Move remaining LoadBalancer classes to Rdbms

[mediawiki.git] / includes / page / ImageHistoryPseudoPager.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
 */

class ImageHistoryPseudoPager extends ReverseChronologicalPager {
        protected $preventClickjacking = false;

        /**
         * @var File
         */
        protected $mImg;

        /**
         * @var Title
         */
        protected $mTitle;

        /**
         * @param ImagePage $imagePage
         */
        function __construct( $imagePage ) {
                parent::__construct( $imagePage->getContext() );
                $this->mImagePage = $imagePage;
                $this->mTitle = clone $imagePage->getTitle();
                $this->mTitle->setFragment( '#filehistory' );
                $this->mImg = null;
                $this->mHist = [];
                $this->mRange = [ 0, 0 ]; // display range

                // Only display 10 revisions at once by default, otherwise the list is overwhelming
                $this->mLimitsShown = array_merge( [ 10 ], $this->mLimitsShown );
                $this->mDefaultLimit = 10;
                list( $this->mLimit, /* $offset */ ) =
                        $this->mRequest->getLimitOffset( $this->mDefaultLimit, '' );
        }

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

        function getQueryInfo() {
                return false;
        }

        /**
         * @return string
         */
        function getIndexField() {
                return '';
        }

        /**
         * @param object $row
         * @return string
         */
        function formatRow( $row ) {
                return '';
        }

        /**
         * @return string
         */
        function getBody() {
                $s = '';
                $this->doQuery();
                if ( count( $this->mHist ) ) {
                        if ( $this->mImg->isLocal() ) {
                                // Do a batch existence check for user pages and talkpages
                                $linkBatch = new LinkBatch();
                                for ( $i = $this->mRange[0]; $i <= $this->mRange[1]; $i++ ) {
                                        $file = $this->mHist[$i];
                                        $user = $file->getUser( 'text' );
                                        $linkBatch->add( NS_USER, $user );
                                        $linkBatch->add( NS_USER_TALK, $user );
                                }
                                $linkBatch->execute();
                        }

                        $list = new ImageHistoryList( $this->mImagePage );
                        # Generate prev/next links
                        $navLink = $this->getNavigationBar();
                        $s = $list->beginImageHistoryList( $navLink );
                        // Skip rows there just for paging links
                        for ( $i = $this->mRange[0]; $i <= $this->mRange[1]; $i++ ) {
                                $file = $this->mHist[$i];
                                $s .= $list->imageHistoryLine( !$file->isOld(), $file );
                        }
                        $s .= $list->endImageHistoryList( $navLink );

                        if ( $list->getPreventClickjacking() ) {
                                $this->preventClickjacking();
                        }
                }
                return $s;
        }

        function doQuery() {
                if ( $this->mQueryDone ) {
                        return;
                }
                $this->mImg = $this->mImagePage->getPage()->getFile(); // ensure loading
                if ( !$this->mImg->exists() ) {
                        return;
                }
                $queryLimit = $this->mLimit + 1; // limit plus extra row
                if ( $this->mIsBackwards ) {
                        // Fetch the file history
                        $this->mHist = $this->mImg->getHistory( $queryLimit, null, $this->mOffset, false );
                        // The current rev may not meet the offset/limit
                        $numRows = count( $this->mHist );
                        if ( $numRows <= $this->mLimit && $this->mImg->getTimestamp() > $this->mOffset ) {
                                $this->mHist = array_merge( [ $this->mImg ], $this->mHist );
                        }
                } else {
                        // The current rev may not meet the offset
                        if ( !$this->mOffset || $this->mImg->getTimestamp() < $this->mOffset ) {
                                $this->mHist[] = $this->mImg;
                        }
                        // Old image versions (fetch extra row for nav links)
                        $oiLimit = count( $this->mHist ) ? $this->mLimit : $this->mLimit + 1;
                        // Fetch the file history
                        $this->mHist = array_merge( $this->mHist,
                                $this->mImg->getHistory( $oiLimit, $this->mOffset, null, false ) );
                }
                $numRows = count( $this->mHist ); // Total number of query results
                if ( $numRows ) {
                        # Index value of top item in the list
                        $firstIndex = $this->mIsBackwards ?
                                $this->mHist[$numRows - 1]->getTimestamp() : $this->mHist[0]->getTimestamp();
                        # Discard the extra result row if there is one
                        if ( $numRows > $this->mLimit && $numRows > 1 ) {
                                if ( $this->mIsBackwards ) {
                                        # Index value of item past the index
                                        $this->mPastTheEndIndex = $this->mHist[0]->getTimestamp();
                                        # Index value of bottom item in the list
                                        $lastIndex = $this->mHist[1]->getTimestamp();
                                        # Display range
                                        $this->mRange = [ 1, $numRows - 1 ];
                                } else {
                                        # Index value of item past the index
                                        $this->mPastTheEndIndex = $this->mHist[$numRows - 1]->getTimestamp();
                                        # Index value of bottom item in the list
                                        $lastIndex = $this->mHist[$numRows - 2]->getTimestamp();
                                        # Display range
                                        $this->mRange = [ 0, $numRows - 2 ];
                                }
                        } else {
                                # Setting indexes to an empty string means that they will be
                                # omitted if they would otherwise appear in URLs. It just so
                                # happens that this  is the right thing to do in the standard
                                # UI, in all the relevant cases.
                                $this->mPastTheEndIndex = '';
                                # Index value of bottom item in the list
                                $lastIndex = $this->mIsBackwards ?
                                        $this->mHist[0]->getTimestamp() : $this->mHist[$numRows - 1]->getTimestamp();
                                # Display range
                                $this->mRange = [ 0, $numRows - 1 ];
                        }
                } else {
                        $firstIndex = '';
                        $lastIndex = '';
                        $this->mPastTheEndIndex = '';
                }
                if ( $this->mIsBackwards ) {
                        $this->mIsFirst = ( $numRows < $queryLimit );
                        $this->mIsLast = ( $this->mOffset == '' );
                        $this->mLastShown = $firstIndex;
                        $this->mFirstShown = $lastIndex;
                } else {
                        $this->mIsFirst = ( $this->mOffset == '' );
                        $this->mIsLast = ( $numRows < $queryLimit );
                        $this->mLastShown = $lastIndex;
                        $this->mFirstShown = $firstIndex;
                }
                $this->mQueryDone = true;
        }

        /**
         * @param bool $enable
         */
        protected function preventClickjacking( $enable = true ) {
                $this->preventClickjacking = $enable;
        }

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

}