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                 wfProfileIn( __METHOD__ );
 947                 wfProfileIn( __METHOD__ . '-' . $this->name );
 948                 $status = Status::newGood();
 949
 950                 $async = ( $this->parallelize === 'implicit' );
 951                 $maxConcurrency = $this->concurrency; // throttle
 952
 953                 $statuses = array(); // array of (index => Status)
 954                 $fileOpHandles = array(); // list of (index => handle) arrays
 955                 $curFileOpHandles = array(); // current handle batch
 956                 // Perform the sync-only ops and build up op handles for the async ops...
 957                 foreach ( $ops as $index => $params ) {
 958                         $method = $params['op'] . 'Internal'; // e.g. "storeInternal"
 959                         if ( !MWInit::methodExists( __CLASS__, $method ) ) {
 960                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 961                                 wfProfileOut( __METHOD__ );
 962                                 throw new MWException( "Operation '{$params['op']}' is not supported." );
 963                         }
 964                         $subStatus = $this->$method( array( 'async' => $async ) + $params );
 965                         if ( $subStatus->value instanceof FileBackendStoreOpHandle ) { // async
 966                                 if ( count( $curFileOpHandles ) >= $maxConcurrency ) {
 967                                         $fileOpHandles[] = $curFileOpHandles; // push this batch
 968                                         $curFileOpHandles = array();
 969                                 }
 970                                 $curFileOpHandles[$index] = $subStatus->value; // keep index
 971                         } else { // error or completed
 972                                 $statuses[$index] = $subStatus; // keep index
 973                         }
 974                 }
 975                 if ( count( $curFileOpHandles ) ) {
 976                         $fileOpHandles[] = $curFileOpHandles; // last batch
 977                 }
 978                 // Do all the async ops that can be done concurrently...
 979                 foreach ( $fileOpHandles as $fileHandleBatch ) {
 980                         $statuses = $statuses + $this->executeOpHandlesInternal( $fileHandleBatch );
 981                 }
 982                 // Marshall and merge all the responses...
 983                 foreach ( $statuses as $index => $subStatus ) {
 984                         $status->merge( $subStatus );
 985                         if ( $subStatus->isOK() ) {
 986                                 $status->success[$index] = true;
 987                                 ++$status->successCount;
 988                         } else {
 989                                 $status->success[$index] = false;
 990                                 ++$status->failCount;
 991                         }
 992                 }
 993
 994                 wfProfileOut( __METHOD__ . '-' . $this->name );
 995                 wfProfileOut( __METHOD__ );
 996                 return $status;
 997         }
 998
 999         /**
1000          * Execute a list of FileBackendStoreOpHandle handles in parallel.
1001          * The resulting Status object fields will correspond
1002          * to the order in which the handles where given.
1003          *
1004          * @param $handles Array List of FileBackendStoreOpHandle objects
1005          * @return Array Map of Status objects
1006          * @throws MWException
1007          */
1008         final public function executeOpHandlesInternal( array $fileOpHandles ) {
1009                 wfProfileIn( __METHOD__ );
1010                 wfProfileIn( __METHOD__ . '-' . $this->name );
1011                 foreach ( $fileOpHandles as $fileOpHandle ) {
1012                         if ( !( $fileOpHandle instanceof FileBackendStoreOpHandle ) ) {
1013                                 throw new MWException( "Given a non-FileBackendStoreOpHandle object." );
1014                         } elseif ( $fileOpHandle->backend->getName() !== $this->getName() ) {
1015                                 throw new MWException( "Given a FileBackendStoreOpHandle for the wrong backend." );
1016                         }
1017                 }
1018                 $res = $this->doExecuteOpHandlesInternal( $fileOpHandles );
1019                 foreach ( $fileOpHandles as $fileOpHandle ) {
1020                         $fileOpHandle->closeResources();
1021                 }
1022                 wfProfileOut( __METHOD__ . '-' . $this->name );
1023                 wfProfileOut( __METHOD__ );
1024                 return $res;
1025         }
1026
1027         /**
1028          * @see FileBackendStore::executeOpHandlesInternal()
1029          * @return Array List of corresponding Status objects
1030          * @throws MWException
1031          */
1032         protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
1033                 foreach ( $fileOpHandles as $fileOpHandle ) { // OK if empty
1034                         throw new MWException( "This backend supports no asynchronous operations." );
1035                 }
1036                 return array();
1037         }
1038
1039         /**
1040          * @see FileBackend::clearCache()
1041          */
1042         final public function clearCache( array $paths = null ) {
1043                 if ( is_array( $paths ) ) {
1044                         $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1045                         $paths = array_filter( $paths, 'strlen' ); // remove nulls
1046                 }
1047                 if ( $paths === null ) {
1048                         $this->cache = array();
1049                         $this->expensiveCache = array();
1050                 } else {
1051                         foreach ( $paths as $path ) {
1052                                 unset( $this->cache[$path] );
1053                                 unset( $this->expensiveCache[$path] );
1054                         }
1055                 }
1056                 $this->doClearCache( $paths );
1057         }
1058
1059         /**
1060          * Clears any additional stat caches for storage paths
1061          *
1062          * @see FileBackend::clearCache()
1063          *
1064          * @param $paths Array Storage paths (optional)
1065          * @return void
1066          */
1067         protected function doClearCache( array $paths = null ) {}
1068
1069         /**
1070          * Is this a key/value store where directories are just virtual?
1071          * Virtual directories exists in so much as files exists that are
1072          * prefixed with the directory path followed by a forward slash.
1073          *
1074          * @return bool
1075          */
1076         abstract protected function directoriesAreVirtual();
1077
1078         /**
1079          * Move a cache entry to the top (such as when accessed)
1080          *
1081          * @param $path string Storage path
1082          * @return void
1083          */
1084         protected function pingCache( $path ) {
1085                 if ( isset( $this->cache[$path] ) ) {
1086                         $tmp = $this->cache[$path];
1087                         unset( $this->cache[$path] );
1088                         $this->cache[$path] = $tmp;
1089                 }
1090         }
1091
1092         /**
1093          * Prune the inexpensive cache if it is too big to add an item
1094          *
1095          * @return void
1096          */
1097         protected function trimCache() {
1098                 if ( count( $this->cache ) >= $this->maxCacheSize ) {
1099                         reset( $this->cache );
1100                         unset( $this->cache[key( $this->cache )] );
1101                 }
1102         }
1103
1104         /**
1105          * Move a cache entry to the top (such as when accessed)
1106          *
1107          * @param $path string Storage path
1108          * @return void
1109          */
1110         protected function pingExpensiveCache( $path ) {
1111                 if ( isset( $this->expensiveCache[$path] ) ) {
1112                         $tmp = $this->expensiveCache[$path];
1113                         unset( $this->expensiveCache[$path] );
1114                         $this->expensiveCache[$path] = $tmp;
1115                 }
1116         }
1117
1118         /**
1119          * Prune the expensive cache if it is too big to add an item
1120          *
1121          * @return void
1122          */
1123         protected function trimExpensiveCache() {
1124                 if ( count( $this->expensiveCache ) >= $this->maxExpensiveCacheSize ) {
1125                         reset( $this->expensiveCache );
1126                         unset( $this->expensiveCache[key( $this->expensiveCache )] );
1127                 }
1128         }
1129
1130         /**
1131          * Check if a container name is valid.
1132          * This checks for for length and illegal characters.
1133          *
1134          * @param $container string
1135          * @return bool
1136          */
1137         final protected static function isValidContainerName( $container ) {
1138                 // This accounts for Swift and S3 restrictions while leaving room
1139                 // for things like '.xxx' (hex shard chars) or '.seg' (segments).
1140                 // This disallows directory separators or traversal characters.
1141                 // Note that matching strings URL encode to the same string;
1142                 // in Swift, the length restriction is *after* URL encoding.
1143                 return preg_match( '/^[a-z0-9][a-z0-9-_]{0,199}$/i', $container );
1144         }
1145
1146         /**
1147          * Splits a storage path into an internal container name,
1148          * an internal relative file name, and a container shard suffix.
1149          * Any shard suffix is already appended to the internal container name.
1150          * This also checks that the storage path is valid and within this backend.
1151          *
1152          * If the container is sharded but a suffix could not be determined,
1153          * this means that the path can only refer to a directory and can only
1154          * be scanned by looking in all the container shards.
1155          *
1156          * @param $storagePath string
1157          * @return Array (container, path, container suffix) or (null, null, null) if invalid
1158          */
1159         final protected function resolveStoragePath( $storagePath ) {
1160                 list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
1161                 if ( $backend === $this->name ) { // must be for this backend
1162                         $relPath = self::normalizeContainerPath( $relPath );
1163                         if ( $relPath !== null ) {
1164                                 // Get shard for the normalized path if this container is sharded
1165                                 $cShard = $this->getContainerShard( $container, $relPath );
1166                                 // Validate and sanitize the relative path (backend-specific)
1167                                 $relPath = $this->resolveContainerPath( $container, $relPath );
1168                                 if ( $relPath !== null ) {
1169                                         // Prepend any wiki ID prefix to the container name
1170                                         $container = $this->fullContainerName( $container );
1171                                         if ( self::isValidContainerName( $container ) ) {
1172                                                 // Validate and sanitize the container name (backend-specific)
1173                                                 $container = $this->resolveContainerName( "{$container}{$cShard}" );
1174                                                 if ( $container !== null ) {
1175                                                         return array( $container, $relPath, $cShard );
1176                                                 }
1177                                         }
1178                                 }
1179                         }
1180                 }
1181                 return array( null, null, null );
1182         }
1183
1184         /**
1185          * Like resolveStoragePath() except null values are returned if
1186          * the container is sharded and the shard could not be determined.
1187          *
1188          * @see FileBackendStore::resolveStoragePath()
1189          *
1190          * @param $storagePath string
1191          * @return Array (container, path) or (null, null) if invalid
1192          */
1193         final protected function resolveStoragePathReal( $storagePath ) {
1194                 list( $container, $relPath, $cShard ) = $this->resolveStoragePath( $storagePath );
1195                 if ( $cShard !== null ) {
1196                         return array( $container, $relPath );
1197                 }
1198                 return array( null, null );
1199         }
1200
1201         /**
1202          * Get the container name shard suffix for a given path.
1203          * Any empty suffix means the container is not sharded.
1204          *
1205          * @param $container string Container name
1206          * @param $relStoragePath string Storage path relative to the container
1207          * @return string|null Returns null if shard could not be determined
1208          */
1209         final protected function getContainerShard( $container, $relPath ) {
1210                 list( $levels, $base, $repeat ) = $this->getContainerHashLevels( $container );
1211                 if ( $levels == 1 || $levels == 2 ) {
1212                         // Hash characters are either base 16 or 36
1213                         $char = ( $base == 36 ) ? '[0-9a-z]' : '[0-9a-f]';
1214                         // Get a regex that represents the shard portion of paths.
1215                         // The concatenation of the captures gives us the shard.
1216                         if ( $levels === 1 ) { // 16 or 36 shards per container
1217                                 $hashDirRegex = '(' . $char . ')';
1218                         } else { // 256 or 1296 shards per container
1219                                 if ( $repeat ) { // verbose hash dir format (e.g. "a/ab/abc")
1220                                         $hashDirRegex = $char . '/(' . $char . '{2})';
1221                                 } else { // short hash dir format (e.g. "a/b/c")
1222                                         $hashDirRegex = '(' . $char . ')/(' . $char . ')';
1223                                 }
1224                         }
1225                         // Allow certain directories to be above the hash dirs so as
1226                         // to work with FileRepo (e.g. "archive/a/ab" or "temp/a/ab").
1227                         // They must be 2+ chars to avoid any hash directory ambiguity.
1228                         $m = array();
1229                         if ( preg_match( "!^(?:[^/]{2,}/)*$hashDirRegex(?:/|$)!", $relPath, $m ) ) {
1230                                 return '.' . implode( '', array_slice( $m, 1 ) );
1231                         }
1232                         return null; // failed to match
1233                 }
1234                 return ''; // no sharding
1235         }
1236
1237         /**
1238          * Check if a storage path maps to a single shard.
1239          * Container dirs like "a", where the container shards on "x/xy",
1240          * can reside on several shards. Such paths are tricky to handle.
1241          *
1242          * @param $storagePath string Storage path
1243          * @return bool
1244          */
1245         final public function isSingleShardPathInternal( $storagePath ) {
1246                 list( $c, $r, $shard ) = $this->resolveStoragePath( $storagePath );
1247                 return ( $shard !== null );
1248         }
1249
1250         /**
1251          * Get the sharding config for a container.
1252          * If greater than 0, then all file storage paths within
1253          * the container are required to be hashed accordingly.
1254          *
1255          * @param $container string
1256          * @return Array (integer levels, integer base, repeat flag) or (0, 0, false)
1257          */
1258         final protected function getContainerHashLevels( $container ) {
1259                 if ( isset( $this->shardViaHashLevels[$container] ) ) {
1260                         $config = $this->shardViaHashLevels[$container];
1261                         $hashLevels = (int)$config['levels'];
1262                         if ( $hashLevels == 1 || $hashLevels == 2 ) {
1263                                 $hashBase = (int)$config['base'];
1264                                 if ( $hashBase == 16 || $hashBase == 36 ) {
1265                                         return array( $hashLevels, $hashBase, $config['repeat'] );
1266                                 }
1267                         }
1268                 }
1269                 return array( 0, 0, false ); // no sharding
1270         }
1271
1272         /**
1273          * Get a list of full container shard suffixes for a container
1274          *
1275          * @param $container string
1276          * @return Array
1277          */
1278         final protected function getContainerSuffixes( $container ) {
1279                 $shards = array();
1280                 list( $digits, $base ) = $this->getContainerHashLevels( $container );
1281                 if ( $digits > 0 ) {
1282                         $numShards = pow( $base, $digits );
1283                         for ( $index = 0; $index < $numShards; $index++ ) {
1284                                 $shards[] = '.' . wfBaseConvert( $index, 10, $base, $digits );
1285                         }
1286                 }
1287                 return $shards;
1288         }
1289
1290         /**
1291          * Get the full container name, including the wiki ID prefix
1292          *
1293          * @param $container string
1294          * @return string
1295          */
1296         final protected function fullContainerName( $container ) {
1297                 if ( $this->wikiId != '' ) {
1298                         return "{$this->wikiId}-$container";
1299                 } else {
1300                         return $container;
1301                 }
1302         }
1303
1304         /**
1305          * Resolve a container name, checking if it's allowed by the backend.
1306          * This is intended for internal use, such as encoding illegal chars.
1307          * Subclasses can override this to be more restrictive.
1308          *
1309          * @param $container string
1310          * @return string|null
1311          */
1312         protected function resolveContainerName( $container ) {
1313                 return $container;
1314         }
1315
1316         /**
1317          * Resolve a relative storage path, checking if it's allowed by the backend.
1318          * This is intended for internal use, such as encoding illegal chars or perhaps
1319          * getting absolute paths (e.g. FS based backends). Note that the relative path
1320          * may be the empty string (e.g. the path is simply to the container).
1321          *
1322          * @param $container string Container name
1323          * @param $relStoragePath string Storage path relative to the container
1324          * @return string|null Path or null if not valid
1325          */
1326         protected function resolveContainerPath( $container, $relStoragePath ) {
1327                 return $relStoragePath;
1328         }
1329
1330         /**
1331          * Get the cache key for a container
1332          *
1333          * @param $container string Resolved container name
1334          * @return string
1335          */
1336         private function containerCacheKey( $container ) {
1337                 return wfMemcKey( 'backend', $this->getName(), 'container', $container );
1338         }
1339
1340         /**
1341          * Set the cached info for a container
1342          *
1343          * @param $container string Resolved container name
1344          * @param $val mixed Information to cache
1345          * @return void
1346          */
1347         final protected function setContainerCache( $container, $val ) {
1348                 $this->memCache->set( $this->containerCacheKey( $container ), $val, 14*86400 );
1349         }
1350
1351         /**
1352          * Delete the cached info for a container
1353          *
1354          * @param $containers string Resolved container name
1355          * @return void
1356          */
1357         final protected function deleteContainerCache( $container ) {
1358                 if ( !$this->memCache->delete( $this->containerCacheKey( $container ) ) ) {
1359                         trigger_error( "Unable to delete stat cache for container $container." );
1360                 }
1361         }
1362
1363         /**
1364          * Do a batch lookup from cache for container stats for all containers
1365          * used in a list of container names, storage paths, or FileOp objects.
1366          *
1367          * @param $items Array
1368          * @return void
1369          */
1370         final protected function primeContainerCache( array $items ) {
1371                 wfProfileIn( __METHOD__ );
1372                 wfProfileIn( __METHOD__ . '-' . $this->name );
1373
1374                 $paths = array(); // list of storage paths
1375                 $contNames = array(); // (cache key => resolved container name)
1376                 // Get all the paths/containers from the items...
1377                 foreach ( $items as $item ) {
1378                         if ( $item instanceof FileOp ) {
1379                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1380                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1381                         } elseif ( self::isStoragePath( $item ) ) {
1382                                 $paths[] = $item;
1383                         } elseif ( is_string( $item ) ) { // full container name
1384                                 $contNames[$this->containerCacheKey( $item )] = $item;
1385                         }
1386                 }
1387                 // Get all the corresponding cache keys for paths...
1388                 foreach ( $paths as $path ) {
1389                         list( $fullCont, $r, $s ) = $this->resolveStoragePath( $path );
1390                         if ( $fullCont !== null ) { // valid path for this backend
1391                                 $contNames[$this->containerCacheKey( $fullCont )] = $fullCont;
1392                         }
1393                 }
1394
1395                 $contInfo = array(); // (resolved container name => cache value)
1396                 // Get all cache entries for these container cache keys...
1397                 $values = $this->memCache->getMulti( array_keys( $contNames ) );
1398                 foreach ( $values as $cacheKey => $val ) {
1399                         $contInfo[$contNames[$cacheKey]] = $val;
1400                 }
1401
1402                 // Populate the container process cache for the backend...
1403                 $this->doPrimeContainerCache( array_filter( $contInfo, 'is_array' ) );
1404
1405                 wfProfileOut( __METHOD__ . '-' . $this->name );
1406                 wfProfileOut( __METHOD__ );
1407         }
1408
1409         /**
1410          * Fill the backend-specific process cache given an array of
1411          * resolved container names and their corresponding cached info.
1412          * Only containers that actually exist should appear in the map.
1413          *
1414          * @param $containerInfo Array Map of resolved container names to cached info
1415          * @return void
1416          */
1417         protected function doPrimeContainerCache( array $containerInfo ) {}
1418
1419         /**
1420          * Get the cache key for a file path
1421          *
1422          * @param $path string Storage path
1423          * @return string
1424          */
1425         private function fileCacheKey( $path ) {
1426                 return wfMemcKey( 'backend', $this->getName(), 'file', sha1( $path ) );
1427         }
1428
1429         /**
1430          * Set the cached stat info for a file path
1431          *
1432          * @param $path string Storage path
1433          * @param $val mixed Information to cache
1434          * @return void
1435          */
1436         final protected function setFileCache( $path, $val ) {
1437                 $this->memCache->set( $this->fileCacheKey( $path ), $val, 7*86400 );
1438         }
1439
1440         /**
1441          * Delete the cached stat info for a file path
1442          *
1443          * @param $path string Storage path
1444          * @return void
1445          */
1446         final protected function deleteFileCache( $path ) {
1447                 if ( !$this->memCache->delete( $this->fileCacheKey( $path ) ) ) {
1448                         trigger_error( "Unable to delete stat cache for file $path." );
1449                 }
1450         }
1451
1452         /**
1453          * Do a batch lookup from cache for file stats for all paths
1454          * used in a list of storage paths or FileOp objects.
1455          *
1456          * @param $items Array List of storage paths or FileOps
1457          * @return void
1458          */
1459         final protected function primeFileCache( array $items ) {
1460                 wfProfileIn( __METHOD__ );
1461                 wfProfileIn( __METHOD__ . '-' . $this->name );
1462
1463                 $paths = array(); // list of storage paths
1464                 $pathNames = array(); // (cache key => storage path)
1465                 // Get all the paths/containers from the items...
1466                 foreach ( $items as $item ) {
1467                         if ( $item instanceof FileOp ) {
1468                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1469                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1470                         } elseif ( self::isStoragePath( $item ) ) {
1471                                 $paths[] = $item;
1472                         }
1473                 }
1474                 // Get all the corresponding cache keys for paths...
1475                 foreach ( $paths as $path ) {
1476                         list( $cont, $rel, $s ) = $this->resolveStoragePath( $path );
1477                         if ( $rel !== null ) { // valid path for this backend
1478                                 $pathNames[$this->fileCacheKey( $path )] = $path;
1479                         }
1480                 }
1481                 // Get all cache entries for these container cache keys...
1482                 $values = $this->memCache->getMulti( array_keys( $pathNames ) );
1483                 foreach ( $values as $cacheKey => $val ) {
1484                         if ( is_array( $val ) ) {
1485                                 $this->trimCache(); // limit memory
1486                                 $this->cache[$pathNames[$cacheKey]]['stat'] = $val;
1487                         }
1488                 }
1489
1490                 wfProfileOut( __METHOD__ . '-' . $this->name );
1491                 wfProfileOut( __METHOD__ );
1492         }
1493 }
1494
1495 /**
1496  * FileBackendStore helper class for performing asynchronous file operations.
1497  *
1498  * For example, calling FileBackendStore::createInternal() with the "async"
1499  * param flag may result in a Status that contains this object as a value.
1500  * This class is largely backend-specific and is mostly just "magic" to be
1501  * passed to FileBackendStore::executeOpHandlesInternal().
1502  */
1503 abstract class FileBackendStoreOpHandle {
1504         /** @var Array */
1505         public $params = array(); // params to caller functions
1506         /** @var FileBackendStore */
1507         public $backend;
1508         /** @var Array */
1509         public $resourcesToClose = array();
1510
1511         public $call; // string; name that identifies the function called
1512
1513         /**
1514          * Close all open file handles
1515          *
1516          * @return void
1517          */
1518         public function closeResources() {
1519                 array_map( 'fclose', $this->resourcesToClose );
1520         }
1521 }
1522
1523 /**
1524  * FileBackendStore helper function to handle listings that span container shards.
1525  * Do not use this class from places outside of FileBackendStore.
1526  *
1527  * @ingroup FileBackend
1528  */
1529 abstract class FileBackendStoreShardListIterator implements Iterator {
1530         /** @var FileBackendStore */
1531         protected $backend;
1532         /** @var Array */
1533         protected $params;
1534         /** @var Array */
1535         protected $shardSuffixes;
1536         protected $container; // string; full container name
1537         protected $directory; // string; resolved relative path
1538
1539         /** @var Traversable */
1540         protected $iter;
1541         protected $curShard = 0; // integer
1542         protected $pos = 0; // integer
1543
1544         /** @var Array */
1545         protected $multiShardPaths = array(); // (rel path => 1)
1546
1547         /**
1548          * @param $backend FileBackendStore
1549          * @param $container string Full storage container name
1550          * @param $dir string Storage directory relative to container
1551          * @param $suffixes Array List of container shard suffixes
1552          * @param $params Array
1553          */
1554         public function __construct(
1555                 FileBackendStore $backend, $container, $dir, array $suffixes, array $params
1556         ) {
1557                 $this->backend = $backend;
1558                 $this->container = $container;
1559                 $this->directory = $dir;
1560                 $this->shardSuffixes = $suffixes;
1561                 $this->params = $params;
1562         }
1563
1564         /**
1565          * @see Iterator::current()
1566          * @return string|bool String or false
1567          */
1568         public function current() {
1569                 if ( is_array( $this->iter ) ) {
1570                         return current( $this->iter );
1571                 } else {
1572                         return $this->iter->current();
1573                 }
1574         }
1575
1576         /**
1577          * @see Iterator::key()
1578          * @return integer
1579          */
1580         public function key() {
1581                 return $this->pos;
1582         }
1583
1584         /**
1585          * @see Iterator::next()
1586          * @return void
1587          */
1588         public function next() {
1589                 ++$this->pos;
1590                 if ( is_array( $this->iter ) ) {
1591                         next( $this->iter );
1592                 } else {
1593                         $this->iter->next();
1594                 }
1595                 // Filter out items that we already listed
1596                 $this->filterViaNext();
1597                 // Find the next non-empty shard if no elements are left
1598                 $this->nextShardIteratorIfNotValid();
1599         }
1600
1601         /**
1602          * @see Iterator::rewind()
1603          * @return void
1604          */
1605         public function rewind() {
1606                 $this->pos = 0;
1607                 $this->curShard = 0;
1608                 $this->setIteratorFromCurrentShard();
1609                 // Filter out items that we already listed
1610                 $this->filterViaNext();
1611                 // Find the next non-empty shard if this one has no elements
1612                 $this->nextShardIteratorIfNotValid();
1613         }
1614
1615         /**
1616          * @see Iterator::valid()
1617          * @return bool
1618          */
1619         public function valid() {
1620                 if ( $this->iter === null ) {
1621                         return false; // some failure?
1622                 } elseif ( is_array( $this->iter ) ) {
1623                         return ( current( $this->iter ) !== false ); // no paths can have this value
1624                 } else {
1625                         return $this->iter->valid();
1626                 }
1627         }
1628
1629         /**
1630          * Filter out duplicate items by advancing to the next ones
1631          */
1632         protected function filterViaNext() {
1633                 while ( $this->iter->valid() ) {
1634                         $rel = $this->iter->current(); // path relative to given directory
1635                         $path = $this->params['dir'] . "/{$rel}"; // full storage path
1636                         if ( !$this->backend->isSingleShardPathInternal( $path ) ) {
1637                                 // Don't keep listing paths that are on multiple shards
1638                                 if ( isset( $this->multiShardPaths[$rel] ) ) {
1639                                         $this->iter->next(); // we already listed this path
1640                                 } else {
1641                                         $this->multiShardPaths[$rel] = 1;
1642                                         break;
1643                                 }
1644                         }
1645                 }
1646         }
1647
1648         /**
1649          * If the list iterator for this container shard is out of items,
1650          * then move on to the next container that has items.
1651          * If there are none, then it advances to the last container.
1652          */
1653         protected function nextShardIteratorIfNotValid() {
1654                 while ( !$this->valid() ) {
1655                         if ( ++$this->curShard >= count( $this->shardSuffixes ) ) {
1656                                 break; // no more container shards
1657                         }
1658                         $this->setIteratorFromCurrentShard();
1659                 }
1660         }
1661
1662         /**
1663          * Set the list iterator to that of the current container shard
1664          */
1665         protected function setIteratorFromCurrentShard() {
1666                 $suffix = $this->shardSuffixes[$this->curShard];
1667                 $this->iter = $this->listFromShard(
1668                         "{$this->container}{$suffix}", $this->directory, $this->params );
1669         }
1670
1671         /**
1672          * Get the list for a given container shard
1673          *
1674          * @param $container string Resolved container name
1675          * @param $dir string Resolved path relative to container
1676          * @param $params Array
1677          * @return Traversable|Array|null
1678          */
1679         abstract protected function listFromShard( $container, $dir, array $params );
1680 }
1681
1682 /**
1683  * Iterator for listing directories
1684  */
1685 class FileBackendStoreShardDirIterator extends FileBackendStoreShardListIterator {
1686         protected function listFromShard( $container, $dir, array $params ) {
1687                 return $this->backend->getDirectoryListInternal( $container, $dir, $params );
1688         }
1689 }
1690
1691 /**
1692  * Iterator for listing regular files
1693  */
1694 class FileBackendStoreShardFileIterator extends FileBackendStoreShardListIterator {
1695         protected function listFromShard( $container, $dir, array $params ) {
1696                 return $this->backend->getFileListInternal( $container, $dir, $params );
1697         }
1698 }