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Diffstat (limited to 'includes/filebackend/FileBackend.php')
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diff --git a/includes/filebackend/FileBackend.php b/includes/filebackend/FileBackend.php new file mode 100644 index 00000000..76c761b0 --- /dev/null +++ b/includes/filebackend/FileBackend.php @@ -0,0 +1,1173 @@ +<?php +/** + * @defgroup FileBackend File backend + * @ingroup FileRepo + * + * File backend is used to interact with file storage systems, + * such as the local file system, NFS, or cloud storage systems. + */ + +/** + * Base class for all file backends. + * + * 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 FileBackend + * @author Aaron Schulz + */ + +/** + * @brief Base class for all file backend classes (including multi-write backends). + * + * This class defines the methods as abstract that subclasses must implement. + * Outside callers can assume that all backends will have these functions. + * + * All "storage paths" are of the format "mwstore://<backend>/<container>/<path>". + * The "<path>" portion is a relative path that uses UNIX file system (FS) + * notation, though any particular backend may not actually be using a local + * filesystem. Therefore, the relative paths are only virtual. + * + * Backend contents are stored under wiki-specific container names by default. + * For legacy reasons, this has no effect for the FS backend class, and per-wiki + * segregation must be done by setting the container paths appropriately. + * + * FS-based backends are somewhat more restrictive due to the existence of real + * directory files; a regular file cannot have the same name as a directory. Other + * backends with virtual directories may not have this limitation. Callers should + * store files in such a way that no files and directories are under the same path. + * + * Methods of subclasses should avoid throwing exceptions at all costs. + * As a corollary, external dependencies should be kept to a minimum. + * + * @ingroup FileBackend + * @since 1.19 + */ +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 + + /** @var LockManager */ + protected $lockManager; + /** @var FileJournal */ + protected $fileJournal; + + /** + * Create a new backend instance from configuration. + * This should only be called from within FileBackendGroup. + * + * $config includes: + * - name : The unique name of this backend. + * This should consist of alphanumberic, '-', and '_' characters. + * This name should not be changed after use. + * - wikiId : Prefix to container names that is unique to this wiki. + * It should only consist of alphanumberic, '-', and '_' characters. + * - lockManager : Registered name of a file lock manager to use. + * - fileJournal : File journal configuration; see FileJournal::factory(). + * Journals simply log changes to files stored in the backend. + * - readOnly : Write operations are disallowed if this is a non-empty string. + * It should be an explanation for the backend being read-only. + * - parallelize : When to do file operations in parallel (when possible). + * Allowed values are "implicit", "explicit" and "off". + * - concurrency : How many file operations can be done in parallel. + * + * @param $config Array + * @throws MWException + */ + 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()->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; + } + + /** + * Get the unique backend name. + * We may have multiple different backends of the same type. + * For example, we can have two Swift backends using different proxies. + * + * @return string + */ + final public function getName() { + return $this->name; + } + + /** + * Get the wiki identifier used for this backend (possibly empty) + * + * @return string + * @since 1.20 + */ + final public function getWikiId() { + return $this->wikiId; + } + + /** + * Check if this backend is read-only + * + * @return bool + */ + final public function isReadOnly() { + return ( $this->readOnly != '' ); + } + + /** + * Get an explanatory message if this backend is read-only + * + * @return string|bool Returns false if the backend is not read-only + */ + final public function getReadOnlyReason() { + return ( $this->readOnly != '' ) ? $this->readOnly : false; + } + + /** + * This is the main entry point into the backend for write operations. + * Callers supply an ordered list of operations to perform as a transaction. + * Files will be locked, the stat cache cleared, and then the operations attempted. + * If any serious errors occur, all attempted operations will be rolled back. + * + * $ops is an array of arrays. The outer array holds a list of operations. + * Each inner array is a set of key value pairs that specify an operation. + * + * Supported operations and their parameters. The supported actions are: + * - create + * - store + * - copy + * - move + * - delete + * - null + * + * a) Create a new file in storage with the contents of a string + * @code + * array( + * 'op' => 'create', + * 'dst' => <storage path>, + * 'content' => <string of new file contents>, + * 'overwrite' => <boolean>, + * 'overwriteSame' => <boolean>, + * 'disposition' => <Content-Disposition header value> + * ); + * @endcode + * + * b) Copy a file system file into storage + * @code + * array( + * 'op' => 'store', + * 'src' => <file system path>, + * 'dst' => <storage path>, + * 'overwrite' => <boolean>, + * 'overwriteSame' => <boolean>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * + * c) Copy a file within storage + * @code + * array( + * 'op' => 'copy', + * 'src' => <storage path>, + * 'dst' => <storage path>, + * 'overwrite' => <boolean>, + * 'overwriteSame' => <boolean>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * + * d) Move a file within storage + * @code + * array( + * 'op' => 'move', + * 'src' => <storage path>, + * 'dst' => <storage path>, + * 'overwrite' => <boolean>, + * 'overwriteSame' => <boolean>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * + * e) Delete a file within storage + * @code + * array( + * 'op' => 'delete', + * 'src' => <storage path>, + * 'ignoreMissingSource' => <boolean> + * ) + * @endcode + * + * f) Do nothing (no-op) + * @code + * array( + * 'op' => 'null', + * ) + * @endcode + * + * Boolean flags for operations (operation-specific): + * - ignoreMissingSource : The operation will simply succeed and do + * nothing if the source file does not exist. + * - overwrite : Any destination file will be overwritten. + * - overwriteSame : An error will not be given if a file already + * exists at the destination that has the same + * contents as the new contents to be written there. + * - disposition : When supplied, the backend will add a Content-Disposition + * header when GETs/HEADs of the destination file are made. + * Backends that don't support file metadata will ignore this. + * See http://tools.ietf.org/html/rfc6266 (since 1.20). + * + * $opts is an associative of boolean flags, including: + * - force : Operation precondition errors no longer trigger an abort. + * Any remaining operations are still attempted. Unexpected + * failures may still cause remaning operations to be aborted. + * - nonLocking : No locks are acquired for the operations. + * This can increase performance for non-critical writes. + * This has no effect unless the 'force' flag is set. + * - allowStale : Don't require the latest available data. + * This can increase performance for non-critical writes. + * This has no effect unless the 'force' flag is set. + * - nonJournaled : Don't log this operation batch in the file journal. + * This limits the ability of recovery scripts. + * - parallelize : Try to do operations in parallel when possible. + * - bypassReadOnly : Allow writes in read-only mode (since 1.20). + * - preserveCache : Don't clear the process cache before checking files. + * This should only be used if all entries in the process + * cache were added after the files were already locked (since 1.20). + * + * @remarks Remarks on locking: + * File system paths given to operations should refer to files that are + * already locked or otherwise safe from modification from other processes. + * Normally these files will be new temp files, which should be adequate. + * + * @par Return value: + * + * This returns a Status, which contains all warnings and fatals that occurred + * during the operation. The 'failCount', 'successCount', and 'success' members + * will reflect each operation attempted. + * + * The status will be "OK" unless: + * - a) unexpected operation errors occurred (network partitions, disk full...) + * - b) significant operation errors occurred and 'force' was not set + * + * @param $ops Array List of operations to execute in order + * @param $opts Array Batch operation options + * @return Status + */ + 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 ( empty( $opts['force'] ) ) { // sanity + unset( $opts['nonLocking'] ); + unset( $opts['allowStale'] ); + } + $opts['concurrency'] = 1; // off + if ( $this->parallelize === 'implicit' ) { + if ( !isset( $opts['parallelize'] ) || $opts['parallelize'] ) { + $opts['concurrency'] = $this->concurrency; + } + } elseif ( $this->parallelize === 'explicit' ) { + if ( !empty( $opts['parallelize'] ) ) { + $opts['concurrency'] = $this->concurrency; + } + } + return $this->doOperationsInternal( $ops, $opts ); + } + + /** + * @see FileBackend::doOperations() + */ + abstract protected function doOperationsInternal( array $ops, array $opts ); + + /** + * Same as doOperations() except it takes a single operation. + * If you are doing a batch of operations that should either + * all succeed or all fail, then use that function instead. + * + * @see FileBackend::doOperations() + * + * @param $op Array Operation + * @param $opts Array Operation options + * @return Status + */ + final public function doOperation( array $op, array $opts = array() ) { + return $this->doOperations( array( $op ), $opts ); + } + + /** + * Performs a single create operation. + * This sets $params['op'] to 'create' and passes it to doOperation(). + * + * @see FileBackend::doOperation() + * + * @param $params Array Operation parameters + * @param $opts Array Operation options + * @return Status + */ + final public function create( array $params, array $opts = array() ) { + return $this->doOperation( array( 'op' => 'create' ) + $params, $opts ); + } + + /** + * Performs a single store operation. + * This sets $params['op'] to 'store' and passes it to doOperation(). + * + * @see FileBackend::doOperation() + * + * @param $params Array Operation parameters + * @param $opts Array Operation options + * @return Status + */ + final public function store( array $params, array $opts = array() ) { + return $this->doOperation( array( 'op' => 'store' ) + $params, $opts ); + } + + /** + * Performs a single copy operation. + * This sets $params['op'] to 'copy' and passes it to doOperation(). + * + * @see FileBackend::doOperation() + * + * @param $params Array Operation parameters + * @param $opts Array Operation options + * @return Status + */ + final public function copy( array $params, array $opts = array() ) { + return $this->doOperation( array( 'op' => 'copy' ) + $params, $opts ); + } + + /** + * Performs a single move operation. + * This sets $params['op'] to 'move' and passes it to doOperation(). + * + * @see FileBackend::doOperation() + * + * @param $params Array Operation parameters + * @param $opts Array Operation options + * @return Status + */ + final public function move( array $params, array $opts = array() ) { + return $this->doOperation( array( 'op' => 'move' ) + $params, $opts ); + } + + /** + * Performs a single delete operation. + * This sets $params['op'] to 'delete' and passes it to doOperation(). + * + * @see FileBackend::doOperation() + * + * @param $params Array Operation parameters + * @param $opts Array Operation options + * @return Status + */ + final public function delete( array $params, array $opts = array() ) { + return $this->doOperation( array( 'op' => 'delete' ) + $params, $opts ); + } + + /** + * Perform a set of independent file operations on some files. + * + * This does no locking, nor journaling, and possibly no stat calls. + * Any destination files that already exist will be overwritten. + * This should *only* be used on non-original files, like cache files. + * + * Supported operations and their parameters: + * - create + * - store + * - copy + * - move + * - delete + * - null + * + * a) Create a new file in storage with the contents of a string + * @code + * array( + * 'op' => 'create', + * 'dst' => <storage path>, + * 'content' => <string of new file contents>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * b) Copy a file system file into storage + * @code + * array( + * 'op' => 'store', + * 'src' => <file system path>, + * 'dst' => <storage path>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * c) Copy a file within storage + * @code + * array( + * 'op' => 'copy', + * 'src' => <storage path>, + * 'dst' => <storage path>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * d) Move a file within storage + * @code + * array( + * 'op' => 'move', + * 'src' => <storage path>, + * 'dst' => <storage path>, + * 'disposition' => <Content-Disposition header value> + * ) + * @endcode + * e) Delete a file within storage + * @code + * array( + * 'op' => 'delete', + * 'src' => <storage path>, + * 'ignoreMissingSource' => <boolean> + * ) + * @endcode + * f) Do nothing (no-op) + * @code + * array( + * 'op' => 'null', + * ) + * @endcode + * + * @par Boolean flags for operations (operation-specific): + * - ignoreMissingSource : The operation will simply succeed and do + * nothing if the source file does not exist. + * - disposition : When supplied, the backend will add a Content-Disposition + * header when GETs/HEADs of the destination file are made. + * Backends that don't support file metadata will ignore this. + * See http://tools.ietf.org/html/rfc6266 (since 1.20). + * + * $opts is an associative of boolean flags, including: + * - bypassReadOnly : Allow writes in read-only mode (since 1.20) + * + * @par Return value: + * This returns a Status, which contains all warnings and fatals that occurred + * during the operation. The 'failCount', 'successCount', and 'success' members + * will reflect each operation attempted for the given files. The status will be + * considered "OK" as long as no fatal errors occurred. + * + * @param $ops Array Set of operations to execute + * @param $opts Array Batch operation options + * @return Status + * @since 1.20 + */ + 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 ); + } + foreach ( $ops as &$op ) { + $op['overwrite'] = true; // avoids RTTs in key/value stores + } + return $this->doQuickOperationsInternal( $ops ); + } + + /** + * @see FileBackend::doQuickOperations() + * @since 1.20 + */ + abstract protected function doQuickOperationsInternal( array $ops ); + + /** + * Same as doQuickOperations() except it takes a single operation. + * If you are doing a batch of operations, then use that function instead. + * + * @see FileBackend::doQuickOperations() + * + * @param $op Array Operation + * @return Status + * @since 1.20 + */ + final public function doQuickOperation( array $op ) { + return $this->doQuickOperations( array( $op ) ); + } + + /** + * Performs a single quick create operation. + * This sets $params['op'] to 'create' and passes it to doQuickOperation(). + * + * @see FileBackend::doQuickOperation() + * + * @param $params Array Operation parameters + * @return Status + * @since 1.20 + */ + final public function quickCreate( array $params ) { + return $this->doQuickOperation( array( 'op' => 'create' ) + $params ); + } + + /** + * Performs a single quick store operation. + * This sets $params['op'] to 'store' and passes it to doQuickOperation(). + * + * @see FileBackend::doQuickOperation() + * + * @param $params Array Operation parameters + * @return Status + * @since 1.20 + */ + final public function quickStore( array $params ) { + return $this->doQuickOperation( array( 'op' => 'store' ) + $params ); + } + + /** + * Performs a single quick copy operation. + * This sets $params['op'] to 'copy' and passes it to doQuickOperation(). + * + * @see FileBackend::doQuickOperation() + * + * @param $params Array Operation parameters + * @return Status + * @since 1.20 + */ + final public function quickCopy( array $params ) { + return $this->doQuickOperation( array( 'op' => 'copy' ) + $params ); + } + + /** + * Performs a single quick move operation. + * This sets $params['op'] to 'move' and passes it to doQuickOperation(). + * + * @see FileBackend::doQuickOperation() + * + * @param $params Array Operation parameters + * @return Status + * @since 1.20 + */ + final public function quickMove( array $params ) { + return $this->doQuickOperation( array( 'op' => 'move' ) + $params ); + } + + /** + * Performs a single quick delete operation. + * This sets $params['op'] to 'delete' and passes it to doQuickOperation(). + * + * @see FileBackend::doQuickOperation() + * + * @param $params Array Operation parameters + * @return Status + * @since 1.20 + */ + final public function quickDelete( array $params ) { + return $this->doQuickOperation( array( 'op' => 'delete' ) + $params ); + } + + /** + * Concatenate a list of storage files into a single file system file. + * The target path should refer to a file that is already locked or + * otherwise safe from modification from other processes. Normally, + * the file will be a new temp file, which should be adequate. + * + * @param $params Array Operation parameters + * $params include: + * - srcs : ordered source storage paths (e.g. chunk1, chunk2, ...) + * - dst : file system path to 0-byte temp file + * @return Status + */ + abstract public function concatenate( array $params ); + + /** + * Prepare a storage directory for usage. + * This will create any required containers and parent directories. + * Backends using key/value stores only need to create the container. + * + * The 'noAccess' and 'noListing' parameters works the same as in secure(), + * except they are only applied *if* the directory/container had to be created. + * These flags should always be set for directories that have private files. + * + * @param $params Array + * $params include: + * - dir : storage directory + * - noAccess : try to deny file access (since 1.20) + * - noListing : try to deny file listing (since 1.20) + * - bypassReadOnly : allow writes in read-only mode (since 1.20) + * @return Status + */ + final public function prepare( array $params ) { + if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) { + return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly ); + } + return $this->doPrepare( $params ); + } + + /** + * @see FileBackend::prepare() + */ + abstract protected function doPrepare( array $params ); + + /** + * Take measures to block web access to a storage directory and + * the container it belongs to. FS backends might add .htaccess + * files whereas key/value store backends might revoke container + * access to the storage user representing end-users in web requests. + * This is not guaranteed to actually do anything. + * + * @param $params Array + * $params include: + * - dir : storage directory + * - noAccess : try to deny file access + * - noListing : try to deny file listing + * - bypassReadOnly : allow writes in read-only mode (since 1.20) + * @return Status + */ + final public function secure( array $params ) { + if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) { + return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly ); + } + return $this->doSecure( $params ); + } + + /** + * @see FileBackend::secure() + */ + abstract protected function doSecure( array $params ); + + /** + * Remove measures to block web access to a storage directory and + * the container it belongs to. FS backends might remove .htaccess + * files whereas key/value store backends might grant container + * access to the storage user representing end-users in web requests. + * This essentially can undo the result of secure() calls. + * + * @param $params Array + * $params include: + * - dir : storage directory + * - access : try to allow file access + * - listing : try to allow file listing + * - bypassReadOnly : allow writes in read-only mode (since 1.20) + * @return Status + * @since 1.20 + */ + final public function publish( array $params ) { + if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) { + return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly ); + } + return $this->doPublish( $params ); + } + + /** + * @see FileBackend::publish() + */ + abstract protected function doPublish( array $params ); + + /** + * Delete a storage directory if it is empty. + * Backends using key/value stores may do nothing unless the directory + * is that of an empty container, in which case it will be deleted. + * + * @param $params Array + * $params include: + * - dir : storage directory + * - recursive : recursively delete empty subdirectories first (since 1.20) + * - bypassReadOnly : allow writes in read-only mode (since 1.20) + * @return Status + */ + final public function clean( array $params ) { + if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) { + return Status::newFatal( 'backend-fail-readonly', $this->name, $this->readOnly ); + } + return $this->doClean( $params ); + } + + /** + * @see FileBackend::clean() + */ + abstract protected function doClean( array $params ); + + /** + * Check if a file exists at a storage path in the backend. + * This returns false if only a directory exists at the path. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return bool|null Returns null on failure + */ + abstract public function fileExists( array $params ); + + /** + * Get the last-modified timestamp of the file at a storage path. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return string|bool TS_MW timestamp or false on failure + */ + abstract public function getFileTimestamp( array $params ); + + /** + * Get the contents of a file at a storage path in the backend. + * This should be avoided for potentially large files. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return string|bool Returns false on failure + */ + abstract public function getFileContents( array $params ); + + /** + * Get the size (bytes) of a file at a storage path in the backend. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return integer|bool Returns false on failure + */ + abstract public function getFileSize( array $params ); + + /** + * Get quick information about a file at a storage path in the backend. + * If the file does not exist, then this returns false. + * Otherwise, the result is an associative array that includes: + * - mtime : the last-modified timestamp (TS_MW) + * - size : the file size (bytes) + * Additional values may be included for internal use only. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return Array|bool|null Returns null on failure + */ + abstract public function getFileStat( array $params ); + + /** + * Get a SHA-1 hash of the file at a storage path in the backend. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return string|bool Hash string or false on failure + */ + abstract public function getFileSha1Base36( array $params ); + + /** + * Get the properties of the file at a storage path in the backend. + * Returns FSFile::placeholderProps() on failure. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return Array + */ + abstract public function getFileProps( array $params ); + + /** + * Stream the file at a storage path in the backend. + * If the file does not exists, an HTTP 404 error will be given. + * Appropriate HTTP headers (Status, Content-Type, Content-Length) + * will be sent if streaming began, while none will be sent otherwise. + * Implementations should flush the output buffer before sending data. + * + * @param $params Array + * $params include: + * - src : source storage path + * - headers : list of additional HTTP headers to send on success + * - latest : use the latest available data + * @return Status + */ + abstract public function streamFile( array $params ); + + /** + * Returns a file system file, identical to the file at a storage path. + * The file returned is either: + * - a) A local copy of the file at a storage path in the backend. + * The temporary copy will have the same extension as the source. + * - b) An original of the file at a storage path in the backend. + * Temporary files may be purged when the file object falls out of scope. + * + * Write operations should *never* be done on this file as some backends + * may do internal tracking or may be instances of FileBackendMultiWrite. + * In that later case, there are copies of the file that must stay in sync. + * Additionally, further calls to this function may return the same file. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return FSFile|null Returns null on failure + */ + abstract public function getLocalReference( array $params ); + + /** + * Get a local copy on disk of the file at a storage path in the backend. + * The temporary copy will have the same file extension as the source. + * Temporary files may be purged when the file object falls out of scope. + * + * @param $params Array + * $params include: + * - src : source storage path + * - latest : use the latest available data + * @return TempFSFile|null Returns null on failure + */ + abstract public function getLocalCopy( array $params ); + + /** + * Check if a directory exists at a given storage path. + * Backends using key/value stores will check if the path is a + * virtual directory, meaning there are files under the given directory. + * + * Storage backends with eventual consistency might return stale data. + * + * @param $params array + * $params include: + * - dir : storage directory + * @return bool|null Returns null on failure + * @since 1.20 + */ + abstract public function directoryExists( array $params ); + + /** + * Get an iterator to list *all* directories under a storage directory. + * If the directory is of the form "mwstore://backend/container", + * then all directories in the container will be listed. + * If the directory is of form "mwstore://backend/container/dir", + * then all directories directly under that directory will be listed. + * Results will be storage directories relative to the given directory. + * + * Storage backends with eventual consistency might return stale data. + * + * @param $params array + * $params include: + * - dir : storage directory + * - topOnly : only return direct child dirs of the directory + * @return Traversable|Array|null Returns null on failure + * @since 1.20 + */ + abstract public function getDirectoryList( array $params ); + + /** + * Same as FileBackend::getDirectoryList() except only lists + * directories that are immediately under the given directory. + * + * Storage backends with eventual consistency might return stale data. + * + * @param $params array + * $params include: + * - dir : storage directory + * @return Traversable|Array|null Returns null on failure + * @since 1.20 + */ + final public function getTopDirectoryList( array $params ) { + return $this->getDirectoryList( array( 'topOnly' => true ) + $params ); + } + + /** + * Get an iterator to list *all* stored files under a storage directory. + * If the directory is of the form "mwstore://backend/container", + * then all files in the container will be listed. + * If the directory is of form "mwstore://backend/container/dir", + * then all files under that directory will be listed. + * Results will be storage paths relative to the given directory. + * + * Storage backends with eventual consistency might return stale data. + * + * @param $params array + * $params include: + * - dir : storage directory + * - topOnly : only return direct child files of the directory (since 1.20) + * @return Traversable|Array|null Returns null on failure + */ + abstract public function getFileList( array $params ); + + /** + * Same as FileBackend::getFileList() except only lists + * files that are immediately under the given directory. + * + * Storage backends with eventual consistency might return stale data. + * + * @param $params array + * $params include: + * - dir : storage directory + * @return Traversable|Array|null Returns null on failure + * @since 1.20 + */ + final public function getTopFileList( array $params ) { + return $this->getFileList( array( 'topOnly' => true ) + $params ); + } + + /** + * Preload persistent file stat and property cache into in-process cache. + * This should be used when stat calls will be made on a known list of a many files. + * + * @param $paths Array Storage paths + * @return void + */ + public function preloadCache( array $paths ) {} + + /** + * Invalidate any in-process file stat and property cache. + * If $paths is given, then only the cache for those files will be cleared. + * + * @param $paths Array Storage paths (optional) + * @return void + */ + public function clearCache( array $paths = null ) {} + + /** + * Lock the files at the given storage paths in the backend. + * This will either lock all the files or none (on failure). + * + * Callers should consider using getScopedFileLocks() instead. + * + * @param $paths Array Storage paths + * @param $type integer LockManager::LOCK_* constant + * @return Status + */ + final public function lockFiles( array $paths, $type ) { + return $this->lockManager->lock( $paths, $type ); + } + + /** + * Unlock the files at the given storage paths in the backend. + * + * @param $paths Array Storage paths + * @param $type integer LockManager::LOCK_* constant + * @return Status + */ + final public function unlockFiles( array $paths, $type ) { + return $this->lockManager->unlock( $paths, $type ); + } + + /** + * Lock the files at the given storage paths in the backend. + * This will either lock all the files or none (on failure). + * On failure, the status object will be updated with errors. + * + * Once the return value goes out scope, the locks will be released and + * the status updated. Unlock fatals will not change the status "OK" value. + * + * @param $paths Array Storage paths + * @param $type integer LockManager::LOCK_* constant + * @param $status Status Status to update on lock/unlock + * @return ScopedLock|null Returns null on failure + */ + final public function getScopedFileLocks( array $paths, $type, Status $status ) { + return ScopedLock::factory( $this->lockManager, $paths, $type, $status ); + } + + /** + * Get an array of scoped locks needed for a batch of file operations. + * + * Normally, FileBackend::doOperations() handles locking, unless + * the 'nonLocking' param is passed in. This function is useful if you + * want the files to be locked for a broader scope than just when the + * files are changing. For example, if you need to update DB metadata, + * you may want to keep the files locked until finished. + * + * @see FileBackend::doOperations() + * + * @param $ops Array List of file operations to FileBackend::doOperations() + * @param $status Status Status to update on lock/unlock + * @return Array List of ScopedFileLocks or null values + * @since 1.20 + */ + abstract public function getScopedLocksForOps( array $ops, Status $status ); + + /** + * Get the root storage path of this backend. + * All container paths are "subdirectories" of this path. + * + * @return string Storage path + * @since 1.20 + */ + final public function getRootStoragePath() { + return "mwstore://{$this->name}"; + } + + /** + * Get the file journal object for this backend + * + * @return FileJournal + */ + final public function getJournal() { + return $this->fileJournal; + } + + /** + * Check if a given path is a "mwstore://" path. + * This does not do any further validation or any existence checks. + * + * @param $path string + * @return bool + */ + final public static function isStoragePath( $path ) { + return ( strpos( $path, 'mwstore://' ) === 0 ); + } + + /** + * Split a storage path into a backend name, a container name, + * and a relative file path. The relative path may be the empty string. + * This does not do any path normalization or traversal checks. + * + * @param $storagePath string + * @return Array (backend, container, rel object) or (null, null, null) + */ + 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 ); + } + + /** + * Normalize a storage path by cleaning up directory separators. + * Returns null if the path is not of the format of a valid storage path. + * + * @param $storagePath string + * @return string|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; + } + + /** + * Get the parent storage directory of a storage path. + * This returns a path like "mwstore://backend/container", + * "mwstore://backend/container/...", or null if there is no parent. + * + * @param $storagePath string + * @return string|null + */ + final public static function parentStoragePath( $storagePath ) { + $storagePath = dirname( $storagePath ); + list( $b, $cont, $rel ) = self::splitStoragePath( $storagePath ); + return ( $rel === null ) ? null : $storagePath; + } + + /** + * Get the final extension from a storage or FS path + * + * @param $path string + * @return string + */ + final public static function extensionFromPath( $path ) { + $i = strrpos( $path, '.' ); + return strtolower( $i ? substr( $path, $i + 1 ) : '' ); + } + + /** + * Check if a relative path has no directory traversals + * + * @param $path string + * @return bool + * @since 1.20 + */ + final public static function isPathTraversalFree( $path ) { + return ( self::normalizeContainerPath( $path ) !== null ); + } + + /** + * Build a Content-Disposition header value per RFC 6266. + * + * @param $type string One of (attachment, inline) + * @param $filename string Suggested file name (should not contain slashes) + * @return string + * @since 1.20 + */ + 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 ); + } + + /** + * Validate and normalize a relative storage path. + * Null is returned if the path involves directory traversal. + * Traversal is insecure for FS backends and broken for others. + * + * This uses the same traversal protection as Title::secureAndSplit(). + * + * @param $path string Storage path relative to a container + * @return string|null + */ + 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; + } +} |