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
 171                                 return $status; // abort
 172                         }
 173                 }
 174                 // Actually attempt the operation batch on the master backend...
 175                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 176                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 177                 $status->merge( $masterStatus );
 178                 // Propagate the operations to the clone backends if there were no unexpected errors
 179                 // and if there were either no expected errors or if the 'force' option was used.
 180                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 181                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 182                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 183                         foreach ( $this->backends as $index => $backend ) {
 184                                 if ( $index !== $this->masterIndex ) { // not done already
 185                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 186                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 187                                 }
 188                         }
 189                 }
 190                 // Make 'success', 'successCount', and 'failCount' fields reflect
 191                 // the overall operation, rather than all the batches for each backend.
 192                 // Do this by only using success values from the master backend's batch.
 193                 $status->success = $masterStatus->success;
 194                 $status->successCount = $masterStatus->successCount;
 195                 $status->failCount = $masterStatus->failCount;
 196
 197                 return $status;
 198         }
 199
 200         /**
 201          * Check that a set of files are consistent across all internal backends
 202          *
 203          * @param array $paths List of storage paths
 204          * @return Status
 205          */
 206         public function consistencyCheck( array $paths ) {
 207                 $status = Status::newGood();
 208                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 209                         return $status; // skip checks
 210                 }
 211
 212                 $mBackend = $this->backends[$this->masterIndex];
 213                 foreach ( $paths as $path ) {
 214                         $params = array( 'src' => $path, 'latest' => true );
 215                         $mParams = $this->substOpPaths( $params, $mBackend );
 216                         // Stat the file on the 'master' backend
 217                         $mStat = $mBackend->getFileStat( $mParams );
 218                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 219                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 220                         } else {
 221                                 $mSha1 = false;
 222                         }
 223                         // Check if all clone backends agree with the master...
 224                         foreach ( $this->backends as $index => $cBackend ) {
 225                                 if ( $index === $this->masterIndex ) {
 226                                         continue; // master
 227                                 }
 228                                 $cParams = $this->substOpPaths( $params, $cBackend );
 229                                 $cStat = $cBackend->getFileStat( $cParams );
 230                                 if ( $mStat ) { // file is in master
 231                                         if ( !$cStat ) { // file should exist
 232                                                 $status->fatal( 'backend-fail-synced', $path );
 233                                                 continue;
 234                                         }
 235                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 236                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 237                                                         $status->fatal( 'backend-fail-synced', $path );
 238                                                         continue;
 239                                                 }
 240                                         }
 241                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 242                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 243                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 244                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 245                                                         $status->fatal( 'backend-fail-synced', $path );
 246                                                         continue;
 247                                                 }
 248                                         }
 249                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 250                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 251                                                         $status->fatal( 'backend-fail-synced', $path );
 252                                                         continue;
 253                                                 }
 254                                         }
 255                                 } else { // file is not in master
 256                                         if ( $cStat ) { // file should not exist
 257                                                 $status->fatal( 'backend-fail-synced', $path );
 258                                         }
 259                                 }
 260                         }
 261                 }
 262
 263                 return $status;
 264         }
 265
 266         /**
 267          * Check that a set of file paths are usable across all internal backends
 268          *
 269          * @param array $paths List of storage paths
 270          * @return Status
 271          */
 272         public function accessibilityCheck( array $paths ) {
 273                 $status = Status::newGood();
 274                 if ( count( $this->backends ) <= 1 ) {
 275                         return $status; // skip checks
 276                 }
 277
 278                 foreach ( $paths as $path ) {
 279                         foreach ( $this->backends as $backend ) {
 280                                 $realPath = $this->substPaths( $path, $backend );
 281                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 282                                         $status->fatal( 'backend-fail-usable', $path );
 283                                 }
 284                         }
 285                 }
 286
 287                 return $status;
 288         }
 289
 290         /**
 291          * Check that a set of files are consistent across all internal backends
 292          * and re-synchronize those files againt the "multi master" if needed.
 293          *
 294          * @param array $paths List of storage paths
 295          * @return Status
 296          */
 297         public function resyncFiles( array $paths ) {
 298                 $status = Status::newGood();
 299
 300                 $mBackend = $this->backends[$this->masterIndex];
 301                 foreach ( $paths as $path ) {
 302                         $mPath = $this->substPaths( $path, $mBackend );
 303                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 304                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 305                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 306                                 $status->fatal( 'backend-fail-internal', $this->name );
 307                                 continue; // file is not available on the master backend...
 308                         }
 309                         // Check of all clone backends agree with the master...
 310                         foreach ( $this->backends as $index => $cBackend ) {
 311                                 if ( $index === $this->masterIndex ) {
 312                                         continue; // master
 313                                 }
 314                                 $cPath = $this->substPaths( $path, $cBackend );
 315                                 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath, 'latest' => true ) );
 316                                 $cStat = $cBackend->getFileStat( array( 'src' => $cPath, 'latest' => true ) );
 317                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 318                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 319                                         continue; // file is not available on the clone backend...
 320                                 }
 321                                 if ( $mSha1 === $cSha1 ) {
 322                                         // already synced; nothing to do
 323                                 } elseif ( $mSha1 !== false ) { // file is in master
 324                                         if ( $this->autoResync === 'conservative'
 325                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 326                                         ) {
 327                                                 $status->fatal( 'backend-fail-synced', $path );
 328                                                 continue; // don't rollback data
 329                                         }
 330                                         $fsFile = $mBackend->getLocalReference(
 331                                                 array( 'src' => $mPath, 'latest' => true ) );
 332                                         $status->merge( $cBackend->quickStore(
 333                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 334                                         ) );
 335                                 } elseif ( $mStat === false ) { // file is not in master
 336                                         if ( $this->autoResync === 'conservative' ) {
 337                                                 $status->fatal( 'backend-fail-synced', $path );
 338                                                 continue; // don't delete data
 339                                         }
 340                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 341                                 }
 342                         }
 343                 }
 344
 345                 return $status;
 346         }
 347
 348         /**
 349          * Get a list of file storage paths to read or write for a list of operations
 350          *
 351          * @param array $ops Same format as doOperations()
 352          * @return Array List of storage paths to files (does not include directories)
 353          */
 354         protected function fileStoragePathsForOps( array $ops ) {
 355                 $paths = array();
 356                 foreach ( $ops as $op ) {
 357                         if ( isset( $op['src'] ) ) {
 358                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 359                                 // is no source file, nothing should happen and there should be no errors.
 360                                 if ( empty( $op['ignoreMissingSource'] )
 361                                         || $this->fileExists( array( 'src' => $op['src'] ) )
 362                                 ) {
 363                                         $paths[] = $op['src'];
 364                                 }
 365                         }
 366                         if ( isset( $op['srcs'] ) ) {
 367                                 $paths = array_merge( $paths, $op['srcs'] );
 368                         }
 369                         if ( isset( $op['dst'] ) ) {
 370                                 $paths[] = $op['dst'];
 371                         }
 372                 }
 373
 374                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 375         }
 376
 377         /**
 378          * Substitute the backend name in storage path parameters
 379          * for a set of operations with that of a given internal backend.
 380          *
 381          * @param array $ops List of file operation arrays
 382          * @param FileBackendStore $backend
 383          * @return Array
 384          */
 385         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 386                 $newOps = array(); // operations
 387                 foreach ( $ops as $op ) {
 388                         $newOp = $op; // operation
 389                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 390                                 if ( isset( $newOp[$par] ) ) { // string or array
 391                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 392                                 }
 393                         }
 394                         $newOps[] = $newOp;
 395                 }
 396
 397                 return $newOps;
 398         }
 399
 400         /**
 401          * Same as substOpBatchPaths() but for a single operation
 402          *
 403          * @param array $ops File operation array
 404          * @param FileBackendStore $backend
 405          * @return Array
 406          */
 407         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 408                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 409
 410                 return $newOps[0];
 411         }
 412
 413         /**
 414          * Substitute the backend of storage paths with an internal backend's name
 415          *
 416          * @param array|string $paths List of paths or single string path
 417          * @param FileBackendStore $backend
 418          * @return Array|string
 419          */
 420         protected function substPaths( $paths, FileBackendStore $backend ) {
 421                 return preg_replace(
 422                         '!^mwstore://' . preg_quote( $this->name ) . '/!',
 423                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 424                         $paths // string or array
 425                 );
 426         }
 427
 428         /**
 429          * Substitute the backend of internal storage paths with the proxy backend's name
 430          *
 431          * @param array|string $paths List of paths or single string path
 432          * @return Array|string
 433          */
 434         protected function unsubstPaths( $paths ) {
 435                 return preg_replace(
 436                         '!^mwstore://([^/]+)!',
 437                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 438                         $paths // string or array
 439                 );
 440         }
 441
 442         protected function doQuickOperationsInternal( array $ops ) {
 443                 $status = Status::newGood();
 444                 // Do the operations on the master backend; setting Status fields...
 445                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 446                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 447                 $status->merge( $masterStatus );
 448                 // Propagate the operations to the clone backends...
 449                 if ( !$this->noPushQuickOps ) {
 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                 }
 457                 // Make 'success', 'successCount', and 'failCount' fields reflect
 458                 // the overall operation, rather than all the batches for each backend.
 459                 // Do this by only using success values from the master backend's batch.
 460                 $status->success = $masterStatus->success;
 461                 $status->successCount = $masterStatus->successCount;
 462                 $status->failCount = $masterStatus->failCount;
 463
 464                 return $status;
 465         }
 466
 467         /**
 468          * @param string $path Storage path
 469          * @return bool Path container should have dir changes pushed to all backends
 470          */
 471         protected function replicateContainerDirChanges( $path ) {
 472                 list( , $shortCont, ) = self::splitStoragePath( $path );
 473
 474                 return !in_array( $shortCont, $this->noPushDirConts );
 475         }
 476
 477         protected function doPrepare( array $params ) {
 478                 $status = Status::newGood();
 479                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 480                 foreach ( $this->backends as $index => $backend ) {
 481                         if ( $replicate || $index == $this->masterIndex ) {
 482                                 $realParams = $this->substOpPaths( $params, $backend );
 483                                 $status->merge( $backend->doPrepare( $realParams ) );
 484                         }
 485                 }
 486
 487                 return $status;
 488         }
 489
 490         protected function doSecure( array $params ) {
 491                 $status = Status::newGood();
 492                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 493                 foreach ( $this->backends as $index => $backend ) {
 494                         if ( $replicate || $index == $this->masterIndex ) {
 495                                 $realParams = $this->substOpPaths( $params, $backend );
 496                                 $status->merge( $backend->doSecure( $realParams ) );
 497                         }
 498                 }
 499
 500                 return $status;
 501         }
 502
 503         protected function doPublish( array $params ) {
 504                 $status = Status::newGood();
 505                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 506                 foreach ( $this->backends as $index => $backend ) {
 507                         if ( $replicate || $index == $this->masterIndex ) {
 508                                 $realParams = $this->substOpPaths( $params, $backend );
 509                                 $status->merge( $backend->doPublish( $realParams ) );
 510                         }
 511                 }
 512
 513                 return $status;
 514         }
 515
 516         protected function doClean( array $params ) {
 517                 $status = Status::newGood();
 518                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 519                 foreach ( $this->backends as $index => $backend ) {
 520                         if ( $replicate || $index == $this->masterIndex ) {
 521                                 $realParams = $this->substOpPaths( $params, $backend );
 522                                 $status->merge( $backend->doClean( $realParams ) );
 523                         }
 524                 }
 525
 526                 return $status;
 527         }
 528
 529         public function concatenate( array $params ) {
 530                 // We are writing to an FS file, so we don't need to do this per-backend
 531                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 532
 533                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 534         }
 535
 536         public function fileExists( array $params ) {
 537                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 538
 539                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 540         }
 541
 542         public function getFileTimestamp( array $params ) {
 543                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 544
 545                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 546         }
 547
 548         public function getFileSize( array $params ) {
 549                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 550
 551                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 552         }
 553
 554         public function getFileStat( array $params ) {
 555                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 556
 557                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 558         }
 559
 560         public function getFileContentsMulti( array $params ) {
 561                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 562                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 563
 564                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 565                 foreach ( $contentsM as $path => $data ) {
 566                         $contents[$this->unsubstPaths( $path )] = $data;
 567                 }
 568
 569                 return $contents;
 570         }
 571
 572         public function getFileSha1Base36( array $params ) {
 573                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 574
 575                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 576         }
 577
 578         public function getFileProps( array $params ) {
 579                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 580
 581                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 582         }
 583
 584         public function streamFile( array $params ) {
 585                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 586
 587                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 588         }
 589
 590         public function getLocalReferenceMulti( array $params ) {
 591                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 592                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 593
 594                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 595                 foreach ( $fsFilesM as $path => $fsFile ) {
 596                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 597                 }
 598
 599                 return $fsFiles;
 600         }
 601
 602         public function getLocalCopyMulti( array $params ) {
 603                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 604                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 605
 606                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 607                 foreach ( $tempFilesM as $path => $tempFile ) {
 608                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 609                 }
 610
 611                 return $tempFiles;
 612         }
 613
 614         public function getFileHttpUrl( array $params ) {
 615                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 616
 617                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 618         }
 619
 620         public function directoryExists( array $params ) {
 621                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 622
 623                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 624         }
 625
 626         public function getDirectoryList( array $params ) {
 627                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 628
 629                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 630         }
 631
 632         public function getFileList( array $params ) {
 633                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 634
 635                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 636         }
 637
 638         public function clearCache( array $paths = null ) {
 639                 foreach ( $this->backends as $backend ) {
 640                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 641                         $backend->clearCache( $realPaths );
 642                 }
 643         }
 644
 645         public function getScopedLocksForOps( array $ops, Status $status ) {
 646                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 647                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 648                 // Get the paths to lock from the master backend
 649                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 650                 // Get the paths under the proxy backend's name
 651                 $pbPaths = array(
 652                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 653                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 654                 );
 655
 656                 // Actually acquire the locks
 657                 return array( $this->getScopedFileLocks( $pbPaths, 'mixed', $status ) );
 658         }
 659 }