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 5.3.3 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( 'mb_substr' ) ) {
  39         /**
  40          * @codeCoverageIgnore
  41          * @see Fallback::mb_substr
  42          * @return string
  43          */
  44         function mb_substr( $str, $start, $count = 'end' ) {
  45                 return Fallback::mb_substr( $str, $start, $count );
  46         }
  47
  48         /**
  49          * @codeCoverageIgnore
  50          * @see Fallback::mb_substr_split_unicode
  51          * @return int
  52          */
  53         function mb_substr_split_unicode( $str, $splitPos ) {
  54                 return Fallback::mb_substr_split_unicode( $str, $splitPos );
  55         }
  56 }
  57
  58 if ( !function_exists( 'mb_strlen' ) ) {
  59         /**
  60          * @codeCoverageIgnore
  61          * @see Fallback::mb_strlen
  62          * @return int
  63          */
  64         function mb_strlen( $str, $enc = '' ) {
  65                 return Fallback::mb_strlen( $str, $enc );
  66         }
  67 }
  68
  69 if ( !function_exists( 'mb_strpos' ) ) {
  70         /**
  71          * @codeCoverageIgnore
  72          * @see Fallback::mb_strpos
  73          * @return int
  74          */
  75         function mb_strpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  76                 return Fallback::mb_strpos( $haystack, $needle, $offset, $encoding );
  77         }
  78 }
  79
  80 if ( !function_exists( 'mb_strrpos' ) ) {
  81         /**
  82          * @codeCoverageIgnore
  83          * @see Fallback::mb_strrpos
  84          * @return int
  85          */
  86         function mb_strrpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  87                 return Fallback::mb_strrpos( $haystack, $needle, $offset, $encoding );
  88         }
  89 }
  90
  91 // gzdecode function only exists in PHP >= 5.4.0
  92 // http://php.net/gzdecode
  93 if ( !function_exists( 'gzdecode' ) ) {
  94         /**
  95          * @codeCoverageIgnore
  96          * @param string $data
  97          * @return string
  98          */
  99         function gzdecode( $data ) {
 100                 return gzinflate( substr( $data, 10, -8 ) );
 101         }
 102 }
 103
 104 // hash_equals function only exists in PHP >= 5.6.0
 105 // http://php.net/hash_equals
 106 if ( !function_exists( 'hash_equals' ) ) {
 107         /**
 108          * Check whether a user-provided string is equal to a fixed-length secret string
 109          * without revealing bytes of the secret string through timing differences.
 110          *
 111          * The usual way to compare strings (PHP's === operator or the underlying memcmp()
 112          * function in C) is to compare corresponding bytes and stop at the first difference,
 113          * which would take longer for a partial match than for a complete mismatch. This
 114          * is not secure when one of the strings (e.g. an HMAC or token) must remain secret
 115          * and the other may come from an attacker. Statistical analysis of timing measurements
 116          * over many requests may allow the attacker to guess the string's bytes one at a time
 117          * (and check his guesses) even if the timing differences are extremely small.
 118          *
 119          * When making such a security-sensitive comparison, it is essential that the sequence
 120          * in which instructions are executed and memory locations are accessed not depend on
 121          * the secret string's value. HOWEVER, for simplicity, we do not attempt to minimize
 122          * the inevitable leakage of the string's length. That is generally known anyway as
 123          * a chararacteristic of the hash function used to compute the secret value.
 124          *
 125          * Longer explanation: http://www.emerose.com/timing-attacks-explained
 126          *
 127          * @codeCoverageIgnore
 128          * @param string $known_string Fixed-length secret string to compare against
 129          * @param string $user_string User-provided string
 130          * @return bool True if the strings are the same, false otherwise
 131          */
 132         function hash_equals( $known_string, $user_string ) {
 133                 // Strict type checking as in PHP's native implementation
 134                 if ( !is_string( $known_string ) ) {
 135                         trigger_error( 'hash_equals(): Expected known_string to be a string, ' .
 136                                 gettype( $known_string ) . ' given', E_USER_WARNING );
 137
 138                         return false;
 139                 }
 140
 141                 if ( !is_string( $user_string ) ) {
 142                         trigger_error( 'hash_equals(): Expected user_string to be a string, ' .
 143                                 gettype( $user_string ) . ' given', E_USER_WARNING );
 144
 145                         return false;
 146                 }
 147
 148                 $known_string_len = strlen( $known_string );
 149                 if ( $known_string_len !== strlen( $user_string ) ) {
 150                         return false;
 151                 }
 152
 153                 $result = 0;
 154                 for ( $i = 0; $i < $known_string_len; $i++ ) {
 155                         $result |= ord( $known_string[$i] ) ^ ord( $user_string[$i] );
 156                 }
 157
 158                 return ( $result === 0 );
 159         }
 160 }
 161 /// @endcond
 162
 163 /**
 164  * Like array_diff( $a, $b ) except that it works with two-dimensional arrays.
 165  * @param array $a
 166  * @param array $b
 167  * @return array
 168  */
 169 function wfArrayDiff2( $a, $b ) {
 170         return array_udiff( $a, $b, 'wfArrayDiff2_cmp' );
 171 }
 172
 173 /**
 174  * @param array|string $a
 175  * @param array|string $b
 176  * @return int
 177  */
 178 function wfArrayDiff2_cmp( $a, $b ) {
 179         if ( is_string( $a ) && is_string( $b ) ) {
 180                 return strcmp( $a, $b );
 181         } elseif ( count( $a ) !== count( $b ) ) {
 182                 return count( $a ) < count( $b ) ? -1 : 1;
 183         } else {
 184                 reset( $a );
 185                 reset( $b );
 186                 while ( ( list( , $valueA ) = each( $a ) ) && ( list( , $valueB ) = each( $b ) ) ) {
 187                         $cmp = strcmp( $valueA, $valueB );
 188                         if ( $cmp !== 0 ) {
 189                                 return $cmp;
 190                         }
 191                 }
 192                 return 0;
 193         }
 194 }
 195
 196 /**
 197  * Appends to second array if $value differs from that in $default
 198  *
 199  * @param string|int $key
 200  * @param mixed $value
 201  * @param mixed $default
 202  * @param array $changed Array to alter
 203  * @throws MWException
 204  */
 205 function wfAppendToArrayIfNotDefault( $key, $value, $default, &$changed ) {
 206         if ( is_null( $changed ) ) {
 207                 throw new MWException( 'GlobalFunctions::wfAppendToArrayIfNotDefault got null' );
 208         }
 209         if ( $default[$key] !== $value ) {
 210                 $changed[$key] = $value;
 211         }
 212 }
 213
 214 /**
 215  * Merge arrays in the style of getUserPermissionsErrors, with duplicate removal
 216  * e.g.
 217  *      wfMergeErrorArrays(
 218  *              array( array( 'x' ) ),
 219  *              array( array( 'x', '2' ) ),
 220  *              array( array( 'x' ) ),
 221  *              array( array( 'y' ) )
 222  *      );
 223  * returns:
 224  *              array(
 225  *              array( 'x', '2' ),
 226  *              array( 'x' ),
 227  *              array( 'y' )
 228  *      )
 229  *
 230  * @param array $array1,...
 231  * @return array
 232  */
 233 function wfMergeErrorArrays( /*...*/ ) {
 234         $args = func_get_args();
 235         $out = array();
 236         foreach ( $args as $errors ) {
 237                 foreach ( $errors as $params ) {
 238                         # @todo FIXME: Sometimes get nested arrays for $params,
 239                         # which leads to E_NOTICEs
 240                         $spec = implode( "\t", $params );
 241                         $out[$spec] = $params;
 242                 }
 243         }
 244         return array_values( $out );
 245 }
 246
 247 /**
 248  * Insert array into another array after the specified *KEY*
 249  *
 250  * @param array $array The array.
 251  * @param array $insert The array to insert.
 252  * @param mixed $after The key to insert after
 253  * @return array
 254  */
 255 function wfArrayInsertAfter( array $array, array $insert, $after ) {
 256         // Find the offset of the element to insert after.
 257         $keys = array_keys( $array );
 258         $offsetByKey = array_flip( $keys );
 259
 260         $offset = $offsetByKey[$after];
 261
 262         // Insert at the specified offset
 263         $before = array_slice( $array, 0, $offset + 1, true );
 264         $after = array_slice( $array, $offset + 1, count( $array ) - $offset, true );
 265
 266         $output = $before + $insert + $after;
 267
 268         return $output;
 269 }
 270
 271 /**
 272  * Recursively converts the parameter (an object) to an array with the same data
 273  *
 274  * @param object|array $objOrArray
 275  * @param bool $recursive
 276  * @return array
 277  */
 278 function wfObjectToArray( $objOrArray, $recursive = true ) {
 279         $array = array();
 280         if ( is_object( $objOrArray ) ) {
 281                 $objOrArray = get_object_vars( $objOrArray );
 282         }
 283         foreach ( $objOrArray as $key => $value ) {
 284                 if ( $recursive && ( is_object( $value ) || is_array( $value ) ) ) {
 285                         $value = wfObjectToArray( $value );
 286                 }
 287
 288                 $array[$key] = $value;
 289         }
 290
 291         return $array;
 292 }
 293
 294 /**
 295  * Get a random decimal value between 0 and 1, in a way
 296  * not likely to give duplicate values for any realistic
 297  * number of articles.
 298  *
 299  * @return string
 300  */
 301 function wfRandom() {
 302         # The maximum random value is "only" 2^31-1, so get two random
 303         # values to reduce the chance of dupes
 304         $max = mt_getrandmax() + 1;
 305         $rand = number_format( ( mt_rand() * $max + mt_rand() ) / $max / $max, 12, '.', '' );
 306
 307         return $rand;
 308 }
 309
 310 /**
 311  * Get a random string containing a number of pseudo-random hex
 312  * characters.
 313  * @note This is not secure, if you are trying to generate some sort
 314  *       of token please use MWCryptRand instead.
 315  *
 316  * @param int $length The length of the string to generate
 317  * @return string
 318  * @since 1.20
 319  */
 320 function wfRandomString( $length = 32 ) {
 321         $str = '';
 322         for ( $n = 0; $n < $length; $n += 7 ) {
 323                 $str .= sprintf( '%07x', mt_rand() & 0xfffffff );
 324         }
 325         return substr( $str, 0, $length );
 326 }
 327
 328 /**
 329  * We want some things to be included as literal characters in our title URLs
 330  * for prettiness, which urlencode encodes by default.  According to RFC 1738,
 331  * all of the following should be safe:
 332  *
 333  * ;:@&=$-_.+!*'(),
 334  *
 335  * But + is not safe because it's used to indicate a space; &= are only safe in
 336  * paths and not in queries (and we don't distinguish here); ' seems kind of
 337  * scary; and urlencode() doesn't touch -_. to begin with.  Plus, although /
 338  * is reserved, we don't care.  So the list we unescape is:
 339  *
 340  * ;:@$!*(),/
 341  *
 342  * However, IIS7 redirects fail when the url contains a colon (Bug 22709),
 343  * so no fancy : for IIS7.
 344  *
 345  * %2F in the page titles seems to fatally break for some reason.
 346  *
 347  * @param string $s
 348  * @return string
 349  */
 350 function wfUrlencode( $s ) {
 351         static $needle;
 352
 353         if ( is_null( $s ) ) {
 354                 $needle = null;
 355                 return '';
 356         }
 357
 358         if ( is_null( $needle ) ) {
 359                 $needle = array( '%3B', '%40', '%24', '%21', '%2A', '%28', '%29', '%2C', '%2F' );
 360                 if ( !isset( $_SERVER['SERVER_SOFTWARE'] ) ||
 361                         ( strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/7' ) === false )
 362                 ) {
 363                         $needle[] = '%3A';
 364                 }
 365         }
 366
 367         $s = urlencode( $s );
 368         $s = str_ireplace(
 369                 $needle,
 370                 array( ';', '@', '$', '!', '*', '(', ')', ',', '/', ':' ),
 371                 $s
 372         );
 373
 374         return $s;
 375 }
 376
 377 /**
 378  * This function takes two arrays as input, and returns a CGI-style string, e.g.
 379  * "days=7&limit=100". Options in the first array override options in the second.
 380  * Options set to null or false will not be output.
 381  *
 382  * @param array $array1 ( String|Array )
 383  * @param array $array2 ( String|Array )
 384  * @param string $prefix
 385  * @return string
 386  */
 387 function wfArrayToCgi( $array1, $array2 = null, $prefix = '' ) {
 388         if ( !is_null( $array2 ) ) {
 389                 $array1 = $array1 + $array2;
 390         }
 391
 392         $cgi = '';
 393         foreach ( $array1 as $key => $value ) {
 394                 if ( !is_null( $value ) && $value !== false ) {
 395                         if ( $cgi != '' ) {
 396                                 $cgi .= '&';
 397                         }
 398                         if ( $prefix !== '' ) {
 399                                 $key = $prefix . "[$key]";
 400                         }
 401                         if ( is_array( $value ) ) {
 402                                 $firstTime = true;
 403                                 foreach ( $value as $k => $v ) {
 404                                         $cgi .= $firstTime ? '' : '&';
 405                                         if ( is_array( $v ) ) {
 406                                                 $cgi .= wfArrayToCgi( $v, null, $key . "[$k]" );
 407                                         } else {
 408                                                 $cgi .= urlencode( $key . "[$k]" ) . '=' . urlencode( $v );
 409                                         }
 410                                         $firstTime = false;
 411                                 }
 412                         } else {
 413                                 if ( is_object( $value ) ) {
 414                                         $value = $value->__toString();
 415                                 }
 416                                 $cgi .= urlencode( $key ) . '=' . urlencode( $value );
 417                         }
 418                 }
 419         }
 420         return $cgi;
 421 }
 422
 423 /**
 424  * This is the logical opposite of wfArrayToCgi(): it accepts a query string as
 425  * its argument and returns the same string in array form.  This allows compatibility
 426  * with legacy functions that accept raw query strings instead of nice
 427  * arrays.  Of course, keys and values are urldecode()d.
 428  *
 429  * @param string $query Query string
 430  * @return string[] Array version of input
 431  */
 432 function wfCgiToArray( $query ) {
 433         if ( isset( $query[0] ) && $query[0] == '?' ) {
 434                 $query = substr( $query, 1 );
 435         }
 436         $bits = explode( '&', $query );
 437         $ret = array();
 438         foreach ( $bits as $bit ) {
 439                 if ( $bit === '' ) {
 440                         continue;
 441                 }
 442                 if ( strpos( $bit, '=' ) === false ) {
 443                         // Pieces like &qwerty become 'qwerty' => '' (at least this is what php does)
 444                         $key = $bit;
 445                         $value = '';
 446                 } else {
 447                         list( $key, $value ) = explode( '=', $bit );
 448                 }
 449                 $key = urldecode( $key );
 450                 $value = urldecode( $value );
 451                 if ( strpos( $key, '[' ) !== false ) {
 452                         $keys = array_reverse( explode( '[', $key ) );
 453                         $key = array_pop( $keys );
 454                         $temp = $value;
 455                         foreach ( $keys as $k ) {
 456                                 $k = substr( $k, 0, -1 );
 457                                 $temp = array( $k => $temp );
 458                         }
 459                         if ( isset( $ret[$key] ) ) {
 460                                 $ret[$key] = array_merge( $ret[$key], $temp );
 461                         } else {
 462                                 $ret[$key] = $temp;
 463                         }
 464                 } else {
 465                         $ret[$key] = $value;
 466                 }
 467         }
 468         return $ret;
 469 }
 470
 471 /**
 472  * Append a query string to an existing URL, which may or may not already
 473  * have query string parameters already. If so, they will be combined.
 474  *
 475  * @param string $url
 476  * @param string|string[] $query String or associative array
 477  * @return string
 478  */
 479 function wfAppendQuery( $url, $query ) {
 480         if ( is_array( $query ) ) {
 481                 $query = wfArrayToCgi( $query );
 482         }
 483         if ( $query != '' ) {
 484                 if ( false === strpos( $url, '?' ) ) {
 485                         $url .= '?';
 486                 } else {
 487                         $url .= '&';
 488                 }
 489                 $url .= $query;
 490         }
 491         return $url;
 492 }
 493
 494 /**
 495  * Expand a potentially local URL to a fully-qualified URL. Assumes $wgServer
 496  * is correct.
 497  *
 498  * The meaning of the PROTO_* constants is as follows:
 499  * PROTO_HTTP: Output a URL starting with http://
 500  * PROTO_HTTPS: Output a URL starting with https://
 501  * PROTO_RELATIVE: Output a URL starting with // (protocol-relative URL)
 502  * PROTO_CURRENT: Output a URL starting with either http:// or https:// , depending
 503  *    on which protocol was used for the current incoming request
 504  * PROTO_CANONICAL: For URLs without a domain, like /w/index.php , use $wgCanonicalServer.
 505  *    For protocol-relative URLs, use the protocol of $wgCanonicalServer
 506  * PROTO_INTERNAL: Like PROTO_CANONICAL, but uses $wgInternalServer instead of $wgCanonicalServer
 507  *
 508  * @todo this won't work with current-path-relative URLs
 509  * like "subdir/foo.html", etc.
 510  *
 511  * @param string $url Either fully-qualified or a local path + query
 512  * @param string $defaultProto One of the PROTO_* constants. Determines the
 513  *    protocol to use if $url or $wgServer is protocol-relative
 514  * @return string Fully-qualified URL, current-path-relative URL or false if
 515  *    no valid URL can be constructed
 516  */
 517 function wfExpandUrl( $url, $defaultProto = PROTO_CURRENT ) {
 518         global $wgServer, $wgCanonicalServer, $wgInternalServer, $wgRequest,
 519                 $wgHttpsPort;
 520         if ( $defaultProto === PROTO_CANONICAL ) {
 521                 $serverUrl = $wgCanonicalServer;
 522         } elseif ( $defaultProto === PROTO_INTERNAL && $wgInternalServer !== false ) {
 523                 // Make $wgInternalServer fall back to $wgServer if not set
 524                 $serverUrl = $wgInternalServer;
 525         } else {
 526                 $serverUrl = $wgServer;
 527                 if ( $defaultProto === PROTO_CURRENT ) {
 528                         $defaultProto = $wgRequest->getProtocol() . '://';
 529                 }
 530         }
 531
 532         // Analyze $serverUrl to obtain its protocol
 533         $bits = wfParseUrl( $serverUrl );
 534         $serverHasProto = $bits && $bits['scheme'] != '';
 535
 536         if ( $defaultProto === PROTO_CANONICAL || $defaultProto === PROTO_INTERNAL ) {
 537                 if ( $serverHasProto ) {
 538                         $defaultProto = $bits['scheme'] . '://';
 539                 } else {
 540                         // $wgCanonicalServer or $wgInternalServer doesn't have a protocol.
 541                         // This really isn't supposed to happen. Fall back to HTTP in this
 542                         // ridiculous case.
 543                         $defaultProto = PROTO_HTTP;
 544                 }
 545         }
 546
 547         $defaultProtoWithoutSlashes = substr( $defaultProto, 0, -2 );
 548
 549         if ( substr( $url, 0, 2 ) == '//' ) {
 550                 $url = $defaultProtoWithoutSlashes . $url;
 551         } elseif ( substr( $url, 0, 1 ) == '/' ) {
 552                 // If $serverUrl is protocol-relative, prepend $defaultProtoWithoutSlashes,
 553                 // otherwise leave it alone.
 554                 $url = ( $serverHasProto ? '' : $defaultProtoWithoutSlashes ) . $serverUrl . $url;
 555         }
 556
 557         $bits = wfParseUrl( $url );
 558
 559         // ensure proper port for HTTPS arrives in URL
 560         // https://bugzilla.wikimedia.org/show_bug.cgi?id=65184
 561         if ( $defaultProto === PROTO_HTTPS && $wgHttpsPort != 443 ) {
 562                 $bits['port'] = $wgHttpsPort;
 563         }
 564
 565         if ( $bits && isset( $bits['path'] ) ) {
 566                 $bits['path'] = wfRemoveDotSegments( $bits['path'] );
 567                 return wfAssembleUrl( $bits );
 568         } elseif ( $bits ) {
 569                 # No path to expand
 570                 return $url;
 571         } elseif ( substr( $url, 0, 1 ) != '/' ) {
 572                 # URL is a relative path
 573                 return wfRemoveDotSegments( $url );
 574         }
 575
 576         # Expanded URL is not valid.
 577         return false;
 578 }
 579
 580 /**
 581  * This function will reassemble a URL parsed with wfParseURL.  This is useful
 582  * if you need to edit part of a URL and put it back together.
 583  *
 584  * This is the basic structure used (brackets contain keys for $urlParts):
 585  * [scheme][delimiter][user]:[pass]@[host]:[port][path]?[query]#[fragment]
 586  *
 587  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 588  *
 589  * @since 1.19
 590  * @param array $urlParts URL parts, as output from wfParseUrl
 591  * @return string URL assembled from its component parts
 592  */
 593 function wfAssembleUrl( $urlParts ) {
 594         $result = '';
 595
 596         if ( isset( $urlParts['delimiter'] ) ) {
 597                 if ( isset( $urlParts['scheme'] ) ) {
 598                         $result .= $urlParts['scheme'];
 599                 }
 600
 601                 $result .= $urlParts['delimiter'];
 602         }
 603
 604         if ( isset( $urlParts['host'] ) ) {
 605                 if ( isset( $urlParts['user'] ) ) {
 606                         $result .= $urlParts['user'];
 607                         if ( isset( $urlParts['pass'] ) ) {
 608                                 $result .= ':' . $urlParts['pass'];
 609                         }
 610                         $result .= '@';
 611                 }
 612
 613                 $result .= $urlParts['host'];
 614
 615                 if ( isset( $urlParts['port'] ) ) {
 616                         $result .= ':' . $urlParts['port'];
 617                 }
 618         }
 619
 620         if ( isset( $urlParts['path'] ) ) {
 621                 $result .= $urlParts['path'];
 622         }
 623
 624         if ( isset( $urlParts['query'] ) ) {
 625                 $result .= '?' . $urlParts['query'];
 626         }
 627
 628         if ( isset( $urlParts['fragment'] ) ) {
 629                 $result .= '#' . $urlParts['fragment'];
 630         }
 631
 632         return $result;
 633 }
 634
 635 /**
 636  * Remove all dot-segments in the provided URL path.  For example,
 637  * '/a/./b/../c/' becomes '/a/c/'.  For details on the algorithm, please see
 638  * RFC3986 section 5.2.4.
 639  *
 640  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 641  *
 642  * @param string $urlPath URL path, potentially containing dot-segments
 643  * @return string URL path with all dot-segments removed
 644  */
 645 function wfRemoveDotSegments( $urlPath ) {
 646         $output = '';
 647         $inputOffset = 0;
 648         $inputLength = strlen( $urlPath );
 649
 650         while ( $inputOffset < $inputLength ) {
 651                 $prefixLengthOne = substr( $urlPath, $inputOffset, 1 );
 652                 $prefixLengthTwo = substr( $urlPath, $inputOffset, 2 );
 653                 $prefixLengthThree = substr( $urlPath, $inputOffset, 3 );
 654                 $prefixLengthFour = substr( $urlPath, $inputOffset, 4 );
 655                 $trimOutput = false;
 656
 657                 if ( $prefixLengthTwo == './' ) {
 658                         # Step A, remove leading "./"
 659                         $inputOffset += 2;
 660                 } elseif ( $prefixLengthThree == '../' ) {
 661                         # Step A, remove leading "../"
 662                         $inputOffset += 3;
 663                 } elseif ( ( $prefixLengthTwo == '/.' ) && ( $inputOffset + 2 == $inputLength ) ) {
 664                         # Step B, replace leading "/.$" with "/"
 665                         $inputOffset += 1;
 666                         $urlPath[$inputOffset] = '/';
 667                 } elseif ( $prefixLengthThree == '/./' ) {
 668                         # Step B, replace leading "/./" with "/"
 669                         $inputOffset += 2;
 670                 } elseif ( $prefixLengthThree == '/..' && ( $inputOffset + 3 == $inputLength ) ) {
 671                         # Step C, replace leading "/..$" with "/" and
 672                         # remove last path component in output
 673                         $inputOffset += 2;
 674                         $urlPath[$inputOffset] = '/';
 675                         $trimOutput = true;
 676                 } elseif ( $prefixLengthFour == '/../' ) {
 677                         # Step C, replace leading "/../" with "/" and
 678                         # remove last path component in output
 679                         $inputOffset += 3;
 680                         $trimOutput = true;
 681                 } elseif ( ( $prefixLengthOne == '.' ) && ( $inputOffset + 1 == $inputLength ) ) {
 682                         # Step D, remove "^.$"
 683                         $inputOffset += 1;
 684                 } elseif ( ( $prefixLengthTwo == '..' ) && ( $inputOffset + 2 == $inputLength ) ) {
 685                         # Step D, remove "^..$"
 686                         $inputOffset += 2;
 687                 } else {
 688                         # Step E, move leading path segment to output
 689                         if ( $prefixLengthOne == '/' ) {
 690                                 $slashPos = strpos( $urlPath, '/', $inputOffset + 1 );
 691                         } else {
 692                                 $slashPos = strpos( $urlPath, '/', $inputOffset );
 693                         }
 694                         if ( $slashPos === false ) {
 695                                 $output .= substr( $urlPath, $inputOffset );
 696                                 $inputOffset = $inputLength;
 697                         } else {
 698                                 $output .= substr( $urlPath, $inputOffset, $slashPos - $inputOffset );
 699                                 $inputOffset += $slashPos - $inputOffset;
 700                         }
 701                 }
 702
 703                 if ( $trimOutput ) {
 704                         $slashPos = strrpos( $output, '/' );
 705                         if ( $slashPos === false ) {
 706                                 $output = '';
 707                         } else {
 708                                 $output = substr( $output, 0, $slashPos );
 709                         }
 710                 }
 711         }
 712
 713         return $output;
 714 }
 715
 716 /**
 717  * Returns a regular expression of url protocols
 718  *
 719  * @param bool $includeProtocolRelative If false, remove '//' from the returned protocol list.
 720  *        DO NOT USE this directly, use wfUrlProtocolsWithoutProtRel() instead
 721  * @return string
 722  */
 723 function wfUrlProtocols( $includeProtocolRelative = true ) {
 724         global $wgUrlProtocols;
 725
 726         // Cache return values separately based on $includeProtocolRelative
 727         static $withProtRel = null, $withoutProtRel = null;
 728         $cachedValue = $includeProtocolRelative ? $withProtRel : $withoutProtRel;
 729         if ( !is_null( $cachedValue ) ) {
 730                 return $cachedValue;
 731         }
 732
 733         // Support old-style $wgUrlProtocols strings, for backwards compatibility
 734         // with LocalSettings files from 1.5
 735         if ( is_array( $wgUrlProtocols ) ) {
 736                 $protocols = array();
 737                 foreach ( $wgUrlProtocols as $protocol ) {
 738                         // Filter out '//' if !$includeProtocolRelative
 739                         if ( $includeProtocolRelative || $protocol !== '//' ) {
 740                                 $protocols[] = preg_quote( $protocol, '/' );
 741                         }
 742                 }
 743
 744                 $retval = implode( '|', $protocols );
 745         } else {
 746                 // Ignore $includeProtocolRelative in this case
 747                 // This case exists for pre-1.6 compatibility, and we can safely assume
 748                 // that '//' won't appear in a pre-1.6 config because protocol-relative
 749                 // URLs weren't supported until 1.18
 750                 $retval = $wgUrlProtocols;
 751         }
 752
 753         // Cache return value
 754         if ( $includeProtocolRelative ) {
 755                 $withProtRel = $retval;
 756         } else {
 757                 $withoutProtRel = $retval;
 758         }
 759         return $retval;
 760 }
 761
 762 /**
 763  * Like wfUrlProtocols(), but excludes '//' from the protocol list. Use this if
 764  * you need a regex that matches all URL protocols but does not match protocol-
 765  * relative URLs
 766  * @return string
 767  */
 768 function wfUrlProtocolsWithoutProtRel() {
 769         return wfUrlProtocols( false );
 770 }
 771
 772 /**
 773  * parse_url() work-alike, but non-broken.  Differences:
 774  *
 775  * 1) Does not raise warnings on bad URLs (just returns false).
 776  * 2) Handles protocols that don't use :// (e.g., mailto: and news:, as well as
 777  *    protocol-relative URLs) correctly.
 778  * 3) Adds a "delimiter" element to the array, either '://', ':' or '//' (see (2)).
 779  *
 780  * @param string $url A URL to parse
 781  * @return string[] Bits of the URL in an associative array, per PHP docs
 782  */
 783 function wfParseUrl( $url ) {
 784         global $wgUrlProtocols; // Allow all protocols defined in DefaultSettings/LocalSettings.php
 785
 786         // Protocol-relative URLs are handled really badly by parse_url(). It's so
 787         // bad that the easiest way to handle them is to just prepend 'http:' and
 788         // strip the protocol out later.
 789         $wasRelative = substr( $url, 0, 2 ) == '//';
 790         if ( $wasRelative ) {
 791                 $url = "http:$url";
 792         }
 793         wfSuppressWarnings();
 794         $bits = parse_url( $url );
 795         wfRestoreWarnings();
 796         // parse_url() returns an array without scheme for some invalid URLs, e.g.
 797         // parse_url("%0Ahttp://example.com") == array( 'host' => '%0Ahttp', 'path' => 'example.com' )
 798         if ( !$bits || !isset( $bits['scheme'] ) ) {
 799                 return false;
 800         }
 801
 802         // parse_url() incorrectly handles schemes case-sensitively. Convert it to lowercase.
 803         $bits['scheme'] = strtolower( $bits['scheme'] );
 804
 805         // most of the protocols are followed by ://, but mailto: and sometimes news: not, check for it
 806         if ( in_array( $bits['scheme'] . '://', $wgUrlProtocols ) ) {
 807                 $bits['delimiter'] = '://';
 808         } elseif ( in_array( $bits['scheme'] . ':', $wgUrlProtocols ) ) {
 809                 $bits['delimiter'] = ':';
 810                 // parse_url detects for news: and mailto: the host part of an url as path
 811                 // We have to correct this wrong detection
 812                 if ( isset( $bits['path'] ) ) {
 813                         $bits['host'] = $bits['path'];
 814                         $bits['path'] = '';
 815                 }
 816         } else {
 817                 return false;
 818         }
 819
 820         /* Provide an empty host for eg. file:/// urls (see bug 28627) */
 821         if ( !isset( $bits['host'] ) ) {
 822                 $bits['host'] = '';
 823
 824                 // bug 45069
 825                 if ( isset( $bits['path'] ) ) {
 826                         /* parse_url loses the third / for file:///c:/ urls (but not on variants) */
 827                         if ( substr( $bits['path'], 0, 1 ) !== '/' ) {
 828                                 $bits['path'] = '/' . $bits['path'];
 829                         }
 830                 } else {
 831                         $bits['path'] = '';
 832                 }
 833         }
 834
 835         // If the URL was protocol-relative, fix scheme and delimiter
 836         if ( $wasRelative ) {
 837                 $bits['scheme'] = '';
 838                 $bits['delimiter'] = '//';
 839         }
 840         return $bits;
 841 }
 842
 843 /**
 844  * Take a URL, make sure it's expanded to fully qualified, and replace any
 845  * encoded non-ASCII Unicode characters with their UTF-8 original forms
 846  * for more compact display and legibility for local audiences.
 847  *
 848  * @todo handle punycode domains too
 849  *
 850  * @param string $url
 851  * @return string
 852  */
 853 function wfExpandIRI( $url ) {
 854         return preg_replace_callback(
 855                 '/((?:%[89A-F][0-9A-F])+)/i',
 856                 'wfExpandIRI_callback',
 857                 wfExpandUrl( $url )
 858         );
 859 }
 860
 861 /**
 862  * Private callback for wfExpandIRI
 863  * @param array $matches
 864  * @return string
 865  */
 866 function wfExpandIRI_callback( $matches ) {
 867         return urldecode( $matches[1] );
 868 }
 869
 870 /**
 871  * Make URL indexes, appropriate for the el_index field of externallinks.
 872  *
 873  * @param string $url
 874  * @return array
 875  */
 876 function wfMakeUrlIndexes( $url ) {
 877         $bits = wfParseUrl( $url );
 878
 879         // Reverse the labels in the hostname, convert to lower case
 880         // For emails reverse domainpart only
 881         if ( $bits['scheme'] == 'mailto' ) {
 882                 $mailparts = explode( '@', $bits['host'], 2 );
 883                 if ( count( $mailparts ) === 2 ) {
 884                         $domainpart = strtolower( implode( '.', array_reverse( explode( '.', $mailparts[1] ) ) ) );
 885                 } else {
 886                         // No domain specified, don't mangle it
 887                         $domainpart = '';
 888                 }
 889                 $reversedHost = $domainpart . '@' . $mailparts[0];
 890         } else {
 891                 $reversedHost = strtolower( implode( '.', array_reverse( explode( '.', $bits['host'] ) ) ) );
 892         }
 893         // Add an extra dot to the end
 894         // Why? Is it in wrong place in mailto links?
 895         if ( substr( $reversedHost, -1, 1 ) !== '.' ) {
 896                 $reversedHost .= '.';
 897         }
 898         // Reconstruct the pseudo-URL
 899         $prot = $bits['scheme'];
 900         $index = $prot . $bits['delimiter'] . $reversedHost;
 901         // Leave out user and password. Add the port, path, query and fragment
 902         if ( isset( $bits['port'] ) ) {
 903                 $index .= ':' . $bits['port'];
 904         }
 905         if ( isset( $bits['path'] ) ) {
 906                 $index .= $bits['path'];
 907         } else {
 908                 $index .= '/';
 909         }
 910         if ( isset( $bits['query'] ) ) {
 911                 $index .= '?' . $bits['query'];
 912         }
 913         if ( isset( $bits['fragment'] ) ) {
 914                 $index .= '#' . $bits['fragment'];
 915         }
 916
 917         if ( $prot == '' ) {
 918                 return array( "http:$index", "https:$index" );
 919         } else {
 920                 return array( $index );
 921         }
 922 }
 923
 924 /**
 925  * Check whether a given URL has a domain that occurs in a given set of domains
 926  * @param string $url URL
 927  * @param array $domains Array of domains (strings)
 928  * @return bool True if the host part of $url ends in one of the strings in $domains
 929  */
 930 function wfMatchesDomainList( $url, $domains ) {
 931         $bits = wfParseUrl( $url );
 932         if ( is_array( $bits ) && isset( $bits['host'] ) ) {
 933                 $host = '.' . $bits['host'];
 934                 foreach ( (array)$domains as $domain ) {
 935                         $domain = '.' . $domain;
 936                         if ( substr( $host, -strlen( $domain ) ) === $domain ) {
 937                                 return true;
 938                         }
 939                 }
 940         }
 941         return false;
 942 }
 943
 944 /**
 945  * Sends a line to the debug log if enabled or, optionally, to a comment in output.
 946  * In normal operation this is a NOP.
 947  *
 948  * Controlling globals:
 949  * $wgDebugLogFile - points to the log file
 950  * $wgDebugRawPage - if false, 'action=raw' hits will not result in debug output.
 951  * $wgDebugComments - if on, some debug items may appear in comments in the HTML output.
 952  *
 953  * @param string $text
 954  * @param string|bool $dest Destination of the message:
 955  *     - 'all': both to the log and HTML (debug toolbar or HTML comments)
 956  *     - 'log': only to the log and not in HTML
 957  *   For backward compatibility, it can also take a boolean:
 958  *     - true: same as 'all'
 959  *     - false: same as 'log'
 960  */
 961 function wfDebug( $text, $dest = 'all' ) {
 962         global $wgDebugRawPage, $wgDebugLogPrefix;
 963
 964         if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
 965                 return;
 966         }
 967
 968         // Turn $dest into a string if it's a boolean (for b/c)
 969         if ( $dest === true ) {
 970                 $dest = 'all';
 971         } elseif ( $dest === false ) {
 972                 $dest = 'log';
 973         }
 974
 975         $timer = wfDebugTimer();
 976         if ( $timer !== '' ) {
 977                 // Prepend elapsed request time and real memory usage to each line
 978                 $text = preg_replace( '/[^\n]/', $timer . '\0', $text, 1 );
 979         }
 980
 981         if ( $dest === 'all' ) {
 982                 MWDebug::debugMsg( $text );
 983         }
 984
 985         $ctx = array();
 986         if ( $wgDebugLogPrefix !== '' ) {
 987                 $ctx['prefix'] = $wgDebugLogPrefix;
 988         }
 989
 990         $logger = MWLogger::getInstance( 'wfDebug' );
 991         $logger->debug( rtrim( $text, "\n" ), $ctx );
 992 }
 993
 994 /**
 995  * Returns true if debug logging should be suppressed if $wgDebugRawPage = false
 996  * @return bool
 997  */
 998 function wfIsDebugRawPage() {
 999         static $cache;
1000         if ( $cache !== null ) {
1001                 return $cache;
1002         }
1003         # Check for raw action using $_GET not $wgRequest, since the latter might not be initialised yet
1004         if ( ( isset( $_GET['action'] ) && $_GET['action'] == 'raw' )
1005                 || (
1006                         isset( $_SERVER['SCRIPT_NAME'] )
1007                         && substr( $_SERVER['SCRIPT_NAME'], -8 ) == 'load.php'
1008                 )
1009         ) {
1010                 $cache = true;
1011         } else {
1012                 $cache = false;
1013         }
1014         return $cache;
1015 }
1016
1017 /**
1018  * Get microsecond timestamps for debug logs
1019  *
1020  * @return string
1021  */
1022 function wfDebugTimer() {
1023         global $wgDebugTimestamps, $wgRequestTime;
1024
1025         if ( !$wgDebugTimestamps ) {
1026                 return '';
1027         }
1028
1029         $prefix = sprintf( "%6.4f", microtime( true ) - $wgRequestTime );
1030         $mem = sprintf( "%5.1fM", ( memory_get_usage( true ) / ( 1024 * 1024 ) ) );
1031         return "$prefix $mem  ";
1032 }
1033
1034 /**
1035  * Send a line giving PHP memory usage.
1036  *
1037  * @param bool $exact Print exact byte values instead of kibibytes (default: false)
1038  */
1039 function wfDebugMem( $exact = false ) {
1040         $mem = memory_get_usage();
1041         if ( !$exact ) {
1042                 $mem = floor( $mem / 1024 ) . ' KiB';
1043         } else {
1044                 $mem .= ' B';
1045         }
1046         wfDebug( "Memory usage: $mem\n" );
1047 }
1048
1049 /**
1050  * Send a line to a supplementary debug log file, if configured, or main debug log if not.
1051  * To configure a supplementary log file, set $wgDebugLogGroups[$logGroup] to a string
1052  * filename or an associative array mapping 'destination' to the desired filename. The
1053  * associative array may also contain a 'sample' key with an integer value, specifying
1054  * a sampling factor.
1055  *
1056  * @since 1.23 support for sampling log messages via $wgDebugLogGroups.
1057  *
1058  * @param string $logGroup
1059  * @param string $text
1060  * @param string|bool $dest Destination of the message:
1061  *     - 'all': both to the log and HTML (debug toolbar or HTML comments)
1062  *     - 'log': only to the log and not in HTML
1063  *     - 'private': only to the specifc log if set in $wgDebugLogGroups and
1064  *       discarded otherwise
1065  *   For backward compatibility, it can also take a boolean:
1066  *     - true: same as 'all'
1067  *     - false: same as 'private'
1068  */
1069 function wfDebugLog( $logGroup, $text, $dest = 'all' ) {
1070         // Turn $dest into a string if it's a boolean (for b/c)
1071         if ( $dest === true ) {
1072                 $dest = 'all';
1073         } elseif ( $dest === false ) {
1074                 $dest = 'private';
1075         }
1076
1077         $text = trim( $text );
1078
1079         if ( $dest === 'all' ) {
1080                 MWDebug::debugMsg( "[{$logGroup}] {$text}\n" );
1081         }
1082
1083         $logger = MWLogger::getInstance( $logGroup );
1084         $logger->debug( $text, array(
1085                 'private' => ( $dest === 'private' ),
1086         ) );
1087 }
1088
1089 /**
1090  * Log for database errors
1091  *
1092  * @param string $text Database error message.
1093  */
1094 function wfLogDBError( $text ) {
1095         $logger = MWLogger::getInstance( 'wfLogDBError' );
1096         $logger->error( trim( $text ) );
1097 }
1098
1099 /**
1100  * Throws a warning that $function is deprecated
1101  *
1102  * @param string $function
1103  * @param string|bool $version Version of MediaWiki that the function
1104  *    was deprecated in (Added in 1.19).
1105  * @param string|bool $component Added in 1.19.
1106  * @param int $callerOffset How far up the call stack is the original
1107  *    caller. 2 = function that called the function that called
1108  *    wfDeprecated (Added in 1.20)
1109  *
1110  * @return null
1111  */
1112 function wfDeprecated( $function, $version = false, $component = false, $callerOffset = 2 ) {
1113         MWDebug::deprecated( $function, $version, $component, $callerOffset + 1 );
1114 }
1115
1116 /**
1117  * Send a warning either to the debug log or in a PHP error depending on
1118  * $wgDevelopmentWarnings. To log warnings in production, use wfLogWarning() instead.
1119  *
1120  * @param string $msg Message to send
1121  * @param int $callerOffset Number of items to go back in the backtrace to
1122  *        find the correct caller (1 = function calling wfWarn, ...)
1123  * @param int $level PHP error level; defaults to E_USER_NOTICE;
1124  *        only used when $wgDevelopmentWarnings is true
1125  */
1126 function wfWarn( $msg, $callerOffset = 1, $level = E_USER_NOTICE ) {
1127         MWDebug::warning( $msg, $callerOffset + 1, $level, 'auto' );
1128 }
1129
1130 /**
1131  * Send a warning as a PHP error and the debug log. This is intended for logging
1132  * warnings in production. For logging development warnings, use WfWarn instead.
1133  *
1134  * @param string $msg Message to send
1135  * @param int $callerOffset Number of items to go back in the backtrace to
1136  *        find the correct caller (1 = function calling wfLogWarning, ...)
1137  * @param int $level PHP error level; defaults to E_USER_WARNING
1138  */
1139 function wfLogWarning( $msg, $callerOffset = 1, $level = E_USER_WARNING ) {
1140         MWDebug::warning( $msg, $callerOffset + 1, $level, 'production' );
1141 }
1142
1143 /**
1144  * Log to a file without getting "file size exceeded" signals.
1145  *
1146  * Can also log to TCP or UDP with the syntax udp://host:port/prefix. This will
1147  * send lines to the specified port, prefixed by the specified prefix and a space.
1148  *
1149  * @param string $text
1150  * @param string $file Filename
1151  * @throws MWException
1152  */
1153 function wfErrorLog( $text, $file ) {
1154         $logger = MWLogger::getInstance( 'wfErrorLog' );
1155         $logger->info( trim( $text ), array(
1156                 'destination' => $file,
1157         ) );
1158 }
1159
1160 /**
1161  * @todo document
1162  */
1163 function wfLogProfilingData() {
1164         global $wgRequestTime, $wgDebugLogGroups, $wgDebugRawPage;
1165         global $wgProfileLimit, $wgUser, $wgRequest;
1166
1167         StatCounter::singleton()->flush();
1168
1169         $profiler = Profiler::instance();
1170
1171         # Profiling must actually be enabled...
1172         if ( $profiler->isStub() ) {
1173                 return;
1174         }
1175
1176         // Get total page request time and only show pages that longer than
1177         // $wgProfileLimit time (default is 0)
1178         $elapsed = microtime( true ) - $wgRequestTime;
1179         if ( $elapsed <= $wgProfileLimit ) {
1180                 return;
1181         }
1182
1183         $profiler->logData();
1184
1185         if ( isset( $wgDebugLogGroups['profileoutput'] )
1186                 && $wgDebugLogGroups['profileoutput'] === false
1187         ) {
1188                 // Explicitly disabled
1189                 return;
1190         }
1191         if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
1192                 return;
1193         }
1194
1195         $ctx = array( 'elapsed' => $elapsed );
1196         if ( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
1197                 $ctx['forwarded_for'] = $_SERVER['HTTP_X_FORWARDED_FOR'];
1198         }
1199         if ( !empty( $_SERVER['HTTP_CLIENT_IP'] ) ) {
1200                 $ctx['client_ip'] = $_SERVER['HTTP_CLIENT_IP'];
1201         }
1202         if ( !empty( $_SERVER['HTTP_FROM'] ) ) {
1203                 $ctx['from'] = $_SERVER['HTTP_FROM'];
1204         }
1205         if ( isset( $ctx['forwarded_for'] ) ||
1206                 isset( $ctx['client_ip'] ) ||
1207                 isset( $ctx['from'] ) ) {
1208                 $ctx['proxy'] = $_SERVER['REMOTE_ADDR'];
1209         }
1210
1211         // Don't load $wgUser at this late stage just for statistics purposes
1212         // @todo FIXME: We can detect some anons even if it is not loaded.
1213         // See User::getId()
1214         if ( $wgUser->isItemLoaded( 'id' ) && $wgUser->isAnon() ) {
1215                 $ctx['anon'] = true;
1216         } else {
1217                 $ctx['anon'] = false;
1218         }
1219
1220         // Command line script uses a FauxRequest object which does not have
1221         // any knowledge about an URL and throw an exception instead.
1222         try {
1223                 $ctx['url'] = urldecode( $wgRequest->getRequestURL() );
1224         } catch ( MWException $ignored ) {
1225                 // no-op
1226         }
1227
1228         $ctx['output'] = $profiler->getOutput();
1229         $ctx['profile'] = $profiler->getRawData();
1230
1231         $log = MWLogger::getInstance( 'profileoutput' );
1232         $log->info( 'Elapsed: {elapsed}', $ctx );
1233 }
1234
1235 /**
1236  * Increment a statistics counter
1237  *
1238  * @param string $key
1239  * @param int $count
1240  * @return void
1241  */
1242 function wfIncrStats( $key, $count = 1 ) {
1243         StatCounter::singleton()->incr( $key, $count );
1244 }
1245
1246 /**
1247  * Check whether the wiki is in read-only mode.
1248  *
1249  * @return bool
1250  */
1251 function wfReadOnly() {
1252         return wfReadOnlyReason() !== false;
1253 }
1254
1255 /**
1256  * Get the value of $wgReadOnly or the contents of $wgReadOnlyFile.
1257  *
1258  * @return string|bool String when in read-only mode; false otherwise
1259  */
1260 function wfReadOnlyReason() {
1261         global $wgReadOnly, $wgReadOnlyFile;
1262
1263         if ( $wgReadOnly === null ) {
1264                 // Set $wgReadOnly for faster access next time
1265                 if ( is_file( $wgReadOnlyFile ) && filesize( $wgReadOnlyFile ) > 0 ) {
1266                         $wgReadOnly = file_get_contents( $wgReadOnlyFile );
1267                 } else {
1268                         $wgReadOnly = false;
1269                 }
1270         }
1271
1272         return $wgReadOnly;
1273 }
1274
1275 /**
1276  * Return a Language object from $langcode
1277  *
1278  * @param Language|string|bool $langcode Either:
1279  *                  - a Language object
1280  *                  - code of the language to get the message for, if it is
1281  *                    a valid code create a language for that language, if
1282  *                    it is a string but not a valid code then make a basic
1283  *                    language object
1284  *                  - a boolean: if it's false then use the global object for
1285  *                    the current user's language (as a fallback for the old parameter
1286  *                    functionality), or if it is true then use global object
1287  *                    for the wiki's content language.
1288  * @return Language
1289  */
1290 function wfGetLangObj( $langcode = false ) {
1291         # Identify which language to get or create a language object for.
1292         # Using is_object here due to Stub objects.
1293         if ( is_object( $langcode ) ) {
1294                 # Great, we already have the object (hopefully)!
1295                 return $langcode;
1296         }
1297
1298         global $wgContLang, $wgLanguageCode;
1299         if ( $langcode === true || $langcode === $wgLanguageCode ) {
1300                 # $langcode is the language code of the wikis content language object.
1301                 # or it is a boolean and value is true
1302                 return $wgContLang;
1303         }
1304
1305         global $wgLang;
1306         if ( $langcode === false || $langcode === $wgLang->getCode() ) {
1307                 # $langcode is the language code of user language object.
1308                 # or it was a boolean and value is false
1309                 return $wgLang;
1310         }
1311
1312         $validCodes = array_keys( Language::fetchLanguageNames() );
1313         if ( in_array( $langcode, $validCodes ) ) {
1314                 # $langcode corresponds to a valid language.
1315                 return Language::factory( $langcode );
1316         }
1317
1318         # $langcode is a string, but not a valid language code; use content language.
1319         wfDebug( "Invalid language code passed to wfGetLangObj, falling back to content language.\n" );
1320         return $wgContLang;
1321 }
1322
1323 /**
1324  * This is the function for getting translated interface messages.
1325  *
1326  * @see Message class for documentation how to use them.
1327  * @see https://www.mediawiki.org/wiki/Manual:Messages_API
1328  *
1329  * This function replaces all old wfMsg* functions.
1330  *
1331  * @param string|string[] $key Message key, or array of keys
1332  * @param mixed $params,... Normal message parameters
1333  * @return Message
1334  *
1335  * @since 1.17
1336  *
1337  * @see Message::__construct
1338  */
1339 function wfMessage( $key /*...*/ ) {
1340         $params = func_get_args();
1341         array_shift( $params );
1342         if ( isset( $params[0] ) && is_array( $params[0] ) ) {
1343                 $params = $params[0];
1344         }
1345         return new Message( $key, $params );
1346 }
1347
1348 /**
1349  * This function accepts multiple message keys and returns a message instance
1350  * for the first message which is non-empty. If all messages are empty then an
1351  * instance of the first message key is returned.
1352  *
1353  * @param string|string[] $keys,... Message keys
1354  * @return Message
1355  *
1356  * @since 1.18
1357  *
1358  * @see Message::newFallbackSequence
1359  */
1360 function wfMessageFallback( /*...*/ ) {
1361         $args = func_get_args();
1362         return call_user_func_array( 'Message::newFallbackSequence', $args );
1363 }
1364
1365 /**
1366  * Get a message from anywhere, for the current user language.
1367  *
1368  * Use wfMsgForContent() instead if the message should NOT
1369  * change depending on the user preferences.
1370  *
1371  * @deprecated since 1.18
1372  *
1373  * @param string $key Lookup key for the message, usually
1374  *    defined in languages/Language.php
1375  *
1376  * Parameters to the message, which can be used to insert variable text into
1377  * it, can be passed to this function in the following formats:
1378  * - One per argument, starting at the second parameter
1379  * - As an array in the second parameter
1380  * These are not shown in the function definition.
1381  *
1382  * @return string
1383  */
1384 function wfMsg( $key ) {
1385         wfDeprecated( __METHOD__, '1.21' );
1386
1387         $args = func_get_args();
1388         array_shift( $args );
1389         return wfMsgReal( $key, $args );
1390 }
1391
1392 /**
1393  * Same as above except doesn't transform the message
1394  *
1395  * @deprecated since 1.18
1396  *
1397  * @param string $key
1398  * @return string
1399  */
1400 function wfMsgNoTrans( $key ) {
1401         wfDeprecated( __METHOD__, '1.21' );
1402
1403         $args = func_get_args();
1404         array_shift( $args );
1405         return wfMsgReal( $key, $args, true, false, false );
1406 }
1407
1408 /**
1409  * Get a message from anywhere, for the current global language
1410  * set with $wgLanguageCode.
1411  *
1412  * Use this if the message should NOT change dependent on the
1413  * language set in the user's preferences. This is the case for
1414  * most text written into logs, as well as link targets (such as
1415  * the name of the copyright policy page). Link titles, on the
1416  * other hand, should be shown in the UI language.
1417  *
1418  * Note that MediaWiki allows users to change the user interface
1419  * language in their preferences, but a single installation
1420  * typically only contains content in one language.
1421  *
1422  * Be wary of this distinction: If you use wfMsg() where you should
1423  * use wfMsgForContent(), a user of the software may have to
1424  * customize potentially hundreds of messages in
1425  * order to, e.g., fix a link in every possible language.
1426  *
1427  * @deprecated since 1.18
1428  *
1429  * @param string $key Lookup key for the message, usually
1430  *     defined in languages/Language.php
1431  * @return string
1432  */
1433 function wfMsgForContent( $key ) {
1434         wfDeprecated( __METHOD__, '1.21' );
1435
1436         global $wgForceUIMsgAsContentMsg;
1437         $args = func_get_args();
1438         array_shift( $args );
1439         $forcontent = true;
1440         if ( is_array( $wgForceUIMsgAsContentMsg )
1441                 && in_array( $key, $wgForceUIMsgAsContentMsg )
1442         ) {
1443                 $forcontent = false;
1444         }
1445         return wfMsgReal( $key, $args, true, $forcontent );
1446 }
1447
1448 /**
1449  * Same as above except doesn't transform the message
1450  *
1451  * @deprecated since 1.18
1452  *
1453  * @param string $key
1454  * @return string
1455  */
1456 function wfMsgForContentNoTrans( $key ) {
1457         wfDeprecated( __METHOD__, '1.21' );
1458
1459         global $wgForceUIMsgAsContentMsg;
1460         $args = func_get_args();
1461         array_shift( $args );
1462         $forcontent = true;
1463         if ( is_array( $wgForceUIMsgAsContentMsg )
1464                 && in_array( $key, $wgForceUIMsgAsContentMsg )
1465         ) {
1466                 $forcontent = false;
1467         }
1468         return wfMsgReal( $key, $args, true, $forcontent, false );
1469 }
1470
1471 /**
1472  * Really get a message
1473  *
1474  * @deprecated since 1.18
1475  *
1476  * @param string $key Key to get.
1477  * @param array $args
1478  * @param bool $useDB
1479  * @param string|bool $forContent Language code, or false for user lang, true for content lang.
1480  * @param bool $transform Whether or not to transform the message.
1481  * @return string The requested message.
1482  */
1483 function wfMsgReal( $key, $args, $useDB = true, $forContent = false, $transform = true ) {
1484         wfDeprecated( __METHOD__, '1.21' );
1485
1486         wfProfileIn( __METHOD__ );
1487         $message = wfMsgGetKey( $key, $useDB, $forContent, $transform );
1488         $message = wfMsgReplaceArgs( $message, $args );
1489         wfProfileOut( __METHOD__ );
1490         return $message;
1491 }
1492
1493 /**
1494  * Fetch a message string value, but don't replace any keys yet.
1495  *
1496  * @deprecated since 1.18
1497  *
1498  * @param string $key
1499  * @param bool $useDB
1500  * @param string|bool $langCode Code of the language to get the message for, or
1501  *   behaves as a content language switch if it is a boolean.
1502  * @param bool $transform Whether to parse magic words, etc.
1503  * @return string
1504  */
1505 function wfMsgGetKey( $key, $useDB = true, $langCode = false, $transform = true ) {
1506         wfDeprecated( __METHOD__, '1.21' );
1507
1508         wfRunHooks( 'NormalizeMessageKey', array( &$key, &$useDB, &$langCode, &$transform ) );
1509
1510         $cache = MessageCache::singleton();
1511         $message = $cache->get( $key, $useDB, $langCode );
1512         if ( $message === false ) {
1513                 $message = '&lt;' . htmlspecialchars( $key ) . '&gt;';
1514         } elseif ( $transform ) {
1515                 $message = $cache->transform( $message );
1516         }
1517         return $message;
1518 }
1519
1520 /**
1521  * Replace message parameter keys on the given formatted output.
1522  *
1523  * @param string $message
1524  * @param array $args
1525  * @return string
1526  * @private
1527  */
1528 function wfMsgReplaceArgs( $message, $args ) {
1529         # Fix windows line-endings
1530         # Some messages are split with explode("\n", $msg)
1531         $message = str_replace( "\r", '', $message );
1532
1533         // Replace arguments
1534         if ( count( $args ) ) {
1535                 if ( is_array( $args[0] ) ) {
1536                         $args = array_values( $args[0] );
1537                 }
1538                 $replacementKeys = array();
1539                 foreach ( $args as $n => $param ) {
1540                         $replacementKeys['$' . ( $n + 1 )] = $param;
1541                 }
1542                 $message = strtr( $message, $replacementKeys );
1543         }
1544
1545         return $message;
1546 }
1547
1548 /**
1549  * Return an HTML-escaped version of a message.
1550  * Parameter replacements, if any, are done *after* the HTML-escaping,
1551  * so parameters may contain HTML (eg links or form controls). Be sure
1552  * to pre-escape them if you really do want plaintext, or just wrap
1553  * the whole thing in htmlspecialchars().
1554  *
1555  * @deprecated since 1.18
1556  *
1557  * @param string $key
1558  * @param string $args,... Parameters
1559  * @return string
1560  */
1561 function wfMsgHtml( $key ) {
1562         wfDeprecated( __METHOD__, '1.21' );
1563
1564         $args = func_get_args();
1565         array_shift( $args );
1566         return wfMsgReplaceArgs( htmlspecialchars( wfMsgGetKey( $key ) ), $args );
1567 }
1568
1569 /**
1570  * Return an HTML version of message
1571  * Parameter replacements, if any, are done *after* parsing the wiki-text message,
1572  * so parameters may contain HTML (eg links or form controls). Be sure
1573  * to pre-escape them if you really do want plaintext, or just wrap
1574  * the whole thing in htmlspecialchars().
1575  *
1576  * @deprecated since 1.18
1577  *
1578  * @param string $key
1579  * @param string $args,... Parameters
1580  * @return string
1581  */
1582 function wfMsgWikiHtml( $key ) {
1583         wfDeprecated( __METHOD__, '1.21' );
1584
1585         $args = func_get_args();
1586         array_shift( $args );
1587         return wfMsgReplaceArgs(
1588                 MessageCache::singleton()->parse( wfMsgGetKey( $key ), null,
1589                 /* can't be set to false */ true, /* interface */ true )->getText(),
1590                 $args );
1591 }
1592
1593 /**
1594  * Returns message in the requested format
1595  *
1596  * @deprecated since 1.18
1597  *
1598  * @param string $key Key of the message
1599  * @param array $options Processing rules.
1600  *   Can take the following options:
1601  *     parse: parses wikitext to HTML
1602  *     parseinline: parses wikitext to HTML and removes the surrounding
1603  *       p's added by parser or tidy
1604  *     escape: filters message through htmlspecialchars
1605  *     escapenoentities: same, but allows entity references like &#160; through
1606  *     replaceafter: parameters are substituted after parsing or escaping
1607  *     parsemag: transform the message using magic phrases
1608  *     content: fetch message for content language instead of interface
1609  *   Also can accept a single associative argument, of the form 'language' => 'xx':
1610  *     language: Language object or language code to fetch message for
1611  *       (overridden by content).
1612  * Behavior for conflicting options (e.g., parse+parseinline) is undefined.
1613  *
1614  * @return string
1615  */
1616 function wfMsgExt( $key, $options ) {
1617         wfDeprecated( __METHOD__, '1.21' );
1618
1619         $args = func_get_args();
1620         array_shift( $args );
1621         array_shift( $args );
1622         $options = (array)$options;
1623
1624         foreach ( $options as $arrayKey => $option ) {
1625                 if ( !preg_match( '/^[0-9]+|language$/', $arrayKey ) ) {
1626                         # An unknown index, neither numeric nor "language"
1627                         wfWarn( "wfMsgExt called with incorrect parameter key $arrayKey", 1, E_USER_WARNING );
1628                 } elseif ( preg_match( '/^[0-9]+$/', $arrayKey ) && !in_array( $option,
1629                 array( 'parse', 'parseinline', 'escape', 'escapenoentities',
1630                 'replaceafter', 'parsemag', 'content' ) ) ) {
1631                         # A numeric index with unknown value
1632                         wfWarn( "wfMsgExt called with incorrect parameter $option", 1, E_USER_WARNING );
1633                 }
1634         }
1635
1636         if ( in_array( 'content', $options, true ) ) {
1637                 $forContent = true;
1638                 $langCode = true;
1639                 $langCodeObj = null;
1640         } elseif ( array_key_exists( 'language', $options ) ) {
1641                 $forContent = false;
1642                 $langCode = wfGetLangObj( $options['language'] );
1643                 $langCodeObj = $langCode;
1644         } else {
1645                 $forContent = false;
1646                 $langCode = false;
1647                 $langCodeObj = null;
1648         }
1649
1650         $string = wfMsgGetKey( $key, /*DB*/true, $langCode, /*Transform*/false );
1651
1652         if ( !in_array( 'replaceafter', $options, true ) ) {
1653                 $string = wfMsgReplaceArgs( $string, $args );
1654         }
1655
1656         $messageCache = MessageCache::singleton();
1657         $parseInline = in_array( 'parseinline', $options, true );
1658         if ( in_array( 'parse', $options, true ) || $parseInline ) {
1659                 $string = $messageCache->parse( $string, null, true, !$forContent, $langCodeObj );
1660                 if ( $string instanceof ParserOutput ) {
1661                         $string = $string->getText();
1662                 }
1663
1664                 if ( $parseInline ) {
1665                         $string = Parser::stripOuterParagraph( $string );
1666                 }
1667         } elseif ( in_array( 'parsemag', $options, true ) ) {
1668                 $string = $messageCache->transform( $string,
1669                                 !$forContent, $langCodeObj );
1670         }
1671
1672         if ( in_array( 'escape', $options, true ) ) {
1673                 $string = htmlspecialchars ( $string );
1674         } elseif ( in_array( 'escapenoentities', $options, true ) ) {
1675                 $string = Sanitizer::escapeHtmlAllowEntities( $string );
1676         }
1677
1678         if ( in_array( 'replaceafter', $options, true ) ) {
1679                 $string = wfMsgReplaceArgs( $string, $args );
1680         }
1681
1682         return $string;
1683 }
1684
1685 /**
1686  * Since wfMsg() and co suck, they don't return false if the message key they
1687  * looked up didn't exist but instead the key wrapped in <>'s, this function checks for the
1688  * nonexistence of messages by checking the MessageCache::get() result directly.
1689  *
1690  * @deprecated since 1.18. Use Message::isDisabled().
1691  *
1692  * @param string $key The message key looked up
1693  * @return bool True if the message *doesn't* exist.
1694  */
1695 function wfEmptyMsg( $key ) {
1696         wfDeprecated( __METHOD__, '1.21' );
1697
1698         return MessageCache::singleton()->get( $key, /*useDB*/true, /*content*/false ) === false;
1699 }
1700
1701 /**
1702  * Fetch server name for use in error reporting etc.
1703  * Use real server name if available, so we know which machine
1704  * in a server farm generated the current page.
1705  *
1706  * @return string
1707  */
1708 function wfHostname() {
1709         static $host;
1710         if ( is_null( $host ) ) {
1711
1712                 # Hostname overriding
1713                 global $wgOverrideHostname;
1714                 if ( $wgOverrideHostname !== false ) {
1715                         # Set static and skip any detection
1716                         $host = $wgOverrideHostname;
1717                         return $host;
1718                 }
1719
1720                 if ( function_exists( 'posix_uname' ) ) {
1721                         // This function not present on Windows
1722                         $uname = posix_uname();
1723                 } else {
1724                         $uname = false;
1725                 }
1726                 if ( is_array( $uname ) && isset( $uname['nodename'] ) ) {
1727                         $host = $uname['nodename'];
1728                 } elseif ( getenv( 'COMPUTERNAME' ) ) {
1729                         # Windows computer name
1730                         $host = getenv( 'COMPUTERNAME' );
1731                 } else {
1732                         # This may be a virtual server.
1733                         $host = $_SERVER['SERVER_NAME'];
1734                 }
1735         }
1736         return $host;
1737 }
1738
1739 /**
1740  * Returns a script tag that stores the amount of time it took MediaWiki to
1741  * handle the request in milliseconds as 'wgBackendResponseTime'.
1742  *
1743  * If $wgShowHostnames is true, the script will also set 'wgHostname' to the
1744  * hostname of the server handling the request.
1745  *
1746  * @return string
1747  */
1748 function wfReportTime() {
1749         global $wgRequestTime, $wgShowHostnames;
1750
1751         $responseTime = round( ( microtime( true ) - $wgRequestTime ) * 1000 );
1752         $reportVars = array( 'wgBackendResponseTime' => $responseTime );
1753         if ( $wgShowHostnames ) {
1754                 $reportVars['wgHostname'] = wfHostname();
1755         }
1756         return Skin::makeVariablesScript( $reportVars );
1757 }
1758
1759 /**
1760  * Safety wrapper for debug_backtrace().
1761  *
1762  * Will return an empty array if debug_backtrace is disabled, otherwise
1763  * the output from debug_backtrace() (trimmed).
1764  *
1765  * @param int $limit This parameter can be used to limit the number of stack frames returned
1766  *
1767  * @return array Array of backtrace information
1768  */
1769 function wfDebugBacktrace( $limit = 0 ) {
1770         static $disabled = null;
1771
1772         if ( is_null( $disabled ) ) {
1773                 $disabled = !function_exists( 'debug_backtrace' );
1774                 if ( $disabled ) {
1775                         wfDebug( "debug_backtrace() is disabled\n" );
1776                 }
1777         }
1778         if ( $disabled ) {
1779                 return array();
1780         }
1781
1782         if ( $limit && version_compare( PHP_VERSION, '5.4.0', '>=' ) ) {
1783                 return array_slice( debug_backtrace( DEBUG_BACKTRACE_PROVIDE_OBJECT, $limit + 1 ), 1 );
1784         } else {
1785                 return array_slice( debug_backtrace(), 1 );
1786         }
1787 }
1788
1789 /**
1790  * Get a debug backtrace as a string
1791  *
1792  * @param bool|null $raw If true, the return value is plain text. If false, HTML.
1793  *   Defaults to $wgCommandLineMode if unset.
1794  * @return string
1795  * @since 1.25 Supports $raw parameter.
1796  */
1797 function wfBacktrace( $raw = null ) {
1798         global $wgCommandLineMode;
1799
1800         if ( $raw === null ) {
1801                 $raw = $wgCommandLineMode;
1802         }
1803
1804         if ( $raw ) {
1805                 $frameFormat = "%s line %s calls %s()\n";
1806                 $traceFormat = "%s";
1807         } else {
1808                 $frameFormat = "<li>%s line %s calls %s()</li>\n";
1809                 $traceFormat = "<ul>\n%s</ul>\n";
1810         }
1811
1812         $frames = array_map( function ( $frame ) use ( $frameFormat ) {
1813                 $file = !empty( $frame['file'] ) ? basename( $frame['file'] ) : '-';
1814                 $line = $frame['line'] ?: '-';
1815                 $call = $frame['function'];
1816                 if ( !empty( $frame['class'] ) ) {
1817                         $call = $frame['class'] . $frame['type'] . $call;
1818                 }
1819                 return sprintf( $frameFormat, $file, $line, $call );
1820         }, wfDebugBacktrace() );
1821
1822         return sprintf( $traceFormat, implode( '', $frames ) );
1823 }
1824
1825 /**
1826  * Get the name of the function which called this function
1827  * wfGetCaller( 1 ) is the function with the wfGetCaller() call (ie. __FUNCTION__)
1828  * wfGetCaller( 2 ) [default] is the caller of the function running wfGetCaller()
1829  * wfGetCaller( 3 ) is the parent of that.
1830  *
1831  * @param int $level
1832  * @return string
1833  */
1834 function wfGetCaller( $level = 2 ) {
1835         $backtrace = wfDebugBacktrace( $level + 1 );
1836         if ( isset( $backtrace[$level] ) ) {
1837                 return wfFormatStackFrame( $backtrace[$level] );
1838         } else {
1839                 return 'unknown';
1840         }
1841 }
1842
1843 /**
1844  * Return a string consisting of callers in the stack. Useful sometimes
1845  * for profiling specific points.
1846  *
1847  * @param int $limit The maximum depth of the stack frame to return, or false for the entire stack.
1848  * @return string
1849  */
1850 function wfGetAllCallers( $limit = 3 ) {
1851         $trace = array_reverse( wfDebugBacktrace() );
1852         if ( !$limit || $limit > count( $trace ) - 1 ) {
1853                 $limit = count( $trace ) - 1;
1854         }
1855         $trace = array_slice( $trace, -$limit - 1, $limit );
1856         return implode( '/', array_map( 'wfFormatStackFrame', $trace ) );
1857 }
1858
1859 /**
1860  * Return a string representation of frame
1861  *
1862  * @param array $frame
1863  * @return string
1864  */
1865 function wfFormatStackFrame( $frame ) {
1866         return isset( $frame['class'] ) ?
1867                 $frame['class'] . '::' . $frame['function'] :
1868                 $frame['function'];
1869 }
1870
1871 /* Some generic result counters, pulled out of SearchEngine */
1872
1873 /**
1874  * @todo document
1875  *
1876  * @param int $offset
1877  * @param int $limit
1878  * @return string
1879  */
1880 function wfShowingResults( $offset, $limit ) {
1881         return wfMessage( 'showingresults' )->numParams( $limit, $offset + 1 )->parse();
1882 }
1883
1884 /**
1885  * @todo document
1886  * @todo FIXME: We may want to blacklist some broken browsers
1887  *
1888  * @param bool $force
1889  * @return bool Whereas client accept gzip compression
1890  */
1891 function wfClientAcceptsGzip( $force = false ) {
1892         static $result = null;
1893         if ( $result === null || $force ) {
1894                 $result = false;
1895                 if ( isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ) {
1896                         # @todo FIXME: We may want to blacklist some broken browsers
1897                         $m = array();
1898                         if ( preg_match(
1899                                         '/\bgzip(?:;(q)=([0-9]+(?:\.[0-9]+)))?\b/',
1900                                         $_SERVER['HTTP_ACCEPT_ENCODING'],
1901                                         $m
1902                                 )
1903                         ) {
1904                                 if ( isset( $m[2] ) && ( $m[1] == 'q' ) && ( $m[2] == 0 ) ) {
1905                                         $result = false;
1906                                         return $result;
1907                                 }
1908                                 wfDebug( "wfClientAcceptsGzip: client accepts gzip.\n" );
1909                                 $result = true;
1910                         }
1911                 }
1912         }
1913         return $result;
1914 }
1915
1916 /**
1917  * Obtain the offset and limit values from the request string;
1918  * used in special pages
1919  *
1920  * @param int $deflimit Default limit if none supplied
1921  * @param string $optionname Name of a user preference to check against
1922  * @return array
1923  * @deprecated since 1.24, just call WebRequest::getLimitOffset() directly
1924  */
1925 function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
1926         global $wgRequest;
1927         wfDeprecated( __METHOD__, '1.24' );
1928         return $wgRequest->getLimitOffset( $deflimit, $optionname );
1929 }
1930
1931 /**
1932  * Escapes the given text so that it may be output using addWikiText()
1933  * without any linking, formatting, etc. making its way through. This
1934  * is achieved by substituting certain characters with HTML entities.
1935  * As required by the callers, "<nowiki>" is not used.
1936  *
1937  * @param string $text Text to be escaped
1938  * @return string
1939  */
1940 function wfEscapeWikiText( $text ) {
1941         static $repl = null, $repl2 = null;
1942         if ( $repl === null ) {
1943                 $repl = array(
1944                         '"' => '&#34;', '&' => '&#38;', "'" => '&#39;', '<' => '&#60;',
1945                         '=' => '&#61;', '>' => '&#62;', '[' => '&#91;', ']' => '&#93;',
1946                         '{' => '&#123;', '|' => '&#124;', '}' => '&#125;', ';' => '&#59;',
1947                         "\n#" => "\n&#35;", "\r#" => "\r&#35;",
1948                         "\n*" => "\n&#42;", "\r*" => "\r&#42;",
1949                         "\n:" => "\n&#58;", "\r:" => "\r&#58;",
1950                         "\n " => "\n&#32;", "\r " => "\r&#32;",
1951                         "\n\n" => "\n&#10;", "\r\n" => "&#13;\n",
1952                         "\n\r" => "\n&#13;", "\r\r" => "\r&#13;",
1953                         "\n\t" => "\n&#9;", "\r\t" => "\r&#9;", // "\n\t\n" is treated like "\n\n"
1954                         "\n----" => "\n&#45;---", "\r----" => "\r&#45;---",
1955                         '__' => '_&#95;', '://' => '&#58;//',
1956                 );
1957
1958                 // We have to catch everything "\s" matches in PCRE
1959                 foreach ( array( 'ISBN', 'RFC', 'PMID' ) as $magic ) {
1960                         $repl["$magic "] = "$magic&#32;";
1961                         $repl["$magic\t"] = "$magic&#9;";
1962                         $repl["$magic\r"] = "$magic&#13;";
1963                         $repl["$magic\n"] = "$magic&#10;";
1964                         $repl["$magic\f"] = "$magic&#12;";
1965                 }
1966
1967                 // And handle protocols that don't use "://"
1968                 global $wgUrlProtocols;
1969                 $repl2 = array();
1970                 foreach ( $wgUrlProtocols as $prot ) {
1971                         if ( substr( $prot, -1 ) === ':' ) {
1972                                 $repl2[] = preg_quote( substr( $prot, 0, -1 ), '/' );
1973                         }
1974                 }
1975                 $repl2 = $repl2 ? '/\b(' . join( '|', $repl2 ) . '):/i' : '/^(?!)/';
1976         }
1977         $text = substr( strtr( "\n$text", $repl ), 1 );
1978         $text = preg_replace( $repl2, '$1&#58;', $text );
1979         return $text;
1980 }
1981
1982 /**
1983  * Sets dest to source and returns the original value of dest
1984  * If source is NULL, it just returns the value, it doesn't set the variable
1985  * If force is true, it will set the value even if source is NULL
1986  *
1987  * @param mixed $dest
1988  * @param mixed $source
1989  * @param bool $force
1990  * @return mixed
1991  */
1992 function wfSetVar( &$dest, $source, $force = false ) {
1993         $temp = $dest;
1994         if ( !is_null( $source ) || $force ) {
1995                 $dest = $source;
1996         }
1997         return $temp;
1998 }
1999
2000 /**
2001  * As for wfSetVar except setting a bit
2002  *
2003  * @param int $dest
2004  * @param int $bit
2005  * @param bool $state
2006  *
2007  * @return bool
2008  */
2009 function wfSetBit( &$dest, $bit, $state = true ) {
2010         $temp = (bool)( $dest & $bit );
2011         if ( !is_null( $state ) ) {
2012                 if ( $state ) {
2013                         $dest |= $bit;
2014                 } else {
2015                         $dest &= ~$bit;
2016                 }
2017         }
2018         return $temp;
2019 }
2020
2021 /**
2022  * A wrapper around the PHP function var_export().
2023  * Either print it or add it to the regular output ($wgOut).
2024  *
2025  * @param mixed $var A PHP variable to dump.
2026  */
2027 function wfVarDump( $var ) {
2028         global $wgOut;
2029         $s = str_replace( "\n", "<br />\n", var_export( $var, true ) . "\n" );
2030         if ( headers_sent() || !isset( $wgOut ) || !is_object( $wgOut ) ) {
2031                 print $s;
2032         } else {
2033                 $wgOut->addHTML( $s );
2034         }
2035 }
2036
2037 /**
2038  * Provide a simple HTTP error.
2039  *
2040  * @param int|string $code
2041  * @param string $label
2042  * @param string $desc
2043  */
2044 function wfHttpError( $code, $label, $desc ) {
2045         global $wgOut;
2046         $wgOut->disable();
2047         header( "HTTP/1.0 $code $label" );
2048         header( "Status: $code $label" );
2049         $wgOut->sendCacheControl();
2050
2051         header( 'Content-type: text/html; charset=utf-8' );
2052         print "<!doctype html>" .
2053                 '<html><head><title>' .
2054                 htmlspecialchars( $label ) .
2055                 '</title></head><body><h1>' .
2056                 htmlspecialchars( $label ) .
2057                 '</h1><p>' .
2058                 nl2br( htmlspecialchars( $desc ) ) .
2059                 "</p></body></html>\n";
2060 }
2061
2062 /**
2063  * Clear away any user-level output buffers, discarding contents.
2064  *
2065  * Suitable for 'starting afresh', for instance when streaming
2066  * relatively large amounts of data without buffering, or wanting to
2067  * output image files without ob_gzhandler's compression.
2068  *
2069  * The optional $resetGzipEncoding parameter controls suppression of
2070  * the Content-Encoding header sent by ob_gzhandler; by default it
2071  * is left. See comments for wfClearOutputBuffers() for why it would
2072  * be used.
2073  *
2074  * Note that some PHP configuration options may add output buffer
2075  * layers which cannot be removed; these are left in place.
2076  *
2077  * @param bool $resetGzipEncoding
2078  */
2079 function wfResetOutputBuffers( $resetGzipEncoding = true ) {
2080         if ( $resetGzipEncoding ) {
2081                 // Suppress Content-Encoding and Content-Length
2082                 // headers from 1.10+s wfOutputHandler
2083                 global $wgDisableOutputCompression;
2084                 $wgDisableOutputCompression = true;
2085         }
2086         while ( $status = ob_get_status() ) {
2087                 if ( $status['type'] == 0 /* PHP_OUTPUT_HANDLER_INTERNAL */ ) {
2088                         // Probably from zlib.output_compression or other
2089                         // PHP-internal setting which can't be removed.
2090                         //
2091                         // Give up, and hope the result doesn't break
2092                         // output behavior.
2093                         break;
2094                 }
2095                 if ( !ob_end_clean() ) {
2096                         // Could not remove output buffer handler; abort now
2097                         // to avoid getting in some kind of infinite loop.
2098                         break;
2099                 }
2100                 if ( $resetGzipEncoding ) {
2101                         if ( $status['name'] == 'ob_gzhandler' ) {
2102                                 // Reset the 'Content-Encoding' field set by this handler
2103                                 // so we can start fresh.
2104                                 header_remove( 'Content-Encoding' );
2105                                 break;
2106                         }
2107                 }
2108         }
2109 }
2110
2111 /**
2112  * More legible than passing a 'false' parameter to wfResetOutputBuffers():
2113  *
2114  * Clear away output buffers, but keep the Content-Encoding header
2115  * produced by ob_gzhandler, if any.
2116  *
2117  * This should be used for HTTP 304 responses, where you need to
2118  * preserve the Content-Encoding header of the real result, but
2119  * also need to suppress the output of ob_gzhandler to keep to spec
2120  * and avoid breaking Firefox in rare cases where the headers and
2121  * body are broken over two packets.
2122  */
2123 function wfClearOutputBuffers() {
2124         wfResetOutputBuffers( false );
2125 }
2126
2127 /**
2128  * Converts an Accept-* header into an array mapping string values to quality
2129  * factors
2130  *
2131  * @param string $accept
2132  * @param string $def Default
2133  * @return float[] Associative array of string => float pairs
2134  */
2135 function wfAcceptToPrefs( $accept, $def = '*/*' ) {
2136         # No arg means accept anything (per HTTP spec)
2137         if ( !$accept ) {
2138                 return array( $def => 1.0 );
2139         }
2140
2141         $prefs = array();
2142
2143         $parts = explode( ',', $accept );
2144
2145         foreach ( $parts as $part ) {
2146                 # @todo FIXME: Doesn't deal with params like 'text/html; level=1'
2147                 $values = explode( ';', trim( $part ) );
2148                 $match = array();
2149                 if ( count( $values ) == 1 ) {
2150                         $prefs[$values[0]] = 1.0;
2151                 } elseif ( preg_match( '/q\s*=\s*(\d*\.\d+)/', $values[1], $match ) ) {
2152                         $prefs[$values[0]] = floatval( $match[1] );
2153                 }
2154         }
2155
2156         return $prefs;
2157 }
2158
2159 /**
2160  * Checks if a given MIME type matches any of the keys in the given
2161  * array. Basic wildcards are accepted in the array keys.
2162  *
2163  * Returns the matching MIME type (or wildcard) if a match, otherwise
2164  * NULL if no match.
2165  *
2166  * @param string $type
2167  * @param array $avail
2168  * @return string
2169  * @private
2170  */
2171 function mimeTypeMatch( $type, $avail ) {
2172         if ( array_key_exists( $type, $avail ) ) {
2173                 return $type;
2174         } else {
2175                 $parts = explode( '/', $type );
2176                 if ( array_key_exists( $parts[0] . '/*', $avail ) ) {
2177                         return $parts[0] . '/*';
2178                 } elseif ( array_key_exists( '*/*', $avail ) ) {
2179                         return '*/*';
2180                 } else {
2181                         return null;
2182                 }
2183         }
2184 }
2185
2186 /**
2187  * Returns the 'best' match between a client's requested internet media types
2188  * and the server's list of available types. Each list should be an associative
2189  * array of type to preference (preference is a float between 0.0 and 1.0).
2190  * Wildcards in the types are acceptable.
2191  *
2192  * @param array $cprefs Client's acceptable type list
2193  * @param array $sprefs Server's offered types
2194  * @return string
2195  *
2196  * @todo FIXME: Doesn't handle params like 'text/plain; charset=UTF-8'
2197  * XXX: generalize to negotiate other stuff
2198  */
2199 function wfNegotiateType( $cprefs, $sprefs ) {
2200         $combine = array();
2201
2202         foreach ( array_keys( $sprefs ) as $type ) {
2203                 $parts = explode( '/', $type );
2204                 if ( $parts[1] != '*' ) {
2205                         $ckey = mimeTypeMatch( $type, $cprefs );
2206                         if ( $ckey ) {
2207                                 $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
2208                         }
2209                 }
2210         }
2211
2212         foreach ( array_keys( $cprefs ) as $type ) {
2213                 $parts = explode( '/', $type );
2214                 if ( $parts[1] != '*' && !array_key_exists( $type, $sprefs ) ) {
2215                         $skey = mimeTypeMatch( $type, $sprefs );
2216                         if ( $skey ) {
2217                                 $combine[$type] = $sprefs[$skey] * $cprefs[$type];
2218                         }
2219                 }
2220         }
2221
2222         $bestq = 0;
2223         $besttype = null;
2224
2225         foreach ( array_keys( $combine ) as $type ) {
2226                 if ( $combine[$type] > $bestq ) {
2227                         $besttype = $type;
2228                         $bestq = $combine[$type];
2229                 }
2230         }
2231
2232         return $besttype;
2233 }
2234
2235 /**
2236  * Reference-counted warning suppression
2237  *
2238  * @param bool $end
2239  */
2240 function wfSuppressWarnings( $end = false ) {
2241         static $suppressCount = 0;
2242         static $originalLevel = false;
2243
2244         if ( $end ) {
2245                 if ( $suppressCount ) {
2246                         --$suppressCount;
2247                         if ( !$suppressCount ) {
2248                                 error_reporting( $originalLevel );
2249                         }
2250                 }
2251         } else {
2252                 if ( !$suppressCount ) {
2253                         $originalLevel = error_reporting( E_ALL & ~(
2254                                 E_WARNING |
2255                                 E_NOTICE |
2256                                 E_USER_WARNING |
2257                                 E_USER_NOTICE |
2258                                 E_DEPRECATED |
2259                                 E_USER_DEPRECATED |
2260                                 E_STRICT
2261                         ) );
2262                 }
2263                 ++$suppressCount;
2264         }
2265 }
2266
2267 /**
2268  * Restore error level to previous value
2269  */
2270 function wfRestoreWarnings() {
2271         wfSuppressWarnings( true );
2272 }
2273
2274 # Autodetect, convert and provide timestamps of various types
2275
2276 /**
2277  * Unix time - the number of seconds since 1970-01-01 00:00:00 UTC
2278  */
2279 define( 'TS_UNIX', 0 );
2280
2281 /**
2282  * MediaWiki concatenated string timestamp (YYYYMMDDHHMMSS)
2283  */
2284 define( 'TS_MW', 1 );
2285
2286 /**
2287  * MySQL DATETIME (YYYY-MM-DD HH:MM:SS)
2288  */
2289 define( 'TS_DB', 2 );
2290
2291 /**
2292  * RFC 2822 format, for E-mail and HTTP headers
2293  */
2294 define( 'TS_RFC2822', 3 );
2295
2296 /**
2297  * ISO 8601 format with no timezone: 1986-02-09T20:00:00Z
2298  *
2299  * This is used by Special:Export
2300  */
2301 define( 'TS_ISO_8601', 4 );
2302
2303 /**
2304  * An Exif timestamp (YYYY:MM:DD HH:MM:SS)
2305  *
2306  * @see http://exif.org/Exif2-2.PDF The Exif 2.2 spec, see page 28 for the
2307  *       DateTime tag and page 36 for the DateTimeOriginal and
2308  *       DateTimeDigitized tags.
2309  */
2310 define( 'TS_EXIF', 5 );
2311
2312 /**
2313  * Oracle format time.
2314  */
2315 define( 'TS_ORACLE', 6 );
2316
2317 /**
2318  * Postgres format time.
2319  */
2320 define( 'TS_POSTGRES', 7 );
2321
2322 /**
2323  * ISO 8601 basic format with no timezone: 19860209T200000Z.  This is used by ResourceLoader
2324  */
2325 define( 'TS_ISO_8601_BASIC', 9 );
2326
2327 /**
2328  * Get a timestamp string in one of various formats
2329  *
2330  * @param mixed $outputtype A timestamp in one of the supported formats, the
2331  *   function will autodetect which format is supplied and act accordingly.
2332  * @param mixed $ts Optional timestamp to convert, default 0 for the current time
2333  * @return string|bool String / false The same date in the format specified in $outputtype or false
2334  */
2335 function wfTimestamp( $outputtype = TS_UNIX, $ts = 0 ) {
2336         try {
2337                 $timestamp = new MWTimestamp( $ts );
2338                 return $timestamp->getTimestamp( $outputtype );
2339         } catch ( TimestampException $e ) {
2340                 wfDebug( "wfTimestamp() fed bogus time value: TYPE=$outputtype; VALUE=$ts\n" );
2341                 return false;
2342         }
2343 }
2344
2345 /**
2346  * Return a formatted timestamp, or null if input is null.
2347  * For dealing with nullable timestamp columns in the database.
2348  *
2349  * @param int $outputtype
2350  * @param string $ts
2351  * @return string
2352  */
2353 function wfTimestampOrNull( $outputtype = TS_UNIX, $ts = null ) {
2354         if ( is_null( $ts ) ) {
2355                 return null;
2356         } else {
2357                 return wfTimestamp( $outputtype, $ts );
2358         }
2359 }
2360
2361 /**
2362  * Convenience function; returns MediaWiki timestamp for the present time.
2363  *
2364  * @return string
2365  */
2366 function wfTimestampNow() {
2367         # return NOW
2368         return wfTimestamp( TS_MW, time() );
2369 }
2370
2371 /**
2372  * Check if the operating system is Windows
2373  *
2374  * @return bool True if it's Windows, false otherwise.
2375  */
2376 function wfIsWindows() {
2377         static $isWindows = null;
2378         if ( $isWindows === null ) {
2379                 $isWindows = substr( php_uname(), 0, 7 ) == 'Windows';
2380         }
2381         return $isWindows;
2382 }
2383
2384 /**
2385  * Check if we are running under HHVM
2386  *
2387  * @return bool
2388  */
2389 function wfIsHHVM() {
2390         return defined( 'HHVM_VERSION' );
2391 }
2392
2393 /**
2394  * Swap two variables
2395  *
2396  * @deprecated since 1.24
2397  * @param mixed $x
2398  * @param mixed $y
2399  */
2400 function swap( &$x, &$y ) {
2401         wfDeprecated( __FUNCTION__, '1.24' );
2402         $z = $x;
2403         $x = $y;
2404         $y = $z;
2405 }
2406
2407 /**
2408  * Tries to get the system directory for temporary files. First
2409  * $wgTmpDirectory is checked, and then the TMPDIR, TMP, and TEMP
2410  * environment variables are then checked in sequence, and if none are
2411  * set try sys_get_temp_dir().
2412  *
2413  * NOTE: When possible, use instead the tmpfile() function to create
2414  * temporary files to avoid race conditions on file creation, etc.
2415  *
2416  * @return string
2417  */
2418 function wfTempDir() {
2419         global $wgTmpDirectory;
2420
2421         if ( $wgTmpDirectory !== false ) {
2422                 return $wgTmpDirectory;
2423         }
2424
2425         $tmpDir = array_map( "getenv", array( 'TMPDIR', 'TMP', 'TEMP' ) );
2426
2427         foreach ( $tmpDir as $tmp ) {
2428                 if ( $tmp && file_exists( $tmp ) && is_dir( $tmp ) && is_writable( $tmp ) ) {
2429                         return $tmp;
2430                 }
2431         }
2432         return sys_get_temp_dir();
2433 }
2434
2435 /**
2436  * Make directory, and make all parent directories if they don't exist
2437  *
2438  * @param string $dir Full path to directory to create
2439  * @param int $mode Chmod value to use, default is $wgDirectoryMode
2440  * @param string $caller Optional caller param for debugging.
2441  * @throws MWException
2442  * @return bool
2443  */
2444 function wfMkdirParents( $dir, $mode = null, $caller = null ) {
2445         global $wgDirectoryMode;
2446
2447         if ( FileBackend::isStoragePath( $dir ) ) { // sanity
2448                 throw new MWException( __FUNCTION__ . " given storage path '$dir'." );
2449         }
2450
2451         if ( !is_null( $caller ) ) {
2452                 wfDebug( "$caller: called wfMkdirParents($dir)\n" );
2453         }
2454
2455         if ( strval( $dir ) === '' || ( file_exists( $dir ) && is_dir( $dir ) ) ) {
2456                 return true;
2457         }
2458
2459         $dir = str_replace( array( '\\', '/' ), DIRECTORY_SEPARATOR, $dir );
2460
2461         if ( is_null( $mode ) ) {
2462                 $mode = $wgDirectoryMode;
2463         }
2464
2465         // Turn off the normal warning, we're doing our own below
2466         wfSuppressWarnings();
2467         $ok = mkdir( $dir, $mode, true ); // PHP5 <3
2468         wfRestoreWarnings();
2469
2470         if ( !$ok ) {
2471                 //directory may have been created on another request since we last checked
2472                 if ( is_dir( $dir ) ) {
2473                         return true;
2474                 }
2475
2476                 // PHP doesn't report the path in its warning message, so add our own to aid in diagnosis.
2477                 wfLogWarning( sprintf( "failed to mkdir \"%s\" mode 0%o", $dir, $mode ) );
2478         }
2479         return $ok;
2480 }
2481
2482 /**
2483  * Remove a directory and all its content.
2484  * Does not hide error.
2485  * @param string $dir
2486  */
2487 function wfRecursiveRemoveDir( $dir ) {
2488         wfDebug( __FUNCTION__ . "( $dir )\n" );
2489         // taken from http://de3.php.net/manual/en/function.rmdir.php#98622
2490         if ( is_dir( $dir ) ) {
2491                 $objects = scandir( $dir );
2492                 foreach ( $objects as $object ) {
2493                         if ( $object != "." && $object != ".." ) {
2494                                 if ( filetype( $dir . '/' . $object ) == "dir" ) {
2495                                         wfRecursiveRemoveDir( $dir . '/' . $object );
2496                                 } else {
2497                                         unlink( $dir . '/' . $object );
2498                                 }
2499                         }
2500                 }
2501                 reset( $objects );
2502                 rmdir( $dir );
2503         }
2504 }
2505
2506 /**
2507  * @param int $nr The number to format
2508  * @param int $acc The number of digits after the decimal point, default 2
2509  * @param bool $round Whether or not to round the value, default true
2510  * @return string
2511  */
2512 function wfPercent( $nr, $acc = 2, $round = true ) {
2513         $ret = sprintf( "%.${acc}f", $nr );
2514         return $round ? round( $ret, $acc ) . '%' : "$ret%";
2515 }
2516
2517 /**
2518  * Safety wrapper around ini_get() for boolean settings.
2519  * The values returned from ini_get() are pre-normalized for settings
2520  * set via php.ini or php_flag/php_admin_flag... but *not*
2521  * for those set via php_value/php_admin_value.
2522  *
2523  * It's fairly common for people to use php_value instead of php_flag,
2524  * which can leave you with an 'off' setting giving a false positive
2525  * for code that just takes the ini_get() return value as a boolean.
2526  *
2527  * To make things extra interesting, setting via php_value accepts
2528  * "true" and "yes" as true, but php.ini and php_flag consider them false. :)
2529  * Unrecognized values go false... again opposite PHP's own coercion
2530  * from string to bool.
2531  *
2532  * Luckily, 'properly' set settings will always come back as '0' or '1',
2533  * so we only have to worry about them and the 'improper' settings.
2534  *
2535  * I frickin' hate PHP... :P
2536  *
2537  * @param string $setting
2538  * @return bool
2539  */
2540 function wfIniGetBool( $setting ) {
2541         $val = strtolower( ini_get( $setting ) );
2542         // 'on' and 'true' can't have whitespace around them, but '1' can.
2543         return $val == 'on'
2544                 || $val == 'true'
2545                 || $val == 'yes'
2546                 || preg_match( "/^\s*[+-]?0*[1-9]/", $val ); // approx C atoi() function
2547 }
2548
2549 /**
2550  * Windows-compatible version of escapeshellarg()
2551  * Windows doesn't recognise single-quotes in the shell, but the escapeshellarg()
2552  * function puts single quotes in regardless of OS.
2553  *
2554  * Also fixes the locale problems on Linux in PHP 5.2.6+ (bug backported to
2555  * earlier distro releases of PHP)
2556  *
2557  * @param string $args,...
2558  * @return string
2559  */
2560 function wfEscapeShellArg( /*...*/ ) {
2561         wfInitShellLocale();
2562
2563         $args = func_get_args();
2564         $first = true;
2565         $retVal = '';
2566         foreach ( $args as $arg ) {
2567                 if ( !$first ) {
2568                         $retVal .= ' ';
2569                 } else {
2570                         $first = false;
2571                 }
2572
2573                 if ( wfIsWindows() ) {
2574                         // Escaping for an MSVC-style command line parser and CMD.EXE
2575                         // @codingStandardsIgnoreStart For long URLs
2576                         // Refs:
2577                         //  * http://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
2578                         //  * http://technet.microsoft.com/en-us/library/cc723564.aspx
2579                         //  * Bug #13518
2580                         //  * CR r63214
2581                         // Double the backslashes before any double quotes. Escape the double quotes.
2582                         // @codingStandardsIgnoreEnd
2583                         $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
2584                         $arg = '';
2585                         $iteration = 0;
2586                         foreach ( $tokens as $token ) {
2587                                 if ( $iteration % 2 == 1 ) {
2588                                         // Delimiter, a double quote preceded by zero or more slashes
2589                                         $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
2590                                 } elseif ( $iteration % 4 == 2 ) {
2591                                         // ^ in $token will be outside quotes, need to be escaped
2592                                         $arg .= str_replace( '^', '^^', $token );
2593                                 } else { // $iteration % 4 == 0
2594                                         // ^ in $token will appear inside double quotes, so leave as is
2595                                         $arg .= $token;
2596                                 }
2597                                 $iteration++;
2598                         }
2599                         // Double the backslashes before the end of the string, because
2600                         // we will soon add a quote
2601                         $m = array();
2602                         if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
2603                                 $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
2604                         }
2605
2606                         // Add surrounding quotes
2607                         $retVal .= '"' . $arg . '"';
2608                 } else {
2609                         $retVal .= escapeshellarg( $arg );
2610                 }
2611         }
2612         return $retVal;
2613 }
2614
2615 /**
2616  * Check if wfShellExec() is effectively disabled via php.ini config
2617  *
2618  * @return bool|string False or one of (safemode,disabled)
2619  * @since 1.22
2620  */
2621 function wfShellExecDisabled() {
2622         static $disabled = null;
2623         if ( is_null( $disabled ) ) {
2624                 if ( wfIniGetBool( 'safe_mode' ) ) {
2625                         wfDebug( "wfShellExec can't run in safe_mode, PHP's exec functions are too broken.\n" );
2626                         $disabled = 'safemode';
2627                 } elseif ( !function_exists( 'proc_open' ) ) {
2628                         wfDebug( "proc_open() is disabled\n" );
2629                         $disabled = 'disabled';
2630                 } else {
2631                         $disabled = false;
2632                 }
2633         }
2634         return $disabled;
2635 }
2636
2637 /**
2638  * Execute a shell command, with time and memory limits mirrored from the PHP
2639  * configuration if supported.
2640  *
2641  * @param string|string[] $cmd If string, a properly shell-escaped command line,
2642  *   or an array of unescaped arguments, in which case each value will be escaped
2643  *   Example:   [ 'convert', '-font', 'font name' ] would produce "'convert' '-font' 'font name'"
2644  * @param null|mixed &$retval Optional, will receive the program's exit code.
2645  *   (non-zero is usually failure). If there is an error from
2646  *   read, select, or proc_open(), this will be set to -1.
2647  * @param array $environ Optional environment variables which should be
2648  *   added to the executed command environment.
2649  * @param array $limits Optional array with limits(filesize, memory, time, walltime)
2650  *   this overwrites the global wgMaxShell* limits.
2651  * @param array $options Array of options:
2652  *   - duplicateStderr: Set this to true to duplicate stderr to stdout,
2653  *     including errors from limit.sh
2654  *
2655  * @return string Collected stdout as a string
2656  */
2657 function wfShellExec( $cmd, &$retval = null, $environ = array(),
2658         $limits = array(), $options = array()
2659 ) {
2660         global $IP, $wgMaxShellMemory, $wgMaxShellFileSize, $wgMaxShellTime,
2661                 $wgMaxShellWallClockTime, $wgShellCgroup;
2662
2663         $disabled = wfShellExecDisabled();
2664         if ( $disabled ) {
2665                 $retval = 1;
2666                 return $disabled == 'safemode' ?
2667                         'Unable to run external programs in safe mode.' :
2668                         'Unable to run external programs, proc_open() is disabled.';
2669         }
2670
2671         $includeStderr = isset( $options['duplicateStderr'] ) && $options['duplicateStderr'];
2672
2673         wfInitShellLocale();
2674
2675         $envcmd = '';
2676         foreach ( $environ as $k => $v ) {
2677                 if ( wfIsWindows() ) {
2678                         /* Surrounding a set in quotes (method used by wfEscapeShellArg) makes the quotes themselves
2679                          * appear in the environment variable, so we must use carat escaping as documented in
2680                          * http://technet.microsoft.com/en-us/library/cc723564.aspx
2681                          * Note however that the quote isn't listed there, but is needed, and the parentheses
2682                          * are listed there but doesn't appear to need it.
2683                          */
2684                         $envcmd .= "set $k=" . preg_replace( '/([&|()<>^"])/', '^\\1', $v ) . '&& ';
2685                 } else {
2686                         /* Assume this is a POSIX shell, thus required to accept variable assignments before the command
2687                          * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_01
2688                          */
2689                         $envcmd .= "$k=" . escapeshellarg( $v ) . ' ';
2690                 }
2691         }
2692         if ( is_array( $cmd ) ) {
2693                 // Command line may be given as an array, escape each value and glue them together with a space
2694                 $cmdVals = array();
2695                 foreach ( $cmd as $val ) {
2696                         $cmdVals[] = wfEscapeShellArg( $val );
2697                 }
2698                 $cmd = implode( ' ', $cmdVals );
2699         }
2700
2701         $cmd = $envcmd . $cmd;
2702
2703         $useLogPipe = false;
2704         if ( is_executable( '/bin/bash' ) ) {
2705                 $time = intval ( isset( $limits['time'] ) ? $limits['time'] : $wgMaxShellTime );
2706                 if ( isset( $limits['walltime'] ) ) {
2707                         $wallTime = intval( $limits['walltime'] );
2708                 } elseif ( isset( $limits['time'] ) ) {
2709                         $wallTime = $time;
2710                 } else {
2711                         $wallTime = intval( $wgMaxShellWallClockTime );
2712                 }
2713                 $mem = intval ( isset( $limits['memory'] ) ? $limits['memory'] : $wgMaxShellMemory );
2714                 $filesize = intval ( isset( $limits['filesize'] ) ? $limits['filesize'] : $wgMaxShellFileSize );
2715
2716                 if ( $time > 0 || $mem > 0 || $filesize > 0 || $wallTime > 0 ) {
2717                         $cmd = '/bin/bash ' . escapeshellarg( "$IP/includes/limit.sh" ) . ' ' .
2718                                 escapeshellarg( $cmd ) . ' ' .
2719                                 escapeshellarg(
2720                                         "MW_INCLUDE_STDERR=" . ( $includeStderr ? '1' : '' ) . ';' .
2721                                         "MW_CPU_LIMIT=$time; " .
2722                                         'MW_CGROUP=' . escapeshellarg( $wgShellCgroup ) . '; ' .
2723                                         "MW_MEM_LIMIT=$mem; " .
2724                                         "MW_FILE_SIZE_LIMIT=$filesize; " .
2725                                         "MW_WALL_CLOCK_LIMIT=$wallTime; " .
2726                                         "MW_USE_LOG_PIPE=yes"
2727                                 );
2728                         $useLogPipe = true;
2729                 } elseif ( $includeStderr ) {
2730                         $cmd .= ' 2>&1';
2731                 }
2732         } elseif ( $includeStderr ) {
2733                 $cmd .= ' 2>&1';
2734         }
2735         wfDebug( "wfShellExec: $cmd\n" );
2736
2737         $desc = array(
2738                 0 => array( 'file', 'php://stdin', 'r' ),
2739                 1 => array( 'pipe', 'w' ),
2740                 2 => array( 'file', 'php://stderr', 'w' ) );
2741         if ( $useLogPipe ) {
2742                 $desc[3] = array( 'pipe', 'w' );
2743         }
2744         $pipes = null;
2745         $proc = proc_open( $cmd, $desc, $pipes );
2746         if ( !$proc ) {
2747                 wfDebugLog( 'exec', "proc_open() failed: $cmd" );
2748                 $retval = -1;
2749                 return '';
2750         }
2751         $outBuffer = $logBuffer = '';
2752         $emptyArray = array();
2753         $status = false;
2754         $logMsg = false;
2755
2756         // According to the documentation, it is possible for stream_select()
2757         // to fail due to EINTR. I haven't managed to induce this in testing
2758         // despite sending various signals. If it did happen, the error
2759         // message would take the form:
2760         //
2761         // stream_select(): unable to select [4]: Interrupted system call (max_fd=5)
2762         //
2763         // where [4] is the value of the macro EINTR and "Interrupted system
2764         // call" is string which according to the Linux manual is "possibly"
2765         // localised according to LC_MESSAGES.
2766         $eintr = defined( 'SOCKET_EINTR' ) ? SOCKET_EINTR : 4;
2767         $eintrMessage = "stream_select(): unable to select [$eintr]";
2768
2769         // Build a table mapping resource IDs to pipe FDs to work around a
2770         // PHP 5.3 issue in which stream_select() does not preserve array keys
2771         // <https://bugs.php.net/bug.php?id=53427>.
2772         $fds = array();
2773         foreach ( $pipes as $fd => $pipe ) {
2774                 $fds[(int)$pipe] = $fd;
2775         }
2776
2777         $running = true;
2778         $timeout = null;
2779         $numReadyPipes = 0;
2780
2781         while ( $running === true || $numReadyPipes !== 0 ) {
2782                 if ( $running ) {
2783                         $status = proc_get_status( $proc );
2784                         // If the process has terminated, switch to nonblocking selects
2785                         // for getting any data still waiting to be read.
2786                         if ( !$status['running'] ) {
2787                                 $running = false;
2788                                 $timeout = 0;
2789                         }
2790                 }
2791
2792                 $readyPipes = $pipes;
2793
2794                 // Clear last error
2795                 // @codingStandardsIgnoreStart Generic.PHP.NoSilencedErrors.Discouraged
2796                 @trigger_error( '' );
2797                 $numReadyPipes = @stream_select( $readyPipes, $emptyArray, $emptyArray, $timeout );
2798                 if ( $numReadyPipes === false ) {
2799                         // @codingStandardsIgnoreEnd
2800                         $error = error_get_last();
2801                         if ( strncmp( $error['message'], $eintrMessage, strlen( $eintrMessage ) ) == 0 ) {
2802                                 continue;
2803                         } else {
2804                                 trigger_error( $error['message'], E_USER_WARNING );
2805                                 $logMsg = $error['message'];
2806                                 break;
2807                         }
2808                 }
2809                 foreach ( $readyPipes as $pipe ) {
2810                         $block = fread( $pipe, 65536 );
2811                         $fd = $fds[(int)$pipe];
2812                         if ( $block === '' ) {
2813                                 // End of file
2814                                 fclose( $pipes[$fd] );
2815                                 unset( $pipes[$fd] );
2816                                 if ( !$pipes ) {
2817                                         break 2;
2818                                 }
2819                         } elseif ( $block === false ) {
2820                                 // Read error
2821                                 $logMsg = "Error reading from pipe";
2822                                 break 2;
2823                         } elseif ( $fd == 1 ) {
2824                                 // From stdout
2825                                 $outBuffer .= $block;
2826                         } elseif ( $fd == 3 ) {
2827                                 // From log FD
2828                                 $logBuffer .= $block;
2829                                 if ( strpos( $block, "\n" ) !== false ) {
2830                                         $lines = explode( "\n", $logBuffer );
2831                                         $logBuffer = array_pop( $lines );
2832                                         foreach ( $lines as $line ) {
2833                                                 wfDebugLog( 'exec', $line );
2834                                         }
2835                                 }
2836                         }
2837                 }
2838         }
2839
2840         foreach ( $pipes as $pipe ) {
2841                 fclose( $pipe );
2842         }
2843
2844         // Use the status previously collected if possible, since proc_get_status()
2845         // just calls waitpid() which will not return anything useful the second time.
2846         if ( $running ) {
2847                 $status = proc_get_status( $proc );
2848         }
2849
2850         if ( $logMsg !== false ) {
2851                 // Read/select error
2852                 $retval = -1;
2853                 proc_close( $proc );
2854         } elseif ( $status['signaled'] ) {
2855                 $logMsg = "Exited with signal {$status['termsig']}";
2856                 $retval = 128 + $status['termsig'];
2857                 proc_close( $proc );
2858         } else {
2859                 if ( $status['running'] ) {
2860                         $retval = proc_close( $proc );
2861                 } else {
2862                         $retval = $status['exitcode'];
2863                         proc_close( $proc );
2864                 }
2865                 if ( $retval == 127 ) {
2866                         $logMsg = "Possibly missing executable file";
2867                 } elseif ( $retval >= 129 && $retval <= 192 ) {
2868                         $logMsg = "Probably exited with signal " . ( $retval - 128 );
2869                 }
2870         }
2871
2872         if ( $logMsg !== false ) {
2873                 wfDebugLog( 'exec', "$logMsg: $cmd" );
2874         }
2875
2876         return $outBuffer;
2877 }
2878
2879 /**
2880  * Execute a shell command, returning both stdout and stderr. Convenience
2881  * function, as all the arguments to wfShellExec can become unwieldy.
2882  *
2883  * @note This also includes errors from limit.sh, e.g. if $wgMaxShellFileSize is exceeded.
2884  * @param string|string[] $cmd If string, a properly shell-escaped command line,
2885  *   or an array of unescaped arguments, in which case each value will be escaped
2886  *   Example:   [ 'convert', '-font', 'font name' ] would produce "'convert' '-font' 'font name'"
2887  * @param null|mixed &$retval Optional, will receive the program's exit code.
2888  *   (non-zero is usually failure)
2889  * @param array $environ Optional environment variables which should be
2890  *   added to the executed command environment.
2891  * @param array $limits Optional array with limits(filesize, memory, time, walltime)
2892  *   this overwrites the global wgMaxShell* limits.
2893  * @return string Collected stdout and stderr as a string
2894  */
2895 function wfShellExecWithStderr( $cmd, &$retval = null, $environ = array(), $limits = array() ) {
2896         return wfShellExec( $cmd, $retval, $environ, $limits, array( 'duplicateStderr' => true ) );
2897 }
2898
2899 /**
2900  * Workaround for http://bugs.php.net/bug.php?id=45132
2901  * escapeshellarg() destroys non-ASCII characters if LANG is not a UTF-8 locale
2902  */
2903 function wfInitShellLocale() {
2904         static $done = false;
2905         if ( $done ) {
2906                 return;
2907         }
2908         $done = true;
2909         global $wgShellLocale;
2910         if ( !wfIniGetBool( 'safe_mode' ) ) {
2911                 putenv( "LC_CTYPE=$wgShellLocale" );
2912                 setlocale( LC_CTYPE, $wgShellLocale );
2913         }
2914 }
2915
2916 /**
2917  * Alias to wfShellWikiCmd()
2918  *
2919  * @see wfShellWikiCmd()
2920  */
2921 function wfShellMaintenanceCmd( $script, array $parameters = array(), array $options = array() ) {
2922         return wfShellWikiCmd( $script, $parameters, $options );
2923 }
2924
2925 /**
2926  * Generate a shell-escaped command line string to run a MediaWiki cli script.
2927  * Note that $parameters should be a flat array and an option with an argument
2928  * should consist of two consecutive items in the array (do not use "--option value").
2929  *
2930  * @param string $script MediaWiki cli script path
2931  * @param array $parameters Arguments and options to the script
2932  * @param array $options Associative array of options:
2933  *              'php': The path to the php executable
2934  *              'wrapper': Path to a PHP wrapper to handle the maintenance script
2935  * @return string
2936  */
2937 function wfShellWikiCmd( $script, array $parameters = array(), array $options = array() ) {
2938         global $wgPhpCli;
2939         // Give site config file a chance to run the script in a wrapper.
2940         // The caller may likely want to call wfBasename() on $script.
2941         wfRunHooks( 'wfShellWikiCmd', array( &$script, &$parameters, &$options ) );
2942         $cmd = isset( $options['php'] ) ? array( $options['php'] ) : array( $wgPhpCli );
2943         if ( isset( $options['wrapper'] ) ) {
2944                 $cmd[] = $options['wrapper'];
2945         }
2946         $cmd[] = $script;
2947         // Escape each parameter for shell
2948         return implode( " ", array_map( 'wfEscapeShellArg', array_merge( $cmd, $parameters ) ) );
2949 }
2950
2951 /**
2952  * wfMerge attempts to merge differences between three texts.
2953  * Returns true for a clean merge and false for failure or a conflict.
2954  *
2955  * @param string $old
2956  * @param string $mine
2957  * @param string $yours
2958  * @param string $result
2959  * @return bool
2960  */
2961 function wfMerge( $old, $mine, $yours, &$result ) {
2962         global $wgDiff3;
2963
2964         # This check may also protect against code injection in
2965         # case of broken installations.
2966         wfSuppressWarnings();
2967         $haveDiff3 = $wgDiff3 && file_exists( $wgDiff3 );
2968         wfRestoreWarnings();
2969
2970         if ( !$haveDiff3 ) {
2971                 wfDebug( "diff3 not found\n" );
2972                 return false;
2973         }
2974
2975         # Make temporary files
2976         $td = wfTempDir();
2977         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
2978         $mytextFile = fopen( $mytextName = tempnam( $td, 'merge-mine-' ), 'w' );
2979         $yourtextFile = fopen( $yourtextName = tempnam( $td, 'merge-your-' ), 'w' );
2980
2981         # NOTE: diff3 issues a warning to stderr if any of the files does not end with
2982         #       a newline character. To avoid this, we normalize the trailing whitespace before
2983         #       creating the diff.
2984
2985         fwrite( $oldtextFile, rtrim( $old ) . "\n" );
2986         fclose( $oldtextFile );
2987         fwrite( $mytextFile, rtrim( $mine ) . "\n" );
2988         fclose( $mytextFile );
2989         fwrite( $yourtextFile, rtrim( $yours ) . "\n" );
2990         fclose( $yourtextFile );
2991
2992         # Check for a conflict
2993         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a --overlap-only ' .
2994                 wfEscapeShellArg( $mytextName ) . ' ' .
2995                 wfEscapeShellArg( $oldtextName ) . ' ' .
2996                 wfEscapeShellArg( $yourtextName );
2997         $handle = popen( $cmd, 'r' );
2998
2999         if ( fgets( $handle, 1024 ) ) {
3000                 $conflict = true;
3001         } else {
3002                 $conflict = false;
3003         }
3004         pclose( $handle );
3005
3006         # Merge differences
3007         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a -e --merge ' .
3008                 wfEscapeShellArg( $mytextName, $oldtextName, $yourtextName );
3009         $handle = popen( $cmd, 'r' );
3010         $result = '';
3011         do {
3012                 $data = fread( $handle, 8192 );
3013                 if ( strlen( $data ) == 0 ) {
3014                         break;
3015                 }
3016                 $result .= $data;
3017         } while ( true );
3018         pclose( $handle );
3019         unlink( $mytextName );
3020         unlink( $oldtextName );
3021         unlink( $yourtextName );
3022
3023         if ( $result === '' && $old !== '' && !$conflict ) {
3024                 wfDebug( "Unexpected null result from diff3. Command: $cmd\n" );
3025                 $conflict = true;
3026         }
3027         return !$conflict;
3028 }
3029
3030 /**
3031  * Returns unified plain-text diff of two texts.
3032  * Useful for machine processing of diffs.
3033  *
3034  * @param string $before The text before the changes.
3035  * @param string $after The text after the changes.
3036  * @param string $params Command-line options for the diff command.
3037  * @return string Unified diff of $before and $after
3038  */
3039 function wfDiff( $before, $after, $params = '-u' ) {
3040         if ( $before == $after ) {
3041                 return '';
3042         }
3043
3044         global $wgDiff;
3045         wfSuppressWarnings();
3046         $haveDiff = $wgDiff && file_exists( $wgDiff );
3047         wfRestoreWarnings();
3048
3049         # This check may also protect against code injection in
3050         # case of broken installations.
3051         if ( !$haveDiff ) {
3052                 wfDebug( "diff executable not found\n" );
3053                 $diffs = new Diff( explode( "\n", $before ), explode( "\n", $after ) );
3054                 $format = new UnifiedDiffFormatter();
3055                 return $format->format( $diffs );
3056         }
3057
3058         # Make temporary files
3059         $td = wfTempDir();
3060         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
3061         $newtextFile = fopen( $newtextName = tempnam( $td, 'merge-your-' ), 'w' );
3062
3063         fwrite( $oldtextFile, $before );
3064         fclose( $oldtextFile );
3065         fwrite( $newtextFile, $after );
3066         fclose( $newtextFile );
3067
3068         // Get the diff of the two files
3069         $cmd = "$wgDiff " . $params . ' ' . wfEscapeShellArg( $oldtextName, $newtextName );
3070
3071         $h = popen( $cmd, 'r' );
3072
3073         $diff = '';
3074
3075         do {
3076                 $data = fread( $h, 8192 );
3077                 if ( strlen( $data ) == 0 ) {
3078                         break;
3079                 }
3080                 $diff .= $data;
3081         } while ( true );
3082
3083         // Clean up
3084         pclose( $h );
3085         unlink( $oldtextName );
3086         unlink( $newtextName );
3087
3088         // Kill the --- and +++ lines. They're not useful.
3089         $diff_lines = explode( "\n", $diff );
3090         if ( isset( $diff_lines[0] ) && strpos( $diff_lines[0], '---' ) === 0 ) {
3091                 unset( $diff_lines[0] );
3092         }
3093         if ( isset( $diff_lines[1] ) && strpos( $diff_lines[1], '+++' ) === 0 ) {
3094                 unset( $diff_lines[1] );
3095         }
3096
3097         $diff = implode( "\n", $diff_lines );
3098
3099         return $diff;
3100 }
3101
3102 /**
3103  * This function works like "use VERSION" in Perl, the program will die with a
3104  * backtrace if the current version of PHP is less than the version provided
3105  *
3106  * This is useful for extensions which due to their nature are not kept in sync
3107  * with releases, and might depend on other versions of PHP than the main code
3108  *
3109  * Note: PHP might die due to parsing errors in some cases before it ever
3110  *       manages to call this function, such is life
3111  *
3112  * @see perldoc -f use
3113  *
3114  * @param string|int|float $req_ver The version to check, can be a string, an integer, or a float
3115  * @throws MWException
3116  */
3117 function wfUsePHP( $req_ver ) {
3118         $php_ver = PHP_VERSION;
3119
3120         if ( version_compare( $php_ver, (string)$req_ver, '<' ) ) {
3121                 throw new MWException( "PHP $req_ver required--this is only $php_ver" );
3122         }
3123 }
3124
3125 /**
3126  * This function works like "use VERSION" in Perl except it checks the version
3127  * of MediaWiki, the program will die with a backtrace if the current version
3128  * of MediaWiki is less than the version provided.
3129  *
3130  * This is useful for extensions which due to their nature are not kept in sync
3131  * with releases
3132  *
3133  * Note: Due to the behavior of PHP's version_compare() which is used in this
3134  * function, if you want to allow the 'wmf' development versions add a 'c' (or
3135  * any single letter other than 'a', 'b' or 'p') as a post-fix to your
3136  * targeted version number. For example if you wanted to allow any variation
3137  * of 1.22 use `wfUseMW( '1.22c' )`. Using an 'a' or 'b' instead of 'c' will
3138  * not result in the same comparison due to the internal logic of
3139  * version_compare().
3140  *
3141  * @see perldoc -f use
3142  *
3143  * @param string|int|float $req_ver The version to check, can be a string, an integer, or a float
3144  * @throws MWException
3145  */
3146 function wfUseMW( $req_ver ) {
3147         global $wgVersion;
3148
3149         if ( version_compare( $wgVersion, (string)$req_ver, '<' ) ) {
3150                 throw new MWException( "MediaWiki $req_ver required--this is only $wgVersion" );
3151         }
3152 }
3153
3154 /**
3155  * Return the final portion of a pathname.
3156  * Reimplemented because PHP5's "basename()" is buggy with multibyte text.
3157  * http://bugs.php.net/bug.php?id=33898
3158  *
3159  * PHP's basename() only considers '\' a pathchar on Windows and Netware.
3160  * We'll consider it so always, as we don't want '\s' in our Unix paths either.
3161  *
3162  * @param string $path
3163  * @param string $suffix String to remove if present
3164  * @return string
3165  */
3166 function wfBaseName( $path, $suffix = '' ) {
3167         if ( $suffix == '' ) {
3168                 $encSuffix = '';
3169         } else {
3170                 $encSuffix = '(?:' . preg_quote( $suffix, '#' ) . ')?';
3171         }
3172
3173         $matches = array();
3174         if ( preg_match( "#([^/\\\\]*?){$encSuffix}[/\\\\]*$#", $path, $matches ) ) {
3175                 return $matches[1];
3176         } else {
3177                 return '';
3178         }
3179 }
3180
3181 /**
3182  * Generate a relative path name to the given file.
3183  * May explode on non-matching case-insensitive paths,
3184  * funky symlinks, etc.
3185  *
3186  * @param string $path Absolute destination path including target filename
3187  * @param string $from Absolute source path, directory only
3188  * @return string
3189  */
3190 function wfRelativePath( $path, $from ) {
3191         // Normalize mixed input on Windows...
3192         $path = str_replace( '/', DIRECTORY_SEPARATOR, $path );
3193         $from = str_replace( '/', DIRECTORY_SEPARATOR, $from );
3194
3195         // Trim trailing slashes -- fix for drive root
3196         $path = rtrim( $path, DIRECTORY_SEPARATOR );
3197         $from = rtrim( $from, DIRECTORY_SEPARATOR );
3198
3199         $pieces = explode( DIRECTORY_SEPARATOR, dirname( $path ) );
3200         $against = explode( DIRECTORY_SEPARATOR, $from );
3201
3202         if ( $pieces[0] !== $against[0] ) {
3203                 // Non-matching Windows drive letters?
3204                 // Return a full path.
3205                 return $path;
3206         }
3207
3208         // Trim off common prefix
3209         while ( count( $pieces ) && count( $against )
3210                 && $pieces[0] == $against[0] ) {
3211                 array_shift( $pieces );
3212                 array_shift( $against );
3213         }
3214
3215         // relative dots to bump us to the parent
3216         while ( count( $against ) ) {
3217                 array_unshift( $pieces, '..' );
3218                 array_shift( $against );
3219         }
3220
3221         array_push( $pieces, wfBaseName( $path ) );
3222
3223         return implode( DIRECTORY_SEPARATOR, $pieces );
3224 }
3225
3226 /**
3227  * Convert an arbitrarily-long digit string from one numeric base
3228  * to another, optionally zero-padding to a minimum column width.
3229  *
3230  * Supports base 2 through 36; digit values 10-36 are represented
3231  * as lowercase letters a-z. Input is case-insensitive.
3232  *
3233  * @param string $input Input number
3234  * @param int $sourceBase Base of the input number
3235  * @param int $destBase Desired base of the output
3236  * @param int $pad Minimum number of digits in the output (pad with zeroes)
3237  * @param bool $lowercase Whether to output in lowercase or uppercase
3238  * @param string $engine Either "gmp", "bcmath", or "php"
3239  * @return string|bool The output number as a string, or false on error
3240  */
3241 function wfBaseConvert( $input, $sourceBase, $destBase, $pad = 1,
3242         $lowercase = true, $engine = 'auto'
3243 ) {
3244         $input = (string)$input;
3245         if (
3246                 $sourceBase < 2 ||
3247                 $sourceBase > 36 ||
3248                 $destBase < 2 ||
3249                 $destBase > 36 ||
3250                 $sourceBase != (int)$sourceBase ||
3251                 $destBase != (int)$destBase ||
3252                 $pad != (int)$pad ||
3253                 !preg_match(
3254                         "/^[" . substr( '0123456789abcdefghijklmnopqrstuvwxyz', 0, $sourceBase ) . "]+$/i",
3255                         $input
3256                 )
3257         ) {
3258                 return false;
3259         }
3260
3261         static $baseChars = array(
3262                 10 => 'a', 11 => 'b', 12 => 'c', 13 => 'd', 14 => 'e', 15 => 'f',
3263                 16 => 'g', 17 => 'h', 18 => 'i', 19 => 'j', 20 => 'k', 21 => 'l',
3264                 22 => 'm', 23 => 'n', 24 => 'o', 25 => 'p', 26 => 'q', 27 => 'r',
3265                 28 => 's', 29 => 't', 30 => 'u', 31 => 'v', 32 => 'w', 33 => 'x',
3266                 34 => 'y', 35 => 'z',
3267
3268                 '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5,
3269                 '6' => 6, '7' => 7, '8' => 8, '9' => 9, 'a' => 10, 'b' => 11,
3270                 'c' => 12, 'd' => 13, 'e' => 14, 'f' => 15, 'g' => 16, 'h' => 17,
3271                 'i' => 18, 'j' => 19, 'k' => 20, 'l' => 21, 'm' => 22, 'n' => 23,
3272                 'o' => 24, 'p' => 25, 'q' => 26, 'r' => 27, 's' => 28, 't' => 29,
3273                 'u' => 30, 'v' => 31, 'w' => 32, 'x' => 33, 'y' => 34, 'z' => 35
3274         );
3275
3276         if ( extension_loaded( 'gmp' ) && ( $engine == 'auto' || $engine == 'gmp' ) ) {
3277                 // Removing leading zeros works around broken base detection code in
3278                 // some PHP versions (see <https://bugs.php.net/bug.php?id=50175> and
3279                 // <https://bugs.php.net/bug.php?id=55398>).
3280                 $result = gmp_strval( gmp_init( ltrim( $input, '0' ), $sourceBase ), $destBase );
3281         } elseif ( extension_loaded( 'bcmath' ) && ( $engine == 'auto' || $engine == 'bcmath' ) ) {
3282                 $decimal = '0';
3283                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3284                         $decimal = bcmul( $decimal, $sourceBase );
3285                         $decimal = bcadd( $decimal, $baseChars[$char] );
3286                 }
3287
3288                 // @codingStandardsIgnoreStart Generic.CodeAnalysis.ForLoopWithTestFunctionCall.NotAllowed
3289                 for ( $result = ''; bccomp( $decimal, 0 ); $decimal = bcdiv( $decimal, $destBase, 0 ) ) {
3290                         $result .= $baseChars[bcmod( $decimal, $destBase )];
3291                 }
3292                 // @codingStandardsIgnoreEnd
3293
3294                 $result = strrev( $result );
3295         } else {
3296                 $inDigits = array();
3297                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3298                         $inDigits[] = $baseChars[$char];
3299                 }
3300
3301                 // Iterate over the input, modulo-ing out an output digit
3302                 // at a time until input is gone.
3303                 $result = '';
3304                 while ( $inDigits ) {
3305                         $work = 0;
3306                         $workDigits = array();
3307
3308                         // Long division...
3309                         foreach ( $inDigits as $digit ) {
3310                                 $work *= $sourceBase;
3311                                 $work += $digit;
3312
3313                                 if ( $workDigits || $work >= $destBase ) {
3314                                         $workDigits[] = (int)( $work / $destBase );
3315                                 }
3316                                 $work %= $destBase;
3317                         }
3318
3319                         // All that division leaves us with a remainder,
3320                         // which is conveniently our next output digit.
3321                         $result .= $baseChars[$work];
3322
3323                         // And we continue!
3324                         $inDigits = $workDigits;
3325                 }
3326
3327                 $result = strrev( $result );
3328         }
3329
3330         if ( !$lowercase ) {
3331                 $result = strtoupper( $result );
3332         }
3333
3334         return str_pad( $result, $pad, '0', STR_PAD_LEFT );
3335 }
3336
3337 /**
3338  * Check if there is sufficient entropy in php's built-in session generation
3339  *
3340  * @return bool True = there is sufficient entropy
3341  */
3342 function wfCheckEntropy() {
3343         return (
3344                         ( wfIsWindows() && version_compare( PHP_VERSION, '5.3.3', '>=' ) )
3345                         || ini_get( 'session.entropy_file' )
3346                 )
3347                 && intval( ini_get( 'session.entropy_length' ) ) >= 32;
3348 }
3349
3350 /**
3351  * Override session_id before session startup if php's built-in
3352  * session generation code is not secure.
3353  */
3354 function wfFixSessionID() {
3355         // If the cookie or session id is already set we already have a session and should abort
3356         if ( isset( $_COOKIE[session_name()] ) || session_id() ) {
3357                 return;
3358         }
3359
3360         // PHP's built-in session entropy is enabled if:
3361         // - entropy_file is set or you're on Windows with php 5.3.3+
3362         // - AND entropy_length is > 0
3363         // We treat it as disabled if it doesn't have an entropy length of at least 32
3364         $entropyEnabled = wfCheckEntropy();
3365
3366         // If built-in entropy is not enabled or not sufficient override PHP's
3367         // built in session id generation code
3368         if ( !$entropyEnabled ) {
3369                 wfDebug( __METHOD__ . ": PHP's built in entropy is disabled or not sufficient, " .
3370                         "overriding session id generation using our cryptrand source.\n" );
3371                 session_id( MWCryptRand::generateHex( 32 ) );
3372         }
3373 }
3374
3375 /**
3376  * Reset the session_id
3377  *
3378  * @since 1.22
3379  */
3380 function wfResetSessionID() {
3381         global $wgCookieSecure;
3382         $oldSessionId = session_id();
3383         $cookieParams = session_get_cookie_params();
3384         if ( wfCheckEntropy() && $wgCookieSecure == $cookieParams['secure'] ) {
3385                 session_regenerate_id( false );
3386         } else {
3387                 $tmp = $_SESSION;
3388                 session_destroy();
3389                 wfSetupSession( MWCryptRand::generateHex( 32 ) );
3390                 $_SESSION = $tmp;
3391         }
3392         $newSessionId = session_id();
3393         wfRunHooks( 'ResetSessionID', array( $oldSessionId, $newSessionId ) );
3394 }
3395
3396 /**
3397  * Initialise php session
3398  *
3399  * @param bool $sessionId
3400  */
3401 function wfSetupSession( $sessionId = false ) {
3402         global $wgSessionsInMemcached, $wgSessionsInObjectCache, $wgCookiePath, $wgCookieDomain,
3403                         $wgCookieSecure, $wgCookieHttpOnly, $wgSessionHandler;
3404         if ( $wgSessionsInObjectCache || $wgSessionsInMemcached ) {
3405                 ObjectCacheSessionHandler::install();
3406         } elseif ( $wgSessionHandler && $wgSessionHandler != ini_get( 'session.save_handler' ) ) {
3407                 # Only set this if $wgSessionHandler isn't null and session.save_handler
3408                 # hasn't already been set to the desired value (that causes errors)
3409                 ini_set( 'session.save_handler', $wgSessionHandler );
3410         }
3411         session_set_cookie_params(
3412                 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $wgCookieHttpOnly );
3413         session_cache_limiter( 'private, must-revalidate' );
3414         if ( $sessionId ) {
3415                 session_id( $sessionId );
3416         } else {
3417                 wfFixSessionID();
3418         }
3419         wfSuppressWarnings();
3420         session_start();
3421         wfRestoreWarnings();
3422 }
3423
3424 /**
3425  * Get an object from the precompiled serialized directory
3426  *
3427  * @param string $name
3428  * @return mixed The variable on success, false on failure
3429  */
3430 function wfGetPrecompiledData( $name ) {
3431         global $IP;
3432
3433         $file = "$IP/serialized/$name";
3434         if ( file_exists( $file ) ) {
3435                 $blob = file_get_contents( $file );
3436                 if ( $blob ) {
3437                         return unserialize( $blob );
3438                 }
3439         }
3440         return false;
3441 }
3442
3443 /**
3444  * Get a cache key
3445  *
3446  * @param string $args,...
3447  * @return string
3448  */
3449 function wfMemcKey( /*...*/ ) {
3450         global $wgCachePrefix;
3451         $prefix = $wgCachePrefix === false ? wfWikiID() : $wgCachePrefix;
3452         $args = func_get_args();
3453         $key = $prefix . ':' . implode( ':', $args );
3454         $key = str_replace( ' ', '_', $key );
3455         return $key;
3456 }
3457
3458 /**
3459  * Get a cache key for a foreign DB
3460  *
3461  * @param string $db
3462  * @param string $prefix
3463  * @param string $args,...
3464  * @return string
3465  */
3466 function wfForeignMemcKey( $db, $prefix /*...*/ ) {
3467         $args = array_slice( func_get_args(), 2 );
3468         if ( $prefix ) {
3469                 $key = "$db-$prefix:" . implode( ':', $args );
3470         } else {
3471                 $key = $db . ':' . implode( ':', $args );
3472         }
3473         return str_replace( ' ', '_', $key );
3474 }
3475
3476 /**
3477  * Get an ASCII string identifying this wiki
3478  * This is used as a prefix in memcached keys
3479  *
3480  * @return string
3481  */
3482 function wfWikiID() {
3483         global $wgDBprefix, $wgDBname;
3484         if ( $wgDBprefix ) {
3485                 return "$wgDBname-$wgDBprefix";
3486         } else {
3487                 return $wgDBname;
3488         }
3489 }
3490
3491 /**
3492  * Split a wiki ID into DB name and table prefix
3493  *
3494  * @param string $wiki
3495  *
3496  * @return array
3497  */
3498 function wfSplitWikiID( $wiki ) {
3499         $bits = explode( '-', $wiki, 2 );
3500         if ( count( $bits ) < 2 ) {
3501                 $bits[] = '';
3502         }
3503         return $bits;
3504 }
3505
3506 /**
3507  * Get a Database object.
3508  *
3509  * @param int $db Index of the connection to get. May be DB_MASTER for the
3510  *            master (for write queries), DB_SLAVE for potentially lagged read
3511  *            queries, or an integer >= 0 for a particular server.
3512  *
3513  * @param string|string[] $groups Query groups. An array of group names that this query
3514  *                belongs to. May contain a single string if the query is only
3515  *                in one group.
3516  *
3517  * @param string|bool $wiki The wiki ID, or false for the current wiki
3518  *
3519  * Note: multiple calls to wfGetDB(DB_SLAVE) during the course of one request
3520  * will always return the same object, unless the underlying connection or load
3521  * balancer is manually destroyed.
3522  *
3523  * Note 2: use $this->getDB() in maintenance scripts that may be invoked by
3524  * updater to ensure that a proper database is being updated.
3525  *
3526  * @return DatabaseBase
3527  */
3528 function &wfGetDB( $db, $groups = array(), $wiki = false ) {
3529         return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
3530 }
3531
3532 /**
3533  * Get a load balancer object.
3534  *
3535  * @param string|bool $wiki Wiki ID, or false for the current wiki
3536  * @return LoadBalancer
3537  */
3538 function wfGetLB( $wiki = false ) {
3539         return wfGetLBFactory()->getMainLB( $wiki );
3540 }
3541
3542 /**
3543  * Get the load balancer factory object
3544  *
3545  * @return LBFactory
3546  */
3547 function &wfGetLBFactory() {
3548         return LBFactory::singleton();
3549 }
3550
3551 /**
3552  * Find a file.
3553  * Shortcut for RepoGroup::singleton()->findFile()
3554  *
3555  * @param string $title String or Title object
3556  * @param array $options Associative array of options:
3557  *     time:           requested time for an archived image, or false for the
3558  *                     current version. An image object will be returned which was
3559  *                     created at the specified time.
3560  *
3561  *     ignoreRedirect: If true, do not follow file redirects
3562  *
3563  *     private:        If true, return restricted (deleted) files if the current
3564  *                     user is allowed to view them. Otherwise, such files will not
3565  *                     be found.
3566  *
3567  *     bypassCache:    If true, do not use the process-local cache of File objects
3568  *
3569  * @return File|bool File, or false if the file does not exist
3570  */
3571 function wfFindFile( $title, $options = array() ) {
3572         return RepoGroup::singleton()->findFile( $title, $options );
3573 }
3574
3575 /**
3576  * Get an object referring to a locally registered file.
3577  * Returns a valid placeholder object if the file does not exist.
3578  *
3579  * @param Title|string $title
3580  * @return LocalFile|null A File, or null if passed an invalid Title
3581  */
3582 function wfLocalFile( $title ) {
3583         return RepoGroup::singleton()->getLocalRepo()->newFile( $title );
3584 }
3585
3586 /**
3587  * Should low-performance queries be disabled?
3588  *
3589  * @return bool
3590  * @codeCoverageIgnore
3591  */
3592 function wfQueriesMustScale() {
3593         global $wgMiserMode;
3594         return $wgMiserMode
3595                 || ( SiteStats::pages() > 100000
3596                 && SiteStats::edits() > 1000000
3597                 && SiteStats::users() > 10000 );
3598 }
3599
3600 /**
3601  * Get the path to a specified script file, respecting file
3602  * extensions; this is a wrapper around $wgScriptExtension etc.
3603  * except for 'index' and 'load' which use $wgScript/$wgLoadScript
3604  *
3605  * @param string $script Script filename, sans extension
3606  * @return string
3607  */
3608 function wfScript( $script = 'index' ) {
3609         global $wgScriptPath, $wgScriptExtension, $wgScript, $wgLoadScript;
3610         if ( $script === 'index' ) {
3611                 return $wgScript;
3612         } elseif ( $script === 'load' ) {
3613                 return $wgLoadScript;
3614         } else {
3615                 return "{$wgScriptPath}/{$script}{$wgScriptExtension}";
3616         }
3617 }
3618
3619 /**
3620  * Get the script URL.
3621  *
3622  * @return string Script URL
3623  */
3624 function wfGetScriptUrl() {
3625         if ( isset( $_SERVER['SCRIPT_NAME'] ) ) {
3626                 #
3627                 # as it was called, minus the query string.
3628                 #
3629                 # Some sites use Apache rewrite rules to handle subdomains,
3630                 # and have PHP set up in a weird way that causes PHP_SELF
3631                 # to contain the rewritten URL instead of the one that the
3632                 # outside world sees.
3633                 #
3634                 # If in this mode, use SCRIPT_URL instead, which mod_rewrite
3635                 # provides containing the "before" URL.
3636                 return $_SERVER['SCRIPT_NAME'];
3637         } else {
3638                 return $_SERVER['URL'];
3639         }
3640 }
3641
3642 /**
3643  * Convenience function converts boolean values into "true"
3644  * or "false" (string) values
3645  *
3646  * @param bool $value
3647  * @return string
3648  */
3649 function wfBoolToStr( $value ) {
3650         return $value ? 'true' : 'false';
3651 }
3652
3653 /**
3654  * Get a platform-independent path to the null file, e.g. /dev/null
3655  *
3656  * @return string
3657  */
3658 function wfGetNull() {
3659         return wfIsWindows() ? 'NUL' : '/dev/null';
3660 }
3661
3662 /**
3663  * Waits for the slaves to catch up to the master position
3664  *
3665  * Use this when updating very large numbers of rows, as in maintenance scripts,
3666  * to avoid causing too much lag. Of course, this is a no-op if there are no slaves.
3667  *
3668  * By default this waits on the main DB cluster of the current wiki.
3669  * If $cluster is set to "*" it will wait on all DB clusters, including
3670  * external ones. If the lag being waiting on is caused by the code that
3671  * does this check, it makes since to use $ifWritesSince, particularly if
3672  * cluster is "*", to avoid excess overhead.
3673  *
3674  * Never call this function after a big DB write that is still in a transaction.
3675  * This only makes sense after the possible lag inducing changes were committed.
3676  *
3677  * @param float|null $ifWritesSince Only wait if writes were done since this UNIX timestamp
3678  * @param string|bool $wiki Wiki identifier accepted by wfGetLB
3679  * @param string|bool $cluster Cluster name accepted by LBFactory. Default: false.
3680  * @param int|null $timeout Max wait time. Default: 1 day (cli), ~10 seconds (web)
3681  * @return bool Success (able to connect and no timeouts reached)
3682  */
3683 function wfWaitForSlaves(
3684         $ifWritesSince = null, $wiki = false, $cluster = false, $timeout = null
3685 ) {
3686         // B/C: first argument used to be "max seconds of lag"; ignore such values
3687         $ifWritesSince = ( $ifWritesSince > 1e9 ) ? $ifWritesSince : null;
3688
3689         if ( $timeout === null ) {
3690                 $timeout = ( PHP_SAPI === 'cli' ) ? 86400 : 10;
3691         }
3692
3693         // Figure out which clusters need to be checked
3694         $lbs = array();
3695         if ( $cluster === '*' ) {
3696                 wfGetLBFactory()->forEachLB( function ( LoadBalancer $lb ) use ( &$lbs ) {
3697                         $lbs[] = $lb;
3698                 } );
3699         } elseif ( $cluster !== false ) {
3700                 $lbs[] = wfGetLBFactory()->getExternalLB( $cluster );
3701         } else {
3702                 $lbs[] = wfGetLB( $wiki );
3703         }
3704
3705         // Get all the master positions of applicable DBs right now.
3706         // This can be faster since waiting on one cluster reduces the
3707         // time needed to wait on the next clusters.
3708         $masterPositions = array_fill( 0, count( $lbs ), false );
3709         foreach ( $lbs as $i => $lb ) {
3710                 // bug 27975 - Don't try to wait for slaves if there are none
3711                 // Prevents permission error when getting master position
3712                 if ( $lb->getServerCount() > 1 ) {
3713                         if ( $ifWritesSince && !$lb->hasMasterConnection() ) {
3714                                 continue; // assume no writes done
3715                         }
3716                         // Use the empty string to not trigger selectDB() since the connection
3717                         // may have been to a server that does not have a DB for the current wiki.
3718                         $dbw = $lb->getConnection( DB_MASTER, array(), '' );
3719                         if ( $ifWritesSince && $dbw->lastDoneWrites() < $ifWritesSince ) {
3720                                 continue; // no writes since the last wait
3721                         }
3722                         $masterPositions[$i] = $dbw->getMasterPos();
3723                 }
3724         }
3725
3726         $ok = true;
3727         foreach ( $lbs as $i => $lb ) {
3728                 if ( $masterPositions[$i] ) {
3729                         // The DBMS may not support getMasterPos() or the whole
3730                         // load balancer might be fake (e.g. $wgAllDBsAreLocalhost).
3731                         $ok = $lb->waitForAll( $masterPositions[$i], $timeout ) && $ok;
3732                 }
3733         }
3734
3735         return $ok;
3736 }
3737
3738 /**
3739  * Count down from $seconds to zero on the terminal, with a one-second pause
3740  * between showing each number. For use in command-line scripts.
3741  *
3742  * @codeCoverageIgnore
3743  * @param int $seconds
3744  */
3745 function wfCountDown( $seconds ) {
3746         for ( $i = $seconds; $i >= 0; $i-- ) {
3747                 if ( $i != $seconds ) {
3748                         echo str_repeat( "\x08", strlen( $i + 1 ) );
3749                 }
3750                 echo $i;
3751                 flush();
3752                 if ( $i ) {
3753                         sleep( 1 );
3754                 }
3755         }
3756         echo "\n";
3757 }
3758
3759 /**
3760  * Replace all invalid characters with -
3761  * Additional characters can be defined in $wgIllegalFileChars (see bug 20489)
3762  * By default, $wgIllegalFileChars = ':'
3763  *
3764  * @param string $name Filename to process
3765  * @return string
3766  */
3767 function wfStripIllegalFilenameChars( $name ) {
3768         global $wgIllegalFileChars;
3769         $illegalFileChars = $wgIllegalFileChars ? "|[" . $wgIllegalFileChars . "]" : '';
3770         $name = wfBaseName( $name );
3771         $name = preg_replace(
3772                 "/[^" . Title::legalChars() . "]" . $illegalFileChars . "/",
3773                 '-',
3774                 $name
3775         );
3776         return $name;
3777 }
3778
3779 /**
3780  * Set PHP's memory limit to the larger of php.ini or $wgMemoryLimit;
3781  *
3782  * @return int Value the memory limit was set to.
3783  */
3784 function wfMemoryLimit() {
3785         global $wgMemoryLimit;
3786         $memlimit = wfShorthandToInteger( ini_get( 'memory_limit' ) );
3787         if ( $memlimit != -1 ) {
3788                 $conflimit = wfShorthandToInteger( $wgMemoryLimit );
3789                 if ( $conflimit == -1 ) {
3790                         wfDebug( "Removing PHP's memory limit\n" );
3791                         wfSuppressWarnings();
3792                         ini_set( 'memory_limit', $conflimit );
3793                         wfRestoreWarnings();
3794                         return $conflimit;
3795                 } elseif ( $conflimit > $memlimit ) {
3796                         wfDebug( "Raising PHP's memory limit to $conflimit bytes\n" );
3797                         wfSuppressWarnings();
3798                         ini_set( 'memory_limit', $conflimit );
3799                         wfRestoreWarnings();
3800                         return $conflimit;
3801                 }
3802         }
3803         return $memlimit;
3804 }
3805
3806 /**
3807  * Converts shorthand byte notation to integer form
3808  *
3809  * @param string $string
3810  * @return int
3811  */
3812 function wfShorthandToInteger( $string = '' ) {
3813         $string = trim( $string );
3814         if ( $string === '' ) {
3815                 return -1;
3816         }
3817         $last = $string[strlen( $string ) - 1];
3818         $val = intval( $string );
3819         switch ( $last ) {
3820                 case 'g':
3821                 case 'G':
3822                         $val *= 1024;
3823                         // break intentionally missing
3824                 case 'm':
3825                 case 'M':
3826                         $val *= 1024;
3827                         // break intentionally missing
3828                 case 'k':
3829                 case 'K':
3830                         $val *= 1024;
3831         }
3832
3833         return $val;
3834 }
3835
3836 /**
3837  * Get the normalised IETF language tag
3838  * See unit test for examples.
3839  *
3840  * @param string $code The language code.
3841  * @return string The language code which complying with BCP 47 standards.
3842  */
3843 function wfBCP47( $code ) {
3844         $codeSegment = explode( '-', $code );
3845         $codeBCP = array();
3846         foreach ( $codeSegment as $segNo => $seg ) {
3847                 // when previous segment is x, it is a private segment and should be lc
3848                 if ( $segNo > 0 && strtolower( $codeSegment[( $segNo - 1 )] ) == 'x' ) {
3849                         $codeBCP[$segNo] = strtolower( $seg );
3850                 // ISO 3166 country code
3851                 } elseif ( ( strlen( $seg ) == 2 ) && ( $segNo > 0 ) ) {
3852                         $codeBCP[$segNo] = strtoupper( $seg );
3853                 // ISO 15924 script code
3854                 } elseif ( ( strlen( $seg ) == 4 ) && ( $segNo > 0 ) ) {
3855                         $codeBCP[$segNo] = ucfirst( strtolower( $seg ) );
3856                 // Use lowercase for other cases
3857                 } else {
3858                         $codeBCP[$segNo] = strtolower( $seg );
3859                 }
3860         }
3861         $langCode = implode( '-', $codeBCP );
3862         return $langCode;
3863 }
3864
3865 /**
3866  * Get a cache object.
3867  *
3868  * @param int $inputType Cache type, one the the CACHE_* constants.
3869  * @return BagOStuff
3870  */
3871 function wfGetCache( $inputType ) {
3872         return ObjectCache::getInstance( $inputType );
3873 }
3874
3875 /**
3876  * Get the main cache object
3877  *
3878  * @return BagOStuff
3879  */
3880 function wfGetMainCache() {
3881         global $wgMainCacheType;
3882         return ObjectCache::getInstance( $wgMainCacheType );
3883 }
3884
3885 /**
3886  * Get the cache object used by the message cache
3887  *
3888  * @return BagOStuff
3889  */
3890 function wfGetMessageCacheStorage() {
3891         global $wgMessageCacheType;
3892         return ObjectCache::getInstance( $wgMessageCacheType );
3893 }
3894
3895 /**
3896  * Get the cache object used by the parser cache
3897  *
3898  * @return BagOStuff
3899  */
3900 function wfGetParserCacheStorage() {
3901         global $wgParserCacheType;
3902         return ObjectCache::getInstance( $wgParserCacheType );
3903 }
3904
3905 /**
3906  * Get the cache object used by the language converter
3907  *
3908  * @return BagOStuff
3909  */
3910 function wfGetLangConverterCacheStorage() {
3911         global $wgLanguageConverterCacheType;
3912         return ObjectCache::getInstance( $wgLanguageConverterCacheType );
3913 }
3914
3915 /**
3916  * Call hook functions defined in $wgHooks
3917  *
3918  * @param string $event Event name
3919  * @param array $args Parameters passed to hook functions
3920  * @param string|null $deprecatedVersion Optionally mark hook as deprecated with version number
3921  *
3922  * @return bool True if no handler aborted the hook
3923  */
3924 function wfRunHooks( $event, array $args = array(), $deprecatedVersion = null ) {
3925         return Hooks::run( $event, $args, $deprecatedVersion );
3926 }
3927
3928 /**
3929  * Wrapper around php's unpack.
3930  *
3931  * @param string $format The format string (See php's docs)
3932  * @param string $data A binary string of binary data
3933  * @param int|bool $length The minimum length of $data or false. This is to
3934  *      prevent reading beyond the end of $data. false to disable the check.
3935  *
3936  * Also be careful when using this function to read unsigned 32 bit integer
3937  * because php might make it negative.
3938  *
3939  * @throws MWException If $data not long enough, or if unpack fails
3940  * @return array Associative array of the extracted data
3941  */
3942 function wfUnpack( $format, $data, $length = false ) {
3943         if ( $length !== false ) {
3944                 $realLen = strlen( $data );
3945                 if ( $realLen < $length ) {
3946                         throw new MWException( "Tried to use wfUnpack on a "
3947                                 . "string of length $realLen, but needed one "
3948                                 . "of at least length $length."
3949                         );
3950                 }
3951         }
3952
3953         wfSuppressWarnings();
3954         $result = unpack( $format, $data );
3955         wfRestoreWarnings();
3956
3957         if ( $result === false ) {
3958                 // If it cannot extract the packed data.
3959                 throw new MWException( "unpack could not unpack binary data" );
3960         }
3961         return $result;
3962 }
3963
3964 /**
3965  * Determine if an image exists on the 'bad image list'.
3966  *
3967  * The format of MediaWiki:Bad_image_list is as follows:
3968  *    * Only list items (lines starting with "*") are considered
3969  *    * The first link on a line must be a link to a bad image
3970  *    * Any subsequent links on the same line are considered to be exceptions,
3971  *      i.e. articles where the image may occur inline.
3972  *
3973  * @param string $name The image name to check
3974  * @param Title|bool $contextTitle The page on which the image occurs, if known
3975  * @param string $blacklist Wikitext of a file blacklist
3976  * @return bool
3977  */
3978 function wfIsBadImage( $name, $contextTitle = false, $blacklist = null ) {
3979         static $badImageCache = null; // based on bad_image_list msg
3980         wfProfileIn( __METHOD__ );
3981
3982         # Handle redirects
3983         $redirectTitle = RepoGroup::singleton()->checkRedirect( Title::makeTitle( NS_FILE, $name ) );
3984         if ( $redirectTitle ) {
3985                 $name = $redirectTitle->getDBkey();
3986         }
3987
3988         # Run the extension hook
3989         $bad = false;
3990         if ( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
3991                 wfProfileOut( __METHOD__ );
3992                 return $bad;
3993         }
3994
3995         $cacheable = ( $blacklist === null );
3996         if ( $cacheable && $badImageCache !== null ) {
3997                 $badImages = $badImageCache;
3998         } else { // cache miss
3999                 if ( $blacklist === null ) {
4000                         $blacklist = wfMessage( 'bad_image_list' )->inContentLanguage()->plain(); // site list
4001                 }
4002                 # Build the list now
4003                 $badImages = array();
4004                 $lines = explode( "\n", $blacklist );
4005                 foreach ( $lines as $line ) {
4006                         # List items only
4007                         if ( substr( $line, 0, 1 ) !== '*' ) {
4008                                 continue;
4009                         }
4010
4011                         # Find all links
4012                         $m = array();
4013                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
4014                                 continue;
4015                         }
4016
4017                         $exceptions = array();
4018                         $imageDBkey = false;
4019                         foreach ( $m[1] as $i => $titleText ) {
4020                                 $title = Title::newFromText( $titleText );
4021                                 if ( !is_null( $title ) ) {
4022                                         if ( $i == 0 ) {
4023                                                 $imageDBkey = $title->getDBkey();
4024                                         } else {
4025                                                 $exceptions[$title->getPrefixedDBkey()] = true;
4026                                         }
4027                                 }
4028                         }
4029
4030                         if ( $imageDBkey !== false ) {
4031                                 $badImages[$imageDBkey] = $exceptions;
4032                         }
4033                 }
4034                 if ( $cacheable ) {
4035                         $badImageCache = $badImages;
4036                 }
4037         }
4038
4039         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
4040         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
4041         wfProfileOut( __METHOD__ );
4042         return $bad;
4043 }
4044
4045 /**
4046  * Determine whether the client at a given source IP is likely to be able to
4047  * access the wiki via HTTPS.
4048  *
4049  * @param string $ip The IPv4/6 address in the normal human-readable form
4050  * @return bool
4051  */
4052 function wfCanIPUseHTTPS( $ip ) {
4053         $canDo = true;
4054         wfRunHooks( 'CanIPUseHTTPS', array( $ip, &$canDo ) );
4055         return !!$canDo;
4056 }
4057
4058 /**
4059  * Work out the IP address based on various globals
4060  * For trusted proxies, use the XFF client IP (first of the chain)
4061  *
4062  * @deprecated since 1.19; call $wgRequest->getIP() directly.
4063  * @return string
4064  */
4065 function wfGetIP() {
4066         wfDeprecated( __METHOD__, '1.19' );
4067         global $wgRequest;
4068         return $wgRequest->getIP();
4069 }
4070
4071 /**
4072  * Checks if an IP is a trusted proxy provider.
4073  * Useful to tell if X-Forwarded-For data is possibly bogus.
4074  * Squid cache servers for the site are whitelisted.
4075  * @deprecated Since 1.24, use IP::isTrustedProxy()
4076  *
4077  * @param string $ip
4078  * @return bool
4079  */
4080 function wfIsTrustedProxy( $ip ) {
4081         return IP::isTrustedProxy( $ip );
4082 }
4083
4084 /**
4085  * Checks if an IP matches a proxy we've configured.
4086  * @deprecated Since 1.24, use IP::isConfiguredProxy()
4087  *
4088  * @param string $ip
4089  * @return bool
4090  * @since 1.23 Supports CIDR ranges in $wgSquidServersNoPurge
4091  */
4092 function wfIsConfiguredProxy( $ip ) {
4093         return IP::isConfiguredProxy( $ip );
4094 }