includes/filerepo/backend/FileBackendStore.php

   1 <?php
   2 /**
   3  * Base class for all backends using particular storage medium.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  * @author Aaron Schulz
  23  */
  24
  25 /**
  26  * @brief Base class for all backends using particular storage medium.
  27  *
  28  * This class defines the methods as abstract that subclasses must implement.
  29  * Outside callers should *not* use functions with "Internal" in the name.
  30  *
  31  * The FileBackend operations are implemented using basic functions
  32  * such as storeInternal(), copyInternal(), deleteInternal() and the like.
  33  * This class is also responsible for path resolution and sanitization.
  34  *
  35  * @ingroup FileBackend
  36  * @since 1.19
  37  */
  38 abstract class FileBackendStore extends FileBackend {
  39         /** @var BagOStuff */
  40         protected $memCache;
  41
  42         /** @var Array Map of paths to small (RAM/disk) cache items */
  43         protected $cache = array(); // (storage path => key => value)
  44         protected $maxCacheSize = 300; // integer; max paths with entries
  45         /** @var Array Map of paths to large (RAM/disk) cache items */
  46         protected $expensiveCache = array(); // (storage path => key => value)
  47         protected $maxExpensiveCacheSize = 5; // integer; max paths with entries
  48
  49         /** @var Array Map of container names to sharding settings */
  50         protected $shardViaHashLevels = array(); // (container name => config array)
  51
  52         protected $maxFileSize = 4294967296; // integer bytes (4GiB)
  53
  54         /**
  55          * @see FileBackend::__construct()
  56          *
  57          * @param $config Array
  58          */
  59         public function __construct( array $config ) {
  60                 parent::__construct( $config );
  61                 $this->memCache = new EmptyBagOStuff(); // disabled by default
  62         }
  63
  64         /**
  65          * Get the maximum allowable file size given backend
  66          * medium restrictions and basic performance constraints.
  67          * Do not call this function from places outside FileBackend and FileOp.
  68          *
  69          * @return integer Bytes
  70          */
  71         final public function maxFileSizeInternal() {
  72                 return $this->maxFileSize;
  73         }
  74
  75         /**
  76          * Check if a file can be created at a given storage path.
  77          * FS backends should check if the parent directory exists and the file is writable.
  78          * Backends using key/value stores should check if the container exists.
  79          *
  80          * @param $storagePath string
  81          * @return bool
  82          */
  83         abstract public function isPathUsableInternal( $storagePath );
  84
  85         /**
  86          * Create a file in the backend with the given contents.
  87          * Do not call this function from places outside FileBackend and FileOp.
  88          *
  89          * $params include:
  90          *     content       : the raw file contents
  91          *     dst           : destination storage path
  92          *     overwrite     : overwrite any file that exists at the destination
  93          *     async         : Status will be returned immediately if supported.
  94          *                     If the status is OK, then its value field will be
  95          *                     set to a FileBackendStoreOpHandle object.
  96          *
  97          * @param $params Array
  98          * @return Status
  99          */
 100         final public function createInternal( array $params ) {
 101                 wfProfileIn( __METHOD__ );
 102                 wfProfileIn( __METHOD__ . '-' . $this->name );
 103                 if ( strlen( $params['content'] ) > $this->maxFileSizeInternal() ) {
 104                         $status = Status::newFatal( 'backend-fail-maxsize',
 105                                 $params['dst'], $this->maxFileSizeInternal() );
 106                 } else {
 107                         $status = $this->doCreateInternal( $params );
 108                         $this->clearCache( array( $params['dst'] ) );
 109                         $this->deleteFileCache( $params['dst'] ); // persistent cache
 110                 }
 111                 wfProfileOut( __METHOD__ . '-' . $this->name );
 112                 wfProfileOut( __METHOD__ );
 113                 return $status;
 114         }
 115
 116         /**
 117          * @see FileBackendStore::createInternal()
 118          */
 119         abstract protected function doCreateInternal( array $params );
 120
 121         /**
 122          * Store a file into the backend from a file on disk.
 123          * Do not call this function from places outside FileBackend and FileOp.
 124          *
 125          * $params include:
 126          *     src           : source path on disk
 127          *     dst           : destination storage path
 128          *     overwrite     : overwrite any file that exists at the destination
 129          *     async         : Status will be returned immediately if supported.
 130          *                     If the status is OK, then its value field will be
 131          *                     set to a FileBackendStoreOpHandle object.
 132          *
 133          * @param $params Array
 134          * @return Status
 135          */
 136         final public function storeInternal( array $params ) {
 137                 wfProfileIn( __METHOD__ );
 138                 wfProfileIn( __METHOD__ . '-' . $this->name );
 139                 if ( filesize( $params['src'] ) > $this->maxFileSizeInternal() ) {
 140                         $status = Status::newFatal( 'backend-fail-maxsize',
 141                                 $params['dst'], $this->maxFileSizeInternal() );
 142                 } else {
 143                         $status = $this->doStoreInternal( $params );
 144                         $this->clearCache( array( $params['dst'] ) );
 145                         $this->deleteFileCache( $params['dst'] ); // persistent cache
 146                 }
 147                 wfProfileOut( __METHOD__ . '-' . $this->name );
 148                 wfProfileOut( __METHOD__ );
 149                 return $status;
 150         }
 151
 152         /**
 153          * @see FileBackendStore::storeInternal()
 154          */
 155         abstract protected function doStoreInternal( array $params );
 156
 157         /**
 158          * Copy a file from one storage path to another in the backend.
 159          * Do not call this function from places outside FileBackend and FileOp.
 160          *
 161          * $params include:
 162          *     src           : source storage path
 163          *     dst           : destination storage path
 164          *     overwrite     : overwrite any file that exists at the destination
 165          *     async         : Status will be returned immediately if supported.
 166          *                     If the status is OK, then its value field will be
 167          *                     set to a FileBackendStoreOpHandle object.
 168          *
 169          * @param $params Array
 170          * @return Status
 171          */
 172         final public function copyInternal( array $params ) {
 173                 wfProfileIn( __METHOD__ );
 174                 wfProfileIn( __METHOD__ . '-' . $this->name );
 175                 $status = $this->doCopyInternal( $params );
 176                 $this->clearCache( array( $params['dst'] ) );
 177                 $this->deleteFileCache( $params['dst'] ); // persistent cache
 178                 wfProfileOut( __METHOD__ . '-' . $this->name );
 179                 wfProfileOut( __METHOD__ );
 180                 return $status;
 181         }
 182
 183         /**
 184          * @see FileBackendStore::copyInternal()
 185          */
 186         abstract protected function doCopyInternal( array $params );
 187
 188         /**
 189          * Delete a file at the storage path.
 190          * Do not call this function from places outside FileBackend and FileOp.
 191          *
 192          * $params include:
 193          *     src                 : source storage path
 194          *     ignoreMissingSource : do nothing if the source file does not exist
 195          *     async               : Status will be returned immediately if supported.
 196          *                           If the status is OK, then its value field will be
 197          *                           set to a FileBackendStoreOpHandle object.
 198          *
 199          * @param $params Array
 200          * @return Status
 201          */
 202         final public function deleteInternal( array $params ) {
 203                 wfProfileIn( __METHOD__ );
 204                 wfProfileIn( __METHOD__ . '-' . $this->name );
 205                 $status = $this->doDeleteInternal( $params );
 206                 $this->clearCache( array( $params['src'] ) );
 207                 $this->deleteFileCache( $params['src'] ); // persistent cache
 208                 wfProfileOut( __METHOD__ . '-' . $this->name );
 209                 wfProfileOut( __METHOD__ );
 210                 return $status;
 211         }
 212
 213         /**
 214          * @see FileBackendStore::deleteInternal()
 215          */
 216         abstract protected function doDeleteInternal( array $params );
 217
 218         /**
 219          * Move a file from one storage path to another in the backend.
 220          * Do not call this function from places outside FileBackend and FileOp.
 221          *
 222          * $params include:
 223          *     src           : source storage path
 224          *     dst           : destination storage path
 225          *     overwrite     : overwrite any file that exists at the destination
 226          *     async         : Status will be returned immediately if supported.
 227          *                     If the status is OK, then its value field will be
 228          *                     set to a FileBackendStoreOpHandle object.
 229          *
 230          * @param $params Array
 231          * @return Status
 232          */
 233         final public function moveInternal( array $params ) {
 234                 wfProfileIn( __METHOD__ );
 235                 wfProfileIn( __METHOD__ . '-' . $this->name );
 236                 $status = $this->doMoveInternal( $params );
 237                 $this->clearCache( array( $params['src'], $params['dst'] ) );
 238                 $this->deleteFileCache( $params['src'] ); // persistent cache
 239                 $this->deleteFileCache( $params['dst'] ); // persistent cache
 240                 wfProfileOut( __METHOD__ . '-' . $this->name );
 241                 wfProfileOut( __METHOD__ );
 242                 return $status;
 243         }
 244
 245         /**
 246          * @see FileBackendStore::moveInternal()
 247          * @return Status
 248          */
 249         protected function doMoveInternal( array $params ) {
 250                 unset( $params['async'] ); // two steps, won't work here :)
 251                 // Copy source to dest
 252                 $status = $this->copyInternal( $params );
 253                 if ( $status->isOK() ) {
 254                         // Delete source (only fails due to races or medium going down)
 255                         $status->merge( $this->deleteInternal( array( 'src' => $params['src'] ) ) );
 256                         $status->setResult( true, $status->value ); // ignore delete() errors
 257                 }
 258                 return $status;
 259         }
 260
 261         /**
 262          * No-op file operation that does nothing.
 263          * Do not call this function from places outside FileBackend and FileOp.
 264          *
 265          * @param $params Array
 266          * @return Status
 267          */
 268         final public function nullInternal( array $params ) {
 269                 return Status::newGood();
 270         }
 271
 272         /**
 273          * @see FileBackend::concatenate()
 274          * @return Status
 275          */
 276         final public function concatenate( array $params ) {
 277                 wfProfileIn( __METHOD__ );
 278                 wfProfileIn( __METHOD__ . '-' . $this->name );
 279                 $status = Status::newGood();
 280
 281                 // Try to lock the source files for the scope of this function
 282                 $scopeLockS = $this->getScopedFileLocks( $params['srcs'], LockManager::LOCK_UW, $status );
 283                 if ( $status->isOK() ) {
 284                         // Actually do the concatenation
 285                         $status->merge( $this->doConcatenate( $params ) );
 286                 }
 287
 288                 wfProfileOut( __METHOD__ . '-' . $this->name );
 289                 wfProfileOut( __METHOD__ );
 290                 return $status;
 291         }
 292
 293         /**
 294          * @see FileBackendStore::concatenate()
 295          * @return Status
 296          */
 297         protected function doConcatenate( array $params ) {
 298                 $status = Status::newGood();
 299                 $tmpPath = $params['dst']; // convenience
 300
 301                 // Check that the specified temp file is valid...
 302                 wfSuppressWarnings();
 303                 $ok = ( is_file( $tmpPath ) && !filesize( $tmpPath ) );
 304                 wfRestoreWarnings();
 305                 if ( !$ok ) { // not present or not empty
 306                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 307                         return $status;
 308                 }
 309
 310                 // Build up the temp file using the source chunks (in order)...
 311                 $tmpHandle = fopen( $tmpPath, 'ab' );
 312                 if ( $tmpHandle === false ) {
 313                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 314                         return $status;
 315                 }
 316                 foreach ( $params['srcs'] as $virtualSource ) {
 317                         // Get a local FS version of the chunk
 318                         $tmpFile = $this->getLocalReference( array( 'src' => $virtualSource ) );
 319                         if ( !$tmpFile ) {
 320                                 $status->fatal( 'backend-fail-read', $virtualSource );
 321                                 return $status;
 322                         }
 323                         // Get a handle to the local FS version
 324                         $sourceHandle = fopen( $tmpFile->getPath(), 'r' );
 325                         if ( $sourceHandle === false ) {
 326                                 fclose( $tmpHandle );
 327                                 $status->fatal( 'backend-fail-read', $virtualSource );
 328                                 return $status;
 329                         }
 330                         // Append chunk to file (pass chunk size to avoid magic quotes)
 331                         if ( !stream_copy_to_stream( $sourceHandle, $tmpHandle ) ) {
 332                                 fclose( $sourceHandle );
 333                                 fclose( $tmpHandle );
 334                                 $status->fatal( 'backend-fail-writetemp', $tmpPath );
 335                                 return $status;
 336                         }
 337                         fclose( $sourceHandle );
 338                 }
 339                 if ( !fclose( $tmpHandle ) ) {
 340                         $status->fatal( 'backend-fail-closetemp', $tmpPath );
 341                         return $status;
 342                 }
 343
 344                 clearstatcache(); // temp file changed
 345
 346                 return $status;
 347         }
 348
 349         /**
 350          * @see FileBackend::doPrepare()
 351          * @return Status
 352          */
 353         final protected function doPrepare( array $params ) {
 354                 wfProfileIn( __METHOD__ );
 355                 wfProfileIn( __METHOD__ . '-' . $this->name );
 356
 357                 $status = Status::newGood();
 358                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 359                 if ( $dir === null ) {
 360                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 361                         wfProfileOut( __METHOD__ . '-' . $this->name );
 362                         wfProfileOut( __METHOD__ );
 363                         return $status; // invalid storage path
 364                 }
 365
 366                 if ( $shard !== null ) { // confined to a single container/shard
 367                         $status->merge( $this->doPrepareInternal( $fullCont, $dir, $params ) );
 368                 } else { // directory is on several shards
 369                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 370                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 371                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 372                                 $status->merge( $this->doPrepareInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 373                         }
 374                 }
 375
 376                 wfProfileOut( __METHOD__ . '-' . $this->name );
 377                 wfProfileOut( __METHOD__ );
 378                 return $status;
 379         }
 380
 381         /**
 382          * @see FileBackendStore::doPrepare()
 383          * @return Status
 384          */
 385         protected function doPrepareInternal( $container, $dir, array $params ) {
 386                 return Status::newGood();
 387         }
 388
 389         /**
 390          * @see FileBackend::doSecure()
 391          * @return Status
 392          */
 393         final protected function doSecure( array $params ) {
 394                 wfProfileIn( __METHOD__ );
 395                 wfProfileIn( __METHOD__ . '-' . $this->name );
 396                 $status = Status::newGood();
 397
 398                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 399                 if ( $dir === null ) {
 400                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 401                         wfProfileOut( __METHOD__ . '-' . $this->name );
 402                         wfProfileOut( __METHOD__ );
 403                         return $status; // invalid storage path
 404                 }
 405
 406                 if ( $shard !== null ) { // confined to a single container/shard
 407                         $status->merge( $this->doSecureInternal( $fullCont, $dir, $params ) );
 408                 } else { // directory is on several shards
 409                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 410                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 411                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 412                                 $status->merge( $this->doSecureInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 413                         }
 414                 }
 415
 416                 wfProfileOut( __METHOD__ . '-' . $this->name );
 417                 wfProfileOut( __METHOD__ );
 418                 return $status;
 419         }
 420
 421         /**
 422          * @see FileBackendStore::doSecure()
 423          * @return Status
 424          */
 425         protected function doSecureInternal( $container, $dir, array $params ) {
 426                 return Status::newGood();
 427         }
 428
 429         /**
 430          * @see FileBackend::doClean()
 431          * @return Status
 432          */
 433         final protected function doClean( array $params ) {
 434                 wfProfileIn( __METHOD__ );
 435                 wfProfileIn( __METHOD__ . '-' . $this->name );
 436                 $status = Status::newGood();
 437
 438                 // Recursive: first delete all empty subdirs recursively
 439                 if ( !empty( $params['recursive'] ) && !$this->directoriesAreVirtual() ) {
 440                         $subDirsRel = $this->getTopDirectoryList( array( 'dir' => $params['dir'] ) );
 441                         if ( $subDirsRel !== null ) { // no errors
 442                                 foreach ( $subDirsRel as $subDirRel ) {
 443                                         $subDir = $params['dir'] . "/{$subDirRel}"; // full path
 444                                         $status->merge( $this->doClean( array( 'dir' => $subDir ) + $params ) );
 445                                 }
 446                         }
 447                 }
 448
 449                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 450                 if ( $dir === null ) {
 451                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 452                         wfProfileOut( __METHOD__ . '-' . $this->name );
 453                         wfProfileOut( __METHOD__ );
 454                         return $status; // invalid storage path
 455                 }
 456
 457                 // Attempt to lock this directory...
 458                 $filesLockEx = array( $params['dir'] );
 459                 $scopedLockE = $this->getScopedFileLocks( $filesLockEx, LockManager::LOCK_EX, $status );
 460                 if ( !$status->isOK() ) {
 461                         wfProfileOut( __METHOD__ . '-' . $this->name );
 462                         wfProfileOut( __METHOD__ );
 463                         return $status; // abort
 464                 }
 465
 466                 if ( $shard !== null ) { // confined to a single container/shard
 467                         $status->merge( $this->doCleanInternal( $fullCont, $dir, $params ) );
 468                         $this->deleteContainerCache( $fullCont ); // purge cache
 469                 } else { // directory is on several shards
 470                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 471                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 472                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 473                                 $status->merge( $this->doCleanInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 474                                 $this->deleteContainerCache( "{$fullCont}{$suffix}" ); // purge cache
 475                         }
 476                 }
 477
 478                 wfProfileOut( __METHOD__ . '-' . $this->name );
 479                 wfProfileOut( __METHOD__ );
 480                 return $status;
 481         }
 482
 483         /**
 484          * @see FileBackendStore::doClean()
 485          * @return Status
 486          */
 487         protected function doCleanInternal( $container, $dir, array $params ) {
 488                 return Status::newGood();
 489         }
 490
 491         /**
 492          * @see FileBackend::fileExists()
 493          * @return bool|null
 494          */
 495         final public function fileExists( array $params ) {
 496                 wfProfileIn( __METHOD__ );
 497                 wfProfileIn( __METHOD__ . '-' . $this->name );
 498                 $stat = $this->getFileStat( $params );
 499                 wfProfileOut( __METHOD__ . '-' . $this->name );
 500                 wfProfileOut( __METHOD__ );
 501                 return ( $stat === null ) ? null : (bool)$stat; // null => failure
 502         }
 503
 504         /**
 505          * @see FileBackend::getFileTimestamp()
 506          * @return bool
 507          */
 508         final public function getFileTimestamp( array $params ) {
 509                 wfProfileIn( __METHOD__ );
 510                 wfProfileIn( __METHOD__ . '-' . $this->name );
 511                 $stat = $this->getFileStat( $params );
 512                 wfProfileOut( __METHOD__ . '-' . $this->name );
 513                 wfProfileOut( __METHOD__ );
 514                 return $stat ? $stat['mtime'] : false;
 515         }
 516
 517         /**
 518          * @see FileBackend::getFileSize()
 519          * @return bool
 520          */
 521         final public function getFileSize( array $params ) {
 522                 wfProfileIn( __METHOD__ );
 523                 wfProfileIn( __METHOD__ . '-' . $this->name );
 524                 $stat = $this->getFileStat( $params );
 525                 wfProfileOut( __METHOD__ . '-' . $this->name );
 526                 wfProfileOut( __METHOD__ );
 527                 return $stat ? $stat['size'] : false;
 528         }
 529
 530         /**
 531          * @see FileBackend::getFileStat()
 532          * @return bool
 533          */
 534         final public function getFileStat( array $params ) {
 535                 wfProfileIn( __METHOD__ );
 536                 wfProfileIn( __METHOD__ . '-' . $this->name );
 537                 $path = self::normalizeStoragePath( $params['src'] );
 538                 if ( $path === null ) {
 539                         wfProfileOut( __METHOD__ . '-' . $this->name );
 540                         wfProfileOut( __METHOD__ );
 541                         return false; // invalid storage path
 542                 }
 543                 $latest = !empty( $params['latest'] ); // use latest data?
 544                 if ( !isset( $this->cache[$path]['stat'] ) ) {
 545                         $this->primeFileCache( array( $path ) ); // check persistent cache
 546                 }
 547                 if ( isset( $this->cache[$path]['stat'] ) ) {
 548                         // If we want the latest data, check that this cached
 549                         // value was in fact fetched with the latest available data.
 550                         if ( !$latest || $this->cache[$path]['stat']['latest'] ) {
 551                                 $this->pingCache( $path ); // LRU
 552                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 553                                 wfProfileOut( __METHOD__ );
 554                                 return $this->cache[$path]['stat'];
 555                         }
 556                 }
 557                 wfProfileIn( __METHOD__ . '-miss' );
 558                 wfProfileIn( __METHOD__ . '-miss-' . $this->name );
 559                 $stat = $this->doGetFileStat( $params );
 560                 wfProfileOut( __METHOD__ . '-miss-' . $this->name );
 561                 wfProfileOut( __METHOD__ . '-miss' );
 562                 if ( is_array( $stat ) ) { // don't cache negatives
 563                         $stat['latest'] = $latest;
 564                         $this->trimCache(); // limit memory
 565                         $this->cache[$path]['stat'] = $stat;
 566                         $this->setFileCache( $path, $stat ); // update persistent cache
 567                 }
 568                 wfProfileOut( __METHOD__ . '-' . $this->name );
 569                 wfProfileOut( __METHOD__ );
 570                 return $stat;
 571         }
 572
 573         /**
 574          * @see FileBackendStore::getFileStat()
 575          */
 576         abstract protected function doGetFileStat( array $params );
 577
 578         /**
 579          * @see FileBackend::getFileContents()
 580          * @return bool|string
 581          */
 582         public function getFileContents( array $params ) {
 583                 wfProfileIn( __METHOD__ );
 584                 wfProfileIn( __METHOD__ . '-' . $this->name );
 585                 $tmpFile = $this->getLocalReference( $params );
 586                 if ( !$tmpFile ) {
 587                         wfProfileOut( __METHOD__ . '-' . $this->name );
 588                         wfProfileOut( __METHOD__ );
 589                         return false;
 590                 }
 591                 wfSuppressWarnings();
 592                 $data = file_get_contents( $tmpFile->getPath() );
 593                 wfRestoreWarnings();
 594                 wfProfileOut( __METHOD__ . '-' . $this->name );
 595                 wfProfileOut( __METHOD__ );
 596                 return $data;
 597         }
 598
 599         /**
 600          * @see FileBackend::getFileSha1Base36()
 601          * @return bool|string
 602          */
 603         final public function getFileSha1Base36( array $params ) {
 604                 wfProfileIn( __METHOD__ );
 605                 wfProfileIn( __METHOD__ . '-' . $this->name );
 606                 $path = $params['src'];
 607                 if ( isset( $this->cache[$path]['sha1'] ) ) {
 608                         $this->pingCache( $path ); // LRU
 609                         wfProfileOut( __METHOD__ . '-' . $this->name );
 610                         wfProfileOut( __METHOD__ );
 611                         return $this->cache[$path]['sha1'];
 612                 }
 613                 wfProfileIn( __METHOD__ . '-miss' );
 614                 wfProfileIn( __METHOD__ . '-miss-' . $this->name );
 615                 $hash = $this->doGetFileSha1Base36( $params );
 616                 wfProfileOut( __METHOD__ . '-miss-' . $this->name );
 617                 wfProfileOut( __METHOD__ . '-miss' );
 618                 if ( $hash ) { // don't cache negatives
 619                         $this->trimCache(); // limit memory
 620                         $this->cache[$path]['sha1'] = $hash;
 621                 }
 622                 wfProfileOut( __METHOD__ . '-' . $this->name );
 623                 wfProfileOut( __METHOD__ );
 624                 return $hash;
 625         }
 626
 627         /**
 628          * @see FileBackendStore::getFileSha1Base36()
 629          * @return bool
 630          */
 631         protected function doGetFileSha1Base36( array $params ) {
 632                 $fsFile = $this->getLocalReference( $params );
 633                 if ( !$fsFile ) {
 634                         return false;
 635                 } else {
 636                         return $fsFile->getSha1Base36();
 637                 }
 638         }
 639
 640         /**
 641          * @see FileBackend::getFileProps()
 642          * @return Array
 643          */
 644         final public function getFileProps( array $params ) {
 645                 wfProfileIn( __METHOD__ );
 646                 wfProfileIn( __METHOD__ . '-' . $this->name );
 647                 $fsFile = $this->getLocalReference( $params );
 648                 $props = $fsFile ? $fsFile->getProps() : FSFile::placeholderProps();
 649                 wfProfileOut( __METHOD__ . '-' . $this->name );
 650                 wfProfileOut( __METHOD__ );
 651                 return $props;
 652         }
 653
 654         /**
 655          * @see FileBackend::getLocalReference()
 656          * @return TempFSFile|null
 657          */
 658         public function getLocalReference( array $params ) {
 659                 wfProfileIn( __METHOD__ );
 660                 wfProfileIn( __METHOD__ . '-' . $this->name );
 661                 $path = $params['src'];
 662                 if ( isset( $this->expensiveCache[$path]['localRef'] ) ) {
 663                         $this->pingExpensiveCache( $path );
 664                         wfProfileOut( __METHOD__ . '-' . $this->name );
 665                         wfProfileOut( __METHOD__ );
 666                         return $this->expensiveCache[$path]['localRef'];
 667                 }
 668                 $tmpFile = $this->getLocalCopy( $params );
 669                 if ( $tmpFile ) { // don't cache negatives
 670                         $this->trimExpensiveCache(); // limit memory
 671                         $this->expensiveCache[$path]['localRef'] = $tmpFile;
 672                 }
 673                 wfProfileOut( __METHOD__ . '-' . $this->name );
 674                 wfProfileOut( __METHOD__ );
 675                 return $tmpFile;
 676         }
 677
 678         /**
 679          * @see FileBackend::streamFile()
 680          * @return Status
 681          */
 682         final public function streamFile( array $params ) {
 683                 wfProfileIn( __METHOD__ );
 684                 wfProfileIn( __METHOD__ . '-' . $this->name );
 685                 $status = Status::newGood();
 686
 687                 $info = $this->getFileStat( $params );
 688                 if ( !$info ) { // let StreamFile handle the 404
 689                         $status->fatal( 'backend-fail-notexists', $params['src'] );
 690                 }
 691
 692                 // Set output buffer and HTTP headers for stream
 693                 $extraHeaders = isset( $params['headers'] ) ? $params['headers'] : array();
 694                 $res = StreamFile::prepareForStream( $params['src'], $info, $extraHeaders );
 695                 if ( $res == StreamFile::NOT_MODIFIED ) {
 696                         // do nothing; client cache is up to date
 697                 } elseif ( $res == StreamFile::READY_STREAM ) {
 698                         wfProfileIn( __METHOD__ . '-send' );
 699                         wfProfileIn( __METHOD__ . '-send-' . $this->name );
 700                         $status = $this->doStreamFile( $params );
 701                         wfProfileOut( __METHOD__ . '-send-' . $this->name );
 702                         wfProfileOut( __METHOD__ . '-send' );
 703                 } else {
 704                         $status->fatal( 'backend-fail-stream', $params['src'] );
 705                 }
 706
 707                 wfProfileOut( __METHOD__ . '-' . $this->name );
 708                 wfProfileOut( __METHOD__ );
 709                 return $status;
 710         }
 711
 712         /**
 713          * @see FileBackendStore::streamFile()
 714          * @return Status
 715          */
 716         protected function doStreamFile( array $params ) {
 717                 $status = Status::newGood();
 718
 719                 $fsFile = $this->getLocalReference( $params );
 720                 if ( !$fsFile ) {
 721                         $status->fatal( 'backend-fail-stream', $params['src'] );
 722                 } elseif ( !readfile( $fsFile->getPath() ) ) {
 723                         $status->fatal( 'backend-fail-stream', $params['src'] );
 724                 }
 725
 726                 return $status;
 727         }
 728
 729         /**
 730          * @see FileBackend::directoryExists()
 731          * @return bool|null
 732          */
 733         final public function directoryExists( array $params ) {
 734                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 735                 if ( $dir === null ) {
 736                         return false; // invalid storage path
 737                 }
 738                 if ( $shard !== null ) { // confined to a single container/shard
 739                         return $this->doDirectoryExists( $fullCont, $dir, $params );
 740                 } else { // directory is on several shards
 741                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 742                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 743                         $res = false; // response
 744                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 745                                 $exists = $this->doDirectoryExists( "{$fullCont}{$suffix}", $dir, $params );
 746                                 if ( $exists ) {
 747                                         $res = true;
 748                                         break; // found one!
 749                                 } elseif ( $exists === null ) { // error?
 750                                         $res = null; // if we don't find anything, it is indeterminate
 751                                 }
 752                         }
 753                         return $res;
 754                 }
 755         }
 756
 757         /**
 758          * @see FileBackendStore::directoryExists()
 759          *
 760          * @param $container string Resolved container name
 761          * @param $dir string Resolved path relative to container
 762          * @param $params Array
 763          * @return bool|null
 764          */
 765         abstract protected function doDirectoryExists( $container, $dir, array $params );
 766
 767         /**
 768          * @see FileBackend::getDirectoryList()
 769          * @return Traversable|Array|null Returns null on failure
 770          */
 771         final public function getDirectoryList( array $params ) {
 772                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 773                 if ( $dir === null ) { // invalid storage path
 774                         return null;
 775                 }
 776                 if ( $shard !== null ) {
 777                         // File listing is confined to a single container/shard
 778                         return $this->getDirectoryListInternal( $fullCont, $dir, $params );
 779                 } else {
 780                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 781                         // File listing spans multiple containers/shards
 782                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 783                         return new FileBackendStoreShardDirIterator( $this,
 784                                 $fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
 785                 }
 786         }
 787
 788         /**
 789          * Do not call this function from places outside FileBackend
 790          *
 791          * @see FileBackendStore::getDirectoryList()
 792          *
 793          * @param $container string Resolved container name
 794          * @param $dir string Resolved path relative to container
 795          * @param $params Array
 796          * @return Traversable|Array|null Returns null on failure
 797          */
 798         abstract public function getDirectoryListInternal( $container, $dir, array $params );
 799
 800         /**
 801          * @see FileBackend::getFileList()
 802          * @return Traversable|Array|null Returns null on failure
 803          */
 804         final public function getFileList( array $params ) {
 805                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 806                 if ( $dir === null ) { // invalid storage path
 807                         return null;
 808                 }
 809                 if ( $shard !== null ) {
 810                         // File listing is confined to a single container/shard
 811                         return $this->getFileListInternal( $fullCont, $dir, $params );
 812                 } else {
 813                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 814                         // File listing spans multiple containers/shards
 815                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 816                         return new FileBackendStoreShardFileIterator( $this,
 817                                 $fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
 818                 }
 819         }
 820
 821         /**
 822          * Do not call this function from places outside FileBackend
 823          *
 824          * @see FileBackendStore::getFileList()
 825          *
 826          * @param $container string Resolved container name
 827          * @param $dir string Resolved path relative to container
 828          * @param $params Array
 829          * @return Traversable|Array|null Returns null on failure
 830          */
 831         abstract public function getFileListInternal( $container, $dir, array $params );
 832
 833         /**
 834          * Return a list of FileOp objects from a list of operations.
 835          * Do not call this function from places outside FileBackend.
 836          *
 837          * The result must have the same number of items as the input.
 838          * An exception is thrown if an unsupported operation is requested.
 839          *
 840          * @param $ops Array Same format as doOperations()
 841          * @return Array List of FileOp objects
 842          * @throws MWException
 843          */
 844         final public function getOperationsInternal( array $ops ) {
 845                 $supportedOps = array(
 846                         'store'       => 'StoreFileOp',
 847                         'copy'        => 'CopyFileOp',
 848                         'move'        => 'MoveFileOp',
 849                         'delete'      => 'DeleteFileOp',
 850                         'create'      => 'CreateFileOp',
 851                         'null'        => 'NullFileOp'
 852                 );
 853
 854                 $performOps = array(); // array of FileOp objects
 855                 // Build up ordered array of FileOps...
 856                 foreach ( $ops as $operation ) {
 857                         $opName = $operation['op'];
 858                         if ( isset( $supportedOps[$opName] ) ) {
 859                                 $class = $supportedOps[$opName];
 860                                 // Get params for this operation
 861                                 $params = $operation;
 862                                 // Append the FileOp class
 863                                 $performOps[] = new $class( $this, $params );
 864                         } else {
 865                                 throw new MWException( "Operation '$opName' is not supported." );
 866                         }
 867                 }
 868
 869                 return $performOps;
 870         }
 871
 872         /**
 873          * Get a list of storage paths to lock for a list of operations
 874          * Returns an array with 'sh' (shared) and 'ex' (exclusive) keys,
 875          * each corresponding to a list of storage paths to be locked.
 876          *
 877          * @param $performOps Array List of FileOp objects
 878          * @return Array ('sh' => list of paths, 'ex' => list of paths)
 879          */
 880         final public function getPathsToLockForOpsInternal( array $performOps ) {
 881                 // Build up a list of files to lock...
 882                 $paths = array( 'sh' => array(), 'ex' => array() );
 883                 foreach ( $performOps as $fileOp ) {
 884                         $paths['sh'] = array_merge( $paths['sh'], $fileOp->storagePathsRead() );
 885                         $paths['ex'] = array_merge( $paths['ex'], $fileOp->storagePathsChanged() );
 886                 }
 887                 // Optimization: if doing an EX lock anyway, don't also set an SH one
 888                 $paths['sh'] = array_diff( $paths['sh'], $paths['ex'] );
 889                 // Get a shared lock on the parent directory of each path changed
 890                 $paths['sh'] = array_merge( $paths['sh'], array_map( 'dirname', $paths['ex'] ) );
 891
 892                 return $paths;
 893         }
 894
 895         /**
 896          * @see FileBackend::doOperationsInternal()
 897          * @return Status
 898          */
 899         protected function doOperationsInternal( array $ops, array $opts ) {
 900                 wfProfileIn( __METHOD__ );
 901                 wfProfileIn( __METHOD__ . '-' . $this->name );
 902                 $status = Status::newGood();
 903
 904                 // Build up a list of FileOps...
 905                 $performOps = $this->getOperationsInternal( $ops );
 906
 907                 // Acquire any locks as needed...
 908                 if ( empty( $opts['nonLocking'] ) ) {
 909                         // Build up a list of files to lock...
 910                         $paths = $this->getPathsToLockForOpsInternal( $performOps );
 911                         // Try to lock those files for the scope of this function...
 912                         $scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status );
 913                         $scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status );
 914                         if ( !$status->isOK() ) {
 915                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 916                                 wfProfileOut( __METHOD__ );
 917                                 return $status; // abort
 918                         }
 919                 }
 920
 921                 // Clear any file cache entries (after locks acquired)
 922                 $this->clearCache();
 923
 924                 // Load from the persistent file and container caches
 925                 $this->primeFileCache( $performOps );
 926                 $this->primeContainerCache( $performOps );
 927
 928                 // Actually attempt the operation batch...
 929                 $subStatus = FileOpBatch::attempt( $performOps, $opts, $this->fileJournal );
 930
 931                 // Merge errors into status fields
 932                 $status->merge( $subStatus );
 933                 $status->success = $subStatus->success; // not done in merge()
 934
 935                 wfProfileOut( __METHOD__ . '-' . $this->name );
 936                 wfProfileOut( __METHOD__ );
 937                 return $status;
 938         }
 939
 940         /**
 941          * @see FileBackend::doQuickOperationsInternal()
 942          * @return Status
 943          * @throws MWException
 944          */
 945         final protected function doQuickOperationsInternal( array $ops ) {
 946                 $status = Status::newGood();
 947
 948                 $async = ( $this->parallelize === 'implicit' );
 949                 $maxConcurrency = $this->concurrency; // throttle
 950
 951                 $statuses = array(); // array of (index => Status)
 952                 $fileOpHandles = array(); // list of (index => handle) arrays
 953                 $curFileOpHandles = array(); // current handle batch
 954                 // Perform the sync-only ops and build up op handles for the async ops...
 955                 foreach ( $ops as $index => $params ) {
 956                         $method = $params['op'] . 'Internal'; // e.g. "storeInternal"
 957                         if ( !MWInit::methodExists( __CLASS__, $method ) ) {
 958                                 throw new MWException( "Operation '{$params['op']}' is not supported." );
 959                         }
 960                         $subStatus = $this->$method( array( 'async' => $async ) + $params );
 961                         if ( $subStatus->value instanceof FileBackendStoreOpHandle ) { // async
 962                                 if ( count( $curFileOpHandles ) >= $maxConcurrency ) {
 963                                         $fileOpHandles[] = $curFileOpHandles; // push this batch
 964                                         $curFileOpHandles = array();
 965                                 }
 966                                 $curFileOpHandles[$index] = $subStatus->value; // keep index
 967                         } else { // error or completed
 968                                 $statuses[$index] = $subStatus; // keep index
 969                         }
 970                 }
 971                 if ( count( $curFileOpHandles ) ) {
 972                         $fileOpHandles[] = $curFileOpHandles; // last batch
 973                 }
 974                 // Do all the async ops that can be done concurrently...
 975                 foreach ( $fileOpHandles as $fileHandleBatch ) {
 976                         $statuses = $statuses + $this->executeOpHandlesInternal( $fileHandleBatch );
 977                 }
 978                 // Marshall and merge all the responses...
 979                 foreach ( $statuses as $index => $subStatus ) {
 980                         $status->merge( $subStatus );
 981                         if ( $subStatus->isOK() ) {
 982                                 $status->success[$index] = true;
 983                                 ++$status->successCount;
 984                         } else {
 985                                 $status->success[$index] = false;
 986                                 ++$status->failCount;
 987                         }
 988                 }
 989
 990                 return $status;
 991         }
 992
 993         /**
 994          * Execute a list of FileBackendStoreOpHandle handles in parallel.
 995          * The resulting Status object fields will correspond
 996          * to the order in which the handles where given.
 997          *
 998          * @param $handles Array List of FileBackendStoreOpHandle objects
 999          * @return Array Map of Status objects
1000          * @throws MWException
1001          */
1002         final public function executeOpHandlesInternal( array $fileOpHandles ) {
1003                 wfProfileIn( __METHOD__ );
1004                 wfProfileIn( __METHOD__ . '-' . $this->name );
1005                 foreach ( $fileOpHandles as $fileOpHandle ) {
1006                         if ( !( $fileOpHandle instanceof FileBackendStoreOpHandle ) ) {
1007                                 throw new MWException( "Given a non-FileBackendStoreOpHandle object." );
1008                         } elseif ( $fileOpHandle->backend->getName() !== $this->getName() ) {
1009                                 throw new MWException( "Given a FileBackendStoreOpHandle for the wrong backend." );
1010                         }
1011                 }
1012                 $res = $this->doExecuteOpHandlesInternal( $fileOpHandles );
1013                 wfProfileOut( __METHOD__ . '-' . $this->name );
1014                 wfProfileOut( __METHOD__ );
1015                 return $res;
1016         }
1017
1018         /**
1019          * @see FileBackendStore::executeOpHandlesInternal()
1020          * @return Array List of corresponding Status objects
1021          * @throws MWException
1022          */
1023         protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
1024                 foreach ( $fileOpHandles as $fileOpHandle ) { // OK if empty
1025                         throw new MWException( "This backend supports no asynchronous operations." );
1026                 }
1027                 return array();
1028         }
1029
1030         /**
1031          * @see FileBackend::clearCache()
1032          */
1033         final public function clearCache( array $paths = null ) {
1034                 if ( is_array( $paths ) ) {
1035                         $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1036                         $paths = array_filter( $paths, 'strlen' ); // remove nulls
1037                 }
1038                 if ( $paths === null ) {
1039                         $this->cache = array();
1040                         $this->expensiveCache = array();
1041                 } else {
1042                         foreach ( $paths as $path ) {
1043                                 unset( $this->cache[$path] );
1044                                 unset( $this->expensiveCache[$path] );
1045                         }
1046                 }
1047                 $this->doClearCache( $paths );
1048         }
1049
1050         /**
1051          * Clears any additional stat caches for storage paths
1052          *
1053          * @see FileBackend::clearCache()
1054          *
1055          * @param $paths Array Storage paths (optional)
1056          * @return void
1057          */
1058         protected function doClearCache( array $paths = null ) {}
1059
1060         /**
1061          * Is this a key/value store where directories are just virtual?
1062          * Virtual directories exists in so much as files exists that are
1063          * prefixed with the directory path followed by a forward slash.
1064          *
1065          * @return bool
1066          */
1067         abstract protected function directoriesAreVirtual();
1068
1069         /**
1070          * Move a cache entry to the top (such as when accessed)
1071          *
1072          * @param $path string Storage path
1073          * @return void
1074          */
1075         protected function pingCache( $path ) {
1076                 if ( isset( $this->cache[$path] ) ) {
1077                         $tmp = $this->cache[$path];
1078                         unset( $this->cache[$path] );
1079                         $this->cache[$path] = $tmp;
1080                 }
1081         }
1082
1083         /**
1084          * Prune the inexpensive cache if it is too big to add an item
1085          *
1086          * @return void
1087          */
1088         protected function trimCache() {
1089                 if ( count( $this->cache ) >= $this->maxCacheSize ) {
1090                         reset( $this->cache );
1091                         unset( $this->cache[key( $this->cache )] );
1092                 }
1093         }
1094
1095         /**
1096          * Move a cache entry to the top (such as when accessed)
1097          *
1098          * @param $path string Storage path
1099          * @return void
1100          */
1101         protected function pingExpensiveCache( $path ) {
1102                 if ( isset( $this->expensiveCache[$path] ) ) {
1103                         $tmp = $this->expensiveCache[$path];
1104                         unset( $this->expensiveCache[$path] );
1105                         $this->expensiveCache[$path] = $tmp;
1106                 }
1107         }
1108
1109         /**
1110          * Prune the expensive cache if it is too big to add an item
1111          *
1112          * @return void
1113          */
1114         protected function trimExpensiveCache() {
1115                 if ( count( $this->expensiveCache ) >= $this->maxExpensiveCacheSize ) {
1116                         reset( $this->expensiveCache );
1117                         unset( $this->expensiveCache[key( $this->expensiveCache )] );
1118                 }
1119         }
1120
1121         /**
1122          * Check if a container name is valid.
1123          * This checks for for length and illegal characters.
1124          *
1125          * @param $container string
1126          * @return bool
1127          */
1128         final protected static function isValidContainerName( $container ) {
1129                 // This accounts for Swift and S3 restrictions while leaving room
1130                 // for things like '.xxx' (hex shard chars) or '.seg' (segments).
1131                 // This disallows directory separators or traversal characters.
1132                 // Note that matching strings URL encode to the same string;
1133                 // in Swift, the length restriction is *after* URL encoding.
1134                 return preg_match( '/^[a-z0-9][a-z0-9-_]{0,199}$/i', $container );
1135         }
1136
1137         /**
1138          * Splits a storage path into an internal container name,
1139          * an internal relative file name, and a container shard suffix.
1140          * Any shard suffix is already appended to the internal container name.
1141          * This also checks that the storage path is valid and within this backend.
1142          *
1143          * If the container is sharded but a suffix could not be determined,
1144          * this means that the path can only refer to a directory and can only
1145          * be scanned by looking in all the container shards.
1146          *
1147          * @param $storagePath string
1148          * @return Array (container, path, container suffix) or (null, null, null) if invalid
1149          */
1150         final protected function resolveStoragePath( $storagePath ) {
1151                 list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
1152                 if ( $backend === $this->name ) { // must be for this backend
1153                         $relPath = self::normalizeContainerPath( $relPath );
1154                         if ( $relPath !== null ) {
1155                                 // Get shard for the normalized path if this container is sharded
1156                                 $cShard = $this->getContainerShard( $container, $relPath );
1157                                 // Validate and sanitize the relative path (backend-specific)
1158                                 $relPath = $this->resolveContainerPath( $container, $relPath );
1159                                 if ( $relPath !== null ) {
1160                                         // Prepend any wiki ID prefix to the container name
1161                                         $container = $this->fullContainerName( $container );
1162                                         if ( self::isValidContainerName( $container ) ) {
1163                                                 // Validate and sanitize the container name (backend-specific)
1164                                                 $container = $this->resolveContainerName( "{$container}{$cShard}" );
1165                                                 if ( $container !== null ) {
1166                                                         return array( $container, $relPath, $cShard );
1167                                                 }
1168                                         }
1169                                 }
1170                         }
1171                 }
1172                 return array( null, null, null );
1173         }
1174
1175         /**
1176          * Like resolveStoragePath() except null values are returned if
1177          * the container is sharded and the shard could not be determined.
1178          *
1179          * @see FileBackendStore::resolveStoragePath()
1180          *
1181          * @param $storagePath string
1182          * @return Array (container, path) or (null, null) if invalid
1183          */
1184         final protected function resolveStoragePathReal( $storagePath ) {
1185                 list( $container, $relPath, $cShard ) = $this->resolveStoragePath( $storagePath );
1186                 if ( $cShard !== null ) {
1187                         return array( $container, $relPath );
1188                 }
1189                 return array( null, null );
1190         }
1191
1192         /**
1193          * Get the container name shard suffix for a given path.
1194          * Any empty suffix means the container is not sharded.
1195          *
1196          * @param $container string Container name
1197          * @param $relStoragePath string Storage path relative to the container
1198          * @return string|null Returns null if shard could not be determined
1199          */
1200         final protected function getContainerShard( $container, $relPath ) {
1201                 list( $levels, $base, $repeat ) = $this->getContainerHashLevels( $container );
1202                 if ( $levels == 1 || $levels == 2 ) {
1203                         // Hash characters are either base 16 or 36
1204                         $char = ( $base == 36 ) ? '[0-9a-z]' : '[0-9a-f]';
1205                         // Get a regex that represents the shard portion of paths.
1206                         // The concatenation of the captures gives us the shard.
1207                         if ( $levels === 1 ) { // 16 or 36 shards per container
1208                                 $hashDirRegex = '(' . $char . ')';
1209                         } else { // 256 or 1296 shards per container
1210                                 if ( $repeat ) { // verbose hash dir format (e.g. "a/ab/abc")
1211                                         $hashDirRegex = $char . '/(' . $char . '{2})';
1212                                 } else { // short hash dir format (e.g. "a/b/c")
1213                                         $hashDirRegex = '(' . $char . ')/(' . $char . ')';
1214                                 }
1215                         }
1216                         // Allow certain directories to be above the hash dirs so as
1217                         // to work with FileRepo (e.g. "archive/a/ab" or "temp/a/ab").
1218                         // They must be 2+ chars to avoid any hash directory ambiguity.
1219                         $m = array();
1220                         if ( preg_match( "!^(?:[^/]{2,}/)*$hashDirRegex(?:/|$)!", $relPath, $m ) ) {
1221                                 return '.' . implode( '', array_slice( $m, 1 ) );
1222                         }
1223                         return null; // failed to match
1224                 }
1225                 return ''; // no sharding
1226         }
1227
1228         /**
1229          * Check if a storage path maps to a single shard.
1230          * Container dirs like "a", where the container shards on "x/xy",
1231          * can reside on several shards. Such paths are tricky to handle.
1232          *
1233          * @param $storagePath string Storage path
1234          * @return bool
1235          */
1236         final public function isSingleShardPathInternal( $storagePath ) {
1237                 list( $c, $r, $shard ) = $this->resolveStoragePath( $storagePath );
1238                 return ( $shard !== null );
1239         }
1240
1241         /**
1242          * Get the sharding config for a container.
1243          * If greater than 0, then all file storage paths within
1244          * the container are required to be hashed accordingly.
1245          *
1246          * @param $container string
1247          * @return Array (integer levels, integer base, repeat flag) or (0, 0, false)
1248          */
1249         final protected function getContainerHashLevels( $container ) {
1250                 if ( isset( $this->shardViaHashLevels[$container] ) ) {
1251                         $config = $this->shardViaHashLevels[$container];
1252                         $hashLevels = (int)$config['levels'];
1253                         if ( $hashLevels == 1 || $hashLevels == 2 ) {
1254                                 $hashBase = (int)$config['base'];
1255                                 if ( $hashBase == 16 || $hashBase == 36 ) {
1256                                         return array( $hashLevels, $hashBase, $config['repeat'] );
1257                                 }
1258                         }
1259                 }
1260                 return array( 0, 0, false ); // no sharding
1261         }
1262
1263         /**
1264          * Get a list of full container shard suffixes for a container
1265          *
1266          * @param $container string
1267          * @return Array
1268          */
1269         final protected function getContainerSuffixes( $container ) {
1270                 $shards = array();
1271                 list( $digits, $base ) = $this->getContainerHashLevels( $container );
1272                 if ( $digits > 0 ) {
1273                         $numShards = pow( $base, $digits );
1274                         for ( $index = 0; $index < $numShards; $index++ ) {
1275                                 $shards[] = '.' . wfBaseConvert( $index, 10, $base, $digits );
1276                         }
1277                 }
1278                 return $shards;
1279         }
1280
1281         /**
1282          * Get the full container name, including the wiki ID prefix
1283          *
1284          * @param $container string
1285          * @return string
1286          */
1287         final protected function fullContainerName( $container ) {
1288                 if ( $this->wikiId != '' ) {
1289                         return "{$this->wikiId}-$container";
1290                 } else {
1291                         return $container;
1292                 }
1293         }
1294
1295         /**
1296          * Resolve a container name, checking if it's allowed by the backend.
1297          * This is intended for internal use, such as encoding illegal chars.
1298          * Subclasses can override this to be more restrictive.
1299          *
1300          * @param $container string
1301          * @return string|null
1302          */
1303         protected function resolveContainerName( $container ) {
1304                 return $container;
1305         }
1306
1307         /**
1308          * Resolve a relative storage path, checking if it's allowed by the backend.
1309          * This is intended for internal use, such as encoding illegal chars or perhaps
1310          * getting absolute paths (e.g. FS based backends). Note that the relative path
1311          * may be the empty string (e.g. the path is simply to the container).
1312          *
1313          * @param $container string Container name
1314          * @param $relStoragePath string Storage path relative to the container
1315          * @return string|null Path or null if not valid
1316          */
1317         protected function resolveContainerPath( $container, $relStoragePath ) {
1318                 return $relStoragePath;
1319         }
1320
1321         /**
1322          * Get the cache key for a container
1323          *
1324          * @param $container string Resolved container name
1325          * @return string
1326          */
1327         private function containerCacheKey( $container ) {
1328                 return wfMemcKey( 'backend', $this->getName(), 'container', $container );
1329         }
1330
1331         /**
1332          * Set the cached info for a container
1333          *
1334          * @param $container string Resolved container name
1335          * @param $val mixed Information to cache
1336          * @return void
1337          */
1338         final protected function setContainerCache( $container, $val ) {
1339                 $this->memCache->set( $this->containerCacheKey( $container ), $val, 14*86400 );
1340         }
1341
1342         /**
1343          * Delete the cached info for a container
1344          *
1345          * @param $containers string Resolved container name
1346          * @return void
1347          */
1348         final protected function deleteContainerCache( $container ) {
1349                 if ( !$this->memCache->delete( $this->containerCacheKey( $container ) ) ) {
1350                         trigger_error( "Unable to delete stat cache for container $container." );
1351                 }
1352         }
1353
1354         /**
1355          * Do a batch lookup from cache for container stats for all containers
1356          * used in a list of container names, storage paths, or FileOp objects.
1357          *
1358          * @param $items Array
1359          * @return void
1360          */
1361         final protected function primeContainerCache( array $items ) {
1362                 wfProfileIn( __METHOD__ );
1363                 wfProfileIn( __METHOD__ . '-' . $this->name );
1364
1365                 $paths = array(); // list of storage paths
1366                 $contNames = array(); // (cache key => resolved container name)
1367                 // Get all the paths/containers from the items...
1368                 foreach ( $items as $item ) {
1369                         if ( $item instanceof FileOp ) {
1370                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1371                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1372                         } elseif ( self::isStoragePath( $item ) ) {
1373                                 $paths[] = $item;
1374                         } elseif ( is_string( $item ) ) { // full container name
1375                                 $contNames[$this->containerCacheKey( $item )] = $item;
1376                         }
1377                 }
1378                 // Get all the corresponding cache keys for paths...
1379                 foreach ( $paths as $path ) {
1380                         list( $fullCont, $r, $s ) = $this->resolveStoragePath( $path );
1381                         if ( $fullCont !== null ) { // valid path for this backend
1382                                 $contNames[$this->containerCacheKey( $fullCont )] = $fullCont;
1383                         }
1384                 }
1385
1386                 $contInfo = array(); // (resolved container name => cache value)
1387                 // Get all cache entries for these container cache keys...
1388                 $values = $this->memCache->getMulti( array_keys( $contNames ) );
1389                 foreach ( $values as $cacheKey => $val ) {
1390                         $contInfo[$contNames[$cacheKey]] = $val;
1391                 }
1392
1393                 // Populate the container process cache for the backend...
1394                 $this->doPrimeContainerCache( array_filter( $contInfo, 'is_array' ) );
1395
1396                 wfProfileOut( __METHOD__ . '-' . $this->name );
1397                 wfProfileOut( __METHOD__ );
1398         }
1399
1400         /**
1401          * Fill the backend-specific process cache given an array of
1402          * resolved container names and their corresponding cached info.
1403          * Only containers that actually exist should appear in the map.
1404          *
1405          * @param $containerInfo Array Map of resolved container names to cached info
1406          * @return void
1407          */
1408         protected function doPrimeContainerCache( array $containerInfo ) {}
1409
1410         /**
1411          * Get the cache key for a file path
1412          *
1413          * @param $path string Storage path
1414          * @return string
1415          */
1416         private function fileCacheKey( $path ) {
1417                 return wfMemcKey( 'backend', $this->getName(), 'file', sha1( $path ) );
1418         }
1419
1420         /**
1421          * Set the cached stat info for a file path
1422          *
1423          * @param $path string Storage path
1424          * @param $val mixed Information to cache
1425          * @return void
1426          */
1427         final protected function setFileCache( $path, $val ) {
1428                 $this->memCache->set( $this->fileCacheKey( $path ), $val, 7*86400 );
1429         }
1430
1431         /**
1432          * Delete the cached stat info for a file path
1433          *
1434          * @param $path string Storage path
1435          * @return void
1436          */
1437         final protected function deleteFileCache( $path ) {
1438                 if ( !$this->memCache->delete( $this->fileCacheKey( $path ) ) ) {
1439                         trigger_error( "Unable to delete stat cache for file $path." );
1440                 }
1441         }
1442
1443         /**
1444          * Do a batch lookup from cache for file stats for all paths
1445          * used in a list of storage paths or FileOp objects.
1446          *
1447          * @param $items Array List of storage paths or FileOps
1448          * @return void
1449          */
1450         final protected function primeFileCache( array $items ) {
1451                 wfProfileIn( __METHOD__ );
1452                 wfProfileIn( __METHOD__ . '-' . $this->name );
1453
1454                 $paths = array(); // list of storage paths
1455                 $pathNames = array(); // (cache key => storage path)
1456                 // Get all the paths/containers from the items...
1457                 foreach ( $items as $item ) {
1458                         if ( $item instanceof FileOp ) {
1459                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1460                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1461                         } elseif ( self::isStoragePath( $item ) ) {
1462                                 $paths[] = $item;
1463                         }
1464                 }
1465                 // Get all the corresponding cache keys for paths...
1466                 foreach ( $paths as $path ) {
1467                         list( $cont, $rel, $s ) = $this->resolveStoragePath( $path );
1468                         if ( $rel !== null ) { // valid path for this backend
1469                                 $pathNames[$this->fileCacheKey( $path )] = $path;
1470                         }
1471                 }
1472                 // Get all cache entries for these container cache keys...
1473                 $values = $this->memCache->getMulti( array_keys( $pathNames ) );
1474                 foreach ( $values as $cacheKey => $val ) {
1475                         if ( is_array( $val ) ) {
1476                                 $this->trimCache(); // limit memory
1477                                 $this->cache[$pathNames[$cacheKey]]['stat'] = $val;
1478                         }
1479                 }
1480
1481                 wfProfileOut( __METHOD__ . '-' . $this->name );
1482                 wfProfileOut( __METHOD__ );
1483         }
1484 }
1485
1486 /**
1487  * FileBackendStore helper class for performing asynchronous file operations.
1488  *
1489  * For example, calling FileBackendStore::createInternal() with the "async"
1490  * param flag may result in a Status that contains this object as a value.
1491  * This class is largely backend-specific and is mostly just "magic" to be
1492  * passed to FileBackendStore::executeOpHandlesInternal().
1493  */
1494 abstract class FileBackendStoreOpHandle {
1495         /** @var Array */
1496         public $params = array(); // params to caller functions
1497         /** @var FileBackendStore */
1498         public $backend;
1499         /** @var Array */
1500         public $resourcesToClose = array();
1501
1502         public $call; // string; name that identifies the function called
1503
1504         /**
1505          * Close all open file handles
1506          *
1507          * @return void
1508          */
1509         public function closeResources() {
1510                 array_map( 'fclose', $this->resourcesToClose );
1511         }
1512 }
1513
1514 /**
1515  * FileBackendStore helper function to handle listings that span container shards.
1516  * Do not use this class from places outside of FileBackendStore.
1517  *
1518  * @ingroup FileBackend
1519  */
1520 abstract class FileBackendStoreShardListIterator implements Iterator {
1521         /** @var FileBackendStore */
1522         protected $backend;
1523         /** @var Array */
1524         protected $params;
1525         /** @var Array */
1526         protected $shardSuffixes;
1527         protected $container; // string; full container name
1528         protected $directory; // string; resolved relative path
1529
1530         /** @var Traversable */
1531         protected $iter;
1532         protected $curShard = 0; // integer
1533         protected $pos = 0; // integer
1534
1535         /** @var Array */
1536         protected $multiShardPaths = array(); // (rel path => 1)
1537
1538         /**
1539          * @param $backend FileBackendStore
1540          * @param $container string Full storage container name
1541          * @param $dir string Storage directory relative to container
1542          * @param $suffixes Array List of container shard suffixes
1543          * @param $params Array
1544          */
1545         public function __construct(
1546                 FileBackendStore $backend, $container, $dir, array $suffixes, array $params
1547         ) {
1548                 $this->backend = $backend;
1549                 $this->container = $container;
1550                 $this->directory = $dir;
1551                 $this->shardSuffixes = $suffixes;
1552                 $this->params = $params;
1553         }
1554
1555         /**
1556          * @see Iterator::current()
1557          * @return string|bool String or false
1558          */
1559         public function current() {
1560                 if ( is_array( $this->iter ) ) {
1561                         return current( $this->iter );
1562                 } else {
1563                         return $this->iter->current();
1564                 }
1565         }
1566
1567         /**
1568          * @see Iterator::key()
1569          * @return integer
1570          */
1571         public function key() {
1572                 return $this->pos;
1573         }
1574
1575         /**
1576          * @see Iterator::next()
1577          * @return void
1578          */
1579         public function next() {
1580                 ++$this->pos;
1581                 if ( is_array( $this->iter ) ) {
1582                         next( $this->iter );
1583                 } else {
1584                         $this->iter->next();
1585                 }
1586                 // Filter out items that we already listed
1587                 $this->filterViaNext();
1588                 // Find the next non-empty shard if no elements are left
1589                 $this->nextShardIteratorIfNotValid();
1590         }
1591
1592         /**
1593          * @see Iterator::rewind()
1594          * @return void
1595          */
1596         public function rewind() {
1597                 $this->pos = 0;
1598                 $this->curShard = 0;
1599                 $this->setIteratorFromCurrentShard();
1600                 // Filter out items that we already listed
1601                 $this->filterViaNext();
1602                 // Find the next non-empty shard if this one has no elements
1603                 $this->nextShardIteratorIfNotValid();
1604         }
1605
1606         /**
1607          * @see Iterator::valid()
1608          * @return bool
1609          */
1610         public function valid() {
1611                 if ( $this->iter === null ) {
1612                         return false; // some failure?
1613                 } elseif ( is_array( $this->iter ) ) {
1614                         return ( current( $this->iter ) !== false ); // no paths can have this value
1615                 } else {
1616                         return $this->iter->valid();
1617                 }
1618         }
1619
1620         /**
1621          * Filter out duplicate items by advancing to the next ones
1622          */
1623         protected function filterViaNext() {
1624                 while ( $this->iter->valid() ) {
1625                         $rel = $this->iter->current(); // path relative to given directory
1626                         $path = $this->params['dir'] . "/{$rel}"; // full storage path
1627                         if ( !$this->backend->isSingleShardPathInternal( $path ) ) {
1628                                 // Don't keep listing paths that are on multiple shards
1629                                 if ( isset( $this->multiShardPaths[$rel] ) ) {
1630                                         $this->iter->next(); // we already listed this path
1631                                 } else {
1632                                         $this->multiShardPaths[$rel] = 1;
1633                                         break;
1634                                 }
1635                         }
1636                 }
1637         }
1638
1639         /**
1640          * If the list iterator for this container shard is out of items,
1641          * then move on to the next container that has items.
1642          * If there are none, then it advances to the last container.
1643          */
1644         protected function nextShardIteratorIfNotValid() {
1645                 while ( !$this->valid() ) {
1646                         if ( ++$this->curShard >= count( $this->shardSuffixes ) ) {
1647                                 break; // no more container shards
1648                         }
1649                         $this->setIteratorFromCurrentShard();
1650                 }
1651         }
1652
1653         /**
1654          * Set the list iterator to that of the current container shard
1655          */
1656         protected function setIteratorFromCurrentShard() {
1657                 $suffix = $this->shardSuffixes[$this->curShard];
1658                 $this->iter = $this->listFromShard(
1659                         "{$this->container}{$suffix}", $this->directory, $this->params );
1660         }
1661
1662         /**
1663          * Get the list for a given container shard
1664          *
1665          * @param $container string Resolved container name
1666          * @param $dir string Resolved path relative to container
1667          * @param $params Array
1668          * @return Traversable|Array|null
1669          */
1670         abstract protected function listFromShard( $container, $dir, array $params );
1671 }
1672
1673 /**
1674  * Iterator for listing directories
1675  */
1676 class FileBackendStoreShardDirIterator extends FileBackendStoreShardListIterator {
1677         protected function listFromShard( $container, $dir, array $params ) {
1678                 return $this->backend->getDirectoryListInternal( $container, $dir, $params );
1679         }
1680 }
1681
1682 /**
1683  * Iterator for listing regular files
1684  */
1685 class FileBackendStoreShardFileIterator extends FileBackendStoreShardListIterator {
1686         protected function listFromShard( $container, $dir, array $params ) {
1687                 return $this->backend->getFileListInternal( $container, $dir, $params );
1688         }
1689 }