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          * Validate a thumbnail parameter at parse time.
  41          * Return true to accept the parameter, and false to reject it.
  42          * If you return false, the parser will do something quiet and forgiving.
  43          */
  44         abstract function validateParam( $name, $value );
  45
  46         /**
  47          * Merge a parameter array into a string appropriate for inclusion in filenames
  48          */
  49         abstract function makeParamString( $params );
  50
  51         /**
  52          * Parse a param string made with makeParamString back into an array
  53          */
  54         abstract function parseParamString( $str );
  55
  56         /**
  57          * Changes the parameter array as necessary, ready for transformation.
  58          * Should be idempotent.
  59          * Returns false if the parameters are unacceptable and the transform should fail
  60          */
  61         abstract function normaliseParams( $image, &$params );
  62
  63         /**
  64          * Get an image size array like that returned by getimagesize(), or false if it
  65          * can't be determined.
  66          *
  67          * @param Image $image The image object, or false if there isn't one
  68          * @param string $fileName The filename
  69          * @return array
  70          */
  71         abstract function getImageSize( $image, $path );
  72
  73         /**
  74          * Get handler-specific metadata which will be saved in the img_metadata field.
  75          *
  76          * @param Image $image The image object, or false if there isn't one
  77          * @param string $fileName The filename
  78          * @return string
  79          */
  80         function getMetadata( $image, $path ) { return ''; }
  81
  82         /**
  83          * Get a string describing the type of metadata, for display purposes.
  84          */
  85         function getMetadataType( $image ) { return false; }
  86
  87         /**
  88          * Check if the metadata string is valid for this handler.
  89          * If it returns false, Image will reload the metadata from the file and update the database
  90          */
  91         function isMetadataValid( $image, $metadata ) { return true; }
  92
  93         /**
  94          * Get a MediaTransformOutput object representing the transformed output. Does not
  95          * actually do the transform.
  96          *
  97          * @param Image $image The image object
  98          * @param string $dstPath Filesystem destination path
  99          * @param string $dstUrl Destination URL to use in output HTML
 100          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 101          */
 102         function getTransform( $image, $dstPath, $dstUrl, $params ) {
 103                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 104         }
 105
 106         /**
 107          * Get a MediaTransformOutput object representing the transformed output. Does the
 108          * transform unless $flags contains self::TRANSFORM_LATER.
 109          *
 110          * @param Image $image The image object
 111          * @param string $dstPath Filesystem destination path
 112          * @param string $dstUrl Destination URL to use in output HTML
 113          * @param array $params Arbitrary set of parameters validated by $this->validateParam()
 114          * @param integer $flags A bitfield, may contain self::TRANSFORM_LATER
 115          */
 116         abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );
 117
 118         /**
 119          * Get the thumbnail extension and MIME type for a given source MIME type
 120          * @return array thumbnail extension and MIME type
 121          */
 122         function getThumbType( $ext, $mime ) {
 123                 return array( $ext, $mime );
 124         }
 125
 126         /**
 127          * True if the handled types can be transformed
 128          */
 129         function canRender() { return true; }
 130         /**
 131          * True if handled types cannot be displayed directly in a browser
 132          * but can be rendered
 133          */
 134         function mustRender() { return false; }
 135         /**
 136          * True if the type has multi-page capabilities
 137          */
 138         function isMultiPage() { return false; }
 139         /**
 140          * Page count for a multi-page document, false if unsupported or unknown
 141          */
 142         function pageCount() { return false; }
 143         /**
 144          * False if the handler is disabled for all files
 145          */
 146         function isEnabled() { return true; }
 147
 148         /**
 149          * Get an associative array of page dimensions
 150          * Currently "width" and "height" are understood, but this might be
 151          * expanded in the future.
 152          * Returns false if unknown or if the document is not multi-page.
 153          */
 154         function getPageDimensions( $image, $page ) {
 155                 $gis = $this->getImageSize( $image, $image->getImagePath() );
 156                 return array(
 157                         'width' => $gis[0],
 158                         'height' => $gis[1]
 159                 );
 160         }
 161 }
 162
 163 /**
 164  * Media handler abstract base class for images
 165  *
 166  * @addtogroup Media
 167  */
 168 abstract class ImageHandler extends MediaHandler {
 169         function validateParam( $name, $value ) {
 170                 if ( in_array( $name, array( 'width', 'height' ) ) ) {
 171                         if ( $value <= 0 ) {
 172                                 return false;
 173                         } else {
 174                                 return true;
 175                         }
 176                 } else {
 177                         return false;
 178                 }
 179         }
 180
 181         function makeParamString( $params ) {
 182                 if ( isset( $params['physicalWidth'] ) ) {
 183                         $width = $params['physicalWidth'];
 184                 } else if ( isset( $params['width'] ) ) {
 185                         $width = $params['width'];
 186                 } else {
 187                         $width = 180;
 188                 }
 189                 # Removed for ProofreadPage
 190                 #$width = intval( $width );
 191                 return "{$width}px";
 192         }
 193
 194         function parseParamString( $str ) {
 195                 $m = false;
 196                 if ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
 197                         return array( 'width' => $m[1] );
 198                 } else {
 199                         return false;
 200                 }
 201         }
 202
 203         function getScriptParams( $params ) {
 204                 return array( 'width' => $params['width'] );
 205         }
 206
 207         function normaliseParams( $image, &$params ) {
 208                 $mimeType = $image->getMimeType();
 209
 210                 if ( !isset( $params['width'] ) ) {
 211                         return false;
 212                 }
 213                 if ( !isset( $params['page'] ) ) {
 214                         $params['page'] = 1;
 215                 }
 216                 $srcWidth = $image->getWidth( $params['page'] );
 217                 $srcHeight = $image->getHeight( $params['page'] );
 218                 if ( isset( $params['height'] ) && $params['height'] != -1 ) {
 219                         if ( $params['width'] * $srcHeight > $params['height'] * $srcWidth ) {
 220                                 $params['width'] = wfFitBoxWidth( $srcWidth, $srcHeight, $params['height'] );
 221                         }
 222                 }
 223                 $params['height'] = Image::scaleHeight( $srcWidth, $srcHeight, $params['width'] );
 224                 if ( !$this->validateThumbParams( $params['width'], $params['height'], $srcWidth, $srcHeight, $mimeType ) ) {
 225                         return false;
 226                 }
 227                 return true;
 228         }
 229
 230         /**
 231          * Get a transform output object without actually doing the transform
 232          */
 233         function getTransform( $image, $dstPath, $dstUrl, $params ) {
 234                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 235         }
 236
 237         /**
 238          * Validate thumbnail parameters and fill in the correct height
 239          *
 240          * @param integer &$width Specified width (input/output)
 241          * @param integer &$height Height (output only)
 242          * @return false to indicate that an error should be returned to the user.
 243          */
 244         function validateThumbParams( &$width, &$height, $srcWidth, $srcHeight, $mimeType ) {
 245                 $width = intval( $width );
 246
 247                 # Sanity check $width
 248                 if( $width <= 0) {
 249                         wfDebug( __METHOD__.": Invalid destination width: $width\n" );
 250                         return false;
 251                 }
 252                 if ( $srcWidth <= 0 ) {
 253                         wfDebug( __METHOD__.": Invalid source width: $srcWidth\n" );
 254                         return false;
 255                 }
 256
 257                 $height = Image::scaleHeight( $srcWidth, $srcHeight, $width );
 258                 return true;
 259         }
 260
 261         function getScriptedTransform( $image, $script, $params ) {
 262                 if ( !$this->normaliseParams( $image, $params ) ) {
 263                         return false;
 264                 }
 265                 $url = $script . '&' . wfArrayToCGI( $this->getScriptParams( $params ) );
 266                 return new ThumbnailImage( $url, $params['width'], $params['height'] );
 267         }
 268
 269         /**
 270          * Check for zero-sized thumbnails. These can be generated when
 271          * no disk space is available or some other error occurs
 272          *
 273          * @param $dstPath The location of the suspect file
 274          * @param $retval Return value of some shell process, file will be deleted if this is non-zero
 275          * @return true if removed, false otherwise
 276          */
 277         function removeBadFile( $dstPath, $retval = 0 ) {
 278                 $removed = false;
 279                 if( file_exists( $dstPath ) ) {
 280                         $thumbstat = stat( $dstPath );
 281                         if( $thumbstat['size'] == 0 || $retval != 0 ) {
 282                                 wfDebugLog( 'thumbnail',
 283                                         sprintf( 'Removing bad %d-byte thumbnail "%s"',
 284                                                 $thumbstat['size'], $dstPath ) );
 285                                 unlink( $dstPath );
 286                                 return true;
 287                         }
 288                 }
 289                 return false;
 290         }
 291
 292         function getImageSize( $image, $path ) {
 293                 wfSuppressWarnings();
 294                 $gis = getimagesize( $path );
 295                 wfRestoreWarnings();
 296                 return $gis;
 297         }
 298 }
 299
 300 ?>