includes/filebackend/SwiftFileBackend.php

   1 <?php
   2 /**
   3  * OpenStack Swift based file backend.
   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 Russ Nelson
  23  * @author Aaron Schulz
  24  */
  25
  26 /**
  27  * @brief Class for an OpenStack Swift (or Ceph RGW) based file backend.
  28  *
  29  * Status messages should avoid mentioning the Swift account name.
  30  * Likewise, error suppression should be used to avoid path disclosure.
  31  *
  32  * @ingroup FileBackend
  33  * @since 1.19
  34  */
  35 class SwiftFileBackend extends FileBackendStore {
  36         /** @var MultiHttpClient */
  37         protected $http;
  38
  39         /** @var int TTL in seconds */
  40         protected $authTTL;
  41
  42         /** @var string Authentication base URL (without version) */
  43         protected $swiftAuthUrl;
  44
  45         /** @var string Swift user (account:user) to authenticate as */
  46         protected $swiftUser;
  47
  48         /** @var string Secret key for user */
  49         protected $swiftKey;
  50
  51         /** @var string Shared secret value for making temp URLs */
  52         protected $swiftTempUrlKey;
  53
  54         /** @var string S3 access key (RADOS Gateway) */
  55         protected $rgwS3AccessKey;
  56
  57         /** @var string S3 authentication key (RADOS Gateway) */
  58         protected $rgwS3SecretKey;
  59
  60         /** @var BagOStuff */
  61         protected $srvCache;
  62
  63         /** @var ProcessCacheLRU Container stat cache */
  64         protected $containerStatCache;
  65
  66         /** @var array */
  67         protected $authCreds;
  68
  69         /** @var int UNIX timestamp */
  70         protected $authSessionTimestamp = 0;
  71
  72         /** @var int UNIX timestamp */
  73         protected $authErrorTimestamp = null;
  74
  75         /** @var bool Whether the server is an Ceph RGW */
  76         protected $isRGW = false;
  77
  78         /**
  79          * @see FileBackendStore::__construct()
  80          * Additional $config params include:
  81          *   - swiftAuthUrl       : Swift authentication server URL
  82          *   - swiftUser          : Swift user used by MediaWiki (account:username)
  83          *   - swiftKey           : Swift authentication key for the above user
  84          *   - swiftAuthTTL       : Swift authentication TTL (seconds)
  85          *   - swiftTempUrlKey    : Swift "X-Account-Meta-Temp-URL-Key" value on the account.
  86          *                          Do not set this until it has been set in the backend.
  87          *   - shardViaHashLevels : Map of container names to sharding config with:
  88          *                             - base   : base of hash characters, 16 or 36
  89          *                             - levels : the number of hash levels (and digits)
  90          *                             - repeat : hash subdirectories are prefixed with all the
  91          *                                        parent hash directory names (e.g. "a/ab/abc")
  92          *   - cacheAuthInfo      : Whether to cache authentication tokens in APC, XCache, ect.
  93          *                          If those are not available, then the main cache will be used.
  94          *                          This is probably insecure in shared hosting environments.
  95          *   - rgwS3AccessKey     : Rados Gateway S3 "access key" value on the account.
  96          *                          Do not set this until it has been set in the backend.
  97          *                          This is used for generating expiring pre-authenticated URLs.
  98          *                          Only use this when using rgw and to work around
  99          *                          http://tracker.newdream.net/issues/3454.
 100          *   - rgwS3SecretKey     : Rados Gateway S3 "secret key" value on the account.
 101          *                          Do not set this until it has been set in the backend.
 102          *                          This is used for generating expiring pre-authenticated URLs.
 103          *                          Only use this when using rgw and to work around
 104          *                          http://tracker.newdream.net/issues/3454.
 105          */
 106         public function __construct( array $config ) {
 107                 parent::__construct( $config );
 108                 // Required settings
 109                 $this->swiftAuthUrl = $config['swiftAuthUrl'];
 110                 $this->swiftUser = $config['swiftUser'];
 111                 $this->swiftKey = $config['swiftKey'];
 112                 // Optional settings
 113                 $this->authTTL = isset( $config['swiftAuthTTL'] )
 114                         ? $config['swiftAuthTTL']
 115                         : 15 * 60; // some sane number
 116                 $this->swiftTempUrlKey = isset( $config['swiftTempUrlKey'] )
 117                         ? $config['swiftTempUrlKey']
 118                         : '';
 119                 $this->shardViaHashLevels = isset( $config['shardViaHashLevels'] )
 120                         ? $config['shardViaHashLevels']
 121                         : '';
 122                 $this->rgwS3AccessKey = isset( $config['rgwS3AccessKey'] )
 123                         ? $config['rgwS3AccessKey']
 124                         : '';
 125                 $this->rgwS3SecretKey = isset( $config['rgwS3SecretKey'] )
 126                         ? $config['rgwS3SecretKey']
 127                         : '';
 128                 // HTTP helper client
 129                 $this->http = new MultiHttpClient( array() );
 130                 // Cache container information to mask latency
 131                 if ( isset( $config['wanCache'] ) && $config['wanCache'] instanceof WANObjectCache ) {
 132                         $this->memCache = $config['wanCache'];
 133                 }
 134                 // Process cache for container info
 135                 $this->containerStatCache = new ProcessCacheLRU( 300 );
 136                 // Cache auth token information to avoid RTTs
 137                 if ( !empty( $config['cacheAuthInfo'] ) ) {
 138                         if ( PHP_SAPI === 'cli' ) {
 139                                 $this->srvCache = wfGetMainCache(); // preferrably memcached
 140                         } else {
 141                                 try { // look for APC, XCache, WinCache, ect...
 142                                         $this->srvCache = ObjectCache::newAccelerator( array() );
 143                                 } catch ( Exception $e ) {
 144                                 }
 145                         }
 146                 }
 147                 $this->srvCache = $this->srvCache ?: new EmptyBagOStuff();
 148         }
 149
 150         public function getFeatures() {
 151                 return ( FileBackend::ATTR_UNICODE_PATHS |
 152                         FileBackend::ATTR_HEADERS | FileBackend::ATTR_METADATA );
 153         }
 154
 155         protected function resolveContainerPath( $container, $relStoragePath ) {
 156                 if ( !mb_check_encoding( $relStoragePath, 'UTF-8' ) ) { // mb_string required by CF
 157                         return null; // not UTF-8, makes it hard to use CF and the swift HTTP API
 158                 } elseif ( strlen( urlencode( $relStoragePath ) ) > 1024 ) {
 159                         return null; // too long for Swift
 160                 }
 161
 162                 return $relStoragePath;
 163         }
 164
 165         public function isPathUsableInternal( $storagePath ) {
 166                 list( $container, $rel ) = $this->resolveStoragePathReal( $storagePath );
 167                 if ( $rel === null ) {
 168                         return false; // invalid
 169                 }
 170
 171                 return is_array( $this->getContainerStat( $container ) );
 172         }
 173
 174         /**
 175          * Sanitize and filter the custom headers from a $params array.
 176          * We only allow certain Content- and X-Content- headers.
 177          *
 178          * @param array $params
 179          * @return array Sanitized value of 'headers' field in $params
 180          */
 181         protected function sanitizeHdrs( array $params ) {
 182                 $headers = array();
 183
 184                 // Normalize casing, and strip out illegal headers
 185                 if ( isset( $params['headers'] ) ) {
 186                         foreach ( $params['headers'] as $name => $value ) {
 187                                 $name = strtolower( $name );
 188                                 if ( preg_match( '/^content-(type|length)$/', $name ) ) {
 189                                         continue; // blacklisted
 190                                 } elseif ( preg_match( '/^(x-)?content-/', $name ) ) {
 191                                         $headers[$name] = $value; // allowed
 192                                 } elseif ( preg_match( '/^content-(disposition)/', $name ) ) {
 193                                         $headers[$name] = $value; // allowed
 194                                 }
 195                         }
 196                 }
 197                 // By default, Swift has annoyingly low maximum header value limits
 198                 if ( isset( $headers['content-disposition'] ) ) {
 199                         $disposition = '';
 200                         foreach ( explode( ';', $headers['content-disposition'] ) as $part ) {
 201                                 $part = trim( $part );
 202                                 $new = ( $disposition === '' ) ? $part : "{$disposition};{$part}";
 203                                 if ( strlen( $new ) <= 255 ) {
 204                                         $disposition = $new;
 205                                 } else {
 206                                         break; // too long; sigh
 207                                 }
 208                         }
 209                         $headers['content-disposition'] = $disposition;
 210                 }
 211
 212                 return $headers;
 213         }
 214
 215         protected function doCreateInternal( array $params ) {
 216                 $status = Status::newGood();
 217
 218                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 219                 if ( $dstRel === null ) {
 220                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 221
 222                         return $status;
 223                 }
 224
 225                 $sha1Hash = wfBaseConvert( sha1( $params['content'] ), 16, 36, 31 );
 226                 $contentType = $this->getContentType( $params['dst'], $params['content'], null );
 227
 228                 $reqs = array( array(
 229                         'method' => 'PUT',
 230                         'url' => array( $dstCont, $dstRel ),
 231                         'headers' => array(
 232                                 'content-length' => strlen( $params['content'] ),
 233                                 'etag' => md5( $params['content'] ),
 234                                 'content-type' => $contentType,
 235                                 'x-object-meta-sha1base36' => $sha1Hash
 236                         ) + $this->sanitizeHdrs( $params ),
 237                         'body' => $params['content']
 238                 ) );
 239
 240                 $that = $this;
 241                 $method = __METHOD__;
 242                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 243                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 244                         if ( $rcode === 201 ) {
 245                                 // good
 246                         } elseif ( $rcode === 412 ) {
 247                                 $status->fatal( 'backend-fail-contenttype', $params['dst'] );
 248                         } else {
 249                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 250                         }
 251                 };
 252
 253                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 254                 if ( !empty( $params['async'] ) ) { // deferred
 255                         $status->value = $opHandle;
 256                 } else { // actually write the object in Swift
 257                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 258                 }
 259
 260                 return $status;
 261         }
 262
 263         protected function doStoreInternal( array $params ) {
 264                 $status = Status::newGood();
 265
 266                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 267                 if ( $dstRel === null ) {
 268                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 269
 270                         return $status;
 271                 }
 272
 273                 MediaWiki\suppressWarnings();
 274                 $sha1Hash = sha1_file( $params['src'] );
 275                 MediaWiki\restoreWarnings();
 276                 if ( $sha1Hash === false ) { // source doesn't exist?
 277                         $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
 278
 279                         return $status;
 280                 }
 281                 $sha1Hash = wfBaseConvert( $sha1Hash, 16, 36, 31 );
 282                 $contentType = $this->getContentType( $params['dst'], null, $params['src'] );
 283
 284                 $handle = fopen( $params['src'], 'rb' );
 285                 if ( $handle === false ) { // source doesn't exist?
 286                         $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
 287
 288                         return $status;
 289                 }
 290
 291                 $reqs = array( array(
 292                         'method' => 'PUT',
 293                         'url' => array( $dstCont, $dstRel ),
 294                         'headers' => array(
 295                                 'content-length' => filesize( $params['src'] ),
 296                                 'etag' => md5_file( $params['src'] ),
 297                                 'content-type' => $contentType,
 298                                 'x-object-meta-sha1base36' => $sha1Hash
 299                         ) + $this->sanitizeHdrs( $params ),
 300                         'body' => $handle // resource
 301                 ) );
 302
 303                 $that = $this;
 304                 $method = __METHOD__;
 305                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 306                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 307                         if ( $rcode === 201 ) {
 308                                 // good
 309                         } elseif ( $rcode === 412 ) {
 310                                 $status->fatal( 'backend-fail-contenttype', $params['dst'] );
 311                         } else {
 312                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 313                         }
 314                 };
 315
 316                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 317                 if ( !empty( $params['async'] ) ) { // deferred
 318                         $status->value = $opHandle;
 319                 } else { // actually write the object in Swift
 320                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 321                 }
 322
 323                 return $status;
 324         }
 325
 326         protected function doCopyInternal( array $params ) {
 327                 $status = Status::newGood();
 328
 329                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 330                 if ( $srcRel === null ) {
 331                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 332
 333                         return $status;
 334                 }
 335
 336                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 337                 if ( $dstRel === null ) {
 338                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 339
 340                         return $status;
 341                 }
 342
 343                 $reqs = array( array(
 344                         'method' => 'PUT',
 345                         'url' => array( $dstCont, $dstRel ),
 346                         'headers' => array(
 347                                 'x-copy-from' => '/' . rawurlencode( $srcCont ) .
 348                                         '/' . str_replace( "%2F", "/", rawurlencode( $srcRel ) )
 349                         ) + $this->sanitizeHdrs( $params ), // extra headers merged into object
 350                 ) );
 351
 352                 $that = $this;
 353                 $method = __METHOD__;
 354                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 355                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 356                         if ( $rcode === 201 ) {
 357                                 // good
 358                         } elseif ( $rcode === 404 ) {
 359                                 $status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
 360                         } else {
 361                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 362                         }
 363                 };
 364
 365                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 366                 if ( !empty( $params['async'] ) ) { // deferred
 367                         $status->value = $opHandle;
 368                 } else { // actually write the object in Swift
 369                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 370                 }
 371
 372                 return $status;
 373         }
 374
 375         protected function doMoveInternal( array $params ) {
 376                 $status = Status::newGood();
 377
 378                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 379                 if ( $srcRel === null ) {
 380                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 381
 382                         return $status;
 383                 }
 384
 385                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 386                 if ( $dstRel === null ) {
 387                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 388
 389                         return $status;
 390                 }
 391
 392                 $reqs = array(
 393                         array(
 394                                 'method' => 'PUT',
 395                                 'url' => array( $dstCont, $dstRel ),
 396                                 'headers' => array(
 397                                         'x-copy-from' => '/' . rawurlencode( $srcCont ) .
 398                                                 '/' . str_replace( "%2F", "/", rawurlencode( $srcRel ) )
 399                                 ) + $this->sanitizeHdrs( $params ) // extra headers merged into object
 400                         )
 401                 );
 402                 if ( "{$srcCont}/{$srcRel}" !== "{$dstCont}/{$dstRel}" ) {
 403                         $reqs[] = array(
 404                                 'method' => 'DELETE',
 405                                 'url' => array( $srcCont, $srcRel ),
 406                                 'headers' => array()
 407                         );
 408                 }
 409
 410                 $that = $this;
 411                 $method = __METHOD__;
 412                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 413                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 414                         if ( $request['method'] === 'PUT' && $rcode === 201 ) {
 415                                 // good
 416                         } elseif ( $request['method'] === 'DELETE' && $rcode === 204 ) {
 417                                 // good
 418                         } elseif ( $rcode === 404 ) {
 419                                 $status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
 420                         } else {
 421                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 422                         }
 423                 };
 424
 425                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 426                 if ( !empty( $params['async'] ) ) { // deferred
 427                         $status->value = $opHandle;
 428                 } else { // actually move the object in Swift
 429                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 430                 }
 431
 432                 return $status;
 433         }
 434
 435         protected function doDeleteInternal( array $params ) {
 436                 $status = Status::newGood();
 437
 438                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 439                 if ( $srcRel === null ) {
 440                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 441
 442                         return $status;
 443                 }
 444
 445                 $reqs = array( array(
 446                         'method' => 'DELETE',
 447                         'url' => array( $srcCont, $srcRel ),
 448                         'headers' => array()
 449                 ) );
 450
 451                 $that = $this;
 452                 $method = __METHOD__;
 453                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 454                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 455                         if ( $rcode === 204 ) {
 456                                 // good
 457                         } elseif ( $rcode === 404 ) {
 458                                 if ( empty( $params['ignoreMissingSource'] ) ) {
 459                                         $status->fatal( 'backend-fail-delete', $params['src'] );
 460                                 }
 461                         } else {
 462                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 463                         }
 464                 };
 465
 466                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 467                 if ( !empty( $params['async'] ) ) { // deferred
 468                         $status->value = $opHandle;
 469                 } else { // actually delete the object in Swift
 470                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 471                 }
 472
 473                 return $status;
 474         }
 475
 476         protected function doDescribeInternal( array $params ) {
 477                 $status = Status::newGood();
 478
 479                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 480                 if ( $srcRel === null ) {
 481                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 482
 483                         return $status;
 484                 }
 485
 486                 // Fetch the old object headers/metadata...this should be in stat cache by now
 487                 $stat = $this->getFileStat( array( 'src' => $params['src'], 'latest' => 1 ) );
 488                 if ( $stat && !isset( $stat['xattr'] ) ) { // older cache entry
 489                         $stat = $this->doGetFileStat( array( 'src' => $params['src'], 'latest' => 1 ) );
 490                 }
 491                 if ( !$stat ) {
 492                         $status->fatal( 'backend-fail-describe', $params['src'] );
 493
 494                         return $status;
 495                 }
 496
 497                 // POST clears prior headers, so we need to merge the changes in to the old ones
 498                 $metaHdrs = array();
 499                 foreach ( $stat['xattr']['metadata'] as $name => $value ) {
 500                         $metaHdrs["x-object-meta-$name"] = $value;
 501                 }
 502                 $customHdrs = $this->sanitizeHdrs( $params ) + $stat['xattr']['headers'];
 503
 504                 $reqs = array( array(
 505                         'method' => 'POST',
 506                         'url' => array( $srcCont, $srcRel ),
 507                         'headers' => $metaHdrs + $customHdrs
 508                 ) );
 509
 510                 $that = $this;
 511                 $method = __METHOD__;
 512                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 513                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 514                         if ( $rcode === 202 ) {
 515                                 // good
 516                         } elseif ( $rcode === 404 ) {
 517                                 $status->fatal( 'backend-fail-describe', $params['src'] );
 518                         } else {
 519                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 520                         }
 521                 };
 522
 523                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 524                 if ( !empty( $params['async'] ) ) { // deferred
 525                         $status->value = $opHandle;
 526                 } else { // actually change the object in Swift
 527                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 528                 }
 529
 530                 return $status;
 531         }
 532
 533         protected function doPrepareInternal( $fullCont, $dir, array $params ) {
 534                 $status = Status::newGood();
 535
 536                 // (a) Check if container already exists
 537                 $stat = $this->getContainerStat( $fullCont );
 538                 if ( is_array( $stat ) ) {
 539                         return $status; // already there
 540                 } elseif ( $stat === null ) {
 541                         $status->fatal( 'backend-fail-internal', $this->name );
 542                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 543
 544                         return $status;
 545                 }
 546
 547                 // (b) Create container as needed with proper ACLs
 548                 if ( $stat === false ) {
 549                         $params['op'] = 'prepare';
 550                         $status->merge( $this->createContainer( $fullCont, $params ) );
 551                 }
 552
 553                 return $status;
 554         }
 555
 556         protected function doSecureInternal( $fullCont, $dir, array $params ) {
 557                 $status = Status::newGood();
 558                 if ( empty( $params['noAccess'] ) ) {
 559                         return $status; // nothing to do
 560                 }
 561
 562                 $stat = $this->getContainerStat( $fullCont );
 563                 if ( is_array( $stat ) ) {
 564                         // Make container private to end-users...
 565                         $status->merge( $this->setContainerAccess(
 566                                 $fullCont,
 567                                 array( $this->swiftUser ), // read
 568                                 array( $this->swiftUser ) // write
 569                         ) );
 570                 } elseif ( $stat === false ) {
 571                         $status->fatal( 'backend-fail-usable', $params['dir'] );
 572                 } else {
 573                         $status->fatal( 'backend-fail-internal', $this->name );
 574                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 575                 }
 576
 577                 return $status;
 578         }
 579
 580         protected function doPublishInternal( $fullCont, $dir, array $params ) {
 581                 $status = Status::newGood();
 582
 583                 $stat = $this->getContainerStat( $fullCont );
 584                 if ( is_array( $stat ) ) {
 585                         // Make container public to end-users...
 586                         $status->merge( $this->setContainerAccess(
 587                                 $fullCont,
 588                                 array( $this->swiftUser, '.r:*' ), // read
 589                                 array( $this->swiftUser ) // write
 590                         ) );
 591                 } elseif ( $stat === false ) {
 592                         $status->fatal( 'backend-fail-usable', $params['dir'] );
 593                 } else {
 594                         $status->fatal( 'backend-fail-internal', $this->name );
 595                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 596                 }
 597
 598                 return $status;
 599         }
 600
 601         protected function doCleanInternal( $fullCont, $dir, array $params ) {
 602                 $status = Status::newGood();
 603
 604                 // Only containers themselves can be removed, all else is virtual
 605                 if ( $dir != '' ) {
 606                         return $status; // nothing to do
 607                 }
 608
 609                 // (a) Check the container
 610                 $stat = $this->getContainerStat( $fullCont, true );
 611                 if ( $stat === false ) {
 612                         return $status; // ok, nothing to do
 613                 } elseif ( !is_array( $stat ) ) {
 614                         $status->fatal( 'backend-fail-internal', $this->name );
 615                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 616
 617                         return $status;
 618                 }
 619
 620                 // (b) Delete the container if empty
 621                 if ( $stat['count'] == 0 ) {
 622                         $params['op'] = 'clean';
 623                         $status->merge( $this->deleteContainer( $fullCont, $params ) );
 624                 }
 625
 626                 return $status;
 627         }
 628
 629         protected function doGetFileStat( array $params ) {
 630                 $params = array( 'srcs' => array( $params['src'] ), 'concurrency' => 1 ) + $params;
 631                 unset( $params['src'] );
 632                 $stats = $this->doGetFileStatMulti( $params );
 633
 634                 return reset( $stats );
 635         }
 636
 637         /**
 638          * Convert dates like "Tue, 03 Jan 2012 22:01:04 GMT"/"2013-05-11T07:37:27.678360Z".
 639          * Dates might also come in like "2013-05-11T07:37:27.678360" from Swift listings,
 640          * missing the timezone suffix (though Ceph RGW does not appear to have this bug).
 641          *
 642          * @param string $ts
 643          * @param int $format Output format (TS_* constant)
 644          * @return string
 645          * @throws FileBackendError
 646          */
 647         protected function convertSwiftDate( $ts, $format = TS_MW ) {
 648                 try {
 649                         $timestamp = new MWTimestamp( $ts );
 650
 651                         return $timestamp->getTimestamp( $format );
 652                 } catch ( Exception $e ) {
 653                         throw new FileBackendError( $e->getMessage() );
 654                 }
 655         }
 656
 657         /**
 658          * Fill in any missing object metadata and save it to Swift
 659          *
 660          * @param array $objHdrs Object response headers
 661          * @param string $path Storage path to object
 662          * @return array New headers
 663          */
 664         protected function addMissingMetadata( array $objHdrs, $path ) {
 665                 if ( isset( $objHdrs['x-object-meta-sha1base36'] ) ) {
 666                         return $objHdrs; // nothing to do
 667                 }
 668
 669                 /** @noinspection PhpUnusedLocalVariableInspection */
 670                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 671                 wfDebugLog( 'SwiftBackend', __METHOD__ . ": $path was not stored with SHA-1 metadata." );
 672
 673                 $objHdrs['x-object-meta-sha1base36'] = false;
 674
 675                 $auth = $this->getAuthentication();
 676                 if ( !$auth ) {
 677                         return $objHdrs; // failed
 678                 }
 679
 680                 $status = Status::newGood();
 681                 /** @noinspection PhpUnusedLocalVariableInspection */
 682                 $scopeLockS = $this->getScopedFileLocks( array( $path ), LockManager::LOCK_UW, $status );
 683                 if ( $status->isOK() ) {
 684                         $tmpFile = $this->getLocalCopy( array( 'src' => $path, 'latest' => 1 ) );
 685                         if ( $tmpFile ) {
 686                                 $hash = $tmpFile->getSha1Base36();
 687                                 if ( $hash !== false ) {
 688                                         $objHdrs['x-object-meta-sha1base36'] = $hash;
 689                                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
 690                                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
 691                                                 'method' => 'POST',
 692                                                 'url' => $this->storageUrl( $auth, $srcCont, $srcRel ),
 693                                                 'headers' => $this->authTokenHeaders( $auth ) + $objHdrs
 694                                         ) );
 695                                         if ( $rcode >= 200 && $rcode <= 299 ) {
 696                                                 $this->deleteFileCache( $path );
 697
 698                                                 return $objHdrs; // success
 699                                         }
 700                                 }
 701                         }
 702                 }
 703
 704                 wfDebugLog( 'SwiftBackend', __METHOD__ . ": unable to set SHA-1 metadata for $path" );
 705
 706                 return $objHdrs; // failed
 707         }
 708
 709         protected function doGetFileContentsMulti( array $params ) {
 710                 $contents = array();
 711
 712                 $auth = $this->getAuthentication();
 713
 714                 $ep = array_diff_key( $params, array( 'srcs' => 1 ) ); // for error logging
 715                 // Blindly create tmp files and stream to them, catching any exception if the file does
 716                 // not exist. Doing stats here is useless and will loop infinitely in addMissingMetadata().
 717                 $reqs = array(); // (path => op)
 718
 719                 foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
 720                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
 721                         if ( $srcRel === null || !$auth ) {
 722                                 $contents[$path] = false;
 723                                 continue;
 724                         }
 725                         // Create a new temporary memory file...
 726                         $handle = fopen( 'php://temp', 'wb' );
 727                         if ( $handle ) {
 728                                 $reqs[$path] = array(
 729                                         'method'  => 'GET',
 730                                         'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
 731                                         'headers' => $this->authTokenHeaders( $auth )
 732                                                 + $this->headersFromParams( $params ),
 733                                         'stream'  => $handle,
 734                                 );
 735                         }
 736                         $contents[$path] = false;
 737                 }
 738
 739                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
 740                 $reqs = $this->http->runMulti( $reqs, $opts );
 741                 foreach ( $reqs as $path => $op ) {
 742                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $op['response'];
 743                         if ( $rcode >= 200 && $rcode <= 299 ) {
 744                                 rewind( $op['stream'] ); // start from the beginning
 745                                 $contents[$path] = stream_get_contents( $op['stream'] );
 746                         } elseif ( $rcode === 404 ) {
 747                                 $contents[$path] = false;
 748                         } else {
 749                                 $this->onError( null, __METHOD__,
 750                                         array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
 751                         }
 752                         fclose( $op['stream'] ); // close open handle
 753                 }
 754
 755                 return $contents;
 756         }
 757
 758         protected function doDirectoryExists( $fullCont, $dir, array $params ) {
 759                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 760                 $status = $this->objectListing( $fullCont, 'names', 1, null, $prefix );
 761                 if ( $status->isOk() ) {
 762                         return ( count( $status->value ) ) > 0;
 763                 }
 764
 765                 return null; // error
 766         }
 767
 768         /**
 769          * @see FileBackendStore::getDirectoryListInternal()
 770          * @param string $fullCont
 771          * @param string $dir
 772          * @param array $params
 773          * @return SwiftFileBackendDirList
 774          */
 775         public function getDirectoryListInternal( $fullCont, $dir, array $params ) {
 776                 return new SwiftFileBackendDirList( $this, $fullCont, $dir, $params );
 777         }
 778
 779         /**
 780          * @see FileBackendStore::getFileListInternal()
 781          * @param string $fullCont
 782          * @param string $dir
 783          * @param array $params
 784          * @return SwiftFileBackendFileList
 785          */
 786         public function getFileListInternal( $fullCont, $dir, array $params ) {
 787                 return new SwiftFileBackendFileList( $this, $fullCont, $dir, $params );
 788         }
 789
 790         /**
 791          * Do not call this function outside of SwiftFileBackendFileList
 792          *
 793          * @param string $fullCont Resolved container name
 794          * @param string $dir Resolved storage directory with no trailing slash
 795          * @param string|null $after Resolved container relative path to list items after
 796          * @param int $limit Max number of items to list
 797          * @param array $params Parameters for getDirectoryList()
 798          * @return array List of container relative resolved paths of directories directly under $dir
 799          * @throws FileBackendError
 800          */
 801         public function getDirListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
 802                 $dirs = array();
 803                 if ( $after === INF ) {
 804                         return $dirs; // nothing more
 805                 }
 806
 807                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 808
 809                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 810                 // Non-recursive: only list dirs right under $dir
 811                 if ( !empty( $params['topOnly'] ) ) {
 812                         $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix, '/' );
 813                         if ( !$status->isOk() ) {
 814                                 return $dirs; // error
 815                         }
 816                         $objects = $status->value;
 817                         foreach ( $objects as $object ) { // files and directories
 818                                 if ( substr( $object, -1 ) === '/' ) {
 819                                         $dirs[] = $object; // directories end in '/'
 820                                 }
 821                         }
 822                 } else {
 823                         // Recursive: list all dirs under $dir and its subdirs
 824                         $getParentDir = function ( $path ) {
 825                                 return ( strpos( $path, '/' ) !== false ) ? dirname( $path ) : false;
 826                         };
 827
 828                         // Get directory from last item of prior page
 829                         $lastDir = $getParentDir( $after ); // must be first page
 830                         $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );
 831
 832                         if ( !$status->isOk() ) {
 833                                 return $dirs; // error
 834                         }
 835
 836                         $objects = $status->value;
 837
 838                         foreach ( $objects as $object ) { // files
 839                                 $objectDir = $getParentDir( $object ); // directory of object
 840
 841                                 if ( $objectDir !== false && $objectDir !== $dir ) {
 842                                         // Swift stores paths in UTF-8, using binary sorting.
 843                                         // See function "create_container_table" in common/db.py.
 844                                         // If a directory is not "greater" than the last one,
 845                                         // then it was already listed by the calling iterator.
 846                                         if ( strcmp( $objectDir, $lastDir ) > 0 ) {
 847                                                 $pDir = $objectDir;
 848                                                 do { // add dir and all its parent dirs
 849                                                         $dirs[] = "{$pDir}/";
 850                                                         $pDir = $getParentDir( $pDir );
 851                                                 } while ( $pDir !== false // sanity
 852                                                         && strcmp( $pDir, $lastDir ) > 0 // not done already
 853                                                         && strlen( $pDir ) > strlen( $dir ) // within $dir
 854                                                 );
 855                                         }
 856                                         $lastDir = $objectDir;
 857                                 }
 858                         }
 859                 }
 860                 // Page on the unfiltered directory listing (what is returned may be filtered)
 861                 if ( count( $objects ) < $limit ) {
 862                         $after = INF; // avoid a second RTT
 863                 } else {
 864                         $after = end( $objects ); // update last item
 865                 }
 866
 867                 return $dirs;
 868         }
 869
 870         /**
 871          * Do not call this function outside of SwiftFileBackendFileList
 872          *
 873          * @param string $fullCont Resolved container name
 874          * @param string $dir Resolved storage directory with no trailing slash
 875          * @param string|null $after Resolved container relative path of file to list items after
 876          * @param int $limit Max number of items to list
 877          * @param array $params Parameters for getDirectoryList()
 878          * @return array List of resolved container relative paths of files under $dir
 879          * @throws FileBackendError
 880          */
 881         public function getFileListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
 882                 $files = array(); // list of (path, stat array or null) entries
 883                 if ( $after === INF ) {
 884                         return $files; // nothing more
 885                 }
 886
 887                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 888
 889                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 890                 // $objects will contain a list of unfiltered names or CF_Object items
 891                 // Non-recursive: only list files right under $dir
 892                 if ( !empty( $params['topOnly'] ) ) {
 893                         if ( !empty( $params['adviseStat'] ) ) {
 894                                 $status = $this->objectListing( $fullCont, 'info', $limit, $after, $prefix, '/' );
 895                         } else {
 896                                 $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix, '/' );
 897                         }
 898                 } else {
 899                         // Recursive: list all files under $dir and its subdirs
 900                         if ( !empty( $params['adviseStat'] ) ) {
 901                                 $status = $this->objectListing( $fullCont, 'info', $limit, $after, $prefix );
 902                         } else {
 903                                 $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );
 904                         }
 905                 }
 906
 907                 // Reformat this list into a list of (name, stat array or null) entries
 908                 if ( !$status->isOk() ) {
 909                         return $files; // error
 910                 }
 911
 912                 $objects = $status->value;
 913                 $files = $this->buildFileObjectListing( $params, $dir, $objects );
 914
 915                 // Page on the unfiltered object listing (what is returned may be filtered)
 916                 if ( count( $objects ) < $limit ) {
 917                         $after = INF; // avoid a second RTT
 918                 } else {
 919                         $after = end( $objects ); // update last item
 920                         $after = is_object( $after ) ? $after->name : $after;
 921                 }
 922
 923                 return $files;
 924         }
 925
 926         /**
 927          * Build a list of file objects, filtering out any directories
 928          * and extracting any stat info if provided in $objects (for CF_Objects)
 929          *
 930          * @param array $params Parameters for getDirectoryList()
 931          * @param string $dir Resolved container directory path
 932          * @param array $objects List of CF_Object items or object names
 933          * @return array List of (names,stat array or null) entries
 934          */
 935         private function buildFileObjectListing( array $params, $dir, array $objects ) {
 936                 $names = array();
 937                 foreach ( $objects as $object ) {
 938                         if ( is_object( $object ) ) {
 939                                 if ( isset( $object->subdir ) || !isset( $object->name ) ) {
 940                                         continue; // virtual directory entry; ignore
 941                                 }
 942                                 $stat = array(
 943                                         // Convert various random Swift dates to TS_MW
 944                                         'mtime'  => $this->convertSwiftDate( $object->last_modified, TS_MW ),
 945                                         'size'   => (int)$object->bytes,
 946                                         'sha1'   => null,
 947                                         // Note: manifiest ETags are not an MD5 of the file
 948                                         'md5'    => ctype_xdigit( $object->hash ) ? $object->hash : null,
 949                                         'latest' => false // eventually consistent
 950                                 );
 951                                 $names[] = array( $object->name, $stat );
 952                         } elseif ( substr( $object, -1 ) !== '/' ) {
 953                                 // Omit directories, which end in '/' in listings
 954                                 $names[] = array( $object, null );
 955                         }
 956                 }
 957
 958                 return $names;
 959         }
 960
 961         /**
 962          * Do not call this function outside of SwiftFileBackendFileList
 963          *
 964          * @param string $path Storage path
 965          * @param array $val Stat value
 966          */
 967         public function loadListingStatInternal( $path, array $val ) {
 968                 $this->cheapCache->set( $path, 'stat', $val );
 969         }
 970
 971         protected function doGetFileXAttributes( array $params ) {
 972                 $stat = $this->getFileStat( $params );
 973                 if ( $stat ) {
 974                         if ( !isset( $stat['xattr'] ) ) {
 975                                 // Stat entries filled by file listings don't include metadata/headers
 976                                 $this->clearCache( array( $params['src'] ) );
 977                                 $stat = $this->getFileStat( $params );
 978                         }
 979
 980                         return $stat['xattr'];
 981                 } else {
 982                         return false;
 983                 }
 984         }
 985
 986         protected function doGetFileSha1base36( array $params ) {
 987                 $stat = $this->getFileStat( $params );
 988                 if ( $stat ) {
 989                         if ( !isset( $stat['sha1'] ) ) {
 990                                 // Stat entries filled by file listings don't include SHA1
 991                                 $this->clearCache( array( $params['src'] ) );
 992                                 $stat = $this->getFileStat( $params );
 993                         }
 994
 995                         return $stat['sha1'];
 996                 } else {
 997                         return false;
 998                 }
 999         }
1000
1001         protected function doStreamFile( array $params ) {
1002                 $status = Status::newGood();
1003
1004                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
1005                 if ( $srcRel === null ) {
1006                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
1007                 }
1008
1009                 $auth = $this->getAuthentication();
1010                 if ( !$auth || !is_array( $this->getContainerStat( $srcCont ) ) ) {
1011                         $status->fatal( 'backend-fail-stream', $params['src'] );
1012
1013                         return $status;
1014                 }
1015
1016                 $handle = fopen( 'php://output', 'wb' );
1017
1018                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1019                         'method' => 'GET',
1020                         'url' => $this->storageUrl( $auth, $srcCont, $srcRel ),
1021                         'headers' => $this->authTokenHeaders( $auth )
1022                                 + $this->headersFromParams( $params ),
1023                         'stream' => $handle,
1024                 ) );
1025
1026                 if ( $rcode >= 200 && $rcode <= 299 ) {
1027                         // good
1028                 } elseif ( $rcode === 404 ) {
1029                         $status->fatal( 'backend-fail-stream', $params['src'] );
1030                 } else {
1031                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1032                 }
1033
1034                 return $status;
1035         }
1036
1037         protected function doGetLocalCopyMulti( array $params ) {
1038                 $tmpFiles = array();
1039
1040                 $auth = $this->getAuthentication();
1041
1042                 $ep = array_diff_key( $params, array( 'srcs' => 1 ) ); // for error logging
1043                 // Blindly create tmp files and stream to them, catching any exception if the file does
1044                 // not exist. Doing a stat here is useless causes infinite loops in addMissingMetadata().
1045                 $reqs = array(); // (path => op)
1046
1047                 foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
1048                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
1049                         if ( $srcRel === null || !$auth ) {
1050                                 $tmpFiles[$path] = null;
1051                                 continue;
1052                         }
1053                         // Get source file extension
1054                         $ext = FileBackend::extensionFromPath( $path );
1055                         // Create a new temporary file...
1056                         $tmpFile = TempFSFile::factory( 'localcopy_', $ext );
1057                         if ( $tmpFile ) {
1058                                 $handle = fopen( $tmpFile->getPath(), 'wb' );
1059                                 if ( $handle ) {
1060                                         $reqs[$path] = array(
1061                                                 'method'  => 'GET',
1062                                                 'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
1063                                                 'headers' => $this->authTokenHeaders( $auth )
1064                                                         + $this->headersFromParams( $params ),
1065                                                 'stream'  => $handle,
1066                                         );
1067                                 } else {
1068                                         $tmpFile = null;
1069                                 }
1070                         }
1071                         $tmpFiles[$path] = $tmpFile;
1072                 }
1073
1074                 $isLatest = ( $this->isRGW || !empty( $params['latest'] ) );
1075                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
1076                 $reqs = $this->http->runMulti( $reqs, $opts );
1077                 foreach ( $reqs as $path => $op ) {
1078                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $op['response'];
1079                         fclose( $op['stream'] ); // close open handle
1080                         if ( $rcode >= 200 && $rcode <= 299 ) {
1081                                 $size = $tmpFiles[$path] ? $tmpFiles[$path]->getSize() : 0;
1082                                 // Double check that the disk is not full/broken
1083                                 if ( $size != $rhdrs['content-length'] ) {
1084                                         $tmpFiles[$path] = null;
1085                                         $rerr = "Got {$size}/{$rhdrs['content-length']} bytes";
1086                                         $this->onError( null, __METHOD__,
1087                                                 array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
1088                                 }
1089                                 // Set the file stat process cache in passing
1090                                 $stat = $this->getStatFromHeaders( $rhdrs );
1091                                 $stat['latest'] = $isLatest;
1092                                 $this->cheapCache->set( $path, 'stat', $stat );
1093                         } elseif ( $rcode === 404 ) {
1094                                 $tmpFiles[$path] = false;
1095                         } else {
1096                                 $tmpFiles[$path] = null;
1097                                 $this->onError( null, __METHOD__,
1098                                         array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
1099                         }
1100                 }
1101
1102                 return $tmpFiles;
1103         }
1104
1105         public function getFileHttpUrl( array $params ) {
1106                 if ( $this->swiftTempUrlKey != '' ||
1107                         ( $this->rgwS3AccessKey != '' && $this->rgwS3SecretKey != '' )
1108                 ) {
1109                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
1110                         if ( $srcRel === null ) {
1111                                 return null; // invalid path
1112                         }
1113
1114                         $auth = $this->getAuthentication();
1115                         if ( !$auth ) {
1116                                 return null;
1117                         }
1118
1119                         $ttl = isset( $params['ttl'] ) ? $params['ttl'] : 86400;
1120                         $expires = time() + $ttl;
1121
1122                         if ( $this->swiftTempUrlKey != '' ) {
1123                                 $url = $this->storageUrl( $auth, $srcCont, $srcRel );
1124                                 // Swift wants the signature based on the unencoded object name
1125                                 $contPath = parse_url( $this->storageUrl( $auth, $srcCont ), PHP_URL_PATH );
1126                                 $signature = hash_hmac( 'sha1',
1127                                         "GET\n{$expires}\n{$contPath}/{$srcRel}",
1128                                         $this->swiftTempUrlKey
1129                                 );
1130
1131                                 return "{$url}?temp_url_sig={$signature}&temp_url_expires={$expires}";
1132                         } else { // give S3 API URL for rgw
1133                                 // Path for signature starts with the bucket
1134                                 $spath = '/' . rawurlencode( $srcCont ) . '/' .
1135                                         str_replace( '%2F', '/', rawurlencode( $srcRel ) );
1136                                 // Calculate the hash
1137                                 $signature = base64_encode( hash_hmac(
1138                                         'sha1',
1139                                         "GET\n\n\n{$expires}\n{$spath}",
1140                                         $this->rgwS3SecretKey,
1141                                         true // raw
1142                                 ) );
1143                                 // See http://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html.
1144                                 // Note: adding a newline for empty CanonicalizedAmzHeaders does not work.
1145                                 return wfAppendQuery(
1146                                         str_replace( '/swift/v1', '', // S3 API is the rgw default
1147                                                 $this->storageUrl( $auth ) . $spath ),
1148                                         array(
1149                                                 'Signature' => $signature,
1150                                                 'Expires' => $expires,
1151                                                 'AWSAccessKeyId' => $this->rgwS3AccessKey )
1152                                 );
1153                         }
1154                 }
1155
1156                 return null;
1157         }
1158
1159         protected function directoriesAreVirtual() {
1160                 return true;
1161         }
1162
1163         /**
1164          * Get headers to send to Swift when reading a file based
1165          * on a FileBackend params array, e.g. that of getLocalCopy().
1166          * $params is currently only checked for a 'latest' flag.
1167          *
1168          * @param array $params
1169          * @return array
1170          */
1171         protected function headersFromParams( array $params ) {
1172                 $hdrs = array();
1173                 if ( !empty( $params['latest'] ) ) {
1174                         $hdrs['x-newest'] = 'true';
1175                 }
1176
1177                 return $hdrs;
1178         }
1179
1180         /**
1181          * @param FileBackendStoreOpHandle[] $fileOpHandles
1182          *
1183          * @return Status[]
1184          */
1185         protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
1186                 $statuses = array();
1187
1188                 $auth = $this->getAuthentication();
1189                 if ( !$auth ) {
1190                         foreach ( $fileOpHandles as $index => $fileOpHandle ) {
1191                                 $statuses[$index] = Status::newFatal( 'backend-fail-connect', $this->name );
1192                         }
1193
1194                         return $statuses;
1195                 }
1196
1197                 // Split the HTTP requests into stages that can be done concurrently
1198                 $httpReqsByStage = array(); // map of (stage => index => HTTP request)
1199                 foreach ( $fileOpHandles as $index => $fileOpHandle ) {
1200                         $reqs = $fileOpHandle->httpOp;
1201                         // Convert the 'url' parameter to an actual URL using $auth
1202                         foreach ( $reqs as $stage => &$req ) {
1203                                 list( $container, $relPath ) = $req['url'];
1204                                 $req['url'] = $this->storageUrl( $auth, $container, $relPath );
1205                                 $req['headers'] = isset( $req['headers'] ) ? $req['headers'] : array();
1206                                 $req['headers'] = $this->authTokenHeaders( $auth ) + $req['headers'];
1207                                 $httpReqsByStage[$stage][$index] = $req;
1208                         }
1209                         $statuses[$index] = Status::newGood();
1210                 }
1211
1212                 // Run all requests for the first stage, then the next, and so on
1213                 $reqCount = count( $httpReqsByStage );
1214                 for ( $stage = 0; $stage < $reqCount; ++$stage ) {
1215                         $httpReqs = $this->http->runMulti( $httpReqsByStage[$stage] );
1216                         foreach ( $httpReqs as $index => $httpReq ) {
1217                                 // Run the callback for each request of this operation
1218                                 $callback = $fileOpHandles[$index]->callback;
1219                                 call_user_func_array( $callback, array( $httpReq, $statuses[$index] ) );
1220                                 // On failure, abort all remaining requests for this operation
1221                                 // (e.g. abort the DELETE request if the COPY request fails for a move)
1222                                 if ( !$statuses[$index]->isOK() ) {
1223                                         $stages = count( $fileOpHandles[$index]->httpOp );
1224                                         for ( $s = ( $stage + 1 ); $s < $stages; ++$s ) {
1225                                                 unset( $httpReqsByStage[$s][$index] );
1226                                         }
1227                                 }
1228                         }
1229                 }
1230
1231                 return $statuses;
1232         }
1233
1234         /**
1235          * Set read/write permissions for a Swift container.
1236          *
1237          * @see http://swift.openstack.org/misc.html#acls
1238          *
1239          * In general, we don't allow listings to end-users. It's not useful, isn't well-defined
1240          * (lists are truncated to 10000 item with no way to page), and is just a performance risk.
1241          *
1242          * @param string $container Resolved Swift container
1243          * @param array $readGrps List of the possible criteria for a request to have
1244          * access to read a container. Each item is one of the following formats:
1245          *   - account:user        : Grants access if the request is by the given user
1246          *   - ".r:<regex>"        : Grants access if the request is from a referrer host that
1247          *                           matches the expression and the request is not for a listing.
1248          *                           Setting this to '*' effectively makes a container public.
1249          *   -".rlistings:<regex>" : Grants access if the request is from a referrer host that
1250          *                           matches the expression and the request is for a listing.
1251          * @param array $writeGrps A list of the possible criteria for a request to have
1252          * access to write to a container. Each item is of the following format:
1253          *   - account:user       : Grants access if the request is by the given user
1254          * @return Status
1255          */
1256         protected function setContainerAccess( $container, array $readGrps, array $writeGrps ) {
1257                 $status = Status::newGood();
1258                 $auth = $this->getAuthentication();
1259
1260                 if ( !$auth ) {
1261                         $status->fatal( 'backend-fail-connect', $this->name );
1262
1263                         return $status;
1264                 }
1265
1266                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1267                         'method' => 'POST',
1268                         'url' => $this->storageUrl( $auth, $container ),
1269                         'headers' => $this->authTokenHeaders( $auth ) + array(
1270                                 'x-container-read' => implode( ',', $readGrps ),
1271                                 'x-container-write' => implode( ',', $writeGrps )
1272                         )
1273                 ) );
1274
1275                 if ( $rcode != 204 && $rcode !== 202 ) {
1276                         $status->fatal( 'backend-fail-internal', $this->name );
1277                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': unexpected rcode value (' . $rcode . ')' );
1278                 }
1279
1280                 return $status;
1281         }
1282
1283         /**
1284          * Get a Swift container stat array, possibly from process cache.
1285          * Use $reCache if the file count or byte count is needed.
1286          *
1287          * @param string $container Container name
1288          * @param bool $bypassCache Bypass all caches and load from Swift
1289          * @return array|bool|null False on 404, null on failure
1290          */
1291         protected function getContainerStat( $container, $bypassCache = false ) {
1292                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
1293
1294                 if ( $bypassCache ) { // purge cache
1295                         $this->containerStatCache->clear( $container );
1296                 } elseif ( !$this->containerStatCache->has( $container, 'stat' ) ) {
1297                         $this->primeContainerCache( array( $container ) ); // check persistent cache
1298                 }
1299                 if ( !$this->containerStatCache->has( $container, 'stat' ) ) {
1300                         $auth = $this->getAuthentication();
1301                         if ( !$auth ) {
1302                                 return null;
1303                         }
1304
1305                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1306                                 'method' => 'HEAD',
1307                                 'url' => $this->storageUrl( $auth, $container ),
1308                                 'headers' => $this->authTokenHeaders( $auth )
1309                         ) );
1310
1311                         if ( $rcode === 204 ) {
1312                                 $stat = array(
1313                                         'count' => $rhdrs['x-container-object-count'],
1314                                         'bytes' => $rhdrs['x-container-bytes-used']
1315                                 );
1316                                 if ( $bypassCache ) {
1317                                         return $stat;
1318                                 } else {
1319                                         $this->containerStatCache->set( $container, 'stat', $stat ); // cache it
1320                                         $this->setContainerCache( $container, $stat ); // update persistent cache
1321                                 }
1322                         } elseif ( $rcode === 404 ) {
1323                                 return false;
1324                         } else {
1325                                 $this->onError( null, __METHOD__,
1326                                         array( 'cont' => $container ), $rerr, $rcode, $rdesc );
1327
1328                                 return null;
1329                         }
1330                 }
1331
1332                 return $this->containerStatCache->get( $container, 'stat' );
1333         }
1334
1335         /**
1336          * Create a Swift container
1337          *
1338          * @param string $container Container name
1339          * @param array $params
1340          * @return Status
1341          */
1342         protected function createContainer( $container, array $params ) {
1343                 $status = Status::newGood();
1344
1345                 $auth = $this->getAuthentication();
1346                 if ( !$auth ) {
1347                         $status->fatal( 'backend-fail-connect', $this->name );
1348
1349                         return $status;
1350                 }
1351
1352                 // @see SwiftFileBackend::setContainerAccess()
1353                 if ( empty( $params['noAccess'] ) ) {
1354                         $readGrps = array( '.r:*', $this->swiftUser ); // public
1355                 } else {
1356                         $readGrps = array( $this->swiftUser ); // private
1357                 }
1358                 $writeGrps = array( $this->swiftUser ); // sanity
1359
1360                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1361                         'method' => 'PUT',
1362                         'url' => $this->storageUrl( $auth, $container ),
1363                         'headers' => $this->authTokenHeaders( $auth ) + array(
1364                                 'x-container-read' => implode( ',', $readGrps ),
1365                                 'x-container-write' => implode( ',', $writeGrps )
1366                         )
1367                 ) );
1368
1369                 if ( $rcode === 201 ) { // new
1370                         // good
1371                 } elseif ( $rcode === 202 ) { // already there
1372                         // this shouldn't really happen, but is OK
1373                 } else {
1374                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1375                 }
1376
1377                 return $status;
1378         }
1379
1380         /**
1381          * Delete a Swift container
1382          *
1383          * @param string $container Container name
1384          * @param array $params
1385          * @return Status
1386          */
1387         protected function deleteContainer( $container, array $params ) {
1388                 $status = Status::newGood();
1389
1390                 $auth = $this->getAuthentication();
1391                 if ( !$auth ) {
1392                         $status->fatal( 'backend-fail-connect', $this->name );
1393
1394                         return $status;
1395                 }
1396
1397                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1398                         'method' => 'DELETE',
1399                         'url' => $this->storageUrl( $auth, $container ),
1400                         'headers' => $this->authTokenHeaders( $auth )
1401                 ) );
1402
1403                 if ( $rcode >= 200 && $rcode <= 299 ) { // deleted
1404                         $this->containerStatCache->clear( $container ); // purge
1405                 } elseif ( $rcode === 404 ) { // not there
1406                         // this shouldn't really happen, but is OK
1407                 } elseif ( $rcode === 409 ) { // not empty
1408                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc ); // race?
1409                 } else {
1410                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1411                 }
1412
1413                 return $status;
1414         }
1415
1416         /**
1417          * Get a list of objects under a container.
1418          * Either just the names or a list of stdClass objects with details can be returned.
1419          *
1420          * @param string $fullCont
1421          * @param string $type ('info' for a list of object detail maps, 'names' for names only)
1422          * @param int $limit
1423          * @param string|null $after
1424          * @param string|null $prefix
1425          * @param string|null $delim
1426          * @return Status With the list as value
1427          */
1428         private function objectListing(
1429                 $fullCont, $type, $limit, $after = null, $prefix = null, $delim = null
1430         ) {
1431                 $status = Status::newGood();
1432
1433                 $auth = $this->getAuthentication();
1434                 if ( !$auth ) {
1435                         $status->fatal( 'backend-fail-connect', $this->name );
1436
1437                         return $status;
1438                 }
1439
1440                 $query = array( 'limit' => $limit );
1441                 if ( $type === 'info' ) {
1442                         $query['format'] = 'json';
1443                 }
1444                 if ( $after !== null ) {
1445                         $query['marker'] = $after;
1446                 }
1447                 if ( $prefix !== null ) {
1448                         $query['prefix'] = $prefix;
1449                 }
1450                 if ( $delim !== null ) {
1451                         $query['delimiter'] = $delim;
1452                 }
1453
1454                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1455                         'method' => 'GET',
1456                         'url' => $this->storageUrl( $auth, $fullCont ),
1457                         'query' => $query,
1458                         'headers' => $this->authTokenHeaders( $auth )
1459                 ) );
1460
1461                 $params = array( 'cont' => $fullCont, 'prefix' => $prefix, 'delim' => $delim );
1462                 if ( $rcode === 200 ) { // good
1463                         if ( $type === 'info' ) {
1464                                 $status->value = FormatJson::decode( trim( $rbody ) );
1465                         } else {
1466                                 $status->value = explode( "\n", trim( $rbody ) );
1467                         }
1468                 } elseif ( $rcode === 204 ) {
1469                         $status->value = array(); // empty container
1470                 } elseif ( $rcode === 404 ) {
1471                         $status->value = array(); // no container
1472                 } else {
1473                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1474                 }
1475
1476                 return $status;
1477         }
1478
1479         protected function doPrimeContainerCache( array $containerInfo ) {
1480                 foreach ( $containerInfo as $container => $info ) {
1481                         $this->containerStatCache->set( $container, 'stat', $info );
1482                 }
1483         }
1484
1485         protected function doGetFileStatMulti( array $params ) {
1486                 $stats = array();
1487
1488                 $auth = $this->getAuthentication();
1489
1490                 $reqs = array();
1491                 foreach ( $params['srcs'] as $path ) {
1492                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
1493                         if ( $srcRel === null ) {
1494                                 $stats[$path] = false;
1495                                 continue; // invalid storage path
1496                         } elseif ( !$auth ) {
1497                                 $stats[$path] = null;
1498                                 continue;
1499                         }
1500
1501                         // (a) Check the container
1502                         $cstat = $this->getContainerStat( $srcCont );
1503                         if ( $cstat === false ) {
1504                                 $stats[$path] = false;
1505                                 continue; // ok, nothing to do
1506                         } elseif ( !is_array( $cstat ) ) {
1507                                 $stats[$path] = null;
1508                                 continue;
1509                         }
1510
1511                         $reqs[$path] = array(
1512                                 'method'  => 'HEAD',
1513                                 'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
1514                                 'headers' => $this->authTokenHeaders( $auth ) + $this->headersFromParams( $params )
1515                         );
1516                 }
1517
1518                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
1519                 $reqs = $this->http->runMulti( $reqs, $opts );
1520
1521                 foreach ( $params['srcs'] as $path ) {
1522                         if ( array_key_exists( $path, $stats ) ) {
1523                                 continue; // some sort of failure above
1524                         }
1525                         // (b) Check the file
1526                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $reqs[$path]['response'];
1527                         if ( $rcode === 200 || $rcode === 204 ) {
1528                                 // Update the object if it is missing some headers
1529                                 $rhdrs = $this->addMissingMetadata( $rhdrs, $path );
1530                                 // Load the stat array from the headers
1531                                 $stat = $this->getStatFromHeaders( $rhdrs );
1532                                 if ( $this->isRGW ) {
1533                                         $stat['latest'] = true; // strong consistency
1534                                 }
1535                         } elseif ( $rcode === 404 ) {
1536                                 $stat = false;
1537                         } else {
1538                                 $stat = null;
1539                                 $this->onError( null, __METHOD__, $params, $rerr, $rcode, $rdesc );
1540                         }
1541                         $stats[$path] = $stat;
1542                 }
1543
1544                 return $stats;
1545         }
1546
1547         /**
1548          * @param array $rhdrs
1549          * @return array
1550          */
1551         protected function getStatFromHeaders( array $rhdrs ) {
1552                 // Fetch all of the custom metadata headers
1553                 $metadata = array();
1554                 foreach ( $rhdrs as $name => $value ) {
1555                         if ( strpos( $name, 'x-object-meta-' ) === 0 ) {
1556                                 $metadata[substr( $name, strlen( 'x-object-meta-' ) )] = $value;
1557                         }
1558                 }
1559                 // Fetch all of the custom raw HTTP headers
1560                 $headers = $this->sanitizeHdrs( array( 'headers' => $rhdrs ) );
1561                 return array(
1562                         // Convert various random Swift dates to TS_MW
1563                         'mtime' => $this->convertSwiftDate( $rhdrs['last-modified'], TS_MW ),
1564                         // Empty objects actually return no content-length header in Ceph
1565                         'size'  => isset( $rhdrs['content-length'] ) ? (int)$rhdrs['content-length'] : 0,
1566                         'sha1'  => isset( $rhdrs['x-object-meta-sha1base36'] )
1567                                 ? $rhdrs['x-object-meta-sha1base36']
1568                                 : null,
1569                         // Note: manifiest ETags are not an MD5 of the file
1570                         'md5'   => ctype_xdigit( $rhdrs['etag'] ) ? $rhdrs['etag'] : null,
1571                         'xattr' => array( 'metadata' => $metadata, 'headers' => $headers )
1572                 );
1573         }
1574
1575         /**
1576          * @return array|null Credential map
1577          */
1578         protected function getAuthentication() {
1579                 if ( $this->authErrorTimestamp !== null ) {
1580                         if ( ( time() - $this->authErrorTimestamp ) < 60 ) {
1581                                 return null; // failed last attempt; don't bother
1582                         } else { // actually retry this time
1583                                 $this->authErrorTimestamp = null;
1584                         }
1585                 }
1586                 // Session keys expire after a while, so we renew them periodically
1587                 $reAuth = ( ( time() - $this->authSessionTimestamp ) > $this->authTTL );
1588                 // Authenticate with proxy and get a session key...
1589                 if ( !$this->authCreds || $reAuth ) {
1590                         $this->authSessionTimestamp = 0;
1591                         $cacheKey = $this->getCredsCacheKey( $this->swiftUser );
1592                         $creds = $this->srvCache->get( $cacheKey ); // credentials
1593                         // Try to use the credential cache
1594                         if ( isset( $creds['auth_token'] ) && isset( $creds['storage_url'] ) ) {
1595                                 $this->authCreds = $creds;
1596                                 // Skew the timestamp for worst case to avoid using stale credentials
1597                                 $this->authSessionTimestamp = time() - ceil( $this->authTTL / 2 );
1598                         } else { // cache miss
1599                                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1600                                         'method' => 'GET',
1601                                         'url' => "{$this->swiftAuthUrl}/v1.0",
1602                                         'headers' => array(
1603                                                 'x-auth-user' => $this->swiftUser,
1604                                                 'x-auth-key' => $this->swiftKey
1605                                         )
1606                                 ) );
1607
1608                                 if ( $rcode >= 200 && $rcode <= 299 ) { // OK
1609                                         $this->authCreds = array(
1610                                                 'auth_token' => $rhdrs['x-auth-token'],
1611                                                 'storage_url' => $rhdrs['x-storage-url']
1612                                         );
1613                                         $this->srvCache->set( $cacheKey, $this->authCreds, ceil( $this->authTTL / 2 ) );
1614                                         $this->authSessionTimestamp = time();
1615                                 } elseif ( $rcode === 401 ) {
1616                                         $this->onError( null, __METHOD__, array(), "Authentication failed.", $rcode );
1617                                         $this->authErrorTimestamp = time();
1618
1619                                         return null;
1620                                 } else {
1621                                         $this->onError( null, __METHOD__, array(), "HTTP return code: $rcode", $rcode );
1622                                         $this->authErrorTimestamp = time();
1623
1624                                         return null;
1625                                 }
1626                         }
1627                         // Ceph RGW does not use <account> in URLs (OpenStack Swift uses "/v1/<account>")
1628                         if ( substr( $this->authCreds['storage_url'], -3 ) === '/v1' ) {
1629                                 $this->isRGW = true; // take advantage of strong consistency in Ceph
1630                         }
1631                 }
1632
1633                 return $this->authCreds;
1634         }
1635
1636         /**
1637          * @param array $creds From getAuthentication()
1638          * @param string $container
1639          * @param string $object
1640          * @return array
1641          */
1642         protected function storageUrl( array $creds, $container = null, $object = null ) {
1643                 $parts = array( $creds['storage_url'] );
1644                 if ( strlen( $container ) ) {
1645                         $parts[] = rawurlencode( $container );
1646                 }
1647                 if ( strlen( $object ) ) {
1648                         $parts[] = str_replace( "%2F", "/", rawurlencode( $object ) );
1649                 }
1650
1651                 return implode( '/', $parts );
1652         }
1653
1654         /**
1655          * @param array $creds From getAuthentication()
1656          * @return array
1657          */
1658         protected function authTokenHeaders( array $creds ) {
1659                 return array( 'x-auth-token' => $creds['auth_token'] );
1660         }
1661
1662         /**
1663          * Get the cache key for a container
1664          *
1665          * @param string $username
1666          * @return string
1667          */
1668         private function getCredsCacheKey( $username ) {
1669                 return 'swiftcredentials:' . md5( $username . ':' . $this->swiftAuthUrl );
1670         }
1671
1672         /**
1673          * Log an unexpected exception for this backend.
1674          * This also sets the Status object to have a fatal error.
1675          *
1676          * @param Status|null $status
1677          * @param string $func
1678          * @param array $params
1679          * @param string $err Error string
1680          * @param int $code HTTP status
1681          * @param string $desc HTTP status description
1682          */
1683         public function onError( $status, $func, array $params, $err = '', $code = 0, $desc = '' ) {
1684                 if ( $status instanceof Status ) {
1685                         $status->fatal( 'backend-fail-internal', $this->name );
1686                 }
1687                 if ( $code == 401 ) { // possibly a stale token
1688                         $this->srvCache->delete( $this->getCredsCacheKey( $this->swiftUser ) );
1689                 }
1690                 wfDebugLog( 'SwiftBackend',
1691                         "HTTP $code ($desc) in '{$func}' (given '" . FormatJson::encode( $params ) . "')" .
1692                         ( $err ? ": $err" : "" )
1693                 );
1694         }
1695 }
1696
1697 /**
1698  * @see FileBackendStoreOpHandle
1699  */
1700 class SwiftFileOpHandle extends FileBackendStoreOpHandle {
1701         /** @var array List of Requests for MultiHttpClient */
1702         public $httpOp;
1703         /** @var Closure */
1704         public $callback;
1705
1706         /**
1707          * @param SwiftFileBackend $backend
1708          * @param Closure $callback Function that takes (HTTP request array, status)
1709          * @param array $httpOp MultiHttpClient op
1710          */
1711         public function __construct( SwiftFileBackend $backend, Closure $callback, array $httpOp ) {
1712                 $this->backend = $backend;
1713                 $this->callback = $callback;
1714                 $this->httpOp = $httpOp;
1715         }
1716 }
1717
1718 /**
1719  * SwiftFileBackend helper class to page through listings.
1720  * Swift also has a listing limit of 10,000 objects for sanity.
1721  * Do not use this class from places outside SwiftFileBackend.
1722  *
1723  * @ingroup FileBackend
1724  */
1725 abstract class SwiftFileBackendList implements Iterator {
1726         /** @var array List of path or (path,stat array) entries */
1727         protected $bufferIter = array();
1728
1729         /** @var string List items *after* this path */
1730         protected $bufferAfter = null;
1731
1732         /** @var int */
1733         protected $pos = 0;
1734
1735         /** @var array */
1736         protected $params = array();
1737
1738         /** @var SwiftFileBackend */
1739         protected $backend;
1740
1741         /** @var string Container name */
1742         protected $container;
1743
1744         /** @var string Storage directory */
1745         protected $dir;
1746
1747         /** @var int */
1748         protected $suffixStart;
1749
1750         const PAGE_SIZE = 9000; // file listing buffer size
1751
1752         /**
1753          * @param SwiftFileBackend $backend
1754          * @param string $fullCont Resolved container name
1755          * @param string $dir Resolved directory relative to container
1756          * @param array $params
1757          */
1758         public function __construct( SwiftFileBackend $backend, $fullCont, $dir, array $params ) {
1759                 $this->backend = $backend;
1760                 $this->container = $fullCont;
1761                 $this->dir = $dir;
1762                 if ( substr( $this->dir, -1 ) === '/' ) {
1763                         $this->dir = substr( $this->dir, 0, -1 ); // remove trailing slash
1764                 }
1765                 if ( $this->dir == '' ) { // whole container
1766                         $this->suffixStart = 0;
1767                 } else { // dir within container
1768                         $this->suffixStart = strlen( $this->dir ) + 1; // size of "path/to/dir/"
1769                 }
1770                 $this->params = $params;
1771         }
1772
1773         /**
1774          * @see Iterator::key()
1775          * @return int
1776          */
1777         public function key() {
1778                 return $this->pos;
1779         }
1780
1781         /**
1782          * @see Iterator::next()
1783          */
1784         public function next() {
1785                 // Advance to the next file in the page
1786                 next( $this->bufferIter );
1787                 ++$this->pos;
1788                 // Check if there are no files left in this page and
1789                 // advance to the next page if this page was not empty.
1790                 if ( !$this->valid() && count( $this->bufferIter ) ) {
1791                         $this->bufferIter = $this->pageFromList(
1792                                 $this->container, $this->dir, $this->bufferAfter, self::PAGE_SIZE, $this->params
1793                         ); // updates $this->bufferAfter
1794                 }
1795         }
1796
1797         /**
1798          * @see Iterator::rewind()
1799          */
1800         public function rewind() {
1801                 $this->pos = 0;
1802                 $this->bufferAfter = null;
1803                 $this->bufferIter = $this->pageFromList(
1804                         $this->container, $this->dir, $this->bufferAfter, self::PAGE_SIZE, $this->params
1805                 ); // updates $this->bufferAfter
1806         }
1807
1808         /**
1809          * @see Iterator::valid()
1810          * @return bool
1811          */
1812         public function valid() {
1813                 if ( $this->bufferIter === null ) {
1814                         return false; // some failure?
1815                 } else {
1816                         return ( current( $this->bufferIter ) !== false ); // no paths can have this value
1817                 }
1818         }
1819
1820         /**
1821          * Get the given list portion (page)
1822          *
1823          * @param string $container Resolved container name
1824          * @param string $dir Resolved path relative to container
1825          * @param string $after
1826          * @param int $limit
1827          * @param array $params
1828          * @return Traversable|array
1829          */
1830         abstract protected function pageFromList( $container, $dir, &$after, $limit, array $params );
1831 }
1832
1833 /**
1834  * Iterator for listing directories
1835  */
1836 class SwiftFileBackendDirList extends SwiftFileBackendList {
1837         /**
1838          * @see Iterator::current()
1839          * @return string|bool String (relative path) or false
1840          */
1841         public function current() {
1842                 return substr( current( $this->bufferIter ), $this->suffixStart, -1 );
1843         }
1844
1845         protected function pageFromList( $container, $dir, &$after, $limit, array $params ) {
1846                 return $this->backend->getDirListPageInternal( $container, $dir, $after, $limit, $params );
1847         }
1848 }
1849
1850 /**
1851  * Iterator for listing regular files
1852  */
1853 class SwiftFileBackendFileList extends SwiftFileBackendList {
1854         /**
1855          * @see Iterator::current()
1856          * @return string|bool String (relative path) or false
1857          */
1858         public function current() {
1859                 list( $path, $stat ) = current( $this->bufferIter );
1860                 $relPath = substr( $path, $this->suffixStart );
1861                 if ( is_array( $stat ) ) {
1862                         $storageDir = rtrim( $this->params['dir'], '/' );
1863                         $this->backend->loadListingStatInternal( "$storageDir/$relPath", $stat );
1864                 }
1865
1866                 return $relPath;
1867         }
1868
1869         protected function pageFromList( $container, $dir, &$after, $limit, array $params ) {
1870                 return $this->backend->getFileListPageInternal( $container, $dir, $after, $limit, $params );
1871         }
1872 }