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         /** @var array */
  58         protected $noPushDirConts = array();
  59
  60         /** @var bool */
  61         protected $noPushQuickOps = false;
  62
  63         /* Possible internal backend consistency checks */
  64         const CHECK_SIZE = 1;
  65         const CHECK_TIME = 2;
  66         const CHECK_SHA1 = 4;
  67
  68         /**
  69          * Construct a proxy backend that consists of several internal backends.
  70          * Locking, journaling, and read-only checks are handled by the proxy backend.
  71          *
  72          * Additional $config params include:
  73          *   - backends       : Array of backend config and multi-backend settings.
  74          *                      Each value is the config used in the constructor of a
  75          *                      FileBackendStore class, but with these additional settings:
  76          *                        - class         : The name of the backend class
  77          *                        - isMultiMaster : This must be set for one backend.
  78          *                        - template:     : If given a backend name, this will use
  79          *                                          the config of that backend as a template.
  80          *                                          Values specified here take precedence.
  81          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  82          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  83          *                      There are constants for SIZE, TIME, and SHA1.
  84          *                      The checks are done before allowing any file operations.
  85          *   - autoResync     : Automatically resync the clone backends to the master backend
  86          *                      when pre-operation sync checks fail. This should only be used
  87          *                      if the master backend is stable and not missing any files.
  88          *                      Use "conservative" to limit resyncing to copying newer master
  89          *                      backend files over older (or non-existing) clone backend files.
  90          *                      Cases that cannot be handled will result in operation abortion.
  91          *   - noPushQuickOps : (hack) Only apply doQuickOperations() to the master backend.
  92          *   - noPushDirConts : (hack) Only apply directory functions to the master backend.
  93          *
  94          * @param array $config
  95          * @throws FileBackendError
  96          */
  97         public function __construct( array $config ) {
  98                 parent::__construct( $config );
  99                 $this->syncChecks = isset( $config['syncChecks'] )
 100                         ? $config['syncChecks']
 101                         : self::CHECK_SIZE;
 102                 $this->autoResync = isset( $config['autoResync'] )
 103                         ? $config['autoResync']
 104                         : false;
 105                 $this->noPushQuickOps = isset( $config['noPushQuickOps'] )
 106                         ? $config['noPushQuickOps']
 107                         : false;
 108                 $this->noPushDirConts = isset( $config['noPushDirConts'] )
 109                         ? $config['noPushDirConts']
 110                         : array();
 111                 // Construct backends here rather than via registration
 112                 // to keep these backends hidden from outside the proxy.
 113                 $namesUsed = array();
 114                 foreach ( $config['backends'] as $index => $config ) {
 115                         if ( isset( $config['template'] ) ) {
 116                                 // Config is just a modified version of a registered backend's.
 117                                 // This should only be used when that config is used only by this backend.
 118                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
 119                         }
 120                         $name = $config['name'];
 121                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 122                                 throw new FileBackendError( "Two or more backends defined with the name $name." );
 123                         }
 124                         $namesUsed[$name] = 1;
 125                         // Alter certain sub-backend settings for sanity
 126                         unset( $config['readOnly'] ); // use proxy backend setting
 127                         unset( $config['fileJournal'] ); // use proxy backend journal
 128                         unset( $config['lockManager'] ); // lock under proxy backend
 129                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
 130                         if ( !empty( $config['isMultiMaster'] ) ) {
 131                                 if ( $this->masterIndex >= 0 ) {
 132                                         throw new FileBackendError( 'More than one master backend defined.' );
 133                                 }
 134                                 $this->masterIndex = $index; // this is the "master"
 135                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 136                         }
 137                         // Create sub-backend object
 138                         if ( !isset( $config['class'] ) ) {
 139                                 throw new FileBackendError( 'No class given for a backend config.' );
 140                         }
 141                         $class = $config['class'];
 142                         $this->backends[$index] = new $class( $config );
 143                 }
 144                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 145                         throw new FileBackendError( 'No master backend defined.' );
 146                 }
 147         }
 148
 149         final protected function doOperationsInternal( array $ops, array $opts ) {
 150                 $status = Status::newGood();
 151
 152                 $mbe = $this->backends[$this->masterIndex]; // convenience
 153
 154                 // Try to lock those files for the scope of this function...
 155                 if ( empty( $opts['nonLocking'] ) ) {
 156                         // Try to lock those files for the scope of this function...
 157                         /** @noinspection PhpUnusedLocalVariableInspection */
 158                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 159                         if ( !$status->isOK() ) {
 160                                 return $status; // abort
 161                         }
 162                 }
 163                 // Clear any cache entries (after locks acquired)
 164                 $this->clearCache();
 165                 $opts['preserveCache'] = true; // only locked files are cached
 166                 // Get the list of paths to read/write...
 167                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 168                 // Check if the paths are valid and accessible on all backends...
 169                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 170                 if ( !$status->isOK() ) {
 171                         return $status; // abort
 172                 }
 173                 // Do a consistency check to see if the backends are consistent...
 174                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 175                 if ( !$syncStatus->isOK() ) {
 176                         wfDebugLog( 'FileOperation', get_class( $this ) .
 177                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 178                         // Try to resync the clone backends to the master on the spot...
 179                         if ( !$this->autoResync || !$this->resyncFiles( $relevantPaths )->isOK() ) {
 180                                 $status->merge( $syncStatus );
 181
 182                                 return $status; // abort
 183                         }
 184                 }
 185                 // Actually attempt the operation batch on the master backend...
 186                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 187                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 188                 $status->merge( $masterStatus );
 189                 // Propagate the operations to the clone backends if there were no unexpected errors
 190                 // and if there were either no expected errors or if the 'force' option was used.
 191                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 192                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 193                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 194                         foreach ( $this->backends as $index => $backend ) {
 195                                 if ( $index !== $this->masterIndex ) { // not done already
 196                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 197                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 198                                 }
 199                         }
 200                 }
 201                 // Make 'success', 'successCount', and 'failCount' fields reflect
 202                 // the overall operation, rather than all the batches for each backend.
 203                 // Do this by only using success values from the master backend's batch.
 204                 $status->success = $masterStatus->success;
 205                 $status->successCount = $masterStatus->successCount;
 206                 $status->failCount = $masterStatus->failCount;
 207
 208                 return $status;
 209         }
 210
 211         /**
 212          * Check that a set of files are consistent across all internal backends
 213          *
 214          * @param array $paths List of storage paths
 215          * @return Status
 216          */
 217         public function consistencyCheck( array $paths ) {
 218                 $status = Status::newGood();
 219                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 220                         return $status; // skip checks
 221                 }
 222
 223                 $mBackend = $this->backends[$this->masterIndex];
 224                 foreach ( $paths as $path ) {
 225                         $params = array( 'src' => $path, 'latest' => true );
 226                         $mParams = $this->substOpPaths( $params, $mBackend );
 227                         // Stat the file on the 'master' backend
 228                         $mStat = $mBackend->getFileStat( $mParams );
 229                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 230                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 231                         } else {
 232                                 $mSha1 = false;
 233                         }
 234                         // Check if all clone backends agree with the master...
 235                         foreach ( $this->backends as $index => $cBackend ) {
 236                                 if ( $index === $this->masterIndex ) {
 237                                         continue; // master
 238                                 }
 239                                 $cParams = $this->substOpPaths( $params, $cBackend );
 240                                 $cStat = $cBackend->getFileStat( $cParams );
 241                                 if ( $mStat ) { // file is in master
 242                                         if ( !$cStat ) { // file should exist
 243                                                 $status->fatal( 'backend-fail-synced', $path );
 244                                                 continue;
 245                                         }
 246                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 247                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 248                                                         $status->fatal( 'backend-fail-synced', $path );
 249                                                         continue;
 250                                                 }
 251                                         }
 252                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 253                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 254                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 255                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 256                                                         $status->fatal( 'backend-fail-synced', $path );
 257                                                         continue;
 258                                                 }
 259                                         }
 260                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 261                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 262                                                         $status->fatal( 'backend-fail-synced', $path );
 263                                                         continue;
 264                                                 }
 265                                         }
 266                                 } else { // file is not in master
 267                                         if ( $cStat ) { // file should not exist
 268                                                 $status->fatal( 'backend-fail-synced', $path );
 269                                         }
 270                                 }
 271                         }
 272                 }
 273
 274                 return $status;
 275         }
 276
 277         /**
 278          * Check that a set of file paths are usable across all internal backends
 279          *
 280          * @param array $paths List of storage paths
 281          * @return Status
 282          */
 283         public function accessibilityCheck( array $paths ) {
 284                 $status = Status::newGood();
 285                 if ( count( $this->backends ) <= 1 ) {
 286                         return $status; // skip checks
 287                 }
 288
 289                 foreach ( $paths as $path ) {
 290                         foreach ( $this->backends as $backend ) {
 291                                 $realPath = $this->substPaths( $path, $backend );
 292                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 293                                         $status->fatal( 'backend-fail-usable', $path );
 294                                 }
 295                         }
 296                 }
 297
 298                 return $status;
 299         }
 300
 301         /**
 302          * Check that a set of files are consistent across all internal backends
 303          * and re-synchronize those files against the "multi master" if needed.
 304          *
 305          * @param array $paths List of storage paths
 306          * @return Status
 307          */
 308         public function resyncFiles( array $paths ) {
 309                 $status = Status::newGood();
 310
 311                 $mBackend = $this->backends[$this->masterIndex];
 312                 foreach ( $paths as $path ) {
 313                         $mPath = $this->substPaths( $path, $mBackend );
 314                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 315                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 316                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 317                                 $status->fatal( 'backend-fail-internal', $this->name );
 318                                 wfDebugLog( 'FileOperation', __METHOD__
 319                                         . ': File is not available on the master backend' );
 320                                 continue; // file is not available on the master backend...
 321                         }
 322                         // Check of all clone backends agree with the master...
 323                         foreach ( $this->backends as $index => $cBackend ) {
 324                                 if ( $index === $this->masterIndex ) {
 325                                         continue; // master
 326                                 }
 327                                 $cPath = $this->substPaths( $path, $cBackend );
 328                                 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath, 'latest' => true ) );
 329                                 $cStat = $cBackend->getFileStat( array( 'src' => $cPath, 'latest' => true ) );
 330                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 331                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 332                                         wfDebugLog( 'FileOperation', __METHOD__ .
 333                                                 ': File is not available on the clone backend' );
 334                                         continue; // file is not available on the clone backend...
 335                                 }
 336                                 if ( $mSha1 === $cSha1 ) {
 337                                         // already synced; nothing to do
 338                                 } elseif ( $mSha1 !== false ) { // file is in master
 339                                         if ( $this->autoResync === 'conservative'
 340                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 341                                         ) {
 342                                                 $status->fatal( 'backend-fail-synced', $path );
 343                                                 continue; // don't rollback data
 344                                         }
 345                                         $fsFile = $mBackend->getLocalReference(
 346                                                 array( 'src' => $mPath, 'latest' => true ) );
 347                                         $status->merge( $cBackend->quickStore(
 348                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 349                                         ) );
 350                                 } elseif ( $mStat === false ) { // file is not in master
 351                                         if ( $this->autoResync === 'conservative' ) {
 352                                                 $status->fatal( 'backend-fail-synced', $path );
 353                                                 continue; // don't delete data
 354                                         }
 355                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 356                                 }
 357                         }
 358                 }
 359
 360                 return $status;
 361         }
 362
 363         /**
 364          * Get a list of file storage paths to read or write for a list of operations
 365          *
 366          * @param array $ops Same format as doOperations()
 367          * @return array List of storage paths to files (does not include directories)
 368          */
 369         protected function fileStoragePathsForOps( array $ops ) {
 370                 $paths = array();
 371                 foreach ( $ops as $op ) {
 372                         if ( isset( $op['src'] ) ) {
 373                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 374                                 // is no source file, nothing should happen and there should be no errors.
 375                                 if ( empty( $op['ignoreMissingSource'] )
 376                                         || $this->fileExists( array( 'src' => $op['src'] ) )
 377                                 ) {
 378                                         $paths[] = $op['src'];
 379                                 }
 380                         }
 381                         if ( isset( $op['srcs'] ) ) {
 382                                 $paths = array_merge( $paths, $op['srcs'] );
 383                         }
 384                         if ( isset( $op['dst'] ) ) {
 385                                 $paths[] = $op['dst'];
 386                         }
 387                 }
 388
 389                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 390         }
 391
 392         /**
 393          * Substitute the backend name in storage path parameters
 394          * for a set of operations with that of a given internal backend.
 395          *
 396          * @param array $ops List of file operation arrays
 397          * @param FileBackendStore $backend
 398          * @return array
 399          */
 400         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 401                 $newOps = array(); // operations
 402                 foreach ( $ops as $op ) {
 403                         $newOp = $op; // operation
 404                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 405                                 if ( isset( $newOp[$par] ) ) { // string or array
 406                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 407                                 }
 408                         }
 409                         $newOps[] = $newOp;
 410                 }
 411
 412                 return $newOps;
 413         }
 414
 415         /**
 416          * Same as substOpBatchPaths() but for a single operation
 417          *
 418          * @param array $ops File operation array
 419          * @param FileBackendStore $backend
 420          * @return array
 421          */
 422         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 423                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 424
 425                 return $newOps[0];
 426         }
 427
 428         /**
 429          * Substitute the backend of storage paths with an internal backend's name
 430          *
 431          * @param array|string $paths List of paths or single string path
 432          * @param FileBackendStore $backend
 433          * @return array|string
 434          */
 435         protected function substPaths( $paths, FileBackendStore $backend ) {
 436                 return preg_replace(
 437                         '!^mwstore://' . preg_quote( $this->name, '!' ) . '/!',
 438                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 439                         $paths // string or array
 440                 );
 441         }
 442
 443         /**
 444          * Substitute the backend of internal storage paths with the proxy backend's name
 445          *
 446          * @param array|string $paths List of paths or single string path
 447          * @return array|string
 448          */
 449         protected function unsubstPaths( $paths ) {
 450                 return preg_replace(
 451                         '!^mwstore://([^/]+)!',
 452                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 453                         $paths // string or array
 454                 );
 455         }
 456
 457         protected function doQuickOperationsInternal( array $ops ) {
 458                 $status = Status::newGood();
 459                 // Do the operations on the master backend; setting Status fields...
 460                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 461                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 462                 $status->merge( $masterStatus );
 463                 // Propagate the operations to the clone backends...
 464                 if ( !$this->noPushQuickOps ) {
 465                         foreach ( $this->backends as $index => $backend ) {
 466                                 if ( $index !== $this->masterIndex ) { // not done already
 467                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 468                                         $status->merge( $backend->doQuickOperations( $realOps ) );
 469                                 }
 470                         }
 471                 }
 472                 // Make 'success', 'successCount', and 'failCount' fields reflect
 473                 // the overall operation, rather than all the batches for each backend.
 474                 // Do this by only using success values from the master backend's batch.
 475                 $status->success = $masterStatus->success;
 476                 $status->successCount = $masterStatus->successCount;
 477                 $status->failCount = $masterStatus->failCount;
 478
 479                 return $status;
 480         }
 481
 482         /**
 483          * @param string $path Storage path
 484          * @return bool Path container should have dir changes pushed to all backends
 485          */
 486         protected function replicateContainerDirChanges( $path ) {
 487                 list( , $shortCont, ) = self::splitStoragePath( $path );
 488
 489                 return !in_array( $shortCont, $this->noPushDirConts );
 490         }
 491
 492         protected function doPrepare( array $params ) {
 493                 $status = Status::newGood();
 494                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 495                 foreach ( $this->backends as $index => $backend ) {
 496                         if ( $replicate || $index == $this->masterIndex ) {
 497                                 $realParams = $this->substOpPaths( $params, $backend );
 498                                 $status->merge( $backend->doPrepare( $realParams ) );
 499                         }
 500                 }
 501
 502                 return $status;
 503         }
 504
 505         protected function doSecure( array $params ) {
 506                 $status = Status::newGood();
 507                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 508                 foreach ( $this->backends as $index => $backend ) {
 509                         if ( $replicate || $index == $this->masterIndex ) {
 510                                 $realParams = $this->substOpPaths( $params, $backend );
 511                                 $status->merge( $backend->doSecure( $realParams ) );
 512                         }
 513                 }
 514
 515                 return $status;
 516         }
 517
 518         protected function doPublish( array $params ) {
 519                 $status = Status::newGood();
 520                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 521                 foreach ( $this->backends as $index => $backend ) {
 522                         if ( $replicate || $index == $this->masterIndex ) {
 523                                 $realParams = $this->substOpPaths( $params, $backend );
 524                                 $status->merge( $backend->doPublish( $realParams ) );
 525                         }
 526                 }
 527
 528                 return $status;
 529         }
 530
 531         protected function doClean( array $params ) {
 532                 $status = Status::newGood();
 533                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 534                 foreach ( $this->backends as $index => $backend ) {
 535                         if ( $replicate || $index == $this->masterIndex ) {
 536                                 $realParams = $this->substOpPaths( $params, $backend );
 537                                 $status->merge( $backend->doClean( $realParams ) );
 538                         }
 539                 }
 540
 541                 return $status;
 542         }
 543
 544         public function concatenate( array $params ) {
 545                 // We are writing to an FS file, so we don't need to do this per-backend
 546                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 547
 548                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 549         }
 550
 551         public function fileExists( array $params ) {
 552                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 553
 554                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 555         }
 556
 557         public function getFileTimestamp( array $params ) {
 558                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 559
 560                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 561         }
 562
 563         public function getFileSize( array $params ) {
 564                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 565
 566                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 567         }
 568
 569         public function getFileStat( array $params ) {
 570                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 571
 572                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 573         }
 574
 575         public function getFileXAttributes( array $params ) {
 576                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 577
 578                 return $this->backends[$this->masterIndex]->getFileXAttributes( $realParams );
 579         }
 580
 581         public function getFileContentsMulti( array $params ) {
 582                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 583                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 584
 585                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 586                 foreach ( $contentsM as $path => $data ) {
 587                         $contents[$this->unsubstPaths( $path )] = $data;
 588                 }
 589
 590                 return $contents;
 591         }
 592
 593         public function getFileSha1Base36( array $params ) {
 594                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 595
 596                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 597         }
 598
 599         public function getFileProps( array $params ) {
 600                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 601
 602                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 603         }
 604
 605         public function streamFile( array $params ) {
 606                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 607
 608                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 609         }
 610
 611         public function getLocalReferenceMulti( array $params ) {
 612                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 613                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 614
 615                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 616                 foreach ( $fsFilesM as $path => $fsFile ) {
 617                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 618                 }
 619
 620                 return $fsFiles;
 621         }
 622
 623         public function getLocalCopyMulti( array $params ) {
 624                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 625                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 626
 627                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 628                 foreach ( $tempFilesM as $path => $tempFile ) {
 629                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 630                 }
 631
 632                 return $tempFiles;
 633         }
 634
 635         public function getFileHttpUrl( array $params ) {
 636                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 637
 638                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 639         }
 640
 641         public function directoryExists( array $params ) {
 642                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 643
 644                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 645         }
 646
 647         public function getDirectoryList( array $params ) {
 648                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 649
 650                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 651         }
 652
 653         public function getFileList( array $params ) {
 654                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 655
 656                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 657         }
 658
 659         public function getFeatures() {
 660                 return $this->backends[$this->masterIndex]->getFeatures();
 661         }
 662
 663         public function clearCache( array $paths = null ) {
 664                 foreach ( $this->backends as $backend ) {
 665                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 666                         $backend->clearCache( $realPaths );
 667                 }
 668         }
 669
 670         public function preloadCache( array $paths ) {
 671                 $realPaths = $this->substPaths( $paths, $this->backends[$this->masterIndex] );
 672                 $this->backends[$this->masterIndex]->preloadCache( $realPaths );
 673         }
 674
 675         public function preloadFileStat( array $params ) {
 676                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 677                 return $this->backends[$this->masterIndex]->preloadFileStat( $realParams );
 678         }
 679
 680         public function getScopedLocksForOps( array $ops, Status $status ) {
 681                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 682                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 683                 // Get the paths to lock from the master backend
 684                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 685                 // Get the paths under the proxy backend's name
 686                 $pbPaths = array(
 687                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 688                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 689                 );
 690
 691                 // Actually acquire the locks
 692                 return $this->getScopedFileLocks( $pbPaths, 'mixed', $status );
 693         }
 694 }