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->getPath() );
 156                 return array(
 157                         'width' => $gis[0],
 158                         'height' => $gis[1]
 159                 );
 160         }
 161
 162         /**
 163          * Get an array structure that looks like this:
 164          *
 165          * array(
 166          *    'visible' => array(
 167          *       'Human-readable name' => 'Human readable value',
 168          *       ...
 169          *    ),
 170          *    'collapsed' => array(
 171          *       'Human-readable name' => 'Human readable value',
 172          *       ...
 173          *    )
 174          * )
 175          * The UI will format this into a table where the visible fields are always
 176          * visible, and the collapsed fields are optionally visible.
 177          *
 178          * The function should return false if there is no metadata to display.
 179          */
 180         function formatMetadata( $image, $metadata ) {
 181                 return false;
 182         }
 183
 184         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 185                 $array[$visibility][] = array(
 186                         'id' => "$type-$id",
 187                         'name' => wfMsg( "$type-$id", $param ),
 188                         'value' => wfEscapeWikiText( $value )
 189                 );
 190         }
 191
 192 }
 193
 194 /**
 195  * Media handler abstract base class for images
 196  *
 197  * @addtogroup Media
 198  */
 199 abstract class ImageHandler extends MediaHandler {
 200         function validateParam( $name, $value ) {
 201                 if ( in_array( $name, array( 'width', 'height' ) ) ) {
 202                         if ( $value <= 0 ) {
 203                                 return false;
 204                         } else {
 205                                 return true;
 206                         }
 207                 } else {
 208                         return false;
 209                 }
 210         }
 211
 212         function makeParamString( $params ) {
 213                 if ( isset( $params['physicalWidth'] ) ) {
 214                         $width = $params['physicalWidth'];
 215                 } elseif ( isset( $params['width'] ) ) {
 216                         $width = $params['width'];
 217                 } else {
 218                         throw new MWException( 'No width specified to '.__METHOD__ );
 219                 }
 220                 # Removed for ProofreadPage
 221                 #$width = intval( $width );
 222                 return "{$width}px";
 223         }
 224
 225         function parseParamString( $str ) {
 226                 $m = false;
 227                 if ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
 228                         return array( 'width' => $m[1] );
 229                 } else {
 230                         return false;
 231                 }
 232         }
 233
 234         function getScriptParams( $params ) {
 235                 return array( 'width' => $params['width'] );
 236         }
 237
 238         function normaliseParams( $image, &$params ) {
 239                 $mimeType = $image->getMimeType();
 240
 241                 if ( !isset( $params['width'] ) ) {
 242                         return false;
 243                 }
 244                 if ( !isset( $params['page'] ) ) {
 245                         $params['page'] = 1;
 246                 }
 247                 $srcWidth = $image->getWidth( $params['page'] );
 248                 $srcHeight = $image->getHeight( $params['page'] );
 249                 if ( isset( $params['height'] ) && $params['height'] != -1 ) {
 250                         if ( $params['width'] * $srcHeight > $params['height'] * $srcWidth ) {
 251                                 $params['width'] = wfFitBoxWidth( $srcWidth, $srcHeight, $params['height'] );
 252                         }
 253                 }
 254                 $params['height'] = File::scaleHeight( $srcWidth, $srcHeight, $params['width'] );
 255                 if ( !$this->validateThumbParams( $params['width'], $params['height'], $srcWidth, $srcHeight, $mimeType ) ) {
 256                         return false;
 257                 }
 258                 return true;
 259         }
 260
 261         /**
 262          * Get a transform output object without actually doing the transform
 263          */
 264         function getTransform( $image, $dstPath, $dstUrl, $params ) {
 265                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 266         }
 267
 268         /**
 269          * Validate thumbnail parameters and fill in the correct height
 270          *
 271          * @param integer &$width Specified width (input/output)
 272          * @param integer &$height Height (output only)
 273          * @return false to indicate that an error should be returned to the user.
 274          */
 275         function validateThumbParams( &$width, &$height, $srcWidth, $srcHeight, $mimeType ) {
 276                 $width = intval( $width );
 277
 278                 # Sanity check $width
 279                 if( $width <= 0) {
 280                         wfDebug( __METHOD__.": Invalid destination width: $width\n" );
 281                         return false;
 282                 }
 283                 if ( $srcWidth <= 0 ) {
 284                         wfDebug( __METHOD__.": Invalid source width: $srcWidth\n" );
 285                         return false;
 286                 }
 287
 288                 $height = File::scaleHeight( $srcWidth, $srcHeight, $width );
 289                 return true;
 290         }
 291
 292         function getScriptedTransform( $image, $script, $params ) {
 293                 if ( !$this->normaliseParams( $image, $params ) ) {
 294                         return false;
 295                 }
 296                 $url = $script . '&' . wfArrayToCGI( $this->getScriptParams( $params ) );
 297                 return new ThumbnailImage( $url, $params['width'], $params['height'] );
 298         }
 299
 300         /**
 301          * Check for zero-sized thumbnails. These can be generated when
 302          * no disk space is available or some other error occurs
 303          *
 304          * @param $dstPath The location of the suspect file
 305          * @param $retval Return value of some shell process, file will be deleted if this is non-zero
 306          * @return true if removed, false otherwise
 307          */
 308         function removeBadFile( $dstPath, $retval = 0 ) {
 309                 if( file_exists( $dstPath ) ) {
 310                         $thumbstat = stat( $dstPath );
 311                         if( $thumbstat['size'] == 0 || $retval != 0 ) {
 312                                 wfDebugLog( 'thumbnail',
 313                                         sprintf( 'Removing bad %d-byte thumbnail "%s"',
 314                                                 $thumbstat['size'], $dstPath ) );
 315                                 unlink( $dstPath );
 316                                 return true;
 317                         }
 318                 }
 319                 return false;
 320         }
 321
 322         function getImageSize( $image, $path ) {
 323                 wfSuppressWarnings();
 324                 $gis = getimagesize( $path );
 325                 wfRestoreWarnings();
 326                 return $gis;
 327         }
 328 }
 329
 330