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 FileBackendStore[] Prioritized list of FileBackendStore objects */
  44         protected $backends = array();
  45
  46         /** @var int Index of master backend */
  47         protected $masterIndex = -1;
  48
  49         /** @var int Bitfield */
  50         protected $syncChecks = 0;
  51
  52         /** @var string|bool */
  53         protected $autoResync = false;
  54
  55         /** @var array */
  56         protected $noPushDirConts = array();
  57
  58         /** @var bool */
  59         protected $noPushQuickOps = false;
  60
  61         /* Possible internal backend consistency checks */
  62         const CHECK_SIZE = 1;
  63         const CHECK_TIME = 2;
  64         const CHECK_SHA1 = 4;
  65
  66         /**
  67          * Construct a proxy backend that consists of several internal backends.
  68          * Locking, journaling, and read-only checks are handled by the proxy backend.
  69          *
  70          * Additional $config params include:
  71          *   - backends       : Array of backend config and multi-backend settings.
  72          *                      Each value is the config used in the constructor of a
  73          *                      FileBackendStore class, but with these additional settings:
  74          *                        - class         : The name of the backend class
  75          *                        - isMultiMaster : This must be set for one backend.
  76          *                        - template:     : If given a backend name, this will use
  77          *                                          the config of that backend as a template.
  78          *                                          Values specified here take precedence.
  79          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  80          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  81          *                      There are constants for SIZE, TIME, and SHA1.
  82          *                      The checks are done before allowing any file operations.
  83          *   - autoResync     : Automatically resync the clone backends to the master backend
  84          *                      when pre-operation sync checks fail. This should only be used
  85          *                      if the master backend is stable and not missing any files.
  86          *                      Use "conservative" to limit resyncing to copying newer master
  87          *                      backend files over older (or non-existing) clone backend files.
  88          *                      Cases that cannot be handled will result in operation abortion.
  89          *   - noPushQuickOps : (hack) Only apply doQuickOperations() to the master backend.
  90          *   - noPushDirConts : (hack) Only apply directory functions to the master backend.
  91          *
  92          * @param array $config
  93          * @throws FileBackendError
  94          */
  95         public function __construct( array $config ) {
  96                 parent::__construct( $config );
  97                 $this->syncChecks = isset( $config['syncChecks'] )
  98                         ? $config['syncChecks']
  99                         : self::CHECK_SIZE;
 100                 $this->autoResync = isset( $config['autoResync'] )
 101                         ? $config['autoResync']
 102                         : false;
 103                 $this->noPushQuickOps = isset( $config['noPushQuickOps'] )
 104                         ? $config['noPushQuickOps']
 105                         : false;
 106                 $this->noPushDirConts = isset( $config['noPushDirConts'] )
 107                         ? $config['noPushDirConts']
 108                         : array();
 109                 // Construct backends here rather than via registration
 110                 // to keep these backends hidden from outside the proxy.
 111                 $namesUsed = array();
 112                 foreach ( $config['backends'] as $index => $config ) {
 113                         if ( isset( $config['template'] ) ) {
 114                                 // Config is just a modified version of a registered backend's.
 115                                 // This should only be used when that config is used only by this backend.
 116                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
 117                         }
 118                         $name = $config['name'];
 119                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 120                                 throw new FileBackendError( "Two or more backends defined with the name $name." );
 121                         }
 122                         $namesUsed[$name] = 1;
 123                         // Alter certain sub-backend settings for sanity
 124                         unset( $config['readOnly'] ); // use proxy backend setting
 125                         unset( $config['fileJournal'] ); // use proxy backend journal
 126                         unset( $config['lockManager'] ); // lock under proxy backend
 127                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
 128                         if ( !empty( $config['isMultiMaster'] ) ) {
 129                                 if ( $this->masterIndex >= 0 ) {
 130                                         throw new FileBackendError( 'More than one master backend defined.' );
 131                                 }
 132                                 $this->masterIndex = $index; // this is the "master"
 133                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 134                         }
 135                         // Create sub-backend object
 136                         if ( !isset( $config['class'] ) ) {
 137                                 throw new FileBackendError( 'No class given for a backend config.' );
 138                         }
 139                         $class = $config['class'];
 140                         $this->backends[$index] = new $class( $config );
 141                 }
 142                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 143                         throw new FileBackendError( 'No master backend defined.' );
 144                 }
 145         }
 146
 147         final protected function doOperationsInternal( array $ops, array $opts ) {
 148                 $status = Status::newGood();
 149
 150                 $mbe = $this->backends[$this->masterIndex]; // convenience
 151
 152                 // Try to lock those files for the scope of this function...
 153                 if ( empty( $opts['nonLocking'] ) ) {
 154                         // Try to lock those files for the scope of this function...
 155                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 156                         if ( !$status->isOK() ) {
 157                                 return $status; // abort
 158                         }
 159                 }
 160                 // Clear any cache entries (after locks acquired)
 161                 $this->clearCache();
 162                 $opts['preserveCache'] = true; // only locked files are cached
 163                 // Get the list of paths to read/write...
 164                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 165                 // Check if the paths are valid and accessible on all backends...
 166                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 167                 if ( !$status->isOK() ) {
 168                         return $status; // abort
 169                 }
 170                 // Do a consistency check to see if the backends are consistent...
 171                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 172                 if ( !$syncStatus->isOK() ) {
 173                         wfDebugLog( 'FileOperation', get_class( $this ) .
 174                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 175                         // Try to resync the clone backends to the master on the spot...
 176                         if ( !$this->autoResync || !$this->resyncFiles( $relevantPaths )->isOK() ) {
 177                                 $status->merge( $syncStatus );
 178
 179                                 return $status; // abort
 180                         }
 181                 }
 182                 // Actually attempt the operation batch on the master backend...
 183                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 184                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 185                 $status->merge( $masterStatus );
 186                 // Propagate the operations to the clone backends if there were no unexpected errors
 187                 // and if there were either no expected errors or if the 'force' option was used.
 188                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 189                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 190                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 191                         foreach ( $this->backends as $index => $backend ) {
 192                                 if ( $index !== $this->masterIndex ) { // not done already
 193                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 194                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 195                                 }
 196                         }
 197                 }
 198                 // Make 'success', 'successCount', and 'failCount' fields reflect
 199                 // the overall operation, rather than all the batches for each backend.
 200                 // Do this by only using success values from the master backend's batch.
 201                 $status->success = $masterStatus->success;
 202                 $status->successCount = $masterStatus->successCount;
 203                 $status->failCount = $masterStatus->failCount;
 204
 205                 return $status;
 206         }
 207
 208         /**
 209          * Check that a set of files are consistent across all internal backends
 210          *
 211          * @param array $paths List of storage paths
 212          * @return Status
 213          */
 214         public function consistencyCheck( array $paths ) {
 215                 $status = Status::newGood();
 216                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 217                         return $status; // skip checks
 218                 }
 219
 220                 $mBackend = $this->backends[$this->masterIndex];
 221                 foreach ( $paths as $path ) {
 222                         $params = array( 'src' => $path, 'latest' => true );
 223                         $mParams = $this->substOpPaths( $params, $mBackend );
 224                         // Stat the file on the 'master' backend
 225                         $mStat = $mBackend->getFileStat( $mParams );
 226                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 227                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 228                         } else {
 229                                 $mSha1 = false;
 230                         }
 231                         // Check if all clone backends agree with the master...
 232                         foreach ( $this->backends as $index => $cBackend ) {
 233                                 if ( $index === $this->masterIndex ) {
 234                                         continue; // master
 235                                 }
 236                                 $cParams = $this->substOpPaths( $params, $cBackend );
 237                                 $cStat = $cBackend->getFileStat( $cParams );
 238                                 if ( $mStat ) { // file is in master
 239                                         if ( !$cStat ) { // file should exist
 240                                                 $status->fatal( 'backend-fail-synced', $path );
 241                                                 continue;
 242                                         }
 243                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 244                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 245                                                         $status->fatal( 'backend-fail-synced', $path );
 246                                                         continue;
 247                                                 }
 248                                         }
 249                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 250                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 251                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 252                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 253                                                         $status->fatal( 'backend-fail-synced', $path );
 254                                                         continue;
 255                                                 }
 256                                         }
 257                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 258                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 259                                                         $status->fatal( 'backend-fail-synced', $path );
 260                                                         continue;
 261                                                 }
 262                                         }
 263                                 } else { // file is not in master
 264                                         if ( $cStat ) { // file should not exist
 265                                                 $status->fatal( 'backend-fail-synced', $path );
 266                                         }
 267                                 }
 268                         }
 269                 }
 270
 271                 return $status;
 272         }
 273
 274         /**
 275          * Check that a set of file paths are usable across all internal backends
 276          *
 277          * @param array $paths List of storage paths
 278          * @return Status
 279          */
 280         public function accessibilityCheck( array $paths ) {
 281                 $status = Status::newGood();
 282                 if ( count( $this->backends ) <= 1 ) {
 283                         return $status; // skip checks
 284                 }
 285
 286                 foreach ( $paths as $path ) {
 287                         foreach ( $this->backends as $backend ) {
 288                                 $realPath = $this->substPaths( $path, $backend );
 289                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 290                                         $status->fatal( 'backend-fail-usable', $path );
 291                                 }
 292                         }
 293                 }
 294
 295                 return $status;
 296         }
 297
 298         /**
 299          * Check that a set of files are consistent across all internal backends
 300          * and re-synchronize those files against the "multi master" if needed.
 301          *
 302          * @param array $paths List of storage paths
 303          * @return Status
 304          */
 305         public function resyncFiles( array $paths ) {
 306                 $status = Status::newGood();
 307
 308                 $mBackend = $this->backends[$this->masterIndex];
 309                 foreach ( $paths as $path ) {
 310                         $mPath = $this->substPaths( $path, $mBackend );
 311                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 312                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 313                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 314                                 $status->fatal( 'backend-fail-internal', $this->name );
 315                                 wfDebugLog( 'FileOperation', __METHOD__
 316                                         . ': File is not available on the master backend' );
 317                                 continue; // file is not available on the master backend...
 318                         }
 319                         // Check of all clone backends agree with the master...
 320                         foreach ( $this->backends as $index => $cBackend ) {
 321                                 if ( $index === $this->masterIndex ) {
 322                                         continue; // master
 323                                 }
 324                                 $cPath = $this->substPaths( $path, $cBackend );
 325                                 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath, 'latest' => true ) );
 326                                 $cStat = $cBackend->getFileStat( array( 'src' => $cPath, 'latest' => true ) );
 327                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 328                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 329                                         wfDebugLog( 'FileOperation', __METHOD__ .
 330                                                 ': File is not available on the clone backend' );
 331                                         continue; // file is not available on the clone backend...
 332                                 }
 333                                 if ( $mSha1 === $cSha1 ) {
 334                                         // already synced; nothing to do
 335                                 } elseif ( $mSha1 !== false ) { // file is in master
 336                                         if ( $this->autoResync === 'conservative'
 337                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 338                                         ) {
 339                                                 $status->fatal( 'backend-fail-synced', $path );
 340                                                 continue; // don't rollback data
 341                                         }
 342                                         $fsFile = $mBackend->getLocalReference(
 343                                                 array( 'src' => $mPath, 'latest' => true ) );
 344                                         $status->merge( $cBackend->quickStore(
 345                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 346                                         ) );
 347                                 } elseif ( $mStat === false ) { // file is not in master
 348                                         if ( $this->autoResync === 'conservative' ) {
 349                                                 $status->fatal( 'backend-fail-synced', $path );
 350                                                 continue; // don't delete data
 351                                         }
 352                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 353                                 }
 354                         }
 355                 }
 356
 357                 return $status;
 358         }
 359
 360         /**
 361          * Get a list of file storage paths to read or write for a list of operations
 362          *
 363          * @param array $ops Same format as doOperations()
 364          * @return array List of storage paths to files (does not include directories)
 365          */
 366         protected function fileStoragePathsForOps( array $ops ) {
 367                 $paths = array();
 368                 foreach ( $ops as $op ) {
 369                         if ( isset( $op['src'] ) ) {
 370                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 371                                 // is no source file, nothing should happen and there should be no errors.
 372                                 if ( empty( $op['ignoreMissingSource'] )
 373                                         || $this->fileExists( array( 'src' => $op['src'] ) )
 374                                 ) {
 375                                         $paths[] = $op['src'];
 376                                 }
 377                         }
 378                         if ( isset( $op['srcs'] ) ) {
 379                                 $paths = array_merge( $paths, $op['srcs'] );
 380                         }
 381                         if ( isset( $op['dst'] ) ) {
 382                                 $paths[] = $op['dst'];
 383                         }
 384                 }
 385
 386                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 387         }
 388
 389         /**
 390          * Substitute the backend name in storage path parameters
 391          * for a set of operations with that of a given internal backend.
 392          *
 393          * @param array $ops List of file operation arrays
 394          * @param FileBackendStore $backend
 395          * @return array
 396          */
 397         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 398                 $newOps = array(); // operations
 399                 foreach ( $ops as $op ) {
 400                         $newOp = $op; // operation
 401                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 402                                 if ( isset( $newOp[$par] ) ) { // string or array
 403                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 404                                 }
 405                         }
 406                         $newOps[] = $newOp;
 407                 }
 408
 409                 return $newOps;
 410         }
 411
 412         /**
 413          * Same as substOpBatchPaths() but for a single operation
 414          *
 415          * @param array $ops File operation array
 416          * @param FileBackendStore $backend
 417          * @return array
 418          */
 419         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 420                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 421
 422                 return $newOps[0];
 423         }
 424
 425         /**
 426          * Substitute the backend of storage paths with an internal backend's name
 427          *
 428          * @param array|string $paths List of paths or single string path
 429          * @param FileBackendStore $backend
 430          * @return array|string
 431          */
 432         protected function substPaths( $paths, FileBackendStore $backend ) {
 433                 return preg_replace(
 434                         '!^mwstore://' . preg_quote( $this->name, '!' ) . '/!',
 435                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 436                         $paths // string or array
 437                 );
 438         }
 439
 440         /**
 441          * Substitute the backend of internal storage paths with the proxy backend's name
 442          *
 443          * @param array|string $paths List of paths or single string path
 444          * @return array|string
 445          */
 446         protected function unsubstPaths( $paths ) {
 447                 return preg_replace(
 448                         '!^mwstore://([^/]+)!',
 449                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 450                         $paths // string or array
 451                 );
 452         }
 453
 454         protected function doQuickOperationsInternal( array $ops ) {
 455                 $status = Status::newGood();
 456                 // Do the operations on the master backend; setting Status fields...
 457                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 458                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 459                 $status->merge( $masterStatus );
 460                 // Propagate the operations to the clone backends...
 461                 if ( !$this->noPushQuickOps ) {
 462                         foreach ( $this->backends as $index => $backend ) {
 463                                 if ( $index !== $this->masterIndex ) { // not done already
 464                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 465                                         $status->merge( $backend->doQuickOperations( $realOps ) );
 466                                 }
 467                         }
 468                 }
 469                 // Make 'success', 'successCount', and 'failCount' fields reflect
 470                 // the overall operation, rather than all the batches for each backend.
 471                 // Do this by only using success values from the master backend's batch.
 472                 $status->success = $masterStatus->success;
 473                 $status->successCount = $masterStatus->successCount;
 474                 $status->failCount = $masterStatus->failCount;
 475
 476                 return $status;
 477         }
 478
 479         /**
 480          * @param string $path Storage path
 481          * @return bool Path container should have dir changes pushed to all backends
 482          */
 483         protected function replicateContainerDirChanges( $path ) {
 484                 list( , $shortCont, ) = self::splitStoragePath( $path );
 485
 486                 return !in_array( $shortCont, $this->noPushDirConts );
 487         }
 488
 489         protected function doPrepare( array $params ) {
 490                 $status = Status::newGood();
 491                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 492                 foreach ( $this->backends as $index => $backend ) {
 493                         if ( $replicate || $index == $this->masterIndex ) {
 494                                 $realParams = $this->substOpPaths( $params, $backend );
 495                                 $status->merge( $backend->doPrepare( $realParams ) );
 496                         }
 497                 }
 498
 499                 return $status;
 500         }
 501
 502         protected function doSecure( array $params ) {
 503                 $status = Status::newGood();
 504                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 505                 foreach ( $this->backends as $index => $backend ) {
 506                         if ( $replicate || $index == $this->masterIndex ) {
 507                                 $realParams = $this->substOpPaths( $params, $backend );
 508                                 $status->merge( $backend->doSecure( $realParams ) );
 509                         }
 510                 }
 511
 512                 return $status;
 513         }
 514
 515         protected function doPublish( array $params ) {
 516                 $status = Status::newGood();
 517                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 518                 foreach ( $this->backends as $index => $backend ) {
 519                         if ( $replicate || $index == $this->masterIndex ) {
 520                                 $realParams = $this->substOpPaths( $params, $backend );
 521                                 $status->merge( $backend->doPublish( $realParams ) );
 522                         }
 523                 }
 524
 525                 return $status;
 526         }
 527
 528         protected function doClean( array $params ) {
 529                 $status = Status::newGood();
 530                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 531                 foreach ( $this->backends as $index => $backend ) {
 532                         if ( $replicate || $index == $this->masterIndex ) {
 533                                 $realParams = $this->substOpPaths( $params, $backend );
 534                                 $status->merge( $backend->doClean( $realParams ) );
 535                         }
 536                 }
 537
 538                 return $status;
 539         }
 540
 541         public function concatenate( array $params ) {
 542                 // We are writing to an FS file, so we don't need to do this per-backend
 543                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 544
 545                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 546         }
 547
 548         public function fileExists( array $params ) {
 549                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 550
 551                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 552         }
 553
 554         public function getFileTimestamp( array $params ) {
 555                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 556
 557                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 558         }
 559
 560         public function getFileSize( array $params ) {
 561                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 562
 563                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 564         }
 565
 566         public function getFileStat( array $params ) {
 567                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 568
 569                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 570         }
 571
 572         public function getFileXAttributes( array $params ) {
 573                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 574
 575                 return $this->backends[$this->masterIndex]->getFileXAttributes( $realParams );
 576         }
 577
 578         public function getFileContentsMulti( array $params ) {
 579                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 580                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 581
 582                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 583                 foreach ( $contentsM as $path => $data ) {
 584                         $contents[$this->unsubstPaths( $path )] = $data;
 585                 }
 586
 587                 return $contents;
 588         }
 589
 590         public function getFileSha1Base36( array $params ) {
 591                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 592
 593                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 594         }
 595
 596         public function getFileProps( array $params ) {
 597                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 598
 599                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 600         }
 601
 602         public function streamFile( array $params ) {
 603                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 604
 605                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 606         }
 607
 608         public function getLocalReferenceMulti( array $params ) {
 609                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 610                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 611
 612                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 613                 foreach ( $fsFilesM as $path => $fsFile ) {
 614                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 615                 }
 616
 617                 return $fsFiles;
 618         }
 619
 620         public function getLocalCopyMulti( array $params ) {
 621                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 622                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 623
 624                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 625                 foreach ( $tempFilesM as $path => $tempFile ) {
 626                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 627                 }
 628
 629                 return $tempFiles;
 630         }
 631
 632         public function getFileHttpUrl( array $params ) {
 633                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 634
 635                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 636         }
 637
 638         public function directoryExists( array $params ) {
 639                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 640
 641                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 642         }
 643
 644         public function getDirectoryList( array $params ) {
 645                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 646
 647                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 648         }
 649
 650         public function getFileList( array $params ) {
 651                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 652
 653                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 654         }
 655
 656         public function getFeatures() {
 657                 return $this->backends[$this->masterIndex]->getFeatures();
 658         }
 659
 660         public function clearCache( array $paths = null ) {
 661                 foreach ( $this->backends as $backend ) {
 662                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 663                         $backend->clearCache( $realPaths );
 664                 }
 665         }
 666
 667         public function preloadCache( array $paths ) {
 668                 $realPaths = $this->substPaths( $paths, $this->backends[$this->masterIndex] );
 669                 $this->backends[$this->masterIndex]->preloadCache( $realPaths );
 670         }
 671
 672         public function preloadFileStat( array $params ) {
 673                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 674                 return $this->backends[$this->masterIndex]->preloadFileStat( $realParams );
 675         }
 676
 677         public function getScopedLocksForOps( array $ops, Status $status ) {
 678                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 679                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 680                 // Get the paths to lock from the master backend
 681                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 682                 // Get the paths under the proxy backend's name
 683                 $pbPaths = array(
 684                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 685                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 686                 );
 687
 688                 // Actually acquire the locks
 689                 return $this->getScopedFileLocks( $pbPaths, 'mixed', $status );
 690         }
 691 }