includes/media/XMP.php

   1 <?php
   2 /**
   3  * Reader for XMP data containing properties relevant to images.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 /**
  25  * Class for reading xmp data containing properties relevant to
  26  * images, and spitting out an array that FormatMetadata accepts.
  27  *
  28  * Note, this is not meant to recognize every possible thing you can
  29  * encode in XMP. It should recognize all the properties we want.
  30  * For example it doesn't have support for structures with multiple
  31  * nesting levels, as none of the properties we're supporting use that
  32  * feature. If it comes across properties it doesn't recognize, it should
  33  * ignore them.
  34  *
  35  * The public methods one would call in this class are
  36  * - parse( $content )
  37  *    Reads in xmp content.
  38  *    Can potentially be called multiple times with partial data each time.
  39  * - parseExtended( $content )
  40  *    Reads XMPExtended blocks (jpeg files only).
  41  * - getResults
  42  *    Outputs a results array.
  43  *
  44  * Note XMP kind of looks like rdf. They are not the same thing - XMP is
  45  * encoded as a specific subset of rdf. This class can read XMP. It cannot
  46  * read rdf.
  47  *
  48  */
  49 class XMPReader {
  50         /** @var array XMP item configuration array */
  51         protected $items;
  52
  53         /** @var array Array to hold the current element (and previous element, and so on) */
  54         private $curItem = array();
  55
  56         /** @var bool|string The structure name when processing nested structures. */
  57         private $ancestorStruct = false;
  58
  59         /** @var bool|string Temporary holder for character data that appears in xmp doc. */
  60         private $charContent = false;
  61
  62         /** @var array Stores the state the xmpreader is in (see MODE_FOO constants) */
  63         private $mode = array();
  64
  65         /** @var array Array to hold results */
  66         private $results = array();
  67
  68         /** @var bool If we're doing a seq or bag. */
  69         private $processingArray = false;
  70
  71         /** @var bool|string Used for lang alts only */
  72         private $itemLang = false;
  73
  74         /** @var resource A resource handle for the XML parser */
  75         private $xmlParser;
  76
  77         /** @var bool|string Character set like 'UTF-8' */
  78         private $charset = false;
  79
  80         /** @var int */
  81         private $extendedXMPOffset = 0;
  82
  83         /**
  84          * These are various mode constants.
  85          * they are used to figure out what to do
  86          * with an element when its encountered.
  87          *
  88          * For example, MODE_IGNORE is used when processing
  89          * a property we're not interested in. So if a new
  90          * element pops up when we're in that mode, we ignore it.
  91          */
  92         const MODE_INITIAL = 0;
  93         const MODE_IGNORE = 1;
  94         const MODE_LI = 2;
  95         const MODE_LI_LANG = 3;
  96         const MODE_QDESC = 4;
  97
  98         // The following MODE constants are also used in the
  99         // $items array to denote what type of property the item is.
 100         const MODE_SIMPLE = 10;
 101         const MODE_STRUCT = 11; // structure (associative array)
 102         const MODE_SEQ = 12; // ordered list
 103         const MODE_BAG = 13; // unordered list
 104         const MODE_LANG = 14;
 105         const MODE_ALT = 15; // non-language alt. Currently not implemented, and not needed atm.
 106         const MODE_BAGSTRUCT = 16; // A BAG of Structs.
 107
 108         const NS_RDF = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
 109         const NS_XML = 'http://www.w3.org/XML/1998/namespace';
 110
 111         /**
 112          * Constructor.
 113          *
 114          * Primary job is to initialize the XMLParser
 115          */
 116         function __construct() {
 117
 118                 if ( !function_exists( 'xml_parser_create_ns' ) ) {
 119                         // this should already be checked by this point
 120                         throw new MWException( 'XMP support requires XML Parser' );
 121                 }
 122
 123                 $this->items = XMPInfo::getItems();
 124
 125                 $this->resetXMLParser();
 126         }
 127
 128         /**
 129          * Main use is if a single item has multiple xmp documents describing it.
 130          * For example in jpeg's with extendedXMP
 131          */
 132         private function resetXMLParser() {
 133
 134                 if ( $this->xmlParser ) {
 135                         //is this needed?
 136                         xml_parser_free( $this->xmlParser );
 137                 }
 138
 139                 $this->xmlParser = xml_parser_create_ns( 'UTF-8', ' ' );
 140                 xml_parser_set_option( $this->xmlParser, XML_OPTION_CASE_FOLDING, 0 );
 141                 xml_parser_set_option( $this->xmlParser, XML_OPTION_SKIP_WHITE, 1 );
 142
 143                 xml_set_element_handler( $this->xmlParser,
 144                         array( $this, 'startElement' ),
 145                         array( $this, 'endElement' ) );
 146
 147                 xml_set_character_data_handler( $this->xmlParser, array( $this, 'char' ) );
 148         }
 149
 150         /** Destroy the xml parser
 151          *
 152          * Not sure if this is actually needed.
 153          */
 154         function __destruct() {
 155                 // not sure if this is needed.
 156                 xml_parser_free( $this->xmlParser );
 157         }
 158
 159         /** Get the result array. Do some post-processing before returning
 160          * the array, and transform any metadata that is special-cased.
 161          *
 162          * @return array Array of results as an array of arrays suitable for
 163          *    FormatMetadata::getFormattedData().
 164          */
 165         public function getResults() {
 166                 // xmp-special is for metadata that affects how stuff
 167                 // is extracted. For example xmpNote:HasExtendedXMP.
 168
 169                 // It is also used to handle photoshop:AuthorsPosition
 170                 // which is weird and really part of another property,
 171                 // see 2:85 in IPTC. See also pg 21 of IPTC4XMP standard.
 172                 // The location fields also use it.
 173
 174                 $data = $this->results;
 175
 176                 wfRunHooks( 'XMPGetResults', array( &$data ) );
 177
 178                 if ( isset( $data['xmp-special']['AuthorsPosition'] )
 179                         && is_string( $data['xmp-special']['AuthorsPosition'] )
 180                         && isset( $data['xmp-general']['Artist'][0] )
 181                 ) {
 182                         // Note, if there is more than one creator,
 183                         // this only applies to first. This also will
 184                         // only apply to the dc:Creator prop, not the
 185                         // exif:Artist prop.
 186
 187                         $data['xmp-general']['Artist'][0] =
 188                                 $data['xmp-special']['AuthorsPosition'] . ', '
 189                                 . $data['xmp-general']['Artist'][0];
 190                 }
 191
 192                 // Go through the LocationShown and LocationCreated
 193                 // changing it to the non-hierarchal form used by
 194                 // the other location fields.
 195
 196                 if ( isset( $data['xmp-special']['LocationShown'][0] )
 197                         && is_array( $data['xmp-special']['LocationShown'][0] )
 198                 ) {
 199                         // the is_array is just paranoia. It should always
 200                         // be an array.
 201                         foreach ( $data['xmp-special']['LocationShown'] as $loc ) {
 202                                 if ( !is_array( $loc ) ) {
 203                                         // To avoid copying over the _type meta-fields.
 204                                         continue;
 205                                 }
 206                                 foreach ( $loc as $field => $val ) {
 207                                         $data['xmp-general'][$field . 'Dest'][] = $val;
 208                                 }
 209                         }
 210                 }
 211                 if ( isset( $data['xmp-special']['LocationCreated'][0] )
 212                         && is_array( $data['xmp-special']['LocationCreated'][0] )
 213                 ) {
 214                         // the is_array is just paranoia. It should always
 215                         // be an array.
 216                         foreach ( $data['xmp-special']['LocationCreated'] as $loc ) {
 217                                 if ( !is_array( $loc ) ) {
 218                                         // To avoid copying over the _type meta-fields.
 219                                         continue;
 220                                 }
 221                                 foreach ( $loc as $field => $val ) {
 222                                         $data['xmp-general'][$field . 'Created'][] = $val;
 223                                 }
 224                         }
 225                 }
 226
 227                 // We don't want to return the special values, since they're
 228                 // special and not info to be stored about the file.
 229                 unset( $data['xmp-special'] );
 230
 231                 // Convert GPSAltitude to negative if below sea level.
 232                 if ( isset( $data['xmp-exif']['GPSAltitudeRef'] )
 233                         && isset( $data['xmp-exif']['GPSAltitude'] )
 234                 ) {
 235
 236                         // Must convert to a real before multiplying by -1
 237                         // XMPValidate guarantees there will always be a '/' in this value.
 238                         list( $nom, $denom ) = explode( '/', $data['xmp-exif']['GPSAltitude'] );
 239                         $data['xmp-exif']['GPSAltitude'] = $nom / $denom;
 240
 241                         if ( $data['xmp-exif']['GPSAltitudeRef'] == '1' ) {
 242                                 $data['xmp-exif']['GPSAltitude'] *= -1;
 243                         }
 244                         unset( $data['xmp-exif']['GPSAltitudeRef'] );
 245                 }
 246
 247                 return $data;
 248         }
 249
 250         /**
 251          * Main function to call to parse XMP. Use getResults to
 252          * get results.
 253          *
 254          * Also catches any errors during processing, writes them to
 255          * debug log, blanks result array and returns false.
 256          *
 257          * @param string $content XMP data
 258          * @param bool $allOfIt If this is all the data (true) or if its split up (false). Default true
 259          * @param bool $reset Does xml parser need to be reset. Default false
 260          * @throws MWException
 261          * @return bool Success.
 262          */
 263         public function parse( $content, $allOfIt = true, $reset = false ) {
 264                 if ( $reset ) {
 265                         $this->resetXMLParser();
 266                 }
 267                 try {
 268
 269                         // detect encoding by looking for BOM which is supposed to be in processing instruction.
 270                         // see page 12 of http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart3.pdf
 271                         if ( !$this->charset ) {
 272                                 $bom = array();
 273                                 if ( preg_match( '/\xEF\xBB\xBF|\xFE\xFF|\x00\x00\xFE\xFF|\xFF\xFE\x00\x00|\xFF\xFE/',
 274                                         $content, $bom )
 275                                 ) {
 276                                         switch ( $bom[0] ) {
 277                                                 case "\xFE\xFF":
 278                                                         $this->charset = 'UTF-16BE';
 279                                                         break;
 280                                                 case "\xFF\xFE":
 281                                                         $this->charset = 'UTF-16LE';
 282                                                         break;
 283                                                 case "\x00\x00\xFE\xFF":
 284                                                         $this->charset = 'UTF-32BE';
 285                                                         break;
 286                                                 case "\xFF\xFE\x00\x00":
 287                                                         $this->charset = 'UTF-32LE';
 288                                                         break;
 289                                                 case "\xEF\xBB\xBF":
 290                                                         $this->charset = 'UTF-8';
 291                                                         break;
 292                                                 default:
 293                                                         //this should be impossible to get to
 294                                                         throw new MWException( "Invalid BOM" );
 295                                         }
 296                                 } else {
 297                                         // standard specifically says, if no bom assume utf-8
 298                                         $this->charset = 'UTF-8';
 299                                 }
 300                         }
 301                         if ( $this->charset !== 'UTF-8' ) {
 302                                 //don't convert if already utf-8
 303                                 wfSuppressWarnings();
 304                                 $content = iconv( $this->charset, 'UTF-8//IGNORE', $content );
 305                                 wfRestoreWarnings();
 306                         }
 307
 308                         $ok = xml_parse( $this->xmlParser, $content, $allOfIt );
 309                         if ( !$ok ) {
 310                                 $error = xml_error_string( xml_get_error_code( $this->xmlParser ) );
 311                                 $where = 'line: ' . xml_get_current_line_number( $this->xmlParser )
 312                                         . ' column: ' . xml_get_current_column_number( $this->xmlParser )
 313                                         . ' byte offset: ' . xml_get_current_byte_index( $this->xmlParser );
 314
 315                                 wfDebugLog( 'XMP', "XMPReader::parse : Error reading XMP content: $error ($where)" );
 316                                 $this->results = array(); // blank if error.
 317                                 return false;
 318                         }
 319                 } catch ( MWException $e ) {
 320                         wfDebugLog( 'XMP', 'XMP parse error: ' . $e );
 321                         $this->results = array();
 322
 323                         return false;
 324                 }
 325
 326                 return true;
 327         }
 328
 329         /** Entry point for XMPExtended blocks in jpeg files
 330          *
 331          * @todo In serious need of testing
 332          * @see http://www.adobe.ge/devnet/xmp/pdfs/XMPSpecificationPart3.pdf XMP spec part 3 page 20
 333          * @param string $content XMPExtended block minus the namespace signature
 334          * @return bool If it succeeded.
 335          */
 336         public function parseExtended( $content ) {
 337                 // @todo FIXME: This is untested. Hard to find example files
 338                 // or programs that make such files..
 339                 $guid = substr( $content, 0, 32 );
 340                 if ( !isset( $this->results['xmp-special']['HasExtendedXMP'] )
 341                         || $this->results['xmp-special']['HasExtendedXMP'] !== $guid
 342                 ) {
 343                         wfDebugLog( 'XMP', __METHOD__ .
 344                                 " Ignoring XMPExtended block due to wrong guid (guid= '$guid')" );
 345
 346                         return false;
 347                 }
 348                 $len = unpack( 'Nlength/Noffset', substr( $content, 32, 8 ) );
 349
 350                 if ( !$len || $len['length'] < 4 || $len['offset'] < 0 || $len['offset'] > $len['length'] ) {
 351                         wfDebugLog( 'XMP', __METHOD__ . 'Error reading extended XMP block, invalid length or offset.' );
 352
 353                         return false;
 354                 }
 355
 356                 // we're not very robust here. we should accept it in the wrong order.
 357                 // To quote the XMP standard:
 358                 // "A JPEG writer should write the ExtendedXMP marker segments in order,
 359                 // immediately following the StandardXMP. However, the JPEG standard
 360                 // does not require preservation of marker segment order. A robust JPEG
 361                 // reader should tolerate the marker segments in any order."
 362                 //
 363                 // otoh the probability that an image will have more than 128k of
 364                 // metadata is rather low... so the probability that it will have
 365                 // > 128k, and be in the wrong order is very low...
 366
 367                 if ( $len['offset'] !== $this->extendedXMPOffset ) {
 368                         wfDebugLog( 'XMP', __METHOD__ . 'Ignoring XMPExtended block due to wrong order. (Offset was '
 369                                 . $len['offset'] . ' but expected ' . $this->extendedXMPOffset . ')' );
 370
 371                         return false;
 372                 }
 373
 374                 if ( $len['offset'] === 0 ) {
 375                         // if we're starting the extended block, we've probably already
 376                         // done the XMPStandard block, so reset.
 377                         $this->resetXMLParser();
 378                 }
 379
 380                 $this->extendedXMPOffset += $len['length'];
 381
 382                 $actualContent = substr( $content, 40 );
 383
 384                 if ( $this->extendedXMPOffset === strlen( $actualContent ) ) {
 385                         $atEnd = true;
 386                 } else {
 387                         $atEnd = false;
 388                 }
 389
 390                 wfDebugLog( 'XMP', __METHOD__ . 'Parsing a XMPExtended block' );
 391
 392                 return $this->parse( $actualContent, $atEnd );
 393         }
 394
 395         /**
 396          * Character data handler
 397          * Called whenever character data is found in the xmp document.
 398          *
 399          * does nothing if we're in MODE_IGNORE or if the data is whitespace
 400          * throws an error if we're not in MODE_SIMPLE (as we're not allowed to have character
 401          * data in the other modes).
 402          *
 403          * As an example, this happens when we encounter XMP like:
 404          * <exif:DigitalZoomRatio>0/10</exif:DigitalZoomRatio>
 405          * and are processing the 0/10 bit.
 406          *
 407          * @param XMLParser $parser XMLParser reference to the xml parser
 408          * @param string $data Character data
 409          * @throws MWException On invalid data
 410          */
 411         function char( $parser, $data ) {
 412
 413                 $data = trim( $data );
 414                 if ( trim( $data ) === "" ) {
 415                         return;
 416                 }
 417
 418                 if ( !isset( $this->mode[0] ) ) {
 419                         throw new MWException( 'Unexpected character data before first rdf:Description element' );
 420                 }
 421
 422                 if ( $this->mode[0] === self::MODE_IGNORE ) {
 423                         return;
 424                 }
 425
 426                 if ( $this->mode[0] !== self::MODE_SIMPLE
 427                         && $this->mode[0] !== self::MODE_QDESC
 428                 ) {
 429                         throw new MWException( 'character data where not expected. (mode ' . $this->mode[0] . ')' );
 430                 }
 431
 432                 // to check, how does this handle w.s.
 433                 if ( $this->charContent === false ) {
 434                         $this->charContent = $data;
 435                 } else {
 436                         $this->charContent .= $data;
 437                 }
 438         }
 439
 440         /** When we hit a closing element in MODE_IGNORE
 441          * Check to see if this is the element we started to ignore,
 442          * in which case we get out of MODE_IGNORE
 443          *
 444          * @param string $elm Namespace of element followed by a space and then tag name of element.
 445          */
 446         private function endElementModeIgnore( $elm ) {
 447                 if ( $this->curItem[0] === $elm ) {
 448                         array_shift( $this->curItem );
 449                         array_shift( $this->mode );
 450                 }
 451         }
 452
 453         /**
 454          * Hit a closing element when in MODE_SIMPLE.
 455          * This generally means that we finished processing a
 456          * property value, and now have to save the result to the
 457          * results array
 458          *
 459          * For example, when processing:
 460          * <exif:DigitalZoomRatio>0/10</exif:DigitalZoomRatio>
 461          * this deals with when we hit </exif:DigitalZoomRatio>.
 462          *
 463          * Or it could be if we hit the end element of a property
 464          * of a compound data structure (like a member of an array).
 465          *
 466          * @param string $elm Namespace, space, and tag name.
 467          */
 468         private function endElementModeSimple( $elm ) {
 469                 if ( $this->charContent !== false ) {
 470                         if ( $this->processingArray ) {
 471                                 // if we're processing an array, use the original element
 472                                 // name instead of rdf:li.
 473                                 list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
 474                         } else {
 475                                 list( $ns, $tag ) = explode( ' ', $elm, 2 );
 476                         }
 477                         $this->saveValue( $ns, $tag, $this->charContent );
 478
 479                         $this->charContent = false; // reset
 480                 }
 481                 array_shift( $this->curItem );
 482                 array_shift( $this->mode );
 483         }
 484
 485         /**
 486          * Hit a closing element in MODE_STRUCT, MODE_SEQ, MODE_BAG
 487          * generally means we've finished processing a nested structure.
 488          * resets some internal variables to indicate that.
 489          *
 490          * Note this means we hit the closing element not the "</rdf:Seq>".
 491          *
 492          * @par For example, when processing:
 493          * @code{,xml}
 494          * <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
 495          *   </rdf:Seq> </exif:ISOSpeedRatings>
 496          * @endcode
 497          *
 498          * This method is called when we hit the "</exif:ISOSpeedRatings>" tag.
 499          *
 500          * @param string $elm Namespace . space . tag name.
 501          * @throws MWException
 502          */
 503         private function endElementNested( $elm ) {
 504
 505                 /* cur item must be the same as $elm, unless if in MODE_STRUCT
 506                    in which case it could also be rdf:Description */
 507                 if ( $this->curItem[0] !== $elm
 508                         && !( $elm === self::NS_RDF . ' Description'
 509                                 && $this->mode[0] === self::MODE_STRUCT )
 510                 ) {
 511                         throw new MWException( "nesting mismatch. got a </$elm> but expected a </" .
 512                                 $this->curItem[0] . '>' );
 513                 }
 514
 515                 // Validate structures.
 516                 list( $ns, $tag ) = explode( ' ', $elm, 2 );
 517                 if ( isset( $this->items[$ns][$tag]['validate'] ) ) {
 518
 519                         $info =& $this->items[$ns][$tag];
 520                         $finalName = isset( $info['map_name'] )
 521                                 ? $info['map_name'] : $tag;
 522
 523                         $validate = is_array( $info['validate'] ) ? $info['validate']
 524                                 : array( 'XMPValidate', $info['validate'] );
 525
 526                         if ( !isset( $this->results['xmp-' . $info['map_group']][$finalName] ) ) {
 527                                 // This can happen if all the members of the struct failed validation.
 528                                 wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> has no valid members." );
 529                         } elseif ( is_callable( $validate ) ) {
 530                                 $val =& $this->results['xmp-' . $info['map_group']][$finalName];
 531                                 call_user_func_array( $validate, array( $info, &$val, false ) );
 532                                 if ( is_null( $val ) ) {
 533                                         // the idea being the validation function will unset the variable if
 534                                         // its invalid.
 535                                         wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> failed validation." );
 536                                         unset( $this->results['xmp-' . $info['map_group']][$finalName] );
 537                                 }
 538                         } else {
 539                                 wfDebugLog( 'XMP', __METHOD__ . " Validation function for $finalName ("
 540                                         . $validate[0] . '::' . $validate[1] . '()) is not callable.' );
 541                         }
 542                 }
 543
 544                 array_shift( $this->curItem );
 545                 array_shift( $this->mode );
 546                 $this->ancestorStruct = false;
 547                 $this->processingArray = false;
 548                 $this->itemLang = false;
 549         }
 550
 551         /**
 552          * Hit a closing element in MODE_LI (either rdf:Seq, or rdf:Bag )
 553          * Add information about what type of element this is.
 554          *
 555          * Note we still have to hit the outer "</property>"
 556          *
 557          * @par For example, when processing:
 558          * @code{,xml}
 559          * <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
 560          *   </rdf:Seq> </exif:ISOSpeedRatings>
 561          * @endcode
 562          *
 563          * This method is called when we hit the "</rdf:Seq>".
 564          * (For comparison, we call endElementModeSimple when we
 565          * hit the "</rdf:li>")
 566          *
 567          * @param string $elm Namespace . ' ' . element name
 568          * @throws MWException
 569          */
 570         private function endElementModeLi( $elm ) {
 571
 572                 list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
 573                 $info = $this->items[$ns][$tag];
 574                 $finalName = isset( $info['map_name'] )
 575                         ? $info['map_name'] : $tag;
 576
 577                 array_shift( $this->mode );
 578
 579                 if ( !isset( $this->results['xmp-' . $info['map_group']][$finalName] ) ) {
 580                         wfDebugLog( 'XMP', __METHOD__ . " Empty compund element $finalName." );
 581
 582                         return;
 583                 }
 584
 585                 if ( $elm === self::NS_RDF . ' Seq' ) {
 586                         $this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'ol';
 587                 } elseif ( $elm === self::NS_RDF . ' Bag' ) {
 588                         $this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'ul';
 589                 } elseif ( $elm === self::NS_RDF . ' Alt' ) {
 590                         // extra if needed as you could theoretically have a non-language alt.
 591                         if ( $info['mode'] === self::MODE_LANG ) {
 592                                 $this->results['xmp-' . $info['map_group']][$finalName]['_type'] = 'lang';
 593                         }
 594                 } else {
 595                         throw new MWException( __METHOD__ . " expected </rdf:seq> or </rdf:bag> but instead got $elm." );
 596                 }
 597         }
 598
 599         /**
 600          * End element while in MODE_QDESC
 601          * mostly when ending an element when we have a simple value
 602          * that has qualifiers.
 603          *
 604          * Qualifiers aren't all that common, and we don't do anything
 605          * with them.
 606          *
 607          * @param string $elm Namespace and element
 608          */
 609         private function endElementModeQDesc( $elm ) {
 610
 611                 if ( $elm === self::NS_RDF . ' value' ) {
 612                         list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
 613                         $this->saveValue( $ns, $tag, $this->charContent );
 614
 615                         return;
 616                 } else {
 617                         array_shift( $this->mode );
 618                         array_shift( $this->curItem );
 619                 }
 620         }
 621
 622         /**
 623          * Handler for hitting a closing element.
 624          *
 625          * generally just calls a helper function depending on what
 626          * mode we're in.
 627          *
 628          * Ignores the outer wrapping elements that are optional in
 629          * xmp and have no meaning.
 630          *
 631          * @param XMLParser $parser
 632          * @param string $elm Namespace . ' ' . element name
 633          * @throws MWException
 634          */
 635         function endElement( $parser, $elm ) {
 636                 if ( $elm === ( self::NS_RDF . ' RDF' )
 637                         || $elm === 'adobe:ns:meta/ xmpmeta'
 638                         || $elm === 'adobe:ns:meta/ xapmeta'
 639                 ) {
 640                         // ignore these.
 641                         return;
 642                 }
 643
 644                 if ( $elm === self::NS_RDF . ' type' ) {
 645                         // these aren't really supported properly yet.
 646                         // However, it appears they almost never used.
 647                         wfDebugLog( 'XMP', __METHOD__ . ' encountered <rdf:type>' );
 648                 }
 649
 650                 if ( strpos( $elm, ' ' ) === false ) {
 651                         // This probably shouldn't happen.
 652                         // However, there is a bug in an adobe product
 653                         // that forgets the namespace on some things.
 654                         // (Luckily they are unimportant things).
 655                         wfDebugLog( 'XMP', __METHOD__ . " Encountered </$elm> which has no namespace. Skipping." );
 656
 657                         return;
 658                 }
 659
 660                 if ( count( $this->mode[0] ) === 0 ) {
 661                         // This should never ever happen and means
 662                         // there is a pretty major bug in this class.
 663                         throw new MWException( 'Encountered end element with no mode' );
 664                 }
 665
 666                 if ( count( $this->curItem ) == 0 && $this->mode[0] !== self::MODE_INITIAL ) {
 667                         // just to be paranoid. Should always have a curItem, except for initially
 668                         // (aka during MODE_INITAL).
 669                         throw new MWException( "Hit end element </$elm> but no curItem" );
 670                 }
 671
 672                 switch ( $this->mode[0] ) {
 673                         case self::MODE_IGNORE:
 674                                 $this->endElementModeIgnore( $elm );
 675                                 break;
 676                         case self::MODE_SIMPLE:
 677                                 $this->endElementModeSimple( $elm );
 678                                 break;
 679                         case self::MODE_STRUCT:
 680                         case self::MODE_SEQ:
 681                         case self::MODE_BAG:
 682                         case self::MODE_LANG:
 683                         case self::MODE_BAGSTRUCT:
 684                                 $this->endElementNested( $elm );
 685                                 break;
 686                         case self::MODE_INITIAL:
 687                                 if ( $elm === self::NS_RDF . ' Description' ) {
 688                                         array_shift( $this->mode );
 689                                 } else {
 690                                         throw new MWException( 'Element ended unexpectedly while in MODE_INITIAL' );
 691                                 }
 692                                 break;
 693                         case self::MODE_LI:
 694                         case self::MODE_LI_LANG:
 695                                 $this->endElementModeLi( $elm );
 696                                 break;
 697                         case self::MODE_QDESC:
 698                                 $this->endElementModeQDesc( $elm );
 699                                 break;
 700                         default:
 701                                 wfDebugLog( 'XMP', __METHOD__ . " no mode (elm = $elm)" );
 702                                 break;
 703                 }
 704         }
 705
 706         /**
 707          * Hit an opening element while in MODE_IGNORE
 708          *
 709          * XMP is extensible, so ignore any tag we don't understand.
 710          *
 711          * Mostly ignores, unless we encounter the element that we are ignoring.
 712          * in which case we add it to the item stack, so we can ignore things
 713          * that are nested, correctly.
 714          *
 715          * @param string $elm Namespace . ' ' . tag name
 716          */
 717         private function startElementModeIgnore( $elm ) {
 718                 if ( $elm === $this->curItem[0] ) {
 719                         array_unshift( $this->curItem, $elm );
 720                         array_unshift( $this->mode, self::MODE_IGNORE );
 721                 }
 722         }
 723
 724         /**
 725          *  Start element in MODE_BAG (unordered array)
 726          * this should always be <rdf:Bag>
 727          *
 728          * @param string $elm Namespace . ' ' . tag
 729          * @throws MWException If we have an element that's not <rdf:Bag>
 730          */
 731         private function startElementModeBag( $elm ) {
 732                 if ( $elm === self::NS_RDF . ' Bag' ) {
 733                         array_unshift( $this->mode, self::MODE_LI );
 734                 } else {
 735                         throw new MWException( "Expected <rdf:Bag> but got $elm." );
 736                 }
 737         }
 738
 739         /**
 740          * Start element in MODE_SEQ (ordered array)
 741          * this should always be <rdf:Seq>
 742          *
 743          * @param string $elm Namespace . ' ' . tag
 744          * @throws MWException If we have an element that's not <rdf:Seq>
 745          */
 746         private function startElementModeSeq( $elm ) {
 747                 if ( $elm === self::NS_RDF . ' Seq' ) {
 748                         array_unshift( $this->mode, self::MODE_LI );
 749                 } elseif ( $elm === self::NS_RDF . ' Bag' ) {
 750                         # bug 27105
 751                         wfDebugLog( 'XMP', __METHOD__ . ' Expected an rdf:Seq, but got an rdf:Bag. Pretending'
 752                                 . ' it is a Seq, since some buggy software is known to screw this up.' );
 753                         array_unshift( $this->mode, self::MODE_LI );
 754                 } else {
 755                         throw new MWException( "Expected <rdf:Seq> but got $elm." );
 756                 }
 757         }
 758
 759         /**
 760          * Start element in MODE_LANG (language alternative)
 761          * this should always be <rdf:Alt>
 762          *
 763          * This tag tends to be used for metadata like describe this
 764          * picture, which can be translated into multiple languages.
 765          *
 766          * XMP supports non-linguistic alternative selections,
 767          * which are really only used for thumbnails, which
 768          * we don't care about.
 769          *
 770          * @param string $elm Namespace . ' ' . tag
 771          * @throws MWException If we have an element that's not <rdf:Alt>
 772          */
 773         private function startElementModeLang( $elm ) {
 774                 if ( $elm === self::NS_RDF . ' Alt' ) {
 775                         array_unshift( $this->mode, self::MODE_LI_LANG );
 776                 } else {
 777                         throw new MWException( "Expected <rdf:Seq> but got $elm." );
 778                 }
 779         }
 780
 781         /**
 782          * Handle an opening element when in MODE_SIMPLE
 783          *
 784          * This should not happen often. This is for if a simple element
 785          * already opened has a child element. Could happen for a
 786          * qualified element.
 787          *
 788          * For example:
 789          * <exif:DigitalZoomRatio><rdf:Description><rdf:value>0/10</rdf:value>
 790          *   <foo:someQualifier>Bar</foo:someQualifier> </rdf:Description>
 791          *   </exif:DigitalZoomRatio>
 792          *
 793          * This method is called when processing the <rdf:Description> element
 794          *
 795          * @param string $elm Namespace and tag names separated by space.
 796          * @param array $attribs Attributes of the element.
 797          * @throws MWException
 798          */
 799         private function startElementModeSimple( $elm, $attribs ) {
 800                 if ( $elm === self::NS_RDF . ' Description' ) {
 801                         // If this value has qualifiers
 802                         array_unshift( $this->mode, self::MODE_QDESC );
 803                         array_unshift( $this->curItem, $this->curItem[0] );
 804
 805                         if ( isset( $attribs[self::NS_RDF . ' value'] ) ) {
 806                                 list( $ns, $tag ) = explode( ' ', $this->curItem[0], 2 );
 807                                 $this->saveValue( $ns, $tag, $attribs[self::NS_RDF . ' value'] );
 808                         }
 809                 } elseif ( $elm === self::NS_RDF . ' value' ) {
 810                         // This should not be here.
 811                         throw new MWException( __METHOD__ . ' Encountered <rdf:value> where it was unexpected.' );
 812                 } else {
 813                         // something else we don't recognize, like a qualifier maybe.
 814                         wfDebugLog( 'XMP', __METHOD__ .
 815                                 " Encountered element <$elm> where only expecting character data as value of " .
 816                                 $this->curItem[0] );
 817                         array_unshift( $this->mode, self::MODE_IGNORE );
 818                         array_unshift( $this->curItem, $elm );
 819                 }
 820         }
 821
 822         /**
 823          * Start an element when in MODE_QDESC.
 824          * This generally happens when a simple element has an inner
 825          * rdf:Description to hold qualifier elements.
 826          *
 827          * For example in:
 828          * <exif:DigitalZoomRatio><rdf:Description><rdf:value>0/10</rdf:value>
 829          *   <foo:someQualifier>Bar</foo:someQualifier> </rdf:Description>
 830          *   </exif:DigitalZoomRatio>
 831          * Called when processing the <rdf:value> or <foo:someQualifier>.
 832          *
 833          * @param string $elm Namespace and tag name separated by a space.
 834          *
 835          */
 836         private function startElementModeQDesc( $elm ) {
 837                 if ( $elm === self::NS_RDF . ' value' ) {
 838                         return; // do nothing
 839                 } else {
 840                         // otherwise its a qualifier, which we ignore
 841                         array_unshift( $this->mode, self::MODE_IGNORE );
 842                         array_unshift( $this->curItem, $elm );
 843                 }
 844         }
 845
 846         /**
 847          * Starting an element when in MODE_INITIAL
 848          * This usually happens when we hit an element inside
 849          * the outer rdf:Description
 850          *
 851          * This is generally where most properties start.
 852          *
 853          * @param string $ns Namespace
 854          * @param string $tag Tag name (without namespace prefix)
 855          * @param array $attribs Array of attributes
 856          * @throws MWException
 857          */
 858         private function startElementModeInitial( $ns, $tag, $attribs ) {
 859                 if ( $ns !== self::NS_RDF ) {
 860
 861                         if ( isset( $this->items[$ns][$tag] ) ) {
 862                                 if ( isset( $this->items[$ns][$tag]['structPart'] ) ) {
 863                                         // If this element is supposed to appear only as
 864                                         // a child of a structure, but appears here (not as
 865                                         // a child of a struct), then something weird is
 866                                         // happening, so ignore this element and its children.
 867
 868                                         wfDebugLog( 'XMP', "Encountered <$ns:$tag> outside"
 869                                                 . " of its expected parent. Ignoring." );
 870
 871                                         array_unshift( $this->mode, self::MODE_IGNORE );
 872                                         array_unshift( $this->curItem, $ns . ' ' . $tag );
 873
 874                                         return;
 875                                 }
 876                                 $mode = $this->items[$ns][$tag]['mode'];
 877                                 array_unshift( $this->mode, $mode );
 878                                 array_unshift( $this->curItem, $ns . ' ' . $tag );
 879                                 if ( $mode === self::MODE_STRUCT ) {
 880                                         $this->ancestorStruct = isset( $this->items[$ns][$tag]['map_name'] )
 881                                                 ? $this->items[$ns][$tag]['map_name'] : $tag;
 882                                 }
 883                                 if ( $this->charContent !== false ) {
 884                                         // Something weird.
 885                                         // Should not happen in valid XMP.
 886                                         throw new MWException( 'tag nested in non-whitespace characters.' );
 887                                 }
 888                         } else {
 889                                 // This element is not on our list of allowed elements so ignore.
 890                                 wfDebugLog( 'XMP', __METHOD__ . " Ignoring unrecognized element <$ns:$tag>." );
 891                                 array_unshift( $this->mode, self::MODE_IGNORE );
 892                                 array_unshift( $this->curItem, $ns . ' ' . $tag );
 893
 894                                 return;
 895                         }
 896                 }
 897                 // process attributes
 898                 $this->doAttribs( $attribs );
 899         }
 900
 901         /**
 902          * Hit an opening element when in a Struct (MODE_STRUCT)
 903          * This is generally for fields of a compound property.
 904          *
 905          * Example of a struct (abbreviated; flash has more properties):
 906          *
 907          * <exif:Flash> <rdf:Description> <exif:Fired>True</exif:Fired>
 908          *  <exif:Mode>1</exif:Mode></rdf:Description></exif:Flash>
 909          *
 910          * or:
 911          *
 912          * <exif:Flash rdf:parseType='Resource'> <exif:Fired>True</exif:Fired>
 913          *  <exif:Mode>1</exif:Mode></exif:Flash>
 914          *
 915          * @param string $ns Namespace
 916          * @param string $tag Tag name (no ns)
 917          * @param array $attribs Array of attribs w/ values.
 918          * @throws MWException
 919          */
 920         private function startElementModeStruct( $ns, $tag, $attribs ) {
 921                 if ( $ns !== self::NS_RDF ) {
 922
 923                         if ( isset( $this->items[$ns][$tag] ) ) {
 924                                 if ( isset( $this->items[$ns][$this->ancestorStruct]['children'] )
 925                                         && !isset( $this->items[$ns][$this->ancestorStruct]['children'][$tag] )
 926                                 ) {
 927                                         // This assumes that we don't have inter-namespace nesting
 928                                         // which we don't in all the properties we're interested in.
 929                                         throw new MWException( " <$tag> appeared nested in <" . $this->ancestorStruct
 930                                                 . "> where it is not allowed." );
 931                                 }
 932                                 array_unshift( $this->mode, $this->items[$ns][$tag]['mode'] );
 933                                 array_unshift( $this->curItem, $ns . ' ' . $tag );
 934                                 if ( $this->charContent !== false ) {
 935                                         // Something weird.
 936                                         // Should not happen in valid XMP.
 937                                         throw new MWException( "tag <$tag> nested in non-whitespace characters (" .
 938                                                 $this->charContent . ")." );
 939                                 }
 940                         } else {
 941                                 array_unshift( $this->mode, self::MODE_IGNORE );
 942                                 array_unshift( $this->curItem, $elm );
 943
 944                                 return;
 945                         }
 946                 }
 947
 948                 if ( $ns === self::NS_RDF && $tag === 'Description' ) {
 949                         $this->doAttribs( $attribs );
 950                         array_unshift( $this->mode, self::MODE_STRUCT );
 951                         array_unshift( $this->curItem, $this->curItem[0] );
 952                 }
 953         }
 954
 955         /**
 956          * opening element in MODE_LI
 957          * process elements of arrays.
 958          *
 959          * Example:
 960          * <exif:ISOSpeedRatings> <rdf:Seq> <rdf:li>64</rdf:li>
 961          *   </rdf:Seq> </exif:ISOSpeedRatings>
 962          * This method is called when we hit the <rdf:li> element.
 963          *
 964          * @param string $elm Namespace . ' ' . tagname
 965          * @param array $attribs Attributes. (needed for BAGSTRUCTS)
 966          * @throws MWException If gets a tag other than <rdf:li>
 967          */
 968         private function startElementModeLi( $elm, $attribs ) {
 969                 if ( ( $elm ) !== self::NS_RDF . ' li' ) {
 970                         throw new MWException( "<rdf:li> expected but got $elm." );
 971                 }
 972
 973                 if ( !isset( $this->mode[1] ) ) {
 974                         // This should never ever ever happen. Checking for it
 975                         // to be paranoid.
 976                         throw new MWException( 'In mode Li, but no 2xPrevious mode!' );
 977                 }
 978
 979                 if ( $this->mode[1] === self::MODE_BAGSTRUCT ) {
 980                         // This list item contains a compound (STRUCT) value.
 981                         array_unshift( $this->mode, self::MODE_STRUCT );
 982                         array_unshift( $this->curItem, $elm );
 983                         $this->processingArray = true;
 984
 985                         if ( !isset( $this->curItem[1] ) ) {
 986                                 // be paranoid.
 987                                 throw new MWException( 'Can not find parent of BAGSTRUCT.' );
 988                         }
 989                         list( $curNS, $curTag ) = explode( ' ', $this->curItem[1] );
 990                         $this->ancestorStruct = isset( $this->items[$curNS][$curTag]['map_name'] )
 991                                 ? $this->items[$curNS][$curTag]['map_name'] : $curTag;
 992
 993                         $this->doAttribs( $attribs );
 994                 } else {
 995                         // Normal BAG or SEQ containing simple values.
 996                         array_unshift( $this->mode, self::MODE_SIMPLE );
 997                         // need to add curItem[0] on again since one is for the specific item
 998                         // and one is for the entire group.
 999                         array_unshift( $this->curItem, $this->curItem[0] );
1000                         $this->processingArray = true;
1001                 }
1002         }
1003
1004         /**
1005          * Opening element in MODE_LI_LANG.
1006          * process elements of language alternatives
1007          *
1008          * Example:
1009          * <dc:title> <rdf:Alt> <rdf:li xml:lang="x-default">My house
1010          *  </rdf:li> </rdf:Alt> </dc:title>
1011          *
1012          * This method is called when we hit the <rdf:li> element.
1013          *
1014          * @param string $elm Namespace . ' ' . tag
1015          * @param array $attribs Array of elements (most importantly xml:lang)
1016          * @throws MWException If gets a tag other than <rdf:li> or if no xml:lang
1017          */
1018         private function startElementModeLiLang( $elm, $attribs ) {
1019                 if ( $elm !== self::NS_RDF . ' li' ) {
1020                         throw new MWException( __METHOD__ . " <rdf:li> expected but got $elm." );
1021                 }
1022                 if ( !isset( $attribs[self::NS_XML . ' lang'] )
1023                         || !preg_match( '/^[-A-Za-z0-9]{2,}$/D', $attribs[self::NS_XML . ' lang'] )
1024                 ) {
1025                         throw new MWException( __METHOD__
1026                                 . " <rdf:li> did not contain, or has invalid xml:lang attribute in lang alternative" );
1027                 }
1028
1029                 // Lang is case-insensitive.
1030                 $this->itemLang = strtolower( $attribs[self::NS_XML . ' lang'] );
1031
1032                 // need to add curItem[0] on again since one is for the specific item
1033                 // and one is for the entire group.
1034                 array_unshift( $this->curItem, $this->curItem[0] );
1035                 array_unshift( $this->mode, self::MODE_SIMPLE );
1036                 $this->processingArray = true;
1037         }
1038
1039         /**
1040          * Hits an opening element.
1041          * Generally just calls a helper based on what MODE we're in.
1042          * Also does some initial set up for the wrapper element
1043          *
1044          * @param XMLParser $parser
1045          * @param string $elm Namespace "<space>" element
1046          * @param array $attribs Attribute name => value
1047          * @throws MWException
1048          */
1049         function startElement( $parser, $elm, $attribs ) {
1050
1051                 if ( $elm === self::NS_RDF . ' RDF'
1052                         || $elm === 'adobe:ns:meta/ xmpmeta'
1053                         || $elm === 'adobe:ns:meta/ xapmeta'
1054                 ) {
1055                         /* ignore. */
1056                         return;
1057                 } elseif ( $elm === self::NS_RDF . ' Description' ) {
1058                         if ( count( $this->mode ) === 0 ) {
1059                                 // outer rdf:desc
1060                                 array_unshift( $this->mode, self::MODE_INITIAL );
1061                         }
1062                 } elseif ( $elm === self::NS_RDF . ' type' ) {
1063                         // This doesn't support rdf:type properly.
1064                         // In practise I have yet to see a file that
1065                         // uses this element, however it is mentioned
1066                         // on page 25 of part 1 of the xmp standard.
1067                         //
1068                         // also it seems as if exiv2 and exiftool do not support
1069                         // this either (That or I misunderstand the standard)
1070                         wfDebugLog( 'XMP', __METHOD__ . ' Encountered <rdf:type> which isn\'t currently supported' );
1071                 }
1072
1073                 if ( strpos( $elm, ' ' ) === false ) {
1074                         // This probably shouldn't happen.
1075                         wfDebugLog( 'XMP', __METHOD__ . " Encountered <$elm> which has no namespace. Skipping." );
1076
1077                         return;
1078                 }
1079
1080                 list( $ns, $tag ) = explode( ' ', $elm, 2 );
1081
1082                 if ( count( $this->mode ) === 0 ) {
1083                         // This should not happen.
1084                         throw new MWException( 'Error extracting XMP, '
1085                                 . "encountered <$elm> with no mode" );
1086                 }
1087
1088                 switch ( $this->mode[0] ) {
1089                         case self::MODE_IGNORE:
1090                                 $this->startElementModeIgnore( $elm );
1091                                 break;
1092                         case self::MODE_SIMPLE:
1093                                 $this->startElementModeSimple( $elm, $attribs );
1094                                 break;
1095                         case self::MODE_INITIAL:
1096                                 $this->startElementModeInitial( $ns, $tag, $attribs );
1097                                 break;
1098                         case self::MODE_STRUCT:
1099                                 $this->startElementModeStruct( $ns, $tag, $attribs );
1100                                 break;
1101                         case self::MODE_BAG:
1102                         case self::MODE_BAGSTRUCT:
1103                                 $this->startElementModeBag( $elm );
1104                                 break;
1105                         case self::MODE_SEQ:
1106                                 $this->startElementModeSeq( $elm );
1107                                 break;
1108                         case self::MODE_LANG:
1109                                 $this->startElementModeLang( $elm );
1110                                 break;
1111                         case self::MODE_LI_LANG:
1112                                 $this->startElementModeLiLang( $elm, $attribs );
1113                                 break;
1114                         case self::MODE_LI:
1115                                 $this->startElementModeLi( $elm, $attribs );
1116                                 break;
1117                         case self::MODE_QDESC:
1118                                 $this->startElementModeQDesc( $elm );
1119                                 break;
1120                         default:
1121                                 throw new MWException( 'StartElement in unknown mode: ' . $this->mode[0] );
1122                 }
1123         }
1124
1125         /**
1126          * Process attributes.
1127          * Simple values can be stored as either a tag or attribute
1128          *
1129          * Often the initial "<rdf:Description>" tag just has all the simple
1130          * properties as attributes.
1131          *
1132          * @codingStandardsIgnoreStart Long line that cannot be broken
1133          * @par Example:
1134          * @code
1135          * <rdf:Description rdf:about="" xmlns:exif="http://ns.adobe.com/exif/1.0/" exif:DigitalZoomRatio="0/10">
1136          * @endcode
1137          * @codingStandardsIgnoreEnd
1138          *
1139          * @param array $attribs Array attribute=>value
1140          * @throws MWException
1141          */
1142         private function doAttribs( $attribs ) {
1143                 // first check for rdf:parseType attribute, as that can change
1144                 // how the attributes are interperted.
1145
1146                 if ( isset( $attribs[self::NS_RDF . ' parseType'] )
1147                         && $attribs[self::NS_RDF . ' parseType'] === 'Resource'
1148                         && $this->mode[0] === self::MODE_SIMPLE
1149                 ) {
1150                         // this is equivalent to having an inner rdf:Description
1151                         $this->mode[0] = self::MODE_QDESC;
1152                 }
1153                 foreach ( $attribs as $name => $val ) {
1154                         if ( strpos( $name, ' ' ) === false ) {
1155                                 // This shouldn't happen, but so far some old software forgets namespace
1156                                 // on rdf:about.
1157                                 wfDebugLog( 'XMP', __METHOD__ . ' Encountered non-namespaced attribute: '
1158                                         . " $name=\"$val\". Skipping. " );
1159                                 continue;
1160                         }
1161                         list( $ns, $tag ) = explode( ' ', $name, 2 );
1162                         if ( $ns === self::NS_RDF ) {
1163                                 if ( $tag === 'value' || $tag === 'resource' ) {
1164                                         // resource is for url.
1165                                         // value attribute is a weird way of just putting the contents.
1166                                         $this->char( $this->xmlParser, $val );
1167                                 }
1168                         } elseif ( isset( $this->items[$ns][$tag] ) ) {
1169                                 if ( $this->mode[0] === self::MODE_SIMPLE ) {
1170                                         throw new MWException( __METHOD__
1171                                                 . " $ns:$tag found as attribute where not allowed" );
1172                                 }
1173                                 $this->saveValue( $ns, $tag, $val );
1174                         } else {
1175                                 wfDebugLog( 'XMP', __METHOD__ . " Ignoring unrecognized element <$ns:$tag>." );
1176                         }
1177                 }
1178         }
1179
1180         /**
1181          * Given an extracted value, save it to results array
1182          *
1183          * note also uses $this->ancestorStruct and
1184          * $this->processingArray to determine what name to
1185          * save the value under. (in addition to $tag).
1186          *
1187          * @param string $ns Namespace of tag this is for
1188          * @param string $tag Tag name
1189          * @param string $val Value to save
1190          */
1191         private function saveValue( $ns, $tag, $val ) {
1192
1193                 $info =& $this->items[$ns][$tag];
1194                 $finalName = isset( $info['map_name'] )
1195                         ? $info['map_name'] : $tag;
1196                 if ( isset( $info['validate'] ) ) {
1197                         $validate = is_array( $info['validate'] ) ? $info['validate']
1198                                 : array( 'XMPValidate', $info['validate'] );
1199
1200                         if ( is_callable( $validate ) ) {
1201                                 call_user_func_array( $validate, array( $info, &$val, true ) );
1202                                 // the reasoning behind using &$val instead of using the return value
1203                                 // is to be consistent between here and validating structures.
1204                                 if ( is_null( $val ) ) {
1205                                         wfDebugLog( 'XMP', __METHOD__ . " <$ns:$tag> failed validation." );
1206
1207                                         return;
1208                                 }
1209                         } else {
1210                                 wfDebugLog( 'XMP', __METHOD__ . " Validation function for $finalName ("
1211                                         . $validate[0] . '::' . $validate[1] . '()) is not callable.' );
1212                         }
1213                 }
1214
1215                 if ( $this->ancestorStruct && $this->processingArray ) {
1216                         // Aka both an array and a struct. ( self::MODE_BAGSTRUCT )
1217                         $this->results['xmp-' . $info['map_group']][$this->ancestorStruct][][$finalName] = $val;
1218                 } elseif ( $this->ancestorStruct ) {
1219                         $this->results['xmp-' . $info['map_group']][$this->ancestorStruct][$finalName] = $val;
1220                 } elseif ( $this->processingArray ) {
1221                         if ( $this->itemLang === false ) {
1222                                 // normal array
1223                                 $this->results['xmp-' . $info['map_group']][$finalName][] = $val;
1224                         } else {
1225                                 // lang array.
1226                                 $this->results['xmp-' . $info['map_group']][$finalName][$this->itemLang] = $val;
1227                         }
1228                 } else {
1229                         $this->results['xmp-' . $info['map_group']][$finalName] = $val;
1230                 }
1231         }
1232 }