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         public function __construct(
  45                 LanguageNameUtils $languageNameUtils,
  46                 RedirectLookup $redirectLookup
  47         ) {
  48                 parent::__construct( 'MyLanguage' );
  49                 $this->languageNameUtils = $languageNameUtils;
  50                 $this->redirectLookup = $redirectLookup;
  51         }
  52
  53         /**
  54          * If the special page is a redirect, then get the Title object it redirects to.
  55          * False otherwise.
  56          *
  57          * @param string|null $subpage
  58          * @return Title
  59          */
  60         public function getRedirect( $subpage ) {
  61                 $title = $this->findTitle( $subpage );
  62                 // Go to the main page if given invalid title.
  63                 if ( !$title ) {
  64                         $title = Title::newMainPage();
  65                 }
  66                 return $title;
  67         }
  68
  69         /**
  70          * Find a title.
  71          *
  72          * This may return the base page, e.g. if the UI and
  73          * content language are the same.
  74          *
  75          * Examples, assuming the UI language is fi and the content language
  76          * is en:
  77          * - input Page: returns Page/fi if it exists, otherwise Page
  78          * - input Page/de: returns Page/fi if it exists, otherwise Page/de
  79          * if it exists, otherwise Page
  80          *
  81          * @param string|null $subpage
  82          * @return Title|null
  83          */
  84         public function findTitle( $subpage ) {
  85                 return $this->findTitleInternal( $subpage, false );
  86         }
  87
  88         /**
  89          * Find a title for transclusion. This avoids returning the base
  90          * page if a suitable alternative exists.
  91          *
  92          * Examples, assuming the UI language is fi and the content language
  93          * is en:
  94          * - input Page: returns Page/fi if it exists, otherwise Page/en if
  95          * it exists, otherwise Page
  96          * - input Page/de: returns Page/fi if it exists, otherwise Page/de
  97          * if it exists, otherwise Page/en if it exists, otherwise Page
  98          *
  99          * @param string|null $subpage
 100          * @return Title|null
 101          */
 102         public function findTitleForTransclusion( $subpage ) {
 103                 return $this->findTitleInternal( $subpage, true );
 104         }
 105
 106         /**
 107          * Find a title, depending on the content language and the user's
 108          * interface language.
 109          *
 110          * @param string|null $subpage
 111          * @param bool $forTransclusion
 112          * @return Title|null
 113          */
 114         private function findTitleInternal( $subpage, $forTransclusion ) {
 115                 // base = title without the language code suffix
 116                 // provided = the title as it was given
 117                 $base = $provided = null;
 118                 if ( $subpage !== null ) {
 119                         $provided = Title::newFromText( $subpage );
 120                         $base = $provided;
 121
 122                         if ( $provided && str_contains( $subpage, '/' ) ) {
 123                                 $pos = strrpos( $subpage, '/' );
 124                                 $basepage = substr( $subpage, 0, $pos );
 125                                 $code = substr( $subpage, $pos + 1 );
 126                                 if ( strlen( $code ) && $this->languageNameUtils->isKnownLanguageTag( $code ) ) {
 127                                         $base = Title::newFromText( $basepage );
 128                                 }
 129                         }
 130                 }
 131
 132                 if ( !$base || !$base->canExist() ) {
 133                         // No subpage provided or base page does not exist
 134                         return null;
 135                 }
 136
 137                 $fragment = '';
 138                 if ( $base->isRedirect() ) {
 139                         $target = $this->redirectLookup->getRedirectTarget( $base );
 140                         if ( $target !== null ) {
 141                                 $base = Title::newFromLinkTarget( $target );
 142                                 // Preserve the fragment from the redirect target
 143                                 $fragment = $base->getFragment();
 144                         }
 145                 }
 146
 147                 $uiLang = $this->getLanguage();
 148                 $baseLang = $base->getPageLanguage();
 149
 150                 // T309329: Always use subpages for transclusion
 151                 if ( !$forTransclusion && $baseLang->equals( $uiLang ) ) {
 152                         // Short circuit when the current UI language is the
 153                         // page's content language to avoid unnecessary page lookups.
 154                         return $base;
 155                 }
 156
 157                 // Check for a subpage in the current UI language
 158                 $proposed = $base->getSubpage( $uiLang->getCode() );
 159                 if ( $proposed && $proposed->exists() ) {
 160                         if ( $fragment !== '' ) {
 161                                 $proposed->setFragment( $fragment );
 162                         }
 163                         return $proposed;
 164                 }
 165
 166                 // Explicit language code given and the page exists
 167                 if ( $provided !== $base && $provided->exists() ) {
 168                         // Not based on the redirect target, don't need the fragment
 169                         return $provided;
 170                 }
 171
 172                 // Check for fallback languages specified by the UI language
 173                 $possibilities = $uiLang->getFallbackLanguages();
 174                 foreach ( $possibilities as $lang ) {
 175                         // $base already include fragments
 176                         // T309329: Always use subpages for transclusion
 177                         // T333187: Do not ignore base language page if matched
 178                         if ( !$forTransclusion && $lang === $baseLang->getCode() ) {
 179                                 return $base;
 180                         }
 181                         // Look for subpages if is for transclusion or didn't match base page language
 182                         $proposed = $base->getSubpage( $lang );
 183                         if ( $proposed && $proposed->exists() ) {
 184                                 if ( $fragment !== '' ) {
 185                                         $proposed->setFragment( $fragment );
 186                                 }
 187                                 return $proposed;
 188                         }
 189                 }
 190
 191                 // When all else has failed, return the base page
 192                 return $base;
 193         }
 194
 195         /**
 196          * Target can identify a specific user's language preference.
 197          *
 198          * @see T109724
 199          * @since 1.27
 200          * @return bool
 201          */
 202         public function personallyIdentifiableTarget() {
 203                 return true;
 204         }
 205 }
 206
 207 /**
 208  * Retain the old class name for backwards compatibility.
 209  * @deprecated since 1.41
 210  */
 211 class_alias( SpecialMyLanguage::class, 'SpecialMyLanguage' );