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