includes/GlobalFunctions.php

   1 <?php
   2 /**
   3  * Global functions used everywhere.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 if ( !defined( 'MEDIAWIKI' ) ) {
  24         die( "This file is part of MediaWiki, it is not a valid entry point" );
  25 }
  26
  27 // Hide compatibility functions from Doxygen
  28 /// @cond
  29
  30 /**
  31  * Compatibility functions
  32  *
  33  * We support PHP 5.3.2 and up.
  34  * Re-implementations of newer functions or functions in non-standard
  35  * PHP extensions may be included here.
  36  */
  37
  38 if ( !function_exists( 'iconv' ) ) {
  39         /**
  40          * @codeCoverageIgnore
  41          * @return string
  42          */
  43         function iconv( $from, $to, $string ) {
  44                 return Fallback::iconv( $from, $to, $string );
  45         }
  46 }
  47
  48 if ( !function_exists( 'mb_substr' ) ) {
  49         /**
  50          * @codeCoverageIgnore
  51          * @return string
  52          */
  53         function mb_substr( $str, $start, $count = 'end' ) {
  54                 return Fallback::mb_substr( $str, $start, $count );
  55         }
  56
  57         /**
  58          * @codeCoverageIgnore
  59          * @return int
  60          */
  61         function mb_substr_split_unicode( $str, $splitPos ) {
  62                 return Fallback::mb_substr_split_unicode( $str, $splitPos );
  63         }
  64 }
  65
  66 if ( !function_exists( 'mb_strlen' ) ) {
  67         /**
  68          * @codeCoverageIgnore
  69          * @return int
  70          */
  71         function mb_strlen( $str, $enc = '' ) {
  72                 return Fallback::mb_strlen( $str, $enc );
  73         }
  74 }
  75
  76 if ( !function_exists( 'mb_strpos' ) ) {
  77         /**
  78          * @codeCoverageIgnore
  79          * @return int
  80          */
  81         function mb_strpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  82                 return Fallback::mb_strpos( $haystack, $needle, $offset, $encoding );
  83         }
  84 }
  85
  86 if ( !function_exists( 'mb_strrpos' ) ) {
  87         /**
  88          * @codeCoverageIgnore
  89          * @return int
  90          */
  91         function mb_strrpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
  92                 return Fallback::mb_strrpos( $haystack, $needle, $offset, $encoding );
  93         }
  94 }
  95
  96 // gzdecode function only exists in PHP >= 5.4.0
  97 // http://php.net/gzdecode
  98 if ( !function_exists( 'gzdecode' ) ) {
  99         /**
 100          * @codeCoverageIgnore
 101          * @return string
 102          */
 103         function gzdecode( $data ) {
 104                 return gzinflate( substr( $data, 10, -8 ) );
 105         }
 106 }
 107 /// @endcond
 108
 109 /**
 110  * Like array_diff( $a, $b ) except that it works with two-dimensional arrays.
 111  * @param $a array
 112  * @param $b array
 113  * @return array
 114  */
 115 function wfArrayDiff2( $a, $b ) {
 116         return array_udiff( $a, $b, 'wfArrayDiff2_cmp' );
 117 }
 118
 119 /**
 120  * @param $a array|string
 121  * @param $b array|string
 122  * @return int
 123  */
 124 function wfArrayDiff2_cmp( $a, $b ) {
 125         if ( is_string( $a ) && is_string( $b ) ) {
 126                 return strcmp( $a, $b );
 127         } elseif ( count( $a ) !== count( $b ) ) {
 128                 return count( $a ) < count( $b ) ? -1 : 1;
 129         } else {
 130                 reset( $a );
 131                 reset( $b );
 132                 while ( ( list( , $valueA ) = each( $a ) ) && ( list( , $valueB ) = each( $b ) ) ) {
 133                         $cmp = strcmp( $valueA, $valueB );
 134                         if ( $cmp !== 0 ) {
 135                                 return $cmp;
 136                         }
 137                 }
 138                 return 0;
 139         }
 140 }
 141
 142 /**
 143  * Array lookup
 144  * Returns an array where the values in array $b are replaced by the
 145  * values in array $a with the corresponding keys
 146  *
 147  * @deprecated since 1.22; use array_intersect_key()
 148  * @param $a Array
 149  * @param $b Array
 150  * @return array
 151  */
 152 function wfArrayLookup( $a, $b ) {
 153         wfDeprecated( __FUNCTION__, '1.22' );
 154         return array_flip( array_intersect( array_flip( $a ), array_keys( $b ) ) );
 155 }
 156
 157 /**
 158  * Appends to second array if $value differs from that in $default
 159  *
 160  * @param $key String|Int
 161  * @param $value Mixed
 162  * @param $default Mixed
 163  * @param array $changed to alter
 164  * @throws MWException
 165  */
 166 function wfAppendToArrayIfNotDefault( $key, $value, $default, &$changed ) {
 167         if ( is_null( $changed ) ) {
 168                 throw new MWException( 'GlobalFunctions::wfAppendToArrayIfNotDefault got null' );
 169         }
 170         if ( $default[$key] !== $value ) {
 171                 $changed[$key] = $value;
 172         }
 173 }
 174
 175 /**
 176  * Backwards array plus for people who haven't bothered to read the PHP manual
 177  * XXX: will not darn your socks for you.
 178  *
 179  * @deprecated since 1.22; use array_replace()
 180  * @param $array1 Array
 181  * @param [$array2, [...]] Arrays
 182  * @return Array
 183  */
 184 function wfArrayMerge( $array1/* ... */ ) {
 185         wfDeprecated( __FUNCTION__, '1.22' );
 186         $args = func_get_args();
 187         $args = array_reverse( $args, true );
 188         $out = array();
 189         foreach ( $args as $arg ) {
 190                 $out += $arg;
 191         }
 192         return $out;
 193 }
 194
 195 /**
 196  * Merge arrays in the style of getUserPermissionsErrors, with duplicate removal
 197  * e.g.
 198  *      wfMergeErrorArrays(
 199  *              array( array( 'x' ) ),
 200  *              array( array( 'x', '2' ) ),
 201  *              array( array( 'x' ) ),
 202  *              array( array( 'y' ) )
 203  *      );
 204  * returns:
 205  *              array(
 206  *              array( 'x', '2' ),
 207  *              array( 'x' ),
 208  *              array( 'y' )
 209  *      )
 210  * @param varargs
 211  * @return Array
 212  */
 213 function wfMergeErrorArrays( /*...*/ ) {
 214         $args = func_get_args();
 215         $out = array();
 216         foreach ( $args as $errors ) {
 217                 foreach ( $errors as $params ) {
 218                         # @todo FIXME: Sometimes get nested arrays for $params,
 219                         # which leads to E_NOTICEs
 220                         $spec = implode( "\t", $params );
 221                         $out[$spec] = $params;
 222                 }
 223         }
 224         return array_values( $out );
 225 }
 226
 227 /**
 228  * Insert array into another array after the specified *KEY*
 229  *
 230  * @param array $array The array.
 231  * @param array $insert The array to insert.
 232  * @param $after Mixed: The key to insert after
 233  * @return Array
 234  */
 235 function wfArrayInsertAfter( array $array, array $insert, $after ) {
 236         // Find the offset of the element to insert after.
 237         $keys = array_keys( $array );
 238         $offsetByKey = array_flip( $keys );
 239
 240         $offset = $offsetByKey[$after];
 241
 242         // Insert at the specified offset
 243         $before = array_slice( $array, 0, $offset + 1, true );
 244         $after = array_slice( $array, $offset + 1, count( $array ) - $offset, true );
 245
 246         $output = $before + $insert + $after;
 247
 248         return $output;
 249 }
 250
 251 /**
 252  * Recursively converts the parameter (an object) to an array with the same data
 253  *
 254  * @param $objOrArray Object|Array
 255  * @param $recursive Bool
 256  * @return Array
 257  */
 258 function wfObjectToArray( $objOrArray, $recursive = true ) {
 259         $array = array();
 260         if ( is_object( $objOrArray ) ) {
 261                 $objOrArray = get_object_vars( $objOrArray );
 262         }
 263         foreach ( $objOrArray as $key => $value ) {
 264                 if ( $recursive && ( is_object( $value ) || is_array( $value ) ) ) {
 265                         $value = wfObjectToArray( $value );
 266                 }
 267
 268                 $array[$key] = $value;
 269         }
 270
 271         return $array;
 272 }
 273
 274 /**
 275  * Get a random decimal value between 0 and 1, in a way
 276  * not likely to give duplicate values for any realistic
 277  * number of articles.
 278  *
 279  * @return string
 280  */
 281 function wfRandom() {
 282         # The maximum random value is "only" 2^31-1, so get two random
 283         # values to reduce the chance of dupes
 284         $max = mt_getrandmax() + 1;
 285         $rand = number_format( ( mt_rand() * $max + mt_rand() ) / $max / $max, 12, '.', '' );
 286
 287         return $rand;
 288 }
 289
 290 /**
 291  * Get a random string containing a number of pseudo-random hex
 292  * characters.
 293  * @note This is not secure, if you are trying to generate some sort
 294  *       of token please use MWCryptRand instead.
 295  *
 296  * @param int $length The length of the string to generate
 297  * @return String
 298  * @since 1.20
 299  */
 300 function wfRandomString( $length = 32 ) {
 301         $str = '';
 302         for ( $n = 0; $n < $length; $n += 7 ) {
 303                 $str .= sprintf( '%07x', mt_rand() & 0xfffffff );
 304         }
 305         return substr( $str, 0, $length );
 306 }
 307
 308 /**
 309  * We want some things to be included as literal characters in our title URLs
 310  * for prettiness, which urlencode encodes by default.  According to RFC 1738,
 311  * all of the following should be safe:
 312  *
 313  * ;:@&=$-_.+!*'(),
 314  *
 315  * But + is not safe because it's used to indicate a space; &= are only safe in
 316  * paths and not in queries (and we don't distinguish here); ' seems kind of
 317  * scary; and urlencode() doesn't touch -_. to begin with.  Plus, although /
 318  * is reserved, we don't care.  So the list we unescape is:
 319  *
 320  * ;:@$!*(),/
 321  *
 322  * However, IIS7 redirects fail when the url contains a colon (Bug 22709),
 323  * so no fancy : for IIS7.
 324  *
 325  * %2F in the page titles seems to fatally break for some reason.
 326  *
 327  * @param $s String:
 328  * @return string
 329  */
 330 function wfUrlencode( $s ) {
 331         static $needle;
 332
 333         if ( is_null( $s ) ) {
 334                 $needle = null;
 335                 return '';
 336         }
 337
 338         if ( is_null( $needle ) ) {
 339                 $needle = array( '%3B', '%40', '%24', '%21', '%2A', '%28', '%29', '%2C', '%2F' );
 340                 if ( !isset( $_SERVER['SERVER_SOFTWARE'] ) ||
 341                         ( strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/7' ) === false )
 342                 ) {
 343                         $needle[] = '%3A';
 344                 }
 345         }
 346
 347         $s = urlencode( $s );
 348         $s = str_ireplace(
 349                 $needle,
 350                 array( ';', '@', '$', '!', '*', '(', ')', ',', '/', ':' ),
 351                 $s
 352         );
 353
 354         return $s;
 355 }
 356
 357 /**
 358  * This function takes two arrays as input, and returns a CGI-style string, e.g.
 359  * "days=7&limit=100". Options in the first array override options in the second.
 360  * Options set to null or false will not be output.
 361  *
 362  * @param array $array1 ( String|Array )
 363  * @param array $array2 ( String|Array )
 364  * @param $prefix String
 365  * @return String
 366  */
 367 function wfArrayToCgi( $array1, $array2 = null, $prefix = '' ) {
 368         if ( !is_null( $array2 ) ) {
 369                 $array1 = $array1 + $array2;
 370         }
 371
 372         $cgi = '';
 373         foreach ( $array1 as $key => $value ) {
 374                 if ( !is_null( $value ) && $value !== false ) {
 375                         if ( $cgi != '' ) {
 376                                 $cgi .= '&';
 377                         }
 378                         if ( $prefix !== '' ) {
 379                                 $key = $prefix . "[$key]";
 380                         }
 381                         if ( is_array( $value ) ) {
 382                                 $firstTime = true;
 383                                 foreach ( $value as $k => $v ) {
 384                                         $cgi .= $firstTime ? '' : '&';
 385                                         if ( is_array( $v ) ) {
 386                                                 $cgi .= wfArrayToCgi( $v, null, $key . "[$k]" );
 387                                         } else {
 388                                                 $cgi .= urlencode( $key . "[$k]" ) . '=' . urlencode( $v );
 389                                         }
 390                                         $firstTime = false;
 391                                 }
 392                         } else {
 393                                 if ( is_object( $value ) ) {
 394                                         $value = $value->__toString();
 395                                 }
 396                                 $cgi .= urlencode( $key ) . '=' . urlencode( $value );
 397                         }
 398                 }
 399         }
 400         return $cgi;
 401 }
 402
 403 /**
 404  * This is the logical opposite of wfArrayToCgi(): it accepts a query string as
 405  * its argument and returns the same string in array form.  This allows compatibility
 406  * with legacy functions that accept raw query strings instead of nice
 407  * arrays.  Of course, keys and values are urldecode()d.
 408  *
 409  * @param string $query query string
 410  * @return array Array version of input
 411  */
 412 function wfCgiToArray( $query ) {
 413         if ( isset( $query[0] ) && $query[0] == '?' ) {
 414                 $query = substr( $query, 1 );
 415         }
 416         $bits = explode( '&', $query );
 417         $ret = array();
 418         foreach ( $bits as $bit ) {
 419                 if ( $bit === '' ) {
 420                         continue;
 421                 }
 422                 if ( strpos( $bit, '=' ) === false ) {
 423                         // Pieces like &qwerty become 'qwerty' => '' (at least this is what php does)
 424                         $key = $bit;
 425                         $value = '';
 426                 } else {
 427                         list( $key, $value ) = explode( '=', $bit );
 428                 }
 429                 $key = urldecode( $key );
 430                 $value = urldecode( $value );
 431                 if ( strpos( $key, '[' ) !== false ) {
 432                         $keys = array_reverse( explode( '[', $key ) );
 433                         $key = array_pop( $keys );
 434                         $temp = $value;
 435                         foreach ( $keys as $k ) {
 436                                 $k = substr( $k, 0, -1 );
 437                                 $temp = array( $k => $temp );
 438                         }
 439                         if ( isset( $ret[$key] ) ) {
 440                                 $ret[$key] = array_merge( $ret[$key], $temp );
 441                         } else {
 442                                 $ret[$key] = $temp;
 443                         }
 444                 } else {
 445                         $ret[$key] = $value;
 446                 }
 447         }
 448         return $ret;
 449 }
 450
 451 /**
 452  * Append a query string to an existing URL, which may or may not already
 453  * have query string parameters already. If so, they will be combined.
 454  *
 455  * @param $url String
 456  * @param $query Mixed: string or associative array
 457  * @return string
 458  */
 459 function wfAppendQuery( $url, $query ) {
 460         if ( is_array( $query ) ) {
 461                 $query = wfArrayToCgi( $query );
 462         }
 463         if ( $query != '' ) {
 464                 if ( false === strpos( $url, '?' ) ) {
 465                         $url .= '?';
 466                 } else {
 467                         $url .= '&';
 468                 }
 469                 $url .= $query;
 470         }
 471         return $url;
 472 }
 473
 474 /**
 475  * Expand a potentially local URL to a fully-qualified URL. Assumes $wgServer
 476  * is correct.
 477  *
 478  * The meaning of the PROTO_* constants is as follows:
 479  * PROTO_HTTP: Output a URL starting with http://
 480  * PROTO_HTTPS: Output a URL starting with https://
 481  * PROTO_RELATIVE: Output a URL starting with // (protocol-relative URL)
 482  * PROTO_CURRENT: Output a URL starting with either http:// or https:// , depending
 483  *    on which protocol was used for the current incoming request
 484  * PROTO_CANONICAL: For URLs without a domain, like /w/index.php , use $wgCanonicalServer.
 485  *    For protocol-relative URLs, use the protocol of $wgCanonicalServer
 486  * PROTO_INTERNAL: Like PROTO_CANONICAL, but uses $wgInternalServer instead of $wgCanonicalServer
 487  *
 488  * @todo this won't work with current-path-relative URLs
 489  * like "subdir/foo.html", etc.
 490  *
 491  * @param string $url either fully-qualified or a local path + query
 492  * @param $defaultProto Mixed: one of the PROTO_* constants. Determines the
 493  *    protocol to use if $url or $wgServer is protocol-relative
 494  * @return string Fully-qualified URL, current-path-relative URL or false if
 495  *    no valid URL can be constructed
 496  */
 497 function wfExpandUrl( $url, $defaultProto = PROTO_CURRENT ) {
 498         global $wgServer, $wgCanonicalServer, $wgInternalServer, $wgRequest;
 499         if ( $defaultProto === PROTO_CANONICAL ) {
 500                 $serverUrl = $wgCanonicalServer;
 501         } elseif ( $defaultProto === PROTO_INTERNAL && $wgInternalServer !== false ) {
 502                 // Make $wgInternalServer fall back to $wgServer if not set
 503                 $serverUrl = $wgInternalServer;
 504         } else {
 505                 $serverUrl = $wgServer;
 506                 if ( $defaultProto === PROTO_CURRENT ) {
 507                         $defaultProto = $wgRequest->getProtocol() . '://';
 508                 }
 509         }
 510
 511         // Analyze $serverUrl to obtain its protocol
 512         $bits = wfParseUrl( $serverUrl );
 513         $serverHasProto = $bits && $bits['scheme'] != '';
 514
 515         if ( $defaultProto === PROTO_CANONICAL || $defaultProto === PROTO_INTERNAL ) {
 516                 if ( $serverHasProto ) {
 517                         $defaultProto = $bits['scheme'] . '://';
 518                 } else {
 519                         // $wgCanonicalServer or $wgInternalServer doesn't have a protocol.
 520                         // This really isn't supposed to happen. Fall back to HTTP in this
 521                         // ridiculous case.
 522                         $defaultProto = PROTO_HTTP;
 523                 }
 524         }
 525
 526         $defaultProtoWithoutSlashes = substr( $defaultProto, 0, -2 );
 527
 528         if ( substr( $url, 0, 2 ) == '//' ) {
 529                 $url = $defaultProtoWithoutSlashes . $url;
 530         } elseif ( substr( $url, 0, 1 ) == '/' ) {
 531                 // If $serverUrl is protocol-relative, prepend $defaultProtoWithoutSlashes,
 532                 // otherwise leave it alone.
 533                 $url = ( $serverHasProto ? '' : $defaultProtoWithoutSlashes ) . $serverUrl . $url;
 534         }
 535
 536         $bits = wfParseUrl( $url );
 537         if ( $bits && isset( $bits['path'] ) ) {
 538                 $bits['path'] = wfRemoveDotSegments( $bits['path'] );
 539                 return wfAssembleUrl( $bits );
 540         } elseif ( $bits ) {
 541                 # No path to expand
 542                 return $url;
 543         } elseif ( substr( $url, 0, 1 ) != '/' ) {
 544                 # URL is a relative path
 545                 return wfRemoveDotSegments( $url );
 546         }
 547
 548         # Expanded URL is not valid.
 549         return false;
 550 }
 551
 552 /**
 553  * This function will reassemble a URL parsed with wfParseURL.  This is useful
 554  * if you need to edit part of a URL and put it back together.
 555  *
 556  * This is the basic structure used (brackets contain keys for $urlParts):
 557  * [scheme][delimiter][user]:[pass]@[host]:[port][path]?[query]#[fragment]
 558  *
 559  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 560  *
 561  * @since 1.19
 562  * @param array $urlParts URL parts, as output from wfParseUrl
 563  * @return string URL assembled from its component parts
 564  */
 565 function wfAssembleUrl( $urlParts ) {
 566         $result = '';
 567
 568         if ( isset( $urlParts['delimiter'] ) ) {
 569                 if ( isset( $urlParts['scheme'] ) ) {
 570                         $result .= $urlParts['scheme'];
 571                 }
 572
 573                 $result .= $urlParts['delimiter'];
 574         }
 575
 576         if ( isset( $urlParts['host'] ) ) {
 577                 if ( isset( $urlParts['user'] ) ) {
 578                         $result .= $urlParts['user'];
 579                         if ( isset( $urlParts['pass'] ) ) {
 580                                 $result .= ':' . $urlParts['pass'];
 581                         }
 582                         $result .= '@';
 583                 }
 584
 585                 $result .= $urlParts['host'];
 586
 587                 if ( isset( $urlParts['port'] ) ) {
 588                         $result .= ':' . $urlParts['port'];
 589                 }
 590         }
 591
 592         if ( isset( $urlParts['path'] ) ) {
 593                 $result .= $urlParts['path'];
 594         }
 595
 596         if ( isset( $urlParts['query'] ) ) {
 597                 $result .= '?' . $urlParts['query'];
 598         }
 599
 600         if ( isset( $urlParts['fragment'] ) ) {
 601                 $result .= '#' . $urlParts['fragment'];
 602         }
 603
 604         return $result;
 605 }
 606
 607 /**
 608  * Remove all dot-segments in the provided URL path.  For example,
 609  * '/a/./b/../c/' becomes '/a/c/'.  For details on the algorithm, please see
 610  * RFC3986 section 5.2.4.
 611  *
 612  * @todo Need to integrate this into wfExpandUrl (bug 32168)
 613  *
 614  * @param string $urlPath URL path, potentially containing dot-segments
 615  * @return string URL path with all dot-segments removed
 616  */
 617 function wfRemoveDotSegments( $urlPath ) {
 618         $output = '';
 619         $inputOffset = 0;
 620         $inputLength = strlen( $urlPath );
 621
 622         while ( $inputOffset < $inputLength ) {
 623                 $prefixLengthOne = substr( $urlPath, $inputOffset, 1 );
 624                 $prefixLengthTwo = substr( $urlPath, $inputOffset, 2 );
 625                 $prefixLengthThree = substr( $urlPath, $inputOffset, 3 );
 626                 $prefixLengthFour = substr( $urlPath, $inputOffset, 4 );
 627                 $trimOutput = false;
 628
 629                 if ( $prefixLengthTwo == './' ) {
 630                         # Step A, remove leading "./"
 631                         $inputOffset += 2;
 632                 } elseif ( $prefixLengthThree == '../' ) {
 633                         # Step A, remove leading "../"
 634                         $inputOffset += 3;
 635                 } elseif ( ( $prefixLengthTwo == '/.' ) && ( $inputOffset + 2 == $inputLength ) ) {
 636                         # Step B, replace leading "/.$" with "/"
 637                         $inputOffset += 1;
 638                         $urlPath[$inputOffset] = '/';
 639                 } elseif ( $prefixLengthThree == '/./' ) {
 640                         # Step B, replace leading "/./" with "/"
 641                         $inputOffset += 2;
 642                 } elseif ( $prefixLengthThree == '/..' && ( $inputOffset + 3 == $inputLength ) ) {
 643                         # Step C, replace leading "/..$" with "/" and
 644                         # remove last path component in output
 645                         $inputOffset += 2;
 646                         $urlPath[$inputOffset] = '/';
 647                         $trimOutput = true;
 648                 } elseif ( $prefixLengthFour == '/../' ) {
 649                         # Step C, replace leading "/../" with "/" and
 650                         # remove last path component in output
 651                         $inputOffset += 3;
 652                         $trimOutput = true;
 653                 } elseif ( ( $prefixLengthOne == '.' ) && ( $inputOffset + 1 == $inputLength ) ) {
 654                         # Step D, remove "^.$"
 655                         $inputOffset += 1;
 656                 } elseif ( ( $prefixLengthTwo == '..' ) && ( $inputOffset + 2 == $inputLength ) ) {
 657                         # Step D, remove "^..$"
 658                         $inputOffset += 2;
 659                 } else {
 660                         # Step E, move leading path segment to output
 661                         if ( $prefixLengthOne == '/' ) {
 662                                 $slashPos = strpos( $urlPath, '/', $inputOffset + 1 );
 663                         } else {
 664                                 $slashPos = strpos( $urlPath, '/', $inputOffset );
 665                         }
 666                         if ( $slashPos === false ) {
 667                                 $output .= substr( $urlPath, $inputOffset );
 668                                 $inputOffset = $inputLength;
 669                         } else {
 670                                 $output .= substr( $urlPath, $inputOffset, $slashPos - $inputOffset );
 671                                 $inputOffset += $slashPos - $inputOffset;
 672                         }
 673                 }
 674
 675                 if ( $trimOutput ) {
 676                         $slashPos = strrpos( $output, '/' );
 677                         if ( $slashPos === false ) {
 678                                 $output = '';
 679                         } else {
 680                                 $output = substr( $output, 0, $slashPos );
 681                         }
 682                 }
 683         }
 684
 685         return $output;
 686 }
 687
 688 /**
 689  * Returns a regular expression of url protocols
 690  *
 691  * @param bool $includeProtocolRelative If false, remove '//' from the returned protocol list.
 692  *        DO NOT USE this directly, use wfUrlProtocolsWithoutProtRel() instead
 693  * @return String
 694  */
 695 function wfUrlProtocols( $includeProtocolRelative = true ) {
 696         global $wgUrlProtocols;
 697
 698         // Cache return values separately based on $includeProtocolRelative
 699         static $withProtRel = null, $withoutProtRel = null;
 700         $cachedValue = $includeProtocolRelative ? $withProtRel : $withoutProtRel;
 701         if ( !is_null( $cachedValue ) ) {
 702                 return $cachedValue;
 703         }
 704
 705         // Support old-style $wgUrlProtocols strings, for backwards compatibility
 706         // with LocalSettings files from 1.5
 707         if ( is_array( $wgUrlProtocols ) ) {
 708                 $protocols = array();
 709                 foreach ( $wgUrlProtocols as $protocol ) {
 710                         // Filter out '//' if !$includeProtocolRelative
 711                         if ( $includeProtocolRelative || $protocol !== '//' ) {
 712                                 $protocols[] = preg_quote( $protocol, '/' );
 713                         }
 714                 }
 715
 716                 $retval = implode( '|', $protocols );
 717         } else {
 718                 // Ignore $includeProtocolRelative in this case
 719                 // This case exists for pre-1.6 compatibility, and we can safely assume
 720                 // that '//' won't appear in a pre-1.6 config because protocol-relative
 721                 // URLs weren't supported until 1.18
 722                 $retval = $wgUrlProtocols;
 723         }
 724
 725         // Cache return value
 726         if ( $includeProtocolRelative ) {
 727                 $withProtRel = $retval;
 728         } else {
 729                 $withoutProtRel = $retval;
 730         }
 731         return $retval;
 732 }
 733
 734 /**
 735  * Like wfUrlProtocols(), but excludes '//' from the protocol list. Use this if
 736  * you need a regex that matches all URL protocols but does not match protocol-
 737  * relative URLs
 738  * @return String
 739  */
 740 function wfUrlProtocolsWithoutProtRel() {
 741         return wfUrlProtocols( false );
 742 }
 743
 744 /**
 745  * parse_url() work-alike, but non-broken.  Differences:
 746  *
 747  * 1) Does not raise warnings on bad URLs (just returns false).
 748  * 2) Handles protocols that don't use :// (e.g., mailto: and news:, as well as
 749  *    protocol-relative URLs) correctly.
 750  * 3) Adds a "delimiter" element to the array, either '://', ':' or '//' (see (2)).
 751  *
 752  * @param string $url a URL to parse
 753  * @return Array: bits of the URL in an associative array, per PHP docs
 754  */
 755 function wfParseUrl( $url ) {
 756         global $wgUrlProtocols; // Allow all protocols defined in DefaultSettings/LocalSettings.php
 757
 758         // Protocol-relative URLs are handled really badly by parse_url(). It's so
 759         // bad that the easiest way to handle them is to just prepend 'http:' and
 760         // strip the protocol out later.
 761         $wasRelative = substr( $url, 0, 2 ) == '//';
 762         if ( $wasRelative ) {
 763                 $url = "http:$url";
 764         }
 765         wfSuppressWarnings();
 766         $bits = parse_url( $url );
 767         wfRestoreWarnings();
 768         // parse_url() returns an array without scheme for some invalid URLs, e.g.
 769         // parse_url("%0Ahttp://example.com") == array( 'host' => '%0Ahttp', 'path' => 'example.com' )
 770         if ( !$bits || !isset( $bits['scheme'] ) ) {
 771                 return false;
 772         }
 773
 774         // parse_url() incorrectly handles schemes case-sensitively. Convert it to lowercase.
 775         $bits['scheme'] = strtolower( $bits['scheme'] );
 776
 777         // most of the protocols are followed by ://, but mailto: and sometimes news: not, check for it
 778         if ( in_array( $bits['scheme'] . '://', $wgUrlProtocols ) ) {
 779                 $bits['delimiter'] = '://';
 780         } elseif ( in_array( $bits['scheme'] . ':', $wgUrlProtocols ) ) {
 781                 $bits['delimiter'] = ':';
 782                 // parse_url detects for news: and mailto: the host part of an url as path
 783                 // We have to correct this wrong detection
 784                 if ( isset( $bits['path'] ) ) {
 785                         $bits['host'] = $bits['path'];
 786                         $bits['path'] = '';
 787                 }
 788         } else {
 789                 return false;
 790         }
 791
 792         /* Provide an empty host for eg. file:/// urls (see bug 28627) */
 793         if ( !isset( $bits['host'] ) ) {
 794                 $bits['host'] = '';
 795
 796                 // bug 45069
 797                 if ( isset( $bits['path'] ) ) {
 798                         /* parse_url loses the third / for file:///c:/ urls (but not on variants) */
 799                         if ( substr( $bits['path'], 0, 1 ) !== '/' ) {
 800                                 $bits['path'] = '/' . $bits['path'];
 801                         }
 802                 } else {
 803                         $bits['path'] = '';
 804                 }
 805         }
 806
 807         // If the URL was protocol-relative, fix scheme and delimiter
 808         if ( $wasRelative ) {
 809                 $bits['scheme'] = '';
 810                 $bits['delimiter'] = '//';
 811         }
 812         return $bits;
 813 }
 814
 815 /**
 816  * Take a URL, make sure it's expanded to fully qualified, and replace any
 817  * encoded non-ASCII Unicode characters with their UTF-8 original forms
 818  * for more compact display and legibility for local audiences.
 819  *
 820  * @todo handle punycode domains too
 821  *
 822  * @param $url string
 823  * @return string
 824  */
 825 function wfExpandIRI( $url ) {
 826         return preg_replace_callback(
 827                 '/((?:%[89A-F][0-9A-F])+)/i',
 828                 'wfExpandIRI_callback',
 829                 wfExpandUrl( $url )
 830         );
 831 }
 832
 833 /**
 834  * Private callback for wfExpandIRI
 835  * @param array $matches
 836  * @return string
 837  */
 838 function wfExpandIRI_callback( $matches ) {
 839         return urldecode( $matches[1] );
 840 }
 841
 842 /**
 843  * Make URL indexes, appropriate for the el_index field of externallinks.
 844  *
 845  * @param $url String
 846  * @return array
 847  */
 848 function wfMakeUrlIndexes( $url ) {
 849         $bits = wfParseUrl( $url );
 850
 851         // Reverse the labels in the hostname, convert to lower case
 852         // For emails reverse domainpart only
 853         if ( $bits['scheme'] == 'mailto' ) {
 854                 $mailparts = explode( '@', $bits['host'], 2 );
 855                 if ( count( $mailparts ) === 2 ) {
 856                         $domainpart = strtolower( implode( '.', array_reverse( explode( '.', $mailparts[1] ) ) ) );
 857                 } else {
 858                         // No domain specified, don't mangle it
 859                         $domainpart = '';
 860                 }
 861                 $reversedHost = $domainpart . '@' . $mailparts[0];
 862         } else {
 863                 $reversedHost = strtolower( implode( '.', array_reverse( explode( '.', $bits['host'] ) ) ) );
 864         }
 865         // Add an extra dot to the end
 866         // Why? Is it in wrong place in mailto links?
 867         if ( substr( $reversedHost, -1, 1 ) !== '.' ) {
 868                 $reversedHost .= '.';
 869         }
 870         // Reconstruct the pseudo-URL
 871         $prot = $bits['scheme'];
 872         $index = $prot . $bits['delimiter'] . $reversedHost;
 873         // Leave out user and password. Add the port, path, query and fragment
 874         if ( isset( $bits['port'] ) ) {
 875                 $index .= ':' . $bits['port'];
 876         }
 877         if ( isset( $bits['path'] ) ) {
 878                 $index .= $bits['path'];
 879         } else {
 880                 $index .= '/';
 881         }
 882         if ( isset( $bits['query'] ) ) {
 883                 $index .= '?' . $bits['query'];
 884         }
 885         if ( isset( $bits['fragment'] ) ) {
 886                 $index .= '#' . $bits['fragment'];
 887         }
 888
 889         if ( $prot == '' ) {
 890                 return array( "http:$index", "https:$index" );
 891         } else {
 892                 return array( $index );
 893         }
 894 }
 895
 896 /**
 897  * Check whether a given URL has a domain that occurs in a given set of domains
 898  * @param string $url URL
 899  * @param array $domains Array of domains (strings)
 900  * @return bool True if the host part of $url ends in one of the strings in $domains
 901  */
 902 function wfMatchesDomainList( $url, $domains ) {
 903         $bits = wfParseUrl( $url );
 904         if ( is_array( $bits ) && isset( $bits['host'] ) ) {
 905                 $host = '.' . $bits['host'];
 906                 foreach ( (array)$domains as $domain ) {
 907                         $domain = '.' . $domain;
 908                         if ( substr( $host, -strlen( $domain ) ) === $domain ) {
 909                                 return true;
 910                         }
 911                 }
 912         }
 913         return false;
 914 }
 915
 916 /**
 917  * Sends a line to the debug log if enabled or, optionally, to a comment in output.
 918  * In normal operation this is a NOP.
 919  *
 920  * Controlling globals:
 921  * $wgDebugLogFile - points to the log file
 922  * $wgProfileOnly - if set, normal debug messages will not be recorded.
 923  * $wgDebugRawPage - if false, 'action=raw' hits will not result in debug output.
 924  * $wgDebugComments - if on, some debug items may appear in comments in the HTML output.
 925  *
 926  * @param $text String
 927  * @param bool $logonly set true to avoid appearing in HTML when $wgDebugComments is set
 928  */
 929 function wfDebug( $text, $logonly = false ) {
 930         global $wgDebugLogFile, $wgProfileOnly, $wgDebugRawPage, $wgDebugLogPrefix;
 931
 932         if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
 933                 return;
 934         }
 935
 936         $timer = wfDebugTimer();
 937         if ( $timer !== '' ) {
 938                 $text = preg_replace( '/[^\n]/', $timer . '\0', $text, 1 );
 939         }
 940
 941         if ( !$logonly ) {
 942                 MWDebug::debugMsg( $text );
 943         }
 944
 945         if ( $wgDebugLogFile != '' && !$wgProfileOnly ) {
 946                 # Strip unprintables; they can switch terminal modes when binary data
 947                 # gets dumped, which is pretty annoying.
 948                 $text = preg_replace( '![\x00-\x08\x0b\x0c\x0e-\x1f]!', ' ', $text );
 949                 $text = $wgDebugLogPrefix . $text;
 950                 wfErrorLog( $text, $wgDebugLogFile );
 951         }
 952 }
 953
 954 /**
 955  * Returns true if debug logging should be suppressed if $wgDebugRawPage = false
 956  * @return bool
 957  */
 958 function wfIsDebugRawPage() {
 959         static $cache;
 960         if ( $cache !== null ) {
 961                 return $cache;
 962         }
 963         # Check for raw action using $_GET not $wgRequest, since the latter might not be initialised yet
 964         if ( ( isset( $_GET['action'] ) && $_GET['action'] == 'raw' )
 965                 || (
 966                         isset( $_SERVER['SCRIPT_NAME'] )
 967                         && substr( $_SERVER['SCRIPT_NAME'], -8 ) == 'load.php'
 968                 )
 969         ) {
 970                 $cache = true;
 971         } else {
 972                 $cache = false;
 973         }
 974         return $cache;
 975 }
 976
 977 /**
 978  * Get microsecond timestamps for debug logs
 979  *
 980  * @return string
 981  */
 982 function wfDebugTimer() {
 983         global $wgDebugTimestamps, $wgRequestTime;
 984
 985         if ( !$wgDebugTimestamps ) {
 986                 return '';
 987         }
 988
 989         $prefix = sprintf( "%6.4f", microtime( true ) - $wgRequestTime );
 990         $mem = sprintf( "%5.1fM", ( memory_get_usage( true ) / ( 1024 * 1024 ) ) );
 991         return "$prefix $mem  ";
 992 }
 993
 994 /**
 995  * Send a line giving PHP memory usage.
 996  *
 997  * @param bool $exact print exact values instead of kilobytes (default: false)
 998  */
 999 function wfDebugMem( $exact = false ) {
1000         $mem = memory_get_usage();
1001         if ( !$exact ) {
1002                 $mem = floor( $mem / 1024 ) . ' kilobytes';
1003         } else {
1004                 $mem .= ' bytes';
1005         }
1006         wfDebug( "Memory usage: $mem\n" );
1007 }
1008
1009 /**
1010  * Send a line to a supplementary debug log file, if configured, or main debug log if not.
1011  * To configure a supplementary log file, set $wgDebugLogGroups[$logGroup] to a string
1012  * filename or an associative array mapping 'destination' to the desired filename. The
1013  * associative array may also contain a 'sample' key with an integer value, specifying
1014  * a sampling factor.
1015  *
1016  * @since 1.23 support for sampling log messages via $wgDebugLogGroups.
1017  *
1018  * @param $logGroup String
1019  * @param $text String
1020  * @param bool $public whether to log the event in the public log if no private
1021  *                     log file is specified, (default true)
1022  */
1023 function wfDebugLog( $logGroup, $text, $public = true ) {
1024         global $wgDebugLogGroups;
1025         $text = trim( $text ) . "\n";
1026
1027         if ( !isset( $wgDebugLogGroups[$logGroup] ) ) {
1028                 if ( $public === true ) {
1029                         wfDebug( "[$logGroup] $text", false );
1030                 }
1031                 return;
1032         }
1033
1034         $logConfig = $wgDebugLogGroups[$logGroup];
1035         if ( is_array( $logConfig ) ) {
1036                 if ( isset( $logConfig['sample'] ) && mt_rand( 1, $logConfig['sample'] ) !== 1 ) {
1037                         return;
1038                 }
1039                 $destination = $logConfig['destination'];
1040         } else {
1041                 $destination = strval( $logConfig );
1042         }
1043
1044         $time = wfTimestamp( TS_DB );
1045         $wiki = wfWikiID();
1046         $host = wfHostname();
1047         wfErrorLog( "$time $host $wiki: $text", $destination );
1048 }
1049
1050 /**
1051  * Log for database errors
1052  *
1053  * @param string $text database error message.
1054  */
1055 function wfLogDBError( $text ) {
1056         global $wgDBerrorLog, $wgDBerrorLogTZ;
1057         static $logDBErrorTimeZoneObject = null;
1058
1059         if ( $wgDBerrorLog ) {
1060                 $host = wfHostname();
1061                 $wiki = wfWikiID();
1062
1063                 if ( $wgDBerrorLogTZ && !$logDBErrorTimeZoneObject ) {
1064                         $logDBErrorTimeZoneObject = new DateTimeZone( $wgDBerrorLogTZ );
1065                 }
1066
1067                 // Workaround for https://bugs.php.net/bug.php?id=52063
1068                 // Can be removed when min PHP > 5.3.2
1069                 if ( $logDBErrorTimeZoneObject === null ) {
1070                         $d = date_create( "now" );
1071                 } else {
1072                         $d = date_create( "now", $logDBErrorTimeZoneObject );
1073                 }
1074
1075                 $date = $d->format( 'D M j G:i:s T Y' );
1076
1077                 $text = "$date\t$host\t$wiki\t$text";
1078                 wfErrorLog( $text, $wgDBerrorLog );
1079         }
1080 }
1081
1082 /**
1083  * Throws a warning that $function is deprecated
1084  *
1085  * @param $function String
1086  * @param string|bool $version Version of MediaWiki that the function
1087  *    was deprecated in (Added in 1.19).
1088  * @param string|bool $component Added in 1.19.
1089  * @param $callerOffset integer: How far up the call stack is the original
1090  *    caller. 2 = function that called the function that called
1091  *    wfDeprecated (Added in 1.20)
1092  *
1093  * @return null
1094  */
1095 function wfDeprecated( $function, $version = false, $component = false, $callerOffset = 2 ) {
1096         MWDebug::deprecated( $function, $version, $component, $callerOffset + 1 );
1097 }
1098
1099 /**
1100  * Send a warning either to the debug log or in a PHP error depending on
1101  * $wgDevelopmentWarnings. To log warnings in production, use wfLogWarning() instead.
1102  *
1103  * @param string $msg message to send
1104  * @param $callerOffset Integer: number of items to go back in the backtrace to
1105  *        find the correct caller (1 = function calling wfWarn, ...)
1106  * @param $level Integer: PHP error level; defaults to E_USER_NOTICE;
1107  *        only used when $wgDevelopmentWarnings is true
1108  */
1109 function wfWarn( $msg, $callerOffset = 1, $level = E_USER_NOTICE ) {
1110         MWDebug::warning( $msg, $callerOffset + 1, $level, 'auto' );
1111 }
1112
1113 /**
1114  * Send a warning as a PHP error and the debug log. This is intended for logging
1115  * warnings in production. For logging development warnings, use WfWarn instead.
1116  *
1117  * @param $msg String: message to send
1118  * @param $callerOffset Integer: number of items to go back in the backtrace to
1119  *        find the correct caller (1 = function calling wfLogWarning, ...)
1120  * @param $level Integer: PHP error level; defaults to E_USER_WARNING
1121  */
1122 function wfLogWarning( $msg, $callerOffset = 1, $level = E_USER_WARNING ) {
1123         MWDebug::warning( $msg, $callerOffset + 1, $level, 'production' );
1124 }
1125
1126 /**
1127  * Log to a file without getting "file size exceeded" signals.
1128  *
1129  * Can also log to TCP or UDP with the syntax udp://host:port/prefix. This will
1130  * send lines to the specified port, prefixed by the specified prefix and a space.
1131  *
1132  * @param $text String
1133  * @param string $file filename
1134  * @throws MWException
1135  */
1136 function wfErrorLog( $text, $file ) {
1137         if ( substr( $file, 0, 4 ) == 'udp:' ) {
1138                 # Needs the sockets extension
1139                 if ( preg_match( '!^(tcp|udp):(?://)?\[([0-9a-fA-F:]+)\]:(\d+)(?:/(.*))?$!', $file, $m ) ) {
1140                         // IPv6 bracketed host
1141                         $host = $m[2];
1142                         $port = intval( $m[3] );
1143                         $prefix = isset( $m[4] ) ? $m[4] : false;
1144                         $domain = AF_INET6;
1145                 } elseif ( preg_match( '!^(tcp|udp):(?://)?([a-zA-Z0-9.-]+):(\d+)(?:/(.*))?$!', $file, $m ) ) {
1146                         $host = $m[2];
1147                         if ( !IP::isIPv4( $host ) ) {
1148                                 $host = gethostbyname( $host );
1149                         }
1150                         $port = intval( $m[3] );
1151                         $prefix = isset( $m[4] ) ? $m[4] : false;
1152                         $domain = AF_INET;
1153                 } else {
1154                         throw new MWException( __METHOD__ . ': Invalid UDP specification' );
1155                 }
1156
1157                 // Clean it up for the multiplexer
1158                 if ( strval( $prefix ) !== '' ) {
1159                         $text = preg_replace( '/^/m', $prefix . ' ', $text );
1160
1161                         // Limit to 64KB
1162                         if ( strlen( $text ) > 65506 ) {
1163                                 $text = substr( $text, 0, 65506 );
1164                         }
1165
1166                         if ( substr( $text, -1 ) != "\n" ) {
1167                                 $text .= "\n";
1168                         }
1169                 } elseif ( strlen( $text ) > 65507 ) {
1170                         $text = substr( $text, 0, 65507 );
1171                 }
1172
1173                 $sock = socket_create( $domain, SOCK_DGRAM, SOL_UDP );
1174                 if ( !$sock ) {
1175                         return;
1176                 }
1177
1178                 socket_sendto( $sock, $text, strlen( $text ), 0, $host, $port );
1179                 socket_close( $sock );
1180         } else {
1181                 wfSuppressWarnings();
1182                 $exists = file_exists( $file );
1183                 $size = $exists ? filesize( $file ) : false;
1184                 if ( !$exists || ( $size !== false && $size + strlen( $text ) < 0x7fffffff ) ) {
1185                         file_put_contents( $file, $text, FILE_APPEND );
1186                 }
1187                 wfRestoreWarnings();
1188         }
1189 }
1190
1191 /**
1192  * @todo document
1193  */
1194 function wfLogProfilingData() {
1195         global $wgRequestTime, $wgDebugLogFile, $wgDebugRawPage, $wgRequest;
1196         global $wgProfileLimit, $wgUser;
1197
1198         StatCounter::singleton()->flush();
1199
1200         $profiler = Profiler::instance();
1201
1202         # Profiling must actually be enabled...
1203         if ( $profiler->isStub() ) {
1204                 return;
1205         }
1206
1207         // Get total page request time and only show pages that longer than
1208         // $wgProfileLimit time (default is 0)
1209         $elapsed = microtime( true ) - $wgRequestTime;
1210         if ( $elapsed <= $wgProfileLimit ) {
1211                 return;
1212         }
1213
1214         $profiler->logData();
1215
1216         // Check whether this should be logged in the debug file.
1217         if ( $wgDebugLogFile == '' || ( !$wgDebugRawPage && wfIsDebugRawPage() ) ) {
1218                 return;
1219         }
1220
1221         $forward = '';
1222         if ( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
1223                 $forward = ' forwarded for ' . $_SERVER['HTTP_X_FORWARDED_FOR'];
1224         }
1225         if ( !empty( $_SERVER['HTTP_CLIENT_IP'] ) ) {
1226                 $forward .= ' client IP ' . $_SERVER['HTTP_CLIENT_IP'];
1227         }
1228         if ( !empty( $_SERVER['HTTP_FROM'] ) ) {
1229                 $forward .= ' from ' . $_SERVER['HTTP_FROM'];
1230         }
1231         if ( $forward ) {
1232                 $forward = "\t(proxied via {$_SERVER['REMOTE_ADDR']}{$forward})";
1233         }
1234         // Don't load $wgUser at this late stage just for statistics purposes
1235         // @todo FIXME: We can detect some anons even if it is not loaded. See User::getId()
1236         if ( $wgUser->isItemLoaded( 'id' ) && $wgUser->isAnon() ) {
1237                 $forward .= ' anon';
1238         }
1239
1240         // Command line script uses a FauxRequest object which does not have
1241         // any knowledge about an URL and throw an exception instead.
1242         try {
1243                 $requestUrl = $wgRequest->getRequestURL();
1244         } catch ( MWException $e ) {
1245                 $requestUrl = 'n/a';
1246         }
1247
1248         $log = sprintf( "%s\t%04.3f\t%s\n",
1249                 gmdate( 'YmdHis' ), $elapsed,
1250                 urldecode( $requestUrl . $forward ) );
1251
1252         wfErrorLog( $log . $profiler->getOutput(), $wgDebugLogFile );
1253 }
1254
1255 /**
1256  * Increment a statistics counter
1257  *
1258  * @param $key String
1259  * @param $count Int
1260  * @return void
1261  */
1262 function wfIncrStats( $key, $count = 1 ) {
1263         StatCounter::singleton()->incr( $key, $count );
1264 }
1265
1266 /**
1267  * Check whether the wiki is in read-only mode.
1268  *
1269  * @return bool
1270  */
1271 function wfReadOnly() {
1272         return wfReadOnlyReason() !== false;
1273 }
1274
1275 /**
1276  * Get the value of $wgReadOnly or the contents of $wgReadOnlyFile.
1277  *
1278  * @return string|bool: String when in read-only mode; false otherwise
1279  */
1280 function wfReadOnlyReason() {
1281         global $wgReadOnly, $wgReadOnlyFile;
1282
1283         if ( $wgReadOnly === null ) {
1284                 // Set $wgReadOnly for faster access next time
1285                 if ( is_file( $wgReadOnlyFile ) && filesize( $wgReadOnlyFile ) > 0 ) {
1286                         $wgReadOnly = file_get_contents( $wgReadOnlyFile );
1287                 } else {
1288                         $wgReadOnly = false;
1289                 }
1290         }
1291
1292         return $wgReadOnly;
1293 }
1294
1295 /**
1296  * Return a Language object from $langcode
1297  *
1298  * @param $langcode Mixed: either:
1299  *                  - a Language object
1300  *                  - code of the language to get the message for, if it is
1301  *                    a valid code create a language for that language, if
1302  *                    it is a string but not a valid code then make a basic
1303  *                    language object
1304  *                  - a boolean: if it's false then use the global object for
1305  *                    the current user's language (as a fallback for the old parameter
1306  *                    functionality), or if it is true then use global object
1307  *                    for the wiki's content language.
1308  * @return Language object
1309  */
1310 function wfGetLangObj( $langcode = false ) {
1311         # Identify which language to get or create a language object for.
1312         # Using is_object here due to Stub objects.
1313         if ( is_object( $langcode ) ) {
1314                 # Great, we already have the object (hopefully)!
1315                 return $langcode;
1316         }
1317
1318         global $wgContLang, $wgLanguageCode;
1319         if ( $langcode === true || $langcode === $wgLanguageCode ) {
1320                 # $langcode is the language code of the wikis content language object.
1321                 # or it is a boolean and value is true
1322                 return $wgContLang;
1323         }
1324
1325         global $wgLang;
1326         if ( $langcode === false || $langcode === $wgLang->getCode() ) {
1327                 # $langcode is the language code of user language object.
1328                 # or it was a boolean and value is false
1329                 return $wgLang;
1330         }
1331
1332         $validCodes = array_keys( Language::fetchLanguageNames() );
1333         if ( in_array( $langcode, $validCodes ) ) {
1334                 # $langcode corresponds to a valid language.
1335                 return Language::factory( $langcode );
1336         }
1337
1338         # $langcode is a string, but not a valid language code; use content language.
1339         wfDebug( "Invalid language code passed to wfGetLangObj, falling back to content language.\n" );
1340         return $wgContLang;
1341 }
1342
1343 /**
1344  * Old function when $wgBetterDirectionality existed
1345  * All usage removed, wfUILang can be removed in near future
1346  *
1347  * @deprecated since 1.18
1348  * @return Language
1349  */
1350 function wfUILang() {
1351         wfDeprecated( __METHOD__, '1.18' );
1352         global $wgLang;
1353         return $wgLang;
1354 }
1355
1356 /**
1357  * This is the function for getting translated interface messages.
1358  *
1359  * @see Message class for documentation how to use them.
1360  * @see https://www.mediawiki.org/wiki/Manual:Messages_API
1361  *
1362  * This function replaces all old wfMsg* functions.
1363  *
1364  * @param $key \string Message key.
1365  * Varargs: normal message parameters.
1366  * @return Message
1367  * @since 1.17
1368  */
1369 function wfMessage( $key /*...*/) {
1370         $params = func_get_args();
1371         array_shift( $params );
1372         if ( isset( $params[0] ) && is_array( $params[0] ) ) {
1373                 $params = $params[0];
1374         }
1375         return new Message( $key, $params );
1376 }
1377
1378 /**
1379  * This function accepts multiple message keys and returns a message instance
1380  * for the first message which is non-empty. If all messages are empty then an
1381  * instance of the first message key is returned.
1382  * @param varargs: message keys
1383  * @return Message
1384  * @since 1.18
1385  */
1386 function wfMessageFallback( /*...*/ ) {
1387         $args = func_get_args();
1388         return call_user_func_array( 'Message::newFallbackSequence', $args );
1389 }
1390
1391 /**
1392  * Get a message from anywhere, for the current user language.
1393  *
1394  * Use wfMsgForContent() instead if the message should NOT
1395  * change depending on the user preferences.
1396  *
1397  * @deprecated since 1.18
1398  *
1399  * @param string $key lookup key for the message, usually
1400  *    defined in languages/Language.php
1401  *
1402  * Parameters to the message, which can be used to insert variable text into
1403  * it, can be passed to this function in the following formats:
1404  * - One per argument, starting at the second parameter
1405  * - As an array in the second parameter
1406  * These are not shown in the function definition.
1407  *
1408  * @return String
1409  */
1410 function wfMsg( $key ) {
1411         wfDeprecated( __METHOD__, '1.21' );
1412
1413         $args = func_get_args();
1414         array_shift( $args );
1415         return wfMsgReal( $key, $args );
1416 }
1417
1418 /**
1419  * Same as above except doesn't transform the message
1420  *
1421  * @deprecated since 1.18
1422  *
1423  * @param $key String
1424  * @return String
1425  */
1426 function wfMsgNoTrans( $key ) {
1427         wfDeprecated( __METHOD__, '1.21' );
1428
1429         $args = func_get_args();
1430         array_shift( $args );
1431         return wfMsgReal( $key, $args, true, false, false );
1432 }
1433
1434 /**
1435  * Get a message from anywhere, for the current global language
1436  * set with $wgLanguageCode.
1437  *
1438  * Use this if the message should NOT change dependent on the
1439  * language set in the user's preferences. This is the case for
1440  * most text written into logs, as well as link targets (such as
1441  * the name of the copyright policy page). Link titles, on the
1442  * other hand, should be shown in the UI language.
1443  *
1444  * Note that MediaWiki allows users to change the user interface
1445  * language in their preferences, but a single installation
1446  * typically only contains content in one language.
1447  *
1448  * Be wary of this distinction: If you use wfMsg() where you should
1449  * use wfMsgForContent(), a user of the software may have to
1450  * customize potentially hundreds of messages in
1451  * order to, e.g., fix a link in every possible language.
1452  *
1453  * @deprecated since 1.18
1454  *
1455  * @param string $key lookup key for the message, usually
1456  *     defined in languages/Language.php
1457  * @return String
1458  */
1459 function wfMsgForContent( $key ) {
1460         wfDeprecated( __METHOD__, '1.21' );
1461
1462         global $wgForceUIMsgAsContentMsg;
1463         $args = func_get_args();
1464         array_shift( $args );
1465         $forcontent = true;
1466         if ( is_array( $wgForceUIMsgAsContentMsg )
1467                 && in_array( $key, $wgForceUIMsgAsContentMsg )
1468         ) {
1469                 $forcontent = false;
1470         }
1471         return wfMsgReal( $key, $args, true, $forcontent );
1472 }
1473
1474 /**
1475  * Same as above except doesn't transform the message
1476  *
1477  * @deprecated since 1.18
1478  *
1479  * @param $key String
1480  * @return String
1481  */
1482 function wfMsgForContentNoTrans( $key ) {
1483         wfDeprecated( __METHOD__, '1.21' );
1484
1485         global $wgForceUIMsgAsContentMsg;
1486         $args = func_get_args();
1487         array_shift( $args );
1488         $forcontent = true;
1489         if ( is_array( $wgForceUIMsgAsContentMsg )
1490                 && in_array( $key, $wgForceUIMsgAsContentMsg )
1491         ) {
1492                 $forcontent = false;
1493         }
1494         return wfMsgReal( $key, $args, true, $forcontent, false );
1495 }
1496
1497 /**
1498  * Really get a message
1499  *
1500  * @deprecated since 1.18
1501  *
1502  * @param string $key key to get.
1503  * @param $args
1504  * @param $useDB Boolean
1505  * @param $forContent Mixed: Language code, or false for user lang, true for content lang.
1506  * @param $transform Boolean: Whether or not to transform the message.
1507  * @return String: the requested message.
1508  */
1509 function wfMsgReal( $key, $args, $useDB = true, $forContent = false, $transform = true ) {
1510         wfDeprecated( __METHOD__, '1.21' );
1511
1512         wfProfileIn( __METHOD__ );
1513         $message = wfMsgGetKey( $key, $useDB, $forContent, $transform );
1514         $message = wfMsgReplaceArgs( $message, $args );
1515         wfProfileOut( __METHOD__ );
1516         return $message;
1517 }
1518
1519 /**
1520  * Fetch a message string value, but don't replace any keys yet.
1521  *
1522  * @deprecated since 1.18
1523  *
1524  * @param $key String
1525  * @param $useDB Bool
1526  * @param string $langCode Code of the language to get the message for, or
1527  *                  behaves as a content language switch if it is a boolean.
1528  * @param $transform Boolean: whether to parse magic words, etc.
1529  * @return string
1530  */
1531 function wfMsgGetKey( $key, $useDB = true, $langCode = false, $transform = true ) {
1532         wfDeprecated( __METHOD__, '1.21' );
1533
1534         wfRunHooks( 'NormalizeMessageKey', array( &$key, &$useDB, &$langCode, &$transform ) );
1535
1536         $cache = MessageCache::singleton();
1537         $message = $cache->get( $key, $useDB, $langCode );
1538         if ( $message === false ) {
1539                 $message = '&lt;' . htmlspecialchars( $key ) . '&gt;';
1540         } elseif ( $transform ) {
1541                 $message = $cache->transform( $message );
1542         }
1543         return $message;
1544 }
1545
1546 /**
1547  * Replace message parameter keys on the given formatted output.
1548  *
1549  * @param $message String
1550  * @param $args Array
1551  * @return string
1552  * @private
1553  */
1554 function wfMsgReplaceArgs( $message, $args ) {
1555         # Fix windows line-endings
1556         # Some messages are split with explode("\n", $msg)
1557         $message = str_replace( "\r", '', $message );
1558
1559         // Replace arguments
1560         if ( count( $args ) ) {
1561                 if ( is_array( $args[0] ) ) {
1562                         $args = array_values( $args[0] );
1563                 }
1564                 $replacementKeys = array();
1565                 foreach ( $args as $n => $param ) {
1566                         $replacementKeys['$' . ( $n + 1 )] = $param;
1567                 }
1568                 $message = strtr( $message, $replacementKeys );
1569         }
1570
1571         return $message;
1572 }
1573
1574 /**
1575  * Return an HTML-escaped version of a message.
1576  * Parameter replacements, if any, are done *after* the HTML-escaping,
1577  * so parameters may contain HTML (eg links or form controls). Be sure
1578  * to pre-escape them if you really do want plaintext, or just wrap
1579  * the whole thing in htmlspecialchars().
1580  *
1581  * @deprecated since 1.18
1582  *
1583  * @param $key String
1584  * @param string ... parameters
1585  * @return string
1586  */
1587 function wfMsgHtml( $key ) {
1588         wfDeprecated( __METHOD__, '1.21' );
1589
1590         $args = func_get_args();
1591         array_shift( $args );
1592         return wfMsgReplaceArgs( htmlspecialchars( wfMsgGetKey( $key ) ), $args );
1593 }
1594
1595 /**
1596  * Return an HTML version of message
1597  * Parameter replacements, if any, are done *after* parsing the wiki-text message,
1598  * so parameters may contain HTML (eg links or form controls). Be sure
1599  * to pre-escape them if you really do want plaintext, or just wrap
1600  * the whole thing in htmlspecialchars().
1601  *
1602  * @deprecated since 1.18
1603  *
1604  * @param $key String
1605  * @param string ... parameters
1606  * @return string
1607  */
1608 function wfMsgWikiHtml( $key ) {
1609         wfDeprecated( __METHOD__, '1.21' );
1610
1611         $args = func_get_args();
1612         array_shift( $args );
1613         return wfMsgReplaceArgs(
1614                 MessageCache::singleton()->parse( wfMsgGetKey( $key ), null,
1615                 /* can't be set to false */ true, /* interface */ true )->getText(),
1616                 $args );
1617 }
1618
1619 /**
1620  * Returns message in the requested format
1621  *
1622  * @deprecated since 1.18
1623  *
1624  * @param string $key key of the message
1625  * @param array $options processing rules. Can take the following options:
1626  *   <i>parse</i>: parses wikitext to HTML
1627  *   <i>parseinline</i>: parses wikitext to HTML and removes the surrounding
1628  *       p's added by parser or tidy
1629  *   <i>escape</i>: filters message through htmlspecialchars
1630  *   <i>escapenoentities</i>: same, but allows entity references like &#160; through
1631  *   <i>replaceafter</i>: parameters are substituted after parsing or escaping
1632  *   <i>parsemag</i>: transform the message using magic phrases
1633  *   <i>content</i>: fetch message for content language instead of interface
1634  * Also can accept a single associative argument, of the form 'language' => 'xx':
1635  *   <i>language</i>: Language object or language code to fetch message for
1636  *       (overridden by <i>content</i>).
1637  * Behavior for conflicting options (e.g., parse+parseinline) is undefined.
1638  *
1639  * @return String
1640  */
1641 function wfMsgExt( $key, $options ) {
1642         wfDeprecated( __METHOD__, '1.21' );
1643
1644         $args = func_get_args();
1645         array_shift( $args );
1646         array_shift( $args );
1647         $options = (array)$options;
1648
1649         foreach ( $options as $arrayKey => $option ) {
1650                 if ( !preg_match( '/^[0-9]+|language$/', $arrayKey ) ) {
1651                         # An unknown index, neither numeric nor "language"
1652                         wfWarn( "wfMsgExt called with incorrect parameter key $arrayKey", 1, E_USER_WARNING );
1653                 } elseif ( preg_match( '/^[0-9]+$/', $arrayKey ) && !in_array( $option,
1654                 array( 'parse', 'parseinline', 'escape', 'escapenoentities',
1655                 'replaceafter', 'parsemag', 'content' ) ) ) {
1656                         # A numeric index with unknown value
1657                         wfWarn( "wfMsgExt called with incorrect parameter $option", 1, E_USER_WARNING );
1658                 }
1659         }
1660
1661         if ( in_array( 'content', $options, true ) ) {
1662                 $forContent = true;
1663                 $langCode = true;
1664                 $langCodeObj = null;
1665         } elseif ( array_key_exists( 'language', $options ) ) {
1666                 $forContent = false;
1667                 $langCode = wfGetLangObj( $options['language'] );
1668                 $langCodeObj = $langCode;
1669         } else {
1670                 $forContent = false;
1671                 $langCode = false;
1672                 $langCodeObj = null;
1673         }
1674
1675         $string = wfMsgGetKey( $key, /*DB*/true, $langCode, /*Transform*/false );
1676
1677         if ( !in_array( 'replaceafter', $options, true ) ) {
1678                 $string = wfMsgReplaceArgs( $string, $args );
1679         }
1680
1681         $messageCache = MessageCache::singleton();
1682         $parseInline = in_array( 'parseinline', $options, true );
1683         if ( in_array( 'parse', $options, true ) || $parseInline ) {
1684                 $string = $messageCache->parse( $string, null, true, !$forContent, $langCodeObj );
1685                 if ( $string instanceof ParserOutput ) {
1686                         $string = $string->getText();
1687                 }
1688
1689                 if ( $parseInline ) {
1690                         $m = array();
1691                         if ( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $string, $m ) ) {
1692                                 $string = $m[1];
1693                         }
1694                 }
1695         } elseif ( in_array( 'parsemag', $options, true ) ) {
1696                 $string = $messageCache->transform( $string,
1697                                 !$forContent, $langCodeObj );
1698         }
1699
1700         if ( in_array( 'escape', $options, true ) ) {
1701                 $string = htmlspecialchars ( $string );
1702         } elseif ( in_array( 'escapenoentities', $options, true ) ) {
1703                 $string = Sanitizer::escapeHtmlAllowEntities( $string );
1704         }
1705
1706         if ( in_array( 'replaceafter', $options, true ) ) {
1707                 $string = wfMsgReplaceArgs( $string, $args );
1708         }
1709
1710         return $string;
1711 }
1712
1713 /**
1714  * Since wfMsg() and co suck, they don't return false if the message key they
1715  * looked up didn't exist but instead the key wrapped in <>'s, this function checks for the
1716  * nonexistence of messages by checking the MessageCache::get() result directly.
1717  *
1718  * @deprecated since 1.18. Use Message::isDisabled().
1719  *
1720  * @param $key      String: the message key looked up
1721  * @return Boolean True if the message *doesn't* exist.
1722  */
1723 function wfEmptyMsg( $key ) {
1724         wfDeprecated( __METHOD__, '1.21' );
1725
1726         return MessageCache::singleton()->get( $key, /*useDB*/true, /*content*/false ) === false;
1727 }
1728
1729 /**
1730  * Throw a debugging exception. This function previously once exited the process,
1731  * but now throws an exception instead, with similar results.
1732  *
1733  * @deprecated since 1.22; just throw an MWException yourself
1734  * @param string $msg message shown when dying.
1735  * @throws MWException
1736  */
1737 function wfDebugDieBacktrace( $msg = '' ) {
1738         wfDeprecated( __FUNCTION__, '1.22' );
1739         throw new MWException( $msg );
1740 }
1741
1742 /**
1743  * Fetch server name for use in error reporting etc.
1744  * Use real server name if available, so we know which machine
1745  * in a server farm generated the current page.
1746  *
1747  * @return string
1748  */
1749 function wfHostname() {
1750         static $host;
1751         if ( is_null( $host ) ) {
1752
1753                 # Hostname overriding
1754                 global $wgOverrideHostname;
1755                 if ( $wgOverrideHostname !== false ) {
1756                         # Set static and skip any detection
1757                         $host = $wgOverrideHostname;
1758                         return $host;
1759                 }
1760
1761                 if ( function_exists( 'posix_uname' ) ) {
1762                         // This function not present on Windows
1763                         $uname = posix_uname();
1764                 } else {
1765                         $uname = false;
1766                 }
1767                 if ( is_array( $uname ) && isset( $uname['nodename'] ) ) {
1768                         $host = $uname['nodename'];
1769                 } elseif ( getenv( 'COMPUTERNAME' ) ) {
1770                         # Windows computer name
1771                         $host = getenv( 'COMPUTERNAME' );
1772                 } else {
1773                         # This may be a virtual server.
1774                         $host = $_SERVER['SERVER_NAME'];
1775                 }
1776         }
1777         return $host;
1778 }
1779
1780 /**
1781  * Returns a HTML comment with the elapsed time since request.
1782  * This method has no side effects.
1783  *
1784  * @return string
1785  */
1786 function wfReportTime() {
1787         global $wgRequestTime, $wgShowHostnames;
1788
1789         $elapsed = microtime( true ) - $wgRequestTime;
1790
1791         return $wgShowHostnames
1792                 ? sprintf( '<!-- Served by %s in %01.3f secs. -->', wfHostname(), $elapsed )
1793                 : sprintf( '<!-- Served in %01.3f secs. -->', $elapsed );
1794 }
1795
1796 /**
1797  * Safety wrapper for debug_backtrace().
1798  *
1799  * With Zend Optimizer 3.2.0 loaded, this causes segfaults under somewhat
1800  * murky circumstances, which may be triggered in part by stub objects
1801  * or other fancy talking'.
1802  *
1803  * Will return an empty array if Zend Optimizer is detected or if
1804  * debug_backtrace is disabled, otherwise the output from
1805  * debug_backtrace() (trimmed).
1806  *
1807  * @param int $limit This parameter can be used to limit the number of stack frames returned
1808  *
1809  * @return array of backtrace information
1810  */
1811 function wfDebugBacktrace( $limit = 0 ) {
1812         static $disabled = null;
1813
1814         if ( extension_loaded( 'Zend Optimizer' ) ) {
1815                 wfDebug( "Zend Optimizer detected; skipping debug_backtrace for safety.\n" );
1816                 return array();
1817         }
1818
1819         if ( is_null( $disabled ) ) {
1820                 $disabled = false;
1821                 $functions = explode( ',', ini_get( 'disable_functions' ) );
1822                 $functions = array_map( 'trim', $functions );
1823                 $functions = array_map( 'strtolower', $functions );
1824                 if ( in_array( 'debug_backtrace', $functions ) ) {
1825                         wfDebug( "debug_backtrace is in disabled_functions\n" );
1826                         $disabled = true;
1827                 }
1828         }
1829         if ( $disabled ) {
1830                 return array();
1831         }
1832
1833         if ( $limit && version_compare( PHP_VERSION, '5.4.0', '>=' ) ) {
1834                 return array_slice( debug_backtrace( DEBUG_BACKTRACE_PROVIDE_OBJECT, $limit + 1 ), 1 );
1835         } else {
1836                 return array_slice( debug_backtrace(), 1 );
1837         }
1838 }
1839
1840 /**
1841  * Get a debug backtrace as a string
1842  *
1843  * @return string
1844  */
1845 function wfBacktrace() {
1846         global $wgCommandLineMode;
1847
1848         if ( $wgCommandLineMode ) {
1849                 $msg = '';
1850         } else {
1851                 $msg = "<ul>\n";
1852         }
1853         $backtrace = wfDebugBacktrace();
1854         foreach ( $backtrace as $call ) {
1855                 if ( isset( $call['file'] ) ) {
1856                         $f = explode( DIRECTORY_SEPARATOR, $call['file'] );
1857                         $file = $f[count( $f ) - 1];
1858                 } else {
1859                         $file = '-';
1860                 }
1861                 if ( isset( $call['line'] ) ) {
1862                         $line = $call['line'];
1863                 } else {
1864                         $line = '-';
1865                 }
1866                 if ( $wgCommandLineMode ) {
1867                         $msg .= "$file line $line calls ";
1868                 } else {
1869                         $msg .= '<li>' . $file . ' line ' . $line . ' calls ';
1870                 }
1871                 if ( !empty( $call['class'] ) ) {
1872                         $msg .= $call['class'] . $call['type'];
1873                 }
1874                 $msg .= $call['function'] . '()';
1875
1876                 if ( $wgCommandLineMode ) {
1877                         $msg .= "\n";
1878                 } else {
1879                         $msg .= "</li>\n";
1880                 }
1881         }
1882         if ( $wgCommandLineMode ) {
1883                 $msg .= "\n";
1884         } else {
1885                 $msg .= "</ul>\n";
1886         }
1887
1888         return $msg;
1889 }
1890
1891 /**
1892  * Get the name of the function which called this function
1893  * wfGetCaller( 1 ) is the function with the wfGetCaller() call (ie. __FUNCTION__)
1894  * wfGetCaller( 2 ) [default] is the caller of the function running wfGetCaller()
1895  * wfGetCaller( 3 ) is the parent of that.
1896  *
1897  * @param $level Int
1898  * @return string
1899  */
1900 function wfGetCaller( $level = 2 ) {
1901         $backtrace = wfDebugBacktrace( $level + 1 );
1902         if ( isset( $backtrace[$level] ) ) {
1903                 return wfFormatStackFrame( $backtrace[$level] );
1904         } else {
1905                 return 'unknown';
1906         }
1907 }
1908
1909 /**
1910  * Return a string consisting of callers in the stack. Useful sometimes
1911  * for profiling specific points.
1912  *
1913  * @param int $limit The maximum depth of the stack frame to return, or false for
1914  *               the entire stack.
1915  * @return String
1916  */
1917 function wfGetAllCallers( $limit = 3 ) {
1918         $trace = array_reverse( wfDebugBacktrace() );
1919         if ( !$limit || $limit > count( $trace ) - 1 ) {
1920                 $limit = count( $trace ) - 1;
1921         }
1922         $trace = array_slice( $trace, -$limit - 1, $limit );
1923         return implode( '/', array_map( 'wfFormatStackFrame', $trace ) );
1924 }
1925
1926 /**
1927  * Return a string representation of frame
1928  *
1929  * @param $frame Array
1930  * @return string
1931  */
1932 function wfFormatStackFrame( $frame ) {
1933         return isset( $frame['class'] ) ?
1934                 $frame['class'] . '::' . $frame['function'] :
1935                 $frame['function'];
1936 }
1937
1938 /* Some generic result counters, pulled out of SearchEngine */
1939
1940 /**
1941  * @todo document
1942  *
1943  * @param $offset Int
1944  * @param $limit Int
1945  * @return String
1946  */
1947 function wfShowingResults( $offset, $limit ) {
1948         return wfMessage( 'showingresults' )->numParams( $limit, $offset + 1 )->parse();
1949 }
1950
1951 /**
1952  * Generate (prev x| next x) (20|50|100...) type links for paging
1953  *
1954  * @param $offset String
1955  * @param $limit Integer
1956  * @param $link String
1957  * @param string $query optional URL query parameter string
1958  * @param bool $atend optional param for specified if this is the last page
1959  * @return String
1960  * @deprecated in 1.19; use Language::viewPrevNext() instead
1961  */
1962 function wfViewPrevNext( $offset, $limit, $link, $query = '', $atend = false ) {
1963         wfDeprecated( __METHOD__, '1.19' );
1964
1965         global $wgLang;
1966
1967         $query = wfCgiToArray( $query );
1968
1969         if ( is_object( $link ) ) {
1970                 $title = $link;
1971         } else {
1972                 $title = Title::newFromText( $link );
1973                 if ( is_null( $title ) ) {
1974                         return false;
1975                 }
1976         }
1977
1978         return $wgLang->viewPrevNext( $title, $offset, $limit, $query, $atend );
1979 }
1980
1981 /**
1982  * @todo document
1983  * @todo FIXME: We may want to blacklist some broken browsers
1984  *
1985  * @param $force Bool
1986  * @return bool Whereas client accept gzip compression
1987  */
1988 function wfClientAcceptsGzip( $force = false ) {
1989         static $result = null;
1990         if ( $result === null || $force ) {
1991                 $result = false;
1992                 if ( isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ) {
1993                         # @todo FIXME: We may want to blacklist some broken browsers
1994                         $m = array();
1995                         if ( preg_match(
1996                                         '/\bgzip(?:;(q)=([0-9]+(?:\.[0-9]+)))?\b/',
1997                                         $_SERVER['HTTP_ACCEPT_ENCODING'],
1998                                         $m
1999                                 )
2000                         ) {
2001                                 if ( isset( $m[2] ) && ( $m[1] == 'q' ) && ( $m[2] == 0 ) ) {
2002                                         $result = false;
2003                                         return $result;
2004                                 }
2005                                 wfDebug( "wfClientAcceptsGzip: client accepts gzip.\n" );
2006                                 $result = true;
2007                         }
2008                 }
2009         }
2010         return $result;
2011 }
2012
2013 /**
2014  * Obtain the offset and limit values from the request string;
2015  * used in special pages
2016  *
2017  * @param int $deflimit default limit if none supplied
2018  * @param string $optionname Name of a user preference to check against
2019  * @return array
2020  *
2021  */
2022 function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
2023         global $wgRequest;
2024         return $wgRequest->getLimitOffset( $deflimit, $optionname );
2025 }
2026
2027 /**
2028  * Escapes the given text so that it may be output using addWikiText()
2029  * without any linking, formatting, etc. making its way through. This
2030  * is achieved by substituting certain characters with HTML entities.
2031  * As required by the callers, "<nowiki>" is not used.
2032  *
2033  * @param string $text text to be escaped
2034  * @return String
2035  */
2036 function wfEscapeWikiText( $text ) {
2037         static $repl = null, $repl2 = null;
2038         if ( $repl === null ) {
2039                 $repl = array(
2040                         '"' => '&#34;', '&' => '&#38;', "'" => '&#39;', '<' => '&#60;',
2041                         '=' => '&#61;', '>' => '&#62;', '[' => '&#91;', ']' => '&#93;',
2042                         '{' => '&#123;', '|' => '&#124;', '}' => '&#125;', ';' => '&#59;',
2043                         "\n#" => "\n&#35;", "\r#" => "\r&#35;",
2044                         "\n*" => "\n&#42;", "\r*" => "\r&#42;",
2045                         "\n:" => "\n&#58;", "\r:" => "\r&#58;",
2046                         "\n " => "\n&#32;", "\r " => "\r&#32;",
2047                         "\n\n" => "\n&#10;", "\r\n" => "&#13;\n",
2048                         "\n\r" => "\n&#13;", "\r\r" => "\r&#13;",
2049                         "\n\t" => "\n&#9;", "\r\t" => "\r&#9;", // "\n\t\n" is treated like "\n\n"
2050                         "\n----" => "\n&#45;---", "\r----" => "\r&#45;---",
2051                         '__' => '_&#95;', '://' => '&#58;//',
2052                 );
2053
2054                 // We have to catch everything "\s" matches in PCRE
2055                 foreach ( array( 'ISBN', 'RFC', 'PMID' ) as $magic ) {
2056                         $repl["$magic "] = "$magic&#32;";
2057                         $repl["$magic\t"] = "$magic&#9;";
2058                         $repl["$magic\r"] = "$magic&#13;";
2059                         $repl["$magic\n"] = "$magic&#10;";
2060                         $repl["$magic\f"] = "$magic&#12;";
2061                 }
2062
2063                 // And handle protocols that don't use "://"
2064                 global $wgUrlProtocols;
2065                 $repl2 = array();
2066                 foreach ( $wgUrlProtocols as $prot ) {
2067                         if ( substr( $prot, -1 ) === ':' ) {
2068                                 $repl2[] = preg_quote( substr( $prot, 0, -1 ), '/' );
2069                         }
2070                 }
2071                 $repl2 = $repl2 ? '/\b(' . join( '|', $repl2 ) . '):/i' : '/^(?!)/';
2072         }
2073         $text = substr( strtr( "\n$text", $repl ), 1 );
2074         $text = preg_replace( $repl2, '$1&#58;', $text );
2075         return $text;
2076 }
2077
2078 /**
2079  * Get the current unix timestamp with microseconds.  Useful for profiling
2080  * @deprecated since 1.22; call microtime() directly
2081  * @return Float
2082  */
2083 function wfTime() {
2084         wfDeprecated( __FUNCTION__, '1.22' );
2085         return microtime( true );
2086 }
2087
2088 /**
2089  * Sets dest to source and returns the original value of dest
2090  * If source is NULL, it just returns the value, it doesn't set the variable
2091  * If force is true, it will set the value even if source is NULL
2092  *
2093  * @param $dest Mixed
2094  * @param $source Mixed
2095  * @param $force Bool
2096  * @return Mixed
2097  */
2098 function wfSetVar( &$dest, $source, $force = false ) {
2099         $temp = $dest;
2100         if ( !is_null( $source ) || $force ) {
2101                 $dest = $source;
2102         }
2103         return $temp;
2104 }
2105
2106 /**
2107  * As for wfSetVar except setting a bit
2108  *
2109  * @param $dest Int
2110  * @param $bit Int
2111  * @param $state Bool
2112  *
2113  * @return bool
2114  */
2115 function wfSetBit( &$dest, $bit, $state = true ) {
2116         $temp = (bool)( $dest & $bit );
2117         if ( !is_null( $state ) ) {
2118                 if ( $state ) {
2119                         $dest |= $bit;
2120                 } else {
2121                         $dest &= ~$bit;
2122                 }
2123         }
2124         return $temp;
2125 }
2126
2127 /**
2128  * A wrapper around the PHP function var_export().
2129  * Either print it or add it to the regular output ($wgOut).
2130  *
2131  * @param $var mixed A PHP variable to dump.
2132  */
2133 function wfVarDump( $var ) {
2134         global $wgOut;
2135         $s = str_replace( "\n", "<br />\n", var_export( $var, true ) . "\n" );
2136         if ( headers_sent() || !isset( $wgOut ) || !is_object( $wgOut ) ) {
2137                 print $s;
2138         } else {
2139                 $wgOut->addHTML( $s );
2140         }
2141 }
2142
2143 /**
2144  * Provide a simple HTTP error.
2145  *
2146  * @param $code Int|String
2147  * @param $label String
2148  * @param $desc String
2149  */
2150 function wfHttpError( $code, $label, $desc ) {
2151         global $wgOut;
2152         $wgOut->disable();
2153         header( "HTTP/1.0 $code $label" );
2154         header( "Status: $code $label" );
2155         $wgOut->sendCacheControl();
2156
2157         header( 'Content-type: text/html; charset=utf-8' );
2158         print "<!doctype html>" .
2159                 '<html><head><title>' .
2160                 htmlspecialchars( $label ) .
2161                 '</title></head><body><h1>' .
2162                 htmlspecialchars( $label ) .
2163                 '</h1><p>' .
2164                 nl2br( htmlspecialchars( $desc ) ) .
2165                 "</p></body></html>\n";
2166 }
2167
2168 /**
2169  * Clear away any user-level output buffers, discarding contents.
2170  *
2171  * Suitable for 'starting afresh', for instance when streaming
2172  * relatively large amounts of data without buffering, or wanting to
2173  * output image files without ob_gzhandler's compression.
2174  *
2175  * The optional $resetGzipEncoding parameter controls suppression of
2176  * the Content-Encoding header sent by ob_gzhandler; by default it
2177  * is left. See comments for wfClearOutputBuffers() for why it would
2178  * be used.
2179  *
2180  * Note that some PHP configuration options may add output buffer
2181  * layers which cannot be removed; these are left in place.
2182  *
2183  * @param $resetGzipEncoding Bool
2184  */
2185 function wfResetOutputBuffers( $resetGzipEncoding = true ) {
2186         if ( $resetGzipEncoding ) {
2187                 // Suppress Content-Encoding and Content-Length
2188                 // headers from 1.10+s wfOutputHandler
2189                 global $wgDisableOutputCompression;
2190                 $wgDisableOutputCompression = true;
2191         }
2192         while ( $status = ob_get_status() ) {
2193                 if ( $status['type'] == 0 /* PHP_OUTPUT_HANDLER_INTERNAL */ ) {
2194                         // Probably from zlib.output_compression or other
2195                         // PHP-internal setting which can't be removed.
2196                         //
2197                         // Give up, and hope the result doesn't break
2198                         // output behavior.
2199                         break;
2200                 }
2201                 if ( !ob_end_clean() ) {
2202                         // Could not remove output buffer handler; abort now
2203                         // to avoid getting in some kind of infinite loop.
2204                         break;
2205                 }
2206                 if ( $resetGzipEncoding ) {
2207                         if ( $status['name'] == 'ob_gzhandler' ) {
2208                                 // Reset the 'Content-Encoding' field set by this handler
2209                                 // so we can start fresh.
2210                                 header_remove( 'Content-Encoding' );
2211                                 break;
2212                         }
2213                 }
2214         }
2215 }
2216
2217 /**
2218  * More legible than passing a 'false' parameter to wfResetOutputBuffers():
2219  *
2220  * Clear away output buffers, but keep the Content-Encoding header
2221  * produced by ob_gzhandler, if any.
2222  *
2223  * This should be used for HTTP 304 responses, where you need to
2224  * preserve the Content-Encoding header of the real result, but
2225  * also need to suppress the output of ob_gzhandler to keep to spec
2226  * and avoid breaking Firefox in rare cases where the headers and
2227  * body are broken over two packets.
2228  */
2229 function wfClearOutputBuffers() {
2230         wfResetOutputBuffers( false );
2231 }
2232
2233 /**
2234  * Converts an Accept-* header into an array mapping string values to quality
2235  * factors
2236  *
2237  * @param $accept String
2238  * @param string $def default
2239  * @return Array
2240  */
2241 function wfAcceptToPrefs( $accept, $def = '*/*' ) {
2242         # No arg means accept anything (per HTTP spec)
2243         if ( !$accept ) {
2244                 return array( $def => 1.0 );
2245         }
2246
2247         $prefs = array();
2248
2249         $parts = explode( ',', $accept );
2250
2251         foreach ( $parts as $part ) {
2252                 # @todo FIXME: Doesn't deal with params like 'text/html; level=1'
2253                 $values = explode( ';', trim( $part ) );
2254                 $match = array();
2255                 if ( count( $values ) == 1 ) {
2256                         $prefs[$values[0]] = 1.0;
2257                 } elseif ( preg_match( '/q\s*=\s*(\d*\.\d+)/', $values[1], $match ) ) {
2258                         $prefs[$values[0]] = floatval( $match[1] );
2259                 }
2260         }
2261
2262         return $prefs;
2263 }
2264
2265 /**
2266  * Checks if a given MIME type matches any of the keys in the given
2267  * array. Basic wildcards are accepted in the array keys.
2268  *
2269  * Returns the matching MIME type (or wildcard) if a match, otherwise
2270  * NULL if no match.
2271  *
2272  * @param $type String
2273  * @param $avail Array
2274  * @return string
2275  * @private
2276  */
2277 function mimeTypeMatch( $type, $avail ) {
2278         if ( array_key_exists( $type, $avail ) ) {
2279                 return $type;
2280         } else {
2281                 $parts = explode( '/', $type );
2282                 if ( array_key_exists( $parts[0] . '/*', $avail ) ) {
2283                         return $parts[0] . '/*';
2284                 } elseif ( array_key_exists( '*/*', $avail ) ) {
2285                         return '*/*';
2286                 } else {
2287                         return null;
2288                 }
2289         }
2290 }
2291
2292 /**
2293  * Returns the 'best' match between a client's requested internet media types
2294  * and the server's list of available types. Each list should be an associative
2295  * array of type to preference (preference is a float between 0.0 and 1.0).
2296  * Wildcards in the types are acceptable.
2297  *
2298  * @param array $cprefs client's acceptable type list
2299  * @param array $sprefs server's offered types
2300  * @return string
2301  *
2302  * @todo FIXME: Doesn't handle params like 'text/plain; charset=UTF-8'
2303  * XXX: generalize to negotiate other stuff
2304  */
2305 function wfNegotiateType( $cprefs, $sprefs ) {
2306         $combine = array();
2307
2308         foreach ( array_keys( $sprefs ) as $type ) {
2309                 $parts = explode( '/', $type );
2310                 if ( $parts[1] != '*' ) {
2311                         $ckey = mimeTypeMatch( $type, $cprefs );
2312                         if ( $ckey ) {
2313                                 $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
2314                         }
2315                 }
2316         }
2317
2318         foreach ( array_keys( $cprefs ) as $type ) {
2319                 $parts = explode( '/', $type );
2320                 if ( $parts[1] != '*' && !array_key_exists( $type, $sprefs ) ) {
2321                         $skey = mimeTypeMatch( $type, $sprefs );
2322                         if ( $skey ) {
2323                                 $combine[$type] = $sprefs[$skey] * $cprefs[$type];
2324                         }
2325                 }
2326         }
2327
2328         $bestq = 0;
2329         $besttype = null;
2330
2331         foreach ( array_keys( $combine ) as $type ) {
2332                 if ( $combine[$type] > $bestq ) {
2333                         $besttype = $type;
2334                         $bestq = $combine[$type];
2335                 }
2336         }
2337
2338         return $besttype;
2339 }
2340
2341 /**
2342  * Reference-counted warning suppression
2343  *
2344  * @param $end Bool
2345  */
2346 function wfSuppressWarnings( $end = false ) {
2347         static $suppressCount = 0;
2348         static $originalLevel = false;
2349
2350         if ( $end ) {
2351                 if ( $suppressCount ) {
2352                         --$suppressCount;
2353                         if ( !$suppressCount ) {
2354                                 error_reporting( $originalLevel );
2355                         }
2356                 }
2357         } else {
2358                 if ( !$suppressCount ) {
2359                         $originalLevel = error_reporting( E_ALL & ~(
2360                                 E_WARNING |
2361                                 E_NOTICE |
2362                                 E_USER_WARNING |
2363                                 E_USER_NOTICE |
2364                                 E_DEPRECATED |
2365                                 E_USER_DEPRECATED |
2366                                 E_STRICT
2367                         ) );
2368                 }
2369                 ++$suppressCount;
2370         }
2371 }
2372
2373 /**
2374  * Restore error level to previous value
2375  */
2376 function wfRestoreWarnings() {
2377         wfSuppressWarnings( true );
2378 }
2379
2380 # Autodetect, convert and provide timestamps of various types
2381
2382 /**
2383  * Unix time - the number of seconds since 1970-01-01 00:00:00 UTC
2384  */
2385 define( 'TS_UNIX', 0 );
2386
2387 /**
2388  * MediaWiki concatenated string timestamp (YYYYMMDDHHMMSS)
2389  */
2390 define( 'TS_MW', 1 );
2391
2392 /**
2393  * MySQL DATETIME (YYYY-MM-DD HH:MM:SS)
2394  */
2395 define( 'TS_DB', 2 );
2396
2397 /**
2398  * RFC 2822 format, for E-mail and HTTP headers
2399  */
2400 define( 'TS_RFC2822', 3 );
2401
2402 /**
2403  * ISO 8601 format with no timezone: 1986-02-09T20:00:00Z
2404  *
2405  * This is used by Special:Export
2406  */
2407 define( 'TS_ISO_8601', 4 );
2408
2409 /**
2410  * An Exif timestamp (YYYY:MM:DD HH:MM:SS)
2411  *
2412  * @see http://exif.org/Exif2-2.PDF The Exif 2.2 spec, see page 28 for the
2413  *       DateTime tag and page 36 for the DateTimeOriginal and
2414  *       DateTimeDigitized tags.
2415  */
2416 define( 'TS_EXIF', 5 );
2417
2418 /**
2419  * Oracle format time.
2420  */
2421 define( 'TS_ORACLE', 6 );
2422
2423 /**
2424  * Postgres format time.
2425  */
2426 define( 'TS_POSTGRES', 7 );
2427
2428 /**
2429  * ISO 8601 basic format with no timezone: 19860209T200000Z.  This is used by ResourceLoader
2430  */
2431 define( 'TS_ISO_8601_BASIC', 9 );
2432
2433 /**
2434  * Get a timestamp string in one of various formats
2435  *
2436  * @param $outputtype Mixed: A timestamp in one of the supported formats, the
2437  *                    function will autodetect which format is supplied and act
2438  *                    accordingly.
2439  * @param $ts Mixed: optional timestamp to convert, default 0 for the current time
2440  * @return Mixed: String / false The same date in the format specified in $outputtype or false
2441  */
2442 function wfTimestamp( $outputtype = TS_UNIX, $ts = 0 ) {
2443         try {
2444                 $timestamp = new MWTimestamp( $ts );
2445                 return $timestamp->getTimestamp( $outputtype );
2446         } catch ( TimestampException $e ) {
2447                 wfDebug( "wfTimestamp() fed bogus time value: TYPE=$outputtype; VALUE=$ts\n" );
2448                 return false;
2449         }
2450 }
2451
2452 /**
2453  * Return a formatted timestamp, or null if input is null.
2454  * For dealing with nullable timestamp columns in the database.
2455  *
2456  * @param $outputtype Integer
2457  * @param $ts String
2458  * @return String
2459  */
2460 function wfTimestampOrNull( $outputtype = TS_UNIX, $ts = null ) {
2461         if ( is_null( $ts ) ) {
2462                 return null;
2463         } else {
2464                 return wfTimestamp( $outputtype, $ts );
2465         }
2466 }
2467
2468 /**
2469  * Convenience function; returns MediaWiki timestamp for the present time.
2470  *
2471  * @return string
2472  */
2473 function wfTimestampNow() {
2474         # return NOW
2475         return wfTimestamp( TS_MW, time() );
2476 }
2477
2478 /**
2479  * Check if the operating system is Windows
2480  *
2481  * @return Bool: true if it's Windows, False otherwise.
2482  */
2483 function wfIsWindows() {
2484         static $isWindows = null;
2485         if ( $isWindows === null ) {
2486                 $isWindows = substr( php_uname(), 0, 7 ) == 'Windows';
2487         }
2488         return $isWindows;
2489 }
2490
2491 /**
2492  * Check if we are running under HHVM
2493  *
2494  * @return Bool
2495  */
2496 function wfIsHHVM() {
2497         return defined( 'HHVM_VERSION' );
2498 }
2499
2500 /**
2501  * Swap two variables
2502  *
2503  * @param $x Mixed
2504  * @param $y Mixed
2505  */
2506 function swap( &$x, &$y ) {
2507         $z = $x;
2508         $x = $y;
2509         $y = $z;
2510 }
2511
2512 /**
2513  * Tries to get the system directory for temporary files. First
2514  * $wgTmpDirectory is checked, and then the TMPDIR, TMP, and TEMP
2515  * environment variables are then checked in sequence, and if none are
2516  * set try sys_get_temp_dir().
2517  *
2518  * NOTE: When possible, use instead the tmpfile() function to create
2519  * temporary files to avoid race conditions on file creation, etc.
2520  *
2521  * @return String
2522  */
2523 function wfTempDir() {
2524         global $wgTmpDirectory;
2525
2526         if ( $wgTmpDirectory !== false ) {
2527                 return $wgTmpDirectory;
2528         }
2529
2530         $tmpDir = array_map( "getenv", array( 'TMPDIR', 'TMP', 'TEMP' ) );
2531
2532         foreach ( $tmpDir as $tmp ) {
2533                 if ( $tmp && file_exists( $tmp ) && is_dir( $tmp ) && is_writable( $tmp ) ) {
2534                         return $tmp;
2535                 }
2536         }
2537         return sys_get_temp_dir();
2538 }
2539
2540 /**
2541  * Make directory, and make all parent directories if they don't exist
2542  *
2543  * @param string $dir full path to directory to create
2544  * @param $mode Integer: chmod value to use, default is $wgDirectoryMode
2545  * @param string $caller optional caller param for debugging.
2546  * @throws MWException
2547  * @return bool
2548  */
2549 function wfMkdirParents( $dir, $mode = null, $caller = null ) {
2550         global $wgDirectoryMode;
2551
2552         if ( FileBackend::isStoragePath( $dir ) ) { // sanity
2553                 throw new MWException( __FUNCTION__ . " given storage path '$dir'." );
2554         }
2555
2556         if ( !is_null( $caller ) ) {
2557                 wfDebug( "$caller: called wfMkdirParents($dir)\n" );
2558         }
2559
2560         if ( strval( $dir ) === '' || ( file_exists( $dir ) && is_dir( $dir ) ) ) {
2561                 return true;
2562         }
2563
2564         $dir = str_replace( array( '\\', '/' ), DIRECTORY_SEPARATOR, $dir );
2565
2566         if ( is_null( $mode ) ) {
2567                 $mode = $wgDirectoryMode;
2568         }
2569
2570         // Turn off the normal warning, we're doing our own below
2571         wfSuppressWarnings();
2572         $ok = mkdir( $dir, $mode, true ); // PHP5 <3
2573         wfRestoreWarnings();
2574
2575         if ( !$ok ) {
2576                 //directory may have been created on another request since we last checked
2577                 if ( is_dir( $dir ) ) {
2578                         return true;
2579                 }
2580
2581                 // PHP doesn't report the path in its warning message, so add our own to aid in diagnosis.
2582                 wfLogWarning( sprintf( "failed to mkdir \"%s\" mode 0%o", $dir, $mode ) );
2583         }
2584         return $ok;
2585 }
2586
2587 /**
2588  * Remove a directory and all its content.
2589  * Does not hide error.
2590  */
2591 function wfRecursiveRemoveDir( $dir ) {
2592         wfDebug( __FUNCTION__ . "( $dir )\n" );
2593         // taken from http://de3.php.net/manual/en/function.rmdir.php#98622
2594         if ( is_dir( $dir ) ) {
2595                 $objects = scandir( $dir );
2596                 foreach ( $objects as $object ) {
2597                         if ( $object != "." && $object != ".." ) {
2598                                 if ( filetype( $dir . '/' . $object ) == "dir" ) {
2599                                         wfRecursiveRemoveDir( $dir . '/' . $object );
2600                                 } else {
2601                                         unlink( $dir . '/' . $object );
2602                                 }
2603                         }
2604                 }
2605                 reset( $objects );
2606                 rmdir( $dir );
2607         }
2608 }
2609
2610 /**
2611  * @param $nr Mixed: the number to format
2612  * @param $acc Integer: the number of digits after the decimal point, default 2
2613  * @param $round Boolean: whether or not to round the value, default true
2614  * @return float
2615  */
2616 function wfPercent( $nr, $acc = 2, $round = true ) {
2617         $ret = sprintf( "%.${acc}f", $nr );
2618         return $round ? round( $ret, $acc ) . '%' : "$ret%";
2619 }
2620
2621 /**
2622  * Find out whether or not a mixed variable exists in a string
2623  *
2624  * @deprecated Just use str(i)pos
2625  * @param $needle String
2626  * @param $str String
2627  * @param $insensitive Boolean
2628  * @return Boolean
2629  */
2630 function in_string( $needle, $str, $insensitive = false ) {
2631         wfDeprecated( __METHOD__, '1.21' );
2632         $func = 'strpos';
2633         if ( $insensitive ) {
2634                 $func = 'stripos';
2635         }
2636
2637         return $func( $str, $needle ) !== false;
2638 }
2639
2640 /**
2641  * Safety wrapper around ini_get() for boolean settings.
2642  * The values returned from ini_get() are pre-normalized for settings
2643  * set via php.ini or php_flag/php_admin_flag... but *not*
2644  * for those set via php_value/php_admin_value.
2645  *
2646  * It's fairly common for people to use php_value instead of php_flag,
2647  * which can leave you with an 'off' setting giving a false positive
2648  * for code that just takes the ini_get() return value as a boolean.
2649  *
2650  * To make things extra interesting, setting via php_value accepts
2651  * "true" and "yes" as true, but php.ini and php_flag consider them false. :)
2652  * Unrecognized values go false... again opposite PHP's own coercion
2653  * from string to bool.
2654  *
2655  * Luckily, 'properly' set settings will always come back as '0' or '1',
2656  * so we only have to worry about them and the 'improper' settings.
2657  *
2658  * I frickin' hate PHP... :P
2659  *
2660  * @param $setting String
2661  * @return Bool
2662  */
2663 function wfIniGetBool( $setting ) {
2664         $val = strtolower( ini_get( $setting ) );
2665         // 'on' and 'true' can't have whitespace around them, but '1' can.
2666         return $val == 'on'
2667                 || $val == 'true'
2668                 || $val == 'yes'
2669                 || preg_match( "/^\s*[+-]?0*[1-9]/", $val ); // approx C atoi() function
2670 }
2671
2672 /**
2673  * Windows-compatible version of escapeshellarg()
2674  * Windows doesn't recognise single-quotes in the shell, but the escapeshellarg()
2675  * function puts single quotes in regardless of OS.
2676  *
2677  * Also fixes the locale problems on Linux in PHP 5.2.6+ (bug backported to
2678  * earlier distro releases of PHP)
2679  *
2680  * @param varargs
2681  * @return String
2682  */
2683 function wfEscapeShellArg() {
2684         wfInitShellLocale();
2685
2686         $args = func_get_args();
2687         $first = true;
2688         $retVal = '';
2689         foreach ( $args as $arg ) {
2690                 if ( !$first ) {
2691                         $retVal .= ' ';
2692                 } else {
2693                         $first = false;
2694                 }
2695
2696                 if ( wfIsWindows() ) {
2697                         // Escaping for an MSVC-style command line parser and CMD.EXE
2698                         // @codingStandardsIgnoreStart For long URLs
2699                         // Refs:
2700                         //  * http://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
2701                         //  * http://technet.microsoft.com/en-us/library/cc723564.aspx
2702                         //  * Bug #13518
2703                         //  * CR r63214
2704                         // Double the backslashes before any double quotes. Escape the double quotes.
2705                         // @codingStandardsIgnoreEnd
2706                         $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
2707                         $arg = '';
2708                         $iteration = 0;
2709                         foreach ( $tokens as $token ) {
2710                                 if ( $iteration % 2 == 1 ) {
2711                                         // Delimiter, a double quote preceded by zero or more slashes
2712                                         $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
2713                                 } elseif ( $iteration % 4 == 2 ) {
2714                                         // ^ in $token will be outside quotes, need to be escaped
2715                                         $arg .= str_replace( '^', '^^', $token );
2716                                 } else { // $iteration % 4 == 0
2717                                         // ^ in $token will appear inside double quotes, so leave as is
2718                                         $arg .= $token;
2719                                 }
2720                                 $iteration++;
2721                         }
2722                         // Double the backslashes before the end of the string, because
2723                         // we will soon add a quote
2724                         $m = array();
2725                         if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
2726                                 $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
2727                         }
2728
2729                         // Add surrounding quotes
2730                         $retVal .= '"' . $arg . '"';
2731                 } else {
2732                         $retVal .= escapeshellarg( $arg );
2733                 }
2734         }
2735         return $retVal;
2736 }
2737
2738 /**
2739  * Check if wfShellExec() is effectively disabled via php.ini config
2740  * @return bool|string False or one of (safemode,disabled)
2741  * @since 1.22
2742  */
2743 function wfShellExecDisabled() {
2744         static $disabled = null;
2745         if ( is_null( $disabled ) ) {
2746                 $disabled = false;
2747                 if ( wfIniGetBool( 'safe_mode' ) ) {
2748                         wfDebug( "wfShellExec can't run in safe_mode, PHP's exec functions are too broken.\n" );
2749                         $disabled = 'safemode';
2750                 } else {
2751                         $functions = explode( ',', ini_get( 'disable_functions' ) );
2752                         $functions = array_map( 'trim', $functions );
2753                         $functions = array_map( 'strtolower', $functions );
2754                         if ( in_array( 'proc_open', $functions ) ) {
2755                                 wfDebug( "proc_open is in disabled_functions\n" );
2756                                 $disabled = 'disabled';
2757                         }
2758                 }
2759         }
2760         return $disabled;
2761 }
2762
2763 /**
2764  * Execute a shell command, with time and memory limits mirrored from the PHP
2765  * configuration if supported.
2766  * @param string $cmd Command line, properly escaped for shell.
2767  * @param &$retval null|Mixed optional, will receive the program's exit code.
2768  *                 (non-zero is usually failure). If there is an error from
2769  *                 read, select, or proc_open(), this will be set to -1.
2770  * @param array $environ optional environment variables which should be
2771  *                 added to the executed command environment.
2772  * @param array $limits optional array with limits(filesize, memory, time, walltime)
2773  *                 this overwrites the global wgMaxShell* limits.
2774  * @param array $options Array of options:
2775  *    - duplicateStderr: Set this to true to duplicate stderr to stdout,
2776  *      including errors from limit.sh
2777  *
2778  * @return string collected stdout as a string
2779  */
2780 function wfShellExec( $cmd, &$retval = null, $environ = array(),
2781         $limits = array(), $options = array()
2782 ) {
2783         global $IP, $wgMaxShellMemory, $wgMaxShellFileSize, $wgMaxShellTime,
2784                 $wgMaxShellWallClockTime, $wgShellCgroup;
2785
2786         $disabled = wfShellExecDisabled();
2787         if ( $disabled ) {
2788                 $retval = 1;
2789                 return $disabled == 'safemode' ?
2790                         'Unable to run external programs in safe mode.' :
2791                         'Unable to run external programs, proc_open() is disabled.';
2792         }
2793
2794         $includeStderr = isset( $options['duplicateStderr'] ) && $options['duplicateStderr'];
2795
2796         wfInitShellLocale();
2797
2798         $envcmd = '';
2799         foreach ( $environ as $k => $v ) {
2800                 if ( wfIsWindows() ) {
2801                         /* Surrounding a set in quotes (method used by wfEscapeShellArg) makes the quotes themselves
2802                          * appear in the environment variable, so we must use carat escaping as documented in
2803                          * http://technet.microsoft.com/en-us/library/cc723564.aspx
2804                          * Note however that the quote isn't listed there, but is needed, and the parentheses
2805                          * are listed there but doesn't appear to need it.
2806                          */
2807                         $envcmd .= "set $k=" . preg_replace( '/([&|()<>^"])/', '^\\1', $v ) . '&& ';
2808                 } else {
2809                         /* Assume this is a POSIX shell, thus required to accept variable assignments before the command
2810                          * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_01
2811                          */
2812                         $envcmd .= "$k=" . escapeshellarg( $v ) . ' ';
2813                 }
2814         }
2815         $cmd = $envcmd . $cmd;
2816
2817         $useLogPipe = false;
2818         if ( php_uname( 's' ) == 'Linux' ) {
2819                 $time = intval ( isset( $limits['time'] ) ? $limits['time'] : $wgMaxShellTime );
2820                 if ( isset( $limits['walltime'] ) ) {
2821                         $wallTime = intval( $limits['walltime'] );
2822                 } elseif ( isset( $limits['time'] ) ) {
2823                         $wallTime = $time;
2824                 } else {
2825                         $wallTime = intval( $wgMaxShellWallClockTime );
2826                 }
2827                 $mem = intval ( isset( $limits['memory'] ) ? $limits['memory'] : $wgMaxShellMemory );
2828                 $filesize = intval ( isset( $limits['filesize'] ) ? $limits['filesize'] : $wgMaxShellFileSize );
2829
2830                 if ( $time > 0 || $mem > 0 || $filesize > 0 || $wallTime > 0 ) {
2831                         $cmd = '/bin/bash ' . escapeshellarg( "$IP/includes/limit.sh" ) . ' ' .
2832                                 escapeshellarg( $cmd ) . ' ' .
2833                                 escapeshellarg(
2834                                         "MW_INCLUDE_STDERR=" . ( $includeStderr ? '1' : '' ) . ';' .
2835                                         "MW_CPU_LIMIT=$time; " .
2836                                         'MW_CGROUP=' . escapeshellarg( $wgShellCgroup ) . '; ' .
2837                                         "MW_MEM_LIMIT=$mem; " .
2838                                         "MW_FILE_SIZE_LIMIT=$filesize; " .
2839                                         "MW_WALL_CLOCK_LIMIT=$wallTime; " .
2840                                         "MW_USE_LOG_PIPE=yes"
2841                                 );
2842                         $useLogPipe = true;
2843                 } elseif ( $includeStderr ) {
2844                         $cmd .= ' 2>&1';
2845                 }
2846         } elseif ( $includeStderr ) {
2847                 $cmd .= ' 2>&1';
2848         }
2849         wfDebug( "wfShellExec: $cmd\n" );
2850
2851         $desc = array(
2852                 0 => array( 'file', 'php://stdin', 'r' ),
2853                 1 => array( 'pipe', 'w' ),
2854                 2 => array( 'file', 'php://stderr', 'w' ) );
2855         if ( $useLogPipe ) {
2856                 $desc[3] = array( 'pipe', 'w' );
2857         }
2858
2859         # TODO/FIXME: This is a bad hack to workaround an HHVM bug that prevents
2860         # proc_open() from opening stdin/stdout, so use /dev/null *for now*
2861         # See bug 56597 / https://github.com/facebook/hhvm/issues/1247 for more info
2862         if ( wfIsHHVM() ) {
2863                 $desc[0] = array( 'file', '/dev/null', 'r' );
2864                 $desc[2] = array( 'file', '/dev/null', 'w' );
2865         }
2866
2867         $pipes = null;
2868         $proc = proc_open( $cmd, $desc, $pipes );
2869         if ( !$proc ) {
2870                 wfDebugLog( 'exec', "proc_open() failed: $cmd\n" );
2871                 $retval = -1;
2872                 return '';
2873         }
2874         $outBuffer = $logBuffer = '';
2875         $emptyArray = array();
2876         $status = false;
2877         $logMsg = false;
2878
2879         // According to the documentation, it is possible for stream_select()
2880         // to fail due to EINTR. I haven't managed to induce this in testing
2881         // despite sending various signals. If it did happen, the error
2882         // message would take the form:
2883         //
2884         // stream_select(): unable to select [4]: Interrupted system call (max_fd=5)
2885         //
2886         // where [4] is the value of the macro EINTR and "Interrupted system
2887         // call" is string which according to the Linux manual is "possibly"
2888         // localised according to LC_MESSAGES.
2889         $eintr = defined( 'SOCKET_EINTR' ) ? SOCKET_EINTR : 4;
2890         $eintrMessage = "stream_select(): unable to select [$eintr]";
2891
2892         // Build a table mapping resource IDs to pipe FDs to work around a
2893         // PHP 5.3 issue in which stream_select() does not preserve array keys
2894         // <https://bugs.php.net/bug.php?id=53427>.
2895         $fds = array();
2896         foreach ( $pipes as $fd => $pipe ) {
2897                 $fds[(int)$pipe] = $fd;
2898         }
2899
2900         while ( true ) {
2901                 $status = proc_get_status( $proc );
2902                 if ( !$status['running'] ) {
2903                         break;
2904                 }
2905                 $status = false;
2906
2907                 $readyPipes = $pipes;
2908
2909                 // Clear last error
2910                 @trigger_error( '' );
2911                 if ( @stream_select( $readyPipes, $emptyArray, $emptyArray, null ) === false ) {
2912                         $error = error_get_last();
2913                         if ( strncmp( $error['message'], $eintrMessage, strlen( $eintrMessage ) ) == 0 ) {
2914                                 continue;
2915                         } else {
2916                                 trigger_error( $error['message'], E_USER_WARNING );
2917                                 $logMsg = $error['message'];
2918                                 break;
2919                         }
2920                 }
2921                 foreach ( $readyPipes as $pipe ) {
2922                         $block = fread( $pipe, 65536 );
2923                         $fd = $fds[(int)$pipe];
2924                         if ( $block === '' ) {
2925                                 // End of file
2926                                 fclose( $pipes[$fd] );
2927                                 unset( $pipes[$fd] );
2928                                 if ( !$pipes ) {
2929                                         break 2;
2930                                 }
2931                         } elseif ( $block === false ) {
2932                                 // Read error
2933                                 $logMsg = "Error reading from pipe";
2934                                 break 2;
2935                         } elseif ( $fd == 1 ) {
2936                                 // From stdout
2937                                 $outBuffer .= $block;
2938                         } elseif ( $fd == 3 ) {
2939                                 // From log FD
2940                                 $logBuffer .= $block;
2941                                 if ( strpos( $block, "\n" ) !== false ) {
2942                                         $lines = explode( "\n", $logBuffer );
2943                                         $logBuffer = array_pop( $lines );
2944                                         foreach ( $lines as $line ) {
2945                                                 wfDebugLog( 'exec', $line );
2946                                         }
2947                                 }
2948                         }
2949                 }
2950         }
2951
2952         foreach ( $pipes as $pipe ) {
2953                 fclose( $pipe );
2954         }
2955
2956         // Use the status previously collected if possible, since proc_get_status()
2957         // just calls waitpid() which will not return anything useful the second time.
2958         if ( $status === false ) {
2959                 $status = proc_get_status( $proc );
2960         }
2961
2962         if ( $logMsg !== false ) {
2963                 // Read/select error
2964                 $retval = -1;
2965                 proc_close( $proc );
2966         } elseif ( $status['signaled'] ) {
2967                 $logMsg = "Exited with signal {$status['termsig']}";
2968                 $retval = 128 + $status['termsig'];
2969                 proc_close( $proc );
2970         } else {
2971                 if ( $status['running'] ) {
2972                         $retval = proc_close( $proc );
2973                 } else {
2974                         $retval = $status['exitcode'];
2975                         proc_close( $proc );
2976                 }
2977                 if ( $retval == 127 ) {
2978                         $logMsg = "Possibly missing executable file";
2979                 } elseif ( $retval >= 129 && $retval <= 192 ) {
2980                         $logMsg = "Probably exited with signal " . ( $retval - 128 );
2981                 }
2982         }
2983
2984         if ( $logMsg !== false ) {
2985                 wfDebugLog( 'exec', "$logMsg: $cmd\n" );
2986         }
2987
2988         return $outBuffer;
2989 }
2990
2991 /**
2992  * Execute a shell command, returning both stdout and stderr. Convenience
2993  * function, as all the arguments to wfShellExec can become unwieldy.
2994  *
2995  * @note This also includes errors from limit.sh, e.g. if $wgMaxShellFileSize is exceeded.
2996  * @param string $cmd Command line, properly escaped for shell.
2997  * @param &$retval null|Mixed optional, will receive the program's exit code.
2998  *                 (non-zero is usually failure)
2999  * @param array $environ optional environment variables which should be
3000  *                 added to the executed command environment.
3001  * @param array $limits optional array with limits(filesize, memory, time, walltime)
3002  *                 this overwrites the global wgShellMax* limits.
3003  * @return string collected stdout and stderr as a string
3004  */
3005 function wfShellExecWithStderr( $cmd, &$retval = null, $environ = array(), $limits = array() ) {
3006         return wfShellExec( $cmd, $retval, $environ, $limits, array( 'duplicateStderr' => true ) );
3007 }
3008
3009 /**
3010  * Workaround for http://bugs.php.net/bug.php?id=45132
3011  * escapeshellarg() destroys non-ASCII characters if LANG is not a UTF-8 locale
3012  */
3013 function wfInitShellLocale() {
3014         static $done = false;
3015         if ( $done ) {
3016                 return;
3017         }
3018         $done = true;
3019         global $wgShellLocale;
3020         if ( !wfIniGetBool( 'safe_mode' ) ) {
3021                 putenv( "LC_CTYPE=$wgShellLocale" );
3022                 setlocale( LC_CTYPE, $wgShellLocale );
3023         }
3024 }
3025
3026 /**
3027  * Alias to wfShellWikiCmd()
3028  * @see wfShellWikiCmd()
3029  */
3030 function wfShellMaintenanceCmd( $script, array $parameters = array(), array $options = array() ) {
3031         return wfShellWikiCmd( $script, $parameters, $options );
3032 }
3033
3034 /**
3035  * Generate a shell-escaped command line string to run a MediaWiki cli script.
3036  * Note that $parameters should be a flat array and an option with an argument
3037  * should consist of two consecutive items in the array (do not use "--option value").
3038  * @param string $script MediaWiki cli script path
3039  * @param array $parameters Arguments and options to the script
3040  * @param array $options Associative array of options:
3041  *              'php': The path to the php executable
3042  *              'wrapper': Path to a PHP wrapper to handle the maintenance script
3043  * @return Array
3044  */
3045 function wfShellWikiCmd( $script, array $parameters = array(), array $options = array() ) {
3046         global $wgPhpCli;
3047         // Give site config file a chance to run the script in a wrapper.
3048         // The caller may likely want to call wfBasename() on $script.
3049         wfRunHooks( 'wfShellWikiCmd', array( &$script, &$parameters, &$options ) );
3050         $cmd = isset( $options['php'] ) ? array( $options['php'] ) : array( $wgPhpCli );
3051         if ( isset( $options['wrapper'] ) ) {
3052                 $cmd[] = $options['wrapper'];
3053         }
3054         $cmd[] = $script;
3055         // Escape each parameter for shell
3056         return implode( " ", array_map( 'wfEscapeShellArg', array_merge( $cmd, $parameters ) ) );
3057 }
3058
3059 /**
3060  * wfMerge attempts to merge differences between three texts.
3061  * Returns true for a clean merge and false for failure or a conflict.
3062  *
3063  * @param $old String
3064  * @param $mine String
3065  * @param $yours String
3066  * @param $result String
3067  * @return Bool
3068  */
3069 function wfMerge( $old, $mine, $yours, &$result ) {
3070         global $wgDiff3;
3071
3072         # This check may also protect against code injection in
3073         # case of broken installations.
3074         wfSuppressWarnings();
3075         $haveDiff3 = $wgDiff3 && file_exists( $wgDiff3 );
3076         wfRestoreWarnings();
3077
3078         if ( !$haveDiff3 ) {
3079                 wfDebug( "diff3 not found\n" );
3080                 return false;
3081         }
3082
3083         # Make temporary files
3084         $td = wfTempDir();
3085         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
3086         $mytextFile = fopen( $mytextName = tempnam( $td, 'merge-mine-' ), 'w' );
3087         $yourtextFile = fopen( $yourtextName = tempnam( $td, 'merge-your-' ), 'w' );
3088
3089         # NOTE: diff3 issues a warning to stderr if any of the files does not end with
3090         #       a newline character. To avoid this, we normalize the trailing whitespace before
3091         #       creating the diff.
3092
3093         fwrite( $oldtextFile, rtrim( $old ) . "\n" );
3094         fclose( $oldtextFile );
3095         fwrite( $mytextFile, rtrim( $mine ) . "\n" );
3096         fclose( $mytextFile );
3097         fwrite( $yourtextFile, rtrim( $yours ) . "\n" );
3098         fclose( $yourtextFile );
3099
3100         # Check for a conflict
3101         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a --overlap-only ' .
3102                 wfEscapeShellArg( $mytextName ) . ' ' .
3103                 wfEscapeShellArg( $oldtextName ) . ' ' .
3104                 wfEscapeShellArg( $yourtextName );
3105         $handle = popen( $cmd, 'r' );
3106
3107         if ( fgets( $handle, 1024 ) ) {
3108                 $conflict = true;
3109         } else {
3110                 $conflict = false;
3111         }
3112         pclose( $handle );
3113
3114         # Merge differences
3115         $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a -e --merge ' .
3116                 wfEscapeShellArg( $mytextName, $oldtextName, $yourtextName );
3117         $handle = popen( $cmd, 'r' );
3118         $result = '';
3119         do {
3120                 $data = fread( $handle, 8192 );
3121                 if ( strlen( $data ) == 0 ) {
3122                         break;
3123                 }
3124                 $result .= $data;
3125         } while ( true );
3126         pclose( $handle );
3127         unlink( $mytextName );
3128         unlink( $oldtextName );
3129         unlink( $yourtextName );
3130
3131         if ( $result === '' && $old !== '' && !$conflict ) {
3132                 wfDebug( "Unexpected null result from diff3. Command: $cmd\n" );
3133                 $conflict = true;
3134         }
3135         return !$conflict;
3136 }
3137
3138 /**
3139  * Returns unified plain-text diff of two texts.
3140  * Useful for machine processing of diffs.
3141  *
3142  * @param string $before the text before the changes.
3143  * @param string $after the text after the changes.
3144  * @param string $params command-line options for the diff command.
3145  * @return String: unified diff of $before and $after
3146  */
3147 function wfDiff( $before, $after, $params = '-u' ) {
3148         if ( $before == $after ) {
3149                 return '';
3150         }
3151
3152         global $wgDiff;
3153         wfSuppressWarnings();
3154         $haveDiff = $wgDiff && file_exists( $wgDiff );
3155         wfRestoreWarnings();
3156
3157         # This check may also protect against code injection in
3158         # case of broken installations.
3159         if ( !$haveDiff ) {
3160                 wfDebug( "diff executable not found\n" );
3161                 $diffs = new Diff( explode( "\n", $before ), explode( "\n", $after ) );
3162                 $format = new UnifiedDiffFormatter();
3163                 return $format->format( $diffs );
3164         }
3165
3166         # Make temporary files
3167         $td = wfTempDir();
3168         $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
3169         $newtextFile = fopen( $newtextName = tempnam( $td, 'merge-your-' ), 'w' );
3170
3171         fwrite( $oldtextFile, $before );
3172         fclose( $oldtextFile );
3173         fwrite( $newtextFile, $after );
3174         fclose( $newtextFile );
3175
3176         // Get the diff of the two files
3177         $cmd = "$wgDiff " . $params . ' ' . wfEscapeShellArg( $oldtextName, $newtextName );
3178
3179         $h = popen( $cmd, 'r' );
3180
3181         $diff = '';
3182
3183         do {
3184                 $data = fread( $h, 8192 );
3185                 if ( strlen( $data ) == 0 ) {
3186                         break;
3187                 }
3188                 $diff .= $data;
3189         } while ( true );
3190
3191         // Clean up
3192         pclose( $h );
3193         unlink( $oldtextName );
3194         unlink( $newtextName );
3195
3196         // Kill the --- and +++ lines. They're not useful.
3197         $diff_lines = explode( "\n", $diff );
3198         if ( strpos( $diff_lines[0], '---' ) === 0 ) {
3199                 unset( $diff_lines[0] );
3200         }
3201         if ( strpos( $diff_lines[1], '+++' ) === 0 ) {
3202                 unset( $diff_lines[1] );
3203         }
3204
3205         $diff = implode( "\n", $diff_lines );
3206
3207         return $diff;
3208 }
3209
3210 /**
3211  * This function works like "use VERSION" in Perl, the program will die with a
3212  * backtrace if the current version of PHP is less than the version provided
3213  *
3214  * This is useful for extensions which due to their nature are not kept in sync
3215  * with releases, and might depend on other versions of PHP than the main code
3216  *
3217  * Note: PHP might die due to parsing errors in some cases before it ever
3218  *       manages to call this function, such is life
3219  *
3220  * @see perldoc -f use
3221  *
3222  * @param $req_ver Mixed: the version to check, can be a string, an integer, or
3223  *                 a float
3224  * @throws MWException
3225  */
3226 function wfUsePHP( $req_ver ) {
3227         $php_ver = PHP_VERSION;
3228
3229         if ( version_compare( $php_ver, (string)$req_ver, '<' ) ) {
3230                 throw new MWException( "PHP $req_ver required--this is only $php_ver" );
3231         }
3232 }
3233
3234 /**
3235  * This function works like "use VERSION" in Perl except it checks the version
3236  * of MediaWiki, the program will die with a backtrace if the current version
3237  * of MediaWiki is less than the version provided.
3238  *
3239  * This is useful for extensions which due to their nature are not kept in sync
3240  * with releases
3241  *
3242  * Note: Due to the behavior of PHP's version_compare() which is used in this
3243  * function, if you want to allow the 'wmf' development versions add a 'c' (or
3244  * any single letter other than 'a', 'b' or 'p') as a post-fix to your
3245  * targeted version number. For example if you wanted to allow any variation
3246  * of 1.22 use `wfUseMW( '1.22c' )`. Using an 'a' or 'b' instead of 'c' will
3247  * not result in the same comparison due to the internal logic of
3248  * version_compare().
3249  *
3250  * @see perldoc -f use
3251  *
3252  * @param $req_ver Mixed: the version to check, can be a string, an integer, or
3253  *                 a float
3254  * @throws MWException
3255  */
3256 function wfUseMW( $req_ver ) {
3257         global $wgVersion;
3258
3259         if ( version_compare( $wgVersion, (string)$req_ver, '<' ) ) {
3260                 throw new MWException( "MediaWiki $req_ver required--this is only $wgVersion" );
3261         }
3262 }
3263
3264 /**
3265  * Return the final portion of a pathname.
3266  * Reimplemented because PHP5's "basename()" is buggy with multibyte text.
3267  * http://bugs.php.net/bug.php?id=33898
3268  *
3269  * PHP's basename() only considers '\' a pathchar on Windows and Netware.
3270  * We'll consider it so always, as we don't want '\s' in our Unix paths either.
3271  *
3272  * @param $path String
3273  * @param string $suffix to remove if present
3274  * @return String
3275  */
3276 function wfBaseName( $path, $suffix = '' ) {
3277         if ( $suffix == '' ) {
3278                 $encSuffix = '';
3279         } else {
3280                 $encSuffix = '(?:' . preg_quote( $suffix, '#' ) . ')?';
3281         }
3282
3283         $matches = array();
3284         if ( preg_match( "#([^/\\\\]*?){$encSuffix}[/\\\\]*$#", $path, $matches ) ) {
3285                 return $matches[1];
3286         } else {
3287                 return '';
3288         }
3289 }
3290
3291 /**
3292  * Generate a relative path name to the given file.
3293  * May explode on non-matching case-insensitive paths,
3294  * funky symlinks, etc.
3295  *
3296  * @param string $path absolute destination path including target filename
3297  * @param string $from Absolute source path, directory only
3298  * @return String
3299  */
3300 function wfRelativePath( $path, $from ) {
3301         // Normalize mixed input on Windows...
3302         $path = str_replace( '/', DIRECTORY_SEPARATOR, $path );
3303         $from = str_replace( '/', DIRECTORY_SEPARATOR, $from );
3304
3305         // Trim trailing slashes -- fix for drive root
3306         $path = rtrim( $path, DIRECTORY_SEPARATOR );
3307         $from = rtrim( $from, DIRECTORY_SEPARATOR );
3308
3309         $pieces = explode( DIRECTORY_SEPARATOR, dirname( $path ) );
3310         $against = explode( DIRECTORY_SEPARATOR, $from );
3311
3312         if ( $pieces[0] !== $against[0] ) {
3313                 // Non-matching Windows drive letters?
3314                 // Return a full path.
3315                 return $path;
3316         }
3317
3318         // Trim off common prefix
3319         while ( count( $pieces ) && count( $against )
3320                 && $pieces[0] == $against[0] ) {
3321                 array_shift( $pieces );
3322                 array_shift( $against );
3323         }
3324
3325         // relative dots to bump us to the parent
3326         while ( count( $against ) ) {
3327                 array_unshift( $pieces, '..' );
3328                 array_shift( $against );
3329         }
3330
3331         array_push( $pieces, wfBaseName( $path ) );
3332
3333         return implode( DIRECTORY_SEPARATOR, $pieces );
3334 }
3335
3336 /**
3337  * Convert an arbitrarily-long digit string from one numeric base
3338  * to another, optionally zero-padding to a minimum column width.
3339  *
3340  * Supports base 2 through 36; digit values 10-36 are represented
3341  * as lowercase letters a-z. Input is case-insensitive.
3342  *
3343  * @param string $input Input number
3344  * @param int $sourceBase Base of the input number
3345  * @param int $destBase Desired base of the output
3346  * @param int $pad Minimum number of digits in the output (pad with zeroes)
3347  * @param bool $lowercase Whether to output in lowercase or uppercase
3348  * @param string $engine Either "gmp", "bcmath", or "php"
3349  * @return string|bool The output number as a string, or false on error
3350  */
3351 function wfBaseConvert( $input, $sourceBase, $destBase, $pad = 1,
3352         $lowercase = true, $engine = 'auto'
3353 ) {
3354         $input = (string)$input;
3355         if (
3356                 $sourceBase < 2 ||
3357                 $sourceBase > 36 ||
3358                 $destBase < 2 ||
3359                 $destBase > 36 ||
3360                 $sourceBase != (int)$sourceBase ||
3361                 $destBase != (int)$destBase ||
3362                 $pad != (int)$pad ||
3363                 !preg_match(
3364                         "/^[" . substr( '0123456789abcdefghijklmnopqrstuvwxyz', 0, $sourceBase ) . "]+$/i",
3365                         $input
3366                 )
3367         ) {
3368                 return false;
3369         }
3370
3371         static $baseChars = array(
3372                 10 => 'a', 11 => 'b', 12 => 'c', 13 => 'd', 14 => 'e', 15 => 'f',
3373                 16 => 'g', 17 => 'h', 18 => 'i', 19 => 'j', 20 => 'k', 21 => 'l',
3374                 22 => 'm', 23 => 'n', 24 => 'o', 25 => 'p', 26 => 'q', 27 => 'r',
3375                 28 => 's', 29 => 't', 30 => 'u', 31 => 'v', 32 => 'w', 33 => 'x',
3376                 34 => 'y', 35 => 'z',
3377
3378                 '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5,
3379                 '6' => 6, '7' => 7, '8' => 8, '9' => 9, 'a' => 10, 'b' => 11,
3380                 'c' => 12, 'd' => 13, 'e' => 14, 'f' => 15, 'g' => 16, 'h' => 17,
3381                 'i' => 18, 'j' => 19, 'k' => 20, 'l' => 21, 'm' => 22, 'n' => 23,
3382                 'o' => 24, 'p' => 25, 'q' => 26, 'r' => 27, 's' => 28, 't' => 29,
3383                 'u' => 30, 'v' => 31, 'w' => 32, 'x' => 33, 'y' => 34, 'z' => 35
3384         );
3385
3386         if ( extension_loaded( 'gmp' ) && ( $engine == 'auto' || $engine == 'gmp' ) ) {
3387                 $result = gmp_strval( gmp_init( $input, $sourceBase ), $destBase );
3388         } elseif ( extension_loaded( 'bcmath' ) && ( $engine == 'auto' || $engine == 'bcmath' ) ) {
3389                 $decimal = '0';
3390                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3391                         $decimal = bcmul( $decimal, $sourceBase );
3392                         $decimal = bcadd( $decimal, $baseChars[$char] );
3393                 }
3394
3395                 for ( $result = ''; bccomp( $decimal, 0 ); $decimal = bcdiv( $decimal, $destBase, 0 ) ) {
3396                         $result .= $baseChars[bcmod( $decimal, $destBase )];
3397                 }
3398
3399                 $result = strrev( $result );
3400         } else {
3401                 $inDigits = array();
3402                 foreach ( str_split( strtolower( $input ) ) as $char ) {
3403                         $inDigits[] = $baseChars[$char];
3404                 }
3405
3406                 // Iterate over the input, modulo-ing out an output digit
3407                 // at a time until input is gone.
3408                 $result = '';
3409                 while ( $inDigits ) {
3410                         $work = 0;
3411                         $workDigits = array();
3412
3413                         // Long division...
3414                         foreach ( $inDigits as $digit ) {
3415                                 $work *= $sourceBase;
3416                                 $work += $digit;
3417
3418                                 if ( $workDigits || $work >= $destBase ) {
3419                                         $workDigits[] = (int)( $work / $destBase );
3420                                 }
3421                                 $work %= $destBase;
3422                         }
3423
3424                         // All that division leaves us with a remainder,
3425                         // which is conveniently our next output digit.
3426                         $result .= $baseChars[$work];
3427
3428                         // And we continue!
3429                         $inDigits = $workDigits;
3430                 }
3431
3432                 $result = strrev( $result );
3433         }
3434
3435         if ( !$lowercase ) {
3436                 $result = strtoupper( $result );
3437         }
3438
3439         return str_pad( $result, $pad, '0', STR_PAD_LEFT );
3440 }
3441
3442 /**
3443  * @return bool
3444  */
3445 function wfHttpOnlySafe() {
3446         global $wgHttpOnlyBlacklist;
3447
3448         if ( isset( $_SERVER['HTTP_USER_AGENT'] ) ) {
3449                 foreach ( $wgHttpOnlyBlacklist as $regex ) {
3450                         if ( preg_match( $regex, $_SERVER['HTTP_USER_AGENT'] ) ) {
3451                                 return false;
3452                         }
3453                 }
3454         }
3455
3456         return true;
3457 }
3458
3459 /**
3460  * Check if there is sufficient entropy in php's built-in session generation
3461  * @return bool true = there is sufficient entropy
3462  */
3463 function wfCheckEntropy() {
3464         return (
3465                         ( wfIsWindows() && version_compare( PHP_VERSION, '5.3.3', '>=' ) )
3466                         || ini_get( 'session.entropy_file' )
3467                 )
3468                 && intval( ini_get( 'session.entropy_length' ) ) >= 32;
3469 }
3470
3471 /**
3472  * Override session_id before session startup if php's built-in
3473  * session generation code is not secure.
3474  */
3475 function wfFixSessionID() {
3476         // If the cookie or session id is already set we already have a session and should abort
3477         if ( isset( $_COOKIE[session_name()] ) || session_id() ) {
3478                 return;
3479         }
3480
3481         // PHP's built-in session entropy is enabled if:
3482         // - entropy_file is set or you're on Windows with php 5.3.3+
3483         // - AND entropy_length is > 0
3484         // We treat it as disabled if it doesn't have an entropy length of at least 32
3485         $entropyEnabled = wfCheckEntropy();
3486
3487         // If built-in entropy is not enabled or not sufficient override PHP's
3488         // built in session id generation code
3489         if ( !$entropyEnabled ) {
3490                 wfDebug( __METHOD__ . ": PHP's built in entropy is disabled or not sufficient, " .
3491                         "overriding session id generation using our cryptrand source.\n" );
3492                 session_id( MWCryptRand::generateHex( 32 ) );
3493         }
3494 }
3495
3496 /**
3497  * Reset the session_id
3498  * @since 1.22
3499  */
3500 function wfResetSessionID() {
3501         global $wgCookieSecure;
3502         $oldSessionId = session_id();
3503         $cookieParams = session_get_cookie_params();
3504         if ( wfCheckEntropy() && $wgCookieSecure == $cookieParams['secure'] ) {
3505                 session_regenerate_id( false );
3506         } else {
3507                 $tmp = $_SESSION;
3508                 session_destroy();
3509                 wfSetupSession( MWCryptRand::generateHex( 32 ) );
3510                 $_SESSION = $tmp;
3511         }
3512         $newSessionId = session_id();
3513         wfRunHooks( 'ResetSessionID', array( $oldSessionId, $newSessionId ) );
3514 }
3515
3516 /**
3517  * Initialise php session
3518  *
3519  * @param $sessionId Bool
3520  */
3521 function wfSetupSession( $sessionId = false ) {
3522         global $wgSessionsInMemcached, $wgSessionsInObjectCache, $wgCookiePath, $wgCookieDomain,
3523                         $wgCookieSecure, $wgCookieHttpOnly, $wgSessionHandler;
3524         if ( $wgSessionsInObjectCache || $wgSessionsInMemcached ) {
3525                 ObjectCacheSessionHandler::install();
3526         } elseif ( $wgSessionHandler && $wgSessionHandler != ini_get( 'session.save_handler' ) ) {
3527                 # Only set this if $wgSessionHandler isn't null and session.save_handler
3528                 # hasn't already been set to the desired value (that causes errors)
3529                 ini_set( 'session.save_handler', $wgSessionHandler );
3530         }
3531         $httpOnlySafe = wfHttpOnlySafe() && $wgCookieHttpOnly;
3532         wfDebugLog( 'cookie',
3533                 'session_set_cookie_params: "' . implode( '", "',
3534                         array(
3535                                 0,
3536                                 $wgCookiePath,
3537                                 $wgCookieDomain,
3538                                 $wgCookieSecure,
3539                                 $httpOnlySafe ) ) . '"' );
3540         session_set_cookie_params( 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $httpOnlySafe );
3541         session_cache_limiter( 'private, must-revalidate' );
3542         if ( $sessionId ) {
3543                 session_id( $sessionId );
3544         } else {
3545                 wfFixSessionID();
3546         }
3547         wfSuppressWarnings();
3548         session_start();
3549         wfRestoreWarnings();
3550 }
3551
3552 /**
3553  * Get an object from the precompiled serialized directory
3554  *
3555  * @param $name String
3556  * @return Mixed: the variable on success, false on failure
3557  */
3558 function wfGetPrecompiledData( $name ) {
3559         global $IP;
3560
3561         $file = "$IP/serialized/$name";
3562         if ( file_exists( $file ) ) {
3563                 $blob = file_get_contents( $file );
3564                 if ( $blob ) {
3565                         return unserialize( $blob );
3566                 }
3567         }
3568         return false;
3569 }
3570
3571 /**
3572  * Get a cache key
3573  *
3574  * @param varargs
3575  * @return String
3576  */
3577 function wfMemcKey( /*... */ ) {
3578         global $wgCachePrefix;
3579         $prefix = $wgCachePrefix === false ? wfWikiID() : $wgCachePrefix;
3580         $args = func_get_args();
3581         $key = $prefix . ':' . implode( ':', $args );
3582         $key = str_replace( ' ', '_', $key );
3583         return $key;
3584 }
3585
3586 /**
3587  * Get a cache key for a foreign DB
3588  *
3589  * @param $db String
3590  * @param $prefix String
3591  * @param varargs String
3592  * @return String
3593  */
3594 function wfForeignMemcKey( $db, $prefix /*, ... */ ) {
3595         $args = array_slice( func_get_args(), 2 );
3596         if ( $prefix ) {
3597                 $key = "$db-$prefix:" . implode( ':', $args );
3598         } else {
3599                 $key = $db . ':' . implode( ':', $args );
3600         }
3601         return str_replace( ' ', '_', $key );
3602 }
3603
3604 /**
3605  * Get an ASCII string identifying this wiki
3606  * This is used as a prefix in memcached keys
3607  *
3608  * @return String
3609  */
3610 function wfWikiID() {
3611         global $wgDBprefix, $wgDBname;
3612         if ( $wgDBprefix ) {
3613                 return "$wgDBname-$wgDBprefix";
3614         } else {
3615                 return $wgDBname;
3616         }
3617 }
3618
3619 /**
3620  * Split a wiki ID into DB name and table prefix
3621  *
3622  * @param $wiki String
3623  *
3624  * @return array
3625  */
3626 function wfSplitWikiID( $wiki ) {
3627         $bits = explode( '-', $wiki, 2 );
3628         if ( count( $bits ) < 2 ) {
3629                 $bits[] = '';
3630         }
3631         return $bits;
3632 }
3633
3634 /**
3635  * Get a Database object.
3636  *
3637  * @param $db Integer: index of the connection to get. May be DB_MASTER for the
3638  *            master (for write queries), DB_SLAVE for potentially lagged read
3639  *            queries, or an integer >= 0 for a particular server.
3640  *
3641  * @param $groups Mixed: query groups. An array of group names that this query
3642  *                belongs to. May contain a single string if the query is only
3643  *                in one group.
3644  *
3645  * @param string $wiki the wiki ID, or false for the current wiki
3646  *
3647  * Note: multiple calls to wfGetDB(DB_SLAVE) during the course of one request
3648  * will always return the same object, unless the underlying connection or load
3649  * balancer is manually destroyed.
3650  *
3651  * Note 2: use $this->getDB() in maintenance scripts that may be invoked by
3652  * updater to ensure that a proper database is being updated.
3653  *
3654  * @return DatabaseBase
3655  */
3656 function &wfGetDB( $db, $groups = array(), $wiki = false ) {
3657         return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
3658 }
3659
3660 /**
3661  * Get a load balancer object.
3662  *
3663  * @param string $wiki wiki ID, or false for the current wiki
3664  * @return LoadBalancer
3665  */
3666 function wfGetLB( $wiki = false ) {
3667         return wfGetLBFactory()->getMainLB( $wiki );
3668 }
3669
3670 /**
3671  * Get the load balancer factory object
3672  *
3673  * @return LBFactory
3674  */
3675 function &wfGetLBFactory() {
3676         return LBFactory::singleton();
3677 }
3678
3679 /**
3680  * Find a file.
3681  * Shortcut for RepoGroup::singleton()->findFile()
3682  *
3683  * @param string $title or Title object
3684  * @param array $options Associative array of options:
3685  *     time:           requested time for an archived image, or false for the
3686  *                     current version. An image object will be returned which was
3687  *                     created at the specified time.
3688  *
3689  *     ignoreRedirect: If true, do not follow file redirects
3690  *
3691  *     private:        If true, return restricted (deleted) files if the current
3692  *                     user is allowed to view them. Otherwise, such files will not
3693  *                     be found.
3694  *
3695  *     bypassCache:    If true, do not use the process-local cache of File objects
3696  *
3697  * @return File, or false if the file does not exist
3698  */
3699 function wfFindFile( $title, $options = array() ) {
3700         return RepoGroup::singleton()->findFile( $title, $options );
3701 }
3702
3703 /**
3704  * Get an object referring to a locally registered file.
3705  * Returns a valid placeholder object if the file does not exist.
3706  *
3707  * @param $title Title|String
3708  * @return LocalFile|null A File, or null if passed an invalid Title
3709  */
3710 function wfLocalFile( $title ) {
3711         return RepoGroup::singleton()->getLocalRepo()->newFile( $title );
3712 }
3713
3714 /**
3715  * Stream a file to the browser. Back-compat alias for StreamFile::stream()
3716  * @deprecated since 1.19
3717  */
3718 function wfStreamFile( $fname, $headers = array() ) {
3719         wfDeprecated( __FUNCTION__, '1.19' );
3720         StreamFile::stream( $fname, $headers );
3721 }
3722
3723 /**
3724  * Should low-performance queries be disabled?
3725  *
3726  * @return Boolean
3727  * @codeCoverageIgnore
3728  */
3729 function wfQueriesMustScale() {
3730         global $wgMiserMode;
3731         return $wgMiserMode
3732                 || ( SiteStats::pages() > 100000
3733                 && SiteStats::edits() > 1000000
3734                 && SiteStats::users() > 10000 );
3735 }
3736
3737 /**
3738  * Get the path to a specified script file, respecting file
3739  * extensions; this is a wrapper around $wgScriptExtension etc.
3740  * except for 'index' and 'load' which use $wgScript/$wgLoadScript
3741  *
3742  * @param string $script script filename, sans extension
3743  * @return String
3744  */
3745 function wfScript( $script = 'index' ) {
3746         global $wgScriptPath, $wgScriptExtension, $wgScript, $wgLoadScript;
3747         if ( $script === 'index' ) {
3748                 return $wgScript;
3749         } elseif ( $script === 'load' ) {
3750                 return $wgLoadScript;
3751         } else {
3752                 return "{$wgScriptPath}/{$script}{$wgScriptExtension}";
3753         }
3754 }
3755
3756 /**
3757  * Get the script URL.
3758  *
3759  * @return string script URL
3760  */
3761 function wfGetScriptUrl() {
3762         if ( isset( $_SERVER['SCRIPT_NAME'] ) ) {
3763                 #
3764                 # as it was called, minus the query string.
3765                 #
3766                 # Some sites use Apache rewrite rules to handle subdomains,
3767                 # and have PHP set up in a weird way that causes PHP_SELF
3768                 # to contain the rewritten URL instead of the one that the
3769                 # outside world sees.
3770                 #
3771                 # If in this mode, use SCRIPT_URL instead, which mod_rewrite
3772                 # provides containing the "before" URL.
3773                 return $_SERVER['SCRIPT_NAME'];
3774         } else {
3775                 return $_SERVER['URL'];
3776         }
3777 }
3778
3779 /**
3780  * Convenience function converts boolean values into "true"
3781  * or "false" (string) values
3782  *
3783  * @param $value Boolean
3784  * @return String
3785  */
3786 function wfBoolToStr( $value ) {
3787         return $value ? 'true' : 'false';
3788 }
3789
3790 /**
3791  * Get a platform-independent path to the null file, e.g. /dev/null
3792  *
3793  * @return string
3794  */
3795 function wfGetNull() {
3796         return wfIsWindows() ? 'NUL' : '/dev/null';
3797 }
3798
3799 /**
3800  * Modern version of wfWaitForSlaves(). Instead of looking at replication lag
3801  * and waiting for it to go down, this waits for the slaves to catch up to the
3802  * master position. Use this when updating very large numbers of rows, as
3803  * in maintenance scripts, to avoid causing too much lag.  Of course, this is
3804  * a no-op if there are no slaves.
3805  *
3806  * @param int|bool $maxLag (deprecated)
3807  * @param mixed $wiki Wiki identifier accepted by wfGetLB
3808  * @param string|bool $cluster Cluster name accepted by LBFactory. Default: false.
3809  */
3810 function wfWaitForSlaves( $maxLag = false, $wiki = false, $cluster = false ) {
3811         if ( $cluster !== false ) {
3812                 $lb = wfGetLBFactory()->getExternalLB( $cluster );
3813         } else {
3814                 $lb = wfGetLB( $wiki );
3815         }
3816
3817         // bug 27975 - Don't try to wait for slaves if there are none
3818         // Prevents permission error when getting master position
3819         if ( $lb->getServerCount() > 1 ) {
3820                 $dbw = $lb->getConnection( DB_MASTER, array(), $wiki );
3821                 $pos = $dbw->getMasterPos();
3822                 // The DBMS may not support getMasterPos() or the whole
3823                 // load balancer might be fake (e.g. $wgAllDBsAreLocalhost).
3824                 if ( $pos !== false ) {
3825                         $lb->waitForAll( $pos );
3826                 }
3827         }
3828 }
3829
3830 /**
3831  * Count down from $n to zero on the terminal, with a one-second pause
3832  * between showing each number. For use in command-line scripts.
3833  * @codeCoverageIgnore
3834  * @param $n int
3835  */
3836 function wfCountDown( $n ) {
3837         for ( $i = $n; $i >= 0; $i-- ) {
3838                 if ( $i != $n ) {
3839                         echo str_repeat( "\x08", strlen( $i + 1 ) );
3840                 }
3841                 echo $i;
3842                 flush();
3843                 if ( $i ) {
3844                         sleep( 1 );
3845                 }
3846         }
3847         echo "\n";
3848 }
3849
3850 /**
3851  * Generate a random 32-character hexadecimal token.
3852  * @param $salt Mixed: some sort of salt, if necessary, to add to random
3853  *              characters before hashing.
3854  * @return string
3855  * @codeCoverageIgnore
3856  * @deprecated since 1.20; Please use MWCryptRand for security purposes and
3857  * wfRandomString for pseudo-random strings
3858  * @warning This method is NOT secure. Additionally it has many callers that
3859  * use it for pseudo-random purposes.
3860  */
3861 function wfGenerateToken( $salt = '' ) {
3862         wfDeprecated( __METHOD__, '1.20' );
3863         $salt = serialize( $salt );
3864         return md5( mt_rand( 0, 0x7fffffff ) . $salt );
3865 }
3866
3867 /**
3868  * Replace all invalid characters with -
3869  * Additional characters can be defined in $wgIllegalFileChars (see bug 20489)
3870  * By default, $wgIllegalFileChars = ':'
3871  *
3872  * @param $name Mixed: filename to process
3873  * @return String
3874  */
3875 function wfStripIllegalFilenameChars( $name ) {
3876         global $wgIllegalFileChars;
3877         $illegalFileChars = $wgIllegalFileChars ? "|[" . $wgIllegalFileChars . "]" : '';
3878         $name = wfBaseName( $name );
3879         $name = preg_replace(
3880                 "/[^" . Title::legalChars() . "]" . $illegalFileChars . "/",
3881                 '-',
3882                 $name
3883         );
3884         return $name;
3885 }
3886
3887 /**
3888  * Set PHP's memory limit to the larger of php.ini or $wgMemoryLimit;
3889  *
3890  * @return Integer value memory was set to.
3891  */
3892 function wfMemoryLimit() {
3893         global $wgMemoryLimit;
3894         $memlimit = wfShorthandToInteger( ini_get( 'memory_limit' ) );
3895         if ( $memlimit != -1 ) {
3896                 $conflimit = wfShorthandToInteger( $wgMemoryLimit );
3897                 if ( $conflimit == -1 ) {
3898                         wfDebug( "Removing PHP's memory limit\n" );
3899                         wfSuppressWarnings();
3900                         ini_set( 'memory_limit', $conflimit );
3901                         wfRestoreWarnings();
3902                         return $conflimit;
3903                 } elseif ( $conflimit > $memlimit ) {
3904                         wfDebug( "Raising PHP's memory limit to $conflimit bytes\n" );
3905                         wfSuppressWarnings();
3906                         ini_set( 'memory_limit', $conflimit );
3907                         wfRestoreWarnings();
3908                         return $conflimit;
3909                 }
3910         }
3911         return $memlimit;
3912 }
3913
3914 /**
3915  * Converts shorthand byte notation to integer form
3916  *
3917  * @param $string String
3918  * @return Integer
3919  */
3920 function wfShorthandToInteger( $string = '' ) {
3921         $string = trim( $string );
3922         if ( $string === '' ) {
3923                 return -1;
3924         }
3925         $last = $string[strlen( $string ) - 1];
3926         $val = intval( $string );
3927         switch ( $last ) {
3928                 case 'g':
3929                 case 'G':
3930                         $val *= 1024;
3931                         // break intentionally missing
3932                 case 'm':
3933                 case 'M':
3934                         $val *= 1024;
3935                         // break intentionally missing
3936                 case 'k':
3937                 case 'K':
3938                         $val *= 1024;
3939         }
3940
3941         return $val;
3942 }
3943
3944 /**
3945  * Get the normalised IETF language tag
3946  * See unit test for examples.
3947  *
3948  * @param string $code The language code.
3949  * @return String: The language code which complying with BCP 47 standards.
3950  */
3951 function wfBCP47( $code ) {
3952         $codeSegment = explode( '-', $code );
3953         $codeBCP = array();
3954         foreach ( $codeSegment as $segNo => $seg ) {
3955                 // when previous segment is x, it is a private segment and should be lc
3956                 if ( $segNo > 0 && strtolower( $codeSegment[( $segNo - 1 )] ) == 'x' ) {
3957                         $codeBCP[$segNo] = strtolower( $seg );
3958                 // ISO 3166 country code
3959                 } elseif ( ( strlen( $seg ) == 2 ) && ( $segNo > 0 ) ) {
3960                         $codeBCP[$segNo] = strtoupper( $seg );
3961                 // ISO 15924 script code
3962                 } elseif ( ( strlen( $seg ) == 4 ) && ( $segNo > 0 ) ) {
3963                         $codeBCP[$segNo] = ucfirst( strtolower( $seg ) );
3964                 // Use lowercase for other cases
3965                 } else {
3966                         $codeBCP[$segNo] = strtolower( $seg );
3967                 }
3968         }
3969         $langCode = implode( '-', $codeBCP );
3970         return $langCode;
3971 }
3972
3973 /**
3974  * Get a cache object.
3975  *
3976  * @param $inputType integer Cache type, one the the CACHE_* constants.
3977  * @return BagOStuff
3978  */
3979 function wfGetCache( $inputType ) {
3980         return ObjectCache::getInstance( $inputType );
3981 }
3982
3983 /**
3984  * Get the main cache object
3985  *
3986  * @return BagOStuff
3987  */
3988 function wfGetMainCache() {
3989         global $wgMainCacheType;
3990         return ObjectCache::getInstance( $wgMainCacheType );
3991 }
3992
3993 /**
3994  * Get the cache object used by the message cache
3995  *
3996  * @return BagOStuff
3997  */
3998 function wfGetMessageCacheStorage() {
3999         global $wgMessageCacheType;
4000         return ObjectCache::getInstance( $wgMessageCacheType );
4001 }
4002
4003 /**
4004  * Get the cache object used by the parser cache
4005  *
4006  * @return BagOStuff
4007  */
4008 function wfGetParserCacheStorage() {
4009         global $wgParserCacheType;
4010         return ObjectCache::getInstance( $wgParserCacheType );
4011 }
4012
4013 /**
4014  * Get the cache object used by the language converter
4015  *
4016  * @return BagOStuff
4017  */
4018 function wfGetLangConverterCacheStorage() {
4019         global $wgLanguageConverterCacheType;
4020         return ObjectCache::getInstance( $wgLanguageConverterCacheType );
4021 }
4022
4023 /**
4024  * Call hook functions defined in $wgHooks
4025  *
4026  * @param string $event event name
4027  * @param array $args parameters passed to hook functions
4028  * @return Boolean True if no handler aborted the hook
4029  */
4030 function wfRunHooks( $event, array $args = array() ) {
4031         return Hooks::run( $event, $args );
4032 }
4033
4034 /**
4035  * Wrapper around php's unpack.
4036  *
4037  * @param string $format The format string (See php's docs)
4038  * @param $data: A binary string of binary data
4039  * @param $length integer or false: The minimum length of $data. This is to
4040  *      prevent reading beyond the end of $data. false to disable the check.
4041  *
4042  * Also be careful when using this function to read unsigned 32 bit integer
4043  * because php might make it negative.
4044  *
4045  * @throws MWException if $data not long enough, or if unpack fails
4046  * @return array Associative array of the extracted data
4047  */
4048 function wfUnpack( $format, $data, $length = false ) {
4049         if ( $length !== false ) {
4050                 $realLen = strlen( $data );
4051                 if ( $realLen < $length ) {
4052                         throw new MWException( "Tried to use wfUnpack on a "
4053                                 . "string of length $realLen, but needed one "
4054                                 . "of at least length $length."
4055                         );
4056                 }
4057         }
4058
4059         wfSuppressWarnings();
4060         $result = unpack( $format, $data );
4061         wfRestoreWarnings();
4062
4063         if ( $result === false ) {
4064                 // If it cannot extract the packed data.
4065                 throw new MWException( "unpack could not unpack binary data" );
4066         }
4067         return $result;
4068 }
4069
4070 /**
4071  * Determine if an image exists on the 'bad image list'.
4072  *
4073  * The format of MediaWiki:Bad_image_list is as follows:
4074  *    * Only list items (lines starting with "*") are considered
4075  *    * The first link on a line must be a link to a bad image
4076  *    * Any subsequent links on the same line are considered to be exceptions,
4077  *      i.e. articles where the image may occur inline.
4078  *
4079  * @param string $name the image name to check
4080  * @param $contextTitle Title|bool the page on which the image occurs, if known
4081  * @param string $blacklist wikitext of a file blacklist
4082  * @return bool
4083  */
4084 function wfIsBadImage( $name, $contextTitle = false, $blacklist = null ) {
4085         static $badImageCache = null; // based on bad_image_list msg
4086         wfProfileIn( __METHOD__ );
4087
4088         # Handle redirects
4089         $redirectTitle = RepoGroup::singleton()->checkRedirect( Title::makeTitle( NS_FILE, $name ) );
4090         if ( $redirectTitle ) {
4091                 $name = $redirectTitle->getDBkey();
4092         }
4093
4094         # Run the extension hook
4095         $bad = false;
4096         if ( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
4097                 wfProfileOut( __METHOD__ );
4098                 return $bad;
4099         }
4100
4101         $cacheable = ( $blacklist === null );
4102         if ( $cacheable && $badImageCache !== null ) {
4103                 $badImages = $badImageCache;
4104         } else { // cache miss
4105                 if ( $blacklist === null ) {
4106                         $blacklist = wfMessage( 'bad_image_list' )->inContentLanguage()->plain(); // site list
4107                 }
4108                 # Build the list now
4109                 $badImages = array();
4110                 $lines = explode( "\n", $blacklist );
4111                 foreach ( $lines as $line ) {
4112                         # List items only
4113                         if ( substr( $line, 0, 1 ) !== '*' ) {
4114                                 continue;
4115                         }
4116
4117                         # Find all links
4118                         $m = array();
4119                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
4120                                 continue;
4121                         }
4122
4123                         $exceptions = array();
4124                         $imageDBkey = false;
4125                         foreach ( $m[1] as $i => $titleText ) {
4126                                 $title = Title::newFromText( $titleText );
4127                                 if ( !is_null( $title ) ) {
4128                                         if ( $i == 0 ) {
4129                                                 $imageDBkey = $title->getDBkey();
4130                                         } else {
4131                                                 $exceptions[$title->getPrefixedDBkey()] = true;
4132                                         }
4133                                 }
4134                         }
4135
4136                         if ( $imageDBkey !== false ) {
4137                                 $badImages[$imageDBkey] = $exceptions;
4138                         }
4139                 }
4140                 if ( $cacheable ) {
4141                         $badImageCache = $badImages;
4142                 }
4143         }
4144
4145         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
4146         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
4147         wfProfileOut( __METHOD__ );
4148         return $bad;
4149 }
4150
4151 /**
4152  * Determine whether the client at a given source IP is likely to be able to
4153  * access the wiki via HTTPS.
4154  *
4155  * @param string $ip The IPv4/6 address in the normal human-readable form
4156  * @return boolean
4157  */
4158 function wfCanIPUseHTTPS( $ip ) {
4159         $canDo = true;
4160         wfRunHooks( 'CanIPUseHTTPS', array( $ip, &$canDo ) );
4161         return !!$canDo;
4162 }
4163
4164 /**
4165  * Work out the IP address based on various globals
4166  * For trusted proxies, use the XFF client IP (first of the chain)
4167  *
4168  * @deprecated in 1.19; call $wgRequest->getIP() directly.
4169  * @return string
4170  */
4171 function wfGetIP() {
4172         wfDeprecated( __METHOD__, '1.19' );
4173         global $wgRequest;
4174         return $wgRequest->getIP();
4175 }
4176
4177 /**
4178  * Checks if an IP is a trusted proxy provider.
4179  * Useful to tell if X-Forwarded-For data is possibly bogus.
4180  * Squid cache servers for the site are whitelisted.
4181  *
4182  * @param $ip String
4183  * @return bool
4184  */
4185 function wfIsTrustedProxy( $ip ) {
4186         $trusted = wfIsConfiguredProxy( $ip );
4187         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
4188         return $trusted;
4189 }
4190
4191 /**
4192  * Checks if an IP matches a proxy we've configured.
4193  * @param $ip String
4194  * @return bool
4195  * @since 1.23 Supports CIDR ranges in $wgSquidServersNoPurge
4196  */
4197 function wfIsConfiguredProxy( $ip ) {
4198         global $wgSquidServers, $wgSquidServersNoPurge;
4199
4200         // quick check of known proxy servers
4201         $trusted = in_array( $ip, $wgSquidServers )
4202                 || in_array( $ip, $wgSquidServersNoPurge );
4203
4204         if ( !$trusted ) {
4205                 // slightly slower check to see if the ip is listed directly or in a CIDR
4206                 // block in $wgSquidServersNoPurge
4207                 foreach ( $wgSquidServersNoPurge as $block ) {
4208                         if ( strpos( $block, '/' ) !== false && IP::isInRange( $ip, $block ) ) {
4209                                 $trusted = true;
4210                                 break;
4211                         }
4212                 }
4213         }
4214         return $trusted;
4215 }