includes/media/MediaHandler.php

   1 <?php
   2 /**
   3  * Media-handling base classes and generic functionality.
   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 Media
  22  */
  23 use MediaWiki\MediaWikiServices;
  24
  25 /**
  26  * Base media handler class
  27  *
  28  * @ingroup Media
  29  */
  30 abstract class MediaHandler {
  31         const TRANSFORM_LATER = 1;
  32         const METADATA_GOOD = true;
  33         const METADATA_BAD = false;
  34         const METADATA_COMPATIBLE = 2; // for old but backwards compatible.
  35         /**
  36          * Max length of error logged by logErrorForExternalProcess()
  37          */
  38         const MAX_ERR_LOG_SIZE = 65535;
  39
  40         /**
  41          * Get a MediaHandler for a given MIME type from the instance cache
  42          *
  43          * @param string $type
  44          * @return MediaHandler|bool
  45          */
  46         static function getHandler( $type ) {
  47                 return MediaWikiServices::getInstance()
  48                         ->getMediaHandlerFactory()->getHandler( $type );
  49         }
  50
  51         /**
  52          * Get an associative array mapping magic word IDs to parameter names.
  53          * Will be used by the parser to identify parameters.
  54          */
  55         abstract public function getParamMap();
  56
  57         /**
  58          * Validate a thumbnail parameter at parse time.
  59          * Return true to accept the parameter, and false to reject it.
  60          * If you return false, the parser will do something quiet and forgiving.
  61          *
  62          * @param string $name
  63          * @param mixed $value
  64          */
  65         abstract public function validateParam( $name, $value );
  66
  67         /**
  68          * Merge a parameter array into a string appropriate for inclusion in filenames
  69          *
  70          * @param array $params Array of parameters that have been through normaliseParams.
  71          * @return string
  72          */
  73         abstract public function makeParamString( $params );
  74
  75         /**
  76          * Parse a param string made with makeParamString back into an array
  77          *
  78          * @param string $str The parameter string without file name (e.g. 122px)
  79          * @return array|bool Array of parameters or false on failure.
  80          */
  81         abstract public function parseParamString( $str );
  82
  83         /**
  84          * Changes the parameter array as necessary, ready for transformation.
  85          * Should be idempotent.
  86          * Returns false if the parameters are unacceptable and the transform should fail
  87          * @param File $image
  88          * @param array $params
  89          */
  90         abstract function normaliseParams( $image, &$params );
  91
  92         /**
  93          * Get an image size array like that returned by getimagesize(), or false if it
  94          * can't be determined.
  95          *
  96          * This function is used for determining the width, height and bitdepth directly
  97          * from an image. The results are stored in the database in the img_width,
  98          * img_height, img_bits fields.
  99          *
 100          * @note If this is a multipage file, return the width and height of the
 101          *  first page.
 102          *
 103          * @param File|FSFile $image The image object, or false if there isn't one.
 104          *   Warning, FSFile::getPropsFromPath might pass an FSFile instead of File (!)
 105          * @param string $path The filename
 106          * @return array|bool Follow the format of PHP getimagesize() internal function.
 107          *   See https://secure.php.net/getimagesize. MediaWiki will only ever use the
 108          *   first two array keys (the width and height), and the 'bits' associative
 109          *   key. All other array keys are ignored. Returning a 'bits' key is optional
 110          *   as not all formats have a notion of "bitdepth". Returns false on failure.
 111          */
 112         abstract function getImageSize( $image, $path );
 113
 114         /**
 115          * Get handler-specific metadata which will be saved in the img_metadata field.
 116          *
 117          * @param File|FSFile $image The image object, or false if there isn't one.
 118          *   Warning, FSFile::getPropsFromPath might pass an FSFile instead of File (!)
 119          * @param string $path The filename
 120          * @return string A string of metadata in php serialized form (Run through serialize())
 121          */
 122         function getMetadata( $image, $path ) {
 123                 return '';
 124         }
 125
 126         /**
 127          * Get metadata version.
 128          *
 129          * This is not used for validating metadata, this is used for the api when returning
 130          * metadata, since api content formats should stay the same over time, and so things
 131          * using ForeignApiRepo can keep backwards compatibility
 132          *
 133          * All core media handlers share a common version number, and extensions can
 134          * use the GetMetadataVersion hook to append to the array (they should append a unique
 135          * string so not to get confusing). If there was a media handler named 'foo' with metadata
 136          * version 3 it might add to the end of the array the element 'foo=3'. if the core metadata
 137          * version is 2, the end version string would look like '2;foo=3'.
 138          *
 139          * @return string Version string
 140          */
 141         static function getMetadataVersion() {
 142                 $version = [ '2' ]; // core metadata version
 143                 Hooks::run( 'GetMetadataVersion', [ &$version ] );
 144
 145                 return implode( ';', $version );
 146         }
 147
 148         /**
 149          * Convert metadata version.
 150          *
 151          * By default just returns $metadata, but can be used to allow
 152          * media handlers to convert between metadata versions.
 153          *
 154          * @param string|array $metadata Metadata array (serialized if string)
 155          * @param int $version Target version
 156          * @return array Serialized metadata in specified version, or $metadata on fail.
 157          */
 158         function convertMetadataVersion( $metadata, $version = 1 ) {
 159                 if ( !is_array( $metadata ) ) {
 160
 161                         // unserialize to keep return parameter consistent.
 162                         MediaWiki\suppressWarnings();
 163                         $ret = unserialize( $metadata );
 164                         MediaWiki\restoreWarnings();
 165
 166                         return $ret;
 167                 }
 168
 169                 return $metadata;
 170         }
 171
 172         /**
 173          * Get a string describing the type of metadata, for display purposes.
 174          *
 175          * @note This method is currently unused.
 176          * @param File $image
 177          * @return string
 178          */
 179         function getMetadataType( $image ) {
 180                 return false;
 181         }
 182
 183         /**
 184          * Check if the metadata string is valid for this handler.
 185          * If it returns MediaHandler::METADATA_BAD (or false), Image
 186          * will reload the metadata from the file and update the database.
 187          * MediaHandler::METADATA_GOOD for if the metadata is a-ok,
 188          * MediaHandler::METADATA_COMPATIBLE if metadata is old but backwards
 189          * compatible (which may or may not trigger a metadata reload).
 190          *
 191          * @note Returning self::METADATA_BAD will trigger a metadata reload from
 192          *  file on page view. Always returning this from a broken file, or suddenly
 193          *  triggering as bad metadata for a large number of files can cause
 194          *  performance problems.
 195          * @param File $image
 196          * @param string $metadata The metadata in serialized form
 197          * @return bool
 198          */
 199         function isMetadataValid( $image, $metadata ) {
 200                 return self::METADATA_GOOD;
 201         }
 202
 203         /**
 204          * Get an array of standard (FormatMetadata type) metadata values.
 205          *
 206          * The returned data is largely the same as that from getMetadata(),
 207          * but formatted in a standard, stable, handler-independent way.
 208          * The idea being that some values like ImageDescription or Artist
 209          * are universal and should be retrievable in a handler generic way.
 210          *
 211          * The specific properties are the type of properties that can be
 212          * handled by the FormatMetadata class. These values are exposed to the
 213          * user via the filemetadata parser function.
 214          *
 215          * Details of the response format of this function can be found at
 216          * https://www.mediawiki.org/wiki/Manual:File_metadata_handling
 217          * tl/dr: the response is an associative array of
 218          * properties keyed by name, but the value can be complex. You probably
 219          * want to call one of the FormatMetadata::flatten* functions on the
 220          * property values before using them, or call
 221          * FormatMetadata::getFormattedData() on the full response array, which
 222          * transforms all values into prettified, human-readable text.
 223          *
 224          * Subclasses overriding this function must return a value which is a
 225          * valid API response fragment (all associative array keys are valid
 226          * XML tagnames).
 227          *
 228          * Note, if the file simply has no metadata, but the handler supports
 229          * this interface, it should return an empty array, not false.
 230          *
 231          * @param File $file
 232          * @return array|bool False if interface not supported
 233          * @since 1.23
 234          */
 235         public function getCommonMetaArray( File $file ) {
 236                 return false;
 237         }
 238
 239         /**
 240          * Get a MediaTransformOutput object representing an alternate of the transformed
 241          * output which will call an intermediary thumbnail assist script.
 242          *
 243          * Used when the repository has a thumbnailScriptUrl option configured.
 244          *
 245          * Return false to fall back to the regular getTransform().
 246          * @param File $image
 247          * @param string $script
 248          * @param array $params
 249          * @return bool|ThumbnailImage
 250          */
 251         function getScriptedTransform( $image, $script, $params ) {
 252                 return false;
 253         }
 254
 255         /**
 256          * Get a MediaTransformOutput object representing the transformed output. Does not
 257          * actually do the transform.
 258          *
 259          * @param File $image The image object
 260          * @param string $dstPath Filesystem destination path
 261          * @param string $dstUrl Destination URL to use in output HTML
 262          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 263          * @return MediaTransformOutput
 264          */
 265         final function getTransform( $image, $dstPath, $dstUrl, $params ) {
 266                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 267         }
 268
 269         /**
 270          * Get a MediaTransformOutput object representing the transformed output. Does the
 271          * transform unless $flags contains self::TRANSFORM_LATER.
 272          *
 273          * @param File $image The image object
 274          * @param string $dstPath Filesystem destination path
 275          * @param string $dstUrl Destination URL to use in output HTML
 276          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 277          *   Note: These parameters have *not* gone through $this->normaliseParams()
 278          * @param int $flags A bitfield, may contain self::TRANSFORM_LATER
 279          * @return MediaTransformOutput
 280          */
 281         abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );
 282
 283         /**
 284          * Get the thumbnail extension and MIME type for a given source MIME type
 285          *
 286          * @param string $ext Extension of original file
 287          * @param string $mime MIME type of original file
 288          * @param array $params Handler specific rendering parameters
 289          * @return array Thumbnail extension and MIME type
 290          */
 291         function getThumbType( $ext, $mime, $params = null ) {
 292                 $magic = MimeMagic::singleton();
 293                 if ( !$ext || $magic->isMatchingExtension( $ext, $mime ) === false ) {
 294                         // The extension is not valid for this MIME type and we do
 295                         // recognize the MIME type
 296                         $extensions = $magic->getExtensionsForType( $mime );
 297                         if ( $extensions ) {
 298                                 return [ strtok( $extensions, ' ' ), $mime ];
 299                         }
 300                 }
 301
 302                 // The extension is correct (true) or the MIME type is unknown to
 303                 // MediaWiki (null)
 304                 return [ $ext, $mime ];
 305         }
 306
 307         /**
 308          * Get useful response headers for GET/HEAD requests for a file with the given metadata
 309          *
 310          * @param mixed $metadata Result of the getMetadata() function of this handler for a file
 311          * @return array
 312          */
 313         public function getStreamHeaders( $metadata ) {
 314                 return [];
 315         }
 316
 317         /**
 318          * True if the handled types can be transformed
 319          *
 320          * @param File $file
 321          * @return bool
 322          */
 323         public function canRender( $file ) {
 324                 return true;
 325         }
 326
 327         /**
 328          * True if handled types cannot be displayed directly in a browser
 329          * but can be rendered
 330          *
 331          * @param File $file
 332          * @return bool
 333          */
 334         public function mustRender( $file ) {
 335                 return false;
 336         }
 337
 338         /**
 339          * True if the type has multi-page capabilities
 340          *
 341          * @param File $file
 342          * @return bool
 343          */
 344         public function isMultiPage( $file ) {
 345                 return false;
 346         }
 347
 348         /**
 349          * Page count for a multi-page document, false if unsupported or unknown
 350          *
 351          * @param File $file
 352          * @return bool
 353          */
 354         function pageCount( File $file ) {
 355                 return false;
 356         }
 357
 358         /**
 359          * The material is vectorized and thus scaling is lossless
 360          *
 361          * @param File $file
 362          * @return bool
 363          */
 364         function isVectorized( $file ) {
 365                 return false;
 366         }
 367
 368         /**
 369          * The material is an image, and is animated.
 370          * In particular, video material need not return true.
 371          * @note Before 1.20, this was a method of ImageHandler only
 372          *
 373          * @param File $file
 374          * @return bool
 375          */
 376         function isAnimatedImage( $file ) {
 377                 return false;
 378         }
 379
 380         /**
 381          * If the material is animated, we can animate the thumbnail
 382          * @since 1.20
 383          *
 384          * @param File $file
 385          * @return bool If material is not animated, handler may return any value.
 386          */
 387         function canAnimateThumbnail( $file ) {
 388                 return true;
 389         }
 390
 391         /**
 392          * False if the handler is disabled for all files
 393          * @return bool
 394          */
 395         function isEnabled() {
 396                 return true;
 397         }
 398
 399         /**
 400          * Get an associative array of page dimensions
 401          * Currently "width" and "height" are understood, but this might be
 402          * expanded in the future.
 403          * Returns false if unknown.
 404          *
 405          * It is expected that handlers for paged media (e.g. DjVuHandler)
 406          * will override this method so that it gives the correct results
 407          * for each specific page of the file, using the $page argument.
 408          *
 409          * @note For non-paged media, use getImageSize.
 410          *
 411          * @param File $image
 412          * @param int $page What page to get dimensions of
 413          * @return array|bool
 414          */
 415         function getPageDimensions( File $image, $page ) {
 416                 $gis = $this->getImageSize( $image, $image->getLocalRefPath() );
 417                 if ( $gis ) {
 418                         return [
 419                                 'width' => $gis[0],
 420                                 'height' => $gis[1]
 421                         ];
 422                 } else {
 423                         return false;
 424                 }
 425         }
 426
 427         /**
 428          * Generic getter for text layer.
 429          * Currently overloaded by PDF and DjVu handlers
 430          * @param File $image
 431          * @param int $page Page number to get information for
 432          * @return bool|string Page text or false when no text found or if
 433          *   unsupported.
 434          */
 435         function getPageText( File $image, $page ) {
 436                 return false;
 437         }
 438
 439         /**
 440          * Get the text of the entire document.
 441          * @param File $file
 442          * @return bool|string The text of the document or false if unsupported.
 443          */
 444         public function getEntireText( File $file ) {
 445                 $numPages = $file->pageCount();
 446                 if ( !$numPages ) {
 447                         // Not a multipage document
 448                         return $this->getPageText( $file, 1 );
 449                 }
 450                 $document = '';
 451                 for ( $i = 1; $i <= $numPages; $i++ ) {
 452                         $curPage = $this->getPageText( $file, $i );
 453                         if ( is_string( $curPage ) ) {
 454                                 $document .= $curPage . "\n";
 455                         }
 456                 }
 457                 if ( $document !== '' ) {
 458                         return $document;
 459                 }
 460                 return false;
 461         }
 462
 463         /**
 464          * Get an array structure that looks like this:
 465          *
 466          * [
 467          *    'visible' => [
 468          *       'Human-readable name' => 'Human readable value',
 469          *       ...
 470          *    ],
 471          *    'collapsed' => [
 472          *       'Human-readable name' => 'Human readable value',
 473          *       ...
 474          *    ]
 475          * ]
 476          * The UI will format this into a table where the visible fields are always
 477          * visible, and the collapsed fields are optionally visible.
 478          *
 479          * The function should return false if there is no metadata to display.
 480          */
 481
 482         /**
 483          * @todo FIXME: This interface is not very flexible. The media handler
 484          * should generate HTML instead. It can do all the formatting according
 485          * to some standard. That makes it possible to do things like visual
 486          * indication of grouped and chained streams in ogg container files.
 487          * @param File $image
 488          * @param bool|IContextSource $context Context to use (optional)
 489          * @return array|bool
 490          */
 491         function formatMetadata( $image, $context = false ) {
 492                 return false;
 493         }
 494
 495         /** sorts the visible/invisible field.
 496          * Split off from ImageHandler::formatMetadata, as used by more than
 497          * one type of handler.
 498          *
 499          * This is used by the media handlers that use the FormatMetadata class
 500          *
 501          * @param array $metadataArray Metadata array
 502          * @param bool|IContextSource $context Context to use (optional)
 503          * @return array Array for use displaying metadata.
 504          */
 505         function formatMetadataHelper( $metadataArray, $context = false ) {
 506                 $result = [
 507                         'visible' => [],
 508                         'collapsed' => []
 509                 ];
 510
 511                 $formatted = FormatMetadata::getFormattedData( $metadataArray, $context );
 512                 // Sort fields into visible and collapsed
 513                 $visibleFields = $this->visibleMetadataFields();
 514                 foreach ( $formatted as $name => $value ) {
 515                         $tag = strtolower( $name );
 516                         self::addMeta( $result,
 517                                 in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
 518                                 'exif',
 519                                 $tag,
 520                                 $value
 521                         );
 522                 }
 523
 524                 return $result;
 525         }
 526
 527         /**
 528          * Get a list of metadata items which should be displayed when
 529          * the metadata table is collapsed.
 530          *
 531          * @return array Array of strings
 532          */
 533         protected function visibleMetadataFields() {
 534                 return FormatMetadata::getVisibleFields();
 535         }
 536
 537         /**
 538          * This is used to generate an array element for each metadata value
 539          * That array is then used to generate the table of metadata values
 540          * on the image page
 541          *
 542          * @param array &$array An array containing elements for each type of visibility
 543          *   and each of those elements being an array of metadata items. This function adds
 544          *   a value to that array.
 545          * @param string $visibility ('visible' or 'collapsed') if this value is hidden
 546          *   by default.
 547          * @param string $type Type of metadata tag (currently always 'exif')
 548          * @param string $id The name of the metadata tag (like 'artist' for example).
 549          *   its name in the table displayed is the message "$type-$id" (Ex exif-artist ).
 550          * @param string $value Thingy goes into a wikitext table; it used to be escaped but
 551          *   that was incompatible with previous practise of customized display
 552          *   with wikitext formatting via messages such as 'exif-model-value'.
 553          *   So the escaping is taken back out, but generally this seems a confusing
 554          *   interface.
 555          * @param bool|string $param Value to pass to the message for the name of the field
 556          *   as $1. Currently this parameter doesn't seem to ever be used.
 557          *
 558          * Note, everything here is passed through the parser later on (!)
 559          */
 560         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 561                 $msg = wfMessage( "$type-$id", $param );
 562                 if ( $msg->exists() ) {
 563                         $name = $msg->text();
 564                 } else {
 565                         // This is for future compatibility when using instant commons.
 566                         // So as to not display as ugly a name if a new metadata
 567                         // property is defined that we don't know about
 568                         // (not a major issue since such a property would be collapsed
 569                         // by default).
 570                         wfDebug( __METHOD__ . ' Unknown metadata name: ' . $id . "\n" );
 571                         $name = wfEscapeWikiText( $id );
 572                 }
 573                 $array[$visibility][] = [
 574                         'id' => "$type-$id",
 575                         'name' => $name,
 576                         'value' => $value
 577                 ];
 578         }
 579
 580         /**
 581          * Short description. Shown on Special:Search results.
 582          *
 583          * @param File $file
 584          * @return string
 585          */
 586         function getShortDesc( $file ) {
 587                 return self::getGeneralShortDesc( $file );
 588         }
 589
 590         /**
 591          * Long description. Shown under image on image description page surounded by ().
 592          *
 593          * @param File $file
 594          * @return string
 595          */
 596         function getLongDesc( $file ) {
 597                 return self::getGeneralLongDesc( $file );
 598         }
 599
 600         /**
 601          * Used instead of getShortDesc if there is no handler registered for file.
 602          *
 603          * @param File $file
 604          * @return string
 605          */
 606         static function getGeneralShortDesc( $file ) {
 607                 global $wgLang;
 608
 609                 return htmlspecialchars( $wgLang->formatSize( $file->getSize() ) );
 610         }
 611
 612         /**
 613          * Used instead of getLongDesc if there is no handler registered for file.
 614          *
 615          * @param File $file
 616          * @return string
 617          */
 618         static function getGeneralLongDesc( $file ) {
 619                 return wfMessage( 'file-info' )->sizeParams( $file->getSize() )
 620                         ->params( '<span class="mime-type">' . $file->getMimeType() . '</span>' )->parse();
 621         }
 622
 623         /**
 624          * Calculate the largest thumbnail width for a given original file size
 625          * such that the thumbnail's height is at most $maxHeight.
 626          * @param int $boxWidth Width of the thumbnail box.
 627          * @param int $boxHeight Height of the thumbnail box.
 628          * @param int $maxHeight Maximum height expected for the thumbnail.
 629          * @return int
 630          */
 631         public static function fitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 632                 $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 633                 $roundedUp = ceil( $idealWidth );
 634                 if ( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight ) {
 635                         return floor( $idealWidth );
 636                 } else {
 637                         return $roundedUp;
 638                 }
 639         }
 640
 641         /**
 642          * Shown in file history box on image description page.
 643          *
 644          * @param File $file
 645          * @return string Dimensions
 646          */
 647         function getDimensionsString( $file ) {
 648                 return '';
 649         }
 650
 651         /**
 652          * Modify the parser object post-transform.
 653          *
 654          * This is often used to do $parser->addOutputHook(),
 655          * in order to add some javascript to render a viewer.
 656          * See TimedMediaHandler or OggHandler for an example.
 657          *
 658          * @param Parser $parser
 659          * @param File $file
 660          */
 661         function parserTransformHook( $parser, $file ) {
 662         }
 663
 664         /**
 665          * File validation hook called on upload.
 666          *
 667          * If the file at the given local path is not valid, or its MIME type does not
 668          * match the handler class, a Status object should be returned containing
 669          * relevant errors.
 670          *
 671          * @param string $fileName The local path to the file.
 672          * @return Status
 673          */
 674         function verifyUpload( $fileName ) {
 675                 return Status::newGood();
 676         }
 677
 678         /**
 679          * Check for zero-sized thumbnails. These can be generated when
 680          * no disk space is available or some other error occurs
 681          *
 682          * @param string $dstPath The location of the suspect file
 683          * @param int $retval Return value of some shell process, file will be deleted if this is non-zero
 684          * @return bool True if removed, false otherwise
 685          */
 686         function removeBadFile( $dstPath, $retval = 0 ) {
 687                 if ( file_exists( $dstPath ) ) {
 688                         $thumbstat = stat( $dstPath );
 689                         if ( $thumbstat['size'] == 0 || $retval != 0 ) {
 690                                 $result = unlink( $dstPath );
 691
 692                                 if ( $result ) {
 693                                         wfDebugLog( 'thumbnail',
 694                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() succeeded',
 695                                                         $thumbstat['size'], $dstPath ) );
 696                                 } else {
 697                                         wfDebugLog( 'thumbnail',
 698                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() failed',
 699                                                         $thumbstat['size'], $dstPath ) );
 700                                 }
 701
 702                                 return true;
 703                         }
 704                 }
 705
 706                 return false;
 707         }
 708
 709         /**
 710          * Remove files from the purge list.
 711          *
 712          * This is used by some video handlers to prevent ?action=purge
 713          * from removing a transcoded video, which is expensive to
 714          * regenerate.
 715          *
 716          * @see LocalFile::purgeThumbnails
 717          *
 718          * @param array $files
 719          * @param array $options Purge options. Currently will always be
 720          *  an array with a single key 'forThumbRefresh' set to true.
 721          */
 722         public function filterThumbnailPurgeList( &$files, $options ) {
 723                 // Do nothing
 724         }
 725
 726         /**
 727          * True if the handler can rotate the media
 728          * @since 1.24 non-static. From 1.21-1.23 was static
 729          * @return bool
 730          */
 731         public function canRotate() {
 732                 return false;
 733         }
 734
 735         /**
 736          * On supporting image formats, try to read out the low-level orientation
 737          * of the file and return the angle that the file needs to be rotated to
 738          * be viewed.
 739          *
 740          * This information is only useful when manipulating the original file;
 741          * the width and height we normally work with is logical, and will match
 742          * any produced output views.
 743          *
 744          * For files we don't know, we return 0.
 745          *
 746          * @param File $file
 747          * @return int 0, 90, 180 or 270
 748          */
 749         public function getRotation( $file ) {
 750                 return 0;
 751         }
 752
 753         /**
 754          * Log an error that occurred in an external process
 755          *
 756          * Moved from BitmapHandler to MediaHandler with MediaWiki 1.23
 757          *
 758          * @since 1.23
 759          * @param int $retval
 760          * @param string $err Error reported by command. Anything longer than
 761          * MediaHandler::MAX_ERR_LOG_SIZE is stripped off.
 762          * @param string $cmd
 763          */
 764         protected function logErrorForExternalProcess( $retval, $err, $cmd ) {
 765                 # Keep error output limited (bug 57985)
 766                 $errMessage = trim( substr( $err, 0, self::MAX_ERR_LOG_SIZE ) );
 767
 768                 wfDebugLog( 'thumbnail',
 769                         sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
 770                                         wfHostname(), $retval, $errMessage, $cmd ) );
 771         }
 772
 773         /**
 774          * Get list of languages file can be viewed in.
 775          *
 776          * @param File $file
 777          * @return string[] Array of language codes, or empty array if unsupported.
 778          * @since 1.23
 779          */
 780         public function getAvailableLanguages( File $file ) {
 781                 return [];
 782         }
 783
 784         /**
 785          * On file types that support renderings in multiple languages,
 786          * which language is used by default if unspecified.
 787          *
 788          * If getAvailableLanguages returns a non-empty array, this must return
 789          * a valid language code. Otherwise can return null if files of this
 790          * type do not support alternative language renderings.
 791          *
 792          * @param File $file
 793          * @return string|null Language code or null if multi-language not supported for filetype.
 794          * @since 1.23
 795          */
 796         public function getDefaultRenderLanguage( File $file ) {
 797                 return null;
 798         }
 799
 800         /**
 801          * If its an audio file, return the length of the file. Otherwise 0.
 802          *
 803          * File::getLength() existed for a long time, but was calling a method
 804          * that only existed in some subclasses of this class (The TMH ones).
 805          *
 806          * @param File $file
 807          * @return float Length in seconds
 808          * @since 1.23
 809          */
 810         public function getLength( $file ) {
 811                 return 0.0;
 812         }
 813
 814         /**
 815          * True if creating thumbnails from the file is large or otherwise resource-intensive.
 816          * @param File $file
 817          * @return bool
 818          */
 819         public function isExpensiveToThumbnail( $file ) {
 820                 return false;
 821         }
 822
 823         /**
 824          * Returns whether or not this handler supports the chained generation of thumbnails according
 825          * to buckets
 826          * @return bool
 827          * @since 1.24
 828          */
 829         public function supportsBucketing() {
 830                 return false;
 831         }
 832
 833         /**
 834          * Returns a normalised params array for which parameters have been cleaned up for bucketing
 835          * purposes
 836          * @param array $params
 837          * @return array
 838          */
 839         public function sanitizeParamsForBucketing( $params ) {
 840                 return $params;
 841         }
 842
 843         /**
 844          * Gets configuration for the file warning message. Return value of
 845          * the following structure:
 846          *   [
 847          *     // Required, module with messages loaded for the client
 848          *     'module' => 'example.filewarning.messages',
 849          *     // Required, array of names of messages
 850          *     'messages' => [
 851          *       // Required, main warning message
 852          *       'main' => 'example-filewarning-main',
 853          *       // Optional, header for warning dialog
 854          *       'header' => 'example-filewarning-header',
 855          *       // Optional, footer for warning dialog
 856          *       'footer' => 'example-filewarning-footer',
 857          *       // Optional, text for more-information link (see below)
 858          *       'info' => 'example-filewarning-info',
 859          *     ],
 860          *     // Optional, link for more information
 861          *     'link' => 'http://example.com',
 862          *   ]
 863          *
 864          * Returns null if no warning is necessary.
 865          * @param File $file
 866          * @return array|null
 867          */
 868         public function getWarningConfig( $file ) {
 869                 return null;
 870         }
 871 }