includes/GlobalFunctions.php

   1 <?php
   2 /**
   3  * Global functions used everywhere.
   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  */
  22
  23 if ( !defined( 'MEDIAWIKI' ) ) {
  24         die( "This file is part of MediaWiki, it is not a valid entry point" );
  25 }
  26
  27 // Hide compatibility functions from Doxygen
  28 /// @cond
  29
  30 /**
  31  * Compatibility functions
  32  *
  33  * We support PHP 5.3.2 and up.
  34  * Re-implementations of newer functions or functions in non-standard
  35  * PHP extensions may be included here.
  36  */
  37
  38 if ( !function_exists( 'iconv' ) ) {
  39         /**
  40          * @codeCoverageIgnore
  41          * @return string
  42          */
  43         function iconv( $from, $to, $string ) {
  44                 return Fallback::iconv( $from, $to, $string );
  45         }
  46 }
  47
  48 if ( !function_exists( 'mb_substr' ) ) {
  49         /**
  50          * @codeCoverageIgnore
  51          * @return string
  52          */
  53         function mb_substr( $str, $start, $count = 'end' ) {
  54                 return Fallback::mb_substr( $str, $start, $count );
  55         }
  56
  57         /**
  58          * @codeCoverageIgnore
  59          * @return int
  60          */
  61         function mb_substr_split_unicode( $str, $splitPos ) {
  62                 return Fallback::mb_substr_split_unicode( $str, $splitPos );
  63         }
  64 }
  65
  66 if ( !function_exists( 'mb_strlen' ) ) {
  67         /**
  68          * @codeCoverageIgnore
  69          * @return int
  70          */
  71         function mb_strlen( $str, $enc = '' ) {
  72                 return Fallback::mb_strlen( $str, $enc );
  73         }
  74 }
  75
  76 if ( !function_exists( 'mb_strpos' ) ) {
  77         /**
  78          * @codeCoverageIgnore
  79          * @return int
  80          */
  81         function mb_strpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  82                 return Fallback::mb_strpos( $haystack, $needle, $offset, $encoding );
  83         }
  84 }
  85
  86 if ( !function_exists( 'mb_strrpos' ) ) {
  87         /**
  88          * @codeCoverageIgnore
  89          * @return int
  90          */
  91         function mb_strrpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  92                 return Fallback::mb_strrpos( $haystack, $needle, $offset, $encoding );
  93         }
  94 }
  95
  96 // gzdecode function only exists in PHP >= 5.4.0
  97 // http://php.net/gzdecode
  98 if ( !function_exists( 'gzdecode' ) ) {
  99         /**
 100          * @codeCoverageIgnore
 101          * @return string
 102          */
 103         function gzdecode( $data ) {
 104                 return gzinflate( substr( $data, 10, -8 ) );
 105         }
 106 }
 107 /// @endcond
 108
 109 /**
 110  * Like array_diff( $a, $b ) except that it works with two-dimensional arrays.
 111  * @param $a array
 112  * @param $b array
 113  * @return array
 114  */
 115 function wfArrayDiff2( $a, $b ) {
 116         return array_udiff( $a, $b, 'wfArrayDiff2_cmp' );
 117 }
 118
 119 /**
 120  * @param $a array|string
 121  * @param $b array|string
 122  * @return int
 123  */
 124 function wfArrayDiff2_cmp( $a, $b ) {
 125         if ( is_string( $a ) && is_string( $b ) ) {
 126                 return strcmp( $a, $b );
 127         } elseif ( count( $a ) !== count( $b ) ) {
 128                 return count( $a ) < count( $b ) ? -1 : 1;
 129         } else {
 130                 reset( $a );
 131                 reset( $b );
 132                 while ( ( list( , $valueA ) = each( $a ) ) && ( list( , $valueB ) = each( $b ) ) ) {
 133                         $cmp = strcmp( $valueA, $valueB );
 134                         if ( $cmp !== 0 ) {
 135                                 return $cmp;
 136                         }
 137                 }
 138                 return 0;
 139         }
 140 }
 141
 142 /**
 143  * Array lookup
 144  * Returns an array where the values in array $b are replaced by the
 145  * values in array $a with the corresponding keys
 146  *
 147  * @deprecated since 1.22; use array_intersect_key()
 148  * @param $a Array
 149  * @param $b Array
 150  * @return array
 151  */
 152 function wfArrayLookup( $a, $b ) {
 153         wfDeprecated( __FUNCTION__, '1.22' );
 154         return array_flip( array_intersect( array_flip( $a ), array_keys( $b ) ) );
 155 }
 156
 157 /**
 158  * Appends to second array if $value differs from that in $default
 159  *
 160  * @param $key String|Int
 161  * @param $value Mixed
 162  * @param $default Mixed
 163  * @param array $changed to alter
 164  * @throws MWException
 165  */
 166 function wfAppendToArrayIfNotDefault( $key, $value, $default, &$changed ) {
 167         if ( is_null( $changed ) ) {
 168                 throw new MWException( 'GlobalFunctions::wfAppendToArrayIfNotDefault got null' );
 169         }
 170         if ( $default[$key] !== $value ) {
 171                 $changed[$key] = $value;
 172         }
 173 }
 174
 175 /**
 176  * Backwards array plus for people who haven't bothered to read the PHP manual
 177  * XXX: will not darn your socks for you.
 178  *
 179  * @deprecated since 1.22; use array_replace()
 180  * @param $array1 Array
 181  * @param [$array2, [...]] Arrays
 182  * @return Array
 183  */
 184 function wfArrayMerge( $array1/* ... */ ) {
 185         wfDeprecated( __FUNCTION__, '1.22' );
 186         $args = func_get_args();
 187         $args = array_reverse( $args, true );
 188         $out = array();
 189         foreach ( $args as $arg ) {
 190                 $out += $arg;
 191         }
 192         return $out;
 193 }
 194
 195 /**
 196  * Merge arrays in the style of getUserPermissionsErrors, with duplicate removal
 197  * e.g.
 198  *      wfMergeErrorArrays(
 199  *              array( array( 'x' ) ),
 200  *              array( array( 'x', '2' ) ),
 201  *              array( array( 'x' ) ),
 202  *              array( array( 'y' ) )
 203  *      );
 204  * returns:
 205  *              array(
 206  *              array( 'x', '2' ),
 207  *              array( 'x' ),
 208  *              array( 'y' )
 209  *      )
 210  * @param varargs
 211  * @return Array
 212  */
 213 function wfMergeErrorArrays( /*...*/ ) {
 214         $args = func_get_args();
 215         $out = array();
 216         foreach ( $args as $errors ) {
 217                 foreach ( $errors as $params ) {
 218                         # @todo FIXME: Sometimes get nested arrays for $params,
 219                         # which leads to E_NOTICEs
 220                         $spec = implode( "\t", $params );
 221                         $out[$spec] = $params;
 222                 }
 223         }
 224         return array_values( $out );
 225 }
 226
 227 /**
 228  * Insert array into another array after the specified *KEY*
 229  *
 230  * @param array $array The array.
 231  * @param array $insert The array to insert.
 232  * @param $after Mixed: The key to insert after
 233  * @return Array
 234  */
 235 function wfArrayInsertAfter( array $array, array $insert, $after ) {
 236         // Find the offset of the element to insert after.
 237         $keys = array_keys( $array );
 238         $offsetByKey = array_flip( $keys );
 239
 240         $offset = $offsetByKey[$after];
 241
 242         // Insert at the specified offset
 243         $before = array_slice( $array, 0, $offset + 1, true );
 244         $after = array_slice( $array, $offset + 1, count( $array ) - $offset, true );
 245
 246         $output = $before + $insert + $after;
 247
 248         return $output;
 249 }
 250
 251 /**
 252  * Recursively converts the parameter (an object) to an array with the same data
 253  *
 254  * @param $objOrArray Object|Array
 255  * @param $recursive Bool
 256  * @return Array
 257  */
 258 function wfObjectToArray( $objOrArray, $recursive = true ) {
 259         $array = array();
 260         if ( is_object( $objOrArray ) ) {
 261                 $objOrArray = get_object_vars( $objOrArray );
 262         }
 263         foreach ( $objOrArray as $key => $value ) {
 264                 if ( $recursive && ( is_object( $value ) || is_array( $value ) ) ) {
 265                         $value = wfObjectToArray( $value );
 266                 }
 267
 268                 $array[$key] = $value;
 269         }
 270
 271         return $array;
 272 }
 273
 274 /**
 275  * Get a random decimal value between 0 and 1, in a way
 276  * not likely to give duplicate values for any realistic
 277  * number of articles.
 278  *
 279  * @return string
 280  */
 281 function wfRandom() {
 282         # The maximum random value is "only" 2^31-1, so get two random
 283         # values to reduce the chance of dupes
 284         $max = mt_getrandmax() + 1;
 285         $rand = number_format( ( mt_rand() * $max + mt_rand() ) / $max / $max, 12, '.', '' );
 286
 287         return $rand;
 288 }
 289
 290 /**
 291  * Get a random string containing a number of pseudo-random hex
 292  * characters.
 293  * @note This is not secure, if you are trying to generate some sort
 294  *       of token please use MWCryptRand instead.
 295  *
 296  * @param int $length The length of the string to generate
 297  * @return String
 298  * @since 1.20
 299  */
 300 function wfRandomString( $length = 32 ) {
 301         $str = '';
 302         for ( $n = 0; $n < $length; $n += 7 ) {
 303                 $str .= sprintf( '%07x', mt_rand() & 0xfffffff );
 304         }
 305         return substr( $str, 0, $length );
 306 }
 307
 308 /**
 309  * We want some things to be included as literal characters in our title URLs
 310  * for prettiness, which urlencode encodes by default.  According to RFC 1738,
 311  * all of the following should be safe:
 312  *
 313  * ;:@&=$-_.+!*'(),
 314  *
 315  * But + is not safe because it's used to indicate a space; &= are only safe in
 316  * paths and not in queries (and we don't distinguish here); ' seems kind of
 317  * scary; and urlencode() doesn't touch -_. to begin with.  Plus, although /
 318  * is reserved, we don't care.  So the list we unescape is:
 319  *
 320  * ;:@$!*(),/
 321  *
 322  * However, IIS7 redirects fail when the url contains a colon (Bug 22709),
 323  * so no fancy : for IIS7.
 324  *
 325  * %2F in the page titles seems to fatally break for some reason.
 326  *
 327  * @param $s String:
 328  * @return string
 329  */
 330 function wfUrlencode( $s ) {
 331         static $needle;
 332
 333         if ( is_null( $s ) ) {
 334                 $needle = null;
 335                 return '';
 336         }
 337
 338         if ( is_null( $needle ) ) {
 339                 $needle = array( '%3B', '%40', '%24', '%21', '%2A', '%28', '%29', '%2C', '%2F' );
 340                 if ( !isset( $_SERVER['SERVER_SOFTWARE'] ) ||
 341                         ( strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/7' ) === false )
 342                 ) {
 343                         $needle[] = '%3A';
 344                 }
 345         }
 346
 347         $s = urlencode( $s );
 348         $s = str_ireplace(
 349                 $needle,
 350                 array( ';', '@', '$', '!', '*', '(', ')', ',', '/', ':' ),
 351                 $s
 352         );
 353
 354         return $s;
 355 }
 356
 357 /**
 358  * This function takes two arrays as input, and returns a CGI-style string, e.g.
 359  * "days=7&limit=100". Options in the first array override options in the second.
 360  * Options set to null or false will not be output.
 361  *
 362  * @param array $array1 ( String|Array )
 363  * @param array $array2 ( String|Array )
 364  * @param $prefix String
 365  * @return String
 366  */
 367 function wfArrayToCgi( $array1, $array2 = null, $prefix = '' ) {
 368         if ( !is_null( $array2 ) ) {
 369                 $array1 = $array1 + $array2;
 370         }
 371
 372         $cgi = '';
 373         foreach ( $array1 as $key => $value ) {
 374                 if ( !is_null( $value ) && $value !== false ) {
 375                         if ( $cgi != '' ) {
 376                                 $cgi .= '&';
 377                         }
 378                         if ( $prefix !== '' ) {
 379                                 $key = $prefix . "[$key]";
 380                         }
 381                         if ( is_array( $value ) ) {
 382                                 $firstTime = true;
 383                                 foreach ( $value as $k => $v ) {
 384                                         $cgi .= $firstTime ? '' : '&';
 385                                         if ( is_array( $v ) ) {
 386                                                 $cgi .= wfArrayToCgi( $v, null, $key . "[$k]" );
 387                                         } else {
 388                                                 $cgi .= urlencode( $key . "[$k]" ) . '=' . urlencode( $v );
 389                                         }
 390                                         $firstTime = false;
 391                                 }
 392                         } else {
 393                                 if ( is_object( $value ) ) {
 394                                         $value = $value->__toString();
 395                                 }
 396                                 $cgi .= urlencode( $key ) . '=' . urlencode( $value );
 397                         }
 398                 }
 399         }
 400         return $cgi;
 401 }
 402
 403 /**
 404  * This is the logical opposite of wfArrayToCgi(): it accepts a query string as
 405  * its argument and returns the same string in array form.  This allows compatibility
 406  * with legacy functions that accept raw query strings instead of nice
 407  * arrays.  Of course, keys and values are urldecode()d.
 408  *
 409  * @param string $query query string
 410  * @return array Array version of input
 411  */
 412 function wfCgiToArray( $query ) {
 413         if ( isset( $query[0] ) && $query[0] == '?' ) {
 414                 $query = substr( $query, 1 );
 415         }
 416         $bits = explode( '&', $query );
 417         $ret = array();
 418         foreach ( $bits as $bit ) {
 419                 if ( $bit === '' ) {
 420                         continue;
 421                 }
 422                 if ( strpos( $bit, '=' ) === false ) {
 423                         // Pieces like &qwerty become 'qwerty' => '' (at least this is what php does)
 424                         $key = $bit;
 425                         $value = '';
 426                 } else {
 427                         list( $key, $value ) = explode( '=', $bit );
 428                 }
 429                 $key = urldecode( $key );
 430                 $value = urldecode( $value );
 431                 if ( strpos( $key, '[' ) !== false ) {
 432                         $keys = array_reverse( explode( '[', $key ) );
 433                         $key = array_pop( $keys );
 434                         $temp = $value;
 435                         foreach ( $keys as $k ) {
 436                                 $k = substr( $k, 0, -1 );
 437                                 $temp = array( $k => $temp );
 438                         }
 439                         if ( isset( $ret[$key] ) ) {
 440                                 $ret[$key] = array_merge( $ret[$key], $temp );
 441                         } else {
 442                                 $ret[$key] = $temp;
 443                         }
 444                 } else {
 445                         $ret[$key] = $value;
 446                 }
 447         }
 448         return $ret;
 449 }
 450
 451 /**
 452  * Append a query string to an existing URL, which may or may not already
 453  * have query string parameters already. If so, they will be combined.
 454  *
 455  * @param $url String
 456  * @param $query Mixed: string or associative array
 457  * @return string
 458  */
 459 function wfAppendQuery( $url, $query ) {
 460         if ( is_array( $query ) ) {
 461                 $query = wfArrayToCgi( $query );
 462         }
 463         if ( $query != '' ) {
 464                 if ( false === strpos( $url, '?' ) ) {
 465                         $url .= '?';
 466                 } else {
 467                         $url .= '&';
 468                 }
 469                 $url .= $query;
 470         }
 471         return $url;
 472 }
 473
 474 /**
 475  * Expand a potentially local URL to a fully-qualified URL. Assumes $wgServer
 476  * is correct.
 477  *
 478  * The meaning of the PROTO_* constants is as follows:
 479  * PROTO_HTTP: Output a URL starting with http://
 480  * PROTO_HTTPS: Output a URL starting with https://
 481  * PROTO_RELATIVE: Output a URL starting with // (protocol-relative URL)
 482  * PROTO_CURRENT: Output a URL starting with either http:// or https:// , depending
 483  *    on which protocol was used for the current incoming request
 484  * PROTO_CANONICAL: For URLs without a domain, like /w/index.php , use $wgCanonicalServer.
 485  *    For protocol-relative URLs, use the protocol of $wgCanonicalServer
 486  * PROTO_INTERNAL: Like PROTO_CANONICAL, but uses $wgInternalServer instead of $wgCanonicalServer
 487  *
 488  * @todo this won't work with current-path-relative URLs
 489  * like "subdir/foo.html", etc.
 490  *
 491  * @param string $url either fully-qualified or a local path + query
 492  * @param $defaultProto Mixed: one of the PROTO_* constants. Determines the
 493  *    protocol to use if $url or $wgServer is protocol-relative
 494  * @return string Fully-qualified URL, current-path-relative URL or false if
 495  *    no valid URL can be constructed
 496  */
 497 function wfExpandUrl( $url, $defaultProto = PROTO_CURRENT ) {
 498         global $wgServer, $wgCanonicalServer, $wgInternalServer, $wgRequest;
 499         if ( $defaultProto === PROTO_CANONICAL ) {
 500                 $serverUrl = $wgCanonicalServer;
 501         } elseif ( $defaultProto === PROTO_INTERNAL && $wgInternalServer !== false ) {
 502                 // Make $wgInternalServer fall back to $wgServer if not set
 503                 $serverUrl = $wgInternalServer;
 504         } else {
 505                 $serverUrl = $wgServer;
 506                 if ( $defaultProto === PROTO_CURRENT ) {
 507                         $defaultProto = $wgRequest->getProtocol() . '://';
 508                 }
 509         }
 510
 511
 512         // Analyze $serverUrl to obtain its protocol
 513         $bits = wfParseUrl( $serverUrl );
 514         $serverHasProto = $bits && $bits['scheme'] != '';
 515
 516         if ( $defaultProto === PROTO_CANONICAL || $defaultProto === PROTO_INTERNAL ) {
 517                 if ( $serverHasProto ) {
 518                         $defaultProto = $bits['scheme'] . '://';
 519                 } else {
 520                         // $wgCanonicalServer or $wgInternalServer doesn't have a protocol.
 521                         // This really isn't supposed to happen. Fall back to HTTP in this
 522                         // ridiculous case.
 523                         $defaultProto = PROTO_HTTP;
 524                 }
 525         }
 526
 527         $defaultProtoWithoutSlashes = substr( $defaultProto, 0, -2 );
 528
 529         if ( substr( $url, 0, 2 ) == '//' ) {
 530                 $url = $defaultProtoWithoutSlashes . $url;
 531         } elseif ( substr( $url, 0, 1 ) == '/' ) {
 532                 // If $serverUrl is protocol-relative, prepend $defaultProtoWithoutSlashes,
 533                 // otherwise leave it alone.
 534                 $url = ( $serverHasProto ? '' : $defaultProtoWithoutSlashes ) . $serverUrl . $url;
 535         }
 536
 537         $bits = wfParseUrl( $url );
 538         if ( $bits && isset( $bits['path'] ) ) {
 539                 $bits['path'] = wfRemoveDotSegments( $bits['path'] );
 540                 return wfAssembleUrl( $bits );
 541         } elseif ( $bits ) {
 542                 # No path to expand
 543                 return $url;
 544         } elseif ( substr( $url, 0, 1 ) != '/' ) {
 545                 # URL is a relative path
 546                 return wfRemoveDotSegments( $url );
 547         }
 548
 549         # Expanded URL is not valid.
 550         return false;
 551 }
 552
 553 /**
 554  * This function will reassemble a URL parsed with wfParseURL.  This is useful
 555  * if you need to edit part of a URL and put it back together.
 556  *
 557  * This is the basic structure used (brackets contain keys for $urlParts):
 558  * [scheme][delimiter][user]:[pass]@[host]:[port][path]?[query]#[fragment]
 559  *
 560  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 561  *
 562  * @since 1.19
 563  * @param array $urlParts URL parts, as output from wfParseUrl
 564  * @return string URL assembled from its component parts
 565  */
 566 function wfAssembleUrl( $urlParts ) {
 567         $result = '';
 568
 569         if ( isset( $urlParts['delimiter'] ) ) {
 570                 if ( isset( $urlParts['scheme'] ) ) {
 571                         $result .= $urlParts['scheme'];
 572                 }
 573
 574                 $result .= $urlParts['delimiter'];
 575         }
 576
 577         if ( isset( $urlParts['host'] ) ) {
 578                 if ( isset( $urlParts['user'] ) ) {
 579                         $result .= $urlParts['user'];
 580                         if ( isset( $urlParts['pass'] ) ) {
 581                                 $result .= ':' . $urlParts['pass'];
 582                         }
 583                         $result .= '@';
 584                 }
 585
 586                 $result .= $urlParts['host'];
 587
 588                 if ( isset( $urlParts['port'] ) ) {
 589                         $result .= ':' . $urlParts['port'];
 590                 }
 591         }
 592
 593         if ( isset( $urlParts['path'] ) ) {
 594                 $result .= $urlParts['path'];
 595         }
 596
 597         if ( isset( $urlParts['query'] ) ) {
 598                 $result .= '?' . $urlParts['query'];
 599         }
 600
 601         if ( isset( $urlParts['fragment'] ) ) {
 602                 $result .= '#' . $urlParts['fragment'];
 603         }
 604
 605         return $result;
 606 }
 607
 608 /**
 609  * Remove all dot-segments in the provided URL path.  For example,
 610  * '/a/./b/../c/' becomes '/a/c/'.  For details on the algorithm, please see
 611  * RFC3986 section 5.2.4.
 612  *
 613  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 614  *
 615  * @param string $urlPath URL path, potentially containing dot-segments
 616  * @return string URL path with all dot-segments removed
 617  */
 618 function wfRemoveDotSegments( $urlPath ) {
 619         $output = '';
 620         $inputOffset = 0;
 621         $inputLength = strlen( $urlPath );
 622
 623         while ( $inputOffset < $inputLength ) {
 624                 $prefixLengthOne = substr( $urlPath, $inputOffset, 1 );
 625                 $prefixLengthTwo = substr( $urlPath, $inputOffset, 2 );
 626                 $prefixLengthThree = substr( $urlPath, $inputOffset, 3 );
 627                 $prefixLengthFour = substr( $urlPath, $inputOffset, 4 );
 628                 $trimOutput = false;
 629
 630                 if ( $prefixLengthTwo == './' ) {
 631                         # Step A, remove leading "./"
 632                         $inputOffset += 2;
 633                 } elseif ( $prefixLengthThree == '../' ) {
 634                         # Step A, remove leading "../"
 635                         $inputOffset += 3;
 636                 } elseif ( ( $prefixLengthTwo == '/.' ) && ( $inputOffset + 2 == $inputLength ) ) {
 637                         # Step B, replace leading "/.$" with "/"
 638                         $inputOffset += 1;
 639                         $urlPath[$inputOffset] = '/';
 640                 } elseif ( $prefixLengthThree == '/./' ) {
 641                         # Step B, replace leading "/./" with "/"
 642                         $inputOffset += 2;
 643                 } elseif ( $prefixLengthThree == '/..' && ( $inputOffset + 3 == $inputLength ) ) {
 644                         # Step C, replace leading "/..$" with "/" and
 645                         # remove last path component in output
 646                         $inputOffset += 2;
 647                         $urlPath[$inputOffset] = '/';
 648                         $trimOutput = true;
 649                 } elseif ( $prefixLengthFour == '/../' ) {
 650                         # Step C, replace leading "/../" with "/" and
 651                         # remove last path component in output
 652                         $inputOffset += 3;
 653                         $trimOutput = true;
 654                 } elseif ( ( $prefixLengthOne == '.' ) && ( $inputOffset + 1 == $inputLength ) ) {
 655                         # Step D, remove "^.$"
 656                         $inputOffset += 1;
 657                 } elseif ( ( $prefixLengthTwo == '..' ) && ( $inputOffset + 2 == $inputLength ) ) {
 658                         # Step D, remove "^..$"
 659                         $inputOffset += 2;
 660                 } else {
 661                         # Step E, move leading path segment to output
 662                         if ( $prefixLengthOne == '/' ) {
 663                                 $slashPos = strpos( $urlPath, '/', $inputOffset + 1 );
 664                         } else {
 665                                 $slashPos = strpos( $urlPath, '/', $inputOffset );
 666                         }
 667                         if ( $slashPos === false ) {
 668                                 $output .= substr( $urlPath, $inputOffset );
 669                                 $inputOffset = $inputLength;
 670                         } else {
 671                                 $output .= substr( $urlPath, $inputOffset, $slashPos - $inputOffset );
 672                                 $inputOffset += $slashPos - $inputOffset;
 673                         }
 674                 }
 675
 676                 if ( $trimOutput ) {
 677                         $slashPos = strrpos( $output, '/' );
 678                         if ( $slashPos === false ) {
 679                                 $output = '';
 680                         } else {
 681                                 $output = substr( $output, 0, $slashPos );
 682                         }
 683                 }
 684         }
 685
 686         return $output;
 687 }
 688
 689 /**
 690  * Returns a regular expression of url protocols
 691  *
 692  * @param bool $includeProtocolRelative If false, remove '//' from the returned protocol list.
 693  *        DO NOT USE this directly, use wfUrlProtocolsWithoutProtRel() instead
 694  * @return String
 695  */
 696 function wfUrlProtocols( $includeProtocolRelative = true ) {
 697         global $wgUrlProtocols;
 698
 699         // Cache return values separately based on $includeProtocolRelative
 700         static $withProtRel = null, $withoutProtRel = null;
 701         $cachedValue = $includeProtocolRelative ? $withProtRel : $withoutProtRel;
 702         if ( !is_null( $cachedValue ) ) {
 703                 return $cachedValue;
 704         }
 705
 706         // Support old-style $wgUrlProtocols strings, for backwards compatibility
 707         // with LocalSettings files from 1.5
 708         if ( is_array( $wgUrlProtocols ) ) {
 709                 $protocols = array();
 710                 foreach ( $wgUrlProtocols as $protocol ) {
 711                         // Filter out '//' if !$includeProtocolRelative
 712                         if ( $includeProtocolRelative || $protocol !== '//' ) {
 713                                 $protocols[] = preg_quote( $protocol, '/' );
 714                         }
 715                 }
 716
 717                 $retval = implode( '|', $protocols );
 718         } else {
 719                 // Ignore $includeProtocolRelative in this case
 720                 // This case exists for pre-1.6 compatibility, and we can safely assume
 721                 // that '//' won't appear in a pre-1.6 config because protocol-relative
 722                 // URLs weren't supported until 1.18
 723                 $retval = $wgUrlProtocols;
 724         }
 725
 726         // Cache return value
 727         if ( $includeProtocolRelative ) {
 728                 $withProtRel = $retval;
 729         } else {
 730                 $withoutProtRel = $retval;
 731         }
 732         return $retval;
 733 }
 734
 735 /**
 736  * Like wfUrlProtocols(), but excludes '//' from the protocol list. Use this if
 737  * you need a regex that matches all URL protocols but does not match protocol-
 738  * relative URLs
 739  * @return String
 740  */
 741 function wfUrlProtocolsWithoutProtRel() {
 742         return wfUrlProtocols( false );
 743 }
 744
 745 /**
 746  * parse_url() work-alike, but non-broken.  Differences:
 747  *
 748  * 1) Does not raise warnings on bad URLs (just returns false).
 749  * 2) Handles protocols that don't use :// (e.g., mailto: and news:, as well as
 750  *    protocol-relative URLs) correctly.
 751  * 3) Adds a "delimiter" element to the array, either '://', ':' or '//' (see (2)).
 752  *
 753  * @param string $url a URL to parse
 754  * @return Array: bits of the URL in an associative array, per PHP docs
 755  */
 756 function wfParseUrl( $url ) {
 757         global $wgUrlProtocols; // Allow all protocols defined in DefaultSettings/LocalSettings.php
 758
 759         // Protocol-relative URLs are handled really badly by parse_url(). It's so
 760         // bad that the easiest way to handle them is to just prepend 'http:' and
 761         // strip the protocol out later.
 762         $wasRelative = substr( $url, 0, 2 ) == '//';
 763         if ( $wasRelative ) {
 764                 $url = "http:$url";
 765         }
 766         wfSuppressWarnings();
 767         $bits = parse_url( $url );
 768         wfRestoreWarnings();
 769         // parse_url() returns an array without scheme for some invalid URLs, e.g.
 770         // parse_url("%0Ahttp://example.com") == array( 'host' => '%0Ahttp', 'path' => 'example.com' )
 771         if ( !$bits || !isset( $bits['scheme'] ) ) {
 772                 return false;
 773         }
 774
 775         // parse_url() incorrectly handles schemes case-sensitively. Convert it to lowercase.
 776         $bits['scheme'] = strtolower( $bits['scheme'] );
 777
 778         // most of the protocols are followed by ://, but mailto: and sometimes news: not, check for it
 779         if ( in_array( $bits['scheme'] . '://', $wgUrlProtocols ) ) {
 780                 $bits['delimiter'] = '://';
 781         } elseif ( in_array( $bits['scheme'] . ':', $wgUrlProtocols ) ) {
 782                 $bits['delimiter'] = ':';
 783                 // parse_url detects for news: and mailto: the host part of an url as path
 784                 // We have to correct this wrong detection
 785                 if ( isset( $bits['path'] ) ) {
 786                         $bits['host'] = $bits['path'];
 787                         $bits['path'] = '';
 788                 }
 789         } else {
 790                 return false;
 791         }
 792
 793         /* Provide an empty host for eg. file:/// urls (see bug 28627) */
 794         if ( !isset( $bits['host'] ) ) {
 795                 $bits['host'] = '';
 796
 797                 // bug 45069
 798                 if ( isset( $bits['path'] ) ) {
 799                         /* parse_url loses the third / for file:///c:/ urls (but not on variants) */
 800                         if ( substr( $bits['path'], 0, 1 ) !== '/' ) {
 801                                 $bits['path'] = '/' . $bits['path'];
 802                         }
 803                 } else {
 804                         $bits['path'] = '';
 805                 }
 806         }
 807
 808         // If the URL was protocol-relative, fix scheme and delimiter
 809         if ( $wasRelative ) {
 810                 $bits['scheme'] = '';
 811                 $bits['delimiter'] = '//';
 812         }
 813         return $bits;
 814 }
 815
 816 /**
 817  * Take a URL, make sure it's expanded to fully qualified, and replace any
 818  * encoded non-ASCII Unicode characters with their UTF-8 original forms
 819  * for more compact display and legibility for local audiences.
 820  *
 821  * @todo handle punycode domains too
 822  *
 823  * @param $url string
 824  * @return string
 825  */
 826 function wfExpandIRI( $url ) {
 827         return preg_replace_callback(
 828                 '/((?:%[89A-F][0-9A-F])+)/i',
 829                 'wfExpandIRI_callback',
 830                 wfExpandUrl( $url )
 831         );
 832 }
 833
 834 /**
 835  * Private callback for wfExpandIRI
 836  * @param array $matches
 837  * @return string
 838  */
 839 function wfExpandIRI_callback( $matches ) {
 840         return urldecode( $matches[1] );
 841 }
 842
 843 /**
 844  * Make URL indexes, appropriate for the el_index field of externallinks.
 845  *
 846  * @param $url String
 847  * @return array
 848  */
 849 function wfMakeUrlIndexes( $url ) {
 850         $bits = wfParseUrl( $url );
 851
 852         // Reverse the labels in the hostname, convert to lower case
 853         // For emails reverse domainpart only
 854         if ( $bits['scheme'] == 'mailto' ) {
 855                 $mailparts = explode( '@', $bits['host'], 2 );
 856                 if ( count( $mailparts ) === 2 ) {
 857                         $domainpart = strtolower( implode( '.', array_reverse( explode( '.', $mailparts[1] ) ) ) );
 858                 } else {
 859                         // No domain specified, don't mangle it
 860                         $domainpart = '';
 861                 }
 862                 $reversedHost = $domainpart . '@' . $mailparts[0];
 863         } else {
 864                 $reversedHost = strtolower( implode( '.', array_reverse( explode( '.', $bits['host'] ) ) ) );
 865         }
 866         // Add an extra dot to the end
 867         // Why? Is it in wrong place in mailto links?
 868         if ( substr( $reversedHost, -1, 1 ) !== '.' ) {
 869                 $reversedHost .= '.';
 870         }
 871         // Reconstruct the pseudo-URL
 872         $prot = $bits['scheme'];
 873         $index = $prot . $bits['delimiter'] . $reversedHost;
 874         // Leave out user and password. Add the port, path, query and fragment
 875         if ( isset( $bits['port'] ) ) {
 876                 $index .= ':' . $bits['port'];
 877         }
 878         if ( isset( $bits['path'] ) ) {
 879                 $index .= $bits['path'];
 880         } else {
 881                 $index .= '/';
 882         }
 883         if ( isset( $bits['query'] ) ) {
 884                 $index .= '?' . $bits['query'];
 885         }
 886         if ( isset( $bits['fragment'] ) ) {
 887                 $index .= '#' . $bits['fragment'];
 888         }
 889
 890         if ( $prot == '' ) {
 891                 return array( "http:$index", "https:$index" );
 892         } else {
 893                 return array( $index );
 894         }
 895 }
 896
 897 /**
 898  * Check whether a given URL has a domain that occurs in a given set of domains
 899  * @param string $url URL
 900  * @param array $domains Array of domains (strings)
 901  * @return bool True if the host part of $url ends in one of the strings in $domains
 902  */
 903 function wfMatchesDomainList( $url, $domains ) {
 904         $bits = wfParseUrl( $url );
 905         if ( is_array( $bits ) && isset( $bits['host'] ) ) {
 906                 $host = '.' . $bits['host'];
 907                 foreach ( (array)$domains as $domain ) {
 908                         $domain = '.' . $domain;
 909                         if ( substr( $host, -strlen( $domain ) ) === $domain ) {
 910                                 return true;
 911                         }
 912                 }
 913         }
 914         return false;
 915 }
 916
 917 /**
 918  * Sends a line to the debug log if enabled or, optionally, to a comment in output.
 919  * In normal operation this is a NOP.
 920  *
 921  * Controlling globals:
 922  * $wgDebugLogFile - points to the log file
 923  * $wgProfileOnly - if set, normal debug messages will not be recorded.
 924  * $wgDebugRawPage - if false, 'action=raw' hits will not result in debug output.
 925  * $wgDebugComments - if on, some debug items may appear in comments in the HTML output.
 926  *
 927  * @param $text String
 928  * @param bool $logonly set true to avoid appearing in HTML when $wgDebugComments is set
 929  */
 930 function wfDebug( $text, $logonly = false ) {
 931         global $wgDebugLogFile, $wgProfileOnly, $wgDebugRawPage, $wgDebugLogPrefix;
 932
 933         if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
 934                 return;
 935         }
 936
 937         $timer = wfDebugTimer();
 938         if ( $timer !== '' ) {
 939                 $text = preg_replace( '/[^\n]/', $timer . '\0', $text, 1 );
 940         }
 941
 942         if ( !$logonly ) {
 943                 MWDebug::debugMsg( $text );
 944         }
 945
 946         if ( $wgDebugLogFile != '' && !$wgProfileOnly ) {
 947                 # Strip unprintables; they can switch terminal modes when binary data
 948                 # gets dumped, which is pretty annoying.
 949                 $text = preg_replace( '![\x00-\x08\x0b\x0c\x0e-\x1f]!', ' ', $text );
 950                 $text = $wgDebugLogPrefix . $text;
 951                 wfErrorLog( $text, $wgDebugLogFile );
 952         }
 953 }
 954
 955 /**
 956  * Returns true if debug logging should be suppressed if $wgDebugRawPage = false
 957  * @return bool
 958  */
 959 function wfIsDebugRawPage() {
 960         static $cache;
 961         if ( $cache !== null ) {
 962                 return $cache;
 963         }
 964         # Check for raw action using $_GET not $wgRequest, since the latter might not be initialised yet
 965         if ( ( isset( $_GET['action'] ) && $_GET['action'] == 'raw' )
 966                 || (
 967                         isset( $_SERVER['SCRIPT_NAME'] )
 968                         && substr( $_SERVER['SCRIPT_NAME'], -8 ) == 'load.php'
 969                 ) )
 970         {
 971                 $cache = true;
 972         } else {
 973                 $cache = false;
 974         }
 975         return $cache;
 976 }
 977
 978 /**
 979  * Get microsecond timestamps for debug logs
 980  *
 981  * @return string
 982  */
 983 function wfDebugTimer() {
 984         global $wgDebugTimestamps, $wgRequestTime;
 985
 986         if ( !$wgDebugTimestamps ) {
 987                 return '';
 988         }
 989
 990         $prefix = sprintf( "%6.4f", microtime( true ) - $wgRequestTime );
 991         $mem = sprintf( "%5.1fM", ( memory_get_usage( true ) / ( 1024 * 1024 ) ) );
 992         return "$prefix $mem  ";
 993 }
 994
 995 /**
 996  * Send a line giving PHP memory usage.
 997  *
 998  * @param bool $exact print exact values instead of kilobytes (default: false)
 999  */
1000 function wfDebugMem( $exact = false ) {
1001         $mem = memory_get_usage();
1002         if ( !$exact ) {
1003                 $mem = floor( $mem / 1024 ) . ' kilobytes';
1004         } else {
1005                 $mem .= ' bytes';
1006         }
1007         wfDebug( "Memory usage: $mem\n" );
1008 }
1009
1010 /**
1011  * Send a line to a supplementary debug log file, if configured, or main debug log if not.
1012  * To configure a supplementary log file, set $wgDebugLogGroups[$logGroup] to a string
1013  * filename or an associative array mapping 'destination' to the desired filename. The
1014  * associative array may also contain a 'sample' key with an integer value, specifying
1015  * a sampling factor.
1016  *
1017  * @since 1.23 support for sampling log messages via $wgDebugLogGroups.
1018  *
1019  * @param $logGroup String
1020  * @param $text String
1021  * @param bool $public whether to log the event in the public log if no private
1022  *                     log file is specified, (default true)
1023  */
1024 function wfDebugLog( $logGroup, $text, $public = true ) {
1025         global $wgDebugLogGroups;
1026         $text = trim( $text ) . "\n";
1027
1028         if ( !isset( $wgDebugLogGroups[$logGroup] ) ) {
1029                 if ( $public === true ) {
1030                         wfDebug( "[$logGroup] $text", false );
1031                 }
1032                 return;
1033         }
1034
1035         $logConfig = $wgDebugLogGroups[$logGroup];
1036         if ( is_array( $logConfig ) ) {
1037                 if ( isset( $logConfig['sample'] ) && mt_rand( 1, $logConfig['sample'] ) !== 1 ) {
1038                         return;
1039                 }
1040                 $destination = $logConfig['destination'];
1041         } else {
1042                 $destination = strval( $logConfig );
1043         }
1044
1045         $time = wfTimestamp( TS_DB );
1046         $wiki = wfWikiID();
1047         $host = wfHostname();
1048         wfErrorLog( "$time $host $wiki: $text", $destination );
1049 }
1050
1051 /**
1052  * Log for database errors
1053  *
1054  * @param string $text database error message.
1055  */
1056 function wfLogDBError( $text ) {
1057         global $wgDBerrorLog, $wgDBerrorLogTZ;
1058         static $logDBErrorTimeZoneObject = null;
1059
1060         if ( $wgDBerrorLog ) {
1061                 $host = wfHostname();
1062                 $wiki = wfWikiID();
1063
1064                 if ( $wgDBerrorLogTZ && !$logDBErrorTimeZoneObject ) {
1065                         $logDBErrorTimeZoneObject = new DateTimeZone( $wgDBerrorLogTZ );
1066                 }
1067
1068                 // Workaround for https://bugs.php.net/bug.php?id=52063
1069                 // Can be removed when min PHP > 5.3.2
1070                 if ( $logDBErrorTimeZoneObject === null ) {
1071                         $d = date_create( "now" );
1072                 } else {
1073                         $d = date_create( "now", $logDBErrorTimeZoneObject );
1074                 }
1075
1076                 $date = $d->format( 'D M j G:i:s T Y' );
1077
1078                 $text = "$date\t$host\t$wiki\t$text";
1079                 wfErrorLog( $text, $wgDBerrorLog );
1080         }
1081 }
1082
1083 /**
1084  * Throws a warning that $function is deprecated
1085  *
1086  * @param $function String
1087  * @param string|bool $version Version of MediaWiki that the function
1088  *    was deprecated in (Added in 1.19).
1089  * @param string|bool $component Added in 1.19.
1090  * @param $callerOffset integer: How far up the call stack is the original
1091  *    caller. 2 = function that called the function that called
1092  *    wfDeprecated (Added in 1.20)
1093  *
1094  * @return null
1095  */
1096 function wfDeprecated( $function, $version = false, $component = false, $callerOffset = 2 ) {
1097         MWDebug::deprecated( $function, $version, $component, $callerOffset + 1 );
1098 }
1099
1100 /**
1101  * Send a warning either to the debug log or in a PHP error depending on
1102  * $wgDevelopmentWarnings. To log warnings in production, use wfLogWarning() instead.
1103  *
1104  * @param string $msg message to send
1105  * @param $callerOffset Integer: number of items to go back in the backtrace to
1106  *        find the correct caller (1 = function calling wfWarn, ...)
1107  * @param $level Integer: PHP error level; defaults to E_USER_NOTICE;
1108  *        only used when $wgDevelopmentWarnings is true
1109  */
1110 function wfWarn( $msg, $callerOffset = 1, $level = E_USER_NOTICE ) {
1111         MWDebug::warning( $msg, $callerOffset + 1, $level, 'auto' );
1112 }
1113
1114 /**
1115  * Send a warning as a PHP error and the debug log. This is intended for logging
1116  * warnings in production. For logging development warnings, use WfWarn instead.
1117  *
1118  * @param $msg String: message to send
1119  * @param $callerOffset Integer: number of items to go back in the backtrace to
1120  *        find the correct caller (1 = function calling wfLogWarning, ...)
1121  * @param $level Integer: PHP error level; defaults to E_USER_WARNING
1122  */
1123 function wfLogWarning( $msg, $callerOffset = 1, $level = E_USER_WARNING ) {
1124         MWDebug::warning( $msg, $callerOffset + 1, $level, 'production' );
1125 }
1126
1127 /**
1128  * Log to a file without getting "file size exceeded" signals.
1129  *
1130  * Can also log to TCP or UDP with the syntax udp://host:port/prefix. This will
1131  * send lines to the specified port, prefixed by the specified prefix and a space.
1132  *
1133  * @param $text String
1134  * @param string $file filename
1135  * @throws MWException
1136  */
1137 function wfErrorLog( $text, $file ) {
1138         if ( substr( $file, 0, 4 ) == 'udp:' ) {
1139                 # Needs the sockets extension
1140                 if ( preg_match( '!^(tcp|udp):(?://)?\[([0-9a-fA-F:]+)\]:(\d+)(?:/(.*))?$!', $file, $m ) ) {
1141                         // IPv6 bracketed host
1142                         $host = $m[2];
1143                         $port = intval( $m[3] );
1144                         $prefix = isset( $m[4] ) ? $m[4] : false;
1145                         $domain = AF_INET6;
1146                 } elseif ( preg_match( '!^(tcp|udp):(?://)?([a-zA-Z0-9.-]+):(\d+)(?:/(.*))?$!', $file, $m ) ) {
1147                         $host = $m[2];
1148                         if ( !IP::isIPv4( $host ) ) {
1149                                 $host = gethostbyname( $host );
1150                         }
1151                         $port = intval( $m[3] );
1152                         $prefix = isset( $m[4] ) ? $m[4] : false;
1153                         $domain = AF_INET;
1154                 } else {
1155                         throw new MWException( __METHOD__ . ': Invalid UDP specification' );
1156                 }
1157
1158                 // Clean it up for the multiplexer
1159                 if ( strval( $prefix ) !== '' ) {
1160                         $text = preg_replace( '/^/m', $prefix . ' ', $text );
1161
1162                         // Limit to 64KB
1163                         if ( strlen( $text ) > 65506 ) {
1164                                 $text = substr( $text, 0, 65506 );
1165                         }
1166
1167                         if ( substr( $text, -1 ) != "\n" ) {
1168                                 $text .= "\n";
1169                         }
1170                 } elseif ( strlen( $text ) > 65507 ) {
1171                         $text = substr( $text, 0, 65507 );
1172                 }
1173
1174                 $sock = socket_create( $domain, SOCK_DGRAM, SOL_UDP );
1175                 if ( !$sock ) {
1176                         return;
1177                 }
1178
1179                 socket_sendto( $sock, $text, strlen( $text ), 0, $host, $port );
1180                 socket_close( $sock );
1181         } else {
1182                 wfSuppressWarnings();
1183                 $exists = file_exists( $file );
1184                 $size = $exists ? filesize( $file ) : false;
1185                 if ( !$exists || ( $size !== false && $size + strlen( $text ) < 0x7fffffff ) ) {
1186                         file_put_contents( $file, $text, FILE_APPEND );
1187                 }
1188                 wfRestoreWarnings();
1189         }
1190 }
1191
1192 /**
1193  * @todo document
1194  */
1195 function wfLogProfilingData() {
1196         global $wgRequestTime, $wgDebugLogFile, $wgDebugRawPage, $wgRequest;
1197         global $wgProfileLimit, $wgUser;
1198
1199         StatCounter::singleton()->flush();
1200
1201         $profiler = Profiler::instance();
1202
1203         # Profiling must actually be enabled...
1204         if ( $profiler->isStub() ) {
1205                 return;
1206         }
1207
1208         // Get total page request time and only show pages that longer than
1209         // $wgProfileLimit time (default is 0)
1210         $elapsed = microtime( true ) - $wgRequestTime;
1211         if ( $elapsed <= $wgProfileLimit ) {
1212                 return;
1213         }
1214
1215         $profiler->logData();
1216
1217         // Check whether this should be logged in the debug file.
1218         if ( $wgDebugLogFile == '' || ( !$wgDebugRawPage && wfIsDebugRawPage() ) ) {
1219                 return;
1220         }
1221
1222         $forward = '';
1223         if ( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
1224                 $forward = ' forwarded for ' . $_SERVER['HTTP_X_FORWARDED_FOR'];
1225         }
1226         if ( !empty( $_SERVER['HTTP_CLIENT_IP'] ) ) {
1227                 $forward .= ' client IP ' . $_SERVER['HTTP_CLIENT_IP'];
1228         }
1229         if ( !empty( $_SERVER['HTTP_FROM'] ) ) {
1230                 $forward .= ' from ' . $_SERVER['HTTP_FROM'];
1231         }
1232         if ( $forward ) {
1233                 $forward = "\t(proxied via {$_SERVER['REMOTE_ADDR']}{$forward})";
1234         }
1235         // Don't load $wgUser at this late stage just for statistics purposes
1236         // @todo FIXME: We can detect some anons even if it is not loaded. See User::getId()
1237         if ( $wgUser->isItemLoaded( 'id' ) && $wgUser->isAnon() ) {
1238                 $forward .= ' anon';
1239         }
1240
1241         // Command line script uses a FauxRequest object which does not have
1242         // any knowledge about an URL and throw an exception instead.
1243         try {
1244                 $requestUrl = $wgRequest->getRequestURL();
1245         } catch ( MWException $e ) {
1246                 $requestUrl = 'n/a';
1247         }
1248
1249         $log = sprintf( "%s\t%04.3f\t%s\n",
1250                 gmdate( 'YmdHis' ), $elapsed,
1251                 urldecode( $requestUrl . $forward ) );
1252
1253         wfErrorLog( $log . $profiler->getOutput(), $wgDebugLogFile );
1254 }
1255
1256 /**
1257  * Increment a statistics counter
1258  *
1259  * @param $key String
1260  * @param $count Int
1261  * @return void
1262  */
1263 function wfIncrStats( $key, $count = 1 ) {
1264         StatCounter::singleton()->incr( $key, $count );
1265 }
1266
1267 /**
1268  * Check whether the wiki is in read-only mode.
1269  *
1270  * @return bool
1271  */
1272 function wfReadOnly() {
1273         return wfReadOnlyReason() !== false;
1274 }
1275
1276 /**
1277  * Get the value of $wgReadOnly or the contents of $wgReadOnlyFile.
1278  *
1279  * @return string|bool: String when in read-only mode; false otherwise
1280  */
1281 function wfReadOnlyReason() {
1282         global $wgReadOnly, $wgReadOnlyFile;
1283
1284         if ( $wgReadOnly === null ) {
1285                 // Set $wgReadOnly for faster access next time
1286                 if ( is_file( $wgReadOnlyFile ) && filesize( $wgReadOnlyFile ) > 0 ) {
1287                         $wgReadOnly = file_get_contents( $wgReadOnlyFile );
1288                 } else {
1289                         $wgReadOnly = false;
1290                 }
1291         }
1292
1293         return $wgReadOnly;
1294 }
1295
1296 /**
1297  * Return a Language object from $langcode
1298  *
1299  * @param $langcode Mixed: either:
1300  *                  - a Language object
1301  *                  - code of the language to get the message for, if it is
1302  *                    a valid code create a language for that language, if
1303  *                    it is a string but not a valid code then make a basic
1304  *                    language object
1305  *                  - a boolean: if it's false then use the global object for
1306  *                    the current user's language (as a fallback for the old parameter
1307  *                    functionality), or if it is true then use global object
1308  *                    for the wiki's content language.
1309  * @return Language object
1310  */
1311 function wfGetLangObj( $langcode = false ) {
1312         # Identify which language to get or create a language object for.
1313         # Using is_object here due to Stub objects.
1314         if ( is_object( $langcode ) ) {
1315                 # Great, we already have the object (hopefully)!
1316                 return $langcode;
1317         }
1318
1319         global $wgContLang, $wgLanguageCode;
1320         if ( $langcode === true || $langcode === $wgLanguageCode ) {
1321                 # $langcode is the language code of the wikis content language object.
1322                 # or it is a boolean and value is true
1323                 return $wgContLang;
1324         }
1325
1326         global $wgLang;
1327         if ( $langcode === false || $langcode === $wgLang->getCode() ) {
1328                 # $langcode is the language code of user language object.
1329                 # or it was a boolean and value is false
1330                 return $wgLang;
1331         }
1332
1333         $validCodes = array_keys( Language::fetchLanguageNames() );
1334         if ( in_array( $langcode, $validCodes ) ) {
1335                 # $langcode corresponds to a valid language.
1336                 return Language::factory( $langcode );
1337         }
1338
1339         # $langcode is a string, but not a valid language code; use content language.
1340         wfDebug( "Invalid language code passed to wfGetLangObj, falling back to content language.\n" );
1341         return $wgContLang;
1342 }
1343
1344 /**
1345  * Old function when $wgBetterDirectionality existed
1346  * All usage removed, wfUILang can be removed in near future
1347  *
1348  * @deprecated since 1.18
1349  * @return Language
1350  */
1351 function wfUILang() {
1352         wfDeprecated( __METHOD__, '1.18' );
1353         global $wgLang;
1354         return $wgLang;
1355 }
1356
1357 /**
1358  * This is the function for getting translated interface messages.
1359  *
1360  * @see Message class for documentation how to use them.
1361  * @see https://www.mediawiki.org/wiki/Manual:Messages_API
1362  *
1363  * This function replaces all old wfMsg* functions.
1364  *
1365  * @param $key \string Message key.
1366  * Varargs: normal message parameters.
1367  * @return Message
1368  * @since 1.17
1369  */
1370 function wfMessage( $key /*...*/) {
1371         $params = func_get_args();
1372         array_shift( $params );
1373         if ( isset( $params[0] ) && is_array( $params[0] ) ) {
1374                 $params = $params[0];
1375         }
1376         return new Message( $key, $params );
1377 }
1378
1379 /**
1380  * This function accepts multiple message keys and returns a message instance
1381  * for the first message which is non-empty. If all messages are empty then an
1382  * instance of the first message key is returned.
1383  * @param varargs: message keys
1384  * @return Message
1385  * @since 1.18
1386  */
1387 function wfMessageFallback( /*...*/ ) {
1388         $args = func_get_args();
1389         return call_user_func_array( 'Message::newFallbackSequence', $args );
1390 }
1391
1392 /**
1393  * Get a message from anywhere, for the current user language.
1394  *
1395  * Use wfMsgForContent() instead if the message should NOT
1396  * change depending on the user preferences.
1397  *
1398  * @deprecated since 1.18
1399  *
1400  * @param string $key lookup key for the message, usually
1401  *    defined in languages/Language.php
1402  *
1403  * Parameters to the message, which can be used to insert variable text into
1404  * it, can be passed to this function in the following formats:
1405  * - One per argument, starting at the second parameter
1406  * - As an array in the second parameter
1407  * These are not shown in the function definition.
1408  *
1409  * @return String
1410  */
1411 function wfMsg( $key ) {
1412         wfDeprecated( __METHOD__, '1.21' );
1413
1414         $args = func_get_args();
1415         array_shift( $args );
1416         return wfMsgReal( $key, $args );
1417 }
1418
1419 /**
1420  * Same as above except doesn't transform the message
1421  *
1422  * @deprecated since 1.18
1423  *
1424  * @param $key String
1425  * @return String
1426  */
1427 function wfMsgNoTrans( $key ) {
1428         wfDeprecated( __METHOD__, '1.21' );
1429
1430         $args = func_get_args();
1431         array_shift( $args );
1432         return wfMsgReal( $key, $args, true, false, false );
1433 }
1434
1435 /**
1436  * Get a message from anywhere, for the current global language
1437  * set with $wgLanguageCode.
1438  *
1439  * Use this if the message should NOT change dependent on the
1440  * language set in the user's preferences. This is the case for
1441  * most text written into logs, as well as link targets (such as
1442  * the name of the copyright policy page). Link titles, on the
1443  * other hand, should be shown in the UI language.
1444  *
1445  * Note that MediaWiki allows users to change the user interface
1446  * language in their preferences, but a single installation
1447  * typically only contains content in one language.
1448  *
1449  * Be wary of this distinction: If you use wfMsg() where you should
1450  * use wfMsgForContent(), a user of the software may have to
1451  * customize potentially hundreds of messages in
1452  * order to, e.g., fix a link in every possible language.
1453  *
1454  * @deprecated since 1.18
1455  *
1456  * @param string $key lookup key for the message, usually
1457  *     defined in languages/Language.php
1458  * @return String
1459  */
1460 function wfMsgForContent( $key ) {
1461         wfDeprecated( __METHOD__, '1.21' );
1462
1463         global $wgForceUIMsgAsContentMsg;
1464         $args = func_get_args();
1465         array_shift( $args );
1466         $forcontent = true;
1467         if ( is_array( $wgForceUIMsgAsContentMsg ) &&
1468                 in_array( $key, $wgForceUIMsgAsContentMsg ) )
1469         {
1470                 $forcontent = false;
1471         }
1472         return wfMsgReal( $key, $args, true, $forcontent );
1473 }
1474
1475 /**
1476  * Same as above except doesn't transform the message
1477  *
1478  * @deprecated since 1.18
1479  *
1480  * @param $key String
1481  * @return String
1482  */
1483 function wfMsgForContentNoTrans( $key ) {
1484         wfDeprecated( __METHOD__, '1.21' );
1485
1486         global $wgForceUIMsgAsContentMsg;
1487         $args = func_get_args();
1488         array_shift( $args );
1489         $forcontent = true;
1490         if ( is_array( $wgForceUIMsgAsContentMsg ) &&
1491                 in_array( $key, $wgForceUIMsgAsContentMsg ) )
1492         {
1493                 $forcontent = false;
1494         }
1495         return wfMsgReal( $key, $args, true, $forcontent, false );
1496 }
1497
1498 /**
1499  * Really get a message
1500  *
1501  * @deprecated since 1.18
1502  *
1503  * @param string $key key to get.
1504  * @param $args
1505  * @param $useDB Boolean
1506  * @param $forContent Mixed: Language code, or false for user lang, true for content lang.
1507  * @param $transform Boolean: Whether or not to transform the message.
1508  * @return String: the requested message.
1509  */
1510 function wfMsgReal( $key, $args, $useDB = true, $forContent = false, $transform = true ) {
1511         wfDeprecated( __METHOD__, '1.21' );
1512
1513         wfProfileIn( __METHOD__ );
1514         $message = wfMsgGetKey( $key, $useDB, $forContent, $transform );
1515         $message = wfMsgReplaceArgs( $message, $args );
1516         wfProfileOut( __METHOD__ );
1517         return $message;
1518 }
1519
1520 /**
1521  * Fetch a message string value, but don't replace any keys yet.
1522  *
1523  * @deprecated since 1.18
1524  *
1525  * @param $key String
1526  * @param $useDB Bool
1527  * @param string $langCode Code of the language to get the message for, or
1528  *                  behaves as a content language switch if it is a boolean.
1529  * @param $transform Boolean: whether to parse magic words, etc.
1530  * @return string
1531  */
1532 function wfMsgGetKey( $key, $useDB = true, $langCode = false, $transform = true ) {
1533         wfDeprecated( __METHOD__, '1.21' );
1534
1535         wfRunHooks( 'NormalizeMessageKey', array( &$key, &$useDB, &$langCode, &$transform ) );
1536
1537         $cache = MessageCache::singleton();
1538         $message = $cache->get( $key, $useDB, $langCode );
1539         if ( $message === false ) {
1540                 $message = '&lt;' . htmlspecialchars( $key ) . '&gt;';
1541         } elseif ( $transform ) {
1542                 $message = $cache->transform( $message );
1543         }
1544         return $message;
1545 }
1546
1547 /**
1548  * Replace message parameter keys on the given formatted output.
1549  *
1550  * @param $message String
1551  * @param $args Array
1552  * @return string
1553  * @private
1554  */
1555 function wfMsgReplaceArgs( $message, $args ) {
1556         # Fix windows line-endings
1557         # Some messages are split with explode("\n", $msg)
1558         $message = str_replace( "\r", '', $message );
1559
1560         // Replace arguments
1561         if ( count( $args ) ) {
1562                 if ( is_array( $args[0] ) ) {
1563                         $args = array_values( $args[0] );
1564                 }
1565                 $replacementKeys = array();
1566                 foreach ( $args as $n => $param ) {
1567                         $replacementKeys['$' . ( $n + 1 )] = $param;
1568                 }
1569                 $message = strtr( $message, $replacementKeys );
1570         }
1571
1572         return $message;
1573 }
1574
1575 /**
1576  * Return an HTML-escaped version of a message.
1577  * Parameter replacements, if any, are done *after* the HTML-escaping,
1578  * so parameters may contain HTML (eg links or form controls). Be sure
1579  * to pre-escape them if you really do want plaintext, or just wrap
1580  * the whole thing in htmlspecialchars().
1581  *
1582  * @deprecated since 1.18
1583  *
1584  * @param $key String
1585  * @param string ... parameters
1586  * @return string
1587  */
1588 function wfMsgHtml( $key ) {
1589         wfDeprecated( __METHOD__, '1.21' );
1590
1591         $args = func_get_args();
1592         array_shift( $args );
1593         return wfMsgReplaceArgs( htmlspecialchars( wfMsgGetKey( $key ) ), $args );
1594 }
1595
1596 /**
1597  * Return an HTML version of message
1598  * Parameter replacements, if any, are done *after* parsing the wiki-text message,
1599  * so parameters may contain HTML (eg links or form controls). Be sure
1600  * to pre-escape them if you really do want plaintext, or just wrap
1601  * the whole thing in htmlspecialchars().
1602  *
1603  * @deprecated since 1.18
1604  *
1605  * @param $key String
1606  * @param string ... parameters
1607  * @return string
1608  */
1609 function wfMsgWikiHtml( $key ) {
1610         wfDeprecated( __METHOD__, '1.21' );
1611
1612         $args = func_get_args();
1613         array_shift( $args );
1614         return wfMsgReplaceArgs(
1615                 MessageCache::singleton()->parse( wfMsgGetKey( $key ), null,
1616                 /* can't be set to false */ true, /* interface */ true )->getText(),
1617                 $args );
1618 }
1619
1620 /**
1621  * Returns message in the requested format
1622  *
1623  * @deprecated since 1.18
1624  *
1625  * @param string $key key of the message
1626  * @param array $options processing rules. Can take the following options:
1627  *   <i>parse</i>: parses wikitext to HTML
1628  *   <i>parseinline</i>: parses wikitext to HTML and removes the surrounding
1629  *       p's added by parser or tidy
1630  *   <i>escape</i>: filters message through htmlspecialchars
1631  *   <i>escapenoentities</i>: same, but allows entity references like &#160; through
1632  *   <i>replaceafter</i>: parameters are substituted after parsing or escaping
1633  *   <i>parsemag</i>: transform the message using magic phrases
1634  *   <i>content</i>: fetch message for content language instead of interface
1635  * Also can accept a single associative argument, of the form 'language' => 'xx':
1636  *   <i>language</i>: Language object or language code to fetch message for
1637  *       (overridden by <i>content</i>).
1638  * Behavior for conflicting options (e.g., parse+parseinline) is undefined.
1639  *
1640  * @return String
1641  */
1642 function wfMsgExt( $key, $options ) {
1643         wfDeprecated( __METHOD__, '1.21' );
1644
1645         $args = func_get_args();
1646         array_shift( $args );
1647         array_shift( $args );
1648         $options = (array)$options;
1649
1650         foreach ( $options as $arrayKey => $option ) {
1651                 if ( !preg_match( '/^[0-9]+|language$/', $arrayKey ) ) {
1652                         # An unknown index, neither numeric nor "language"
1653                         wfWarn( "wfMsgExt called with incorrect parameter key $arrayKey", 1, E_USER_WARNING );
1654                 } elseif ( preg_match( '/^[0-9]+$/', $arrayKey ) && !in_array( $option,
1655                 array( 'parse', 'parseinline', 'escape', 'escapenoentities',
1656                 'replaceafter', 'parsemag', 'content' ) ) ) {
1657                         # A numeric index with unknown value
1658                         wfWarn( "wfMsgExt called with incorrect parameter $option", 1, E_USER_WARNING );
1659                 }
1660         }
1661
1662         if ( in_array( 'content', $options, true ) ) {
1663                 $forContent = true;
1664                 $langCode = true;
1665                 $langCodeObj = null;
1666         } elseif ( array_key_exists( 'language', $options ) ) {
1667                 $forContent = false;
1668                 $langCode = wfGetLangObj( $options['language'] );
1669                 $langCodeObj = $langCode;
1670         } else {
1671                 $forContent = false;
1672                 $langCode = false;
1673                 $langCodeObj = null;
1674         }
1675
1676         $string = wfMsgGetKey( $key, /*DB*/true, $langCode, /*Transform*/false );
1677
1678         if ( !in_array( 'replaceafter', $options, true ) ) {
1679                 $string = wfMsgReplaceArgs( $string, $args );
1680         }
1681
1682         $messageCache = MessageCache::singleton();
1683         $parseInline = in_array( 'parseinline', $options, true );
1684         if ( in_array( 'parse', $options, true ) || $parseInline ) {
1685                 $string = $messageCache->parse( $string, null, true, !$forContent, $langCodeObj );
1686                 if ( $string instanceof ParserOutput ) {
1687                         $string = $string->getText();
1688                 }
1689
1690                 if ( $parseInline ) {
1691                         $m = array();
1692                         if ( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $string, $m ) ) {
1693                                 $string = $m[1];
1694                         }
1695                 }
1696         } elseif ( in_array( 'parsemag', $options, true ) ) {
1697                 $string = $messageCache->transform( $string,
1698                                 !$forContent, $langCodeObj );
1699         }
1700
1701         if ( in_array( 'escape', $options, true ) ) {
1702                 $string = htmlspecialchars ( $string );
1703         } elseif ( in_array( 'escapenoentities', $options, true ) ) {
1704                 $string = Sanitizer::escapeHtmlAllowEntities( $string );
1705         }
1706
1707         if ( in_array( 'replaceafter', $options, true ) ) {
1708                 $string = wfMsgReplaceArgs( $string, $args );
1709         }
1710
1711         return $string;
1712 }
1713
1714 /**
1715  * Since wfMsg() and co suck, they don't return false if the message key they
1716  * looked up didn't exist but instead the key wrapped in <>'s, this function checks for the
1717  * nonexistence of messages by checking the MessageCache::get() result directly.
1718  *
1719  * @deprecated since 1.18. Use Message::isDisabled().
1720  *
1721  * @param $key      String: the message key looked up
1722  * @return Boolean True if the message *doesn't* exist.
1723  */
1724 function wfEmptyMsg( $key ) {
1725         wfDeprecated( __METHOD__, '1.21' );
1726
1727         return MessageCache::singleton()->get( $key, /*useDB*/true, /*content*/false ) === false;
1728 }
1729
1730 /**
1731  * Throw a debugging exception. This function previously once exited the process,
1732  * but now throws an exception instead, with similar results.
1733  *
1734  * @deprecated since 1.22; just throw an MWException yourself
1735  * @param string $msg message shown when dying.
1736  * @throws MWException
1737  */
1738 function wfDebugDieBacktrace( $msg = '' ) {
1739         wfDeprecated( __FUNCTION__, '1.22' );
1740         throw new MWException( $msg );
1741 }
1742
1743 /**
1744  * Fetch server name for use in error reporting etc.
1745  * Use real server name if available, so we know which machine
1746  * in a server farm generated the current page.
1747  *
1748  * @return string
1749  */
1750 function wfHostname() {
1751         static $host;
1752         if ( is_null( $host ) ) {
1753
1754                 # Hostname overriding
1755                 global $wgOverrideHostname;
1756                 if ( $wgOverrideHostname !== false ) {
1757                         # Set static and skip any detection
1758                         $host = $wgOverrideHostname;
1759                         return $host;
1760                 }
1761
1762                 if ( function_exists( 'posix_uname' ) ) {
1763                         // This function not present on Windows
1764                         $uname = posix_uname();
1765                 } else {
1766                         $uname = false;
1767                 }
1768                 if ( is_array( $uname ) && isset( $uname['nodename'] ) ) {
1769                         $host = $uname['nodename'];
1770                 } elseif ( getenv( 'COMPUTERNAME' ) ) {
1771                         # Windows computer name
1772                         $host = getenv( 'COMPUTERNAME' );
1773                 } else {
1774                         # This may be a virtual server.
1775                         $host = $_SERVER['SERVER_NAME'];
1776                 }
1777         }
1778         return $host;
1779 }
1780
1781 /**
1782  * Returns a HTML comment with the elapsed time since request.
1783  * This method has no side effects.
1784  *
1785  * @return string
1786  */
1787 function wfReportTime() {
1788         global $wgRequestTime, $wgShowHostnames;
1789
1790         $elapsed = microtime( true ) - $wgRequestTime;
1791
1792         return $wgShowHostnames
1793                 ? sprintf( '<!-- Served by %s in %01.3f secs. -->', wfHostname(), $elapsed )
1794                 : sprintf( '<!-- Served in %01.3f secs. -->', $elapsed );
1795 }
1796
1797 /**
1798  * Safety wrapper for debug_backtrace().
1799  *
1800  * With Zend Optimizer 3.2.0 loaded, this causes segfaults under somewhat
1801  * murky circumstances, which may be triggered in part by stub objects
1802  * or other fancy talking'.
1803  *
1804  * Will return an empty array if Zend Optimizer is detected or if
1805  * debug_backtrace is disabled, otherwise the output from
1806  * debug_backtrace() (trimmed).
1807  *
1808  * @param int $limit This parameter can be used to limit the number of stack frames returned
1809  *
1810  * @return array of backtrace information
1811  */
1812 function wfDebugBacktrace( $limit = 0 ) {
1813         static $disabled = null;
1814
1815         if ( extension_loaded( 'Zend Optimizer' ) ) {
1816                 wfDebug( "Zend Optimizer detected; skipping debug_backtrace for safety.\n" );
1817                 return array();
1818         }
1819
1820         if ( is_null( $disabled ) ) {
1821                 $disabled = false;
1822                 $functions = explode( ',', ini_get( 'disable_functions' ) );
1823                 $functions = array_map( 'trim', $functions );
1824                 $functions = array_map( 'strtolower', $functions );
1825                 if ( in_array( 'debug_backtrace', $functions ) ) {
1826                         wfDebug( "debug_backtrace is in disabled_functions\n" );
1827                         $disabled = true;
1828                 }
1829         }
1830         if ( $disabled ) {
1831                 return array();
1832         }
1833
1834         if ( $limit && version_compare( PHP_VERSION, '5.4.0', '>=' ) ) {
1835                 return array_slice( debug_backtrace( DEBUG_BACKTRACE_PROVIDE_OBJECT, $limit + 1 ), 1 );
1836         } else {
1837                 return array_slice( debug_backtrace(), 1 );
1838         }
1839 }
1840
1841 /**
1842  * Get a debug backtrace as a string
1843  *
1844  * @return string
1845  */
1846 function wfBacktrace() {
1847         global $wgCommandLineMode;
1848
1849         if ( $wgCommandLineMode ) {
1850                 $msg = '';
1851         } else {
1852                 $msg = "<ul>\n";
1853         }
1854         $backtrace = wfDebugBacktrace();
1855         foreach ( $backtrace as $call ) {
1856                 if ( isset( $call['file'] ) ) {
1857                         $f = explode( DIRECTORY_SEPARATOR, $call['file'] );
1858                         $file = $f[count( $f ) - 1];
1859                 } else {
1860                         $file = '-';
1861                 }
1862                 if ( isset( $call['line'] ) ) {
1863                         $line = $call['line'];
1864                 } else {
1865                         $line = '-';
1866                 }
1867                 if ( $wgCommandLineMode ) {
1868                         $msg .= "$file line $line calls ";
1869                 } else {
1870                         $msg .= '<li>' . $file . ' line ' . $line . ' calls ';
1871                 }
1872                 if ( !empty( $call['class'] ) ) {
1873                         $msg .= $call['class'] . $call['type'];
1874                 }
1875                 $msg .= $call['function'] . '()';
1876
1877                 if ( $wgCommandLineMode ) {
1878                         $msg .= "\n";
1879                 } else {
1880                         $msg .= "</li>\n";
1881                 }
1882         }
1883         if ( $wgCommandLineMode ) {
1884                 $msg .= "\n";
1885         } else {
1886                 $msg .= "</ul>\n";
1887         }
1888
1889         return $msg;
1890 }
1891
1892 /**
1893  * Get the name of the function which called this function
1894  * wfGetCaller( 1 ) is the function with the wfGetCaller() call (ie. __FUNCTION__)
1895  * wfGetCaller( 2 ) [default] is the caller of the function running wfGetCaller()
1896  * wfGetCaller( 3 ) is the parent of that.
1897  *
1898  * @param $level Int
1899  * @return string
1900  */
1901 function wfGetCaller( $level = 2 ) {
1902         $backtrace = wfDebugBacktrace( $level + 1 );
1903         if ( isset( $backtrace[$level] ) ) {
1904                 return wfFormatStackFrame( $backtrace[$level] );
1905         } else {
1906                 return 'unknown';
1907         }
1908 }
1909
1910 /**
1911  * Return a string consisting of callers in the stack. Useful sometimes
1912  * for profiling specific points.
1913  *
1914  * @param int $limit The maximum depth of the stack frame to return, or false for
1915  *               the entire stack.
1916  * @return String
1917  */
1918 function wfGetAllCallers( $limit = 3 ) {
1919         $trace = array_reverse( wfDebugBacktrace() );
1920         if ( !$limit || $limit > count( $trace ) - 1 ) {
1921                 $limit = count( $trace ) - 1;
1922         }
1923         $trace = array_slice( $trace, -$limit - 1, $limit );
1924         return implode( '/', array_map( 'wfFormatStackFrame', $trace ) );
1925 }
1926
1927 /**
1928  * Return a string representation of frame
1929  *
1930  * @param $frame Array
1931  * @return string
1932  */
1933 function wfFormatStackFrame( $frame ) {
1934         return isset( $frame['class'] ) ?
1935                 $frame['class'] . '::' . $frame['function'] :
1936                 $frame['function'];
1937 }
1938
1939 /* Some generic result counters, pulled out of SearchEngine */
1940
1941 /**
1942  * @todo document
1943  *
1944  * @param $offset Int
1945  * @param $limit Int
1946  * @return String
1947  */
1948 function wfShowingResults( $offset, $limit ) {
1949         return wfMessage( 'showingresults' )->numParams( $limit, $offset + 1 )->parse();
1950 }
1951
1952 /**
1953  * Generate (prev x| next x) (20|50|100...) type links for paging
1954  *
1955  * @param $offset String
1956  * @param $limit Integer
1957  * @param $link String
1958  * @param string $query optional URL query parameter string
1959  * @param bool $atend optional param for specified if this is the last page
1960  * @return String
1961  * @deprecated in 1.19; use Language::viewPrevNext() instead
1962  */
1963 function wfViewPrevNext( $offset, $limit, $link, $query = '', $atend = false ) {
1964         wfDeprecated( __METHOD__, '1.19' );
1965
1966         global $wgLang;
1967
1968         $query = wfCgiToArray( $query );
1969
1970         if ( is_object( $link ) ) {
1971                 $title = $link;
1972         } else {
1973                 $title = Title::newFromText( $link );
1974                 if ( is_null( $title ) ) {
1975                         return false;
1976                 }
1977         }
1978
1979         return $wgLang->viewPrevNext( $title, $offset, $limit, $query, $atend );
1980 }
1981
1982 /**
1983  * @todo document
1984  * @todo FIXME: We may want to blacklist some broken browsers
1985  *
1986  * @param $force Bool
1987  * @return bool Whereas client accept gzip compression
1988  */
1989 function wfClientAcceptsGzip( $force = false ) {
1990         static $result = null;
1991         if ( $result === null || $force ) {
1992                 $result = false;
1993                 if ( isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ) {
1994                         # @todo FIXME: We may want to blacklist some broken browsers
1995                         $m = array();
1996                         if ( preg_match(
1997                                 '/\bgzip(?:;(q)=([0-9]+(?:\.[0-9]+)))?\b/',
1998                                 $_SERVER['HTTP_ACCEPT_ENCODING'],
1999                                 $m )
2000                         )
2001                         {
2002                                 if ( isset( $m[2] ) && ( $m[1] == 'q' ) && ( $m[2] == 0 ) ) {
2003                                         $result = false;
2004                                         return $result;
2005                                 }
2006                                 wfDebug( "wfClientAcceptsGzip: client accepts gzip.\n" );
2007                                 $result = true;
2008                         }
2009                 }
2010         }
2011         return $result;
2012 }
2013
2014 /**
2015  * Obtain the offset and limit values from the request string;
2016  * used in special pages
2017  *
2018  * @param int $deflimit default limit if none supplied
2019  * @param string $optionname Name of a user preference to check against
2020  * @return array
2021  *
2022  */
2023 function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
2024         global $wgRequest;
2025         return $wgRequest->getLimitOffset( $deflimit, $optionname );
2026 }
2027
2028 /**
2029  * Escapes the given text so that it may be output using addWikiText()
2030  * without any linking, formatting, etc. making its way through. This
2031  * is achieved by substituting certain characters with HTML entities.
2032  * As required by the callers, "<nowiki>" is not used.
2033  *
2034  * @param string $text text to be escaped
2035  * @return String
2036  */
2037 function wfEscapeWikiText( $text ) {
2038         static $repl = null, $repl2 = null;
2039         if ( $repl === null ) {
2040                 $repl = array(
2041                         '"' => '&#34;', '&' => '&#38;', "'" => '&#39;', '<' => '&#60;',
2042                         '=' => '&#61;', '>' => '&#62;', '[' => '&#91;', ']' => '&#93;',
2043                         '{' => '&#123;', '|' => '&#124;', '}' => '&#125;', ';' => '&#59;',
2044                         "\n#" => "\n&#35;", "\r#" => "\r&#35;",
2045                         "\n*" => "\n&#42;", "\r*" => "\r&#42;",
2046                         "\n:" => "\n&#58;", "\r:" => "\r&#58;",
2047                         "\n " => "\n&#32;", "\r " => "\r&#32;",
2048                         "\n\n" => "\n&#10;", "\r\n" => "&#13;\n",
2049                         "\n\r" => "\n&#13;", "\r\r" => "\r&#13;",
2050                         "\n\t" => "\n&#9;", "\r\t" => "\r&#9;", // "\n\t\n" is treated like "\n\n"
2051                         "\n----" => "\n&#45;---", "\r----" => "\r&#45;---",
2052                         '__' => '_&#95;', '://' => '&#58;//',
2053                 );
2054
2055                 // We have to catch everything "\s" matches in PCRE
2056                 foreach ( array( 'ISBN', 'RFC', 'PMID' ) as $magic ) {
2057                         $repl["$magic "] = "$magic&#32;";
2058                         $repl["$magic\t"] = "$magic&#9;";
2059                         $repl["$magic\r"] = "$magic&#13;";
2060                         $repl["$magic\n"] = "$magic&#10;";
2061                         $repl["$magic\f"] = "$magic&#12;";
2062                 }
2063
2064                 // And handle protocols that don't use "://"
2065                 global $wgUrlProtocols;
2066                 $repl2 = array();
2067                 foreach ( $wgUrlProtocols as $prot ) {
2068                         if ( substr( $prot, -1 ) === ':' ) {
2069                                 $repl2[] = preg_quote( substr( $prot, 0, -1 ), '/' );
2070                         }
2071                 }
2072                 $repl2 = $repl2 ? '/\b(' . join( '|', $repl2 ) . '):/i' : '/^(?!)/';
2073         }
2074         $text = substr( strtr( "\n$text", $repl ), 1 );
2075         $text = preg_replace( $repl2, '$1&#58;', $text );
2076         return $text;
2077 }
2078
2079 /**
2080  * Get the current unix timestamp with microseconds.  Useful for profiling
2081  * @deprecated since 1.22; call microtime() directly
2082  * @return Float
2083  */
2084 function wfTime() {
2085         wfDeprecated( __FUNCTION__, '1.22' );
2086         return microtime( true );
2087 }
2088
2089 /**
2090  * Sets dest to source and returns the original value of dest
2091  * If source is NULL, it just returns the value, it doesn't set the variable
2092  * If force is true, it will set the value even if source is NULL
2093  *
2094  * @param $dest Mixed
2095  * @param $source Mixed
2096  * @param $force Bool
2097  * @return Mixed
2098  */
2099 function wfSetVar( &$dest, $source, $force = false ) {
2100         $temp = $dest;
2101         if ( !is_null( $source ) || $force ) {
2102                 $dest = $source;
2103         }
2104         return $temp;
2105 }
2106
2107 /**
2108  * As for wfSetVar except setting a bit
2109  *
2110  * @param $dest Int
2111  * @param $bit Int
2112  * @param $state Bool
2113  *
2114  * @return bool
2115  */
2116 function wfSetBit( &$dest, $bit, $state = true ) {
2117         $temp = (bool)( $dest & $bit );
2118         if ( !is_null( $state ) ) {
2119                 if ( $state ) {
2120                         $dest |= $bit;
2121                 } else {
2122                         $dest &= ~$bit;
2123                 }
2124         }
2125         return $temp;
2126 }
2127
2128 /**
2129  * A wrapper around the PHP function var_export().
2130  * Either print it or add it to the regular output ($wgOut).
2131  *
2132  * @param $var mixed A PHP variable to dump.
2133  */
2134 function wfVarDump( $var ) {
2135         global $wgOut;
2136         $s = str_replace( "\n", "<br />\n", var_export( $var, true ) . "\n" );
2137         if ( headers_sent() || !isset( $wgOut ) || !is_object( $wgOut ) ) {
2138                 print $s;
2139         } else {
2140                 $wgOut->addHTML( $s );
2141         }
2142 }
2143
2144 /**
2145  * Provide a simple HTTP error.
2146  *
2147  * @param $code Int|String
2148  * @param $label String
2149  * @param $desc String
2150  */
2151 function wfHttpError( $code, $label, $desc ) {
2152         global $wgOut;
2153         $wgOut->disable();
2154         header( "HTTP/1.0 $code $label" );
2155         header( "Status: $code $label" );
2156         $wgOut->sendCacheControl();
2157
2158         header( 'Content-type: text/html; charset=utf-8' );
2159         print "<!doctype html>" .
2160                 '<html><head><title>' .
2161                 htmlspecialchars( $label ) .
2162                 '</title></head><body><h1>' .
2163                 htmlspecialchars( $label ) .
2164                 '</h1><p>' .
2165                 nl2br( htmlspecialchars( $desc ) ) .
2166                 "</p></body></html>\n";
2167 }
2168
2169 /**
2170  * Clear away any user-level output buffers, discarding contents.
2171  *
2172  * Suitable for 'starting afresh', for instance when streaming
2173  * relatively large amounts of data without buffering, or wanting to
2174  * output image files without ob_gzhandler's compression.
2175  *
2176  * The optional $resetGzipEncoding parameter controls suppression of
2177  * the Content-Encoding header sent by ob_gzhandler; by default it
2178  * is left. See comments for wfClearOutputBuffers() for why it would
2179  * be used.
2180  *
2181  * Note that some PHP configuration options may add output buffer
2182  * layers which cannot be removed; these are left in place.
2183  *
2184  * @param $resetGzipEncoding Bool
2185  */
2186 function wfResetOutputBuffers( $resetGzipEncoding = true ) {
2187         if ( $resetGzipEncoding ) {
2188                 // Suppress Content-Encoding and Content-Length
2189                 // headers from 1.10+s wfOutputHandler
2190                 global $wgDisableOutputCompression;
2191                 $wgDisableOutputCompression = true;
2192         }
2193         while ( $status = ob_get_status() ) {
2194                 if ( $status['type'] == 0 /* PHP_OUTPUT_HANDLER_INTERNAL */ ) {
2195                         // Probably from zlib.output_compression or other
2196                         // PHP-internal setting which can't be removed.
2197                         //
2198                         // Give up, and hope the result doesn't break
2199                         // output behavior.
2200                         break;
2201                 }
2202                 if ( !ob_end_clean() ) {
2203                         // Could not remove output buffer handler; abort now
2204                         // to avoid getting in some kind of infinite loop.
2205                         break;
2206                 }
2207                 if ( $resetGzipEncoding ) {
2208                         if ( $status['name'] == 'ob_gzhandler' ) {
2209                                 // Reset the 'Content-Encoding' field set by this handler
2210                                 // so we can start fresh.
2211                                 header_remove( 'Content-Encoding' );
2212                                 break;
2213                         }
2214                 }
2215         }
2216 }
2217
2218 /**
2219  * More legible than passing a 'false' parameter to wfResetOutputBuffers():
2220  *
2221  * Clear away output buffers, but keep the Content-Encoding header
2222  * produced by ob_gzhandler, if any.
2223  *
2224  * This should be used for HTTP 304 responses, where you need to
2225  * preserve the Content-Encoding header of the real result, but
2226  * also need to suppress the output of ob_gzhandler to keep to spec
2227  * and avoid breaking Firefox in rare cases where the headers and
2228  * body are broken over two packets.
2229  */
2230 function wfClearOutputBuffers() {
2231         wfResetOutputBuffers( false );
2232 }
2233
2234 /**
2235  * Converts an Accept-* header into an array mapping string values to quality
2236  * factors
2237  *
2238  * @param $accept String
2239  * @param string $def default
2240  * @return Array
2241  */
2242 function wfAcceptToPrefs( $accept, $def = '*/*' ) {
2243         # No arg means accept anything (per HTTP spec)
2244         if ( !$accept ) {
2245                 return array( $def => 1.0 );
2246         }
2247
2248         $prefs = array();
2249
2250         $parts = explode( ',', $accept );
2251
2252         foreach ( $parts as $part ) {
2253                 # @todo FIXME: Doesn't deal with params like 'text/html; level=1'
2254                 $values = explode( ';', trim( $part ) );
2255                 $match = array();
2256                 if ( count( $values ) == 1 ) {
2257                         $prefs[$values[0]] = 1.0;
2258                 } elseif ( preg_match( '/q\s*=\s*(\d*\.\d+)/', $values[1], $match ) ) {
2259                         $prefs[$values[0]] = floatval( $match[1] );
2260                 }
2261         }
2262
2263         return $prefs;
2264 }
2265
2266 /**
2267  * Checks if a given MIME type matches any of the keys in the given
2268  * array. Basic wildcards are accepted in the array keys.
2269  *
2270  * Returns the matching MIME type (or wildcard) if a match, otherwise
2271  * NULL if no match.
2272  *
2273  * @param $type String
2274  * @param $avail Array
2275  * @return string
2276  * @private
2277  */
2278 function mimeTypeMatch( $type, $avail ) {
2279         if ( array_key_exists( $type, $avail ) ) {
2280                 return $type;
2281         } else {
2282                 $parts = explode( '/', $type );
2283                 if ( array_key_exists( $parts[0] . '/*', $avail ) ) {
2284                         return $parts[0] . '/*';
2285                 } elseif ( array_key_exists( '*/*', $avail ) ) {
2286                         return '*/*';
2287                 } else {
2288                         return null;
2289                 }
2290         }
2291 }
2292
2293 /**
2294  * Returns the 'best' match between a client's requested internet media types
2295  * and the server's list of available types. Each list should be an associative
2296  * array of type to preference (preference is a float between 0.0 and 1.0).
2297  * Wildcards in the types are acceptable.
2298  *
2299  * @param array $cprefs client's acceptable type list
2300  * @param array $sprefs server's offered types
2301  * @return string
2302  *
2303  * @todo FIXME: Doesn't handle params like 'text/plain; charset=UTF-8'
2304  * XXX: generalize to negotiate other stuff
2305  */
2306 function wfNegotiateType( $cprefs, $sprefs ) {
2307         $combine = array();
2308
2309         foreach ( array_keys( $sprefs ) as $type ) {
2310                 $parts = explode( '/', $type );
2311                 if ( $parts[1] != '*' ) {
2312                         $ckey = mimeTypeMatch( $type, $cprefs );
2313                         if ( $ckey ) {
2314                                 $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
2315                         }
2316                 }
2317         }
2318
2319         foreach ( array_keys( $cprefs ) as $type ) {
2320                 $parts = explode( '/', $type );
2321                 if ( $parts[1] != '*' && !array_key_exists( $type, $sprefs ) ) {
2322                         $skey = mimeTypeMatch( $type, $sprefs );
2323                         if ( $skey ) {
2324                                 $combine[$type] = $sprefs[$skey] * $cprefs[$type];
2325                         }
2326                 }
2327         }
2328
2329         $bestq = 0;
2330         $besttype = null;
2331
2332         foreach ( array_keys( $combine ) as $type ) {
2333                 if ( $combine[$type] > $bestq ) {
2334                         $besttype = $type;
2335                         $bestq = $combine[$type];
2336                 }
2337         }
2338
2339         return $besttype;
2340 }
2341
2342 /**
2343  * Reference-counted warning suppression
2344  *
2345  * @param $end Bool
2346  */
2347 function wfSuppressWarnings( $end = false ) {
2348         static $suppressCount = 0;
2349         static $originalLevel = false;
2350
2351         if ( $end ) {
2352                 if ( $suppressCount ) {
2353                         --$suppressCount;
2354                         if ( !$suppressCount ) {
2355                                 error_reporting( $originalLevel );
2356                         }
2357                 }
2358         } else {
2359                 if ( !$suppressCount ) {
2360                         $originalLevel = error_reporting( E_ALL & ~(
2361                                 E_WARNING |
2362                                 E_NOTICE |
2363                                 E_USER_WARNING |
2364                                 E_USER_NOTICE |
2365                                 E_DEPRECATED |
2366                                 E_USER_DEPRECATED |
2367                                 E_STRICT
2368                         ) );
2369                 }
2370                 ++$suppressCount;
2371         }
2372 }
2373
2374 /**
2375  * Restore error level to previous value
2376  */
2377 function wfRestoreWarnings() {
2378         wfSuppressWarnings( true );
2379 }
2380
2381 # Autodetect, convert and provide timestamps of various types
2382
2383 /**
2384  * Unix time - the number of seconds since 1970-01-01 00:00:00 UTC
2385  */
2386 define( 'TS_UNIX', 0 );
2387
2388 /**
2389  * MediaWiki concatenated string timestamp (YYYYMMDDHHMMSS)
2390  */
2391 define( 'TS_MW', 1 );
2392
2393 /**
2394  * MySQL DATETIME (YYYY-MM-DD HH:MM:SS)
2395  */
2396 define( 'TS_DB', 2 );
2397
2398 /**
2399  * RFC 2822 format, for E-mail and HTTP headers
2400  */
2401 define( 'TS_RFC2822', 3 );
2402
2403 /**
2404  * ISO 8601 format with no timezone: 1986-02-09T20:00:00Z
2405  *
2406  * This is used by Special:Export
2407  */
2408 define( 'TS_ISO_8601', 4 );
2409
2410 /**
2411  * An Exif timestamp (YYYY:MM:DD HH:MM:SS)
2412  *
2413  * @see http://exif.org/Exif2-2.PDF The Exif 2.2 spec, see page 28 for the
2414  *       DateTime tag and page 36 for the DateTimeOriginal and
2415  *       DateTimeDigitized tags.
2416  */
2417 define( 'TS_EXIF', 5 );
2418
2419 /**
2420  * Oracle format time.
2421  */
2422 define( 'TS_ORACLE', 6 );
2423
2424 /**
2425  * Postgres format time.
2426  */
2427 define( 'TS_POSTGRES', 7 );
2428
2429 /**
2430  * ISO 8601 basic format with no timezone: 19860209T200000Z.  This is used by ResourceLoader
2431  */
2432 define( 'TS_ISO_8601_BASIC', 9 );
2433
2434 /**
2435  * Get a timestamp string in one of various formats
2436  *
2437  * @param $outputtype Mixed: A timestamp in one of the supported formats, the
2438  *                    function will autodetect which format is supplied and act
2439  *                    accordingly.
2440  * @param $ts Mixed: optional timestamp to convert, default 0 for the current time
2441  * @return Mixed: String / false The same date in the format specified in $outputtype or false
2442  */
2443 function wfTimestamp( $outputtype = TS_UNIX, $ts = 0 ) {
2444         try {
2445                 $timestamp = new MWTimestamp( $ts );
2446                 return $timestamp->getTimestamp( $outputtype );
2447         } catch ( TimestampException $e ) {
2448                 wfDebug( "wfTimestamp() fed bogus time value: TYPE=$outputtype; VALUE=$ts\n" );
2449                 return false;
2450         }
2451 }
2452
2453 /**
2454  * Return a formatted timestamp, or null if input is null.
2455  * For dealing with nullable timestamp columns in the database.
2456  *
2457  * @param $outputtype Integer
2458  * @param $ts String
2459  * @return String
2460  */
2461 function wfTimestampOrNull( $outputtype = TS_UNIX, $ts = null ) {
2462         if ( is_null( $ts ) ) {
2463                 return null;
2464         } else {
2465                 return wfTimestamp( $outputtype, $ts );
2466         }
2467 }
2468
2469 /**
2470  * Convenience function; returns MediaWiki timestamp for the present time.
2471  *
2472  * @return string
2473  */
2474 function wfTimestampNow() {
2475         # return NOW
2476         return wfTimestamp( TS_MW, time() );
2477 }
2478
2479 /**
2480  * Check if the operating system is Windows
2481  *
2482  * @return Bool: true if it's Windows, False otherwise.
2483  */
2484 function wfIsWindows() {
2485         static $isWindows = null;
2486         if ( $isWindows === null ) {
2487                 $isWindows = substr( php_uname(), 0, 7 ) == 'Windows';
2488         }
2489         return $isWindows;
2490 }
2491
2492 /**
2493  * Check if we are running under HHVM
2494  *
2495  * @return Bool
2496  */
2497 function wfIsHHVM() {
2498         return defined( 'HHVM_VERSION' );
2499 }
2500
2501 /**
2502  * Swap two variables
2503  *
2504  * @param $x Mixed
2505  * @param $y Mixed
2506  */
2507 function swap( &$x, &$y ) {
2508         $z = $x;
2509         $x = $y;
2510         $y = $z;
2511 }
2512
2513 /**
2514  * Tries to get the system directory for temporary files. First
2515  * $wgTmpDirectory is checked, and then the TMPDIR, TMP, and TEMP
2516  * environment variables are then checked in sequence, and if none are
2517  * set try sys_get_temp_dir().
2518  *
2519  * NOTE: When possible, use instead the tmpfile() function to create
2520  * temporary files to avoid race conditions on file creation, etc.
2521  *
2522  * @return String
2523  */
2524 function wfTempDir() {
2525         global $wgTmpDirectory;
2526
2527         if ( $wgTmpDirectory !== false ) {
2528                 return $wgTmpDirectory;
2529         }
2530
2531         $tmpDir = array_map( "getenv", array( 'TMPDIR', 'TMP', 'TEMP' ) );
2532
2533         foreach ( $tmpDir as $tmp ) {
2534                 if ( $tmp && file_exists( $tmp ) && is_dir( $tmp ) && is_writable( $tmp ) ) {
2535                         return $tmp;
2536                 }
2537         }
2538         return sys_get_temp_dir();
2539 }
2540
2541 /**
2542  * Make directory, and make all parent directories if they don't exist
2543  *
2544  * @param string $dir full path to directory to create
2545  * @param $mode Integer: chmod value to use, default is $wgDirectoryMode
2546  * @param string $caller optional caller param for debugging.
2547  * @throws MWException
2548  * @return bool
2549  */
2550 function wfMkdirParents( $dir, $mode = null, $caller = null ) {
2551         global $wgDirectoryMode;
2552
2553         if ( FileBackend::isStoragePath( $dir ) ) { // sanity
2554                 throw new MWException( __FUNCTION__ . " given storage path '$dir'." );
2555         }
2556
2557         if ( !is_null( $caller ) ) {
2558                 wfDebug( "$caller: called wfMkdirParents($dir)\n" );
2559         }
2560
2561         if ( strval( $dir ) === '' || ( file_exists( $dir ) && is_dir( $dir ) ) ) {
2562                 return true;
2563         }
2564
2565         $dir = str_replace( array( '\\', '/' ), DIRECTORY_SEPARATOR, $dir );
2566
2567         if ( is_null( $mode ) ) {
2568                 $mode = $wgDirectoryMode;
2569         }
2570
2571         // Turn off the normal warning, we're doing our own below
2572         wfSuppressWarnings();
2573         $ok = mkdir( $dir, $mode, true ); // PHP5 <3
2574         wfRestoreWarnings();
2575
2576         if ( !$ok ) {
2577                 //directory may have been created on another request since we last checked
2578                 if ( is_dir( $dir ) ) {
2579                         return true;
2580                 }
2581
2582                 // PHP doesn't report the path in its warning message, so add our own to aid in diagnosis.
2583                 wfLogWarning( sprintf( "failed to mkdir \"%s\" mode 0%o", $dir, $mode ) );
2584         }
2585         return $ok;
2586 }
2587
2588 /**
2589  * Remove a directory and all its content.
2590  * Does not hide error.
2591  */
2592 function wfRecursiveRemoveDir( $dir ) {
2593         wfDebug( __FUNCTION__ . "( $dir )\n" );
2594         // taken from http://de3.php.net/manual/en/function.rmdir.php#98622
2595         if ( is_dir( $dir ) ) {
2596                 $objects = scandir( $dir );
2597                 foreach ( $objects as $object ) {
2598                         if ( $object != "." && $object != ".." ) {
2599                                 if ( filetype( $dir . '/' . $object ) == "dir" ) {
2600                                         wfRecursiveRemoveDir( $dir . '/' . $object );
2601                                 } else {
2602                                         unlink( $dir . '/' . $object );
2603                                 }
2604                         }
2605                 }
2606                 reset( $objects );
2607                 rmdir( $dir );
2608         }
2609 }
2610
2611 /**
2612  * @param $nr Mixed: the number to format
2613  * @param $acc Integer: the number of digits after the decimal point, default 2
2614  * @param $round Boolean: whether or not to round the value, default true
2615  * @return float
2616  */
2617 function wfPercent( $nr, $acc = 2, $round = true ) {
2618         $ret = sprintf( "%.${acc}f", $nr );
2619         return $round ? round( $ret, $acc ) . '%' : "$ret%";
2620 }
2621
2622 /**
2623  * Find out whether or not a mixed variable exists in a string
2624  *
2625  * @deprecated Just use str(i)pos
2626  * @param $needle String
2627  * @param $str String
2628  * @param $insensitive Boolean
2629  * @return Boolean
2630  */
2631 function in_string( $needle, $str, $insensitive = false ) {
2632         wfDeprecated( __METHOD__, '1.21' );
2633         $func = 'strpos';
2634         if ( $insensitive ) {
2635                 $func = 'stripos';
2636         }
2637
2638         return $func( $str, $needle ) !== false;
2639 }
2640
2641 /**
2642  * Safety wrapper around ini_get() for boolean settings.
2643  * The values returned from ini_get() are pre-normalized for settings
2644  * set via php.ini or php_flag/php_admin_flag... but *not*
2645  * for those set via php_value/php_admin_value.
2646  *
2647  * It's fairly common for people to use php_value instead of php_flag,
2648  * which can leave you with an 'off' setting giving a false positive
2649  * for code that just takes the ini_get() return value as a boolean.
2650  *
2651  * To make things extra interesting, setting via php_value accepts
2652  * "true" and "yes" as true, but php.ini and php_flag consider them false. :)
2653  * Unrecognized values go false... again opposite PHP's own coercion
2654  * from string to bool.
2655  *
2656  * Luckily, 'properly' set settings will always come back as '0' or '1',
2657  * so we only have to worry about them and the 'improper' settings.
2658  *
2659  * I frickin' hate PHP... :P
2660  *
2661  * @param $setting String
2662  * @return Bool
2663  */
2664 function wfIniGetBool( $setting ) {
2665         $val = strtolower( ini_get( $setting ) );
2666         // 'on' and 'true' can't have whitespace around them, but '1' can.
2667         return $val == 'on'
2668                 || $val == 'true'
2669                 || $val == 'yes'
2670                 || preg_match( "/^\s*[+-]?0*[1-9]/", $val ); // approx C atoi() function
2671 }
2672
2673 /**
2674  * Windows-compatible version of escapeshellarg()
2675  * Windows doesn't recognise single-quotes in the shell, but the escapeshellarg()
2676  * function puts single quotes in regardless of OS.
2677  *
2678  * Also fixes the locale problems on Linux in PHP 5.2.6+ (bug backported to
2679  * earlier distro releases of PHP)
2680  *
2681  * @param varargs
2682  * @return String
2683  */
2684 function wfEscapeShellArg() {
2685         wfInitShellLocale();
2686
2687         $args = func_get_args();
2688         $first = true;
2689         $retVal = '';
2690         foreach ( $args as $arg ) {
2691                 if ( !$first ) {
2692                         $retVal .= ' ';
2693                 } else {
2694                         $first = false;
2695                 }
2696
2697                 if ( wfIsWindows() ) {
2698                         // Escaping for an MSVC-style command line parser and CMD.EXE
2699                         // @codingStandardsIgnoreStart For long URLs
2700                         // Refs:
2701                         //  * http://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
2702                         //  * http://technet.microsoft.com/en-us/library/cc723564.aspx
2703                         //  * Bug #13518
2704                         //  * CR r63214
2705                         // Double the backslashes before any double quotes. Escape the double quotes.
2706                         // @codingStandardsIgnoreEnd
2707                         $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
2708                         $arg = '';
2709                         $iteration = 0;
2710                         foreach ( $tokens as $token ) {
2711                                 if ( $iteration % 2 == 1 ) {
2712                                         // Delimiter, a double quote preceded by zero or more slashes
2713                                         $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
2714                                 } elseif ( $iteration % 4 == 2 ) {
2715                                         // ^ in $token will be outside quotes, need to be escaped
2716                                         $arg .= str_replace( '^', '^^', $token );
2717                                 } else { // $iteration % 4 == 0
2718                                         // ^ in $token will appear inside double quotes, so leave as is
2719                                         $arg .= $token;
2720                                 }
2721                                 $iteration++;
2722                         }
2723                         // Double the backslashes before the end of the string, because
2724                         // we will soon add a quote
2725                         $m = array();
2726                         if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
2727                                 $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
2728                         }
2729
2730                         // Add surrounding quotes
2731                         $retVal .= '"' . $arg . '"';
2732                 } else {
2733                         $retVal .= escapeshellarg( $arg );
2734                 }
2735         }
2736         return $retVal;
2737 }
2738
2739 /**
2740  * Check if wfShellExec() is effectively disabled via php.ini config
2741  * @return bool|string False or one of (safemode,disabled)
2742  * @since 1.22
2743  */
2744 function wfShellExecDisabled() {
2745         static $disabled = null;
2746         if ( is_null( $disabled ) ) {
2747                 $disabled = false;
2748                 if ( wfIniGetBool( 'safe_mode' ) ) {
2749                         wfDebug( "wfShellExec can't run in safe_mode, PHP's exec functions are too broken.\n" );
2750                         $disabled = 'safemode';
2751                 } else {
2752                         $functions = explode( ',', ini_get( 'disable_functions' ) );
2753                         $functions = array_map( 'trim', $functions );
2754                         $functions = array_map( 'strtolower', $functions );
2755                         if ( in_array( 'proc_open', $functions ) ) {
2756                                 wfDebug( "proc_open is in disabled_functions\n" );
2757                                 $disabled = 'disabled';
2758                         }
2759                 }
2760         }
2761         return $disabled;
2762 }
2763
2764 /**
2765  * Execute a shell command, with time and memory limits mirrored from the PHP
2766  * configuration if supported.
2767  * @param string $cmd Command line, properly escaped for shell.
2768  * @param &$retval null|Mixed optional, will receive the program's exit code.
2769  *                 (non-zero is usually failure). If there is an error from
2770  *                 read, select, or proc_open(), this will be set to -1.
2771  * @param array $environ optional environment variables which should be
2772  *                 added to the executed command environment.
2773  * @param array $limits optional array with limits(filesize, memory, time, walltime)
2774  *                 this overwrites the global wgShellMax* limits.
2775  * @param array $options Array of options:
2776  *    - duplicateStderr: Set this to true to duplicate stderr to stdout,
2777  *      including errors from limit.sh
2778  *
2779  * @return string collected stdout as a string
2780  */
2781 function wfShellExec( $cmd, &$retval = null, $environ = array(),
2782         $limits = array(), $options = array()
2783 ) {
2784         global $IP, $wgMaxShellMemory, $wgMaxShellFileSize, $wgMaxShellTime,
2785                 $wgMaxShellWallClockTime, $wgShellCgroup;
2786
2787         $disabled = wfShellExecDisabled();
2788         if ( $disabled ) {
2789                 $retval = 1;
2790                 return $disabled == 'safemode' ?
2791                         'Unable to run external programs in safe mode.' :
2792                         'Unable to run external programs, proc_open() is disabled.';
2793         }
2794
2795         $includeStderr = isset( $options['duplicateStderr'] ) && $options['duplicateStderr'];
2796
2797         wfInitShellLocale();
2798
2799         $envcmd = '';
2800         foreach ( $environ as $k => $v ) {
2801                 if ( wfIsWindows() ) {
2802                         /* Surrounding a set in quotes (method used by wfEscapeShellArg) makes the quotes themselves
2803                          * appear in the environment variable, so we must use carat escaping as documented in
2804                          * http://technet.microsoft.com/en-us/library/cc723564.aspx
2805                          * Note however that the quote isn't listed there, but is needed, and the parentheses
2806                          * are listed there but doesn't appear to need it.
2807                          */
2808                         $envcmd .= "set $k=" . preg_replace( '/([&|()<>^"])/', '^\\1', $v ) . '&& ';
2809                 } else {
2810                         /* Assume this is a POSIX shell, thus required to accept variable assignments before the command
2811                          * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_01
2812                          */
2813                         $envcmd .= "$k=" . escapeshellarg( $v ) . ' ';
2814                 }
2815         }
2816         $cmd = $envcmd . $cmd;
2817
2818         $useLogPipe = false;
2819         if ( php_uname( 's' ) == 'Linux' ) {
2820                 $time = intval ( isset( $limits['time'] ) ? $limits['time'] : $wgMaxShellTime );
2821                 if ( isset( $limits['walltime'] ) ) {
2822                         $wallTime = intval( $limits['walltime'] );
2823                 } elseif ( isset( $limits['time'] ) ) {
2824                         $wallTime = $time;
2825                 } else {
2826                         $wallTime = intval( $wgMaxShellWallClockTime );
2827                 }
2828                 $mem = intval ( isset( $limits['memory'] ) ? $limits['memory'] : $wgMaxShellMemory );
2829                 $filesize = intval ( isset( $limits['filesize'] ) ? $limits['filesize'] : $wgMaxShellFileSize );
2830
2831                 if ( $time > 0 || $mem > 0 || $filesize > 0 || $wallTime > 0 ) {
2832                         $cmd = '/bin/bash ' . escapeshellarg( "$IP/includes/limit.sh" ) . ' ' .
2833                                 escapeshellarg( $cmd ) . ' ' .
2834                                 escapeshellarg(
2835                                         "MW_INCLUDE_STDERR=" . ( $includeStderr ? '1' : '' ) . ';' .
2836                                         "MW_CPU_LIMIT=$time; " .
2837                                         'MW_CGROUP=' . escapeshellarg( $wgShellCgroup ) . '; ' .
2838                                         "MW_MEM_LIMIT=$mem; " .
2839                                         "MW_FILE_SIZE_LIMIT=$filesize; " .
2840                                         "MW_WALL_CLOCK_LIMIT=$wallTime; " .
2841                                         "MW_USE_LOG_PIPE=yes"
2842                                 );
2843                         $useLogPipe = true;
2844                 } elseif ( $includeStderr ) {
2845                         $cmd .= ' 2>&1';
2846                 }
2847         } elseif ( $includeStderr ) {
2848                 $cmd .= ' 2>&1';
2849         }
2850         wfDebug( "wfShellExec: $cmd\n" );
2851
2852         $desc = array(
2853                 0 => array( 'file', 'php://stdin', 'r' ),
2854                 1 => array( 'pipe', 'w' ),
2855                 2 => array( 'file', 'php://stderr', 'w' ) );
2856         if ( $useLogPipe ) {
2857                 $desc[3] = array( 'pipe', 'w' );
2858         }
2859
2860         # TODO/FIXME: This is a bad hack to workaround an HHVM bug that prevents
2861         # proc_open() from opening stdin/stdout, so use /dev/null *for now*
2862         # See bug 56597 / https://github.com/facebook/hhvm/issues/1247 for more info
2863         if ( wfIsHHVM() ) {
2864                 $desc[0] = array( 'file', '/dev/null', 'r' );
2865                 $desc[2] = array( 'file', '/dev/null', 'w' );
2866         }
2867
2868         $pipes = null;
2869         $proc = proc_open( $cmd, $desc, $pipes );
2870         if ( !$proc ) {
2871                 wfDebugLog( 'exec', "proc_open() failed: $cmd\n" );
2872                 $retval = -1;
2873                 return '';
2874         }
2875         $outBuffer = $logBuffer = '';
2876         $emptyArray = array();
2877         $status = false;
2878         $logMsg = false;
2879
2880         // According to the documentation, it is possible for stream_select()
2881         // to fail due to EINTR. I haven't managed to induce this in testing
2882         // despite sending various signals. If it did happen, the error
2883         // message would take the form:
2884         //
2885         // stream_select(): unable to select [4]: Interrupted system call (max_fd=5)
2886         //
2887         // where [4] is the value of the macro EINTR and "Interrupted system
2888         // call" is string which according to the Linux manual is "possibly"
2889         // localised according to LC_MESSAGES.
2890         $eintr = defined( 'SOCKET_EINTR' ) ? SOCKET_EINTR : 4;
2891         $eintrMessage = "stream_select(): unable to select [$eintr]";
2892
2893         // Build a table mapping resource IDs to pipe FDs to work around a
2894         // PHP 5.3 issue in which stream_select() does not preserve array keys
2895         // <https://bugs.php.net/bug.php?id=53427>.
2896         $fds = array();
2897         foreach ( $pipes as $fd => $pipe ) {
2898                 $fds[(int)$pipe] = $fd;
2899         }
2900
2901         while ( true ) {
2902                 $status = proc_get_status( $proc );
2903                 if ( !$status['running'] ) {
2904                         break;
2905                 }
2906                 $status = false;
2907
2908                 $readyPipes = $pipes;
2909
2910                 // Clear last error
2911                 @trigger_error( '' );
2912                 if ( @stream_select( $readyPipes, $emptyArray, $emptyArray, null ) === false ) {
2913                         $error = error_get_last();
2914                         if ( strncmp( $error['message'], $eintrMessage, strlen( $eintrMessage ) ) == 0 ) {
2915                                 continue;
2916                         } else {
2917                                 trigger_error( $error['message'], E_USER_WARNING );
2918                                 $logMsg = $error['message'];
2919                                 break;
2920                         }
2921                 }
2922                 foreach ( $readyPipes as $pipe ) {
2923                         $block = fread( $pipe, 65536 );
2924                         $fd = $fds[(int)$pipe];
2925                         if ( $block === '' ) {
2926                                 // End of file
2927                                 fclose( $pipes[$fd] );
2928                                 unset( $pipes[$fd] );
2929                                 if ( !$pipes ) {
2930                                         break 2;
2931                                 }
2932                         } elseif ( $block === false ) {
2933                                 // Read error
2934                                 $logMsg = "Error reading from pipe";
2935                                 break 2;
2936                         } elseif ( $fd == 1 ) {
2937                                 // From stdout
2938                                 $outBuffer .= $block;
2939                         } elseif ( $fd == 3 ) {
2940                                 // From log FD
2941                                 $logBuffer .= $block;
2942                                 if ( strpos( $block, "\n" ) !== false ) {
2943                                         $lines = explode( "\n", $logBuffer );
2944                                         $logBuffer = array_pop( $lines );
2945                                         foreach ( $lines as $line ) {
2946                                                 wfDebugLog( 'exec', $line );
2947                                         }
2948                                 }
2949                         }
2950                 }
2951         }
2952
2953         foreach ( $pipes as $pipe ) {
2954                 fclose( $pipe );
2955         }
2956
2957         // Use the status previously collected if possible, since proc_get_status()
2958         // just calls waitpid() which will not return anything useful the second time.
2959         if ( $status === false ) {
2960                 $status = proc_get_status( $proc );
2961         }
2962
2963         if ( $logMsg !== false ) {
2964                 // Read/select error
2965                 $retval = -1;
2966                 proc_close( $proc );
2967         } elseif ( $status['signaled'] ) {
2968                 $logMsg = "Exited with signal {$status['termsig']}";
2969                 $retval = 128 + $status['termsig'];
2970                 proc_close( $proc );
2971         } else {
2972                 if ( $status['running'] ) {
2973                         $retval = proc_close( $proc );
2974                 } else {
2975                         $retval = $status['exitcode'];
2976                         proc_close( $proc );
2977                 }
2978                 if ( $retval == 127 ) {
2979                         $logMsg = "Possibly missing executable file";
2980                 } elseif ( $retval >= 129 && $retval <= 192 ) {
2981                         $logMsg = "Probably exited with signal " . ( $retval - 128 );
2982                 }
2983         }
2984
2985         if ( $logMsg !== false ) {
2986                 wfDebugLog( 'exec', "$logMsg: $cmd\n" );
2987         }
2988
2989         return $outBuffer;
2990 }
2991
2992 /**
2993  * Execute a shell command, returning both stdout and stderr. Convenience
2994  * function, as all the arguments to wfShellExec can become unwieldy.
2995  *
2996  * @note This also includes errors from limit.sh, e.g. if $wgMaxShellFileSize is exceeded.
2997  * @param string $cmd Command line, properly escaped for shell.
2998  * @param &$retval null|Mixed optional, will receive the program's exit code.
2999  *                 (non-zero is usually failure)
3000  * @param array $environ optional environment variables which should be
3001  *                 added to the executed command environment.
3002  * @param array $limits optional array with limits(filesize, memory, time, walltime)
3003  *                 this overwrites the global wgShellMax* limits.
3004  * @return string collected stdout and stderr as a string
3005  */
3006 function wfShellExecWithStderr( $cmd, &$retval = null, $environ = array(), $limits = array() ) {
3007         return wfShellExec( $cmd, $retval, $environ, $limits, array( 'duplicateStderr' => true ) );
3008 }
3009
3010 /**
3011  * Workaround for http://bugs.php.net/bug.php?id=45132
3012  * escapeshellarg() destroys non-ASCII characters if LANG is not a UTF-8 locale
3013  */
3014 function wfInitShellLocale() {
3015         static $done = false;
3016         if ( $done ) {
3017                 return;
3018         }
3019         $done = true;
3020         global $wgShellLocale;
3021         if ( !wfIniGetBool( 'safe_mode' ) ) {
3022                 putenv( "LC_CTYPE=$wgShellLocale" );
3023                 setlocale( LC_CTYPE, $wgShellLocale );
3024         }
3025 }
3026
3027 /**
3028  * Alias to wfShellWikiCmd()
3029  * @see wfShellWikiCmd()
3030  */
3031 function wfShellMaintenanceCmd( $script, array $parameters = array(), array $options = array() ) {
3032         return wfShellWikiCmd( $script, $parameters, $options );
3033 }
3034
3035 /**
3036  * Generate a shell-escaped command line string to run a MediaWiki cli script.
3037  * Note that $parameters should be a flat array and an option with an argument
3038  * should consist of two consecutive items in the array (do not use "--option value").
3039  * @param string $script MediaWiki cli script path
3040  * @param array $parameters Arguments and options to the script
3041  * @param array $options Associative array of options:
3042  *              'php': The path to the php executable
3043  *              'wrapper': Path to a PHP wrapper to handle the maintenance script
3044  * @return Array
3045  */
3046 function wfShellWikiCmd( $script, array $parameters = array(), array $options = array() ) {
3047         global $wgPhpCli;
3048         // Give site config file a chance to run the script in a wrapper.
3049         // The caller may likely want to call wfBasename() on $script.
3050         wfRunHooks( 'wfShellWikiCmd', array( &$script, &$parameters, &$options ) );
3051         $cmd = isset( $options['php'] ) ? array( $options['php'] ) : array( $wgPhpCli );
3052         if ( isset( $options['wrapper'] ) ) {
3053                 $cmd[] = $options['wrapper'];
3054         }
3055         $cmd[] = $script;
3056         // Escape each parameter for shell
3057         return implode( " ", array_map( 'wfEscapeShellArg', array_merge( $cmd, $parameters ) ) );
3058 }
3059
3060 /**
3061  * wfMerge attempts to merge differences between three texts.
3062  * Returns true for a clean merge and false for failure or a conflict.
3063  *
3064  * @param $old String
3065  * @param $mine String
3066  * @param $yours String
3067  * @param $result String
3068  * @return Bool
3069  */
3070 function wfMerge( $old, $mine, $yours, &$result ) {
3071         global $wgDiff3;
3072
3073         # This check may also protect against code injection in
3074         # case of broken installations.
3075         wfSuppressWarnings();
3076         $haveDiff3 = $wgDiff3 && file_exists( $wgDiff3 );
3077         wfRestoreWarnings();
3078
3079         if ( !$haveDiff3 ) {
3080                 wfDebug( "diff3 not found\n" );
3081                 return false;
3082         }
3083
3084         # Make temporary files
3085         $td = wfTempDir();
3086         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
3087         $mytextFile = fopen( $mytextName = tempnam( $td, 'merge-mine-' ), 'w' );
3088         $yourtextFile = fopen( $yourtextName = tempnam( $td, 'merge-your-' ), 'w' );
3089
3090         # NOTE: diff3 issues a warning to stderr if any of the files does not end with
3091         #       a newline character. To avoid this, we normalize the trailing whitespace before
3092         #       creating the diff.
3093
3094         fwrite( $oldtextFile, rtrim( $old ) . "\n" );
3095         fclose( $oldtextFile );
3096         fwrite( $mytextFile, rtrim( $mine ) . "\n" );
3097         fclose( $mytextFile );
3098         fwrite( $yourtextFile, rtrim( $yours ) . "\n" );
3099         fclose( $yourtextFile );
3100
3101         # Check for a conflict
3102         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a --overlap-only ' .
3103                 wfEscapeShellArg( $mytextName ) . ' ' .
3104                 wfEscapeShellArg( $oldtextName ) . ' ' .
3105                 wfEscapeShellArg( $yourtextName );
3106         $handle = popen( $cmd, 'r' );
3107
3108         if ( fgets( $handle, 1024 ) ) {
3109                 $conflict = true;
3110         } else {
3111                 $conflict = false;
3112         }
3113         pclose( $handle );
3114
3115         # Merge differences
3116         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a -e --merge ' .
3117                 wfEscapeShellArg( $mytextName, $oldtextName, $yourtextName );
3118         $handle = popen( $cmd, 'r' );
3119         $result = '';
3120         do {
3121                 $data = fread( $handle, 8192 );
3122                 if ( strlen( $data ) == 0 ) {
3123                         break;
3124                 }
3125                 $result .= $data;
3126         } while ( true );
3127         pclose( $handle );
3128         unlink( $mytextName );
3129         unlink( $oldtextName );
3130         unlink( $yourtextName );
3131
3132         if ( $result === '' && $old !== '' && !$conflict ) {
3133                 wfDebug( "Unexpected null result from diff3. Command: $cmd\n" );
3134                 $conflict = true;
3135         }
3136         return !$conflict;
3137 }
3138
3139 /**
3140  * Returns unified plain-text diff of two texts.
3141  * Useful for machine processing of diffs.
3142  *
3143  * @param string $before the text before the changes.
3144  * @param string $after the text after the changes.
3145  * @param string $params command-line options for the diff command.
3146  * @return String: unified diff of $before and $after
3147  */
3148 function wfDiff( $before, $after, $params = '-u' ) {
3149         if ( $before == $after ) {
3150                 return '';
3151         }
3152
3153         global $wgDiff;
3154         wfSuppressWarnings();
3155         $haveDiff = $wgDiff && file_exists( $wgDiff );
3156         wfRestoreWarnings();
3157
3158         # This check may also protect against code injection in
3159         # case of broken installations.
3160         if ( !$haveDiff ) {
3161                 wfDebug( "diff executable not found\n" );
3162                 $diffs = new Diff( explode( "\n", $before ), explode( "\n", $after ) );
3163                 $format = new UnifiedDiffFormatter();
3164                 return $format->format( $diffs );
3165         }
3166
3167         # Make temporary files
3168         $td = wfTempDir();
3169         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
3170         $newtextFile = fopen( $newtextName = tempnam( $td, 'merge-your-' ), 'w' );
3171
3172         fwrite( $oldtextFile, $before );
3173         fclose( $oldtextFile );
3174         fwrite( $newtextFile, $after );
3175         fclose( $newtextFile );
3176
3177         // Get the diff of the two files
3178         $cmd = "$wgDiff " . $params . ' ' . wfEscapeShellArg( $oldtextName, $newtextName );
3179
3180         $h = popen( $cmd, 'r' );
3181
3182         $diff = '';
3183
3184         do {
3185                 $data = fread( $h, 8192 );
3186                 if ( strlen( $data ) == 0 ) {
3187                         break;
3188                 }
3189                 $diff .= $data;
3190         } while ( true );
3191
3192         // Clean up
3193         pclose( $h );
3194         unlink( $oldtextName );
3195         unlink( $newtextName );
3196
3197         // Kill the --- and +++ lines. They're not useful.
3198         $diff_lines = explode( "\n", $diff );
3199         if ( strpos( $diff_lines[0], '---' ) === 0 ) {
3200                 unset( $diff_lines[0] );
3201         }
3202         if ( strpos( $diff_lines[1], '+++' ) === 0 ) {
3203                 unset( $diff_lines[1] );
3204         }
3205
3206         $diff = implode( "\n", $diff_lines );
3207
3208         return $diff;
3209 }
3210
3211 /**
3212  * This function works like "use VERSION" in Perl, the program will die with a
3213  * backtrace if the current version of PHP is less than the version provided
3214  *
3215  * This is useful for extensions which due to their nature are not kept in sync
3216  * with releases, and might depend on other versions of PHP than the main code
3217  *
3218  * Note: PHP might die due to parsing errors in some cases before it ever
3219  *       manages to call this function, such is life
3220  *
3221  * @see perldoc -f use
3222  *
3223  * @param $req_ver Mixed: the version to check, can be a string, an integer, or
3224  *                 a float
3225  * @throws MWException
3226  */
3227 function wfUsePHP( $req_ver ) {
3228         $php_ver = PHP_VERSION;
3229
3230         if ( version_compare( $php_ver, (string)$req_ver, '<' ) ) {
3231                 throw new MWException( "PHP $req_ver required--this is only $php_ver" );
3232         }
3233 }
3234
3235 /**
3236  * This function works like "use VERSION" in Perl except it checks the version
3237  * of MediaWiki, the program will die with a backtrace if the current version
3238  * of MediaWiki is less than the version provided.
3239  *
3240  * This is useful for extensions which due to their nature are not kept in sync
3241  * with releases
3242  *
3243  * Note: Due to the behavior of PHP's version_compare() which is used in this
3244  * fuction, if you want to allow the 'wmf' development versions add a 'c' (or
3245  * any single letter other than 'a', 'b' or 'p') as a post-fix to your
3246  * targeted version number. For example if you wanted to allow any variation
3247  * of 1.22 use `wfUseMW( '1.22c' )`. Using an 'a' or 'b' instead of 'c' will
3248  * not result in the same comparison due to the internal logic of
3249  * version_compare().
3250  *
3251  * @see perldoc -f use
3252  *
3253  * @param $req_ver Mixed: the version to check, can be a string, an integer, or
3254  *                 a float
3255  * @throws MWException
3256  */
3257 function wfUseMW( $req_ver ) {
3258         global $wgVersion;
3259
3260         if ( version_compare( $wgVersion, (string)$req_ver, '<' ) ) {
3261                 throw new MWException( "MediaWiki $req_ver required--this is only $wgVersion" );
3262         }
3263 }
3264
3265 /**
3266  * Return the final portion of a pathname.
3267  * Reimplemented because PHP5's "basename()" is buggy with multibyte text.
3268  * http://bugs.php.net/bug.php?id=33898
3269  *
3270  * PHP's basename() only considers '\' a pathchar on Windows and Netware.
3271  * We'll consider it so always, as we don't want '\s' in our Unix paths either.
3272  *
3273  * @param $path String
3274  * @param string $suffix to remove if present
3275  * @return String
3276  */
3277 function wfBaseName( $path, $suffix = '' ) {
3278         if ( $suffix == '' ) {
3279                 $encSuffix = '';
3280         } else {
3281                 $encSuffix = '(?:' . preg_quote( $suffix, '#' ) . ')?';
3282         }
3283
3284         $matches = array();
3285         if ( preg_match( "#([^/\\\\]*?){$encSuffix}[/\\\\]*$#", $path, $matches ) ) {
3286                 return $matches[1];
3287         } else {
3288                 return '';
3289         }
3290 }
3291
3292 /**
3293  * Generate a relative path name to the given file.
3294  * May explode on non-matching case-insensitive paths,
3295  * funky symlinks, etc.
3296  *
3297  * @param string $path absolute destination path including target filename
3298  * @param string $from Absolute source path, directory only
3299  * @return String
3300  */
3301 function wfRelativePath( $path, $from ) {
3302         // Normalize mixed input on Windows...
3303         $path = str_replace( '/', DIRECTORY_SEPARATOR, $path );
3304         $from = str_replace( '/', DIRECTORY_SEPARATOR, $from );
3305
3306         // Trim trailing slashes -- fix for drive root
3307         $path = rtrim( $path, DIRECTORY_SEPARATOR );
3308         $from = rtrim( $from, DIRECTORY_SEPARATOR );
3309
3310         $pieces = explode( DIRECTORY_SEPARATOR, dirname( $path ) );
3311         $against = explode( DIRECTORY_SEPARATOR, $from );
3312
3313         if ( $pieces[0] !== $against[0] ) {
3314                 // Non-matching Windows drive letters?
3315                 // Return a full path.
3316                 return $path;
3317         }
3318
3319         // Trim off common prefix
3320         while ( count( $pieces ) && count( $against )
3321                 && $pieces[0] == $against[0] ) {
3322                 array_shift( $pieces );
3323                 array_shift( $against );
3324         }
3325
3326         // relative dots to bump us to the parent
3327         while ( count( $against ) ) {
3328                 array_unshift( $pieces, '..' );
3329                 array_shift( $against );
3330         }
3331
3332         array_push( $pieces, wfBaseName( $path ) );
3333
3334         return implode( DIRECTORY_SEPARATOR, $pieces );
3335 }
3336
3337 /**
3338  * Convert an arbitrarily-long digit string from one numeric base
3339  * to another, optionally zero-padding to a minimum column width.
3340  *
3341  * Supports base 2 through 36; digit values 10-36 are represented
3342  * as lowercase letters a-z. Input is case-insensitive.
3343  *
3344  * @param string $input Input number
3345  * @param int $sourceBase Base of the input number
3346  * @param int $destBase Desired base of the output
3347  * @param int $pad Minimum number of digits in the output (pad with zeroes)
3348  * @param bool $lowercase Whether to output in lowercase or uppercase
3349  * @param string $engine Either "gmp", "bcmath", or "php"
3350  * @return string|bool The output number as a string, or false on error
3351  */
3352 function wfBaseConvert( $input, $sourceBase, $destBase, $pad = 1,
3353         $lowercase = true, $engine = 'auto'
3354 ) {
3355         $input = (string)$input;
3356         if (
3357                 $sourceBase < 2 ||
3358                 $sourceBase > 36 ||
3359                 $destBase < 2 ||
3360                 $destBase > 36 ||
3361                 $sourceBase != (int)$sourceBase ||
3362                 $destBase != (int)$destBase ||
3363                 $pad != (int)$pad ||
3364                 !preg_match(
3365                         "/^[" . substr( '0123456789abcdefghijklmnopqrstuvwxyz', 0, $sourceBase ) . "]+$/i",
3366                         $input
3367                 )
3368         ) {
3369                 return false;
3370         }
3371
3372         static $baseChars = array(
3373                 10 => 'a', 11 => 'b', 12 => 'c', 13 => 'd', 14 => 'e', 15 => 'f',
3374                 16 => 'g', 17 => 'h', 18 => 'i', 19 => 'j', 20 => 'k', 21 => 'l',
3375                 22 => 'm', 23 => 'n', 24 => 'o', 25 => 'p', 26 => 'q', 27 => 'r',
3376                 28 => 's', 29 => 't', 30 => 'u', 31 => 'v', 32 => 'w', 33 => 'x',
3377                 34 => 'y', 35 => 'z',
3378
3379                 '0' => 0,  '1' => 1,  '2' => 2,  '3' => 3,  '4' => 4,  '5' => 5,
3380                 '6' => 6,  '7' => 7,  '8' => 8,  '9' => 9,  'a' => 10, 'b' => 11,
3381                 'c' => 12, 'd' => 13, 'e' => 14, 'f' => 15, 'g' => 16, 'h' => 17,
3382                 'i' => 18, 'j' => 19, 'k' => 20, 'l' => 21, 'm' => 22, 'n' => 23,
3383                 'o' => 24, 'p' => 25, 'q' => 26, 'r' => 27, 's' => 28, 't' => 29,
3384                 'u' => 30, 'v' => 31, 'w' => 32, 'x' => 33, 'y' => 34, 'z' => 35
3385         );
3386
3387         if ( extension_loaded( 'gmp' ) && ( $engine == 'auto' || $engine == 'gmp' ) ) {
3388                 $result = gmp_strval( gmp_init( $input, $sourceBase ), $destBase );
3389         } elseif ( extension_loaded( 'bcmath' ) && ( $engine == 'auto' || $engine == 'bcmath' ) ) {
3390                 $decimal = '0';
3391                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3392                         $decimal = bcmul( $decimal, $sourceBase );
3393                         $decimal = bcadd( $decimal, $baseChars[$char] );
3394                 }
3395
3396                 for ( $result = ''; bccomp( $decimal, 0 ); $decimal = bcdiv( $decimal, $destBase, 0 ) ) {
3397                         $result .= $baseChars[bcmod( $decimal, $destBase )];
3398                 }
3399
3400                 $result = strrev( $result );
3401         } else {
3402                 $inDigits = array();
3403                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3404                         $inDigits[] = $baseChars[$char];
3405                 }
3406
3407                 // Iterate over the input, modulo-ing out an output digit
3408                 // at a time until input is gone.
3409                 $result = '';
3410                 while ( $inDigits ) {
3411                         $work = 0;
3412                         $workDigits = array();
3413
3414                         // Long division...
3415                         foreach ( $inDigits as $digit ) {
3416                                 $work *= $sourceBase;
3417                                 $work += $digit;
3418
3419                                 if ( $workDigits || $work >= $destBase ) {
3420                                         $workDigits[] = (int)( $work / $destBase );
3421                                 }
3422                                 $work %= $destBase;
3423                         }
3424
3425                         // All that division leaves us with a remainder,
3426                         // which is conveniently our next output digit.
3427                         $result .= $baseChars[$work];
3428
3429                         // And we continue!
3430                         $inDigits = $workDigits;
3431                 }
3432
3433                 $result = strrev( $result );
3434         }
3435
3436         if ( !$lowercase ) {
3437                 $result = strtoupper( $result );
3438         }
3439
3440         return str_pad( $result, $pad, '0', STR_PAD_LEFT );
3441 }
3442
3443 /**
3444  * @return bool
3445  */
3446 function wfHttpOnlySafe() {
3447         global $wgHttpOnlyBlacklist;
3448
3449         if ( isset( $_SERVER['HTTP_USER_AGENT'] ) ) {
3450                 foreach ( $wgHttpOnlyBlacklist as $regex ) {
3451                         if ( preg_match( $regex, $_SERVER['HTTP_USER_AGENT'] ) ) {
3452                                 return false;
3453                         }
3454                 }
3455         }
3456
3457         return true;
3458 }
3459
3460 /**
3461  * Check if there is sufficient entropy in php's built-in session generation
3462  * @return bool true = there is sufficient entropy
3463  */
3464 function wfCheckEntropy() {
3465         return (
3466                         ( wfIsWindows() && version_compare( PHP_VERSION, '5.3.3', '>=' ) )
3467                         || ini_get( 'session.entropy_file' )
3468                 )
3469                 && intval( ini_get( 'session.entropy_length' ) ) >= 32;
3470 }
3471
3472 /**
3473  * Override session_id before session startup if php's built-in
3474  * session generation code is not secure.
3475  */
3476 function wfFixSessionID() {
3477         // If the cookie or session id is already set we already have a session and should abort
3478         if ( isset( $_COOKIE[session_name()] ) || session_id() ) {
3479                 return;
3480         }
3481
3482         // PHP's built-in session entropy is enabled if:
3483         // - entropy_file is set or you're on Windows with php 5.3.3+
3484         // - AND entropy_length is > 0
3485         // We treat it as disabled if it doesn't have an entropy length of at least 32
3486         $entropyEnabled = wfCheckEntropy();
3487
3488         // If built-in entropy is not enabled or not sufficient override PHP's
3489         // built in session id generation code
3490         if ( !$entropyEnabled ) {
3491                 wfDebug( __METHOD__ . ": PHP's built in entropy is disabled or not sufficient, " .
3492                         "overriding session id generation using our cryptrand source.\n" );
3493                 session_id( MWCryptRand::generateHex( 32 ) );
3494         }
3495 }
3496
3497 /**
3498  * Reset the session_id
3499  * @since 1.22
3500  */
3501 function wfResetSessionID() {
3502         global $wgCookieSecure;
3503         $oldSessionId = session_id();
3504         $cookieParams = session_get_cookie_params();
3505         if ( wfCheckEntropy() && $wgCookieSecure == $cookieParams['secure'] ) {
3506                 session_regenerate_id( false );
3507         } else {
3508                 $tmp = $_SESSION;
3509                 session_destroy();
3510                 wfSetupSession( MWCryptRand::generateHex( 32 ) );
3511                 $_SESSION = $tmp;
3512         }
3513         $newSessionId = session_id();
3514         wfRunHooks( 'ResetSessionID', array( $oldSessionId, $newSessionId ) );
3515 }
3516
3517
3518 /**
3519  * Initialise php session
3520  *
3521  * @param $sessionId Bool
3522  */
3523 function wfSetupSession( $sessionId = false ) {
3524         global $wgSessionsInMemcached, $wgSessionsInObjectCache, $wgCookiePath, $wgCookieDomain,
3525                         $wgCookieSecure, $wgCookieHttpOnly, $wgSessionHandler;
3526         if ( $wgSessionsInObjectCache || $wgSessionsInMemcached ) {
3527                 ObjectCacheSessionHandler::install();
3528         } elseif ( $wgSessionHandler && $wgSessionHandler != ini_get( 'session.save_handler' ) ) {
3529                 # Only set this if $wgSessionHandler isn't null and session.save_handler
3530                 # hasn't already been set to the desired value (that causes errors)
3531                 ini_set( 'session.save_handler', $wgSessionHandler );
3532         }
3533         $httpOnlySafe = wfHttpOnlySafe() && $wgCookieHttpOnly;
3534         wfDebugLog( 'cookie',
3535                 'session_set_cookie_params: "' . implode( '", "',
3536                         array(
3537                                 0,
3538                                 $wgCookiePath,
3539                                 $wgCookieDomain,
3540                                 $wgCookieSecure,
3541                                 $httpOnlySafe ) ) . '"' );
3542         session_set_cookie_params( 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $httpOnlySafe );
3543         session_cache_limiter( 'private, must-revalidate' );
3544         if ( $sessionId ) {
3545                 session_id( $sessionId );
3546         } else {
3547                 wfFixSessionID();
3548         }
3549         wfSuppressWarnings();
3550         session_start();
3551         wfRestoreWarnings();
3552 }
3553
3554 /**
3555  * Get an object from the precompiled serialized directory
3556  *
3557  * @param $name String
3558  * @return Mixed: the variable on success, false on failure
3559  */
3560 function wfGetPrecompiledData( $name ) {
3561         global $IP;
3562
3563         $file = "$IP/serialized/$name";
3564         if ( file_exists( $file ) ) {
3565                 $blob = file_get_contents( $file );
3566                 if ( $blob ) {
3567                         return unserialize( $blob );
3568                 }
3569         }
3570         return false;
3571 }
3572
3573 /**
3574  * Get a cache key
3575  *
3576  * @param varargs
3577  * @return String
3578  */
3579 function wfMemcKey( /*... */ ) {
3580         global $wgCachePrefix;
3581         $prefix = $wgCachePrefix === false ? wfWikiID() : $wgCachePrefix;
3582         $args = func_get_args();
3583         $key = $prefix . ':' . implode( ':', $args );
3584         $key = str_replace( ' ', '_', $key );
3585         return $key;
3586 }
3587
3588 /**
3589  * Get a cache key for a foreign DB
3590  *
3591  * @param $db String
3592  * @param $prefix String
3593  * @param varargs String
3594  * @return String
3595  */
3596 function wfForeignMemcKey( $db, $prefix /*, ... */ ) {
3597         $args = array_slice( func_get_args(), 2 );
3598         if ( $prefix ) {
3599                 $key = "$db-$prefix:" . implode( ':', $args );
3600         } else {
3601                 $key = $db . ':' . implode( ':', $args );
3602         }
3603         return str_replace( ' ', '_', $key );
3604 }
3605
3606 /**
3607  * Get an ASCII string identifying this wiki
3608  * This is used as a prefix in memcached keys
3609  *
3610  * @return String
3611  */
3612 function wfWikiID() {
3613         global $wgDBprefix, $wgDBname;
3614         if ( $wgDBprefix ) {
3615                 return "$wgDBname-$wgDBprefix";
3616         } else {
3617                 return $wgDBname;
3618         }
3619 }
3620
3621 /**
3622  * Split a wiki ID into DB name and table prefix
3623  *
3624  * @param $wiki String
3625  *
3626  * @return array
3627  */
3628 function wfSplitWikiID( $wiki ) {
3629         $bits = explode( '-', $wiki, 2 );
3630         if ( count( $bits ) < 2 ) {
3631                 $bits[] = '';
3632         }
3633         return $bits;
3634 }
3635
3636 /**
3637  * Get a Database object.
3638  *
3639  * @param $db Integer: index of the connection to get. May be DB_MASTER for the
3640  *            master (for write queries), DB_SLAVE for potentially lagged read
3641  *            queries, or an integer >= 0 for a particular server.
3642  *
3643  * @param $groups Mixed: query groups. An array of group names that this query
3644  *                belongs to. May contain a single string if the query is only
3645  *                in one group.
3646  *
3647  * @param string $wiki the wiki ID, or false for the current wiki
3648  *
3649  * Note: multiple calls to wfGetDB(DB_SLAVE) during the course of one request
3650  * will always return the same object, unless the underlying connection or load
3651  * balancer is manually destroyed.
3652  *
3653  * Note 2: use $this->getDB() in maintenance scripts that may be invoked by
3654  * updater to ensure that a proper database is being updated.
3655  *
3656  * @return DatabaseBase
3657  */
3658 function &wfGetDB( $db, $groups = array(), $wiki = false ) {
3659         return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
3660 }
3661
3662 /**
3663  * Get a load balancer object.
3664  *
3665  * @param string $wiki wiki ID, or false for the current wiki
3666  * @return LoadBalancer
3667  */
3668 function wfGetLB( $wiki = false ) {
3669         return wfGetLBFactory()->getMainLB( $wiki );
3670 }
3671
3672 /**
3673  * Get the load balancer factory object
3674  *
3675  * @return LBFactory
3676  */
3677 function &wfGetLBFactory() {
3678         return LBFactory::singleton();
3679 }
3680
3681 /**
3682  * Find a file.
3683  * Shortcut for RepoGroup::singleton()->findFile()
3684  *
3685  * @param string $title or Title object
3686  * @param array $options Associative array of options:
3687  *     time:           requested time for an archived image, or false for the
3688  *                     current version. An image object will be returned which was
3689  *                     created at the specified time.
3690  *
3691  *     ignoreRedirect: If true, do not follow file redirects
3692  *
3693  *     private:        If true, return restricted (deleted) files if the current
3694  *                     user is allowed to view them. Otherwise, such files will not
3695  *                     be found.
3696  *
3697  *     bypassCache:    If true, do not use the process-local cache of File objects
3698  *
3699  * @return File, or false if the file does not exist
3700  */
3701 function wfFindFile( $title, $options = array() ) {
3702         return RepoGroup::singleton()->findFile( $title, $options );
3703 }
3704
3705 /**
3706  * Get an object referring to a locally registered file.
3707  * Returns a valid placeholder object if the file does not exist.
3708  *
3709  * @param $title Title|String
3710  * @return LocalFile|null A File, or null if passed an invalid Title
3711  */
3712 function wfLocalFile( $title ) {
3713         return RepoGroup::singleton()->getLocalRepo()->newFile( $title );
3714 }
3715
3716 /**
3717  * Stream a file to the browser. Back-compat alias for StreamFile::stream()
3718  * @deprecated since 1.19
3719  */
3720 function wfStreamFile( $fname, $headers = array() ) {
3721         wfDeprecated( __FUNCTION__, '1.19' );
3722         StreamFile::stream( $fname, $headers );
3723 }
3724
3725 /**
3726  * Should low-performance queries be disabled?
3727  *
3728  * @return Boolean
3729  * @codeCoverageIgnore
3730  */
3731 function wfQueriesMustScale() {
3732         global $wgMiserMode;
3733         return $wgMiserMode
3734                 || ( SiteStats::pages() > 100000
3735                 && SiteStats::edits() > 1000000
3736                 && SiteStats::users() > 10000 );
3737 }
3738
3739 /**
3740  * Get the path to a specified script file, respecting file
3741  * extensions; this is a wrapper around $wgScriptExtension etc.
3742  * except for 'index' and 'load' which use $wgScript/$wgLoadScript
3743  *
3744  * @param string $script script filename, sans extension
3745  * @return String
3746  */
3747 function wfScript( $script = 'index' ) {
3748         global $wgScriptPath, $wgScriptExtension, $wgScript, $wgLoadScript;
3749         if ( $script === 'index' ) {
3750                 return $wgScript;
3751         } elseif ( $script === 'load' ) {
3752                 return $wgLoadScript;
3753         } else {
3754                 return "{$wgScriptPath}/{$script}{$wgScriptExtension}";
3755         }
3756 }
3757
3758 /**
3759  * Get the script URL.
3760  *
3761  * @return string script URL
3762  */
3763 function wfGetScriptUrl() {
3764         if ( isset( $_SERVER['SCRIPT_NAME'] ) ) {
3765                 #
3766                 # as it was called, minus the query string.
3767                 #
3768                 # Some sites use Apache rewrite rules to handle subdomains,
3769                 # and have PHP set up in a weird way that causes PHP_SELF
3770                 # to contain the rewritten URL instead of the one that the
3771                 # outside world sees.
3772                 #
3773                 # If in this mode, use SCRIPT_URL instead, which mod_rewrite
3774                 # provides containing the "before" URL.
3775                 return $_SERVER['SCRIPT_NAME'];
3776         } else {
3777                 return $_SERVER['URL'];
3778         }
3779 }
3780
3781 /**
3782  * Convenience function converts boolean values into "true"
3783  * or "false" (string) values
3784  *
3785  * @param $value Boolean
3786  * @return String
3787  */
3788 function wfBoolToStr( $value ) {
3789         return $value ? 'true' : 'false';
3790 }
3791
3792 /**
3793  * Get a platform-independent path to the null file, e.g. /dev/null
3794  *
3795  * @return string
3796  */
3797 function wfGetNull() {
3798         return wfIsWindows() ? 'NUL' : '/dev/null';
3799 }
3800
3801 /**
3802  * Modern version of wfWaitForSlaves(). Instead of looking at replication lag
3803  * and waiting for it to go down, this waits for the slaves to catch up to the
3804  * master position. Use this when updating very large numbers of rows, as
3805  * in maintenance scripts, to avoid causing too much lag.  Of course, this is
3806  * a no-op if there are no slaves.
3807  *
3808  * @param int|bool $maxLag (deprecated)
3809  * @param mixed $wiki Wiki identifier accepted by wfGetLB
3810  * @param string|bool $cluster Cluster name accepted by LBFactory. Default: false.
3811  */
3812 function wfWaitForSlaves( $maxLag = false, $wiki = false, $cluster = false ) {
3813         if( $cluster !== false ) {
3814                 $lb = wfGetLBFactory()->getExternalLB( $cluster );
3815         } else {
3816                 $lb = wfGetLB( $wiki );
3817         }
3818
3819         // bug 27975 - Don't try to wait for slaves if there are none
3820         // Prevents permission error when getting master position
3821         if ( $lb->getServerCount() > 1 ) {
3822                 $dbw = $lb->getConnection( DB_MASTER, array(), $wiki );
3823                 $pos = $dbw->getMasterPos();
3824                 // The DBMS may not support getMasterPos() or the whole
3825                 // load balancer might be fake (e.g. $wgAllDBsAreLocalhost).
3826                 if ( $pos !== false ) {
3827                         $lb->waitForAll( $pos );
3828                 }
3829         }
3830 }
3831
3832 /**
3833  * Count down from $n to zero on the terminal, with a one-second pause
3834  * between showing each number. For use in command-line scripts.
3835  * @codeCoverageIgnore
3836  * @param $n int
3837  */
3838 function wfCountDown( $n ) {
3839         for ( $i = $n; $i >= 0; $i-- ) {
3840                 if ( $i != $n ) {
3841                         echo str_repeat( "\x08", strlen( $i + 1 ) );
3842                 }
3843                 echo $i;
3844                 flush();
3845                 if ( $i ) {
3846                         sleep( 1 );
3847                 }
3848         }
3849         echo "\n";
3850 }
3851
3852 /**
3853  * Generate a random 32-character hexadecimal token.
3854  * @param $salt Mixed: some sort of salt, if necessary, to add to random
3855  *              characters before hashing.
3856  * @return string
3857  * @codeCoverageIgnore
3858  * @deprecated since 1.20; Please use MWCryptRand for security purposes and
3859  * wfRandomString for pseudo-random strings
3860  * @warning This method is NOT secure. Additionally it has many callers that
3861  * use it for pseudo-random purposes.
3862  */
3863 function wfGenerateToken( $salt = '' ) {
3864         wfDeprecated( __METHOD__, '1.20' );
3865         $salt = serialize( $salt );
3866         return md5( mt_rand( 0, 0x7fffffff ) . $salt );
3867 }
3868
3869 /**
3870  * Replace all invalid characters with -
3871  * Additional characters can be defined in $wgIllegalFileChars (see bug 20489)
3872  * By default, $wgIllegalFileChars = ':'
3873  *
3874  * @param $name Mixed: filename to process
3875  * @return String
3876  */
3877 function wfStripIllegalFilenameChars( $name ) {
3878         global $wgIllegalFileChars;
3879         $illegalFileChars = $wgIllegalFileChars ? "|[" . $wgIllegalFileChars . "]" : '';
3880         $name = wfBaseName( $name );
3881         $name = preg_replace(
3882                 "/[^" . Title::legalChars() . "]" . $illegalFileChars . "/",
3883                 '-',
3884                 $name
3885         );
3886         return $name;
3887 }
3888
3889 /**
3890  * Set PHP's memory limit to the larger of php.ini or $wgMemoryLimit;
3891  *
3892  * @return Integer value memory was set to.
3893  */
3894 function wfMemoryLimit() {
3895         global $wgMemoryLimit;
3896         $memlimit = wfShorthandToInteger( ini_get( 'memory_limit' ) );
3897         if ( $memlimit != -1 ) {
3898                 $conflimit = wfShorthandToInteger( $wgMemoryLimit );
3899                 if ( $conflimit == -1 ) {
3900                         wfDebug( "Removing PHP's memory limit\n" );
3901                         wfSuppressWarnings();
3902                         ini_set( 'memory_limit', $conflimit );
3903                         wfRestoreWarnings();
3904                         return $conflimit;
3905                 } elseif ( $conflimit > $memlimit ) {
3906                         wfDebug( "Raising PHP's memory limit to $conflimit bytes\n" );
3907                         wfSuppressWarnings();
3908                         ini_set( 'memory_limit', $conflimit );
3909                         wfRestoreWarnings();
3910                         return $conflimit;
3911                 }
3912         }
3913         return $memlimit;
3914 }
3915
3916 /**
3917  * Converts shorthand byte notation to integer form
3918  *
3919  * @param $string String
3920  * @return Integer
3921  */
3922 function wfShorthandToInteger( $string = '' ) {
3923         $string = trim( $string );
3924         if ( $string === '' ) {
3925                 return -1;
3926         }
3927         $last = $string[strlen( $string ) - 1];
3928         $val = intval( $string );
3929         switch ( $last ) {
3930                 case 'g':
3931                 case 'G':
3932                         $val *= 1024;
3933                         // break intentionally missing
3934                 case 'm':
3935                 case 'M':
3936                         $val *= 1024;
3937                         // break intentionally missing
3938                 case 'k':
3939                 case 'K':
3940                         $val *= 1024;
3941         }
3942
3943         return $val;
3944 }
3945
3946 /**
3947  * Get the normalised IETF language tag
3948  * See unit test for examples.
3949  *
3950  * @param string $code The language code.
3951  * @return String: The language code which complying with BCP 47 standards.
3952  */
3953 function wfBCP47( $code ) {
3954         $codeSegment = explode( '-', $code );
3955         $codeBCP = array();
3956         foreach ( $codeSegment as $segNo => $seg ) {
3957                 // when previous segment is x, it is a private segment and should be lc
3958                 if ( $segNo > 0 && strtolower( $codeSegment[( $segNo - 1 )] ) == 'x' ) {
3959                         $codeBCP[$segNo] = strtolower( $seg );
3960                 // ISO 3166 country code
3961                 } elseif ( ( strlen( $seg ) == 2 ) && ( $segNo > 0 ) ) {
3962                         $codeBCP[$segNo] = strtoupper( $seg );
3963                 // ISO 15924 script code
3964                 } elseif ( ( strlen( $seg ) == 4 ) && ( $segNo > 0 ) ) {
3965                         $codeBCP[$segNo] = ucfirst( strtolower( $seg ) );
3966                 // Use lowercase for other cases
3967                 } else {
3968                         $codeBCP[$segNo] = strtolower( $seg );
3969                 }
3970         }
3971         $langCode = implode( '-', $codeBCP );
3972         return $langCode;
3973 }
3974
3975 /**
3976  * Get a cache object.
3977  *
3978  * @param $inputType integer Cache type, one the the CACHE_* constants.
3979  * @return BagOStuff
3980  */
3981 function wfGetCache( $inputType ) {
3982         return ObjectCache::getInstance( $inputType );
3983 }
3984
3985 /**
3986  * Get the main cache object
3987  *
3988  * @return BagOStuff
3989  */
3990 function wfGetMainCache() {
3991         global $wgMainCacheType;
3992         return ObjectCache::getInstance( $wgMainCacheType );
3993 }
3994
3995 /**
3996  * Get the cache object used by the message cache
3997  *
3998  * @return BagOStuff
3999  */
4000 function wfGetMessageCacheStorage() {
4001         global $wgMessageCacheType;
4002         return ObjectCache::getInstance( $wgMessageCacheType );
4003 }
4004
4005 /**
4006  * Get the cache object used by the parser cache
4007  *
4008  * @return BagOStuff
4009  */
4010 function wfGetParserCacheStorage() {
4011         global $wgParserCacheType;
4012         return ObjectCache::getInstance( $wgParserCacheType );
4013 }
4014
4015 /**
4016  * Get the cache object used by the language converter
4017  *
4018  * @return BagOStuff
4019  */
4020 function wfGetLangConverterCacheStorage() {
4021         global $wgLanguageConverterCacheType;
4022         return ObjectCache::getInstance( $wgLanguageConverterCacheType );
4023 }
4024
4025 /**
4026  * Call hook functions defined in $wgHooks
4027  *
4028  * @param string $event event name
4029  * @param array $args parameters passed to hook functions
4030  * @return Boolean True if no handler aborted the hook
4031  */
4032 function wfRunHooks( $event, array $args = array() ) {
4033         return Hooks::run( $event, $args );
4034 }
4035
4036 /**
4037  * Wrapper around php's unpack.
4038  *
4039  * @param string $format The format string (See php's docs)
4040  * @param $data: A binary string of binary data
4041  * @param $length integer or false: The minimum length of $data. This is to
4042  *      prevent reading beyond the end of $data. false to disable the check.
4043  *
4044  * Also be careful when using this function to read unsigned 32 bit integer
4045  * because php might make it negative.
4046  *
4047  * @throws MWException if $data not long enough, or if unpack fails
4048  * @return array Associative array of the extracted data
4049  */
4050 function wfUnpack( $format, $data, $length = false ) {
4051         if ( $length !== false ) {
4052                 $realLen = strlen( $data );
4053                 if ( $realLen < $length ) {
4054                         throw new MWException( "Tried to use wfUnpack on a "
4055                                 . "string of length $realLen, but needed one "
4056                                 . "of at least length $length."
4057                         );
4058                 }
4059         }
4060
4061         wfSuppressWarnings();
4062         $result = unpack( $format, $data );
4063         wfRestoreWarnings();
4064
4065         if ( $result === false ) {
4066                 // If it cannot extract the packed data.
4067                 throw new MWException( "unpack could not unpack binary data" );
4068         }
4069         return $result;
4070 }
4071
4072 /**
4073  * Determine if an image exists on the 'bad image list'.
4074  *
4075  * The format of MediaWiki:Bad_image_list is as follows:
4076  *    * Only list items (lines starting with "*") are considered
4077  *    * The first link on a line must be a link to a bad image
4078  *    * Any subsequent links on the same line are considered to be exceptions,
4079  *      i.e. articles where the image may occur inline.
4080  *
4081  * @param string $name the image name to check
4082  * @param $contextTitle Title|bool the page on which the image occurs, if known
4083  * @param string $blacklist wikitext of a file blacklist
4084  * @return bool
4085  */
4086 function wfIsBadImage( $name, $contextTitle = false, $blacklist = null ) {
4087         static $badImageCache = null; // based on bad_image_list msg
4088         wfProfileIn( __METHOD__ );
4089
4090         # Handle redirects
4091         $redirectTitle = RepoGroup::singleton()->checkRedirect( Title::makeTitle( NS_FILE, $name ) );
4092         if ( $redirectTitle ) {
4093                 $name = $redirectTitle->getDBkey();
4094         }
4095
4096         # Run the extension hook
4097         $bad = false;
4098         if ( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
4099                 wfProfileOut( __METHOD__ );
4100                 return $bad;
4101         }
4102
4103         $cacheable = ( $blacklist === null );
4104         if ( $cacheable && $badImageCache !== null ) {
4105                 $badImages = $badImageCache;
4106         } else { // cache miss
4107                 if ( $blacklist === null ) {
4108                         $blacklist = wfMessage( 'bad_image_list' )->inContentLanguage()->plain(); // site list
4109                 }
4110                 # Build the list now
4111                 $badImages = array();
4112                 $lines = explode( "\n", $blacklist );
4113                 foreach ( $lines as $line ) {
4114                         # List items only
4115                         if ( substr( $line, 0, 1 ) !== '*' ) {
4116                                 continue;
4117                         }
4118
4119                         # Find all links
4120                         $m = array();
4121                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
4122                                 continue;
4123                         }
4124
4125                         $exceptions = array();
4126                         $imageDBkey = false;
4127                         foreach ( $m[1] as $i => $titleText ) {
4128                                 $title = Title::newFromText( $titleText );
4129                                 if ( !is_null( $title ) ) {
4130                                         if ( $i == 0 ) {
4131                                                 $imageDBkey = $title->getDBkey();
4132                                         } else {
4133                                                 $exceptions[$title->getPrefixedDBkey()] = true;
4134                                         }
4135                                 }
4136                         }
4137
4138                         if ( $imageDBkey !== false ) {
4139                                 $badImages[$imageDBkey] = $exceptions;
4140                         }
4141                 }
4142                 if ( $cacheable ) {
4143                         $badImageCache = $badImages;
4144                 }
4145         }
4146
4147         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
4148         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
4149         wfProfileOut( __METHOD__ );
4150         return $bad;
4151 }
4152
4153 /**
4154  * Determine whether the client at a given source IP is likely to be able to
4155  * access the wiki via HTTPS.
4156  *
4157  * @param string $ip The IPv4/6 address in the normal human-readable form
4158  * @return boolean
4159  */
4160 function wfCanIPUseHTTPS( $ip ) {
4161         $canDo = true;
4162         wfRunHooks( 'CanIPUseHTTPS', array( $ip, &$canDo ) );
4163         return !!$canDo;
4164 }