includes/filebackend/FileBackendMultiWrite.php

   1 <?php
   2 /**
   3  * Proxy backend that mirrors writes to several internal backends.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  * @author Aaron Schulz
  23  */
  24
  25 /**
  26  * @brief Proxy backend that mirrors writes to several internal backends.
  27  *
  28  * This class defines a multi-write backend. Multiple backends can be
  29  * registered to this proxy backend and it will act as a single backend.
  30  * Use this when all access to those backends is through this proxy backend.
  31  * At least one of the backends must be declared the "master" backend.
  32  *
  33  * Only use this class when transitioning from one storage system to another.
  34  *
  35  * Read operations are only done on the 'master' backend for consistency.
  36  * Write operations are performed on all backends, in the order defined.
  37  * If an operation fails on one backend it will be rolled back from the others.
  38  *
  39  * @ingroup FileBackend
  40  * @since 1.19
  41  */
  42 class FileBackendMultiWrite extends FileBackend {
  43         /** @var Array Prioritized list of FileBackendStore objects */
  44         protected $backends = array(); // array of (backend index => backends)
  45         protected $masterIndex = -1; // integer; index of master backend
  46         protected $syncChecks = 0; // integer; bitfield
  47         protected $autoResync = false; // boolean
  48
  49         /** @var Array */
  50         protected $noPushDirConts = array();
  51         protected $noPushQuickOps = false; // boolean
  52
  53         /* Possible internal backend consistency checks */
  54         const CHECK_SIZE = 1;
  55         const CHECK_TIME = 2;
  56         const CHECK_SHA1 = 4;
  57
  58         /**
  59          * Construct a proxy backend that consists of several internal backends.
  60          * Locking, journaling, and read-only checks are handled by the proxy backend.
  61          *
  62          * Additional $config params include:
  63          *   - backends       : Array of backend config and multi-backend settings.
  64          *                      Each value is the config used in the constructor of a
  65          *                      FileBackendStore class, but with these additional settings:
  66          *                        - class         : The name of the backend class
  67          *                        - isMultiMaster : This must be set for one backend.
  68          *                        - template:     : If given a backend name, this will use
  69          *                                          the config of that backend as a template.
  70          *                                          Values specified here take precedence.
  71          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  72          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  73          *                      There are constants for SIZE, TIME, and SHA1.
  74          *                      The checks are done before allowing any file operations.
  75          *   - autoResync     : Automatically resync the clone backends to the master backend
  76          *                      when pre-operation sync checks fail. This should only be used
  77          *                      if the master backend is stable and not missing any files.
  78          *                      Use "conservative" to limit resyncing to copying newer master
  79          *                      backend files over older (or non-existing) clone backend files.
  80          *                      Cases that cannot be handled will result in operation abortion.
  81          *   - noPushQuickOps : (hack) Only apply doQuickOperations() to the master backend.
  82          *   - noPushDirConts : (hack) Only apply directory functions to the master backend.
  83          *
  84          * @param Array $config
  85          * @throws MWException
  86          */
  87         public function __construct( array $config ) {
  88                 parent::__construct( $config );
  89                 $this->syncChecks = isset( $config['syncChecks'] )
  90                         ? $config['syncChecks']
  91                         : self::CHECK_SIZE;
  92                 $this->autoResync = isset( $config['autoResync'] )
  93                         ? $config['autoResync']
  94                         : false;
  95                 $this->noPushQuickOps = isset( $config['noPushQuickOps'] )
  96                         ? $config['noPushQuickOps']
  97                         : false;
  98                 $this->noPushDirConts = isset( $config['noPushDirConts'] )
  99                         ? $config['noPushDirConts']
 100                         : array();
 101                 // Construct backends here rather than via registration
 102                 // to keep these backends hidden from outside the proxy.
 103                 $namesUsed = array();
 104                 foreach ( $config['backends'] as $index => $config ) {
 105                         if ( isset( $config['template'] ) ) {
 106                                 // Config is just a modified version of a registered backend's.
 107                                 // This should only be used when that config is used only by this backend.
 108                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
 109                         }
 110                         $name = $config['name'];
 111                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 112                                 throw new MWException( "Two or more backends defined with the name $name." );
 113                         }
 114                         $namesUsed[$name] = 1;
 115                         // Alter certain sub-backend settings for sanity
 116                         unset( $config['readOnly'] ); // use proxy backend setting
 117                         unset( $config['fileJournal'] ); // use proxy backend journal
 118                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
 119                         $config['lockManager'] = 'nullLockManager'; // lock under proxy backend
 120                         if ( !empty( $config['isMultiMaster'] ) ) {
 121                                 if ( $this->masterIndex >= 0 ) {
 122                                         throw new MWException( 'More than one master backend defined.' );
 123                                 }
 124                                 $this->masterIndex = $index; // this is the "master"
 125                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 126                         }
 127                         // Create sub-backend object
 128                         if ( !isset( $config['class'] ) ) {
 129                                 throw new MWException( 'No class given for a backend config.' );
 130                         }
 131                         $class = $config['class'];
 132                         $this->backends[$index] = new $class( $config );
 133                 }
 134                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 135                         throw new MWException( 'No master backend defined.' );
 136                 }
 137         }
 138
 139         final protected function doOperationsInternal( array $ops, array $opts ) {
 140                 $status = Status::newGood();
 141
 142                 $mbe = $this->backends[$this->masterIndex]; // convenience
 143
 144                 // Try to lock those files for the scope of this function...
 145                 if ( empty( $opts['nonLocking'] ) ) {
 146                         // Try to lock those files for the scope of this function...
 147                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 148                         if ( !$status->isOK() ) {
 149                                 return $status; // abort
 150                         }
 151                 }
 152                 // Clear any cache entries (after locks acquired)
 153                 $this->clearCache();
 154                 $opts['preserveCache'] = true; // only locked files are cached
 155                 // Get the list of paths to read/write...
 156                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 157                 // Check if the paths are valid and accessible on all backends...
 158                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 159                 if ( !$status->isOK() ) {
 160                         return $status; // abort
 161                 }
 162                 // Do a consistency check to see if the backends are consistent...
 163                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 164                 if ( !$syncStatus->isOK() ) {
 165                         wfDebugLog( 'FileOperation', get_class( $this ) .
 166                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 167                         // Try to resync the clone backends to the master on the spot...
 168                         if ( !$this->autoResync || !$this->resyncFiles( $relevantPaths )->isOK() ) {
 169                                 $status->merge( $syncStatus );
 170                                 return $status; // abort
 171                         }
 172                 }
 173                 // Actually attempt the operation batch on the master backend...
 174                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 175                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 176                 $status->merge( $masterStatus );
 177                 // Propagate the operations to the clone backends if there were no unexpected errors
 178                 // and if there were either no expected errors or if the 'force' option was used.
 179                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 180                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 181                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 182                         foreach ( $this->backends as $index => $backend ) {
 183                                 if ( $index !== $this->masterIndex ) { // not done already
 184                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 185                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 186                                 }
 187                         }
 188                 }
 189                 // Make 'success', 'successCount', and 'failCount' fields reflect
 190                 // the overall operation, rather than all the batches for each backend.
 191                 // Do this by only using success values from the master backend's batch.
 192                 $status->success = $masterStatus->success;
 193                 $status->successCount = $masterStatus->successCount;
 194                 $status->failCount = $masterStatus->failCount;
 195
 196                 return $status;
 197         }
 198
 199         /**
 200          * Check that a set of files are consistent across all internal backends
 201          *
 202          * @param array $paths List of storage paths
 203          * @return Status
 204          */
 205         public function consistencyCheck( array $paths ) {
 206                 $status = Status::newGood();
 207                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 208                         return $status; // skip checks
 209                 }
 210
 211                 $mBackend = $this->backends[$this->masterIndex];
 212                 foreach ( $paths as $path ) {
 213                         $params = array( 'src' => $path, 'latest' => true );
 214                         $mParams = $this->substOpPaths( $params, $mBackend );
 215                         // Stat the file on the 'master' backend
 216                         $mStat = $mBackend->getFileStat( $mParams );
 217                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 218                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 219                         } else {
 220                                 $mSha1 = false;
 221                         }
 222                         // Check if all clone backends agree with the master...
 223                         foreach ( $this->backends as $index => $cBackend ) {
 224                                 if ( $index === $this->masterIndex ) {
 225                                         continue; // master
 226                                 }
 227                                 $cParams = $this->substOpPaths( $params, $cBackend );
 228                                 $cStat = $cBackend->getFileStat( $cParams );
 229                                 if ( $mStat ) { // file is in master
 230                                         if ( !$cStat ) { // file should exist
 231                                                 $status->fatal( 'backend-fail-synced', $path );
 232                                                 continue;
 233                                         }
 234                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 235                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 236                                                         $status->fatal( 'backend-fail-synced', $path );
 237                                                         continue;
 238                                                 }
 239                                         }
 240                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 241                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 242                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 243                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 244                                                         $status->fatal( 'backend-fail-synced', $path );
 245                                                         continue;
 246                                                 }
 247                                         }
 248                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 249                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 250                                                         $status->fatal( 'backend-fail-synced', $path );
 251                                                         continue;
 252                                                 }
 253                                         }
 254                                 } else { // file is not in master
 255                                         if ( $cStat ) { // file should not exist
 256                                                 $status->fatal( 'backend-fail-synced', $path );
 257                                         }
 258                                 }
 259                         }
 260                 }
 261
 262                 return $status;
 263         }
 264
 265         /**
 266          * Check that a set of file paths are usable across all internal backends
 267          *
 268          * @param array $paths List of storage paths
 269          * @return Status
 270          */
 271         public function accessibilityCheck( array $paths ) {
 272                 $status = Status::newGood();
 273                 if ( count( $this->backends ) <= 1 ) {
 274                         return $status; // skip checks
 275                 }
 276
 277                 foreach ( $paths as $path ) {
 278                         foreach ( $this->backends as $backend ) {
 279                                 $realPath = $this->substPaths( $path, $backend );
 280                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 281                                         $status->fatal( 'backend-fail-usable', $path );
 282                                 }
 283                         }
 284                 }
 285
 286                 return $status;
 287         }
 288
 289         /**
 290          * Check that a set of files are consistent across all internal backends
 291          * and re-synchronize those files againt the "multi master" if needed.
 292          *
 293          * @param array $paths List of storage paths
 294          * @return Status
 295          */
 296         public function resyncFiles( array $paths ) {
 297                 $status = Status::newGood();
 298
 299                 $mBackend = $this->backends[$this->masterIndex];
 300                 foreach ( $paths as $path ) {
 301                         $mPath = $this->substPaths( $path, $mBackend );
 302                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 303                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 304                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 305                                 $status->fatal( 'backend-fail-internal', $this->name );
 306                                 continue; // file is not available on the master backend...
 307                         }
 308                         // Check of all clone backends agree with the master...
 309                         foreach ( $this->backends as $index => $cBackend ) {
 310                                 if ( $index === $this->masterIndex ) {
 311                                         continue; // master
 312                                 }
 313                                 $cPath = $this->substPaths( $path, $cBackend );
 314                                 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath, 'latest' => true ) );
 315                                 $cStat = $cBackend->getFileStat( array( 'src' => $cPath, 'latest' => true ) );
 316                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 317                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 318                                         continue; // file is not available on the clone backend...
 319                                 }
 320                                 if ( $mSha1 === $cSha1 ) {
 321                                         // already synced; nothing to do
 322                                 } elseif ( $mSha1 !== false ) { // file is in master
 323                                         if ( $this->autoResync === 'conservative'
 324                                                 && $cStat && $cStat['mtime'] > $mStat['mtime'] )
 325                                         {
 326                                                 $status->fatal( 'backend-fail-synced', $path );
 327                                                 continue; // don't rollback data
 328                                         }
 329                                         $fsFile = $mBackend->getLocalReference(
 330                                                 array( 'src' => $mPath, 'latest' => true ) );
 331                                         $status->merge( $cBackend->quickStore(
 332                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 333                                         ) );
 334                                 } elseif ( $mStat === false ) { // file is not in master
 335                                         if ( $this->autoResync === 'conservative' ) {
 336                                                 $status->fatal( 'backend-fail-synced', $path );
 337                                                 continue; // don't delete data
 338                                         }
 339                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 340                                 }
 341                         }
 342                 }
 343
 344                 return $status;
 345         }
 346
 347         /**
 348          * Get a list of file storage paths to read or write for a list of operations
 349          *
 350          * @param array $ops Same format as doOperations()
 351          * @return Array List of storage paths to files (does not include directories)
 352          */
 353         protected function fileStoragePathsForOps( array $ops ) {
 354                 $paths = array();
 355                 foreach ( $ops as $op ) {
 356                         if ( isset( $op['src'] ) ) {
 357                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 358                                 // is no source file, nothing should happen and there should be no errors.
 359                                 if ( empty( $op['ignoreMissingSource'] )
 360                                         || $this->fileExists( array( 'src' => $op['src'] ) ) )
 361                                 {
 362                                         $paths[] = $op['src'];
 363                                 }
 364                         }
 365                         if ( isset( $op['srcs'] ) ) {
 366                                 $paths = array_merge( $paths, $op['srcs'] );
 367                         }
 368                         if ( isset( $op['dst'] ) ) {
 369                                 $paths[] = $op['dst'];
 370                         }
 371                 }
 372                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 373         }
 374
 375         /**
 376          * Substitute the backend name in storage path parameters
 377          * for a set of operations with that of a given internal backend.
 378          *
 379          * @param array $ops List of file operation arrays
 380          * @param FileBackendStore $backend
 381          * @return Array
 382          */
 383         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 384                 $newOps = array(); // operations
 385                 foreach ( $ops as $op ) {
 386                         $newOp = $op; // operation
 387                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 388                                 if ( isset( $newOp[$par] ) ) { // string or array
 389                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 390                                 }
 391                         }
 392                         $newOps[] = $newOp;
 393                 }
 394                 return $newOps;
 395         }
 396
 397         /**
 398          * Same as substOpBatchPaths() but for a single operation
 399          *
 400          * @param array $ops File operation array
 401          * @param FileBackendStore $backend
 402          * @return Array
 403          */
 404         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 405                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 406                 return $newOps[0];
 407         }
 408
 409         /**
 410          * Substitute the backend of storage paths with an internal backend's name
 411          *
 412          * @param array|string $paths List of paths or single string path
 413          * @param FileBackendStore $backend
 414          * @return Array|string
 415          */
 416         protected function substPaths( $paths, FileBackendStore $backend ) {
 417                 return preg_replace(
 418                         '!^mwstore://' . preg_quote( $this->name ) . '/!',
 419                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 420                         $paths // string or array
 421                 );
 422         }
 423
 424         /**
 425          * Substitute the backend of internal storage paths with the proxy backend's name
 426          *
 427          * @param array|string $paths List of paths or single string path
 428          * @return Array|string
 429          */
 430         protected function unsubstPaths( $paths ) {
 431                 return preg_replace(
 432                         '!^mwstore://([^/]+)!',
 433                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 434                         $paths // string or array
 435                 );
 436         }
 437
 438         protected function doQuickOperationsInternal( array $ops ) {
 439                 $status = Status::newGood();
 440                 // Do the operations on the master backend; setting Status fields...
 441                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 442                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 443                 $status->merge( $masterStatus );
 444                 // Propagate the operations to the clone backends...
 445                 if ( !$this->noPushQuickOps ) {
 446                         foreach ( $this->backends as $index => $backend ) {
 447                                 if ( $index !== $this->masterIndex ) { // not done already
 448                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 449                                         $status->merge( $backend->doQuickOperations( $realOps ) );
 450                                 }
 451                         }
 452                 }
 453                 // Make 'success', 'successCount', and 'failCount' fields reflect
 454                 // the overall operation, rather than all the batches for each backend.
 455                 // Do this by only using success values from the master backend's batch.
 456                 $status->success = $masterStatus->success;
 457                 $status->successCount = $masterStatus->successCount;
 458                 $status->failCount = $masterStatus->failCount;
 459                 return $status;
 460         }
 461
 462         /**
 463          * @param string $path Storage path
 464          * @return bool Path container should have dir changes pushed to all backends
 465          */
 466         protected function replicateContainerDirChanges( $path ) {
 467                 list( , $shortCont, ) = self::splitStoragePath( $path );
 468                 return !in_array( $shortCont, $this->noPushDirConts );
 469         }
 470
 471         protected function doPrepare( array $params ) {
 472                 $status = Status::newGood();
 473                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 474                 foreach ( $this->backends as $index => $backend ) {
 475                         if ( $replicate || $index == $this->masterIndex ) {
 476                                 $realParams = $this->substOpPaths( $params, $backend );
 477                                 $status->merge( $backend->doPrepare( $realParams ) );
 478                         }
 479                 }
 480                 return $status;
 481         }
 482
 483         protected function doSecure( array $params ) {
 484                 $status = Status::newGood();
 485                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 486                 foreach ( $this->backends as $index => $backend ) {
 487                         if ( $replicate || $index == $this->masterIndex ) {
 488                                 $realParams = $this->substOpPaths( $params, $backend );
 489                                 $status->merge( $backend->doSecure( $realParams ) );
 490                         }
 491                 }
 492                 return $status;
 493         }
 494
 495         protected function doPublish( array $params ) {
 496                 $status = Status::newGood();
 497                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 498                 foreach ( $this->backends as $index => $backend ) {
 499                         if ( $replicate || $index == $this->masterIndex ) {
 500                                 $realParams = $this->substOpPaths( $params, $backend );
 501                                 $status->merge( $backend->doPublish( $realParams ) );
 502                         }
 503                 }
 504                 return $status;
 505         }
 506
 507         protected function doClean( array $params ) {
 508                 $status = Status::newGood();
 509                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 510                 foreach ( $this->backends as $index => $backend ) {
 511                         if ( $replicate || $index == $this->masterIndex ) {
 512                                 $realParams = $this->substOpPaths( $params, $backend );
 513                                 $status->merge( $backend->doClean( $realParams ) );
 514                         }
 515                 }
 516                 return $status;
 517         }
 518
 519         public function concatenate( array $params ) {
 520                 // We are writing to an FS file, so we don't need to do this per-backend
 521                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 522                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 523         }
 524
 525         public function fileExists( array $params ) {
 526                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 527                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 528         }
 529
 530         public function getFileTimestamp( array $params ) {
 531                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 532                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 533         }
 534
 535         public function getFileSize( array $params ) {
 536                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 537                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 538         }
 539
 540         public function getFileStat( array $params ) {
 541                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 542                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 543         }
 544
 545         public function getFileContentsMulti( array $params ) {
 546                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 547                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 548
 549                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 550                 foreach ( $contentsM as $path => $data ) {
 551                         $contents[$this->unsubstPaths( $path )] = $data;
 552                 }
 553                 return $contents;
 554         }
 555
 556         public function getFileSha1Base36( array $params ) {
 557                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 558                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 559         }
 560
 561         public function getFileProps( array $params ) {
 562                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 563                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 564         }
 565
 566         public function streamFile( array $params ) {
 567                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 568                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 569         }
 570
 571         public function getLocalReferenceMulti( array $params ) {
 572                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 573                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 574
 575                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 576                 foreach ( $fsFilesM as $path => $fsFile ) {
 577                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 578                 }
 579                 return $fsFiles;
 580         }
 581
 582         public function getLocalCopyMulti( array $params ) {
 583                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 584                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 585
 586                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 587                 foreach ( $tempFilesM as $path => $tempFile ) {
 588                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 589                 }
 590                 return $tempFiles;
 591         }
 592
 593         public function getFileHttpUrl( array $params ) {
 594                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 595                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 596         }
 597
 598         public function directoryExists( array $params ) {
 599                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 600                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 601         }
 602
 603         public function getDirectoryList( array $params ) {
 604                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 605                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 606         }
 607
 608         public function getFileList( array $params ) {
 609                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 610                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 611         }
 612
 613         public function clearCache( array $paths = null ) {
 614                 foreach ( $this->backends as $backend ) {
 615                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 616                         $backend->clearCache( $realPaths );
 617                 }
 618         }
 619
 620         public function getScopedLocksForOps( array $ops, Status $status ) {
 621                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 622                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 623                 // Get the paths to lock from the master backend
 624                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 625                 // Get the paths under the proxy backend's name
 626                 $pbPaths = array(
 627                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 628                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 629                 );
 630                 // Actually acquire the locks
 631                 return array( $this->getScopedFileLocks( $pbPaths, 'mixed', $status ) );
 632         }
 633 }