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