LinkRenderer.php

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<?php
namespace MediaWiki\Linker;

use DummyLinker;
use Hooks;
use Html;
use HtmlArmor;
use LinkCache;
use Linker;
use MediaWiki\MediaWikiServices;
use MWNamespace;
use Sanitizer;
use Title;
use TitleFormatter;

class LinkRenderer {

    private $forceArticlePath = false;

    private $expandUrls = false;

    private $stubThreshold = 0;

    private $titleFormatter;

    private $linkCache;

    private $runLegacyBeginHook = true;

    public function __construct( TitleFormatter $titleFormatter, LinkCache $linkCache ) {
        $this->titleFormatter = $titleFormatter;
        $this->linkCache = $linkCache;
    }

    public function setForceArticlePath( $force ) {
        $this->forceArticlePath = $force;
    }

    public function getForceArticlePath() {
        return $this->forceArticlePath;
    }

    public function setExpandURLs( $expand ) {
        $this->expandUrls = $expand;
    }

    public function getExpandURLs() {
        return $this->expandUrls;
    }

    public function setStubThreshold( $threshold ) {
        $this->stubThreshold = $threshold;
    }

    public function getStubThreshold() {
        return $this->stubThreshold;
    }

    public function setRunLegacyBeginHook( $run ) {
        $this->runLegacyBeginHook = $run;
    }

    public function makeLink(
        LinkTarget $target, $text = null, array $extraAttribs = [], array $query = []
    ) {
        $title = Title::newFromLinkTarget( $target );
        if ( $title->isKnown() ) {
            return $this->makeKnownLink( $target, $text, $extraAttribs, $query );
        } else {
            return $this->makeBrokenLink( $target, $text, $extraAttribs, $query );
        }
    }

    private function getLegacyOptions( $isKnown ) {
        $options = [ 'stubThreshold' => $this->stubThreshold ];
        if ( $this->forceArticlePath ) {
            $options[] = 'forcearticlepath';
        }
        if ( $this->expandUrls === PROTO_HTTP ) {
            $options[] = 'http';
        } elseif ( $this->expandUrls === PROTO_HTTPS ) {
            $options[] = 'https';
        }

        $options[] = $isKnown ? 'known' : 'broken';

        return $options;
    }

    private function runBeginHook( LinkTarget $target, &$text, &$extraAttribs, &$query, $isKnown ) {
        $ret = null;
        if ( !Hooks::run( 'HtmlPageLinkRendererBegin',
            [ $this, $target, &$text, &$extraAttribs, &$query, &$ret ] )
        ) {
            return $ret;
        }

        // Now run the legacy hook
        return $this->runLegacyBeginHook( $target, $text, $extraAttribs, $query, $isKnown );
    }

    private function runLegacyBeginHook( LinkTarget $target, &$text, &$extraAttribs, &$query,
        $isKnown
    ) {
        if ( !$this->runLegacyBeginHook || !Hooks::isRegistered( 'LinkBegin' ) ) {
            // Disabled, or nothing registered
            return null;
        }

        $realOptions = $options = $this->getLegacyOptions( $isKnown );
        $ret = null;
        $dummy = new DummyLinker();
        $title = Title::newFromLinkTarget( $target );
        if ( $text !== null ) {
            $realHtml = $html = HtmlArmor::getHtml( $text );
        } else {
            $realHtml = $html = null;
        }
        if ( !Hooks::run( 'LinkBegin',
            [ $dummy, $title, &$html, &$extraAttribs, &$query, &$options, &$ret ] )
        ) {
            return $ret;
        }

        if ( $html !== null && $html !== $realHtml ) {
            // &$html was modified, so re-armor it as $text
            $text = new HtmlArmor( $html );
        }

        // Check if they changed any of the options, hopefully not!
        if ( $options !== $realOptions ) {
            $factory = MediaWikiServices::getInstance()->getLinkRendererFactory();
            // They did, so create a separate instance and have that take over the rest
            $newRenderer = $factory->createFromLegacyOptions( $options );
            // Don't recurse the hook...
            $newRenderer->setRunLegacyBeginHook( false );
            if ( in_array( 'known', $options, true ) ) {
                return $newRenderer->makeKnownLink( $title, $text, $extraAttribs, $query );
            } elseif ( in_array( 'broken', $options, true ) ) {
                return $newRenderer->makeBrokenLink( $title, $text, $extraAttribs, $query );
            } else {
                return $newRenderer->makeLink( $title, $text, $extraAttribs, $query );
            }
        }

        return null;
    }

    public function makePreloadedLink(
        LinkTarget $target, $text = null, $classes, array $extraAttribs = [], array $query = []
    ) {
        // Run begin hook
        $ret = $this->runBeginHook( $target, $text, $extraAttribs, $query, true );
        if ( $ret !== null ) {
            return $ret;
        }
        $target = $this->normalizeTarget( $target );
        $url = $this->getLinkURL( $target, $query );
        $attribs = [ 'class' => $classes ];
        $prefixedText = $this->titleFormatter->getPrefixedText( $target );
        if ( $prefixedText !== '' ) {
            $attribs['title'] = $prefixedText;
        }

        $attribs = [
            'href' => $url,
        ] + $this->mergeAttribs( $attribs, $extraAttribs );

        if ( $text === null ) {
            $text = $this->getLinkText( $target );
        }

        return $this->buildAElement( $target, $text, $attribs, true );
    }

    public function makeKnownLink(
        LinkTarget $target, $text = null, array $extraAttribs = [], array $query = []
    ) {
        $classes = [];
        if ( $target->isExternal() ) {
            $classes[] = 'extiw';
        }
        $colour = $this->getLinkClasses( $target );
        if ( $colour !== '' ) {
            $classes[] = $colour;
        }

        return $this->makePreloadedLink(
            $target,
            $text,
            $classes ? implode( ' ', $classes ) : '',
            $extraAttribs,
            $query
        );
    }

    public function makeBrokenLink(
        LinkTarget $target, $text = null, array $extraAttribs = [], array $query = []
    ) {
        // Run legacy hook
        $ret = $this->runBeginHook( $target, $text, $extraAttribs, $query, false );
        if ( $ret !== null ) {
            return $ret;
        }

        # We don't want to include fragments for broken links, because they
        # generally make no sense.
        if ( $target->hasFragment() ) {
            $target = $target->createFragmentTarget( '' );
        }
        $target = $this->normalizeTarget( $target );

        if ( !isset( $query['action'] ) && $target->getNamespace() !== NS_SPECIAL ) {
            $query['action'] = 'edit';
            $query['redlink'] = '1';
        }

        $url = $this->getLinkURL( $target, $query );
        $attribs = [ 'class' => 'new' ];
        $prefixedText = $this->titleFormatter->getPrefixedText( $target );
        if ( $prefixedText !== '' ) {
            // This ends up in parser cache!
            $attribs['title'] = wfMessage( 'red-link-title', $prefixedText )
                ->inContentLanguage()
                ->text();
        }

        $attribs = [
            'href' => $url,
        ] + $this->mergeAttribs( $attribs, $extraAttribs );

        if ( $text === null ) {
            $text = $this->getLinkText( $target );
        }

        return $this->buildAElement( $target, $text, $attribs, false );
    }

    private function buildAElement( LinkTarget $target, $text, array $attribs, $isKnown ) {
        $ret = null;
        if ( !Hooks::run( 'HtmlPageLinkRendererEnd',
            [ $this, $target, $isKnown, &$text, &$attribs, &$ret ] )
        ) {
            return $ret;
        }

        $html = HtmlArmor::getHtml( $text );

        // Run legacy hook
        if ( Hooks::isRegistered( 'LinkEnd' ) ) {
            $dummy = new DummyLinker();
            $title = Title::newFromLinkTarget( $target );
            $options = $this->getLegacyOptions( $isKnown );
            if ( !Hooks::run( 'LinkEnd',
                [ $dummy, $title, $options, &$html, &$attribs, &$ret ] )
            ) {
                return $ret;
            }
        }

        return Html::rawElement( 'a', $attribs, $html );
    }

    private function getLinkText( LinkTarget $target ) {
        $prefixedText = $this->titleFormatter->getPrefixedText( $target );
        // If the target is just a fragment, with no title, we return the fragment
        // text.  Otherwise, we return the title text itself.
        if ( $prefixedText === '' && $target->hasFragment() ) {
            return $target->getFragment();
        }

        return $prefixedText;
    }

    private function getLinkURL( LinkTarget $target, array $query = [] ) {
        // TODO: Use a LinkTargetResolver service instead of Title
        $title = Title::newFromLinkTarget( $target );
        if ( $this->forceArticlePath ) {
            $realQuery = $query;
            $query = [];
        } else {
            $realQuery = [];
        }
        $url = $title->getLinkURL( $query, false, $this->expandUrls );

        if ( $this->forceArticlePath && $realQuery ) {
            $url = wfAppendQuery( $url, $realQuery );
        }

        return $url;
    }

    private function normalizeTarget( LinkTarget $target ) {
        return Linker::normaliseSpecialPage( $target );
    }

    private function mergeAttribs( $defaults, $attribs ) {
        if ( !$attribs ) {
            return $defaults;
        }
        # Merge the custom attribs with the default ones, and iterate
        # over that, deleting all "false" attributes.
        $ret = [];
        $merged = Sanitizer::mergeAttributes( $defaults, $attribs );
        foreach ( $merged as $key => $val ) {
            # A false value suppresses the attribute
            if ( $val !== false ) {
                $ret[$key] = $val;
            }
        }
        return $ret;
    }

    public function getLinkClasses( LinkTarget $target ) {
        // Make sure the target is in the cache
        $id = $this->linkCache->addLinkObj( $target );
        if ( $id == 0 ) {
            // Doesn't exist
            return '';
        }

        if ( $this->linkCache->getGoodLinkFieldObj( $target, 'redirect' ) ) {
            # Page is a redirect
            return 'mw-redirect';
        } elseif ( $this->stubThreshold > 0 && MWNamespace::isContent( $target->getNamespace() )
            && $this->linkCache->getGoodLinkFieldObj( $target, 'length' ) < $this->stubThreshold
        ) {
            # Page is a stub
            return 'stub';
        }

        return '';
    }
}