includes/libs/filebackend/FileBackend.php

   1 <?php
   2 /**
   3  * @defgroup FileBackend File backend
   4  *
   5  * File backend is used to interact with file storage systems,
   6  * such as the local file system, NFS, or cloud storage systems.
   7  */
   8
   9 /**
  10  * Base class for all file backends.
  11  *
  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.
  16  *
  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.
  21  *
  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
  26  *
  27  * @file
  28  * @ingroup FileBackend
  29  * @author Aaron Schulz
  30  */
  31
  32 /**
  33  * @brief Base class for all file backend classes (including multi-write backends).
  34  *
  35  * This class defines the methods as abstract that subclasses must implement.
  36  * Outside callers can assume that all backends will have these functions.
  37  *
  38  * All "storage paths" are of the format "mwstore://<backend>/<container>/<path>".
  39  * The "backend" portion is unique name for MediaWiki to refer to a backend, while
  40  * the "container" portion is a top-level directory of the backend. The "path" portion
  41  * is a relative path that uses UNIX file system (FS) notation, though any particular
  42  * backend may not actually be using a local filesystem. Therefore, the relative paths
  43  * are only virtual.
  44  *
  45  * Backend contents are stored under wiki-specific container names by default.
  46  * Global (qualified) backends are achieved by configuring the "wiki ID" to a constant.
  47  * For legacy reasons, the FSFileBackend class allows manually setting the paths of
  48  * containers to ones that do not respect the "wiki ID".
  49  *
  50  * In key/value (object) stores, containers are the only hierarchy (the rest is emulated).
  51  * FS-based backends are somewhat more restrictive due to the existence of real
  52  * directory files; a regular file cannot have the same name as a directory. Other
  53  * backends with virtual directories may not have this limitation. Callers should
  54  * store files in such a way that no files and directories are under the same path.
  55  *
  56  * In general, this class allows for callers to access storage through the same
  57  * interface, without regard to the underlying storage system. However, calling code
  58  * must follow certain patterns and be aware of certain things to ensure compatibility:
  59  *   - a) Always call prepare() on the parent directory before trying to put a file there;
  60  *        key/value stores only need the container to exist first, but filesystems need
  61  *        all the parent directories to exist first (prepare() is aware of all this)
  62  *   - b) Always call clean() on a directory when it might become empty to avoid empty
  63  *        directory buildup on filesystems; key/value stores never have empty directories,
  64  *        so doing this helps preserve consistency in both cases
  65  *   - c) Likewise, do not rely on the existence of empty directories for anything;
  66  *        calling directoryExists() on a path that prepare() was previously called on
  67  *        will return false for key/value stores if there are no files under that path
  68  *   - d) Never alter the resulting FSFile returned from getLocalReference(), as it could
  69  *        either be a copy of the source file in /tmp or the original source file itself
  70  *   - e) Use a file layout that results in never attempting to store files over directories
  71  *        or directories over files; key/value stores allow this but filesystems do not
  72  *   - f) Use ASCII file names (e.g. base32, IDs, hashes) to avoid Unicode issues in Windows
  73  *   - g) Do not assume that move operations are atomic (difficult with key/value stores)
  74  *   - h) Do not assume that file stat or read operations always have immediate consistency;
  75  *        various methods have a "latest" flag that should always be used if up-to-date
  76  *        information is required (this trades performance for correctness as needed)
  77  *   - i) Do not assume that directory listings have immediate consistency
  78  *
  79  * Methods of subclasses should avoid throwing exceptions at all costs.
  80  * As a corollary, external dependencies should be kept to a minimum.
  81  *
  82  * @ingroup FileBackend
  83  * @since 1.19
  84  */
  85 abstract class FileBackend {
  86         /** @var string Unique backend name */
  87         protected $name;
  88
  89         /** @var string Unique wiki name */
  90         protected $wikiId;
  91
  92         /** @var string Read-only explanation message */
  93         protected $readOnly;
  94
  95         /** @var string When to do operations in parallel */
  96         protected $parallelize;
  97
  98         /** @var int How many operations can be done in parallel */
  99         protected $concurrency;
 100
 101         /** @var string Temporary file directory */
 102         protected $tmpDirectory;
 103
 104         /** @var LockManager */
 105         protected $lockManager;
 106
 107         /** @var FileJournal */
 108         protected $fileJournal;
 109
 110         /** @var callable */
 111         protected $statusWrapper;
 112
 113         /** Bitfield flags for supported features */
 114         const ATTR_HEADERS = 1; // files can be tagged with standard HTTP headers
 115         const ATTR_METADATA = 2; // files can be stored with metadata key/values
 116         const ATTR_UNICODE_PATHS = 4; // files can have Unicode paths (not just ASCII)
 117
 118         /**
 119          * Create a new backend instance from configuration.
 120          * This should only be called from within FileBackendGroup.
 121          *
 122          * @param array $config Parameters include:
 123          *   - name        : The unique name of this backend.
 124          *                   This should consist of alphanumberic, '-', and '_' characters.
 125          *                   This name should not be changed after use (e.g. with journaling).
 126          *                   Note that the name is *not* used in actual container names.
 127          *   - wikiId      : Prefix to container names that is unique to this backend.
 128          *                   It should only consist of alphanumberic, '-', and '_' characters.
 129          *                   This ID is what avoids collisions if multiple logical backends
 130          *                   use the same storage system, so this should be set carefully.
 131          *   - lockManager : LockManager object to use for any file locking.
 132          *                   If not provided, then no file locking will be enforced.
 133          *   - fileJournal : FileJournal object to use for logging changes to files.
 134          *                   If not provided, then change journaling will be disabled.
 135          *   - readOnly    : Write operations are disallowed if this is a non-empty string.
 136          *                   It should be an explanation for the backend being read-only.
 137          *   - parallelize : When to do file operations in parallel (when possible).
 138          *                   Allowed values are "implicit", "explicit" and "off".
 139          *   - concurrency : How many file operations can be done in parallel.
 140          *   - tmpDirectory : Directory to use for temporary files. If this is not set or null,
 141          *                    then the backend will try to discover a usable temporary directory.
 142          * @throws InvalidArgumentException
 143          */
 144         public function __construct( array $config ) {
 145                 $this->name = $config['name'];
 146                 $this->wikiId = $config['wikiId']; // e.g. "my_wiki-en_"
 147                 if ( !preg_match( '!^[a-zA-Z0-9-_]{1,255}$!', $this->name ) ) {
 148                         throw new InvalidArgumentException( "Backend name '{$this->name}' is invalid." );
 149                 } elseif ( !is_string( $this->wikiId ) ) {
 150                         throw new InvalidArgumentException( "Backend wiki ID not provided for '{$this->name}'." );
 151                 }
 152                 $this->lockManager = isset( $config['lockManager'] )
 153                         ? $config['lockManager']
 154                         : new NullLockManager( [] );
 155                 $this->fileJournal = isset( $config['fileJournal'] )
 156                         ? $config['fileJournal']
 157                         : FileJournal::factory( [ 'class' => 'NullFileJournal' ], $this->name );
 158                 $this->readOnly = isset( $config['readOnly'] )
 159                         ? (string)$config['readOnly']
 160                         : '';
 161                 $this->parallelize = isset( $config['parallelize'] )
 162                         ? (string)$config['parallelize']
 163                         : 'off';
 164                 $this->concurrency = isset( $config['concurrency'] )
 165                         ? (int)$config['concurrency']
 166                         : 50;
 167                 $this->statusWrapper = isset( $config['statusWrapper'] ) ? $config['statusWrapper'] : null;
 168                 $this->tmpDirectory = isset( $config['tmpDirectory'] ) ? $config['tmpDirectory'] : null;
 169         }
 170
 171         /**
 172          * Get the unique backend name.
 173          * We may have multiple different backends of the same type.
 174          * For example, we can have two Swift backends using different proxies.
 175          *
 176          * @return string
 177          */
 178         final public function getName() {
 179                 return $this->name;
 180         }
 181
 182         /**
 183          * Get the wiki identifier used for this backend (possibly empty).
 184          * Note that this might *not* be in the same format as wfWikiID().
 185          *
 186          * @return string
 187          * @since 1.20
 188          */
 189         final public function getWikiId() {
 190                 return $this->wikiId;
 191         }
 192
 193         /**
 194          * Check if this backend is read-only
 195          *
 196          * @return bool
 197          */
 198         final public function isReadOnly() {
 199                 return ( $this->readOnly != '' );
 200         }
 201
 202         /**
 203          * Get an explanatory message if this backend is read-only
 204          *
 205          * @return string|bool Returns false if the backend is not read-only
 206          */
 207         final public function getReadOnlyReason() {
 208                 return ( $this->readOnly != '' ) ? $this->readOnly : false;
 209         }
 210
 211         /**
 212          * Get the a bitfield of extra features supported by the backend medium
 213          *
 214          * @return int Bitfield of FileBackend::ATTR_* flags
 215          * @since 1.23
 216          */
 217         public function getFeatures() {
 218                 return self::ATTR_UNICODE_PATHS;
 219         }
 220
 221         /**
 222          * Check if the backend medium supports a field of extra features
 223          *
 224          * @param int $bitfield Bitfield of FileBackend::ATTR_* flags
 225          * @return bool
 226          * @since 1.23
 227          */
 228         final public function hasFeatures( $bitfield ) {
 229                 return ( $this->getFeatures() & $bitfield ) === $bitfield;
 230         }
 231
 232         /**
 233          * This is the main entry point into the backend for write operations.
 234          * Callers supply an ordered list of operations to perform as a transaction.
 235          * Files will be locked, the stat cache cleared, and then the operations attempted.
 236          * If any serious errors occur, all attempted operations will be rolled back.
 237          *
 238          * $ops is an array of arrays. The outer array holds a list of operations.
 239          * Each inner array is a set of key value pairs that specify an operation.
 240          *
 241          * Supported operations and their parameters. The supported actions are:
 242          *  - create
 243          *  - store
 244          *  - copy
 245          *  - move
 246          *  - delete
 247          *  - describe (since 1.21)
 248          *  - null
 249          *
 250          * FSFile/TempFSFile object support was added in 1.27.
 251          *
 252          * a) Create a new file in storage with the contents of a string
 253          * @code
 254          *     [
 255          *         'op'                  => 'create',
 256          *         'dst'                 => <storage path>,
 257          *         'content'             => <string of new file contents>,
 258          *         'overwrite'           => <boolean>,
 259          *         'overwriteSame'       => <boolean>,
 260          *         'headers'             => <HTTP header name/value map> # since 1.21
 261          *     ]
 262          * @endcode
 263          *
 264          * b) Copy a file system file into storage
 265          * @code
 266          *     [
 267          *         'op'                  => 'store',
 268          *         'src'                 => <file system path, FSFile, or TempFSFile>,
 269          *         'dst'                 => <storage path>,
 270          *         'overwrite'           => <boolean>,
 271          *         'overwriteSame'       => <boolean>,
 272          *         'headers'             => <HTTP header name/value map> # since 1.21
 273          *     ]
 274          * @endcode
 275          *
 276          * c) Copy a file within storage
 277          * @code
 278          *     [
 279          *         'op'                  => 'copy',
 280          *         'src'                 => <storage path>,
 281          *         'dst'                 => <storage path>,
 282          *         'overwrite'           => <boolean>,
 283          *         'overwriteSame'       => <boolean>,
 284          *         'ignoreMissingSource' => <boolean>, # since 1.21
 285          *         'headers'             => <HTTP header name/value map> # since 1.21
 286          *     ]
 287          * @endcode
 288          *
 289          * d) Move a file within storage
 290          * @code
 291          *     [
 292          *         'op'                  => 'move',
 293          *         'src'                 => <storage path>,
 294          *         'dst'                 => <storage path>,
 295          *         'overwrite'           => <boolean>,
 296          *         'overwriteSame'       => <boolean>,
 297          *         'ignoreMissingSource' => <boolean>, # since 1.21
 298          *         'headers'             => <HTTP header name/value map> # since 1.21
 299          *     ]
 300          * @endcode
 301          *
 302          * e) Delete a file within storage
 303          * @code
 304          *     [
 305          *         'op'                  => 'delete',
 306          *         'src'                 => <storage path>,
 307          *         'ignoreMissingSource' => <boolean>
 308          *     ]
 309          * @endcode
 310          *
 311          * f) Update metadata for a file within storage
 312          * @code
 313          *     [
 314          *         'op'                  => 'describe',
 315          *         'src'                 => <storage path>,
 316          *         'headers'             => <HTTP header name/value map>
 317          *     ]
 318          * @endcode
 319          *
 320          * g) Do nothing (no-op)
 321          * @code
 322          *     [
 323          *         'op'                  => 'null',
 324          *     ]
 325          * @endcode
 326          *
 327          * Boolean flags for operations (operation-specific):
 328          *   - ignoreMissingSource : The operation will simply succeed and do
 329          *                           nothing if the source file does not exist.
 330          *   - overwrite           : Any destination file will be overwritten.
 331          *   - overwriteSame       : If a file already exists at the destination with the
 332          *                           same contents, then do nothing to the destination file
 333          *                           instead of giving an error. This does not compare headers.
 334          *                           This option is ignored if 'overwrite' is already provided.
 335          *   - headers             : If supplied, the result of merging these headers with any
 336          *                           existing source file headers (replacing conflicting ones)
 337          *                           will be set as the destination file headers. Headers are
 338          *                           deleted if their value is set to the empty string. When a
 339          *                           file has headers they are included in responses to GET and
 340          *                           HEAD requests to the backing store for that file.
 341          *                           Header values should be no larger than 255 bytes, except for
 342          *                           Content-Disposition. The system might ignore or truncate any
 343          *                           headers that are too long to store (exact limits will vary).
 344          *                           Backends that don't support metadata ignore this. (since 1.21)
 345          *
 346          * $opts is an associative of boolean flags, including:
 347          *   - force               : Operation precondition errors no longer trigger an abort.
 348          *                           Any remaining operations are still attempted. Unexpected
 349          *                           failures may still cause remaining operations to be aborted.
 350          *   - nonLocking          : No locks are acquired for the operations.
 351          *                           This can increase performance for non-critical writes.
 352          *                           This has no effect unless the 'force' flag is set.
 353          *   - nonJournaled        : Don't log this operation batch in the file journal.
 354          *                           This limits the ability of recovery scripts.
 355          *   - parallelize         : Try to do operations in parallel when possible.
 356          *   - bypassReadOnly      : Allow writes in read-only mode. (since 1.20)
 357          *   - preserveCache       : Don't clear the process cache before checking files.
 358          *                           This should only be used if all entries in the process
 359          *                           cache were added after the files were already locked. (since 1.20)
 360          *
 361          * @remarks Remarks on locking:
 362          * File system paths given to operations should refer to files that are
 363          * already locked or otherwise safe from modification from other processes.
 364          * Normally these files will be new temp files, which should be adequate.
 365          *
 366          * @par Return value:
 367          *
 368          * This returns a Status, which contains all warnings and fatals that occurred
 369          * during the operation. The 'failCount', 'successCount', and 'success' members
 370          * will reflect each operation attempted.
 371          *
 372          * The StatusValue will be "OK" unless:
 373          *   - a) unexpected operation errors occurred (network partitions, disk full...)
 374          *   - b) significant operation errors occurred and 'force' was not set
 375          *
 376          * @param array $ops List of operations to execute in order
 377          * @param array $opts Batch operation options
 378          * @return StatusValue
 379          */
 380         final public function doOperations( array $ops, array $opts = [] ) {
 381                 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
 382                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 383                 }
 384                 if ( !count( $ops ) ) {
 385                         return $this->newStatus(); // nothing to do
 386                 }
 387
 388                 $ops = $this->resolveFSFileObjects( $ops );
 389                 if ( empty( $opts['force'] ) ) { // sanity
 390                         unset( $opts['nonLocking'] );
 391                 }
 392
 393                 /** @noinspection PhpUnusedLocalVariableInspection */
 394                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 395
 396                 return $this->doOperationsInternal( $ops, $opts );
 397         }
 398
 399         /**
 400          * @see FileBackend::doOperations()
 401          * @param array $ops
 402          * @param array $opts
 403          */
 404         abstract protected function doOperationsInternal( array $ops, array $opts );
 405
 406         /**
 407          * Same as doOperations() except it takes a single operation.
 408          * If you are doing a batch of operations that should either
 409          * all succeed or all fail, then use that function instead.
 410          *
 411          * @see FileBackend::doOperations()
 412          *
 413          * @param array $op Operation
 414          * @param array $opts Operation options
 415          * @return StatusValue
 416          */
 417         final public function doOperation( array $op, array $opts = [] ) {
 418                 return $this->doOperations( [ $op ], $opts );
 419         }
 420
 421         /**
 422          * Performs a single create operation.
 423          * This sets $params['op'] to 'create' and passes it to doOperation().
 424          *
 425          * @see FileBackend::doOperation()
 426          *
 427          * @param array $params Operation parameters
 428          * @param array $opts Operation options
 429          * @return StatusValue
 430          */
 431         final public function create( array $params, array $opts = [] ) {
 432                 return $this->doOperation( [ 'op' => 'create' ] + $params, $opts );
 433         }
 434
 435         /**
 436          * Performs a single store operation.
 437          * This sets $params['op'] to 'store' and passes it to doOperation().
 438          *
 439          * @see FileBackend::doOperation()
 440          *
 441          * @param array $params Operation parameters
 442          * @param array $opts Operation options
 443          * @return StatusValue
 444          */
 445         final public function store( array $params, array $opts = [] ) {
 446                 return $this->doOperation( [ 'op' => 'store' ] + $params, $opts );
 447         }
 448
 449         /**
 450          * Performs a single copy operation.
 451          * This sets $params['op'] to 'copy' and passes it to doOperation().
 452          *
 453          * @see FileBackend::doOperation()
 454          *
 455          * @param array $params Operation parameters
 456          * @param array $opts Operation options
 457          * @return StatusValue
 458          */
 459         final public function copy( array $params, array $opts = [] ) {
 460                 return $this->doOperation( [ 'op' => 'copy' ] + $params, $opts );
 461         }
 462
 463         /**
 464          * Performs a single move operation.
 465          * This sets $params['op'] to 'move' and passes it to doOperation().
 466          *
 467          * @see FileBackend::doOperation()
 468          *
 469          * @param array $params Operation parameters
 470          * @param array $opts Operation options
 471          * @return StatusValue
 472          */
 473         final public function move( array $params, array $opts = [] ) {
 474                 return $this->doOperation( [ 'op' => 'move' ] + $params, $opts );
 475         }
 476
 477         /**
 478          * Performs a single delete operation.
 479          * This sets $params['op'] to 'delete' and passes it to doOperation().
 480          *
 481          * @see FileBackend::doOperation()
 482          *
 483          * @param array $params Operation parameters
 484          * @param array $opts Operation options
 485          * @return StatusValue
 486          */
 487         final public function delete( array $params, array $opts = [] ) {
 488                 return $this->doOperation( [ 'op' => 'delete' ] + $params, $opts );
 489         }
 490
 491         /**
 492          * Performs a single describe operation.
 493          * This sets $params['op'] to 'describe' and passes it to doOperation().
 494          *
 495          * @see FileBackend::doOperation()
 496          *
 497          * @param array $params Operation parameters
 498          * @param array $opts Operation options
 499          * @return StatusValue
 500          * @since 1.21
 501          */
 502         final public function describe( array $params, array $opts = [] ) {
 503                 return $this->doOperation( [ 'op' => 'describe' ] + $params, $opts );
 504         }
 505
 506         /**
 507          * Perform a set of independent file operations on some files.
 508          *
 509          * This does no locking, nor journaling, and possibly no stat calls.
 510          * Any destination files that already exist will be overwritten.
 511          * This should *only* be used on non-original files, like cache files.
 512          *
 513          * Supported operations and their parameters:
 514          *  - create
 515          *  - store
 516          *  - copy
 517          *  - move
 518          *  - delete
 519          *  - describe (since 1.21)
 520          *  - null
 521          *
 522          * FSFile/TempFSFile object support was added in 1.27.
 523          *
 524          * a) Create a new file in storage with the contents of a string
 525          * @code
 526          *     [
 527          *         'op'                  => 'create',
 528          *         'dst'                 => <storage path>,
 529          *         'content'             => <string of new file contents>,
 530          *         'headers'             => <HTTP header name/value map> # since 1.21
 531          *     ]
 532          * @endcode
 533          *
 534          * b) Copy a file system file into storage
 535          * @code
 536          *     [
 537          *         'op'                  => 'store',
 538          *         'src'                 => <file system path, FSFile, or TempFSFile>,
 539          *         'dst'                 => <storage path>,
 540          *         'headers'             => <HTTP header name/value map> # since 1.21
 541          *     ]
 542          * @endcode
 543          *
 544          * c) Copy a file within storage
 545          * @code
 546          *     [
 547          *         'op'                  => 'copy',
 548          *         'src'                 => <storage path>,
 549          *         'dst'                 => <storage path>,
 550          *         'ignoreMissingSource' => <boolean>, # since 1.21
 551          *         'headers'             => <HTTP header name/value map> # since 1.21
 552          *     ]
 553          * @endcode
 554          *
 555          * d) Move a file within storage
 556          * @code
 557          *     [
 558          *         'op'                  => 'move',
 559          *         'src'                 => <storage path>,
 560          *         'dst'                 => <storage path>,
 561          *         'ignoreMissingSource' => <boolean>, # since 1.21
 562          *         'headers'             => <HTTP header name/value map> # since 1.21
 563          *     ]
 564          * @endcode
 565          *
 566          * e) Delete a file within storage
 567          * @code
 568          *     [
 569          *         'op'                  => 'delete',
 570          *         'src'                 => <storage path>,
 571          *         'ignoreMissingSource' => <boolean>
 572          *     ]
 573          * @endcode
 574          *
 575          * f) Update metadata for a file within storage
 576          * @code
 577          *     [
 578          *         'op'                  => 'describe',
 579          *         'src'                 => <storage path>,
 580          *         'headers'             => <HTTP header name/value map>
 581          *     ]
 582          * @endcode
 583          *
 584          * g) Do nothing (no-op)
 585          * @code
 586          *     [
 587          *         'op'                  => 'null',
 588          *     ]
 589          * @endcode
 590          *
 591          * @par Boolean flags for operations (operation-specific):
 592          *   - ignoreMissingSource : The operation will simply succeed and do
 593          *                           nothing if the source file does not exist.
 594          *   - headers             : If supplied with a header name/value map, the backend will
 595          *                           reply with these headers when GETs/HEADs of the destination
 596          *                           file are made. Header values should be smaller than 256 bytes.
 597          *                           Content-Disposition headers can be longer, though the system
 598          *                           might ignore or truncate ones that are too long to store.
 599          *                           Existing headers will remain, but these will replace any
 600          *                           conflicting previous headers, and headers will be removed
 601          *                           if they are set to an empty string.
 602          *                           Backends that don't support metadata ignore this. (since 1.21)
 603          *
 604          * $opts is an associative of boolean flags, including:
 605          *   - bypassReadOnly      : Allow writes in read-only mode (since 1.20)
 606          *
 607          * @par Return value:
 608          * This returns a Status, which contains all warnings and fatals that occurred
 609          * during the operation. The 'failCount', 'successCount', and 'success' members
 610          * will reflect each operation attempted for the given files. The StatusValue will be
 611          * considered "OK" as long as no fatal errors occurred.
 612          *
 613          * @param array $ops Set of operations to execute
 614          * @param array $opts Batch operation options
 615          * @return StatusValue
 616          * @since 1.20
 617          */
 618         final public function doQuickOperations( array $ops, array $opts = [] ) {
 619                 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
 620                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 621                 }
 622                 if ( !count( $ops ) ) {
 623                         return $this->newStatus(); // nothing to do
 624                 }
 625
 626                 $ops = $this->resolveFSFileObjects( $ops );
 627                 foreach ( $ops as &$op ) {
 628                         $op['overwrite'] = true; // avoids RTTs in key/value stores
 629                 }
 630
 631                 /** @noinspection PhpUnusedLocalVariableInspection */
 632                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 633
 634                 return $this->doQuickOperationsInternal( $ops );
 635         }
 636
 637         /**
 638          * @see FileBackend::doQuickOperations()
 639          * @param array $ops
 640          * @since 1.20
 641          */
 642         abstract protected function doQuickOperationsInternal( array $ops );
 643
 644         /**
 645          * Same as doQuickOperations() except it takes a single operation.
 646          * If you are doing a batch of operations, then use that function instead.
 647          *
 648          * @see FileBackend::doQuickOperations()
 649          *
 650          * @param array $op Operation
 651          * @return StatusValue
 652          * @since 1.20
 653          */
 654         final public function doQuickOperation( array $op ) {
 655                 return $this->doQuickOperations( [ $op ] );
 656         }
 657
 658         /**
 659          * Performs a single quick create operation.
 660          * This sets $params['op'] to 'create' and passes it to doQuickOperation().
 661          *
 662          * @see FileBackend::doQuickOperation()
 663          *
 664          * @param array $params Operation parameters
 665          * @return StatusValue
 666          * @since 1.20
 667          */
 668         final public function quickCreate( array $params ) {
 669                 return $this->doQuickOperation( [ 'op' => 'create' ] + $params );
 670         }
 671
 672         /**
 673          * Performs a single quick store operation.
 674          * This sets $params['op'] to 'store' and passes it to doQuickOperation().
 675          *
 676          * @see FileBackend::doQuickOperation()
 677          *
 678          * @param array $params Operation parameters
 679          * @return StatusValue
 680          * @since 1.20
 681          */
 682         final public function quickStore( array $params ) {
 683                 return $this->doQuickOperation( [ 'op' => 'store' ] + $params );
 684         }
 685
 686         /**
 687          * Performs a single quick copy operation.
 688          * This sets $params['op'] to 'copy' and passes it to doQuickOperation().
 689          *
 690          * @see FileBackend::doQuickOperation()
 691          *
 692          * @param array $params Operation parameters
 693          * @return StatusValue
 694          * @since 1.20
 695          */
 696         final public function quickCopy( array $params ) {
 697                 return $this->doQuickOperation( [ 'op' => 'copy' ] + $params );
 698         }
 699
 700         /**
 701          * Performs a single quick move operation.
 702          * This sets $params['op'] to 'move' and passes it to doQuickOperation().
 703          *
 704          * @see FileBackend::doQuickOperation()
 705          *
 706          * @param array $params Operation parameters
 707          * @return StatusValue
 708          * @since 1.20
 709          */
 710         final public function quickMove( array $params ) {
 711                 return $this->doQuickOperation( [ 'op' => 'move' ] + $params );
 712         }
 713
 714         /**
 715          * Performs a single quick delete operation.
 716          * This sets $params['op'] to 'delete' and passes it to doQuickOperation().
 717          *
 718          * @see FileBackend::doQuickOperation()
 719          *
 720          * @param array $params Operation parameters
 721          * @return StatusValue
 722          * @since 1.20
 723          */
 724         final public function quickDelete( array $params ) {
 725                 return $this->doQuickOperation( [ 'op' => 'delete' ] + $params );
 726         }
 727
 728         /**
 729          * Performs a single quick describe operation.
 730          * This sets $params['op'] to 'describe' and passes it to doQuickOperation().
 731          *
 732          * @see FileBackend::doQuickOperation()
 733          *
 734          * @param array $params Operation parameters
 735          * @return StatusValue
 736          * @since 1.21
 737          */
 738         final public function quickDescribe( array $params ) {
 739                 return $this->doQuickOperation( [ 'op' => 'describe' ] + $params );
 740         }
 741
 742         /**
 743          * Concatenate a list of storage files into a single file system file.
 744          * The target path should refer to a file that is already locked or
 745          * otherwise safe from modification from other processes. Normally,
 746          * the file will be a new temp file, which should be adequate.
 747          *
 748          * @param array $params Operation parameters, include:
 749          *   - srcs        : ordered source storage paths (e.g. chunk1, chunk2, ...)
 750          *   - dst         : file system path to 0-byte temp file
 751          *   - parallelize : try to do operations in parallel when possible
 752          * @return StatusValue
 753          */
 754         abstract public function concatenate( array $params );
 755
 756         /**
 757          * Prepare a storage directory for usage.
 758          * This will create any required containers and parent directories.
 759          * Backends using key/value stores only need to create the container.
 760          *
 761          * The 'noAccess' and 'noListing' parameters works the same as in secure(),
 762          * except they are only applied *if* the directory/container had to be created.
 763          * These flags should always be set for directories that have private files.
 764          * However, setting them is not guaranteed to actually do anything.
 765          * Additional server configuration may be needed to achieve the desired effect.
 766          *
 767          * @param array $params Parameters include:
 768          *   - dir            : storage directory
 769          *   - noAccess       : try to deny file access (since 1.20)
 770          *   - noListing      : try to deny file listing (since 1.20)
 771          *   - bypassReadOnly : allow writes in read-only mode (since 1.20)
 772          * @return StatusValue
 773          */
 774         final public function prepare( array $params ) {
 775                 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
 776                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 777                 }
 778                 /** @noinspection PhpUnusedLocalVariableInspection */
 779                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 780                 return $this->doPrepare( $params );
 781         }
 782
 783         /**
 784          * @see FileBackend::prepare()
 785          * @param array $params
 786          */
 787         abstract protected function doPrepare( array $params );
 788
 789         /**
 790          * Take measures to block web access to a storage directory and
 791          * the container it belongs to. FS backends might add .htaccess
 792          * files whereas key/value store backends might revoke container
 793          * access to the storage user representing end-users in web requests.
 794          *
 795          * This is not guaranteed to actually make files or listings publically hidden.
 796          * Additional server configuration may be needed to achieve the desired effect.
 797          *
 798          * @param array $params Parameters include:
 799          *   - dir            : storage directory
 800          *   - noAccess       : try to deny file access
 801          *   - noListing      : try to deny file listing
 802          *   - bypassReadOnly : allow writes in read-only mode (since 1.20)
 803          * @return StatusValue
 804          */
 805         final public function secure( array $params ) {
 806                 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
 807                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 808                 }
 809                 /** @noinspection PhpUnusedLocalVariableInspection */
 810                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 811                 return $this->doSecure( $params );
 812         }
 813
 814         /**
 815          * @see FileBackend::secure()
 816          * @param array $params
 817          */
 818         abstract protected function doSecure( array $params );
 819
 820         /**
 821          * Remove measures to block web access to a storage directory and
 822          * the container it belongs to. FS backends might remove .htaccess
 823          * files whereas key/value store backends might grant container
 824          * access to the storage user representing end-users in web requests.
 825          * This essentially can undo the result of secure() calls.
 826          *
 827          * This is not guaranteed to actually make files or listings publically viewable.
 828          * Additional server configuration may be needed to achieve the desired effect.
 829          *
 830          * @param array $params Parameters include:
 831          *   - dir            : storage directory
 832          *   - access         : try to allow file access
 833          *   - listing        : try to allow file listing
 834          *   - bypassReadOnly : allow writes in read-only mode (since 1.20)
 835          * @return StatusValue
 836          * @since 1.20
 837          */
 838         final public function publish( array $params ) {
 839                 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
 840                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 841                 }
 842                 /** @noinspection PhpUnusedLocalVariableInspection */
 843                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 844                 return $this->doPublish( $params );
 845         }
 846
 847         /**
 848          * @see FileBackend::publish()
 849          * @param array $params
 850          */
 851         abstract protected function doPublish( array $params );
 852
 853         /**
 854          * Delete a storage directory if it is empty.
 855          * Backends using key/value stores may do nothing unless the directory
 856          * is that of an empty container, in which case it will be deleted.
 857          *
 858          * @param array $params Parameters include:
 859          *   - dir            : storage directory
 860          *   - recursive      : recursively delete empty subdirectories first (since 1.20)
 861          *   - bypassReadOnly : allow writes in read-only mode (since 1.20)
 862          * @return StatusValue
 863          */
 864         final public function clean( array $params ) {
 865                 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
 866                         return $this->newStatus( 'backend-fail-readonly', $this->name, $this->readOnly );
 867                 }
 868                 /** @noinspection PhpUnusedLocalVariableInspection */
 869                 $scope = $this->getScopedPHPBehaviorForOps(); // try to ignore client aborts
 870                 return $this->doClean( $params );
 871         }
 872
 873         /**
 874          * @see FileBackend::clean()
 875          * @param array $params
 876          */
 877         abstract protected function doClean( array $params );
 878
 879         /**
 880          * Enter file operation scope.
 881          * This just makes PHP ignore user aborts/disconnects until the return
 882          * value leaves scope. This returns null and does nothing in CLI mode.
 883          *
 884          * @return ScopedCallback|null
 885          */
 886         final protected function getScopedPHPBehaviorForOps() {
 887                 if ( PHP_SAPI != 'cli' ) { // http://bugs.php.net/bug.php?id=47540
 888                         $old = ignore_user_abort( true ); // avoid half-finished operations
 889                         return new ScopedCallback( function () use ( $old ) {
 890                                 ignore_user_abort( $old );
 891                         } );
 892                 }
 893
 894                 return null;
 895         }
 896
 897         /**
 898          * Check if a file exists at a storage path in the backend.
 899          * This returns false if only a directory exists at the path.
 900          *
 901          * @param array $params Parameters include:
 902          *   - src    : source storage path
 903          *   - latest : use the latest available data
 904          * @return bool|null Returns null on failure
 905          */
 906         abstract public function fileExists( array $params );
 907
 908         /**
 909          * Get the last-modified timestamp of the file at a storage path.
 910          *
 911          * @param array $params Parameters include:
 912          *   - src    : source storage path
 913          *   - latest : use the latest available data
 914          * @return string|bool TS_MW timestamp or false on failure
 915          */
 916         abstract public function getFileTimestamp( array $params );
 917
 918         /**
 919          * Get the contents of a file at a storage path in the backend.
 920          * This should be avoided for potentially large files.
 921          *
 922          * @param array $params Parameters include:
 923          *   - src    : source storage path
 924          *   - latest : use the latest available data
 925          * @return string|bool Returns false on failure
 926          */
 927         final public function getFileContents( array $params ) {
 928                 $contents = $this->getFileContentsMulti(
 929                         [ 'srcs' => [ $params['src'] ] ] + $params );
 930
 931                 return $contents[$params['src']];
 932         }
 933
 934         /**
 935          * Like getFileContents() except it takes an array of storage paths
 936          * and returns a map of storage paths to strings (or null on failure).
 937          * The map keys (paths) are in the same order as the provided list of paths.
 938          *
 939          * @see FileBackend::getFileContents()
 940          *
 941          * @param array $params Parameters include:
 942          *   - srcs        : list of source storage paths
 943          *   - latest      : use the latest available data
 944          *   - parallelize : try to do operations in parallel when possible
 945          * @return array Map of (path name => string or false on failure)
 946          * @since 1.20
 947          */
 948         abstract public function getFileContentsMulti( array $params );
 949
 950         /**
 951          * Get metadata about a file at a storage path in the backend.
 952          * If the file does not exist, then this returns false.
 953          * Otherwise, the result is an associative array that includes:
 954          *   - headers  : map of HTTP headers used for GET/HEAD requests (name => value)
 955          *   - metadata : map of file metadata (name => value)
 956          * Metadata keys and headers names will be returned in all lower-case.
 957          * Additional values may be included for internal use only.
 958          *
 959          * Use FileBackend::hasFeatures() to check how well this is supported.
 960          *
 961          * @param array $params
 962          * $params include:
 963          *   - src    : source storage path
 964          *   - latest : use the latest available data
 965          * @return array|bool Returns false on failure
 966          * @since 1.23
 967          */
 968         abstract public function getFileXAttributes( array $params );
 969
 970         /**
 971          * Get the size (bytes) of a file at a storage path in the backend.
 972          *
 973          * @param array $params Parameters include:
 974          *   - src    : source storage path
 975          *   - latest : use the latest available data
 976          * @return int|bool Returns false on failure
 977          */
 978         abstract public function getFileSize( array $params );
 979
 980         /**
 981          * Get quick information about a file at a storage path in the backend.
 982          * If the file does not exist, then this returns false.
 983          * Otherwise, the result is an associative array that includes:
 984          *   - mtime  : the last-modified timestamp (TS_MW)
 985          *   - size   : the file size (bytes)
 986          * Additional values may be included for internal use only.
 987          *
 988          * @param array $params Parameters include:
 989          *   - src    : source storage path
 990          *   - latest : use the latest available data
 991          * @return array|bool|null Returns null on failure
 992          */
 993         abstract public function getFileStat( array $params );
 994
 995         /**
 996          * Get a SHA-1 hash of the file at a storage path in the backend.
 997          *
 998          * @param array $params Parameters include:
 999          *   - src    : source storage path
1000          *   - latest : use the latest available data
1001          * @return string|bool Hash string or false on failure
1002          */
1003         abstract public function getFileSha1Base36( array $params );
1004
1005         /**
1006          * Get the properties of the file at a storage path in the backend.
1007          * This gives the result of FSFile::getProps() on a local copy of the file.
1008          *
1009          * @param array $params Parameters include:
1010          *   - src    : source storage path
1011          *   - latest : use the latest available data
1012          * @return array Returns FSFile::placeholderProps() on failure
1013          */
1014         abstract public function getFileProps( array $params );
1015
1016         /**
1017          * Stream the file at a storage path in the backend.
1018          *
1019          * If the file does not exists, an HTTP 404 error will be given.
1020          * Appropriate HTTP headers (Status, Content-Type, Content-Length)
1021          * will be sent if streaming began, while none will be sent otherwise.
1022          * Implementations should flush the output buffer before sending data.
1023          *
1024          * @param array $params Parameters include:
1025          *   - src      : source storage path
1026          *   - headers  : list of additional HTTP headers to send if the file exists
1027          *   - options  : HTTP request header map with lower case keys (since 1.28). Supports:
1028          *                range             : format is "bytes=(\d*-\d*)"
1029          *                if-modified-since : format is an HTTP date
1030          *   - headless : only include the body (and headers from "headers") (since 1.28)
1031          *   - latest   : use the latest available data
1032          *   - allowOB  : preserve any output buffers (since 1.28)
1033          * @return StatusValue
1034          */
1035         abstract public function streamFile( array $params );
1036
1037         /**
1038          * Returns a file system file, identical to the file at a storage path.
1039          * The file returned is either:
1040          *   - a) A local copy of the file at a storage path in the backend.
1041          *        The temporary copy will have the same extension as the source.
1042          *   - b) An original of the file at a storage path in the backend.
1043          * Temporary files may be purged when the file object falls out of scope.
1044          *
1045          * Write operations should *never* be done on this file as some backends
1046          * may do internal tracking or may be instances of FileBackendMultiWrite.
1047          * In that latter case, there are copies of the file that must stay in sync.
1048          * Additionally, further calls to this function may return the same file.
1049          *
1050          * @param array $params Parameters include:
1051          *   - src    : source storage path
1052          *   - latest : use the latest available data
1053          * @return FSFile|null Returns null on failure
1054          */
1055         final public function getLocalReference( array $params ) {
1056                 $fsFiles = $this->getLocalReferenceMulti(
1057                         [ 'srcs' => [ $params['src'] ] ] + $params );
1058
1059                 return $fsFiles[$params['src']];
1060         }
1061
1062         /**
1063          * Like getLocalReference() except it takes an array of storage paths
1064          * and returns a map of storage paths to FSFile objects (or null on failure).
1065          * The map keys (paths) are in the same order as the provided list of paths.
1066          *
1067          * @see FileBackend::getLocalReference()
1068          *
1069          * @param array $params Parameters include:
1070          *   - srcs        : list of source storage paths
1071          *   - latest      : use the latest available data
1072          *   - parallelize : try to do operations in parallel when possible
1073          * @return array Map of (path name => FSFile or null on failure)
1074          * @since 1.20
1075          */
1076         abstract public function getLocalReferenceMulti( array $params );
1077
1078         /**
1079          * Get a local copy on disk of the file at a storage path in the backend.
1080          * The temporary copy will have the same file extension as the source.
1081          * Temporary files may be purged when the file object falls out of scope.
1082          *
1083          * @param array $params Parameters include:
1084          *   - src    : source storage path
1085          *   - latest : use the latest available data
1086          * @return TempFSFile|null Returns null on failure
1087          */
1088         final public function getLocalCopy( array $params ) {
1089                 $tmpFiles = $this->getLocalCopyMulti(
1090                         [ 'srcs' => [ $params['src'] ] ] + $params );
1091
1092                 return $tmpFiles[$params['src']];
1093         }
1094
1095         /**
1096          * Like getLocalCopy() except it takes an array of storage paths and
1097          * returns a map of storage paths to TempFSFile objects (or null on failure).
1098          * The map keys (paths) are in the same order as the provided list of paths.
1099          *
1100          * @see FileBackend::getLocalCopy()
1101          *
1102          * @param array $params Parameters include:
1103          *   - srcs        : list of source storage paths
1104          *   - latest      : use the latest available data
1105          *   - parallelize : try to do operations in parallel when possible
1106          * @return array Map of (path name => TempFSFile or null on failure)
1107          * @since 1.20
1108          */
1109         abstract public function getLocalCopyMulti( array $params );
1110
1111         /**
1112          * Return an HTTP URL to a given file that requires no authentication to use.
1113          * The URL may be pre-authenticated (via some token in the URL) and temporary.
1114          * This will return null if the backend cannot make an HTTP URL for the file.
1115          *
1116          * This is useful for key/value stores when using scripts that seek around
1117          * large files and those scripts (and the backend) support HTTP Range headers.
1118          * Otherwise, one would need to use getLocalReference(), which involves loading
1119          * the entire file on to local disk.
1120          *
1121          * @param array $params Parameters include:
1122          *   - src : source storage path
1123          *   - ttl : lifetime (seconds) if pre-authenticated; default is 1 day
1124          * @return string|null
1125          * @since 1.21
1126          */
1127         abstract public function getFileHttpUrl( array $params );
1128
1129         /**
1130          * Check if a directory exists at a given storage path.
1131          * Backends using key/value stores will check if the path is a
1132          * virtual directory, meaning there are files under the given directory.
1133          *
1134          * Storage backends with eventual consistency might return stale data.
1135          *
1136          * @param array $params Parameters include:
1137          *   - dir : storage directory
1138          * @return bool|null Returns null on failure
1139          * @since 1.20
1140          */
1141         abstract public function directoryExists( array $params );
1142
1143         /**
1144          * Get an iterator to list *all* directories under a storage directory.
1145          * If the directory is of the form "mwstore://backend/container",
1146          * then all directories in the container will be listed.
1147          * If the directory is of form "mwstore://backend/container/dir",
1148          * then all directories directly under that directory will be listed.
1149          * Results will be storage directories relative to the given directory.
1150          *
1151          * Storage backends with eventual consistency might return stale data.
1152          *
1153          * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1154          *
1155          * @param array $params Parameters include:
1156          *   - dir     : storage directory
1157          *   - topOnly : only return direct child dirs of the directory
1158          * @return Traversable|array|null Returns null on failure
1159          * @since 1.20
1160          */
1161         abstract public function getDirectoryList( array $params );
1162
1163         /**
1164          * Same as FileBackend::getDirectoryList() except only lists
1165          * directories that are immediately under the given directory.
1166          *
1167          * Storage backends with eventual consistency might return stale data.
1168          *
1169          * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1170          *
1171          * @param array $params Parameters include:
1172          *   - dir : storage directory
1173          * @return Traversable|array|null Returns null on failure
1174          * @since 1.20
1175          */
1176         final public function getTopDirectoryList( array $params ) {
1177                 return $this->getDirectoryList( [ 'topOnly' => true ] + $params );
1178         }
1179
1180         /**
1181          * Get an iterator to list *all* stored files under a storage directory.
1182          * If the directory is of the form "mwstore://backend/container",
1183          * then all files in the container will be listed.
1184          * If the directory is of form "mwstore://backend/container/dir",
1185          * then all files under that directory will be listed.
1186          * Results will be storage paths relative to the given directory.
1187          *
1188          * Storage backends with eventual consistency might return stale data.
1189          *
1190          * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1191          *
1192          * @param array $params Parameters include:
1193          *   - dir        : storage directory
1194          *   - topOnly    : only return direct child files of the directory (since 1.20)
1195          *   - adviseStat : set to true if stat requests will be made on the files (since 1.22)
1196          * @return Traversable|array|null Returns null on failure
1197          */
1198         abstract public function getFileList( array $params );
1199
1200         /**
1201          * Same as FileBackend::getFileList() except only lists
1202          * files that are immediately under the given directory.
1203          *
1204          * Storage backends with eventual consistency might return stale data.
1205          *
1206          * Failures during iteration can result in FileBackendError exceptions (since 1.22).
1207          *
1208          * @param array $params Parameters include:
1209          *   - dir        : storage directory
1210          *   - adviseStat : set to true if stat requests will be made on the files (since 1.22)
1211          * @return Traversable|array|null Returns null on failure
1212          * @since 1.20
1213          */
1214         final public function getTopFileList( array $params ) {
1215                 return $this->getFileList( [ 'topOnly' => true ] + $params );
1216         }
1217
1218         /**
1219          * Preload persistent file stat cache and property cache into in-process cache.
1220          * This should be used when stat calls will be made on a known list of a many files.
1221          *
1222          * @see FileBackend::getFileStat()
1223          *
1224          * @param array $paths Storage paths
1225          */
1226         abstract public function preloadCache( array $paths );
1227
1228         /**
1229          * Invalidate any in-process file stat and property cache.
1230          * If $paths is given, then only the cache for those files will be cleared.
1231          *
1232          * @see FileBackend::getFileStat()
1233          *
1234          * @param array $paths Storage paths (optional)
1235          */
1236         abstract public function clearCache( array $paths = null );
1237
1238         /**
1239          * Preload file stat information (concurrently if possible) into in-process cache.
1240          *
1241          * This should be used when stat calls will be made on a known list of a many files.
1242          * This does not make use of the persistent file stat cache.
1243          *
1244          * @see FileBackend::getFileStat()
1245          *
1246          * @param array $params Parameters include:
1247          *   - srcs        : list of source storage paths
1248          *   - latest      : use the latest available data
1249          * @return bool All requests proceeded without I/O errors (since 1.24)
1250          * @since 1.23
1251          */
1252         abstract public function preloadFileStat( array $params );
1253
1254         /**
1255          * Lock the files at the given storage paths in the backend.
1256          * This will either lock all the files or none (on failure).
1257          *
1258          * Callers should consider using getScopedFileLocks() instead.
1259          *
1260          * @param array $paths Storage paths
1261          * @param int $type LockManager::LOCK_* constant
1262          * @param int $timeout Timeout in seconds (0 means non-blocking) (since 1.24)
1263          * @return StatusValue
1264          */
1265         final public function lockFiles( array $paths, $type, $timeout = 0 ) {
1266                 $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1267
1268                 return $this->wrapStatus( $this->lockManager->lock( $paths, $type, $timeout ) );
1269         }
1270
1271         /**
1272          * Unlock the files at the given storage paths in the backend.
1273          *
1274          * @param array $paths Storage paths
1275          * @param int $type LockManager::LOCK_* constant
1276          * @return StatusValue
1277          */
1278         final public function unlockFiles( array $paths, $type ) {
1279                 $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1280
1281                 return $this->wrapStatus( $this->lockManager->unlock( $paths, $type ) );
1282         }
1283
1284         /**
1285          * Lock the files at the given storage paths in the backend.
1286          * This will either lock all the files or none (on failure).
1287          * On failure, the StatusValue object will be updated with errors.
1288          *
1289          * Once the return value goes out scope, the locks will be released and
1290          * the StatusValue updated. Unlock fatals will not change the StatusValue "OK" value.
1291          *
1292          * @see ScopedLock::factory()
1293          *
1294          * @param array $paths List of storage paths or map of lock types to path lists
1295          * @param int|string $type LockManager::LOCK_* constant or "mixed"
1296          * @param StatusValue $status StatusValue to update on lock/unlock
1297          * @param int $timeout Timeout in seconds (0 means non-blocking) (since 1.24)
1298          * @return ScopedLock|null Returns null on failure
1299          */
1300         final public function getScopedFileLocks(
1301                 array $paths, $type, StatusValue $status, $timeout = 0
1302         ) {
1303                 if ( $type === 'mixed' ) {
1304                         foreach ( $paths as &$typePaths ) {
1305                                 $typePaths = array_map( 'FileBackend::normalizeStoragePath', $typePaths );
1306                         }
1307                 } else {
1308                         $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1309                 }
1310
1311                 return ScopedLock::factory( $this->lockManager, $paths, $type, $status, $timeout );
1312         }
1313
1314         /**
1315          * Get an array of scoped locks needed for a batch of file operations.
1316          *
1317          * Normally, FileBackend::doOperations() handles locking, unless
1318          * the 'nonLocking' param is passed in. This function is useful if you
1319          * want the files to be locked for a broader scope than just when the
1320          * files are changing. For example, if you need to update DB metadata,
1321          * you may want to keep the files locked until finished.
1322          *
1323          * @see FileBackend::doOperations()
1324          *
1325          * @param array $ops List of file operations to FileBackend::doOperations()
1326          * @param StatusValue $status StatusValue to update on lock/unlock
1327          * @return ScopedLock|null
1328          * @since 1.20
1329          */
1330         abstract public function getScopedLocksForOps( array $ops, StatusValue $status );
1331
1332         /**
1333          * Get the root storage path of this backend.
1334          * All container paths are "subdirectories" of this path.
1335          *
1336          * @return string Storage path
1337          * @since 1.20
1338          */
1339         final public function getRootStoragePath() {
1340                 return "mwstore://{$this->name}";
1341         }
1342
1343         /**
1344          * Get the storage path for the given container for this backend
1345          *
1346          * @param string $container Container name
1347          * @return string Storage path
1348          * @since 1.21
1349          */
1350         final public function getContainerStoragePath( $container ) {
1351                 return $this->getRootStoragePath() . "/{$container}";
1352         }
1353
1354         /**
1355          * Get the file journal object for this backend
1356          *
1357          * @return FileJournal
1358          */
1359         final public function getJournal() {
1360                 return $this->fileJournal;
1361         }
1362
1363         /**
1364          * Convert FSFile 'src' paths to string paths (with an 'srcRef' field set to the FSFile)
1365          *
1366          * The 'srcRef' field keeps any TempFSFile objects in scope for the backend to have it
1367          * around as long it needs (which may vary greatly depending on configuration)
1368          *
1369          * @param array $ops File operation batch for FileBaclend::doOperations()
1370          * @return array File operation batch
1371          */
1372         protected function resolveFSFileObjects( array $ops ) {
1373                 foreach ( $ops as &$op ) {
1374                         $src = isset( $op['src'] ) ? $op['src'] : null;
1375                         if ( $src instanceof FSFile ) {
1376                                 $op['srcRef'] = $src;
1377                                 $op['src'] = $src->getPath();
1378                         }
1379                 }
1380                 unset( $op );
1381
1382                 return $ops;
1383         }
1384
1385         /**
1386          * Check if a given path is a "mwstore://" path.
1387          * This does not do any further validation or any existence checks.
1388          *
1389          * @param string $path
1390          * @return bool
1391          */
1392         final public static function isStoragePath( $path ) {
1393                 return ( strpos( $path, 'mwstore://' ) === 0 );
1394         }
1395
1396         /**
1397          * Split a storage path into a backend name, a container name,
1398          * and a relative file path. The relative path may be the empty string.
1399          * This does not do any path normalization or traversal checks.
1400          *
1401          * @param string $storagePath
1402          * @return array (backend, container, rel object) or (null, null, null)
1403          */
1404         final public static function splitStoragePath( $storagePath ) {
1405                 if ( self::isStoragePath( $storagePath ) ) {
1406                         // Remove the "mwstore://" prefix and split the path
1407                         $parts = explode( '/', substr( $storagePath, 10 ), 3 );
1408                         if ( count( $parts ) >= 2 && $parts[0] != '' && $parts[1] != '' ) {
1409                                 if ( count( $parts ) == 3 ) {
1410                                         return $parts; // e.g. "backend/container/path"
1411                                 } else {
1412                                         return [ $parts[0], $parts[1], '' ]; // e.g. "backend/container"
1413                                 }
1414                         }
1415                 }
1416
1417                 return [ null, null, null ];
1418         }
1419
1420         /**
1421          * Normalize a storage path by cleaning up directory separators.
1422          * Returns null if the path is not of the format of a valid storage path.
1423          *
1424          * @param string $storagePath
1425          * @return string|null
1426          */
1427         final public static function normalizeStoragePath( $storagePath ) {
1428                 list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
1429                 if ( $relPath !== null ) { // must be for this backend
1430                         $relPath = self::normalizeContainerPath( $relPath );
1431                         if ( $relPath !== null ) {
1432                                 return ( $relPath != '' )
1433                                         ? "mwstore://{$backend}/{$container}/{$relPath}"
1434                                         : "mwstore://{$backend}/{$container}";
1435                         }
1436                 }
1437
1438                 return null;
1439         }
1440
1441         /**
1442          * Get the parent storage directory of a storage path.
1443          * This returns a path like "mwstore://backend/container",
1444          * "mwstore://backend/container/...", or null if there is no parent.
1445          *
1446          * @param string $storagePath
1447          * @return string|null
1448          */
1449         final public static function parentStoragePath( $storagePath ) {
1450                 $storagePath = dirname( $storagePath );
1451                 list( , , $rel ) = self::splitStoragePath( $storagePath );
1452
1453                 return ( $rel === null ) ? null : $storagePath;
1454         }
1455
1456         /**
1457          * Get the final extension from a storage or FS path
1458          *
1459          * @param string $path
1460          * @param string $case One of (rawcase, uppercase, lowercase) (since 1.24)
1461          * @return string
1462          */
1463         final public static function extensionFromPath( $path, $case = 'lowercase' ) {
1464                 $i = strrpos( $path, '.' );
1465                 $ext = $i ? substr( $path, $i + 1 ) : '';
1466
1467                 if ( $case === 'lowercase' ) {
1468                         $ext = strtolower( $ext );
1469                 } elseif ( $case === 'uppercase' ) {
1470                         $ext = strtoupper( $ext );
1471                 }
1472
1473                 return $ext;
1474         }
1475
1476         /**
1477          * Check if a relative path has no directory traversals
1478          *
1479          * @param string $path
1480          * @return bool
1481          * @since 1.20
1482          */
1483         final public static function isPathTraversalFree( $path ) {
1484                 return ( self::normalizeContainerPath( $path ) !== null );
1485         }
1486
1487         /**
1488          * Build a Content-Disposition header value per RFC 6266.
1489          *
1490          * @param string $type One of (attachment, inline)
1491          * @param string $filename Suggested file name (should not contain slashes)
1492          * @throws FileBackendError
1493          * @return string
1494          * @since 1.20
1495          */
1496         final public static function makeContentDisposition( $type, $filename = '' ) {
1497                 $parts = [];
1498
1499                 $type = strtolower( $type );
1500                 if ( !in_array( $type, [ 'inline', 'attachment' ] ) ) {
1501                         throw new InvalidArgumentException( "Invalid Content-Disposition type '$type'." );
1502                 }
1503                 $parts[] = $type;
1504
1505                 if ( strlen( $filename ) ) {
1506                         $parts[] = "filename*=UTF-8''" . rawurlencode( basename( $filename ) );
1507                 }
1508
1509                 return implode( ';', $parts );
1510         }
1511
1512         /**
1513          * Validate and normalize a relative storage path.
1514          * Null is returned if the path involves directory traversal.
1515          * Traversal is insecure for FS backends and broken for others.
1516          *
1517          * This uses the same traversal protection as Title::secureAndSplit().
1518          *
1519          * @param string $path Storage path relative to a container
1520          * @return string|null
1521          */
1522         final protected static function normalizeContainerPath( $path ) {
1523                 // Normalize directory separators
1524                 $path = strtr( $path, '\\', '/' );
1525                 // Collapse any consecutive directory separators
1526                 $path = preg_replace( '![/]{2,}!', '/', $path );
1527                 // Remove any leading directory separator
1528                 $path = ltrim( $path, '/' );
1529                 // Use the same traversal protection as Title::secureAndSplit()
1530                 if ( strpos( $path, '.' ) !== false ) {
1531                         if (
1532                                 $path === '.' ||
1533                                 $path === '..' ||
1534                                 strpos( $path, './' ) === 0 ||
1535                                 strpos( $path, '../' ) === 0 ||
1536                                 strpos( $path, '/./' ) !== false ||
1537                                 strpos( $path, '/../' ) !== false
1538                         ) {
1539                                 return null;
1540                         }
1541                 }
1542
1543                 return $path;
1544         }
1545
1546         /**
1547          * Yields the result of the status wrapper callback on either:
1548          *   - StatusValue::newGood() if this method is called without parameters
1549          *   - StatusValue::newFatal() with all parameters to this method if passed in
1550          *
1551          * @param ... string
1552          * @return StatusValue
1553          */
1554         final protected function newStatus() {
1555                 $args = func_get_args();
1556                 if ( count( $args ) ) {
1557                         $sv = call_user_func_array( [ 'StatusValue', 'newFatal' ], $args );
1558                 } else {
1559                         $sv = StatusValue::newGood();
1560                 }
1561
1562                 return $this->wrapStatus( $sv );
1563         }
1564
1565         /**
1566          * @param StatusValue $sv
1567          * @return StatusValue Modified status or StatusValue subclass
1568          */
1569         final protected function wrapStatus( StatusValue $sv ) {
1570                 return $this->statusWrapper ? call_user_func( $this->statusWrapper, $sv ) : $sv;
1571         }
1572 }