FileBackend.php

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<?php
abstract class FileBackend {
    protected $name; // string; unique backend name
    protected $wikiId; // string; unique wiki name
    protected $readOnly; // string; read-only explanation message
    protected $parallelize; // string; when to do operations in parallel
    protected $concurrency; // integer; how many operations can be done in parallel

    protected $lockManager;
    protected $fileJournal;

    public function __construct( array $config ) {
        $this->name = $config['name'];
        if ( !preg_match( '!^[a-zA-Z0-9-_]{1,255}$!', $this->name ) ) {
            throw new MWException( "Backend name `{$this->name}` is invalid." );
        }
        $this->wikiId = isset( $config['wikiId'] )
            ? $config['wikiId']
            : wfWikiID(); // e.g. "my_wiki-en_"
        $this->lockManager = ( $config['lockManager'] instanceof LockManager )
            ? $config['lockManager']
            : LockManagerGroup::singleton( $this->wikiId )->get( $config['lockManager'] );
        $this->fileJournal = isset( $config['fileJournal'] )
            ? ( ( $config['fileJournal'] instanceof FileJournal )
                ? $config['fileJournal']
                : FileJournal::factory( $config['fileJournal'], $this->name ) )
            : FileJournal::factory( array( 'class' => 'NullFileJournal' ), $this->name );
        $this->readOnly = isset( $config['readOnly'] )
            ? (string)$config['readOnly']
            : '';
        $this->parallelize = isset( $config['parallelize'] )
            ? (string)$config['parallelize']
            : 'off';
        $this->concurrency = isset( $config['concurrency'] )
            ? (int)$config['concurrency']
            : 50;
    }

    final public function getName() {
        return $this->name;
    }

    final public function getWikiId() {
        return $this->wikiId;
    }

    final public function isReadOnly() {
        return ( $this->readOnly != '' );
    }

    final public function getReadOnlyReason() {
        return ( $this->readOnly != '' ) ? $this->readOnly : false;
    }

    final public function doOperations( array $ops, array $opts = array() ) {
        if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        if ( !count( $ops ) ) {
            return Status::newGood(); // nothing to do
        }
        if ( empty( $opts['force'] ) ) { // sanity
            unset( $opts['nonLocking'] );
        }
        foreach ( $ops as &$op ) {
            if ( isset( $op['disposition'] ) ) { // b/c (MW 1.20)
                $op['headers']['Content-Disposition'] = $op['disposition'];
            }
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doOperationsInternal( $ops, $opts );
    }

    abstract protected function doOperationsInternal( array $ops, array $opts );

    final public function doOperation( array $op, array $opts = array() ) {
        return $this->doOperations( array( $op ), $opts );
    }

    final public function create( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'create' ) + $params, $opts );
    }

    final public function store( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'store' ) + $params, $opts );
    }

    final public function copy( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'copy' ) + $params, $opts );
    }

    final public function move( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'move' ) + $params, $opts );
    }

    final public function delete( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'delete' ) + $params, $opts );
    }

    final public function describe( array $params, array $opts = array() ) {
        return $this->doOperation( array( 'op' => 'describe' ) + $params, $opts );
    }

    final public function doQuickOperations( array $ops, array $opts = array() ) {
        if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        if ( !count( $ops ) ) {
            return Status::newGood(); // nothing to do
        }
        foreach ( $ops as &$op ) {
            $op['overwrite'] = true; // avoids RTTs in key/value stores
            if ( isset( $op['disposition'] ) ) { // b/c (MW 1.20)
                $op['headers']['Content-Disposition'] = $op['disposition'];
            }
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doQuickOperationsInternal( $ops );
    }

    abstract protected function doQuickOperationsInternal( array $ops );

    final public function doQuickOperation( array $op ) {
        return $this->doQuickOperations( array( $op ) );
    }

    final public function quickCreate( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'create' ) + $params );
    }

    final public function quickStore( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'store' ) + $params );
    }

    final public function quickCopy( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'copy' ) + $params );
    }

    final public function quickMove( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'move' ) + $params );
    }

    final public function quickDelete( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'delete' ) + $params );
    }

    final public function quickDescribe( array $params ) {
        return $this->doQuickOperation( array( 'op' => 'describe' ) + $params );
    }

    abstract public function concatenate( array $params );

    final public function prepare( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doPrepare( $params );
    }

    abstract protected function doPrepare( array $params );

    final public function secure( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doSecure( $params );
    }

    abstract protected function doSecure( array $params );

    final public function publish( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doPublish( $params );
    }

    abstract protected function doPublish( array $params );

    final public function clean( array $params ) {
        if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
            return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly );
        }
        $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
        return $this->doClean( $params );
    }

    abstract protected function doClean( array $params );

    final protected function getScopedPHPBehaviorForOps() {
        if ( php_sapi_name() != 'cli' ) { // http://bugs.php.net/bug.php?id=47540
            $old = ignore_user_abort( true ); // avoid half-finished operations
            return new ScopedCallback( function() use ( $old ) {
                ignore_user_abort( $old );
            } );
        }
        return null;
    }

    abstract public function fileExists( array $params );

    abstract public function getFileTimestamp( array $params );

    final public function getFileContents( array $params ) {
        $contents = $this->getFileContentsMulti(
            array( 'srcs' => array( $params['src'] ) ) + $params );

        return $contents[$params['src']];
    }

    abstract public function getFileContentsMulti( array $params );

    abstract public function getFileSize( array $params );

    abstract public function getFileStat( array $params );

    abstract public function getFileSha1Base36( array $params );

    abstract public function getFileProps( array $params );

    abstract public function streamFile( array $params );

    final public function getLocalReference( array $params ) {
        $fsFiles = $this->getLocalReferenceMulti(
            array( 'srcs' => array( $params['src'] ) ) + $params );

        return $fsFiles[$params['src']];
    }

    abstract public function getLocalReferenceMulti( array $params );

    final public function getLocalCopy( array $params ) {
        $tmpFiles = $this->getLocalCopyMulti(
            array( 'srcs' => array( $params['src'] ) ) + $params );

        return $tmpFiles[$params['src']];
    }

    abstract public function getLocalCopyMulti( array $params );

    abstract public function getFileHttpUrl( array $params );

    abstract public function directoryExists( array $params );

    abstract public function getDirectoryList( array $params );

    final public function getTopDirectoryList( array $params ) {
        return $this->getDirectoryList( array( 'topOnly' => true ) + $params );
    }

    abstract public function getFileList( array $params );

    final public function getTopFileList( array $params ) {
        return $this->getFileList( array( 'topOnly' => true ) + $params );
    }

    public function preloadCache( array $paths ) {}

    public function clearCache( array $paths = null ) {}

    final public function lockFiles( array $paths, $type ) {
        $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
        return $this->lockManager->lock( $paths, $type );
    }

    final public function unlockFiles( array $paths, $type ) {
        $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
        return $this->lockManager->unlock( $paths, $type );
    }

    final public function getScopedFileLocks( array $paths, $type, Status $status ) {
        if ( $type === 'mixed' ) {
            foreach ( $paths as &$typePaths ) {
                $typePaths = array_map( 'FileBackend::normalizeStoragePath', $typePaths );
            }
        } else {
            $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
        }
        return ScopedLock::factory( $this->lockManager, $paths, $type, $status );
    }

    abstract public function getScopedLocksForOps( array $ops, Status $status );

    final public function getRootStoragePath() {
        return "mwstore://{$this->name}";
    }

    final public function getContainerStoragePath( $container ) {
        return $this->getRootStoragePath() . "/{$container}";
    }

    final public function getJournal() {
        return $this->fileJournal;
    }

    final public static function isStoragePath( $path ) {
        return ( strpos( $path, 'mwstore://' ) === 0 );
    }

    final public static function splitStoragePath( $storagePath ) {
        if ( self::isStoragePath( $storagePath ) ) {
            // Remove the "mwstore://" prefix and split the path
            $parts = explode( '/', substr( $storagePath, 10 ), 3 );
            if ( count( $parts ) >= 2 && $parts[0] != '' && $parts[1] != '' ) {
                if ( count( $parts ) == 3 ) {
                    return $parts; // e.g. "backend/container/path"
                } else {
                    return array( $parts[0], $parts[1], '' ); // e.g. "backend/container"
                }
            }
        }
        return array( null, null, null );
    }

    final public static function normalizeStoragePath( $storagePath ) {
        list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
        if ( $relPath !== null ) { // must be for this backend
            $relPath = self::normalizeContainerPath( $relPath );
            if ( $relPath !== null ) {
                return ( $relPath != '' )
                    ? "mwstore://{$backend}/{$container}/{$relPath}"
                    : "mwstore://{$backend}/{$container}";
            }
        }
        return null;
    }

    final public static function parentStoragePath( $storagePath ) {
        $storagePath = dirname( $storagePath );
        list( , , $rel ) = self::splitStoragePath( $storagePath );
        return ( $rel === null ) ? null : $storagePath;
    }

    final public static function extensionFromPath( $path ) {
        $i = strrpos( $path, '.' );
        return strtolower( $i ? substr( $path, $i + 1 ) : '' );
    }

    final public static function isPathTraversalFree( $path ) {
        return ( self::normalizeContainerPath( $path ) !== null );
    }

    final public static function makeContentDisposition( $type, $filename = '' ) {
        $parts = array();

        $type = strtolower( $type );
        if ( !in_array( $type, array( 'inline', 'attachment' ) ) ) {
            throw new MWException( "Invalid Content-Disposition type '$type'." );
        }
        $parts[] = $type;

        if ( strlen( $filename ) ) {
            $parts[] = "filename*=UTF-8''" . rawurlencode( basename( $filename ) );
        }

        return implode( ';', $parts );
    }

    final protected static function normalizeContainerPath( $path ) {
        // Normalize directory separators
        $path = strtr( $path, '\\', '/' );
        // Collapse any consecutive directory separators
        $path = preg_replace( '![/]{2,}!', '/', $path );
        // Remove any leading directory separator
        $path = ltrim( $path, '/' );
        // Use the same traversal protection as Title::secureAndSplit()
        if ( strpos( $path, '.' ) !== false ) {
            if (
                $path === '.' ||
                $path === '..' ||
                strpos( $path, './' ) === 0 ||
                strpos( $path, '../' ) === 0 ||
                strpos( $path, '/./' ) !== false ||
                strpos( $path, '/../' ) !== false
            ) {
                return null;
            }
        }
        return $path;
    }
}

class FileBackendError extends MWException {}