includes/Html.php

   1 <?php
   2 /**
   3  * Collection of methods to generate HTML content
   4  *
   5  * Copyright © 2009 Aryeh Gregor
   6  * http://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  */
  25
  26 /**
  27  * This class is a collection of static functions that serve two purposes:
  28  *
  29  * 1) Implement any algorithms specified by HTML5, or other HTML
  30  * specifications, in a convenient and self-contained way.
  31  *
  32  * 2) Allow HTML elements to be conveniently and safely generated, like the
  33  * current Xml class but a) less confused (Xml supports HTML-specific things,
  34  * but only sometimes!) and b) not necessarily confined to XML-compatible
  35  * output.
  36  *
  37  * There are two important configuration options this class uses:
  38  *
  39  * $wgMimeType: If this is set to an xml MIME type then output should be
  40  *     valid XHTML5.
  41  * $wgWellFormedXml: If this is set to true, then all output should be
  42  *     well-formed XML (quotes on attributes, self-closing tags, etc.).
  43  *
  44  * This class is meant to be confined to utility functions that are called from
  45  * trusted code paths.  It does not do enforcement of policy like not allowing
  46  * <a> elements.
  47  *
  48  * @since 1.16
  49  */
  50 class Html {
  51         // List of void elements from HTML5, section 8.1.2 as of 2011-08-12
  52         private static $voidElements = array(
  53                 'area',
  54                 'base',
  55                 'br',
  56                 'col',
  57                 'command',
  58                 'embed',
  59                 'hr',
  60                 'img',
  61                 'input',
  62                 'keygen',
  63                 'link',
  64                 'meta',
  65                 'param',
  66                 'source',
  67                 'track',
  68                 'wbr',
  69         );
  70
  71         // Boolean attributes, which may have the value omitted entirely.  Manually
  72         // collected from the HTML5 spec as of 2011-08-12.
  73         private static $boolAttribs = array(
  74                 'async',
  75                 'autofocus',
  76                 'autoplay',
  77                 'checked',
  78                 'controls',
  79                 'default',
  80                 'defer',
  81                 'disabled',
  82                 'formnovalidate',
  83                 'hidden',
  84                 'ismap',
  85                 'itemscope',
  86                 'loop',
  87                 'multiple',
  88                 'muted',
  89                 'novalidate',
  90                 'open',
  91                 'pubdate',
  92                 'readonly',
  93                 'required',
  94                 'reversed',
  95                 'scoped',
  96                 'seamless',
  97                 'selected',
  98                 'truespeed',
  99                 'typemustmatch',
 100                 // HTML5 Microdata
 101                 'itemscope',
 102         );
 103
 104         /**
 105          * Modifies a set of attributes meant for button elements
 106          * and apply a set of default attributes when $wgUseMediaWikiUIEverywhere enabled.
 107          * @param array $modifiers to add to the button
 108          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 109          * @return array $attrs A modified attribute array
 110          */
 111         public static function buttonAttributes( $attrs, $modifiers = array() ) {
 112                 global $wgUseMediaWikiUIEverywhere;
 113                 if ( $wgUseMediaWikiUIEverywhere ) {
 114                         if ( isset( $attrs['class'] ) ) {
 115                                 if ( is_array( $attrs['class'] ) ) {
 116                                         $attrs['class'][] = 'mw-ui-button';
 117                                         $attrs = array_merge( $attrs, $modifiers );
 118                                         // ensure compatibility with Xml
 119                                         $attrs['class'] = implode( ' ', $attrs['class'] );
 120                                 } else {
 121                                         $attrs['class'] .= ' mw-ui-button ' . implode( ' ', $modifiers );
 122                                 }
 123                         } else {
 124                                 $attrs['class'] = array( 'mw-ui-button' );
 125                                 // ensure compatibility with Xml
 126                                 $attrs['class'] = implode( ' ', array_merge( $attrs['class'], $modifiers ) );
 127                         }
 128                 }
 129                 return $attrs;
 130         }
 131
 132         /**
 133          * Modifies a set of attributes meant for text input elements
 134          * and apply a set of default attributes.
 135          * Removes size attribute when $wgUseMediaWikiUIEverywhere enabled.
 136          * @param array $attrs An attribute array.
 137          * @return array $attrs A modified attribute array
 138          */
 139         public static function getTextInputAttributes( $attrs ) {
 140                 global $wgUseMediaWikiUIEverywhere;
 141                 if ( !$attrs ) {
 142                         $attrs = array();
 143                 }
 144                 if ( $wgUseMediaWikiUIEverywhere ) {
 145                         if ( isset( $attrs['class'] ) ) {
 146                                 if ( is_array( $attrs['class'] ) ) {
 147                                         $attrs['class'][] = 'mw-ui-input';
 148                                 } else {
 149                                         $attrs['class'] .= ' mw-ui-input';
 150                                 }
 151                         } else {
 152                                 $attrs['class'] = 'mw-ui-input';
 153                         }
 154                 }
 155                 return $attrs;
 156         }
 157
 158         /**
 159          * Returns an HTML link element in a string styled as a button
 160          * (when $wgUseMediaWikiUIEverywhere is enabled).
 161          *
 162          * @param string $contents The raw HTML contents of the element: *not*
 163          *   escaped!
 164          * @param array $attrs Associative array of attributes, e.g., array(
 165          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 166          *   further documentation.
 167          * @param array $modifiers to add to the button
 168          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 169          * @return string Raw HTML
 170          */
 171         public static function linkButton( $contents, $attrs, $modifiers = array() ) {
 172                 return Html::element( 'a',
 173                         self::buttonAttributes( $attrs, $modifiers ),
 174                         $contents
 175                 );
 176         }
 177
 178         /**
 179          * Returns an HTML link element in a string styled as a button
 180          * (when $wgUseMediaWikiUIEverywhere is enabled).
 181          *
 182          * @param string $contents The raw HTML contents of the element: *not*
 183          *   escaped!
 184          * @param array $attrs Associative array of attributes, e.g., array(
 185          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 186          *   further documentation.
 187          * @param array $modifiers to add to the button
 188          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 189          * @return string Raw HTML
 190          */
 191         public static function submitButton( $contents, $attrs, $modifiers = array() ) {
 192                 $attrs['type'] = 'submit';
 193                 $attrs['value'] = $contents;
 194                 return Html::element( 'input', self::buttonAttributes( $attrs, $modifiers ) );
 195         }
 196
 197         /**
 198          * Returns an HTML element in a string.  The major advantage here over
 199          * manually typing out the HTML is that it will escape all attribute
 200          * values.
 201          *
 202          * This is quite similar to Xml::tags(), but it implements some useful
 203          * HTML-specific logic.  For instance, there is no $allowShortTag
 204          * parameter: the closing tag is magically omitted if $element has an empty
 205          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 206          * shaved off the HTML output as well.
 207          *
 208          * @param string $element The element's name, e.g., 'a'
 209          * @param array $attribs Associative array of attributes, e.g., array(
 210          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 211          *   further documentation.
 212          * @param string $contents The raw HTML contents of the element: *not*
 213          *   escaped!
 214          * @return string Raw HTML
 215          */
 216         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 217                 global $wgWellFormedXml;
 218                 $start = self::openElement( $element, $attribs );
 219                 if ( in_array( $element, self::$voidElements ) ) {
 220                         if ( $wgWellFormedXml ) {
 221                                 // Silly XML.
 222                                 return substr( $start, 0, -1 ) . ' />';
 223                         }
 224                         return $start;
 225                 } else {
 226                         return "$start$contents" . self::closeElement( $element );
 227                 }
 228         }
 229
 230         /**
 231          * Identical to rawElement(), but HTML-escapes $contents (like
 232          * Xml::element()).
 233          *
 234          * @param string $element
 235          * @param array $attribs
 236          * @param string $contents
 237          *
 238          * @return string
 239          */
 240         public static function element( $element, $attribs = array(), $contents = '' ) {
 241                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 242                         // There's no point in escaping quotes, >, etc. in the contents of
 243                         // elements.
 244                         '&' => '&amp;',
 245                         '<' => '&lt;'
 246                 ) ) );
 247         }
 248
 249         /**
 250          * Identical to rawElement(), but has no third parameter and omits the end
 251          * tag (and the self-closing '/' in XML mode for empty elements).
 252          *
 253          * @param string $element
 254          * @param array $attribs
 255          *
 256          * @return string
 257          */
 258         public static function openElement( $element, $attribs = array() ) {
 259                 $attribs = (array)$attribs;
 260                 // This is not required in HTML5, but let's do it anyway, for
 261                 // consistency and better compression.
 262                 $element = strtolower( $element );
 263
 264                 // Remove invalid input types
 265                 if ( $element == 'input' ) {
 266                         $validTypes = array(
 267                                 'hidden',
 268                                 'text',
 269                                 'password',
 270                                 'checkbox',
 271                                 'radio',
 272                                 'file',
 273                                 'submit',
 274                                 'image',
 275                                 'reset',
 276                                 'button',
 277
 278                                 // HTML input types
 279                                 'datetime',
 280                                 'datetime-local',
 281                                 'date',
 282                                 'month',
 283                                 'time',
 284                                 'week',
 285                                 'number',
 286                                 'range',
 287                                 'email',
 288                                 'url',
 289                                 'search',
 290                                 'tel',
 291                                 'color',
 292                         );
 293                         if ( isset( $attribs['type'] ) && !in_array( $attribs['type'], $validTypes ) ) {
 294                                 unset( $attribs['type'] );
 295                         }
 296                 }
 297
 298                 // According to standard the default type for <button> elements is "submit".
 299                 // Depending on compatibility mode IE might use "button", instead.
 300                 // We enforce the standard "submit".
 301                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 302                         $attribs['type'] = 'submit';
 303                 }
 304
 305                 return "<$element" . self::expandAttributes(
 306                         self::dropDefaults( $element, $attribs ) ) . '>';
 307         }
 308
 309         /**
 310          * Returns "</$element>"
 311          *
 312          * @since 1.17
 313          * @param string $element Name of the element, e.g., 'a'
 314          * @return string A closing tag
 315          */
 316         public static function closeElement( $element ) {
 317                 $element = strtolower( $element );
 318
 319                 return "</$element>";
 320         }
 321
 322         /**
 323          * Given an element name and an associative array of element attributes,
 324          * return an array that is functionally identical to the input array, but
 325          * possibly smaller.  In particular, attributes might be stripped if they
 326          * are given their default values.
 327          *
 328          * This method is not guaranteed to remove all redundant attributes, only
 329          * some common ones and some others selected arbitrarily at random.  It
 330          * only guarantees that the output array should be functionally identical
 331          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 332          *
 333          * @param string $element Name of the element, e.g., 'a'
 334          * @param array $attribs Associative array of attributes, e.g., array(
 335          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 336          *   further documentation.
 337          * @return array An array of attributes functionally identical to $attribs
 338          */
 339         private static function dropDefaults( $element, $attribs ) {
 340
 341                 // Whenever altering this array, please provide a covering test case
 342                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 343                 static $attribDefaults = array(
 344                         'area' => array( 'shape' => 'rect' ),
 345                         'button' => array(
 346                                 'formaction' => 'GET',
 347                                 'formenctype' => 'application/x-www-form-urlencoded',
 348                         ),
 349                         'canvas' => array(
 350                                 'height' => '150',
 351                                 'width' => '300',
 352                         ),
 353                         'command' => array( 'type' => 'command' ),
 354                         'form' => array(
 355                                 'action' => 'GET',
 356                                 'autocomplete' => 'on',
 357                                 'enctype' => 'application/x-www-form-urlencoded',
 358                         ),
 359                         'input' => array(
 360                                 'formaction' => 'GET',
 361                                 'type' => 'text',
 362                         ),
 363                         'keygen' => array( 'keytype' => 'rsa' ),
 364                         'link' => array( 'media' => 'all' ),
 365                         'menu' => array( 'type' => 'list' ),
 366                         // Note: the use of text/javascript here instead of other JavaScript
 367                         // MIME types follows the HTML5 spec.
 368                         'script' => array( 'type' => 'text/javascript' ),
 369                         'style' => array(
 370                                 'media' => 'all',
 371                                 'type' => 'text/css',
 372                         ),
 373                         'textarea' => array( 'wrap' => 'soft' ),
 374                 );
 375
 376                 $element = strtolower( $element );
 377
 378                 foreach ( $attribs as $attrib => $value ) {
 379                         $lcattrib = strtolower( $attrib );
 380                         if ( is_array( $value ) ) {
 381                                 $value = implode( ' ', $value );
 382                         } else {
 383                                 $value = strval( $value );
 384                         }
 385
 386                         // Simple checks using $attribDefaults
 387                         if ( isset( $attribDefaults[$element][$lcattrib] )
 388                                 && $attribDefaults[$element][$lcattrib] == $value
 389                         ) {
 390                                 unset( $attribs[$attrib] );
 391                         }
 392
 393                         if ( $lcattrib == 'class' && $value == '' ) {
 394                                 unset( $attribs[$attrib] );
 395                         }
 396                 }
 397
 398                 // More subtle checks
 399                 if ( $element === 'link'
 400                         && isset( $attribs['type'] ) && strval( $attribs['type'] ) == 'text/css'
 401                 ) {
 402                         unset( $attribs['type'] );
 403                 }
 404                 if ( $element === 'input' ) {
 405                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 406                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 407                         if ( $type === 'checkbox' || $type === 'radio' ) {
 408                                 // The default value for checkboxes and radio buttons is 'on'
 409                                 // not ''. By stripping value="" we break radio boxes that
 410                                 // actually wants empty values.
 411                                 if ( $value === 'on' ) {
 412                                         unset( $attribs['value'] );
 413                                 }
 414                         } elseif ( $type === 'submit' ) {
 415                                 // The default value for submit appears to be "Submit" but
 416                                 // let's not bother stripping out localized text that matches
 417                                 // that.
 418                         } else {
 419                                 // The default value for nearly every other field type is ''
 420                                 // The 'range' and 'color' types use different defaults but
 421                                 // stripping a value="" does not hurt them.
 422                                 if ( $value === '' ) {
 423                                         unset( $attribs['value'] );
 424                                 }
 425                         }
 426                 }
 427                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 428                         if ( in_array( 'multiple', $attribs )
 429                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 430                         ) {
 431                                 // A multi-select
 432                                 if ( strval( $attribs['size'] ) == '4' ) {
 433                                         unset( $attribs['size'] );
 434                                 }
 435                         } else {
 436                                 // Single select
 437                                 if ( strval( $attribs['size'] ) == '1' ) {
 438                                         unset( $attribs['size'] );
 439                                 }
 440                         }
 441                 }
 442
 443                 return $attribs;
 444         }
 445
 446         /**
 447          * Given an associative array of element attributes, generate a string
 448          * to stick after the element name in HTML output.  Like array( 'href' =>
 449          * 'http://www.mediawiki.org/' ) becomes something like
 450          * ' href="http://www.mediawiki.org"'.  Again, this is like
 451          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 452          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 453          * and will treat boolean attributes specially.
 454          *
 455          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 456          * values are allowed as well, which will automagically be normalized
 457          * and converted to a space-separated string. In addition to a numerical
 458          * array, the attribute value may also be an associative array. See the
 459          * example below for how that works.
 460          *
 461          * @par Numerical array
 462          * @code
 463          *     Html::element( 'em', array(
 464          *         'class' => array( 'foo', 'bar' )
 465          *     ) );
 466          *     // gives '<em class="foo bar"></em>'
 467          * @endcode
 468          *
 469          * @par Associative array
 470          * @code
 471          *     Html::element( 'em', array(
 472          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 473          *     ) );
 474          *     // gives '<em class="bar quux"></em>'
 475          * @endcode
 476          *
 477          * @param array $attribs Associative array of attributes, e.g., array(
 478          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 479          *   A value of false means to omit the attribute.  For boolean attributes,
 480          *   you can omit the key, e.g., array( 'checked' ) instead of
 481          *   array( 'checked' => 'checked' ) or such.
 482          *
 483          * @throws MWException If an attribute that doesn't allow lists is set to an array
 484          * @return string HTML fragment that goes between element name and '>'
 485          *   (starting with a space if at least one attribute is output)
 486          */
 487         public static function expandAttributes( $attribs ) {
 488                 global $wgWellFormedXml;
 489
 490                 $ret = '';
 491                 $attribs = (array)$attribs;
 492                 foreach ( $attribs as $key => $value ) {
 493                         // Support intuitive array( 'checked' => true/false ) form
 494                         if ( $value === false || is_null( $value ) ) {
 495                                 continue;
 496                         }
 497
 498                         // For boolean attributes, support array( 'foo' ) instead of
 499                         // requiring array( 'foo' => 'meaningless' ).
 500                         if ( is_int( $key ) && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 501                                 $key = $value;
 502                         }
 503
 504                         // Not technically required in HTML5 but we'd like consistency
 505                         // and better compression anyway.
 506                         $key = strtolower( $key );
 507
 508                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 509                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 510                         // without telling the user why, which is much worse than failing
 511                         // server-side validation.  Opera is the only other implementation at
 512                         // this time, and has ugly UI, so just kill the feature entirely until
 513                         // we have at least one good implementation.
 514
 515                         // As the default value of "1" for "step" rejects decimal
 516                         // numbers to be entered in 'type="number"' fields, allow
 517                         // the special case 'step="any"'.
 518
 519                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) )
 520                                 || $key === 'step' && $value !== 'any' ) {
 521                                 continue;
 522                         }
 523
 524                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 525                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 526                         $spaceSeparatedListAttributes = array(
 527                                 'class', // html4, html5
 528                                 'accesskey', // as of html5, multiple space-separated values allowed
 529                                 // html4-spec doesn't document rel= as space-separated
 530                                 // but has been used like that and is now documented as such
 531                                 // in the html5-spec.
 532                                 'rel',
 533                         );
 534
 535                         // Specific features for attributes that allow a list of space-separated values
 536                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 537                                 // Apply some normalization and remove duplicates
 538
 539                                 // Convert into correct array. Array can contain space-separated
 540                                 // values. Implode/explode to get those into the main array as well.
 541                                 if ( is_array( $value ) ) {
 542                                         // If input wasn't an array, we can skip this step
 543                                         $newValue = array();
 544                                         foreach ( $value as $k => $v ) {
 545                                                 if ( is_string( $v ) ) {
 546                                                         // String values should be normal `array( 'foo' )`
 547                                                         // Just append them
 548                                                         if ( !isset( $value[$v] ) ) {
 549                                                                 // As a special case don't set 'foo' if a
 550                                                                 // separate 'foo' => true/false exists in the array
 551                                                                 // keys should be authoritative
 552                                                                 $newValue[] = $v;
 553                                                         }
 554                                                 } elseif ( $v ) {
 555                                                         // If the value is truthy but not a string this is likely
 556                                                         // an array( 'foo' => true ), falsy values don't add strings
 557                                                         $newValue[] = $k;
 558                                                 }
 559                                         }
 560                                         $value = implode( ' ', $newValue );
 561                                 }
 562                                 $value = explode( ' ', $value );
 563
 564                                 // Normalize spacing by fixing up cases where people used
 565                                 // more than 1 space and/or a trailing/leading space
 566                                 $value = array_diff( $value, array( '', ' ' ) );
 567
 568                                 // Remove duplicates and create the string
 569                                 $value = implode( ' ', array_unique( $value ) );
 570                         } elseif ( is_array( $value ) ) {
 571                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 572                         }
 573
 574                         // See the "Attributes" section in the HTML syntax part of HTML5,
 575                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 576                         // marks omitted, but not all.  (Although a literal " is not
 577                         // permitted, we don't check for that, since it will be escaped
 578                         // anyway.)
 579
 580                         // See also research done on further characters that need to be
 581                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 582                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 583                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 584                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 585                         if ( $wgWellFormedXml || $value === '' || preg_match( "![$badChars]!u", $value ) ) {
 586                                 $quote = '"';
 587                         } else {
 588                                 $quote = '';
 589                         }
 590
 591                         if ( in_array( $key, self::$boolAttribs ) ) {
 592                                 // In HTML5, we can leave the value empty. If we don't need
 593                                 // well-formed XML, we can omit the = entirely.
 594                                 if ( !$wgWellFormedXml ) {
 595                                         $ret .= " $key";
 596                                 } else {
 597                                         $ret .= " $key=\"\"";
 598                                 }
 599                         } else {
 600                                 // Apparently we need to entity-encode \n, \r, \t, although the
 601                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 602                                 // and we don't need <> escaped here, we may as well not call
 603                                 // htmlspecialchars().
 604                                 // @todo FIXME: Verify that we actually need to
 605                                 // escape \n\r\t here, and explain why, exactly.
 606                                 #
 607                                 // We could call Sanitizer::encodeAttribute() for this, but we
 608                                 // don't because we're stubborn and like our marginal savings on
 609                                 // byte size from not having to encode unnecessary quotes.
 610                                 $map = array(
 611                                         '&' => '&amp;',
 612                                         '"' => '&quot;',
 613                                         "\n" => '&#10;',
 614                                         "\r" => '&#13;',
 615                                         "\t" => '&#9;'
 616                                 );
 617                                 if ( $wgWellFormedXml ) {
 618                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 619                                         // But reportedly it breaks some XML tools?
 620                                         // @todo FIXME: Is this really true?
 621                                         $map['<'] = '&lt;';
 622                                 }
 623                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 624                         }
 625                 }
 626                 return $ret;
 627         }
 628
 629         /**
 630          * Output a "<script>" tag with the given contents.
 631          *
 632          * @todo do some useful escaping as well, like if $contents contains
 633          * literal "</script>" or (for XML) literal "]]>".
 634          *
 635          * @param string $contents JavaScript
 636          * @return string Raw HTML
 637          */
 638         public static function inlineScript( $contents ) {
 639                 global $wgWellFormedXml;
 640
 641                 $attrs = array();
 642
 643                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 644                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 645                 }
 646
 647                 return self::rawElement( 'script', $attrs, $contents );
 648         }
 649
 650         /**
 651          * Output a "<script>" tag linking to the given URL, e.g.,
 652          * "<script src=foo.js></script>".
 653          *
 654          * @param string $url
 655          * @return string Raw HTML
 656          */
 657         public static function linkedScript( $url ) {
 658                 $attrs = array( 'src' => $url );
 659
 660                 return self::element( 'script', $attrs );
 661         }
 662
 663         /**
 664          * Output a "<style>" tag with the given contents for the given media type
 665          * (if any).  TODO: do some useful escaping as well, like if $contents
 666          * contains literal "</style>" (admittedly unlikely).
 667          *
 668          * @param string $contents CSS
 669          * @param string $media A media type string, like 'screen'
 670          * @return string Raw HTML
 671          */
 672         public static function inlineStyle( $contents, $media = 'all' ) {
 673                 global $wgWellFormedXml;
 674
 675                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 676                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 677                 }
 678
 679                 return self::rawElement( 'style', array(
 680                         'type' => 'text/css',
 681                         'media' => $media,
 682                 ), $contents );
 683         }
 684
 685         /**
 686          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 687          * media type (if any).
 688          *
 689          * @param string $url
 690          * @param string $media A media type string, like 'screen'
 691          * @return string Raw HTML
 692          */
 693         public static function linkedStyle( $url, $media = 'all' ) {
 694                 return self::element( 'link', array(
 695                         'rel' => 'stylesheet',
 696                         'href' => $url,
 697                         'type' => 'text/css',
 698                         'media' => $media,
 699                 ) );
 700         }
 701
 702         /**
 703          * Convenience function to produce an "<input>" element.  This supports the
 704          * new HTML5 input types and attributes.
 705          *
 706          * @param string $name Name attribute
 707          * @param array $value Value attribute
 708          * @param string $type Type attribute
 709          * @param array $attribs Associative array of miscellaneous extra
 710          *   attributes, passed to Html::element()
 711          * @return string Raw HTML
 712          */
 713         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 714                 $attribs['type'] = $type;
 715                 $attribs['value'] = $value;
 716                 $attribs['name'] = $name;
 717                 if ( in_array( $type, array( 'text', 'search', 'email', 'password', 'number' ) ) ) {
 718                         $attribs = Html::getTextInputAttributes( $attribs );
 719                 }
 720                 return self::element( 'input', $attribs );
 721         }
 722
 723         /**
 724          * Convenience function to produce a checkbox (input element with type=checkbox)
 725          *
 726          * @param string $name Name attribute
 727          * @param bool $checked Whether the checkbox is checked or not
 728          * @param array $attribs Array of additional attributes
 729          * @return string
 730          */
 731         public static function check( $name, $checked = false, array $attribs = array() ) {
 732                 if ( isset( $attribs['value'] ) ) {
 733                         $value = $attribs['value'];
 734                         unset( $attribs['value'] );
 735                 } else {
 736                         $value = 1;
 737                 }
 738
 739                 if ( $checked ) {
 740                         $attribs[] = 'checked';
 741                 }
 742
 743                 return self::input( $name, $value, 'checkbox', $attribs );
 744         }
 745
 746         /**
 747          * Convenience function to produce a checkbox (input element with type=checkbox)
 748          *
 749          * @param string $name Name attribute
 750          * @param bool $checked Whether the checkbox is checked or not
 751          * @param array $attribs Array of additional attributes
 752          * @return string
 753          */
 754         public static function radio( $name, $checked = false, array $attribs = array() ) {
 755                 if ( isset( $attribs['value'] ) ) {
 756                         $value = $attribs['value'];
 757                         unset( $attribs['value'] );
 758                 } else {
 759                         $value = 1;
 760                 }
 761
 762                 if ( $checked ) {
 763                         $attribs[] = 'checked';
 764                 }
 765
 766                 return self::input( $name, $value, 'radio', $attribs );
 767         }
 768
 769         /**
 770          * Convenience function for generating a label for inputs.
 771          *
 772          * @param string $label Contents of the label
 773          * @param string $id ID of the element being labeled
 774          * @param array $attribs Additional attributes
 775          * @return string
 776          */
 777         public static function label( $label, $id, array $attribs = array() ) {
 778                 $attribs += array(
 779                         'for' => $id
 780                 );
 781                 return self::element( 'label', $attribs, $label );
 782         }
 783
 784         /**
 785          * Convenience function to produce an input element with type=hidden
 786          *
 787          * @param string $name Name attribute
 788          * @param string $value Value attribute
 789          * @param array $attribs Associative array of miscellaneous extra
 790          *   attributes, passed to Html::element()
 791          * @return string Raw HTML
 792          */
 793         public static function hidden( $name, $value, $attribs = array() ) {
 794                 return self::input( $name, $value, 'hidden', $attribs );
 795         }
 796
 797         /**
 798          * Convenience function to produce a <textarea> element.
 799          *
 800          * This supports leaving out the cols= and rows= which Xml requires and are
 801          * required by HTML4/XHTML but not required by HTML5.
 802          *
 803          * @param string $name Name attribute
 804          * @param string $value Value attribute
 805          * @param array $attribs Associative array of miscellaneous extra
 806          *   attributes, passed to Html::element()
 807          * @return string Raw HTML
 808          */
 809         public static function textarea( $name, $value = '', $attribs = array() ) {
 810                 $attribs['name'] = $name;
 811
 812                 if ( substr( $value, 0, 1 ) == "\n" ) {
 813                         // Workaround for bug 12130: browsers eat the initial newline
 814                         // assuming that it's just for show, but they do keep the later
 815                         // newlines, which we may want to preserve during editing.
 816                         // Prepending a single newline
 817                         $spacedValue = "\n" . $value;
 818                 } else {
 819                         $spacedValue = $value;
 820                 }
 821                 return self::element( 'textarea', Html::getTextInputAttributes( $attribs ), $spacedValue );
 822         }
 823
 824         /**
 825          * Build a drop-down box for selecting a namespace
 826          *
 827          * @param array $params Params to set.
 828          * - selected: [optional] Id of namespace which should be pre-selected
 829          * - all: [optional] Value of item for "all namespaces". If null or unset,
 830          *   no "<option>" is generated to select all namespaces.
 831          * - label: text for label to add before the field.
 832          * - exclude: [optional] Array of namespace ids to exclude.
 833          * - disable: [optional] Array of namespace ids for which the option should
 834          *   be disabled in the selector.
 835          * @param array $selectAttribs HTML attributes for the generated select element.
 836          * - id:   [optional], default: 'namespace'.
 837          * - name: [optional], default: 'namespace'.
 838          * @return string HTML code to select a namespace.
 839          */
 840         public static function namespaceSelector( array $params = array(),
 841                 array $selectAttribs = array()
 842         ) {
 843                 global $wgContLang;
 844
 845                 ksort( $selectAttribs );
 846
 847                 // Is a namespace selected?
 848                 if ( isset( $params['selected'] ) ) {
 849                         // If string only contains digits, convert to clean int. Selected could also
 850                         // be "all" or "" etc. which needs to be left untouched.
 851                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 852                         // and returns false for already clean ints. Use regex instead..
 853                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 854                                 $params['selected'] = intval( $params['selected'] );
 855                         }
 856                         // else: leaves it untouched for later processing
 857                 } else {
 858                         $params['selected'] = '';
 859                 }
 860
 861                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 862                         $params['exclude'] = array();
 863                 }
 864                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 865                         $params['disable'] = array();
 866                 }
 867
 868                 // Associative array between option-values and option-labels
 869                 $options = array();
 870
 871                 if ( isset( $params['all'] ) ) {
 872                         // add an option that would let the user select all namespaces.
 873                         // Value is provided by user, the name shown is localized for the user.
 874                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 875                 }
 876                 // Add all namespaces as options (in the content language)
 877                 $options += $wgContLang->getFormattedNamespaces();
 878
 879                 // Convert $options to HTML and filter out namespaces below 0
 880                 $optionsHtml = array();
 881                 foreach ( $options as $nsId => $nsName ) {
 882                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 883                                 continue;
 884                         }
 885                         if ( $nsId === NS_MAIN ) {
 886                                 // For other namespaces use the namespace prefix as label, but for
 887                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 888                                 $nsName = wfMessage( 'blanknamespace' )->text();
 889                         } elseif ( is_int( $nsId ) ) {
 890                                 $nsName = $wgContLang->convertNamespace( $nsId );
 891                         }
 892                         $optionsHtml[] = Html::element(
 893                                 'option', array(
 894                                         'disabled' => in_array( $nsId, $params['disable'] ),
 895                                         'value' => $nsId,
 896                                         'selected' => $nsId === $params['selected'],
 897                                 ), $nsName
 898                         );
 899                 }
 900
 901                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 902                         $selectAttribs['id'] = 'namespace';
 903                 }
 904
 905                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 906                         $selectAttribs['name'] = 'namespace';
 907                 }
 908
 909                 $ret = '';
 910                 if ( isset( $params['label'] ) ) {
 911                         $ret .= Html::element(
 912                                 'label', array(
 913                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 914                                 ), $params['label']
 915                         ) . '&#160;';
 916                 }
 917
 918                 // Wrap options in a <select>
 919                 $ret .= Html::openElement( 'select', $selectAttribs )
 920                         . "\n"
 921                         . implode( "\n", $optionsHtml )
 922                         . "\n"
 923                         . Html::closeElement( 'select' );
 924
 925                 return $ret;
 926         }
 927
 928         /**
 929          * Constructs the opening html-tag with necessary doctypes depending on
 930          * global variables.
 931          *
 932          * @param array $attribs Associative array of miscellaneous extra
 933          *   attributes, passed to Html::element() of html tag.
 934          * @return string Raw HTML
 935          */
 936         public static function htmlHeader( $attribs = array() ) {
 937                 $ret = '';
 938
 939                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 940
 941                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 942
 943                 if ( $isXHTML ) { // XHTML5
 944                         // XML MIME-typed markup should have an xml header.
 945                         // However a DOCTYPE is not needed.
 946                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 947
 948                         // Add the standard xmlns
 949                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 950
 951                         // And support custom namespaces
 952                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 953                                 $attribs["xmlns:$tag"] = $ns;
 954                         }
 955                 } else { // HTML5
 956                         // DOCTYPE
 957                         $ret .= "<!DOCTYPE html>\n";
 958                 }
 959
 960                 if ( $wgHtml5Version ) {
 961                         $attribs['version'] = $wgHtml5Version;
 962                 }
 963
 964                 $html = Html::openElement( 'html', $attribs );
 965
 966                 if ( $html ) {
 967                         $html .= "\n";
 968                 }
 969
 970                 $ret .= $html;
 971
 972                 return $ret;
 973         }
 974
 975         /**
 976          * Determines if the given MIME type is xml.
 977          *
 978          * @param string $mimetype MIME type
 979          * @return bool
 980          */
 981         public static function isXmlMimeType( $mimetype ) {
 982                 # http://www.whatwg.org/html/infrastructure.html#xml-mime-type
 983                 # * text/xml
 984                 # * application/xml
 985                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
 986                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
 987         }
 988
 989         /**
 990          * Get HTML for an info box with an icon.
 991          *
 992          * @param string $text Wikitext, get this with wfMessage()->plain()
 993          * @param string $icon Path to icon file (used as 'src' attribute)
 994          * @param string $alt Alternate text for the icon
 995          * @param string $class Additional class name to add to the wrapper div
 996          *
 997          * @return string
 998          */
 999         static function infoBox( $text, $icon, $alt, $class = false ) {
1000                 $s = Html::openElement( 'div', array( 'class' => "mw-infobox $class" ) );
1001
1002                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ) .
1003                                 Html::element( 'img',
1004                                         array(
1005                                                 'src' => $icon,
1006                                                 'alt' => $alt,
1007                                         )
1008                                 ) .
1009                                 Html::closeElement( 'div' );
1010
1011                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ) .
1012                                 $text .
1013                                 Html::closeElement( 'div' );
1014                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1015
1016                 $s .= Html::closeElement( 'div' );
1017
1018                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1019
1020                 return $s;
1021         }
1022
1023         /**
1024          * Generate a srcset attribute value from an array mapping pixel densities
1025          * to URLs. Note that srcset supports width and height values as well, which
1026          * are not used here.
1027          *
1028          * @param array $urls
1029          * @return string
1030          */
1031         static function srcSet( $urls ) {
1032                 $candidates = array();
1033                 foreach ( $urls as $density => $url ) {
1034                         // Image candidate syntax per current whatwg live spec, 2012-09-23:
1035                         // http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
1036                         $candidates[] = "{$url} {$density}x";
1037                 }
1038                 return implode( ", ", $candidates );
1039         }
1040 }