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                         // unserialize to keep return parameter consistent.
 161                         Wikimedia\suppressWarnings();
 162                         $ret = unserialize( $metadata );
 163                         Wikimedia\restoreWarnings();
 164
 165                         return $ret;
 166                 }
 167
 168                 return $metadata;
 169         }
 170
 171         /**
 172          * Get a string describing the type of metadata, for display purposes.
 173          *
 174          * @note This method is currently unused.
 175          * @param File $image
 176          * @return string
 177          */
 178         function getMetadataType( $image ) {
 179                 return false;
 180         }
 181
 182         /**
 183          * Check if the metadata string is valid for this handler.
 184          * If it returns MediaHandler::METADATA_BAD (or false), Image
 185          * will reload the metadata from the file and update the database.
 186          * MediaHandler::METADATA_GOOD for if the metadata is a-ok,
 187          * MediaHandler::METADATA_COMPATIBLE if metadata is old but backwards
 188          * compatible (which may or may not trigger a metadata reload).
 189          *
 190          * @note Returning self::METADATA_BAD will trigger a metadata reload from
 191          *  file on page view. Always returning this from a broken file, or suddenly
 192          *  triggering as bad metadata for a large number of files can cause
 193          *  performance problems.
 194          * @param File $image
 195          * @param string $metadata The metadata in serialized form
 196          * @return bool
 197          */
 198         function isMetadataValid( $image, $metadata ) {
 199                 return self::METADATA_GOOD;
 200         }
 201
 202         /**
 203          * Get an array of standard (FormatMetadata type) metadata values.
 204          *
 205          * The returned data is largely the same as that from getMetadata(),
 206          * but formatted in a standard, stable, handler-independent way.
 207          * The idea being that some values like ImageDescription or Artist
 208          * are universal and should be retrievable in a handler generic way.
 209          *
 210          * The specific properties are the type of properties that can be
 211          * handled by the FormatMetadata class. These values are exposed to the
 212          * user via the filemetadata parser function.
 213          *
 214          * Details of the response format of this function can be found at
 215          * https://www.mediawiki.org/wiki/Manual:File_metadata_handling
 216          * tl/dr: the response is an associative array of
 217          * properties keyed by name, but the value can be complex. You probably
 218          * want to call one of the FormatMetadata::flatten* functions on the
 219          * property values before using them, or call
 220          * FormatMetadata::getFormattedData() on the full response array, which
 221          * transforms all values into prettified, human-readable text.
 222          *
 223          * Subclasses overriding this function must return a value which is a
 224          * valid API response fragment (all associative array keys are valid
 225          * XML tagnames).
 226          *
 227          * Note, if the file simply has no metadata, but the handler supports
 228          * this interface, it should return an empty array, not false.
 229          *
 230          * @param File $file
 231          * @return array|bool False if interface not supported
 232          * @since 1.23
 233          */
 234         public function getCommonMetaArray( File $file ) {
 235                 return false;
 236         }
 237
 238         /**
 239          * Get a MediaTransformOutput object representing an alternate of the transformed
 240          * output which will call an intermediary thumbnail assist script.
 241          *
 242          * Used when the repository has a thumbnailScriptUrl option configured.
 243          *
 244          * Return false to fall back to the regular getTransform().
 245          * @param File $image
 246          * @param string $script
 247          * @param array $params
 248          * @return bool|ThumbnailImage
 249          */
 250         function getScriptedTransform( $image, $script, $params ) {
 251                 return false;
 252         }
 253
 254         /**
 255          * Get a MediaTransformOutput object representing the transformed output. Does not
 256          * actually do the transform.
 257          *
 258          * @param File $image
 259          * @param string $dstPath Filesystem destination path
 260          * @param string $dstUrl Destination URL to use in output HTML
 261          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 262          * @return MediaTransformOutput
 263          */
 264         final function getTransform( $image, $dstPath, $dstUrl, $params ) {
 265                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 266         }
 267
 268         /**
 269          * Get a MediaTransformOutput object representing the transformed output. Does the
 270          * transform unless $flags contains self::TRANSFORM_LATER.
 271          *
 272          * @param File $image
 273          * @param string $dstPath Filesystem destination path
 274          * @param string $dstUrl Destination URL to use in output HTML
 275          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 276          *   Note: These parameters have *not* gone through $this->normaliseParams()
 277          * @param int $flags A bitfield, may contain self::TRANSFORM_LATER
 278          * @return MediaTransformOutput
 279          */
 280         abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );
 281
 282         /**
 283          * Get the thumbnail extension and MIME type for a given source MIME type
 284          *
 285          * @param string $ext Extension of original file
 286          * @param string $mime MIME type of original file
 287          * @param array $params Handler specific rendering parameters
 288          * @return array Thumbnail extension and MIME type
 289          */
 290         function getThumbType( $ext, $mime, $params = null ) {
 291                 $magic = MediaWiki\MediaWikiServices::getInstance()->getMimeAnalyzer();
 292                 if ( !$ext || $magic->isMatchingExtension( $ext, $mime ) === false ) {
 293                         // The extension is not valid for this MIME type and we do
 294                         // recognize the MIME type
 295                         $extensions = $magic->getExtensionsForType( $mime );
 296                         if ( $extensions ) {
 297                                 return [ strtok( $extensions, ' ' ), $mime ];
 298                         }
 299                 }
 300
 301                 // The extension is correct (true) or the MIME type is unknown to
 302                 // MediaWiki (null)
 303                 return [ $ext, $mime ];
 304         }
 305
 306         /**
 307          * @deprecated since 1.30, use MediaHandler::getContentHeaders instead
 308          * @param array $metadata
 309          * @return array
 310          */
 311         public function getStreamHeaders( $metadata ) {
 312                 wfDeprecated( __METHOD__, '1.30' );
 313                 return $this->getContentHeaders( $metadata );
 314         }
 315
 316         /**
 317          * True if the handled types can be transformed
 318          *
 319          * @param File $file
 320          * @return bool
 321          */
 322         public function canRender( $file ) {
 323                 return true;
 324         }
 325
 326         /**
 327          * True if handled types cannot be displayed directly in a browser
 328          * but can be rendered
 329          *
 330          * @param File $file
 331          * @return bool
 332          */
 333         public function mustRender( $file ) {
 334                 return false;
 335         }
 336
 337         /**
 338          * True if the type has multi-page capabilities
 339          *
 340          * @param File $file
 341          * @return bool
 342          */
 343         public function isMultiPage( $file ) {
 344                 return false;
 345         }
 346
 347         /**
 348          * Page count for a multi-page document, false if unsupported or unknown
 349          *
 350          * @param File $file
 351          * @return bool
 352          */
 353         function pageCount( File $file ) {
 354                 return false;
 355         }
 356
 357         /**
 358          * The material is vectorized and thus scaling is lossless
 359          *
 360          * @param File $file
 361          * @return bool
 362          */
 363         function isVectorized( $file ) {
 364                 return false;
 365         }
 366
 367         /**
 368          * The material is an image, and is animated.
 369          * In particular, video material need not return true.
 370          * @note Before 1.20, this was a method of ImageHandler only
 371          *
 372          * @param File $file
 373          * @return bool
 374          */
 375         function isAnimatedImage( $file ) {
 376                 return false;
 377         }
 378
 379         /**
 380          * If the material is animated, we can animate the thumbnail
 381          * @since 1.20
 382          *
 383          * @param File $file
 384          * @return bool If material is not animated, handler may return any value.
 385          */
 386         function canAnimateThumbnail( $file ) {
 387                 return true;
 388         }
 389
 390         /**
 391          * False if the handler is disabled for all files
 392          * @return bool
 393          */
 394         function isEnabled() {
 395                 return true;
 396         }
 397
 398         /**
 399          * Get an associative array of page dimensions
 400          * Currently "width" and "height" are understood, but this might be
 401          * expanded in the future.
 402          * Returns false if unknown.
 403          *
 404          * It is expected that handlers for paged media (e.g. DjVuHandler)
 405          * will override this method so that it gives the correct results
 406          * for each specific page of the file, using the $page argument.
 407          *
 408          * @note For non-paged media, use getImageSize.
 409          *
 410          * @param File $image
 411          * @param int $page What page to get dimensions of
 412          * @return array|bool
 413          */
 414         function getPageDimensions( File $image, $page ) {
 415                 $gis = $this->getImageSize( $image, $image->getLocalRefPath() );
 416                 if ( $gis ) {
 417                         return [
 418                                 'width' => $gis[0],
 419                                 'height' => $gis[1]
 420                         ];
 421                 } else {
 422                         return false;
 423                 }
 424         }
 425
 426         /**
 427          * Generic getter for text layer.
 428          * Currently overloaded by PDF and DjVu handlers
 429          * @param File $image
 430          * @param int $page Page number to get information for
 431          * @return bool|string Page text or false when no text found or if
 432          *   unsupported.
 433          */
 434         function getPageText( File $image, $page ) {
 435                 return false;
 436         }
 437
 438         /**
 439          * Get the text of the entire document.
 440          * @param File $file
 441          * @return bool|string The text of the document or false if unsupported.
 442          */
 443         public function getEntireText( File $file ) {
 444                 $numPages = $file->pageCount();
 445                 if ( !$numPages ) {
 446                         // Not a multipage document
 447                         return $this->getPageText( $file, 1 );
 448                 }
 449                 $document = '';
 450                 for ( $i = 1; $i <= $numPages; $i++ ) {
 451                         $curPage = $this->getPageText( $file, $i );
 452                         if ( is_string( $curPage ) ) {
 453                                 $document .= $curPage . "\n";
 454                         }
 455                 }
 456                 if ( $document !== '' ) {
 457                         return $document;
 458                 }
 459                 return false;
 460         }
 461
 462         /**
 463          * Get an array structure that looks like this:
 464          *
 465          * [
 466          *    'visible' => [
 467          *       'Human-readable name' => 'Human readable value',
 468          *       ...
 469          *    ],
 470          *    'collapsed' => [
 471          *       'Human-readable name' => 'Human readable value',
 472          *       ...
 473          *    ]
 474          * ]
 475          * The UI will format this into a table where the visible fields are always
 476          * visible, and the collapsed fields are optionally visible.
 477          *
 478          * The function should return false if there is no metadata to display.
 479          */
 480
 481         /**
 482          * @todo FIXME: This interface is not very flexible. The media handler
 483          * should generate HTML instead. It can do all the formatting according
 484          * to some standard. That makes it possible to do things like visual
 485          * indication of grouped and chained streams in ogg container files.
 486          * @param File $image
 487          * @param bool|IContextSource $context Context to use (optional)
 488          * @return array|bool
 489          */
 490         function formatMetadata( $image, $context = false ) {
 491                 return false;
 492         }
 493
 494         /** sorts the visible/invisible field.
 495          * Split off from ImageHandler::formatMetadata, as used by more than
 496          * one type of handler.
 497          *
 498          * This is used by the media handlers that use the FormatMetadata class
 499          *
 500          * @param array $metadataArray
 501          * @param bool|IContextSource $context Context to use (optional)
 502          * @return array Array for use displaying metadata.
 503          */
 504         function formatMetadataHelper( $metadataArray, $context = false ) {
 505                 $result = [
 506                         'visible' => [],
 507                         'collapsed' => []
 508                 ];
 509
 510                 $formatted = FormatMetadata::getFormattedData( $metadataArray, $context );
 511                 // Sort fields into visible and collapsed
 512                 $visibleFields = $this->visibleMetadataFields();
 513                 foreach ( $formatted as $name => $value ) {
 514                         $tag = strtolower( $name );
 515                         self::addMeta( $result,
 516                                 in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
 517                                 'exif',
 518                                 $tag,
 519                                 $value
 520                         );
 521                 }
 522
 523                 return $result;
 524         }
 525
 526         /**
 527          * Get a list of metadata items which should be displayed when
 528          * the metadata table is collapsed.
 529          *
 530          * @return array Array of strings
 531          */
 532         protected function visibleMetadataFields() {
 533                 return FormatMetadata::getVisibleFields();
 534         }
 535
 536         /**
 537          * This is used to generate an array element for each metadata value
 538          * That array is then used to generate the table of metadata values
 539          * on the image page
 540          *
 541          * @param array &$array An array containing elements for each type of visibility
 542          *   and each of those elements being an array of metadata items. This function adds
 543          *   a value to that array.
 544          * @param string $visibility ('visible' or 'collapsed') if this value is hidden
 545          *   by default.
 546          * @param string $type Type of metadata tag (currently always 'exif')
 547          * @param string $id The name of the metadata tag (like 'artist' for example).
 548          *   its name in the table displayed is the message "$type-$id" (Ex exif-artist ).
 549          * @param string $value Thingy goes into a wikitext table; it used to be escaped but
 550          *   that was incompatible with previous practise of customized display
 551          *   with wikitext formatting via messages such as 'exif-model-value'.
 552          *   So the escaping is taken back out, but generally this seems a confusing
 553          *   interface.
 554          * @param bool|string $param Value to pass to the message for the name of the field
 555          *   as $1. Currently this parameter doesn't seem to ever be used.
 556          *
 557          * Note, everything here is passed through the parser later on (!)
 558          */
 559         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 560                 $msg = wfMessage( "$type-$id", $param );
 561                 if ( $msg->exists() ) {
 562                         $name = $msg->text();
 563                 } else {
 564                         // This is for future compatibility when using instant commons.
 565                         // So as to not display as ugly a name if a new metadata
 566                         // property is defined that we don't know about
 567                         // (not a major issue since such a property would be collapsed
 568                         // by default).
 569                         wfDebug( __METHOD__ . ' Unknown metadata name: ' . $id . "\n" );
 570                         $name = wfEscapeWikiText( $id );
 571                 }
 572                 $array[$visibility][] = [
 573                         'id' => "$type-$id",
 574                         'name' => $name,
 575                         'value' => $value
 576                 ];
 577         }
 578
 579         /**
 580          * Short description. Shown on Special:Search results.
 581          *
 582          * @param File $file
 583          * @return string
 584          */
 585         function getShortDesc( $file ) {
 586                 return self::getGeneralShortDesc( $file );
 587         }
 588
 589         /**
 590          * Long description. Shown under image on image description page surounded by ().
 591          *
 592          * @param File $file
 593          * @return string
 594          */
 595         function getLongDesc( $file ) {
 596                 return self::getGeneralLongDesc( $file );
 597         }
 598
 599         /**
 600          * Used instead of getShortDesc if there is no handler registered for file.
 601          *
 602          * @param File $file
 603          * @return string
 604          */
 605         static function getGeneralShortDesc( $file ) {
 606                 global $wgLang;
 607
 608                 return htmlspecialchars( $wgLang->formatSize( $file->getSize() ) );
 609         }
 610
 611         /**
 612          * Used instead of getLongDesc if there is no handler registered for file.
 613          *
 614          * @param File $file
 615          * @return string
 616          */
 617         static function getGeneralLongDesc( $file ) {
 618                 return wfMessage( 'file-info' )->sizeParams( $file->getSize() )
 619                         ->params( '<span class="mime-type">' . $file->getMimeType() . '</span>' )->parse();
 620         }
 621
 622         /**
 623          * Calculate the largest thumbnail width for a given original file size
 624          * such that the thumbnail's height is at most $maxHeight.
 625          * @param int $boxWidth Width of the thumbnail box.
 626          * @param int $boxHeight Height of the thumbnail box.
 627          * @param int $maxHeight Maximum height expected for the thumbnail.
 628          * @return int
 629          */
 630         public static function fitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 631                 $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 632                 $roundedUp = ceil( $idealWidth );
 633                 if ( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight ) {
 634                         return floor( $idealWidth );
 635                 } else {
 636                         return $roundedUp;
 637                 }
 638         }
 639
 640         /**
 641          * Shown in file history box on image description page.
 642          *
 643          * @param File $file
 644          * @return string Dimensions
 645          */
 646         function getDimensionsString( $file ) {
 647                 return '';
 648         }
 649
 650         /**
 651          * Modify the parser object post-transform.
 652          *
 653          * This is often used to do $parser->addOutputHook(),
 654          * in order to add some javascript to render a viewer.
 655          * See TimedMediaHandler or OggHandler for an example.
 656          *
 657          * @param Parser $parser
 658          * @param File $file
 659          */
 660         function parserTransformHook( $parser, $file ) {
 661         }
 662
 663         /**
 664          * File validation hook called on upload.
 665          *
 666          * If the file at the given local path is not valid, or its MIME type does not
 667          * match the handler class, a Status object should be returned containing
 668          * relevant errors.
 669          *
 670          * @param string $fileName The local path to the file.
 671          * @return Status
 672          */
 673         function verifyUpload( $fileName ) {
 674                 return Status::newGood();
 675         }
 676
 677         /**
 678          * Check for zero-sized thumbnails. These can be generated when
 679          * no disk space is available or some other error occurs
 680          *
 681          * @param string $dstPath The location of the suspect file
 682          * @param int $retval Return value of some shell process, file will be deleted if this is non-zero
 683          * @return bool True if removed, false otherwise
 684          */
 685         function removeBadFile( $dstPath, $retval = 0 ) {
 686                 if ( file_exists( $dstPath ) ) {
 687                         $thumbstat = stat( $dstPath );
 688                         if ( $thumbstat['size'] == 0 || $retval != 0 ) {
 689                                 $result = unlink( $dstPath );
 690
 691                                 if ( $result ) {
 692                                         wfDebugLog( 'thumbnail',
 693                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() succeeded',
 694                                                         $thumbstat['size'], $dstPath ) );
 695                                 } else {
 696                                         wfDebugLog( 'thumbnail',
 697                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() failed',
 698                                                         $thumbstat['size'], $dstPath ) );
 699                                 }
 700
 701                                 return true;
 702                         }
 703                 }
 704
 705                 return false;
 706         }
 707
 708         /**
 709          * Remove files from the purge list.
 710          *
 711          * This is used by some video handlers to prevent ?action=purge
 712          * from removing a transcoded video, which is expensive to
 713          * regenerate.
 714          *
 715          * @see LocalFile::purgeThumbnails
 716          *
 717          * @param array &$files
 718          * @param array $options Purge options. Currently will always be
 719          *  an array with a single key 'forThumbRefresh' set to true.
 720          */
 721         public function filterThumbnailPurgeList( &$files, $options ) {
 722                 // Do nothing
 723         }
 724
 725         /**
 726          * True if the handler can rotate the media
 727          * @since 1.24 non-static. From 1.21-1.23 was static
 728          * @return bool
 729          */
 730         public function canRotate() {
 731                 return false;
 732         }
 733
 734         /**
 735          * On supporting image formats, try to read out the low-level orientation
 736          * of the file and return the angle that the file needs to be rotated to
 737          * be viewed.
 738          *
 739          * This information is only useful when manipulating the original file;
 740          * the width and height we normally work with is logical, and will match
 741          * any produced output views.
 742          *
 743          * For files we don't know, we return 0.
 744          *
 745          * @param File $file
 746          * @return int 0, 90, 180 or 270
 747          */
 748         public function getRotation( $file ) {
 749                 return 0;
 750         }
 751
 752         /**
 753          * Log an error that occurred in an external process
 754          *
 755          * Moved from BitmapHandler to MediaHandler with MediaWiki 1.23
 756          *
 757          * @since 1.23
 758          * @param int $retval
 759          * @param string $err Error reported by command. Anything longer than
 760          * MediaHandler::MAX_ERR_LOG_SIZE is stripped off.
 761          * @param string $cmd
 762          */
 763         protected function logErrorForExternalProcess( $retval, $err, $cmd ) {
 764                 # Keep error output limited (T59985)
 765                 $errMessage = trim( substr( $err, 0, self::MAX_ERR_LOG_SIZE ) );
 766
 767                 wfDebugLog( 'thumbnail',
 768                         sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
 769                                         wfHostname(), $retval, $errMessage, $cmd ) );
 770         }
 771
 772         /**
 773          * Get list of languages file can be viewed in.
 774          *
 775          * @param File $file
 776          * @return string[] Array of language codes, or empty array if unsupported.
 777          * @since 1.23
 778          */
 779         public function getAvailableLanguages( File $file ) {
 780                 return [];
 781         }
 782
 783         /**
 784          * On file types that support renderings in multiple languages,
 785          * which language is used by default if unspecified.
 786          *
 787          * If getAvailableLanguages returns a non-empty array, this must return
 788          * a valid language code. Otherwise can return null if files of this
 789          * type do not support alternative language renderings.
 790          *
 791          * @param File $file
 792          * @return string|null Language code or null if multi-language not supported for filetype.
 793          * @since 1.23
 794          */
 795         public function getDefaultRenderLanguage( File $file ) {
 796                 return null;
 797         }
 798
 799         /**
 800          * If its an audio file, return the length of the file. Otherwise 0.
 801          *
 802          * File::getLength() existed for a long time, but was calling a method
 803          * that only existed in some subclasses of this class (The TMH ones).
 804          *
 805          * @param File $file
 806          * @return float Length in seconds
 807          * @since 1.23
 808          */
 809         public function getLength( $file ) {
 810                 return 0.0;
 811         }
 812
 813         /**
 814          * True if creating thumbnails from the file is large or otherwise resource-intensive.
 815          * @param File $file
 816          * @return bool
 817          */
 818         public function isExpensiveToThumbnail( $file ) {
 819                 return false;
 820         }
 821
 822         /**
 823          * Returns whether or not this handler supports the chained generation of thumbnails according
 824          * to buckets
 825          * @return bool
 826          * @since 1.24
 827          */
 828         public function supportsBucketing() {
 829                 return false;
 830         }
 831
 832         /**
 833          * Returns a normalised params array for which parameters have been cleaned up for bucketing
 834          * purposes
 835          * @param array $params
 836          * @return array
 837          */
 838         public function sanitizeParamsForBucketing( $params ) {
 839                 return $params;
 840         }
 841
 842         /**
 843          * Gets configuration for the file warning message. Return value of
 844          * the following structure:
 845          *   [
 846          *     // Required, module with messages loaded for the client
 847          *     'module' => 'example.filewarning.messages',
 848          *     // Required, array of names of messages
 849          *     'messages' => [
 850          *       // Required, main warning message
 851          *       'main' => 'example-filewarning-main',
 852          *       // Optional, header for warning dialog
 853          *       'header' => 'example-filewarning-header',
 854          *       // Optional, footer for warning dialog
 855          *       'footer' => 'example-filewarning-footer',
 856          *       // Optional, text for more-information link (see below)
 857          *       'info' => 'example-filewarning-info',
 858          *     ],
 859          *     // Optional, link for more information
 860          *     'link' => 'http://example.com',
 861          *   ]
 862          *
 863          * Returns null if no warning is necessary.
 864          * @param File $file
 865          * @return array|null
 866          */
 867         public function getWarningConfig( $file ) {
 868                 return null;
 869         }
 870
 871         /**
 872          * Converts a dimensions array about a potentially multipage document from an
 873          * exhaustive list of ordered page numbers to a list of page ranges
 874          * @param Array $pagesByDimensions
 875          * @return String
 876          * @since 1.30
 877          */
 878         public static function getPageRangesByDimensions( $pagesByDimensions ) {
 879                 $pageRangesByDimensions = [];
 880
 881                 foreach ( $pagesByDimensions as $dimensions => $pageList ) {
 882                         $ranges = [];
 883                         $firstPage = $pageList[0];
 884                         $lastPage = $firstPage - 1;
 885
 886                         foreach ( $pageList as $page ) {
 887                                 if ( $page > $lastPage + 1 ) {
 888                                         if ( $firstPage != $lastPage ) {
 889                                                 $ranges[] = "$firstPage-$lastPage";
 890                                         } else {
 891                                                 $ranges[] = "$firstPage";
 892                                         }
 893
 894                                         $firstPage = $page;
 895                                 }
 896
 897                                 $lastPage = $page;
 898                         }
 899
 900                         if ( $firstPage != $lastPage ) {
 901                                 $ranges[] = "$firstPage-$lastPage";
 902                         } else {
 903                                 $ranges[] = "$firstPage";
 904                         }
 905
 906                         $pageRangesByDimensions[ $dimensions ] = $ranges;
 907                 }
 908
 909                 $dimensionsString = [];
 910                 foreach ( $pageRangesByDimensions as $dimensions => $pageRanges ) {
 911                         $dimensionsString[] = "$dimensions:" . implode( ',', $pageRanges );
 912                 }
 913
 914                 return implode( '/', $dimensionsString );
 915         }
 916
 917         /**
 918          * Get useful response headers for GET/HEAD requests for a file with the given metadata
 919          * @param array $metadata Contains this handler's unserialized getMetadata() for a file
 920          * @return array
 921          * @since 1.30
 922          */
 923         public function getContentHeaders( $metadata ) {
 924                 return [ 'X-Content-Dimensions' => '' ]; // T175689
 925         }
 926 }