includes/libs/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  */
  23
  24 /**
  25  * @brief Proxy backend that mirrors writes to several internal backends.
  26  *
  27  * This class defines a multi-write backend. Multiple backends can be
  28  * registered to this proxy backend and it will act as a single backend.
  29  * Use this when all access to those backends is through this proxy backend.
  30  * At least one of the backends must be declared the "master" backend.
  31  *
  32  * Only use this class when transitioning from one storage system to another.
  33  *
  34  * Read operations are only done on the 'master' backend for consistency.
  35  * Write operations are performed on all backends, starting with the master.
  36  * This makes a best-effort to have transactional semantics, but since requests
  37  * may sometimes fail, the use of "autoResync" or background scripts to fix
  38  * inconsistencies is important.
  39  *
  40  * @ingroup FileBackend
  41  * @since 1.19
  42  */
  43 class FileBackendMultiWrite extends FileBackend {
  44         /** @var FileBackendStore[] Prioritized list of FileBackendStore objects */
  45         protected $backends = [];
  46
  47         /** @var int Index of master backend */
  48         protected $masterIndex = -1;
  49         /** @var int Index of read affinity backend */
  50         protected $readIndex = -1;
  51
  52         /** @var int Bitfield */
  53         protected $syncChecks = 0;
  54         /** @var string|bool */
  55         protected $autoResync = false;
  56
  57         /** @var bool */
  58         protected $asyncWrites = false;
  59
  60         /* Possible internal backend consistency checks */
  61         const CHECK_SIZE = 1;
  62         const CHECK_TIME = 2;
  63         const CHECK_SHA1 = 4;
  64
  65         /**
  66          * Construct a proxy backend that consists of several internal backends.
  67          * Locking, journaling, and read-only checks are handled by the proxy backend.
  68          *
  69          * Additional $config params include:
  70          *   - backends       : Array of backend config and multi-backend settings.
  71          *                      Each value is the config used in the constructor of a
  72          *                      FileBackendStore class, but with these additional settings:
  73          *                        - class         : The name of the backend class
  74          *                        - isMultiMaster : This must be set for one backend.
  75          *                        - readAffinity  : Use this for reads without 'latest' set.
  76          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  77          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  78          *                      There are constants for SIZE, TIME, and SHA1.
  79          *                      The checks are done before allowing any file operations.
  80          *   - autoResync     : Automatically resync the clone backends to the master backend
  81          *                      when pre-operation sync checks fail. This should only be used
  82          *                      if the master backend is stable and not missing any files.
  83          *                      Use "conservative" to limit resyncing to copying newer master
  84          *                      backend files over older (or non-existing) clone backend files.
  85          *                      Cases that cannot be handled will result in operation abortion.
  86          *   - replication    : Set to 'async' to defer file operations on the non-master backends.
  87          *                      This will apply such updates post-send for web requests. Note that
  88          *                      any checks from "syncChecks" are still synchronous.
  89          *
  90          * @param array $config
  91          * @throws FileBackendError
  92          */
  93         public function __construct( array $config ) {
  94                 parent::__construct( $config );
  95                 $this->syncChecks = isset( $config['syncChecks'] )
  96                         ? $config['syncChecks']
  97                         : self::CHECK_SIZE;
  98                 $this->autoResync = isset( $config['autoResync'] )
  99                         ? $config['autoResync']
 100                         : false;
 101                 $this->asyncWrites = isset( $config['replication'] ) && $config['replication'] === 'async';
 102                 // Construct backends here rather than via registration
 103                 // to keep these backends hidden from outside the proxy.
 104                 $namesUsed = [];
 105                 foreach ( $config['backends'] as $index => $config ) {
 106                         $name = $config['name'];
 107                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 108                                 throw new LogicException( "Two or more backends defined with the name $name." );
 109                         }
 110                         $namesUsed[$name] = 1;
 111                         // Alter certain sub-backend settings for sanity
 112                         unset( $config['readOnly'] ); // use proxy backend setting
 113                         unset( $config['fileJournal'] ); // use proxy backend journal
 114                         unset( $config['lockManager'] ); // lock under proxy backend
 115                         $config['domainId'] = $this->domainId; // use the proxy backend wiki ID
 116                         if ( !empty( $config['isMultiMaster'] ) ) {
 117                                 if ( $this->masterIndex >= 0 ) {
 118                                         throw new LogicException( 'More than one master backend defined.' );
 119                                 }
 120                                 $this->masterIndex = $index; // this is the "master"
 121                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 122                         }
 123                         if ( !empty( $config['readAffinity'] ) ) {
 124                                 $this->readIndex = $index; // prefer this for reads
 125                         }
 126                         // Create sub-backend object
 127                         if ( !isset( $config['class'] ) ) {
 128                                 throw new InvalidArgumentException( 'No class given for a backend config.' );
 129                         }
 130                         $class = $config['class'];
 131                         $this->backends[$index] = new $class( $config );
 132                 }
 133                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 134                         throw new LogicException( 'No master backend defined.' );
 135                 }
 136                 if ( $this->readIndex < 0 ) {
 137                         $this->readIndex = $this->masterIndex; // default
 138                 }
 139         }
 140
 141         final protected function doOperationsInternal( array $ops, array $opts ) {
 142                 $status = $this->newStatus();
 143
 144                 $mbe = $this->backends[$this->masterIndex]; // convenience
 145
 146                 // Try to lock those files for the scope of this function...
 147                 $scopeLock = null;
 148                 if ( empty( $opts['nonLocking'] ) ) {
 149                         // Try to lock those files for the scope of this function...
 150                         /** @noinspection PhpUnusedLocalVariableInspection */
 151                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 152                         if ( !$status->isOK() ) {
 153                                 return $status; // abort
 154                         }
 155                 }
 156                 // Clear any cache entries (after locks acquired)
 157                 $this->clearCache();
 158                 $opts['preserveCache'] = true; // only locked files are cached
 159                 // Get the list of paths to read/write...
 160                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 161                 // Check if the paths are valid and accessible on all backends...
 162                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 163                 if ( !$status->isOK() ) {
 164                         return $status; // abort
 165                 }
 166                 // Do a consistency check to see if the backends are consistent...
 167                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 168                 if ( !$syncStatus->isOK() ) {
 169                         wfDebugLog( 'FileOperation', static::class .
 170                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 171                         // Try to resync the clone backends to the master on the spot...
 172                         if ( $this->autoResync === false
 173                                 || !$this->resyncFiles( $relevantPaths, $this->autoResync )->isOK()
 174                         ) {
 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 ) {
 191                                         continue; // done already
 192                                 }
 193
 194                                 $realOps = $this->substOpBatchPaths( $ops, $backend );
 195                                 if ( $this->asyncWrites && !$this->hasVolatileSources( $ops ) ) {
 196                                         // Bind $scopeLock to the callback to preserve locks
 197                                         DeferredUpdates::addCallableUpdate(
 198                                                 function () use ( $backend, $realOps, $opts, $scopeLock, $relevantPaths ) {
 199                                                         wfDebugLog( 'FileOperationReplication',
 200                                                                 "'{$backend->getName()}' async replication; paths: " .
 201                                                                 FormatJson::encode( $relevantPaths ) );
 202                                                         $backend->doOperations( $realOps, $opts );
 203                                                 }
 204                                         );
 205                                 } else {
 206                                         wfDebugLog( 'FileOperationReplication',
 207                                                 "'{$backend->getName()}' sync replication; paths: " .
 208                                                 FormatJson::encode( $relevantPaths ) );
 209                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 210                                 }
 211                         }
 212                 }
 213                 // Make 'success', 'successCount', and 'failCount' fields reflect
 214                 // the overall operation, rather than all the batches for each backend.
 215                 // Do this by only using success values from the master backend's batch.
 216                 $status->success = $masterStatus->success;
 217                 $status->successCount = $masterStatus->successCount;
 218                 $status->failCount = $masterStatus->failCount;
 219
 220                 return $status;
 221         }
 222
 223         /**
 224          * Check that a set of files are consistent across all internal backends
 225          *
 226          * @param array $paths List of storage paths
 227          * @return StatusValue
 228          */
 229         public function consistencyCheck( array $paths ) {
 230                 $status = $this->newStatus();
 231                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 232                         return $status; // skip checks
 233                 }
 234
 235                 // Preload all of the stat info in as few round trips as possible...
 236                 foreach ( $this->backends as $backend ) {
 237                         $realPaths = $this->substPaths( $paths, $backend );
 238                         $backend->preloadFileStat( [ 'srcs' => $realPaths, 'latest' => true ] );
 239                 }
 240
 241                 $mBackend = $this->backends[$this->masterIndex];
 242                 foreach ( $paths as $path ) {
 243                         $params = [ 'src' => $path, 'latest' => true ];
 244                         $mParams = $this->substOpPaths( $params, $mBackend );
 245                         // Stat the file on the 'master' backend
 246                         $mStat = $mBackend->getFileStat( $mParams );
 247                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 248                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 249                         } else {
 250                                 $mSha1 = false;
 251                         }
 252                         // Check if all clone backends agree with the master...
 253                         foreach ( $this->backends as $index => $cBackend ) {
 254                                 if ( $index === $this->masterIndex ) {
 255                                         continue; // master
 256                                 }
 257                                 $cParams = $this->substOpPaths( $params, $cBackend );
 258                                 $cStat = $cBackend->getFileStat( $cParams );
 259                                 if ( $mStat ) { // file is in master
 260                                         if ( !$cStat ) { // file should exist
 261                                                 $status->fatal( 'backend-fail-synced', $path );
 262                                                 continue;
 263                                         }
 264                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 265                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 266                                                         $status->fatal( 'backend-fail-synced', $path );
 267                                                         continue;
 268                                                 }
 269                                         }
 270                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 271                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 272                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 273                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 274                                                         $status->fatal( 'backend-fail-synced', $path );
 275                                                         continue;
 276                                                 }
 277                                         }
 278                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 279                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 280                                                         $status->fatal( 'backend-fail-synced', $path );
 281                                                         continue;
 282                                                 }
 283                                         }
 284                                 } else { // file is not in master
 285                                         if ( $cStat ) { // file should not exist
 286                                                 $status->fatal( 'backend-fail-synced', $path );
 287                                         }
 288                                 }
 289                         }
 290                 }
 291
 292                 return $status;
 293         }
 294
 295         /**
 296          * Check that a set of file paths are usable across all internal backends
 297          *
 298          * @param array $paths List of storage paths
 299          * @return StatusValue
 300          */
 301         public function accessibilityCheck( array $paths ) {
 302                 $status = $this->newStatus();
 303                 if ( count( $this->backends ) <= 1 ) {
 304                         return $status; // skip checks
 305                 }
 306
 307                 foreach ( $paths as $path ) {
 308                         foreach ( $this->backends as $backend ) {
 309                                 $realPath = $this->substPaths( $path, $backend );
 310                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 311                                         $status->fatal( 'backend-fail-usable', $path );
 312                                 }
 313                         }
 314                 }
 315
 316                 return $status;
 317         }
 318
 319         /**
 320          * Check that a set of files are consistent across all internal backends
 321          * and re-synchronize those files against the "multi master" if needed.
 322          *
 323          * @param array $paths List of storage paths
 324          * @param string|bool $resyncMode False, True, or "conservative"; see __construct()
 325          * @return StatusValue
 326          */
 327         public function resyncFiles( array $paths, $resyncMode = true ) {
 328                 $status = $this->newStatus();
 329
 330                 $mBackend = $this->backends[$this->masterIndex];
 331                 foreach ( $paths as $path ) {
 332                         $mPath = $this->substPaths( $path, $mBackend );
 333                         $mSha1 = $mBackend->getFileSha1Base36( [ 'src' => $mPath, 'latest' => true ] );
 334                         $mStat = $mBackend->getFileStat( [ 'src' => $mPath, 'latest' => true ] );
 335                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 336                                 $status->fatal( 'backend-fail-internal', $this->name );
 337                                 wfDebugLog( 'FileOperation', __METHOD__
 338                                         . ': File is not available on the master backend' );
 339                                 continue; // file is not available on the master backend...
 340                         }
 341                         // Check of all clone backends agree with the master...
 342                         foreach ( $this->backends as $index => $cBackend ) {
 343                                 if ( $index === $this->masterIndex ) {
 344                                         continue; // master
 345                                 }
 346                                 $cPath = $this->substPaths( $path, $cBackend );
 347                                 $cSha1 = $cBackend->getFileSha1Base36( [ 'src' => $cPath, 'latest' => true ] );
 348                                 $cStat = $cBackend->getFileStat( [ 'src' => $cPath, 'latest' => true ] );
 349                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 350                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 351                                         wfDebugLog( 'FileOperation', __METHOD__ .
 352                                                 ': File is not available on the clone backend' );
 353                                         continue; // file is not available on the clone backend...
 354                                 }
 355                                 if ( $mSha1 === $cSha1 ) {
 356                                         // already synced; nothing to do
 357                                 } elseif ( $mSha1 !== false ) { // file is in master
 358                                         if ( $resyncMode === 'conservative'
 359                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 360                                         ) {
 361                                                 $status->fatal( 'backend-fail-synced', $path );
 362                                                 continue; // don't rollback data
 363                                         }
 364                                         $fsFile = $mBackend->getLocalReference(
 365                                                 [ 'src' => $mPath, 'latest' => true ] );
 366                                         $status->merge( $cBackend->quickStore(
 367                                                 [ 'src' => $fsFile->getPath(), 'dst' => $cPath ]
 368                                         ) );
 369                                 } elseif ( $mStat === false ) { // file is not in master
 370                                         if ( $resyncMode === 'conservative' ) {
 371                                                 $status->fatal( 'backend-fail-synced', $path );
 372                                                 continue; // don't delete data
 373                                         }
 374                                         $status->merge( $cBackend->quickDelete( [ 'src' => $cPath ] ) );
 375                                 }
 376                         }
 377                 }
 378
 379                 if ( !$status->isOK() ) {
 380                         wfDebugLog( 'FileOperation', static::class .
 381                                 " failed to resync: " . FormatJson::encode( $paths ) );
 382                 }
 383
 384                 return $status;
 385         }
 386
 387         /**
 388          * Get a list of file storage paths to read or write for a list of operations
 389          *
 390          * @param array $ops Same format as doOperations()
 391          * @return array List of storage paths to files (does not include directories)
 392          */
 393         protected function fileStoragePathsForOps( array $ops ) {
 394                 $paths = [];
 395                 foreach ( $ops as $op ) {
 396                         if ( isset( $op['src'] ) ) {
 397                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 398                                 // is no source file, nothing should happen and there should be no errors.
 399                                 if ( empty( $op['ignoreMissingSource'] )
 400                                         || $this->fileExists( [ 'src' => $op['src'] ] )
 401                                 ) {
 402                                         $paths[] = $op['src'];
 403                                 }
 404                         }
 405                         if ( isset( $op['srcs'] ) ) {
 406                                 $paths = array_merge( $paths, $op['srcs'] );
 407                         }
 408                         if ( isset( $op['dst'] ) ) {
 409                                 $paths[] = $op['dst'];
 410                         }
 411                 }
 412
 413                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 414         }
 415
 416         /**
 417          * Substitute the backend name in storage path parameters
 418          * for a set of operations with that of a given internal backend.
 419          *
 420          * @param array $ops List of file operation arrays
 421          * @param FileBackendStore $backend
 422          * @return array
 423          */
 424         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 425                 $newOps = []; // operations
 426                 foreach ( $ops as $op ) {
 427                         $newOp = $op; // operation
 428                         foreach ( [ 'src', 'srcs', 'dst', 'dir' ] as $par ) {
 429                                 if ( isset( $newOp[$par] ) ) { // string or array
 430                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 431                                 }
 432                         }
 433                         $newOps[] = $newOp;
 434                 }
 435
 436                 return $newOps;
 437         }
 438
 439         /**
 440          * Same as substOpBatchPaths() but for a single operation
 441          *
 442          * @param array $ops File operation array
 443          * @param FileBackendStore $backend
 444          * @return array
 445          */
 446         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 447                 $newOps = $this->substOpBatchPaths( [ $ops ], $backend );
 448
 449                 return $newOps[0];
 450         }
 451
 452         /**
 453          * Substitute the backend of storage paths with an internal backend's name
 454          *
 455          * @param array|string $paths List of paths or single string path
 456          * @param FileBackendStore $backend
 457          * @return array|string
 458          */
 459         protected function substPaths( $paths, FileBackendStore $backend ) {
 460                 return preg_replace(
 461                         '!^mwstore://' . preg_quote( $this->name, '!' ) . '/!',
 462                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 463                         $paths // string or array
 464                 );
 465         }
 466
 467         /**
 468          * Substitute the backend of internal storage paths with the proxy backend's name
 469          *
 470          * @param array|string $paths List of paths or single string path
 471          * @return array|string
 472          */
 473         protected function unsubstPaths( $paths ) {
 474                 return preg_replace(
 475                         '!^mwstore://([^/]+)!',
 476                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 477                         $paths // string or array
 478                 );
 479         }
 480
 481         /**
 482          * @param array $ops File operations for FileBackend::doOperations()
 483          * @return bool Whether there are file path sources with outside lifetime/ownership
 484          */
 485         protected function hasVolatileSources( array $ops ) {
 486                 foreach ( $ops as $op ) {
 487                         if ( $op['op'] === 'store' && !isset( $op['srcRef'] ) ) {
 488                                 return true; // source file might be deleted anytime after do*Operations()
 489                         }
 490                 }
 491
 492                 return false;
 493         }
 494
 495         protected function doQuickOperationsInternal( array $ops ) {
 496                 $status = $this->newStatus();
 497                 // Do the operations on the master backend; setting StatusValue fields...
 498                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 499                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 500                 $status->merge( $masterStatus );
 501                 // Propagate the operations to the clone backends...
 502                 foreach ( $this->backends as $index => $backend ) {
 503                         if ( $index === $this->masterIndex ) {
 504                                 continue; // done already
 505                         }
 506
 507                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 508                         if ( $this->asyncWrites && !$this->hasVolatileSources( $ops ) ) {
 509                                 DeferredUpdates::addCallableUpdate(
 510                                         function () use ( $backend, $realOps ) {
 511                                                 $backend->doQuickOperations( $realOps );
 512                                         }
 513                                 );
 514                         } else {
 515                                 $status->merge( $backend->doQuickOperations( $realOps ) );
 516                         }
 517                 }
 518                 // Make 'success', 'successCount', and 'failCount' fields reflect
 519                 // the overall operation, rather than all the batches for each backend.
 520                 // Do this by only using success values from the master backend's batch.
 521                 $status->success = $masterStatus->success;
 522                 $status->successCount = $masterStatus->successCount;
 523                 $status->failCount = $masterStatus->failCount;
 524
 525                 return $status;
 526         }
 527
 528         protected function doPrepare( array $params ) {
 529                 return $this->doDirectoryOp( 'prepare', $params );
 530         }
 531
 532         protected function doSecure( array $params ) {
 533                 return $this->doDirectoryOp( 'secure', $params );
 534         }
 535
 536         protected function doPublish( array $params ) {
 537                 return $this->doDirectoryOp( 'publish', $params );
 538         }
 539
 540         protected function doClean( array $params ) {
 541                 return $this->doDirectoryOp( 'clean', $params );
 542         }
 543
 544         /**
 545          * @param string $method One of (doPrepare,doSecure,doPublish,doClean)
 546          * @param array $params Method arguments
 547          * @return StatusValue
 548          */
 549         protected function doDirectoryOp( $method, array $params ) {
 550                 $status = $this->newStatus();
 551
 552                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 553                 $masterStatus = $this->backends[$this->masterIndex]->$method( $realParams );
 554                 $status->merge( $masterStatus );
 555
 556                 foreach ( $this->backends as $index => $backend ) {
 557                         if ( $index === $this->masterIndex ) {
 558                                 continue; // already done
 559                         }
 560
 561                         $realParams = $this->substOpPaths( $params, $backend );
 562                         if ( $this->asyncWrites ) {
 563                                 DeferredUpdates::addCallableUpdate(
 564                                         function () use ( $backend, $method, $realParams ) {
 565                                                 $backend->$method( $realParams );
 566                                         }
 567                                 );
 568                         } else {
 569                                 $status->merge( $backend->$method( $realParams ) );
 570                         }
 571                 }
 572
 573                 return $status;
 574         }
 575
 576         public function concatenate( array $params ) {
 577                 $status = $this->newStatus();
 578                 // We are writing to an FS file, so we don't need to do this per-backend
 579                 $index = $this->getReadIndexFromParams( $params );
 580                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 581
 582                 $status->merge( $this->backends[$index]->concatenate( $realParams ) );
 583
 584                 return $status;
 585         }
 586
 587         public function fileExists( array $params ) {
 588                 $index = $this->getReadIndexFromParams( $params );
 589                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 590
 591                 return $this->backends[$index]->fileExists( $realParams );
 592         }
 593
 594         public function getFileTimestamp( array $params ) {
 595                 $index = $this->getReadIndexFromParams( $params );
 596                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 597
 598                 return $this->backends[$index]->getFileTimestamp( $realParams );
 599         }
 600
 601         public function getFileSize( array $params ) {
 602                 $index = $this->getReadIndexFromParams( $params );
 603                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 604
 605                 return $this->backends[$index]->getFileSize( $realParams );
 606         }
 607
 608         public function getFileStat( array $params ) {
 609                 $index = $this->getReadIndexFromParams( $params );
 610                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 611
 612                 return $this->backends[$index]->getFileStat( $realParams );
 613         }
 614
 615         public function getFileXAttributes( array $params ) {
 616                 $index = $this->getReadIndexFromParams( $params );
 617                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 618
 619                 return $this->backends[$index]->getFileXAttributes( $realParams );
 620         }
 621
 622         public function getFileContentsMulti( array $params ) {
 623                 $index = $this->getReadIndexFromParams( $params );
 624                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 625
 626                 $contentsM = $this->backends[$index]->getFileContentsMulti( $realParams );
 627
 628                 $contents = []; // (path => FSFile) mapping using the proxy backend's name
 629                 foreach ( $contentsM as $path => $data ) {
 630                         $contents[$this->unsubstPaths( $path )] = $data;
 631                 }
 632
 633                 return $contents;
 634         }
 635
 636         public function getFileSha1Base36( array $params ) {
 637                 $index = $this->getReadIndexFromParams( $params );
 638                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 639
 640                 return $this->backends[$index]->getFileSha1Base36( $realParams );
 641         }
 642
 643         public function getFileProps( array $params ) {
 644                 $index = $this->getReadIndexFromParams( $params );
 645                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 646
 647                 return $this->backends[$index]->getFileProps( $realParams );
 648         }
 649
 650         public function streamFile( array $params ) {
 651                 $index = $this->getReadIndexFromParams( $params );
 652                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 653
 654                 return $this->backends[$index]->streamFile( $realParams );
 655         }
 656
 657         public function getLocalReferenceMulti( array $params ) {
 658                 $index = $this->getReadIndexFromParams( $params );
 659                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 660
 661                 $fsFilesM = $this->backends[$index]->getLocalReferenceMulti( $realParams );
 662
 663                 $fsFiles = []; // (path => FSFile) mapping using the proxy backend's name
 664                 foreach ( $fsFilesM as $path => $fsFile ) {
 665                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 666                 }
 667
 668                 return $fsFiles;
 669         }
 670
 671         public function getLocalCopyMulti( array $params ) {
 672                 $index = $this->getReadIndexFromParams( $params );
 673                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 674
 675                 $tempFilesM = $this->backends[$index]->getLocalCopyMulti( $realParams );
 676
 677                 $tempFiles = []; // (path => TempFSFile) mapping using the proxy backend's name
 678                 foreach ( $tempFilesM as $path => $tempFile ) {
 679                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 680                 }
 681
 682                 return $tempFiles;
 683         }
 684
 685         public function getFileHttpUrl( array $params ) {
 686                 $index = $this->getReadIndexFromParams( $params );
 687                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 688
 689                 return $this->backends[$index]->getFileHttpUrl( $realParams );
 690         }
 691
 692         public function directoryExists( array $params ) {
 693                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 694
 695                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 696         }
 697
 698         public function getDirectoryList( array $params ) {
 699                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 700
 701                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 702         }
 703
 704         public function getFileList( array $params ) {
 705                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 706
 707                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 708         }
 709
 710         public function getFeatures() {
 711                 return $this->backends[$this->masterIndex]->getFeatures();
 712         }
 713
 714         public function clearCache( array $paths = null ) {
 715                 foreach ( $this->backends as $backend ) {
 716                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 717                         $backend->clearCache( $realPaths );
 718                 }
 719         }
 720
 721         public function preloadCache( array $paths ) {
 722                 $realPaths = $this->substPaths( $paths, $this->backends[$this->readIndex] );
 723                 $this->backends[$this->readIndex]->preloadCache( $realPaths );
 724         }
 725
 726         public function preloadFileStat( array $params ) {
 727                 $index = $this->getReadIndexFromParams( $params );
 728                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 729
 730                 return $this->backends[$index]->preloadFileStat( $realParams );
 731         }
 732
 733         public function getScopedLocksForOps( array $ops, StatusValue $status ) {
 734                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 735                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 736                 // Get the paths to lock from the master backend
 737                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 738                 // Get the paths under the proxy backend's name
 739                 $pbPaths = [
 740                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 741                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 742                 ];
 743
 744                 // Actually acquire the locks
 745                 return $this->getScopedFileLocks( $pbPaths, 'mixed', $status );
 746         }
 747
 748         /**
 749          * @param array $params
 750          * @return int The master or read affinity backend index, based on $params['latest']
 751          */
 752         protected function getReadIndexFromParams( array $params ) {
 753                 return !empty( $params['latest'] ) ? $this->masterIndex : $this->readIndex;
 754         }
 755 }