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