includes/filebackend/SwiftFileBackend.php

   1 <?php
   2 /**
   3  * OpenStack Swift based file backend.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  * @author Russ Nelson
  23  * @author Aaron Schulz
  24  */
  25
  26 /**
  27  * @brief Class for an OpenStack Swift (or Ceph RGW) based file backend.
  28  *
  29  * Status messages should avoid mentioning the Swift account name.
  30  * Likewise, error suppression should be used to avoid path disclosure.
  31  *
  32  * @ingroup FileBackend
  33  * @since 1.19
  34  */
  35 class SwiftFileBackend extends FileBackendStore {
  36         /** @var MultiHttpClient */
  37         protected $http;
  38
  39         /** @var int TTL in seconds */
  40         protected $authTTL;
  41
  42         /** @var string Authentication base URL (without version) */
  43         protected $swiftAuthUrl;
  44
  45         /** @var string Swift user (account:user) to authenticate as */
  46         protected $swiftUser;
  47
  48         /** @var string Secret key for user */
  49         protected $swiftKey;
  50
  51         /** @var string Shared secret value for making temp URLs */
  52         protected $swiftTempUrlKey;
  53
  54         /** @var string S3 access key (RADOS Gateway) */
  55         protected $rgwS3AccessKey;
  56
  57         /** @var string S3 authentication key (RADOS Gateway) */
  58         protected $rgwS3SecretKey;
  59
  60         /** @var BagOStuff */
  61         protected $srvCache;
  62
  63         /** @var ProcessCacheLRU Container stat cache */
  64         protected $containerStatCache;
  65
  66         /** @var array */
  67         protected $authCreds;
  68
  69         /** @var int UNIX timestamp */
  70         protected $authSessionTimestamp = 0;
  71
  72         /** @var int UNIX timestamp */
  73         protected $authErrorTimestamp = null;
  74
  75         /** @var bool Whether the server is an Ceph RGW */
  76         protected $isRGW = false;
  77
  78         /**
  79          * @see FileBackendStore::__construct()
  80          * Additional $config params include:
  81          *   - swiftAuthUrl       : Swift authentication server URL
  82          *   - swiftUser          : Swift user used by MediaWiki (account:username)
  83          *   - swiftKey           : Swift authentication key for the above user
  84          *   - swiftAuthTTL       : Swift authentication TTL (seconds)
  85          *   - swiftTempUrlKey    : Swift "X-Account-Meta-Temp-URL-Key" value on the account.
  86          *                          Do not set this until it has been set in the backend.
  87          *   - shardViaHashLevels : Map of container names to sharding config with:
  88          *                             - base   : base of hash characters, 16 or 36
  89          *                             - levels : the number of hash levels (and digits)
  90          *                             - repeat : hash subdirectories are prefixed with all the
  91          *                                        parent hash directory names (e.g. "a/ab/abc")
  92          *   - cacheAuthInfo      : Whether to cache authentication tokens in APC, XCache, ect.
  93          *                          If those are not available, then the main cache will be used.
  94          *                          This is probably insecure in shared hosting environments.
  95          *   - rgwS3AccessKey     : Rados Gateway S3 "access key" value on the account.
  96          *                          Do not set this until it has been set in the backend.
  97          *                          This is used for generating expiring pre-authenticated URLs.
  98          *                          Only use this when using rgw and to work around
  99          *                          http://tracker.newdream.net/issues/3454.
 100          *   - rgwS3SecretKey     : Rados Gateway S3 "secret key" value on the account.
 101          *                          Do not set this until it has been set in the backend.
 102          *                          This is used for generating expiring pre-authenticated URLs.
 103          *                          Only use this when using rgw and to work around
 104          *                          http://tracker.newdream.net/issues/3454.
 105          */
 106         public function __construct( array $config ) {
 107                 parent::__construct( $config );
 108                 // Required settings
 109                 $this->swiftAuthUrl = $config['swiftAuthUrl'];
 110                 $this->swiftUser = $config['swiftUser'];
 111                 $this->swiftKey = $config['swiftKey'];
 112                 // Optional settings
 113                 $this->authTTL = isset( $config['swiftAuthTTL'] )
 114                         ? $config['swiftAuthTTL']
 115                         : 15 * 60; // some sane number
 116                 $this->swiftTempUrlKey = isset( $config['swiftTempUrlKey'] )
 117                         ? $config['swiftTempUrlKey']
 118                         : '';
 119                 $this->shardViaHashLevels = isset( $config['shardViaHashLevels'] )
 120                         ? $config['shardViaHashLevels']
 121                         : '';
 122                 $this->rgwS3AccessKey = isset( $config['rgwS3AccessKey'] )
 123                         ? $config['rgwS3AccessKey']
 124                         : '';
 125                 $this->rgwS3SecretKey = isset( $config['rgwS3SecretKey'] )
 126                         ? $config['rgwS3SecretKey']
 127                         : '';
 128                 // HTTP helper client
 129                 $this->http = new MultiHttpClient( array() );
 130                 // Cache container information to mask latency
 131                 if ( isset( $config['wanCache'] ) && $config['wanCache'] instanceof WANObjectCache ) {
 132                         $this->memCache = $config['wanCache'];
 133                 }
 134                 // Process cache for container info
 135                 $this->containerStatCache = new ProcessCacheLRU( 300 );
 136                 // Cache auth token information to avoid RTTs
 137                 if ( !empty( $config['cacheAuthInfo'] ) ) {
 138                         if ( PHP_SAPI === 'cli' ) {
 139                                 $this->srvCache = wfGetMainCache(); // preferrably memcached
 140                         } else {
 141                                 try { // look for APC, XCache, WinCache, ect...
 142                                         $this->srvCache = ObjectCache::newAccelerator( array() );
 143                                 } catch ( Exception $e ) {
 144                                 }
 145                         }
 146                 }
 147                 $this->srvCache = $this->srvCache ?: new EmptyBagOStuff();
 148         }
 149
 150         public function getFeatures() {
 151                 return ( FileBackend::ATTR_UNICODE_PATHS |
 152                         FileBackend::ATTR_HEADERS | FileBackend::ATTR_METADATA );
 153         }
 154
 155         protected function resolveContainerPath( $container, $relStoragePath ) {
 156                 if ( !mb_check_encoding( $relStoragePath, 'UTF-8' ) ) { // mb_string required by CF
 157                         return null; // not UTF-8, makes it hard to use CF and the swift HTTP API
 158                 } elseif ( strlen( urlencode( $relStoragePath ) ) > 1024 ) {
 159                         return null; // too long for Swift
 160                 }
 161
 162                 return $relStoragePath;
 163         }
 164
 165         public function isPathUsableInternal( $storagePath ) {
 166                 list( $container, $rel ) = $this->resolveStoragePathReal( $storagePath );
 167                 if ( $rel === null ) {
 168                         return false; // invalid
 169                 }
 170
 171                 return is_array( $this->getContainerStat( $container ) );
 172         }
 173
 174         /**
 175          * Sanitize and filter the custom headers from a $params array.
 176          * We only allow certain Content- and X-Content- headers.
 177          *
 178          * @param array $params
 179          * @return array Sanitized value of 'headers' field in $params
 180          */
 181         protected function sanitizeHdrs( array $params ) {
 182                 $headers = array();
 183
 184                 // Normalize casing, and strip out illegal headers
 185                 if ( isset( $params['headers'] ) ) {
 186                         foreach ( $params['headers'] as $name => $value ) {
 187                                 $name = strtolower( $name );
 188                                 if ( preg_match( '/^content-(type|length)$/', $name ) ) {
 189                                         continue; // blacklisted
 190                                 } elseif ( preg_match( '/^(x-)?content-/', $name ) ) {
 191                                         $headers[$name] = $value; // allowed
 192                                 } elseif ( preg_match( '/^content-(disposition)/', $name ) ) {
 193                                         $headers[$name] = $value; // allowed
 194                                 }
 195                         }
 196                 }
 197                 // By default, Swift has annoyingly low maximum header value limits
 198                 if ( isset( $headers['content-disposition'] ) ) {
 199                         $disposition = '';
 200                         // @note: assume FileBackend::makeContentDisposition() already used
 201                         foreach ( explode( ';', $headers['content-disposition'] ) as $part ) {
 202                                 $part = trim( $part );
 203                                 $new = ( $disposition === '' ) ? $part : "{$disposition};{$part}";
 204                                 if ( strlen( $new ) <= 255 ) {
 205                                         $disposition = $new;
 206                                 } else {
 207                                         break; // too long; sigh
 208                                 }
 209                         }
 210                         $headers['content-disposition'] = $disposition;
 211                 }
 212
 213                 return $headers;
 214         }
 215
 216         protected function doCreateInternal( array $params ) {
 217                 $status = Status::newGood();
 218
 219                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 220                 if ( $dstRel === null ) {
 221                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 222
 223                         return $status;
 224                 }
 225
 226                 $sha1Hash = wfBaseConvert( sha1( $params['content'] ), 16, 36, 31 );
 227                 $contentType = $this->getContentType( $params['dst'], $params['content'], null );
 228
 229                 $reqs = array( array(
 230                         'method' => 'PUT',
 231                         'url' => array( $dstCont, $dstRel ),
 232                         'headers' => array(
 233                                 'content-length' => strlen( $params['content'] ),
 234                                 'etag' => md5( $params['content'] ),
 235                                 'content-type' => $contentType,
 236                                 'x-object-meta-sha1base36' => $sha1Hash
 237                         ) + $this->sanitizeHdrs( $params ),
 238                         'body' => $params['content']
 239                 ) );
 240
 241                 $that = $this;
 242                 $method = __METHOD__;
 243                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 244                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 245                         if ( $rcode === 201 ) {
 246                                 // good
 247                         } elseif ( $rcode === 412 ) {
 248                                 $status->fatal( 'backend-fail-contenttype', $params['dst'] );
 249                         } else {
 250                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 251                         }
 252                 };
 253
 254                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 255                 if ( !empty( $params['async'] ) ) { // deferred
 256                         $status->value = $opHandle;
 257                 } else { // actually write the object in Swift
 258                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 259                 }
 260
 261                 return $status;
 262         }
 263
 264         protected function doStoreInternal( array $params ) {
 265                 $status = Status::newGood();
 266
 267                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 268                 if ( $dstRel === null ) {
 269                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 270
 271                         return $status;
 272                 }
 273
 274                 MediaWiki\suppressWarnings();
 275                 $sha1Hash = sha1_file( $params['src'] );
 276                 MediaWiki\restoreWarnings();
 277                 if ( $sha1Hash === false ) { // source doesn't exist?
 278                         $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
 279
 280                         return $status;
 281                 }
 282                 $sha1Hash = wfBaseConvert( $sha1Hash, 16, 36, 31 );
 283                 $contentType = $this->getContentType( $params['dst'], null, $params['src'] );
 284
 285                 $handle = fopen( $params['src'], 'rb' );
 286                 if ( $handle === false ) { // source doesn't exist?
 287                         $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
 288
 289                         return $status;
 290                 }
 291
 292                 $reqs = array( array(
 293                         'method' => 'PUT',
 294                         'url' => array( $dstCont, $dstRel ),
 295                         'headers' => array(
 296                                 'content-length' => filesize( $params['src'] ),
 297                                 'etag' => md5_file( $params['src'] ),
 298                                 'content-type' => $contentType,
 299                                 'x-object-meta-sha1base36' => $sha1Hash
 300                         ) + $this->sanitizeHdrs( $params ),
 301                         'body' => $handle // resource
 302                 ) );
 303
 304                 $that = $this;
 305                 $method = __METHOD__;
 306                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 307                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 308                         if ( $rcode === 201 ) {
 309                                 // good
 310                         } elseif ( $rcode === 412 ) {
 311                                 $status->fatal( 'backend-fail-contenttype', $params['dst'] );
 312                         } else {
 313                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 314                         }
 315                 };
 316
 317                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 318                 if ( !empty( $params['async'] ) ) { // deferred
 319                         $status->value = $opHandle;
 320                 } else { // actually write the object in Swift
 321                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 322                 }
 323
 324                 return $status;
 325         }
 326
 327         protected function doCopyInternal( array $params ) {
 328                 $status = Status::newGood();
 329
 330                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 331                 if ( $srcRel === null ) {
 332                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 333
 334                         return $status;
 335                 }
 336
 337                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 338                 if ( $dstRel === null ) {
 339                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 340
 341                         return $status;
 342                 }
 343
 344                 $reqs = array( array(
 345                         'method' => 'PUT',
 346                         'url' => array( $dstCont, $dstRel ),
 347                         'headers' => array(
 348                                 'x-copy-from' => '/' . rawurlencode( $srcCont ) .
 349                                         '/' . str_replace( "%2F", "/", rawurlencode( $srcRel ) )
 350                         ) + $this->sanitizeHdrs( $params ), // extra headers merged into object
 351                 ) );
 352
 353                 $that = $this;
 354                 $method = __METHOD__;
 355                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 356                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 357                         if ( $rcode === 201 ) {
 358                                 // good
 359                         } elseif ( $rcode === 404 ) {
 360                                 $status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
 361                         } else {
 362                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 363                         }
 364                 };
 365
 366                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 367                 if ( !empty( $params['async'] ) ) { // deferred
 368                         $status->value = $opHandle;
 369                 } else { // actually write the object in Swift
 370                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 371                 }
 372
 373                 return $status;
 374         }
 375
 376         protected function doMoveInternal( array $params ) {
 377                 $status = Status::newGood();
 378
 379                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 380                 if ( $srcRel === null ) {
 381                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 382
 383                         return $status;
 384                 }
 385
 386                 list( $dstCont, $dstRel ) = $this->resolveStoragePathReal( $params['dst'] );
 387                 if ( $dstRel === null ) {
 388                         $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 389
 390                         return $status;
 391                 }
 392
 393                 $reqs = array(
 394                         array(
 395                                 'method' => 'PUT',
 396                                 'url' => array( $dstCont, $dstRel ),
 397                                 'headers' => array(
 398                                         'x-copy-from' => '/' . rawurlencode( $srcCont ) .
 399                                                 '/' . str_replace( "%2F", "/", rawurlencode( $srcRel ) )
 400                                 ) + $this->sanitizeHdrs( $params ) // extra headers merged into object
 401                         )
 402                 );
 403                 if ( "{$srcCont}/{$srcRel}" !== "{$dstCont}/{$dstRel}" ) {
 404                         $reqs[] = array(
 405                                 'method' => 'DELETE',
 406                                 'url' => array( $srcCont, $srcRel ),
 407                                 'headers' => array()
 408                         );
 409                 }
 410
 411                 $that = $this;
 412                 $method = __METHOD__;
 413                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 414                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 415                         if ( $request['method'] === 'PUT' && $rcode === 201 ) {
 416                                 // good
 417                         } elseif ( $request['method'] === 'DELETE' && $rcode === 204 ) {
 418                                 // good
 419                         } elseif ( $rcode === 404 ) {
 420                                 $status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
 421                         } else {
 422                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 423                         }
 424                 };
 425
 426                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 427                 if ( !empty( $params['async'] ) ) { // deferred
 428                         $status->value = $opHandle;
 429                 } else { // actually move the object in Swift
 430                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 431                 }
 432
 433                 return $status;
 434         }
 435
 436         protected function doDeleteInternal( array $params ) {
 437                 $status = Status::newGood();
 438
 439                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 440                 if ( $srcRel === null ) {
 441                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 442
 443                         return $status;
 444                 }
 445
 446                 $reqs = array( array(
 447                         'method' => 'DELETE',
 448                         'url' => array( $srcCont, $srcRel ),
 449                         'headers' => array()
 450                 ) );
 451
 452                 $that = $this;
 453                 $method = __METHOD__;
 454                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 455                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 456                         if ( $rcode === 204 ) {
 457                                 // good
 458                         } elseif ( $rcode === 404 ) {
 459                                 if ( empty( $params['ignoreMissingSource'] ) ) {
 460                                         $status->fatal( 'backend-fail-delete', $params['src'] );
 461                                 }
 462                         } else {
 463                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 464                         }
 465                 };
 466
 467                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 468                 if ( !empty( $params['async'] ) ) { // deferred
 469                         $status->value = $opHandle;
 470                 } else { // actually delete the object in Swift
 471                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 472                 }
 473
 474                 return $status;
 475         }
 476
 477         protected function doDescribeInternal( array $params ) {
 478                 $status = Status::newGood();
 479
 480                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
 481                 if ( $srcRel === null ) {
 482                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 483
 484                         return $status;
 485                 }
 486
 487                 // Fetch the old object headers/metadata...this should be in stat cache by now
 488                 $stat = $this->getFileStat( array( 'src' => $params['src'], 'latest' => 1 ) );
 489                 if ( $stat && !isset( $stat['xattr'] ) ) { // older cache entry
 490                         $stat = $this->doGetFileStat( array( 'src' => $params['src'], 'latest' => 1 ) );
 491                 }
 492                 if ( !$stat ) {
 493                         $status->fatal( 'backend-fail-describe', $params['src'] );
 494
 495                         return $status;
 496                 }
 497
 498                 // POST clears prior headers, so we need to merge the changes in to the old ones
 499                 $metaHdrs = array();
 500                 foreach ( $stat['xattr']['metadata'] as $name => $value ) {
 501                         $metaHdrs["x-object-meta-$name"] = $value;
 502                 }
 503                 $customHdrs = $this->sanitizeHdrs( $params ) + $stat['xattr']['headers'];
 504
 505                 $reqs = array( array(
 506                         'method' => 'POST',
 507                         'url' => array( $srcCont, $srcRel ),
 508                         'headers' => $metaHdrs + $customHdrs
 509                 ) );
 510
 511                 $that = $this;
 512                 $method = __METHOD__;
 513                 $handler = function ( array $request, Status $status ) use ( $that, $method, $params ) {
 514                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $request['response'];
 515                         if ( $rcode === 202 ) {
 516                                 // good
 517                         } elseif ( $rcode === 404 ) {
 518                                 $status->fatal( 'backend-fail-describe', $params['src'] );
 519                         } else {
 520                                 $that->onError( $status, $method, $params, $rerr, $rcode, $rdesc );
 521                         }
 522                 };
 523
 524                 $opHandle = new SwiftFileOpHandle( $this, $handler, $reqs );
 525                 if ( !empty( $params['async'] ) ) { // deferred
 526                         $status->value = $opHandle;
 527                 } else { // actually change the object in Swift
 528                         $status->merge( current( $this->doExecuteOpHandlesInternal( array( $opHandle ) ) ) );
 529                 }
 530
 531                 return $status;
 532         }
 533
 534         protected function doPrepareInternal( $fullCont, $dir, array $params ) {
 535                 $status = Status::newGood();
 536
 537                 // (a) Check if container already exists
 538                 $stat = $this->getContainerStat( $fullCont );
 539                 if ( is_array( $stat ) ) {
 540                         return $status; // already there
 541                 } elseif ( $stat === null ) {
 542                         $status->fatal( 'backend-fail-internal', $this->name );
 543                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 544
 545                         return $status;
 546                 }
 547
 548                 // (b) Create container as needed with proper ACLs
 549                 if ( $stat === false ) {
 550                         $params['op'] = 'prepare';
 551                         $status->merge( $this->createContainer( $fullCont, $params ) );
 552                 }
 553
 554                 return $status;
 555         }
 556
 557         protected function doSecureInternal( $fullCont, $dir, array $params ) {
 558                 $status = Status::newGood();
 559                 if ( empty( $params['noAccess'] ) ) {
 560                         return $status; // nothing to do
 561                 }
 562
 563                 $stat = $this->getContainerStat( $fullCont );
 564                 if ( is_array( $stat ) ) {
 565                         // Make container private to end-users...
 566                         $status->merge( $this->setContainerAccess(
 567                                 $fullCont,
 568                                 array( $this->swiftUser ), // read
 569                                 array( $this->swiftUser ) // write
 570                         ) );
 571                 } elseif ( $stat === false ) {
 572                         $status->fatal( 'backend-fail-usable', $params['dir'] );
 573                 } else {
 574                         $status->fatal( 'backend-fail-internal', $this->name );
 575                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 576                 }
 577
 578                 return $status;
 579         }
 580
 581         protected function doPublishInternal( $fullCont, $dir, array $params ) {
 582                 $status = Status::newGood();
 583
 584                 $stat = $this->getContainerStat( $fullCont );
 585                 if ( is_array( $stat ) ) {
 586                         // Make container public to end-users...
 587                         $status->merge( $this->setContainerAccess(
 588                                 $fullCont,
 589                                 array( $this->swiftUser, '.r:*' ), // read
 590                                 array( $this->swiftUser ) // write
 591                         ) );
 592                 } elseif ( $stat === false ) {
 593                         $status->fatal( 'backend-fail-usable', $params['dir'] );
 594                 } else {
 595                         $status->fatal( 'backend-fail-internal', $this->name );
 596                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 597                 }
 598
 599                 return $status;
 600         }
 601
 602         protected function doCleanInternal( $fullCont, $dir, array $params ) {
 603                 $status = Status::newGood();
 604
 605                 // Only containers themselves can be removed, all else is virtual
 606                 if ( $dir != '' ) {
 607                         return $status; // nothing to do
 608                 }
 609
 610                 // (a) Check the container
 611                 $stat = $this->getContainerStat( $fullCont, true );
 612                 if ( $stat === false ) {
 613                         return $status; // ok, nothing to do
 614                 } elseif ( !is_array( $stat ) ) {
 615                         $status->fatal( 'backend-fail-internal', $this->name );
 616                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': cannot get container stat' );
 617
 618                         return $status;
 619                 }
 620
 621                 // (b) Delete the container if empty
 622                 if ( $stat['count'] == 0 ) {
 623                         $params['op'] = 'clean';
 624                         $status->merge( $this->deleteContainer( $fullCont, $params ) );
 625                 }
 626
 627                 return $status;
 628         }
 629
 630         protected function doGetFileStat( array $params ) {
 631                 $params = array( 'srcs' => array( $params['src'] ), 'concurrency' => 1 ) + $params;
 632                 unset( $params['src'] );
 633                 $stats = $this->doGetFileStatMulti( $params );
 634
 635                 return reset( $stats );
 636         }
 637
 638         /**
 639          * Convert dates like "Tue, 03 Jan 2012 22:01:04 GMT"/"2013-05-11T07:37:27.678360Z".
 640          * Dates might also come in like "2013-05-11T07:37:27.678360" from Swift listings,
 641          * missing the timezone suffix (though Ceph RGW does not appear to have this bug).
 642          *
 643          * @param string $ts
 644          * @param int $format Output format (TS_* constant)
 645          * @return string
 646          * @throws FileBackendError
 647          */
 648         protected function convertSwiftDate( $ts, $format = TS_MW ) {
 649                 try {
 650                         $timestamp = new MWTimestamp( $ts );
 651
 652                         return $timestamp->getTimestamp( $format );
 653                 } catch ( Exception $e ) {
 654                         throw new FileBackendError( $e->getMessage() );
 655                 }
 656         }
 657
 658         /**
 659          * Fill in any missing object metadata and save it to Swift
 660          *
 661          * @param array $objHdrs Object response headers
 662          * @param string $path Storage path to object
 663          * @return array New headers
 664          */
 665         protected function addMissingMetadata( array $objHdrs, $path ) {
 666                 if ( isset( $objHdrs['x-object-meta-sha1base36'] ) ) {
 667                         return $objHdrs; // nothing to do
 668                 }
 669
 670                 /** @noinspection PhpUnusedLocalVariableInspection */
 671                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 672                 wfDebugLog( 'SwiftBackend', __METHOD__ . ": $path was not stored with SHA-1 metadata." );
 673
 674                 $objHdrs['x-object-meta-sha1base36'] = false;
 675
 676                 $auth = $this->getAuthentication();
 677                 if ( !$auth ) {
 678                         return $objHdrs; // failed
 679                 }
 680
 681                 $status = Status::newGood();
 682                 /** @noinspection PhpUnusedLocalVariableInspection */
 683                 $scopeLockS = $this->getScopedFileLocks( array( $path ), LockManager::LOCK_UW, $status );
 684                 if ( $status->isOK() ) {
 685                         $tmpFile = $this->getLocalCopy( array( 'src' => $path, 'latest' => 1 ) );
 686                         if ( $tmpFile ) {
 687                                 $hash = $tmpFile->getSha1Base36();
 688                                 if ( $hash !== false ) {
 689                                         $objHdrs['x-object-meta-sha1base36'] = $hash;
 690                                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
 691                                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
 692                                                 'method' => 'POST',
 693                                                 'url' => $this->storageUrl( $auth, $srcCont, $srcRel ),
 694                                                 'headers' => $this->authTokenHeaders( $auth ) + $objHdrs
 695                                         ) );
 696                                         if ( $rcode >= 200 && $rcode <= 299 ) {
 697                                                 $this->deleteFileCache( $path );
 698
 699                                                 return $objHdrs; // success
 700                                         }
 701                                 }
 702                         }
 703                 }
 704
 705                 wfDebugLog( 'SwiftBackend', __METHOD__ . ": unable to set SHA-1 metadata for $path" );
 706
 707                 return $objHdrs; // failed
 708         }
 709
 710         protected function doGetFileContentsMulti( array $params ) {
 711                 $contents = array();
 712
 713                 $auth = $this->getAuthentication();
 714
 715                 $ep = array_diff_key( $params, array( 'srcs' => 1 ) ); // for error logging
 716                 // Blindly create tmp files and stream to them, catching any exception if the file does
 717                 // not exist. Doing stats here is useless and will loop infinitely in addMissingMetadata().
 718                 $reqs = array(); // (path => op)
 719
 720                 foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
 721                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
 722                         if ( $srcRel === null || !$auth ) {
 723                                 $contents[$path] = false;
 724                                 continue;
 725                         }
 726                         // Create a new temporary memory file...
 727                         $handle = fopen( 'php://temp', 'wb' );
 728                         if ( $handle ) {
 729                                 $reqs[$path] = array(
 730                                         'method'  => 'GET',
 731                                         'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
 732                                         'headers' => $this->authTokenHeaders( $auth )
 733                                                 + $this->headersFromParams( $params ),
 734                                         'stream'  => $handle,
 735                                 );
 736                         }
 737                         $contents[$path] = false;
 738                 }
 739
 740                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
 741                 $reqs = $this->http->runMulti( $reqs, $opts );
 742                 foreach ( $reqs as $path => $op ) {
 743                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $op['response'];
 744                         if ( $rcode >= 200 && $rcode <= 299 ) {
 745                                 rewind( $op['stream'] ); // start from the beginning
 746                                 $contents[$path] = stream_get_contents( $op['stream'] );
 747                         } elseif ( $rcode === 404 ) {
 748                                 $contents[$path] = false;
 749                         } else {
 750                                 $this->onError( null, __METHOD__,
 751                                         array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
 752                         }
 753                         fclose( $op['stream'] ); // close open handle
 754                 }
 755
 756                 return $contents;
 757         }
 758
 759         protected function doDirectoryExists( $fullCont, $dir, array $params ) {
 760                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 761                 $status = $this->objectListing( $fullCont, 'names', 1, null, $prefix );
 762                 if ( $status->isOk() ) {
 763                         return ( count( $status->value ) ) > 0;
 764                 }
 765
 766                 return null; // error
 767         }
 768
 769         /**
 770          * @see FileBackendStore::getDirectoryListInternal()
 771          * @param string $fullCont
 772          * @param string $dir
 773          * @param array $params
 774          * @return SwiftFileBackendDirList
 775          */
 776         public function getDirectoryListInternal( $fullCont, $dir, array $params ) {
 777                 return new SwiftFileBackendDirList( $this, $fullCont, $dir, $params );
 778         }
 779
 780         /**
 781          * @see FileBackendStore::getFileListInternal()
 782          * @param string $fullCont
 783          * @param string $dir
 784          * @param array $params
 785          * @return SwiftFileBackendFileList
 786          */
 787         public function getFileListInternal( $fullCont, $dir, array $params ) {
 788                 return new SwiftFileBackendFileList( $this, $fullCont, $dir, $params );
 789         }
 790
 791         /**
 792          * Do not call this function outside of SwiftFileBackendFileList
 793          *
 794          * @param string $fullCont Resolved container name
 795          * @param string $dir Resolved storage directory with no trailing slash
 796          * @param string|null $after Resolved container relative path to list items after
 797          * @param int $limit Max number of items to list
 798          * @param array $params Parameters for getDirectoryList()
 799          * @return array List of container relative resolved paths of directories directly under $dir
 800          * @throws FileBackendError
 801          */
 802         public function getDirListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
 803                 $dirs = array();
 804                 if ( $after === INF ) {
 805                         return $dirs; // nothing more
 806                 }
 807
 808                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 809
 810                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 811                 // Non-recursive: only list dirs right under $dir
 812                 if ( !empty( $params['topOnly'] ) ) {
 813                         $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix, '/' );
 814                         if ( !$status->isOk() ) {
 815                                 return $dirs; // error
 816                         }
 817                         $objects = $status->value;
 818                         foreach ( $objects as $object ) { // files and directories
 819                                 if ( substr( $object, -1 ) === '/' ) {
 820                                         $dirs[] = $object; // directories end in '/'
 821                                 }
 822                         }
 823                 } else {
 824                         // Recursive: list all dirs under $dir and its subdirs
 825                         $getParentDir = function ( $path ) {
 826                                 return ( strpos( $path, '/' ) !== false ) ? dirname( $path ) : false;
 827                         };
 828
 829                         // Get directory from last item of prior page
 830                         $lastDir = $getParentDir( $after ); // must be first page
 831                         $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );
 832
 833                         if ( !$status->isOk() ) {
 834                                 return $dirs; // error
 835                         }
 836
 837                         $objects = $status->value;
 838
 839                         foreach ( $objects as $object ) { // files
 840                                 $objectDir = $getParentDir( $object ); // directory of object
 841
 842                                 if ( $objectDir !== false && $objectDir !== $dir ) {
 843                                         // Swift stores paths in UTF-8, using binary sorting.
 844                                         // See function "create_container_table" in common/db.py.
 845                                         // If a directory is not "greater" than the last one,
 846                                         // then it was already listed by the calling iterator.
 847                                         if ( strcmp( $objectDir, $lastDir ) > 0 ) {
 848                                                 $pDir = $objectDir;
 849                                                 do { // add dir and all its parent dirs
 850                                                         $dirs[] = "{$pDir}/";
 851                                                         $pDir = $getParentDir( $pDir );
 852                                                 } while ( $pDir !== false // sanity
 853                                                         && strcmp( $pDir, $lastDir ) > 0 // not done already
 854                                                         && strlen( $pDir ) > strlen( $dir ) // within $dir
 855                                                 );
 856                                         }
 857                                         $lastDir = $objectDir;
 858                                 }
 859                         }
 860                 }
 861                 // Page on the unfiltered directory listing (what is returned may be filtered)
 862                 if ( count( $objects ) < $limit ) {
 863                         $after = INF; // avoid a second RTT
 864                 } else {
 865                         $after = end( $objects ); // update last item
 866                 }
 867
 868                 return $dirs;
 869         }
 870
 871         /**
 872          * Do not call this function outside of SwiftFileBackendFileList
 873          *
 874          * @param string $fullCont Resolved container name
 875          * @param string $dir Resolved storage directory with no trailing slash
 876          * @param string|null $after Resolved container relative path of file to list items after
 877          * @param int $limit Max number of items to list
 878          * @param array $params Parameters for getDirectoryList()
 879          * @return array List of resolved container relative paths of files under $dir
 880          * @throws FileBackendError
 881          */
 882         public function getFileListPageInternal( $fullCont, $dir, &$after, $limit, array $params ) {
 883                 $files = array(); // list of (path, stat array or null) entries
 884                 if ( $after === INF ) {
 885                         return $files; // nothing more
 886                 }
 887
 888                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
 889
 890                 $prefix = ( $dir == '' ) ? null : "{$dir}/";
 891                 // $objects will contain a list of unfiltered names or CF_Object items
 892                 // Non-recursive: only list files right under $dir
 893                 if ( !empty( $params['topOnly'] ) ) {
 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                 } else {
 900                         // Recursive: list all files under $dir and its subdirs
 901                         if ( !empty( $params['adviseStat'] ) ) {
 902                                 $status = $this->objectListing( $fullCont, 'info', $limit, $after, $prefix );
 903                         } else {
 904                                 $status = $this->objectListing( $fullCont, 'names', $limit, $after, $prefix );
 905                         }
 906                 }
 907
 908                 // Reformat this list into a list of (name, stat array or null) entries
 909                 if ( !$status->isOk() ) {
 910                         return $files; // error
 911                 }
 912
 913                 $objects = $status->value;
 914                 $files = $this->buildFileObjectListing( $params, $dir, $objects );
 915
 916                 // Page on the unfiltered object listing (what is returned may be filtered)
 917                 if ( count( $objects ) < $limit ) {
 918                         $after = INF; // avoid a second RTT
 919                 } else {
 920                         $after = end( $objects ); // update last item
 921                         $after = is_object( $after ) ? $after->name : $after;
 922                 }
 923
 924                 return $files;
 925         }
 926
 927         /**
 928          * Build a list of file objects, filtering out any directories
 929          * and extracting any stat info if provided in $objects (for CF_Objects)
 930          *
 931          * @param array $params Parameters for getDirectoryList()
 932          * @param string $dir Resolved container directory path
 933          * @param array $objects List of CF_Object items or object names
 934          * @return array List of (names,stat array or null) entries
 935          */
 936         private function buildFileObjectListing( array $params, $dir, array $objects ) {
 937                 $names = array();
 938                 foreach ( $objects as $object ) {
 939                         if ( is_object( $object ) ) {
 940                                 if ( isset( $object->subdir ) || !isset( $object->name ) ) {
 941                                         continue; // virtual directory entry; ignore
 942                                 }
 943                                 $stat = array(
 944                                         // Convert various random Swift dates to TS_MW
 945                                         'mtime'  => $this->convertSwiftDate( $object->last_modified, TS_MW ),
 946                                         'size'   => (int)$object->bytes,
 947                                         'sha1'   => null,
 948                                         // Note: manifiest ETags are not an MD5 of the file
 949                                         'md5'    => ctype_xdigit( $object->hash ) ? $object->hash : null,
 950                                         'latest' => false // eventually consistent
 951                                 );
 952                                 $names[] = array( $object->name, $stat );
 953                         } elseif ( substr( $object, -1 ) !== '/' ) {
 954                                 // Omit directories, which end in '/' in listings
 955                                 $names[] = array( $object, null );
 956                         }
 957                 }
 958
 959                 return $names;
 960         }
 961
 962         /**
 963          * Do not call this function outside of SwiftFileBackendFileList
 964          *
 965          * @param string $path Storage path
 966          * @param array $val Stat value
 967          */
 968         public function loadListingStatInternal( $path, array $val ) {
 969                 $this->cheapCache->set( $path, 'stat', $val );
 970         }
 971
 972         protected function doGetFileXAttributes( array $params ) {
 973                 $stat = $this->getFileStat( $params );
 974                 if ( $stat ) {
 975                         if ( !isset( $stat['xattr'] ) ) {
 976                                 // Stat entries filled by file listings don't include metadata/headers
 977                                 $this->clearCache( array( $params['src'] ) );
 978                                 $stat = $this->getFileStat( $params );
 979                         }
 980
 981                         return $stat['xattr'];
 982                 } else {
 983                         return false;
 984                 }
 985         }
 986
 987         protected function doGetFileSha1base36( array $params ) {
 988                 $stat = $this->getFileStat( $params );
 989                 if ( $stat ) {
 990                         if ( !isset( $stat['sha1'] ) ) {
 991                                 // Stat entries filled by file listings don't include SHA1
 992                                 $this->clearCache( array( $params['src'] ) );
 993                                 $stat = $this->getFileStat( $params );
 994                         }
 995
 996                         return $stat['sha1'];
 997                 } else {
 998                         return false;
 999                 }
1000         }
1001
1002         protected function doStreamFile( array $params ) {
1003                 $status = Status::newGood();
1004
1005                 list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
1006                 if ( $srcRel === null ) {
1007                         $status->fatal( 'backend-fail-invalidpath', $params['src'] );
1008                 }
1009
1010                 $auth = $this->getAuthentication();
1011                 if ( !$auth || !is_array( $this->getContainerStat( $srcCont ) ) ) {
1012                         $status->fatal( 'backend-fail-stream', $params['src'] );
1013
1014                         return $status;
1015                 }
1016
1017                 $handle = fopen( 'php://output', 'wb' );
1018
1019                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1020                         'method' => 'GET',
1021                         'url' => $this->storageUrl( $auth, $srcCont, $srcRel ),
1022                         'headers' => $this->authTokenHeaders( $auth )
1023                                 + $this->headersFromParams( $params ),
1024                         'stream' => $handle,
1025                 ) );
1026
1027                 if ( $rcode >= 200 && $rcode <= 299 ) {
1028                         // good
1029                 } elseif ( $rcode === 404 ) {
1030                         $status->fatal( 'backend-fail-stream', $params['src'] );
1031                 } else {
1032                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1033                 }
1034
1035                 return $status;
1036         }
1037
1038         protected function doGetLocalCopyMulti( array $params ) {
1039                 $tmpFiles = array();
1040
1041                 $auth = $this->getAuthentication();
1042
1043                 $ep = array_diff_key( $params, array( 'srcs' => 1 ) ); // for error logging
1044                 // Blindly create tmp files and stream to them, catching any exception if the file does
1045                 // not exist. Doing a stat here is useless causes infinite loops in addMissingMetadata().
1046                 $reqs = array(); // (path => op)
1047
1048                 foreach ( $params['srcs'] as $path ) { // each path in this concurrent batch
1049                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
1050                         if ( $srcRel === null || !$auth ) {
1051                                 $tmpFiles[$path] = null;
1052                                 continue;
1053                         }
1054                         // Get source file extension
1055                         $ext = FileBackend::extensionFromPath( $path );
1056                         // Create a new temporary file...
1057                         $tmpFile = TempFSFile::factory( 'localcopy_', $ext );
1058                         if ( $tmpFile ) {
1059                                 $handle = fopen( $tmpFile->getPath(), 'wb' );
1060                                 if ( $handle ) {
1061                                         $reqs[$path] = array(
1062                                                 'method'  => 'GET',
1063                                                 'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
1064                                                 'headers' => $this->authTokenHeaders( $auth )
1065                                                         + $this->headersFromParams( $params ),
1066                                                 'stream'  => $handle,
1067                                         );
1068                                 } else {
1069                                         $tmpFile = null;
1070                                 }
1071                         }
1072                         $tmpFiles[$path] = $tmpFile;
1073                 }
1074
1075                 $isLatest = ( $this->isRGW || !empty( $params['latest'] ) );
1076                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
1077                 $reqs = $this->http->runMulti( $reqs, $opts );
1078                 foreach ( $reqs as $path => $op ) {
1079                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $op['response'];
1080                         fclose( $op['stream'] ); // close open handle
1081                         if ( $rcode >= 200 && $rcode <= 299 ) {
1082                                 $size = $tmpFiles[$path] ? $tmpFiles[$path]->getSize() : 0;
1083                                 // Double check that the disk is not full/broken
1084                                 if ( $size != $rhdrs['content-length'] ) {
1085                                         $tmpFiles[$path] = null;
1086                                         $rerr = "Got {$size}/{$rhdrs['content-length']} bytes";
1087                                         $this->onError( null, __METHOD__,
1088                                                 array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
1089                                 }
1090                                 // Set the file stat process cache in passing
1091                                 $stat = $this->getStatFromHeaders( $rhdrs );
1092                                 $stat['latest'] = $isLatest;
1093                                 $this->cheapCache->set( $path, 'stat', $stat );
1094                         } elseif ( $rcode === 404 ) {
1095                                 $tmpFiles[$path] = false;
1096                         } else {
1097                                 $tmpFiles[$path] = null;
1098                                 $this->onError( null, __METHOD__,
1099                                         array( 'src' => $path ) + $ep, $rerr, $rcode, $rdesc );
1100                         }
1101                 }
1102
1103                 return $tmpFiles;
1104         }
1105
1106         public function getFileHttpUrl( array $params ) {
1107                 if ( $this->swiftTempUrlKey != '' ||
1108                         ( $this->rgwS3AccessKey != '' && $this->rgwS3SecretKey != '' )
1109                 ) {
1110                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $params['src'] );
1111                         if ( $srcRel === null ) {
1112                                 return null; // invalid path
1113                         }
1114
1115                         $auth = $this->getAuthentication();
1116                         if ( !$auth ) {
1117                                 return null;
1118                         }
1119
1120                         $ttl = isset( $params['ttl'] ) ? $params['ttl'] : 86400;
1121                         $expires = time() + $ttl;
1122
1123                         if ( $this->swiftTempUrlKey != '' ) {
1124                                 $url = $this->storageUrl( $auth, $srcCont, $srcRel );
1125                                 // Swift wants the signature based on the unencoded object name
1126                                 $contPath = parse_url( $this->storageUrl( $auth, $srcCont ), PHP_URL_PATH );
1127                                 $signature = hash_hmac( 'sha1',
1128                                         "GET\n{$expires}\n{$contPath}/{$srcRel}",
1129                                         $this->swiftTempUrlKey
1130                                 );
1131
1132                                 return "{$url}?temp_url_sig={$signature}&temp_url_expires={$expires}";
1133                         } else { // give S3 API URL for rgw
1134                                 // Path for signature starts with the bucket
1135                                 $spath = '/' . rawurlencode( $srcCont ) . '/' .
1136                                         str_replace( '%2F', '/', rawurlencode( $srcRel ) );
1137                                 // Calculate the hash
1138                                 $signature = base64_encode( hash_hmac(
1139                                         'sha1',
1140                                         "GET\n\n\n{$expires}\n{$spath}",
1141                                         $this->rgwS3SecretKey,
1142                                         true // raw
1143                                 ) );
1144                                 // See http://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html.
1145                                 // Note: adding a newline for empty CanonicalizedAmzHeaders does not work.
1146                                 return wfAppendQuery(
1147                                         str_replace( '/swift/v1', '', // S3 API is the rgw default
1148                                                 $this->storageUrl( $auth ) . $spath ),
1149                                         array(
1150                                                 'Signature' => $signature,
1151                                                 'Expires' => $expires,
1152                                                 'AWSAccessKeyId' => $this->rgwS3AccessKey )
1153                                 );
1154                         }
1155                 }
1156
1157                 return null;
1158         }
1159
1160         protected function directoriesAreVirtual() {
1161                 return true;
1162         }
1163
1164         /**
1165          * Get headers to send to Swift when reading a file based
1166          * on a FileBackend params array, e.g. that of getLocalCopy().
1167          * $params is currently only checked for a 'latest' flag.
1168          *
1169          * @param array $params
1170          * @return array
1171          */
1172         protected function headersFromParams( array $params ) {
1173                 $hdrs = array();
1174                 if ( !empty( $params['latest'] ) ) {
1175                         $hdrs['x-newest'] = 'true';
1176                 }
1177
1178                 return $hdrs;
1179         }
1180
1181         /**
1182          * @param FileBackendStoreOpHandle[] $fileOpHandles
1183          *
1184          * @return Status[]
1185          */
1186         protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
1187                 $statuses = array();
1188
1189                 $auth = $this->getAuthentication();
1190                 if ( !$auth ) {
1191                         foreach ( $fileOpHandles as $index => $fileOpHandle ) {
1192                                 $statuses[$index] = Status::newFatal( 'backend-fail-connect', $this->name );
1193                         }
1194
1195                         return $statuses;
1196                 }
1197
1198                 // Split the HTTP requests into stages that can be done concurrently
1199                 $httpReqsByStage = array(); // map of (stage => index => HTTP request)
1200                 foreach ( $fileOpHandles as $index => $fileOpHandle ) {
1201                         $reqs = $fileOpHandle->httpOp;
1202                         // Convert the 'url' parameter to an actual URL using $auth
1203                         foreach ( $reqs as $stage => &$req ) {
1204                                 list( $container, $relPath ) = $req['url'];
1205                                 $req['url'] = $this->storageUrl( $auth, $container, $relPath );
1206                                 $req['headers'] = isset( $req['headers'] ) ? $req['headers'] : array();
1207                                 $req['headers'] = $this->authTokenHeaders( $auth ) + $req['headers'];
1208                                 $httpReqsByStage[$stage][$index] = $req;
1209                         }
1210                         $statuses[$index] = Status::newGood();
1211                 }
1212
1213                 // Run all requests for the first stage, then the next, and so on
1214                 $reqCount = count( $httpReqsByStage );
1215                 for ( $stage = 0; $stage < $reqCount; ++$stage ) {
1216                         $httpReqs = $this->http->runMulti( $httpReqsByStage[$stage] );
1217                         foreach ( $httpReqs as $index => $httpReq ) {
1218                                 // Run the callback for each request of this operation
1219                                 $callback = $fileOpHandles[$index]->callback;
1220                                 call_user_func_array( $callback, array( $httpReq, $statuses[$index] ) );
1221                                 // On failure, abort all remaining requests for this operation
1222                                 // (e.g. abort the DELETE request if the COPY request fails for a move)
1223                                 if ( !$statuses[$index]->isOK() ) {
1224                                         $stages = count( $fileOpHandles[$index]->httpOp );
1225                                         for ( $s = ( $stage + 1 ); $s < $stages; ++$s ) {
1226                                                 unset( $httpReqsByStage[$s][$index] );
1227                                         }
1228                                 }
1229                         }
1230                 }
1231
1232                 return $statuses;
1233         }
1234
1235         /**
1236          * Set read/write permissions for a Swift container.
1237          *
1238          * @see http://swift.openstack.org/misc.html#acls
1239          *
1240          * In general, we don't allow listings to end-users. It's not useful, isn't well-defined
1241          * (lists are truncated to 10000 item with no way to page), and is just a performance risk.
1242          *
1243          * @param string $container Resolved Swift container
1244          * @param array $readGrps List of the possible criteria for a request to have
1245          * access to read a container. Each item is one of the following formats:
1246          *   - account:user        : Grants access if the request is by the given user
1247          *   - ".r:<regex>"        : Grants access if the request is from a referrer host that
1248          *                           matches the expression and the request is not for a listing.
1249          *                           Setting this to '*' effectively makes a container public.
1250          *   -".rlistings:<regex>" : Grants access if the request is from a referrer host that
1251          *                           matches the expression and the request is for a listing.
1252          * @param array $writeGrps A list of the possible criteria for a request to have
1253          * access to write to a container. Each item is of the following format:
1254          *   - account:user       : Grants access if the request is by the given user
1255          * @return Status
1256          */
1257         protected function setContainerAccess( $container, array $readGrps, array $writeGrps ) {
1258                 $status = Status::newGood();
1259                 $auth = $this->getAuthentication();
1260
1261                 if ( !$auth ) {
1262                         $status->fatal( 'backend-fail-connect', $this->name );
1263
1264                         return $status;
1265                 }
1266
1267                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1268                         'method' => 'POST',
1269                         'url' => $this->storageUrl( $auth, $container ),
1270                         'headers' => $this->authTokenHeaders( $auth ) + array(
1271                                 'x-container-read' => implode( ',', $readGrps ),
1272                                 'x-container-write' => implode( ',', $writeGrps )
1273                         )
1274                 ) );
1275
1276                 if ( $rcode != 204 && $rcode !== 202 ) {
1277                         $status->fatal( 'backend-fail-internal', $this->name );
1278                         wfDebugLog( 'SwiftBackend', __METHOD__ . ': unexpected rcode value (' . $rcode . ')' );
1279                 }
1280
1281                 return $status;
1282         }
1283
1284         /**
1285          * Get a Swift container stat array, possibly from process cache.
1286          * Use $reCache if the file count or byte count is needed.
1287          *
1288          * @param string $container Container name
1289          * @param bool $bypassCache Bypass all caches and load from Swift
1290          * @return array|bool|null False on 404, null on failure
1291          */
1292         protected function getContainerStat( $container, $bypassCache = false ) {
1293                 $ps = Profiler::instance()->scopedProfileIn( __METHOD__ . "-{$this->name}" );
1294
1295                 if ( $bypassCache ) { // purge cache
1296                         $this->containerStatCache->clear( $container );
1297                 } elseif ( !$this->containerStatCache->has( $container, 'stat' ) ) {
1298                         $this->primeContainerCache( array( $container ) ); // check persistent cache
1299                 }
1300                 if ( !$this->containerStatCache->has( $container, 'stat' ) ) {
1301                         $auth = $this->getAuthentication();
1302                         if ( !$auth ) {
1303                                 return null;
1304                         }
1305
1306                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1307                                 'method' => 'HEAD',
1308                                 'url' => $this->storageUrl( $auth, $container ),
1309                                 'headers' => $this->authTokenHeaders( $auth )
1310                         ) );
1311
1312                         if ( $rcode === 204 ) {
1313                                 $stat = array(
1314                                         'count' => $rhdrs['x-container-object-count'],
1315                                         'bytes' => $rhdrs['x-container-bytes-used']
1316                                 );
1317                                 if ( $bypassCache ) {
1318                                         return $stat;
1319                                 } else {
1320                                         $this->containerStatCache->set( $container, 'stat', $stat ); // cache it
1321                                         $this->setContainerCache( $container, $stat ); // update persistent cache
1322                                 }
1323                         } elseif ( $rcode === 404 ) {
1324                                 return false;
1325                         } else {
1326                                 $this->onError( null, __METHOD__,
1327                                         array( 'cont' => $container ), $rerr, $rcode, $rdesc );
1328
1329                                 return null;
1330                         }
1331                 }
1332
1333                 return $this->containerStatCache->get( $container, 'stat' );
1334         }
1335
1336         /**
1337          * Create a Swift container
1338          *
1339          * @param string $container Container name
1340          * @param array $params
1341          * @return Status
1342          */
1343         protected function createContainer( $container, array $params ) {
1344                 $status = Status::newGood();
1345
1346                 $auth = $this->getAuthentication();
1347                 if ( !$auth ) {
1348                         $status->fatal( 'backend-fail-connect', $this->name );
1349
1350                         return $status;
1351                 }
1352
1353                 // @see SwiftFileBackend::setContainerAccess()
1354                 if ( empty( $params['noAccess'] ) ) {
1355                         $readGrps = array( '.r:*', $this->swiftUser ); // public
1356                 } else {
1357                         $readGrps = array( $this->swiftUser ); // private
1358                 }
1359                 $writeGrps = array( $this->swiftUser ); // sanity
1360
1361                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1362                         'method' => 'PUT',
1363                         'url' => $this->storageUrl( $auth, $container ),
1364                         'headers' => $this->authTokenHeaders( $auth ) + array(
1365                                 'x-container-read' => implode( ',', $readGrps ),
1366                                 'x-container-write' => implode( ',', $writeGrps )
1367                         )
1368                 ) );
1369
1370                 if ( $rcode === 201 ) { // new
1371                         // good
1372                 } elseif ( $rcode === 202 ) { // already there
1373                         // this shouldn't really happen, but is OK
1374                 } else {
1375                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1376                 }
1377
1378                 return $status;
1379         }
1380
1381         /**
1382          * Delete a Swift container
1383          *
1384          * @param string $container Container name
1385          * @param array $params
1386          * @return Status
1387          */
1388         protected function deleteContainer( $container, array $params ) {
1389                 $status = Status::newGood();
1390
1391                 $auth = $this->getAuthentication();
1392                 if ( !$auth ) {
1393                         $status->fatal( 'backend-fail-connect', $this->name );
1394
1395                         return $status;
1396                 }
1397
1398                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1399                         'method' => 'DELETE',
1400                         'url' => $this->storageUrl( $auth, $container ),
1401                         'headers' => $this->authTokenHeaders( $auth )
1402                 ) );
1403
1404                 if ( $rcode >= 200 && $rcode <= 299 ) { // deleted
1405                         $this->containerStatCache->clear( $container ); // purge
1406                 } elseif ( $rcode === 404 ) { // not there
1407                         // this shouldn't really happen, but is OK
1408                 } elseif ( $rcode === 409 ) { // not empty
1409                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc ); // race?
1410                 } else {
1411                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1412                 }
1413
1414                 return $status;
1415         }
1416
1417         /**
1418          * Get a list of objects under a container.
1419          * Either just the names or a list of stdClass objects with details can be returned.
1420          *
1421          * @param string $fullCont
1422          * @param string $type ('info' for a list of object detail maps, 'names' for names only)
1423          * @param int $limit
1424          * @param string|null $after
1425          * @param string|null $prefix
1426          * @param string|null $delim
1427          * @return Status With the list as value
1428          */
1429         private function objectListing(
1430                 $fullCont, $type, $limit, $after = null, $prefix = null, $delim = null
1431         ) {
1432                 $status = Status::newGood();
1433
1434                 $auth = $this->getAuthentication();
1435                 if ( !$auth ) {
1436                         $status->fatal( 'backend-fail-connect', $this->name );
1437
1438                         return $status;
1439                 }
1440
1441                 $query = array( 'limit' => $limit );
1442                 if ( $type === 'info' ) {
1443                         $query['format'] = 'json';
1444                 }
1445                 if ( $after !== null ) {
1446                         $query['marker'] = $after;
1447                 }
1448                 if ( $prefix !== null ) {
1449                         $query['prefix'] = $prefix;
1450                 }
1451                 if ( $delim !== null ) {
1452                         $query['delimiter'] = $delim;
1453                 }
1454
1455                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1456                         'method' => 'GET',
1457                         'url' => $this->storageUrl( $auth, $fullCont ),
1458                         'query' => $query,
1459                         'headers' => $this->authTokenHeaders( $auth )
1460                 ) );
1461
1462                 $params = array( 'cont' => $fullCont, 'prefix' => $prefix, 'delim' => $delim );
1463                 if ( $rcode === 200 ) { // good
1464                         if ( $type === 'info' ) {
1465                                 $status->value = FormatJson::decode( trim( $rbody ) );
1466                         } else {
1467                                 $status->value = explode( "\n", trim( $rbody ) );
1468                         }
1469                 } elseif ( $rcode === 204 ) {
1470                         $status->value = array(); // empty container
1471                 } elseif ( $rcode === 404 ) {
1472                         $status->value = array(); // no container
1473                 } else {
1474                         $this->onError( $status, __METHOD__, $params, $rerr, $rcode, $rdesc );
1475                 }
1476
1477                 return $status;
1478         }
1479
1480         protected function doPrimeContainerCache( array $containerInfo ) {
1481                 foreach ( $containerInfo as $container => $info ) {
1482                         $this->containerStatCache->set( $container, 'stat', $info );
1483                 }
1484         }
1485
1486         protected function doGetFileStatMulti( array $params ) {
1487                 $stats = array();
1488
1489                 $auth = $this->getAuthentication();
1490
1491                 $reqs = array();
1492                 foreach ( $params['srcs'] as $path ) {
1493                         list( $srcCont, $srcRel ) = $this->resolveStoragePathReal( $path );
1494                         if ( $srcRel === null ) {
1495                                 $stats[$path] = false;
1496                                 continue; // invalid storage path
1497                         } elseif ( !$auth ) {
1498                                 $stats[$path] = null;
1499                                 continue;
1500                         }
1501
1502                         // (a) Check the container
1503                         $cstat = $this->getContainerStat( $srcCont );
1504                         if ( $cstat === false ) {
1505                                 $stats[$path] = false;
1506                                 continue; // ok, nothing to do
1507                         } elseif ( !is_array( $cstat ) ) {
1508                                 $stats[$path] = null;
1509                                 continue;
1510                         }
1511
1512                         $reqs[$path] = array(
1513                                 'method'  => 'HEAD',
1514                                 'url'     => $this->storageUrl( $auth, $srcCont, $srcRel ),
1515                                 'headers' => $this->authTokenHeaders( $auth ) + $this->headersFromParams( $params )
1516                         );
1517                 }
1518
1519                 $opts = array( 'maxConnsPerHost' => $params['concurrency'] );
1520                 $reqs = $this->http->runMulti( $reqs, $opts );
1521
1522                 foreach ( $params['srcs'] as $path ) {
1523                         if ( array_key_exists( $path, $stats ) ) {
1524                                 continue; // some sort of failure above
1525                         }
1526                         // (b) Check the file
1527                         list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $reqs[$path]['response'];
1528                         if ( $rcode === 200 || $rcode === 204 ) {
1529                                 // Update the object if it is missing some headers
1530                                 $rhdrs = $this->addMissingMetadata( $rhdrs, $path );
1531                                 // Load the stat array from the headers
1532                                 $stat = $this->getStatFromHeaders( $rhdrs );
1533                                 if ( $this->isRGW ) {
1534                                         $stat['latest'] = true; // strong consistency
1535                                 }
1536                         } elseif ( $rcode === 404 ) {
1537                                 $stat = false;
1538                         } else {
1539                                 $stat = null;
1540                                 $this->onError( null, __METHOD__, $params, $rerr, $rcode, $rdesc );
1541                         }
1542                         $stats[$path] = $stat;
1543                 }
1544
1545                 return $stats;
1546         }
1547
1548         /**
1549          * @param array $rhdrs
1550          * @return array
1551          */
1552         protected function getStatFromHeaders( array $rhdrs ) {
1553                 // Fetch all of the custom metadata headers
1554                 $metadata = array();
1555                 foreach ( $rhdrs as $name => $value ) {
1556                         if ( strpos( $name, 'x-object-meta-' ) === 0 ) {
1557                                 $metadata[substr( $name, strlen( 'x-object-meta-' ) )] = $value;
1558                         }
1559                 }
1560                 // Fetch all of the custom raw HTTP headers
1561                 $headers = $this->sanitizeHdrs( array( 'headers' => $rhdrs ) );
1562                 return array(
1563                         // Convert various random Swift dates to TS_MW
1564                         'mtime' => $this->convertSwiftDate( $rhdrs['last-modified'], TS_MW ),
1565                         // Empty objects actually return no content-length header in Ceph
1566                         'size'  => isset( $rhdrs['content-length'] ) ? (int)$rhdrs['content-length'] : 0,
1567                         'sha1'  => isset( $rhdrs['x-object-meta-sha1base36'] )
1568                                 ? $rhdrs['x-object-meta-sha1base36']
1569                                 : null,
1570                         // Note: manifiest ETags are not an MD5 of the file
1571                         'md5'   => ctype_xdigit( $rhdrs['etag'] ) ? $rhdrs['etag'] : null,
1572                         'xattr' => array( 'metadata' => $metadata, 'headers' => $headers )
1573                 );
1574         }
1575
1576         /**
1577          * @return array|null Credential map
1578          */
1579         protected function getAuthentication() {
1580                 if ( $this->authErrorTimestamp !== null ) {
1581                         if ( ( time() - $this->authErrorTimestamp ) < 60 ) {
1582                                 return null; // failed last attempt; don't bother
1583                         } else { // actually retry this time
1584                                 $this->authErrorTimestamp = null;
1585                         }
1586                 }
1587                 // Session keys expire after a while, so we renew them periodically
1588                 $reAuth = ( ( time() - $this->authSessionTimestamp ) > $this->authTTL );
1589                 // Authenticate with proxy and get a session key...
1590                 if ( !$this->authCreds || $reAuth ) {
1591                         $this->authSessionTimestamp = 0;
1592                         $cacheKey = $this->getCredsCacheKey( $this->swiftUser );
1593                         $creds = $this->srvCache->get( $cacheKey ); // credentials
1594                         // Try to use the credential cache
1595                         if ( isset( $creds['auth_token'] ) && isset( $creds['storage_url'] ) ) {
1596                                 $this->authCreds = $creds;
1597                                 // Skew the timestamp for worst case to avoid using stale credentials
1598                                 $this->authSessionTimestamp = time() - ceil( $this->authTTL / 2 );
1599                         } else { // cache miss
1600                                 list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( array(
1601                                         'method' => 'GET',
1602                                         'url' => "{$this->swiftAuthUrl}/v1.0",
1603                                         'headers' => array(
1604                                                 'x-auth-user' => $this->swiftUser,
1605                                                 'x-auth-key' => $this->swiftKey
1606                                         )
1607                                 ) );
1608
1609                                 if ( $rcode >= 200 && $rcode <= 299 ) { // OK
1610                                         $this->authCreds = array(
1611                                                 'auth_token' => $rhdrs['x-auth-token'],
1612                                                 'storage_url' => $rhdrs['x-storage-url']
1613                                         );
1614                                         $this->srvCache->set( $cacheKey, $this->authCreds, ceil( $this->authTTL / 2 ) );
1615                                         $this->authSessionTimestamp = time();
1616                                 } elseif ( $rcode === 401 ) {
1617                                         $this->onError( null, __METHOD__, array(), "Authentication failed.", $rcode );
1618                                         $this->authErrorTimestamp = time();
1619
1620                                         return null;
1621                                 } else {
1622                                         $this->onError( null, __METHOD__, array(), "HTTP return code: $rcode", $rcode );
1623                                         $this->authErrorTimestamp = time();
1624
1625                                         return null;
1626                                 }
1627                         }
1628                         // Ceph RGW does not use <account> in URLs (OpenStack Swift uses "/v1/<account>")
1629                         if ( substr( $this->authCreds['storage_url'], -3 ) === '/v1' ) {
1630                                 $this->isRGW = true; // take advantage of strong consistency in Ceph
1631                         }
1632                 }
1633
1634                 return $this->authCreds;
1635         }
1636
1637         /**
1638          * @param array $creds From getAuthentication()
1639          * @param string $container
1640          * @param string $object
1641          * @return array
1642          */
1643         protected function storageUrl( array $creds, $container = null, $object = null ) {
1644                 $parts = array( $creds['storage_url'] );
1645                 if ( strlen( $container ) ) {
1646                         $parts[] = rawurlencode( $container );
1647                 }
1648                 if ( strlen( $object ) ) {
1649                         $parts[] = str_replace( "%2F", "/", rawurlencode( $object ) );
1650                 }
1651
1652                 return implode( '/', $parts );
1653         }
1654
1655         /**
1656          * @param array $creds From getAuthentication()
1657          * @return array
1658          */
1659         protected function authTokenHeaders( array $creds ) {
1660                 return array( 'x-auth-token' => $creds['auth_token'] );
1661         }
1662
1663         /**
1664          * Get the cache key for a container
1665          *
1666          * @param string $username
1667          * @return string
1668          */
1669         private function getCredsCacheKey( $username ) {
1670                 return 'swiftcredentials:' . md5( $username . ':' . $this->swiftAuthUrl );
1671         }
1672
1673         /**
1674          * Log an unexpected exception for this backend.
1675          * This also sets the Status object to have a fatal error.
1676          *
1677          * @param Status|null $status
1678          * @param string $func
1679          * @param array $params
1680          * @param string $err Error string
1681          * @param int $code HTTP status
1682          * @param string $desc HTTP status description
1683          */
1684         public function onError( $status, $func, array $params, $err = '', $code = 0, $desc = '' ) {
1685                 if ( $status instanceof Status ) {
1686                         $status->fatal( 'backend-fail-internal', $this->name );
1687                 }
1688                 if ( $code == 401 ) { // possibly a stale token
1689                         $this->srvCache->delete( $this->getCredsCacheKey( $this->swiftUser ) );
1690                 }
1691                 wfDebugLog( 'SwiftBackend',
1692                         "HTTP $code ($desc) in '{$func}' (given '" . FormatJson::encode( $params ) . "')" .
1693                         ( $err ? ": $err" : "" )
1694                 );
1695         }
1696 }
1697
1698 /**
1699  * @see FileBackendStoreOpHandle
1700  */
1701 class SwiftFileOpHandle extends FileBackendStoreOpHandle {
1702         /** @var array List of Requests for MultiHttpClient */
1703         public $httpOp;
1704         /** @var Closure */
1705         public $callback;
1706
1707         /**
1708          * @param SwiftFileBackend $backend
1709          * @param Closure $callback Function that takes (HTTP request array, status)
1710          * @param array $httpOp MultiHttpClient op
1711          */
1712         public function __construct( SwiftFileBackend $backend, Closure $callback, array $httpOp ) {
1713                 $this->backend = $backend;
1714                 $this->callback = $callback;
1715                 $this->httpOp = $httpOp;
1716         }
1717 }
1718
1719 /**
1720  * SwiftFileBackend helper class to page through listings.
1721  * Swift also has a listing limit of 10,000 objects for sanity.
1722  * Do not use this class from places outside SwiftFileBackend.
1723  *
1724  * @ingroup FileBackend
1725  */
1726 abstract class SwiftFileBackendList implements Iterator {
1727         /** @var array List of path or (path,stat array) entries */
1728         protected $bufferIter = array();
1729
1730         /** @var string List items *after* this path */
1731         protected $bufferAfter = null;
1732
1733         /** @var int */
1734         protected $pos = 0;
1735
1736         /** @var array */
1737         protected $params = array();
1738
1739         /** @var SwiftFileBackend */
1740         protected $backend;
1741
1742         /** @var string Container name */
1743         protected $container;
1744
1745         /** @var string Storage directory */
1746         protected $dir;
1747
1748         /** @var int */
1749         protected $suffixStart;
1750
1751         const PAGE_SIZE = 9000; // file listing buffer size
1752
1753         /**
1754          * @param SwiftFileBackend $backend
1755          * @param string $fullCont Resolved container name
1756          * @param string $dir Resolved directory relative to container
1757          * @param array $params
1758          */
1759         public function __construct( SwiftFileBackend $backend, $fullCont, $dir, array $params ) {
1760                 $this->backend = $backend;
1761                 $this->container = $fullCont;
1762                 $this->dir = $dir;
1763                 if ( substr( $this->dir, -1 ) === '/' ) {
1764                         $this->dir = substr( $this->dir, 0, -1 ); // remove trailing slash
1765                 }
1766                 if ( $this->dir == '' ) { // whole container
1767                         $this->suffixStart = 0;
1768                 } else { // dir within container
1769                         $this->suffixStart = strlen( $this->dir ) + 1; // size of "path/to/dir/"
1770                 }
1771                 $this->params = $params;
1772         }
1773
1774         /**
1775          * @see Iterator::key()
1776          * @return int
1777          */
1778         public function key() {
1779                 return $this->pos;
1780         }
1781
1782         /**
1783          * @see Iterator::next()
1784          */
1785         public function next() {
1786                 // Advance to the next file in the page
1787                 next( $this->bufferIter );
1788                 ++$this->pos;
1789                 // Check if there are no files left in this page and
1790                 // advance to the next page if this page was not empty.
1791                 if ( !$this->valid() && count( $this->bufferIter ) ) {
1792                         $this->bufferIter = $this->pageFromList(
1793                                 $this->container, $this->dir, $this->bufferAfter, self::PAGE_SIZE, $this->params
1794                         ); // updates $this->bufferAfter
1795                 }
1796         }
1797
1798         /**
1799          * @see Iterator::rewind()
1800          */
1801         public function rewind() {
1802                 $this->pos = 0;
1803                 $this->bufferAfter = null;
1804                 $this->bufferIter = $this->pageFromList(
1805                         $this->container, $this->dir, $this->bufferAfter, self::PAGE_SIZE, $this->params
1806                 ); // updates $this->bufferAfter
1807         }
1808
1809         /**
1810          * @see Iterator::valid()
1811          * @return bool
1812          */
1813         public function valid() {
1814                 if ( $this->bufferIter === null ) {
1815                         return false; // some failure?
1816                 } else {
1817                         return ( current( $this->bufferIter ) !== false ); // no paths can have this value
1818                 }
1819         }
1820
1821         /**
1822          * Get the given list portion (page)
1823          *
1824          * @param string $container Resolved container name
1825          * @param string $dir Resolved path relative to container
1826          * @param string $after
1827          * @param int $limit
1828          * @param array $params
1829          * @return Traversable|array
1830          */
1831         abstract protected function pageFromList( $container, $dir, &$after, $limit, array $params );
1832 }
1833
1834 /**
1835  * Iterator for listing directories
1836  */
1837 class SwiftFileBackendDirList extends SwiftFileBackendList {
1838         /**
1839          * @see Iterator::current()
1840          * @return string|bool String (relative path) or false
1841          */
1842         public function current() {
1843                 return substr( current( $this->bufferIter ), $this->suffixStart, -1 );
1844         }
1845
1846         protected function pageFromList( $container, $dir, &$after, $limit, array $params ) {
1847                 return $this->backend->getDirListPageInternal( $container, $dir, $after, $limit, $params );
1848         }
1849 }
1850
1851 /**
1852  * Iterator for listing regular files
1853  */
1854 class SwiftFileBackendFileList extends SwiftFileBackendList {
1855         /**
1856          * @see Iterator::current()
1857          * @return string|bool String (relative path) or false
1858          */
1859         public function current() {
1860                 list( $path, $stat ) = current( $this->bufferIter );
1861                 $relPath = substr( $path, $this->suffixStart );
1862                 if ( is_array( $stat ) ) {
1863                         $storageDir = rtrim( $this->params['dir'], '/' );
1864                         $this->backend->loadListingStatInternal( "$storageDir/$relPath", $stat );
1865                 }
1866
1867                 return $relPath;
1868         }
1869
1870         protected function pageFromList( $container, $dir, &$after, $limit, array $params ) {
1871                 return $this->backend->getFileListPageInternal( $container, $dir, $after, $limit, $params );
1872         }
1873 }