PageArchive.php

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<?php
use MediaWiki\MediaWikiServices;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionStore;
use Wikimedia\Assert\Assert;
use Wikimedia\Rdbms\IResultWrapper;
use Wikimedia\Rdbms\IDatabase;

class PageArchive {
    protected $title;

    protected $fileStatus;

    protected $revisionStatus;

    protected $config;

    public function __construct( $title, Config $config = null ) {
        if ( is_null( $title ) ) {
            throw new MWException( __METHOD__ . ' given a null title.' );
        }
        $this->title = $title;
        if ( $config === null ) {
            wfDebug( __METHOD__ . ' did not have a Config object passed to it' );
            $config = MediaWikiServices::getInstance()->getMainConfig();
        }
        $this->config = $config;
    }

    private function getRevisionStore() {
        // TODO: Refactor: delete()/undelete() should live in a PageStore service;
        //       Methods in PageArchive and RevisionStore that deal with archive revisions
        //       should move into an ArchiveStore service (but could still be implemented
        //       together with RevisionStore).
        return MediaWikiServices::getInstance()->getRevisionStore();
    }

    public function doesWrites() {
        return true;
    }

    public static function listPagesBySearch( $term ) {
        $title = Title::newFromText( $term );
        if ( $title ) {
            $ns = $title->getNamespace();
            $termMain = $title->getText();
            $termDb = $title->getDBkey();
        } else {
            // Prolly won't work too good
            // @todo handle bare namespace names cleanly?
            $ns = 0;
            $termMain = $termDb = $term;
        }

        // Try search engine first
        $engine = MediaWikiServices::getInstance()->newSearchEngine();
        $engine->setLimitOffset( 100 );
        $engine->setNamespaces( [ $ns ] );
        $results = $engine->searchArchiveTitle( $termMain );
        if ( !$results->isOK() ) {
            $results = [];
        } else {
            $results = $results->getValue();
        }

        if ( !$results ) {
            // Fall back to regular prefix search
            return self::listPagesByPrefix( $term );
        }

        $dbr = wfGetDB( DB_REPLICA );
        $condTitles = array_unique( array_map( function ( Title $t ) {
            return $t->getDBkey();
        }, $results ) );
        $conds = [
            'ar_namespace' => $ns,
            $dbr->makeList( [ 'ar_title' => $condTitles ], LIST_OR ) . " OR ar_title " .
            $dbr->buildLike( $termDb, $dbr->anyString() )
        ];

        return self::listPages( $dbr, $conds );
    }

    public static function listPagesByPrefix( $prefix ) {
        $dbr = wfGetDB( DB_REPLICA );

        $title = Title::newFromText( $prefix );
        if ( $title ) {
            $ns = $title->getNamespace();
            $prefix = $title->getDBkey();
        } else {
            // Prolly won't work too good
            // @todo handle bare namespace names cleanly?
            $ns = 0;
        }

        $conds = [
            'ar_namespace' => $ns,
            'ar_title' . $dbr->buildLike( $prefix, $dbr->anyString() ),
        ];

        return self::listPages( $dbr, $conds );
    }

    protected static function listPages( $dbr, $condition ) {
        return $dbr->select(
            [ 'archive' ],
            [
                'ar_namespace',
                'ar_title',
                'count' => 'COUNT(*)'
            ],
            $condition,
            __METHOD__,
            [
                'GROUP BY' => [ 'ar_namespace', 'ar_title' ],
                'ORDER BY' => [ 'ar_namespace', 'ar_title' ],
                'LIMIT' => 100,
            ]
        );
    }

    public function listRevisions() {
        $revisionStore = $this->getRevisionStore();
        $queryInfo = $revisionStore->getArchiveQueryInfo();

        $conds = [
            'ar_namespace' => $this->title->getNamespace(),
            'ar_title' => $this->title->getDBkey(),
        ];

        // NOTE: ordering by ar_timestamp and ar_id, to remove ambiguity.
        // XXX: Ideally, we would be ordering by ar_timestamp and ar_rev_id, but since we
        // don't have an index on ar_rev_id, that causes a file sort.
        $options = [ 'ORDER BY' => 'ar_timestamp DESC, ar_id DESC' ];

        ChangeTags::modifyDisplayQuery(
            $queryInfo['tables'],
            $queryInfo['fields'],
            $conds,
            $queryInfo['joins'],
            $options,
            ''
        );

        $dbr = wfGetDB( DB_REPLICA );
        return $dbr->select(
            $queryInfo['tables'],
            $queryInfo['fields'],
            $conds,
            __METHOD__,
            $options,
            $queryInfo['joins']
        );
    }

    public function listFiles() {
        if ( $this->title->getNamespace() != NS_FILE ) {
            return null;
        }

        $dbr = wfGetDB( DB_REPLICA );
        $fileQuery = ArchivedFile::getQueryInfo();
        return $dbr->select(
            $fileQuery['tables'],
            $fileQuery['fields'],
            [ 'fa_name' => $this->title->getDBkey() ],
            __METHOD__,
            [ 'ORDER BY' => 'fa_timestamp DESC' ],
            $fileQuery['joins']
        );
    }

    public function getRevision( $timestamp ) {
        $dbr = wfGetDB( DB_REPLICA );
        $rec = $this->getRevisionByConditions(
            [ 'ar_timestamp' => $dbr->timestamp( $timestamp ) ]
        );
        return $rec ? new Revision( $rec ) : null;
    }

    public function getArchivedRevision( $revId ) {
        // Protect against code switching from getRevision() passing in a timestamp.
        Assert::parameterType( 'integer', $revId, '$revId' );

        $rec = $this->getRevisionByConditions( [ 'ar_rev_id' => $revId ] );
        return $rec ? new Revision( $rec ) : null;
    }

    private function getRevisionByConditions( array $conditions, array $options = [] ) {
        $dbr = wfGetDB( DB_REPLICA );
        $arQuery = $this->getRevisionStore()->getArchiveQueryInfo();

        $conditions = $conditions + [
            'ar_namespace' => $this->title->getNamespace(),
            'ar_title' => $this->title->getDBkey(),
        ];

        $row = $dbr->selectRow(
            $arQuery['tables'],
            $arQuery['fields'],
            $conditions,
            __METHOD__,
            $options,
            $arQuery['joins']
        );

        if ( $row ) {
            return $this->getRevisionStore()->newRevisionFromArchiveRow( $row, 0, $this->title );
        }

        return null;
    }

    public function getPreviousRevision( $timestamp ) {
        $dbr = wfGetDB( DB_REPLICA );

        // Check the previous deleted revision...
        $row = $dbr->selectRow( 'archive',
            [ 'ar_rev_id', 'ar_timestamp' ],
            [ 'ar_namespace' => $this->title->getNamespace(),
                'ar_title' => $this->title->getDBkey(),
                'ar_timestamp < ' .
                $dbr->addQuotes( $dbr->timestamp( $timestamp ) ) ],
            __METHOD__,
            [
                'ORDER BY' => 'ar_timestamp DESC',
                'LIMIT' => 1 ] );
        $prevDeleted = $row ? wfTimestamp( TS_MW, $row->ar_timestamp ) : false;
        $prevDeletedId = $row ? intval( $row->ar_rev_id ) : null;

        $row = $dbr->selectRow( [ 'page', 'revision' ],
            [ 'rev_id', 'rev_timestamp' ],
            [
                'page_namespace' => $this->title->getNamespace(),
                'page_title' => $this->title->getDBkey(),
                'page_id = rev_page',
                'rev_timestamp < ' .
                $dbr->addQuotes( $dbr->timestamp( $timestamp ) ) ],
            __METHOD__,
            [
                'ORDER BY' => 'rev_timestamp DESC',
                'LIMIT' => 1 ] );
        $prevLive = $row ? wfTimestamp( TS_MW, $row->rev_timestamp ) : false;
        $prevLiveId = $row ? intval( $row->rev_id ) : null;

        if ( $prevLive && $prevLive > $prevDeleted ) {
            // Most prior revision was live
            $rec = $this->getRevisionStore()->getRevisionById( $prevLiveId );
            $rec = $rec ? new Revision( $rec ) : null;
        } elseif ( $prevDeleted ) {
            // Most prior revision was deleted
            $rec = $this->getArchivedRevision( $prevDeletedId );
        } else {
            $rec = null;
        }

        return $rec;
    }

    public function getLastRevisionId() {
        $dbr = wfGetDB( DB_REPLICA );
        $revId = $dbr->selectField(
            'archive',
            'ar_rev_id',
            [ 'ar_namespace' => $this->title->getNamespace(),
                'ar_title' => $this->title->getDBkey() ],
            __METHOD__,
            [ 'ORDER BY' => 'ar_timestamp DESC, ar_id DESC' ]
        );

        return $revId ? intval( $revId ) : false;
    }

    public function isDeleted() {
        $dbr = wfGetDB( DB_REPLICA );
        $row = $dbr->selectRow(
            [ 'archive' ],
            '1', // We don't care about the value. Allow the database to optimize.
            [ 'ar_namespace' => $this->title->getNamespace(),
                'ar_title' => $this->title->getDBkey() ],
            __METHOD__
        );

        return (bool)$row;
    }

    public function undelete( $timestamps, $comment = '', $fileVersions = [],
        $unsuppress = false, User $user = null, $tags = null
    ) {
        // If both the set of text revisions and file revisions are empty,
        // restore everything. Otherwise, just restore the requested items.
        $restoreAll = empty( $timestamps ) && empty( $fileVersions );

        $restoreText = $restoreAll || !empty( $timestamps );
        $restoreFiles = $restoreAll || !empty( $fileVersions );

        if ( $restoreFiles && $this->title->getNamespace() == NS_FILE ) {
            $img = MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo()
                ->newFile( $this->title );
            $img->load( File::READ_LATEST );
            $this->fileStatus = $img->restore( $fileVersions, $unsuppress );
            if ( !$this->fileStatus->isOK() ) {
                return false;
            }
            $filesRestored = $this->fileStatus->successCount;
        } else {
            $filesRestored = 0;
        }

        if ( $restoreText ) {
            $this->revisionStatus = $this->undeleteRevisions( $timestamps, $unsuppress, $comment );
            if ( !$this->revisionStatus->isOK() ) {
                return false;
            }

            $textRestored = $this->revisionStatus->getValue();
        } else {
            $textRestored = 0;
        }

        // Touch the log!

        if ( !$textRestored && !$filesRestored ) {
            wfDebug( "Undelete: nothing undeleted...\n" );

            return false;
        }

        if ( $user === null ) {
            global $wgUser;
            $user = $wgUser;
        }

        $logEntry = new ManualLogEntry( 'delete', 'restore' );
        $logEntry->setPerformer( $user );
        $logEntry->setTarget( $this->title );
        $logEntry->setComment( $comment );
        $logEntry->setTags( $tags );
        $logEntry->setParameters( [
            ':assoc:count' => [
                'revisions' => $textRestored,
                'files' => $filesRestored,
            ],
        ] );

        Hooks::run( 'ArticleUndeleteLogEntry', [ $this, &$logEntry, $user ] );

        $logid = $logEntry->insert();
        $logEntry->publish( $logid );

        return [ $textRestored, $filesRestored, $comment ];
    }

    private function undeleteRevisions( $timestamps, $unsuppress = false, $comment = '' ) {
        if ( wfReadOnly() ) {
            throw new ReadOnlyError();
        }

        $dbw = wfGetDB( DB_MASTER );
        $dbw->startAtomic( __METHOD__ );

        $restoreAll = empty( $timestamps );

        # Does this page already exist? We'll have to update it...
        $article = WikiPage::factory( $this->title );
        # Load latest data for the current page (T33179)
        $article->loadPageData( 'fromdbmaster' );
        $oldcountable = $article->isCountable();

        $page = $dbw->selectRow( 'page',
            [ 'page_id', 'page_latest' ],
            [ 'page_namespace' => $this->title->getNamespace(),
                'page_title' => $this->title->getDBkey() ],
            __METHOD__,
            [ 'FOR UPDATE' ] // lock page
        );

        if ( $page ) {
            $makepage = false;
            # Page already exists. Import the history, and if necessary
            # we'll update the latest revision field in the record.

            # Get the time span of this page
            $previousTimestamp = $dbw->selectField( 'revision', 'rev_timestamp',
                [ 'rev_id' => $page->page_latest ],
                __METHOD__ );

            if ( $previousTimestamp === false ) {
                wfDebug( __METHOD__ . ": existing page refers to a page_latest that does not exist\n" );

                $status = Status::newGood( 0 );
                $status->warning( 'undeleterevision-missing' );
                $dbw->endAtomic( __METHOD__ );

                return $status;
            }
        } else {
            # Have to create a new article...
            $makepage = true;
            $previousTimestamp = 0;
        }

        $oldWhere = [
            'ar_namespace' => $this->title->getNamespace(),
            'ar_title' => $this->title->getDBkey(),
        ];
        if ( !$restoreAll ) {
            $oldWhere['ar_timestamp'] = array_map( [ &$dbw, 'timestamp' ], $timestamps );
        }

        $revisionStore = $this->getRevisionStore();
        $queryInfo = $revisionStore->getArchiveQueryInfo();
        $queryInfo['tables'][] = 'revision';
        $queryInfo['fields'][] = 'rev_id';
        $queryInfo['joins']['revision'] = [ 'LEFT JOIN', 'ar_rev_id=rev_id' ];

        $result = $dbw->select(
            $queryInfo['tables'],
            $queryInfo['fields'],
            $oldWhere,
            __METHOD__,
            /* options */
            [ 'ORDER BY' => 'ar_timestamp' ],
            $queryInfo['joins']
        );

        $rev_count = $result->numRows();
        if ( !$rev_count ) {
            wfDebug( __METHOD__ . ": no revisions to restore\n" );

            $status = Status::newGood( 0 );
            $status->warning( "undelete-no-results" );
            $dbw->endAtomic( __METHOD__ );

            return $status;
        }

        // We use ar_id because there can be duplicate ar_rev_id even for the same
        // page.  In this case, we may be able to restore the first one.
        $restoreFailedArIds = [];

        // Map rev_id to the ar_id that is allowed to use it.  When checking later,
        // if it doesn't match, the current ar_id can not be restored.

        // Value can be an ar_id or -1 (-1 means no ar_id can use it, since the
        // rev_id is taken before we even start the restore).
        $allowedRevIdToArIdMap = [];

        $latestRestorableRow = null;

        foreach ( $result as $row ) {
            if ( $row->ar_rev_id ) {
                // rev_id is taken even before we start restoring.
                if ( $row->ar_rev_id === $row->rev_id ) {
                    $restoreFailedArIds[] = $row->ar_id;
                    $allowedRevIdToArIdMap[$row->ar_rev_id] = -1;
                } else {
                    // rev_id is not taken yet in the DB, but it might be taken
                    // by a prior revision in the same restore operation. If
                    // not, we need to reserve it.
                    if ( isset( $allowedRevIdToArIdMap[$row->ar_rev_id] ) ) {
                        $restoreFailedArIds[] = $row->ar_id;
                    } else {
                        $allowedRevIdToArIdMap[$row->ar_rev_id] = $row->ar_id;
                        $latestRestorableRow = $row;
                    }
                }
            } else {
                // If ar_rev_id is null, there can't be a collision, and a
                // rev_id will be chosen automatically.
                $latestRestorableRow = $row;
            }
        }

        $result->seek( 0 ); // move back

        $oldPageId = 0;
        if ( $latestRestorableRow !== null ) {
            $oldPageId = (int)$latestRestorableRow->ar_page_id; // pass this to ArticleUndelete hook

            // Grab the content to check consistency with global state before restoring the page.
            // XXX: The only current use case is Wikibase, which tries to enforce uniqueness of
            // certain things across all pages. There may be a better way to do that.
            $revision = $revisionStore->newRevisionFromArchiveRow(
                $latestRestorableRow,
                0,
                $this->title
            );

            // TODO: use User::newFromUserIdentity from If610c68f4912e
            // TODO: The User isn't used for anything in prepareSave()! We should drop it.
            $user = User::newFromName( $revision->getUser( RevisionRecord::RAW )->getName(), false );

            foreach ( $revision->getSlotRoles() as $role ) {
                $content = $revision->getContent( $role, RevisionRecord::RAW );

                // NOTE: article ID may not be known yet. prepareSave() should not modify the database.
                $status = $content->prepareSave( $article, 0, -1, $user );
                if ( !$status->isOK() ) {
                    $dbw->endAtomic( __METHOD__ );

                    return $status;
                }
            }
        }

        $newid = false; // newly created page ID
        $restored = 0; // number of revisions restored
        $revision = null;
        $restoredPages = [];
        // If there are no restorable revisions, we can skip most of the steps.
        if ( $latestRestorableRow === null ) {
            $failedRevisionCount = $rev_count;
        } else {
            if ( $makepage ) {
                // Check the state of the newest to-be version...
                if ( !$unsuppress
                    && ( $latestRestorableRow->ar_deleted & RevisionRecord::DELETED_TEXT )
                ) {
                    $dbw->endAtomic( __METHOD__ );

                    return Status::newFatal( "undeleterevdel" );
                }
                // Safe to insert now...
                $newid = $article->insertOn( $dbw, $latestRestorableRow->ar_page_id );
                if ( $newid === false ) {
                    // The old ID is reserved; let's pick another
                    $newid = $article->insertOn( $dbw );
                }
                $pageId = $newid;
            } else {
                // Check if a deleted revision will become the current revision...
                if ( $latestRestorableRow->ar_timestamp > $previousTimestamp ) {
                    // Check the state of the newest to-be version...
                    if ( !$unsuppress
                        && ( $latestRestorableRow->ar_deleted & RevisionRecord::DELETED_TEXT )
                    ) {
                        $dbw->endAtomic( __METHOD__ );

                        return Status::newFatal( "undeleterevdel" );
                    }
                }

                $newid = false;
                $pageId = $article->getId();
            }

            foreach ( $result as $row ) {
                // Check for key dupes due to needed archive integrity.
                if ( $row->ar_rev_id && $allowedRevIdToArIdMap[$row->ar_rev_id] !== $row->ar_id ) {
                    continue;
                }
                // Insert one revision at a time...maintaining deletion status
                // unless we are specifically removing all restrictions...
                $revision = $revisionStore->newRevisionFromArchiveRow(
                    $row,
                    0,
                    $this->title,
                    [
                        'page_id' => $pageId,
                        'deleted' => $unsuppress ? 0 : $row->ar_deleted
                    ]
                );

                // This will also copy the revision to ip_changes if it was an IP edit.
                $revisionStore->insertRevisionOn( $revision, $dbw );

                $restored++;

                $legacyRevision = new Revision( $revision );
                Hooks::run( 'ArticleRevisionUndeleted',
                    [ &$this->title, $legacyRevision, $row->ar_page_id ] );
                $restoredPages[$row->ar_page_id] = true;
            }

            // Now that it's safely stored, take it out of the archive
            // Don't delete rows that we failed to restore
            $toDeleteConds = $oldWhere;
            $failedRevisionCount = count( $restoreFailedArIds );
            if ( $failedRevisionCount > 0 ) {
                $toDeleteConds[] = 'ar_id NOT IN ( ' . $dbw->makeList( $restoreFailedArIds ) . ' )';
            }

            $dbw->delete( 'archive',
                $toDeleteConds,
                __METHOD__ );
        }

        $status = Status::newGood( $restored );

        if ( $failedRevisionCount > 0 ) {
            $status->warning(
                wfMessage( 'undeleterevision-duplicate-revid', $failedRevisionCount ) );
        }

        // Was anything restored at all?
        if ( $restored ) {
            $created = (bool)$newid;
            // Attach the latest revision to the page...
            // XXX: updateRevisionOn should probably move into a PageStore service.
            $wasnew = $article->updateIfNewerOn( $dbw, $legacyRevision );
            if ( $created || $wasnew ) {
                // Update site stats, link tables, etc
                // TODO: use DerivedPageDataUpdater from If610c68f4912e!
                $article->doEditUpdates(
                    $legacyRevision,
                    User::newFromName( $revision->getUser( RevisionRecord::RAW )->getName(), false ),
                    [
                        'created' => $created,
                        'oldcountable' => $oldcountable,
                        'restored' => true
                    ]
                );
            }

            Hooks::run( 'ArticleUndelete',
                [ &$this->title, $created, $comment, $oldPageId, $restoredPages ] );
            if ( $this->title->getNamespace() == NS_FILE ) {
                DeferredUpdates::addUpdate(
                    new HTMLCacheUpdate( $this->title, 'imagelinks', 'file-restore' )
                );
            }
        }

        $dbw->endAtomic( __METHOD__ );

        return $status;
    }

    public function getFileStatus() {
        return $this->fileStatus;
    }

    public function getRevisionStatus() {
        return $this->revisionStatus;
    }
}