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, starting with the master.
  37  * This makes a best-effort to have transactional semantics, but since requests
  38  * may sometimes fail, the use of "autoResync" or background scripts to fix
  39  * inconsistencies is important.
  40  *
  41  * @ingroup FileBackend
  42  * @since 1.19
  43  */
  44 class FileBackendMultiWrite extends FileBackend {
  45         /** @var FileBackendStore[] Prioritized list of FileBackendStore objects */
  46         protected $backends = array();
  47
  48         /** @var int Index of master backend */
  49         protected $masterIndex = -1;
  50
  51         /** @var int Bitfield */
  52         protected $syncChecks = 0;
  53
  54         /** @var string|bool */
  55         protected $autoResync = false;
  56
  57         /* Possible internal backend consistency checks */
  58         const CHECK_SIZE = 1;
  59         const CHECK_TIME = 2;
  60         const CHECK_SHA1 = 4;
  61
  62         /**
  63          * Construct a proxy backend that consists of several internal backends.
  64          * Locking, journaling, and read-only checks are handled by the proxy backend.
  65          *
  66          * Additional $config params include:
  67          *   - backends       : Array of backend config and multi-backend settings.
  68          *                      Each value is the config used in the constructor of a
  69          *                      FileBackendStore class, but with these additional settings:
  70          *                        - class         : The name of the backend class
  71          *                        - isMultiMaster : This must be set for one backend.
  72          *                        - template:     : If given a backend name, this will use
  73          *                                          the config of that backend as a template.
  74          *                                          Values specified here take precedence.
  75          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  76          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  77          *                      There are constants for SIZE, TIME, and SHA1.
  78          *                      The checks are done before allowing any file operations.
  79          *   - autoResync     : Automatically resync the clone backends to the master backend
  80          *                      when pre-operation sync checks fail. This should only be used
  81          *                      if the master backend is stable and not missing any files.
  82          *                      Use "conservative" to limit resyncing to copying newer master
  83          *                      backend files over older (or non-existing) clone backend files.
  84          *                      Cases that cannot be handled will result in operation abortion.
  85          *
  86          * @param array $config
  87          * @throws FileBackendError
  88          */
  89         public function __construct( array $config ) {
  90                 parent::__construct( $config );
  91                 $this->syncChecks = isset( $config['syncChecks'] )
  92                         ? $config['syncChecks']
  93                         : self::CHECK_SIZE;
  94                 $this->autoResync = isset( $config['autoResync'] )
  95                         ? $config['autoResync']
  96                         : false;
  97                 // Construct backends here rather than via registration
  98                 // to keep these backends hidden from outside the proxy.
  99                 $namesUsed = array();
 100                 foreach ( $config['backends'] as $index => $config ) {
 101                         if ( isset( $config['template'] ) ) {
 102                                 // Config is just a modified version of a registered backend's.
 103                                 // This should only be used when that config is used only by this backend.
 104                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
 105                         }
 106                         $name = $config['name'];
 107                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 108                                 throw new FileBackendError( "Two or more backends defined with the name $name." );
 109                         }
 110                         $namesUsed[$name] = 1;
 111                         // Alter certain sub-backend settings for sanity
 112                         unset( $config['readOnly'] ); // use proxy backend setting
 113                         unset( $config['fileJournal'] ); // use proxy backend journal
 114                         unset( $config['lockManager'] ); // lock under proxy backend
 115                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
 116                         if ( !empty( $config['isMultiMaster'] ) ) {
 117                                 if ( $this->masterIndex >= 0 ) {
 118                                         throw new FileBackendError( 'More than one master backend defined.' );
 119                                 }
 120                                 $this->masterIndex = $index; // this is the "master"
 121                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 122                         }
 123                         // Create sub-backend object
 124                         if ( !isset( $config['class'] ) ) {
 125                                 throw new FileBackendError( 'No class given for a backend config.' );
 126                         }
 127                         $class = $config['class'];
 128                         $this->backends[$index] = new $class( $config );
 129                 }
 130                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 131                         throw new FileBackendError( 'No master backend defined.' );
 132                 }
 133         }
 134
 135         final protected function doOperationsInternal( array $ops, array $opts ) {
 136                 $status = Status::newGood();
 137
 138                 $mbe = $this->backends[$this->masterIndex]; // convenience
 139
 140                 // Try to lock those files for the scope of this function...
 141                 if ( empty( $opts['nonLocking'] ) ) {
 142                         // Try to lock those files for the scope of this function...
 143                         /** @noinspection PhpUnusedLocalVariableInspection */
 144                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 145                         if ( !$status->isOK() ) {
 146                                 return $status; // abort
 147                         }
 148                 }
 149                 // Clear any cache entries (after locks acquired)
 150                 $this->clearCache();
 151                 $opts['preserveCache'] = true; // only locked files are cached
 152                 // Get the list of paths to read/write...
 153                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 154                 // Check if the paths are valid and accessible on all backends...
 155                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 156                 if ( !$status->isOK() ) {
 157                         return $status; // abort
 158                 }
 159                 // Do a consistency check to see if the backends are consistent...
 160                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 161                 if ( !$syncStatus->isOK() ) {
 162                         wfDebugLog( 'FileOperation', get_class( $this ) .
 163                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 164                         // Try to resync the clone backends to the master on the spot...
 165                         if ( !$this->autoResync || !$this->resyncFiles( $relevantPaths )->isOK() ) {
 166                                 $status->merge( $syncStatus );
 167
 168                                 return $status; // abort
 169                         }
 170                 }
 171                 // Actually attempt the operation batch on the master backend...
 172                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 173                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 174                 $status->merge( $masterStatus );
 175                 // Propagate the operations to the clone backends if there were no unexpected errors
 176                 // and if there were either no expected errors or if the 'force' option was used.
 177                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 178                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 179                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 180                         foreach ( $this->backends as $index => $backend ) {
 181                                 if ( $index !== $this->masterIndex ) { // not done already
 182                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 183                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 184                                 }
 185                         }
 186                 }
 187                 // Make 'success', 'successCount', and 'failCount' fields reflect
 188                 // the overall operation, rather than all the batches for each backend.
 189                 // Do this by only using success values from the master backend's batch.
 190                 $status->success = $masterStatus->success;
 191                 $status->successCount = $masterStatus->successCount;
 192                 $status->failCount = $masterStatus->failCount;
 193
 194                 return $status;
 195         }
 196
 197         /**
 198          * Check that a set of files are consistent across all internal backends
 199          *
 200          * @param array $paths List of storage paths
 201          * @return Status
 202          */
 203         public function consistencyCheck( array $paths ) {
 204                 $status = Status::newGood();
 205                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 206                         return $status; // skip checks
 207                 }
 208
 209                 $mBackend = $this->backends[$this->masterIndex];
 210                 foreach ( $paths as $path ) {
 211                         $params = array( 'src' => $path, 'latest' => true );
 212                         $mParams = $this->substOpPaths( $params, $mBackend );
 213                         // Stat the file on the 'master' backend
 214                         $mStat = $mBackend->getFileStat( $mParams );
 215                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 216                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 217                         } else {
 218                                 $mSha1 = false;
 219                         }
 220                         // Check if all clone backends agree with the master...
 221                         foreach ( $this->backends as $index => $cBackend ) {
 222                                 if ( $index === $this->masterIndex ) {
 223                                         continue; // master
 224                                 }
 225                                 $cParams = $this->substOpPaths( $params, $cBackend );
 226                                 $cStat = $cBackend->getFileStat( $cParams );
 227                                 if ( $mStat ) { // file is in master
 228                                         if ( !$cStat ) { // file should exist
 229                                                 $status->fatal( 'backend-fail-synced', $path );
 230                                                 continue;
 231                                         }
 232                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 233                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 234                                                         $status->fatal( 'backend-fail-synced', $path );
 235                                                         continue;
 236                                                 }
 237                                         }
 238                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 239                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 240                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 241                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 242                                                         $status->fatal( 'backend-fail-synced', $path );
 243                                                         continue;
 244                                                 }
 245                                         }
 246                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 247                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 248                                                         $status->fatal( 'backend-fail-synced', $path );
 249                                                         continue;
 250                                                 }
 251                                         }
 252                                 } else { // file is not in master
 253                                         if ( $cStat ) { // file should not exist
 254                                                 $status->fatal( 'backend-fail-synced', $path );
 255                                         }
 256                                 }
 257                         }
 258                 }
 259
 260                 return $status;
 261         }
 262
 263         /**
 264          * Check that a set of file paths are usable across all internal backends
 265          *
 266          * @param array $paths List of storage paths
 267          * @return Status
 268          */
 269         public function accessibilityCheck( array $paths ) {
 270                 $status = Status::newGood();
 271                 if ( count( $this->backends ) <= 1 ) {
 272                         return $status; // skip checks
 273                 }
 274
 275                 foreach ( $paths as $path ) {
 276                         foreach ( $this->backends as $backend ) {
 277                                 $realPath = $this->substPaths( $path, $backend );
 278                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 279                                         $status->fatal( 'backend-fail-usable', $path );
 280                                 }
 281                         }
 282                 }
 283
 284                 return $status;
 285         }
 286
 287         /**
 288          * Check that a set of files are consistent across all internal backends
 289          * and re-synchronize those files against the "multi master" if needed.
 290          *
 291          * @param array $paths List of storage paths
 292          * @return Status
 293          */
 294         public function resyncFiles( array $paths ) {
 295                 $status = Status::newGood();
 296
 297                 $mBackend = $this->backends[$this->masterIndex];
 298                 foreach ( $paths as $path ) {
 299                         $mPath = $this->substPaths( $path, $mBackend );
 300                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 301                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 302                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 303                                 $status->fatal( 'backend-fail-internal', $this->name );
 304                                 wfDebugLog( 'FileOperation', __METHOD__
 305                                         . ': File is not available on the master backend' );
 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                                         wfDebugLog( 'FileOperation', __METHOD__ .
 319                                                 ': File is not available on the clone backend' );
 320                                         continue; // file is not available on the clone backend...
 321                                 }
 322                                 if ( $mSha1 === $cSha1 ) {
 323                                         // already synced; nothing to do
 324                                 } elseif ( $mSha1 !== false ) { // file is in master
 325                                         if ( $this->autoResync === 'conservative'
 326                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 327                                         ) {
 328                                                 $status->fatal( 'backend-fail-synced', $path );
 329                                                 continue; // don't rollback data
 330                                         }
 331                                         $fsFile = $mBackend->getLocalReference(
 332                                                 array( 'src' => $mPath, 'latest' => true ) );
 333                                         $status->merge( $cBackend->quickStore(
 334                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 335                                         ) );
 336                                 } elseif ( $mStat === false ) { // file is not in master
 337                                         if ( $this->autoResync === 'conservative' ) {
 338                                                 $status->fatal( 'backend-fail-synced', $path );
 339                                                 continue; // don't delete data
 340                                         }
 341                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 342                                 }
 343                         }
 344                 }
 345
 346                 return $status;
 347         }
 348
 349         /**
 350          * Get a list of file storage paths to read or write for a list of operations
 351          *
 352          * @param array $ops Same format as doOperations()
 353          * @return array List of storage paths to files (does not include directories)
 354          */
 355         protected function fileStoragePathsForOps( array $ops ) {
 356                 $paths = array();
 357                 foreach ( $ops as $op ) {
 358                         if ( isset( $op['src'] ) ) {
 359                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 360                                 // is no source file, nothing should happen and there should be no errors.
 361                                 if ( empty( $op['ignoreMissingSource'] )
 362                                         || $this->fileExists( array( 'src' => $op['src'] ) )
 363                                 ) {
 364                                         $paths[] = $op['src'];
 365                                 }
 366                         }
 367                         if ( isset( $op['srcs'] ) ) {
 368                                 $paths = array_merge( $paths, $op['srcs'] );
 369                         }
 370                         if ( isset( $op['dst'] ) ) {
 371                                 $paths[] = $op['dst'];
 372                         }
 373                 }
 374
 375                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 376         }
 377
 378         /**
 379          * Substitute the backend name in storage path parameters
 380          * for a set of operations with that of a given internal backend.
 381          *
 382          * @param array $ops List of file operation arrays
 383          * @param FileBackendStore $backend
 384          * @return array
 385          */
 386         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 387                 $newOps = array(); // operations
 388                 foreach ( $ops as $op ) {
 389                         $newOp = $op; // operation
 390                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 391                                 if ( isset( $newOp[$par] ) ) { // string or array
 392                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 393                                 }
 394                         }
 395                         $newOps[] = $newOp;
 396                 }
 397
 398                 return $newOps;
 399         }
 400
 401         /**
 402          * Same as substOpBatchPaths() but for a single operation
 403          *
 404          * @param array $ops File operation array
 405          * @param FileBackendStore $backend
 406          * @return array
 407          */
 408         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 409                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 410
 411                 return $newOps[0];
 412         }
 413
 414         /**
 415          * Substitute the backend of storage paths with an internal backend's name
 416          *
 417          * @param array|string $paths List of paths or single string path
 418          * @param FileBackendStore $backend
 419          * @return array|string
 420          */
 421         protected function substPaths( $paths, FileBackendStore $backend ) {
 422                 return preg_replace(
 423                         '!^mwstore://' . preg_quote( $this->name, '!' ) . '/!',
 424                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 425                         $paths // string or array
 426                 );
 427         }
 428
 429         /**
 430          * Substitute the backend of internal storage paths with the proxy backend's name
 431          *
 432          * @param array|string $paths List of paths or single string path
 433          * @return array|string
 434          */
 435         protected function unsubstPaths( $paths ) {
 436                 return preg_replace(
 437                         '!^mwstore://([^/]+)!',
 438                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 439                         $paths // string or array
 440                 );
 441         }
 442
 443         protected function doQuickOperationsInternal( array $ops ) {
 444                 $status = Status::newGood();
 445                 // Do the operations on the master backend; setting Status fields...
 446                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 447                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 448                 $status->merge( $masterStatus );
 449                 // Propagate the operations to the clone backends...
 450                 foreach ( $this->backends as $index => $backend ) {
 451                         if ( $index !== $this->masterIndex ) { // not done already
 452                                 $realOps = $this->substOpBatchPaths( $ops, $backend );
 453                                 $status->merge( $backend->doQuickOperations( $realOps ) );
 454                         }
 455                 }
 456                 // Make 'success', 'successCount', and 'failCount' fields reflect
 457                 // the overall operation, rather than all the batches for each backend.
 458                 // Do this by only using success values from the master backend's batch.
 459                 $status->success = $masterStatus->success;
 460                 $status->successCount = $masterStatus->successCount;
 461                 $status->failCount = $masterStatus->failCount;
 462
 463                 return $status;
 464         }
 465
 466         protected function doPrepare( array $params ) {
 467                 $status = Status::newGood();
 468                 foreach ( $this->backends as $index => $backend ) {
 469                         $realParams = $this->substOpPaths( $params, $backend );
 470                         $status->merge( $backend->doPrepare( $realParams ) );
 471                 }
 472
 473                 return $status;
 474         }
 475
 476         protected function doSecure( array $params ) {
 477                 $status = Status::newGood();
 478                 foreach ( $this->backends as $index => $backend ) {
 479                         $realParams = $this->substOpPaths( $params, $backend );
 480                         $status->merge( $backend->doSecure( $realParams ) );
 481                 }
 482
 483                 return $status;
 484         }
 485
 486         protected function doPublish( array $params ) {
 487                 $status = Status::newGood();
 488                 foreach ( $this->backends as $index => $backend ) {
 489                         $realParams = $this->substOpPaths( $params, $backend );
 490                         $status->merge( $backend->doPublish( $realParams ) );
 491                 }
 492
 493                 return $status;
 494         }
 495
 496         protected function doClean( array $params ) {
 497                 $status = Status::newGood();
 498                 foreach ( $this->backends as $index => $backend ) {
 499                         $realParams = $this->substOpPaths( $params, $backend );
 500                         $status->merge( $backend->doClean( $realParams ) );
 501                 }
 502
 503                 return $status;
 504         }
 505
 506         public function concatenate( array $params ) {
 507                 // We are writing to an FS file, so we don't need to do this per-backend
 508                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 509
 510                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 511         }
 512
 513         public function fileExists( array $params ) {
 514                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 515
 516                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 517         }
 518
 519         public function getFileTimestamp( array $params ) {
 520                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 521
 522                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 523         }
 524
 525         public function getFileSize( array $params ) {
 526                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 527
 528                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 529         }
 530
 531         public function getFileStat( array $params ) {
 532                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 533
 534                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 535         }
 536
 537         public function getFileXAttributes( array $params ) {
 538                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 539
 540                 return $this->backends[$this->masterIndex]->getFileXAttributes( $realParams );
 541         }
 542
 543         public function getFileContentsMulti( array $params ) {
 544                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 545                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 546
 547                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 548                 foreach ( $contentsM as $path => $data ) {
 549                         $contents[$this->unsubstPaths( $path )] = $data;
 550                 }
 551
 552                 return $contents;
 553         }
 554
 555         public function getFileSha1Base36( array $params ) {
 556                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 557
 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
 564                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 565         }
 566
 567         public function streamFile( array $params ) {
 568                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 569
 570                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 571         }
 572
 573         public function getLocalReferenceMulti( array $params ) {
 574                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 575                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 576
 577                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 578                 foreach ( $fsFilesM as $path => $fsFile ) {
 579                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 580                 }
 581
 582                 return $fsFiles;
 583         }
 584
 585         public function getLocalCopyMulti( array $params ) {
 586                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 587                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 588
 589                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 590                 foreach ( $tempFilesM as $path => $tempFile ) {
 591                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 592                 }
 593
 594                 return $tempFiles;
 595         }
 596
 597         public function getFileHttpUrl( array $params ) {
 598                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 599
 600                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 601         }
 602
 603         public function directoryExists( array $params ) {
 604                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 605
 606                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 607         }
 608
 609         public function getDirectoryList( array $params ) {
 610                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 611
 612                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 613         }
 614
 615         public function getFileList( array $params ) {
 616                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 617
 618                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 619         }
 620
 621         public function getFeatures() {
 622                 return $this->backends[$this->masterIndex]->getFeatures();
 623         }
 624
 625         public function clearCache( array $paths = null ) {
 626                 foreach ( $this->backends as $backend ) {
 627                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 628                         $backend->clearCache( $realPaths );
 629                 }
 630         }
 631
 632         public function preloadCache( array $paths ) {
 633                 $realPaths = $this->substPaths( $paths, $this->backends[$this->masterIndex] );
 634                 $this->backends[$this->masterIndex]->preloadCache( $realPaths );
 635         }
 636
 637         public function preloadFileStat( array $params ) {
 638                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 639                 return $this->backends[$this->masterIndex]->preloadFileStat( $realParams );
 640         }
 641
 642         public function getScopedLocksForOps( array $ops, Status $status ) {
 643                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 644                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 645                 // Get the paths to lock from the master backend
 646                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 647                 // Get the paths under the proxy backend's name
 648                 $pbPaths = array(
 649                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 650                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 651                 );
 652
 653                 // Actually acquire the locks
 654                 return $this->getScopedFileLocks( $pbPaths, 'mixed', $status );
 655         }
 656 }