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[mediawiki.git] / includes / linker / LinkRenderer.php

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @license GPL-2.0+
 * @author Kunal Mehta <legoktm@member.fsf.org>
 */
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 that generates HTML <a> links for pages.
 *
 * @see https://www.mediawiki.org/wiki/Manual:LinkRenderer
 * @since 1.28
 */
class LinkRenderer {

        /**
         * Whether to force the pretty article path
         *
         * @var bool
         */
        private $forceArticlePath = false;

        /**
         * A PROTO_* constant or false
         *
         * @var string|bool|int
         */
        private $expandUrls = false;

        /**
         * @var int
         */
        private $stubThreshold = 0;

        /**
         * @var TitleFormatter
         */
        private $titleFormatter;

        /**
         * @var LinkCache
         */
        private $linkCache;

        /**
         * Whether to run the legacy Linker hooks
         *
         * @var bool
         */
        private $runLegacyBeginHook = true;

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

        /**
         * @param bool $force
         */
        public function setForceArticlePath( $force ) {
                $this->forceArticlePath = $force;
        }

        /**
         * @return bool
         */
        public function getForceArticlePath() {
                return $this->forceArticlePath;
        }

        /**
         * @param string|bool|int $expand A PROTO_* constant or false
         */
        public function setExpandURLs( $expand ) {
                $this->expandUrls = $expand;
        }

        /**
         * @return string|bool|int a PROTO_* constant or false
         */
        public function getExpandURLs() {
                return $this->expandUrls;
        }

        /**
         * @param int $threshold
         */
        public function setStubThreshold( $threshold ) {
                $this->stubThreshold = $threshold;
        }

        /**
         * @return int
         */
        public function getStubThreshold() {
                return $this->stubThreshold;
        }

        /**
         * @param bool $run
         */
        public function setRunLegacyBeginHook( $run ) {
                $this->runLegacyBeginHook = $run;
        }

        /**
         * @param LinkTarget $target
         * @param string|HtmlArmor|null $text
         * @param array $extraAttribs
         * @param array $query
         * @return string
         */
        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 );
                }
        }

        /**
         * Get the options in the legacy format
         *
         * @param bool $isKnown Whether the link is known or broken
         * @return array
         */
        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;
        }

        /**
         * If you have already looked up the proper CSS classes using LinkRenderer::getLinkClasses()
         * or some other method, use this to avoid looking it up again.
         *
         * @param LinkTarget $target
         * @param string|HtmlArmor|null $text
         * @param string $classes CSS classes to add
         * @param array $extraAttribs
         * @param array $query
         * @return string
         */
        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 );
        }

        /**
         * @param LinkTarget $target
         * @param string|HtmlArmor|null $text
         * @param array $extraAttribs
         * @param array $query
         * @return string
         */
        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
                );
        }

        /**
         * @param LinkTarget $target
         * @param string|HtmlArmor|null $text
         * @param array $extraAttribs
         * @param array $query
         * @return string
         */
        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 );
        }

        /**
         * Builds the final <a> element
         *
         * @param LinkTarget $target
         * @param string|HtmlArmor $text
         * @param array $attribs
         * @param bool $isKnown
         * @return null|string
         */
        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 );
        }

        /**
         * @param LinkTarget $target
         * @return string non-escaped text
         */
        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;
        }

        /**
         * Normalizes the provided target
         *
         * @todo move the code from Linker actually here
         * @param LinkTarget $target
         * @return LinkTarget
         */
        private function normalizeTarget( LinkTarget $target ) {
                return Linker::normaliseSpecialPage( $target );
        }

        /**
         * Merges two sets of attributes
         *
         * @param array $defaults
         * @param array $attribs
         *
         * @return array
         */
        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;
        }

        /**
         * Return the CSS classes of a known link
         *
         * @param LinkTarget $target
         * @return string CSS class
         */
        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 '';
        }
}