includes/filerepo/file/File.php

   1 <?php
   2 /**
   3  * @defgroup FileAbstraction File abstraction
   4  * @ingroup FileRepo
   5  *
   6  * Represents files in a repository.
   7  */
   8
   9 /**
  10  * Base code for files.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  25  * http://www.gnu.org/copyleft/gpl.html
  26  *
  27  * @file
  28  * @ingroup FileAbstraction
  29  */
  30
  31 /**
  32  * Implements some public methods and some protected utility functions which
  33  * are required by multiple child classes. Contains stub functionality for
  34  * unimplemented public methods.
  35  *
  36  * Stub functions which should be overridden are marked with STUB. Some more
  37  * concrete functions are also typically overridden by child classes.
  38  *
  39  * Note that only the repo object knows what its file class is called. You should
  40  * never name a file class explictly outside of the repo class. Instead use the
  41  * repo's factory functions to generate file objects, for example:
  42  *
  43  * RepoGroup::singleton()->getLocalRepo()->newFile($title);
  44  *
  45  * The convenience functions wfLocalFile() and wfFindFile() should be sufficient
  46  * in most cases.
  47  *
  48  * @ingroup FileAbstraction
  49  */
  50 abstract class File {
  51         const DELETED_FILE = 1;
  52         const DELETED_COMMENT = 2;
  53         const DELETED_USER = 4;
  54         const DELETED_RESTRICTED = 8;
  55
  56         /** Force rendering in the current process */
  57         const RENDER_NOW   = 1;
  58         /**
  59          * Force rendering even if thumbnail already exist and using RENDER_NOW
  60          * I.e. you have to pass both flags: File::RENDER_NOW | File::RENDER_FORCE
  61          */
  62         const RENDER_FORCE = 2;
  63
  64         const DELETE_SOURCE = 1;
  65
  66         // Audience options for File::getDescription()
  67         const FOR_PUBLIC = 1;
  68         const FOR_THIS_USER = 2;
  69         const RAW = 3;
  70
  71         /**
  72          * Some member variables can be lazy-initialised using __get(). The
  73          * initialisation function for these variables is always a function named
  74          * like getVar(), where Var is the variable name with upper-case first
  75          * letter.
  76          *
  77          * The following variables are initialised in this way in this base class:
  78          *    name, extension, handler, path, canRender, isSafeFile,
  79          *    transformScript, hashPath, pageCount, url
  80          *
  81          * Code within this class should generally use the accessor function
  82          * directly, since __get() isn't re-entrant and therefore causes bugs that
  83          * depend on initialisation order.
  84          */
  85
  86         /**
  87          * The following member variables are not lazy-initialised
  88          */
  89
  90         /**
  91          * @var FileRepo|bool
  92          */
  93         var $repo;
  94
  95         /**
  96          * @var Title
  97          */
  98         var $title;
  99
 100         var $lastError, $redirected, $redirectedTitle;
 101
 102         /**
 103          * @var FSFile|bool False if undefined
 104          */
 105         protected $fsFile;
 106
 107         /**
 108          * @var MediaHandler
 109          */
 110         protected $handler;
 111
 112         /**
 113          * @var string
 114          */
 115         protected $url, $extension, $name, $path, $hashPath, $pageCount, $transformScript;
 116
 117         protected $redirectTitle;
 118
 119         /**
 120          * @var bool
 121          */
 122         protected $canRender, $isSafeFile;
 123
 124         /**
 125          * @var string Required Repository class type
 126          */
 127         protected $repoClass = 'FileRepo';
 128
 129         /**
 130          * Call this constructor from child classes.
 131          *
 132          * Both $title and $repo are optional, though some functions
 133          * may return false or throw exceptions if they are not set.
 134          * Most subclasses will want to call assertRepoDefined() here.
 135          *
 136          * @param $title Title|string|bool
 137          * @param $repo FileRepo|bool
 138          */
 139         function __construct( $title, $repo ) {
 140                 if ( $title !== false ) { // subclasses may not use MW titles
 141                         $title = self::normalizeTitle( $title, 'exception' );
 142                 }
 143                 $this->title = $title;
 144                 $this->repo = $repo;
 145         }
 146
 147         /**
 148          * Given a string or Title object return either a
 149          * valid Title object with namespace NS_FILE or null
 150          *
 151          * @param $title Title|string
 152          * @param $exception string|bool Use 'exception' to throw an error on bad titles
 153          * @throws MWException
 154          * @return Title|null
 155          */
 156         static function normalizeTitle( $title, $exception = false ) {
 157                 $ret = $title;
 158                 if ( $ret instanceof Title ) {
 159                         # Normalize NS_MEDIA -> NS_FILE
 160                         if ( $ret->getNamespace() == NS_MEDIA ) {
 161                                 $ret = Title::makeTitleSafe( NS_FILE, $ret->getDBkey() );
 162                         # Sanity check the title namespace
 163                         } elseif ( $ret->getNamespace() !== NS_FILE ) {
 164                                 $ret = null;
 165                         }
 166                 } else {
 167                         # Convert strings to Title objects
 168                         $ret = Title::makeTitleSafe( NS_FILE, (string)$ret );
 169                 }
 170                 if ( !$ret && $exception !== false ) {
 171                         throw new MWException( "`$title` is not a valid file title." );
 172                 }
 173                 return $ret;
 174         }
 175
 176         function __get( $name ) {
 177                 $function = array( $this, 'get' . ucfirst( $name ) );
 178                 if ( !is_callable( $function ) ) {
 179                         return null;
 180                 } else {
 181                         $this->$name = call_user_func( $function );
 182                         return $this->$name;
 183                 }
 184         }
 185
 186         /**
 187          * Normalize a file extension to the common form, and ensure it's clean.
 188          * Extensions with non-alphanumeric characters will be discarded.
 189          *
 190          * @param $ext string (without the .)
 191          * @return string
 192          */
 193         static function normalizeExtension( $ext ) {
 194                 $lower = strtolower( $ext );
 195                 $squish = array(
 196                         'htm' => 'html',
 197                         'jpeg' => 'jpg',
 198                         'mpeg' => 'mpg',
 199                         'tiff' => 'tif',
 200                         'ogv' => 'ogg' );
 201                 if( isset( $squish[$lower] ) ) {
 202                         return $squish[$lower];
 203                 } elseif( preg_match( '/^[0-9a-z]+$/', $lower ) ) {
 204                         return $lower;
 205                 } else {
 206                         return '';
 207                 }
 208         }
 209
 210         /**
 211          * Checks if file extensions are compatible
 212          *
 213          * @param $old File Old file
 214          * @param $new string New name
 215          *
 216          * @return bool|null
 217          */
 218         static function checkExtensionCompatibility( File $old, $new ) {
 219                 $oldMime = $old->getMimeType();
 220                 $n = strrpos( $new, '.' );
 221                 $newExt = self::normalizeExtension( $n ? substr( $new, $n + 1 ) : '' );
 222                 $mimeMagic = MimeMagic::singleton();
 223                 return $mimeMagic->isMatchingExtension( $newExt, $oldMime );
 224         }
 225
 226         /**
 227          * Upgrade the database row if there is one
 228          * Called by ImagePage
 229          * STUB
 230          */
 231         function upgradeRow() {}
 232
 233         /**
 234          * Split an internet media type into its two components; if not
 235          * a two-part name, set the minor type to 'unknown'.
 236          *
 237          * @param string $mime "text/html" etc
 238          * @return array ("text", "html") etc
 239          */
 240         public static function splitMime( $mime ) {
 241                 if( strpos( $mime, '/' ) !== false ) {
 242                         return explode( '/', $mime, 2 );
 243                 } else {
 244                         return array( $mime, 'unknown' );
 245                 }
 246         }
 247
 248         /**
 249          * Callback for usort() to do file sorts by name
 250          *
 251          * @param $a File
 252          * @param $b File
 253          *
 254          * @return Integer: result of name comparison
 255          */
 256         public static function compare( File $a, File $b ) {
 257                 return strcmp( $a->getName(), $b->getName() );
 258         }
 259
 260         /**
 261          * Return the name of this file
 262          *
 263          * @return string
 264          */
 265         public function getName() {
 266                 if ( !isset( $this->name ) ) {
 267                         $this->assertRepoDefined();
 268                         $this->name = $this->repo->getNameFromTitle( $this->title );
 269                 }
 270                 return $this->name;
 271         }
 272
 273         /**
 274          * Get the file extension, e.g. "svg"
 275          *
 276          * @return string
 277          */
 278         function getExtension() {
 279                 if ( !isset( $this->extension ) ) {
 280                         $n = strrpos( $this->getName(), '.' );
 281                         $this->extension = self::normalizeExtension(
 282                                 $n ? substr( $this->getName(), $n + 1 ) : '' );
 283                 }
 284                 return $this->extension;
 285         }
 286
 287         /**
 288          * Return the associated title object
 289          *
 290          * @return Title
 291          */
 292         public function getTitle() {
 293                 return $this->title;
 294         }
 295
 296         /**
 297          * Return the title used to find this file
 298          *
 299          * @return Title
 300          */
 301         public function getOriginalTitle() {
 302                 if ( $this->redirected ) {
 303                         return $this->getRedirectedTitle();
 304                 }
 305                 return $this->title;
 306         }
 307
 308         /**
 309          * Return the URL of the file
 310          *
 311          * @return string
 312          */
 313         public function getUrl() {
 314                 if ( !isset( $this->url ) ) {
 315                         $this->assertRepoDefined();
 316                         $this->url = $this->repo->getZoneUrl( 'public' ) . '/' . $this->getUrlRel();
 317                 }
 318                 return $this->url;
 319         }
 320
 321         /**
 322          * Return a fully-qualified URL to the file.
 323          * Upload URL paths _may or may not_ be fully qualified, so
 324          * we check. Local paths are assumed to belong on $wgServer.
 325          *
 326          * @return String
 327          */
 328         public function getFullUrl() {
 329                 return wfExpandUrl( $this->getUrl(), PROTO_RELATIVE );
 330         }
 331
 332         /**
 333          * @return string
 334          */
 335         public function getCanonicalUrl() {
 336                 return wfExpandUrl( $this->getUrl(), PROTO_CANONICAL );
 337         }
 338
 339         /**
 340          * @return string
 341          */
 342         function getViewURL() {
 343                 if ( $this->mustRender() ) {
 344                         if ( $this->canRender() ) {
 345                                 return $this->createThumb( $this->getWidth() );
 346                         } else {
 347                                 wfDebug( __METHOD__.': supposed to render ' . $this->getName() .
 348                                         ' (' . $this->getMimeType() . "), but can't!\n" );
 349                                 return $this->getURL(); #hm... return NULL?
 350                         }
 351                 } else {
 352                         return $this->getURL();
 353                 }
 354         }
 355
 356         /**
 357          * Return the storage path to the file. Note that this does
 358          * not mean that a file actually exists under that location.
 359          *
 360          * This path depends on whether directory hashing is active or not,
 361          * i.e. whether the files are all found in the same directory,
 362          * or in hashed paths like /images/3/3c.
 363          *
 364          * Most callers don't check the return value, but ForeignAPIFile::getPath
 365          * returns false.
 366          *
 367          * @return string|bool ForeignAPIFile::getPath can return false
 368         */
 369         public function getPath() {
 370                 if ( !isset( $this->path ) ) {
 371                         $this->assertRepoDefined();
 372                         $this->path = $this->repo->getZonePath( 'public' ) . '/' . $this->getRel();
 373                 }
 374                 return $this->path;
 375         }
 376
 377         /**
 378          * Get an FS copy or original of this file and return the path.
 379          * Returns false on failure. Callers must not alter the file.
 380          * Temporary files are cleared automatically.
 381          *
 382          * @return string|bool False on failure
 383          */
 384         public function getLocalRefPath() {
 385                 $this->assertRepoDefined();
 386                 if ( !isset( $this->fsFile ) ) {
 387                         $this->fsFile = $this->repo->getLocalReference( $this->getPath() );
 388                         if ( !$this->fsFile ) {
 389                                 $this->fsFile = false; // null => false; cache negative hits
 390                         }
 391                 }
 392                 return ( $this->fsFile )
 393                         ? $this->fsFile->getPath()
 394                         : false;
 395         }
 396
 397         /**
 398          * Return the width of the image. Returns false if the width is unknown
 399          * or undefined.
 400          *
 401          * STUB
 402          * Overridden by LocalFile, UnregisteredLocalFile
 403          *
 404          * @param $page int
 405          *
 406          * @return number
 407          */
 408         public function getWidth( $page = 1 ) {
 409                 return false;
 410         }
 411
 412         /**
 413          * Return the height of the image. Returns false if the height is unknown
 414          * or undefined
 415          *
 416          * STUB
 417          * Overridden by LocalFile, UnregisteredLocalFile
 418          *
 419          * @param $page int
 420          *
 421          * @return bool|number False on failure
 422          */
 423         public function getHeight( $page = 1 ) {
 424                 return false;
 425         }
 426
 427         /**
 428          * Returns ID or name of user who uploaded the file
 429          * STUB
 430          *
 431          * @param $type string 'text' or 'id'
 432          *
 433          * @return string|int
 434          */
 435         public function getUser( $type = 'text' ) {
 436                 return null;
 437         }
 438
 439         /**
 440          * Get the duration of a media file in seconds
 441          *
 442          * @return number
 443          */
 444         public function getLength() {
 445                 $handler = $this->getHandler();
 446                 if ( $handler ) {
 447                         return $handler->getLength( $this );
 448                 } else {
 449                         return 0;
 450                 }
 451         }
 452
 453         /**
 454          * Return true if the file is vectorized
 455          *
 456          * @return bool
 457          */
 458         public function isVectorized() {
 459                 $handler = $this->getHandler();
 460                 if ( $handler ) {
 461                         return $handler->isVectorized( $this );
 462                 } else {
 463                         return false;
 464                 }
 465         }
 466
 467         /**
 468          * Get handler-specific metadata
 469          * Overridden by LocalFile, UnregisteredLocalFile
 470          * STUB
 471          * @return bool
 472          */
 473         public function getMetadata() {
 474                 return false;
 475         }
 476
 477         /**
 478         * get versioned metadata
 479         *
 480         * @param $metadata Mixed Array or String of (serialized) metadata
 481         * @param $version integer version number.
 482         * @return Array containing metadata, or what was passed to it on fail (unserializing if not array)
 483         */
 484         public function convertMetadataVersion($metadata, $version) {
 485                 $handler = $this->getHandler();
 486                 if ( !is_array( $metadata ) ) {
 487                         // Just to make the return type consistent
 488                         $metadata = unserialize( $metadata );
 489                 }
 490                 if ( $handler ) {
 491                         return $handler->convertMetadataVersion( $metadata, $version );
 492                 } else {
 493                         return $metadata;
 494                 }
 495         }
 496
 497         /**
 498          * Return the bit depth of the file
 499          * Overridden by LocalFile
 500          * STUB
 501          * @return int
 502          */
 503         public function getBitDepth() {
 504                 return 0;
 505         }
 506
 507         /**
 508          * Return the size of the image file, in bytes
 509          * Overridden by LocalFile, UnregisteredLocalFile
 510          * STUB
 511          * @return bool
 512          */
 513         public function getSize() {
 514                 return false;
 515         }
 516
 517         /**
 518          * Returns the mime type of the file.
 519          * Overridden by LocalFile, UnregisteredLocalFile
 520          * STUB
 521          *
 522          * @return string
 523          */
 524         function getMimeType() {
 525                 return 'unknown/unknown';
 526         }
 527
 528         /**
 529          * Return the type of the media in the file.
 530          * Use the value returned by this function with the MEDIATYPE_xxx constants.
 531          * Overridden by LocalFile,
 532          * STUB
 533          * @return string
 534          */
 535         function getMediaType() {
 536                 return MEDIATYPE_UNKNOWN;
 537         }
 538
 539         /**
 540          * Checks if the output of transform() for this file is likely
 541          * to be valid. If this is false, various user elements will
 542          * display a placeholder instead.
 543          *
 544          * Currently, this checks if the file is an image format
 545          * that can be converted to a format
 546          * supported by all browsers (namely GIF, PNG and JPEG),
 547          * or if it is an SVG image and SVG conversion is enabled.
 548          *
 549          * @return bool
 550          */
 551         function canRender() {
 552                 if ( !isset( $this->canRender ) ) {
 553                         $this->canRender = $this->getHandler() && $this->handler->canRender( $this );
 554                 }
 555                 return $this->canRender;
 556         }
 557
 558         /**
 559          * Accessor for __get()
 560          * @return bool
 561          */
 562         protected function getCanRender() {
 563                 return $this->canRender();
 564         }
 565
 566         /**
 567          * Return true if the file is of a type that can't be directly
 568          * rendered by typical browsers and needs to be re-rasterized.
 569          *
 570          * This returns true for everything but the bitmap types
 571          * supported by all browsers, i.e. JPEG; GIF and PNG. It will
 572          * also return true for any non-image formats.
 573          *
 574          * @return bool
 575          */
 576         function mustRender() {
 577                 return $this->getHandler() && $this->handler->mustRender( $this );
 578         }
 579
 580         /**
 581          * Alias for canRender()
 582          *
 583          * @return bool
 584          */
 585         function allowInlineDisplay() {
 586                 return $this->canRender();
 587         }
 588
 589         /**
 590          * Determines if this media file is in a format that is unlikely to
 591          * contain viruses or malicious content. It uses the global
 592          * $wgTrustedMediaFormats list to determine if the file is safe.
 593          *
 594          * This is used to show a warning on the description page of non-safe files.
 595          * It may also be used to disallow direct [[media:...]] links to such files.
 596          *
 597          * Note that this function will always return true if allowInlineDisplay()
 598          * or isTrustedFile() is true for this file.
 599          *
 600          * @return bool
 601          */
 602         function isSafeFile() {
 603                 if ( !isset( $this->isSafeFile ) ) {
 604                         $this->isSafeFile = $this->_getIsSafeFile();
 605                 }
 606                 return $this->isSafeFile;
 607         }
 608
 609         /**
 610          * Accessor for __get()
 611          *
 612          * @return bool
 613          */
 614         protected function getIsSafeFile() {
 615                 return $this->isSafeFile();
 616         }
 617
 618         /**
 619          * Uncached accessor
 620          *
 621          * @return bool
 622          */
 623         protected function _getIsSafeFile() {
 624                 global $wgTrustedMediaFormats;
 625
 626                 if ( $this->allowInlineDisplay() ) {
 627                         return true;
 628                 }
 629                 if ($this->isTrustedFile()) {
 630                         return true;
 631                 }
 632
 633                 $type = $this->getMediaType();
 634                 $mime = $this->getMimeType();
 635                 #wfDebug("LocalFile::isSafeFile: type= $type, mime= $mime\n");
 636
 637                 if ( !$type || $type === MEDIATYPE_UNKNOWN ) {
 638                         return false; #unknown type, not trusted
 639                 }
 640                 if ( in_array( $type, $wgTrustedMediaFormats ) ) {
 641                         return true;
 642                 }
 643
 644                 if ( $mime === "unknown/unknown" ) {
 645                         return false; #unknown type, not trusted
 646                 }
 647                 if ( in_array( $mime, $wgTrustedMediaFormats) ) {
 648                         return true;
 649                 }
 650
 651                 return false;
 652         }
 653
 654         /**
 655          * Returns true if the file is flagged as trusted. Files flagged that way
 656          * can be linked to directly, even if that is not allowed for this type of
 657          * file normally.
 658          *
 659          * This is a dummy function right now and always returns false. It could be
 660          * implemented to extract a flag from the database. The trusted flag could be
 661          * set on upload, if the user has sufficient privileges, to bypass script-
 662          * and html-filters. It may even be coupled with cryptographics signatures
 663          * or such.
 664          *
 665          * @return bool
 666          */
 667         function isTrustedFile() {
 668                 #this could be implemented to check a flag in the database,
 669                 #look for signatures, etc
 670                 return false;
 671         }
 672
 673         /**
 674          * Returns true if file exists in the repository.
 675          *
 676          * Overridden by LocalFile to avoid unnecessary stat calls.
 677          *
 678          * @return boolean Whether file exists in the repository.
 679          */
 680         public function exists() {
 681                 return $this->getPath() && $this->repo->fileExists( $this->path );
 682         }
 683
 684         /**
 685          * Returns true if file exists in the repository and can be included in a page.
 686          * It would be unsafe to include private images, making public thumbnails inadvertently
 687          *
 688          * @return boolean Whether file exists in the repository and is includable.
 689          */
 690         public function isVisible() {
 691                 return $this->exists();
 692         }
 693
 694         /**
 695          * @return string
 696          */
 697         function getTransformScript() {
 698                 if ( !isset( $this->transformScript ) ) {
 699                         $this->transformScript = false;
 700                         if ( $this->repo ) {
 701                                 $script = $this->repo->getThumbScriptUrl();
 702                                 if ( $script ) {
 703                                         $this->transformScript = "$script?f=" . urlencode( $this->getName() );
 704                                 }
 705                         }
 706                 }
 707                 return $this->transformScript;
 708         }
 709
 710         /**
 711          * Get a ThumbnailImage which is the same size as the source
 712          *
 713          * @param $handlerParams array
 714          *
 715          * @return string
 716          */
 717         function getUnscaledThumb( $handlerParams = array() ) {
 718                 $hp =& $handlerParams;
 719                 $page = isset( $hp['page'] ) ? $hp['page'] : false;
 720                 $width = $this->getWidth( $page );
 721                 if ( !$width ) {
 722                         return $this->iconThumb();
 723                 }
 724                 $hp['width'] = $width;
 725                 return $this->transform( $hp );
 726         }
 727
 728         /**
 729          * Return the file name of a thumbnail with the specified parameters
 730          *
 731          * @param $params Array: handler-specific parameters
 732          * @private -ish
 733          *
 734          * @return string
 735          */
 736         function thumbName( $params ) {
 737                 return $this->generateThumbName( $this->getName(), $params );
 738         }
 739
 740         /**
 741          * Generate a thumbnail file name from a name and specified parameters
 742          *
 743          * @param string $name
 744          * @param array $params Parameters which will be passed to MediaHandler::makeParamString
 745          *
 746          * @return string
 747          */
 748         function generateThumbName( $name, $params ) {
 749                 if ( !$this->getHandler() ) {
 750                         return null;
 751                 }
 752                 $extension = $this->getExtension();
 753                 list( $thumbExt, $thumbMime ) = $this->handler->getThumbType(
 754                         $extension, $this->getMimeType(), $params );
 755                 $thumbName = $this->handler->makeParamString( $params ) . '-' . $name;
 756                 if ( $thumbExt != $extension ) {
 757                         $thumbName .= ".$thumbExt";
 758                 }
 759                 return $thumbName;
 760         }
 761
 762         /**
 763          * Create a thumbnail of the image having the specified width/height.
 764          * The thumbnail will not be created if the width is larger than the
 765          * image's width. Let the browser do the scaling in this case.
 766          * The thumbnail is stored on disk and is only computed if the thumbnail
 767          * file does not exist OR if it is older than the image.
 768          * Returns the URL.
 769          *
 770          * Keeps aspect ratio of original image. If both width and height are
 771          * specified, the generated image will be no bigger than width x height,
 772          * and will also have correct aspect ratio.
 773          *
 774          * @param $width Integer: maximum width of the generated thumbnail
 775          * @param $height Integer: maximum height of the image (optional)
 776          *
 777          * @return string
 778          */
 779         public function createThumb( $width, $height = -1 ) {
 780                 $params = array( 'width' => $width );
 781                 if ( $height != -1 ) {
 782                         $params['height'] = $height;
 783                 }
 784                 $thumb = $this->transform( $params );
 785                 if ( is_null( $thumb ) || $thumb->isError() ) {
 786                         return '';
 787                 }
 788                 return $thumb->getUrl();
 789         }
 790
 791         /**
 792          * Return either a MediaTransformError or placeholder thumbnail (if $wgIgnoreImageErrors)
 793          *
 794          * @param $thumbPath string Thumbnail storage path
 795          * @param $thumbUrl string Thumbnail URL
 796          * @param $params Array
 797          * @param $flags integer
 798          * @return MediaTransformOutput
 799          */
 800         protected function transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags ) {
 801                 global $wgIgnoreImageErrors;
 802
 803                 if ( $wgIgnoreImageErrors && !( $flags & self::RENDER_NOW ) ) {
 804                         return $this->handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
 805                 } else {
 806                         return new MediaTransformError( 'thumbnail_error',
 807                                 $params['width'], 0, wfMsg( 'thumbnail-dest-create' ) );
 808                 }
 809         }
 810
 811         /**
 812          * Transform a media file
 813          *
 814          * @param $params Array: an associative array of handler-specific parameters.
 815          *                Typical keys are width, height and page.
 816          * @param $flags Integer: a bitfield, may contain self::RENDER_NOW to force rendering
 817          * @return MediaTransformOutput|bool False on failure
 818          */
 819         function transform( $params, $flags = 0 ) {
 820                 global $wgUseSquid, $wgIgnoreImageErrors, $wgThumbnailEpoch;
 821
 822                 wfProfileIn( __METHOD__ );
 823                 do {
 824                         if ( !$this->canRender() ) {
 825                                 $thumb = $this->iconThumb();
 826                                 break; // not a bitmap or renderable image, don't try
 827                         }
 828
 829                         // Get the descriptionUrl to embed it as comment into the thumbnail. Bug 19791.
 830                         $descriptionUrl = $this->getDescriptionUrl();
 831                         if ( $descriptionUrl ) {
 832                                 $params['descriptionUrl'] = wfExpandUrl( $descriptionUrl, PROTO_CANONICAL );
 833                         }
 834
 835                         $script = $this->getTransformScript();
 836                         if ( $script && !( $flags & self::RENDER_NOW ) ) {
 837                                 // Use a script to transform on client request, if possible
 838                                 $thumb = $this->handler->getScriptedTransform( $this, $script, $params );
 839                                 if ( $thumb ) {
 840                                         break;
 841                                 }
 842                         }
 843
 844                         $normalisedParams = $params;
 845                         $this->handler->normaliseParams( $this, $normalisedParams );
 846
 847                         $thumbName = $this->thumbName( $normalisedParams );
 848                         $thumbUrl = $this->getThumbUrl( $thumbName );
 849                         $thumbPath = $this->getThumbPath( $thumbName ); // final thumb path
 850
 851                         if ( $this->repo ) {
 852                                 // Defer rendering if a 404 handler is set up...
 853                                 if ( $this->repo->canTransformVia404() && !( $flags & self::RENDER_NOW ) ) {
 854                                         wfDebug( __METHOD__ . " transformation deferred." );
 855                                         // XXX: Pass in the storage path even though we are not rendering anything
 856                                         // and the path is supposed to be an FS path. This is due to getScalerType()
 857                                         // getting called on the path and clobbering $thumb->getUrl() if it's false.
 858                                         $thumb = $this->handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
 859                                         break;
 860                                 }
 861                                 // Clean up broken thumbnails as needed
 862                                 $this->migrateThumbFile( $thumbName );
 863                                 // Check if an up-to-date thumbnail already exists...
 864                                 wfDebug( __METHOD__.": Doing stat for $thumbPath\n" );
 865                                 if ( $this->repo->fileExists( $thumbPath ) && !( $flags & self::RENDER_FORCE ) ) {
 866                                         $timestamp = $this->repo->getFileTimestamp( $thumbPath );
 867                                         if ( $timestamp !== false && $timestamp >= $wgThumbnailEpoch ) {
 868                                                 // XXX: Pass in the storage path even though we are not rendering anything
 869                                                 // and the path is supposed to be an FS path. This is due to getScalerType()
 870                                                 // getting called on the path and clobbering $thumb->getUrl() if it's false.
 871                                                 $thumb = $this->handler->getTransform( $this, $thumbPath, $thumbUrl, $params );
 872                                                 $thumb->setStoragePath( $thumbPath );
 873                                                 break;
 874                                         }
 875                                 } elseif ( $flags & self::RENDER_FORCE ) {
 876                                         wfDebug( __METHOD__ . " forcing rendering per flag File::RENDER_FORCE\n" );
 877                                 }
 878                         }
 879
 880                         // If the backend is ready-only, don't keep generating thumbnails
 881                         // only to return transformation errors, just return the error now.
 882                         if ( $this->repo->getReadOnlyReason() !== false ) {
 883                                 $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags );
 884                                 break;
 885                         }
 886
 887                         // Create a temp FS file with the same extension and the thumbnail
 888                         $thumbExt = FileBackend::extensionFromPath( $thumbPath );
 889                         $tmpFile = TempFSFile::factory( 'transform_', $thumbExt );
 890                         if ( !$tmpFile ) {
 891                                 $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags );
 892                                 break;
 893                         }
 894                         $tmpThumbPath = $tmpFile->getPath(); // path of 0-byte temp file
 895
 896                         // Actually render the thumbnail...
 897                         $thumb = $this->handler->doTransform( $this, $tmpThumbPath, $thumbUrl, $params );
 898                         $tmpFile->bind( $thumb ); // keep alive with $thumb
 899
 900                         if ( !$thumb ) { // bad params?
 901                                 $thumb = null;
 902                         } elseif ( $thumb->isError() ) { // transform error
 903                                 $this->lastError = $thumb->toText();
 904                                 // Ignore errors if requested
 905                                 if ( $wgIgnoreImageErrors && !( $flags & self::RENDER_NOW ) ) {
 906                                         $thumb = $this->handler->getTransform( $this, $tmpThumbPath, $thumbUrl, $params );
 907                                 }
 908                         } elseif ( $this->repo && $thumb->hasFile() && !$thumb->fileIsSource() ) {
 909                                 // Copy the thumbnail from the file system into storage...
 910                                 $status = $this->repo->quickImport( $tmpThumbPath, $thumbPath );
 911                                 if ( $status->isOK() ) {
 912                                         $thumb->setStoragePath( $thumbPath );
 913                                 } else {
 914                                         $thumb = $this->transformErrorOutput( $thumbPath, $thumbUrl, $params, $flags );
 915                                 }
 916                                 // Give extensions a chance to do something with this thumbnail...
 917                                 wfRunHooks( 'FileTransformed', array( $this, $thumb, $tmpThumbPath, $thumbPath ) );
 918                         }
 919
 920                         // Purge. Useful in the event of Core -> Squid connection failure or squid
 921                         // purge collisions from elsewhere during failure. Don't keep triggering for
 922                         // "thumbs" which have the main image URL though (bug 13776)
 923                         if ( $wgUseSquid ) {
 924                                 if ( !$thumb || $thumb->isError() || $thumb->getUrl() != $this->getURL() ) {
 925                                         SquidUpdate::purge( array( $thumbUrl ) );
 926                                 }
 927                         }
 928                 } while ( false );
 929
 930                 wfProfileOut( __METHOD__ );
 931                 return is_object( $thumb ) ? $thumb : false;
 932         }
 933
 934         /**
 935          * Hook into transform() to allow migration of thumbnail files
 936          * STUB
 937          * Overridden by LocalFile
 938          */
 939         function migrateThumbFile( $thumbName ) {}
 940
 941         /**
 942          * Get a MediaHandler instance for this file
 943          *
 944          * @return MediaHandler
 945          */
 946         function getHandler() {
 947                 if ( !isset( $this->handler ) ) {
 948                         $this->handler = MediaHandler::getHandler( $this->getMimeType() );
 949                 }
 950                 return $this->handler;
 951         }
 952
 953         /**
 954          * Get a ThumbnailImage representing a file type icon
 955          *
 956          * @return ThumbnailImage
 957          */
 958         function iconThumb() {
 959                 global $wgStylePath, $wgStyleDirectory;
 960
 961                 $try = array( 'fileicon-' . $this->getExtension() . '.png', 'fileicon.png' );
 962                 foreach ( $try as $icon ) {
 963                         $path = '/common/images/icons/' . $icon;
 964                         $filepath = $wgStyleDirectory . $path;
 965                         if ( file_exists( $filepath ) ) { // always FS
 966                                 return new ThumbnailImage( $this, $wgStylePath . $path, 120, 120 );
 967                         }
 968                 }
 969                 return null;
 970         }
 971
 972         /**
 973          * Get last thumbnailing error.
 974          * Largely obsolete.
 975          */
 976         function getLastError() {
 977                 return $this->lastError;
 978         }
 979
 980         /**
 981          * Get all thumbnail names previously generated for this file
 982          * STUB
 983          * Overridden by LocalFile
 984          * @return array
 985          */
 986         function getThumbnails() {
 987                 return array();
 988         }
 989
 990         /**
 991          * Purge shared caches such as thumbnails and DB data caching
 992          * STUB
 993          * Overridden by LocalFile
 994          * @param $options Array Options, which include:
 995          *     'forThumbRefresh' : The purging is only to refresh thumbnails
 996          */
 997         function purgeCache( $options = array() ) {}
 998
 999         /**
1000          * Purge the file description page, but don't go after
1001          * pages using the file. Use when modifying file history
1002          * but not the current data.
1003          */
1004         function purgeDescription() {
1005                 $title = $this->getTitle();
1006                 if ( $title ) {
1007                         $title->invalidateCache();
1008                         $title->purgeSquid();
1009                 }
1010         }
1011
1012         /**
1013          * Purge metadata and all affected pages when the file is created,
1014          * deleted, or majorly updated.
1015          */
1016         function purgeEverything() {
1017                 // Delete thumbnails and refresh file metadata cache
1018                 $this->purgeCache();
1019                 $this->purgeDescription();
1020
1021                 // Purge cache of all pages using this file
1022                 $title = $this->getTitle();
1023                 if ( $title ) {
1024                         $update = new HTMLCacheUpdate( $title, 'imagelinks' );
1025                         $update->doUpdate();
1026                 }
1027         }
1028
1029         /**
1030          * Return a fragment of the history of file.
1031          *
1032          * STUB
1033          * @param $limit integer Limit of rows to return
1034          * @param $start string timestamp Only revisions older than $start will be returned
1035          * @param $end string timestamp Only revisions newer than $end will be returned
1036          * @param $inc bool Include the endpoints of the time range
1037          *
1038          * @return array
1039          */
1040         function getHistory( $limit = null, $start = null, $end = null, $inc=true ) {
1041                 return array();
1042         }
1043
1044         /**
1045          * Return the history of this file, line by line. Starts with current version,
1046          * then old versions. Should return an object similar to an image/oldimage
1047          * database row.
1048          *
1049          * STUB
1050          * Overridden in LocalFile
1051          * @return bool
1052          */
1053         public function nextHistoryLine() {
1054                 return false;
1055         }
1056
1057         /**
1058          * Reset the history pointer to the first element of the history.
1059          * Always call this function after using nextHistoryLine() to free db resources
1060          * STUB
1061          * Overridden in LocalFile.
1062          */
1063         public function resetHistory() {}
1064
1065         /**
1066          * Get the filename hash component of the directory including trailing slash,
1067          * e.g. f/fa/
1068          * If the repository is not hashed, returns an empty string.
1069          *
1070          * @return string
1071          */
1072         function getHashPath() {
1073                 if ( !isset( $this->hashPath ) ) {
1074                         $this->assertRepoDefined();
1075                         $this->hashPath = $this->repo->getHashPath( $this->getName() );
1076                 }
1077                 return $this->hashPath;
1078         }
1079
1080         /**
1081          * Get the path of the file relative to the public zone root.
1082          * This function is overriden in OldLocalFile to be like getArchiveRel().
1083          *
1084          * @return string
1085          */
1086         function getRel() {
1087                 return $this->getHashPath() . $this->getName();
1088         }
1089
1090         /**
1091          * Get the path of an archived file relative to the public zone root
1092          *
1093          * @param $suffix bool|string if not false, the name of an archived thumbnail file
1094          *
1095          * @return string
1096          */
1097         function getArchiveRel( $suffix = false ) {
1098                 $path = 'archive/' . $this->getHashPath();
1099                 if ( $suffix === false ) {
1100                         $path = substr( $path, 0, -1 );
1101                 } else {
1102                         $path .= $suffix;
1103                 }
1104                 return $path;
1105         }
1106
1107         /**
1108          * Get the path, relative to the thumbnail zone root, of the
1109          * thumbnail directory or a particular file if $suffix is specified
1110          *
1111          * @param $suffix bool|string if not false, the name of a thumbnail file
1112          *
1113          * @return string
1114          */
1115         function getThumbRel( $suffix = false ) {
1116                 $path = $this->getRel();
1117                 if ( $suffix !== false ) {
1118                         $path .= '/' . $suffix;
1119                 }
1120                 return $path;
1121         }
1122
1123         /**
1124          * Get urlencoded path of the file relative to the public zone root.
1125          * This function is overriden in OldLocalFile to be like getArchiveUrl().
1126          *
1127          * @return string
1128          */
1129         function getUrlRel() {
1130                 return $this->getHashPath() . rawurlencode( $this->getName() );
1131         }
1132
1133         /**
1134          * Get the path, relative to the thumbnail zone root, for an archived file's thumbs directory
1135          * or a specific thumb if the $suffix is given.
1136          *
1137          * @param $archiveName string the timestamped name of an archived image
1138          * @param $suffix bool|string if not false, the name of a thumbnail file
1139          *
1140          * @return string
1141          */
1142         function getArchiveThumbRel( $archiveName, $suffix = false ) {
1143                 $path = 'archive/' . $this->getHashPath() . $archiveName . "/";
1144                 if ( $suffix === false ) {
1145                         $path = substr( $path, 0, -1 );
1146                 } else {
1147                         $path .= $suffix;
1148                 }
1149                 return $path;
1150         }
1151
1152         /**
1153          * Get the path of the archived file.
1154          *
1155          * @param $suffix bool|string if not false, the name of an archived file.
1156          *
1157          * @return string
1158          */
1159         function getArchivePath( $suffix = false ) {
1160                 $this->assertRepoDefined();
1161                 return $this->repo->getZonePath( 'public' ) . '/' . $this->getArchiveRel( $suffix );
1162         }
1163
1164         /**
1165          * Get the path of an archived file's thumbs, or a particular thumb if $suffix is specified
1166          *
1167          * @param $archiveName string the timestamped name of an archived image
1168          * @param $suffix bool|string if not false, the name of a thumbnail file
1169          *
1170          * @return string
1171          */
1172         function getArchiveThumbPath( $archiveName, $suffix = false ) {
1173                 $this->assertRepoDefined();
1174                 return $this->repo->getZonePath( 'thumb' ) . '/' .
1175                         $this->getArchiveThumbRel( $archiveName, $suffix );
1176         }
1177
1178         /**
1179          * Get the path of the thumbnail directory, or a particular file if $suffix is specified
1180          *
1181          * @param $suffix bool|string if not false, the name of a thumbnail file
1182          *
1183          * @return string
1184          */
1185         function getThumbPath( $suffix = false ) {
1186                 $this->assertRepoDefined();
1187                 return $this->repo->getZonePath( 'thumb' ) . '/' . $this->getThumbRel( $suffix );
1188         }
1189
1190         /**
1191          * Get the URL of the archive directory, or a particular file if $suffix is specified
1192          *
1193          * @param $suffix bool|string if not false, the name of an archived file
1194          *
1195          * @return string
1196          */
1197         function getArchiveUrl( $suffix = false ) {
1198                 $this->assertRepoDefined();
1199                 $path = $this->repo->getZoneUrl( 'public' ) . '/archive/' . $this->getHashPath();
1200                 if ( $suffix === false ) {
1201                         $path = substr( $path, 0, -1 );
1202                 } else {
1203                         $path .= rawurlencode( $suffix );
1204                 }
1205                 return $path;
1206         }
1207
1208         /**
1209          * Get the URL of the archived file's thumbs, or a particular thumb if $suffix is specified
1210          *
1211          * @param $archiveName string the timestamped name of an archived image
1212          * @param $suffix bool|string if not false, the name of a thumbnail file
1213          *
1214          * @return string
1215          */
1216         function getArchiveThumbUrl( $archiveName, $suffix = false ) {
1217                 $this->assertRepoDefined();
1218                 $path = $this->repo->getZoneUrl( 'thumb' ) . '/archive/' .
1219                         $this->getHashPath() . rawurlencode( $archiveName ) . "/";
1220                 if ( $suffix === false ) {
1221                         $path = substr( $path, 0, -1 );
1222                 } else {
1223                         $path .= rawurlencode( $suffix );
1224                 }
1225                 return $path;
1226         }
1227
1228         /**
1229          * Get the URL of the thumbnail directory, or a particular file if $suffix is specified
1230          *
1231          * @param $suffix bool|string if not false, the name of a thumbnail file
1232          *
1233          * @return string path
1234          */
1235         function getThumbUrl( $suffix = false ) {
1236                 $this->assertRepoDefined();
1237                 $path = $this->repo->getZoneUrl( 'thumb' ) . '/' . $this->getUrlRel();
1238                 if ( $suffix !== false ) {
1239                         $path .= '/' . rawurlencode( $suffix );
1240                 }
1241                 return $path;
1242         }
1243
1244         /**
1245          * Get the public zone virtual URL for a current version source file
1246          *
1247          * @param $suffix bool|string if not false, the name of a thumbnail file
1248          *
1249          * @return string
1250          */
1251         function getVirtualUrl( $suffix = false ) {
1252                 $this->assertRepoDefined();
1253                 $path = $this->repo->getVirtualUrl() . '/public/' . $this->getUrlRel();
1254                 if ( $suffix !== false ) {
1255                         $path .= '/' . rawurlencode( $suffix );
1256                 }
1257                 return $path;
1258         }
1259
1260         /**
1261          * Get the public zone virtual URL for an archived version source file
1262          *
1263          * @param $suffix bool|string if not false, the name of a thumbnail file
1264          *
1265          * @return string
1266          */
1267         function getArchiveVirtualUrl( $suffix = false ) {
1268                 $this->assertRepoDefined();
1269                 $path = $this->repo->getVirtualUrl() . '/public/archive/' . $this->getHashPath();
1270                 if ( $suffix === false ) {
1271                         $path = substr( $path, 0, -1 );
1272                 } else {
1273                         $path .= rawurlencode( $suffix );
1274                 }
1275                 return $path;
1276         }
1277
1278         /**
1279          * Get the virtual URL for a thumbnail file or directory
1280          *
1281          * @param $suffix bool|string if not false, the name of a thumbnail file
1282          *
1283          * @return string
1284          */
1285         function getThumbVirtualUrl( $suffix = false ) {
1286                 $this->assertRepoDefined();
1287                 $path = $this->repo->getVirtualUrl() . '/thumb/' . $this->getUrlRel();
1288                 if ( $suffix !== false ) {
1289                         $path .= '/' . rawurlencode( $suffix );
1290                 }
1291                 return $path;
1292         }
1293
1294         /**
1295          * @return bool
1296          */
1297         function isHashed() {
1298                 $this->assertRepoDefined();
1299                 return (bool)$this->repo->getHashLevels();
1300         }
1301
1302         /**
1303          * @throws MWException
1304          */
1305         function readOnlyError() {
1306                 throw new MWException( get_class($this) . ': write operations are not supported' );
1307         }
1308
1309         /**
1310          * Record a file upload in the upload log and the image table
1311          * STUB
1312          * Overridden by LocalFile
1313          * @param $oldver
1314          * @param $desc
1315          * @param $license string
1316          * @param $copyStatus string
1317          * @param $source string
1318          * @param $watch bool
1319          */
1320         function recordUpload( $oldver, $desc, $license = '', $copyStatus = '', $source = '', $watch = false ) {
1321                 $this->readOnlyError();
1322         }
1323
1324         /**
1325          * Move or copy a file to its public location. If a file exists at the
1326          * destination, move it to an archive. Returns a FileRepoStatus object with
1327          * the archive name in the "value" member on success.
1328          *
1329          * The archive name should be passed through to recordUpload for database
1330          * registration.
1331          *
1332          * @param $srcPath String: local filesystem path to the source image
1333          * @param $flags Integer: a bitwise combination of:
1334          *     File::DELETE_SOURCE    Delete the source file, i.e. move
1335          *         rather than copy
1336          * @return FileRepoStatus object. On success, the value member contains the
1337          *     archive name, or an empty string if it was a new file.
1338          *
1339          * STUB
1340          * Overridden by LocalFile
1341          */
1342         function publish( $srcPath, $flags = 0 ) {
1343                 $this->readOnlyError();
1344         }
1345
1346         /**
1347          * @return bool
1348          */
1349         function formatMetadata() {
1350                 if ( !$this->getHandler() ) {
1351                         return false;
1352                 }
1353                 return $this->getHandler()->formatMetadata( $this, $this->getMetadata() );
1354         }
1355
1356         /**
1357          * Returns true if the file comes from the local file repository.
1358          *
1359          * @return bool
1360          */
1361         function isLocal() {
1362                 return $this->repo && $this->repo->isLocal();
1363         }
1364
1365         /**
1366          * Returns the name of the repository.
1367          *
1368          * @return string
1369          */
1370         function getRepoName() {
1371                 return $this->repo ? $this->repo->getName() : 'unknown';
1372         }
1373
1374         /**
1375          * Returns the repository
1376          *
1377          * @return FileRepo|bool
1378          */
1379         function getRepo() {
1380                 return $this->repo;
1381         }
1382
1383         /**
1384          * Returns true if the image is an old version
1385          * STUB
1386          *
1387          * @return bool
1388          */
1389         function isOld() {
1390                 return false;
1391         }
1392
1393         /**
1394          * Is this file a "deleted" file in a private archive?
1395          * STUB
1396          *
1397          * @param $field
1398          *
1399          * @return bool
1400          */
1401         function isDeleted( $field ) {
1402                 return false;
1403         }
1404
1405         /**
1406          * Return the deletion bitfield
1407          * STUB
1408          * @return int
1409          */
1410         function getVisibility() {
1411                 return 0;
1412         }
1413
1414         /**
1415          * Was this file ever deleted from the wiki?
1416          *
1417          * @return bool
1418          */
1419         function wasDeleted() {
1420                 $title = $this->getTitle();
1421                 return $title && $title->isDeletedQuick();
1422         }
1423
1424         /**
1425          * Move file to the new title
1426          *
1427          * Move current, old version and all thumbnails
1428          * to the new filename. Old file is deleted.
1429          *
1430          * Cache purging is done; checks for validity
1431          * and logging are caller's responsibility
1432          *
1433          * @param $target Title New file name
1434          * @return FileRepoStatus object.
1435          */
1436          function move( $target ) {
1437                 $this->readOnlyError();
1438          }
1439
1440         /**
1441          * Delete all versions of the file.
1442          *
1443          * Moves the files into an archive directory (or deletes them)
1444          * and removes the database rows.
1445          *
1446          * Cache purging is done; logging is caller's responsibility.
1447          *
1448          * @param $reason String
1449          * @param $suppress Boolean: hide content from sysops?
1450          * @return bool on success, false on some kind of failure
1451          * STUB
1452          * Overridden by LocalFile
1453          */
1454         function delete( $reason, $suppress = false ) {
1455                 $this->readOnlyError();
1456         }
1457
1458         /**
1459          * Restore all or specified deleted revisions to the given file.
1460          * Permissions and logging are left to the caller.
1461          *
1462          * May throw database exceptions on error.
1463          *
1464          * @param $versions array set of record ids of deleted items to restore,
1465          *                    or empty to restore all revisions.
1466          * @param $unsuppress bool remove restrictions on content upon restoration?
1467          * @return int|bool the number of file revisions restored if successful,
1468          *         or false on failure
1469          * STUB
1470          * Overridden by LocalFile
1471          */
1472         function restore( $versions = array(), $unsuppress = false ) {
1473                 $this->readOnlyError();
1474         }
1475
1476         /**
1477          * Returns 'true' if this file is a type which supports multiple pages,
1478          * e.g. DJVU or PDF. Note that this may be true even if the file in
1479          * question only has a single page.
1480          *
1481          * @return Bool
1482          */
1483         function isMultipage() {
1484                 return $this->getHandler() && $this->handler->isMultiPage( $this );
1485         }
1486
1487         /**
1488          * Returns the number of pages of a multipage document, or false for
1489          * documents which aren't multipage documents
1490          *
1491          * @return bool|int
1492          */
1493         function pageCount() {
1494                 if ( !isset( $this->pageCount ) ) {
1495                         if ( $this->getHandler() && $this->handler->isMultiPage( $this ) ) {
1496                                 $this->pageCount = $this->handler->pageCount( $this );
1497                         } else {
1498                                 $this->pageCount = false;
1499                         }
1500                 }
1501                 return $this->pageCount;
1502         }
1503
1504         /**
1505          * Calculate the height of a thumbnail using the source and destination width
1506          *
1507          * @param $srcWidth
1508          * @param $srcHeight
1509          * @param $dstWidth
1510          *
1511          * @return int
1512          */
1513         static function scaleHeight( $srcWidth, $srcHeight, $dstWidth ) {
1514                 // Exact integer multiply followed by division
1515                 if ( $srcWidth == 0 ) {
1516                         return 0;
1517                 } else {
1518                         return round( $srcHeight * $dstWidth / $srcWidth );
1519                 }
1520         }
1521
1522         /**
1523          * Get an image size array like that returned by getImageSize(), or false if it
1524          * can't be determined.
1525          *
1526          * @param $fileName String: The filename
1527          * @return Array
1528          */
1529         function getImageSize( $fileName ) {
1530                 if ( !$this->getHandler() ) {
1531                         return false;
1532                 }
1533                 return $this->handler->getImageSize( $this, $fileName );
1534         }
1535
1536         /**
1537          * Get the URL of the image description page. May return false if it is
1538          * unknown or not applicable.
1539          *
1540          * @return string
1541          */
1542         function getDescriptionUrl() {
1543                 if ( $this->repo ) {
1544                         return $this->repo->getDescriptionUrl( $this->getName() );
1545                 } else {
1546                         return false;
1547                 }
1548         }
1549
1550         /**
1551          * Get the HTML text of the description page, if available
1552          *
1553          * @return string
1554          */
1555         function getDescriptionText() {
1556                 global $wgMemc, $wgLang;
1557                 if ( !$this->repo || !$this->repo->fetchDescription ) {
1558                         return false;
1559                 }
1560                 $renderUrl = $this->repo->getDescriptionRenderUrl( $this->getName(), $wgLang->getCode() );
1561                 if ( $renderUrl ) {
1562                         if ( $this->repo->descriptionCacheExpiry > 0 ) {
1563                                 wfDebug("Attempting to get the description from cache...");
1564                                 $key = $this->repo->getLocalCacheKey( 'RemoteFileDescription', 'url', $wgLang->getCode(),
1565                                                                         $this->getName() );
1566                                 $obj = $wgMemc->get($key);
1567                                 if ($obj) {
1568                                         wfDebug("success!\n");
1569                                         return $obj;
1570                                 }
1571                                 wfDebug("miss\n");
1572                         }
1573                         wfDebug( "Fetching shared description from $renderUrl\n" );
1574                         $res = Http::get( $renderUrl );
1575                         if ( $res && $this->repo->descriptionCacheExpiry > 0 ) {
1576                                 $wgMemc->set( $key, $res, $this->repo->descriptionCacheExpiry );
1577                         }
1578                         return $res;
1579                 } else {
1580                         return false;
1581                 }
1582         }
1583
1584         /**
1585          * Get description of file revision
1586          * STUB
1587          *
1588          * @param $audience Integer: one of:
1589          *      File::FOR_PUBLIC       to be displayed to all users
1590          *      File::FOR_THIS_USER    to be displayed to the given user
1591          *      File::RAW              get the description regardless of permissions
1592          * @param $user User object to check for, only if FOR_THIS_USER is passed
1593          *              to the $audience parameter
1594          * @return string
1595          */
1596         function getDescription( $audience = self::FOR_PUBLIC, User $user = null ) {
1597                 return null;
1598         }
1599
1600         /**
1601          * Get the 14-character timestamp of the file upload
1602          *
1603          * @return string|bool TS_MW timestamp or false on failure
1604          */
1605         function getTimestamp() {
1606                 $this->assertRepoDefined();
1607                 return $this->repo->getFileTimestamp( $this->getPath() );
1608         }
1609
1610         /**
1611          * Get the SHA-1 base 36 hash of the file
1612          *
1613          * @return string
1614          */
1615         function getSha1() {
1616                 $this->assertRepoDefined();
1617                 return $this->repo->getFileSha1( $this->getPath() );
1618         }
1619
1620         /**
1621          * Get the deletion archive key, "<sha1>.<ext>"
1622          *
1623          * @return string
1624          */
1625         function getStorageKey() {
1626                 $hash = $this->getSha1();
1627                 if ( !$hash ) {
1628                         return false;
1629                 }
1630                 $ext = $this->getExtension();
1631                 $dotExt = $ext === '' ? '' : ".$ext";
1632                 return $hash . $dotExt;
1633         }
1634
1635         /**
1636          * Determine if the current user is allowed to view a particular
1637          * field of this file, if it's marked as deleted.
1638          * STUB
1639          * @param $field Integer
1640          * @param $user User object to check, or null to use $wgUser
1641          * @return Boolean
1642          */
1643         function userCan( $field, User $user = null ) {
1644                 return true;
1645         }
1646
1647         /**
1648          * Get an associative array containing information about a file in the local filesystem.
1649          *
1650          * @param $path String: absolute local filesystem path
1651          * @param $ext Mixed: the file extension, or true to extract it from the filename.
1652          *             Set it to false to ignore the extension.
1653          *
1654          * @return array
1655          */
1656         static function getPropsFromPath( $path, $ext = true ) {
1657                 wfDebug( __METHOD__.": Getting file info for $path\n" );
1658                 wfDeprecated( __METHOD__, '1.19' );
1659
1660                 $fsFile = new FSFile( $path );
1661                 return $fsFile->getProps();
1662         }
1663
1664         /**
1665          * Get a SHA-1 hash of a file in the local filesystem, in base-36 lower case
1666          * encoding, zero padded to 31 digits.
1667          *
1668          * 160 log 2 / log 36 = 30.95, so the 160-bit hash fills 31 digits in base 36
1669          * fairly neatly.
1670          *
1671          * @param $path string
1672          *
1673          * @return bool|string False on failure
1674          */
1675         static function sha1Base36( $path ) {
1676                 wfDeprecated( __METHOD__, '1.19' );
1677
1678                 $fsFile = new FSFile( $path );
1679                 return $fsFile->getSha1Base36();
1680         }
1681
1682         /**
1683          * @return string
1684          */
1685         function getLongDesc() {
1686                 $handler = $this->getHandler();
1687                 if ( $handler ) {
1688                         return $handler->getLongDesc( $this );
1689                 } else {
1690                         return MediaHandler::getGeneralLongDesc( $this );
1691                 }
1692         }
1693
1694         /**
1695          * @return string
1696          */
1697         function getShortDesc() {
1698                 $handler = $this->getHandler();
1699                 if ( $handler ) {
1700                         return $handler->getShortDesc( $this );
1701                 } else {
1702                         return MediaHandler::getGeneralShortDesc( $this );
1703                 }
1704         }
1705
1706         /**
1707          * @return string
1708          */
1709         function getDimensionsString() {
1710                 $handler = $this->getHandler();
1711                 if ( $handler ) {
1712                         return $handler->getDimensionsString( $this );
1713                 } else {
1714                         return '';
1715                 }
1716         }
1717
1718         /**
1719          * @return
1720          */
1721         function getRedirected() {
1722                 return $this->redirected;
1723         }
1724
1725         /**
1726          * @return Title
1727          */
1728         function getRedirectedTitle() {
1729                 if ( $this->redirected ) {
1730                         if ( !$this->redirectTitle ) {
1731                                 $this->redirectTitle = Title::makeTitle( NS_FILE, $this->redirected );
1732                         }
1733                         return $this->redirectTitle;
1734                 }
1735         }
1736
1737         /**
1738          * @param  $from
1739          * @return void
1740          */
1741         function redirectedFrom( $from ) {
1742                 $this->redirected = $from;
1743         }
1744
1745         /**
1746          * @return bool
1747          */
1748         function isMissing() {
1749                 return false;
1750         }
1751
1752         /**
1753          * Check if this file object is small and can be cached
1754          * @return boolean
1755          */
1756         public function isCacheable() {
1757                 return true;
1758         }
1759
1760         /**
1761          * Assert that $this->repo is set to a valid FileRepo instance
1762          * @throws MWException
1763          */
1764         protected function assertRepoDefined() {
1765                 if ( !( $this->repo instanceof $this->repoClass ) ) {
1766                         throw new MWException( "A {$this->repoClass} object is not set for this File.\n" );
1767                 }
1768         }
1769
1770         /**
1771          * Assert that $this->title is set to a Title
1772          * @throws MWException
1773          */
1774         protected function assertTitleDefined() {
1775                 if ( !( $this->title instanceof Title ) ) {
1776                         throw new MWException( "A Title object is not set for this File.\n" );
1777                 }
1778         }
1779 }