Split SVGReader to its own file
authorReedy <reedy@wikimedia.org>
Sun, 14 Apr 2019 00:07:50 +0000 (01:07 +0100)
committerReedy <reedy@wikimedia.org>
Sun, 14 Apr 2019 00:29:52 +0000 (00:29 +0000)
Change-Id: I9fc442225a37c14d0606508aed5ef496a5ad82ba

.phpcs.xml
autoload.php
includes/media/SVGMetadataExtractor.php
includes/media/SVGReader.php [new file with mode: 0644]

index 6b625e5..5f9d078 100644 (file)
                <exclude-pattern>*/includes/libs/filebackend/SwiftFileBackend\.php</exclude-pattern>
                <exclude-pattern>*/includes/logging/LogEntry\.php</exclude-pattern>
                <exclude-pattern>*/includes/logging/LogFormatter\.php</exclude-pattern>
-               <exclude-pattern>*/includes/media/SVGMetadataExtractor\.php</exclude-pattern>
                <exclude-pattern>*/includes/parser/Preprocessor_DOM\.php</exclude-pattern>
                <exclude-pattern>*/includes/parser/Preprocessor_Hash\.php</exclude-pattern>
                <exclude-pattern>*/includes/parser/Preprocessor\.php</exclude-pattern>
index 38ad652..1bd32a7 100644 (file)
@@ -1291,7 +1291,7 @@ $wgAutoloadLocalClasses = [
        'RunJobs' => __DIR__ . '/maintenance/runJobs.php',
        'RunnableJob' => __DIR__ . '/includes/jobqueue/RunnableJob.php',
        'SVGMetadataExtractor' => __DIR__ . '/includes/media/SVGMetadataExtractor.php',
-       'SVGReader' => __DIR__ . '/includes/media/SVGMetadataExtractor.php',
+       'SVGReader' => __DIR__ . '/includes/media/SVGReader.php',
        'SamplingStatsdClient' => __DIR__ . '/includes/libs/stats/SamplingStatsdClient.php',
        'Sanitizer' => __DIR__ . '/includes/parser/Sanitizer.php',
        'ScopedLock' => __DIR__ . '/includes/libs/lockmanager/ScopedLock.php',
index bc5eb09..ac332b7 100644 (file)
@@ -35,361 +35,3 @@ class SVGMetadataExtractor {
                return $svg->getMetadata();
        }
 }
-
-/**
- * @ingroup Media
- */
-class SVGReader {
-       const DEFAULT_WIDTH = 512;
-       const DEFAULT_HEIGHT = 512;
-       const NS_SVG = 'http://www.w3.org/2000/svg';
-       const LANG_PREFIX_MATCH = 1;
-       const LANG_FULL_MATCH = 2;
-
-       /** @var null|XMLReader */
-       private $reader = null;
-
-       /** @var bool */
-       private $mDebug = false;
-
-       /** @var array */
-       private $metadata = [];
-       private $languages = [];
-       private $languagePrefixes = [];
-
-       /**
-        * Creates an SVGReader drawing from the source provided
-        * @param string $source URI from which to read
-        * @throws MWException|Exception
-        */
-       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, 0, $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 );
-               }
-
-               // Expand entities, since Adobe Illustrator uses them for xmlns
-               // attributes (T33719). Note that libxml2 has some protection
-               // against large recursive entity expansions so this is not as
-               // insecure as it might appear to be. However, it is still extremely
-               // insecure. It's necessary to wrap any read() calls with
-               // libxml_disable_entity_loader() to avoid arbitrary local file
-               // inclusion, or even arbitrary code execution if the expect
-               // extension is installed (T48859).
-               $oldDisable = libxml_disable_entity_loader( true );
-               $this->reader->setParserProperty( XMLReader::SUBST_ENTITIES, true );
-
-               $this->metadata['width'] = self::DEFAULT_WIDTH;
-               $this->metadata['height'] = self::DEFAULT_HEIGHT;
-
-               // The size in the units specified by the SVG file
-               // (for the metadata box)
-               // Per the SVG spec, if unspecified, default to '100%'
-               $this->metadata['originalWidth'] = '100%';
-               $this->metadata['originalHeight'] = '100%';
-
-               // 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.
-               Wikimedia\suppressWarnings();
-               try {
-                       $this->read();
-               } catch ( Exception $e ) {
-                       // Note, if this happens, the width/height will be taken to be 0x0.
-                       // Should we consider it the default 512x512 instead?
-                       Wikimedia\restoreWarnings();
-                       libxml_disable_entity_loader( $oldDisable );
-                       throw $e;
-               }
-               Wikimedia\restoreWarnings();
-               libxml_disable_entity_loader( $oldDisable );
-       }
-
-       /**
-        * @return array Array with the known metadata
-        */
-       public function getMetadata() {
-               return $this->metadata;
-       }
-
-       /**
-        * Read the SVG
-        * @throws MWException
-        * @return bool
-        */
-       protected 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( 'metadata' );
-                       } elseif ( $isSVG && $tag == 'script' ) {
-                               // We normally do not allow scripted svgs.
-                               // However its possible to configure MW to let them
-                               // in, and such files should be considered animated.
-                               $this->metadata['animated'] = true;
-                       } elseif ( $tag !== '#text' ) {
-                               $this->debug( "Unhandled top-level XML tag $tag" );
-
-                               // Recurse into children of current tag, looking for animation and languages.
-                               $this->animateFilterAndLang( $tag );
-                       }
-
-                       // Goto next element, which is sibling of current (Skip children).
-                       $keepReading = $this->reader->next();
-               }
-
-               $this->reader->close();
-
-               $this->metadata['translations'] = $this->languages + $this->languagePrefixes;
-
-               return true;
-       }
-
-       /**
-        * Read a textelement from an element
-        *
-        * @param string $name Name of the element that we are reading from
-        * @param string $metafield Field 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->reader->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 Field that we will fill with the result
-        * @throws MWException
-        */
-       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 animated elements.
-        * Also get a list of languages that can be targeted.
-        *
-        * @param string $name Name of the element that we are reading from
-        */
-       private function animateFilterAndLang( $name ) {
-               $this->debug( "animate filter for tag $name" );
-               if ( $this->reader->nodeType != XMLReader::ELEMENT ) {
-                       return;
-               }
-               if ( $this->reader->isEmptyElement ) {
-                       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
-                       ) {
-                               $sysLang = $this->reader->getAttribute( 'systemLanguage' );
-                               if ( !is_null( $sysLang ) && $sysLang !== '' ) {
-                                       // See https://www.w3.org/TR/SVG/struct.html#SystemLanguageAttribute
-                                       $langList = explode( ',', $sysLang );
-                                       foreach ( $langList as $langItem ) {
-                                               $langItem = trim( $langItem );
-                                               if ( Language::isWellFormedLanguageTag( $langItem ) ) {
-                                                       $this->languages[$langItem] = self::LANG_FULL_MATCH;
-                                               }
-                                               // Note, the standard says that any prefix should work,
-                                               // here we do only the initial prefix, since that will catch
-                                               // 99% of cases, and we are going to compare against fallbacks.
-                                               // This differs mildly from how the spec says languages should be
-                                               // handled, however it matches better how the MediaWiki language
-                                               // preference is generally handled.
-                                               $dash = strpos( $langItem, '-' );
-                                               // Intentionally checking both !false and > 0 at the same time.
-                                               if ( $dash ) {
-                                                       $itemPrefix = substr( $langItem, 0, $dash );
-                                                       if ( Language::isWellFormedLanguageTag( $itemPrefix ) ) {
-                                                               $this->languagePrefixes[$itemPrefix] = self::LANG_PREFIX_MATCH;
-                                                       }
-                                               }
-                                       }
-                               }
-                               switch ( $this->reader->localName ) {
-                                       case 'script':
-                                               // Normally we disallow files with
-                                               // <script>, but its possible
-                                               // to configure MW to disable
-                                               // such checks.
-                                       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 debug( $data ) {
-               if ( $this->mDebug ) {
-                       wfDebug( "SVGReader: $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*[\s,]\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 );
-                       $this->metadata['originalWidth'] = $this->reader->getAttribute( 'width' );
-               }
-               if ( $this->reader->getAttribute( 'height' ) ) {
-                       $height = $this->scaleSVGUnit( $this->reader->getAttribute( 'height' ), $defaultHeight );
-                       $this->metadata['originalHeight'] = $this->reader->getAttribute( 'height' );
-               }
-
-               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.
-        * https://www.w3.org/TR/SVG11/coords.html#Units
-        *
-        * @param string $length CSS/SVG length.
-        * @param float|int $viewportSize Optional scale for percentage units...
-        * @return float Length in pixels
-        */
-       static function scaleSVGUnit( $length, $viewportSize = 512 ) {
-               static $unitLength = [
-                       '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
-               ];
-               $matches = [];
-               if ( preg_match(
-                       '/^\s*([-+]?\d*(?:\.\d+|\d+)(?:[Ee][-+]?\d+)?)\s*(em|ex|px|pt|pc|cm|mm|in|%|)\s*$/',
-                       $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 );
-               }
-       }
-}
diff --git a/includes/media/SVGReader.php b/includes/media/SVGReader.php
new file mode 100644 (file)
index 0000000..480aec5
--- /dev/null
@@ -0,0 +1,384 @@
+<?php
+/**
+ * Extraction of SVG image metadata.
+ *
+ * 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 GPL-2.0-or-later
+ */
+
+/**
+ * @ingroup Media
+ */
+class SVGReader {
+       const DEFAULT_WIDTH = 512;
+       const DEFAULT_HEIGHT = 512;
+       const NS_SVG = 'http://www.w3.org/2000/svg';
+       const LANG_PREFIX_MATCH = 1;
+       const LANG_FULL_MATCH = 2;
+
+       /** @var null|XMLReader */
+       private $reader = null;
+
+       /** @var bool */
+       private $mDebug = false;
+
+       /** @var array */
+       private $metadata = [];
+       private $languages = [];
+       private $languagePrefixes = [];
+
+       /**
+        * Creates an SVGReader drawing from the source provided
+        * @param string $source URI from which to read
+        * @throws MWException|Exception
+        */
+       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, 0, $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 );
+               }
+
+               // Expand entities, since Adobe Illustrator uses them for xmlns
+               // attributes (T33719). Note that libxml2 has some protection
+               // against large recursive entity expansions so this is not as
+               // insecure as it might appear to be. However, it is still extremely
+               // insecure. It's necessary to wrap any read() calls with
+               // libxml_disable_entity_loader() to avoid arbitrary local file
+               // inclusion, or even arbitrary code execution if the expect
+               // extension is installed (T48859).
+               $oldDisable = libxml_disable_entity_loader( true );
+               $this->reader->setParserProperty( XMLReader::SUBST_ENTITIES, true );
+
+               $this->metadata['width'] = self::DEFAULT_WIDTH;
+               $this->metadata['height'] = self::DEFAULT_HEIGHT;
+
+               // The size in the units specified by the SVG file
+               // (for the metadata box)
+               // Per the SVG spec, if unspecified, default to '100%'
+               $this->metadata['originalWidth'] = '100%';
+               $this->metadata['originalHeight'] = '100%';
+
+               // 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.
+               Wikimedia\suppressWarnings();
+               try {
+                       $this->read();
+               } catch ( Exception $e ) {
+                       // Note, if this happens, the width/height will be taken to be 0x0.
+                       // Should we consider it the default 512x512 instead?
+                       Wikimedia\restoreWarnings();
+                       libxml_disable_entity_loader( $oldDisable );
+                       throw $e;
+               }
+               Wikimedia\restoreWarnings();
+               libxml_disable_entity_loader( $oldDisable );
+       }
+
+       /**
+        * @return array Array with the known metadata
+        */
+       public function getMetadata() {
+               return $this->metadata;
+       }
+
+       /**
+        * Read the SVG
+        * @throws MWException
+        * @return bool
+        */
+       protected 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( 'metadata' );
+                       } elseif ( $isSVG && $tag == 'script' ) {
+                               // We normally do not allow scripted svgs.
+                               // However its possible to configure MW to let them
+                               // in, and such files should be considered animated.
+                               $this->metadata['animated'] = true;
+                       } elseif ( $tag !== '#text' ) {
+                               $this->debug( "Unhandled top-level XML tag $tag" );
+
+                               // Recurse into children of current tag, looking for animation and languages.
+                               $this->animateFilterAndLang( $tag );
+                       }
+
+                       // Goto next element, which is sibling of current (Skip children).
+                       $keepReading = $this->reader->next();
+               }
+
+               $this->reader->close();
+
+               $this->metadata['translations'] = $this->languages + $this->languagePrefixes;
+
+               return true;
+       }
+
+       /**
+        * Read a textelement from an element
+        *
+        * @param string $name Name of the element that we are reading from
+        * @param string $metafield Field 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->reader->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 Field that we will fill with the result
+        * @throws MWException
+        */
+       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 animated elements.
+        * Also get a list of languages that can be targeted.
+        *
+        * @param string $name Name of the element that we are reading from
+        */
+       private function animateFilterAndLang( $name ) {
+               $this->debug( "animate filter for tag $name" );
+               if ( $this->reader->nodeType != XMLReader::ELEMENT ) {
+                       return;
+               }
+               if ( $this->reader->isEmptyElement ) {
+                       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
+                       ) {
+                               $sysLang = $this->reader->getAttribute( 'systemLanguage' );
+                               if ( !is_null( $sysLang ) && $sysLang !== '' ) {
+                                       // See https://www.w3.org/TR/SVG/struct.html#SystemLanguageAttribute
+                                       $langList = explode( ',', $sysLang );
+                                       foreach ( $langList as $langItem ) {
+                                               $langItem = trim( $langItem );
+                                               if ( Language::isWellFormedLanguageTag( $langItem ) ) {
+                                                       $this->languages[$langItem] = self::LANG_FULL_MATCH;
+                                               }
+                                               // Note, the standard says that any prefix should work,
+                                               // here we do only the initial prefix, since that will catch
+                                               // 99% of cases, and we are going to compare against fallbacks.
+                                               // This differs mildly from how the spec says languages should be
+                                               // handled, however it matches better how the MediaWiki language
+                                               // preference is generally handled.
+                                               $dash = strpos( $langItem, '-' );
+                                               // Intentionally checking both !false and > 0 at the same time.
+                                               if ( $dash ) {
+                                                       $itemPrefix = substr( $langItem, 0, $dash );
+                                                       if ( Language::isWellFormedLanguageTag( $itemPrefix ) ) {
+                                                               $this->languagePrefixes[$itemPrefix] = self::LANG_PREFIX_MATCH;
+                                                       }
+                                               }
+                                       }
+                               }
+                               switch ( $this->reader->localName ) {
+                                       case 'script':
+                                               // Normally we disallow files with
+                                               // <script>, but its possible
+                                               // to configure MW to disable
+                                               // such checks.
+                                       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 debug( $data ) {
+               if ( $this->mDebug ) {
+                       wfDebug( "SVGReader: $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*[\s,]\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 );
+                       $this->metadata['originalWidth'] = $this->reader->getAttribute( 'width' );
+               }
+               if ( $this->reader->getAttribute( 'height' ) ) {
+                       $height = $this->scaleSVGUnit( $this->reader->getAttribute( 'height' ), $defaultHeight );
+                       $this->metadata['originalHeight'] = $this->reader->getAttribute( 'height' );
+               }
+
+               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.
+        * https://www.w3.org/TR/SVG11/coords.html#Units
+        *
+        * @param string $length CSS/SVG length.
+        * @param float|int $viewportSize Optional scale for percentage units...
+        * @return float Length in pixels
+        */
+       static function scaleSVGUnit( $length, $viewportSize = 512 ) {
+               static $unitLength = [
+                       '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
+               ];
+               $matches = [];
+               if ( preg_match(
+                       '/^\s*([-+]?\d*(?:\.\d+|\d+)(?:[Ee][-+]?\d+)?)\s*(em|ex|px|pt|pc|cm|mm|in|%|)\s*$/',
+                       $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 );
+               }
+       }
+}