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