/includes/GlobalFunctions.php

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<?php
/**
 * Global functions used everywhere
 * @file
 */

if ( !defined( 'MEDIAWIKI' ) ) {
	die( "This file is part of MediaWiki, it is not a valid entry point" );
}

// Hide compatibility functions from Doxygen
/// @cond

/**
 * Compatibility functions
 *
 * We support PHP 5.2.3 and up.
 * Re-implementations of newer functions or functions in non-standard
 * PHP extensions may be included here.
 */

if( !function_exists( 'iconv' ) ) {
	/** @codeCoverageIgnore */
	function iconv( $from, $to, $string ) {
		return Fallback::iconv( $from, $to, $string );
	}
}

if ( !function_exists( 'mb_substr' ) ) {
	/** @codeCoverageIgnore */
	function mb_substr( $str, $start, $count='end' ) {
		return Fallback::mb_substr( $str, $start, $count );
	}

	/** @codeCoverageIgnore */
	function mb_substr_split_unicode( $str, $splitPos ) {
		return Fallback::mb_substr_split_unicode( $str, $splitPos );
	}
}

if ( !function_exists( 'mb_strlen' ) ) {
	/** @codeCoverageIgnore */
	function mb_strlen( $str, $enc = '' ) {
		return Fallback::mb_strlen( $str, $enc );
	}
}

if( !function_exists( 'mb_strpos' ) ) {
	/** @codeCoverageIgnore */
	function mb_strpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
		return Fallback::mb_strpos( $haystack, $needle, $offset, $encoding );
	}

}

if( !function_exists( 'mb_strrpos' ) ) {
	/** @codeCoverageIgnore */
	function mb_strrpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
		return Fallback::mb_strrpos( $haystack, $needle, $offset, $encoding );
	}
}


// Support for Wietse Venema's taint feature
if ( !function_exists( 'istainted' ) ) {
	/** @codeCoverageIgnore */
	function istainted( $var ) {
		return 0;
	}
	/** @codeCoverageIgnore */
	function taint( $var, $level = 0 ) {}
	/** @codeCoverageIgnore */
	function untaint( $var, $level = 0 ) {}
	define( 'TC_HTML', 1 );
	define( 'TC_SHELL', 1 );
	define( 'TC_MYSQL', 1 );
	define( 'TC_PCRE', 1 );
	define( 'TC_SELF', 1 );
}
/// @endcond

/**
 * Like array_diff( $a, $b ) except that it works with two-dimensional arrays.
 * @param $a array
 * @param $b array
 * @return array
 */
function wfArrayDiff2( $a, $b ) {
	return array_udiff( $a, $b, 'wfArrayDiff2_cmp' );
}

/**
 * @param $a
 * @param $b
 * @return int
 */
function wfArrayDiff2_cmp( $a, $b ) {
	if ( !is_array( $a ) ) {
		return strcmp( $a, $b );
	} elseif ( count( $a ) !== count( $b ) ) {
		return count( $a ) < count( $b ) ? -1 : 1;
	} else {
		reset( $a );
		reset( $b );
		while( ( list( , $valueA ) = each( $a ) ) && ( list( , $valueB ) = each( $b ) ) ) {
			$cmp = strcmp( $valueA, $valueB );
			if ( $cmp !== 0 ) {
				return $cmp;
			}
		}
		return 0;
	}
}

/**
 * Array lookup
 * Returns an array where the values in the first array are replaced by the
 * values in the second array with the corresponding keys
 *
 * @param $a Array
 * @param $b Array
 * @return array
 */
function wfArrayLookup( $a, $b ) {
	return array_flip( array_intersect( array_flip( $a ), array_keys( $b ) ) );
}

/**
 * Appends to second array if $value differs from that in $default
 *
 * @param $key String|Int
 * @param $value Mixed
 * @param $default Mixed
 * @param $changed Array to alter
 */
function wfAppendToArrayIfNotDefault( $key, $value, $default, &$changed ) {
	if ( is_null( $changed ) ) {
		throw new MWException( 'GlobalFunctions::wfAppendToArrayIfNotDefault got null' );
	}
	if ( $default[$key] !== $value ) {
		$changed[$key] = $value;
	}
}

/**
 * Backwards array plus for people who haven't bothered to read the PHP manual
 * XXX: will not darn your socks for you.
 *
 * @param $array1 Array
 * @param [$array2, [...]] Arrays
 * @return Array
 */
function wfArrayMerge( $array1/* ... */ ) {
	$args = func_get_args();
	$args = array_reverse( $args, true );
	$out = array();
	foreach ( $args as $arg ) {
		$out += $arg;
	}
	return $out;
}

/**
 * Merge arrays in the style of getUserPermissionsErrors, with duplicate removal
 * e.g.
 *	wfMergeErrorArrays(
 *		array( array( 'x' ) ),
 *		array( array( 'x', '2' ) ),
 *		array( array( 'x' ) ),
 *		array( array( 'y' ) )
 *	);
 * returns:
 * 		array(
 *   		array( 'x', '2' ),
 *   		array( 'x' ),
 *   		array( 'y' )
 *   	)
 * @param varargs
 * @return Array
 */
function wfMergeErrorArrays( /*...*/ ) {
	$args = func_get_args();
	$out = array();
	foreach ( $args as $errors ) {
		foreach ( $errors as $params ) {
			# @todo FIXME: Sometimes get nested arrays for $params,
			# which leads to E_NOTICEs
			$spec = implode( "\t", $params );
			$out[$spec] = $params;
		}
	}
	return array_values( $out );
}

/**
 * Insert array into another array after the specified *KEY*
 *
 * @param $array Array: The array.
 * @param $insert Array: The array to insert.
 * @param $after Mixed: The key to insert after
 * @return Array
 */
function wfArrayInsertAfter( $array, $insert, $after ) {
	// Find the offset of the element to insert after.
	$keys = array_keys( $array );
	$offsetByKey = array_flip( $keys );

	$offset = $offsetByKey[$after];

	// Insert at the specified offset
	$before = array_slice( $array, 0, $offset + 1, true );
	$after = array_slice( $array, $offset + 1, count( $array ) - $offset, true );

	$output = $before + $insert + $after;

	return $output;
}

/**
 * Recursively converts the parameter (an object) to an array with the same data
 *
 * @param $objOrArray Object|Array
 * @param $recursive Bool
 * @return Array
 */
function wfObjectToArray( $objOrArray, $recursive = true ) {
	$array = array();
	if( is_object( $objOrArray ) ) {
		$objOrArray = get_object_vars( $objOrArray );
	}
	foreach ( $objOrArray as $key => $value ) {
		if ( $recursive && ( is_object( $value ) || is_array( $value ) ) ) {
			$value = wfObjectToArray( $value );
		}

		$array[$key] = $value;
	}

	return $array;
}

/**
 * Wrapper around array_map() which also taints variables
 *
 * @param  $function Callback
 * @param  $input Array
 * @return Array
 */
function wfArrayMap( $function, $input ) {
	$ret = array_map( $function, $input );
	foreach ( $ret as $key => $value ) {
		$taint = istainted( $input[$key] );
		if ( $taint ) {
			taint( $ret[$key], $taint );
		}
	}
	return $ret;
}

/**
 * Get a random decimal value between 0 and 1, in a way
 * not likely to give duplicate values for any realistic
 * number of articles.
 *
 * @return string
 */
function wfRandom() {
	# The maximum random value is "only" 2^31-1, so get two random
	# values to reduce the chance of dupes
	$max = mt_getrandmax() + 1;
	$rand = number_format( ( mt_rand() * $max + mt_rand() )
		/ $max / $max, 12, '.', '' );
	return $rand;
}

/**
 * We want some things to be included as literal characters in our title URLs
 * for prettiness, which urlencode encodes by default.  According to RFC 1738,
 * all of the following should be safe:
 *
 * ;:@&=$-_.+!*'(),
 *
 * But + is not safe because it's used to indicate a space; &= are only safe in
 * paths and not in queries (and we don't distinguish here); ' seems kind of
 * scary; and urlencode() doesn't touch -_. to begin with.  Plus, although /
 * is reserved, we don't care.  So the list we unescape is:
 *
 * ;:@$!*(),/
 *
 * However, IIS7 redirects fail when the url contains a colon (Bug 22709),
 * so no fancy : for IIS7.
 *
 * %2F in the page titles seems to fatally break for some reason.
 *
 * @param $s String:
 * @return string
*/
function wfUrlencode( $s ) {
	static $needle;
	if ( is_null( $s ) ) {
		$needle = null;
		return '';
	}

	if ( is_null( $needle ) ) {
		$needle = array( '%3B', '%40', '%24', '%21', '%2A', '%28', '%29', '%2C', '%2F' );
		if ( !isset( $_SERVER['SERVER_SOFTWARE'] ) || ( strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/7' ) === false ) ) {
			$needle[] = '%3A';
		}
	}

	$s = urlencode( $s );
	$s = str_ireplace(
		$needle,
		array( ';', '@', '$', '!', '*', '(', ')', ',', '/', ':' ),
		$s
	);

	return $s;
}

/**
 * This function takes two arrays as input, and returns a CGI-style string, e.g.
 * "days=7&limit=100". Options in the first array override options in the second.
 * Options set to null or false will not be output.
 *
 * @param $array1 Array ( String|Array )
 * @param $array2 Array ( String|Array )
 * @param $prefix String
 * @return String
 */
function wfArrayToCGI( $array1, $array2 = null, $prefix = '' ) {
	if ( !is_null( $array2 ) ) {
		$array1 = $array1 + $array2;
	}

	$cgi = '';
	foreach ( $array1 as $key => $value ) {
		if ( !is_null($value) && $value !== false ) {
			if ( $cgi != '' ) {
				$cgi .= '&';
			}
			if ( $prefix !== '' ) {
				$key = $prefix . "[$key]";
			}
			if ( is_array( $value ) ) {
				$firstTime = true;
				foreach ( $value as $k => $v ) {
					$cgi .= $firstTime ? '' : '&';
					if ( is_array( $v ) ) {
						$cgi .= wfArrayToCGI( $v, null, $key . "[$k]" );
					} else {
						$cgi .= urlencode( $key . "[$k]" ) . '=' . urlencode( $v );
					}
					$firstTime = false;
				}
			} else {
				if ( is_object( $value ) ) {
					$value = $value->__toString();
				}
				$cgi .= urlencode( $key ) . '=' . urlencode( $value );
			}
		}
	}
	return $cgi;
}

/**
 * This is the logical opposite of wfArrayToCGI(): it accepts a query string as
 * its argument and returns the same string in array form.  This allows compa-
 * tibility with legacy functions that accept raw query strings instead of nice
 * arrays.  Of course, keys and values are urldecode()d.
 *
 * @param $query String: query string
 * @return array Array version of input
 */
function wfCgiToArray( $query ) {
	if ( isset( $query[0] ) && $query[0] == '?' ) {
		$query = substr( $query, 1 );
	}
	$bits = explode( '&', $query );
	$ret = array();
	foreach ( $bits as $bit ) {
		if ( $bit === '' ) {
			continue;
		}
		if ( strpos( $bit, '=' ) === false ) {
			// Pieces like &qwerty become 'qwerty' => '' (at least this is what php does)
			$key = $bit;
			$value = '';
		} else {
			list( $key, $value ) = explode( '=', $bit );
		}
		$key = urldecode( $key );
		$value = urldecode( $value );
		if ( strpos( $key, '[' ) !== false ) {
			$keys = array_reverse( explode( '[', $key ) );
			$key = array_pop( $keys );
			$temp = $value;
			foreach ( $keys as $k ) {
				$k = substr( $k, 0, -1 );
				$temp = array( $k => $temp );
			}
			if ( isset( $ret[$key] ) ) {
				$ret[$key] = array_merge( $ret[$key], $temp );
			} else {
				$ret[$key] = $temp;
			}
		} else {
			$ret[$key] = $value;
		}
	}
	return $ret;
}

/**
 * Append a query string to an existing URL, which may or may not already
 * have query string parameters already. If so, they will be combined.
 *
 * @param $url String
 * @param $query Mixed: string or associative array
 * @return string
 */
function wfAppendQuery( $url, $query ) {
	if ( is_array( $query ) ) {
		$query = wfArrayToCGI( $query );
	}
	if( $query != '' ) {
		if( false === strpos( $url, '?' ) ) {
			$url .= '?';
		} else {
			$url .= '&';
		}
		$url .= $query;
	}
	return $url;
}

/**
 * Expand a potentially local URL to a fully-qualified URL.  Assumes $wgServer
 * is correct.
 *
 * The meaning of the PROTO_* constants is as follows:
 * PROTO_HTTP: Output a URL starting with http://
 * PROTO_HTTPS: Output a URL starting with https://
 * PROTO_RELATIVE: Output a URL starting with // (protocol-relative URL)
 * PROTO_CURRENT: Output a URL starting with either http:// or https:// , depending on which protocol was used for the current incoming request
 * PROTO_CANONICAL: For URLs without a domain, like /w/index.php , use $wgCanonicalServer. For protocol-relative URLs, use the protocol of $wgCanonicalServer
 * PROTO_INTERNAL: Like PROTO_CANONICAL, but uses $wgInternalServer instead of $wgCanonicalServer
 *
 * @todo this won't work with current-path-relative URLs
 * like "subdir/foo.html", etc.
 *
 * @param $url String: either fully-qualified or a local path + query
 * @param $defaultProto Mixed: one of the PROTO_* constants. Determines the
 *                             protocol to use if $url or $wgServer is
 *                             protocol-relative
 * @return string Fully-qualified URL, current-path-relative URL or false if
 *                no valid URL can be constructed
 */
function wfExpandUrl( $url, $defaultProto = PROTO_CURRENT ) {
	global $wgServer, $wgCanonicalServer, $wgInternalServer;
	$serverUrl = $wgServer;
	if ( $defaultProto === PROTO_CANONICAL ) {
		$serverUrl = $wgCanonicalServer;
	}
	// Make $wgInternalServer fall back to $wgServer if not set
	if ( $defaultProto === PROTO_INTERNAL && $wgInternalServer !== false ) {
		$serverUrl = $wgInternalServer;
	}
	if ( $defaultProto === PROTO_CURRENT ) {
		$defaultProto = WebRequest::detectProtocol() . '://';
	}

	// Analyze $serverUrl to obtain its protocol
	$bits = wfParseUrl( $serverUrl );
	$serverHasProto = $bits && $bits['scheme'] != '';

	if ( $defaultProto === PROTO_CANONICAL || $defaultProto === PROTO_INTERNAL ) {
		if ( $serverHasProto ) {
			$defaultProto = $bits['scheme'] . '://';
		} else {
			// $wgCanonicalServer or $wgInternalServer doesn't have a protocol. This really isn't supposed to happen
			// Fall back to HTTP in this ridiculous case
			$defaultProto = PROTO_HTTP;
		}
	}

	$defaultProtoWithoutSlashes = substr( $defaultProto, 0, -2 );

	if ( substr( $url, 0, 2 ) == '//' ) {
		$url = $defaultProtoWithoutSlashes . $url;
	} elseif ( substr( $url, 0, 1 ) == '/' ) {
		// If $serverUrl is protocol-relative, prepend $defaultProtoWithoutSlashes, otherwise leave it alone
		$url = ( $serverHasProto ? '' : $defaultProtoWithoutSlashes ) . $serverUrl . $url;
	}

	$bits = wfParseUrl( $url );
	if ( $bits && isset( $bits['path'] ) ) {
		$bits['path'] = wfRemoveDotSegments( $bits['path'] );
		return wfAssembleUrl( $bits );
	} elseif ( $bits ) {
		# No path to expand
		return $url;
	} elseif ( substr( $url, 0, 1 ) != '/' ) {
		# URL is a relative path
		return wfRemoveDotSegments( $url );
	}

	# Expanded URL is not valid.
	return false;
}

/**
 * This function will reassemble a URL parsed with wfParseURL.  This is useful
 * if you need to edit part of a URL and put it back together.
 *
 * This is the basic structure used (brackets contain keys for $urlParts):
 * [scheme][delimiter][user]:[pass]@[host]:[port][path]?[query]#[fragment]
 *
 * @todo Need to integrate this into wfExpandUrl (bug 32168)
 *
 * @since 1.19
 * @param $urlParts Array URL parts, as output from wfParseUrl
 * @return string URL assembled from its component parts
 */
function wfAssembleUrl( $urlParts ) {
	$result = '';

	if ( isset( $urlParts['delimiter'] ) ) {
		if ( isset( $urlParts['scheme'] ) ) {
			$result .= $urlParts['scheme'];
		}

		$result .= $urlParts['delimiter'];
	}

	if ( isset( $urlParts['host'] ) ) {
		if ( isset( $urlParts['user'] ) ) {
			$result .= $urlParts['user'];
			if ( isset( $urlParts['pass'] ) ) {
				$result .= ':' . $urlParts['pass'];
			}
			$result .= '@';
		}

		$result .= $urlParts['host'];

		if ( isset( $urlParts['port'] ) ) {
			$result .= ':' . $urlParts['port'];
		}
	}

	if ( isset( $urlParts['path'] ) ) {
		$result .= $urlParts['path'];
	}

	if ( isset( $urlParts['query'] ) ) {
		$result .= '?' . $urlParts['query'];
	}

	if ( isset( $urlParts['fragment'] ) ) {
		$result .= '#' . $urlParts['fragment'];
	}

	return $result;
}

/**
 * Remove all dot-segments in the provided URL path.  For example,
 * '/a/./b/../c/' becomes '/a/c/'.  For details on the algorithm, please see
 * RFC3986 section 5.2.4.
 *
 * @todo Need to integrate this into wfExpandUrl (bug 32168)
 *
 * @param $urlPath String URL path, potentially containing dot-segments
 * @return string URL path with all dot-segments removed
 */
function wfRemoveDotSegments( $urlPath ) {
	$output = '';
	$inputOffset = 0;
	$inputLength = strlen( $urlPath );

	while ( $inputOffset < $inputLength ) {
		$prefixLengthOne = substr( $urlPath, $inputOffset, 1 );
		$prefixLengthTwo = substr( $urlPath, $inputOffset, 2 );
		$prefixLengthThree = substr( $urlPath, $inputOffset, 3 );
		$prefixLengthFour = substr( $urlPath, $inputOffset, 4 );
		$trimOutput = false;

		if ( $prefixLengthTwo == './' ) {
			# Step A, remove leading "./"
			$inputOffset += 2;
		} elseif ( $prefixLengthThree == '../' ) {
			# Step A, remove leading "../"
			$inputOffset += 3;
		} elseif ( ( $prefixLengthTwo == '/.' ) && ( $inputOffset + 2 == $inputLength ) ) {
			# Step B, replace leading "/.$" with "/"
			$inputOffset += 1;
			$urlPath[$inputOffset] = '/';
		} elseif ( $prefixLengthThree == '/./' ) {
			# Step B, replace leading "/./" with "/"
			$inputOffset += 2;
		} elseif ( $prefixLengthThree == '/..' && ( $inputOffset + 3 == $inputLength ) ) {
			# Step C, replace leading "/..$" with "/" and
			# remove last path component in output
			$inputOffset += 2;
			$urlPath[$inputOffset] = '/';
			$trimOutput = true;
		} elseif ( $prefixLengthFour == '/../' ) {
			# Step C, replace leading "/../" with "/" and
			# remove last path component in output
			$inputOffset += 3;
			$trimOutput = true;
		} elseif ( ( $prefixLengthOne == '.' ) && ( $inputOffset + 1 == $inputLength ) ) {
			# Step D, remove "^.$"
			$inputOffset += 1;
		} elseif ( ( $prefixLengthTwo == '..' ) && ( $inputOffset + 2 == $inputLength ) ) {
			# Step D, remove "^..$"
			$inputOffset += 2;
		} else {
			# Step E, move leading path segment to output
			if ( $prefixLengthOne == '/' ) {
				$slashPos = strpos( $urlPath, '/', $inputOffset + 1 );
			} else {
				$slashPos = strpos( $urlPath, '/', $inputOffset );
			}
			if ( $slashPos === false ) {
				$output .= substr( $urlPath, $inputOffset );
				$inputOffset = $inputLength;
			} else {
				$output .= substr( $urlPath, $inputOffset, $slashPos - $inputOffset );
				$inputOffset += $slashPos - $inputOffset;
			}
		}

		if ( $trimOutput ) {
			$slashPos = strrpos( $output, '/' );
			if ( $slashPos === false ) {
				$output = '';
			} else {
				$output = substr( $output, 0, $slashPos );
			}
		}
	}

	return $output;
}

/**
 * Returns a regular expression of url protocols
 *
 * @param $includeProtocolRelative bool If false, remove '//' from the returned protocol list.
 *        DO NOT USE this directly, use wfUrlProtocolsWithoutProtRel() instead
 * @return String
 */
function wfUrlProtocols( $includeProtocolRelative = true ) {
	global $wgUrlProtocols;

	// Cache return values separately based on $includeProtocolRelative
	static $withProtRel = null, $withoutProtRel = null;
	$cachedValue = $includeProtocolRelative ? $withProtRel : $withoutProtRel;
	if ( !is_null( $cachedValue ) ) {
		return $cachedValue;
	}

	// Support old-style $wgUrlProtocols strings, for backwards compatibility
	// with LocalSettings files from 1.5
	if ( is_array( $wgUrlProtocols ) ) {
		$protocols = array();
		foreach ( $wgUrlProtocols as $protocol ) {
			// Filter out '//' if !$includeProtocolRelative
			if ( $includeProtocolRelative || $protocol !== '//' ) {
				$protocols[] = preg_quote( $protocol, '/' );
			}
		}

		$retval = implode( '|', $protocols );
	} else {
		// Ignore $includeProtocolRelative in this case
		// This case exists for pre-1.6 compatibility, and we can safely assume
		// that '//' won't appear in a pre-1.6 config because protocol-relative
		// URLs weren't supported until 1.18
		$retval = $wgUrlProtocols;
	}

	// Cache return value
	if ( $includeProtocolRelative ) {
		$withProtRel = $retval;
	} else {
		$withoutProtRel = $retval;
	}
	return $retval;
}

/**
 * Like wfUrlProtocols(), but excludes '//' from the protocol list. Use this if
 * you need a regex that matches all URL protocols but does not match protocol-
 * relative URLs
 * @return String
 */
function wfUrlProtocolsWithoutProtRel() {
	return wfUrlProtocols( false );
}

/**
 * parse_url() work-alike, but non-broken.  Differences:
 *
 * 1) Does not raise warnings on bad URLs (just returns false)
 * 2) Handles protocols that don't use :// (e.g., mailto: and news: , as well as protocol-relative URLs) correctly
 * 3) Adds a "delimiter" element to the array, either '://', ':' or '//' (see (2))
 *
 * @param $url String: a URL to parse
 * @return Array: bits of the URL in an associative array, per PHP docs
 */
function wfParseUrl( $url ) {
	global $wgUrlProtocols; // Allow all protocols defined in DefaultSettings/LocalSettings.php

	// Protocol-relative URLs are handled really badly by parse_url(). It's so bad that the easiest
	// way to handle them is to just prepend 'http:' and strip the protocol out later
	$wasRelative = substr( $url, 0, 2 ) == '//';
	if ( $wasRelative ) {
		$url = "http:$url";
	}
	wfSuppressWarnings();
	$bits = parse_url( $url );
	wfRestoreWarnings();
	// parse_url() returns an array without scheme for some invalid URLs, e.g.
	// parse_url("%0Ahttp://example.com") == array( 'host' => '%0Ahttp', 'path' => 'example.com' )
	if ( !$bits || !isset( $bits['scheme'] ) ) {
		return false;
	}

	// most of the protocols are followed by ://, but mailto: and sometimes news: not, check for it
	if ( in_array( $bits['scheme'] . '://', $wgUrlProtocols ) ) {
		$bits['delimiter'] = '://';
	} elseif ( in_array( $bits['scheme'] . ':', $wgUrlProtocols ) ) {
		$bits['delimiter'] = ':';
		// parse_url detects for news: and mailto: the host part of an url as path
		// We have to correct this wrong detection
		if ( isset( $bits['path'] ) ) {
			$bits['host'] = $bits['path'];
			$bits['path'] = '';
		}
	} else {
		return false;
	}

	/* Provide an empty host for eg. file:/// urls (see bug 28627) */
	if ( !isset( $bits['host'] ) ) {
		$bits['host'] = '';

		/* parse_url loses the third / for file:///c:/ urls (but not on variants) */
		if ( substr( $bits['path'], 0, 1 ) !== '/' ) {
			$bits['path'] = '/' . $bits['path'];
		}
	}

	// If the URL was protocol-relative, fix scheme and delimiter
	if ( $wasRelative ) {
		$bits['scheme'] = '';
		$bits['delimiter'] = '//';
	}
	return $bits;
}

/**
 * Make URL indexes, appropriate for the el_index field of externallinks.
 *
 * @param $url String
 * @return array
 */
function wfMakeUrlIndexes( $url ) {
	$bits = wfParseUrl( $url );

	// Reverse the labels in the hostname, convert to lower case
	// For emails reverse domainpart only
	if ( $bits['scheme'] == 'mailto' ) {
		$mailparts = explode( '@', $bits['host'], 2 );
		if ( count( $mailparts ) === 2 ) {
			$domainpart = strtolower( implode( '.', array_reverse( explode( '.', $mailparts[1] ) ) ) );
		} else {
			// No domain specified, don't mangle it
			$domainpart = '';
		}
		$reversedHost = $domainpart . '@' . $mailparts[0];
	} else {
		$reversedHost = strtolower( implode( '.', array_reverse( explode( '.', $bits['host'] ) ) ) );
	}
	// Add an extra dot to the end
	// Why? Is it in wrong place in mailto links?
	if ( substr( $reversedHost, -1, 1 ) !== '.' ) {
		$reversedHost .= '.';
	}
	// Reconstruct the pseudo-URL
	$prot = $bits['scheme'];
	$index = $prot . $bits['delimiter'] . $reversedHost;
	// Leave out user and password. Add the port, path, query and fragment
	if ( isset( $bits['port'] ) ) {
		$index .= ':' . $bits['port'];
	}
	if ( isset( $bits['path'] ) ) {
		$index .= $bits['path'];
	} else {
		$index .= '/';
	}
	if ( isset( $bits['query'] ) ) {
		$index .= '?' . $bits['query'];
	}
	if ( isset( $bits['fragment'] ) ) {
		$index .= '#' . $bits['fragment'];
	}

	if ( $prot == '' ) {
		return array( "http:$index", "https:$index" );
	} else {
		return array( $index );
	}
}

/**
 * Check whether a given URL has a domain that occurs in a given set of domains
 * @param $url string URL
 * @param $domains array Array of domains (strings)
 * @return bool True if the host part of $url ends in one of the strings in $domains
 */
function wfMatchesDomainList( $url, $domains ) {
	$bits = wfParseUrl( $url );
	if ( is_array( $bits ) && isset( $bits['host'] ) ) {
		foreach ( (array)$domains as $domain ) {
			// FIXME: This gives false positives. http://nds-nl.wikipedia.org will match nl.wikipedia.org
			// We should use something that interprets dots instead
			if ( substr( $bits['host'], -strlen( $domain ) ) === $domain ) {
				return true;
			}
		}
	}
	return false;
}

/**
 * Sends a line to the debug log if enabled or, optionally, to a comment in output.
 * In normal operation this is a NOP.
 *
 * Controlling globals:
 * $wgDebugLogFile - points to the log file
 * $wgProfileOnly - if set, normal debug messages will not be recorded.
 * $wgDebugRawPage - if false, 'action=raw' hits will not result in debug output.
 * $wgDebugComments - if on, some debug items may appear in comments in the HTML output.
 *
 * @param $text String
 * @param $logonly Bool: set true to avoid appearing in HTML when $wgDebugComments is set
 */
function wfDebug( $text, $logonly = false ) {
	global $wgOut, $wgDebugLogFile, $wgDebugComments, $wgProfileOnly, $wgDebugRawPage;
	global $wgDebugLogPrefix, $wgShowDebug;

	static $cache = array(); // Cache of unoutputted messages
	$text = wfDebugTimer() . $text;

	if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
		return;
	}

	if ( ( $wgDebugComments || $wgShowDebug ) && !$logonly ) {
		$cache[] = $text;

		if ( isset( $wgOut ) && is_object( $wgOut ) ) {
			// add the message and any cached messages to the output
			array_map( array( $wgOut, 'debug' ), $cache );
			$cache = array();
		}
	}
	if ( wfRunHooks( 'Debug', array( $text, null /* no log group */ ) ) ) {
		if ( $wgDebugLogFile != '' && !$wgProfileOnly ) {
			# Strip unprintables; they can switch terminal modes when binary data
			# gets dumped, which is pretty annoying.
			$text = preg_replace( '![\x00-\x08\x0b\x0c\x0e-\x1f]!', ' ', $text );
			$text = $wgDebugLogPrefix . $text;
			wfErrorLog( $text, $wgDebugLogFile );
		}
	}

	MWDebug::debugMsg( $text );
}

/**
 * Returns true if debug logging should be suppressed if $wgDebugRawPage = false
 */
function wfIsDebugRawPage() {
	static $cache;
	if ( $cache !== null ) {
		return $cache;
	}
	# Check for raw action using $_GET not $wgRequest, since the latter might not be initialised yet
	if ( ( isset( $_GET['action'] ) && $_GET['action'] == 'raw' )
		|| (
			isset( $_SERVER['SCRIPT_NAME'] )
			&& substr( $_SERVER['SCRIPT_NAME'], -8 ) == 'load.php'
		) )
	{
		$cache = true;
	} else {
		$cache = false;
	}
	return $cache;
}

/**
 * Get microsecond timestamps for debug logs
 *
 * @return string
 */
function wfDebugTimer() {
	global $wgDebugTimestamps, $wgRequestTime;

	if ( !$wgDebugTimestamps ) {
		return '';
	}

	$prefix = sprintf( "%6.4f", microtime( true ) - $wgRequestTime );
	$mem = sprintf( "%5.1fM", ( memory_get_usage( true ) / ( 1024 * 1024 ) ) );
	return "$prefix $mem  ";
}

/**
 * Send a line giving PHP memory usage.
 *
 * @param $exact Bool: print exact values instead of kilobytes (default: false)
 */
function wfDebugMem( $exact = false ) {
	$mem = memory_get_usage();
	if( !$exact ) {
		$mem = floor( $mem / 1024 ) . ' kilobytes';
	} else {
		$mem .= ' bytes';
	}
	wfDebug( "Memory usage: $mem\n" );
}

/**
 * Send a line to a supplementary debug log file, if configured, or main debug log if not.
 * $wgDebugLogGroups[$logGroup] should be set to a filename to send to a separate log.
 *
 * @param $logGroup String
 * @param $text String
 * @param $public Bool: whether to log the event in the public log if no private
 *                     log file is specified, (default true)
 */
function wfDebugLog( $logGroup, $text, $public = true ) {
	global $wgDebugLogGroups;
	$text = trim( $text ) . "\n";
	if( isset( $wgDebugLogGroups[$logGroup] ) ) {
		$time = wfTimestamp( TS_DB );
		$wiki = wfWikiID();
		$host = wfHostname();
		if ( wfRunHooks( 'Debug', array( $text, $logGroup ) ) ) {
			wfErrorLog( "$time $host $wiki: $text", $wgDebugLogGroups[$logGroup] );
		}
	} elseif ( $public === true ) {
		wfDebug( $text, true );
	}
}

/**
 * Log for database errors
 *
 * @param $text String: database error message.
 */
function wfLogDBError( $text ) {
	global $wgDBerrorLog;
	if ( $wgDBerrorLog ) {
		$host = wfHostname();
		$wiki = wfWikiID();
		$text = date( 'D M j G:i:s T Y' ) . "\t$host\t$wiki\t$text";
		wfErrorLog( $text, $wgDBerrorLog );
	}
}

/**
 * Throws a warning that $function is deprecated
 *
 * @param $function String
 * @param $version String|false: Added in 1.19.
 * @param $component String|false: Added in 1.19.
 * 
 * @return null
 */
function wfDeprecated( $function, $version = false, $component = false ) {
	static $functionsWarned = array();

	MWDebug::deprecated( $function, $version, $component );

	if ( !isset( $functionsWarned[$function] ) ) {
		$functionsWarned[$function] = true;
		
		if ( $version ) {
			global $wgDeprecationReleaseLimit;
			
			if ( $wgDeprecationReleaseLimit && $component === false ) {
				# Strip -* off the end of $version so that branches can use the
				# format #.##-branchname to avoid issues if the branch is merged into
				# a version of MediaWiki later than what it was branched from
				$comparableVersion = preg_replace( '/-.*$/', '', $version );
				
				# If the comparableVersion is larger than our release limit then
				# skip the warning message for the deprecation
				if ( version_compare( $wgDeprecationReleaseLimit, $comparableVersion, '<' ) ) {
					return;
				}
			}
			
			$component = $component === false ? 'MediaWiki' : $component;
			wfWarn( "Use of $function was deprecated in $component $version.", 2 );
		} else {
			wfWarn( "Use of $function is deprecated.", 2 );
		}
	}
}

/**
 * Send a warning either to the debug log or in a PHP error depending on
 * $wgDevelopmentWarnings
 *
 * @param $msg String: message to send
 * @param $callerOffset Integer: number of items to go back in the backtrace to
 *        find the correct caller (1 = function calling wfWarn, ...)
 * @param $level Integer: PHP error level; only used when $wgDevelopmentWarnings
 *        is true
 */
function wfWarn( $msg, $callerOffset = 1, $level = E_USER_NOTICE ) {
	global $wgDevelopmentWarnings;

	MWDebug::warning( $msg, $callerOffset + 2 );

	$callers = wfDebugBacktrace();
	if ( isset( $callers[$callerOffset + 1] ) ) {
		$callerfunc = $callers[$callerOffset + 1];
		$callerfile = $callers[$callerOffset];
		if ( isset( $callerfile['file'] ) && isset( $callerfile['line'] ) ) {
			$file = $callerfile['file'] . ' at line ' . $callerfile['line'];
		} else {
			$file = '(internal function)';
		}
		$func = '';
		if ( isset( $callerfunc['class'] ) ) {
			$func .= $callerfunc['class'] . '::';
		}
		if ( isset( $callerfunc['function'] ) ) {
			$func .= $callerfunc['function'];
		}
		$msg .= " [Called from $func in $file]";
	}

	if ( $wgDevelopmentWarnings ) {
		trigger_error( $msg, $level );
	} else {
		wfDebug( "$msg\n" );
	}
}

/**
 * Log to a file without getting "file size exceeded" signals.
 *
 * Can also log to TCP or UDP with the syntax udp://host:port/prefix. This will
 * send lines to the specified port, prefixed by the specified prefix and a space.
 *
 * @param $text String
 * @param $file String filename
 */
function wfErrorLog( $text, $file ) {
	if ( substr( $file, 0, 4 ) == 'udp:' ) {
		# Needs the sockets extension
		if ( preg_match( '!^(tcp|udp):(?://)?\[([0-9a-fA-F:]+)\]:(\d+)(?:/(.*))?$!', $file, $m ) ) {
			// IPv6 bracketed host
			$host = $m[2];
			$port = intval( $m[3] );
			$prefix = isset( $m[4] ) ? $m[4] : false;
			$domain = AF_INET6;
		} elseif ( preg_match( '!^(tcp|udp):(?://)?([a-zA-Z0-9.-]+):(\d+)(?:/(.*))?$!', $file, $m ) ) {
			$host = $m[2];
			if ( !IP::isIPv4( $host ) ) {
				$host = gethostbyname( $host );
			}
			$port = intval( $m[3] );
			$prefix = isset( $m[4] ) ? $m[4] : false;
			$domain = AF_INET;
		} else {
			throw new MWException( __METHOD__ . ': Invalid UDP specification' );
		}

		// Clean it up for the multiplexer
		if ( strval( $prefix ) !== '' ) {
			$text = preg_replace( '/^/m', $prefix . ' ', $text );

			// Limit to 64KB
			if ( strlen( $text ) > 65506 ) {
				$text = substr( $text, 0, 65506 );
			}

			if ( substr( $text, -1 ) != "\n" ) {
				$text .= "\n";
			}
		} elseif ( strlen( $text ) > 65507 ) {
			$text = substr( $text, 0, 65507 );
		}

		$sock = socket_create( $domain, SOCK_DGRAM, SOL_UDP );
		if ( !$sock ) {
			return;
		}

		socket_sendto( $sock, $text, strlen( $text ), 0, $host, $port );
		socket_close( $sock );
	} else {
		wfSuppressWarnings();
		$exists = file_exists( $file );
		$size = $exists ? filesize( $file ) : false;
		if ( !$exists || ( $size !== false && $size + strlen( $text ) < 0x7fffffff ) ) {
			file_put_contents( $file, $text, FILE_APPEND );
		}
		wfRestoreWarnings();
	}
}

/**
 * @todo document
 */
function wfLogProfilingData() {
	global $wgRequestTime, $wgDebugLogFile, $wgDebugRawPage, $wgRequest;
	global $wgProfileLimit, $wgUser;

	$profiler = Profiler::instance();

	# Profiling must actually be enabled...
	if ( $profiler->isStub() ) {
		return;
	}

	// Get total page request time and only show pages that longer than
	// $wgProfileLimit time (default is 0)
	$elapsed = microtime( true ) - $wgRequestTime;
	if ( $elapsed <= $wgProfileLimit ) {
		return;
	}

	$profiler->logData();

	// Check whether this should be logged in the debug file.
	if ( $wgDebugLogFile == '' || ( !$wgDebugRawPage && wfIsDebugRawPage() ) ) {
		return;
	}

	$forward = '';
	if ( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
		$forward = ' forwarded for ' . $_SERVER['HTTP_X_FORWARDED_FOR'];
	}
	if ( !empty( $_SERVER['HTTP_CLIENT_IP'] ) ) {
		$forward .= ' client IP ' . $_SERVER['HTTP_CLIENT_IP'];
	}
	if ( !empty( $_SERVER['HTTP_FROM'] ) ) {
		$forward .= ' from ' . $_SERVER['HTTP_FROM'];
	}
	if ( $forward ) {
		$forward = "\t(proxied via {$_SERVER['REMOTE_ADDR']}{$forward})";
	}
	// Don't load $wgUser at this late stage just for statistics purposes
	// @todo FIXME: We can detect some anons even if it is not loaded. See User::getId()
	if ( $wgUser->isItemLoaded( 'id' ) && $wgUser->isAnon() ) {
		$forward .= ' anon';
	}
	$log = sprintf( "%s\t%04.3f\t%s\n",
		gmdate( 'YmdHis' ), $elapsed,
		urldecode( $wgRequest->getRequestURL() . $forward ) );

	wfErrorLog( $log . $profiler->getOutput(), $wgDebugLogFile );
}

/**
 * Check if the wiki read-only lock file is present. This can be used to lock
 * off editing functions, but doesn't guarantee that the database will not be
 * modified.
 *
 * @return bool
 */
function wfReadOnly() {
	global $wgReadOnlyFile, $wgReadOnly;

	if ( !is_null( $wgReadOnly ) ) {
		return (bool)$wgReadOnly;
	}
	if ( $wgReadOnlyFile == '' ) {
		return false;
	}
	// Set $wgReadOnly for faster access next time
	if ( is_file( $wgReadOnlyFile ) ) {
		$wgReadOnly = file_get_contents( $wgReadOnlyFile );
	} else {
		$wgReadOnly = false;
	}
	return (bool)$wgReadOnly;
}

/**
 * @return bool
 */
function wfReadOnlyReason() {
	global $wgReadOnly;
	wfReadOnly();
	return $wgReadOnly;
}

/**
 * Return a Language object from $langcode
 *
 * @param $langcode Mixed: either:
 *                  - a Language object
 *                  - code of the language to get the message for, if it is
 *                    a valid code create a language for that language, if
 *                    it is a string but not a valid code then make a basic
 *                    language object
 *                  - a boolean: if it's false then use the global object for
 *                    the current user's language (as a fallback for the old parameter
 *                    functionality), or if it is true then use global object
 *                    for the wiki's content language.
 * @return Language object
 */
function wfGetLangObj( $langcode = false ) {
	# Identify which language to get or create a language object for.
	# Using is_object here due to Stub objects.
	if( is_object( $langcode ) ) {
		# Great, we already have the object (hopefully)!
		return $langcode;
	}

	global $wgContLang, $wgLanguageCode;
	if( $langcode === true || $langcode === $wgLanguageCode ) {
		# $langcode is the language code of the wikis content language object.
		# or it is a boolean and value is true
		return $wgContLang;
	}

	global $wgLang;
	if( $langcode === false || $langcode === $wgLang->getCode() ) {
		# $langcode is the language code of user language object.
		# or it was a boolean and value is false
		return $wgLang;
	}

	$validCodes = array_keys( Language::getLanguageNames() );
	if( in_array( $langcode, $validCodes ) ) {
		# $langcode corresponds to a valid language.
		return Language::factory( $langcode );
	}

	# $langcode is a string, but not a valid language code; use content language.
	wfDebug( "Invalid language code passed to wfGetLangObj, falling back to content language.\n" );
	return $wgContLang;
}

/**
 * Old function when $wgBetterDirectionality existed
 * Removed in core, kept in extensions for backwards compat.
 *
 * @deprecated since 1.18
 * @return Language
 */
function wfUILang() {
	wfDeprecated( __METHOD__, '1.18' );
	global $wgLang;
	return $wgLang;
}

/**
 * This is the new function for getting translated interface messages.
 * See the Message class for documentation how to use them.
 * The intention is that this function replaces all old wfMsg* functions.
 * @param $key \string Message key.
 * Varargs: normal message parameters.
 * @return Message
 * @since 1.17
 */
function wfMessage( $key /*...*/) {
	$params = func_get_args();
	array_shift( $params );
	if ( isset( $params[0] ) && is_array( $params[0] ) ) {
		$params = $params[0];
	}
	return new Message( $key, $params );
}

/**
 * This function accepts multiple message keys and returns a message instance
 * for the first message which is non-empty. If all messages are empty then an
 * instance of the first message key is returned.
 * @param varargs: message keys
 * @return Message
 * @since 1.18
 */
function wfMessageFallback( /*...*/ ) {
	$args = func_get_args();
	return MWFunction::callArray( 'Message::newFallbackSequence', $args );
}

/**
 * Get a message from anywhere, for the current user language.
 *
 * Use wfMsgForContent() instead if the message should NOT
 * change depending on the user preferences.
 *
 * @param $key String: lookup key for the message, usually
 *    defined in languages/Language.php
 *
 * Parameters to the message, which can be used to insert variable text into
 * it, can be passed to this function in the following formats:
 * - One per argument, starting at the second parameter
 * - As an array in the second parameter
 * These are not shown in the function definition.
 *
 * @return String
 */
function wfMsg( $key ) {
	$args = func_get_args();
	array_shift( $args );
	return wfMsgReal( $key, $args );
}

/**
 * Same as above except doesn't transform the message
 *
 * @param $key String
 * @return String
 */
function wfMsgNoTrans( $key ) {
	$args = func_get_args();
	array_shift( $args );
	return wfMsgReal( $key, $args, true, false, false );
}

/**
 * Get a message from anywhere, for the current global language
 * set with $wgLanguageCode.
 *
 * Use this if the message should NOT change dependent on the
 * language set in the user's preferences. This is the case for
 * most text written into logs, as well as link targets (such as
 * the name of the copyright policy page). Link titles, on the
 * other hand, should be shown in the UI language.
 *
 * Note that MediaWiki allows users to change the user interface
 * language in their preferences, but a single installation
 * typically only contains content in one language.
 *
 * Be wary of this distinction: If you use wfMsg() where you should
 * use wfMsgForContent(), a user of the software may have to
 * customize potentially hundreds of messages in
 * order to, e.g., fix a link in every possible language.
 *
 * @param $key String: lookup key for the message, usually
 *     defined in languages/Language.php
 * @return String
 */
function wfMsgForContent( $key ) {
	global $wgForceUIMsgAsContentMsg;
	$args = func_get_args();
	array_shift( $args );
	$forcontent = true;
	if( is_array( $wgForceUIMsgAsContentMsg ) &&
		in_array( $key, $wgForceUIMsgAsContentMsg ) )
	{
		$forcontent = false;
	}
	return wfMsgReal( $key, $args, true, $forcontent );
}

/**
 * Same as above except doesn't transform the message
 *
 * @param $key String
 * @return String
 */
function wfMsgForContentNoTrans( $key ) {
	global $wgForceUIMsgAsContentMsg;
	$args = func_get_args();
	array_shift( $args );
	$forcontent = true;
	if( is_array( $wgForceUIMsgAsContentMsg ) &&
		in_array( $key, $wgForceUIMsgAsContentMsg ) )
	{
		$forcontent = false;
	}
	return wfMsgReal( $key, $args, true, $forcontent, false );
}

/**
 * Really get a message
 *
 * @param $key String: key to get.
 * @param $args
 * @param $useDB Boolean
 * @param $forContent Mixed: Language code, or false for user lang, true for content lang.
 * @param $transform Boolean: Whether or not to transform the message.
 * @return String: the requested message.
 */
function wfMsgReal( $key, $args, $useDB = true, $forContent = false, $transform = true ) {
	wfProfileIn( __METHOD__ );
	$message = wfMsgGetKey( $key, $useDB, $forContent, $transform );
	$message = wfMsgReplaceArgs( $message, $args );
	wfProfileOut( __METHOD__ );
	return $message;
}

/**
 * Fetch a message string value, but don't replace any keys yet.
 *
 * @param $key String
 * @param $useDB Bool
 * @param $langCode String: Code of the language to get the message for, or
 *                  behaves as a content language switch if it is a boolean.
 * @param $transform Boolean: whether to parse magic words, etc.
 * @return string
 */
function wfMsgGetKey( $key, $useDB = true, $langCode = false, $transform = true ) {
	wfRunHooks( 'NormalizeMessageKey', array( &$key, &$useDB, &$langCode, &$transform ) );

	$cache = MessageCache::singleton();
	$message = $cache->get( $key, $useDB, $langCode );
	if( $message === false ) {
		$message = '&lt;' . htmlspecialchars( $key ) . '&gt;';
	} elseif ( $transform ) {
		$message = $cache->transform( $message );
	}
	return $message;
}

/**
 * Replace message parameter keys on the given formatted output.
 *
 * @param $message String
 * @param $args Array
 * @return string
 * @private
 */
function wfMsgReplaceArgs( $message, $args ) {
	# Fix windows line-endings
	# Some messages are split with explode("\n", $msg)
	$message = str_replace( "\r", '', $message );

	// Replace arguments
	if ( count( $args ) ) {
		if ( is_array( $args[0] ) ) {
			$args = array_values( $args[0] );
		}
		$replacementKeys = array();
		foreach( $args as $n => $param ) {
			$replacementKeys['$' . ( $n + 1 )] = $param;
		}
		$message = strtr( $message, $replacementKeys );
	}

	return $message;
}

/**
 * Return an HTML-escaped version of a message.
 * Parameter replacements, if any, are done *after* the HTML-escaping,
 * so parameters may contain HTML (eg links or form controls). Be sure
 * to pre-escape them if you really do want plaintext, or just wrap
 * the whole thing in htmlspecialchars().
 *
 * @param $key String
 * @param string ... parameters
 * @return string
 */
function wfMsgHtml( $key ) {
	$args = func_get_args();
	array_shift( $args );
	return wfMsgReplaceArgs( htmlspecialchars( wfMsgGetKey( $key ) ), $args );
}

/**
 * Return an HTML version of message
 * Parameter replacements, if any, are done *after* parsing the wiki-text message,
 * so parameters may contain HTML (eg links or form controls). Be sure
 * to pre-escape them if you really do want plaintext, or just wrap
 * the whole thing in htmlspecialchars().
 *
 * @param $key String
 * @param string ... parameters
 * @return string
 */
function wfMsgWikiHtml( $key ) {
	$args = func_get_args();
	array_shift( $args );
	return wfMsgReplaceArgs(
		MessageCache::singleton()->parse( wfMsgGetKey( $key ), null,
		/* can't be set to false */ true, /* interface */ true )->getText(),
		$args );
}

/**
 * Returns message in the requested format
 * @param $key String: key of the message
 * @param $options Array: processing rules. Can take the following options:
 *   <i>parse</i>: parses wikitext to HTML
 *   <i>parseinline</i>: parses wikitext to HTML and removes the surrounding
 *       p's added by parser or tidy
 *   <i>escape</i>: filters message through htmlspecialchars
 *   <i>escapenoentities</i>: same, but allows entity references like &#160; through
 *   <i>replaceafter</i>: parameters are substituted after parsing or escaping
 *   <i>parsemag</i>: transform the message using magic phrases
 *   <i>content</i>: fetch message for content language instead of interface
 * Also can accept a single associative argument, of the form 'language' => 'xx':
 *   <i>language</i>: Language object or language code to fetch message for
 *       (overriden by <i>content</i>).
 * Behavior for conflicting options (e.g., parse+parseinline) is undefined.
 *
 * @return String
 */
function wfMsgExt( $key, $options ) {
	$args = func_get_args();
	array_shift( $args );
	array_shift( $args );
	$options = (array)$options;

	foreach( $options as $arrayKey => $option ) {
		if( !preg_match( '/^[0-9]+|language$/', $arrayKey ) ) {
			# An unknown index, neither numeric nor "language"
			wfWarn( "wfMsgExt called with incorrect parameter key $arrayKey", 1, E_USER_WARNING );
		} elseif( preg_match( '/^[0-9]+$/', $arrayKey ) && !in_array( $option,
		array( 'parse', 'parseinline', 'escape', 'escapenoentities',
		'replaceafter', 'parsemag', 'content' ) ) ) {
			# A numeric index with unknown value
			wfWarn( "wfMsgExt called with incorrect parameter $option", 1, E_USER_WARNING );
		}
	}

	if( in_array( 'content', $options, true ) ) {
		$forContent = true;
		$langCode = true;
		$langCodeObj = null;
	} elseif( array_key_exists( 'language', $options ) ) {
		$forContent = false;
		$langCode = wfGetLangObj( $options['language'] );
		$langCodeObj = $langCode;
	} else {
		$forContent = false;
		$langCode = false;
		$langCodeObj = null;
	}

	$string = wfMsgGetKey( $key, /*DB*/true, $langCode, /*Transform*/false );

	if( !in_array( 'replaceafter', $options, true ) ) {
		$string = wfMsgReplaceArgs( $string, $args );
	}

	$messageCache = MessageCache::singleton();
	$parseInline = in_array( 'parseinline', $options, true );
	if( in_array( 'parse', $options, true ) || $parseInline ) {
		$string = $messageCache->parse( $string, null, true, !$forContent, $langCodeObj );
		if ( $string instanceof ParserOutput ) {
			$string = $string->getText();
		}

		if ( $parseInline ) {
			$m = array();
			if( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $string, $m ) ) {
				$string = $m[1];
			}
		}
	} elseif ( in_array( 'parsemag', $options, true ) ) {
		$string = $messageCache->transform( $string,
				!$forContent, $langCodeObj );
	}

	if ( in_array( 'escape', $options, true ) ) {
		$string = htmlspecialchars ( $string );
	} elseif ( in_array( 'escapenoentities', $options, true ) ) {
		$string = Sanitizer::escapeHtmlAllowEntities( $string );
	}

	if( in_array( 'replaceafter', $options, true ) ) {
		$string = wfMsgReplaceArgs( $string, $args );
	}

	return $string;
}

/**
 * Since wfMsg() and co suck, they don't return false if the message key they
 * looked up didn't exist but a XHTML string, this function checks for the
 * nonexistance of messages by checking the MessageCache::get() result directly.
 *
 * @param $key      String: the message key looked up
 * @return Boolean True if the message *doesn't* exist.
 */
function wfEmptyMsg( $key ) {
	return MessageCache::singleton()->get( $key, /*useDB*/true, /*content*/false ) === false;
}

/**
 * Throw a debugging exception. This function previously once exited the process,
 * but now throws an exception instead, with similar results.
 *
 * @param $msg String: message shown when dying.
 */
function wfDebugDieBacktrace( $msg = '' ) {
	throw new MWException( $msg );
}

/**
 * Fetch server name for use in error reporting etc.
 * Use real server name if available, so we know which machine
 * in a server farm generated the current page.
 *
 * @return string
 */
function wfHostname() {
	static $host;
	if ( is_null( $host ) ) {
		if ( function_exists( 'posix_uname' ) ) {
			// This function not present on Windows
			$uname = posix_uname();
		} else {
			$uname = false;
		}
		if( is_array( $uname ) && isset( $uname['nodename'] ) ) {
			$host = $uname['nodename'];
		} elseif ( getenv( 'COMPUTERNAME' ) ) {
			# Windows computer name
			$host = getenv( 'COMPUTERNAME' );
		} else {
			# This may be a virtual server.
			$host = $_SERVER['SERVER_NAME'];
		}
	}
	return $host;
}

/**
 * Returns a HTML comment with the elapsed time since request.
 * This method has no side effects.
 *
 * @return string
 */
function wfReportTime() {
	global $wgRequestTime, $wgShowHostnames;

	$elapsed = microtime( true ) - $wgRequestTime;

	return $wgShowHostnames
		? sprintf( '<!-- Served by %s in %01.3f secs. -->', wfHostname(), $elapsed )
		: sprintf( '<!-- Served in %01.3f secs. -->', $elapsed );
}

/**
 * Safety wrapper for debug_backtrace().
 *
 * With Zend Optimizer 3.2.0 loaded, this causes segfaults under somewhat
 * murky circumstances, which may be triggered in part by stub objects
 * or other fancy talkin'.
 *
 * Will return an empty array if Zend Optimizer is detected or if
 * debug_backtrace is disabled, otherwise the output from
 * debug_backtrace() (trimmed).
 *
 * @param $limit int This parameter can be used to limit the number of stack frames returned
 *
 * @return array of backtrace information
 */
function wfDebugBacktrace( $limit = 0 ) {
	static $disabled = null;

	if( extension_loaded( 'Zend Optimizer' ) ) {
		wfDebug( "Zend Optimizer detected; skipping debug_backtrace for safety.\n" );
		return array();
	}

	if ( is_null( $disabled ) ) {
		$disabled = false;
		$functions = explode( ',', ini_get( 'disable_functions' ) );
		$functions = array_map( 'trim', $functions );
		$functions = array_map( 'strtolower', $functions );
		if ( in_array( 'debug_backtrace', $functions ) ) {
			wfDebug( "debug_backtrace is in disabled_functions\n" );
			$disabled = true;
		}
	}
	if ( $disabled ) {
		return array();
	}

	if ( $limit && version_compare( PHP_VERSION, '5.4.0', '>=' ) ) {
		return array_slice( debug_backtrace( DEBUG_BACKTRACE_PROVIDE_OBJECT, $limit ), 1 );
	} else {
		return array_slice( debug_backtrace(), 1 );
	}
}

/**
 * Get a debug backtrace as a string
 *
 * @return string
 */
function wfBacktrace() {
	global $wgCommandLineMode;

	if ( $wgCommandLineMode ) {
		$msg = '';
	} else {
		$msg = "<ul>\n";
	}
	$backtrace = wfDebugBacktr…