Update to MediaWiki 1.18.0

* also update ArchLinux skin to chagnes in MonoBook
* Use only css to hide our menu bar when printing

1 files changed, 1174 insertions, 0 deletions

diff --git a/includes/media/XMP.php b/includes/media/XMP.php
new file mode 100644
index 00000000..1e578582
--- /dev/null
+++ b/includes/media/XMP.php
@@ -0,0 +1,1174 @@
+<?php
+/**
+* Class for reading xmp data containing properties relevant to
+* images, and spitting out an array that FormatExif accepts.
+*
+* Note, this is not meant to recognize every possible thing you can
+* encode in XMP. It should recognize all the properties we want.
+* For example it doesn't have support for structures with multiple
+* nesting levels, as none of the properties we're supporting use that
+* feature. If it comes across properties it doesn't recognize, it should
+* ignore them.
+*
+* The public methods one would call in this class are
+* - parse( $content )
+*	Reads in xmp content.
+*	Can potentially be called multiple times with partial data each time.
+* - parseExtended( $content )
+*	Reads XMPExtended blocks (jpeg files only).
+* - getResults
+*	Outputs a results array.
+*
+* Note XMP kind of looks like rdf. They are not the same thing - XMP is
+* encoded as a specific subset of rdf. This class can read XMP. It cannot
+* read rdf.
+*
+*/
+class XMPReader {
+
+	private $curItem = array();        // array to hold the current element (and previous element, and so on)
+	private $ancestorStruct = false;   // the structure name when processing nested structures.
+	private $charContent = false;      // temporary holder for character data that appears in xmp doc.
+	private $mode = array();           // stores the state the xmpreader is in (see MODE_FOO constants)
+	private $results = array();        // array to hold results
+	private $processingArray = false;  // if we're doing a seq or bag.
+	private $itemLang = false;         // used for lang alts only
+
+	private $xmlParser;
+	private $charset = false;
+	private $extendedXMPOffset = 0;
+
+	protected $items;
+
+	/**
+	* These are various mode constants.
+	* they are used to figure out what to do
+	* with an element when its encountered.
+	*
+	* For example, MODE_IGNORE is used when processing
+	* a property we're not interested in. So if a new
+	* element pops up when we're in that mode, we ignore it.
+	*/
+	const MODE_INITIAL = 0;
+	const MODE_IGNORE  = 1;
+	const MODE_LI      = 2;
+	const MODE_LI_LANG = 3;
+	const MODE_QDESC   = 4;
+
+	// The following MODE constants are also used in the
+	// $items array to denote what type of property the item is.
+	const MODE_SIMPLE    = 10;
+	const MODE_STRUCT    = 11; // structure (associative array)
+	const MODE_SEQ       = 12; // ordered list
+	const MODE_BAG       = 13; // unordered list
+	const MODE_LANG      = 14;
+	const MODE_ALT       = 15; // non-language alt. Currently not implemented, and not needed atm.
+	const MODE_BAGSTRUCT = 16; // A BAG of Structs.
+
+	const NS_RDF = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
+	const NS_XML = 'http://www.w3.org/XML/1998/namespace';
+
+
+	/**
+	* Constructor.
+	*
+	* Primary job is to initialize the XMLParser
+	*/
+	function __construct() {
+
+		if ( !function_exists( 'xml_parser_create_ns' ) ) {
+			// this should already be checked by this point
+			throw new MWException( 'XMP support requires XML Parser' );
+		}
+
+		$this->items = XMPInfo::getItems();
+
+		$this->resetXMLParser();
+
+	}
+	/**
+	* Main use is if a single item has multiple xmp documents describing it.
+	* For example in jpeg's with extendedXMP
+	*/
+	private function resetXMLParser() {
+
+		if ($this->xmlParser) {
+			//is this needed?
+			xml_parser_free( $this->xmlParser );
+		}
+
+		$this->xmlParser = xml_parser_create_ns( 'UTF-8', ' ' );
+		xml_parser_set_option( $this->xmlParser, XML_OPTION_CASE_FOLDING, 0 );
+		xml_parser_set_option( $this->xmlParser, XML_OPTION_SKIP_WHITE, 1 );
+
+		xml_set_element_handler( $this->xmlParser,
+			array( $this, 'startElement' ),
+			array( $this, 'endElement' ) );
+
+		xml_set_character_data_handler( $this->xmlParser, array( $this, 'char' ) );
+	}
+
+	/** Destroy the xml parser
+	*
+	* Not sure if this is actually needed.
+	*/
+	function __destruct() {
+		// not sure if this is needed.
+		xml_parser_free( $this->xmlParser );
+	}
+
+	/** Get the result array. Do some post-processing before returning
+	* the array, and transform any metadata that is special-cased.
+	*
+	* @return Array array of results as an array of arrays suitable for
+	*	FormatMetadata::getFormattedData().
+	*/
+	public function getResults() {
+		// xmp-special is for metadata that affects how stuff
+		// is extracted. For example xmpNote:HasExtendedXMP.
+
+		// It is also used to handle photoshop:AuthorsPosition
+		// which is weird and really part of another property,
+		// see 2:85 in IPTC. See also pg 21 of IPTC4XMP standard.
+		// The location fields also use it.
+
+		$data = $this->results;
+
+		wfRunHooks('XMPGetResults', Array(&$data));
+
+		if ( isset( $data['xmp-special']['AuthorsPosition'] )
+			&& is_string( $data['xmp-special']['AuthorsPosition'] )
+			&& isset( $data['xmp-general']['Artist'][0] )
+		) {
+			// Note, if there is more than one creator,
+			// this only applies to first. This also will
+			// only apply to the dc:Creator prop, not the
+			// exif:Artist prop.
+
+			$data['xmp-general']['Artist'][0] =
+				$data['xmp-special']['AuthorsPosition'] . ', '
+				. $data['xmp-general']['Artist'][0];
+		}
+
+		// Go through the LocationShown and LocationCreated
+		// changing it to the non-hierarchal form used by
+		// the other location fields.
+
+		if ( isset( $data['xmp-special']['LocationShown'][0] )
+			&& is_array( $data['xmp-special']['LocationShown'][0] )
+		) {
+			// the is_array is just paranoia. It should always
+			// be an array.
+			foreach( $data['xmp-special']['LocationShown'] as $loc ) {
+				if ( !is_array( $loc ) ) {
+					// To avoid copying over the _type meta-fields.
+					continue;
+				}
+				foreach( $loc as $field => $val ) {
+					$data['xmp-general'][$field . 'Dest'][] = $val;
+				}
+			}
+		}
+		if ( isset( $data['xmp-special']['LocationCreated'][0] )
+			&& is_array( $data['xmp-special']['LocationCreated'][0] )
+		) {
+			// the is_array is just paranoia. It should always
+			// be an array.
+			foreach( $data['xmp-special']['LocationCreated'] as $loc ) {
+				if ( !is_array( $loc ) ) {
+					// To avoid copying over the _type meta-fields.
+					continue;
+				}
+				foreach(  $loc as $field => $val ) {
+					$data['xmp-general'][$field . 'Created'][] = $val;
+				}
+			}
+		}
+
+
+		// We don't want to return the special values, since they're
+		// special and not info to be stored about the file.
+		unset( $data['xmp-special'] );
+
+		// Convert GPSAltitude to negative if below sea level.
+		if ( isset( $data['xmp-exif']['GPSAltitudeRef'] ) ) {
+			if ( $data['xmp-exif']['GPSAltitudeRef'] == '1'
+				&& isset( $data['xmp-exif']['GPSAltitude'] )
+			) {
+				$data['xmp-exif']['GPSAltitude'] *= -1;
+			}
+			unset( $data['xmp-exif']['GPSAltitudeRef'] );
+		}
+
+		return $data;
+	}
+
+	/**
+	* Main function to call to parse XMP. Use getResults to
+	* get results.
+	*
+	* Also catches any errors during processing, writes them to
+	* debug log, blanks result array and returns false.
+	*
+	* @param String: $content XMP data
+	* @param Boolean: $allOfIt If this is all the data (true) or if its split up (false). Default true
+	* @param Boolean: $reset - does xml parser need to be reset. Default false
+	* @return Boolean success.
+	*/
+	public function parse( $content, $allOfIt = true, $reset = false ) {
+		if ( $reset ) {
+			$this->resetXMLParser();
+		}
+		try {
+
+			// detect encoding by looking for BOM which is supposed to be in processing instruction.
+			// see page 12 of http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart3.pdf
+			if ( !$this->charset ) {
+				$bom = array();
+				if ( preg_match( '/\xEF\xBB\xBF|\xFE\xFF|\x00\x00\xFE\xFF|\xFF\xFE\x00\x00|\xFF\xFE/',
+					 $content, $bom )
+				) {
+					switch ( $bom[0] ) {
+						case "\xFE\xFF":
+							$this->charset = 'UTF-16BE';
+							break;
+						case "\xFF\xFE":
+							$this->charset = 'UTF-16LE';
+							break;
+						case "\x00\x00\xFE\xFF":
+							$this->charset = 'UTF-32BE';
+							break;
+						case "\xFF\xFE\x00\x00":
+							$this->charset = 'UTF-32LE';
+							break;
+						case "\xEF\xBB\xBF":
+							$this->charset = 'UTF-8';
+							break;
+						default:
+							//this should be impossible to get to
+							throw new MWException("Invalid BOM");
+							break;
+
+					}
+
+				} else {
+					// standard specifically says, if no bom assume utf-8
+					$this->charset = 'UTF-8';
+				}
+			}
+			if ( $this->charset !== 'UTF-8' ) {
+				//don't convert if already utf-8
+				wfSuppressWarnings();
+				$content = iconv( $this->charset, 'UTF-8//IGNORE', $content );
+				wfRestoreWarnings();
+			}
+
+			$ok = xml_parse( $this->xmlParser, $content, $allOfIt );
+			if ( !$ok ) {
+				$error = xml_error_string( xml_get_error_code( $this->xmlParser ) );
+				$where = 'line: ' . xml_get_current_line_number( $this->xmlParser )
+					. ' column: ' . xml_get_current_column_number( $this->xmlParser )
+					. ' byte offset: ' . xml_get_current_byte_index( $this->xmlParser );
+
+				wfDebugLog( 'XMP', "XMPReader::parse : Error reading XMP content: $error ($where)" );
+				$this->results = array(); // blank if error.
+				return false;
+			}
+		} catch ( MWException $e ) {
+			wfDebugLog( 'XMP', 'XMP parse error: ' . $e );
+			$this->results = array();
+			return false;
+		}
+		return true;
+	}
+
+	/** Entry point for XMPExtended blocks in jpeg files
+	 *
+	 * @todo In serious need of testing
+	 * @see http://www.adobe.ge/devnet/xmp/pdfs/XMPSpecificationPart3.pdf XMP spec part 3 page 20
+	 * @param String $content XMPExtended block minus the namespace signature
+	 * @return Boolean If it succeeded.
+	 */
+	public function parseExtended( $content ) {
+		// @todo FIXME: This is untested. Hard to find example files
+		// or programs that make such files..
+		$guid = substr( $content, 0, 32 );
+		if ( !isset( $this->results['xmp-special']['HasExtendedXMP'] )
+			|| $this->results['xmp-special']['HasExtendedXMP'] !== $guid ) {
+			wfDebugLog('XMP', __METHOD__ . " Ignoring XMPExtended block due to wrong guid (guid= '$guid' )");
+			return false;
+		}
+		$len  = unpack( 'Nlength/Noffset', substr( $content, 32, 8 ) );
+
+		if (!$len || $len['length'] < 4 || $len['offset'] < 0 || $len['offset'] > $len['length'] ) {
+			wfDebugLog('XMP', __METHOD__ . 'Error reading extended XMP block, invalid length or offset.');
+			return false;
+		}
+
+
+		// we're not very robust here. we should accept it in the wrong order. To quote
+		// the xmp standard:
+		// "A JPEG writer should write the ExtendedXMP marker segments in order, immediately following the
+		// StandardXMP. However, the JPEG standard does not require preservation of marker segment order. A
+		// robust JPEG reader should tolerate the marker segments in any order."
+		//
+		// otoh the probability that an image will have more than 128k of metadata is rather low...
+		// so the probability that it will have > 128k, and be in the wrong order is very low...
+
+		if ( $len['offset'] !== $this->extendedXMPOffset ) {
+			wfDebugLog('XMP', __METHOD__ . 'Ignoring XMPExtended block due to wrong order. (Offset was '
+				. $len['offset'] . ' but expected ' . $this->extendedXMPOffset . ')');
+			return false;
+		}
+
+		if ( $len['offset'] === 0 ) {
+			// if we're starting the extended block, we've probably already
+			// done the XMPStandard block, so reset.
+			$this->resetXMLParser();
+		}
+
+		$this->extendedXMPOffset += $len['length'];
+
+		$actualContent = substr( $content, 40 );
+
+		if ( $this->extendedXMPOffset === strlen( $actualContent ) ) {
+			$atEnd = true;
+		} else {
+			$atEnd = false;
+		}
+
+		wfDebugLog('XMP', __METHOD__ . 'Parsing a XMPExtended block');
+		return $this->parse( $actualContent, $atEnd );
+	}
+
+	/**
+	* Character data handler
+	* Called whenever character data is found in the xmp document.
+	*
+	* does nothing if we're in MODE_IGNORE or if the data is whitespace
+	* throws an error if we're not in MODE_SIMPLE (as we're not allowed to have character
+	* data in the other modes).
+	*
+	* As an example, this happens when we encounter XMP like:
+	* <exif:DigitalZoomRatio>0/10</exif:DigitalZoomRatio>
+	* and are processing the 0/10 bit.
+	*
+	* @param $parser XMLParser reference to the xml parser
+	* @param $data String Character data
+	* @throws MWException on invalid data
+	*/
+	function char( $parser, $data ) {
+
+		$data = trim( $data );
+		if ( trim( $data ) === "" ) {
+			return;
+		}
+
+		if ( !isset( $this->mode[0] ) ) {
+			throw new MWException( 'Unexpected character data before first rdf:Description element' );
+		}
+
+		if ( $this->mode[0] === self::MODE_IGNORE ) return;
+
+		if ( $this->mode[0] !== self::MODE_SIMPLE
+			&& $this->mode[0] !== self::MODE_QDESC
+		) {
+			throw new MWException( 'character data where not expected. (mode ' . $this->mode[0] . ')' );
+		}
+
+		// to check, how does this handle w.s.
+		if ( $this->charContent === false ) {
+			$this->charContent = $data;
+		} else {
+			$this->charContent .= $data;
+		}
+
+	}
+
+	/** When we hit a closing element in MODE_IGNORE
+	* Check to see if this is the element we started to ignore,
+	* in which case we get out of MODE_IGNORE
+	*
+	* @param $elm String Namespace of element followed by a space and then tag name of element.
+	*/
+	private function endElementModeIgnore ( $elm ) {
+
+		if ( $this->curItem[0] === $elm ) {
+			array_shift( $this->curItem );
+			array_shift( $this->mode );
+		}
+		return;
+
+	}
+
+	/**
+	* Hit a closing element when in MODE_SIMPLE.
+	* This generally means that we finished processing a
+	* property value, and now have to save the result to the
+	* results array
+	*
+	* For example, when processing:
+	* <exif:DigitalZoomRatio>0/10</exif:DigitalZoomRatio>
+	* this deals with when we hit </exif:DigitalZoomRatio>.
+	*
+	* Or it could be if we hit the end element of a property
+	* of a compound data structure (like a member of an array).
+	*
+	* @param $elm String namespace, space, and tag name.
+	*/
+	private function endElementModeSimple ( $elm ) {
+		if ( $this->charContent !== false ) {
+			if ( $this->processingArray ) {
+				// if we're processing an array, use the original element
+				// name instead of rdf:li.
+				list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
+			} else {
+				list( $ns, $tag ) = explode( ' ', $elm, 2 );
+			}
+			$this->saveValue( $ns, $tag, $this->charContent );
+
+			$this->charContent = false; // reset
+		}
+		array_shift( $this->curItem );
+		array_shift( $this->mode );
+
+	}
+
+	/**
+	* Hit a closing element in MODE_STRUCT, MODE_SEQ, MODE_BAG
+	* generally means we've finished processing a nested structure.
+	* resets some internal variables to indicate that.
+	*
+	* Note this means we hit the </closing element> not the </rdf:Seq>.
+	*
+	* For example, when processing:
+	* <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
+	*   </rdf:Seq> </exif:ISOSpeedRatings>
+	*
+	* This method is called when we hit the </exif:ISOSpeedRatings> tag.
+	*
+	* @param $elm String namespace . space . tag name.
+	*/
+	private function endElementNested( $elm ) {
+
+		/* cur item must be the same as $elm, unless if in MODE_STRUCT
+		   in which case it could also be rdf:Description */
+		if ( $this->curItem[0] !== $elm
+			&& !( $elm === self::NS_RDF . ' Description'
+				&& $this->mode[0] === self::MODE_STRUCT )
+		 ) {
+			throw new MWException( "nesting mismatch. got a </$elm> but expected a </" . $this->curItem[0] . '>' );
+		}
+
+		// Validate structures.
+		list( $ns, $tag ) = explode( ' ', $elm, 2 );
+		if ( isset( $this->items[$ns][$tag]['validate'] ) ) {
+
+			$info =& $this->items[$ns][$tag];
+			$finalName = isset( $info['map_name'] )
+				? $info['map_name'] : $tag;
+
+			$validate = is_array( $info['validate'] ) ? $info['validate']
+				: array( 'XMPValidate', $info['validate'] );
+
+			if ( !isset( $this->results['xmp-' . $info['map_group']][$finalName] ) ) {
+				// This can happen if all the members of the struct failed validation.
+				wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> has no valid members." );
+
+			} elseif ( is_callable( $validate ) ) {
+				$val =& $this->results['xmp-' . $info['map_group']][$finalName];
+				call_user_func_array( $validate, array( $info, &$val, false ) );
+				if ( is_null( $val ) ) {
+					// the idea being the validation function will unset the variable if
+					// its invalid.
+					wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> failed validation." );
+					unset( $this->results['xmp-' . $info['map_group']][$finalName] );
+				}
+			} else {
+				wfDebugLog( 'XMP', __METHOD__ . " Validation function for $finalName ("
+					. $validate[0] . '::' . $validate[1] . '()) is not callable.' );
+			}
+		}
+
+		array_shift( $this->curItem );
+		array_shift( $this->mode );
+		$this->ancestorStruct = false;
+		$this->processingArray = false;
+		$this->itemLang = false;
+	}
+
+	/**
+	* Hit a closing element in MODE_LI (either rdf:Seq, or rdf:Bag )
+	* Add information about what type of element this is.
+	*
+	* Note we still have to hit the outer </property>
+	*
+	* For example, when processing:
+	* <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
+	*   </rdf:Seq> </exif:ISOSpeedRatings>
+	*
+	* This method is called when we hit the </rdf:Seq>.
+	* (For comparison, we call endElementModeSimple when we
+	* hit the </rdf:li>)
+	*
+	* @param $elm String namespace . ' ' . element name
+	*/
+	private function endElementModeLi( $elm ) {
+
+		list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
+		$info = $this->items[$ns][$tag];
+		$finalName = isset( $info['map_name'] )
+			? $info['map_name'] : $tag;
+
+		array_shift( $this->mode );
+
+		if ( !isset( $this->results['xmp-' . $info['map_group']][$finalName] ) ) {
+			wfDebugLog( 'XMP', __METHOD__ . " Empty compund element $finalName." );
+			return;
+		}
+
+		if ( $elm === self::NS_RDF . ' Seq' ) {
+			$this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'ol';
+		} elseif ( $elm === self::NS_RDF . ' Bag' ) {
+			$this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'ul';
+		} elseif ( $elm === self::NS_RDF . ' Alt' ) {
+			// extra if needed as you could theoretically have a non-language alt.
+			if ( $info['mode'] === self::MODE_LANG ) {
+				$this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'lang';
+			}
+
+		} else {
+			throw new MWException( __METHOD__ . " expected </rdf:seq> or </rdf:bag> but instead got $elm." );
+		}
+	}
+
+	/**
+	* End element while in MODE_QDESC
+	* mostly when ending an element when we have a simple value
+	* that has qualifiers.
+	*
+	* Qualifiers aren't all that common, and we don't do anything
+	* with them.
+	*
+	* @param $elm String namespace and element
+	*/
+	private function endElementModeQDesc( $elm ) {
+
+		if ( $elm === self::NS_RDF . ' value' ) {
+			list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
+			$this->saveValue( $ns, $tag, $this->charContent );
+			return;
+		} else {
+			array_shift( $this->mode );
+			array_shift( $this->curItem );
+		}
+
+
+	}
+
+	/**
+	* Handler for hitting a closing element.
+	*
+	* generally just calls a helper function depending on what
+	* mode we're in.
+	*
+	* Ignores the outer wrapping elements that are optional in
+	* xmp and have no meaning.
+	*
+	* @param $parser XMLParser
+	* @param $elm String namespace . ' ' . element name
+	*/
+	function endElement( $parser, $elm ) {
+		if ( $elm === ( self::NS_RDF . ' RDF' )
+			|| $elm === 'adobe:ns:meta/ xmpmeta'
+			|| $elm === 'adobe:ns:meta/ xapmeta' )
+		{
+			// ignore these.
+			return;
+		}
+
+		if ( $elm === self::NS_RDF . ' type' ) {
+			// these aren't really supported properly yet.
+			// However, it appears they almost never used.
+			wfDebugLog( 'XMP', __METHOD__ . ' encountered <rdf:type>' );
+		}
+
+		if ( strpos( $elm, ' ' ) === false ) {
+			// This probably shouldn't happen.
+			// However, there is a bug in an adobe product
+			// that forgets the namespace on some things.
+			// (Luckily they are unimportant things).
+			wfDebugLog( 'XMP', __METHOD__ . " Encountered </$elm> which has no namespace. Skipping." );
+			return;
+		}
+
+		if ( count( $this->mode[0] ) === 0 ) {
+			// This should never ever happen and means
+			// there is a pretty major bug in this class.
+			throw new MWException( 'Encountered end element with no mode' );
+		}
+
+		if ( count( $this->curItem ) == 0 && $this->mode[0] !== self::MODE_INITIAL ) {
+			// just to be paranoid. Should always have a curItem, except for initially
+			// (aka during MODE_INITAL).
+			throw new MWException( "Hit end element </$elm> but no curItem" );
+		}
+
+		switch( $this->mode[0] ) {
+			case self::MODE_IGNORE:
+				$this->endElementModeIgnore( $elm );
+				break;
+			case self::MODE_SIMPLE:
+				$this->endElementModeSimple( $elm );
+				break;
+			case self::MODE_STRUCT:
+			case self::MODE_SEQ:
+			case self::MODE_BAG:
+			case self::MODE_LANG:
+			case self::MODE_BAGSTRUCT:
+				$this->endElementNested( $elm );
+				break;
+			case self::MODE_INITIAL:
+				if ( $elm === self::NS_RDF . ' Description' ) {
+					array_shift( $this->mode );
+				} else {
+					throw new MWException( 'Element ended unexpectedly while in MODE_INITIAL' );
+				}
+				break;
+			case self::MODE_LI:
+			case self::MODE_LI_LANG:
+				$this->endElementModeLi( $elm );
+				break;
+			case self::MODE_QDESC:
+				$this->endElementModeQDesc( $elm );
+				break;
+			default:
+				wfDebugLog( 'XMP', __METHOD__ . " no mode (elm = $elm)" );
+				break;
+		}
+	}
+
+	/**
+	* Hit an opening element while in MODE_IGNORE
+	*
+	* XMP is extensible, so ignore any tag we don't understand.
+	*
+	* Mostly ignores, unless we encounter the element that we are ignoring.
+	* in which case we add it to the item stack, so we can ignore things
+	* that are nested, correctly.
+	*
+	* @param $elm String namespace . ' ' . tag name
+	*/
+	private function startElementModeIgnore( $elm ) {
+		if ( $elm === $this->curItem[0] ) {
+			array_unshift( $this->curItem, $elm );
+			array_unshift( $this->mode, self::MODE_IGNORE );
+		}
+	}
+
+	/**
+	*  Start element in MODE_BAG (unordered array)
+	* this should always be <rdf:Bag>
+	*
+	* @param $elm String namespace . ' ' . tag
+	* @throws MWException if we have an element that's not <rdf:Bag>
+	*/
+	private function startElementModeBag( $elm ) {
+		if ( $elm === self::NS_RDF . ' Bag' ) {
+			array_unshift( $this->mode, self::MODE_LI );
+		} else {
+			throw new MWException( "Expected <rdf:Bag> but got $elm." );
+		}
+
+	}
+
+	/**
+	* Start element in MODE_SEQ (ordered array)
+	* this should always be <rdf:Seq>
+	*
+	* @param $elm String namespace . ' ' . tag
+	* @throws MWException if we have an element that's not <rdf:Seq>
+	*/
+	private function startElementModeSeq( $elm ) {
+		if ( $elm === self::NS_RDF . ' Seq' ) {
+			array_unshift( $this->mode, self::MODE_LI );
+		} elseif ( $elm === self::NS_RDF . ' Bag' ) {
+			# bug 27105
+			wfDebugLog( 'XMP', __METHOD__ . ' Expected an rdf:Seq, but got an rdf:Bag. Pretending'
+				. ' it is a Seq, since some buggy software is known to screw this up.' );
+			array_unshift( $this->mode, self::MODE_LI );
+		} else {
+			throw new MWException( "Expected <rdf:Seq> but got $elm." );
+		}
+
+	}
+
+	/**
+	* Start element in MODE_LANG (language alternative)
+	* this should always be <rdf:Alt>
+	*
+	* This tag tends to be used for metadata like describe this
+	* picture, which can be translated into multiple languages.
+	*
+	* XMP supports non-linguistic alternative selections,
+	* which are really only used for thumbnails, which
+	* we don't care about.
+	*
+	* @param $elm String namespace . ' ' . tag
+	* @throws MWException if we have an element that's not <rdf:Alt>
+	*/
+	private function startElementModeLang( $elm ) {
+		if ( $elm === self::NS_RDF . ' Alt' ) {
+			array_unshift( $this->mode, self::MODE_LI_LANG );
+		} else {
+			throw new MWException( "Expected <rdf:Seq> but got $elm." );
+		}
+
+	}
+
+	/**
+	* Handle an opening element when in MODE_SIMPLE
+	*
+	* This should not happen often. This is for if a simple element
+	* already opened has a child element. Could happen for a
+	* qualified element.
+	*
+	* For example:
+	* <exif:DigitalZoomRatio><rdf:Description><rdf:value>0/10</rdf:value>
+	*   <foo:someQualifier>Bar</foo:someQualifier> </rdf:Description>
+	*   </exif:DigitalZoomRatio>
+	*
+	* This method is called when processing the <rdf:Description> element
+	*
+	* @param $elm String namespace and tag names separated by space.
+	* @param $attribs Array Attributes of the element.
+	*/
+	private function startElementModeSimple( $elm, $attribs ) {
+		if ( $elm === self::NS_RDF . ' Description' ) {
+			// If this value has qualifiers
+			array_unshift( $this->mode, self::MODE_QDESC );
+			array_unshift( $this->curItem, $this->curItem[0] );
+
+			if ( isset( $attribs[self::NS_RDF . ' value'] ) ) {
+				list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
+				$this->saveValue( $ns, $tag, $attribs[self::NS_RDF . ' value'] );
+			}
+		} elseif ( $elm === self::NS_RDF . ' value' ) {
+			// This should not be here.
+			throw new MWException( __METHOD__ . ' Encountered <rdf:value> where it was unexpected.' );
+
+		} else {
+			// something else we don't recognize, like a qualifier maybe.
+			wfDebugLog( 'XMP', __METHOD__ . " Encountered element <$elm> where only expecting character data as value of " . $this->curItem[0] );
+			array_unshift( $this->mode, self::MODE_IGNORE );
+			array_unshift( $this->curItem, $elm );
+
+		}
+
+	}
+
+	/**
+	* Start an element when in MODE_QDESC.
+	* This generally happens when a simple element has an inner
+	* rdf:Description to hold qualifier elements.
+	*
+	* For example in:
+	* <exif:DigitalZoomRatio><rdf:Description><rdf:value>0/10</rdf:value>
+	*   <foo:someQualifier>Bar</foo:someQualifier> </rdf:Description>
+	*   </exif:DigitalZoomRatio>
+	* Called when processing the <rdf:value> or <foo:someQualifier>.
+	*
+	* @param $elm String namespace and tag name separated by a space.
+	*
+	*/
+	private function startElementModeQDesc( $elm ) {
+		if ( $elm === self::NS_RDF . ' value' ) {
+			return; // do nothing
+		} else {
+			// otherwise its a qualifier, which we ignore
+			array_unshift( $this->mode, self::MODE_IGNORE );
+			array_unshift( $this->curItem, $elm );
+		}
+	}
+
+	/**
+	* Starting an element when in MODE_INITIAL
+	* This usually happens when we hit an element inside
+	* the outer rdf:Description
+	*
+	* This is generally where most properties start.
+	*
+	* @param $ns String Namespace
+	* @param $tag String tag name (without namespace prefix)
+	* @param $attribs Array array of attributes
+	*/
+	private function startElementModeInitial( $ns, $tag, $attribs ) {
+		if ( $ns !== self::NS_RDF ) {
+
+			if ( isset( $this->items[$ns][$tag] ) ) {
+				if ( isset( $this->items[$ns][$tag]['structPart'] ) ) {
+					// If this element is supposed to appear only as
+					// a child of a structure, but appears here (not as
+					// a child of a struct), then something weird is
+					// happening, so ignore this element and its children.
+
+					wfDebugLog( 'XMP', "Encountered <$ns:$tag> outside"
+						. " of its expected parent. Ignoring." );
+
+					array_unshift( $this->mode, self::MODE_IGNORE );
+					array_unshift( $this->curItem, $ns . ' ' . $tag );
+					return;
+				}
+				$mode = $this->items[$ns][$tag]['mode'];
+				array_unshift( $this->mode, $mode );
+				array_unshift( $this->curItem, $ns . ' ' . $tag );
+				if ( $mode === self::MODE_STRUCT ) {
+					$this->ancestorStruct = isset( $this->items[$ns][$tag]['map_name'] )
+						? $this->items[$ns][$tag]['map_name'] : $tag;
+				}
+				if ( $this->charContent !== false ) {
+					// Something weird.
+					// Should not happen in valid XMP.
+					throw new MWException( 'tag nested in non-whitespace characters.' );
+				}
+			} else {
+				// This element is not on our list of allowed elements so ignore.
+				wfDebugLog( 'XMP', __METHOD__ . " Ignoring unrecognized element <$ns:$tag>." );
+				array_unshift( $this->mode, self::MODE_IGNORE );
+				array_unshift( $this->curItem, $ns . ' ' . $tag );
+				return;
+			}
+
+		}
+		// process attributes
+		$this->doAttribs( $attribs );
+	}
+
+	/**
+	* Hit an opening element when in a Struct (MODE_STRUCT)
+	* This is generally for fields of a compound property.
+	*
+	* Example of a struct (abbreviated; flash has more properties):
+	*
+	* <exif:Flash> <rdf:Description> <exif:Fired>True</exif:Fired>
+	*  <exif:Mode>1</exif:Mode></rdf:Description></exif:Flash>
+	*
+	* or:
+	*
+	* <exif:Flash rdf:parseType='Resource'> <exif:Fired>True</exif:Fired>
+	*  <exif:Mode>1</exif:Mode></exif:Flash>
+	*
+	* @param $ns String namespace
+	* @param $tag String tag name (no ns)
+	* @param $attribs Array array of attribs w/ values.
+	*/
+	private function startElementModeStruct( $ns, $tag, $attribs ) {
+		if ( $ns !== self::NS_RDF ) {
+
+			if ( isset( $this->items[$ns][$tag] ) ) {
+				if ( isset( $this->items[$ns][$this->ancestorStruct]['children'] )
+					&& !isset( $this->items[$ns][$this->ancestorStruct]['children'][$tag] ) )
+				{
+					// This assumes that we don't have inter-namespace nesting
+					// which we don't in all the properties we're interested in.
+					throw new MWException( " <$tag> appeared nested in <" . $this->ancestorStruct
+						. "> where it is not allowed." );
+				}
+				array_unshift( $this->mode, $this->items[$ns][$tag]['mode'] );
+				array_unshift( $this->curItem, $ns . ' ' . $tag );
+				if ( $this->charContent !== false ) {
+					// Something weird.
+					// Should not happen in valid XMP.
+					throw new MWException( "tag <$tag> nested in non-whitespace characters (" . $this->charContent . ")." );
+				}
+			} else {
+				array_unshift( $this->mode, self::MODE_IGNORE );
+				array_unshift( $this->curItem, $elm );
+				return;
+			}
+
+		}
+
+		if ( $ns === self::NS_RDF && $tag === 'Description' ) {
+			$this->doAttribs( $attribs );
+			array_unshift( $this->mode, self::MODE_STRUCT );
+			array_unshift( $this->curItem, $this->curItem[0] );
+		}
+	}
+
+	/**
+	* opening element in MODE_LI
+	* process elements of arrays.
+	*
+	* Example:
+	* <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
+	*   </rdf:Seq> </exif:ISOSpeedRatings>
+	* This method is called when we hit the <rdf:li> element.
+	*
+	* @param $elm String: namespace . ' ' . tagname
+	* @param $attribs Array: Attributes. (needed for BAGSTRUCTS)
+	* @throws MWException if gets a tag other than <rdf:li>
+	*/
+	private function startElementModeLi( $elm, $attribs ) {
+		if ( ( $elm ) !== self::NS_RDF . ' li' ) {
+			throw new MWException( "<rdf:li> expected but got $elm." );
+		}
+
+		if ( !isset( $this->mode[1] ) ) {
+			// This should never ever ever happen. Checking for it
+			// to be paranoid.
+			throw new MWException( 'In mode Li, but no 2xPrevious mode!' );
+		}
+
+		if ( $this->mode[1] === self::MODE_BAGSTRUCT ) {
+			// This list item contains a compound (STRUCT) value.
+			array_unshift( $this->mode, self::MODE_STRUCT );
+			array_unshift( $this->curItem, $elm );
+			$this->processingArray = true;
+
+			if ( !isset( $this->curItem[1] ) ) {
+				// be paranoid.
+				throw new MWException( 'Can not find parent of BAGSTRUCT.' );
+			}
+			list( $curNS, $curTag ) = explode( ' ', $this->curItem[1] );
+			$this->ancestorStruct = isset( $this->items[$curNS][$curTag]['map_name'] )
+				? $this->items[$curNS][$curTag]['map_name'] : $curTag;
+
+			$this->doAttribs( $attribs );
+
+		} else {
+			// Normal BAG or SEQ containing simple values.
+			array_unshift( $this->mode, self::MODE_SIMPLE );
+			// need to add curItem[0] on again since one is for the specific item
+			// and one is for the entire group.
+			array_unshift( $this->curItem, $this->curItem[0] );
+			$this->processingArray = true;
+		}
+
+	}
+
+	/**
+	* Opening element in MODE_LI_LANG.
+	* process elements of language alternatives
+	*
+	* Example:
+	* <dc:title> <rdf:Alt> <rdf:li xml:lang="x-default">My house
+	*  </rdf:li> </rdf:Alt> </dc:title>
+	*
+	* This method is called when we hit the <rdf:li> element.
+	*
+	* @param $elm String namespace . ' ' . tag
+	* @param $attribs array array of elements (most importantly xml:lang)
+	* @throws MWException if gets a tag other than <rdf:li> or if no xml:lang
+	*/
+	private function startElementModeLiLang( $elm, $attribs ) {
+		if ( $elm !== self::NS_RDF . ' li' ) {
+			throw new MWException( __METHOD__ . " <rdf:li> expected but got $elm." );
+		}
+		if ( !isset( $attribs[ self::NS_XML . ' lang'] )
+			|| !preg_match( '/^[-A-Za-z0-9]{2,}$/D', $attribs[ self::NS_XML . ' lang' ] ) )
+		{
+			throw new MWException( __METHOD__
+				. " <rdf:li> did not contain, or has invalid xml:lang attribute in lang alternative" );
+		}
+
+		// Lang is case-insensitive.
+		$this->itemLang = strtolower( $attribs[ self::NS_XML . ' lang' ] );
+
+		// need to add curItem[0] on again since one is for the specific item
+		// and one is for the entire group.
+		array_unshift( $this->curItem, $this->curItem[0] );
+		array_unshift( $this->mode, self::MODE_SIMPLE );
+		$this->processingArray = true;
+	}
+
+	/**
+	* Hits an opening element.
+	* Generally just calls a helper based on what MODE we're in.
+	* Also does some initial set up for the wrapper element
+	*
+	* @param $parser XMLParser
+	* @param $elm String namespace <space> element
+	* @param $attribs Array attribute name => value
+	*/
+	function startElement( $parser, $elm, $attribs ) {
+
+		if ( $elm === self::NS_RDF . ' RDF'
+			|| $elm === 'adobe:ns:meta/ xmpmeta'
+			|| $elm === 'adobe:ns:meta/ xapmeta')
+		{
+			/* ignore. */
+			return;
+		} elseif ( $elm === self::NS_RDF . ' Description' ) {
+			if ( count( $this->mode ) === 0 ) {
+				// outer rdf:desc
+				array_unshift( $this->mode, self::MODE_INITIAL );
+			}
+		} elseif ( $elm === self::NS_RDF . ' type' ) {
+			// This doesn't support rdf:type properly.
+			// In practise I have yet to see a file that
+			// uses this element, however it is mentioned
+			// on page 25 of part 1 of the xmp standard.
+			//
+			// also it seems as if exiv2 and exiftool do not support
+			// this either (That or I misunderstand the standard)
+			wfDebugLog( 'XMP', __METHOD__ . ' Encountered <rdf:type> which isn\'t currently supported' );
+		}
+
+		if ( strpos( $elm, ' ' ) === false ) {
+			// This probably shouldn't happen.
+			wfDebugLog( 'XMP', __METHOD__ . " Encountered <$elm> which has no namespace. Skipping." );
+			return;
+		}
+
+		list( $ns, $tag ) = explode( ' ', $elm, 2 );
+
+		if ( count( $this->mode ) === 0 ) {
+			// This should not happen.
+			throw new MWException('Error extracting XMP, '
+				. "encountered <$elm> with no mode" );
+		}
+
+		switch( $this->mode[0] ) {
+			case self::MODE_IGNORE:
+				$this->startElementModeIgnore( $elm );
+				break;
+			case self::MODE_SIMPLE:
+				$this->startElementModeSimple( $elm, $attribs );
+				break;
+			case self::MODE_INITIAL:
+				$this->startElementModeInitial( $ns, $tag, $attribs );
+				break;
+			case self::MODE_STRUCT:
+				$this->startElementModeStruct( $ns, $tag, $attribs );
+				break;
+			case self::MODE_BAG:
+			case self::MODE_BAGSTRUCT:
+				$this->startElementModeBag( $elm );
+				break;
+			case self::MODE_SEQ:
+				$this->startElementModeSeq( $elm );
+				break;
+			case self::MODE_LANG:
+				$this->startElementModeLang( $elm );
+				break;
+			case self::MODE_LI_LANG:
+				$this->startElementModeLiLang( $elm, $attribs );
+				break;
+			case self::MODE_LI:
+				$this->startElementModeLi( $elm, $attribs );
+				break;
+			case self::MODE_QDESC:
+				$this->startElementModeQDesc( $elm );
+				break;
+			default:
+				throw new MWException( 'StartElement in unknown mode: ' . $this->mode[0] );
+				break;
+		}
+	}
+
+	/**
+	* Process attributes.
+	* Simple values can be stored as either a tag or attribute
+	*
+	* Often the initial <rdf:Description> tag just has all the simple
+	* properties as attributes.
+	*
+	* Example:
+	* <rdf:Description rdf:about="" xmlns:exif="http://ns.adobe.com/exif/1.0/" exif:DigitalZoomRatio="0/10">
+	*
+	* @param $attribs Array attribute=>value array.
+	*/
+	private function doAttribs( $attribs ) {
+
+		// first check for rdf:parseType attribute, as that can change
+		// how the attributes are interperted.
+
+		if ( isset( $attribs[self::NS_RDF . ' parseType'] )
+			&& $attribs[self::NS_RDF . ' parseType'] === 'Resource'
+			&& $this->mode[0] === self::MODE_SIMPLE )
+		{
+			// this is equivalent to having an inner rdf:Description
+			$this->mode[0] = self::MODE_QDESC;
+		}
+		foreach ( $attribs as $name => $val ) {
+
+
+			if ( strpos( $name, ' ' ) === false ) {
+				// This shouldn't happen, but so far some old software forgets namespace
+				// on rdf:about.
+				wfDebugLog( 'XMP', __METHOD__ . ' Encountered non-namespaced attribute: '
+					. " $name=\"$val\". Skipping. " );
+				continue;
+			}
+			list( $ns, $tag ) = explode( ' ', $name, 2 );
+			if ( $ns === self::NS_RDF ) {
+				if ( $tag === 'value' || $tag === 'resource' ) {
+					// resource is for url.
+					// value attribute is a weird way of just putting the contents.
+					$this->char( $this->xmlParser, $val );
+				}
+			} elseif ( isset( $this->items[$ns][$tag] ) ) {
+				if ( $this->mode[0] === self::MODE_SIMPLE ) {
+					throw new MWException( __METHOD__
+						. " $ns:$tag found as attribute where not allowed" );
+				}
+				$this->saveValue( $ns, $tag, $val );
+			} else {
+				wfDebugLog( 'XMP', __METHOD__ . " Ignoring unrecognized element <$ns:$tag>." );
+			}
+		}
+	}
+
+	/**
+	* Given an extracted value, save it to results array
+	*
+	* note also uses $this->ancestorStruct and
+	* $this->processingArray to determine what name to
+	* save the value under. (in addition to $tag).
+	*
+	* @param $ns String namespace of tag this is for
+	* @param $tag String tag name
+	* @param $val String value to save
+	*/
+	private function saveValue( $ns, $tag, $val ) {
+
+		$info =& $this->items[$ns][$tag];
+		$finalName = isset( $info['map_name'] )
+			? $info['map_name'] : $tag;
+		if ( isset( $info['validate'] ) ) {
+			$validate = is_array( $info['validate'] ) ? $info['validate']
+				: array( 'XMPValidate', $info['validate'] );
+
+			if ( is_callable( $validate ) ) {
+				call_user_func_array( $validate, array( $info, &$val, true ) );
+				// the reasoning behind using &$val instead of using the return value
+				// is to be consistent between here and validating structures.
+				if ( is_null( $val ) ) {
+					wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> failed validation." );
+					return;
+				}
+			} else {
+				wfDebugLog( 'XMP', __METHOD__ . " Validation function for $finalName ("
+					. $validate[0] . '::' . $validate[1] . '()) is not callable.' );
+			}
+		}
+
+		if ( $this->ancestorStruct && $this->processingArray ) {
+			// Aka both an array and a struct. ( self::MODE_BAGSTRUCT )
+			$this->results['xmp-' . $info['map_group']][$this->ancestorStruct][][$finalName] = $val;
+		} elseif ( $this->ancestorStruct ) {
+			$this->results['xmp-' . $info['map_group']][$this->ancestorStruct][$finalName] = $val;
+		} elseif ( $this->processingArray ) {
+			if ( $this->itemLang === false ) {
+				// normal array
+				$this->results['xmp-' . $info['map_group']][$finalName][] = $val;
+			} else {
+				// lang array.
+				$this->results['xmp-' . $info['map_group']][$finalName][$this->itemLang] = $val;
+			}
+		} else {
+			$this->results['xmp-' . $info['map_group']][$finalName] = $val;
+		}
+	}
+}