populateRevisionSha1.php

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<?php
require_once __DIR__ . '/Maintenance.php';

class PopulateRevisionSha1 extends LoggedUpdateMaintenance {
    public function __construct() {
        parent::__construct();
        $this->mDescription = "Populates the rev_sha1 and ar_sha1 fields";
        $this->setBatchSize( 200 );
    }

    protected function getUpdateKey() {
        return 'populate rev_sha1';
    }

    protected function doDBUpdates() {
        $db = $this->getDB( DB_MASTER );

        if ( !$db->tableExists( 'revision' ) ) {
            $this->error( "revision table does not exist", true );
        } elseif ( !$db->tableExists( 'archive' ) ) {
            $this->error( "archive table does not exist", true );
        } elseif ( !$db->fieldExists( 'revision', 'rev_sha1', __METHOD__ ) ) {
            $this->output( "rev_sha1 column does not exist\n\n", true );

            return false;
        }

        $this->output( "Populating rev_sha1 column\n" );
        $rc = $this->doSha1Updates( 'revision', 'rev_id', 'rev' );

        $this->output( "Populating ar_sha1 column\n" );
        $ac = $this->doSha1Updates( 'archive', 'ar_rev_id', 'ar' );
        $this->output( "Populating ar_sha1 column legacy rows\n" );
        $ac += $this->doSha1LegacyUpdates();

        $this->output( "rev_sha1 and ar_sha1 population complete "
            . "[$rc revision rows, $ac archive rows].\n" );

        return true;
    }

    protected function doSha1Updates( $table, $idCol, $prefix ) {
        $db = $this->getDB( DB_MASTER );
        $start = $db->selectField( $table, "MIN($idCol)", false, __METHOD__ );
        $end = $db->selectField( $table, "MAX($idCol)", false, __METHOD__ );
        if ( !$start || !$end ) {
            $this->output( "...$table table seems to be empty.\n" );

            return 0;
        }

        $count = 0;
        # Do remaining chunk
        $end += $this->mBatchSize - 1;
        $blockStart = $start;
        $blockEnd = $start + $this->mBatchSize - 1;
        while ( $blockEnd <= $end ) {
            $this->output( "...doing $idCol from $blockStart to $blockEnd\n" );
            $cond = "$idCol BETWEEN $blockStart AND $blockEnd
                AND $idCol IS NOT NULL AND {$prefix}_sha1 = ''";
            $res = $db->select( $table, '*', $cond, __METHOD__ );

            $db->begin( __METHOD__ );
            foreach ( $res as $row ) {
                if ( $this->upgradeRow( $row, $table, $idCol, $prefix ) ) {
                    $count++;
                }
            }
            $db->commit( __METHOD__ );

            $blockStart += $this->mBatchSize;
            $blockEnd += $this->mBatchSize;
            wfWaitForSlaves();
        }

        return $count;
    }

    protected function doSha1LegacyUpdates() {
        $count = 0;
        $db = $this->getDB( DB_MASTER );
        $res = $db->select( 'archive', '*',
            array( 'ar_rev_id IS NULL', 'ar_sha1' => '' ), __METHOD__ );

        $updateSize = 0;
        $db->begin( __METHOD__ );
        foreach ( $res as $row ) {
            if ( $this->upgradeLegacyArchiveRow( $row ) ) {
                ++$count;
            }
            if ( ++$updateSize >= 100 ) {
                $updateSize = 0;
                $db->commit( __METHOD__ );
                $this->output( "Commited row with ar_timestamp={$row->ar_timestamp}\n" );
                wfWaitForSlaves();
                $db->begin( __METHOD__ );
            }
        }
        $db->commit( __METHOD__ );

        return $count;
    }

    protected function upgradeRow( $row, $table, $idCol, $prefix ) {
        $db = $this->getDB( DB_MASTER );
        try {
            $rev = ( $table === 'archive' )
                ? Revision::newFromArchiveRow( $row )
                : new Revision( $row );
            $text = $rev->getSerializedData();
        } catch ( MWException $e ) {
            $this->output( "Data of revision with {$idCol}={$row->$idCol} unavailable!\n" );

            return false; // bug 22624?
        }
        if ( !is_string( $text ) ) {
            # This should not happen, but sometimes does (bug 20757)
            $this->output( "Data of revision with {$idCol}={$row->$idCol} unavailable!\n" );

            return false;
        } else {
            $db->update( $table,
                array( "{$prefix}_sha1" => Revision::base36Sha1( $text ) ),
                array( $idCol => $row->$idCol ),
                __METHOD__
            );

            return true;
        }
    }

    protected function upgradeLegacyArchiveRow( $row ) {
        $db = $this->getDB( DB_MASTER );
        try {
            $rev = Revision::newFromArchiveRow( $row );
        } catch ( MWException $e ) {
            $this->output( "Text of revision with timestamp {$row->ar_timestamp} unavailable!\n" );

            return false; // bug 22624?
        }
        $text = $rev->getSerializedData();
        if ( !is_string( $text ) ) {
            # This should not happen, but sometimes does (bug 20757)
            $this->output( "Data of revision with timestamp {$row->ar_timestamp} unavailable!\n" );

            return false;
        } else {
            # Archive table as no PK, but (NS,title,time) should be near unique.
            # Any duplicates on those should also have duplicated text anyway.
            $db->update( 'archive',
                array( 'ar_sha1' => Revision::base36Sha1( $text ) ),
                array(
                    'ar_namespace' => $row->ar_namespace,
                    'ar_title' => $row->ar_title,
                    'ar_timestamp' => $row->ar_timestamp,
                    'ar_len' => $row->ar_len // extra sanity
                ),
                __METHOD__
            );

            return true;
        }
    }
}

$maintClass = "PopulateRevisionSha1";
require_once RUN_MAINTENANCE_IF_MAIN;