DifferenceEngine cleanup

[mediawiki.git] / includes / WatchedItem.php

<?php
/**
 * Accessor and mutator for watchlist entries.
 *
 * 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
 * @ingroup Watchlist
 */

/**
 * Representation of a pair of user and title for watchlist entries.
 *
 * @ingroup Watchlist
 */
class WatchedItem {
        /**
         * Constant to specify that user rights 'editmywatchlist' and
         * 'viewmywatchlist' should not be checked.
         * @since 1.22
         */
        const IGNORE_USER_RIGHTS = 0;

        /**
         * Constant to specify that user rights 'editmywatchlist' and
         * 'viewmywatchlist' should be checked.
         * @since 1.22
         */
        const CHECK_USER_RIGHTS = 1;

        var $mTitle, $mUser, $mCheckRights;
        private $loaded = false, $watched, $timestamp;

        /**
         * Create a WatchedItem object with the given user and title
         * @since 1.22 $checkRights parameter added
         * @param $user User: the user to use for (un)watching
         * @param $title Title: the title we're going to (un)watch
         * @param $checkRights int: Whether to check the 'viewmywatchlist' and 'editmywatchlist' rights.
         *     Pass either WatchedItem::IGNORE_USER_RIGHTS or WatchedItem::CHECK_USER_RIGHTS.
         * @return WatchedItem object
         */
        public static function fromUserTitle( $user, $title, $checkRights = WatchedItem::CHECK_USER_RIGHTS ) {
                $wl = new WatchedItem;
                $wl->mUser = $user;
                $wl->mTitle = $title;
                $wl->mCheckRights = $checkRights;

                return $wl;
        }

        /**
         * Title being watched
         * @return Title
         */
        protected function getTitle() {
                return $this->mTitle;
        }

        /** Helper to retrieve the title namespace */
        protected function getTitleNs() {
                return $this->getTitle()->getNamespace();
        }

        /** Helper to retrieve the title DBkey */
        protected function getTitleDBkey() {
                return $this->getTitle()->getDBkey();
        }
        /** Helper to retrieve the user id */
        protected function getUserId() {
                return $this->mUser->getId();
        }

        /**
         * Return an array of conditions to select or update the appropriate database
         * row.
         *
         * @return array
         */
        private function dbCond() {
                return array(
                        'wl_user' => $this->getUserId(),
                        'wl_namespace' => $this->getTitleNs(),
                        'wl_title' => $this->getTitleDBkey(),
                );
        }

        /**
         * Load the object from the database
         */
        private function load() {
                if ( $this->loaded ) {
                        return;
                }
                $this->loaded = true;

                // Only loggedin user can have a watchlist
                if ( $this->mUser->isAnon() ) {
                        $this->watched = false;
                        return;
                }

                # Pages and their talk pages are considered equivalent for watching;
                # remember that talk namespaces are numbered as page namespace+1.

                $dbr = wfGetDB( DB_SLAVE );
                $row = $dbr->selectRow( 'watchlist', 'wl_notificationtimestamp',
                        $this->dbCond(), __METHOD__ );

                if ( $row === false ) {
                        $this->watched = false;
                } else {
                        $this->watched = true;
                        $this->timestamp = $row->wl_notificationtimestamp;
                }
        }

        /**
         * Check permissions
         * @param $what string: 'viewmywatchlist' or 'editmywatchlist'
         */
        private function isAllowed( $what ) {
                return !$this->mCheckRights || $this->mUser->isAllowed( $what );
        }

        /**
         * Is mTitle being watched by mUser?
         * @return bool
         */
        public function isWatched() {
                if ( !$this->isAllowed( 'viewmywatchlist' ) ) {
                        return false;
                }

                $this->load();
                return $this->watched;
        }

        /**
         * Get the notification timestamp of this entry.
         *
         * @return false|null|string: false if the page is not watched, the value of
         *         the wl_notificationtimestamp field otherwise
         */
        public function getNotificationTimestamp() {
                if ( !$this->isAllowed( 'viewmywatchlist' ) ) {
                        return false;
                }

                $this->load();
                if ( $this->watched ) {
                        return $this->timestamp;
                } else {
                        return false;
                }
        }

        /**
         * Reset the notification timestamp of this entry
         *
         * @param $force Whether to force the write query to be executed even if the
         *        page is not watched or the notification timestamp is already NULL.
         * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed.
         */
        public function resetNotificationTimestamp( $force = '', $oldid = 0 ) {
                // Only loggedin user can have a watchlist
                if ( wfReadOnly() || $this->mUser->isAnon() || !$this->isAllowed( 'editmywatchlist' ) ) {
                        return;
                }

                if ( $force != 'force' ) {
                        $this->load();
                        if ( !$this->watched || $this->timestamp === null ) {
                                return;
                        }
                }

                $title = $this->getTitle();
                if ( !$oldid ) {
                        // No oldid given, assuming latest revision; clear the timestamp.
                        $notificationTimestamp = null;
                } elseif ( !$title->getNextRevisionID( $oldid ) ) {
                        // Oldid given and is the latest revision for this title; clear the timestamp.
                        $notificationTimestamp = null;
                } else {
                        // See if the version marked as read is more recent than the one we're viewing.
                        // Call load() if it wasn't called before due to $force.
                        $this->load();

                        if ( $this->timestamp === null ) {
                                // This can only happen if $force is enabled.
                                $notificationTimestamp = null;
                        } else {
                                // Oldid given and isn't the latest; update the timestamp.
                                // This will result in no further notification emails being sent!
                                $dbr = wfGetDB( DB_SLAVE );
                                $notificationTimestamp = $dbr->selectField(
                                        'revision', 'rev_timestamp',
                                        array( 'rev_page' => $title->getArticleID(), 'rev_id' => $oldid )
                                );
                                // We need to go one second to the future because of various strict comparisons
                                // throughout the codebase
                                $ts = new MWTimestamp( $notificationTimestamp );
                                $ts->timestamp->add( new DateInterval( 'PT1S' ) );
                                $notificationTimestamp = $ts->getTimestamp( TS_MW );

                                if ( $notificationTimestamp < $this->timestamp ) {
                                        if ( $force != 'force' ) {
                                                return;
                                        } else {
                                                // This is a little silly…
                                                $notificationTimestamp = $this->timestamp;
                                        }
                                }
                        }
                }

                // If the page is watched by the user (or may be watched), update the timestamp on any
                // any matching rows
                $dbw = wfGetDB( DB_MASTER );
                $dbw->update( 'watchlist', array( 'wl_notificationtimestamp' => $notificationTimestamp ),
                        $this->dbCond(), __METHOD__ );
                $this->timestamp = null;
        }

        /**
         * Given a title and user (assumes the object is setup), add the watch to the
         * database.
         * @return bool
         */
        public function addWatch() {
                wfProfileIn( __METHOD__ );

                // Only loggedin user can have a watchlist
                if ( wfReadOnly() || $this->mUser->isAnon() || !$this->isAllowed( 'editmywatchlist' ) ) {
                        wfProfileOut( __METHOD__ );
                        return false;
                }

                // Use INSERT IGNORE to avoid overwriting the notification timestamp
                // if there's already an entry for this page
                $dbw = wfGetDB( DB_MASTER );
                $dbw->insert( 'watchlist',
                        array(
                                'wl_user' => $this->getUserId(),
                                'wl_namespace' => MWNamespace::getSubject( $this->getTitleNs() ),
                                'wl_title' => $this->getTitleDBkey(),
                                'wl_notificationtimestamp' => null
                        ), __METHOD__, 'IGNORE' );

                // Every single watched page needs now to be listed in watchlist;
                // namespace:page and namespace_talk:page need separate entries:
                $dbw->insert( 'watchlist',
                        array(
                                'wl_user' => $this->getUserId(),
                                'wl_namespace' => MWNamespace::getTalk( $this->getTitleNs() ),
                                'wl_title' => $this->getTitleDBkey(),
                                'wl_notificationtimestamp' => null
                        ), __METHOD__, 'IGNORE' );

                $this->watched = true;

                wfProfileOut( __METHOD__ );
                return true;
        }

        /**
         * Same as addWatch, only the opposite.
         * @return bool
         */
        public function removeWatch() {
                wfProfileIn( __METHOD__ );

                // Only loggedin user can have a watchlist
                if ( wfReadOnly() || $this->mUser->isAnon() || !$this->isAllowed( 'editmywatchlist' ) ) {
                        wfProfileOut( __METHOD__ );
                        return false;
                }

                $success = false;
                $dbw = wfGetDB( DB_MASTER );
                $dbw->delete( 'watchlist',
                        array(
                                'wl_user' => $this->getUserId(),
                                'wl_namespace' => MWNamespace::getSubject( $this->getTitleNs() ),
                                'wl_title' => $this->getTitleDBkey(),
                        ), __METHOD__
                );
                if ( $dbw->affectedRows() ) {
                        $success = true;
                }

                # the following code compensates the new behavior, introduced by the
                # enotif patch, that every single watched page needs now to be listed
                # in watchlist namespace:page and namespace_talk:page had separate
                # entries: clear them
                $dbw->delete( 'watchlist',
                        array(
                                'wl_user' => $this->getUserId(),
                                'wl_namespace' => MWNamespace::getTalk( $this->getTitleNs() ),
                                'wl_title' => $this->getTitleDBkey(),
                        ), __METHOD__
                );

                if ( $dbw->affectedRows() ) {
                        $success = true;
                }

                $this->watched = false;

                wfProfileOut( __METHOD__ );
                return $success;
        }

        /**
         * Check if the given title already is watched by the user, and if so
         * add watches on a new title. To be used for page renames and such.
         *
         * @param $ot Title: page title to duplicate entries from, if present
         * @param $nt Title: page title to add watches on
         */
        public static function duplicateEntries( $ot, $nt ) {
                WatchedItem::doDuplicateEntries( $ot->getSubjectPage(), $nt->getSubjectPage() );
                WatchedItem::doDuplicateEntries( $ot->getTalkPage(), $nt->getTalkPage() );
        }

        /**
         * Handle duplicate entries. Backend for duplicateEntries().
         *
         * @param $ot Title
         * @param $nt Title
         *
         * @return bool
         */
        private static function doDuplicateEntries( $ot, $nt ) {
                $oldnamespace = $ot->getNamespace();
                $newnamespace = $nt->getNamespace();
                $oldtitle = $ot->getDBkey();
                $newtitle = $nt->getDBkey();

                $dbw = wfGetDB( DB_MASTER );
                $res = $dbw->select( 'watchlist', 'wl_user',
                        array( 'wl_namespace' => $oldnamespace, 'wl_title' => $oldtitle ),
                        __METHOD__, 'FOR UPDATE'
                );
                # Construct array to replace into the watchlist
                $values = array();
                foreach ( $res as $s ) {
                        $values[] = array(
                                'wl_user' => $s->wl_user,
                                'wl_namespace' => $newnamespace,
                                'wl_title' => $newtitle
                        );
                }

                if ( empty( $values ) ) {
                        // Nothing to do
                        return true;
                }

                # Perform replace
                # Note that multi-row replace is very efficient for MySQL but may be inefficient for
                # some other DBMSes, mostly due to poor simulation by us
                $dbw->replace( 'watchlist', array( array( 'wl_user', 'wl_namespace', 'wl_title' ) ), $values, __METHOD__ );
                return true;
        }
}