includes/specials/SpecialMyLanguage.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 namespace MediaWiki\Specials;
  22
  23 use MediaWiki\Languages\LanguageNameUtils;
  24 use MediaWiki\Page\RedirectLookup;
  25 use MediaWiki\SpecialPage\RedirectSpecialArticle;
  26 use MediaWiki\Title\Title;
  27
  28 /**
  29  * Redirect to the appropriate translated version of a page if it exists.
  30  *
  31  * Usage: [[Special:MyLanguage/Page name|link text]]
  32  *
  33  * @since 1.24
  34  * @ingroup SpecialPage
  35  * @author Niklas Laxström
  36  * @author Siebrand Mazeland
  37  * @copyright Copyright © 2010-2013 Niklas Laxström, Siebrand Mazeland
  38  */
  39 class SpecialMyLanguage extends RedirectSpecialArticle {
  40
  41         private LanguageNameUtils $languageNameUtils;
  42         private RedirectLookup $redirectLookup;
  43
  44         /**
  45          * @param LanguageNameUtils $languageNameUtils
  46          * @param RedirectLookup $redirectLookup
  47          */
  48         public function __construct(
  49                 LanguageNameUtils $languageNameUtils,
  50                 RedirectLookup $redirectLookup
  51         ) {
  52                 parent::__construct( 'MyLanguage' );
  53                 $this->languageNameUtils = $languageNameUtils;
  54                 $this->redirectLookup = $redirectLookup;
  55         }
  56
  57         /**
  58          * If the special page is a redirect, then get the Title object it redirects to.
  59          * False otherwise.
  60          *
  61          * @param string|null $subpage
  62          * @return Title
  63          */
  64         public function getRedirect( $subpage ) {
  65                 $title = $this->findTitle( $subpage );
  66                 // Go to the main page if given invalid title.
  67                 if ( !$title ) {
  68                         $title = Title::newMainPage();
  69                 }
  70                 return $title;
  71         }
  72
  73         /**
  74          * Find a title.
  75          *
  76          * This may return the base page, e.g. if the UI and
  77          * content language are the same.
  78          *
  79          * Examples, assuming the UI language is fi and the content language
  80          * is en:
  81          * - input Page: returns Page/fi if it exists, otherwise Page
  82          * - input Page/de: returns Page/fi if it exists, otherwise Page/de
  83          * if it exists, otherwise Page
  84          *
  85          * @param string|null $subpage
  86          * @return Title|null
  87          */
  88         public function findTitle( $subpage ) {
  89                 return $this->findTitleInternal( $subpage, false );
  90         }
  91
  92         /**
  93          * Find a title for transclusion. This avoids returning the base
  94          * page if a suitable alternative exists.
  95          *
  96          * Examples, assuming the UI language is fi and the content language
  97          * is en:
  98          * - input Page: returns Page/fi if it exists, otherwise Page/en if
  99          * it exists, otherwise Page
 100          * - input Page/de: returns Page/fi if it exists, otherwise Page/de
 101          * if it exists, otherwise Page/en if it exists, otherwise Page
 102          *
 103          * @param string|null $subpage
 104          * @return Title|null
 105          */
 106         public function findTitleForTransclusion( $subpage ) {
 107                 return $this->findTitleInternal( $subpage, true );
 108         }
 109
 110         /**
 111          * Find a title, depending on the content language and the user's
 112          * interface language.
 113          *
 114          * @param string|null $subpage
 115          * @param bool $forTransclusion
 116          * @return Title|null
 117          */
 118         private function findTitleInternal( $subpage, $forTransclusion ) {
 119                 // base = title without the language code suffix
 120                 // provided = the title as it was given
 121                 $base = $provided = null;
 122                 if ( $subpage !== null ) {
 123                         $provided = Title::newFromText( $subpage );
 124                         $base = $provided;
 125
 126                         if ( $provided && str_contains( $subpage, '/' ) ) {
 127                                 $pos = strrpos( $subpage, '/' );
 128                                 $basepage = substr( $subpage, 0, $pos );
 129                                 $code = substr( $subpage, $pos + 1 );
 130                                 if ( strlen( $code ) && $this->languageNameUtils->isKnownLanguageTag( $code ) ) {
 131                                         $base = Title::newFromText( $basepage );
 132                                 }
 133                         }
 134                 }
 135
 136                 if ( !$base || !$base->canExist() ) {
 137                         // No subpage provided or base page does not exist
 138                         return null;
 139                 }
 140
 141                 $fragment = '';
 142                 if ( $base->isRedirect() ) {
 143                         $target = $this->redirectLookup->getRedirectTarget( $base );
 144                         if ( $target !== null ) {
 145                                 $base = Title::newFromLinkTarget( $target );
 146                                 // Preserve the fragment from the redirect target
 147                                 $fragment = $base->getFragment();
 148                         }
 149                 }
 150
 151                 $uiLang = $this->getLanguage();
 152                 $baseLang = $base->getPageLanguage();
 153
 154                 // T309329: Always use subpages for transclusion
 155                 if ( !$forTransclusion && $baseLang->equals( $uiLang ) ) {
 156                         // Short circuit when the current UI language is the
 157                         // page's content language to avoid unnecessary page lookups.
 158                         return $base;
 159                 }
 160
 161                 // Check for a subpage in the current UI language
 162                 $proposed = $base->getSubpage( $uiLang->getCode() );
 163                 if ( $proposed && $proposed->exists() ) {
 164                         if ( $fragment !== '' ) {
 165                                 $proposed->setFragment( $fragment );
 166                         }
 167                         return $proposed;
 168                 }
 169
 170                 // Explicit language code given and the page exists
 171                 if ( $provided !== $base && $provided->exists() ) {
 172                         // Not based on the redirect target, don't need the fragment
 173                         return $provided;
 174                 }
 175
 176                 // Check for fallback languages specified by the UI language
 177                 $possibilities = $uiLang->getFallbackLanguages();
 178                 foreach ( $possibilities as $lang ) {
 179                         // $base already include fragments
 180                         // T309329: Always use subpages for transclusion
 181                         // T333187: Do not ignore base language page if matched
 182                         if ( !$forTransclusion && $lang === $baseLang->getCode() ) {
 183                                 return $base;
 184                         }
 185                         // Look for subpages if is for transclusion or didn't match base page language
 186                         $proposed = $base->getSubpage( $lang );
 187                         if ( $proposed && $proposed->exists() ) {
 188                                 if ( $fragment !== '' ) {
 189                                         $proposed->setFragment( $fragment );
 190                                 }
 191                                 return $proposed;
 192                         }
 193                 }
 194
 195                 // When all else has failed, return the base page
 196                 return $base;
 197         }
 198
 199         /**
 200          * Target can identify a specific user's language preference.
 201          *
 202          * @see T109724
 203          * @since 1.27
 204          * @return bool
 205          */
 206         public function personallyIdentifiableTarget() {
 207                 return true;
 208         }
 209 }
 210
 211 /**
 212  * Retain the old class name for backwards compatibility.
 213  * @deprecated since 1.41
 214  */
 215 class_alias( SpecialMyLanguage::class, 'SpecialMyLanguage' );