includes/filerepo/backend/FileBackendStore.php

   1 <?php
   2 /**
   3  * @file
   4  * @ingroup FileBackend
   5  * @author Aaron Schulz
   6  */
   7
   8 /**
   9  * @brief Base class for all backends using particular storage medium.
  10  *
  11  * This class defines the methods as abstract that subclasses must implement.
  12  * Outside callers should *not* use functions with "Internal" in the name.
  13  *
  14  * The FileBackend operations are implemented using basic functions
  15  * such as storeInternal(), copyInternal(), deleteInternal() and the like.
  16  * This class is also responsible for path resolution and sanitization.
  17  *
  18  * @ingroup FileBackend
  19  * @since 1.19
  20  */
  21 abstract class FileBackendStore extends FileBackend {
  22         /** @var Array Map of paths to small (RAM/disk) cache items */
  23         protected $cache = array(); // (storage path => key => value)
  24         protected $maxCacheSize = 100; // integer; max paths with entries
  25         /** @var Array Map of paths to large (RAM/disk) cache items */
  26         protected $expensiveCache = array(); // (storage path => key => value)
  27         protected $maxExpensiveCacheSize = 10; // integer; max paths with entries
  28
  29         /** @var Array Map of container names to sharding settings */
  30         protected $shardViaHashLevels = array(); // (container name => config array)
  31
  32         protected $maxFileSize = 1000000000; // integer bytes (1GB)
  33
  34         /**
  35          * Get the maximum allowable file size given backend
  36          * medium restrictions and basic performance constraints.
  37          * Do not call this function from places outside FileBackend and FileOp.
  38          *
  39          * @return integer Bytes
  40          */
  41         final public function maxFileSizeInternal() {
  42                 return $this->maxFileSize;
  43         }
  44
  45         /**
  46          * Check if a file can be created at a given storage path.
  47          * FS backends should check if the parent directory exists and the file is writable.
  48          * Backends using key/value stores should check if the container exists.
  49          *
  50          * @param $storagePath string
  51          * @return bool
  52          */
  53         abstract public function isPathUsableInternal( $storagePath );
  54
  55         /**
  56          * Create a file in the backend with the given contents.
  57          * Do not call this function from places outside FileBackend and FileOp.
  58          *
  59          * $params include:
  60          *     content       : the raw file contents
  61          *     dst           : destination storage path
  62          *     overwrite     : overwrite any file that exists at the destination
  63          *
  64          * @param $params Array
  65          * @return Status
  66          */
  67         final public function createInternal( array $params ) {
  68                 wfProfileIn( __METHOD__ );
  69                 if ( strlen( $params['content'] ) > $this->maxFileSizeInternal() ) {
  70                         $status = Status::newFatal( 'backend-fail-create', $params['dst'] );
  71                 } else {
  72                         $status = $this->doCreateInternal( $params );
  73                         $this->clearCache( array( $params['dst'] ) );
  74                 }
  75                 wfProfileOut( __METHOD__ );
  76                 return $status;
  77         }
  78
  79         /**
  80          * @see FileBackendStore::createInternal()
  81          */
  82         abstract protected function doCreateInternal( array $params );
  83
  84         /**
  85          * Store a file into the backend from a file on disk.
  86          * Do not call this function from places outside FileBackend and FileOp.
  87          *
  88          * $params include:
  89          *     src           : source path on disk
  90          *     dst           : destination storage path
  91          *     overwrite     : overwrite any file that exists at the destination
  92          *
  93          * @param $params Array
  94          * @return Status
  95          */
  96         final public function storeInternal( array $params ) {
  97                 wfProfileIn( __METHOD__ );
  98                 if ( filesize( $params['src'] ) > $this->maxFileSizeInternal() ) {
  99                         $status = Status::newFatal( 'backend-fail-store', $params['dst'] );
 100                 } else {
 101                         $status = $this->doStoreInternal( $params );
 102                         $this->clearCache( array( $params['dst'] ) );
 103                 }
 104                 wfProfileOut( __METHOD__ );
 105                 return $status;
 106         }
 107
 108         /**
 109          * @see FileBackendStore::storeInternal()
 110          */
 111         abstract protected function doStoreInternal( array $params );
 112
 113         /**
 114          * Copy a file from one storage path to another in the backend.
 115          * Do not call this function from places outside FileBackend and FileOp.
 116          *
 117          * $params include:
 118          *     src           : source storage path
 119          *     dst           : destination storage path
 120          *     overwrite     : overwrite any file that exists at the destination
 121          *
 122          * @param $params Array
 123          * @return Status
 124          */
 125         final public function copyInternal( array $params ) {
 126                 wfProfileIn( __METHOD__ );
 127                 $status = $this->doCopyInternal( $params );
 128                 $this->clearCache( array( $params['dst'] ) );
 129                 wfProfileOut( __METHOD__ );
 130                 return $status;
 131         }
 132
 133         /**
 134          * @see FileBackendStore::copyInternal()
 135          */
 136         abstract protected function doCopyInternal( array $params );
 137
 138         /**
 139          * Delete a file at the storage path.
 140          * Do not call this function from places outside FileBackend and FileOp.
 141          *
 142          * $params include:
 143          *     src                 : source storage path
 144          *     ignoreMissingSource : do nothing if the source file does not exist
 145          *
 146          * @param $params Array
 147          * @return Status
 148          */
 149         final public function deleteInternal( array $params ) {
 150                 wfProfileIn( __METHOD__ );
 151                 $status = $this->doDeleteInternal( $params );
 152                 $this->clearCache( array( $params['src'] ) );
 153                 wfProfileOut( __METHOD__ );
 154                 return $status;
 155         }
 156
 157         /**
 158          * @see FileBackendStore::deleteInternal()
 159          */
 160         abstract protected function doDeleteInternal( array $params );
 161
 162         /**
 163          * Move a file from one storage path to another in the backend.
 164          * Do not call this function from places outside FileBackend and FileOp.
 165          *
 166          * $params include:
 167          *     src           : source storage path
 168          *     dst           : destination storage path
 169          *     overwrite     : overwrite any file that exists at the destination
 170          *
 171          * @param $params Array
 172          * @return Status
 173          */
 174         final public function moveInternal( array $params ) {
 175                 wfProfileIn( __METHOD__ );
 176                 $status = $this->doMoveInternal( $params );
 177                 $this->clearCache( array( $params['src'], $params['dst'] ) );
 178                 wfProfileOut( __METHOD__ );
 179                 return $status;
 180         }
 181
 182         /**
 183          * @see FileBackendStore::moveInternal()
 184          * @return Status
 185          */
 186         protected function doMoveInternal( array $params ) {
 187                 // Copy source to dest
 188                 $status = $this->copyInternal( $params );
 189                 if ( $status->isOK() ) {
 190                         // Delete source (only fails due to races or medium going down)
 191                         $status->merge( $this->deleteInternal( array( 'src' => $params['src'] ) ) );
 192                         $status->setResult( true, $status->value ); // ignore delete() errors
 193                 }
 194                 return $status;
 195         }
 196
 197         /**
 198          * @see FileBackend::concatenate()
 199          * @return Status
 200          */
 201         final public function concatenate( array $params ) {
 202                 wfProfileIn( __METHOD__ );
 203                 $status = Status::newGood();
 204
 205                 // Try to lock the source files for the scope of this function
 206                 $scopeLockS = $this->getScopedFileLocks( $params['srcs'], LockManager::LOCK_UW, $status );
 207                 if ( $status->isOK() ) {
 208                         // Actually do the concatenation
 209                         $status->merge( $this->doConcatenate( $params ) );
 210                 }
 211
 212                 wfProfileOut( __METHOD__ );
 213                 return $status;
 214         }
 215
 216         /**
 217          * @see FileBackendStore::concatenate()
 218          * @return Status
 219          */
 220         protected function doConcatenate( array $params ) {
 221                 $status = Status::newGood();
 222                 $tmpPath = $params['dst']; // convenience
 223
 224                 // Check that the specified temp file is valid...
 225                 wfSuppressWarnings();
 226                 $ok = ( is_file( $tmpPath ) && !filesize( $tmpPath ) );
 227                 wfRestoreWarnings();
 228                 if ( !$ok ) { // not present or not empty
 229                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 230                         return $status;
 231                 }
 232
 233                 // Build up the temp file using the source chunks (in order)...
 234                 $tmpHandle = fopen( $tmpPath, 'ab' );
 235                 if ( $tmpHandle === false ) {
 236                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 237                         return $status;
 238                 }
 239                 foreach ( $params['srcs'] as $virtualSource ) {
 240                         // Get a local FS version of the chunk
 241                         $tmpFile = $this->getLocalReference( array( 'src' => $virtualSource ) );
 242                         if ( !$tmpFile ) {
 243                                 $status->fatal( 'backend-fail-read', $virtualSource );
 244                                 return $status;
 245                         }
 246                         // Get a handle to the local FS version
 247                         $sourceHandle = fopen( $tmpFile->getPath(), 'r' );
 248                         if ( $sourceHandle === false ) {
 249                                 fclose( $tmpHandle );
 250                                 $status->fatal( 'backend-fail-read', $virtualSource );
 251                                 return $status;
 252                         }
 253                         // Append chunk to file (pass chunk size to avoid magic quotes)
 254                         if ( !stream_copy_to_stream( $sourceHandle, $tmpHandle ) ) {
 255                                 fclose( $sourceHandle );
 256                                 fclose( $tmpHandle );
 257                                 $status->fatal( 'backend-fail-writetemp', $tmpPath );
 258                                 return $status;
 259                         }
 260                         fclose( $sourceHandle );
 261                 }
 262                 if ( !fclose( $tmpHandle ) ) {
 263                         $status->fatal( 'backend-fail-closetemp', $tmpPath );
 264                         return $status;
 265                 }
 266
 267                 clearstatcache(); // temp file changed
 268
 269                 return $status;
 270         }
 271
 272         /**
 273          * @see FileBackend::doPrepare()
 274          * @return Status
 275          */
 276         final protected function doPrepare( array $params ) {
 277                 wfProfileIn( __METHOD__ );
 278
 279                 $status = Status::newGood();
 280                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 281                 if ( $dir === null ) {
 282                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 283                         wfProfileOut( __METHOD__ );
 284                         return $status; // invalid storage path
 285                 }
 286
 287                 if ( $shard !== null ) { // confined to a single container/shard
 288                         $status->merge( $this->doPrepareInternal( $fullCont, $dir, $params ) );
 289                 } else { // directory is on several shards
 290                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 291                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 292                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 293                                 $status->merge( $this->doPrepareInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 294                         }
 295                 }
 296
 297                 wfProfileOut( __METHOD__ );
 298                 return $status;
 299         }
 300
 301         /**
 302          * @see FileBackendStore::doPrepare()
 303          * @return Status
 304          */
 305         protected function doPrepareInternal( $container, $dir, array $params ) {
 306                 return Status::newGood();
 307         }
 308
 309         /**
 310          * @see FileBackend::doSecure()
 311          * @return Status
 312          */
 313         final protected function doSecure( array $params ) {
 314                 wfProfileIn( __METHOD__ );
 315                 $status = Status::newGood();
 316
 317                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 318                 if ( $dir === null ) {
 319                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 320                         wfProfileOut( __METHOD__ );
 321                         return $status; // invalid storage path
 322                 }
 323
 324                 if ( $shard !== null ) { // confined to a single container/shard
 325                         $status->merge( $this->doSecureInternal( $fullCont, $dir, $params ) );
 326                 } else { // directory is on several shards
 327                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 328                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 329                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 330                                 $status->merge( $this->doSecureInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 331                         }
 332                 }
 333
 334                 wfProfileOut( __METHOD__ );
 335                 return $status;
 336         }
 337
 338         /**
 339          * @see FileBackendStore::doSecure()
 340          * @return Status
 341          */
 342         protected function doSecureInternal( $container, $dir, array $params ) {
 343                 return Status::newGood();
 344         }
 345
 346         /**
 347          * @see FileBackend::doClean()
 348          * @return Status
 349          */
 350         final protected function doClean( array $params ) {
 351                 wfProfileIn( __METHOD__ );
 352                 $status = Status::newGood();
 353
 354                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 355                 if ( $dir === null ) {
 356                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 357                         wfProfileOut( __METHOD__ );
 358                         return $status; // invalid storage path
 359                 }
 360
 361                 // Attempt to lock this directory...
 362                 $filesLockEx = array( $params['dir'] );
 363                 $scopedLockE = $this->getScopedFileLocks( $filesLockEx, LockManager::LOCK_EX, $status );
 364                 if ( !$status->isOK() ) {
 365                         wfProfileOut( __METHOD__ );
 366                         return $status; // abort
 367                 }
 368
 369                 if ( $shard !== null ) { // confined to a single container/shard
 370                         $status->merge( $this->doCleanInternal( $fullCont, $dir, $params ) );
 371                 } else { // directory is on several shards
 372                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 373                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 374                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 375                                 $status->merge( $this->doCleanInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 376                         }
 377                 }
 378
 379                 wfProfileOut( __METHOD__ );
 380                 return $status;
 381         }
 382
 383         /**
 384          * @see FileBackendStore::doClean()
 385          * @return Status
 386          */
 387         protected function doCleanInternal( $container, $dir, array $params ) {
 388                 return Status::newGood();
 389         }
 390
 391         /**
 392          * @see FileBackend::fileExists()
 393          * @return bool|null
 394          */
 395         final public function fileExists( array $params ) {
 396                 wfProfileIn( __METHOD__ );
 397                 $stat = $this->getFileStat( $params );
 398                 wfProfileOut( __METHOD__ );
 399                 return ( $stat === null ) ? null : (bool)$stat; // null => failure
 400         }
 401
 402         /**
 403          * @see FileBackend::getFileTimestamp()
 404          * @return bool
 405          */
 406         final public function getFileTimestamp( array $params ) {
 407                 wfProfileIn( __METHOD__ );
 408                 $stat = $this->getFileStat( $params );
 409                 wfProfileOut( __METHOD__ );
 410                 return $stat ? $stat['mtime'] : false;
 411         }
 412
 413         /**
 414          * @see FileBackend::getFileSize()
 415          * @return bool
 416          */
 417         final public function getFileSize( array $params ) {
 418                 wfProfileIn( __METHOD__ );
 419                 $stat = $this->getFileStat( $params );
 420                 wfProfileOut( __METHOD__ );
 421                 return $stat ? $stat['size'] : false;
 422         }
 423
 424         /**
 425          * @see FileBackend::getFileStat()
 426          * @return bool
 427          */
 428         final public function getFileStat( array $params ) {
 429                 wfProfileIn( __METHOD__ );
 430                 $path = self::normalizeStoragePath( $params['src'] );
 431                 if ( $path === null ) {
 432                         wfProfileOut( __METHOD__ );
 433                         return false; // invalid storage path
 434                 }
 435                 $latest = !empty( $params['latest'] );
 436                 if ( isset( $this->cache[$path]['stat'] ) ) {
 437                         // If we want the latest data, check that this cached
 438                         // value was in fact fetched with the latest available data.
 439                         if ( !$latest || $this->cache[$path]['stat']['latest'] ) {
 440                                 wfProfileOut( __METHOD__ );
 441                                 return $this->cache[$path]['stat'];
 442                         }
 443                 }
 444                 wfProfileIn( __METHOD__ . '-miss' );
 445                 $stat = $this->doGetFileStat( $params );
 446                 wfProfileOut( __METHOD__ . '-miss' );
 447                 if ( is_array( $stat ) ) { // don't cache negatives
 448                         $this->trimCache(); // limit memory
 449                         $this->cache[$path]['stat'] = $stat;
 450                         $this->cache[$path]['stat']['latest'] = $latest;
 451                 }
 452                 wfProfileOut( __METHOD__ );
 453                 return $stat;
 454         }
 455
 456         /**
 457          * @see FileBackendStore::getFileStat()
 458          */
 459         abstract protected function doGetFileStat( array $params );
 460
 461         /**
 462          * @see FileBackend::getFileContents()
 463          * @return bool|string
 464          */
 465         public function getFileContents( array $params ) {
 466                 wfProfileIn( __METHOD__ );
 467                 $tmpFile = $this->getLocalReference( $params );
 468                 if ( !$tmpFile ) {
 469                         wfProfileOut( __METHOD__ );
 470                         return false;
 471                 }
 472                 wfSuppressWarnings();
 473                 $data = file_get_contents( $tmpFile->getPath() );
 474                 wfRestoreWarnings();
 475                 wfProfileOut( __METHOD__ );
 476                 return $data;
 477         }
 478
 479         /**
 480          * @see FileBackend::getFileSha1Base36()
 481          * @return bool|string
 482          */
 483         final public function getFileSha1Base36( array $params ) {
 484                 wfProfileIn( __METHOD__ );
 485                 $path = $params['src'];
 486                 if ( isset( $this->cache[$path]['sha1'] ) ) {
 487                         wfProfileOut( __METHOD__ );
 488                         return $this->cache[$path]['sha1'];
 489                 }
 490                 wfProfileIn( __METHOD__ . '-miss' );
 491                 $hash = $this->doGetFileSha1Base36( $params );
 492                 wfProfileOut( __METHOD__ . '-miss' );
 493                 if ( $hash ) { // don't cache negatives
 494                         $this->trimCache(); // limit memory
 495                         $this->cache[$path]['sha1'] = $hash;
 496                 }
 497                 wfProfileOut( __METHOD__ );
 498                 return $hash;
 499         }
 500
 501         /**
 502          * @see FileBackendStore::getFileSha1Base36()
 503          * @return bool
 504          */
 505         protected function doGetFileSha1Base36( array $params ) {
 506                 $fsFile = $this->getLocalReference( $params );
 507                 if ( !$fsFile ) {
 508                         return false;
 509                 } else {
 510                         return $fsFile->getSha1Base36();
 511                 }
 512         }
 513
 514         /**
 515          * @see FileBackend::getFileProps()
 516          * @return Array
 517          */
 518         final public function getFileProps( array $params ) {
 519                 wfProfileIn( __METHOD__ );
 520                 $fsFile = $this->getLocalReference( $params );
 521                 $props = $fsFile ? $fsFile->getProps() : FSFile::placeholderProps();
 522                 wfProfileOut( __METHOD__ );
 523                 return $props;
 524         }
 525
 526         /**
 527          * @see FileBackend::getLocalReference()
 528          * @return TempFSFile|null
 529          */
 530         public function getLocalReference( array $params ) {
 531                 wfProfileIn( __METHOD__ );
 532                 $path = $params['src'];
 533                 if ( isset( $this->expensiveCache[$path]['localRef'] ) ) {
 534                         wfProfileOut( __METHOD__ );
 535                         return $this->expensiveCache[$path]['localRef'];
 536                 }
 537                 $tmpFile = $this->getLocalCopy( $params );
 538                 if ( $tmpFile ) { // don't cache negatives
 539                         $this->trimExpensiveCache(); // limit memory
 540                         $this->expensiveCache[$path]['localRef'] = $tmpFile;
 541                 }
 542                 wfProfileOut( __METHOD__ );
 543                 return $tmpFile;
 544         }
 545
 546         /**
 547          * @see FileBackend::streamFile()
 548          * @return Status
 549          */
 550         final public function streamFile( array $params ) {
 551                 wfProfileIn( __METHOD__ );
 552                 $status = Status::newGood();
 553
 554                 $info = $this->getFileStat( $params );
 555                 if ( !$info ) { // let StreamFile handle the 404
 556                         $status->fatal( 'backend-fail-notexists', $params['src'] );
 557                 }
 558
 559                 // Set output buffer and HTTP headers for stream
 560                 $extraHeaders = isset( $params['headers'] ) ? $params['headers'] : array();
 561                 $res = StreamFile::prepareForStream( $params['src'], $info, $extraHeaders );
 562                 if ( $res == StreamFile::NOT_MODIFIED ) {
 563                         // do nothing; client cache is up to date
 564                 } elseif ( $res == StreamFile::READY_STREAM ) {
 565                         wfProfileIn( __METHOD__ . '-send' );
 566                         $status = $this->doStreamFile( $params );
 567                         wfProfileOut( __METHOD__ . '-send' );
 568                 } else {
 569                         $status->fatal( 'backend-fail-stream', $params['src'] );
 570                 }
 571
 572                 wfProfileOut( __METHOD__ );
 573                 return $status;
 574         }
 575
 576         /**
 577          * @see FileBackendStore::streamFile()
 578          * @return Status
 579          */
 580         protected function doStreamFile( array $params ) {
 581                 $status = Status::newGood();
 582
 583                 $fsFile = $this->getLocalReference( $params );
 584                 if ( !$fsFile ) {
 585                         $status->fatal( 'backend-fail-stream', $params['src'] );
 586                 } elseif ( !readfile( $fsFile->getPath() ) ) {
 587                         $status->fatal( 'backend-fail-stream', $params['src'] );
 588                 }
 589
 590                 return $status;
 591         }
 592
 593         /**
 594          * @copydoc FileBackend::getFileList()
 595          * @return Array|null|Traversable
 596          */
 597         final public function getFileList( array $params ) {
 598                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 599                 if ( $dir === null ) { // invalid storage path
 600                         return null;
 601                 }
 602                 if ( $shard !== null ) {
 603                         // File listing is confined to a single container/shard
 604                         return $this->getFileListInternal( $fullCont, $dir, $params );
 605                 } else {
 606                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 607                         // File listing spans multiple containers/shards
 608                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 609                         return new FileBackendStoreShardListIterator( $this,
 610                                 $fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
 611                 }
 612         }
 613
 614         /**
 615          * Do not call this function from places outside FileBackend
 616          *
 617          * @see FileBackendStore::getFileList()
 618          *
 619          * @param $container string Resolved container name
 620          * @param $dir string Resolved path relative to container
 621          * @param $params Array
 622          * @return Traversable|Array|null
 623          */
 624         abstract public function getFileListInternal( $container, $dir, array $params );
 625
 626         /**
 627          * Get the list of supported operations and their corresponding FileOp classes.
 628          *
 629          * @return Array
 630          */
 631         protected function supportedOperations() {
 632                 return array(
 633                         'store'       => 'StoreFileOp',
 634                         'copy'        => 'CopyFileOp',
 635                         'move'        => 'MoveFileOp',
 636                         'delete'      => 'DeleteFileOp',
 637                         'create'      => 'CreateFileOp',
 638                         'null'        => 'NullFileOp'
 639                 );
 640         }
 641
 642         /**
 643          * Return a list of FileOp objects from a list of operations.
 644          * Do not call this function from places outside FileBackend.
 645          *
 646          * The result must have the same number of items as the input.
 647          * An exception is thrown if an unsupported operation is requested.
 648          *
 649          * @param $ops Array Same format as doOperations()
 650          * @return Array List of FileOp objects
 651          * @throws MWException
 652          */
 653         final public function getOperations( array $ops ) {
 654                 $supportedOps = $this->supportedOperations();
 655
 656                 $performOps = array(); // array of FileOp objects
 657                 // Build up ordered array of FileOps...
 658                 foreach ( $ops as $operation ) {
 659                         $opName = $operation['op'];
 660                         if ( isset( $supportedOps[$opName] ) ) {
 661                                 $class = $supportedOps[$opName];
 662                                 // Get params for this operation
 663                                 $params = $operation;
 664                                 // Append the FileOp class
 665                                 $performOps[] = new $class( $this, $params );
 666                         } else {
 667                                 throw new MWException( "Operation `$opName` is not supported." );
 668                         }
 669                 }
 670
 671                 return $performOps;
 672         }
 673
 674         /**
 675          * @see FileBackend::doOperationsInternal()
 676          * @return Status
 677          */
 678         protected function doOperationsInternal( array $ops, array $opts ) {
 679                 wfProfileIn( __METHOD__ );
 680                 $status = Status::newGood();
 681
 682                 // Build up a list of FileOps...
 683                 $performOps = $this->getOperations( $ops );
 684
 685                 // Acquire any locks as needed...
 686                 if ( empty( $opts['nonLocking'] ) ) {
 687                         // Build up a list of files to lock...
 688                         $filesLockEx = $filesLockSh = array();
 689                         foreach ( $performOps as $fileOp ) {
 690                                 $filesLockSh = array_merge( $filesLockSh, $fileOp->storagePathsRead() );
 691                                 $filesLockEx = array_merge( $filesLockEx, $fileOp->storagePathsChanged() );
 692                         }
 693                         // Optimization: if doing an EX lock anyway, don't also set an SH one
 694                         $filesLockSh = array_diff( $filesLockSh, $filesLockEx );
 695                         // Get a shared lock on the parent directory of each path changed
 696                         $filesLockSh = array_merge( $filesLockSh, array_map( 'dirname', $filesLockEx ) );
 697                         // Try to lock those files for the scope of this function...
 698                         $scopeLockS = $this->getScopedFileLocks( $filesLockSh, LockManager::LOCK_UW, $status );
 699                         $scopeLockE = $this->getScopedFileLocks( $filesLockEx, LockManager::LOCK_EX, $status );
 700                         if ( !$status->isOK() ) {
 701                                 wfProfileOut( __METHOD__ );
 702                                 return $status; // abort
 703                         }
 704                 }
 705
 706                 // Clear any cache entries (after locks acquired)
 707                 $this->clearCache();
 708
 709                 // Actually attempt the operation batch...
 710                 $subStatus = FileOp::attemptBatch( $performOps, $opts );
 711
 712                 // Merge errors into status fields
 713                 $status->merge( $subStatus );
 714                 $status->success = $subStatus->success; // not done in merge()
 715
 716                 wfProfileOut( __METHOD__ );
 717                 return $status;
 718         }
 719
 720         /**
 721          * @see FileBackend::clearCache()
 722          */
 723         final public function clearCache( array $paths = null ) {
 724                 if ( is_array( $paths ) ) {
 725                         $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
 726                         $paths = array_filter( $paths, 'strlen' ); // remove nulls
 727                 }
 728                 if ( $paths === null ) {
 729                         $this->cache = array();
 730                         $this->expensiveCache = array();
 731                 } else {
 732                         foreach ( $paths as $path ) {
 733                                 unset( $this->cache[$path] );
 734                                 unset( $this->expensiveCache[$path] );
 735                         }
 736                 }
 737                 $this->doClearCache( $paths );
 738         }
 739
 740         /**
 741          * Clears any additional stat caches for storage paths
 742          *
 743          * @see FileBackend::clearCache()
 744          *
 745          * @param $paths Array Storage paths (optional)
 746          * @return void
 747          */
 748         protected function doClearCache( array $paths = null ) {}
 749
 750         /**
 751          * Prune the inexpensive cache if it is too big to add an item
 752          *
 753          * @return void
 754          */
 755         protected function trimCache() {
 756                 if ( count( $this->cache ) >= $this->maxCacheSize ) {
 757                         reset( $this->cache );
 758                         unset( $this->cache[key( $this->cache )] );
 759                 }
 760         }
 761
 762         /**
 763          * Prune the expensive cache if it is too big to add an item
 764          *
 765          * @return void
 766          */
 767         protected function trimExpensiveCache() {
 768                 if ( count( $this->expensiveCache ) >= $this->maxExpensiveCacheSize ) {
 769                         reset( $this->expensiveCache );
 770                         unset( $this->expensiveCache[key( $this->expensiveCache )] );
 771                 }
 772         }
 773
 774         /**
 775          * Check if a container name is valid.
 776          * This checks for for length and illegal characters.
 777          *
 778          * @param $container string
 779          * @return bool
 780          */
 781         final protected static function isValidContainerName( $container ) {
 782                 // This accounts for Swift and S3 restrictions while leaving room
 783                 // for things like '.xxx' (hex shard chars) or '.seg' (segments).
 784                 // This disallows directory separators or traversal characters.
 785                 // Note that matching strings URL encode to the same string;
 786                 // in Swift, the length restriction is *after* URL encoding.
 787                 return preg_match( '/^[a-z0-9][a-z0-9-_]{0,199}$/i', $container );
 788         }
 789
 790         /**
 791          * Splits a storage path into an internal container name,
 792          * an internal relative file name, and a container shard suffix.
 793          * Any shard suffix is already appended to the internal container name.
 794          * This also checks that the storage path is valid and within this backend.
 795          *
 796          * If the container is sharded but a suffix could not be determined,
 797          * this means that the path can only refer to a directory and can only
 798          * be scanned by looking in all the container shards.
 799          *
 800          * @param $storagePath string
 801          * @return Array (container, path, container suffix) or (null, null, null) if invalid
 802          */
 803         final protected function resolveStoragePath( $storagePath ) {
 804                 list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
 805                 if ( $backend === $this->name ) { // must be for this backend
 806                         $relPath = self::normalizeContainerPath( $relPath );
 807                         if ( $relPath !== null ) {
 808                                 // Get shard for the normalized path if this container is sharded
 809                                 $cShard = $this->getContainerShard( $container, $relPath );
 810                                 // Validate and sanitize the relative path (backend-specific)
 811                                 $relPath = $this->resolveContainerPath( $container, $relPath );
 812                                 if ( $relPath !== null ) {
 813                                         // Prepend any wiki ID prefix to the container name
 814                                         $container = $this->fullContainerName( $container );
 815                                         if ( self::isValidContainerName( $container ) ) {
 816                                                 // Validate and sanitize the container name (backend-specific)
 817                                                 $container = $this->resolveContainerName( "{$container}{$cShard}" );
 818                                                 if ( $container !== null ) {
 819                                                         return array( $container, $relPath, $cShard );
 820                                                 }
 821                                         }
 822                                 }
 823                         }
 824                 }
 825                 return array( null, null, null );
 826         }
 827
 828         /**
 829          * Like resolveStoragePath() except null values are returned if
 830          * the container is sharded and the shard could not be determined.
 831          *
 832          * @see FileBackendStore::resolveStoragePath()
 833          *
 834          * @param $storagePath string
 835          * @return Array (container, path) or (null, null) if invalid
 836          */
 837         final protected function resolveStoragePathReal( $storagePath ) {
 838                 list( $container, $relPath, $cShard ) = $this->resolveStoragePath( $storagePath );
 839                 if ( $cShard !== null ) {
 840                         return array( $container, $relPath );
 841                 }
 842                 return array( null, null );
 843         }
 844
 845         /**
 846          * Get the container name shard suffix for a given path.
 847          * Any empty suffix means the container is not sharded.
 848          *
 849          * @param $container string Container name
 850          * @param $relStoragePath string Storage path relative to the container
 851          * @return string|null Returns null if shard could not be determined
 852          */
 853         final protected function getContainerShard( $container, $relPath ) {
 854                 list( $levels, $base, $repeat ) = $this->getContainerHashLevels( $container );
 855                 if ( $levels == 1 || $levels == 2 ) {
 856                         // Hash characters are either base 16 or 36
 857                         $char = ( $base == 36 ) ? '[0-9a-z]' : '[0-9a-f]';
 858                         // Get a regex that represents the shard portion of paths.
 859                         // The concatenation of the captures gives us the shard.
 860                         if ( $levels === 1 ) { // 16 or 36 shards per container
 861                                 $hashDirRegex = '(' . $char . ')';
 862                         } else { // 256 or 1296 shards per container
 863                                 if ( $repeat ) { // verbose hash dir format (e.g. "a/ab/abc")
 864                                         $hashDirRegex = $char . '/(' . $char . '{2})';
 865                                 } else { // short hash dir format (e.g. "a/b/c")
 866                                         $hashDirRegex = '(' . $char . ')/(' . $char . ')';
 867                                 }
 868                         }
 869                         // Allow certain directories to be above the hash dirs so as
 870                         // to work with FileRepo (e.g. "archive/a/ab" or "temp/a/ab").
 871                         // They must be 2+ chars to avoid any hash directory ambiguity.
 872                         $m = array();
 873                         if ( preg_match( "!^(?:[^/]{2,}/)*$hashDirRegex(?:/|$)!", $relPath, $m ) ) {
 874                                 return '.' . implode( '', array_slice( $m, 1 ) );
 875                         }
 876                         return null; // failed to match
 877                 }
 878                 return ''; // no sharding
 879         }
 880
 881         /**
 882          * Get the sharding config for a container.
 883          * If greater than 0, then all file storage paths within
 884          * the container are required to be hashed accordingly.
 885          *
 886          * @param $container string
 887          * @return Array (integer levels, integer base, repeat flag) or (0, 0, false)
 888          */
 889         final protected function getContainerHashLevels( $container ) {
 890                 if ( isset( $this->shardViaHashLevels[$container] ) ) {
 891                         $config = $this->shardViaHashLevels[$container];
 892                         $hashLevels = (int)$config['levels'];
 893                         if ( $hashLevels == 1 || $hashLevels == 2 ) {
 894                                 $hashBase = (int)$config['base'];
 895                                 if ( $hashBase == 16 || $hashBase == 36 ) {
 896                                         return array( $hashLevels, $hashBase, $config['repeat'] );
 897                                 }
 898                         }
 899                 }
 900                 return array( 0, 0, false ); // no sharding
 901         }
 902
 903         /**
 904          * Get a list of full container shard suffixes for a container
 905          *
 906          * @param $container string
 907          * @return Array
 908          */
 909         final protected function getContainerSuffixes( $container ) {
 910                 $shards = array();
 911                 list( $digits, $base ) = $this->getContainerHashLevels( $container );
 912                 if ( $digits > 0 ) {
 913                         $numShards = pow( $base, $digits );
 914                         for ( $index = 0; $index < $numShards; $index++ ) {
 915                                 $shards[] = '.' . wfBaseConvert( $index, 10, $base, $digits );
 916                         }
 917                 }
 918                 return $shards;
 919         }
 920
 921         /**
 922          * Get the full container name, including the wiki ID prefix
 923          *
 924          * @param $container string
 925          * @return string
 926          */
 927         final protected function fullContainerName( $container ) {
 928                 if ( $this->wikiId != '' ) {
 929                         return "{$this->wikiId}-$container";
 930                 } else {
 931                         return $container;
 932                 }
 933         }
 934
 935         /**
 936          * Resolve a container name, checking if it's allowed by the backend.
 937          * This is intended for internal use, such as encoding illegal chars.
 938          * Subclasses can override this to be more restrictive.
 939          *
 940          * @param $container string
 941          * @return string|null
 942          */
 943         protected function resolveContainerName( $container ) {
 944                 return $container;
 945         }
 946
 947         /**
 948          * Resolve a relative storage path, checking if it's allowed by the backend.
 949          * This is intended for internal use, such as encoding illegal chars or perhaps
 950          * getting absolute paths (e.g. FS based backends). Note that the relative path
 951          * may be the empty string (e.g. the path is simply to the container).
 952          *
 953          * @param $container string Container name
 954          * @param $relStoragePath string Storage path relative to the container
 955          * @return string|null Path or null if not valid
 956          */
 957         protected function resolveContainerPath( $container, $relStoragePath ) {
 958                 return $relStoragePath;
 959         }
 960 }
 961
 962 /**
 963  * FileBackendStore helper function to handle file listings that span container shards.
 964  * Do not use this class from places outside of FileBackendStore.
 965  *
 966  * @ingroup FileBackend
 967  */
 968 class FileBackendStoreShardListIterator implements Iterator {
 969         /* @var FileBackendStore */
 970         protected $backend;
 971         /* @var Array */
 972         protected $params;
 973         /* @var Array */
 974         protected $shardSuffixes;
 975         protected $container; // string
 976         protected $directory; // string
 977
 978         /* @var Traversable */
 979         protected $iter;
 980         protected $curShard = 0; // integer
 981         protected $pos = 0; // integer
 982
 983         /**
 984          * @param $backend FileBackendStore
 985          * @param $container string Full storage container name
 986          * @param $dir string Storage directory relative to container
 987          * @param $suffixes Array List of container shard suffixes
 988          * @param $params Array
 989          */
 990         public function __construct(
 991                 FileBackendStore $backend, $container, $dir, array $suffixes, array $params
 992         ) {
 993                 $this->backend = $backend;
 994                 $this->container = $container;
 995                 $this->directory = $dir;
 996                 $this->shardSuffixes = $suffixes;
 997                 $this->params = $params;
 998         }
 999
1000         /**
1001          * @see Iterator::current()
1002          * @return string|bool String or false
1003          */
1004         public function current() {
1005                 if ( is_array( $this->iter ) ) {
1006                         return current( $this->iter );
1007                 } else {
1008                         return $this->iter->current();
1009                 }
1010         }
1011
1012         /**
1013          * @see Iterator::key()
1014          * @return integer
1015          */
1016         public function key() {
1017                 return $this->pos;
1018         }
1019
1020         /**
1021          * @see Iterator::next()
1022          * @return void
1023          */
1024         public function next() {
1025                 ++$this->pos;
1026                 if ( is_array( $this->iter ) ) {
1027                         next( $this->iter );
1028                 } else {
1029                         $this->iter->next();
1030                 }
1031                 // Find the next non-empty shard if no elements are left
1032                 $this->nextShardIteratorIfNotValid();
1033         }
1034
1035         /**
1036          * @see Iterator::rewind()
1037          * @return void
1038          */
1039         public function rewind() {
1040                 $this->pos = 0;
1041                 $this->curShard = 0;
1042                 $this->setIteratorFromCurrentShard();
1043                 // Find the next non-empty shard if this one has no elements
1044                 $this->nextShardIteratorIfNotValid();
1045         }
1046
1047         /**
1048          * @see Iterator::valid()
1049          * @return bool
1050          */
1051         public function valid() {
1052                 if ( $this->iter == null ) {
1053                         return false; // some failure?
1054                 } elseif ( is_array( $this->iter ) ) {
1055                         return ( current( $this->iter ) !== false ); // no paths can have this value
1056                 } else {
1057                         return $this->iter->valid();
1058                 }
1059         }
1060
1061         /**
1062          * If the list iterator for this container shard is out of items,
1063          * then move on to the next container that has items.
1064          * If there are none, then it advances to the last container.
1065          */
1066         protected function nextShardIteratorIfNotValid() {
1067                 while ( !$this->valid() ) {
1068                         if ( ++$this->curShard >= count( $this->shardSuffixes ) ) {
1069                                 break; // no more container shards
1070                         }
1071                         $this->setIteratorFromCurrentShard();
1072                 }
1073         }
1074
1075         /**
1076          * Set the list iterator to that of the current container shard
1077          */
1078         protected function setIteratorFromCurrentShard() {
1079                 $suffix = $this->shardSuffixes[$this->curShard];
1080                 $this->iter = $this->backend->getFileListInternal(
1081                         "{$this->container}{$suffix}", $this->directory, $this->params );
1082         }
1083 }