3 * @defgroup FileBackend File backend
5 * File backend is used to interact with file storage systems,
6 * such as the local file system, NFS, or cloud storage systems.
10 * Base class for all file backends.
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 * http://www.gnu.org/copyleft/gpl.html
28 * @ingroup FileBackend
30 use Psr\Log\LoggerAwareInterface
;
31 use Psr\Log\LoggerInterface
;
32 use Wikimedia\ScopedCallback
;
33 use Psr\Log\NullLogger
;
36 * @brief Base class for all file backend classes (including multi-write backends).
38 * This class defines the methods as abstract that subclasses must implement.
39 * Outside callers can assume that all backends will have these functions.
41 * All "storage paths" are of the format "mwstore://<backend>/<container>/<path>".
42 * The "backend" portion is unique name for the application to refer to a backend, while
43 * the "container" portion is a top-level directory of the backend. The "path" portion
44 * is a relative path that uses UNIX file system (FS) notation, though any particular
45 * backend may not actually be using a local filesystem. Therefore, the relative paths
48 * Backend contents are stored under "domain"-specific container names by default.
49 * A domain is simply a logical umbrella for entities, such as those belonging to a certain
50 * application or portion of a website, for example. A domain can be local or global.
51 * Global (qualified) backends are achieved by configuring the "domain ID" to a constant.
52 * Global domains are simpler, but local domains can be used by choosing a domain ID based on
53 * the current context, such as which language of a website is being used.
55 * For legacy reasons, the FSFileBackend class allows manually setting the paths of
56 * containers to ones that do not respect the "domain ID".
58 * In key/value (object) stores, containers are the only hierarchy (the rest is emulated).
59 * FS-based backends are somewhat more restrictive due to the existence of real
60 * directory files; a regular file cannot have the same name as a directory. Other
61 * backends with virtual directories may not have this limitation. Callers should
62 * store files in such a way that no files and directories are under the same path.
64 * In general, this class allows for callers to access storage through the same
65 * interface, without regard to the underlying storage system. However, calling code
66 * must follow certain patterns and be aware of certain things to ensure compatibility:
67 * - a) Always call prepare() on the parent directory before trying to put a file there;
68 * key/value stores only need the container to exist first, but filesystems need
69 * all the parent directories to exist first (prepare() is aware of all this)
70 * - b) Always call clean() on a directory when it might become empty to avoid empty
71 * directory buildup on filesystems; key/value stores never have empty directories,
72 * so doing this helps preserve consistency in both cases
73 * - c) Likewise, do not rely on the existence of empty directories for anything;
74 * calling directoryExists() on a path that prepare() was previously called on
75 * will return false for key/value stores if there are no files under that path
76 * - d) Never alter the resulting FSFile returned from getLocalReference(), as it could
77 * either be a copy of the source file in /tmp or the original source file itself
78 * - e) Use a file layout that results in never attempting to store files over directories
79 * or directories over files; key/value stores allow this but filesystems do not
80 * - f) Use ASCII file names (e.g. base32, IDs, hashes) to avoid Unicode issues in Windows
81 * - g) Do not assume that move operations are atomic (difficult with key/value stores)
82 * - h) Do not assume that file stat or read operations always have immediate consistency;
83 * various methods have a "latest" flag that should always be used if up-to-date
84 * information is required (this trades performance for correctness as needed)
85 * - i) Do not assume that directory listings have immediate consistency
87 * Methods of subclasses should avoid throwing exceptions at all costs.
88 * As a corollary, external dependencies should be kept to a minimum.
90 * @ingroup FileBackend
93 abstract class FileBackend
implements LoggerAwareInterface
{
94 /** @var string Unique backend name */
97 /** @var string Unique domain name */
100 /** @var string Read-only explanation message */
103 /** @var string When to do operations in parallel */
104 protected $parallelize;
106 /** @var int How many operations can be done in parallel */
107 protected $concurrency;
109 /** @var string Temporary file directory */
110 protected $tmpDirectory;
112 /** @var LockManager */
113 protected $lockManager;
114 /** @var FileJournal */
115 protected $fileJournal;
116 /** @var LoggerInterface */
118 /** @var callable|null */
122 protected $obResetFunc;
124 protected $streamMimeFunc;
126 protected $statusWrapper;
128 /** Bitfield flags for supported features */
129 const ATTR_HEADERS
= 1; // files can be tagged with standard HTTP headers
130 const ATTR_METADATA
= 2; // files can be stored with metadata key/values
131 const ATTR_UNICODE_PATHS
= 4; // files can have Unicode paths (not just ASCII)
134 * Create a new backend instance from configuration.
135 * This should only be called from within FileBackendGroup.
137 * @param array $config Parameters include:
138 * - name : The unique name of this backend.
139 * This should consist of alphanumberic, '-', and '_' characters.
140 * This name should not be changed after use (e.g. with journaling).
141 * Note that the name is *not* used in actual container names.
142 * - domainId : Prefix to container names that is unique to this backend.
143 * It should only consist of alphanumberic, '-', and '_' characters.
144 * This ID is what avoids collisions if multiple logical backends
145 * use the same storage system, so this should be set carefully.
146 * - lockManager : LockManager object to use for any file locking.
147 * If not provided, then no file locking will be enforced.
148 * - fileJournal : FileJournal object to use for logging changes to files.
149 * If not provided, then change journaling will be disabled.
150 * - readOnly : Write operations are disallowed if this is a non-empty string.
151 * It should be an explanation for the backend being read-only.
152 * - parallelize : When to do file operations in parallel (when possible).
153 * Allowed values are "implicit", "explicit" and "off".
154 * - concurrency : How many file operations can be done in parallel.
155 * - tmpDirectory : Directory to use for temporary files. If this is not set or null,
156 * then the backend will try to discover a usable temporary directory.
157 * - obResetFunc : alternative callback to clear the output buffer
158 * - streamMimeFunc : alternative method to determine the content type from the path
159 * - logger : Optional PSR logger object.
160 * - profiler : Optional callback that takes a section name argument and returns
161 * a ScopedCallback instance that ends the profile section in its destructor.
162 * @throws InvalidArgumentException
164 public function __construct( array $config ) {
165 $this->name
= $config['name'];
166 $this->domainId
= $config['domainId'] // e.g. "my_wiki-en_"
167 ??
$config['wikiId']; // b/c alias
168 if ( !preg_match( '!^[a-zA-Z0-9-_]{1,255}$!', $this->name
) ) {
169 throw new InvalidArgumentException( "Backend name '{$this->name}' is invalid." );
170 } elseif ( !is_string( $this->domainId
) ) {
171 throw new InvalidArgumentException(
172 "Backend domain ID not provided for '{$this->name}'." );
174 $this->lockManager
= $config['lockManager'] ??
new NullLockManager( [] );
175 $this->fileJournal
= $config['fileJournal']
176 ?? FileJournal
::factory( [ 'class' => NullFileJournal
::class ], $this->name
);
177 $this->readOnly
= isset( $config['readOnly'] )
178 ?
(string)$config['readOnly']
180 $this->parallelize
= isset( $config['parallelize'] )
181 ?
(string)$config['parallelize']
183 $this->concurrency
= isset( $config['concurrency'] )
184 ?
(int)$config['concurrency']
186 $this->obResetFunc
= $config['obResetFunc'] ??
[ $this, 'resetOutputBuffer' ];
187 $this->streamMimeFunc
= $config['streamMimeFunc'] ??
null;
188 $this->statusWrapper
= $config['statusWrapper'] ??
null;
190 $this->profiler
= $config['profiler'] ??
null;
191 if ( !is_callable( $this->profiler
) ) {
192 $this->profiler
= null;
194 $this->logger
= $config['logger'] ??
new NullLogger();
195 $this->statusWrapper
= $config['statusWrapper'] ??
null;
196 $this->tmpDirectory
= $config['tmpDirectory'] ??
null;
199 public function setLogger( LoggerInterface
$logger ) {
200 $this->logger
= $logger;
204 * Get the unique backend name.
205 * We may have multiple different backends of the same type.
206 * For example, we can have two Swift backends using different proxies.
210 final public function getName() {
215 * Get the domain identifier used for this backend (possibly empty).
220 final public function getDomainId() {
221 return $this->domainId
;
225 * Alias to getDomainId()
228 * @deprecated Since 1.34 Use getDomainId()
230 final public function getWikiId() {
231 return $this->getDomainId();
235 * Check if this backend is read-only
239 final public function isReadOnly() {
240 return ( $this->readOnly
!= '' );
244 * Get an explanatory message if this backend is read-only
246 * @return string|bool Returns false if the backend is not read-only
248 final public function getReadOnlyReason() {
249 return ( $this->readOnly
!= '' ) ?
$this->readOnly
: false;
253 * Get the a bitfield of extra features supported by the backend medium
255 * @return int Bitfield of FileBackend::ATTR_* flags
258 public function getFeatures() {
259 return self
::ATTR_UNICODE_PATHS
;
263 * Check if the backend medium supports a field of extra features
265 * @param int $bitfield Bitfield of FileBackend::ATTR_* flags
269 final public function hasFeatures( $bitfield ) {
270 return ( $this->getFeatures() & $bitfield ) === $bitfield;
274 * This is the main entry point into the backend for write operations.
275 * Callers supply an ordered list of operations to perform as a transaction.
276 * Files will be locked, the stat cache cleared, and then the operations attempted.
277 * If any serious errors occur, all attempted operations will be rolled back.
279 * $ops is an array of arrays. The outer array holds a list of operations.
280 * Each inner array is a set of key value pairs that specify an operation.
282 * Supported operations and their parameters. The supported actions are:
288 * - describe (since 1.21)
291 * FSFile/TempFSFile object support was added in 1.27.
293 * a) Create a new file in storage with the contents of a string
297 * 'dst' => <storage path>,
298 * 'content' => <string of new file contents>,
299 * 'overwrite' => <boolean>,
300 * 'overwriteSame' => <boolean>,
301 * 'headers' => <HTTP header name/value map> # since 1.21
305 * b) Copy a file system file into storage
309 * 'src' => <file system path, FSFile, or TempFSFile>,
310 * 'dst' => <storage path>,
311 * 'overwrite' => <boolean>,
312 * 'overwriteSame' => <boolean>,
313 * 'headers' => <HTTP header name/value map> # since 1.21
317 * c) Copy a file within storage
321 * 'src' => <storage path>,
322 * 'dst' => <storage path>,
323 * 'overwrite' => <boolean>,
324 * 'overwriteSame' => <boolean>,
325 * 'ignoreMissingSource' => <boolean>, # since 1.21
326 * 'headers' => <HTTP header name/value map> # since 1.21
330 * d) Move a file within storage
334 * 'src' => <storage path>,
335 * 'dst' => <storage path>,
336 * 'overwrite' => <boolean>,
337 * 'overwriteSame' => <boolean>,
338 * 'ignoreMissingSource' => <boolean>, # since 1.21
339 * 'headers' => <HTTP header name/value map> # since 1.21
343 * e) Delete a file within storage
347 * 'src' => <storage path>,
348 * 'ignoreMissingSource' => <boolean>
352 * f) Update metadata for a file within storage
355 * 'op' => 'describe',
356 * 'src' => <storage path>,
357 * 'headers' => <HTTP header name/value map>
361 * g) Do nothing (no-op)
368 * Boolean flags for operations (operation-specific):
369 * - ignoreMissingSource : The operation will simply succeed and do
370 * nothing if the source file does not exist.
371 * - overwrite : Any destination file will be overwritten.
372 * - overwriteSame : If a file already exists at the destination with the
373 * same contents, then do nothing to the destination file
374 * instead of giving an error. This does not compare headers.
375 * This option is ignored if 'overwrite' is already provided.
376 * - headers : If supplied, the result of merging these headers with any
377 * existing source file headers (replacing conflicting ones)
378 * will be set as the destination file headers. Headers are
379 * deleted if their value is set to the empty string. When a
380 * file has headers they are included in responses to GET and
381 * HEAD requests to the backing store for that file.
382 * Header values should be no larger than 255 bytes, except for
383 * Content-Disposition. The system might ignore or truncate any
384 * headers that are too long to store (exact limits will vary).
385 * Backends that don't support metadata ignore this. (since 1.21)
387 * $opts is an associative of boolean flags, including:
388 * - force : Operation precondition errors no longer trigger an abort.
389 * Any remaining operations are still attempted. Unexpected
390 * failures may still cause remaining operations to be aborted.
391 * - nonLocking : No locks are acquired for the operations.
392 * This can increase performance for non-critical writes.
393 * This has no effect unless the 'force' flag is set.
394 * - nonJournaled : Don't log this operation batch in the file journal.
395 * This limits the ability of recovery scripts.
396 * - parallelize : Try to do operations in parallel when possible.
397 * - bypassReadOnly : Allow writes in read-only mode. (since 1.20)
398 * - preserveCache : Don't clear the process cache before checking files.
399 * This should only be used if all entries in the process
400 * cache were added after the files were already locked. (since 1.20)
402 * @note Remarks on locking:
403 * File system paths given to operations should refer to files that are
404 * already locked or otherwise safe from modification from other processes.
405 * Normally these files will be new temp files, which should be adequate.
409 * This returns a Status, which contains all warnings and fatals that occurred
410 * during the operation. The 'failCount', 'successCount', and 'success' members
411 * will reflect each operation attempted.
413 * The StatusValue will be "OK" unless:
414 * - a) unexpected operation errors occurred (network partitions, disk full...)
415 * - b) significant operation errors occurred and 'force' was not set
417 * @param array $ops List of operations to execute in order
418 * @param array $opts Batch operation options
419 * @return StatusValue
421 final public function doOperations( array $ops, array $opts = [] ) {
422 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
423 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
426 return $this->newStatus(); // nothing to do
429 $ops = $this->resolveFSFileObjects( $ops );
430 if ( empty( $opts['force'] ) ) { // sanity
431 unset( $opts['nonLocking'] );
434 /** @noinspection PhpUnusedLocalVariableInspection */
435 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
437 return $this->doOperationsInternal( $ops, $opts );
441 * @see FileBackend::doOperations()
444 * @return StatusValue
446 abstract protected function doOperationsInternal( array $ops, array $opts );
449 * Same as doOperations() except it takes a single operation.
450 * If you are doing a batch of operations that should either
451 * all succeed or all fail, then use that function instead.
453 * @see FileBackend::doOperations()
455 * @param array $op Operation
456 * @param array $opts Operation options
457 * @return StatusValue
459 final public function doOperation( array $op, array $opts = [] ) {
460 return $this->doOperations( [ $op ], $opts );
464 * Performs a single create operation.
465 * This sets $params['op'] to 'create' and passes it to doOperation().
467 * @see FileBackend::doOperation()
469 * @param array $params Operation parameters
470 * @param array $opts Operation options
471 * @return StatusValue
473 final public function create( array $params, array $opts = [] ) {
474 return $this->doOperation( [ 'op' => 'create' ] +
$params, $opts );
478 * Performs a single store operation.
479 * This sets $params['op'] to 'store' and passes it to doOperation().
481 * @see FileBackend::doOperation()
483 * @param array $params Operation parameters
484 * @param array $opts Operation options
485 * @return StatusValue
487 final public function store( array $params, array $opts = [] ) {
488 return $this->doOperation( [ 'op' => 'store' ] +
$params, $opts );
492 * Performs a single copy operation.
493 * This sets $params['op'] to 'copy' and passes it to doOperation().
495 * @see FileBackend::doOperation()
497 * @param array $params Operation parameters
498 * @param array $opts Operation options
499 * @return StatusValue
501 final public function copy( array $params, array $opts = [] ) {
502 return $this->doOperation( [ 'op' => 'copy' ] +
$params, $opts );
506 * Performs a single move operation.
507 * This sets $params['op'] to 'move' and passes it to doOperation().
509 * @see FileBackend::doOperation()
511 * @param array $params Operation parameters
512 * @param array $opts Operation options
513 * @return StatusValue
515 final public function move( array $params, array $opts = [] ) {
516 return $this->doOperation( [ 'op' => 'move' ] +
$params, $opts );
520 * Performs a single delete operation.
521 * This sets $params['op'] to 'delete' and passes it to doOperation().
523 * @see FileBackend::doOperation()
525 * @param array $params Operation parameters
526 * @param array $opts Operation options
527 * @return StatusValue
529 final public function delete( array $params, array $opts = [] ) {
530 return $this->doOperation( [ 'op' => 'delete' ] +
$params, $opts );
534 * Performs a single describe operation.
535 * This sets $params['op'] to 'describe' and passes it to doOperation().
537 * @see FileBackend::doOperation()
539 * @param array $params Operation parameters
540 * @param array $opts Operation options
541 * @return StatusValue
544 final public function describe( array $params, array $opts = [] ) {
545 return $this->doOperation( [ 'op' => 'describe' ] +
$params, $opts );
549 * Perform a set of independent file operations on some files.
551 * This does no locking, nor journaling, and possibly no stat calls.
552 * Any destination files that already exist will be overwritten.
553 * This should *only* be used on non-original files, like cache files.
555 * Supported operations and their parameters:
561 * - describe (since 1.21)
564 * FSFile/TempFSFile object support was added in 1.27.
566 * a) Create a new file in storage with the contents of a string
570 * 'dst' => <storage path>,
571 * 'content' => <string of new file contents>,
572 * 'headers' => <HTTP header name/value map> # since 1.21
576 * b) Copy a file system file into storage
580 * 'src' => <file system path, FSFile, or TempFSFile>,
581 * 'dst' => <storage path>,
582 * 'headers' => <HTTP header name/value map> # since 1.21
586 * c) Copy a file within storage
590 * 'src' => <storage path>,
591 * 'dst' => <storage path>,
592 * 'ignoreMissingSource' => <boolean>, # since 1.21
593 * 'headers' => <HTTP header name/value map> # since 1.21
597 * d) Move a file within storage
601 * 'src' => <storage path>,
602 * 'dst' => <storage path>,
603 * 'ignoreMissingSource' => <boolean>, # since 1.21
604 * 'headers' => <HTTP header name/value map> # since 1.21
608 * e) Delete a file within storage
612 * 'src' => <storage path>,
613 * 'ignoreMissingSource' => <boolean>
617 * f) Update metadata for a file within storage
620 * 'op' => 'describe',
621 * 'src' => <storage path>,
622 * 'headers' => <HTTP header name/value map>
626 * g) Do nothing (no-op)
633 * @par Boolean flags for operations (operation-specific):
634 * - ignoreMissingSource : The operation will simply succeed and do
635 * nothing if the source file does not exist.
636 * - headers : If supplied with a header name/value map, the backend will
637 * reply with these headers when GETs/HEADs of the destination
638 * file are made. Header values should be smaller than 256 bytes.
639 * Content-Disposition headers can be longer, though the system
640 * might ignore or truncate ones that are too long to store.
641 * Existing headers will remain, but these will replace any
642 * conflicting previous headers, and headers will be removed
643 * if they are set to an empty string.
644 * Backends that don't support metadata ignore this. (since 1.21)
646 * $opts is an associative of boolean flags, including:
647 * - bypassReadOnly : Allow writes in read-only mode (since 1.20)
650 * This returns a Status, which contains all warnings and fatals that occurred
651 * during the operation. The 'failCount', 'successCount', and 'success' members
652 * will reflect each operation attempted for the given files. The StatusValue will be
653 * considered "OK" as long as no fatal errors occurred.
655 * @param array $ops Set of operations to execute
656 * @param array $opts Batch operation options
657 * @return StatusValue
660 final public function doQuickOperations( array $ops, array $opts = [] ) {
661 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
662 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
665 return $this->newStatus(); // nothing to do
668 $ops = $this->resolveFSFileObjects( $ops );
669 foreach ( $ops as &$op ) {
670 $op['overwrite'] = true; // avoids RTTs in key/value stores
673 /** @noinspection PhpUnusedLocalVariableInspection */
674 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
676 return $this->doQuickOperationsInternal( $ops );
680 * @see FileBackend::doQuickOperations()
682 * @return StatusValue
685 abstract protected function doQuickOperationsInternal( array $ops );
688 * Same as doQuickOperations() except it takes a single operation.
689 * If you are doing a batch of operations, then use that function instead.
691 * @see FileBackend::doQuickOperations()
693 * @param array $op Operation
694 * @return StatusValue
697 final public function doQuickOperation( array $op ) {
698 return $this->doQuickOperations( [ $op ] );
702 * Performs a single quick create operation.
703 * This sets $params['op'] to 'create' and passes it to doQuickOperation().
705 * @see FileBackend::doQuickOperation()
707 * @param array $params Operation parameters
708 * @return StatusValue
711 final public function quickCreate( array $params ) {
712 return $this->doQuickOperation( [ 'op' => 'create' ] +
$params );
716 * Performs a single quick store operation.
717 * This sets $params['op'] to 'store' and passes it to doQuickOperation().
719 * @see FileBackend::doQuickOperation()
721 * @param array $params Operation parameters
722 * @return StatusValue
725 final public function quickStore( array $params ) {
726 return $this->doQuickOperation( [ 'op' => 'store' ] +
$params );
730 * Performs a single quick copy operation.
731 * This sets $params['op'] to 'copy' and passes it to doQuickOperation().
733 * @see FileBackend::doQuickOperation()
735 * @param array $params Operation parameters
736 * @return StatusValue
739 final public function quickCopy( array $params ) {
740 return $this->doQuickOperation( [ 'op' => 'copy' ] +
$params );
744 * Performs a single quick move operation.
745 * This sets $params['op'] to 'move' and passes it to doQuickOperation().
747 * @see FileBackend::doQuickOperation()
749 * @param array $params Operation parameters
750 * @return StatusValue
753 final public function quickMove( array $params ) {
754 return $this->doQuickOperation( [ 'op' => 'move' ] +
$params );
758 * Performs a single quick delete operation.
759 * This sets $params['op'] to 'delete' and passes it to doQuickOperation().
761 * @see FileBackend::doQuickOperation()
763 * @param array $params Operation parameters
764 * @return StatusValue
767 final public function quickDelete( array $params ) {
768 return $this->doQuickOperation( [ 'op' => 'delete' ] +
$params );
772 * Performs a single quick describe operation.
773 * This sets $params['op'] to 'describe' and passes it to doQuickOperation().
775 * @see FileBackend::doQuickOperation()
777 * @param array $params Operation parameters
778 * @return StatusValue
781 final public function quickDescribe( array $params ) {
782 return $this->doQuickOperation( [ 'op' => 'describe' ] +
$params );
786 * Concatenate a list of storage files into a single file system file.
787 * The target path should refer to a file that is already locked or
788 * otherwise safe from modification from other processes. Normally,
789 * the file will be a new temp file, which should be adequate.
791 * @param array $params Operation parameters, include:
792 * - srcs : ordered source storage paths (e.g. chunk1, chunk2, ...)
793 * - dst : file system path to 0-byte temp file
794 * - parallelize : try to do operations in parallel when possible
795 * @return StatusValue
797 abstract public function concatenate( array $params );
800 * Prepare a storage directory for usage.
801 * This will create any required containers and parent directories.
802 * Backends using key/value stores only need to create the container.
804 * The 'noAccess' and 'noListing' parameters works the same as in secure(),
805 * except they are only applied *if* the directory/container had to be created.
806 * These flags should always be set for directories that have private files.
807 * However, setting them is not guaranteed to actually do anything.
808 * Additional server configuration may be needed to achieve the desired effect.
810 * @param array $params Parameters include:
811 * - dir : storage directory
812 * - noAccess : try to deny file access (since 1.20)
813 * - noListing : try to deny file listing (since 1.20)
814 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
815 * @return StatusValue
817 final public function prepare( array $params ) {
818 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
819 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
821 /** @noinspection PhpUnusedLocalVariableInspection */
822 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
823 return $this->doPrepare( $params );
827 * @see FileBackend::prepare()
828 * @param array $params
829 * @return StatusValue
831 abstract protected function doPrepare( array $params );
834 * Take measures to block web access to a storage directory and
835 * the container it belongs to. FS backends might add .htaccess
836 * files whereas key/value store backends might revoke container
837 * access to the storage user representing end-users in web requests.
839 * This is not guaranteed to actually make files or listings publicly hidden.
840 * Additional server configuration may be needed to achieve the desired effect.
842 * @param array $params Parameters include:
843 * - dir : storage directory
844 * - noAccess : try to deny file access
845 * - noListing : try to deny file listing
846 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
847 * @return StatusValue
849 final public function secure( array $params ) {
850 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
851 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
853 /** @noinspection PhpUnusedLocalVariableInspection */
854 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
855 return $this->doSecure( $params );
859 * @see FileBackend::secure()
860 * @param array $params
861 * @return StatusValue
863 abstract protected function doSecure( array $params );
866 * Remove measures to block web access to a storage directory and
867 * the container it belongs to. FS backends might remove .htaccess
868 * files whereas key/value store backends might grant container
869 * access to the storage user representing end-users in web requests.
870 * This essentially can undo the result of secure() calls.
872 * This is not guaranteed to actually make files or listings publicly viewable.
873 * Additional server configuration may be needed to achieve the desired effect.
875 * @param array $params Parameters include:
876 * - dir : storage directory
877 * - access : try to allow file access
878 * - listing : try to allow file listing
879 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
880 * @return StatusValue
883 final public function publish( array $params ) {
884 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
885 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
887 /** @noinspection PhpUnusedLocalVariableInspection */
888 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
889 return $this->doPublish( $params );
893 * @see FileBackend::publish()
894 * @param array $params
895 * @return StatusValue
897 abstract protected function doPublish( array $params );
900 * Delete a storage directory if it is empty.
901 * Backends using key/value stores may do nothing unless the directory
902 * is that of an empty container, in which case it will be deleted.
904 * @param array $params Parameters include:
905 * - dir : storage directory
906 * - recursive : recursively delete empty subdirectories first (since 1.20)
907 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
908 * @return StatusValue
910 final public function clean( array $params ) {
911 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
912 return $this->newStatus( 'backend-fail-readonly', $this->name
, $this->readOnly
);
914 /** @noinspection PhpUnusedLocalVariableInspection */
915 $scope = ScopedCallback
::newScopedIgnoreUserAbort(); // try to ignore client aborts
916 return $this->doClean( $params );
920 * @see FileBackend::clean()
921 * @param array $params
922 * @return StatusValue
924 abstract protected function doClean( array $params );
927 * Check if a file exists at a storage path in the backend.
928 * This returns false if only a directory exists at the path.
930 * @param array $params Parameters include:
931 * - src : source storage path
932 * - latest : use the latest available data
933 * @return bool|null Returns null on failure
935 abstract public function fileExists( array $params );
938 * Get the last-modified timestamp of the file at a storage path.
940 * @param array $params Parameters include:
941 * - src : source storage path
942 * - latest : use the latest available data
943 * @return string|bool TS_MW timestamp or false on failure
945 abstract public function getFileTimestamp( array $params );
948 * Get the contents of a file at a storage path in the backend.
949 * This should be avoided for potentially large files.
951 * @param array $params Parameters include:
952 * - src : source storage path
953 * - latest : use the latest available data
954 * @return string|bool Returns false on failure
956 final public function getFileContents( array $params ) {
957 $contents = $this->getFileContentsMulti(
958 [ 'srcs' => [ $params['src'] ] ] +
$params );
960 return $contents[$params['src']];
964 * Like getFileContents() except it takes an array of storage paths
965 * and returns a map of storage paths to strings (or null on failure).
966 * The map keys (paths) are in the same order as the provided list of paths.
968 * @see FileBackend::getFileContents()
970 * @param array $params Parameters include:
971 * - srcs : list of source storage paths
972 * - latest : use the latest available data
973 * - parallelize : try to do operations in parallel when possible
974 * @return array Map of (path name => string or false on failure)
977 abstract public function getFileContentsMulti( array $params );
980 * Get metadata about a file at a storage path in the backend.
981 * If the file does not exist, then this returns false.
982 * Otherwise, the result is an associative array that includes:
983 * - headers : map of HTTP headers used for GET/HEAD requests (name => value)
984 * - metadata : map of file metadata (name => value)
985 * Metadata keys and headers names will be returned in all lower-case.
986 * Additional values may be included for internal use only.
988 * Use FileBackend::hasFeatures() to check how well this is supported.
990 * @param array $params
992 * - src : source storage path
993 * - latest : use the latest available data
994 * @return array|bool Returns false on failure
997 abstract public function getFileXAttributes( array $params );
1000 * Get the size (bytes) of a file at a storage path in the backend.
1002 * @param array $params Parameters include:
1003 * - src : source storage path
1004 * - latest : use the latest available data
1005 * @return int|bool Returns false on failure
1007 abstract public function getFileSize( array $params );
1010 * Get quick information about a file at a storage path in the backend.
1011 * If the file does not exist, then this returns false.
1012 * Otherwise, the result is an associative array that includes:
1013 * - mtime : the last-modified timestamp (TS_MW)
1014 * - size : the file size (bytes)
1015 * Additional values may be included for internal use only.
1017 * @param array $params Parameters include:
1018 * - src : source storage path
1019 * - latest : use the latest available data
1020 * @return array|bool|null Returns null on failure
1022 abstract public function getFileStat( array $params );
1025 * Get a SHA-1 hash of the file at a storage path in the backend.
1027 * @param array $params Parameters include:
1028 * - src : source storage path
1029 * - latest : use the latest available data
1030 * @return string|bool Hash string or false on failure
1032 abstract public function getFileSha1Base36( array $params );
1035 * Get the properties of the file at a storage path in the backend.
1036 * This gives the result of FSFile::getProps() on a local copy of the file.
1038 * @param array $params Parameters include:
1039 * - src : source storage path
1040 * - latest : use the latest available data
1041 * @return array Returns FSFile::placeholderProps() on failure
1043 abstract public function getFileProps( array $params );
1046 * Stream the file at a storage path in the backend.
1048 * If the file does not exists, an HTTP 404 error will be given.
1049 * Appropriate HTTP headers (Status, Content-Type, Content-Length)
1050 * will be sent if streaming began, while none will be sent otherwise.
1051 * Implementations should flush the output buffer before sending data.
1053 * @param array $params Parameters include:
1054 * - src : source storage path
1055 * - headers : list of additional HTTP headers to send if the file exists
1056 * - options : HTTP request header map with lower case keys (since 1.28). Supports:
1057 * range : format is "bytes=(\d*-\d*)"
1058 * if-modified-since : format is an HTTP date
1059 * - headless : only include the body (and headers from "headers") (since 1.28)
1060 * - latest : use the latest available data
1061 * - allowOB : preserve any output buffers (since 1.28)
1062 * @return StatusValue
1064 abstract public function streamFile( array $params );
1067 * Returns a file system file, identical to the file at a storage path.
1068 * The file returned is either:
1069 * - a) A local copy of the file at a storage path in the backend.
1070 * The temporary copy will have the same extension as the source.
1071 * - b) An original of the file at a storage path in the backend.
1072 * Temporary files may be purged when the file object falls out of scope.
1074 * Write operations should *never* be done on this file as some backends
1075 * may do internal tracking or may be instances of FileBackendMultiWrite.
1076 * In that latter case, there are copies of the file that must stay in sync.
1077 * Additionally, further calls to this function may return the same file.
1079 * @param array $params Parameters include:
1080 * - src : source storage path
1081 * - latest : use the latest available data
1082 * @return FSFile|null Returns null on failure
1084 final public function getLocalReference( array $params ) {
1085 $fsFiles = $this->getLocalReferenceMulti(
1086 [ 'srcs' => [ $params['src'] ] ] +
$params );
1088 return $fsFiles[$params['src']];
1092 * Like getLocalReference() except it takes an array of storage paths
1093 * and returns a map of storage paths to FSFile objects (or null on failure).
1094 * The map keys (paths) are in the same order as the provided list of paths.
1096 * @see FileBackend::getLocalReference()
1098 * @param array $params Parameters include:
1099 * - srcs : list of source storage paths
1100 * - latest : use the latest available data
1101 * - parallelize : try to do operations in parallel when possible
1102 * @return array Map of (path name => FSFile or null on failure)
1105 abstract public function getLocalReferenceMulti( array $params );
1108 * Get a local copy on disk of the file at a storage path in the backend.
1109 * The temporary copy will have the same file extension as the source.
1110 * Temporary files may be purged when the file object falls out of scope.
1112 * @param array $params Parameters include:
1113 * - src : source storage path
1114 * - latest : use the latest available data
1115 * @return TempFSFile|null Returns null on failure
1117 final public function getLocalCopy( array $params ) {
1118 $tmpFiles = $this->getLocalCopyMulti(
1119 [ 'srcs' => [ $params['src'] ] ] +
$params );
1121 return $tmpFiles[$params['src']];
1125 * Like getLocalCopy() except it takes an array of storage paths and
1126 * returns a map of storage paths to TempFSFile objects (or null on failure).
1127 * The map keys (paths) are in the same order as the provided list of paths.
1129 * @see FileBackend::getLocalCopy()
1131 * @param array $params Parameters include:
1132 * - srcs : list of source storage paths
1133 * - latest : use the latest available data
1134 * - parallelize : try to do operations in parallel when possible
1135 * @return array Map of (path name => TempFSFile or null on failure)
1138 abstract public function getLocalCopyMulti( array $params );
1141 * Return an HTTP URL to a given file that requires no authentication to use.
1142 * The URL may be pre-authenticated (via some token in the URL) and temporary.
1143 * This will return null if the backend cannot make an HTTP URL for the file.
1145 * This is useful for key/value stores when using scripts that seek around
1146 * large files and those scripts (and the backend) support HTTP Range headers.
1147 * Otherwise, one would need to use getLocalReference(), which involves loading
1148 * the entire file on to local disk.
1150 * @param array $params Parameters include:
1151 * - src : source storage path
1152 * - ttl : lifetime (seconds) if pre-authenticated; default is 1 day
1153 * @return string|null
1156 abstract public function getFileHttpUrl( array $params );
1159 * Check if a directory exists at a given storage path.
1160 * Backends using key/value stores will check if the path is a
1161 * virtual directory, meaning there are files under the given directory.
1163 * Storage backends with eventual consistency might return stale data.
1165 * @param array $params Parameters include:
1166 * - dir : storage directory
1167 * @return bool|null Returns null on failure
1170 abstract public function directoryExists( array $params );
1173 * Get an iterator to list *all* directories under a storage directory.
1174 * If the directory is of the form "mwstore://backend/container",
1175 * then all directories in the container will be listed.
1176 * If the directory is of form "mwstore://backend/container/dir",
1177 * then all directories directly under that directory will be listed.
1178 * Results will be storage directories relative to the given directory.
1180 * Storage backends with eventual consistency might return stale data.
1182 * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1184 * @param array $params Parameters include:
1185 * - dir : storage directory
1186 * - topOnly : only return direct child dirs of the directory
1187 * @return Traversable|array|null Returns null on failure
1190 abstract public function getDirectoryList( array $params );
1193 * Same as FileBackend::getDirectoryList() except only lists
1194 * directories that are immediately under the given directory.
1196 * Storage backends with eventual consistency might return stale data.
1198 * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1200 * @param array $params Parameters include:
1201 * - dir : storage directory
1202 * @return Traversable|array|null Returns null on failure
1205 final public function getTopDirectoryList( array $params ) {
1206 return $this->getDirectoryList( [ 'topOnly' => true ] +
$params );
1210 * Get an iterator to list *all* stored files under a storage directory.
1211 * If the directory is of the form "mwstore://backend/container",
1212 * then all files in the container will be listed.
1213 * If the directory is of form "mwstore://backend/container/dir",
1214 * then all files under that directory will be listed.
1215 * Results will be storage paths relative to the given directory.
1217 * Storage backends with eventual consistency might return stale data.
1219 * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1221 * @param array $params Parameters include:
1222 * - dir : storage directory
1223 * - topOnly : only return direct child files of the directory (since 1.20)
1224 * - adviseStat : set to true if stat requests will be made on the files (since 1.22)
1225 * @return Traversable|array|null Returns null on failure
1227 abstract public function getFileList( array $params );
1230 * Same as FileBackend::getFileList() except only lists
1231 * files that are immediately under the given directory.
1233 * Storage backends with eventual consistency might return stale data.
1235 * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1237 * @param array $params Parameters include:
1238 * - dir : storage directory
1239 * - adviseStat : set to true if stat requests will be made on the files (since 1.22)
1240 * @return Traversable|array|null Returns null on failure
1243 final public function getTopFileList( array $params ) {
1244 return $this->getFileList( [ 'topOnly' => true ] +
$params );
1248 * Preload persistent file stat cache and property cache into in-process cache.
1249 * This should be used when stat calls will be made on a known list of a many files.
1251 * @see FileBackend::getFileStat()
1253 * @param array $paths Storage paths
1255 abstract public function preloadCache( array $paths );
1258 * Invalidate any in-process file stat and property cache.
1259 * If $paths is given, then only the cache for those files will be cleared.
1261 * @see FileBackend::getFileStat()
1263 * @param array|null $paths Storage paths (optional)
1265 abstract public function clearCache( array $paths = null );
1268 * Preload file stat information (concurrently if possible) into in-process cache.
1270 * This should be used when stat calls will be made on a known list of a many files.
1271 * This does not make use of the persistent file stat cache.
1273 * @see FileBackend::getFileStat()
1275 * @param array $params Parameters include:
1276 * - srcs : list of source storage paths
1277 * - latest : use the latest available data
1278 * @return bool All requests proceeded without I/O errors (since 1.24)
1281 abstract public function preloadFileStat( array $params );
1284 * Lock the files at the given storage paths in the backend.
1285 * This will either lock all the files or none (on failure).
1287 * Callers should consider using getScopedFileLocks() instead.
1289 * @param array $paths Storage paths
1290 * @param int $type LockManager::LOCK_* constant
1291 * @param int $timeout Timeout in seconds (0 means non-blocking) (since 1.24)
1292 * @return StatusValue
1294 final public function lockFiles( array $paths, $type, $timeout = 0 ) {
1295 $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1297 return $this->wrapStatus( $this->lockManager
->lock( $paths, $type, $timeout ) );
1301 * Unlock the files at the given storage paths in the backend.
1303 * @param array $paths Storage paths
1304 * @param int $type LockManager::LOCK_* constant
1305 * @return StatusValue
1307 final public function unlockFiles( array $paths, $type ) {
1308 $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1310 return $this->wrapStatus( $this->lockManager
->unlock( $paths, $type ) );
1314 * Lock the files at the given storage paths in the backend.
1315 * This will either lock all the files or none (on failure).
1316 * On failure, the StatusValue object will be updated with errors.
1318 * Once the return value goes out scope, the locks will be released and
1319 * the StatusValue updated. Unlock fatals will not change the StatusValue "OK" value.
1321 * @see ScopedLock::factory()
1323 * @param array $paths List of storage paths or map of lock types to path lists
1324 * @param int|string $type LockManager::LOCK_* constant or "mixed"
1325 * @param StatusValue $status StatusValue to update on lock/unlock
1326 * @param int $timeout Timeout in seconds (0 means non-blocking) (since 1.24)
1327 * @return ScopedLock|null Returns null on failure
1329 final public function getScopedFileLocks(
1330 array $paths, $type, StatusValue
$status, $timeout = 0
1332 if ( $type === 'mixed' ) {
1333 foreach ( $paths as &$typePaths ) {
1334 $typePaths = array_map( 'FileBackend::normalizeStoragePath', $typePaths );
1337 $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1340 return ScopedLock
::factory( $this->lockManager
, $paths, $type, $status, $timeout );
1344 * Get an array of scoped locks needed for a batch of file operations.
1346 * Normally, FileBackend::doOperations() handles locking, unless
1347 * the 'nonLocking' param is passed in. This function is useful if you
1348 * want the files to be locked for a broader scope than just when the
1349 * files are changing. For example, if you need to update DB metadata,
1350 * you may want to keep the files locked until finished.
1352 * @see FileBackend::doOperations()
1354 * @param array $ops List of file operations to FileBackend::doOperations()
1355 * @param StatusValue $status StatusValue to update on lock/unlock
1356 * @return ScopedLock|null
1359 abstract public function getScopedLocksForOps( array $ops, StatusValue
$status );
1362 * Get the root storage path of this backend.
1363 * All container paths are "subdirectories" of this path.
1365 * @return string Storage path
1368 final public function getRootStoragePath() {
1369 return "mwstore://{$this->name}";
1373 * Get the storage path for the given container for this backend
1375 * @param string $container Container name
1376 * @return string Storage path
1379 final public function getContainerStoragePath( $container ) {
1380 return $this->getRootStoragePath() . "/{$container}";
1384 * Get the file journal object for this backend
1386 * @return FileJournal
1388 final public function getJournal() {
1389 return $this->fileJournal
;
1393 * Convert FSFile 'src' paths to string paths (with an 'srcRef' field set to the FSFile)
1395 * The 'srcRef' field keeps any TempFSFile objects in scope for the backend to have it
1396 * around as long it needs (which may vary greatly depending on configuration)
1398 * @param array $ops File operation batch for FileBaclend::doOperations()
1399 * @return array File operation batch
1401 protected function resolveFSFileObjects( array $ops ) {
1402 foreach ( $ops as &$op ) {
1403 $src = $op['src'] ??
null;
1404 if ( $src instanceof FSFile
) {
1405 $op['srcRef'] = $src;
1406 $op['src'] = $src->getPath();
1415 * Check if a given path is a "mwstore://" path.
1416 * This does not do any further validation or any existence checks.
1418 * @param string $path
1421 final public static function isStoragePath( $path ) {
1422 return ( strpos( $path, 'mwstore://' ) === 0 );
1426 * Split a storage path into a backend name, a container name,
1427 * and a relative file path. The relative path may be the empty string.
1428 * This does not do any path normalization or traversal checks.
1430 * @param string $storagePath
1431 * @return array (backend, container, rel object) or (null, null, null)
1433 final public static function splitStoragePath( $storagePath ) {
1434 if ( self
::isStoragePath( $storagePath ) ) {
1435 // Remove the "mwstore://" prefix and split the path
1436 $parts = explode( '/', substr( $storagePath, 10 ), 3 );
1437 if ( count( $parts ) >= 2 && $parts[0] != '' && $parts[1] != '' ) {
1438 if ( count( $parts ) == 3 ) {
1439 return $parts; // e.g. "backend/container/path"
1441 return [ $parts[0], $parts[1], '' ]; // e.g. "backend/container"
1446 return [ null, null, null ];
1450 * Normalize a storage path by cleaning up directory separators.
1451 * Returns null if the path is not of the format of a valid storage path.
1453 * @param string $storagePath
1454 * @return string|null
1456 final public static function normalizeStoragePath( $storagePath ) {
1457 list( $backend, $container, $relPath ) = self
::splitStoragePath( $storagePath );
1458 if ( $relPath !== null ) { // must be for this backend
1459 $relPath = self
::normalizeContainerPath( $relPath );
1460 if ( $relPath !== null ) {
1461 return ( $relPath != '' )
1462 ?
"mwstore://{$backend}/{$container}/{$relPath}"
1463 : "mwstore://{$backend}/{$container}";
1471 * Get the parent storage directory of a storage path.
1472 * This returns a path like "mwstore://backend/container",
1473 * "mwstore://backend/container/...", or null if there is no parent.
1475 * @param string $storagePath
1476 * @return string|null
1478 final public static function parentStoragePath( $storagePath ) {
1479 $storagePath = dirname( $storagePath );
1480 list( , , $rel ) = self
::splitStoragePath( $storagePath );
1482 return ( $rel === null ) ?
null : $storagePath;
1486 * Get the final extension from a storage or FS path
1488 * @param string $path
1489 * @param string $case One of (rawcase, uppercase, lowercase) (since 1.24)
1492 final public static function extensionFromPath( $path, $case = 'lowercase' ) {
1493 $i = strrpos( $path, '.' );
1494 $ext = $i ?
substr( $path, $i +
1 ) : '';
1496 if ( $case === 'lowercase' ) {
1497 $ext = strtolower( $ext );
1498 } elseif ( $case === 'uppercase' ) {
1499 $ext = strtoupper( $ext );
1506 * Check if a relative path has no directory traversals
1508 * @param string $path
1512 final public static function isPathTraversalFree( $path ) {
1513 return ( self
::normalizeContainerPath( $path ) !== null );
1517 * Build a Content-Disposition header value per RFC 6266.
1519 * @param string $type One of (attachment, inline)
1520 * @param string $filename Suggested file name (should not contain slashes)
1521 * @throws FileBackendError
1525 final public static function makeContentDisposition( $type, $filename = '' ) {
1528 $type = strtolower( $type );
1529 if ( !in_array( $type, [ 'inline', 'attachment' ] ) ) {
1530 throw new InvalidArgumentException( "Invalid Content-Disposition type '$type'." );
1534 if ( strlen( $filename ) ) {
1535 $parts[] = "filename*=UTF-8''" . rawurlencode( basename( $filename ) );
1538 return implode( ';', $parts );
1542 * Validate and normalize a relative storage path.
1543 * Null is returned if the path involves directory traversal.
1544 * Traversal is insecure for FS backends and broken for others.
1546 * This uses the same traversal protection as Title::secureAndSplit().
1548 * @param string $path Storage path relative to a container
1549 * @return string|null
1551 final protected static function normalizeContainerPath( $path ) {
1552 // Normalize directory separators
1553 $path = strtr( $path, '\\', '/' );
1554 // Collapse any consecutive directory separators
1555 $path = preg_replace( '![/]{2,}!', '/', $path );
1556 // Remove any leading directory separator
1557 $path = ltrim( $path, '/' );
1558 // Use the same traversal protection as Title::secureAndSplit()
1559 if ( strpos( $path, '.' ) !== false ) {
1563 strpos( $path, './' ) === 0 ||
1564 strpos( $path, '../' ) === 0 ||
1565 strpos( $path, '/./' ) !== false ||
1566 strpos( $path, '/../' ) !== false
1576 * Yields the result of the status wrapper callback on either:
1577 * - StatusValue::newGood() if this method is called without parameters
1578 * - StatusValue::newFatal() with all parameters to this method if passed in
1580 * @param string ...$args
1581 * @return StatusValue
1583 final protected function newStatus( ...$args ) {
1584 if ( count( $args ) ) {
1585 $sv = StatusValue
::newFatal( ...$args );
1587 $sv = StatusValue
::newGood();
1590 return $this->wrapStatus( $sv );
1594 * @param StatusValue $sv
1595 * @return StatusValue Modified status or StatusValue subclass
1597 final protected function wrapStatus( StatusValue
$sv ) {
1598 return $this->statusWrapper ?
call_user_func( $this->statusWrapper
, $sv ) : $sv;
1602 * @param string $section
1603 * @return ScopedCallback|null
1605 protected function scopedProfileSection( $section ) {
1606 return $this->profiler ?
( $this->profiler
)( $section ) : null;
1609 protected function resetOutputBuffer() {
1610 while ( ob_get_status() ) {
1611 if ( !ob_end_clean() ) {
1612 // Could not remove output buffer handler; abort now
1613 // to avoid getting in some kind of infinite loop.