ImageHistoryPseudoPager.php

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<?php
use Wikimedia\Timestamp\TimestampException;

class ImageHistoryPseudoPager extends ReverseChronologicalPager {
    protected $preventClickjacking = false;

    protected $mImg;

    protected $mTitle;

    public $mImagePage;

    public $mHist;

    public $mRange;

    public function __construct( $imagePage ) {
        parent::__construct( $imagePage->getContext() );
        $this->mImagePage = $imagePage;
        $this->mTitle = $imagePage->getTitle()->createFragmentTarget( '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, '' );
    }

    public function getTitle() {
        return $this->mTitle;
    }

    public function getQueryInfo() {
        return false;
    }

    public function getIndexField() {
        return '';
    }

    public function formatRow( $row ) {
        return '';
    }

    public 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;
    }

    public function doQuery() {
        if ( $this->mQueryDone ) {
            return;
        }
        $this->mImg = $this->mImagePage->getPage()->getFile(); // ensure loading
        if ( !$this->mImg->exists() ) {
            return;
        }
        // Make sure the date (probably from user input) is valid; if not, drop it.
        if ( $this->mOffset !== null ) {
            try {
                $sadlyWeCannotPassThisTimestampDownTheStack = $this->mDb->timestamp( $this->mOffset );
            } catch ( TimestampException $e ) {
                $this->mOffset = null;
            }
        }
        $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;
    }

    protected function preventClickjacking( $enable = true ) {
        $this->preventClickjacking = $enable;
    }

    public function getPreventClickjacking() {
        return $this->preventClickjacking;
    }

}