includes/Revision/RevisionStoreCacheRecord.php

   1 <?php
   2 /**
   3  * A RevisionStoreRecord loaded from the cache.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 namespace MediaWiki\Revision;
  24
  25 use MediaWiki\User\UserIdentity;
  26 use MediaWiki\User\UserIdentityValue;
  27 use CommentStoreComment;
  28 use InvalidArgumentException;
  29 use Title;
  30 use User;
  31
  32 /**
  33  * A cached RevisionStoreRecord.  Ensures that changes performed "behind the back"
  34  * of the cache do not cause the revision record to deliver stale data.
  35  *
  36  * @since 1.33
  37  */
  38 class RevisionStoreCacheRecord extends RevisionStoreRecord {
  39
  40         /**
  41          * @var callable
  42          */
  43         private $mCallback;
  44
  45         /**
  46          * @note Avoid calling this constructor directly. Use the appropriate methods
  47          * in RevisionStore instead.
  48          *
  49          * @param callable $callback Callback for loading data.  Signature: function ( $id ): object
  50          * @param Title $title The title of the page this Revision is associated with.
  51          * @param UserIdentity $user
  52          * @param CommentStoreComment $comment
  53          * @param object $row A row from the revision table. Use RevisionStore::getQueryInfo() to build
  54          *        a query that yields the required fields.
  55          * @param RevisionSlots $slots The slots of this revision.
  56          * @param bool|string $dbDomain DB domain of the relevant wiki or false for the current one.
  57          */
  58         function __construct(
  59                 $callback,
  60                 Title $title,
  61                 UserIdentity $user,
  62                 CommentStoreComment $comment,
  63                 $row,
  64                 RevisionSlots $slots,
  65                 $dbDomain = false
  66         ) {
  67                 parent::__construct( $title, $user, $comment, $row, $slots, $dbDomain );
  68                 $this->mCallback = $callback;
  69         }
  70
  71         /**
  72          * Overridden to ensure that we return a fresh value and not a cached one.
  73          *
  74          * @return int
  75          */
  76         public function getVisibility() {
  77                 if ( $this->mCallback ) {
  78                         $this->loadFreshRow();
  79                 }
  80                 return parent::getVisibility();
  81         }
  82
  83         /**
  84          * Overridden to ensure that we return a fresh value and not a cached one.
  85          *
  86          * @param int $audience
  87          * @param User|null $user
  88          *
  89          * @return UserIdentity The identity of the revision author, null if access is forbidden.
  90          */
  91         public function getUser( $audience = self::FOR_PUBLIC, User $user = null ) {
  92                 if ( $this->mCallback ) {
  93                         $this->loadFreshRow();
  94                 }
  95                 return parent::getUser( $audience, $user );
  96         }
  97
  98         /**
  99          * Load a fresh row from the database to ensure we return updated information
 100
 101          * @throws RevisionAccessException if the row could not be loaded
 102          */
 103         private function loadFreshRow() {
 104                 $freshRow = call_user_func( $this->mCallback, $this->mId );
 105
 106                 // Set to null to ensure we do not make unnecessary queries for subsequent getter calls,
 107                 // and to allow the closure to be freed.
 108                 $this->mCallback = null;
 109
 110                 if ( $freshRow ) {
 111                         $this->mDeleted = intval( $freshRow->rev_deleted );
 112
 113                         try {
 114                                 $this->mUser = User::newFromAnyId(
 115                                         $freshRow->rev_user ?? null,
 116                                         $freshRow->rev_user_text ?? null,
 117                                         $freshRow->rev_actor ?? null
 118                                 );
 119                         } catch ( InvalidArgumentException $ex ) {
 120                                 wfWarn(
 121                                         __METHOD__
 122                                         . ': '
 123                                         . $this->mTitle->getPrefixedDBkey()
 124                                         . ': '
 125                                         . $ex->getMessage()
 126                                 );
 127                                 $this->mUser = new UserIdentityValue( 0, 'Unknown user', 0 );
 128                         }
 129                 } else {
 130                         throw new RevisionAccessException(
 131                                 'Unable to load fresh row for rev_id: ' . $this->mId
 132                         );
 133                 }
 134         }
 135
 136 }