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