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Diffstat (limited to 'includes/media/XMP.php')
| -rw-r--r-- | includes/media/XMP.php | 1174 |
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; + } + } +} |