Merge "Begin exposing SiteConfiguration via site contexts"

[mediawiki.git] / includes / filerepo / LocalRepo.php

<?php
/**
 * Local repository that stores files in the local filesystem and registers them
 * in the wiki's own database.
 *
 * 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 FileRepo
 */

/**
 * A repository that stores files in the local filesystem and registers them
 * in the wiki's own database. This is the most commonly used repository class.
 *
 * @ingroup FileRepo
 */
class LocalRepo extends FileRepo {
        /** @var array */
        protected $fileFactory = array( 'LocalFile', 'newFromTitle' );

        /** @var array */
        protected $fileFactoryKey = array( 'LocalFile', 'newFromKey' );

        /** @var array */
        protected $fileFromRowFactory = array( 'LocalFile', 'newFromRow' );

        /** @var array */
        protected $oldFileFromRowFactory = array( 'OldLocalFile', 'newFromRow' );

        /** @var array */
        protected $oldFileFactory = array( 'OldLocalFile', 'newFromTitle' );

        /** @var array */
        protected $oldFileFactoryKey = array( 'OldLocalFile', 'newFromKey' );

        /**
         * @throws MWException
         * @param array $row
         * @return LocalFile
         */
        function newFileFromRow( $row ) {
                if ( isset( $row->img_name ) ) {
                        return call_user_func( $this->fileFromRowFactory, $row, $this );
                } elseif ( isset( $row->oi_name ) ) {
                        return call_user_func( $this->oldFileFromRowFactory, $row, $this );
                } else {
                        throw new MWException( __METHOD__ . ': invalid row' );
                }
        }

        /**
         * @param Title $title
         * @param string $archiveName
         * @return OldLocalFile
         */
        function newFromArchiveName( $title, $archiveName ) {
                return OldLocalFile::newFromArchiveName( $title, $this, $archiveName );
        }

        /**
         * Delete files in the deleted directory if they are not referenced in the
         * filearchive table. This needs to be done in the repo because it needs to
         * interleave database locks with file operations, which is potentially a
         * remote operation.
         *
         * @param array $storageKeys
         *
         * @return FileRepoStatus
         */
        function cleanupDeletedBatch( array $storageKeys ) {
                $backend = $this->backend; // convenience
                $root = $this->getZonePath( 'deleted' );
                $dbw = $this->getMasterDB();
                $status = $this->newGood();
                $storageKeys = array_unique( $storageKeys );
                foreach ( $storageKeys as $key ) {
                        $hashPath = $this->getDeletedHashPath( $key );
                        $path = "$root/$hashPath$key";
                        $dbw->begin( __METHOD__ );
                        // Check for usage in deleted/hidden files and pre-emptively
                        // lock the key to avoid any future use until we are finished.
                        $deleted = $this->deletedFileHasKey( $key, 'lock' );
                        $hidden = $this->hiddenFileHasKey( $key, 'lock' );
                        if ( !$deleted && !$hidden ) { // not in use now
                                wfDebug( __METHOD__ . ": deleting $key\n" );
                                $op = array( 'op' => 'delete', 'src' => $path );
                                if ( !$backend->doOperation( $op )->isOK() ) {
                                        $status->error( 'undelete-cleanup-error', $path );
                                        $status->failCount++;
                                }
                        } else {
                                wfDebug( __METHOD__ . ": $key still in use\n" );
                                $status->successCount++;
                        }
                        $dbw->commit( __METHOD__ );
                }

                return $status;
        }

        /**
         * Check if a deleted (filearchive) file has this sha1 key
         *
         * @param string $key File storage key (base-36 sha1 key with file extension)
         * @param string|null $lock Use "lock" to lock the row via FOR UPDATE
         * @return bool File with this key is in use
         */
        protected function deletedFileHasKey( $key, $lock = null ) {
                $options = ( $lock === 'lock' ) ? array( 'FOR UPDATE' ) : array();

                $dbw = $this->getMasterDB();

                return (bool)$dbw->selectField( 'filearchive', '1',
                        array( 'fa_storage_group' => 'deleted', 'fa_storage_key' => $key ),
                        __METHOD__, $options
                );
        }

        /**
         * Check if a hidden (revision delete) file has this sha1 key
         *
         * @param string $key File storage key (base-36 sha1 key with file extension)
         * @param string|null $lock Use "lock" to lock the row via FOR UPDATE
         * @return bool File with this key is in use
         */
        protected function hiddenFileHasKey( $key, $lock = null ) {
                $options = ( $lock === 'lock' ) ? array( 'FOR UPDATE' ) : array();

                $sha1 = self::getHashFromKey( $key );
                $ext = File::normalizeExtension( substr( $key, strcspn( $key, '.' ) + 1 ) );

                $dbw = $this->getMasterDB();

                return (bool)$dbw->selectField( 'oldimage', '1',
                        array( 'oi_sha1' => $sha1,
                                'oi_archive_name ' . $dbw->buildLike( $dbw->anyString(), ".$ext" ),
                                $dbw->bitAnd( 'oi_deleted', File::DELETED_FILE ) => File::DELETED_FILE ),
                        __METHOD__, $options
                );
        }

        /**
         * Gets the SHA1 hash from a storage key
         *
         * @param string $key
         * @return string
         */
        public static function getHashFromKey( $key ) {
                return strtok( $key, '.' );
        }

        /**
         * Checks if there is a redirect named as $title
         *
         * @param Title $title Title of file
         * @return bool
         */
        function checkRedirect( Title $title ) {
                global $wgMemc;

                $title = File::normalizeTitle( $title, 'exception' );

                $memcKey = $this->getSharedCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
                if ( $memcKey === false ) {
                        $memcKey = $this->getLocalCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
                        $expiry = 300; // no invalidation, 5 minutes
                } else {
                        $expiry = 86400; // has invalidation, 1 day
                }
                $cachedValue = $wgMemc->get( $memcKey );
                if ( $cachedValue === ' ' || $cachedValue === '' ) {
                        // Does not exist
                        return false;
                } elseif ( strval( $cachedValue ) !== '' && $cachedValue !== ' PURGED' ) {
                        return Title::newFromText( $cachedValue, NS_FILE );
                } // else $cachedValue is false or null: cache miss

                $id = $this->getArticleID( $title );
                if ( !$id ) {
                        $wgMemc->add( $memcKey, " ", $expiry );

                        return false;
                }
                $dbr = $this->getSlaveDB();
                $row = $dbr->selectRow(
                        'redirect',
                        array( 'rd_title', 'rd_namespace' ),
                        array( 'rd_from' => $id ),
                        __METHOD__
                );

                if ( $row && $row->rd_namespace == NS_FILE ) {
                        $targetTitle = Title::makeTitle( $row->rd_namespace, $row->rd_title );
                        $wgMemc->add( $memcKey, $targetTitle->getDBkey(), $expiry );

                        return $targetTitle;
                } else {
                        $wgMemc->add( $memcKey, '', $expiry );

                        return false;
                }
        }

        /**
         * Function link Title::getArticleID().
         * We can't say Title object, what database it should use, so we duplicate that function here.
         *
         * @param Title $title
         * @return bool|int|mixed
         */
        protected function getArticleID( $title ) {
                if ( !$title instanceof Title ) {
                        return 0;
                }
                $dbr = $this->getSlaveDB();
                $id = $dbr->selectField(
                        'page', // Table
                        'page_id', //Field
                        array( //Conditions
                                'page_namespace' => $title->getNamespace(),
                                'page_title' => $title->getDBkey(),
                        ),
                        __METHOD__ //Function name
                );

                return $id;
        }

        public function findFiles( array $items ) {
                $finalFiles = array(); // map of (DB key => corresponding File) for matches

                $searchSet = array(); // map of (DB key => normalized search params)
                foreach ( $items as $item ) {
                        $title = is_array( $item )
                                ? File::normalizeTitle( $item['title'] )
                                : File::normalizeTitle( $item );
                        if ( $title ) { // valid title
                                $searchSet[$title->getDbKey()] = ( is_array( $item ) ? $item : array() );
                        }
                }

                $fileMatchesSearch = function( File $file, array $search ) {
                        // Note: file name comparison done elsewhere (to handle redirects)
                        return (
                                $file->exists() &&
                                (
                                        ( empty( $search['time'] ) && !$file->isOld() ) ||
                                        ( !empty( $search['time'] ) && $search['time'] === $file->getTimestamp() )
                                ) &&
                                ( !empty( $search['private'] ) || !$file->isDeleted( File::DELETED_FILE ) ) &&
                                $file->userCan( File::DELETED_FILE )
                        );
                };

                $repo = $this;
                $applyMatchingFiles = function( ResultWrapper $res, &$searchSet, &$finalFiles )
                        use ( $repo, $fileMatchesSearch )
                {
                        foreach ( $res as $row ) {
                                $possFile = $repo->newFileFromRow( $row );
                                $dbKey = $possFile->getName();
                                // There must have been a search for this DB Key
                                if ( $fileMatchesSearch( $possFile, $searchSet[$dbKey] ) ) {
                                        $finalFiles[$dbKey] = $possFile;
                                        unset( $searchSet[$dbKey] );
                                }
                        }
                };

                $dbr = $this->getSlaveDB();

                // Query image table
                $imgNames = array_keys( $searchSet );
                if ( count( $imgNames ) ) {
                        $res = $dbr->select( 'image',
                                LocalFile::selectFields(), array( 'img_name' => $imgNames ), __METHOD__ );
                        $applyMatchingFiles( $res, $searchSet, $finalFiles );
                }

                // Query old image table
                $oiConds = array(); // WHERE clause array for each file
                foreach ( $searchSet as $dbKey => $search ) {
                        if ( isset( $search['params']['time'] ) ) {
                                $oiConds[] = $dbr->makeList( array( 'oi_name' => $dbKey,
                                        'oi_timestamp' => $dbr->timestamp( $search['params']['time'] ) ), LIST_AND );
                        }
                }
                if ( count( $oiConds ) ) {
                        $res = $dbr->select( 'oldimage',
                                OldLocalFile::selectFields(), $dbr->makeList( $oiConds, LIST_OR ), __METHOD__ );
                        $applyMatchingFiles( $res, $searchSet, $finalFiles );
                }

                // Check for redirects...
                foreach ( $searchSet as $dbKey => $search ) {
                        if ( !empty( $search['ignoreRedirect'] ) ) {
                                continue;
                        }
                        $title = File::normalizeTitle( $dbKey );
                        $redir = $this->checkRedirect( $title ); // hopefully hits memcached
                        if ( $redir && $redir->getNamespace() == NS_FILE ) {
                                $possFile = $this->newFile( $redir );
                                if ( $possFile && $fileMatchesSearch( $possFile, $search ) ) {
                                        $possFile->redirectedFrom( $title->getDBkey() );
                                        $finalFiles[$dbKey] = $possFile;
                                }
                        }
                }

                return $finalFiles;
        }

        /**
         * Get an array or iterator of file objects for files that have a given
         * SHA-1 content hash.
         *
         * @param string $hash a sha1 hash to look for
         * @return array
         */
        function findBySha1( $hash ) {
                $dbr = $this->getSlaveDB();
                $res = $dbr->select(
                        'image',
                        LocalFile::selectFields(),
                        array( 'img_sha1' => $hash ),
                        __METHOD__,
                        array( 'ORDER BY' => 'img_name' )
                );

                $result = array();
                foreach ( $res as $row ) {
                        $result[] = $this->newFileFromRow( $row );
                }
                $res->free();

                return $result;
        }

        /**
         * Get an array of arrays or iterators of file objects for files that
         * have the given SHA-1 content hashes.
         *
         * Overrides generic implementation in FileRepo for performance reason
         *
         * @param array $hashes An array of hashes
         * @return array An Array of arrays or iterators of file objects and the hash as key
         */
        function findBySha1s( array $hashes ) {
                if ( !count( $hashes ) ) {
                        return array(); //empty parameter
                }

                $dbr = $this->getSlaveDB();
                $res = $dbr->select(
                        'image',
                        LocalFile::selectFields(),
                        array( 'img_sha1' => $hashes ),
                        __METHOD__,
                        array( 'ORDER BY' => 'img_name' )
                );

                $result = array();
                foreach ( $res as $row ) {
                        $file = $this->newFileFromRow( $row );
                        $result[$file->getSha1()][] = $file;
                }
                $res->free();

                return $result;
        }

        /**
         * Return an array of files where the name starts with $prefix.
         *
         * @param string $prefix The prefix to search for
         * @param int $limit The maximum amount of files to return
         * @return array
         */
        public function findFilesByPrefix( $prefix, $limit ) {
                $selectOptions = array( 'ORDER BY' => 'img_name', 'LIMIT' => intval( $limit ) );

                // Query database
                $dbr = $this->getSlaveDB();
                $res = $dbr->select(
                        'image',
                        LocalFile::selectFields(),
                        'img_name ' . $dbr->buildLike( $prefix, $dbr->anyString() ),
                        __METHOD__,
                        $selectOptions
                );

                // Build file objects
                $files = array();
                foreach ( $res as $row ) {
                        $files[] = $this->newFileFromRow( $row );
                }

                return $files;
        }

        /**
         * Get a connection to the slave DB
         * @return DatabaseBase
         */
        function getSlaveDB() {
                return wfGetDB( DB_SLAVE );
        }

        /**
         * Get a connection to the master DB
         * @return DatabaseBase
         */
        function getMasterDB() {
                return wfGetDB( DB_MASTER );
        }

        /**
         * Get a key on the primary cache for this repository.
         * Returns false if the repository's cache is not accessible at this site.
         * The parameters are the parts of the key, as for wfMemcKey().
         *
         * @return string
         */
        function getSharedCacheKey( /*...*/ ) {
                $args = func_get_args();

                return call_user_func_array( 'wfMemcKey', $args );
        }

        /**
         * Invalidates image redirect cache related to that image
         *
         * @param Title $title Title of page
         * @return void
         */
        function invalidateImageRedirect( Title $title ) {
                global $wgMemc;
                $memcKey = $this->getSharedCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
                if ( $memcKey ) {
                        // Set a temporary value for the cache key, to ensure
                        // that this value stays purged long enough so that
                        // it isn't refreshed with a stale value due to a
                        // lagged slave.
                        $wgMemc->set( $memcKey, ' PURGED', 12 );
                }
        }
}