1 files changed, 313 insertions, 0 deletions
diff --git a/includes/media/SVGMetadataExtractor.php b/includes/media/SVGMetadataExtractor.php
new file mode 100644
index 00000000..66ae1edf
--- /dev/null
+++ b/includes/media/SVGMetadataExtractor.php
@@ -0,0 +1,313 @@
+<?php
+/**
+ * SVGMetadataExtractor.php
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Media
+ * @author Derk-Jan Hartman <hartman _at_ videolan d0t org>
+ * @author Brion Vibber
+ * @copyright Copyright © 2010-2010 Brion Vibber, Derk-Jan Hartman
+ * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
+ */
+
+class SVGMetadataExtractor {
+	static function getMetadata( $filename ) {
+		$svg = new SVGReader( $filename );
+		return $svg->getMetadata();
+	}
+}
+
+class SVGReader {
+	const DEFAULT_WIDTH = 512;
+	const DEFAULT_HEIGHT = 512;
+	const NS_SVG = 'http://www.w3.org/2000/svg';
+
+	private $reader = null;
+	private $mDebug = false;
+	private $metadata = Array();
+
+	/**
+	 * Constructor
+	 *
+	 * Creates an SVGReader drawing from the source provided
+	 * @param $source String: URI from which to read
+	 */
+	function __construct( $source ) {
+		global $wgSVGMetadataCutoff;
+		$this->reader = new XMLReader();
+
+		// Don't use $file->getSize() since file object passed to SVGHandler::getMetadata is bogus.
+		$size = filesize( $source );
+		if ( $size === false ) {
+			throw new MWException( "Error getting filesize of SVG." );
+		} 
+
+		if ( $size > $wgSVGMetadataCutoff ) {
+			$this->debug( "SVG is $size bytes, which is bigger than $wgSVGMetadataCutoff. Truncating." );
+			$contents = file_get_contents( $source, false, null, -1, $wgSVGMetadataCutoff );
+			if ($contents === false) {
+				throw new MWException( 'Error reading SVG file.' );
+			}
+			$this->reader->XML( $contents, null, LIBXML_NOERROR | LIBXML_NOWARNING );
+		} else {
+			$this->reader->open( $source, null, LIBXML_NOERROR | LIBXML_NOWARNING );
+		}
+
+		$this->metadata['width'] = self::DEFAULT_WIDTH;
+		$this->metadata['height'] = self::DEFAULT_HEIGHT;
+
+		// Because we cut off the end of the svg making an invalid one. Complicated
+		// try catch thing to make sure warnings get restored. Seems like there should
+		// be a better way.
+		wfSuppressWarnings();
+		try {
+			$this->read();
+		} catch( Exception $e ) {
+			wfRestoreWarnings();
+			throw $e;
+		}
+		wfRestoreWarnings();
+	}
+
+	/*
+	 * @return Array with the known metadata
+	 */
+	public function getMetadata() {
+		return $this->metadata;
+	}
+
+	/*
+	 * Read the SVG
+	 */
+	public function read() {
+		$keepReading = $this->reader->read();
+
+		/* Skip until first element */
+		while( $keepReading && $this->reader->nodeType != XmlReader::ELEMENT ) {
+			$keepReading = $this->reader->read();
+		}
+
+		if ( $this->reader->localName != 'svg' || $this->reader->namespaceURI != self::NS_SVG ) {
+			throw new MWException( "Expected <svg> tag, got ".
+				$this->reader->localName . " in NS " . $this->reader->namespaceURI );
+		}
+		$this->debug( "<svg> tag is correct." );
+		$this->handleSVGAttribs();
+
+		$exitDepth =  $this->reader->depth;
+		$keepReading = $this->reader->read();
+		while ( $keepReading ) {
+			$tag = $this->reader->localName;
+			$type = $this->reader->nodeType;
+			$isSVG = ($this->reader->namespaceURI == self::NS_SVG);
+
+			$this->debug( "$tag" );
+
+			if ( $isSVG && $tag == 'svg' && $type == XmlReader::END_ELEMENT && $this->reader->depth <= $exitDepth ) {
+				break;
+			} elseif ( $isSVG && $tag == 'title' ) {
+				$this->readField( $tag, 'title' );
+			} elseif ( $isSVG && $tag == 'desc' ) {
+				$this->readField( $tag, 'description' );
+			} elseif ( $isSVG && $tag == 'metadata' && $type == XmlReader::ELEMENT ) {
+				$this->readXml( $tag, 'metadata' );
+			} elseif ( $tag !== '#text' ) {
+				$this->debug( "Unhandled top-level XML tag $tag" );
+
+				if ( !isset( $this->metadata['animated'] ) ) {
+					// Recurse into children of current tag, looking for animation.
+					$this->animateFilter( $tag );
+				}
+			}
+
+			// Goto next element, which is sibling of current (Skip children).
+			$keepReading = $this->reader->next();
+		}
+
+		return true;
+	}
+
+	/*
+	 * Read a textelement from an element
+	 *
+	 * @param String $name of the element that we are reading from
+	 * @param String $metafield that we will fill with the result
+	 */
+	private function readField( $name, $metafield=null ) {
+		$this->debug ( "Read field $metafield" );
+		if( !$metafield || $this->reader->nodeType != XmlReader::ELEMENT ) {
+			return;
+		}
+		$keepReading = $this->reader->read();
+		while( $keepReading ) {
+			if( $this->reader->localName == $name && $this->namespaceURI == self::NS_SVG && $this->reader->nodeType == XmlReader::END_ELEMENT ) {
+				break;
+			} elseif( $this->reader->nodeType == XmlReader::TEXT ){
+				$this->metadata[$metafield] = trim( $this->reader->value );
+			}
+			$keepReading = $this->reader->read();
+		}
+	}
+
+	/*
+	 * Read an XML snippet from an element
+	 *
+	 * @param String $metafield that we will fill with the result
+	 */
+	private function readXml( $metafield=null ) {
+		$this->debug ( "Read top level metadata" );
+		if( !$metafield || $this->reader->nodeType != XmlReader::ELEMENT ) {
+			return;
+		}
+		// TODO: find and store type of xml snippet. metadata['metadataType'] = "rdf"
+		$this->metadata[$metafield] = trim( $this->reader->readInnerXML() );
+		$this->reader->next();
+	}
+
+	/*
+	 * Filter all children, looking for animate elements
+	 *
+	 * @param String $name of the element that we are reading from
+	 */
+	private function animateFilter( $name ) {
+		$this->debug ( "animate filter" );
+		if( $this->reader->nodeType != XmlReader::ELEMENT ) {
+			return;
+		}
+		$exitDepth =  $this->reader->depth;
+		$keepReading = $this->reader->read();
+		while( $keepReading ) {
+			if( $this->reader->localName == $name && $this->reader->depth <= $exitDepth
+				&& $this->reader->nodeType == XmlReader::END_ELEMENT ) {
+				break;
+			} elseif ( $this->reader->namespaceURI == self::NS_SVG && $this->reader->nodeType == XmlReader::ELEMENT ) {
+				switch( $this->reader->localName ) {
+					case 'animate':
+					case 'set':
+					case 'animateMotion':
+					case 'animateColor':
+					case 'animateTransform':
+						$this->debug( "HOUSTON WE HAVE ANIMATION" );
+						$this->metadata['animated'] = true;
+						break;
+				}
+			}
+			$keepReading = $this->reader->read();
+		}
+	}
+
+	private function throwXmlError( $err ) {
+		$this->debug( "FAILURE: $err" );
+		wfDebug( "SVGReader XML error: $err\n" );
+	}
+
+	private function debug( $data ) {
+		if( $this->mDebug ) {
+			wfDebug( "SVGReader: $data\n" );
+		}
+	}
+
+	private function warn( $data ) {
+		wfDebug( "SVGReader: $data\n" );
+	}
+
+	private function notice( $data ) {
+		wfDebug( "SVGReader WARN: $data\n" );
+	}
+
+	/*
+	 * Parse the attributes of an SVG element
+	 *
+	 * The parser has to be in the start element of <svg>
+	 */
+	private function handleSVGAttribs( ) {
+		$defaultWidth = self::DEFAULT_WIDTH;
+		$defaultHeight = self::DEFAULT_HEIGHT;
+		$aspect = 1.0;
+		$width = null;
+		$height = null;
+
+		if( $this->reader->getAttribute('viewBox') ) {
+			// min-x min-y width height
+			$viewBox = preg_split( '/\s+/', trim( $this->reader->getAttribute('viewBox') ) );
+			if( count( $viewBox ) == 4 ) {
+				$viewWidth = $this->scaleSVGUnit( $viewBox[2] );
+				$viewHeight = $this->scaleSVGUnit( $viewBox[3] );
+				if( $viewWidth > 0 && $viewHeight > 0 ) {
+					$aspect = $viewWidth / $viewHeight;
+					$defaultHeight = $defaultWidth / $aspect;
+				}
+			}
+		}
+		if( $this->reader->getAttribute('width') ) {
+			$width = $this->scaleSVGUnit( $this->reader->getAttribute('width'), $defaultWidth );
+		}
+		if( $this->reader->getAttribute('height') ) {
+			$height = $this->scaleSVGUnit( $this->reader->getAttribute('height'), $defaultHeight );
+		}
+
+		if( !isset( $width ) && !isset( $height ) ) {
+			$width = $defaultWidth;
+			$height = $width / $aspect;
+		} elseif( isset( $width ) && !isset( $height ) ) {
+			$height = $width / $aspect;
+		} elseif( isset( $height ) && !isset( $width ) ) {
+			$width = $height * $aspect;
+		}
+
+		if( $width > 0 && $height > 0 ) {
+			$this->metadata['width'] = intval( round( $width ) );
+			$this->metadata['height'] = intval( round( $height ) );
+		}
+	}
+
+	/**
+	 * Return a rounded pixel equivalent for a labeled CSS/SVG length.
+	 * http://www.w3.org/TR/SVG11/coords.html#UnitIdentifiers
+	 *
+	 * @param $length String: CSS/SVG length.
+	 * @param $viewportSize: Float optional scale for percentage units...
+	 * @return float: length in pixels
+	 */
+	static function scaleSVGUnit( $length, $viewportSize=512 ) {
+		static $unitLength = array(
+			'px' => 1.0,
+			'pt' => 1.25,
+			'pc' => 15.0,
+			'mm' => 3.543307,
+			'cm' => 35.43307,
+			'in' => 90.0,
+			'em' => 16.0, // fake it?
+			'ex' => 12.0, // fake it?
+			''   => 1.0, // "User units" pixels by default
+			);
+		$matches = array();
+		if( preg_match( '/^\s*(\d+(?:\.\d+)?)(em|ex|px|pt|pc|cm|mm|in|%|)\s*$/', $length, $matches ) ) {
+			$length = floatval( $matches[1] );
+			$unit = $matches[2];
+			if( $unit == '%' ) {
+				return $length * 0.01 * $viewportSize;
+			} else {
+				return $length * $unitLength[$unit];
+			}
+		} else {
+			// Assume pixels
+			return floatval( $length );
+		}
+	}
+}