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 );
 158                         } catch ( MWException $e ) {
 159                                 // User specified something invalid, fallback to default.
 160                                 $this->gallery = ImageGalleryBase::factory();
 161                         }
 162
 163                         $this->gallery->setHideBadImages();
 164                         $this->gallery->setContext( $this->getContext() );
 165                 } else {
 166                         $this->imgsNoGallery = array();
 167                         $this->imgsNoGallery_start_char = array();
 168                 }
 169         }
 170
 171         /**
 172          * Add a subcategory to the internal lists, using a Category object
 173          * @param Category $cat
 174          * @param string $sortkey
 175          * @param int $pageLength
 176          */
 177         function addSubcategoryObject( Category $cat, $sortkey, $pageLength ) {
 178                 // Subcategory; strip the 'Category' namespace from the link text.
 179                 $title = $cat->getTitle();
 180
 181                 $link = Linker::link( $title, htmlspecialchars( $title->getText() ) );
 182                 if ( $title->isRedirect() ) {
 183                         // This didn't used to add redirect-in-category, but might
 184                         // as well be consistent with the rest of the sections
 185                         // on a category page.
 186                         $link = '<span class="redirect-in-category">' . $link . '</span>';
 187                 }
 188                 $this->children[] = $link;
 189
 190                 $this->children_start_char[] =
 191                         $this->getSubcategorySortChar( $cat->getTitle(), $sortkey );
 192         }
 193
 194         /**
 195          * Get the character to be used for sorting subcategories.
 196          * If there's a link from Category:A to Category:B, the sortkey of the resulting
 197          * entry in the categorylinks table is Category:A, not A, which it SHOULD be.
 198          * Workaround: If sortkey == "Category:".$title, than use $title for sorting,
 199          * else use sortkey...
 200          *
 201          * @param Title $title
 202          * @param string $sortkey The human-readable sortkey (before transforming to icu or whatever).
 203          * @return string
 204          */
 205         function getSubcategorySortChar( $title, $sortkey ) {
 206                 global $wgContLang;
 207
 208                 if ( $title->getPrefixedText() == $sortkey ) {
 209                         $word = $title->getDBkey();
 210                 } else {
 211                         $word = $sortkey;
 212                 }
 213
 214                 $firstChar = $this->collation->getFirstLetter( $word );
 215
 216                 return $wgContLang->convert( $firstChar );
 217         }
 218
 219         /**
 220          * Add a page in the image namespace
 221          * @param Title $title
 222          * @param string $sortkey
 223          * @param int $pageLength
 224          * @param bool $isRedirect
 225          */
 226         function addImage( Title $title, $sortkey, $pageLength, $isRedirect = false ) {
 227                 global $wgContLang;
 228                 if ( $this->showGallery ) {
 229                         $flip = $this->flip['file'];
 230                         if ( $flip ) {
 231                                 $this->gallery->insert( $title );
 232                         } else {
 233                                 $this->gallery->add( $title );
 234                         }
 235                 } else {
 236                         $link = Linker::link( $title );
 237                         if ( $isRedirect ) {
 238                                 // This seems kind of pointless given 'mw-redirect' class,
 239                                 // but keeping for back-compatibility with user css.
 240                                 $link = '<span class="redirect-in-category">' . $link . '</span>';
 241                         }
 242                         $this->imgsNoGallery[] = $link;
 243
 244                         $this->imgsNoGallery_start_char[] = $wgContLang->convert(
 245                                 $this->collation->getFirstLetter( $sortkey ) );
 246                 }
 247         }
 248
 249         /**
 250          * Add a miscellaneous page
 251          * @param Title $title
 252          * @param string $sortkey
 253          * @param int $pageLength
 254          * @param bool $isRedirect
 255          */
 256         function addPage( $title, $sortkey, $pageLength, $isRedirect = false ) {
 257                 global $wgContLang;
 258
 259                 $link = Linker::link( $title );
 260                 if ( $isRedirect ) {
 261                         // This seems kind of pointless given 'mw-redirect' class,
 262                         // but keeping for back-compatibility with user css.
 263                         $link = '<span class="redirect-in-category">' . $link . '</span>';
 264                 }
 265                 $this->articles[] = $link;
 266
 267                 $this->articles_start_char[] = $wgContLang->convert(
 268                         $this->collation->getFirstLetter( $sortkey ) );
 269         }
 270
 271         function finaliseCategoryState() {
 272                 if ( $this->flip['subcat'] ) {
 273                         $this->children = array_reverse( $this->children );
 274                         $this->children_start_char = array_reverse( $this->children_start_char );
 275                 }
 276                 if ( $this->flip['page'] ) {
 277                         $this->articles = array_reverse( $this->articles );
 278                         $this->articles_start_char = array_reverse( $this->articles_start_char );
 279                 }
 280                 if ( !$this->showGallery && $this->flip['file'] ) {
 281                         $this->imgsNoGallery = array_reverse( $this->imgsNoGallery );
 282                         $this->imgsNoGallery_start_char = array_reverse( $this->imgsNoGallery_start_char );
 283                 }
 284         }
 285
 286         function doCategoryQuery() {
 287                 $dbr = wfGetDB( DB_SLAVE, 'category' );
 288
 289                 $this->nextPage = array(
 290                         'page' => null,
 291                         'subcat' => null,
 292                         'file' => null,
 293                 );
 294                 $this->prevPage = array(
 295                         'page' => null,
 296                         'subcat' => null,
 297                         'file' => null,
 298                 );
 299
 300                 $this->flip = array( 'page' => false, 'subcat' => false, 'file' => false );
 301
 302                 foreach ( array( 'page', 'subcat', 'file' ) as $type ) {
 303                         # Get the sortkeys for start/end, if applicable.  Note that if
 304                         # the collation in the database differs from the one
 305                         # set in $wgCategoryCollation, pagination might go totally haywire.
 306                         $extraConds = array( 'cl_type' => $type );
 307                         if ( isset( $this->from[$type] ) && $this->from[$type] !== null ) {
 308                                 $extraConds[] = 'cl_sortkey >= '
 309                                         . $dbr->addQuotes( $this->collation->getSortKey( $this->from[$type] ) );
 310                         } elseif ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
 311                                 $extraConds[] = 'cl_sortkey < '
 312                                         . $dbr->addQuotes( $this->collation->getSortKey( $this->until[$type] ) );
 313                                 $this->flip[$type] = true;
 314                         }
 315
 316                         $res = $dbr->select(
 317                                 array( 'page', 'categorylinks', 'category' ),
 318                                 array( 'page_id', 'page_title', 'page_namespace', 'page_len',
 319                                         'page_is_redirect', 'cl_sortkey', 'cat_id', 'cat_title',
 320                                         'cat_subcats', 'cat_pages', 'cat_files',
 321                                         'cl_sortkey_prefix', 'cl_collation' ),
 322                                 array_merge( array( 'cl_to' => $this->title->getDBkey() ), $extraConds ),
 323                                 __METHOD__,
 324                                 array(
 325                                         'USE INDEX' => array( 'categorylinks' => 'cl_sortkey' ),
 326                                         'LIMIT' => $this->limit + 1,
 327                                         'ORDER BY' => $this->flip[$type] ? 'cl_sortkey DESC' : 'cl_sortkey',
 328                                 ),
 329                                 array(
 330                                         'categorylinks' => array( 'INNER JOIN', 'cl_from = page_id' ),
 331                                         'category' => array( 'LEFT JOIN', array(
 332                                                 'cat_title = page_title',
 333                                                 'page_namespace' => NS_CATEGORY
 334                                         ))
 335                                 )
 336                         );
 337
 338                         $count = 0;
 339                         foreach ( $res as $row ) {
 340                                 $title = Title::newFromRow( $row );
 341                                 if ( $row->cl_collation === '' ) {
 342                                         // Hack to make sure that while updating from 1.16 schema
 343                                         // and db is inconsistent, that the sky doesn't fall.
 344                                         // See r83544. Could perhaps be removed in a couple decades...
 345                                         $humanSortkey = $row->cl_sortkey;
 346                                 } else {
 347                                         $humanSortkey = $title->getCategorySortkey( $row->cl_sortkey_prefix );
 348                                 }
 349
 350                                 if ( ++$count > $this->limit ) {
 351                                         # We've reached the one extra which shows that there
 352                                         # are additional pages to be had. Stop here...
 353                                         $this->nextPage[$type] = $humanSortkey;
 354                                         break;
 355                                 }
 356                                 if ( $count == $this->limit ) {
 357                                         $this->prevPage[$type] = $humanSortkey;
 358                                 }
 359
 360                                 if ( $title->getNamespace() == NS_CATEGORY ) {
 361                                         $cat = Category::newFromRow( $row, $title );
 362                                         $this->addSubcategoryObject( $cat, $humanSortkey, $row->page_len );
 363                                 } elseif ( $title->getNamespace() == NS_FILE ) {
 364                                         $this->addImage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
 365                                 } else {
 366                                         $this->addPage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
 367                                 }
 368                         }
 369                 }
 370         }
 371
 372         /**
 373          * @return string
 374          */
 375         function getCategoryTop() {
 376                 $r = $this->getCategoryBottom();
 377                 return $r === ''
 378                         ? $r
 379                         : "<br style=\"clear:both;\"/>\n" . $r;
 380         }
 381
 382         /**
 383          * @return string
 384          */
 385         function getSubcategorySection() {
 386                 # Don't show subcategories section if there are none.
 387                 $r = '';
 388                 $rescnt = count( $this->children );
 389                 $dbcnt = $this->cat->getSubcatCount();
 390                 $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'subcat' );
 391
 392                 if ( $rescnt > 0 ) {
 393                         # Showing subcategories
 394                         $r .= "<div id=\"mw-subcategories\">\n";
 395                         $r .= '<h2>' . $this->msg( 'subcategories' )->text() . "</h2>\n";
 396                         $r .= $countmsg;
 397                         $r .= $this->getSectionPagingLinks( 'subcat' );
 398                         $r .= $this->formatList( $this->children, $this->children_start_char );
 399                         $r .= $this->getSectionPagingLinks( 'subcat' );
 400                         $r .= "\n</div>";
 401                 }
 402                 return $r;
 403         }
 404
 405         /**
 406          * @return string
 407          */
 408         function getPagesSection() {
 409                 $ti = wfEscapeWikiText( $this->title->getText() );
 410                 # Don't show articles section if there are none.
 411                 $r = '';
 412
 413                 # @todo FIXME: Here and in the other two sections: we don't need to bother
 414                 # with this rigmarole if the entire category contents fit on one page
 415                 # and have already been retrieved.  We can just use $rescnt in that
 416                 # case and save a query and some logic.
 417                 $dbcnt = $this->cat->getPageCount() - $this->cat->getSubcatCount()
 418                         - $this->cat->getFileCount();
 419                 $rescnt = count( $this->articles );
 420                 $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'article' );
 421
 422                 if ( $rescnt > 0 ) {
 423                         $r = "<div id=\"mw-pages\">\n";
 424                         $r .= '<h2>' . $this->msg( 'category_header', $ti )->text() . "</h2>\n";
 425                         $r .= $countmsg;
 426                         $r .= $this->getSectionPagingLinks( 'page' );
 427                         $r .= $this->formatList( $this->articles, $this->articles_start_char );
 428                         $r .= $this->getSectionPagingLinks( 'page' );
 429                         $r .= "\n</div>";
 430                 }
 431                 return $r;
 432         }
 433
 434         /**
 435          * @return string
 436          */
 437         function getImageSection() {
 438                 $r = '';
 439                 $rescnt = $this->showGallery ? $this->gallery->count() : count( $this->imgsNoGallery );
 440                 if ( $rescnt > 0 ) {
 441                         $dbcnt = $this->cat->getFileCount();
 442                         $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'file' );
 443
 444                         $r .= "<div id=\"mw-category-media\">\n";
 445                         $r .= '<h2>' .
 446                                 $this->msg(
 447                                         'category-media-header',
 448                                         wfEscapeWikiText( $this->title->getText() )
 449                                 )->text() .
 450                                 "</h2>\n";
 451                         $r .= $countmsg;
 452                         $r .= $this->getSectionPagingLinks( 'file' );
 453                         if ( $this->showGallery ) {
 454                                 $r .= $this->gallery->toHTML();
 455                         } else {
 456                                 $r .= $this->formatList( $this->imgsNoGallery, $this->imgsNoGallery_start_char );
 457                         }
 458                         $r .= $this->getSectionPagingLinks( 'file' );
 459                         $r .= "\n</div>";
 460                 }
 461                 return $r;
 462         }
 463
 464         /**
 465          * Get the paging links for a section (subcats/pages/files), to go at the top and bottom
 466          * of the output.
 467          *
 468          * @param string $type 'page', 'subcat', or 'file'
 469          * @return string HTML output, possibly empty if there are no other pages
 470          */
 471         private function getSectionPagingLinks( $type ) {
 472                 if ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
 473                         // The new value for the until parameter should be pointing to the first
 474                         // result displayed on the page which is the second last result retrieved
 475                         // from the database.The next link should have a from parameter pointing
 476                         // to the until parameter of the current page.
 477                         if ( $this->nextPage[$type] !== null ) {
 478                                 return $this->pagingLinks( $this->prevPage[$type], $this->until[$type], $type );
 479                         } else {
 480                                 // If the nextPage variable is null, it means that we have reached the first page
 481                                 // and therefore the previous link should be disabled.
 482                                 return $this->pagingLinks( null, $this->until[$type], $type );
 483                         }
 484                 } elseif ( $this->nextPage[$type] !== null
 485                         || ( isset( $this->from[$type] ) && $this->from[$type] !== null )
 486                 ) {
 487                         return $this->pagingLinks( $this->from[$type], $this->nextPage[$type], $type );
 488                 } else {
 489                         return '';
 490                 }
 491         }
 492
 493         /**
 494          * @return string
 495          */
 496         function getCategoryBottom() {
 497                 return '';
 498         }
 499
 500         /**
 501          * Format a list of articles chunked by letter, either as a
 502          * bullet list or a columnar format, depending on the length.
 503          *
 504          * @param array $articles
 505          * @param array $articles_start_char
 506          * @param int $cutoff
 507          * @return string
 508          * @private
 509          */
 510         function formatList( $articles, $articles_start_char, $cutoff = 6 ) {
 511                 $list = '';
 512                 if ( count( $articles ) > $cutoff ) {
 513                         $list = self::columnList( $articles, $articles_start_char );
 514                 } elseif ( count( $articles ) > 0 ) {
 515                         // for short lists of articles in categories.
 516                         $list = self::shortList( $articles, $articles_start_char );
 517                 }
 518
 519                 $pageLang = $this->title->getPageLanguage();
 520                 $attribs = array( 'lang' => $pageLang->getCode(), 'dir' => $pageLang->getDir(),
 521                         'class' => 'mw-content-' . $pageLang->getDir() );
 522                 $list = Html::rawElement( 'div', $attribs, $list );
 523
 524                 return $list;
 525         }
 526
 527         /**
 528          * Format a list of articles chunked by letter in a three-column
 529          * list, ordered vertically.
 530          *
 531          * TODO: Take the headers into account when creating columns, so they're
 532          * more visually equal.
 533          *
 534          * More distant TODO: Scrap this and use CSS columns, whenever IE finally
 535          * supports those.
 536          *
 537          * @param array $articles
 538          * @param string[] $articles_start_char
 539          * @return string
 540          * @private
 541          */
 542         static function columnList( $articles, $articles_start_char ) {
 543                 $columns = array_combine( $articles, $articles_start_char );
 544                 # Split into three columns
 545                 $columns = array_chunk( $columns, ceil( count( $columns ) / 3 ), true /* preserve keys */ );
 546
 547                 $ret = '<table style="width: 100%;"><tr style="vertical-align: top;">';
 548                 $prevchar = null;
 549
 550                 foreach ( $columns as $column ) {
 551                         $ret .= '<td style="width: 33.3%;">';
 552                         $colContents = array();
 553
 554                         # Kind of like array_flip() here, but we keep duplicates in an
 555                         # array instead of dropping them.
 556                         foreach ( $column as $article => $char ) {
 557                                 if ( !isset( $colContents[$char] ) ) {
 558                                         $colContents[$char] = array();
 559                                 }
 560                                 $colContents[$char][] = $article;
 561                         }
 562
 563                         $first = true;
 564                         foreach ( $colContents as $char => $articles ) {
 565                                 # Change space to non-breaking space to keep headers aligned
 566                                 $h3char = $char === ' ' ? '&#160;' : htmlspecialchars( $char );
 567
 568                                 $ret .= '<h3>' . $h3char;
 569                                 if ( $first && $char === $prevchar ) {
 570                                         # We're continuing a previous chunk at the top of a new
 571                                         # column, so add " cont." after the letter.
 572                                         $ret .= ' ' . wfMessage( 'listingcontinuesabbrev' )->escaped();
 573                                 }
 574                                 $ret .= "</h3>\n";
 575
 576                                 $ret .= '<ul><li>';
 577                                 $ret .= implode( "</li>\n<li>", $articles );
 578                                 $ret .= '</li></ul>';
 579
 580                                 $first = false;
 581                                 $prevchar = $char;
 582                         }
 583
 584                         $ret .= "</td>\n";
 585                 }
 586
 587                 $ret .= '</tr></table>';
 588                 return $ret;
 589         }
 590
 591         /**
 592          * Format a list of articles chunked by letter in a bullet list.
 593          * @param array $articles
 594          * @param string[] $articles_start_char
 595          * @return string
 596          * @private
 597          */
 598         static function shortList( $articles, $articles_start_char ) {
 599                 $r = '<h3>' . htmlspecialchars( $articles_start_char[0] ) . "</h3>\n";
 600                 $r .= '<ul><li>' . $articles[0] . '</li>';
 601                 $articleCount = count( $articles );
 602                 for ( $index = 1; $index < $articleCount; $index++ ) {
 603                         if ( $articles_start_char[$index] != $articles_start_char[$index - 1] ) {
 604                                 $r .= "</ul><h3>" . htmlspecialchars( $articles_start_char[$index] ) . "</h3>\n<ul>";
 605                         }
 606
 607                         $r .= "<li>{$articles[$index]}</li>";
 608                 }
 609                 $r .= '</ul>';
 610                 return $r;
 611         }
 612
 613         /**
 614          * Create paging links, as a helper method to getSectionPagingLinks().
 615          *
 616          * @param string $first The 'until' parameter for the generated URL
 617          * @param string $last The 'from' parameter for the generated URL
 618          * @param string $type A prefix for parameters, 'page' or 'subcat' or
 619          *     'file'
 620          * @return string HTML
 621          */
 622         private function pagingLinks( $first, $last, $type = '' ) {
 623                 $prevLink = $this->msg( 'prevn' )->numParams( $this->limit )->escaped();
 624
 625                 if ( $first != '' ) {
 626                         $prevQuery = $this->query;
 627                         $prevQuery["{$type}until"] = $first;
 628                         unset( $prevQuery["{$type}from"] );
 629                         $prevLink = Linker::linkKnown(
 630                                 $this->addFragmentToTitle( $this->title, $type ),
 631                                 $prevLink,
 632                                 array(),
 633                                 $prevQuery
 634                         );
 635                 }
 636
 637                 $nextLink = $this->msg( 'nextn' )->numParams( $this->limit )->escaped();
 638
 639                 if ( $last != '' ) {
 640                         $lastQuery = $this->query;
 641                         $lastQuery["{$type}from"] = $last;
 642                         unset( $lastQuery["{$type}until"] );
 643                         $nextLink = Linker::linkKnown(
 644                                 $this->addFragmentToTitle( $this->title, $type ),
 645                                 $nextLink,
 646                                 array(),
 647                                 $lastQuery
 648                         );
 649                 }
 650
 651                 return $this->msg( 'categoryviewer-pagedlinks' )->rawParams( $prevLink, $nextLink )->escaped();
 652         }
 653
 654         /**
 655          * Takes a title, and adds the fragment identifier that
 656          * corresponds to the correct segment of the category.
 657          *
 658          * @param Title $title The title (usually $this->title)
 659          * @param string $section Which section
 660          * @throws MWException
 661          * @return Title
 662          */
 663         private function addFragmentToTitle( $title, $section ) {
 664                 switch ( $section ) {
 665                         case 'page':
 666                                 $fragment = 'mw-pages';
 667                                 break;
 668                         case 'subcat':
 669                                 $fragment = 'mw-subcategories';
 670                                 break;
 671                         case 'file':
 672                                 $fragment = 'mw-category-media';
 673                                 break;
 674                         default:
 675                                 throw new MWException( __METHOD__ .
 676                                         " Invalid section $section." );
 677                 }
 678
 679                 return Title::makeTitle( $title->getNamespace(),
 680                         $title->getDBkey(), $fragment );
 681         }
 682
 683         /**
 684          * What to do if the category table conflicts with the number of results
 685          * returned?  This function says what. Each type is considered independently
 686          * of the other types.
 687          *
 688          * @param int $rescnt The number of items returned by our database query.
 689          * @param int $dbcnt The number of items according to the category table.
 690          * @param string $type 'subcat', 'article', or 'file'
 691          * @return string A message giving the number of items, to output to HTML.
 692          */
 693         private function getCountMessage( $rescnt, $dbcnt, $type ) {
 694                 // There are three cases:
 695                 //   1) The category table figure seems sane.  It might be wrong, but
 696                 //      we can't do anything about it if we don't recalculate it on ev-
 697                 //      ery category view.
 698                 //   2) The category table figure isn't sane, like it's smaller than the
 699                 //      number of actual results, *but* the number of results is less
 700                 //      than $this->limit and there's no offset.  In this case we still
 701                 //      know the right figure.
 702                 //   3) We have no idea.
 703
 704                 // Check if there's a "from" or "until" for anything
 705
 706                 // This is a little ugly, but we seem to use different names
 707                 // for the paging types then for the messages.
 708                 if ( $type === 'article' ) {
 709                         $pagingType = 'page';
 710                 } else {
 711                         $pagingType = $type;
 712                 }
 713
 714                 $fromOrUntil = false;
 715                 if ( ( isset( $this->from[$pagingType] ) && $this->from[$pagingType] !== null ) ||
 716                         ( isset( $this->until[$pagingType] ) && $this->until[$pagingType] !== null )
 717                 ) {
 718                         $fromOrUntil = true;
 719                 }
 720
 721                 if ( $dbcnt == $rescnt ||
 722                         ( ( $rescnt == $this->limit || $fromOrUntil ) && $dbcnt > $rescnt )
 723                 ) {
 724                         // Case 1: seems sane.
 725                         $totalcnt = $dbcnt;
 726                 } elseif ( $rescnt < $this->limit && !$fromOrUntil ) {
 727                         // Case 2: not sane, but salvageable.  Use the number of results.
 728                         // Since there are fewer than 200, we can also take this opportunity
 729                         // to refresh the incorrect category table entry -- which should be
 730                         // quick due to the small number of entries.
 731                         $totalcnt = $rescnt;
 732                         $category = $this->cat;
 733                         wfGetDB( DB_MASTER )->onTransactionIdle( function () use ( $category ) {
 734                                 $category->refreshCounts();
 735                         } );
 736                 } else {
 737                         // Case 3: hopeless.  Don't give a total count at all.
 738                         // Messages: category-subcat-count-limited, category-article-count-limited,
 739                         // category-file-count-limited
 740                         return $this->msg( "category-$type-count-limited" )->numParams( $rescnt )->parseAsBlock();
 741                 }
 742                 // Messages: category-subcat-count, category-article-count, category-file-count
 743                 return $this->msg( "category-$type-count" )->numParams( $rescnt, $totalcnt )->parseAsBlock();
 744         }
 745 }