LinkHolderArray.php

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<?php
use MediaWiki\Cache\LinkCache;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Linker\Linker;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Parser\Parser;
use MediaWiki\Title\Title;
 
class LinkHolderArray {
    private $internals = [];
    private $interwikis = [];
    private $size = 0;
    private $parent;
    private $languageConverter;
    private $hookRunner;
 
    public function __construct( Parser $parent, ILanguageConverter $languageConverter,
        HookContainer $hookContainer
    ) {
        $this->parent = $parent;
        $this->languageConverter = $languageConverter;
        $this->hookRunner = new HookRunner( $hookContainer );
    }
 
    public function __destruct() {
        // @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach
        foreach ( $this as $name => $_ ) {
            unset( $this->$name );
        }
    }
 
    public function merge( $other ) {
        foreach ( $other->internals as $ns => $entries ) {
            $this->size += count( $entries );
            if ( !isset( $this->internals[$ns] ) ) {
                $this->internals[$ns] = $entries;
            } else {
                $this->internals[$ns] += $entries;
            }
        }
        $this->interwikis += $other->interwikis;
    }
 
    public function isBig() {
        $linkHolderBatchSize = MediaWikiServices::getInstance()->getMainConfig()
            ->get( MainConfigNames::LinkHolderBatchSize );
        return $this->size > $linkHolderBatchSize;
    }
 
    public function clear() {
        $this->internals = [];
        $this->interwikis = [];
        $this->size = 0;
    }
 
    public function makeHolder( Title $nt, $text = '', $trail = '', $prefix = '' ) {
        # Separate the link trail from the rest of the link
        [ $inside, $trail ] = Linker::splitTrail( $trail );
 
        $key = $this->parent->nextLinkID();
        $entry = [
            'title' => $nt,
            'text' => $prefix . $text . $inside,
            'pdbk' => $nt->getPrefixedDBkey(),
        ];
 
        $this->size++;
        if ( $nt->isExternal() ) {
            // Use a globally unique ID to keep the objects mergable
            $this->interwikis[$key] = $entry;
            return "<!--IWLINK'\" $key-->{$trail}";
        } else {
            $ns = $nt->getNamespace();
            $this->internals[$ns][$key] = $entry;
            return "<!--LINK'\" $ns:$key-->{$trail}";
        }
    }
 
    public function replace( &$text ) {
        $this->replaceInternal( $text );
        $this->replaceInterwiki( $text );
    }
 
    protected function replaceInternal( &$text ) {
        if ( !$this->internals ) {
            return;
        }
 
        $classes = [];
        $services = MediaWikiServices::getInstance();
        $linkCache = $services->getLinkCache();
        $output = $this->parent->getOutput();
        $linkRenderer = $this->parent->getLinkRenderer();
 
        $dbr = $services->getConnectionProvider()->getReplicaDatabase();
 
        # Sort by namespace
        ksort( $this->internals );
 
        $pagemap = [];
 
        # Generate query
        $linkBatchFactory = $services->getLinkBatchFactory();
        $lb = $linkBatchFactory->newLinkBatch();
        $lb->setCaller( __METHOD__ );
 
        foreach ( $this->internals as $ns => $entries ) {
            foreach ( $entries as [ 'title' => $title, 'pdbk' => $pdbk ] ) {
                # Check if it's a static known link, e.g. interwiki
                if ( $title->isAlwaysKnown() ) {
                    $classes[$pdbk] = '';
                } elseif ( $ns === NS_SPECIAL ) {
                    $classes[$pdbk] = 'new';
                } else {
                    $id = $linkCache->getGoodLinkID( $pdbk );
                    if ( $id ) {
                        $classes[$pdbk] = $linkRenderer->getLinkClasses( $title );
                        $output->addLink( $title, $id );
                        $pagemap[$id] = $pdbk;
                    } elseif ( $linkCache->isBadLink( $pdbk ) ) {
                        $classes[$pdbk] = 'new';
                    } else {
                        # Not in the link cache, add it to the query
                        $lb->addObj( $title );
                    }
                }
            }
        }
        if ( !$lb->isEmpty() ) {
            $res = $dbr->newSelectQueryBuilder()
                ->select( LinkCache::getSelectFields() )
                ->from( 'page' )
                ->where( [ $lb->constructSet( 'page', $dbr ) ] )
                ->caller( __METHOD__ )
                ->fetchResultSet();
 
            # Fetch data and form into an associative array
            # non-existent = broken
            foreach ( $res as $s ) {
                $title = Title::makeTitle( $s->page_namespace, $s->page_title );
                $pdbk = $title->getPrefixedDBkey();
                $linkCache->addGoodLinkObjFromRow( $title, $s );
                $output->addLink( $title, $s->page_id );
                $classes[$pdbk] = $linkRenderer->getLinkClasses( $title );
                // add id to the extension todolist
                $pagemap[$s->page_id] = $pdbk;
            }
            unset( $res );
        }
        if ( $pagemap !== [] ) {
            // pass an array of page_ids to an extension
            $this->hookRunner->onGetLinkColours( $pagemap, $classes, $this->parent->getTitle() );
        }
 
        # Do a second query for different language variants of links and categories
        if ( $this->languageConverter->hasVariants() ) {
            $this->doVariants( $classes );
        }
 
        # Construct search and replace arrays
        $replacePairs = [];
        foreach ( $this->internals as $ns => $entries ) {
            foreach ( $entries as $index => $entry ) {
                $pdbk = $entry['pdbk'];
                $title = $entry['title'];
                $query = $entry['query'] ?? [];
                $searchkey = "$ns:$index";
                $displayTextHtml = $entry['text'];
                if ( isset( $entry['selflink'] ) ) {
                    $replacePairs[$searchkey] = Linker::makeSelfLinkObj( $title, $displayTextHtml, $query );
                    continue;
                }
 
                $displayText = $displayTextHtml === '' ? null : new HtmlArmor( $displayTextHtml );
                if ( !isset( $classes[$pdbk] ) ) {
                    $classes[$pdbk] = 'new';
                }
                if ( $classes[$pdbk] === 'new' ) {
                    $linkCache->addBadLinkObj( $title );
                    $output->addLink( $title, 0 );
                    $link = $linkRenderer->makeBrokenLink(
                        $title, $displayText, [], $query
                    );
                } else {
                    $link = $linkRenderer->makePreloadedLink(
                        $title, $displayText, $classes[$pdbk], [], $query
                    );
                }
 
                $replacePairs[$searchkey] = $link;
            }
        }
 
        # Do the thing
        $text = preg_replace_callback(
            '/<!--LINK\'" (-?[\d:]+)-->/',
            static function ( array $matches ) use ( $replacePairs ) {
                return $replacePairs[$matches[1]];
            },
            $text
        );
    }
 
    protected function replaceInterwiki( &$text ) {
        if ( !$this->interwikis ) {
            return;
        }
 
        # Make interwiki link HTML
        $output = $this->parent->getOutput();
        $replacePairs = [];
        $linkRenderer = $this->parent->getLinkRenderer();
        foreach ( $this->interwikis as $key => [ 'title' => $title, 'text' => $linkText ] ) {
            $replacePairs[$key] = $linkRenderer->makeLink( $title, new HtmlArmor( $linkText ) );
            $output->addInterwikiLink( $title );
        }
 
        $text = preg_replace_callback(
            '/<!--IWLINK\'" (\d+)-->/',
            static function ( array $matches ) use ( $replacePairs ) {
                return $replacePairs[$matches[1]];
            },
            $text
        );
    }
 
    protected function doVariants( &$classes ) {
        $linkBatchFactory = MediaWikiServices::getInstance()->getLinkBatchFactory();
        $linkBatch = $linkBatchFactory->newLinkBatch();
        $variantMap = []; // maps $pdbkey_Variant => $keys (of link holders)
        $output = $this->parent->getOutput();
        $titlesToBeConverted = '';
        $titlesAttrs = [];
 
        // Concatenate titles to a single string, thus we only need auto convert the
        // single string to all variants. This would improve parser's performance
        // significantly.
        foreach ( $this->internals as $ns => $entries ) {
            if ( $ns === NS_SPECIAL ) {
                continue;
            }
            foreach ( $entries as $index => [ 'title' => $title, 'pdbk' => $pdbk ] ) {
                // we only deal with new links (in its first query)
                if ( !isset( $classes[$pdbk] ) || $classes[$pdbk] === 'new' ) {
                    $titlesAttrs[] = [ $index, $title ];
                    // separate titles with \0 because it would never appears
                    // in a valid title
                    $titlesToBeConverted .= $title->getText() . "\0";
                }
            }
        }
 
        // Now do the conversion and explode string to text of titles
        $titlesAllVariants = $this->languageConverter->
            autoConvertToAllVariants( rtrim( $titlesToBeConverted, "\0" ) );
        foreach ( $titlesAllVariants as &$titlesVariant ) {
            $titlesVariant = explode( "\0", $titlesVariant );
        }
 
        // Then add variants of links to link batch
        $parentTitle = $this->parent->getTitle();
        foreach ( $titlesAttrs as $i => [ $index, $title ] ) {
            $ns = $title->getNamespace();
            $text = $title->getText();
 
            foreach ( $titlesAllVariants as $textVariants ) {
                $textVariant = $textVariants[$i];
                if ( $textVariant === $text ) {
                    continue;
                }
 
                $variantTitle = Title::makeTitle( $ns, $textVariant );
 
                // Self-link checking for mixed/different variant titles. At this point, we
                // already know the exact title does not exist, so the link cannot be to a
                // variant of the current title that exists as a separate page.
                if ( $variantTitle->equals( $parentTitle ) && !$title->hasFragment() ) {
                    $this->internals[$ns][$index]['selflink'] = true;
                    continue 2;
                }
 
                $linkBatch->addObj( $variantTitle );
                $variantMap[$variantTitle->getPrefixedDBkey()][] = "$ns:$index";
            }
        }
 
        // process categories, check if a category exists in some variant
        $categoryMap = []; // maps $category_variant => $category (dbkeys)
        foreach ( $output->getCategoryNames() as $category ) {
            $categoryTitle = Title::makeTitleSafe( NS_CATEGORY, $category );
            $linkBatch->addObj( $categoryTitle );
            $variants = $this->languageConverter->autoConvertToAllVariants( $category );
            foreach ( $variants as $variant ) {
                if ( $variant !== $category ) {
                    $variantTitle = Title::makeTitleSafe( NS_CATEGORY, $variant );
                    if ( $variantTitle ) {
                        $linkBatch->addObj( $variantTitle );
                        $categoryMap[$variant] = [ $category, $categoryTitle ];
                    }
                }
            }
        }
 
        if ( $linkBatch->isEmpty() ) {
            return;
        }
 
        // construct query
        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
 
        $varRes = $dbr->newSelectQueryBuilder()
            ->select( LinkCache::getSelectFields() )
            ->from( 'page' )
            ->where( [ $linkBatch->constructSet( 'page', $dbr ) ] )
            ->caller( __METHOD__ )
            ->fetchResultSet();
 
        $pagemap = [];
        $varCategories = [];
        $linkCache = MediaWikiServices::getInstance()->getLinkCache();
        $linkRenderer = $this->parent->getLinkRenderer();
 
        // for each found variants, figure out link holders and replace
        foreach ( $varRes as $s ) {
            $variantTitle = Title::makeTitle( $s->page_namespace, $s->page_title );
            $varPdbk = $variantTitle->getPrefixedDBkey();
 
            if ( !isset( $variantMap[$varPdbk] ) ) {
                continue;
            }
 
            $linkCache->addGoodLinkObjFromRow( $variantTitle, $s );
            $output->addLink( $variantTitle, $s->page_id );
 
            // loop over link holders
            foreach ( $variantMap[$varPdbk] as $key ) {
                [ $ns, $index ] = explode( ':', $key, 2 );
                $entry =& $this->internals[(int)$ns][(int)$index];
                $pdbk = $entry['pdbk'];
 
                if ( !isset( $classes[$pdbk] ) || $classes[$pdbk] === 'new' ) {
                    // found link in some of the variants, replace the link holder data
                    $entry['title'] = $variantTitle;
                    $entry['pdbk'] = $varPdbk;
 
                    // set pdbk and colour if we haven't checked this title yet.
                    if ( !isset( $classes[$varPdbk] ) ) {
                        $classes[$varPdbk] = $linkRenderer->getLinkClasses( $variantTitle );
                        $pagemap[$s->page_id] = $varPdbk;
                    }
                }
            }
 
            // check if the object is a variant of a category
            $vardbk = $variantTitle->getDBkey();
            if ( isset( $categoryMap[$vardbk] ) ) {
                [ $oldkey, $oldtitle ] = $categoryMap[$vardbk];
                if ( !isset( $varCategories[$oldkey] ) && !$oldtitle->exists() ) {
                    $varCategories[$oldkey] = $vardbk;
                }
            }
        }
        $this->hookRunner->onGetLinkColours( $pagemap, $classes, $this->parent->getTitle() );
 
        // rebuild the categories in original order (if there are replacements)
        if ( $varCategories !== [] ) {
            $newCats = [];
            foreach ( $output->getCategoryNames() as $cat ) {
                $sortkey = $output->getCategorySortKey( $cat );
                // make the replacement
                $newCats[$varCategories[$cat] ?? $cat] = $sortkey;
            }
            $output->setCategories( $newCats );
        }
    }
 
    public function replaceText( $text ) {
        return preg_replace_callback(
            '/<!--(IW)?LINK\'" (-?[\d:]+)-->/',
            function ( $matches ) {
                [ $unchanged, $isInterwiki, $key ] = $matches;
 
                if ( !$isInterwiki ) {
                    [ $ns, $index ] = explode( ':', $key, 2 );
                    return $this->internals[(int)$ns][(int)$index]['text'] ?? $unchanged;
                } else {
                    return $this->interwikis[$key]['text'] ?? $unchanged;
                }
            },
            $text
        );
    }
}