Finally removing the deprecated and unused functions User::isSysop, User::isBureaucra...

[mediawiki.git] / includes / Image.php

<?php
/**
 * @package MediaWiki
 */

/**
 * NOTE FOR WINDOWS USERS:
 * To enable EXIF functions, add the folloing lines to the
 * "Windows extensions" section of php.ini:
 *
 * extension=extensions/php_mbstring.dll
 * extension=extensions/php_exif.dll
 */

/**
 * Bump this number when serialized cache records may be incompatible.
 */
define( 'MW_IMAGE_VERSION', 1 );

/**
 * Class to represent an image
 *
 * Provides methods to retrieve paths (physical, logical, URL),
 * to generate thumbnails or for uploading.
 * @package MediaWiki
 */
class Image
{
        /**#@+
         * @private
         */
        var     $name,          # name of the image (constructor)
                $imagePath,     # Path of the image (loadFromXxx)
                $url,           # Image URL (accessor)
                $title,         # Title object for this image (constructor)
                $fileExists,    # does the image file exist on disk? (loadFromXxx)
                $fromSharedDirectory, # load this image from $wgSharedUploadDirectory (loadFromXxx)
                $historyLine,   # Number of line to return by nextHistoryLine() (constructor)
                $historyRes,    # result of the query for the image's history (nextHistoryLine)
                $width,         # \
                $height,        #  |
                $bits,          #   --- returned by getimagesize (loadFromXxx)
                $attr,          # /
                $type,          # MEDIATYPE_xxx (bitmap, drawing, audio...)
                $mime,          # MIME type, determined by MimeMagic::guessMimeType
                $size,          # Size in bytes (loadFromXxx)
                $metadata,      # Metadata
                $dataLoaded,    # Whether or not all this has been loaded from the database (loadFromXxx)
                $lastError;     # Error string associated with a thumbnail display error


        /**#@-*/

        /**
         * Create an Image object from an image name
         *
         * @param string $name name of the image, used to create a title object using Title::makeTitleSafe
         * @public
         */
        function newFromName( $name ) {
                $title = Title::makeTitleSafe( NS_IMAGE, $name );
                if ( is_object( $title ) ) {
                        return new Image( $title );
                } else {
                        return NULL;
                }
        }

        /**
         * Obsolete factory function, use constructor
         * @deprecated
         */
        function newFromTitle( $title ) {
                return new Image( $title );
        }

        function Image( $title ) {
                if( !is_object( $title ) ) {
                        throw new MWException( 'Image constructor given bogus title.' );
                }
                $this->title =& $title;
                $this->name = $title->getDBkey();
                $this->metadata = serialize ( array() ) ;

                $n = strrpos( $this->name, '.' );
                $this->extension = Image::normalizeExtension( $n ?
                        substr( $this->name, $n + 1 ) : '' );
                $this->historyLine = 0;

                $this->dataLoaded = false;
        }

        
        /**
         * Normalize a file extension to the common form, and ensure it's clean.
         * Extensions with non-alphanumeric characters will be discarded.
         *
         * @param $ext string (without the .)
         * @return string
         */
        static function normalizeExtension( $ext ) {
                $lower = strtolower( $ext );
                $squish = array(
                        'htm' => 'html',
                        'jpeg' => 'jpg',
                        'mpeg' => 'mpg',
                        'tiff' => 'tif' );
                if( isset( $squish[$lower] ) ) {
                        return $squish[$lower];
                } elseif( preg_match( '/^[0-9a-z]+$/', $lower ) ) {
                        return $lower;
                } else {
                        return '';
                }
        }
        
        /**
         * Get the memcached keys
         * Returns an array, first element is the local cache key, second is the shared cache key, if there is one
         */
        function getCacheKeys( ) {
                global $wgDBname, $wgUseSharedUploads, $wgSharedUploadDBname, $wgCacheSharedUploads;

                $hashedName = md5($this->name);
                $keys = array( "$wgDBname:Image:$hashedName" );
                if ( $wgUseSharedUploads && $wgSharedUploadDBname && $wgCacheSharedUploads ) {
                        $keys[] = "$wgSharedUploadDBname:Image:$hashedName";
                }
                return $keys;
        }

        /**
         * Try to load image metadata from memcached. Returns true on success.
         */
        function loadFromCache() {
                global $wgUseSharedUploads, $wgMemc;
                wfProfileIn( __METHOD__ );
                $this->dataLoaded = false;
                $keys = $this->getCacheKeys();
                $cachedValues = $wgMemc->get( $keys[0] );

                // Check if the key existed and belongs to this version of MediaWiki
                if (!empty($cachedValues) && is_array($cachedValues)
                  && isset($cachedValues['version']) && ( $cachedValues['version'] == MW_IMAGE_VERSION )
                  && isset( $cachedValues['mime'] ) && isset( $cachedValues['metadata'] ) )
                {
                        if ( $wgUseSharedUploads && $cachedValues['fromShared']) {
                                # if this is shared file, we need to check if image
                                # in shared repository has not changed
                                if ( isset( $keys[1] ) ) {
                                        $commonsCachedValues = $wgMemc->get( $keys[1] );
                                        if (!empty($commonsCachedValues) && is_array($commonsCachedValues)
                                          && isset($commonsCachedValues['version'])
                                          && ( $commonsCachedValues['version'] == MW_IMAGE_VERSION )
                                          && isset($commonsCachedValues['mime'])) {
                                                wfDebug( "Pulling image metadata from shared repository cache\n" );
                                                $this->name = $commonsCachedValues['name'];
                                                $this->imagePath = $commonsCachedValues['imagePath'];
                                                $this->fileExists = $commonsCachedValues['fileExists'];
                                                $this->width = $commonsCachedValues['width'];
                                                $this->height = $commonsCachedValues['height'];
                                                $this->bits = $commonsCachedValues['bits'];
                                                $this->type = $commonsCachedValues['type'];
                                                $this->mime = $commonsCachedValues['mime'];
                                                $this->metadata = $commonsCachedValues['metadata'];
                                                $this->size = $commonsCachedValues['size'];
                                                $this->fromSharedDirectory = true;
                                                $this->dataLoaded = true;
                                                $this->imagePath = $this->getFullPath(true);
                                        }
                                }
                        } else {
                                wfDebug( "Pulling image metadata from local cache\n" );
                                $this->name = $cachedValues['name'];
                                $this->imagePath = $cachedValues['imagePath'];
                                $this->fileExists = $cachedValues['fileExists'];
                                $this->width = $cachedValues['width'];
                                $this->height = $cachedValues['height'];
                                $this->bits = $cachedValues['bits'];
                                $this->type = $cachedValues['type'];
                                $this->mime = $cachedValues['mime'];
                                $this->metadata = $cachedValues['metadata'];
                                $this->size = $cachedValues['size'];
                                $this->fromSharedDirectory = false;
                                $this->dataLoaded = true;
                                $this->imagePath = $this->getFullPath();
                        }
                }
                if ( $this->dataLoaded ) {
                        wfIncrStats( 'image_cache_hit' );
                } else {
                        wfIncrStats( 'image_cache_miss' );
                }

                wfProfileOut( __METHOD__ );
                return $this->dataLoaded;
        }

        /**
         * Save the image metadata to memcached
         */
        function saveToCache() {
                global $wgMemc, $wgUseSharedUploads;
                $this->load();
                $keys = $this->getCacheKeys();
                // We can't cache negative metadata for non-existent files,
                // because if the file later appears in commons, the local
                // keys won't be purged.
                if ( $this->fileExists || !$wgUseSharedUploads ) {
                        $cachedValues = array(
                                'version'    => MW_IMAGE_VERSION,
                                'name'       => $this->name,
                                'imagePath'  => $this->imagePath,
                                'fileExists' => $this->fileExists,
                                'fromShared' => $this->fromSharedDirectory,
                                'width'      => $this->width,
                                'height'     => $this->height,
                                'bits'       => $this->bits,
                                'type'       => $this->type,
                                'mime'       => $this->mime,
                                'metadata'   => $this->metadata,
                                'size'       => $this->size );

                        $wgMemc->set( $keys[0], $cachedValues, 60 * 60 * 24 * 7 ); // A week
                } else {
                        // However we should clear them, so they aren't leftover
                        // if we've deleted the file.
                        $wgMemc->delete( $keys[0] );
                }
        }

        /**
         * Load metadata from the file itself
         */
        function loadFromFile() {
                global $wgUseSharedUploads, $wgSharedUploadDirectory, $wgContLang, $wgShowEXIF;
                wfProfileIn( __METHOD__ );
                $this->imagePath = $this->getFullPath();
                $this->fileExists = file_exists( $this->imagePath );
                $this->fromSharedDirectory = false;
                $gis = array();

                if (!$this->fileExists) wfDebug(__METHOD__.': '.$this->imagePath." not found locally!\n");

                # If the file is not found, and a shared upload directory is used, look for it there.
                if (!$this->fileExists && $wgUseSharedUploads && $wgSharedUploadDirectory) {
                        # In case we're on a wgCapitalLinks=false wiki, we
                        # capitalize the first letter of the filename before
                        # looking it up in the shared repository.
                        $sharedImage = Image::newFromName( $wgContLang->ucfirst($this->name) );
                        $this->fileExists = $sharedImage && file_exists( $sharedImage->getFullPath(true) );
                        if ( $this->fileExists ) {
                                $this->name = $sharedImage->name;
                                $this->imagePath = $this->getFullPath(true);
                                $this->fromSharedDirectory = true;
                        }
                }


                if ( $this->fileExists ) {
                        $magic=& wfGetMimeMagic();

                        $this->mime = $magic->guessMimeType($this->imagePath,true);
                        $this->type = $magic->getMediaType($this->imagePath,$this->mime);

                        # Get size in bytes
                        $this->size = filesize( $this->imagePath );

                        $magic=& wfGetMimeMagic();

                        # Height and width
                        wfSuppressWarnings();
                        if( $this->mime == 'image/svg' ) {
                                $gis = wfGetSVGsize( $this->imagePath );
                        } elseif( $this->mime == 'image/vnd.djvu' ) {
                                $deja = new DjVuImage( $this->imagePath );
                                $gis = $deja->getImageSize();
                        } elseif ( !$magic->isPHPImageType( $this->mime ) ) {
                                # Don't try to get the width and height of sound and video files, that's bad for performance
                                $gis = false;
                        } else {
                                $gis = getimagesize( $this->imagePath );
                        }
                        wfRestoreWarnings();

                        wfDebug(__METHOD__.': '.$this->imagePath." loaded, ".$this->size." bytes, ".$this->mime.".\n");
                }
                else {
                        $this->mime = NULL;
                        $this->type = MEDIATYPE_UNKNOWN;
                        wfDebug(__METHOD__.': '.$this->imagePath." NOT FOUND!\n");
                }

                if( $gis ) {
                        $this->width = $gis[0];
                        $this->height = $gis[1];
                } else {
                        $this->width = 0;
                        $this->height = 0;
                }

                #NOTE: $gis[2] contains a code for the image type. This is no longer used.

                #NOTE: we have to set this flag early to avoid load() to be called
                # be some of the functions below. This may lead to recursion or other bad things!
                # as ther's only one thread of execution, this should be safe anyway.
                $this->dataLoaded = true;


                $this->metadata = serialize( $this->retrieveExifData( $this->imagePath ) );

                if ( isset( $gis['bits'] ) )  $this->bits = $gis['bits'];
                else $this->bits = 0;

                wfProfileOut( __METHOD__ );
        }

        /**
         * Load image metadata from the DB
         */
        function loadFromDB() {
                global $wgUseSharedUploads, $wgSharedUploadDBname, $wgSharedUploadDBprefix, $wgContLang;
                wfProfileIn( __METHOD__ );

                $dbr =& wfGetDB( DB_SLAVE );

                $this->checkDBSchema($dbr);

                $row = $dbr->selectRow( 'image',
                        array( 'img_size', 'img_width', 'img_height', 'img_bits',
                               'img_media_type', 'img_major_mime', 'img_minor_mime', 'img_metadata' ),
                        array( 'img_name' => $this->name ), __METHOD__ );
                if ( $row ) {
                        $this->fromSharedDirectory = false;
                        $this->fileExists = true;
                        $this->loadFromRow( $row );
                        $this->imagePath = $this->getFullPath();
                        // Check for rows from a previous schema, quietly upgrade them
                        if ( is_null($this->type) ) {
                                $this->upgradeRow();
                        }
                } elseif ( $wgUseSharedUploads && $wgSharedUploadDBname ) {
                        # In case we're on a wgCapitalLinks=false wiki, we
                        # capitalize the first letter of the filename before
                        # looking it up in the shared repository.
                        $name = $wgContLang->ucfirst($this->name);
                        $dbc =& wfGetDB( DB_SLAVE, 'commons' );

                        $row = $dbc->selectRow( "`$wgSharedUploadDBname`.{$wgSharedUploadDBprefix}image",
                                array(
                                        'img_size', 'img_width', 'img_height', 'img_bits',
                                        'img_media_type', 'img_major_mime', 'img_minor_mime', 'img_metadata' ),
                                array( 'img_name' => $name ), __METHOD__ );
                        if ( $row ) {
                                $this->fromSharedDirectory = true;
                                $this->fileExists = true;
                                $this->imagePath = $this->getFullPath(true);
                                $this->name = $name;
                                $this->loadFromRow( $row );

                                // Check for rows from a previous schema, quietly upgrade them
                                if ( is_null($this->type) ) {
                                        $this->upgradeRow();
                                }
                        }
                }

                if ( !$row ) {
                        $this->size = 0;
                        $this->width = 0;
                        $this->height = 0;
                        $this->bits = 0;
                        $this->type = 0;
                        $this->fileExists = false;
                        $this->fromSharedDirectory = false;
                        $this->metadata = serialize ( array() ) ;
                        $this->mime = false;
                }

                # Unconditionally set loaded=true, we don't want the accessors constantly rechecking
                $this->dataLoaded = true;
                wfProfileOut( __METHOD__ );
        }

        /*
         * Load image metadata from a DB result row
         */
        function loadFromRow( &$row ) {
                $this->size = $row->img_size;
                $this->width = $row->img_width;
                $this->height = $row->img_height;
                $this->bits = $row->img_bits;
                $this->type = $row->img_media_type;

                $major= $row->img_major_mime;
                $minor= $row->img_minor_mime;

                if (!$major) $this->mime = "unknown/unknown";
                else {
                        if (!$minor) $minor= "unknown";
                        $this->mime = $major.'/'.$minor;
                }

                $this->metadata = $row->img_metadata;
                if ( $this->metadata == "" ) $this->metadata = serialize ( array() ) ;

                $this->dataLoaded = true;
        }

        /**
         * Load image metadata from cache or DB, unless already loaded
         */
        function load() {
                global $wgSharedUploadDBname, $wgUseSharedUploads;
                if ( !$this->dataLoaded ) {
                        if ( !$this->loadFromCache() ) {
                                $this->loadFromDB();
                                if ( !$wgSharedUploadDBname && $wgUseSharedUploads ) {
                                        $this->loadFromFile();
                                } elseif ( $this->fileExists || !$wgUseSharedUploads ) {
                                        // We can do negative caching for local images, because the cache
                                        // will be purged on upload. But we can't do it when shared images
                                        // are enabled, since updates to that won't purge foreign caches.
                                        $this->saveToCache();
                                } 
                        }
                        $this->dataLoaded = true;
                }
        }

        /**
         * Metadata was loaded from the database, but the row had a marker indicating it needs to be
         * upgraded from the 1.4 schema, which had no width, height, bits or type. Upgrade the row.
         */
        function upgradeRow() {
                global $wgDBname, $wgSharedUploadDBname;
                wfProfileIn( __METHOD__ );

                $this->loadFromFile();

                if ( $this->fromSharedDirectory ) {
                        if ( !$wgSharedUploadDBname ) {
                                wfProfileOut( __METHOD__ );
                                return;
                        }

                        // Write to the other DB using selectDB, not database selectors
                        // This avoids breaking replication in MySQL
                        $dbw =& wfGetDB( DB_MASTER, 'commons' );
                        $dbw->selectDB( $wgSharedUploadDBname );
                } else {
                        $dbw =& wfGetDB( DB_MASTER );
                }

                $this->checkDBSchema($dbw);

                list( $major, $minor ) = self::splitMime( $this->mime );

                wfDebug(__METHOD__.': upgrading '.$this->name." to 1.5 schema\n");

                $dbw->update( 'image',
                        array(
                                'img_width' => $this->width,
                                'img_height' => $this->height,
                                'img_bits' => $this->bits,
                                'img_media_type' => $this->type,
                                'img_major_mime' => $major,
                                'img_minor_mime' => $minor,
                                'img_metadata' => $this->metadata,
                        ), array( 'img_name' => $this->name ), __METHOD__
                );
                if ( $this->fromSharedDirectory ) {
                        $dbw->selectDB( $wgDBname );
                }
                wfProfileOut( __METHOD__ );
        }
        
        /**
         * Split an internet media type into its two components; if not
         * a two-part name, set the minor type to 'unknown'.
         *
         * @param $mime "text/html" etc
         * @return array ("text", "html") etc
         */
        static function splitMime( $mime ) {
                if( strpos( $mime, '/' ) !== false ) {
                        return explode( '/', $mime, 2 );
                } else {
                        return array( $mime, 'unknown' );
                }
        }

        /**
         * Return the name of this image
         * @public
         */
        function getName() {
                return $this->name;
        }

        /**
         * Return the associated title object
         * @public
         */
        function getTitle() {
                return $this->title;
        }

        /**
         * Return the URL of the image file
         * @public
         */
        function getURL() {
                if ( !$this->url ) {
                        $this->load();
                        if($this->fileExists) {
                                $this->url = Image::imageUrl( $this->name, $this->fromSharedDirectory );
                        } else {
                                $this->url = '';
                        }
                }
                return $this->url;
        }

        function getViewURL() {
                if( $this->mustRender()) {
                        if( $this->canRender() ) {
                                return $this->createThumb( $this->getWidth() );
                        }
                        else {
                                wfDebug('Image::getViewURL(): supposed to render '.$this->name.' ('.$this->mime."), but can't!\n");
                                return $this->getURL(); #hm... return NULL?
                        }
                } else {
                        return $this->getURL();
                }
        }

        /**
         * Return the image path of the image in the
         * local file system as an absolute path
         * @public
         */
        function getImagePath() {
                $this->load();
                return $this->imagePath;
        }

        /**
         * Return the width of the image
         *
         * Returns -1 if the file specified is not a known image type
         * @public
         */
        function getWidth() {
                $this->load();
                return $this->width;
        }

        /**
         * Return the height of the image
         *
         * Returns -1 if the file specified is not a known image type
         * @public
         */
        function getHeight() {
                $this->load();
                return $this->height;
        }

        /**
         * Return the size of the image file, in bytes
         * @public
         */
        function getSize() {
                $this->load();
                return $this->size;
        }

        /**
         * Returns the mime type of the file.
         */
        function getMimeType() {
                $this->load();
                return $this->mime;
        }

        /**
         * Return the type of the media in the file.
         * Use the value returned by this function with the MEDIATYPE_xxx constants.
         */
        function getMediaType() {
                $this->load();
                return $this->type;
        }

        /**
         * Checks if the file can be presented to the browser as a bitmap.
         *
         * Currently, this checks if the file is an image format
         * that can be converted to a format
         * supported by all browsers (namely GIF, PNG and JPEG),
         * or if it is an SVG image and SVG conversion is enabled.
         *
         * @todo remember the result of this check.
         */
        function canRender() {
                global $wgUseImageMagick;

                if( $this->getWidth()<=0 || $this->getHeight()<=0 ) return false;

                $mime= $this->getMimeType();

                if (!$mime || $mime==='unknown' || $mime==='unknown/unknown') return false;

                #if it's SVG, check if there's a converter enabled
                if ($mime === 'image/svg') {
                        global $wgSVGConverters, $wgSVGConverter;

                        if ($wgSVGConverter && isset( $wgSVGConverters[$wgSVGConverter])) {
                                wfDebug( "Image::canRender: SVG is ready!\n" );
                                return true;
                        } else {
                                wfDebug( "Image::canRender: SVG renderer missing\n" );
                        }
                }

                #image formats available on ALL browsers
                if (  $mime === 'image/gif'
                   || $mime === 'image/png'
                   || $mime === 'image/jpeg' ) return true;

                #image formats that can be converted to the above formats
                if ($wgUseImageMagick) {
                        #convertable by ImageMagick (there are more...)
                        if ( $mime === 'image/vnd.wap.wbmp'
                          || $mime === 'image/x-xbitmap'
                          || $mime === 'image/x-xpixmap'
                          #|| $mime === 'image/x-icon'   #file may be split into multiple parts
                          || $mime === 'image/x-portable-anymap'
                          || $mime === 'image/x-portable-bitmap'
                          || $mime === 'image/x-portable-graymap'
                          || $mime === 'image/x-portable-pixmap'
                          #|| $mime === 'image/x-photoshop'  #this takes a lot of CPU and RAM!
                          || $mime === 'image/x-rgb'
                          || $mime === 'image/x-bmp'
                          || $mime === 'image/tiff' ) return true;
                }
                else {
                        #convertable by the PHP GD image lib
                        if ( $mime === 'image/vnd.wap.wbmp'
                          || $mime === 'image/x-xbitmap' ) return true;
                }

                return false;
        }


        /**
         * Return true if the file is of a type that can't be directly
         * rendered by typical browsers and needs to be re-rasterized.
         *
         * This returns true for everything but the bitmap types
         * supported by all browsers, i.e. JPEG; GIF and PNG. It will
         * also return true for any non-image formats.
         *
         * @return bool
         */
        function mustRender() {
                $mime= $this->getMimeType();

                if (  $mime === "image/gif"
                   || $mime === "image/png"
                   || $mime === "image/jpeg" ) return false;

                return true;
        }

        /**
         * Determines if this media file may be shown inline on a page.
         *
         * This is currently synonymous to canRender(), but this could be
         * extended to also allow inline display of other media,
         * like flash animations or videos. If you do so, please keep in mind that
         * that could be a security risk.
         */
        function allowInlineDisplay() {
                return $this->canRender();
        }

        /**
         * Determines if this media file is in a format that is unlikely to
         * contain viruses or malicious content. It uses the global
         * $wgTrustedMediaFormats list to determine if the file is safe.
         *
         * This is used to show a warning on the description page of non-safe files.
         * It may also be used to disallow direct [[media:...]] links to such files.
         *
         * Note that this function will always return true if allowInlineDisplay()
         * or isTrustedFile() is true for this file.
         */
        function isSafeFile() {
                if ($this->allowInlineDisplay()) return true;
                if ($this->isTrustedFile()) return true;

                global $wgTrustedMediaFormats;

                $type= $this->getMediaType();
                $mime= $this->getMimeType();
                #wfDebug("Image::isSafeFile: type= $type, mime= $mime\n");

                if (!$type || $type===MEDIATYPE_UNKNOWN) return false; #unknown type, not trusted
                if ( in_array( $type, $wgTrustedMediaFormats) ) return true;

                if ($mime==="unknown/unknown") return false; #unknown type, not trusted
                if ( in_array( $mime, $wgTrustedMediaFormats) ) return true;

                return false;
        }

        /** Returns true if the file is flagged as trusted. Files flagged that way
        * can be linked to directly, even if that is not allowed for this type of
        * file normally.
        *
        * This is a dummy function right now and always returns false. It could be
        * implemented to extract a flag from the database. The trusted flag could be
        * set on upload, if the user has sufficient privileges, to bypass script-
        * and html-filters. It may even be coupled with cryptographics signatures
        * or such.
        */
        function isTrustedFile() {
                #this could be implemented to check a flag in the databas,
                #look for signatures, etc
                return false;
        }

        /**
         * Return the escapeLocalURL of this image
         * @public
         */
        function getEscapeLocalURL() {
                $this->getTitle();
                return $this->title->escapeLocalURL();
        }

        /**
         * Return the escapeFullURL of this image
         * @public
         */
        function getEscapeFullURL() {
                $this->getTitle();
                return $this->title->escapeFullURL();
        }

        /**
         * Return the URL of an image, provided its name.
         *
         * @param string $name  Name of the image, without the leading "Image:"
         * @param boolean $fromSharedDirectory  Should this be in $wgSharedUploadPath?
         * @return string URL of $name image
         * @public
         * @static
         */
        function imageUrl( $name, $fromSharedDirectory = false ) {
                global $wgUploadPath,$wgUploadBaseUrl,$wgSharedUploadPath;
                if($fromSharedDirectory) {
                        $base = '';
                        $path = $wgSharedUploadPath;
                } else {
                        $base = $wgUploadBaseUrl;
                        $path = $wgUploadPath;
                }
                $url = "{$base}{$path}" .  wfGetHashPath($name, $fromSharedDirectory) . "{$name}";
                return wfUrlencode( $url );
        }

        /**
         * Returns true if the image file exists on disk.
         * @return boolean Whether image file exist on disk.
         * @public
         */
        function exists() {
                $this->load();
                return $this->fileExists;
        }

        /**
         * @todo document
         * @private
         */
        function thumbUrl( $width, $subdir='thumb') {
                global $wgUploadPath, $wgUploadBaseUrl, $wgSharedUploadPath;
                global $wgSharedThumbnailScriptPath, $wgThumbnailScriptPath;

                // Generate thumb.php URL if possible
                $script = false;
                $url = false;

                if ( $this->fromSharedDirectory ) {
                        if ( $wgSharedThumbnailScriptPath ) {
                                $script = $wgSharedThumbnailScriptPath;
                        }
                } else {
                        if ( $wgThumbnailScriptPath ) {
                                $script = $wgThumbnailScriptPath;
                        }
                }
                if ( $script ) {
                        $url = $script . '?f=' . urlencode( $this->name ) . '&w=' . urlencode( $width );
                        if( $this->mustRender() ) {
                                $url.= '&r=1';
                        }
                } else {
                        $name = $this->thumbName( $width );
                        if($this->fromSharedDirectory) {
                                $base = '';
                                $path = $wgSharedUploadPath;
                        } else {
                                $base = $wgUploadBaseUrl;
                                $path = $wgUploadPath;
                        }
                        if ( Image::isHashed( $this->fromSharedDirectory ) ) {
                                $url = "{$base}{$path}/{$subdir}" .
                                wfGetHashPath($this->name, $this->fromSharedDirectory)
                                . $this->name.'/'.$name;
                                $url = wfUrlencode( $url );
                        } else {
                                $url = "{$base}{$path}/{$subdir}/{$name}";
                        }
                }
                return array( $script !== false, $url );
        }

        /**
         * Return the file name of a thumbnail of the specified width
         *
         * @param integer $width        Width of the thumbnail image
         * @param boolean $shared       Does the thumbnail come from the shared repository?
         * @private
         */
        function thumbName( $width ) {
                $thumb = $width."px-".$this->name;

                if( $this->mustRender() ) {
                        if( $this->canRender() ) {
                                # Rasterize to PNG (for SVG vector images, etc)
                                $thumb .= '.png';
                        }
                        else {
                                #should we use iconThumb here to get a symbolic thumbnail?
                                #or should we fail with an internal error?
                                return NULL; //can't make bitmap
                        }
                }
                return $thumb;
        }

        /**
         * Create a thumbnail of the image having the specified width/height.
         * The thumbnail will not be created if the width is larger than the
         * image's width. Let the browser do the scaling in this case.
         * The thumbnail is stored on disk and is only computed if the thumbnail
         * file does not exist OR if it is older than the image.
         * Returns the URL.
         *
         * Keeps aspect ratio of original image. If both width and height are
         * specified, the generated image will be no bigger than width x height,
         * and will also have correct aspect ratio.
         *
         * @param integer $width        maximum width of the generated thumbnail
         * @param integer $height       maximum height of the image (optional)
         * @public
         */
        function createThumb( $width, $height=-1 ) {
                $thumb = $this->getThumbnail( $width, $height );
                if( is_null( $thumb ) ) return '';
                return $thumb->getUrl();
        }

        /**
         * As createThumb, but returns a ThumbnailImage object. This can
         * provide access to the actual file, the real size of the thumb,
         * and can produce a convenient <img> tag for you.
         *
         * For non-image formats, this may return a filetype-specific icon.
         *
         * @param integer $width        maximum width of the generated thumbnail
         * @param integer $height       maximum height of the image (optional)
         * @param boolean $render       True to render the thumbnail if it doesn't exist,
         *                              false to just return the URL
         *
         * @return ThumbnailImage or null on failure
         * @public
         */
        function getThumbnail( $width, $height=-1, $render = true ) {
                wfProfileIn( __METHOD__ );
                if ($this->canRender()) {
                        if ( $height > 0 ) {
                                $this->load();
                                if ( $width > $this->width * $height / $this->height ) {
                                        $width = wfFitBoxWidth( $this->width, $this->height, $height );
                                }
                        }
                        if ( $render ) {
                                $thumb = $this->renderThumb( $width );
                        } else {
                                // Don't render, just return the URL
                                if ( $this->validateThumbParams( $width, $height ) ) {
                                        if ( !$this->mustRender() && $width == $this->width && $height == $this->height ) {
                                                $url = $this->getURL();
                                        } else {
                                                list( $isScriptUrl, $url ) = $this->thumbUrl( $width );
                                        }
                                        $thumb = new ThumbnailImage( $url, $width, $height );
                                } else {
                                        $thumb = null;
                                }
                        }
                } else {
                        // not a bitmap or renderable image, don't try.
                        $thumb = $this->iconThumb();
                }
                wfProfileOut( __METHOD__ );
                return $thumb;
        }

        /**
         * @return ThumbnailImage
         */
        function iconThumb() {
                global $wgStylePath, $wgStyleDirectory;

                $try = array( 'fileicon-' . $this->extension . '.png', 'fileicon.png' );
                foreach( $try as $icon ) {
                        $path = '/common/images/icons/' . $icon;
                        $filepath = $wgStyleDirectory . $path;
                        if( file_exists( $filepath ) ) {
                                return new ThumbnailImage( $wgStylePath . $path, 120, 120 );
                        }
                }
                return null;
        }

        /**
         * Validate thumbnail parameters and fill in the correct height
         *
         * @param integer &$width Specified width (input/output)
         * @param integer &$height Height (output only)
         * @return false to indicate that an error should be returned to the user. 
         */
        function validateThumbParams( &$width, &$height ) {
                global $wgSVGMaxSize, $wgMaxImageArea;
                
                $this->load();

                if ( ! $this->exists() )
                {
                        # If there is no image, there will be no thumbnail
                        return false;
                }
                
                $width = intval( $width );
                
                # Sanity check $width
                if( $width <= 0 || $this->width <= 0) {
                        # BZZZT
                        return false;
                }

                # Don't thumbnail an image so big that it will fill hard drives and send servers into swap
                # JPEG has the handy property of allowing thumbnailing without full decompression, so we make
                # an exception for it.
                if ( $this->getMediaType() == MEDIATYPE_BITMAP &&
                        $this->getMimeType() !== 'image/jpeg' &&
                        $this->width * $this->height > $wgMaxImageArea )
                {
                        return false;
                }

                # Don't make an image bigger than the source, or wgMaxSVGSize for SVGs
                if ( $this->mustRender() ) {
                        $width = min( $width, $wgSVGMaxSize );
                } elseif ( $width > $this->width - 1 ) {
                        $width = $this->width;
                        $height = $this->height;
                        return true;
                }

                $height = round( $this->height * $width / $this->width );
                return true;
        }
        
        /**
         * Create a thumbnail of the image having the specified width.
         * The thumbnail will not be created if the width is larger than the
         * image's width. Let the browser do the scaling in this case.
         * The thumbnail is stored on disk and is only computed if the thumbnail
         * file does not exist OR if it is older than the image.
         * Returns an object which can return the pathname, URL, and physical
         * pixel size of the thumbnail -- or null on failure.
         *
         * @return ThumbnailImage or null on failure
         * @private
         */
        function renderThumb( $width, $useScript = true ) {
                global $wgUseSquid, $wgThumbnailEpoch;

                wfProfileIn( __METHOD__ );

                $this->load();
                $height = -1;
                if ( !$this->validateThumbParams( $width, $height ) ) {
                        # Validation error
                        wfProfileOut( __METHOD__ );
                        return null;
                }

                if ( !$this->mustRender() && $width == $this->width && $height == $this->height ) {
                        # validateThumbParams (or the user) wants us to return the unscaled image
                        $thumb = new ThumbnailImage( $this->getURL(), $width, $height );
                        wfProfileOut( __METHOD__ );
                        return $thumb;
                }
                
                list( $isScriptUrl, $url ) = $this->thumbUrl( $width );
                if ( $isScriptUrl && $useScript ) {
                        // Use thumb.php to render the image
                        $thumb = new ThumbnailImage( $url, $width, $height );
                        wfProfileOut( __METHOD__ );
                        return $thumb;
                }

                $thumbName = $this->thumbName( $width, $this->fromSharedDirectory );
                $thumbDir = wfImageThumbDir( $this->name, $this->fromSharedDirectory );
                $thumbPath = $thumbDir.'/'.$thumbName;

                if ( is_dir( $thumbPath ) ) {
                        // Directory where file should be
                        // This happened occasionally due to broken migration code in 1.5
                        // Rename to broken-*
                        global $wgUploadDirectory;
                        for ( $i = 0; $i < 100 ; $i++ ) {
                                $broken = "$wgUploadDirectory/broken-$i-$thumbName";
                                if ( !file_exists( $broken ) ) {
                                        rename( $thumbPath, $broken );
                                        break;
                                }
                        }
                        // Code below will ask if it exists, and the answer is now no
                        clearstatcache();
                }

                $done = true;
                if ( !file_exists( $thumbPath ) ||
                        filemtime( $thumbPath ) < wfTimestamp( TS_UNIX, $wgThumbnailEpoch ) ) 
                {
                        // Create the directory if it doesn't exist
                        if ( is_file( $thumbDir ) ) {
                                // File where thumb directory should be, destroy if possible
                                @unlink( $thumbDir );
                        }
                        wfMkdirParents( $thumbDir );
                        
                        $oldThumbPath = wfDeprecatedThumbDir( $thumbName, 'thumb', $this->fromSharedDirectory ).
                                '/'.$thumbName;
                        $done = false;

                        // Migration from old directory structure
                        if ( is_file( $oldThumbPath ) ) {
                                if ( filemtime($oldThumbPath) >= filemtime($this->imagePath) ) {
                                        if ( file_exists( $thumbPath ) ) {
                                                if ( !is_dir( $thumbPath ) ) {
                                                        // Old image in the way of rename
                                                        unlink( $thumbPath );
                                                } else {
                                                        // This should have been dealt with already
                                                        throw new MWException( "Directory where image should be: $thumbPath" );
                                                }
                                        }
                                        // Rename the old image into the new location
                                        rename( $oldThumbPath, $thumbPath );
                                        $done = true;
                                } else {
                                        unlink( $oldThumbPath );
                                }
                        }
                        if ( !$done ) {
                                $this->lastError = $this->reallyRenderThumb( $thumbPath, $width, $height );
                                if ( $this->lastError === true ) {
                                        $done = true;
                                } elseif( $GLOBALS['wgIgnoreImageErrors'] ) {
                                        // Log the error but output anyway.
                                        // With luck it's a transitory error...
                                        $done = true;
                                }

                                # Purge squid
                                # This has to be done after the image is updated and present for all machines on NFS,
                                # or else the old version might be stored into the squid again
                                if ( $wgUseSquid ) {
                                        $urlArr = array( $url );
                                        wfPurgeSquidServers($urlArr);
                                }
                        }
                }

                if ( $done ) {
                        $thumb = new ThumbnailImage( $url, $width, $height, $thumbPath );
                } else {
                        $thumb = null;
                }
                wfProfileOut( __METHOD__ );
                return $thumb;
        } // END OF function renderThumb

        /**
         * Really render a thumbnail
         * Call this only for images for which canRender() returns true.
         *
         * @param string $thumbPath Path to thumbnail
         * @param int $width Desired width in pixels
         * @param int $height Desired height in pixels
         * @return bool True on error, false or error string on failure.
         * @private
         */
        function reallyRenderThumb( $thumbPath, $width, $height ) {
                global $wgSVGConverters, $wgSVGConverter;
                global $wgUseImageMagick, $wgImageMagickConvertCommand;
                global $wgCustomConvertCommand;

                $this->load();

                $err = false;
                $cmd = "";
                $retval = 0;
                
                if( $this->mime === "image/svg" ) {
                        #Right now we have only SVG

                        global $wgSVGConverters, $wgSVGConverter;
                        if( isset( $wgSVGConverters[$wgSVGConverter] ) ) {
                                global $wgSVGConverterPath;
                                $cmd = str_replace(
                                        array( '$path/', '$width', '$height', '$input', '$output' ),
                                        array( $wgSVGConverterPath ? "$wgSVGConverterPath/" : "",
                                                   intval( $width ),
                                                   intval( $height ),
                                                   wfEscapeShellArg( $this->imagePath ),
                                                   wfEscapeShellArg( $thumbPath ) ),
                                        $wgSVGConverters[$wgSVGConverter] );
                                wfProfileIn( 'rsvg' );
                                wfDebug( "reallyRenderThumb SVG: $cmd\n" );
                                $err = wfShellExec( $cmd, $retval );
                                wfProfileOut( 'rsvg' );
                        }
                } elseif ( $wgUseImageMagick ) {
                        # use ImageMagick
                        
                        if ( $this->mime == 'image/jpeg' ) {
                                $quality = "-quality 80"; // 80%
                        } elseif ( $this->mime == 'image/png' ) {
                                $quality = "-quality 95"; // zlib 9, adaptive filtering
                        } else {
                                $quality = ''; // default
                        }

                        # Specify white background color, will be used for transparent images
                        # in Internet Explorer/Windows instead of default black.

                        # Note, we specify "-size {$width}" and NOT "-size {$width}x{$height}".
                        # It seems that ImageMagick has a bug wherein it produces thumbnails of
                        # the wrong size in the second case.
                        
                        $cmd  =  wfEscapeShellArg($wgImageMagickConvertCommand) .
                                " {$quality} -background white -size {$width} ".
                                wfEscapeShellArg($this->imagePath) .
                                // Coalesce is needed to scale animated GIFs properly (bug 1017).
                                ' -coalesce ' .
                                // For the -resize option a "!" is needed to force exact size,
                                // or ImageMagick may decide your ratio is wrong and slice off
                                // a pixel.
                                " -resize " . wfEscapeShellArg( "{$width}x{$height}!" ) .
                                " -depth 8 " .
                                wfEscapeShellArg($thumbPath) . " 2>&1";
                        wfDebug("reallyRenderThumb: running ImageMagick: $cmd\n");
                        wfProfileIn( 'convert' );
                        $err = wfShellExec( $cmd, $retval );
                        wfProfileOut( 'convert' );
                } elseif( $wgCustomConvertCommand ) {
                        # Use a custom convert command
                        # Variables: %s %d %w %h
                        $src = wfEscapeShellArg( $this->imagePath );
                        $dst = wfEscapeShellArg( $thumbPath );
                        $cmd = $wgCustomConvertCommand;
                        $cmd = str_replace( '%s', $src, str_replace( '%d', $dst, $cmd ) ); # Filenames
                        $cmd = str_replace( '%h', $height, str_replace( '%w', $width, $cmd ) ); # Size
                        wfDebug( "reallyRenderThumb: Running custom convert command $cmd\n" );
                        wfProfileIn( 'convert' );
                        $err = wfShellExec( $cmd, $retval );
                        wfProfileOut( 'convert' );
                } else {
                        # Use PHP's builtin GD library functions.
                        #
                        # First find out what kind of file this is, and select the correct
                        # input routine for this.

                        $typemap = array(
                                'image/gif'          => array( 'imagecreatefromgif',  'palette',   'imagegif'  ),
                                'image/jpeg'         => array( 'imagecreatefromjpeg', 'truecolor', array( &$this, 'imageJpegWrapper' ) ),
                                'image/png'          => array( 'imagecreatefrompng',  'bits',      'imagepng'  ),
                                'image/vnd.wap.wmbp' => array( 'imagecreatefromwbmp', 'palette',   'imagewbmp'  ),
                                'image/xbm'          => array( 'imagecreatefromxbm',  'palette',   'imagexbm'  ),
                        );
                        if( !isset( $typemap[$this->mime] ) ) {
                                $err = 'Image type not supported';
                                wfDebug( "$err\n" );
                                return $err;
                        }
                        list( $loader, $colorStyle, $saveType ) = $typemap[$this->mime];

                        if( !function_exists( $loader ) ) {
                                $err = "Incomplete GD library configuration: missing function $loader";
                                wfDebug( "$err\n" );
                                return $err;
                        }
                        if( $colorStyle == 'palette' ) {
                                $truecolor = false;
                        } elseif( $colorStyle == 'truecolor' ) {
                                $truecolor = true;
                        } elseif( $colorStyle == 'bits' ) {
                                $truecolor = ( $this->bits > 8 );
                        }

                        $src_image = call_user_func( $loader, $this->imagePath );
                        if ( $truecolor ) {
                                $dst_image = imagecreatetruecolor( $width, $height );
                        } else {
                                $dst_image = imagecreate( $width, $height );
                        }
                        imagecopyresampled( $dst_image, $src_image,
                                                0,0,0,0,
                                                $width, $height, $this->width, $this->height );
                        call_user_func( $saveType, $dst_image, $thumbPath );
                        imagedestroy( $dst_image );
                        imagedestroy( $src_image );
                }

                #
                # Check for zero-sized thumbnails. Those can be generated when
                # no disk space is available or some other error occurs
                #
                if( file_exists( $thumbPath ) ) {
                        $thumbstat = stat( $thumbPath );
                        if( $thumbstat['size'] == 0 || $retval != 0 ) {
                                wfDebugLog( 'thumbnail',
                                        sprintf( 'Removing bad %d-byte thumbnail "%s"',
                                                $thumbstat['size'], $thumbPath ) );
                                unlink( $thumbPath );
                        }
                }
                if ( $retval != 0 ) {
                        wfDebugLog( 'thumbnail',
                                sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
                                        wfHostname(), $retval, trim($err), $cmd ) );
                        return wfMsg( 'thumbnail_error', $err );
                } else {
                        return true;
                }
        }

        function getLastError() {
                return $this->lastError;
        }

        function imageJpegWrapper( $dst_image, $thumbPath ) {
                imageinterlace( $dst_image );
                imagejpeg( $dst_image, $thumbPath, 95 );
        }

        /**
         * Get all thumbnail names previously generated for this image
         */
        function getThumbnails( $shared = false ) {
                if ( Image::isHashed( $shared ) ) {
                        $this->load();
                        $files = array();
                        $dir = wfImageThumbDir( $this->name, $shared );

                        // This generates an error on failure, hence the @
                        $handle = @opendir( $dir );

                        if ( $handle ) {
                                while ( false !== ( $file = readdir($handle) ) ) {
                                        if ( $file{0} != '.' ) {
                                                $files[] = $file;
                                        }
                                }
                                closedir( $handle );
                        }
                } else {
                        $files = array();
                }

                return $files;
        }

        /**
         * Refresh metadata in memcached, but don't touch thumbnails or squid
         */
        function purgeMetadataCache() {
                clearstatcache();
                $this->loadFromFile();
                $this->saveToCache();
        }

        /**
         * Delete all previously generated thumbnails, refresh metadata in memcached and purge the squid
         */
        function purgeCache( $archiveFiles = array(), $shared = false ) {
                global $wgUseSquid;

                // Refresh metadata cache
                $this->purgeMetadataCache();

                // Delete thumbnails
                $files = $this->getThumbnails( $shared );
                $dir = wfImageThumbDir( $this->name, $shared );
                $urls = array();
                foreach ( $files as $file ) {
                        if ( preg_match( '/^(\d+)px/', $file, $m ) ) {
                                $urls[] = $this->thumbUrl( $m[1], $this->fromSharedDirectory );
                                @unlink( "$dir/$file" );
                        }
                }

                // Purge the squid
                if ( $wgUseSquid ) {
                        $urls[] = $this->getViewURL();
                        foreach ( $archiveFiles as $file ) {
                                $urls[] = wfImageArchiveUrl( $file );
                        }
                        wfPurgeSquidServers( $urls );
                }
        }
        
        /**
         * Purge the image description page, but don't go after
         * pages using the image. Use when modifying file history
         * but not the current data.
         */
        function purgeDescription() {
                $page = Title::makeTitle( NS_IMAGE, $this->name );
                $page->invalidateCache();
                $page->purgeSquid();
        }
        
        /**
         * Purge metadata and all affected pages when the image is created,
         * deleted, or majorly updated. A set of additional URLs may be
         * passed to purge, such as specific image files which have changed.
         * @param $urlArray array
         */
        function purgeEverything( $urlArr=array() ) {
                // Delete thumbnails and refresh image metadata cache
                $this->purgeCache();
                $this->purgeDescription();
                
                // Purge cache of all pages using this image
                $update = new HTMLCacheUpdate( $this->getTitle(), 'imagelinks' );
                $update->doUpdate();
        }

        function checkDBSchema(&$db) {
                static $checkDone = false;
                global $wgCheckDBSchema;
                if (!$wgCheckDBSchema || $checkDone) {
                        return;
                }
                # img_name must be unique
                if ( !$db->indexUnique( 'image', 'img_name' ) && !$db->indexExists('image','PRIMARY') ) {
                        throw new MWException( 'Database schema not up to date, please run maintenance/archives/patch-image_name_unique.sql' );
                }
                $checkDone = true;

                # new fields must exist
                # 
                # Not really, there's hundreds of checks like this that we could do and they're all pointless, because 
                # if the fields are missing, the database will loudly report a query error, the first time you try to do 
                # something. The only reason I put the above schema check in was because the absence of that particular
                # index would lead to an annoying subtle bug. No error message, just some very odd behaviour on duplicate
                # uploads. -- TS
                /*
                if ( !$db->fieldExists( 'image', 'img_media_type' )
                  || !$db->fieldExists( 'image', 'img_metadata' )
                  || !$db->fieldExists( 'image', 'img_width' ) ) {

                        throw new MWException( 'Database schema not up to date, please run maintenance/update.php' );
                 }
                 */
        }

        /**
         * Return the image history of this image, line by line.
         * starts with current version, then old versions.
         * uses $this->historyLine to check which line to return:
         *  0      return line for current version
         *  1      query for old versions, return first one
         *  2, ... return next old version from above query
         *
         * @public
         */
        function nextHistoryLine() {
                $dbr =& wfGetDB( DB_SLAVE );

                $this->checkDBSchema($dbr);

                if ( $this->historyLine == 0 ) {// called for the first time, return line from cur
                        $this->historyRes = $dbr->select( 'image',
                                array(
                                        'img_size',
                                        'img_description',
                                        'img_user','img_user_text',
                                        'img_timestamp',
                                        'img_width',
                                        'img_height',
                                        "'' AS oi_archive_name"
                                ),
                                array( 'img_name' => $this->title->getDBkey() ),
                                __METHOD__
                        );
                        if ( 0 == wfNumRows( $this->historyRes ) ) {
                                return FALSE;
                        }
                } else if ( $this->historyLine == 1 ) {
                        $this->historyRes = $dbr->select( 'oldimage',
                                array(
                                        'oi_size AS img_size',
                                        'oi_description AS img_description',
                                        'oi_user AS img_user',
                                        'oi_user_text AS img_user_text',
                                        'oi_timestamp AS img_timestamp',
                                        'oi_width as img_width',
                                        'oi_height as img_height',
                                        'oi_archive_name'
                                ),
                                array( 'oi_name' => $this->title->getDBkey() ),
                                __METHOD__,
                                array( 'ORDER BY' => 'oi_timestamp DESC' )
                        );
                }
                $this->historyLine ++;

                return $dbr->fetchObject( $this->historyRes );
        }

        /**
         * Reset the history pointer to the first element of the history
         * @public
         */
        function resetHistory() {
                $this->historyLine = 0;
        }

        /**
        * Return the full filesystem path to the file. Note that this does
        * not mean that a file actually exists under that location.
        *
        * This path depends on whether directory hashing is active or not,
        * i.e. whether the images are all found in the same directory,
        * or in hashed paths like /images/3/3c.
        *
        * @public
        * @param boolean $fromSharedDirectory Return the path to the file
        *   in a shared repository (see $wgUseSharedRepository and related
        *   options in DefaultSettings.php) instead of a local one.
        *
        */
        function getFullPath( $fromSharedRepository = false ) {
                global $wgUploadDirectory, $wgSharedUploadDirectory;

                $dir      = $fromSharedRepository ? $wgSharedUploadDirectory :
                                                    $wgUploadDirectory;

                // $wgSharedUploadDirectory may be false, if thumb.php is used
                if ( $dir ) {
                        $fullpath = $dir . wfGetHashPath($this->name, $fromSharedRepository) . $this->name;
                } else {
                        $fullpath = false;
                }

                return $fullpath;
        }

        /**
         * @return bool
         * @static
         */
        public static function isHashed( $shared ) {
                global $wgHashedUploadDirectory, $wgHashedSharedUploadDirectory;
                return $shared ? $wgHashedSharedUploadDirectory : $wgHashedUploadDirectory;
        }

        /**
         * Record an image upload in the upload log and the image table
         */
        function recordUpload( $oldver, $desc, $license = '', $copyStatus = '', $source = '', $watch = false ) {
                global $wgUser, $wgUseCopyrightUpload;

                $dbw =& wfGetDB( DB_MASTER );

                $this->checkDBSchema($dbw);

                // Delete thumbnails and refresh the metadata cache
                $this->purgeCache();

                // Fail now if the image isn't there
                if ( !$this->fileExists || $this->fromSharedDirectory ) {
                        wfDebug( "Image::recordUpload: File ".$this->imagePath." went missing!\n" );
                        return false;
                }

                if ( $wgUseCopyrightUpload ) {
                        if ( $license != '' ) {
                                $licensetxt = '== ' . wfMsgForContent( 'license' ) . " ==\n" . '{{' . $license . '}}' . "\n";
                        }
                        $textdesc = '== ' . wfMsg ( 'filedesc' ) . " ==\n" . $desc . "\n" .
                          '== ' . wfMsgForContent ( 'filestatus' ) . " ==\n" . $copyStatus . "\n" .
                          "$licensetxt" .
                          '== ' . wfMsgForContent ( 'filesource' ) . " ==\n" . $source ;
                } else {
                        if ( $license != '' ) {
                                $filedesc = $desc == '' ? '' : '== ' . wfMsg ( 'filedesc' ) . " ==\n" . $desc . "\n";
                                 $textdesc = $filedesc .
                                         '== ' . wfMsgForContent ( 'license' ) . " ==\n" . '{{' . $license . '}}' . "\n";
                        } else {
                                $textdesc = $desc;
                        }
                }

                $now = $dbw->timestamp();

                #split mime type
                if (strpos($this->mime,'/')!==false) {
                        list($major,$minor)= explode('/',$this->mime,2);
                }
                else {
                        $major= $this->mime;
                        $minor= "unknown";
                }

                # Test to see if the row exists using INSERT IGNORE
                # This avoids race conditions by locking the row until the commit, and also
                # doesn't deadlock. SELECT FOR UPDATE causes a deadlock for every race condition.
                $dbw->insert( 'image',
                        array(
                                'img_name' => $this->name,
                                'img_size'=> $this->size,
                                'img_width' => intval( $this->width ),
                                'img_height' => intval( $this->height ),
                                'img_bits' => $this->bits,
                                'img_media_type' => $this->type,
                                'img_major_mime' => $major,
                                'img_minor_mime' => $minor,
                                'img_timestamp' => $now,
                                'img_description' => $desc,
                                'img_user' => $wgUser->getID(),
                                'img_user_text' => $wgUser->getName(),
                                'img_metadata' => $this->metadata,
                        ),
                        __METHOD__,
                        'IGNORE'
                );

                if( $dbw->affectedRows() == 0 ) {
                        # Collision, this is an update of an image
                        # Insert previous contents into oldimage
                        $dbw->insertSelect( 'oldimage', 'image',
                                array(
                                        'oi_name' => 'img_name',
                                        'oi_archive_name' => $dbw->addQuotes( $oldver ),
                                        'oi_size' => 'img_size',
                                        'oi_width' => 'img_width',
                                        'oi_height' => 'img_height',
                                        'oi_bits' => 'img_bits',
                                        'oi_timestamp' => 'img_timestamp',
                                        'oi_description' => 'img_description',
                                        'oi_user' => 'img_user',
                                        'oi_user_text' => 'img_user_text',
                                ), array( 'img_name' => $this->name ), __METHOD__
                        );

                        # Update the current image row
                        $dbw->update( 'image',
                                array( /* SET */
                                        'img_size' => $this->size,
                                        'img_width' => intval( $this->width ),
                                        'img_height' => intval( $this->height ),
                                        'img_bits' => $this->bits,
                                        'img_media_type' => $this->type,
                                        'img_major_mime' => $major,
                                        'img_minor_mime' => $minor,
                                        'img_timestamp' => $now,
                                        'img_description' => $desc,
                                        'img_user' => $wgUser->getID(),
                                        'img_user_text' => $wgUser->getName(),
                                        'img_metadata' => $this->metadata,
                                ), array( /* WHERE */
                                        'img_name' => $this->name
                                ), __METHOD__
                        );
                } else {
                        # This is a new image
                        # Update the image count
                        $site_stats = $dbw->tableName( 'site_stats' );
                        $dbw->query( "UPDATE $site_stats SET ss_images=ss_images+1", __METHOD__ );
                }

                $descTitle = $this->getTitle();
                $article = new Article( $descTitle );
                $minor = false;
                $watch = $watch || $wgUser->isWatched( $descTitle );
                $suppressRC = true; // There's already a log entry, so don't double the RC load

                if( $descTitle->exists() ) {
                        // TODO: insert a null revision into the page history for this update.
                        if( $watch ) {
                                $wgUser->addWatch( $descTitle );
                        }

                        # Invalidate the cache for the description page
                        $descTitle->invalidateCache();
                        $descTitle->purgeSquid();
                } else {
                        // New image; create the description page.
                        $article->insertNewArticle( $textdesc, $desc, $minor, $watch, $suppressRC );
                }

                # Add the log entry
                $log = new LogPage( 'upload' );
                $log->addEntry( 'upload', $descTitle, $desc );

                # Commit the transaction now, in case something goes wrong later
                # The most important thing is that images don't get lost, especially archives
                $dbw->immediateCommit();

                # Invalidate cache for all pages using this image
                $update = new HTMLCacheUpdate( $this->getTitle(), 'imagelinks' );
                $update->doUpdate();

                return true;
        }

        /**
         * Get an array of Title objects which are articles which use this image
         * Also adds their IDs to the link cache
         *
         * This is mostly copied from Title::getLinksTo()
         *
         * @deprecated Use HTMLCacheUpdate, this function uses too much memory
         */
        function getLinksTo( $options = '' ) {
                wfProfileIn( __METHOD__ );

                if ( $options ) {
                        $db =& wfGetDB( DB_MASTER );
                } else {
                        $db =& wfGetDB( DB_SLAVE );
                }
                $linkCache =& LinkCache::singleton();

                extract( $db->tableNames( 'page', 'imagelinks' ) );
                $encName = $db->addQuotes( $this->name );
                $sql = "SELECT page_namespace,page_title,page_id FROM $page,$imagelinks WHERE page_id=il_from AND il_to=$encName $options";
                $res = $db->query( $sql, __METHOD__ );

                $retVal = array();
                if ( $db->numRows( $res ) ) {
                        while ( $row = $db->fetchObject( $res ) ) {
                                if ( $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title ) ) {
                                        $linkCache->addGoodLinkObj( $row->page_id, $titleObj );
                                        $retVal[] = $titleObj;
                                }
                        }
                }
                $db->freeResult( $res );
                wfProfileOut( __METHOD__ );
                return $retVal;
        }
        
        /**
         * Retrive Exif data from the file and prune unrecognized tags
         * and/or tags with invalid contents
         *
         * @param $filename
         * @return array
         */
        private function retrieveExifData( $filename ) {
                global $wgShowEXIF;
                
                /*
                if ( $this->getMimeType() !== "image/jpeg" )
                        return array();
                */

                if( $wgShowEXIF && file_exists( $filename ) ) {
                        $exif = new Exif( $filename );
                        return $exif->getFilteredData();
                }
                
                return array();
        }

        function getExifData() {
                global $wgRequest;
                if ( $this->metadata === '0' )
                        return array();

                $purge = $wgRequest->getVal( 'action' ) == 'purge';
                $ret = unserialize( $this->metadata );

                $oldver = isset( $ret['MEDIAWIKI_EXIF_VERSION'] ) ? $ret['MEDIAWIKI_EXIF_VERSION'] : 0;
                $newver = Exif::version();

                if ( !count( $ret ) || $purge || $oldver != $newver ) {
                        $this->purgeMetadataCache();
                        $this->updateExifData( $newver );
                }
                if ( isset( $ret['MEDIAWIKI_EXIF_VERSION'] ) )
                        unset( $ret['MEDIAWIKI_EXIF_VERSION'] );
                $format = new FormatExif( $ret );

                return $format->getFormattedData();
        }

        function updateExifData( $version ) {
                if ( $this->getImagePath() === false ) # Not a local image
                        return;

                # Get EXIF data from image
                $exif = $this->retrieveExifData( $this->imagePath );
                if ( count( $exif ) ) {
                        $exif['MEDIAWIKI_EXIF_VERSION'] = $version;
                        $this->metadata = serialize( $exif );
                } else {
                        $this->metadata = '0';
                }

                # Update EXIF data in database
                $dbw =& wfGetDB( DB_MASTER );

                $this->checkDBSchema($dbw);

                $dbw->update( 'image',
                        array( 'img_metadata' => $this->metadata ),
                        array( 'img_name' => $this->name ),
                        __METHOD__
                );
        }

        /**
         * Returns true if the image does not come from the shared
         * image repository.
         *
         * @return bool
         */
        function isLocal() {
                return !$this->fromSharedDirectory;
        }
        
        /**
         * Was this image ever deleted from the wiki?
         *
         * @return bool
         */
        function wasDeleted() {
                $title = Title::makeTitle( NS_IMAGE, $this->name );
                return ( $title->isDeleted() > 0 );
        }
        
        /**
         * Delete all versions of the image.
         *
         * Moves the files into an archive directory (or deletes them)
         * and removes the database rows.
         *
         * Cache purging is done; logging is caller's responsibility.
         *
         * @param $reason
         * @return true on success, false on some kind of failure
         */
        function delete( $reason ) {
                $transaction = new FSTransaction();
                $urlArr = array( $this->getURL() );
                
                if( !FileStore::lock() ) {
                        wfDebug( __METHOD__.": failed to acquire file store lock, aborting\n" );
                        return false;
                }
                
                try {
                        $dbw = wfGetDB( DB_MASTER );
                        $dbw->begin();
                        
                        // Delete old versions
                        $result = $dbw->select( 'oldimage',
                                array( 'oi_archive_name' ),
                                array( 'oi_name' => $this->name ) );
                        
                        while( $row = $dbw->fetchObject( $result ) ) {
                                $oldName = $row->oi_archive_name;
                                
                                $transaction->add( $this->prepareDeleteOld( $oldName, $reason ) );
                                
                                // We'll need to purge this URL from caches...
                                $urlArr[] = wfImageArchiveUrl( $oldName );
                        }
                        $dbw->freeResult( $result );
                        
                        // And the current version...
                        $transaction->add( $this->prepareDeleteCurrent( $reason ) );
                        
                        $dbw->immediateCommit();
                } catch( MWException $e ) {
                        wfDebug( __METHOD__.": db error, rolling back file transactions\n" );
                        $transaction->rollback();
                        FileStore::unlock();
                        throw $e;
                }
                
                wfDebug( __METHOD__.": deleted db items, applying file transactions\n" );
                $transaction->commit();
                FileStore::unlock();

                
                // Update site_stats
                $site_stats = $dbw->tableName( 'site_stats' );
                $dbw->query( "UPDATE $site_stats SET ss_images=ss_images-1", __METHOD__ );
                
                $this->purgeEverything( $urlArr );
                
                return true;
        }
        
        
        /**
         * Delete an old version of the image.
         *
         * Moves the file into an archive directory (or deletes it)
         * and removes the database row.
         *
         * Cache purging is done; logging is caller's responsibility.
         *
         * @param $reason
         * @throws MWException or FSException on database or filestore failure
         * @return true on success, false on some kind of failure
         */
        function deleteOld( $archiveName, $reason ) {
                $transaction = new FSTransaction();
                $urlArr = array();
                
                if( !FileStore::lock() ) {
                        wfDebug( __METHOD__.": failed to acquire file store lock, aborting\n" );
                        return false;
                }
                
                $transaction = new FSTransaction();
                try {
                        $dbw = wfGetDB( DB_MASTER );
                        $dbw->begin();
                        $transaction->add( $this->prepareDeleteOld( $archiveName, $reason ) );
                        $dbw->immediateCommit();
                } catch( MWException $e ) {
                        wfDebug( __METHOD__.": db error, rolling back file transaction\n" );
                        $transaction->rollback();
                        FileStore::unlock();
                        throw $e;
                }
                
                wfDebug( __METHOD__.": deleted db items, applying file transaction\n" );
                $transaction->commit();
                FileStore::unlock();
                
                $this->purgeDescription();

                // Squid purging
                global $wgUseSquid;
                if ( $wgUseSquid ) {
                        $urlArr = array(
                                wfImageArchiveUrl( $archiveName ),
                        );
                        wfPurgeSquidServers( $urlArr );
                }
                return true;
        }
        
        /**
         * Delete the current version of a file.
         * May throw a database error.
         * @return true on success, false on failure
         */
        private function prepareDeleteCurrent( $reason ) {
                return $this->prepareDeleteVersion(
                        $this->getFullPath(),
                        $reason,
                        'image',
                        array(
                                'fa_name'         => 'img_name',
                                'fa_archive_name' => 'NULL',
                                'fa_size'         => 'img_size',
                                'fa_width'        => 'img_width',
                                'fa_height'       => 'img_height',
                                'fa_metadata'     => 'img_metadata',
                                'fa_bits'         => 'img_bits',
                                'fa_media_type'   => 'img_media_type',
                                'fa_major_mime'   => 'img_major_mime',
                                'fa_minor_mime'   => 'img_minor_mime',
                                'fa_description'  => 'img_description',
                                'fa_user'         => 'img_user',
                                'fa_user_text'    => 'img_user_text',
                                'fa_timestamp'    => 'img_timestamp' ),
                        array( 'img_name' => $this->name ),
                        __METHOD__ );
        }

        /**
         * Delete a given older version of a file.
         * May throw a database error.
         * @return true on success, false on failure
         */
        private function prepareDeleteOld( $archiveName, $reason ) {
                $oldpath = wfImageArchiveDir( $this->name ) .
                        DIRECTORY_SEPARATOR . $archiveName;
                return $this->prepareDeleteVersion(
                        $oldpath,
                        $reason,
                        'oldimage',
                        array(
                                'fa_name'         => 'oi_name',
                                'fa_archive_name' => 'oi_archive_name',
                                'fa_size'         => 'oi_size',
                                'fa_width'        => 'oi_width',
                                'fa_height'       => 'oi_height',
                                'fa_metadata'     => 'NULL',
                                'fa_bits'         => 'oi_bits',
                                'fa_media_type'   => 'NULL',
                                'fa_major_mime'   => 'NULL',
                                'fa_minor_mime'   => 'NULL',
                                'fa_description'  => 'oi_description',
                                'fa_user'         => 'oi_user',
                                'fa_user_text'    => 'oi_user_text',
                                'fa_timestamp'    => 'oi_timestamp' ),
                        array(
                                'oi_name' => $this->name,
                                'oi_archive_name' => $archiveName ),
                        __METHOD__ );
        }

        /**
         * Do the dirty work of backing up an image row and its file
         * (if $wgSaveDeletedFiles is on) and removing the originals.
         *
         * Must be run while the file store is locked and a database
         * transaction is open to avoid race conditions.
         *
         * @return FSTransaction
         */
        private function prepareDeleteVersion( $path, $reason, $table, $fieldMap, $where, $fname ) {
                global $wgUser, $wgSaveDeletedFiles;
                
                // Dupe the file into the file store
                if( file_exists( $path ) ) {
                        if( $wgSaveDeletedFiles ) {
                                $group = 'deleted';
                                
                                $store = FileStore::get( $group );
                                $key = FileStore::calculateKey( $path, $this->extension );
                                $transaction = $store->insert( $key, $path,
                                        FileStore::DELETE_ORIGINAL );
                        } else {
                                $group = null;
                                $key = null;
                                $transaction = FileStore::deleteFile( $path );
                        }
                } else {
                        wfDebug( __METHOD__." deleting already-missing '$path'; moving on to database\n" );
                        $group = null;
                        $key = null;
                        $transaction = new FSTransaction(); // empty
                }
                
                if( $transaction === false ) {
                        // Fail to restore?
                        wfDebug( __METHOD__.": import to file store failed, aborting\n" );
                        throw new MWException( "Could not archive and delete file $path" );
                        return false;
                }
                
                $dbw = wfGetDB( DB_MASTER );
                $storageMap = array(
                        'fa_storage_group' => $dbw->addQuotes( $group ),
                        'fa_storage_key'   => $dbw->addQuotes( $key ),
                        
                        'fa_deleted_user'      => $dbw->addQuotes( $wgUser->getId() ),
                        'fa_deleted_timestamp' => $dbw->timestamp(),
                        'fa_deleted_reason'    => $dbw->addQuotes( $reason ) );
                $allFields = array_merge( $storageMap, $fieldMap );
                
                try {
                        if( $wgSaveDeletedFiles ) {
                                $dbw->insertSelect( 'filearchive', $table, $allFields, $where, $fname );
                        }
                        $dbw->delete( $table, $where, $fname );
                } catch( DBQueryError $e ) {
                        // Something went horribly wrong!
                        // Leave the file as it was...
                        wfDebug( __METHOD__.": database error, rolling back file transaction\n" );
                        $transaction->rollback();
                        throw $e;
                }
                
                return $transaction;
        }
        
        /**
         * Restore all or specified deleted revisions to the given file.
         * Permissions and logging are left to the caller.
         *
         * May throw database exceptions on error.
         *
         * @param $versions set of record ids of deleted items to restore,
         *                    or empty to restore all revisions.
         * @return the number of file revisions restored if successful,
         *         or false on failure
         */
        function restore( $versions=array() ) {
                if( !FileStore::lock() ) {
                        wfDebug( __METHOD__." could not acquire filestore lock\n" );
                        return false;
                }
                
                $transaction = new FSTransaction();
                try {
                        $dbw = wfGetDB( DB_MASTER );
                        $dbw->begin();
                        
                        // Re-confirm whether this image presently exists;
                        // if no we'll need to create an image record for the
                        // first item we restore.
                        $exists = $dbw->selectField( 'image', '1',
                                array( 'img_name' => $this->name ),
                                __METHOD__ );
                        
                        // Fetch all or selected archived revisions for the file,
                        // sorted from the most recent to the oldest.
                        $conditions = array( 'fa_name' => $this->name );
                        if( $versions ) {
                                $conditions['fa_id'] = $versions;
                        }
                        
                        $result = $dbw->select( 'filearchive', '*',
                                $conditions,
                                __METHOD__,
                                array( 'ORDER BY' => 'fa_timestamp DESC' ) );
                        
                        if( $dbw->numRows( $result ) < count( $versions ) ) {
                                // There's some kind of conflict or confusion;
                                // we can't restore everything we were asked to.
                                wfDebug( __METHOD__.": couldn't find requested items\n" );
                                $dbw->rollback();
                                FileStore::unlock();
                                return false;
                        }

                        if( $dbw->numRows( $result ) == 0 ) {
                                // Nothing to do.
                                wfDebug( __METHOD__.": nothing to do\n" );
                                $dbw->rollback();
                                FileStore::unlock();
                                return true;
                        }
                        
                        $revisions = 0;
                        while( $row = $dbw->fetchObject( $result ) ) {
                                $revisions++;
                                $store = FileStore::get( $row->fa_storage_group );
                                if( !$store ) {
                                        wfDebug( __METHOD__.": skipping row with no file.\n" );
                                        continue;
                                }
                                
                                if( $revisions == 1 && !$exists ) {
                                        $destDir = wfImageDir( $row->fa_name );
                                        if ( !is_dir( $destDir ) ) {
                                                wfMkdirParents( $destDir );
                                        }
                                        $destPath = $destDir . DIRECTORY_SEPARATOR . $row->fa_name;
                                        
                                        // We may have to fill in data if this was originally
                                        // an archived file revision.
                                        if( is_null( $row->fa_metadata ) ) {
                                                $tempFile = $store->filePath( $row->fa_storage_key );
                                                $metadata = serialize( $this->retrieveExifData( $tempFile ) );
                                                
                                                $magic = wfGetMimeMagic();
                                                $mime = $magic->guessMimeType( $tempFile, true );
                                                $media_type = $magic->getMediaType( $tempFile, $mime );
                                                list( $major_mime, $minor_mime ) = self::splitMime( $mime );
                                        } else {
                                                $metadata   = $row->fa_metadata;
                                                $major_mime = $row->fa_major_mime;
                                                $minor_mime = $row->fa_minor_mime;
                                                $media_type = $row->fa_media_type;
                                        }
                                        
                                        $table = 'image';
                                        $fields = array(
                                                'img_name'        => $row->fa_name,
                                                'img_size'        => $row->fa_size,
                                                'img_width'       => $row->fa_width,
                                                'img_height'      => $row->fa_height,
                                                'img_metadata'    => $metadata,
                                                'img_bits'        => $row->fa_bits,
                                                'img_media_type'  => $media_type,
                                                'img_major_mime'  => $major_mime,
                                                'img_minor_mime'  => $minor_mime,
                                                'img_description' => $row->fa_description,
                                                'img_user'        => $row->fa_user,
                                                'img_user_text'   => $row->fa_user_text,
                                                'img_timestamp'   => $row->fa_timestamp );
                                } else {
                                        $archiveName = $row->fa_archive_name;
                                        if( $archiveName == '' ) {
                                                // This was originally a current version; we
                                                // have to devise a new archive name for it.
                                                // Format is <timestamp of archiving>!<name>
                                                $archiveName =
                                                        wfTimestamp( TS_MW, $row->fa_deleted_timestamp ) .
                                                        '!' . $row->fa_name;
                                        }
                                        $destDir = wfImageArchiveDir( $row->fa_name );
                                        if ( !is_dir( $destDir ) ) {
                                                wfMkdirParents( $destDir );
                                        }
                                        $destPath = $destDir . DIRECTORY_SEPARATOR . $archiveName;
                                        
                                        $table = 'oldimage';
                                        $fields = array(
                                                'oi_name'         => $row->fa_name,
                                                'oi_archive_name' => $archiveName,
                                                'oi_size'         => $row->fa_size,
                                                'oi_width'        => $row->fa_width,
                                                'oi_height'       => $row->fa_height,
                                                'oi_bits'         => $row->fa_bits,
                                                'oi_description'  => $row->fa_description,
                                                'oi_user'         => $row->fa_user,
                                                'oi_user_text'    => $row->fa_user_text,
                                                'oi_timestamp'    => $row->fa_timestamp );
                                }
                                
                                $dbw->insert( $table, $fields, __METHOD__ );
                                /// @fixme this delete is not totally safe, potentially
                                $dbw->delete( 'filearchive',
                                        array( 'fa_id' => $row->fa_id ),
                                        __METHOD__ );
                                
                                // Check if any other stored revisions use this file;
                                // if so, we shouldn't remove the file from the deletion
                                // archives so they will still work.
                                $useCount = $dbw->selectField( 'filearchive',
                                        'COUNT(*)',
                                        array(
                                                'fa_storage_group' => $row->fa_storage_group,
                                                'fa_storage_key'   => $row->fa_storage_key ),
                                        __METHOD__ );
                                if( $useCount == 0 ) {
                                        wfDebug( __METHOD__.": nothing else using {$row->fa_storage_key}, will deleting after\n" );
                                        $flags = FileStore::DELETE_ORIGINAL;
                                } else {
                                        $flags = 0;
                                }
                                
                                $transaction->add( $store->export( $row->fa_storage_key,
                                        $destPath, $flags ) );
                        }
                        
                        $dbw->immediateCommit();
                } catch( MWException $e ) {
                        wfDebug( __METHOD__." caught error, aborting\n" );
                        $transaction->rollback();
                        throw $e;
                }
                
                $transaction->commit();
                FileStore::unlock();
                
                if( $revisions > 0 ) {
                        if( !$exists ) {
                                wfDebug( __METHOD__." restored $revisions items, creating a new current\n" );
                                
                                // Update site_stats
                                $site_stats = $dbw->tableName( 'site_stats' );
                                $dbw->query( "UPDATE $site_stats SET ss_images=ss_images+1", __METHOD__ );
                                
                                $this->purgeEverything();
                        } else {
                                wfDebug( __METHOD__." restored $revisions as archived versions\n" );
                                $this->purgeDescription();
                        }
                }
                
                return $revisions;
        }
        
} //class

/**
 * Wrapper class for thumbnail images
 * @package MediaWiki
 */
class ThumbnailImage {
        /**
         * @param string $path Filesystem path to the thumb
         * @param string $url URL path to the thumb
         * @private
         */
        function ThumbnailImage( $url, $width, $height, $path = false ) {
                $this->url = $url;
                $this->width = round( $width );
                $this->height = round( $height );
                        # These should be integers when they get here.
                        # If not, there's a bug somewhere.  But let's at
                        # least produce valid HTML code regardless.
                $this->path = $path;
        }

        /**
         * @return string The thumbnail URL
         */
        function getUrl() {
                return $this->url;
        }

        /**
         * Return HTML <img ... /> tag for the thumbnail, will include
         * width and height attributes and a blank alt text (as required).
         *
         * You can set or override additional attributes by passing an
         * associative array of name => data pairs. The data will be escaped
         * for HTML output, so should be in plaintext.
         *
         * @param array $attribs
         * @return string
         * @public
         */
        function toHtml( $attribs = array() ) {
                $attribs['src'] = $this->url;
                $attribs['width'] = $this->width;
                $attribs['height'] = $this->height;
                if( !isset( $attribs['alt'] ) ) $attribs['alt'] = '';

                $html = '<img ';
                foreach( $attribs as $name => $data ) {
                        $html .= $name . '="' . htmlspecialchars( $data ) . '" ';
                }
                $html .= '/>';
                return $html;
        }

}

?>