includes/media/Generic.php

   1 <?php
   2
   3 /**
   4  * Media-handling base classes and generic functionality
   5  */
   6
   7 /**
   8  * Base media handler class
   9  *
  10  * @addtogroup Media
  11  */
  12 abstract class MediaHandler {
  13         const TRANSFORM_LATER = 1;
  14
  15         /**
  16          * Instance cache
  17          */
  18         static $handlers = array();
  19
  20         /**
  21          * Get a MediaHandler for a given MIME type from the instance cache
  22          */
  23         static function getHandler( $type ) {
  24                 global $wgMediaHandlers;
  25                 if ( !isset( $wgMediaHandlers[$type] ) ) {
  26                         wfDebug( __METHOD__ . ": no handler found for $type.\n");
  27                         return false;
  28                 }
  29                 $class = $wgMediaHandlers[$type];
  30                 if ( !isset( self::$handlers[$class] ) ) {
  31                         self::$handlers[$class] = new $class;
  32                         if ( !self::$handlers[$class]->isEnabled() ) {
  33                                 self::$handlers[$class] = false;
  34                         }
  35                 }
  36                 return self::$handlers[$class];
  37         }
  38
  39         /**
  40          * Get an associative array mapping magic word IDs to parameter names.
  41          * Will be used by the parser to identify parameters.
  42          */
  43         abstract function getParamMap();
  44
  45         /*
  46          * Validate a thumbnail parameter at parse time.
  47          * Return true to accept the parameter, and false to reject it.
  48          * If you return false, the parser will do something quiet and forgiving.
  49          */
  50         abstract function validateParam( $name, $value );
  51
  52         /**
  53          * Merge a parameter array into a string appropriate for inclusion in filenames
  54          */
  55         abstract function makeParamString( $params );
  56
  57         /**
  58          * Parse a param string made with makeParamString back into an array
  59          */
  60         abstract function parseParamString( $str );
  61
  62         /**
  63          * Changes the parameter array as necessary, ready for transformation.
  64          * Should be idempotent.
  65          * Returns false if the parameters are unacceptable and the transform should fail
  66          */
  67         abstract function normaliseParams( $image, &$params );
  68
  69         /**
  70          * Get an image size array like that returned by getimagesize(), or false if it
  71          * can't be determined.
  72          *
  73          * @param Image $image The image object, or false if there isn't one
  74          * @param string $fileName The filename
  75          * @return array
  76          */
  77         abstract function getImageSize( $image, $path );
  78
  79         /**
  80          * Get handler-specific metadata which will be saved in the img_metadata field.
  81          *
  82          * @param Image $image The image object, or false if there isn't one
  83          * @param string $fileName The filename
  84          * @return string
  85          */
  86         function getMetadata( $image, $path ) { return ''; }
  87
  88         /**
  89          * Get a string describing the type of metadata, for display purposes.
  90          */
  91         function getMetadataType( $image ) { return false; }
  92
  93         /**
  94          * Check if the metadata string is valid for this handler.
  95          * If it returns false, Image will reload the metadata from the file and update the database
  96          */
  97         function isMetadataValid( $image, $metadata ) { return true; }
  98
  99         /**
 100          * Get a MediaTransformOutput object representing the transformed output. Does not
 101          * actually do the transform.
 102          *
 103          * @param Image $image The image object
 104          * @param string $dstPath Filesystem destination path
 105          * @param string $dstUrl Destination URL to use in output HTML
 106          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 107          */
 108         function getTransform( $image, $dstPath, $dstUrl, $params ) {
 109                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 110         }
 111
 112         /**
 113          * Get a MediaTransformOutput object representing the transformed output. Does the
 114          * transform unless $flags contains self::TRANSFORM_LATER.
 115          *
 116          * @param Image $image The image object
 117          * @param string $dstPath Filesystem destination path
 118          * @param string $dstUrl Destination URL to use in output HTML
 119          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 120          * @param integer $flags A bitfield, may contain self::TRANSFORM_LATER
 121          */
 122         abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );
 123
 124         /**
 125          * Get the thumbnail extension and MIME type for a given source MIME type
 126          * @return array thumbnail extension and MIME type
 127          */
 128         function getThumbType( $ext, $mime ) {
 129                 return array( $ext, $mime );
 130         }
 131
 132         /**
 133          * True if the handled types can be transformed
 134          */
 135         function canRender( $file ) { return true; }
 136         /**
 137          * True if handled types cannot be displayed directly in a browser
 138          * but can be rendered
 139          */
 140         function mustRender( $file ) { return false; }
 141         /**
 142          * True if the type has multi-page capabilities
 143          */
 144         function isMultiPage( $file ) { return false; }
 145         /**
 146          * Page count for a multi-page document, false if unsupported or unknown
 147          */
 148         function pageCount( $file ) { return false; }
 149         /**
 150          * False if the handler is disabled for all files
 151          */
 152         function isEnabled() { return true; }
 153
 154         /**
 155          * Get an associative array of page dimensions
 156          * Currently "width" and "height" are understood, but this might be
 157          * expanded in the future.
 158          * Returns false if unknown or if the document is not multi-page.
 159          */
 160         function getPageDimensions( $image, $page ) {
 161                 $gis = $this->getImageSize( $image, $image->getPath() );
 162                 return array(
 163                         'width' => $gis[0],
 164                         'height' => $gis[1]
 165                 );
 166         }
 167
 168         /**
 169          * Get an array structure that looks like this:
 170          *
 171          * array(
 172          *    'visible' => array(
 173          *       'Human-readable name' => 'Human readable value',
 174          *       ...
 175          *    ),
 176          *    'collapsed' => array(
 177          *       'Human-readable name' => 'Human readable value',
 178          *       ...
 179          *    )
 180          * )
 181          * The UI will format this into a table where the visible fields are always
 182          * visible, and the collapsed fields are optionally visible.
 183          *
 184          * The function should return false if there is no metadata to display.
 185          */
 186
 187         /**
 188          * FIXME: I don't really like this interface, it's not very flexible
 189          * I think the media handler should generate HTML instead. It can do
 190          * all the formatting according to some standard. That makes it possible
 191          * to do things like visual indication of grouped and chained streams
 192          * in ogg container files.
 193          */
 194         function formatMetadata( $image, $metadata ) {
 195                 return false;
 196         }
 197
 198         /**
 199          * @fixme document this!
 200          * 'value' thingy goes into a wikitext table; it used to be escaped but
 201          * that was incompatible with previous practice of customized display
 202          * with wikitext formatting via messages such as 'exif-model-value'.
 203          * So the escaping is taken back out, but generally this seems a confusing
 204          * interface.
 205          */
 206         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 207                 $array[$visibility][] = array(
 208                         'id' => "$type-$id",
 209                         'name' => wfMsg( "$type-$id", $param ),
 210                         'value' => $value
 211                 );
 212         }
 213
 214         function getShortDesc( $file ) {
 215                 global $wgLang;
 216                 $nbytes = '(' . wfMsgExt( 'nbytes', array( 'parsemag', 'escape' ),
 217                         $wgLang->formatNum( $file->getSize() ) ) . ')';
 218                 return "$nbytes";
 219         }
 220
 221         function getLongDesc( $file ) {
 222                 global $wgUser;
 223                 $sk = $wgUser->getSkin();
 224                 return wfMsg( 'file-info', $sk->formatSize( $file->getSize() ), $file->getMimeType() );
 225         }
 226
 227         function getDimensionsString() {
 228                 return '';
 229         }
 230
 231         /**
 232          * Modify the parser object post-transform
 233          */
 234         function parserTransformHook( $parser, $file ) {}
 235 }
 236
 237 /**
 238  * Media handler abstract base class for images
 239  *
 240  * @addtogroup Media
 241  */
 242 abstract class ImageHandler extends MediaHandler {
 243         function canRender( $file ) {
 244                 if ( $file->getWidth() && $file->getHeight() ) {
 245                         return true;
 246                 } else {
 247                         return false;
 248                 }
 249         }
 250
 251         function getParamMap() {
 252                 return array( 'img_width' => 'width' );
 253         }
 254
 255         function validateParam( $name, $value ) {
 256                 if ( in_array( $name, array( 'width', 'height' ) ) ) {
 257                         if ( $value <= 0 ) {
 258                                 return false;
 259                         } else {
 260                                 return true;
 261                         }
 262                 } else {
 263                         return false;
 264                 }
 265         }
 266
 267         function makeParamString( $params ) {
 268                 if ( isset( $params['physicalWidth'] ) ) {
 269                         $width = $params['physicalWidth'];
 270                 } elseif ( isset( $params['width'] ) ) {
 271                         $width = $params['width'];
 272                 } else {
 273                         throw new MWException( 'No width specified to '.__METHOD__ );
 274                 }
 275                 # Removed for ProofreadPage
 276                 #$width = intval( $width );
 277                 return "{$width}px";
 278         }
 279
 280         function parseParamString( $str ) {
 281                 $m = false;
 282                 if ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
 283                         return array( 'width' => $m[1] );
 284                 } else {
 285                         return false;
 286                 }
 287         }
 288
 289         function getScriptParams( $params ) {
 290                 return array( 'width' => $params['width'] );
 291         }
 292
 293         function normaliseParams( $image, &$params ) {
 294                 $mimeType = $image->getMimeType();
 295
 296                 if ( !isset( $params['width'] ) ) {
 297                         return false;
 298                 }
 299                 if ( !isset( $params['page'] ) ) {
 300                         $params['page'] = 1;
 301                 }
 302                 $srcWidth = $image->getWidth( $params['page'] );
 303                 $srcHeight = $image->getHeight( $params['page'] );
 304                 if ( isset( $params['height'] ) && $params['height'] != -1 ) {
 305                         if ( $params['width'] * $srcHeight > $params['height'] * $srcWidth ) {
 306                                 $params['width'] = wfFitBoxWidth( $srcWidth, $srcHeight, $params['height'] );
 307                         }
 308                 }
 309                 $params['height'] = File::scaleHeight( $srcWidth, $srcHeight, $params['width'] );
 310                 if ( !$this->validateThumbParams( $params['width'], $params['height'], $srcWidth, $srcHeight, $mimeType ) ) {
 311                         return false;
 312                 }
 313                 return true;
 314         }
 315
 316         /**
 317          * Get a transform output object without actually doing the transform
 318          */
 319         function getTransform( $image, $dstPath, $dstUrl, $params ) {
 320                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 321         }
 322
 323         /**
 324          * Validate thumbnail parameters and fill in the correct height
 325          *
 326          * @param integer &$width Specified width (input/output)
 327          * @param integer &$height Height (output only)
 328          * @return false to indicate that an error should be returned to the user.
 329          */
 330         function validateThumbParams( &$width, &$height, $srcWidth, $srcHeight, $mimeType ) {
 331                 $width = intval( $width );
 332
 333                 # Sanity check $width
 334                 if( $width <= 0) {
 335                         wfDebug( __METHOD__.": Invalid destination width: $width\n" );
 336                         return false;
 337                 }
 338                 if ( $srcWidth <= 0 ) {
 339                         wfDebug( __METHOD__.": Invalid source width: $srcWidth\n" );
 340                         return false;
 341                 }
 342
 343                 $height = File::scaleHeight( $srcWidth, $srcHeight, $width );
 344                 return true;
 345         }
 346
 347         function getScriptedTransform( $image, $script, $params ) {
 348                 if ( !$this->normaliseParams( $image, $params ) ) {
 349                         return false;
 350                 }
 351                 $url = $script . '&' . wfArrayToCGI( $this->getScriptParams( $params ) );
 352                 return new ThumbnailImage( $url, $params['width'], $params['height'] );
 353         }
 354
 355         /**
 356          * Check for zero-sized thumbnails. These can be generated when
 357          * no disk space is available or some other error occurs
 358          *
 359          * @param $dstPath The location of the suspect file
 360          * @param $retval Return value of some shell process, file will be deleted if this is non-zero
 361          * @return true if removed, false otherwise
 362          */
 363         function removeBadFile( $dstPath, $retval = 0 ) {
 364                 if( file_exists( $dstPath ) ) {
 365                         $thumbstat = stat( $dstPath );
 366                         if( $thumbstat['size'] == 0 || $retval != 0 ) {
 367                                 wfDebugLog( 'thumbnail',
 368                                         sprintf( 'Removing bad %d-byte thumbnail "%s"',
 369                                                 $thumbstat['size'], $dstPath ) );
 370                                 unlink( $dstPath );
 371                                 return true;
 372                         }
 373                 }
 374                 return false;
 375         }
 376
 377         function getImageSize( $image, $path ) {
 378                 wfSuppressWarnings();
 379                 $gis = getimagesize( $path );
 380                 wfRestoreWarnings();
 381                 return $gis;
 382         }
 383
 384         function getShortDesc( $file ) {
 385                 global $wgLang;
 386                 $nbytes = '(' . wfMsgExt( 'nbytes', array( 'parsemag', 'escape' ),
 387                         $wgLang->formatNum( $file->getSize() ) ) . ')';
 388                 $widthheight = wfMsgHtml( 'widthheight', $file->getWidth(), $file->getHeight() );
 389
 390                 return "$widthheight ($nbytes)";
 391         }
 392
 393         function getLongDesc( $file ) {
 394                 global $wgLang;
 395                 return wfMsgHtml('file-info-size', $file->getWidth(), $file->getHeight(),
 396                         $wgLang->formatSize( $file->getSize() ), $file->getMimeType() );
 397         }
 398
 399         function getDimensionsString( $file ) {
 400                 $pages = $file->pageCount();
 401                 if ( $pages > 1 ) {
 402                         return wfMsg( 'widthheightpage', $file->getWidth(), $file->getHeight(), $pages );
 403                 } else {
 404                         return wfMsg( 'widthheight', $file->getWidth(), $file->getHeight() );
 405                 }
 406         }
 407 }
 408
 409
 410