* Reduced some pointless regex capture overhead

[mediawiki.git] / includes / media / Generic.php

<?php
/**
 * Media-handling base classes and generic functionality
 *
 * @file
 * @ingroup Media
 */

/**
 * Base media handler class
 *
 * @ingroup Media
 */
abstract class MediaHandler {
        const TRANSFORM_LATER = 1;

        /**
         * Instance cache
         */
        static $handlers = array();

        /**
         * Get a MediaHandler for a given MIME type from the instance cache
         */
        static function getHandler( $type ) {
                global $wgMediaHandlers;
                if ( !isset( $wgMediaHandlers[$type] ) ) {
                        wfDebug( __METHOD__ . ": no handler found for $type.\n");
                        return false;
                }
                $class = $wgMediaHandlers[$type];
                if ( !isset( self::$handlers[$class] ) ) {
                        self::$handlers[$class] = new $class;
                        if ( !self::$handlers[$class]->isEnabled() ) {
                                self::$handlers[$class] = false;
                        }
                }
                return self::$handlers[$class];
        }

        /**
         * Get an associative array mapping magic word IDs to parameter names.
         * Will be used by the parser to identify parameters.
         */
        abstract function getParamMap();

        /*
         * Validate a thumbnail parameter at parse time.
         * Return true to accept the parameter, and false to reject it.
         * If you return false, the parser will do something quiet and forgiving.
         */
        abstract function validateParam( $name, $value );

        /**
         * Merge a parameter array into a string appropriate for inclusion in filenames
         */
        abstract function makeParamString( $params );

        /**
         * Parse a param string made with makeParamString back into an array
         */
        abstract function parseParamString( $str );

        /**
         * Changes the parameter array as necessary, ready for transformation.
         * Should be idempotent.
         * Returns false if the parameters are unacceptable and the transform should fail
         */
        abstract function normaliseParams( $image, &$params );

        /**
         * Get an image size array like that returned by getimagesize(), or false if it
         * can't be determined.
         *
         * @param $image File: the image object, or false if there isn't one
         * @param $path String: the filename
         * @return Array
         */
        abstract function getImageSize( $image, $path );

        /**
         * Get handler-specific metadata which will be saved in the img_metadata field.
         *
         * @param $image File: the image object, or false if there isn't one
         * @param $path String: the filename
         * @return String
         */
        function getMetadata( $image, $path ) { return ''; }

        /**
         * Get a string describing the type of metadata, for display purposes.
         */
        function getMetadataType( $image ) { return false; }

        /**
         * Check if the metadata string is valid for this handler.
         * If it returns false, Image will reload the metadata from the file and update the database
         */
        function isMetadataValid( $image, $metadata ) { return true; }


        /**
         * Get a MediaTransformOutput object representing an alternate of the transformed
         * output which will call an intermediary thumbnail assist script.
         *
         * Used when the repository has a thumbnailScriptUrl option configured.
         *
         * Return false to fall back to the regular getTransform().
         */
        function getScriptedTransform( $image, $script, $params ) {
                return false;
        }

        /**
         * Get a MediaTransformOutput object representing the transformed output. Does not
         * actually do the transform.
         *
         * @param $image File: the image object
         * @param $dstPath String: filesystem destination path
         * @param $dstUrl String: Destination URL to use in output HTML
         * @param $params Array: Arbitrary set of parameters validated by $this->validateParam()
         */
        function getTransform( $image, $dstPath, $dstUrl, $params ) {
                return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
        }

        /**
         * Get a MediaTransformOutput object representing the transformed output. Does the
         * transform unless $flags contains self::TRANSFORM_LATER.
         *
         * @param $image File: the image object
         * @param $dstPath String: filesystem destination path
         * @param $dstUrl String: destination URL to use in output HTML
         * @param $params Array: arbitrary set of parameters validated by $this->validateParam()
         * @param $flags Integer: a bitfield, may contain self::TRANSFORM_LATER
         */
        abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );

        /**
         * Get the thumbnail extension and MIME type for a given source MIME type
         * @return array thumbnail extension and MIME type
         */
        function getThumbType( $ext, $mime, $params = null ) {
                return array( $ext, $mime );
        }

        /**
         * True if the handled types can be transformed
         */
        function canRender( $file ) { return true; }
        /**
         * True if handled types cannot be displayed directly in a browser
         * but can be rendered
         */
        function mustRender( $file ) { return false; }
        /**
         * True if the type has multi-page capabilities
         */
        function isMultiPage( $file ) { return false; }
        /**
         * Page count for a multi-page document, false if unsupported or unknown
         */
        function pageCount( $file ) { return false; }
        /**
         * The material is vectorized and thus scaling is lossless
         */
        function isVectorized( $file ) { return false; }
        /**
         * False if the handler is disabled for all files
         */
        function isEnabled() { return true; }

        /**
         * Get an associative array of page dimensions
         * Currently "width" and "height" are understood, but this might be
         * expanded in the future.
         * Returns false if unknown or if the document is not multi-page.
         */
        function getPageDimensions( $image, $page ) {
                $gis = $this->getImageSize( $image, $image->getPath() );
                return array(
                        'width' => $gis[0],
                        'height' => $gis[1]
                );
        }

        /**
         * Generic getter for text layer.
         * Currently overloaded by PDF and DjVu handlers
         */
        function getPageText( $image, $page ) {
                return false;
        }

        /**
         * Get an array structure that looks like this:
         *
         * array(
         *    'visible' => array(
         *       'Human-readable name' => 'Human readable value',
         *       ...
         *    ),
         *    'collapsed' => array(
         *       'Human-readable name' => 'Human readable value',
         *       ...
         *    )
         * )
         * The UI will format this into a table where the visible fields are always
         * visible, and the collapsed fields are optionally visible.
         *
         * The function should return false if there is no metadata to display.
         */

        /**
         * FIXME: I don't really like this interface, it's not very flexible
         * I think the media handler should generate HTML instead. It can do
         * all the formatting according to some standard. That makes it possible
         * to do things like visual indication of grouped and chained streams
         * in ogg container files.
         */
        function formatMetadata( $image ) {
                return false;
        }

        /**
         * @todo Fixme: document this!
         * 'value' thingy goes into a wikitext table; it used to be escaped but
         * that was incompatible with previous practice of customized display
         * with wikitext formatting via messages such as 'exif-model-value'.
         * So the escaping is taken back out, but generally this seems a confusing
         * interface.
         */
        protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
                $array[$visibility][] = array(
                        'id' => "$type-$id",
                        'name' => wfMsg( "$type-$id", $param ),
                        'value' => $value
                );
        }

        function getShortDesc( $file ) {
                global $wgLang;
                $nbytes = '(' . wfMsgExt( 'nbytes', array( 'parsemag', 'escape' ),
                        $wgLang->formatNum( $file->getSize() ) ) . ')';
                return "$nbytes";
        }

        function getLongDesc( $file ) {
                global $wgUser;
                $sk = $wgUser->getSkin();
                return wfMsgExt( 'file-info', 'parseinline',
                        $sk->formatSize( $file->getSize() ),
                        $file->getMimeType() );
        }
        
        static function getGeneralShortDesc( $file ) {
                global $wgLang;
                $nbytes = '(' . wfMsgExt( 'nbytes', array( 'parsemag', 'escape' ),
                        $wgLang->formatNum( $file->getSize() ) ) . ')';
                return "$nbytes";
        }

        static function getGeneralLongDesc( $file ) {
                global $wgUser;
                $sk = $wgUser->getSkin();
                return wfMsgExt( 'file-info', 'parseinline',
                        $sk->formatSize( $file->getSize() ),
                        $file->getMimeType() );
        }

        function getDimensionsString( $file ) {
                return '';
        }

        /**
         * Modify the parser object post-transform
         */
        function parserTransformHook( $parser, $file ) {}

        /**
         * File validation hook called on upload.
         *
         * If the file at the given local path is not valid, or its MIME type does not 
         * match the handler class, a Status object should be returned containing
         * relevant errors.
         * 
         * @param $fileName The local path to the file.
         * @return Status object
         */
        function verifyUpload( $fileName ) {
                return Status::newGood();
        }

        /**
         * Check for zero-sized thumbnails. These can be generated when
         * no disk space is available or some other error occurs
         *
         * @param $dstPath The location of the suspect file
         * @param $retval Return value of some shell process, file will be deleted if this is non-zero
         * @return true if removed, false otherwise
         */
        function removeBadFile( $dstPath, $retval = 0 ) {
                if( file_exists( $dstPath ) ) {
                        $thumbstat = stat( $dstPath );
                        if( $thumbstat['size'] == 0 || $retval != 0 ) {
                                wfDebugLog( 'thumbnail',
                                        sprintf( 'Removing bad %d-byte thumbnail "%s"',
                                                $thumbstat['size'], $dstPath ) );
                                unlink( $dstPath );
                                return true;
                        }
                }
                return false;
        }
}

/**
 * Media handler abstract base class for images
 *
 * @ingroup Media
 */
abstract class ImageHandler extends MediaHandler {
        function canRender( $file ) {
                if ( $file->getWidth() && $file->getHeight() ) {
                        return true;
                } else {
                        return false;
                }
        }

        function getParamMap() {
                return array( 'img_width' => 'width' );
        }

        function validateParam( $name, $value ) {
                if ( in_array( $name, array( 'width', 'height' ) ) ) {
                        if ( $value <= 0 ) {
                                return false;
                        } else {
                                return true;
                        }
                } else {
                        return false;
                }
        }

        function makeParamString( $params ) {
                if ( isset( $params['physicalWidth'] ) ) {
                        $width = $params['physicalWidth'];
                } elseif ( isset( $params['width'] ) ) {
                        $width = $params['width'];
                } else {
                        throw new MWException( 'No width specified to '.__METHOD__ );
                }
                # Removed for ProofreadPage
                #$width = intval( $width );
                return "{$width}px";
        }

        function parseParamString( $str ) {
                $m = false;
                if ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
                        return array( 'width' => $m[1] );
                } else {
                        return false;
                }
        }

        function getScriptParams( $params ) {
                return array( 'width' => $params['width'] );
        }

        function normaliseParams( $image, &$params ) {
                $mimeType = $image->getMimeType();

                if ( !isset( $params['width'] ) ) {
                        return false;
                }

                if ( !isset( $params['page'] ) ) {
                        $params['page'] = 1;
                } else  {
                        if ( $params['page'] > $image->pageCount() ) {
                                $params['page'] = $image->pageCount();
                        }

                        if ( $params['page'] < 1 ) {
                                $params['page'] = 1;
                        }
                }

                $srcWidth = $image->getWidth( $params['page'] );
                $srcHeight = $image->getHeight( $params['page'] );
                if ( isset( $params['height'] ) && $params['height'] != -1 ) {
                        if ( $params['width'] * $srcHeight > $params['height'] * $srcWidth ) {
                                $params['width'] = wfFitBoxWidth( $srcWidth, $srcHeight, $params['height'] );
                        }
                }
                $params['height'] = File::scaleHeight( $srcWidth, $srcHeight, $params['width'] );
                if ( !$this->validateThumbParams( $params['width'], $params['height'], $srcWidth, $srcHeight, $mimeType ) ) {
                        return false;
                }
                return true;
        }

        /**
         * Get a transform output object without actually doing the transform
         */
        function getTransform( $image, $dstPath, $dstUrl, $params ) {
                return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
        }

        /**
         * Validate thumbnail parameters and fill in the correct height
         *
         * @param $width Integer: specified width (input/output)
         * @param $height Integer: height (output only)
         * @param $srcWidth Integer: width of the source image
         * @param $srcHeight Integer: height of the source image
         * @param $mimeType Unused
         * @return false to indicate that an error should be returned to the user.
         */
        function validateThumbParams( &$width, &$height, $srcWidth, $srcHeight, $mimeType ) {
                $width = intval( $width );

                # Sanity check $width
                if( $width <= 0) {
                        wfDebug( __METHOD__.": Invalid destination width: $width\n" );
                        return false;
                }
                if ( $srcWidth <= 0 ) {
                        wfDebug( __METHOD__.": Invalid source width: $srcWidth\n" );
                        return false;
                }

                $height = File::scaleHeight( $srcWidth, $srcHeight, $width );
                return true;
        }

        function getScriptedTransform( $image, $script, $params ) {
                if ( !$this->normaliseParams( $image, $params ) ) {
                        return false;
                }
                $url = $script . '&' . wfArrayToCGI( $this->getScriptParams( $params ) );
                $page = isset( $params['page'] ) ? $params['page'] : false;

                if( $image->mustRender() || $params['width'] < $image->getWidth() ) {
                        return new ThumbnailImage( $image, $url, $params['width'], $params['height'], $page );
                }
        }

        function getImageSize( $image, $path ) {
                wfSuppressWarnings();
                $gis = getimagesize( $path );
                wfRestoreWarnings();
                return $gis;
        }

        function isAnimatedImage( $image ) {
                return false;
        }

        function getShortDesc( $file ) {
                global $wgLang;
                $nbytes = wfMsgExt( 'nbytes', array( 'parsemag', 'escape' ),
                        $wgLang->formatNum( $file->getSize() ) );
                $widthheight = wfMsgHtml( 'widthheight', $wgLang->formatNum( $file->getWidth() ) ,$wgLang->formatNum( $file->getHeight() ) );

                return "$widthheight ($nbytes)";
        }

        function getLongDesc( $file ) {
                global $wgLang;
                return wfMsgExt('file-info-size', 'parseinline',
                        $wgLang->formatNum( $file->getWidth() ),
                        $wgLang->formatNum( $file->getHeight() ),
                        $wgLang->formatSize( $file->getSize() ),
                        $file->getMimeType() );
        }

        function getDimensionsString( $file ) {
                global $wgLang;
                $pages = $file->pageCount();
                $width = $wgLang->formatNum( $file->getWidth() );
                $height = $wgLang->formatNum( $file->getHeight() );
                $pagesFmt = $wgLang->formatNum( $pages );

                if ( $pages > 1 ) {
                        return wfMsgExt( 'widthheightpage', 'parsemag', $width, $height, $pagesFmt );
                } else {
                        return wfMsg( 'widthheight', $width, $height );
                }
        }
}