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          * Bogus warning
  91          * @suppress PhanAccessMethodProtected
  92          *
  93          * @param array $config
  94          * @throws FileBackendError
  95          */
  96         public function __construct( array $config ) {
  97                 parent::__construct( $config );
  98                 $this->syncChecks = $config['syncChecks'] ?? self::CHECK_SIZE;
  99                 $this->autoResync = $config['autoResync'] ?? false;
 100                 $this->asyncWrites = isset( $config['replication'] ) && $config['replication'] === 'async';
 101                 // Construct backends here rather than via registration
 102                 // to keep these backends hidden from outside the proxy.
 103                 $namesUsed = [];
 104                 foreach ( $config['backends'] as $index => $config ) {
 105                         $name = $config['name'];
 106                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 107                                 throw new LogicException( "Two or more backends defined with the name $name." );
 108                         }
 109                         $namesUsed[$name] = 1;
 110                         // Alter certain sub-backend settings for sanity
 111                         unset( $config['readOnly'] ); // use proxy backend setting
 112                         unset( $config['fileJournal'] ); // use proxy backend journal
 113                         unset( $config['lockManager'] ); // lock under proxy backend
 114                         $config['domainId'] = $this->domainId; // use the proxy backend wiki ID
 115                         if ( !empty( $config['isMultiMaster'] ) ) {
 116                                 if ( $this->masterIndex >= 0 ) {
 117                                         throw new LogicException( 'More than one master backend defined.' );
 118                                 }
 119                                 $this->masterIndex = $index; // this is the "master"
 120                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 121                         }
 122                         if ( !empty( $config['readAffinity'] ) ) {
 123                                 $this->readIndex = $index; // prefer this for reads
 124                         }
 125                         // Create sub-backend object
 126                         if ( !isset( $config['class'] ) ) {
 127                                 throw new InvalidArgumentException( 'No class given for a backend config.' );
 128                         }
 129                         $class = $config['class'];
 130                         $this->backends[$index] = new $class( $config );
 131                 }
 132                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 133                         throw new LogicException( 'No master backend defined.' );
 134                 }
 135                 if ( $this->readIndex < 0 ) {
 136                         $this->readIndex = $this->masterIndex; // default
 137                 }
 138         }
 139
 140         final protected function doOperationsInternal( array $ops, array $opts ) {
 141                 $status = $this->newStatus();
 142
 143                 $mbe = $this->backends[$this->masterIndex]; // convenience
 144
 145                 // Try to lock those files for the scope of this function...
 146                 $scopeLock = null;
 147                 if ( empty( $opts['nonLocking'] ) ) {
 148                         // Try to lock those files for the scope of this function...
 149                         /** @noinspection PhpUnusedLocalVariableInspection */
 150                         $scopeLock = $this->getScopedLocksForOps( $ops, $status );
 151                         if ( !$status->isOK() ) {
 152                                 return $status; // abort
 153                         }
 154                 }
 155                 // Clear any cache entries (after locks acquired)
 156                 $this->clearCache();
 157                 $opts['preserveCache'] = true; // only locked files are cached
 158                 // Get the list of paths to read/write...
 159                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 160                 // Check if the paths are valid and accessible on all backends...
 161                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 162                 if ( !$status->isOK() ) {
 163                         return $status; // abort
 164                 }
 165                 // Do a consistency check to see if the backends are consistent...
 166                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 167                 if ( !$syncStatus->isOK() ) {
 168                         wfDebugLog( 'FileOperation', static::class .
 169                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 170                         // Try to resync the clone backends to the master on the spot...
 171                         if ( $this->autoResync === false
 172                                 || !$this->resyncFiles( $relevantPaths, $this->autoResync )->isOK()
 173                         ) {
 174                                 $status->merge( $syncStatus );
 175
 176                                 return $status; // abort
 177                         }
 178                 }
 179                 // Actually attempt the operation batch on the master backend...
 180                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 181                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 182                 $status->merge( $masterStatus );
 183                 // Propagate the operations to the clone backends if there were no unexpected errors
 184                 // and if there were either no expected errors or if the 'force' option was used.
 185                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 186                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 187                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 188                         foreach ( $this->backends as $index => $backend ) {
 189                                 if ( $index === $this->masterIndex ) {
 190                                         continue; // done already
 191                                 }
 192
 193                                 $realOps = $this->substOpBatchPaths( $ops, $backend );
 194                                 if ( $this->asyncWrites && !$this->hasVolatileSources( $ops ) ) {
 195                                         // Bind $scopeLock to the callback to preserve locks
 196                                         DeferredUpdates::addCallableUpdate(
 197                                                 function () use ( $backend, $realOps, $opts, $scopeLock, $relevantPaths ) {
 198                                                         wfDebugLog( 'FileOperationReplication',
 199                                                                 "'{$backend->getName()}' async replication; paths: " .
 200                                                                 FormatJson::encode( $relevantPaths ) );
 201                                                         $backend->doOperations( $realOps, $opts );
 202                                                 }
 203                                         );
 204                                 } else {
 205                                         wfDebugLog( 'FileOperationReplication',
 206                                                 "'{$backend->getName()}' sync replication; paths: " .
 207                                                 FormatJson::encode( $relevantPaths ) );
 208                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 209                                 }
 210                         }
 211                 }
 212                 // Make 'success', 'successCount', and 'failCount' fields reflect
 213                 // the overall operation, rather than all the batches for each backend.
 214                 // Do this by only using success values from the master backend's batch.
 215                 $status->success = $masterStatus->success;
 216                 $status->successCount = $masterStatus->successCount;
 217                 $status->failCount = $masterStatus->failCount;
 218
 219                 return $status;
 220         }
 221
 222         /**
 223          * Check that a set of files are consistent across all internal backends
 224          *
 225          * @param array $paths List of storage paths
 226          * @return StatusValue
 227          */
 228         public function consistencyCheck( array $paths ) {
 229                 $status = $this->newStatus();
 230                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 231                         return $status; // skip checks
 232                 }
 233
 234                 // Preload all of the stat info in as few round trips as possible...
 235                 foreach ( $this->backends as $backend ) {
 236                         $realPaths = $this->substPaths( $paths, $backend );
 237                         $backend->preloadFileStat( [ 'srcs' => $realPaths, 'latest' => true ] );
 238                 }
 239
 240                 $mBackend = $this->backends[$this->masterIndex];
 241                 foreach ( $paths as $path ) {
 242                         $params = [ 'src' => $path, 'latest' => true ];
 243                         $mParams = $this->substOpPaths( $params, $mBackend );
 244                         // Stat the file on the 'master' backend
 245                         $mStat = $mBackend->getFileStat( $mParams );
 246                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 247                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 248                         } else {
 249                                 $mSha1 = false;
 250                         }
 251                         // Check if all clone backends agree with the master...
 252                         foreach ( $this->backends as $index => $cBackend ) {
 253                                 if ( $index === $this->masterIndex ) {
 254                                         continue; // master
 255                                 }
 256                                 $cParams = $this->substOpPaths( $params, $cBackend );
 257                                 $cStat = $cBackend->getFileStat( $cParams );
 258                                 if ( $mStat ) { // file is in master
 259                                         if ( !$cStat ) { // file should exist
 260                                                 $status->fatal( 'backend-fail-synced', $path );
 261                                                 continue;
 262                                         }
 263                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 264                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 265                                                         $status->fatal( 'backend-fail-synced', $path );
 266                                                         continue;
 267                                                 }
 268                                         }
 269                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 270                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 271                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 272                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 273                                                         $status->fatal( 'backend-fail-synced', $path );
 274                                                         continue;
 275                                                 }
 276                                         }
 277                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 278                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 279                                                         $status->fatal( 'backend-fail-synced', $path );
 280                                                         continue;
 281                                                 }
 282                                         }
 283                                 } else { // file is not in master
 284                                         if ( $cStat ) { // file should not exist
 285                                                 $status->fatal( 'backend-fail-synced', $path );
 286                                         }
 287                                 }
 288                         }
 289                 }
 290
 291                 return $status;
 292         }
 293
 294         /**
 295          * Check that a set of file paths are usable across all internal backends
 296          *
 297          * @param array $paths List of storage paths
 298          * @return StatusValue
 299          */
 300         public function accessibilityCheck( array $paths ) {
 301                 $status = $this->newStatus();
 302                 if ( count( $this->backends ) <= 1 ) {
 303                         return $status; // skip checks
 304                 }
 305
 306                 foreach ( $paths as $path ) {
 307                         foreach ( $this->backends as $backend ) {
 308                                 $realPath = $this->substPaths( $path, $backend );
 309                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 310                                         $status->fatal( 'backend-fail-usable', $path );
 311                                 }
 312                         }
 313                 }
 314
 315                 return $status;
 316         }
 317
 318         /**
 319          * Check that a set of files are consistent across all internal backends
 320          * and re-synchronize those files against the "multi master" if needed.
 321          *
 322          * @param array $paths List of storage paths
 323          * @param string|bool $resyncMode False, True, or "conservative"; see __construct()
 324          * @return StatusValue
 325          */
 326         public function resyncFiles( array $paths, $resyncMode = true ) {
 327                 $status = $this->newStatus();
 328
 329                 $mBackend = $this->backends[$this->masterIndex];
 330                 foreach ( $paths as $path ) {
 331                         $mPath = $this->substPaths( $path, $mBackend );
 332                         $mSha1 = $mBackend->getFileSha1Base36( [ 'src' => $mPath, 'latest' => true ] );
 333                         $mStat = $mBackend->getFileStat( [ 'src' => $mPath, 'latest' => true ] );
 334                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 335                                 $status->fatal( 'backend-fail-internal', $this->name );
 336                                 wfDebugLog( 'FileOperation', __METHOD__
 337                                         . ': File is not available on the master backend' );
 338                                 continue; // file is not available on the master backend...
 339                         }
 340                         // Check of all clone backends agree with the master...
 341                         foreach ( $this->backends as $index => $cBackend ) {
 342                                 if ( $index === $this->masterIndex ) {
 343                                         continue; // master
 344                                 }
 345                                 $cPath = $this->substPaths( $path, $cBackend );
 346                                 $cSha1 = $cBackend->getFileSha1Base36( [ 'src' => $cPath, 'latest' => true ] );
 347                                 $cStat = $cBackend->getFileStat( [ 'src' => $cPath, 'latest' => true ] );
 348                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 349                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 350                                         wfDebugLog( 'FileOperation', __METHOD__ .
 351                                                 ': File is not available on the clone backend' );
 352                                         continue; // file is not available on the clone backend...
 353                                 }
 354                                 if ( $mSha1 === $cSha1 ) {
 355                                         // already synced; nothing to do
 356                                 } elseif ( $mSha1 !== false ) { // file is in master
 357                                         if ( $resyncMode === 'conservative'
 358                                                 && $cStat && $cStat['mtime'] > $mStat['mtime']
 359                                         ) {
 360                                                 $status->fatal( 'backend-fail-synced', $path );
 361                                                 continue; // don't rollback data
 362                                         }
 363                                         $fsFile = $mBackend->getLocalReference(
 364                                                 [ 'src' => $mPath, 'latest' => true ] );
 365                                         $status->merge( $cBackend->quickStore(
 366                                                 [ 'src' => $fsFile->getPath(), 'dst' => $cPath ]
 367                                         ) );
 368                                 } elseif ( $mStat === false ) { // file is not in master
 369                                         if ( $resyncMode === 'conservative' ) {
 370                                                 $status->fatal( 'backend-fail-synced', $path );
 371                                                 continue; // don't delete data
 372                                         }
 373                                         $status->merge( $cBackend->quickDelete( [ 'src' => $cPath ] ) );
 374                                 }
 375                         }
 376                 }
 377
 378                 if ( !$status->isOK() ) {
 379                         wfDebugLog( 'FileOperation', static::class .
 380                                 " failed to resync: " . FormatJson::encode( $paths ) );
 381                 }
 382
 383                 return $status;
 384         }
 385
 386         /**
 387          * Get a list of file storage paths to read or write for a list of operations
 388          *
 389          * @param array $ops Same format as doOperations()
 390          * @return array List of storage paths to files (does not include directories)
 391          */
 392         protected function fileStoragePathsForOps( array $ops ) {
 393                 $paths = [];
 394                 foreach ( $ops as $op ) {
 395                         if ( isset( $op['src'] ) ) {
 396                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 397                                 // is no source file, nothing should happen and there should be no errors.
 398                                 if ( empty( $op['ignoreMissingSource'] )
 399                                         || $this->fileExists( [ 'src' => $op['src'] ] )
 400                                 ) {
 401                                         $paths[] = $op['src'];
 402                                 }
 403                         }
 404                         if ( isset( $op['srcs'] ) ) {
 405                                 $paths = array_merge( $paths, $op['srcs'] );
 406                         }
 407                         if ( isset( $op['dst'] ) ) {
 408                                 $paths[] = $op['dst'];
 409                         }
 410                 }
 411
 412                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 413         }
 414
 415         /**
 416          * Substitute the backend name in storage path parameters
 417          * for a set of operations with that of a given internal backend.
 418          *
 419          * @param array $ops List of file operation arrays
 420          * @param FileBackendStore $backend
 421          * @return array
 422          */
 423         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 424                 $newOps = []; // operations
 425                 foreach ( $ops as $op ) {
 426                         $newOp = $op; // operation
 427                         foreach ( [ 'src', 'srcs', 'dst', 'dir' ] as $par ) {
 428                                 if ( isset( $newOp[$par] ) ) { // string or array
 429                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 430                                 }
 431                         }
 432                         $newOps[] = $newOp;
 433                 }
 434
 435                 return $newOps;
 436         }
 437
 438         /**
 439          * Same as substOpBatchPaths() but for a single operation
 440          *
 441          * @param array $ops File operation array
 442          * @param FileBackendStore $backend
 443          * @return array
 444          */
 445         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 446                 $newOps = $this->substOpBatchPaths( [ $ops ], $backend );
 447
 448                 return $newOps[0];
 449         }
 450
 451         /**
 452          * Substitute the backend of storage paths with an internal backend's name
 453          *
 454          * @param array|string $paths List of paths or single string path
 455          * @param FileBackendStore $backend
 456          * @return array|string
 457          */
 458         protected function substPaths( $paths, FileBackendStore $backend ) {
 459                 return preg_replace(
 460                         '!^mwstore://' . preg_quote( $this->name, '!' ) . '/!',
 461                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 462                         $paths // string or array
 463                 );
 464         }
 465
 466         /**
 467          * Substitute the backend of internal storage paths with the proxy backend's name
 468          *
 469          * @param array|string $paths List of paths or single string path
 470          * @return array|string
 471          */
 472         protected function unsubstPaths( $paths ) {
 473                 return preg_replace(
 474                         '!^mwstore://([^/]+)!',
 475                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 476                         $paths // string or array
 477                 );
 478         }
 479
 480         /**
 481          * @param array $ops File operations for FileBackend::doOperations()
 482          * @return bool Whether there are file path sources with outside lifetime/ownership
 483          */
 484         protected function hasVolatileSources( array $ops ) {
 485                 foreach ( $ops as $op ) {
 486                         if ( $op['op'] === 'store' && !isset( $op['srcRef'] ) ) {
 487                                 return true; // source file might be deleted anytime after do*Operations()
 488                         }
 489                 }
 490
 491                 return false;
 492         }
 493
 494         protected function doQuickOperationsInternal( array $ops ) {
 495                 $status = $this->newStatus();
 496                 // Do the operations on the master backend; setting StatusValue fields...
 497                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 498                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 499                 $status->merge( $masterStatus );
 500                 // Propagate the operations to the clone backends...
 501                 foreach ( $this->backends as $index => $backend ) {
 502                         if ( $index === $this->masterIndex ) {
 503                                 continue; // done already
 504                         }
 505
 506                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 507                         if ( $this->asyncWrites && !$this->hasVolatileSources( $ops ) ) {
 508                                 DeferredUpdates::addCallableUpdate(
 509                                         function () use ( $backend, $realOps ) {
 510                                                 $backend->doQuickOperations( $realOps );
 511                                         }
 512                                 );
 513                         } else {
 514                                 $status->merge( $backend->doQuickOperations( $realOps ) );
 515                         }
 516                 }
 517                 // Make 'success', 'successCount', and 'failCount' fields reflect
 518                 // the overall operation, rather than all the batches for each backend.
 519                 // Do this by only using success values from the master backend's batch.
 520                 $status->success = $masterStatus->success;
 521                 $status->successCount = $masterStatus->successCount;
 522                 $status->failCount = $masterStatus->failCount;
 523
 524                 return $status;
 525         }
 526
 527         protected function doPrepare( array $params ) {
 528                 return $this->doDirectoryOp( 'prepare', $params );
 529         }
 530
 531         protected function doSecure( array $params ) {
 532                 return $this->doDirectoryOp( 'secure', $params );
 533         }
 534
 535         protected function doPublish( array $params ) {
 536                 return $this->doDirectoryOp( 'publish', $params );
 537         }
 538
 539         protected function doClean( array $params ) {
 540                 return $this->doDirectoryOp( 'clean', $params );
 541         }
 542
 543         /**
 544          * @param string $method One of (doPrepare,doSecure,doPublish,doClean)
 545          * @param array $params Method arguments
 546          * @return StatusValue
 547          */
 548         protected function doDirectoryOp( $method, array $params ) {
 549                 $status = $this->newStatus();
 550
 551                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 552                 $masterStatus = $this->backends[$this->masterIndex]->$method( $realParams );
 553                 $status->merge( $masterStatus );
 554
 555                 foreach ( $this->backends as $index => $backend ) {
 556                         if ( $index === $this->masterIndex ) {
 557                                 continue; // already done
 558                         }
 559
 560                         $realParams = $this->substOpPaths( $params, $backend );
 561                         if ( $this->asyncWrites ) {
 562                                 DeferredUpdates::addCallableUpdate(
 563                                         function () use ( $backend, $method, $realParams ) {
 564                                                 $backend->$method( $realParams );
 565                                         }
 566                                 );
 567                         } else {
 568                                 $status->merge( $backend->$method( $realParams ) );
 569                         }
 570                 }
 571
 572                 return $status;
 573         }
 574
 575         public function concatenate( array $params ) {
 576                 $status = $this->newStatus();
 577                 // We are writing to an FS file, so we don't need to do this per-backend
 578                 $index = $this->getReadIndexFromParams( $params );
 579                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 580
 581                 $status->merge( $this->backends[$index]->concatenate( $realParams ) );
 582
 583                 return $status;
 584         }
 585
 586         public function fileExists( array $params ) {
 587                 $index = $this->getReadIndexFromParams( $params );
 588                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 589
 590                 return $this->backends[$index]->fileExists( $realParams );
 591         }
 592
 593         public function getFileTimestamp( array $params ) {
 594                 $index = $this->getReadIndexFromParams( $params );
 595                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 596
 597                 return $this->backends[$index]->getFileTimestamp( $realParams );
 598         }
 599
 600         public function getFileSize( array $params ) {
 601                 $index = $this->getReadIndexFromParams( $params );
 602                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 603
 604                 return $this->backends[$index]->getFileSize( $realParams );
 605         }
 606
 607         public function getFileStat( array $params ) {
 608                 $index = $this->getReadIndexFromParams( $params );
 609                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 610
 611                 return $this->backends[$index]->getFileStat( $realParams );
 612         }
 613
 614         public function getFileXAttributes( array $params ) {
 615                 $index = $this->getReadIndexFromParams( $params );
 616                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 617
 618                 return $this->backends[$index]->getFileXAttributes( $realParams );
 619         }
 620
 621         public function getFileContentsMulti( array $params ) {
 622                 $index = $this->getReadIndexFromParams( $params );
 623                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 624
 625                 $contentsM = $this->backends[$index]->getFileContentsMulti( $realParams );
 626
 627                 $contents = []; // (path => FSFile) mapping using the proxy backend's name
 628                 foreach ( $contentsM as $path => $data ) {
 629                         $contents[$this->unsubstPaths( $path )] = $data;
 630                 }
 631
 632                 return $contents;
 633         }
 634
 635         public function getFileSha1Base36( array $params ) {
 636                 $index = $this->getReadIndexFromParams( $params );
 637                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 638
 639                 return $this->backends[$index]->getFileSha1Base36( $realParams );
 640         }
 641
 642         public function getFileProps( array $params ) {
 643                 $index = $this->getReadIndexFromParams( $params );
 644                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 645
 646                 return $this->backends[$index]->getFileProps( $realParams );
 647         }
 648
 649         public function streamFile( array $params ) {
 650                 $index = $this->getReadIndexFromParams( $params );
 651                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 652
 653                 return $this->backends[$index]->streamFile( $realParams );
 654         }
 655
 656         public function getLocalReferenceMulti( array $params ) {
 657                 $index = $this->getReadIndexFromParams( $params );
 658                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 659
 660                 $fsFilesM = $this->backends[$index]->getLocalReferenceMulti( $realParams );
 661
 662                 $fsFiles = []; // (path => FSFile) mapping using the proxy backend's name
 663                 foreach ( $fsFilesM as $path => $fsFile ) {
 664                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 665                 }
 666
 667                 return $fsFiles;
 668         }
 669
 670         public function getLocalCopyMulti( array $params ) {
 671                 $index = $this->getReadIndexFromParams( $params );
 672                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 673
 674                 $tempFilesM = $this->backends[$index]->getLocalCopyMulti( $realParams );
 675
 676                 $tempFiles = []; // (path => TempFSFile) mapping using the proxy backend's name
 677                 foreach ( $tempFilesM as $path => $tempFile ) {
 678                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 679                 }
 680
 681                 return $tempFiles;
 682         }
 683
 684         public function getFileHttpUrl( array $params ) {
 685                 $index = $this->getReadIndexFromParams( $params );
 686                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 687
 688                 return $this->backends[$index]->getFileHttpUrl( $realParams );
 689         }
 690
 691         public function directoryExists( array $params ) {
 692                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 693
 694                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 695         }
 696
 697         public function getDirectoryList( array $params ) {
 698                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 699
 700                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 701         }
 702
 703         public function getFileList( array $params ) {
 704                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 705
 706                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 707         }
 708
 709         public function getFeatures() {
 710                 return $this->backends[$this->masterIndex]->getFeatures();
 711         }
 712
 713         public function clearCache( array $paths = null ) {
 714                 foreach ( $this->backends as $backend ) {
 715                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 716                         $backend->clearCache( $realPaths );
 717                 }
 718         }
 719
 720         public function preloadCache( array $paths ) {
 721                 $realPaths = $this->substPaths( $paths, $this->backends[$this->readIndex] );
 722                 $this->backends[$this->readIndex]->preloadCache( $realPaths );
 723         }
 724
 725         public function preloadFileStat( array $params ) {
 726                 $index = $this->getReadIndexFromParams( $params );
 727                 $realParams = $this->substOpPaths( $params, $this->backends[$index] );
 728
 729                 return $this->backends[$index]->preloadFileStat( $realParams );
 730         }
 731
 732         public function getScopedLocksForOps( array $ops, StatusValue $status ) {
 733                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 734                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $realOps );
 735                 // Get the paths to lock from the master backend
 736                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 737                 // Get the paths under the proxy backend's name
 738                 $pbPaths = [
 739                         LockManager::LOCK_UW => $this->unsubstPaths( $paths[LockManager::LOCK_UW] ),
 740                         LockManager::LOCK_EX => $this->unsubstPaths( $paths[LockManager::LOCK_EX] )
 741                 ];
 742
 743                 // Actually acquire the locks
 744                 return $this->getScopedFileLocks( $pbPaths, 'mixed', $status );
 745         }
 746
 747         /**
 748          * @param array $params
 749          * @return int The master or read affinity backend index, based on $params['latest']
 750          */
 751         protected function getReadIndexFromParams( array $params ) {
 752                 return !empty( $params['latest'] ) ? $this->masterIndex : $this->readIndex;
 753         }
 754 }