includes/filebackend/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         /** @var ProcessCacheLRU */
  42         protected $cheapCache; // Map of paths to small (RAM/disk) cache items
  43         /** @var ProcessCacheLRU */
  44         protected $expensiveCache; // Map of paths to large (RAM/disk) cache items
  45
  46         /** @var Array Map of container names to sharding settings */
  47         protected $shardViaHashLevels = array(); // (container name => config array)
  48
  49         protected $maxFileSize = 4294967296; // integer bytes (4GiB)
  50
  51         /**
  52          * @see FileBackend::__construct()
  53          *
  54          * @param $config Array
  55          */
  56         public function __construct( array $config ) {
  57                 parent::__construct( $config );
  58                 $this->memCache       = new EmptyBagOStuff(); // disabled by default
  59                 $this->cheapCache     = new ProcessCacheLRU( 300 );
  60                 $this->expensiveCache = new ProcessCacheLRU( 5 );
  61         }
  62
  63         /**
  64          * Get the maximum allowable file size given backend
  65          * medium restrictions and basic performance constraints.
  66          * Do not call this function from places outside FileBackend and FileOp.
  67          *
  68          * @return integer Bytes
  69          */
  70         final public function maxFileSizeInternal() {
  71                 return $this->maxFileSize;
  72         }
  73
  74         /**
  75          * Check if a file can be created at a given storage path.
  76          * FS backends should check if the parent directory exists and the file is writable.
  77          * Backends using key/value stores should check if the container exists.
  78          *
  79          * @param $storagePath string
  80          * @return bool
  81          */
  82         abstract public function isPathUsableInternal( $storagePath );
  83
  84         /**
  85          * Create a file in the backend with the given contents.
  86          * Do not call this function from places outside FileBackend and FileOp.
  87          *
  88          * $params include:
  89          *   - content       : the raw file contents
  90          *   - dst           : destination storage path
  91          *   - overwrite     : overwrite any file that exists at the destination
  92          *   - disposition   : Content-Disposition header value for 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                         if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
 110                                 $this->deleteFileCache( $params['dst'] ); // persistent cache
 111                         }
 112                 }
 113                 wfProfileOut( __METHOD__ . '-' . $this->name );
 114                 wfProfileOut( __METHOD__ );
 115                 return $status;
 116         }
 117
 118         /**
 119          * @see FileBackendStore::createInternal()
 120          */
 121         abstract protected function doCreateInternal( array $params );
 122
 123         /**
 124          * Store a file into the backend from a file on disk.
 125          * Do not call this function from places outside FileBackend and FileOp.
 126          *
 127          * $params include:
 128          *   - src           : source path on disk
 129          *   - dst           : destination storage path
 130          *   - overwrite     : overwrite any file that exists at the destination
 131          *   - disposition   : Content-Disposition header value for the destination
 132          *   - async         : Status will be returned immediately if supported.
 133          *                     If the status is OK, then its value field will be
 134          *                     set to a FileBackendStoreOpHandle object.
 135          *
 136          * @param $params Array
 137          * @return Status
 138          */
 139         final public function storeInternal( array $params ) {
 140                 wfProfileIn( __METHOD__ );
 141                 wfProfileIn( __METHOD__ . '-' . $this->name );
 142                 if ( filesize( $params['src'] ) > $this->maxFileSizeInternal() ) {
 143                         $status = Status::newFatal( 'backend-fail-maxsize',
 144                                 $params['dst'], $this->maxFileSizeInternal() );
 145                 } else {
 146                         $status = $this->doStoreInternal( $params );
 147                         $this->clearCache( array( $params['dst'] ) );
 148                         if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
 149                                 $this->deleteFileCache( $params['dst'] ); // persistent cache
 150                         }
 151                 }
 152                 wfProfileOut( __METHOD__ . '-' . $this->name );
 153                 wfProfileOut( __METHOD__ );
 154                 return $status;
 155         }
 156
 157         /**
 158          * @see FileBackendStore::storeInternal()
 159          */
 160         abstract protected function doStoreInternal( array $params );
 161
 162         /**
 163          * Copy a file from one storage path to another in the backend.
 164          * Do not call this function from places outside FileBackend and FileOp.
 165          *
 166          * $params include:
 167          *   - src           : source storage path
 168          *   - dst           : destination storage path
 169          *   - overwrite     : overwrite any file that exists at the destination
 170          *   - disposition   : Content-Disposition header value for the destination
 171          *   - async         : Status will be returned immediately if supported.
 172          *                     If the status is OK, then its value field will be
 173          *                     set to a FileBackendStoreOpHandle object.
 174          *
 175          * @param $params Array
 176          * @return Status
 177          */
 178         final public function copyInternal( array $params ) {
 179                 wfProfileIn( __METHOD__ );
 180                 wfProfileIn( __METHOD__ . '-' . $this->name );
 181                 $status = $this->doCopyInternal( $params );
 182                 $this->clearCache( array( $params['dst'] ) );
 183                 if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
 184                         $this->deleteFileCache( $params['dst'] ); // persistent cache
 185                 }
 186                 wfProfileOut( __METHOD__ . '-' . $this->name );
 187                 wfProfileOut( __METHOD__ );
 188                 return $status;
 189         }
 190
 191         /**
 192          * @see FileBackendStore::copyInternal()
 193          */
 194         abstract protected function doCopyInternal( array $params );
 195
 196         /**
 197          * Delete a file at the storage path.
 198          * Do not call this function from places outside FileBackend and FileOp.
 199          *
 200          * $params include:
 201          *   - src                 : source storage path
 202          *   - ignoreMissingSource : do nothing if the source file does not exist
 203          *   - async               : Status will be returned immediately if supported.
 204          *                           If the status is OK, then its value field will be
 205          *                           set to a FileBackendStoreOpHandle object.
 206          *
 207          * @param $params Array
 208          * @return Status
 209          */
 210         final public function deleteInternal( array $params ) {
 211                 wfProfileIn( __METHOD__ );
 212                 wfProfileIn( __METHOD__ . '-' . $this->name );
 213                 $status = $this->doDeleteInternal( $params );
 214                 $this->clearCache( array( $params['src'] ) );
 215                 $this->deleteFileCache( $params['src'] ); // persistent cache
 216                 wfProfileOut( __METHOD__ . '-' . $this->name );
 217                 wfProfileOut( __METHOD__ );
 218                 return $status;
 219         }
 220
 221         /**
 222          * @see FileBackendStore::deleteInternal()
 223          */
 224         abstract protected function doDeleteInternal( array $params );
 225
 226         /**
 227          * Move a file from one storage path to another in the backend.
 228          * Do not call this function from places outside FileBackend and FileOp.
 229          *
 230          * $params include:
 231          *   - src           : source storage path
 232          *   - dst           : destination storage path
 233          *   - overwrite     : overwrite any file that exists at the destination
 234          *   - disposition   : Content-Disposition header value for the destination
 235          *   - async         : Status will be returned immediately if supported.
 236          *                     If the status is OK, then its value field will be
 237          *                     set to a FileBackendStoreOpHandle object.
 238          *
 239          * @param $params Array
 240          * @return Status
 241          */
 242         final public function moveInternal( array $params ) {
 243                 wfProfileIn( __METHOD__ );
 244                 wfProfileIn( __METHOD__ . '-' . $this->name );
 245                 $status = $this->doMoveInternal( $params );
 246                 $this->clearCache( array( $params['src'], $params['dst'] ) );
 247                 $this->deleteFileCache( $params['src'] ); // persistent cache
 248                 if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
 249                         $this->deleteFileCache( $params['dst'] ); // persistent cache
 250                 }
 251                 wfProfileOut( __METHOD__ . '-' . $this->name );
 252                 wfProfileOut( __METHOD__ );
 253                 return $status;
 254         }
 255
 256         /**
 257          * @see FileBackendStore::moveInternal()
 258          * @return Status
 259          */
 260         protected function doMoveInternal( array $params ) {
 261                 unset( $params['async'] ); // two steps, won't work here :)
 262                 // Copy source to dest
 263                 $status = $this->copyInternal( $params );
 264                 if ( $status->isOK() ) {
 265                         // Delete source (only fails due to races or medium going down)
 266                         $status->merge( $this->deleteInternal( array( 'src' => $params['src'] ) ) );
 267                         $status->setResult( true, $status->value ); // ignore delete() errors
 268                 }
 269                 return $status;
 270         }
 271
 272         /**
 273          * No-op file operation that does nothing.
 274          * Do not call this function from places outside FileBackend and FileOp.
 275          *
 276          * @param $params Array
 277          * @return Status
 278          */
 279         final public function nullInternal( array $params ) {
 280                 return Status::newGood();
 281         }
 282
 283         /**
 284          * @see FileBackend::concatenate()
 285          * @return Status
 286          */
 287         final public function concatenate( array $params ) {
 288                 wfProfileIn( __METHOD__ );
 289                 wfProfileIn( __METHOD__ . '-' . $this->name );
 290                 $status = Status::newGood();
 291
 292                 // Try to lock the source files for the scope of this function
 293                 $scopeLockS = $this->getScopedFileLocks( $params['srcs'], LockManager::LOCK_UW, $status );
 294                 if ( $status->isOK() ) {
 295                         // Actually do the file concatenation...
 296                         $start_time = microtime( true );
 297                         $status->merge( $this->doConcatenate( $params ) );
 298                         $sec = microtime( true ) - $start_time;
 299                         if ( !$status->isOK() ) {
 300                                 wfDebugLog( 'FileOperation', get_class( $this ) . " failed to concatenate " .
 301                                         count( $params['srcs'] ) . " file(s) [$sec sec]" );
 302                         }
 303                 }
 304
 305                 wfProfileOut( __METHOD__ . '-' . $this->name );
 306                 wfProfileOut( __METHOD__ );
 307                 return $status;
 308         }
 309
 310         /**
 311          * @see FileBackendStore::concatenate()
 312          * @return Status
 313          */
 314         protected function doConcatenate( array $params ) {
 315                 $status = Status::newGood();
 316                 $tmpPath = $params['dst']; // convenience
 317
 318                 // Check that the specified temp file is valid...
 319                 wfSuppressWarnings();
 320                 $ok = ( is_file( $tmpPath ) && !filesize( $tmpPath ) );
 321                 wfRestoreWarnings();
 322                 if ( !$ok ) { // not present or not empty
 323                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 324                         return $status;
 325                 }
 326
 327                 // Build up the temp file using the source chunks (in order)...
 328                 $tmpHandle = fopen( $tmpPath, 'ab' );
 329                 if ( $tmpHandle === false ) {
 330                         $status->fatal( 'backend-fail-opentemp', $tmpPath );
 331                         return $status;
 332                 }
 333                 foreach ( $params['srcs'] as $virtualSource ) {
 334                         // Get a local FS version of the chunk
 335                         $tmpFile = $this->getLocalReference( array( 'src' => $virtualSource ) );
 336                         if ( !$tmpFile ) {
 337                                 $status->fatal( 'backend-fail-read', $virtualSource );
 338                                 return $status;
 339                         }
 340                         // Get a handle to the local FS version
 341                         $sourceHandle = fopen( $tmpFile->getPath(), 'r' );
 342                         if ( $sourceHandle === false ) {
 343                                 fclose( $tmpHandle );
 344                                 $status->fatal( 'backend-fail-read', $virtualSource );
 345                                 return $status;
 346                         }
 347                         // Append chunk to file (pass chunk size to avoid magic quotes)
 348                         if ( !stream_copy_to_stream( $sourceHandle, $tmpHandle ) ) {
 349                                 fclose( $sourceHandle );
 350                                 fclose( $tmpHandle );
 351                                 $status->fatal( 'backend-fail-writetemp', $tmpPath );
 352                                 return $status;
 353                         }
 354                         fclose( $sourceHandle );
 355                 }
 356                 if ( !fclose( $tmpHandle ) ) {
 357                         $status->fatal( 'backend-fail-closetemp', $tmpPath );
 358                         return $status;
 359                 }
 360
 361                 clearstatcache(); // temp file changed
 362
 363                 return $status;
 364         }
 365
 366         /**
 367          * @see FileBackend::doPrepare()
 368          * @return Status
 369          */
 370         final protected function doPrepare( array $params ) {
 371                 wfProfileIn( __METHOD__ );
 372                 wfProfileIn( __METHOD__ . '-' . $this->name );
 373
 374                 $status = Status::newGood();
 375                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 376                 if ( $dir === null ) {
 377                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 378                         wfProfileOut( __METHOD__ . '-' . $this->name );
 379                         wfProfileOut( __METHOD__ );
 380                         return $status; // invalid storage path
 381                 }
 382
 383                 if ( $shard !== null ) { // confined to a single container/shard
 384                         $status->merge( $this->doPrepareInternal( $fullCont, $dir, $params ) );
 385                 } else { // directory is on several shards
 386                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 387                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 388                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 389                                 $status->merge( $this->doPrepareInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 390                         }
 391                 }
 392
 393                 wfProfileOut( __METHOD__ . '-' . $this->name );
 394                 wfProfileOut( __METHOD__ );
 395                 return $status;
 396         }
 397
 398         /**
 399          * @see FileBackendStore::doPrepare()
 400          * @return Status
 401          */
 402         protected function doPrepareInternal( $container, $dir, array $params ) {
 403                 return Status::newGood();
 404         }
 405
 406         /**
 407          * @see FileBackend::doSecure()
 408          * @return Status
 409          */
 410         final protected function doSecure( array $params ) {
 411                 wfProfileIn( __METHOD__ );
 412                 wfProfileIn( __METHOD__ . '-' . $this->name );
 413                 $status = Status::newGood();
 414
 415                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 416                 if ( $dir === null ) {
 417                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 418                         wfProfileOut( __METHOD__ . '-' . $this->name );
 419                         wfProfileOut( __METHOD__ );
 420                         return $status; // invalid storage path
 421                 }
 422
 423                 if ( $shard !== null ) { // confined to a single container/shard
 424                         $status->merge( $this->doSecureInternal( $fullCont, $dir, $params ) );
 425                 } else { // directory is on several shards
 426                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 427                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 428                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 429                                 $status->merge( $this->doSecureInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 430                         }
 431                 }
 432
 433                 wfProfileOut( __METHOD__ . '-' . $this->name );
 434                 wfProfileOut( __METHOD__ );
 435                 return $status;
 436         }
 437
 438         /**
 439          * @see FileBackendStore::doSecure()
 440          * @return Status
 441          */
 442         protected function doSecureInternal( $container, $dir, array $params ) {
 443                 return Status::newGood();
 444         }
 445
 446         /**
 447          * @see FileBackend::doPublish()
 448          * @return Status
 449          */
 450         final protected function doPublish( array $params ) {
 451                 wfProfileIn( __METHOD__ );
 452                 wfProfileIn( __METHOD__ . '-' . $this->name );
 453                 $status = Status::newGood();
 454
 455                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 456                 if ( $dir === null ) {
 457                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 458                         wfProfileOut( __METHOD__ . '-' . $this->name );
 459                         wfProfileOut( __METHOD__ );
 460                         return $status; // invalid storage path
 461                 }
 462
 463                 if ( $shard !== null ) { // confined to a single container/shard
 464                         $status->merge( $this->doPublishInternal( $fullCont, $dir, $params ) );
 465                 } else { // directory is on several shards
 466                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 467                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 468                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 469                                 $status->merge( $this->doPublishInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 470                         }
 471                 }
 472
 473                 wfProfileOut( __METHOD__ . '-' . $this->name );
 474                 wfProfileOut( __METHOD__ );
 475                 return $status;
 476         }
 477
 478         /**
 479          * @see FileBackendStore::doPublish()
 480          * @return Status
 481          */
 482         protected function doPublishInternal( $container, $dir, array $params ) {
 483                 return Status::newGood();
 484         }
 485
 486         /**
 487          * @see FileBackend::doClean()
 488          * @return Status
 489          */
 490         final protected function doClean( array $params ) {
 491                 wfProfileIn( __METHOD__ );
 492                 wfProfileIn( __METHOD__ . '-' . $this->name );
 493                 $status = Status::newGood();
 494
 495                 // Recursive: first delete all empty subdirs recursively
 496                 if ( !empty( $params['recursive'] ) && !$this->directoriesAreVirtual() ) {
 497                         $subDirsRel = $this->getTopDirectoryList( array( 'dir' => $params['dir'] ) );
 498                         if ( $subDirsRel !== null ) { // no errors
 499                                 foreach ( $subDirsRel as $subDirRel ) {
 500                                         $subDir = $params['dir'] . "/{$subDirRel}"; // full path
 501                                         $status->merge( $this->doClean( array( 'dir' => $subDir ) + $params ) );
 502                                 }
 503                         }
 504                 }
 505
 506                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 507                 if ( $dir === null ) {
 508                         $status->fatal( 'backend-fail-invalidpath', $params['dir'] );
 509                         wfProfileOut( __METHOD__ . '-' . $this->name );
 510                         wfProfileOut( __METHOD__ );
 511                         return $status; // invalid storage path
 512                 }
 513
 514                 // Attempt to lock this directory...
 515                 $filesLockEx = array( $params['dir'] );
 516                 $scopedLockE = $this->getScopedFileLocks( $filesLockEx, LockManager::LOCK_EX, $status );
 517                 if ( !$status->isOK() ) {
 518                         wfProfileOut( __METHOD__ . '-' . $this->name );
 519                         wfProfileOut( __METHOD__ );
 520                         return $status; // abort
 521                 }
 522
 523                 if ( $shard !== null ) { // confined to a single container/shard
 524                         $status->merge( $this->doCleanInternal( $fullCont, $dir, $params ) );
 525                         $this->deleteContainerCache( $fullCont ); // purge cache
 526                 } else { // directory is on several shards
 527                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 528                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 529                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 530                                 $status->merge( $this->doCleanInternal( "{$fullCont}{$suffix}", $dir, $params ) );
 531                                 $this->deleteContainerCache( "{$fullCont}{$suffix}" ); // purge cache
 532                         }
 533                 }
 534
 535                 wfProfileOut( __METHOD__ . '-' . $this->name );
 536                 wfProfileOut( __METHOD__ );
 537                 return $status;
 538         }
 539
 540         /**
 541          * @see FileBackendStore::doClean()
 542          * @return Status
 543          */
 544         protected function doCleanInternal( $container, $dir, array $params ) {
 545                 return Status::newGood();
 546         }
 547
 548         /**
 549          * @see FileBackend::fileExists()
 550          * @return bool|null
 551          */
 552         final public function fileExists( array $params ) {
 553                 wfProfileIn( __METHOD__ );
 554                 wfProfileIn( __METHOD__ . '-' . $this->name );
 555                 $stat = $this->getFileStat( $params );
 556                 wfProfileOut( __METHOD__ . '-' . $this->name );
 557                 wfProfileOut( __METHOD__ );
 558                 return ( $stat === null ) ? null : (bool)$stat; // null => failure
 559         }
 560
 561         /**
 562          * @see FileBackend::getFileTimestamp()
 563          * @return bool
 564          */
 565         final public function getFileTimestamp( array $params ) {
 566                 wfProfileIn( __METHOD__ );
 567                 wfProfileIn( __METHOD__ . '-' . $this->name );
 568                 $stat = $this->getFileStat( $params );
 569                 wfProfileOut( __METHOD__ . '-' . $this->name );
 570                 wfProfileOut( __METHOD__ );
 571                 return $stat ? $stat['mtime'] : false;
 572         }
 573
 574         /**
 575          * @see FileBackend::getFileSize()
 576          * @return bool
 577          */
 578         final public function getFileSize( array $params ) {
 579                 wfProfileIn( __METHOD__ );
 580                 wfProfileIn( __METHOD__ . '-' . $this->name );
 581                 $stat = $this->getFileStat( $params );
 582                 wfProfileOut( __METHOD__ . '-' . $this->name );
 583                 wfProfileOut( __METHOD__ );
 584                 return $stat ? $stat['size'] : false;
 585         }
 586
 587         /**
 588          * @see FileBackend::getFileStat()
 589          * @return bool
 590          */
 591         final public function getFileStat( array $params ) {
 592                 $path = self::normalizeStoragePath( $params['src'] );
 593                 if ( $path === null ) {
 594                         return false; // invalid storage path
 595                 }
 596                 wfProfileIn( __METHOD__ );
 597                 wfProfileIn( __METHOD__ . '-' . $this->name );
 598                 $latest = !empty( $params['latest'] ); // use latest data?
 599                 if ( !$this->cheapCache->has( $path, 'stat' ) ) {
 600                         $this->primeFileCache( array( $path ) ); // check persistent cache
 601                 }
 602                 if ( $this->cheapCache->has( $path, 'stat' ) ) {
 603                         $stat = $this->cheapCache->get( $path, 'stat' );
 604                         // If we want the latest data, check that this cached
 605                         // value was in fact fetched with the latest available data.
 606                         if ( !$latest || $stat['latest'] ) {
 607                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 608                                 wfProfileOut( __METHOD__ );
 609                                 return $stat;
 610                         }
 611                 }
 612                 wfProfileIn( __METHOD__ . '-miss' );
 613                 wfProfileIn( __METHOD__ . '-miss-' . $this->name );
 614                 $stat = $this->doGetFileStat( $params );
 615                 wfProfileOut( __METHOD__ . '-miss-' . $this->name );
 616                 wfProfileOut( __METHOD__ . '-miss' );
 617                 if ( is_array( $stat ) ) { // don't cache negatives
 618                         $stat['latest'] = $latest;
 619                         $this->cheapCache->set( $path, 'stat', $stat );
 620                         $this->setFileCache( $path, $stat ); // update persistent cache
 621                         if ( isset( $stat['sha1'] ) ) { // some backends store SHA-1 as metadata
 622                                 $this->cheapCache->set( $path, 'sha1',
 623                                         array( 'hash' => $stat['sha1'], 'latest' => $latest ) );
 624                         }
 625                 } else {
 626                         wfDebug( __METHOD__ . ": File $path does not exist.\n" );
 627                 }
 628                 wfProfileOut( __METHOD__ . '-' . $this->name );
 629                 wfProfileOut( __METHOD__ );
 630                 return $stat;
 631         }
 632
 633         /**
 634          * @see FileBackendStore::getFileStat()
 635          */
 636         abstract protected function doGetFileStat( array $params );
 637
 638         /**
 639          * @see FileBackend::getFileContents()
 640          * @return bool|string
 641          */
 642         public function getFileContents( array $params ) {
 643                 wfProfileIn( __METHOD__ );
 644                 wfProfileIn( __METHOD__ . '-' . $this->name );
 645                 $tmpFile = $this->getLocalReference( $params );
 646                 if ( !$tmpFile ) {
 647                         wfProfileOut( __METHOD__ . '-' . $this->name );
 648                         wfProfileOut( __METHOD__ );
 649                         return false;
 650                 }
 651                 wfSuppressWarnings();
 652                 $data = file_get_contents( $tmpFile->getPath() );
 653                 wfRestoreWarnings();
 654                 wfProfileOut( __METHOD__ . '-' . $this->name );
 655                 wfProfileOut( __METHOD__ );
 656                 return $data;
 657         }
 658
 659         /**
 660          * @see FileBackend::getFileSha1Base36()
 661          * @return bool|string
 662          */
 663         final public function getFileSha1Base36( array $params ) {
 664                 $path = self::normalizeStoragePath( $params['src'] );
 665                 if ( $path === null ) {
 666                         return false; // invalid storage path
 667                 }
 668                 wfProfileIn( __METHOD__ );
 669                 wfProfileIn( __METHOD__ . '-' . $this->name );
 670                 $latest = !empty( $params['latest'] ); // use latest data?
 671                 if ( $this->cheapCache->has( $path, 'sha1' ) ) {
 672                         $stat = $this->cheapCache->get( $path, 'sha1' );
 673                         // If we want the latest data, check that this cached
 674                         // value was in fact fetched with the latest available data.
 675                         if ( !$latest || $stat['latest'] ) {
 676                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 677                                 wfProfileOut( __METHOD__ );
 678                                 return $stat['hash'];
 679                         }
 680                 }
 681                 wfProfileIn( __METHOD__ . '-miss' );
 682                 wfProfileIn( __METHOD__ . '-miss-' . $this->name );
 683                 $hash = $this->doGetFileSha1Base36( $params );
 684                 wfProfileOut( __METHOD__ . '-miss-' . $this->name );
 685                 wfProfileOut( __METHOD__ . '-miss' );
 686                 if ( $hash ) { // don't cache negatives
 687                         $this->cheapCache->set( $path, 'sha1',
 688                                 array( 'hash' => $hash, 'latest' => $latest ) );
 689                 }
 690                 wfProfileOut( __METHOD__ . '-' . $this->name );
 691                 wfProfileOut( __METHOD__ );
 692                 return $hash;
 693         }
 694
 695         /**
 696          * @see FileBackendStore::getFileSha1Base36()
 697          * @return bool|string
 698          */
 699         protected function doGetFileSha1Base36( array $params ) {
 700                 $fsFile = $this->getLocalReference( $params );
 701                 if ( !$fsFile ) {
 702                         return false;
 703                 } else {
 704                         return $fsFile->getSha1Base36();
 705                 }
 706         }
 707
 708         /**
 709          * @see FileBackend::getFileProps()
 710          * @return Array
 711          */
 712         final public function getFileProps( array $params ) {
 713                 wfProfileIn( __METHOD__ );
 714                 wfProfileIn( __METHOD__ . '-' . $this->name );
 715                 $fsFile = $this->getLocalReference( $params );
 716                 $props = $fsFile ? $fsFile->getProps() : FSFile::placeholderProps();
 717                 wfProfileOut( __METHOD__ . '-' . $this->name );
 718                 wfProfileOut( __METHOD__ );
 719                 return $props;
 720         }
 721
 722         /**
 723          * @see FileBackend::getLocalReference()
 724          * @return TempFSFile|null
 725          */
 726         public function getLocalReference( array $params ) {
 727                 $path = self::normalizeStoragePath( $params['src'] );
 728                 if ( $path === null ) {
 729                         return null; // invalid storage path
 730                 }
 731                 wfProfileIn( __METHOD__ );
 732                 wfProfileIn( __METHOD__ . '-' . $this->name );
 733                 $latest = !empty( $params['latest'] ); // use latest data?
 734                 if ( $this->expensiveCache->has( $path, 'localRef' ) ) {
 735                         $val = $this->expensiveCache->get( $path, 'localRef' );
 736                         // If we want the latest data, check that this cached
 737                         // value was in fact fetched with the latest available data.
 738                         if ( !$latest || $val['latest'] ) {
 739                                 wfProfileOut( __METHOD__ . '-' . $this->name );
 740                                 wfProfileOut( __METHOD__ );
 741                                 return $val['object'];
 742                         }
 743                 }
 744                 $tmpFile = $this->getLocalCopy( $params );
 745                 if ( $tmpFile ) { // don't cache negatives
 746                         $this->expensiveCache->set( $path, 'localRef',
 747                                 array( 'object' => $tmpFile, 'latest' => $latest ) );
 748                 }
 749                 wfProfileOut( __METHOD__ . '-' . $this->name );
 750                 wfProfileOut( __METHOD__ );
 751                 return $tmpFile;
 752         }
 753
 754         /**
 755          * @see FileBackend::streamFile()
 756          * @return Status
 757          */
 758         final public function streamFile( array $params ) {
 759                 wfProfileIn( __METHOD__ );
 760                 wfProfileIn( __METHOD__ . '-' . $this->name );
 761                 $status = Status::newGood();
 762
 763                 $info = $this->getFileStat( $params );
 764                 if ( !$info ) { // let StreamFile handle the 404
 765                         $status->fatal( 'backend-fail-notexists', $params['src'] );
 766                 }
 767
 768                 // Set output buffer and HTTP headers for stream
 769                 $extraHeaders = isset( $params['headers'] ) ? $params['headers'] : array();
 770                 $res = StreamFile::prepareForStream( $params['src'], $info, $extraHeaders );
 771                 if ( $res == StreamFile::NOT_MODIFIED ) {
 772                         // do nothing; client cache is up to date
 773                 } elseif ( $res == StreamFile::READY_STREAM ) {
 774                         wfProfileIn( __METHOD__ . '-send' );
 775                         wfProfileIn( __METHOD__ . '-send-' . $this->name );
 776                         $status = $this->doStreamFile( $params );
 777                         wfProfileOut( __METHOD__ . '-send-' . $this->name );
 778                         wfProfileOut( __METHOD__ . '-send' );
 779                 } else {
 780                         $status->fatal( 'backend-fail-stream', $params['src'] );
 781                 }
 782
 783                 wfProfileOut( __METHOD__ . '-' . $this->name );
 784                 wfProfileOut( __METHOD__ );
 785                 return $status;
 786         }
 787
 788         /**
 789          * @see FileBackendStore::streamFile()
 790          * @return Status
 791          */
 792         protected function doStreamFile( array $params ) {
 793                 $status = Status::newGood();
 794
 795                 $fsFile = $this->getLocalReference( $params );
 796                 if ( !$fsFile ) {
 797                         $status->fatal( 'backend-fail-stream', $params['src'] );
 798                 } elseif ( !readfile( $fsFile->getPath() ) ) {
 799                         $status->fatal( 'backend-fail-stream', $params['src'] );
 800                 }
 801
 802                 return $status;
 803         }
 804
 805         /**
 806          * @see FileBackend::directoryExists()
 807          * @return bool|null
 808          */
 809         final public function directoryExists( array $params ) {
 810                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 811                 if ( $dir === null ) {
 812                         return false; // invalid storage path
 813                 }
 814                 if ( $shard !== null ) { // confined to a single container/shard
 815                         return $this->doDirectoryExists( $fullCont, $dir, $params );
 816                 } else { // directory is on several shards
 817                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 818                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 819                         $res = false; // response
 820                         foreach ( $this->getContainerSuffixes( $shortCont ) as $suffix ) {
 821                                 $exists = $this->doDirectoryExists( "{$fullCont}{$suffix}", $dir, $params );
 822                                 if ( $exists ) {
 823                                         $res = true;
 824                                         break; // found one!
 825                                 } elseif ( $exists === null ) { // error?
 826                                         $res = null; // if we don't find anything, it is indeterminate
 827                                 }
 828                         }
 829                         return $res;
 830                 }
 831         }
 832
 833         /**
 834          * @see FileBackendStore::directoryExists()
 835          *
 836          * @param $container string Resolved container name
 837          * @param $dir string Resolved path relative to container
 838          * @param $params Array
 839          * @return bool|null
 840          */
 841         abstract protected function doDirectoryExists( $container, $dir, array $params );
 842
 843         /**
 844          * @see FileBackend::getDirectoryList()
 845          * @return Traversable|Array|null Returns null on failure
 846          */
 847         final public function getDirectoryList( array $params ) {
 848                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 849                 if ( $dir === null ) { // invalid storage path
 850                         return null;
 851                 }
 852                 if ( $shard !== null ) {
 853                         // File listing is confined to a single container/shard
 854                         return $this->getDirectoryListInternal( $fullCont, $dir, $params );
 855                 } else {
 856                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 857                         // File listing spans multiple containers/shards
 858                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 859                         return new FileBackendStoreShardDirIterator( $this,
 860                                 $fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
 861                 }
 862         }
 863
 864         /**
 865          * Do not call this function from places outside FileBackend
 866          *
 867          * @see FileBackendStore::getDirectoryList()
 868          *
 869          * @param $container string Resolved container name
 870          * @param $dir string Resolved path relative to container
 871          * @param $params Array
 872          * @return Traversable|Array|null Returns null on failure
 873          */
 874         abstract public function getDirectoryListInternal( $container, $dir, array $params );
 875
 876         /**
 877          * @see FileBackend::getFileList()
 878          * @return Traversable|Array|null Returns null on failure
 879          */
 880         final public function getFileList( array $params ) {
 881                 list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
 882                 if ( $dir === null ) { // invalid storage path
 883                         return null;
 884                 }
 885                 if ( $shard !== null ) {
 886                         // File listing is confined to a single container/shard
 887                         return $this->getFileListInternal( $fullCont, $dir, $params );
 888                 } else {
 889                         wfDebug( __METHOD__ . ": iterating over all container shards.\n" );
 890                         // File listing spans multiple containers/shards
 891                         list( $b, $shortCont, $r ) = self::splitStoragePath( $params['dir'] );
 892                         return new FileBackendStoreShardFileIterator( $this,
 893                                 $fullCont, $dir, $this->getContainerSuffixes( $shortCont ), $params );
 894                 }
 895         }
 896
 897         /**
 898          * Do not call this function from places outside FileBackend
 899          *
 900          * @see FileBackendStore::getFileList()
 901          *
 902          * @param $container string Resolved container name
 903          * @param $dir string Resolved path relative to container
 904          * @param $params Array
 905          * @return Traversable|Array|null Returns null on failure
 906          */
 907         abstract public function getFileListInternal( $container, $dir, array $params );
 908
 909         /**
 910          * Return a list of FileOp objects from a list of operations.
 911          * Do not call this function from places outside FileBackend.
 912          *
 913          * The result must have the same number of items as the input.
 914          * An exception is thrown if an unsupported operation is requested.
 915          *
 916          * @param $ops Array Same format as doOperations()
 917          * @return Array List of FileOp objects
 918          * @throws MWException
 919          */
 920         final public function getOperationsInternal( array $ops ) {
 921                 $supportedOps = array(
 922                         'store'       => 'StoreFileOp',
 923                         'copy'        => 'CopyFileOp',
 924                         'move'        => 'MoveFileOp',
 925                         'delete'      => 'DeleteFileOp',
 926                         'create'      => 'CreateFileOp',
 927                         'null'        => 'NullFileOp'
 928                 );
 929
 930                 $performOps = array(); // array of FileOp objects
 931                 // Build up ordered array of FileOps...
 932                 foreach ( $ops as $operation ) {
 933                         $opName = $operation['op'];
 934                         if ( isset( $supportedOps[$opName] ) ) {
 935                                 $class = $supportedOps[$opName];
 936                                 // Get params for this operation
 937                                 $params = $operation;
 938                                 // Append the FileOp class
 939                                 $performOps[] = new $class( $this, $params );
 940                         } else {
 941                                 throw new MWException( "Operation '$opName' is not supported." );
 942                         }
 943                 }
 944
 945                 return $performOps;
 946         }
 947
 948         /**
 949          * Get a list of storage paths to lock for a list of operations
 950          * Returns an array with 'sh' (shared) and 'ex' (exclusive) keys,
 951          * each corresponding to a list of storage paths to be locked.
 952          *
 953          * @param $performOps Array List of FileOp objects
 954          * @return Array ('sh' => list of paths, 'ex' => list of paths)
 955          */
 956         final public function getPathsToLockForOpsInternal( array $performOps ) {
 957                 // Build up a list of files to lock...
 958                 $paths = array( 'sh' => array(), 'ex' => array() );
 959                 foreach ( $performOps as $fileOp ) {
 960                         $paths['sh'] = array_merge( $paths['sh'], $fileOp->storagePathsRead() );
 961                         $paths['ex'] = array_merge( $paths['ex'], $fileOp->storagePathsChanged() );
 962                 }
 963                 // Optimization: if doing an EX lock anyway, don't also set an SH one
 964                 $paths['sh'] = array_diff( $paths['sh'], $paths['ex'] );
 965                 // Get a shared lock on the parent directory of each path changed
 966                 $paths['sh'] = array_merge( $paths['sh'], array_map( 'dirname', $paths['ex'] ) );
 967
 968                 return $paths;
 969         }
 970
 971         /**
 972          * @see FileBackend::getScopedLocksForOps()
 973          * @return Array
 974          */
 975         public function getScopedLocksForOps( array $ops, Status $status ) {
 976                 $paths = $this->getPathsToLockForOpsInternal( $this->getOperationsInternal( $ops ) );
 977                 return array(
 978                         $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status ),
 979                         $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status )
 980                 );
 981         }
 982
 983         /**
 984          * @see FileBackend::doOperationsInternal()
 985          * @return Status
 986          */
 987         final protected function doOperationsInternal( array $ops, array $opts ) {
 988                 wfProfileIn( __METHOD__ );
 989                 wfProfileIn( __METHOD__ . '-' . $this->name );
 990                 $status = Status::newGood();
 991
 992                 // Build up a list of FileOps...
 993                 $performOps = $this->getOperationsInternal( $ops );
 994
 995                 // Acquire any locks as needed...
 996                 if ( empty( $opts['nonLocking'] ) ) {
 997                         // Build up a list of files to lock...
 998                         $paths = $this->getPathsToLockForOpsInternal( $performOps );
 999                         // Try to lock those files for the scope of this function...
1000                         $scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status );
1001                         $scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status );
1002                         if ( !$status->isOK() ) {
1003                                 wfProfileOut( __METHOD__ . '-' . $this->name );
1004                                 wfProfileOut( __METHOD__ );
1005                                 return $status; // abort
1006                         }
1007                 }
1008
1009                 // Clear any file cache entries (after locks acquired)
1010                 if ( empty( $opts['preserveCache'] ) ) {
1011                         $this->clearCache();
1012                 }
1013
1014                 // Load from the persistent file and container caches
1015                 $this->primeFileCache( $performOps );
1016                 $this->primeContainerCache( $performOps );
1017
1018                 // Actually attempt the operation batch...
1019                 $subStatus = FileOpBatch::attempt( $performOps, $opts, $this->fileJournal );
1020
1021                 // Merge errors into status fields
1022                 $status->merge( $subStatus );
1023                 $status->success = $subStatus->success; // not done in merge()
1024
1025                 wfProfileOut( __METHOD__ . '-' . $this->name );
1026                 wfProfileOut( __METHOD__ );
1027                 return $status;
1028         }
1029
1030         /**
1031          * @see FileBackend::doQuickOperationsInternal()
1032          * @return Status
1033          * @throws MWException
1034          */
1035         final protected function doQuickOperationsInternal( array $ops ) {
1036                 wfProfileIn( __METHOD__ );
1037                 wfProfileIn( __METHOD__ . '-' . $this->name );
1038                 $status = Status::newGood();
1039
1040                 $supportedOps = array( 'create', 'store', 'copy', 'move', 'delete', 'null' );
1041                 $async = ( $this->parallelize === 'implicit' );
1042                 $maxConcurrency = $this->concurrency; // throttle
1043
1044                 $statuses = array(); // array of (index => Status)
1045                 $fileOpHandles = array(); // list of (index => handle) arrays
1046                 $curFileOpHandles = array(); // current handle batch
1047                 // Perform the sync-only ops and build up op handles for the async ops...
1048                 foreach ( $ops as $index => $params ) {
1049                         if ( !in_array( $params['op'], $supportedOps ) ) {
1050                                 wfProfileOut( __METHOD__ . '-' . $this->name );
1051                                 wfProfileOut( __METHOD__ );
1052                                 throw new MWException( "Operation '{$params['op']}' is not supported." );
1053                         }
1054                         $method = $params['op'] . 'Internal'; // e.g. "storeInternal"
1055                         $subStatus = $this->$method( array( 'async' => $async ) + $params );
1056                         if ( $subStatus->value instanceof FileBackendStoreOpHandle ) { // async
1057                                 if ( count( $curFileOpHandles ) >= $maxConcurrency ) {
1058                                         $fileOpHandles[] = $curFileOpHandles; // push this batch
1059                                         $curFileOpHandles = array();
1060                                 }
1061                                 $curFileOpHandles[$index] = $subStatus->value; // keep index
1062                         } else { // error or completed
1063                                 $statuses[$index] = $subStatus; // keep index
1064                         }
1065                 }
1066                 if ( count( $curFileOpHandles ) ) {
1067                         $fileOpHandles[] = $curFileOpHandles; // last batch
1068                 }
1069                 // Do all the async ops that can be done concurrently...
1070                 foreach ( $fileOpHandles as $fileHandleBatch ) {
1071                         $statuses = $statuses + $this->executeOpHandlesInternal( $fileHandleBatch );
1072                 }
1073                 // Marshall and merge all the responses...
1074                 foreach ( $statuses as $index => $subStatus ) {
1075                         $status->merge( $subStatus );
1076                         if ( $subStatus->isOK() ) {
1077                                 $status->success[$index] = true;
1078                                 ++$status->successCount;
1079                         } else {
1080                                 $status->success[$index] = false;
1081                                 ++$status->failCount;
1082                         }
1083                 }
1084
1085                 wfProfileOut( __METHOD__ . '-' . $this->name );
1086                 wfProfileOut( __METHOD__ );
1087                 return $status;
1088         }
1089
1090         /**
1091          * Execute a list of FileBackendStoreOpHandle handles in parallel.
1092          * The resulting Status object fields will correspond
1093          * to the order in which the handles where given.
1094          *
1095          * @param $handles Array List of FileBackendStoreOpHandle objects
1096          * @return Array Map of Status objects
1097          * @throws MWException
1098          */
1099         final public function executeOpHandlesInternal( array $fileOpHandles ) {
1100                 wfProfileIn( __METHOD__ );
1101                 wfProfileIn( __METHOD__ . '-' . $this->name );
1102                 foreach ( $fileOpHandles as $fileOpHandle ) {
1103                         if ( !( $fileOpHandle instanceof FileBackendStoreOpHandle ) ) {
1104                                 throw new MWException( "Given a non-FileBackendStoreOpHandle object." );
1105                         } elseif ( $fileOpHandle->backend->getName() !== $this->getName() ) {
1106                                 throw new MWException( "Given a FileBackendStoreOpHandle for the wrong backend." );
1107                         }
1108                 }
1109                 $res = $this->doExecuteOpHandlesInternal( $fileOpHandles );
1110                 foreach ( $fileOpHandles as $fileOpHandle ) {
1111                         $fileOpHandle->closeResources();
1112                 }
1113                 wfProfileOut( __METHOD__ . '-' . $this->name );
1114                 wfProfileOut( __METHOD__ );
1115                 return $res;
1116         }
1117
1118         /**
1119          * @see FileBackendStore::executeOpHandlesInternal()
1120          * @return Array List of corresponding Status objects
1121          */
1122         protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
1123                 foreach ( $fileOpHandles as $fileOpHandle ) { // OK if empty
1124                         throw new MWException( "This backend supports no asynchronous operations." );
1125                 }
1126                 return array();
1127         }
1128
1129         /**
1130          * @see FileBackend::preloadCache()
1131          */
1132         final public function preloadCache( array $paths ) {
1133                 $fullConts = array(); // full container names
1134                 foreach ( $paths as $path ) {
1135                         list( $fullCont, $r, $s ) = $this->resolveStoragePath( $path );
1136                         $fullConts[] = $fullCont;
1137                 }
1138                 // Load from the persistent file and container caches
1139                 $this->primeContainerCache( $fullConts );
1140                 $this->primeFileCache( $paths );
1141         }
1142
1143         /**
1144          * @see FileBackend::clearCache()
1145          */
1146         final public function clearCache( array $paths = null ) {
1147                 if ( is_array( $paths ) ) {
1148                         $paths = array_map( 'FileBackend::normalizeStoragePath', $paths );
1149                         $paths = array_filter( $paths, 'strlen' ); // remove nulls
1150                 }
1151                 if ( $paths === null ) {
1152                         $this->cheapCache->clear();
1153                         $this->expensiveCache->clear();
1154                 } else {
1155                         foreach ( $paths as $path ) {
1156                                 $this->cheapCache->clear( $path );
1157                                 $this->expensiveCache->clear( $path );
1158                         }
1159                 }
1160                 $this->doClearCache( $paths );
1161         }
1162
1163         /**
1164          * Clears any additional stat caches for storage paths
1165          *
1166          * @see FileBackend::clearCache()
1167          *
1168          * @param $paths Array Storage paths (optional)
1169          * @return void
1170          */
1171         protected function doClearCache( array $paths = null ) {}
1172
1173         /**
1174          * Is this a key/value store where directories are just virtual?
1175          * Virtual directories exists in so much as files exists that are
1176          * prefixed with the directory path followed by a forward slash.
1177          *
1178          * @return bool
1179          */
1180         abstract protected function directoriesAreVirtual();
1181
1182         /**
1183          * Check if a container name is valid.
1184          * This checks for for length and illegal characters.
1185          *
1186          * @param $container string
1187          * @return bool
1188          */
1189         final protected static function isValidContainerName( $container ) {
1190                 // This accounts for Swift and S3 restrictions while leaving room
1191                 // for things like '.xxx' (hex shard chars) or '.seg' (segments).
1192                 // This disallows directory separators or traversal characters.
1193                 // Note that matching strings URL encode to the same string;
1194                 // in Swift, the length restriction is *after* URL encoding.
1195                 return preg_match( '/^[a-z0-9][a-z0-9-_]{0,199}$/i', $container );
1196         }
1197
1198         /**
1199          * Splits a storage path into an internal container name,
1200          * an internal relative file name, and a container shard suffix.
1201          * Any shard suffix is already appended to the internal container name.
1202          * This also checks that the storage path is valid and within this backend.
1203          *
1204          * If the container is sharded but a suffix could not be determined,
1205          * this means that the path can only refer to a directory and can only
1206          * be scanned by looking in all the container shards.
1207          *
1208          * @param $storagePath string
1209          * @return Array (container, path, container suffix) or (null, null, null) if invalid
1210          */
1211         final protected function resolveStoragePath( $storagePath ) {
1212                 list( $backend, $container, $relPath ) = self::splitStoragePath( $storagePath );
1213                 if ( $backend === $this->name ) { // must be for this backend
1214                         $relPath = self::normalizeContainerPath( $relPath );
1215                         if ( $relPath !== null ) {
1216                                 // Get shard for the normalized path if this container is sharded
1217                                 $cShard = $this->getContainerShard( $container, $relPath );
1218                                 // Validate and sanitize the relative path (backend-specific)
1219                                 $relPath = $this->resolveContainerPath( $container, $relPath );
1220                                 if ( $relPath !== null ) {
1221                                         // Prepend any wiki ID prefix to the container name
1222                                         $container = $this->fullContainerName( $container );
1223                                         if ( self::isValidContainerName( $container ) ) {
1224                                                 // Validate and sanitize the container name (backend-specific)
1225                                                 $container = $this->resolveContainerName( "{$container}{$cShard}" );
1226                                                 if ( $container !== null ) {
1227                                                         return array( $container, $relPath, $cShard );
1228                                                 }
1229                                         }
1230                                 }
1231                         }
1232                 }
1233                 return array( null, null, null );
1234         }
1235
1236         /**
1237          * Like resolveStoragePath() except null values are returned if
1238          * the container is sharded and the shard could not be determined.
1239          *
1240          * @see FileBackendStore::resolveStoragePath()
1241          *
1242          * @param $storagePath string
1243          * @return Array (container, path) or (null, null) if invalid
1244          */
1245         final protected function resolveStoragePathReal( $storagePath ) {
1246                 list( $container, $relPath, $cShard ) = $this->resolveStoragePath( $storagePath );
1247                 if ( $cShard !== null ) {
1248                         return array( $container, $relPath );
1249                 }
1250                 return array( null, null );
1251         }
1252
1253         /**
1254          * Get the container name shard suffix for a given path.
1255          * Any empty suffix means the container is not sharded.
1256          *
1257          * @param $container string Container name
1258          * @param $relPath string Storage path relative to the container
1259          * @return string|null Returns null if shard could not be determined
1260          */
1261         final protected function getContainerShard( $container, $relPath ) {
1262                 list( $levels, $base, $repeat ) = $this->getContainerHashLevels( $container );
1263                 if ( $levels == 1 || $levels == 2 ) {
1264                         // Hash characters are either base 16 or 36
1265                         $char = ( $base == 36 ) ? '[0-9a-z]' : '[0-9a-f]';
1266                         // Get a regex that represents the shard portion of paths.
1267                         // The concatenation of the captures gives us the shard.
1268                         if ( $levels === 1 ) { // 16 or 36 shards per container
1269                                 $hashDirRegex = '(' . $char . ')';
1270                         } else { // 256 or 1296 shards per container
1271                                 if ( $repeat ) { // verbose hash dir format (e.g. "a/ab/abc")
1272                                         $hashDirRegex = $char . '/(' . $char . '{2})';
1273                                 } else { // short hash dir format (e.g. "a/b/c")
1274                                         $hashDirRegex = '(' . $char . ')/(' . $char . ')';
1275                                 }
1276                         }
1277                         // Allow certain directories to be above the hash dirs so as
1278                         // to work with FileRepo (e.g. "archive/a/ab" or "temp/a/ab").
1279                         // They must be 2+ chars to avoid any hash directory ambiguity.
1280                         $m = array();
1281                         if ( preg_match( "!^(?:[^/]{2,}/)*$hashDirRegex(?:/|$)!", $relPath, $m ) ) {
1282                                 return '.' . implode( '', array_slice( $m, 1 ) );
1283                         }
1284                         return null; // failed to match
1285                 }
1286                 return ''; // no sharding
1287         }
1288
1289         /**
1290          * Check if a storage path maps to a single shard.
1291          * Container dirs like "a", where the container shards on "x/xy",
1292          * can reside on several shards. Such paths are tricky to handle.
1293          *
1294          * @param $storagePath string Storage path
1295          * @return bool
1296          */
1297         final public function isSingleShardPathInternal( $storagePath ) {
1298                 list( $c, $r, $shard ) = $this->resolveStoragePath( $storagePath );
1299                 return ( $shard !== null );
1300         }
1301
1302         /**
1303          * Get the sharding config for a container.
1304          * If greater than 0, then all file storage paths within
1305          * the container are required to be hashed accordingly.
1306          *
1307          * @param $container string
1308          * @return Array (integer levels, integer base, repeat flag) or (0, 0, false)
1309          */
1310         final protected function getContainerHashLevels( $container ) {
1311                 if ( isset( $this->shardViaHashLevels[$container] ) ) {
1312                         $config = $this->shardViaHashLevels[$container];
1313                         $hashLevels = (int)$config['levels'];
1314                         if ( $hashLevels == 1 || $hashLevels == 2 ) {
1315                                 $hashBase = (int)$config['base'];
1316                                 if ( $hashBase == 16 || $hashBase == 36 ) {
1317                                         return array( $hashLevels, $hashBase, $config['repeat'] );
1318                                 }
1319                         }
1320                 }
1321                 return array( 0, 0, false ); // no sharding
1322         }
1323
1324         /**
1325          * Get a list of full container shard suffixes for a container
1326          *
1327          * @param $container string
1328          * @return Array
1329          */
1330         final protected function getContainerSuffixes( $container ) {
1331                 $shards = array();
1332                 list( $digits, $base ) = $this->getContainerHashLevels( $container );
1333                 if ( $digits > 0 ) {
1334                         $numShards = pow( $base, $digits );
1335                         for ( $index = 0; $index < $numShards; $index++ ) {
1336                                 $shards[] = '.' . wfBaseConvert( $index, 10, $base, $digits );
1337                         }
1338                 }
1339                 return $shards;
1340         }
1341
1342         /**
1343          * Get the full container name, including the wiki ID prefix
1344          *
1345          * @param $container string
1346          * @return string
1347          */
1348         final protected function fullContainerName( $container ) {
1349                 if ( $this->wikiId != '' ) {
1350                         return "{$this->wikiId}-$container";
1351                 } else {
1352                         return $container;
1353                 }
1354         }
1355
1356         /**
1357          * Resolve a container name, checking if it's allowed by the backend.
1358          * This is intended for internal use, such as encoding illegal chars.
1359          * Subclasses can override this to be more restrictive.
1360          *
1361          * @param $container string
1362          * @return string|null
1363          */
1364         protected function resolveContainerName( $container ) {
1365                 return $container;
1366         }
1367
1368         /**
1369          * Resolve a relative storage path, checking if it's allowed by the backend.
1370          * This is intended for internal use, such as encoding illegal chars or perhaps
1371          * getting absolute paths (e.g. FS based backends). Note that the relative path
1372          * may be the empty string (e.g. the path is simply to the container).
1373          *
1374          * @param $container string Container name
1375          * @param $relStoragePath string Storage path relative to the container
1376          * @return string|null Path or null if not valid
1377          */
1378         protected function resolveContainerPath( $container, $relStoragePath ) {
1379                 return $relStoragePath;
1380         }
1381
1382         /**
1383          * Get the cache key for a container
1384          *
1385          * @param $container string Resolved container name
1386          * @return string
1387          */
1388         private function containerCacheKey( $container ) {
1389                 return wfMemcKey( 'backend', $this->getName(), 'container', $container );
1390         }
1391
1392         /**
1393          * Set the cached info for a container
1394          *
1395          * @param $container string Resolved container name
1396          * @param $val mixed Information to cache
1397          */
1398         final protected function setContainerCache( $container, $val ) {
1399                 $this->memCache->add( $this->containerCacheKey( $container ), $val, 14*86400 );
1400         }
1401
1402         /**
1403          * Delete the cached info for a container.
1404          * The cache key is salted for a while to prevent race conditions.
1405          *
1406          * @param $container string Resolved container name
1407          */
1408         final protected function deleteContainerCache( $container ) {
1409                 if ( !$this->memCache->set( $this->containerCacheKey( $container ), 'PURGED', 300 ) ) {
1410                         trigger_error( "Unable to delete stat cache for container $container." );
1411                 }
1412         }
1413
1414         /**
1415          * Do a batch lookup from cache for container stats for all containers
1416          * used in a list of container names, storage paths, or FileOp objects.
1417          *
1418          * @param $items Array
1419          * @return void
1420          */
1421         final protected function primeContainerCache( array $items ) {
1422                 wfProfileIn( __METHOD__ );
1423                 wfProfileIn( __METHOD__ . '-' . $this->name );
1424
1425                 $paths = array(); // list of storage paths
1426                 $contNames = array(); // (cache key => resolved container name)
1427                 // Get all the paths/containers from the items...
1428                 foreach ( $items as $item ) {
1429                         if ( $item instanceof FileOp ) {
1430                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1431                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1432                         } elseif ( self::isStoragePath( $item ) ) {
1433                                 $paths[] = $item;
1434                         } elseif ( is_string( $item ) ) { // full container name
1435                                 $contNames[$this->containerCacheKey( $item )] = $item;
1436                         }
1437                 }
1438                 // Get all the corresponding cache keys for paths...
1439                 foreach ( $paths as $path ) {
1440                         list( $fullCont, $r, $s ) = $this->resolveStoragePath( $path );
1441                         if ( $fullCont !== null ) { // valid path for this backend
1442                                 $contNames[$this->containerCacheKey( $fullCont )] = $fullCont;
1443                         }
1444                 }
1445
1446                 $contInfo = array(); // (resolved container name => cache value)
1447                 // Get all cache entries for these container cache keys...
1448                 $values = $this->memCache->getMulti( array_keys( $contNames ) );
1449                 foreach ( $values as $cacheKey => $val ) {
1450                         $contInfo[$contNames[$cacheKey]] = $val;
1451                 }
1452
1453                 // Populate the container process cache for the backend...
1454                 $this->doPrimeContainerCache( array_filter( $contInfo, 'is_array' ) );
1455
1456                 wfProfileOut( __METHOD__ . '-' . $this->name );
1457                 wfProfileOut( __METHOD__ );
1458         }
1459
1460         /**
1461          * Fill the backend-specific process cache given an array of
1462          * resolved container names and their corresponding cached info.
1463          * Only containers that actually exist should appear in the map.
1464          *
1465          * @param $containerInfo Array Map of resolved container names to cached info
1466          * @return void
1467          */
1468         protected function doPrimeContainerCache( array $containerInfo ) {}
1469
1470         /**
1471          * Get the cache key for a file path
1472          *
1473          * @param $path string Storage path
1474          * @return string
1475          */
1476         private function fileCacheKey( $path ) {
1477                 return wfMemcKey( 'backend', $this->getName(), 'file', sha1( $path ) );
1478         }
1479
1480         /**
1481          * Set the cached stat info for a file path.
1482          * Negatives (404s) are not cached. By not caching negatives, we can skip cache
1483          * salting for the case when a file is created at a path were there was none before.
1484          *
1485          * @param $path string Storage path
1486          * @param $val mixed Information to cache
1487          */
1488         final protected function setFileCache( $path, $val ) {
1489                 $this->memCache->add( $this->fileCacheKey( $path ), $val, 7*86400 );
1490         }
1491
1492         /**
1493          * Delete the cached stat info for a file path.
1494          * The cache key is salted for a while to prevent race conditions.
1495          *
1496          * @param $path string Storage path
1497          */
1498         final protected function deleteFileCache( $path ) {
1499                 if ( !$this->memCache->set( $this->fileCacheKey( $path ), 'PURGED', 300 ) ) {
1500                         trigger_error( "Unable to delete stat cache for file $path." );
1501                 }
1502         }
1503
1504         /**
1505          * Do a batch lookup from cache for file stats for all paths
1506          * used in a list of storage paths or FileOp objects.
1507          *
1508          * @param $items Array List of storage paths or FileOps
1509          * @return void
1510          */
1511         final protected function primeFileCache( array $items ) {
1512                 wfProfileIn( __METHOD__ );
1513                 wfProfileIn( __METHOD__ . '-' . $this->name );
1514
1515                 $paths = array(); // list of storage paths
1516                 $pathNames = array(); // (cache key => storage path)
1517                 // Get all the paths/containers from the items...
1518                 foreach ( $items as $item ) {
1519                         if ( $item instanceof FileOp ) {
1520                                 $paths = array_merge( $paths, $item->storagePathsRead() );
1521                                 $paths = array_merge( $paths, $item->storagePathsChanged() );
1522                         } elseif ( self::isStoragePath( $item ) ) {
1523                                 $paths[] = $item;
1524                         }
1525                 }
1526                 // Get all the corresponding cache keys for paths...
1527                 foreach ( $paths as $path ) {
1528                         list( $cont, $rel, $s ) = $this->resolveStoragePath( $path );
1529                         if ( $rel !== null ) { // valid path for this backend
1530                                 $pathNames[$this->fileCacheKey( $path )] = $path;
1531                         }
1532                 }
1533                 // Get all cache entries for these container cache keys...
1534                 $values = $this->memCache->getMulti( array_keys( $pathNames ) );
1535                 foreach ( $values as $cacheKey => $val ) {
1536                         if ( is_array( $val ) ) {
1537                                 $path = $pathNames[$cacheKey];
1538                                 $this->cheapCache->set( $path, 'stat', $val );
1539                                 if ( isset( $val['sha1'] ) ) { // some backends store SHA-1 as metadata
1540                                         $this->cheapCache->set( $path, 'sha1',
1541                                                 array( 'hash' => $val['sha1'], 'latest' => $val['latest'] ) );
1542                                 }
1543                         }
1544                 }
1545
1546                 wfProfileOut( __METHOD__ . '-' . $this->name );
1547                 wfProfileOut( __METHOD__ );
1548         }
1549 }
1550
1551 /**
1552  * FileBackendStore helper class for performing asynchronous file operations.
1553  *
1554  * For example, calling FileBackendStore::createInternal() with the "async"
1555  * param flag may result in a Status that contains this object as a value.
1556  * This class is largely backend-specific and is mostly just "magic" to be
1557  * passed to FileBackendStore::executeOpHandlesInternal().
1558  */
1559 abstract class FileBackendStoreOpHandle {
1560         /** @var Array */
1561         public $params = array(); // params to caller functions
1562         /** @var FileBackendStore */
1563         public $backend;
1564         /** @var Array */
1565         public $resourcesToClose = array();
1566
1567         public $call; // string; name that identifies the function called
1568
1569         /**
1570          * Close all open file handles
1571          *
1572          * @return void
1573          */
1574         public function closeResources() {
1575                 array_map( 'fclose', $this->resourcesToClose );
1576         }
1577 }
1578
1579 /**
1580  * FileBackendStore helper function to handle listings that span container shards.
1581  * Do not use this class from places outside of FileBackendStore.
1582  *
1583  * @ingroup FileBackend
1584  */
1585 abstract class FileBackendStoreShardListIterator implements Iterator {
1586         /** @var FileBackendStore */
1587         protected $backend;
1588         /** @var Array */
1589         protected $params;
1590         /** @var Array */
1591         protected $shardSuffixes;
1592         protected $container; // string; full container name
1593         protected $directory; // string; resolved relative path
1594
1595         /** @var Traversable */
1596         protected $iter;
1597         protected $curShard = 0; // integer
1598         protected $pos = 0; // integer
1599
1600         /** @var Array */
1601         protected $multiShardPaths = array(); // (rel path => 1)
1602
1603         /**
1604          * @param $backend FileBackendStore
1605          * @param $container string Full storage container name
1606          * @param $dir string Storage directory relative to container
1607          * @param $suffixes Array List of container shard suffixes
1608          * @param $params Array
1609          */
1610         public function __construct(
1611                 FileBackendStore $backend, $container, $dir, array $suffixes, array $params
1612         ) {
1613                 $this->backend = $backend;
1614                 $this->container = $container;
1615                 $this->directory = $dir;
1616                 $this->shardSuffixes = $suffixes;
1617                 $this->params = $params;
1618         }
1619
1620         /**
1621          * @see Iterator::key()
1622          * @return integer
1623          */
1624         public function key() {
1625                 return $this->pos;
1626         }
1627
1628         /**
1629          * @see Iterator::valid()
1630          * @return bool
1631          */
1632         public function valid() {
1633                 if ( $this->iter instanceof Iterator ) {
1634                         return $this->iter->valid();
1635                 } elseif ( is_array( $this->iter ) ) {
1636                         return ( current( $this->iter ) !== false ); // no paths can have this value
1637                 }
1638                 return false; // some failure?
1639         }
1640
1641         /**
1642          * @see Iterator::current()
1643          * @return string|bool String or false
1644          */
1645         public function current() {
1646                 return ( $this->iter instanceof Iterator )
1647                         ? $this->iter->current()
1648                         : current( $this->iter );
1649         }
1650
1651         /**
1652          * @see Iterator::next()
1653          * @return void
1654          */
1655         public function next() {
1656                 ++$this->pos;
1657                 ( $this->iter instanceof Iterator ) ? $this->iter->next() : next( $this->iter );
1658                 do {
1659                         $continue = false; // keep scanning shards?
1660                         $this->filterViaNext(); // filter out duplicates
1661                         // Find the next non-empty shard if no elements are left
1662                         if ( !$this->valid() ) {
1663                                 $this->nextShardIteratorIfNotValid();
1664                                 $continue = $this->valid(); // re-filter unless we ran out of shards
1665                         }
1666                 } while ( $continue );
1667         }
1668
1669         /**
1670          * @see Iterator::rewind()
1671          * @return void
1672          */
1673         public function rewind() {
1674                 $this->pos = 0;
1675                 $this->curShard = 0;
1676                 $this->setIteratorFromCurrentShard();
1677                 do {
1678                         $continue = false; // keep scanning shards?
1679                         $this->filterViaNext(); // filter out duplicates
1680                         // Find the next non-empty shard if no elements are left
1681                         if ( !$this->valid() ) {
1682                                 $this->nextShardIteratorIfNotValid();
1683                                 $continue = $this->valid(); // re-filter unless we ran out of shards
1684                         }
1685                 } while ( $continue );
1686         }
1687
1688         /**
1689          * Filter out duplicate items by advancing to the next ones
1690          */
1691         protected function filterViaNext() {
1692                 while ( $this->valid() ) {
1693                         $rel = $this->iter->current(); // path relative to given directory
1694                         $path = $this->params['dir'] . "/{$rel}"; // full storage path
1695                         if ( $this->backend->isSingleShardPathInternal( $path ) ) {
1696                                 break; // path is only on one shard; no issue with duplicates
1697                         } elseif ( isset( $this->multiShardPaths[$rel] ) ) {
1698                                 // Don't keep listing paths that are on multiple shards
1699                                 ( $this->iter instanceof Iterator ) ? $this->iter->next() : next( $this->iter );
1700                         } else {
1701                                 $this->multiShardPaths[$rel] = 1;
1702                                 break;
1703                         }
1704                 }
1705         }
1706
1707         /**
1708          * If the list iterator for this container shard is out of items,
1709          * then move on to the next container that has items.
1710          * If there are none, then it advances to the last container.
1711          */
1712         protected function nextShardIteratorIfNotValid() {
1713                 while ( !$this->valid() && ++$this->curShard < count( $this->shardSuffixes ) ) {
1714                         $this->setIteratorFromCurrentShard();
1715                 }
1716         }
1717
1718         /**
1719          * Set the list iterator to that of the current container shard
1720          */
1721         protected function setIteratorFromCurrentShard() {
1722                 $this->iter = $this->listFromShard(
1723                         $this->container . $this->shardSuffixes[$this->curShard],
1724                         $this->directory, $this->params );
1725                 // Start loading results so that current() works
1726                 if ( $this->iter ) {
1727                         ( $this->iter instanceof Iterator ) ? $this->iter->rewind() : reset( $this->iter );
1728                 }
1729         }
1730
1731         /**
1732          * Get the list for a given container shard
1733          *
1734          * @param $container string Resolved container name
1735          * @param $dir string Resolved path relative to container
1736          * @param $params Array
1737          * @return Traversable|Array|null
1738          */
1739         abstract protected function listFromShard( $container, $dir, array $params );
1740 }
1741
1742 /**
1743  * Iterator for listing directories
1744  */
1745 class FileBackendStoreShardDirIterator extends FileBackendStoreShardListIterator {
1746         /**
1747          * @see FileBackendStoreShardListIterator::listFromShard()
1748          * @return Array|null|Traversable
1749          */
1750         protected function listFromShard( $container, $dir, array $params ) {
1751                 return $this->backend->getDirectoryListInternal( $container, $dir, $params );
1752         }
1753 }
1754
1755 /**
1756  * Iterator for listing regular files
1757  */
1758 class FileBackendStoreShardFileIterator extends FileBackendStoreShardListIterator {
1759         /**
1760          * @see FileBackendStoreShardListIterator::listFromShard()
1761          * @return Array|null|Traversable
1762          */
1763         protected function listFromShard( $container, $dir, array $params ) {
1764                 return $this->backend->getFileListInternal( $container, $dir, $params );
1765         }
1766 }