CategoryViewer.php

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<?php
use MediaWiki\MediaWikiServices;

class CategoryViewer extends ContextSource {
    public $limit;

    public $from;

    public $until;

    public $articles;

    public $articles_start_char;

    public $children;

    public $children_start_char;

    public $showGallery;

    public $imgsNoGallery_start_char;

    public $imgsNoGallery;

    public $nextPage;

    protected $prevPage;

    public $flip;

    public $title;

    public $collation;

    public $gallery;

    private $cat;

    private $query;

    function __construct( $title, IContextSource $context, $from = [],
        $until = [], $query = []
    ) {
        $this->title = $title;
        $this->setContext( $context );
        $this->getOutput()->addModuleStyles( [
            'mediawiki.action.view.categoryPage.styles'
        ] );
        $this->from = $from;
        $this->until = $until;
        $this->limit = $context->getConfig()->get( 'CategoryPagingLimit' );
        $this->cat = Category::newFromTitle( $title );
        $this->query = $query;
        $this->collation = Collation::singleton();
        unset( $this->query['title'] );
    }

    public function getHTML() {

        $this->showGallery = $this->getConfig()->get( 'CategoryMagicGallery' )
            && !$this->getOutput()->mNoGallery;

        $this->clearCategoryState();
        $this->doCategoryQuery();
        $this->finaliseCategoryState();

        $r = $this->getSubcategorySection() .
            $this->getPagesSection() .
            $this->getImageSection();

        if ( $r == '' ) {
            // If there is no category content to display, only
            // show the top part of the navigation links.
            // @todo FIXME: Cannot be completely suppressed because it
            //        is unknown if 'until' or 'from' makes this
            //        give 0 results.
            $r = $r . $this->getCategoryTop();
        } else {
            $r = $this->getCategoryTop() .
                $r .
                $this->getCategoryBottom();
        }

        // Give a proper message if category is empty
        if ( $r == '' ) {
            $r = $this->msg( 'category-empty' )->parseAsBlock();
        }

        $lang = $this->getLanguage();
        $attribs = [
            'class' => 'mw-category-generated',
            'lang' => $lang->getHtmlCode(),
            'dir' => $lang->getDir()
        ];
        # put a div around the headings which are in the user language
        $r = Html::openElement( 'div', $attribs ) . $r . '</div>';

        return $r;
    }

    function clearCategoryState() {
        $this->articles = [];
        $this->articles_start_char = [];
        $this->children = [];
        $this->children_start_char = [];
        if ( $this->showGallery ) {
            // Note that null for mode is taken to mean use default.
            $mode = $this->getRequest()->getVal( 'gallerymode', null );
            try {
                $this->gallery = ImageGalleryBase::factory( $mode, $this->getContext() );
            } catch ( Exception $e ) {
                // User specified something invalid, fallback to default.
                $this->gallery = ImageGalleryBase::factory( false, $this->getContext() );
            }

            $this->gallery->setHideBadImages();
        } else {
            $this->imgsNoGallery = [];
            $this->imgsNoGallery_start_char = [];
        }
    }

    function addSubcategoryObject( Category $cat, $sortkey, $pageLength ) {
        // Subcategory; strip the 'Category' namespace from the link text.
        $title = $cat->getTitle();

        $this->children[] = $this->generateLink(
            'subcat',
            $title,
            $title->isRedirect(),
            htmlspecialchars( $title->getText() )
        );

        $this->children_start_char[] =
            $this->getSubcategorySortChar( $cat->getTitle(), $sortkey );
    }

    function generateLink( $type, Title $title, $isRedirect, $html = null ) {
        $link = null;
        Hooks::run( 'CategoryViewer::generateLink', [ $type, $title, $html, &$link ] );
        if ( $link === null ) {
            $link = Linker::link( $title, $html );
        }
        if ( $isRedirect ) {
            $link = '<span class="redirect-in-category">' . $link . '</span>';
        }

        return $link;
    }

    function getSubcategorySortChar( $title, $sortkey ) {
        global $wgContLang;

        if ( $title->getPrefixedText() == $sortkey ) {
            $word = $title->getDBkey();
        } else {
            $word = $sortkey;
        }

        $firstChar = $this->collation->getFirstLetter( $word );

        return $wgContLang->convert( $firstChar );
    }

    function addImage( Title $title, $sortkey, $pageLength, $isRedirect = false ) {
        global $wgContLang;
        if ( $this->showGallery ) {
            $flip = $this->flip['file'];
            if ( $flip ) {
                $this->gallery->insert( $title );
            } else {
                $this->gallery->add( $title );
            }
        } else {
            $this->imgsNoGallery[] = $this->generateLink( 'image', $title, $isRedirect );

            $this->imgsNoGallery_start_char[] = $wgContLang->convert(
                $this->collation->getFirstLetter( $sortkey ) );
        }
    }

    function addPage( $title, $sortkey, $pageLength, $isRedirect = false ) {
        global $wgContLang;

        $this->articles[] = $this->generateLink( 'page', $title, $isRedirect );

        $this->articles_start_char[] = $wgContLang->convert(
            $this->collation->getFirstLetter( $sortkey ) );
    }

    function finaliseCategoryState() {
        if ( $this->flip['subcat'] ) {
            $this->children = array_reverse( $this->children );
            $this->children_start_char = array_reverse( $this->children_start_char );
        }
        if ( $this->flip['page'] ) {
            $this->articles = array_reverse( $this->articles );
            $this->articles_start_char = array_reverse( $this->articles_start_char );
        }
        if ( !$this->showGallery && $this->flip['file'] ) {
            $this->imgsNoGallery = array_reverse( $this->imgsNoGallery );
            $this->imgsNoGallery_start_char = array_reverse( $this->imgsNoGallery_start_char );
        }
    }

    function doCategoryQuery() {
        $dbr = wfGetDB( DB_REPLICA, 'category' );

        $this->nextPage = [
            'page' => null,
            'subcat' => null,
            'file' => null,
        ];
        $this->prevPage = [
            'page' => null,
            'subcat' => null,
            'file' => null,
        ];

        $this->flip = [ 'page' => false, 'subcat' => false, 'file' => false ];

        foreach ( [ 'page', 'subcat', 'file' ] as $type ) {
            # Get the sortkeys for start/end, if applicable.  Note that if
            # the collation in the database differs from the one
            # set in $wgCategoryCollation, pagination might go totally haywire.
            $extraConds = [ 'cl_type' => $type ];
            if ( isset( $this->from[$type] ) && $this->from[$type] !== null ) {
                $extraConds[] = 'cl_sortkey >= '
                    . $dbr->addQuotes( $this->collation->getSortKey( $this->from[$type] ) );
            } elseif ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
                $extraConds[] = 'cl_sortkey < '
                    . $dbr->addQuotes( $this->collation->getSortKey( $this->until[$type] ) );
                $this->flip[$type] = true;
            }

            $res = $dbr->select(
                [ 'page', 'categorylinks', 'category' ],
                array_merge(
                    LinkCache::getSelectFields(),
                    [
                        'page_namespace',
                        'page_title',
                        'cl_sortkey',
                        'cat_id',
                        'cat_title',
                        'cat_subcats',
                        'cat_pages',
                        'cat_files',
                        'cl_sortkey_prefix',
                        'cl_collation'
                    ]
                ),
                array_merge( [ 'cl_to' => $this->title->getDBkey() ], $extraConds ),
                __METHOD__,
                [
                    'USE INDEX' => [ 'categorylinks' => 'cl_sortkey' ],
                    'LIMIT' => $this->limit + 1,
                    'ORDER BY' => $this->flip[$type] ? 'cl_sortkey DESC' : 'cl_sortkey',
                ],
                [
                    'categorylinks' => [ 'INNER JOIN', 'cl_from = page_id' ],
                    'category' => [ 'LEFT JOIN', [
                        'cat_title = page_title',
                        'page_namespace' => NS_CATEGORY
                    ] ]
                ]
            );

            Hooks::run( 'CategoryViewer::doCategoryQuery', [ $type, $res ] );
            $linkCache = MediaWikiServices::getInstance()->getLinkCache();

            $count = 0;
            foreach ( $res as $row ) {
                $title = Title::newFromRow( $row );
                $linkCache->addGoodLinkObjFromRow( $title, $row );

                if ( $row->cl_collation === '' ) {
                    // Hack to make sure that while updating from 1.16 schema
                    // and db is inconsistent, that the sky doesn't fall.
                    // See r83544. Could perhaps be removed in a couple decades...
                    $humanSortkey = $row->cl_sortkey;
                } else {
                    $humanSortkey = $title->getCategorySortkey( $row->cl_sortkey_prefix );
                }

                if ( ++$count > $this->limit ) {
                    # We've reached the one extra which shows that there
                    # are additional pages to be had. Stop here...
                    $this->nextPage[$type] = $humanSortkey;
                    break;
                }
                if ( $count == $this->limit ) {
                    $this->prevPage[$type] = $humanSortkey;
                }

                if ( $title->getNamespace() == NS_CATEGORY ) {
                    $cat = Category::newFromRow( $row, $title );
                    $this->addSubcategoryObject( $cat, $humanSortkey, $row->page_len );
                } elseif ( $title->getNamespace() == NS_FILE ) {
                    $this->addImage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
                } else {
                    $this->addPage( $title, $humanSortkey, $row->page_len, $row->page_is_redirect );
                }
            }
        }
    }

    function getCategoryTop() {
        $r = $this->getCategoryBottom();
        return $r === ''
            ? $r
            : "<br style=\"clear:both;\"/>\n" . $r;
    }

    function getSubcategorySection() {
        # Don't show subcategories section if there are none.
        $r = '';
        $rescnt = count( $this->children );
        $dbcnt = $this->cat->getSubcatCount();
        // This function should be called even if the result isn't used, it has side-effects
        $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'subcat' );

        if ( $rescnt > 0 ) {
            # Showing subcategories
            $r .= "<div id=\"mw-subcategories\">\n";
            $r .= '<h2>' . $this->msg( 'subcategories' )->parse() . "</h2>\n";
            $r .= $countmsg;
            $r .= $this->getSectionPagingLinks( 'subcat' );
            $r .= $this->formatList( $this->children, $this->children_start_char );
            $r .= $this->getSectionPagingLinks( 'subcat' );
            $r .= "\n</div>";
        }
        return $r;
    }

    function getPagesSection() {
        $ti = wfEscapeWikiText( $this->title->getText() );
        # Don't show articles section if there are none.
        $r = '';

        # @todo FIXME: Here and in the other two sections: we don't need to bother
        # with this rigmarole if the entire category contents fit on one page
        # and have already been retrieved.  We can just use $rescnt in that
        # case and save a query and some logic.
        $dbcnt = $this->cat->getPageCount() - $this->cat->getSubcatCount()
            - $this->cat->getFileCount();
        $rescnt = count( $this->articles );
        // This function should be called even if the result isn't used, it has side-effects
        $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'article' );

        if ( $rescnt > 0 ) {
            $r = "<div id=\"mw-pages\">\n";
            $r .= '<h2>' . $this->msg( 'category_header', $ti )->parse() . "</h2>\n";
            $r .= $countmsg;
            $r .= $this->getSectionPagingLinks( 'page' );
            $r .= $this->formatList( $this->articles, $this->articles_start_char );
            $r .= $this->getSectionPagingLinks( 'page' );
            $r .= "\n</div>";
        }
        return $r;
    }

    function getImageSection() {
        $r = '';
        $rescnt = $this->showGallery ? $this->gallery->count() : count( $this->imgsNoGallery );
        $dbcnt = $this->cat->getFileCount();
        // This function should be called even if the result isn't used, it has side-effects
        $countmsg = $this->getCountMessage( $rescnt, $dbcnt, 'file' );

        if ( $rescnt > 0 ) {
            $r .= "<div id=\"mw-category-media\">\n";
            $r .= '<h2>' .
                $this->msg(
                    'category-media-header',
                    wfEscapeWikiText( $this->title->getText() )
                )->text() .
                "</h2>\n";
            $r .= $countmsg;
            $r .= $this->getSectionPagingLinks( 'file' );
            if ( $this->showGallery ) {
                $r .= $this->gallery->toHTML();
            } else {
                $r .= $this->formatList( $this->imgsNoGallery, $this->imgsNoGallery_start_char );
            }
            $r .= $this->getSectionPagingLinks( 'file' );
            $r .= "\n</div>";
        }
        return $r;
    }

    private function getSectionPagingLinks( $type ) {
        if ( isset( $this->until[$type] ) && $this->until[$type] !== null ) {
            // The new value for the until parameter should be pointing to the first
            // result displayed on the page which is the second last result retrieved
            // from the database.The next link should have a from parameter pointing
            // to the until parameter of the current page.
            if ( $this->nextPage[$type] !== null ) {
                return $this->pagingLinks( $this->prevPage[$type], $this->until[$type], $type );
            } else {
                // If the nextPage variable is null, it means that we have reached the first page
                // and therefore the previous link should be disabled.
                return $this->pagingLinks( null, $this->until[$type], $type );
            }
        } elseif ( $this->nextPage[$type] !== null
            || ( isset( $this->from[$type] ) && $this->from[$type] !== null )
        ) {
            return $this->pagingLinks( $this->from[$type], $this->nextPage[$type], $type );
        } else {
            return '';
        }
    }

    function getCategoryBottom() {
        return '';
    }

    function formatList( $articles, $articles_start_char, $cutoff = 6 ) {
        $list = '';
        if ( count( $articles ) > $cutoff ) {
            $list = self::columnList( $articles, $articles_start_char );
        } elseif ( count( $articles ) > 0 ) {
            // for short lists of articles in categories.
            $list = self::shortList( $articles, $articles_start_char );
        }

        $pageLang = $this->title->getPageLanguage();
        $attribs = [ 'lang' => $pageLang->getHtmlCode(), 'dir' => $pageLang->getDir(),
            'class' => 'mw-content-' . $pageLang->getDir() ];
        $list = Html::rawElement( 'div', $attribs, $list );

        return $list;
    }

    static function columnList( $articles, $articles_start_char ) {
        $columns = array_combine( $articles, $articles_start_char );

        $ret = Html::openElement( 'div', [ 'class' => 'mw-category' ] );

        $colContents = [];

        # Kind of like array_flip() here, but we keep duplicates in an
        # array instead of dropping them.
        foreach ( $columns as $article => $char ) {
            if ( !isset( $colContents[$char] ) ) {
                $colContents[$char] = [];
            }
            $colContents[$char][] = $article;
        }

        foreach ( $colContents as $char => $articles ) {
            # Change space to non-breaking space to keep headers aligned
            $h3char = $char === ' ' ? '&#160;' : htmlspecialchars( $char );

            $ret .= '<div class="mw-category-group"><h3>' . $h3char;
            $ret .= "</h3>\n";

            $ret .= '<ul><li>';
            $ret .= implode( "</li>\n<li>", $articles );
            $ret .= '</li></ul></div>';

        }

        $ret .= Html::closeElement( 'div' );
        return $ret;
    }

    static function shortList( $articles, $articles_start_char ) {
        $r = '<h3>' . htmlspecialchars( $articles_start_char[0] ) . "</h3>\n";
        $r .= '<ul><li>' . $articles[0] . '</li>';
        $articleCount = count( $articles );
        for ( $index = 1; $index < $articleCount; $index++ ) {
            if ( $articles_start_char[$index] != $articles_start_char[$index - 1] ) {
                $r .= "</ul><h3>" . htmlspecialchars( $articles_start_char[$index] ) . "</h3>\n<ul>";
            }

            $r .= "<li>{$articles[$index]}</li>";
        }
        $r .= '</ul>';
        return $r;
    }

    private function pagingLinks( $first, $last, $type = '' ) {
        $prevLink = $this->msg( 'prev-page' )->text();

        if ( $first != '' ) {
            $prevQuery = $this->query;
            $prevQuery["{$type}until"] = $first;
            unset( $prevQuery["{$type}from"] );
            $prevLink = Linker::linkKnown(
                $this->addFragmentToTitle( $this->title, $type ),
                $prevLink,
                [],
                $prevQuery
            );
        }

        $nextLink = $this->msg( 'next-page' )->text();

        if ( $last != '' ) {
            $lastQuery = $this->query;
            $lastQuery["{$type}from"] = $last;
            unset( $lastQuery["{$type}until"] );
            $nextLink = Linker::linkKnown(
                $this->addFragmentToTitle( $this->title, $type ),
                $nextLink,
                [],
                $lastQuery
            );
        }

        return $this->msg( 'categoryviewer-pagedlinks' )->rawParams( $prevLink, $nextLink )->escaped();
    }

    private function addFragmentToTitle( $title, $section ) {
        switch ( $section ) {
            case 'page':
                $fragment = 'mw-pages';
                break;
            case 'subcat':
                $fragment = 'mw-subcategories';
                break;
            case 'file':
                $fragment = 'mw-category-media';
                break;
            default:
                throw new MWException( __METHOD__ .
                    " Invalid section $section." );
        }

        return Title::makeTitle( $title->getNamespace(),
            $title->getDBkey(), $fragment );
    }

    private function getCountMessage( $rescnt, $dbcnt, $type ) {
        // There are three cases:
        //   1) The category table figure seems sane.  It might be wrong, but
        //      we can't do anything about it if we don't recalculate it on ev-
        //      ery category view.
        //   2) The category table figure isn't sane, like it's smaller than the
        //      number of actual results, *but* the number of results is less
        //      than $this->limit and there's no offset.  In this case we still
        //      know the right figure.
        //   3) We have no idea.

        // Check if there's a "from" or "until" for anything

        // This is a little ugly, but we seem to use different names
        // for the paging types then for the messages.
        if ( $type === 'article' ) {
            $pagingType = 'page';
        } else {
            $pagingType = $type;
        }

        $fromOrUntil = false;
        if ( ( isset( $this->from[$pagingType] ) && $this->from[$pagingType] !== null ) ||
            ( isset( $this->until[$pagingType] ) && $this->until[$pagingType] !== null )
        ) {
            $fromOrUntil = true;
        }

        if ( $dbcnt == $rescnt ||
            ( ( $rescnt == $this->limit || $fromOrUntil ) && $dbcnt > $rescnt )
        ) {
            // Case 1: seems sane.
            $totalcnt = $dbcnt;
        } elseif ( $rescnt < $this->limit && !$fromOrUntil ) {
            // Case 2: not sane, but salvageable.  Use the number of results.
            // Since there are fewer than 200, we can also take this opportunity
            // to refresh the incorrect category table entry -- which should be
            // quick due to the small number of entries.
            $totalcnt = $rescnt;
            $category = $this->cat;
            DeferredUpdates::addCallableUpdate( function () use ( $category ) {
                $category->refreshCounts();
            } );
        } else {
            // Case 3: hopeless.  Don't give a total count at all.
            // Messages: category-subcat-count-limited, category-article-count-limited,
            // category-file-count-limited
            return $this->msg( "category-$type-count-limited" )->numParams( $rescnt )->parseAsBlock();
        }
        // Messages: category-subcat-count, category-article-count, category-file-count
        return $this->msg( "category-$type-count" )->numParams( $rescnt, $totalcnt )->parseAsBlock();
    }
}