includes/CategoryViewer.php

   1 <?php
   2 /**
   3  * List and paging of category members.
   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  */
  22
  23 class CategoryViewer extends ContextSource {
  24         /** @var int */
  25         public $limit;
  26
  27         /** @var array */
  28         protected $from;
  29
  30         /** @var array */
  31         protected $until;
  32
  33         /** @var string[] */
  34         public $articles;
  35
  36         /** @var array */
  37         public $articles_start_char;
  38
  39         /** @var array */
  40         protected $children;
  41
  42         /** @var array */
  43         protected $children_start_char;
  44
  45         /** @var bool */
  46         protected $showGallery;
  47
  48         /** @var array */
  49         protected $imgsNoGallery_start_char;
  50
  51         /** @var array */
  52         protected $imgsNoGallery;
  53
  54         /** @var array */
  55         protected $nextPage;
  56
  57         /** @var array */
  58         protected $prevPage;
  59
  60         /** @var array */
  61         protected $flip;
  62
  63         /** @var Title */
  64         protected $title;
  65
  66         /** @var Collation */
  67         protected $collation;
  68
  69         /** @var ImageGallery */
  70         protected $gallery;
  71
  72         /** @var Category Category object for this page. */
  73         private $cat;
  74
  75         /** @var array The original query array, to be used in generating paging links. */
  76         private $query;
  77
  78         /**
  79          * @since 1.19 $context is a second, required parameter
  80          * @param Title $title
  81          * @param IContextSource $context
  82          * @param array $from An array with keys page, subcat,
  83          *        and file for offset of results of each section (since 1.17)
  84          * @param array $until An array with 3 keys for until of each section (since 1.17)
  85          * @param array $query
  86          */
  87         function __construct( $title, IContextSource $context, $from = array(),
  88                 $until = array(), $query = array()
  89         ) {
  90                 global $wgCategoryPagingLimit;
  91                 $this->title = $title;
  92                 $this->setContext( $context );
  93                 $this->from = $from;
  94                 $this->until = $until;
  95                 $this->limit = $wgCategoryPagingLimit;
  96                 $this->cat = Category::newFromTitle( $title );
  97                 $this->query = $query;
  98                 $this->collation = Collation::singleton();
  99                 unset( $this->query['title'] );
 100         }
 101
 102         /**
 103          * Format the category data list.
 104          *
 105          * @return string HTML output
 106          */
 107         public function getHTML() {
 108                 global $wgCategoryMagicGallery;
 109                 wfProfileIn( __METHOD__ );
 110
 111                 $this->showGallery = $wgCategoryMagicGallery && !$this->getOutput()->mNoGallery;
 112
 113                 $this->clearCategoryState();
 114                 $this->doCategoryQuery();
 115                 $this->finaliseCategoryState();
 116
 117                 $r = $this->getSubcategorySection() .
 118                         $this->getPagesSection() .
 119                         $this->getImageSection();
 120
 121                 if ( $r == '' ) {
 122                         // If there is no category content to display, only
 123                         // show the top part of the navigation links.
 124                         // @todo FIXME: Cannot be completely suppressed because it
 125                         //        is unknown if 'until' or 'from' makes this
 126                         //        give 0 results.
 127                         $r = $r . $this->getCategoryTop();
 128                 } else {
 129                         $r = $this->getCategoryTop() .
 130                                 $r .
 131                                 $this->getCategoryBottom();
 132                 }
 133
 134                 // Give a proper message if category is empty
 135                 if ( $r == '' ) {
 136                         $r = $this->msg( 'category-empty' )->parseAsBlock();
 137                 }
 138
 139                 $lang = $this->getLanguage();
 140                 $langAttribs = array( 'lang' => $lang->getCode(), 'dir' => $lang->getDir() );
 141                 # put a div around the headings which are in the user language
 142                 $r = Html::openElement( 'div', $langAttribs ) . $r . '</div>';
 143
 144                 wfProfileOut( __METHOD__ );
 145                 return $r;
 146         }
 147
 148         function clearCategoryState() {
 149                 $this->articles = array();
 150                 $this->articles_start_char = array();
 151                 $this->children = array();
 152                 $this->children_start_char = array();
 153                 if ( $this->showGallery ) {
 154                         // Note that null for mode is taken to mean use default.
 155                         $mode = $this->getRequest()->getVal( 'gallerymode', null );
 156                         try {
 157                                 $this->gallery = ImageGalleryBase::factory( $mode, $this->getContext() );
 158                         } catch ( MWException $e ) {
 159                                 // User specified something invalid, fallback to default.
 160                                 $this->gallery = ImageGalleryBase::factory( false, $this->getContext() );
 161                         }
 162
 163                         $this->gallery->setHideBadImages();
 164                 } else {
 165                         $this->imgsNoGallery = array();
 166                         $this->imgsNoGallery_start_char = array();
 167                 }
 168         }
 169
 170         /**
 171          * Add a subcategory to the internal lists, using a Category object
 172          * @param Category $cat
 173          * @param string $sortkey
 174          * @param int $pageLength
 175          */
 176         function addSubcategoryObject( Category $cat, $sortkey, $pageLength ) {
 177                 // Subcategory; strip the 'Category' namespace from the link text.
 178                 $title = $cat->getTitle();
 179
 180                 $link = Linker::link( $title, htmlspecialchars( $title->getText() ) );
 181                 if ( $title->isRedirect() ) {
 182                         // This didn't used to add redirect-in-category, but might
 183                         // as well be consistent with the rest of the sections
 184                         // on a category page.
 185                         $link = '<span class="redirect-in-category">' . $link . '</span>';
 186                 }
 187                 $this->children[] = $link;
 188
 189                 $this->children_start_char[] =
 190                         $this->getSubcategorySortChar( $cat->getTitle(), $sortkey );
 191         }
 192
 193         /**
 194          * Get the character to be used for sorting subcategories.
 195          * If there's a link from Category:A to Category:B, the sortkey of the resulting
 196          * entry in the categorylinks table is Category:A, not A, which it SHOULD be.
 197          * Workaround: If sortkey == "Category:".$title, than use $title for sorting,
 198          * else use sortkey...
 199          *
 200          * @param Title $title
 201          * @param string $sortkey The human-readable sortkey (before transforming to icu or whatever).
 202          * @return string
 203          */
 204         function getSubcategorySortChar( $title, $sortkey ) {
 205                 global $wgContLang;
 206
 207                 if ( $title->getPrefixedText() == $sortkey ) {
 208                         $word = $title->getDBkey();
 209                 } else {
 210                         $word = $sortkey;
 211                 }
 212
 213                 $firstChar = $this->collation->getFirstLetter( $word );
 214
 215                 return $wgContLang->convert( $firstChar );
 216         }
 217
 218         /**
 219          * Add a page in the image namespace
 220          * @param Title $title
 221          * @param string $sortkey
 222          * @param int $pageLength
 223          * @param bool $isRedirect
 224          */
 225         function addImage( Title $title, $sortkey, $pageLength, $isRedirect = false ) {
 226                 global $wgContLang;
 227                 if ( $this->showGallery ) {
 228                         $flip = $this->flip['file'];
 229                         if ( $flip ) {
 230                                 $this->gallery->insert( $title );
 231                         } else {
 232                                 $this->gallery->add( $title );
 233                         }
 234                 } else {
 235                         $link = Linker::link( $title );
 236                         if ( $isRedirect ) {
 237                                 // This seems kind of pointless given 'mw-redirect' class,
 238                                 // but keeping for back-compatibility with user css.
 239                                 $link = '<span class="redirect-in-category">' . $link . '</span>';
 240                         }
 241                         $this->imgsNoGallery[] = $link;
 242
 243                         $this->imgsNoGallery_start_char[] = $wgContLang->convert(
 244                                 $this->collation->getFirstLetter( $sortkey ) );
 245                 }
 246         }
 247
 248         /**
 249          * Add a miscellaneous page
 250          * @param Title $title
 251          * @param string $sortkey
 252          * @param int $pageLength
 253          * @param bool $isRedirect
 254          */
 255         function addPage( $title, $sortkey, $pageLength, $isRedirect = false ) {
 256                 global $wgContLang;
 257
 258                 $link = Linker::link( $title );
 259                 if ( $isRedirect ) {
 260                         // This seems kind of pointless given 'mw-redirect' class,
 261                         // but keeping for back-compatibility with user css.
 262                         $link = '<span class="redirect-in-category">' . $link . '</span>';
 263                 }
 264                 $this->articles[] = $link;
 265
 266                 $this->articles_start_char[] = $wgContLang->convert(
 267                         $this->collation->getFirstLetter( $sortkey ) );
 268         }
 269
 270         function finaliseCategoryState() {
 271                 if ( $this->flip['subcat'] ) {
 272                         $this->children = array_reverse( $this->children );
 273                         $this->children_start_char = array_reverse( $this->children_start_char );
 274                 }
 275                 if ( $this->flip['page'] ) {
 276                         $this->articles = array_reverse( $this->articles );
 277                         $this->articles_start_char = array_reverse( $this->articles_start_char );
 278                 }
 279                 if ( !$this->showGallery && $this->flip['file'] ) {
 280                         $this->imgsNoGallery = array_reverse( $this->imgsNoGallery );
 281                         $this->imgsNoGallery_start_char = array_reverse( $this->imgsNoGallery_start_char );
 282                 }
 283         }
 284
 285         function doCategoryQuery() {
 286                 $dbr = wfGetDB( DB_SLAVE, 'category' );
 287
 288                 $this->nextPage = array(
 289                         'page' => null,
 290                         'subcat' => null,
 291                         'file' => null,
 292                 );
 293                 $this->prevPage = array(
 294                         'page' => null,
 295                         'subcat' => null,
 296                         'file' => null,
 297                 );
 298
 299                 $this->flip = array( 'page' => false, 'subcat' => false, 'file' => false );
 300
 301                 foreach ( array( 'page', 'subcat', 'file' ) as $type ) {
 302                         # Get the sortkeys for start/end, if applicable.  Note that if
 303                         # the collation in the database differs from the one
 304                         # set in $wgCategoryCollation, pagination might go totally haywire.
 305                         $extraConds = array( 'cl_type' => $type );
 306                         if ( isset( $this->from[$type] ) && $this->from[$type] !== null ) {
 307                                 $extraConds[] = 'cl_sortkey >= '
 308                                         . $dbr->addQuotes( $this->collation->getSortKey( $this->from[$type] ) );
 309                         } elseif ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
 310                                 $extraConds[] = 'cl_sortkey < '
 311                                         . $dbr->addQuotes( $this->collation->getSortKey( $this->until[$type] ) );
 312                                 $this->flip[$type] = true;
 313                         }
 314
 315                         $res = $dbr->select(
 316                                 array( 'page', 'categorylinks', 'category' ),
 317                                 array( 'page_id', 'page_title', 'page_namespace', 'page_len',
 318                                         'page_is_redirect', 'cl_sortkey', 'cat_id', 'cat_title',
 319                                         'cat_subcats', 'cat_pages', 'cat_files',
 320                                         'cl_sortkey_prefix', 'cl_collation' ),
 321                                 array_merge( array( 'cl_to' => $this->title->getDBkey() ), $extraConds ),
 322                                 __METHOD__,
 323                                 array(
 324                                         'USE INDEX' => array( 'categorylinks' => 'cl_sortkey' ),
 325                                         'LIMIT' => $this->limit + 1,
 326                                         'ORDER BY' => $this->flip[$type] ? 'cl_sortkey DESC' : 'cl_sortkey',
 327                                 ),
 328                                 array(
 329                                         'categorylinks' => array( 'INNER JOIN', 'cl_from = page_id' ),
 330                                         'category' => array( 'LEFT JOIN', array(
 331                                                 'cat_title = page_title',
 332                                                 'page_namespace' => NS_CATEGORY
 333                                         ))
 334                                 )
 335                         );
 336
 337                         $count = 0;
 338                         foreach ( $res as $row ) {
 339                                 $title = Title::newFromRow( $row );
 340                                 if ( $row->cl_collation === '' ) {
 341                                         // Hack to make sure that while updating from 1.16 schema
 342                                         // and db is inconsistent, that the sky doesn't fall.
 343                                         // See r83544. Could perhaps be removed in a couple decades...
 344                                         $humanSortkey = $row->cl_sortkey;
 345                                 } else {
 346                                         $humanSortkey = $title->getCategorySortkey( $row->cl_sortkey_prefix );
 347                                 }
 348
 349                                 if ( ++$count > $this->limit ) {
 350                                         # We've reached the one extra which shows that there
 351                                         # are additional pages to be had. Stop here...
 352                                         $this->nextPage[$type] = $humanSortkey;
 353                                         break;
 354                                 }
 355                                 if ( $count == $this->limit ) {
 356                                         $this->prevPage[$type] = $humanSortkey;
 357                                 }
 358
 359                                 if ( $title->getNamespace() == NS_CATEGORY ) {
 360                                         $cat = Category::newFromRow( $row, $title );
 361                                         $this->addSubcategoryObject( $cat, $humanSortkey, $row->page_len );
 362                                 } elseif ( $title->getNamespace() == NS_FILE ) {
 363                                         $this->addImage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
 364                                 } else {
 365                                         $this->addPage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
 366                                 }
 367                         }
 368                 }
 369         }
 370
 371         /**
 372          * @return string
 373          */
 374         function getCategoryTop() {
 375                 $r = $this->getCategoryBottom();
 376                 return $r === ''
 377                         ? $r
 378                         : "<br style=\"clear:both;\"/>\n" . $r;
 379         }
 380
 381         /**
 382          * @return string
 383          */
 384         function getSubcategorySection() {
 385                 # Don't show subcategories section if there are none.
 386                 $r = '';
 387                 $rescnt = count( $this->children );
 388                 $dbcnt = $this->cat->getSubcatCount();
 389                 $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'subcat' );
 390
 391                 if ( $rescnt > 0 ) {
 392                         # Showing subcategories
 393                         $r .= "<div id=\"mw-subcategories\">\n";
 394                         $r .= '<h2>' . $this->msg( 'subcategories' )->text() . "</h2>\n";
 395                         $r .= $countmsg;
 396                         $r .= $this->getSectionPagingLinks( 'subcat' );
 397                         $r .= $this->formatList( $this->children, $this->children_start_char );
 398                         $r .= $this->getSectionPagingLinks( 'subcat' );
 399                         $r .= "\n</div>";
 400                 }
 401                 return $r;
 402         }
 403
 404         /**
 405          * @return string
 406          */
 407         function getPagesSection() {
 408                 $ti = wfEscapeWikiText( $this->title->getText() );
 409                 # Don't show articles section if there are none.
 410                 $r = '';
 411
 412                 # @todo FIXME: Here and in the other two sections: we don't need to bother
 413                 # with this rigmarole if the entire category contents fit on one page
 414                 # and have already been retrieved.  We can just use $rescnt in that
 415                 # case and save a query and some logic.
 416                 $dbcnt = $this->cat->getPageCount() - $this->cat->getSubcatCount()
 417                         - $this->cat->getFileCount();
 418                 $rescnt = count( $this->articles );
 419                 $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'article' );
 420
 421                 if ( $rescnt > 0 ) {
 422                         $r = "<div id=\"mw-pages\">\n";
 423                         $r .= '<h2>' . $this->msg( 'category_header', $ti )->text() . "</h2>\n";
 424                         $r .= $countmsg;
 425                         $r .= $this->getSectionPagingLinks( 'page' );
 426                         $r .= $this->formatList( $this->articles, $this->articles_start_char );
 427                         $r .= $this->getSectionPagingLinks( 'page' );
 428                         $r .= "\n</div>";
 429                 }
 430                 return $r;
 431         }
 432
 433         /**
 434          * @return string
 435          */
 436         function getImageSection() {
 437                 $r = '';
 438                 $rescnt = $this->showGallery ? $this->gallery->count() : count( $this->imgsNoGallery );
 439                 if ( $rescnt > 0 ) {
 440                         $dbcnt = $this->cat->getFileCount();
 441                         $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'file' );
 442
 443                         $r .= "<div id=\"mw-category-media\">\n";
 444                         $r .= '<h2>' .
 445                                 $this->msg(
 446                                         'category-media-header',
 447                                         wfEscapeWikiText( $this->title->getText() )
 448                                 )->text() .
 449                                 "</h2>\n";
 450                         $r .= $countmsg;
 451                         $r .= $this->getSectionPagingLinks( 'file' );
 452                         if ( $this->showGallery ) {
 453                                 $r .= $this->gallery->toHTML();
 454                         } else {
 455                                 $r .= $this->formatList( $this->imgsNoGallery, $this->imgsNoGallery_start_char );
 456                         }
 457                         $r .= $this->getSectionPagingLinks( 'file' );
 458                         $r .= "\n</div>";
 459                 }
 460                 return $r;
 461         }
 462
 463         /**
 464          * Get the paging links for a section (subcats/pages/files), to go at the top and bottom
 465          * of the output.
 466          *
 467          * @param string $type 'page', 'subcat', or 'file'
 468          * @return string HTML output, possibly empty if there are no other pages
 469          */
 470         private function getSectionPagingLinks( $type ) {
 471                 if ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
 472                         // The new value for the until parameter should be pointing to the first
 473                         // result displayed on the page which is the second last result retrieved
 474                         // from the database.The next link should have a from parameter pointing
 475                         // to the until parameter of the current page.
 476                         if ( $this->nextPage[$type] !== null ) {
 477                                 return $this->pagingLinks( $this->prevPage[$type], $this->until[$type], $type );
 478                         } else {
 479                                 // If the nextPage variable is null, it means that we have reached the first page
 480                                 // and therefore the previous link should be disabled.
 481                                 return $this->pagingLinks( null, $this->until[$type], $type );
 482                         }
 483                 } elseif ( $this->nextPage[$type] !== null
 484                         || ( isset( $this->from[$type] ) && $this->from[$type] !== null )
 485                 ) {
 486                         return $this->pagingLinks( $this->from[$type], $this->nextPage[$type], $type );
 487                 } else {
 488                         return '';
 489                 }
 490         }
 491
 492         /**
 493          * @return string
 494          */
 495         function getCategoryBottom() {
 496                 return '';
 497         }
 498
 499         /**
 500          * Format a list of articles chunked by letter, either as a
 501          * bullet list or a columnar format, depending on the length.
 502          *
 503          * @param array $articles
 504          * @param array $articles_start_char
 505          * @param int $cutoff
 506          * @return string
 507          * @private
 508          */
 509         function formatList( $articles, $articles_start_char, $cutoff = 6 ) {
 510                 $list = '';
 511                 if ( count( $articles ) > $cutoff ) {
 512                         $list = self::columnList( $articles, $articles_start_char );
 513                 } elseif ( count( $articles ) > 0 ) {
 514                         // for short lists of articles in categories.
 515                         $list = self::shortList( $articles, $articles_start_char );
 516                 }
 517
 518                 $pageLang = $this->title->getPageLanguage();
 519                 $attribs = array( 'lang' => $pageLang->getCode(), 'dir' => $pageLang->getDir(),
 520                         'class' => 'mw-content-' . $pageLang->getDir() );
 521                 $list = Html::rawElement( 'div', $attribs, $list );
 522
 523                 return $list;
 524         }
 525
 526         /**
 527          * Format a list of articles chunked by letter in a three-column
 528          * list, ordered vertically.
 529          *
 530          * TODO: Take the headers into account when creating columns, so they're
 531          * more visually equal.
 532          *
 533          * More distant TODO: Scrap this and use CSS columns, whenever IE finally
 534          * supports those.
 535          *
 536          * @param array $articles
 537          * @param string[] $articles_start_char
 538          * @return string
 539          * @private
 540          */
 541         static function columnList( $articles, $articles_start_char ) {
 542                 $columns = array_combine( $articles, $articles_start_char );
 543                 # Split into three columns
 544                 $columns = array_chunk( $columns, ceil( count( $columns ) / 3 ), true /* preserve keys */ );
 545
 546                 $ret = '<table style="width: 100%;"><tr style="vertical-align: top;">';
 547                 $prevchar = null;
 548
 549                 foreach ( $columns as $column ) {
 550                         $ret .= '<td style="width: 33.3%;">';
 551                         $colContents = array();
 552
 553                         # Kind of like array_flip() here, but we keep duplicates in an
 554                         # array instead of dropping them.
 555                         foreach ( $column as $article => $char ) {
 556                                 if ( !isset( $colContents[$char] ) ) {
 557                                         $colContents[$char] = array();
 558                                 }
 559                                 $colContents[$char][] = $article;
 560                         }
 561
 562                         $first = true;
 563                         foreach ( $colContents as $char => $articles ) {
 564                                 # Change space to non-breaking space to keep headers aligned
 565                                 $h3char = $char === ' ' ? '&#160;' : htmlspecialchars( $char );
 566
 567                                 $ret .= '<h3>' . $h3char;
 568                                 if ( $first && $char === $prevchar ) {
 569                                         # We're continuing a previous chunk at the top of a new
 570                                         # column, so add " cont." after the letter.
 571                                         $ret .= ' ' . wfMessage( 'listingcontinuesabbrev' )->escaped();
 572                                 }
 573                                 $ret .= "</h3>\n";
 574
 575                                 $ret .= '<ul><li>';
 576                                 $ret .= implode( "</li>\n<li>", $articles );
 577                                 $ret .= '</li></ul>';
 578
 579                                 $first = false;
 580                                 $prevchar = $char;
 581                         }
 582
 583                         $ret .= "</td>\n";
 584                 }
 585
 586                 $ret .= '</tr></table>';
 587                 return $ret;
 588         }
 589
 590         /**
 591          * Format a list of articles chunked by letter in a bullet list.
 592          * @param array $articles
 593          * @param string[] $articles_start_char
 594          * @return string
 595          * @private
 596          */
 597         static function shortList( $articles, $articles_start_char ) {
 598                 $r = '<h3>' . htmlspecialchars( $articles_start_char[0] ) . "</h3>\n";
 599                 $r .= '<ul><li>' . $articles[0] . '</li>';
 600                 $articleCount = count( $articles );
 601                 for ( $index = 1; $index < $articleCount; $index++ ) {
 602                         if ( $articles_start_char[$index] != $articles_start_char[$index - 1] ) {
 603                                 $r .= "</ul><h3>" . htmlspecialchars( $articles_start_char[$index] ) . "</h3>\n<ul>";
 604                         }
 605
 606                         $r .= "<li>{$articles[$index]}</li>";
 607                 }
 608                 $r .= '</ul>';
 609                 return $r;
 610         }
 611
 612         /**
 613          * Create paging links, as a helper method to getSectionPagingLinks().
 614          *
 615          * @param string $first The 'until' parameter for the generated URL
 616          * @param string $last The 'from' parameter for the generated URL
 617          * @param string $type A prefix for parameters, 'page' or 'subcat' or
 618          *     'file'
 619          * @return string HTML
 620          */
 621         private function pagingLinks( $first, $last, $type = '' ) {
 622                 $prevLink = $this->msg( 'prevn' )->numParams( $this->limit )->escaped();
 623
 624                 if ( $first != '' ) {
 625                         $prevQuery = $this->query;
 626                         $prevQuery["{$type}until"] = $first;
 627                         unset( $prevQuery["{$type}from"] );
 628                         $prevLink = Linker::linkKnown(
 629                                 $this->addFragmentToTitle( $this->title, $type ),
 630                                 $prevLink,
 631                                 array(),
 632                                 $prevQuery
 633                         );
 634                 }
 635
 636                 $nextLink = $this->msg( 'nextn' )->numParams( $this->limit )->escaped();
 637
 638                 if ( $last != '' ) {
 639                         $lastQuery = $this->query;
 640                         $lastQuery["{$type}from"] = $last;
 641                         unset( $lastQuery["{$type}until"] );
 642                         $nextLink = Linker::linkKnown(
 643                                 $this->addFragmentToTitle( $this->title, $type ),
 644                                 $nextLink,
 645                                 array(),
 646                                 $lastQuery
 647                         );
 648                 }
 649
 650                 return $this->msg( 'categoryviewer-pagedlinks' )->rawParams( $prevLink, $nextLink )->escaped();
 651         }
 652
 653         /**
 654          * Takes a title, and adds the fragment identifier that
 655          * corresponds to the correct segment of the category.
 656          *
 657          * @param Title $title The title (usually $this->title)
 658          * @param string $section Which section
 659          * @throws MWException
 660          * @return Title
 661          */
 662         private function addFragmentToTitle( $title, $section ) {
 663                 switch ( $section ) {
 664                         case 'page':
 665                                 $fragment = 'mw-pages';
 666                                 break;
 667                         case 'subcat':
 668                                 $fragment = 'mw-subcategories';
 669                                 break;
 670                         case 'file':
 671                                 $fragment = 'mw-category-media';
 672                                 break;
 673                         default:
 674                                 throw new MWException( __METHOD__ .
 675                                         " Invalid section $section." );
 676                 }
 677
 678                 return Title::makeTitle( $title->getNamespace(),
 679                         $title->getDBkey(), $fragment );
 680         }
 681
 682         /**
 683          * What to do if the category table conflicts with the number of results
 684          * returned?  This function says what. Each type is considered independently
 685          * of the other types.
 686          *
 687          * @param int $rescnt The number of items returned by our database query.
 688          * @param int $dbcnt The number of items according to the category table.
 689          * @param string $type 'subcat', 'article', or 'file'
 690          * @return string A message giving the number of items, to output to HTML.
 691          */
 692         private function getCountMessage( $rescnt, $dbcnt, $type ) {
 693                 // There are three cases:
 694                 //   1) The category table figure seems sane.  It might be wrong, but
 695                 //      we can't do anything about it if we don't recalculate it on ev-
 696                 //      ery category view.
 697                 //   2) The category table figure isn't sane, like it's smaller than the
 698                 //      number of actual results, *but* the number of results is less
 699                 //      than $this->limit and there's no offset.  In this case we still
 700                 //      know the right figure.
 701                 //   3) We have no idea.
 702
 703                 // Check if there's a "from" or "until" for anything
 704
 705                 // This is a little ugly, but we seem to use different names
 706                 // for the paging types then for the messages.
 707                 if ( $type === 'article' ) {
 708                         $pagingType = 'page';
 709                 } else {
 710                         $pagingType = $type;
 711                 }
 712
 713                 $fromOrUntil = false;
 714                 if ( ( isset( $this->from[$pagingType] ) && $this->from[$pagingType] !== null ) ||
 715                         ( isset( $this->until[$pagingType] ) && $this->until[$pagingType] !== null )
 716                 ) {
 717                         $fromOrUntil = true;
 718                 }
 719
 720                 if ( $dbcnt == $rescnt ||
 721                         ( ( $rescnt == $this->limit || $fromOrUntil ) && $dbcnt > $rescnt )
 722                 ) {
 723                         // Case 1: seems sane.
 724                         $totalcnt = $dbcnt;
 725                 } elseif ( $rescnt < $this->limit && !$fromOrUntil ) {
 726                         // Case 2: not sane, but salvageable.  Use the number of results.
 727                         // Since there are fewer than 200, we can also take this opportunity
 728                         // to refresh the incorrect category table entry -- which should be
 729                         // quick due to the small number of entries.
 730                         $totalcnt = $rescnt;
 731                         $category = $this->cat;
 732                         wfGetDB( DB_MASTER )->onTransactionIdle( function () use ( $category ) {
 733                                 $category->refreshCounts();
 734                         } );
 735                 } else {
 736                         // Case 3: hopeless.  Don't give a total count at all.
 737                         // Messages: category-subcat-count-limited, category-article-count-limited,
 738                         // category-file-count-limited
 739                         return $this->msg( "category-$type-count-limited" )->numParams( $rescnt )->parseAsBlock();
 740                 }
 741                 // Messages: category-subcat-count, category-article-count, category-file-count
 742                 return $this->msg( "category-$type-count" )->numParams( $rescnt, $totalcnt )->parseAsBlock();
 743         }
 744 }