "$1", $tempText, $ret );
 112
 113                 # List redirects checkbox
 114
 115                 $checked = "";
 116                 if ( $listredirs == 1 ) {
 117                         $this->addtoquery["redirs"] = 1;
 118                         $checked = " checked='checked'";
 119                 }
 120                 $tempText = "<input type='checkbox' value='1' name=\"redirs\"{$checked} />\n";
 121                 $ret = str_replace( "$2", $tempText, $ret );
 122
 123                 # Search field
 124
 125                 $tempText = "<input type='text' name=\"search\" value=\"" .
 126                         htmlspecialchars( $search ) ."\" width='80' />\n";
 127         $ret = str_replace( "$3", $tempText, $ret );
 128
 129                 # Searchx button
 130
 131                 $tempText = "<input type='submit' name=\"searchx\" value=\"" .
 132                   wfMsg("powersearch") . "\" />\n";
 133                 $ret = str_replace( "$9", $tempText, $ret );
 134
 135                 $action = $sk->escapeSearchLink();
 136                 $ret = "<br /><br />\n<form id=\"powersearch\" method=\"get\" " .
 137                   "action=\"$action\">\n{$ret}\n</form>\n";
 138
 139                 if ( isset ( $searchx ) ) {
 140                         if ( ! $listredirs ) {
 141                                 $this->doSearchRedirects = false;
 142                         }
 143                 }
 144                 return $ret;
 145         }
 146
 147         function setupPage() {
 148                 global $wgOut;
 149                 $wgOut->setPageTitle( wfMsg( "searchresults" ) );
 150                 $q = wfMsg( "searchquery", htmlspecialchars( $this->mRawtext ) );
 151                 $wgOut->setSubtitle( $q );
 152                 $wgOut->setArticleRelated( false );
 153                 $wgOut->setRobotpolicy( "noindex,nofollow" );
 154         }
 155
 156         # Perform the search and construct the results page
 157         function showResults()
 158         {
 159                 global $wgUser, $wgTitle, $wgOut, $wgLang, $wgRequest;
 160                 global $wgDisableTextSearch, $wgInputEncoding;
 161                 $fname = "SearchEngine::showResults";
 162
 163                 $search = $wgRequest->getText( 'search' );
 164
 165                 $powersearch = $this->powersearch(); /* Need side-effects here? */
 166
 167                 $this->setupPage();
 168
 169                 $sk = $wgUser->getSkin();
 170                 $header = wfMsg( "searchresulttext", $sk->makeKnownLink(
 171                                         wfMsg( "searchhelppage" ), wfMsg( "searchingwikipedia" ) ) );
 172                 $wgOut->addHTML( $header );
 173
 174                 $dbr =& wfGetDB( DB_SLAVE );
 175                 $this->parseQuery( $dbr );
 176                 if ( "" == $this->mTitlecond || "" == $this->mTextcond ) {
 177                         $wgOut->addHTML( "<h2>" . wfMsg( "badquery" ) . "</h2>\n" .
 178                           "<p>" . wfMsg( "badquerytext" ) . "</p>\n" );
 179                         return;
 180                 }
 181                 list( $limit, $offset ) = wfCheckLimits( 20, "searchlimit" );
 182
 183                 $searchnamespaces = $this->queryNamespaces();
 184                 $redircond = $this->searchRedirects();
 185                 $searchindex = $dbr->tableName( 'searchindex' );
 186                 $cur = $dbr->tableName( 'cur' );
 187
 188                 if ( $wgDisableTextSearch ) {
 189                         $wgOut->addHTML( wfMsg( "searchdisabled" ) );
 190                         $wgOut->addHTML( wfMsg( "googlesearch", htmlspecialchars( $search ), $GLOBALS['wgInputEncoding'] ) );
 191                 } else {
 192                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 193                           "cur_text FROM $cur,$searchindex " .
 194                           "WHERE cur_id=si_page AND {$this->mTitlecond} " .
 195                           "{$searchnamespaces} {$redircond}" .
 196                           "LIMIT {$offset}, {$limit}";
 197                         $res1 = $dbr->query( $sql, $fname );
 198                         $num = $dbr->numRows($res1);
 199
 200                         $sk = $wgUser->getSkin();
 201                         $text = "";
 202
 203                         $this->parseQuery( $dbr );
 204                         if ( "" == $this->mTitlecond || "" == $this->mTextcond ) {
 205                                 $wgOut->addHTML( "<h2>" . wfMsg( "badquery" ) . "</h2>\n" .
 206                                   "<p>" . wfMsg( "badquerytext" ) . "</p>\n" );
 207                                 return;
 208                         }
 209                         list( $limit, $offset ) = wfCheckLimits( 20, "searchlimit" );
 210
 211                         $searchnamespaces = $this->queryNamespaces();
 212                         $redircond = $this->searchRedirects();
 213
 214                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 215                           "cur_text FROM $cur,$searchindex " .
 216                           "WHERE cur_id=si_page AND {$this->mTitlecond} " .
 217                           "{$searchnamespaces} {$redircond}" .
 218                           "LIMIT {$offset}, {$limit}";
 219                         $res1 = $dbr->query( $sql, $fname );
 220                         $num = $dbr->numRows($res1);
 221
 222                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 223                           "cur_text FROM $cur,$searchindex " .
 224                           "WHERE cur_id=si_page AND {$this->mTextcond} " .
 225                           "{$searchnamespaces} {$redircond} " .
 226                           "LIMIT {$offset}, {$limit}";
 227                         $res2 = $dbr->query( $sql, $fname );
 228                         $num = $num + $dbr->numRows($res2);
 229
 230                         if ( $num == $limit ) {
 231                           $top = wfShowingResults( $offset, $limit);
 232                         } else {
 233                           $top = wfShowingResultsNum( $offset, $limit, $num );
 234                         }
 235                         $wgOut->addHTML( "<p>{$top}</p>\n" );
 236
 237                         # For powersearch
 238
 239                         $a2l = "" ;
 240                         $akk = array_keys( $this->addtoquery ) ;
 241                         foreach ( $akk AS $ak ) {
 242                                 $a2l .= "&{$ak}={$this->addtoquery[$ak]}" ;
 243                         }
 244
 245                         $sl = wfViewPrevNext( $offset, $limit, "",
 246                           "search=" . wfUrlencode( $this->mUsertext ) . $a2l );
 247                         $wgOut->addHTML( "<br />{$sl}\n" );
 248
 249                         $foundsome = false;
 250
 251                         if ( 0 == $dbr->numRows( $res1 ) ) {
 252                                 $wgOut->addHTML( "<h2>" . wfMsg( "notitlematches" ) .
 253                                   "</h2>\n" );
 254                         } else {
 255                                 $foundsome = true;
 256                                 $off = $offset + 1;
 257                                 $wgOut->addHTML( "<h2>" . wfMsg( "titlematches" ) .
 258                                   "</h2>\n<ol start='{$off}'>" );
 259
 260                                 while ( $row = $dbr->fetchObject( $res1 ) ) {
 261                                         $this->showHit( $row );
 262                                 }
 263                                 $dbr->freeResult( $res1 );
 264                                 $wgOut->addHTML( "</ol>\n" );
 265                         }
 266
 267                         if ( 0 == $dbr->numRows( $res2 ) ) {
 268                                 $wgOut->addHTML( "<h2>" . wfMsg( "notextmatches" ) .
 269                                   "</h2>\n" );
 270                         } else {
 271                                 $foundsome = true;
 272                                 $off = $offset + 1;
 273                                 $wgOut->addHTML( "<h2>" . wfMsg( "textmatches" ) . "</h2>\n" .
 274                                   "<ol start='{$off}'>" );
 275                                 while ( $row = $dbr->fetchObject( $res2 ) ) {
 276                                         $this->showHit( $row );
 277                                 }
 278                                 $dbr->freeResult( $res2 );
 279                                 $wgOut->addHTML( "</ol>\n" );
 280                         }
 281                         if ( ! $foundsome ) {
 282                                 $wgOut->addHTML( "<p>" . wfMsg( "nonefound" ) . "</p>\n" );
 283                         }
 284                         $wgOut->addHTML( "<p>{$sl}</p>\n" );
 285                         $wgOut->addHTML( $powersearch );
 286                 }
 287         }
 288
 289         function legalSearchChars()
 290         {
 291                 $lc = "A-Za-z_'0-9\\x80-\\xFF\\-";
 292                 return $lc;
 293         }
 294
 295         function parseQuery( &$db )
 296         {
 297                 global $wgDBminWordLen, $wgLang, $wgDBmysql4;
 298
 299                 if( $wgDBmysql4 ) {
 300                         # Use cleaner boolean search if available
 301                         return $this->parseQuery4( $db );
 302                 }
 303                 # on non mysql4 database: get list of words we don't want to search for
 304                 require_once( "FulltextStoplist.php" );
 305
 306                 $lc = SearchEngine::legalSearchChars() . "()";
 307                 $q = preg_replace( "/([()])/", " \\1 ", $this->mUsertext );
 308                 $q = preg_replace( "/\\s+/", " ", $q );
 309                 $w = explode( " ", trim( $q ) );
 310
 311                 $last = $cond = "";
 312                 foreach ( $w as $word ) {
 313                         $word = $wgLang->stripForSearch( $word );
 314                         if ( "and" == $word || "or" == $word || "not" == $word
 315                           || "(" == $word || ")" == $word ) {
 316                                 $cond .= " " . strtoupper( $word );
 317                                 $last = "";
 318                         } else if ( strlen( $word ) < $wgDBminWordLen ) {
 319                                 continue;
 320                         } else if ( FulltextStoplist::inList( $word ) ) {
 321                                 continue;
 322                         } else {
 323                                 if ( "" != $last ) { $cond .= " AND"; }
 324                                 $cond .= " (MATCH (##field##) AGAINST ('" .
 325                                   $db->strencode( $word ). "'))";
 326                                 $last = $word;
 327                                 array_push( $this->mSearchterms, "\\b" . $word . "\\b" );
 328                         }
 329                 }
 330                 if ( 0 == count( $this->mSearchterms ) ) { return; }
 331
 332                 $this->mTitlecond = "(" . str_replace( "##field##",
 333                   "si_title", $cond ) . " )";
 334
 335                 $this->mTextcond = "(" . str_replace( "##field##",
 336                   "si_text", $cond ) . " AND (cur_is_redirect=0) )";
 337         }
 338
 339         function parseQuery4( &$db )
 340         {
 341                 global $wgLang;
 342                 $lc = SearchEngine::legalSearchChars();
 343                 $searchon = "";
 344                 $this->mSearchterms = array();
 345
 346                 # FIXME: This doesn't handle parenthetical expressions.
 347                 if( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 348                           $this->mUsertext, $m, PREG_SET_ORDER ) ) {
 349                         foreach( $m as $terms ) {
 350                                 if( $searchon !== "" ) $searchon .= " ";
 351                                 if( $this->mStrictMatching && ($terms[1] == "") ) {
 352                                         $terms[1] = "+";
 353                                 }
 354                                 $searchon .= $terms[1] . $wgLang->stripForSearch( $terms[2] );
 355                                 if( $terms[3] ) {
 356                                         $regexp = preg_quote( $terms[3] );
 357                                         if( $terms[4] ) $regexp .= "[0-9A-Za-z_]+";
 358                                 } else {
 359                                         $regexp = preg_quote( str_replace( '"', '', $terms[2] ) );
 360                                 }
 361                                 $this->mSearchterms[] = $regexp;
 362                         }
 363                         wfDebug( "Would search with '$searchon'\n" );
 364                         wfDebug( "Match with /\b" . implode( '\b|\b', $this->mSearchterms ) . "\b/\n" );
 365                 } else {
 366                         wfDebug( "Can't understand search query '$this->mUsertext'\n" );
 367                 }
 368
 369                 $searchon = $db->strencode( $searchon );
 370                 $this->mTitlecond = " MATCH(si_title) AGAINST('$searchon' IN BOOLEAN MODE)";
 371                 $this->mTextcond = " (MATCH(si_text) AGAINST('$searchon' IN BOOLEAN MODE) AND cur_is_redirect=0)";
 372         }
 373
 374         function showHit( $row )
 375         {
 376                 global $wgUser, $wgOut, $wgLang;
 377
 378                 $t = Title::makeName( $row->cur_namespace, $row->cur_title );
 379                 $sk = $wgUser->getSkin();
 380
 381                 $contextlines = $wgUser->getOption( "contextlines" );
 382                 if ( "" == $contextlines ) { $contextlines = 5; }
 383                 $contextchars = $wgUser->getOption( "contextchars" );
 384                 if ( "" == $contextchars ) { $contextchars = 50; }
 385
 386                 $link = $sk->makeKnownLink( $t, "" );
 387                 $size = wfMsg( "nbytes", strlen( $row->cur_text ) );
 388                 $wgOut->addHTML( "<li>{$link} ({$size})" );
 389
 390                 $lines = explode( "\n", $row->cur_text );
 391                 $pat1 = "/(.*)(" . implode( "|", $this->mSearchterms ) . ")(.*)/i";
 392                 $lineno = 0;
 393
 394                 foreach ( $lines as $line ) {
 395                         if ( 0 == $contextlines ) {
 396                                 break;
 397                         }
 398                         --$contextlines;
 399                         ++$lineno;
 400                         if ( ! preg_match( $pat1, $line, $m ) ) {
 401                                 continue;
 402                         }
 403
 404                         $pre = $wgLang->truncate( $m[1], -$contextchars, "..." );
 405
 406                         if ( count( $m ) < 3 ) {
 407                                 $post = "";
 408                         } else {
 409                                 $post = $wgLang->truncate( $m[3], $contextchars, "..." );
 410                         }
 411
 412                         $found = $m[2];
 413
 414                         $line = htmlspecialchars( $pre . $found . $post );
 415                         $pat2 = "/(" . implode( "|", $this->mSearchterms ) . ")/i";
 416                         $line = preg_replace( $pat2,
 417                           "<font color='red'>\\1</font>", $line );
 418
 419                         $wgOut->addHTML( "<br /><small>{$lineno}: {$line}</small>\n" );
 420                 }
 421                 $wgOut->addHTML( "</li>\n" );
 422         }
 423
 424         function goResult()
 425         {
 426                 global $wgOut, $wgRequest, $wgGoToEdit;
 427                 global $wgDisableTextSearch;
 428                 $fname = "SearchEngine::goResult";
 429
 430                 $search = trim( $wgRequest->getText( "search" ) );
 431
 432                 # Try to go to page as entered.
 433                 #
 434                 $t = Title::newFromText( $search );
 435
 436                 # If the string cannot be used to create a title
 437                 if( false == $t ){
 438                         $this->showResults();
 439                         return;
 440                 }
 441
 442                 # Exact match? No need to look further.
 443                 if ( $t->getNamespace() == NS_SPECIAL || 0 != $t->getArticleID() ) {
 444                         $wgOut->redirect( $t->getFullURL() );
 445                         return;
 446                 }
 447
 448                 # Now try all lower case (i.e. first letter capitalized)
 449                 #
 450                 $t = Title::newFromText( strtolower( $search ) );
 451                 if ( 0 != $t->getArticleID() ) {
 452                         $wgOut->redirect( $t->getFullURL() );
 453                         return;
 454                 }
 455
 456                 # Now try capitalized string
 457                 #
 458                 $t = Title::newFromText( ucwords( strtolower( $search ) ) );
 459                 if ( 0 != $t->getArticleID() ) {
 460                         $wgOut->redirect( $t->getFullURL() );
 461                         return;
 462                 }
 463
 464                 # Now try all upper case
 465                 #
 466                 $t = Title::newFromText( strtoupper( $search ) );
 467                 if ( 0 != $t->getArticleID() ) {
 468                         $wgOut->redirect( $t->getFullURL() );
 469                         return;
 470                 }
 471
 472                 # Entering an IP address goes to the contributions page
 473                 if ( preg_match( '/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/', $search ) ) {
 474                         $title = Title::makeTitle( NS_SPECIAL, "Contributions" );
 475                         $wgOut->redirect( $title->getFullUrl( "target=$search" ) );
 476                         return;
 477                 }
 478
 479                 # No match, generate an edit URL
 480                 $t = Title::newFromText( $this->mRawtext );
 481
 482                 # If the feature is enabled, go straight to the edit page
 483                 if ( $wgGoToEdit ) {
 484                         $wgOut->redirect( $t->getFullURL( "action=edit" ) );
 485                         return;
 486                 }
 487
 488                 if( $t ) {
 489                         $editurl = $t->escapeLocalURL( "action=edit" );
 490                 } else {
 491                         $editurl = ""; # ??
 492                 }
 493                 $wgOut->addHTML( "<p>" . wfMsg("nogomatch", $editurl ) . "</p>\n" );
 494
 495                 # Try a fuzzy title search
 496                 $anyhit = false;
 497                 global $wgDisableFuzzySearch;
 498                 if(! $wgDisableFuzzySearch ){
 499                         foreach( array(NS_MAIN, NS_WP, NS_USER, NS_IMAGE, NS_MEDIAWIKI) as $namespace){
 500                                 $anyhit |= SearchEngine::doFuzzyTitleSearch( $search, $namespace );
 501                         }
 502                 }
 503
 504                 if( ! $anyhit ){
 505                         return $this->showResults();
 506                 }
 507         }
 508
 509         /* static */ function doFuzzyTitleSearch( $search, $namespace ){
 510                 global $wgLang, $wgOut;
 511
 512                 $this->setupPage();
 513
 514                 $sstr = ucfirst($search);
 515                 $sstr = str_replace(" ", "_", $sstr);
 516                 $fuzzymatches = SearchEngine::fuzzyTitles( $sstr, $namespace );
 517                 $fuzzymatches = array_slice($fuzzymatches, 0, 10);
 518                 $slen = strlen( $search );
 519                 $wikitext = "";
 520                 foreach($fuzzymatches as $res){
 521                         $t = str_replace("_", " ", $res[1]);
 522                         $tfull = $wgLang->getNsText( $namespace ) . ":$t|$t";
 523                         if( $namespace == NS_MAIN )
 524                                 $tfull = "$t";
 525                         $distance = $res[0];
 526                         $closeness = (strlen( $search ) - $distance) / strlen( $search );
 527                         $percent = intval( $closeness * 100 ) . "%";
 528                         $stars = str_repeat("*", ceil(5 * $closeness) );
 529                         $wikitext .= "* [[$tfull]] $percent ($stars)\n";
 530                 }
 531                 if( $wikitext ){
 532                         if( $namespace != NS_MAIN )
 533                                 $wikitext = "=== " . $wgLang->getNsText( $namespace ) . " ===\n" . $wikitext;
 534                         $wgOut->addWikiText( $wikitext );
 535                         return true;
 536                 }
 537                 return false;
 538         }
 539
 540         /* static */ function fuzzyTitles( $sstr, $namespace = NS_MAIN ){
 541                 $span = 0.10; // weed on title length before doing levenshtein.
 542                 $tolerance = 0.35; // allowed percentage of erronous characters
 543                 $slen = strlen($sstr);
 544                 $tolerance_count = ceil($tolerance * $slen);
 545                 $spanabs = ceil($slen * (1 + $span)) - $slen;
 546                 # print "Word: $sstr, len = $slen, range = [$min, $max], tolerance_count = $tolerance_count<BR>\n";
 547                 $result = array();
 548                 $cnt = 0;
 549                 for( $i=0; $i <= $spanabs; $i++ ){
 550                         $titles = SearchEngine::getTitlesByLength( $slen + $i, $namespace );
 551                         if( $i != 0) {
 552                                 $titles = array_merge($titles, SearchEngine::getTitlesByLength( $slen - $i, $namespace ) );
 553                         }
 554                         foreach($titles as $t){
 555                                 $d = levenshtein($sstr, $t);
 556                                 if($d < $tolerance_count)
 557                                         $result[] = array($d, $t);
 558                                 $cnt++;
 559                         }
 560                 }
 561                 usort($result, "SearchEngine_pcmp");
 562                 return $result;
 563         }
 564
 565         /* static */ function getTitlesByLength($aLength, $aNamespace = 0){
 566                 global $wgMemc, $wgDBname;
 567                 $fname = 'SearchEngin::getTitlesByLength';
 568
 569                 // to avoid multiple costly SELECTs in case of no memcached
 570                 if( $this->all_titles ){
 571                         if( isset( $this->all_titles[$aLength][$aNamespace] ) ){
 572                                 return $this->all_titles[$aLength][$aNamespace];
 573                         } else {
 574                                 return array();
 575                         }
 576                 }
 577
 578                 $mkey = "$wgDBname:titlesbylength:$aLength:$aNamespace";
 579                 $mkeyts = "$wgDBname:titlesbylength:createtime";
 580                 $ts = $wgMemc->get( $mkeyts );
 581                 $result = $wgMemc->get( $mkey );
 582
 583                 if( time() - $ts < 3600 ){
 584                         // note: in case of insufficient memcached space, we return
 585                         // an empty list instead of starting to hit the DB.
 586                         return is_array( $result ) ? $result : array();
 587                 }
 588
 589                 $wgMemc->set( $mkeyts, time() );
 590
 591                 $dbr =& wfGetDB( DB_SLAVE );
 592                 $res = $dbr->select( 'cur', array( 'cur_title', 'cur_namespace' ), false, $fname );
 593                 $titles = array(); // length, ns, [titles]
 594                 while( $obj = $dbr->fetchObject( $res ) ){
 595                         $title = $obj->cur_title;
 596                         $ns = $obj->cur_namespace;
 597                         $len = strlen( $title );
 598                         $titles[$len][$ns][] = $title;
 599                 }
 600                 foreach($titles as $length => $length_arr){
 601                         foreach($length_arr as $ns => $title_arr){
 602                                 $mkey = "$wgDBname:titlesbylength:$length:$ns";
 603                                 $wgMemc->set( $mkey, $title_arr, 3600 * 24 );
 604                         }
 605                 }
 606                 $this->all_titles = $titles;
 607                 if( isset( $titles[$aLength][$aNamespace] ) )
 608                         return $titles[$aLength][$aNamespace];
 609                 else
 610                         return array();
 611         }
 612 }
 613
 614 /* private static */ function SearchEngine_pcmp($a, $b){ return $a[0] - $b[0]; }
 615
 616 ?>