GlobalFunctions.php

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

// Hide compatibility functions from Doxygen

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

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

        function mb_substr_split_unicode( $str, $splitPos ) {
                return Fallback::mb_substr_split_unicode( $str, $splitPos );
        }
}

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

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

}

if( !function_exists( 'mb_strrpos' ) ) {
        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' ) ) {
        function istainted( $var ) {
                return 0;
        }
        function taint( $var, $level = 0 ) {}
        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 );
}

function wfArrayDiff2( $a, $b ) {
        return array_udiff( $a, $b, 'wfArrayDiff2_cmp' );
}

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;
        }
}

function wfArrayLookup( $a, $b ) {
        return array_flip( array_intersect( array_flip( $a ), array_keys( $b ) ) );
}

function wfAppendToArrayIfNotDefault( $key, $value, $default, &$changed ) {
        if ( is_null( $changed ) ) {
                throw new MWException( 'GlobalFunctions::wfAppendToArrayIfNotDefault got null' );
        }
        if ( $default[$key] !== $value ) {
                $changed[$key] = $value;
        }
}

function wfArrayMerge( $array1/* ... */ ) {
        $args = func_get_args();
        $args = array_reverse( $args, true );
        $out = array();
        foreach ( $args as $arg ) {
                $out += $arg;
        }
        return $out;
}

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 );
}

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;
}

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;
}

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;
}

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;
}

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;
}

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;
}

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;
}

function wfAppendQuery( $url, $query ) {
        if ( is_array( $query ) ) {
                $query = wfArrayToCGI( $query );
        }
        if( $query != '' ) {
                if( false === strpos( $url, '?' ) ) {
                        $url .= '?';
                } else {
                        $url .= '&';
                }
                $url .= $query;
        }
        return $url;
}

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;
}

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;
}

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;
}

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;
}

function wfUrlProtocolsWithoutProtRel() {
        return wfUrlProtocols( false );
}

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;
}

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 );
        }
}

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;
}

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 );
}

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;
}

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  ";
}

function wfDebugMem( $exact = false ) {
        $mem = memory_get_usage();
        if( !$exact ) {
                $mem = floor( $mem / 1024 ) . ' kilobytes';
        } else {
                $mem .= ' bytes';
        }
        wfDebug( "Memory usage: $mem\n" );
}

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 );
        }
}

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 );
        }
}

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 );
                }
        }
}

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" );
        }
}

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();
        }
}

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 );
}

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;
}

function wfReadOnlyReason() {
        global $wgReadOnly;
        wfReadOnly();
        return $wgReadOnly;
}

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;
}

function wfUILang() {
        wfDeprecated( __METHOD__, '1.18' );
        global $wgLang;
        return $wgLang;
}

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 );
}

function wfMessageFallback( /*...*/ ) {
        $args = func_get_args();
        return MWFunction::callArray( 'Message::newFallbackSequence', $args );
}

function wfMsg( $key ) {
        $args = func_get_args();
        array_shift( $args );
        return wfMsgReal( $key, $args );
}

function wfMsgNoTrans( $key ) {
        $args = func_get_args();
        array_shift( $args );
        return wfMsgReal( $key, $args, true, false, false );
}

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 );
}

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 );
}

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;
}

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;
}

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;
}

function wfMsgHtml( $key ) {
        $args = func_get_args();
        array_shift( $args );
        return wfMsgReplaceArgs( htmlspecialchars( wfMsgGetKey( $key ) ), $args );
}

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 );
}

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;
}

function wfEmptyMsg( $key ) {
        return MessageCache::singleton()->get( $key, /*useDB*/true, /*content*/false ) === false;
}

function wfDebugDieBacktrace( $msg = '' ) {
        throw new MWException( $msg );
}

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;
}

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 );
}

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 );
        }
}

function wfBacktrace() {
        global $wgCommandLineMode;

        if ( $wgCommandLineMode ) {
                $msg = '';
        } else {
                $msg = "<ul>\n";
        }
        $backtrace = wfDebugBacktrace();
        foreach( $backtrace as $call ) {
                if( isset( $call['file'] ) ) {
                        $f = explode( DIRECTORY_SEPARATOR, $call['file'] );
                        $file = $f[count( $f ) - 1];
                } else {
                        $file = '-';
                }
                if( isset( $call['line'] ) ) {
                        $line = $call['line'];
                } else {
                        $line = '-';
                }
                if ( $wgCommandLineMode ) {
                        $msg .= "$file line $line calls ";
                } else {
                        $msg .= '<li>' . $file . ' line ' . $line . ' calls ';
                }
                if( !empty( $call['class'] ) ) {
                        $msg .= $call['class'] . $call['type'];
                }
                $msg .= $call['function'] . '()';

                if ( $wgCommandLineMode ) {
                        $msg .= "\n";
                } else {
                        $msg .= "</li>\n";
                }
        }
        if ( $wgCommandLineMode ) {
                $msg .= "\n";
        } else {
                $msg .= "</ul>\n";
        }

        return $msg;
}

function wfGetCaller( $level = 2 ) {
        $backtrace = wfDebugBacktrace( $level );
        if ( isset( $backtrace[$level] ) ) {
                return wfFormatStackFrame( $backtrace[$level] );
        } else {
                $caller = 'unknown';
        }
        return $caller;
}

function wfGetAllCallers( $limit = 3 ) {
        $trace = array_reverse( wfDebugBacktrace() );
        if ( !$limit || $limit > count( $trace ) - 1 ) {
                $limit = count( $trace ) - 1;
        }
        $trace = array_slice( $trace, -$limit - 1, $limit );
        return implode( '/', array_map( 'wfFormatStackFrame', $trace ) );
}

function wfFormatStackFrame( $frame ) {
        return isset( $frame['class'] ) ?
                $frame['class'] . '::' . $frame['function'] :
                $frame['function'];
}


/* Some generic result counters, pulled out of SearchEngine */


function wfShowingResults( $offset, $limit ) {
        global $wgLang;
        return wfMsgExt(
                'showingresults',
                array( 'parseinline' ),
                $wgLang->formatNum( $limit ),
                $wgLang->formatNum( $offset + 1 )
        );
}

function wfViewPrevNext( $offset, $limit, $link, $query = '', $atend = false ) {
        wfDeprecated( __METHOD__, '1.19' );
        
        global $wgLang;

        $query = wfCgiToArray( $query );

        if( is_object( $link ) ) {
                $title = $link;
        } else {
                $title = Title::newFromText( $link );
                if( is_null( $title ) ) {
                        return false;
                }
        }

        return $wgLang->viewPrevNext( $title, $offset, $limit, $query, $atend );
}

function wfSpecialList( $page, $details, $oppositedm = true ) {
        global $wgLang;
        return $wgLang->specialList( $page, $details, $oppositedm );
}

function wfClientAcceptsGzip( $force = false ) {
        static $result = null;
        if ( $result === null || $force ) {
                $result = false;
                if( isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ) {
                        # @todo FIXME: We may want to blacklist some broken browsers
                        $m = array();
                        if( preg_match(
                                '/\bgzip(?:;(q)=([0-9]+(?:\.[0-9]+)))?\b/',
                                $_SERVER['HTTP_ACCEPT_ENCODING'],
                                $m )
                        )
                        {
                                if( isset( $m[2] ) && ( $m[1] == 'q' ) && ( $m[2] == 0 ) ) {
                                        $result = false;
                                        return $result;
                                }
                                wfDebug( "wfClientAcceptsGzip: client accepts gzip.\n" );
                                $result = true;
                        }
                }
        }
        return $result;
}

function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
        global $wgRequest;
        return $wgRequest->getLimitOffset( $deflimit, $optionname );
}

function wfEscapeWikiText( $text ) {
        $text = strtr( "\n$text", array(
                '"' => '&#34;', '&' => '&#38;', "'" => '&#39;', '<' => '&#60;',
                '=' => '&#61;', '>' => '&#62;', '[' => '&#91;', ']' => '&#93;',
                '{' => '&#123;', '|' => '&#124;', '}' => '&#125;',
                "\n#" => "\n&#35;", "\n*" => "\n&#42;",
                "\n:" => "\n&#58;", "\n;" => "\n&#59;",
                '://' => '&#58;//', 'ISBN ' => 'ISBN&#32;', 'RFC ' => 'RFC&#32;',
        ) );
        return substr( $text, 1 );
}

function wfTime() {
        return microtime( true );
}

function wfSetVar( &$dest, $source, $force = false ) {
        $temp = $dest;
        if ( !is_null( $source ) || $force ) {
                $dest = $source;
        }
        return $temp;
}

function wfSetBit( &$dest, $bit, $state = true ) {
        $temp = (bool)( $dest & $bit );
        if ( !is_null( $state ) ) {
                if ( $state ) {
                        $dest |= $bit;
                } else {
                        $dest &= ~$bit;
                }
        }
        return $temp;
}

function wfVarDump( $var ) {
        global $wgOut;
        $s = str_replace( "\n", "<br />\n", var_export( $var, true ) . "\n" );
        if ( headers_sent() || !isset( $wgOut ) || !is_object( $wgOut ) ) {
                print $s;
        } else {
                $wgOut->addHTML( $s );
        }
}

function wfHttpError( $code, $label, $desc ) {
        global $wgOut;
        $wgOut->disable();
        header( "HTTP/1.0 $code $label" );
        header( "Status: $code $label" );
        $wgOut->sendCacheControl();

        header( 'Content-type: text/html; charset=utf-8' );
        print "<!doctype html>" .
                '<html><head><title>' .
                htmlspecialchars( $label ) .
                '</title></head><body><h1>' .
                htmlspecialchars( $label ) .
                '</h1><p>' .
                nl2br( htmlspecialchars( $desc ) ) .
                "</p></body></html>\n";
}

function wfResetOutputBuffers( $resetGzipEncoding = true ) {
        if( $resetGzipEncoding ) {
                // Suppress Content-Encoding and Content-Length
                // headers from 1.10+s wfOutputHandler
                global $wgDisableOutputCompression;
                $wgDisableOutputCompression = true;
        }
        while( $status = ob_get_status() ) {
                if( $status['type'] == 0 /* PHP_OUTPUT_HANDLER_INTERNAL */ ) {
                        // Probably from zlib.output_compression or other
                        // PHP-internal setting which can't be removed.
                        //
                        // Give up, and hope the result doesn't break
                        // output behavior.
                        break;
                }
                if( !ob_end_clean() ) {
                        // Could not remove output buffer handler; abort now
                        // to avoid getting in some kind of infinite loop.
                        break;
                }
                if( $resetGzipEncoding ) {
                        if( $status['name'] == 'ob_gzhandler' ) {
                                // Reset the 'Content-Encoding' field set by this handler
                                // so we can start fresh.
                                if ( function_exists( 'header_remove' ) ) {
                                        // Available since PHP 5.3.0
                                        header_remove( 'Content-Encoding' );
                                } else {
                                        // We need to provide a valid content-coding. See bug 28069
                                        header( 'Content-Encoding: identity' );
                                }
                                break;
                        }
                }
        }
}

function wfClearOutputBuffers() {
        wfResetOutputBuffers( false );
}

function wfAcceptToPrefs( $accept, $def = '*/*' ) {
        # No arg means accept anything (per HTTP spec)
        if( !$accept ) {
                return array( $def => 1.0 );
        }

        $prefs = array();

        $parts = explode( ',', $accept );

        foreach( $parts as $part ) {
                # @todo FIXME: Doesn't deal with params like 'text/html; level=1'
                $values = explode( ';', trim( $part ) );
                $match = array();
                if ( count( $values ) == 1 ) {
                        $prefs[$values[0]] = 1.0;
                } elseif ( preg_match( '/q\s*=\s*(\d*\.\d+)/', $values[1], $match ) ) {
                        $prefs[$values[0]] = floatval( $match[1] );
                }
        }

        return $prefs;
}

function mimeTypeMatch( $type, $avail ) {
        if( array_key_exists( $type, $avail ) ) {
                return $type;
        } else {
                $parts = explode( '/', $type );
                if( array_key_exists( $parts[0] . '/*', $avail ) ) {
                        return $parts[0] . '/*';
                } elseif( array_key_exists( '*/*', $avail ) ) {
                        return '*/*';
                } else {
                        return null;
                }
        }
}

function wfNegotiateType( $cprefs, $sprefs ) {
        $combine = array();

        foreach( array_keys( $sprefs ) as $type ) {
                $parts = explode( '/', $type );
                if( $parts[1] != '*' ) {
                        $ckey = mimeTypeMatch( $type, $cprefs );
                        if( $ckey ) {
                                $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
                        }
                }
        }

        foreach( array_keys( $cprefs ) as $type ) {
                $parts = explode( '/', $type );
                if( $parts[1] != '*' && !array_key_exists( $type, $sprefs ) ) {
                        $skey = mimeTypeMatch( $type, $sprefs );
                        if( $skey ) {
                                $combine[$type] = $sprefs[$skey] * $cprefs[$type];
                        }
                }
        }

        $bestq = 0;
        $besttype = null;

        foreach( array_keys( $combine ) as $type ) {
                if( $combine[$type] > $bestq ) {
                        $besttype = $type;
                        $bestq = $combine[$type];
                }
        }

        return $besttype;
}

function wfSuppressWarnings( $end = false ) {
        static $suppressCount = 0;
        static $originalLevel = false;

        if ( $end ) {
                if ( $suppressCount ) {
                        --$suppressCount;
                        if ( !$suppressCount ) {
                                error_reporting( $originalLevel );
                        }
                }
        } else {
                if ( !$suppressCount ) {
                        // E_DEPRECATED and E_USER_DEPRECATED are undefined in PHP 5.2
                        if( !defined( 'E_DEPRECATED' ) ) {
                                define( 'E_DEPRECATED', 8192 );
                        }
                        if( !defined( 'E_USER_DEPRECATED' ) ) {
                                define( 'E_USER_DEPRECATED', 16384 );
                        }
                        $originalLevel = error_reporting( E_ALL & ~( E_WARNING | E_NOTICE | E_USER_WARNING | E_USER_NOTICE | E_DEPRECATED | E_USER_DEPRECATED | E_STRICT ) );
                }
                ++$suppressCount;
        }
}

function wfRestoreWarnings() {
        wfSuppressWarnings( true );
}

# Autodetect, convert and provide timestamps of various types

define( 'TS_UNIX', 0 );

define( 'TS_MW', 1 );

define( 'TS_DB', 2 );

define( 'TS_RFC2822', 3 );

define( 'TS_ISO_8601', 4 );

define( 'TS_EXIF', 5 );

define( 'TS_ORACLE', 6 );

define( 'TS_POSTGRES', 7 );

define( 'TS_DB2', 8 );

define( 'TS_ISO_8601_BASIC', 9 );

function wfTimestamp( $outputtype = TS_UNIX, $ts = 0 ) {
        $uts = 0;
        $da = array();
        $strtime = '';

        if ( !$ts ) { // We want to catch 0, '', null... but not date strings starting with a letter.
                $uts = time();
                $strtime = "@$uts";
        } elseif ( preg_match( '/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)$/D', $ts, $da ) ) {
                # TS_DB
        } elseif ( preg_match( '/^(\d{4}):(\d\d):(\d\d) (\d\d):(\d\d):(\d\d)$/D', $ts, $da ) ) {
                # TS_EXIF
        } elseif ( preg_match( '/^(\d{4})(\d\d)(\d\d)(\d\d)(\d\d)(\d\d)$/D', $ts, $da ) ) {
                # TS_MW
        } elseif ( preg_match( '/^-?\d{1,13}$/D', $ts ) ) {
                # TS_UNIX
                $uts = $ts;
                $strtime = "@$ts"; // http://php.net/manual/en/datetime.formats.compound.php
        } elseif ( preg_match( '/^\d{2}-\d{2}-\d{4} \d{2}:\d{2}:\d{2}.\d{6}$/', $ts ) ) {
                # TS_ORACLE // session altered to DD-MM-YYYY HH24:MI:SS.FF6
                $strtime = preg_replace( '/(\d\d)\.(\d\d)\.(\d\d)(\.(\d+))?/', "$1:$2:$3",
                                str_replace( '+00:00', 'UTC', $ts ) );
        } elseif ( preg_match( '/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})(?:\.*\d*)?Z$/', $ts, $da ) ) {
                # TS_ISO_8601
        } elseif ( preg_match( '/^(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})(\d{2})(?:\.*\d*)?Z$/', $ts, $da ) ) {
                #TS_ISO_8601_BASIC
        } elseif ( preg_match( '/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)\.*\d*[\+\- ](\d\d)$/', $ts, $da ) ) {
                # TS_POSTGRES
        } elseif ( preg_match( '/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)\.*\d* GMT$/', $ts, $da ) ) {
                # TS_POSTGRES
        } elseif (preg_match( '/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)\.\d\d\d$/', $ts, $da ) ) {
                # TS_DB2
        } elseif ( preg_match( '/^[ \t\r\n]*([A-Z][a-z]{2},[ \t\r\n]*)?' . # Day of week
                                                        '\d\d?[ \t\r\n]*[A-Z][a-z]{2}[ \t\r\n]*\d{2}(?:\d{2})?' .  # dd Mon yyyy
                                                        '[ \t\r\n]*\d\d[ \t\r\n]*:[ \t\r\n]*\d\d[ \t\r\n]*:[ \t\r\n]*\d\d/S', $ts ) ) { # hh:mm:ss
                # TS_RFC2822, accepting a trailing comment. See http://www.squid-cache.org/mail-archive/squid-users/200307/0122.html / r77171
                # The regex is a superset of rfc2822 for readability
                $strtime = strtok( $ts, ';' );
        } elseif ( preg_match( '/^[A-Z][a-z]{5,8}, \d\d-[A-Z][a-z]{2}-\d{2} \d\d:\d\d:\d\d/', $ts ) ) {
                # TS_RFC850
                $strtime = $ts;
        } elseif ( preg_match( '/^[A-Z][a-z]{2} [A-Z][a-z]{2} +\d{1,2} \d\d:\d\d:\d\d \d{4}/', $ts ) ) {
                # asctime
                $strtime = $ts;
        } else {
                # Bogus value...
                wfDebug("wfTimestamp() fed bogus time value: TYPE=$outputtype; VALUE=$ts\n");

                return false;
        }

        static $formats = array(
                TS_UNIX => 'U',
                TS_MW => 'YmdHis',
                TS_DB => 'Y-m-d H:i:s',
                TS_ISO_8601 => 'Y-m-d\TH:i:s\Z',
                TS_ISO_8601_BASIC => 'Ymd\THis\Z',
                TS_EXIF => 'Y:m:d H:i:s', // This shouldn't ever be used, but is included for completeness
                TS_RFC2822 => 'D, d M Y H:i:s',
                TS_ORACLE => 'd-m-Y H:i:s.000000', // Was 'd-M-y h.i.s A' . ' +00:00' before r51500
                TS_POSTGRES => 'Y-m-d H:i:s',
                TS_DB2 => 'Y-m-d H:i:s',
        );

        if ( !isset( $formats[$outputtype] ) ) {
                throw new MWException( 'wfTimestamp() called with illegal output type.' );
        }

        if ( function_exists( "date_create" ) ) {
                if ( count( $da ) ) {
                        $ds = sprintf("%04d-%02d-%02dT%02d:%02d:%02d.00+00:00",
                                (int)$da[1], (int)$da[2], (int)$da[3],
                                (int)$da[4], (int)$da[5], (int)$da[6]);

                        $d = date_create( $ds, new DateTimeZone( 'GMT' ) );
                } elseif ( $strtime ) {
                        $d = date_create( $strtime, new DateTimeZone( 'GMT' ) );
                } else {
                        return false;
                }

                if ( !$d ) {
                        wfDebug("wfTimestamp() fed bogus time value: $outputtype; $ts\n");
                        return false;
                }

                $output = $d->format( $formats[$outputtype] );
        } else {
                if ( count( $da ) ) {
                        // Warning! gmmktime() acts oddly if the month or day is set to 0
                        // We may want to handle that explicitly at some point
                        $uts = gmmktime( (int)$da[4], (int)$da[5], (int)$da[6],
                                (int)$da[2], (int)$da[3], (int)$da[1] );
                } elseif ( $strtime ) {
                        $uts = strtotime( $strtime );
                }

                if ( $uts === false ) {
                        wfDebug("wfTimestamp() can't parse the timestamp (non 32-bit time? Update php): $outputtype; $ts\n");
                        return false;
                }

                if ( TS_UNIX == $outputtype ) {
                        return $uts;
                }
                $output = gmdate( $formats[$outputtype], $uts );
        }

        if ( ( $outputtype == TS_RFC2822 ) || ( $outputtype == TS_POSTGRES ) ) {
                $output .= ' GMT';
        }

        return $output;
}

function wfTimestampOrNull( $outputtype = TS_UNIX, $ts = null ) {
        if( is_null( $ts ) ) {
                return null;
        } else {
                return wfTimestamp( $outputtype, $ts );
        }
}

function wfTimestampNow() {
        # return NOW
        return wfTimestamp( TS_MW, time() );
}

function wfIsWindows() {
        static $isWindows = null;
        if ( $isWindows === null ) {
                $isWindows = substr( php_uname(), 0, 7 ) == 'Windows';
        }
        return $isWindows;
}

function wfIsHipHop() {
        return function_exists( 'hphp_thread_set_warmup_enabled' );
}

function swap( &$x, &$y ) {
        $z = $x;
        $x = $y;
        $y = $z;
}

function wfTempDir() {
        foreach( array( 'TMPDIR', 'TMP', 'TEMP' ) as $var ) {
                $tmp = getenv( $var );
                if( $tmp && file_exists( $tmp ) && is_dir( $tmp ) && is_writable( $tmp ) ) {
                        return $tmp;
                }
        }
        if( function_exists( 'sys_get_temp_dir' ) ) {
                return sys_get_temp_dir();
        }
        # Usual defaults
        return wfIsWindows() ? 'C:\Windows\Temp' : '/tmp';
}

function wfMkdirParents( $dir, $mode = null, $caller = null ) {
        global $wgDirectoryMode;

        if ( FileBackend::isStoragePath( $dir ) ) { // sanity
                throw new MWException( __FUNCTION__ . " given storage path `$dir`.");
        }

        if ( !is_null( $caller ) ) {
                wfDebug( "$caller: called wfMkdirParents($dir)\n" );
        }

        if( strval( $dir ) === '' || file_exists( $dir ) ) {
                return true;
        }

        $dir = str_replace( array( '\\', '/' ), DIRECTORY_SEPARATOR, $dir );

        if ( is_null( $mode ) ) {
                $mode = $wgDirectoryMode;
        }

        // Turn off the normal warning, we're doing our own below
        wfSuppressWarnings();
        $ok = mkdir( $dir, $mode, true ); // PHP5 <3
        wfRestoreWarnings();

        if( !$ok ) {
                // PHP doesn't report the path in its warning message, so add our own to aid in diagnosis.
                trigger_error( __FUNCTION__ . ": failed to mkdir \"$dir\" mode $mode", E_USER_WARNING );
        }
        return $ok;
}

function wfIncrStats( $key, $count = 1 ) {
        global $wgStatsMethod;

        $count = intval( $count );

        if( $wgStatsMethod == 'udp' ) {
                global $wgUDPProfilerHost, $wgUDPProfilerPort, $wgDBname, $wgAggregateStatsID;
                static $socket;

                $id = $wgAggregateStatsID !== false ? $wgAggregateStatsID : $wgDBname;

                if ( !$socket ) {
                        $socket = socket_create( AF_INET, SOCK_DGRAM, SOL_UDP );
                        $statline = "stats/{$id} - {$count} 1 1 1 1 -total\n";
                        socket_sendto(
                                $socket,
                                $statline,
                                strlen( $statline ),
                                0,
                                $wgUDPProfilerHost,
                                $wgUDPProfilerPort
                        );
                }
                $statline = "stats/{$id} - {$count} 1 1 1 1 {$key}\n";
                wfSuppressWarnings();
                socket_sendto(
                        $socket,
                        $statline,
                        strlen( $statline ),
                        0,
                        $wgUDPProfilerHost,
                        $wgUDPProfilerPort
                );
                wfRestoreWarnings();
        } elseif( $wgStatsMethod == 'cache' ) {
                global $wgMemc;
                $key = wfMemcKey( 'stats', $key );
                if ( is_null( $wgMemc->incr( $key, $count ) ) ) {
                        $wgMemc->add( $key, $count );
                }
        } else {
                // Disabled
        }
}

function wfRecursiveRemoveDir( $dir ) {
        wfDebug( __FUNCTION__ . "( $dir )\n" );
        // taken from http://de3.php.net/manual/en/function.rmdir.php#98622
        if ( is_dir( $dir ) ) {
                $objects = scandir( $dir );
                foreach ( $objects as $object ) {
                        if ( $object != "." && $object != ".." ) {
                                if ( filetype( $dir . '/' . $object ) == "dir" ) {
                                        wfRecursiveRemoveDir( $dir . '/' . $object );
                                } else {
                                        unlink( $dir . '/' . $object );
                                }
                        }
                }
                reset( $objects );
                rmdir( $dir );
        }
}

function wfPercent( $nr, $acc = 2, $round = true ) {
        $ret = sprintf( "%.${acc}f", $nr );
        return $round ? round( $ret, $acc ) . '%' : "$ret%";
}

function in_string( $needle, $str, $insensitive = false ) {
        $func = 'strpos';
        if( $insensitive ) $func = 'stripos';

        return $func( $str, $needle ) !== false;
}

function wfIniGetBool( $setting ) {
        $val = ini_get( $setting );
        // 'on' and 'true' can't have whitespace around them, but '1' can.
        return strtolower( $val ) == 'on'
                || strtolower( $val ) == 'true'
                || strtolower( $val ) == 'yes'
                || preg_match( "/^\s*[+-]?0*[1-9]/", $val ); // approx C atoi() function
}

function wfDl( $extension, $fileName = null ) {
        if( extension_loaded( $extension ) ) {
                return true;
        }

        $canDl = false;
        $sapi = php_sapi_name();
        if( version_compare( PHP_VERSION, '5.3.0', '<' ) ||
                $sapi == 'cli' || $sapi == 'cgi' || $sapi == 'embed' )
        {
                $canDl = ( function_exists( 'dl' ) && is_callable( 'dl' )
                && wfIniGetBool( 'enable_dl' ) && !wfIniGetBool( 'safe_mode' ) );
        }

        if( $canDl ) {
                $fileName = $fileName ? $fileName : $extension;
                if( wfIsWindows() ) {
                        $fileName = 'php_' . $fileName;
                }
                wfSuppressWarnings();
                dl( $fileName . '.' . PHP_SHLIB_SUFFIX );
                wfRestoreWarnings();
        }
        return extension_loaded( $extension );
}

function wfEscapeShellArg( ) {
        wfInitShellLocale();

        $args = func_get_args();
        $first = true;
        $retVal = '';
        foreach ( $args as $arg ) {
                if ( !$first ) {
                        $retVal .= ' ';
                } else {
                        $first = false;
                }

                if ( wfIsWindows() ) {
                        // Escaping for an MSVC-style command line parser and CMD.EXE
                        // Refs:
                        //  * http://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
                        //  * http://technet.microsoft.com/en-us/library/cc723564.aspx
                        //  * Bug #13518
                        //  * CR r63214
                        // Double the backslashes before any double quotes. Escape the double quotes.
                        $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
                        $arg = '';
                        $iteration = 0;
                        foreach ( $tokens as $token ) {
                                if ( $iteration % 2 == 1 ) {
                                        // Delimiter, a double quote preceded by zero or more slashes
                                        $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
                                } elseif ( $iteration % 4 == 2 ) {
                                        // ^ in $token will be outside quotes, need to be escaped
                                        $arg .= str_replace( '^', '^^', $token );
                                } else { // $iteration % 4 == 0
                                        // ^ in $token will appear inside double quotes, so leave as is
                                        $arg .= $token;
                                }
                                $iteration++;
                        }
                        // Double the backslashes before the end of the string, because
                        // we will soon add a quote
                        $m = array();
                        if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
                                $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
                        }

                        // Add surrounding quotes
                        $retVal .= '"' . $arg . '"';
                } else {
                        $retVal .= escapeshellarg( $arg );
                }
        }
        return $retVal;
}

function wfShellExec( $cmd, &$retval = null, $environ = array() ) {
        global $IP, $wgMaxShellMemory, $wgMaxShellFileSize, $wgMaxShellTime;

        static $disabled;
        if ( is_null( $disabled ) ) {
                $disabled = false;
                if( wfIniGetBool( 'safe_mode' ) ) {
                        wfDebug( "wfShellExec can't run in safe_mode, PHP's exec functions are too broken.\n" );
                        $disabled = 'safemode';
                } else {
                        $functions = explode( ',', ini_get( 'disable_functions' ) );
                        $functions = array_map( 'trim', $functions );
                        $functions = array_map( 'strtolower', $functions );
                        if ( in_array( 'passthru', $functions ) ) {
                                wfDebug( "passthru is in disabled_functions\n" );
                                $disabled = 'passthru';
                        }
                }
        }
        if ( $disabled ) {
                $retval = 1;
                return $disabled == 'safemode' ?
                        'Unable to run external programs in safe mode.' :
                        'Unable to run external programs, passthru() is disabled.';
        }

        wfInitShellLocale();

        $envcmd = '';
        foreach( $environ as $k => $v ) {
                if ( wfIsWindows() ) {
                        /* Surrounding a set in quotes (method used by wfEscapeShellArg) makes the quotes themselves
                         * appear in the environment variable, so we must use carat escaping as documented in
                         * http://technet.microsoft.com/en-us/library/cc723564.aspx
                         * Note however that the quote isn't listed there, but is needed, and the parentheses
                         * are listed there but doesn't appear to need it.
                         */
                        $envcmd .= "set $k=" . preg_replace( '/([&|()<>^"])/', '^\\1', $v ) . '&& ';
                } else {
                        /* Assume this is a POSIX shell, thus required to accept variable assignments before the command
                         * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_01
                         */
                        $envcmd .= "$k=" . escapeshellarg( $v ) . ' ';
                }
        }
        $cmd = $envcmd . $cmd;

        if ( wfIsWindows() ) {
                if ( version_compare( PHP_VERSION, '5.3.0', '<' ) && /* Fixed in 5.3.0 :) */
                        ( version_compare( PHP_VERSION, '5.2.1', '>=' ) || php_uname( 's' ) == 'Windows NT' ) )
                {
                        # Hack to work around PHP's flawed invocation of cmd.exe
                        # http://news.php.net/php.internals/21796
                        # Windows 9x doesn't accept any kind of quotes
                        $cmd = '"' . $cmd . '"';
                }
        } elseif ( php_uname( 's' ) == 'Linux' ) {
                $time = intval( $wgMaxShellTime );
                $mem = intval( $wgMaxShellMemory );
                $filesize = intval( $wgMaxShellFileSize );

                if ( $time > 0 && $mem > 0 ) {
                        $script = "$IP/bin/ulimit4.sh";
                        if ( is_executable( $script ) ) {
                                $cmd = '/bin/bash ' . escapeshellarg( $script ) . " $time $mem $filesize " . escapeshellarg( $cmd );
                        }
                }
        }
        wfDebug( "wfShellExec: $cmd\n" );

        $retval = 1; // error by default?
        ob_start();
        passthru( $cmd, $retval );
        $output = ob_get_contents();
        ob_end_clean();

        if ( $retval == 127 ) {
                wfDebugLog( 'exec', "Possibly missing executable file: $cmd\n" );
        }
        return $output;
}

function wfInitShellLocale() {
        static $done = false;
        if ( $done ) {
                return;
        }
        $done = true;
        global $wgShellLocale;
        if ( !wfIniGetBool( 'safe_mode' ) ) {
                putenv( "LC_CTYPE=$wgShellLocale" );
                setlocale( LC_CTYPE, $wgShellLocale );
        }
}

function wfShellMaintenanceCmd( $script, array $parameters = array(), array $options = array() ) {
        global $wgPhpCli;
        // Give site config file a chance to run the script in a wrapper.
        // The caller may likely want to call wfBasename() on $script.
        wfRunHooks( 'wfShellMaintenanceCmd', array( &$script, &$parameters, &$options ) );
        $cmd = isset( $options['php'] ) ? array( $options['php'] ) : array( $wgPhpCli );
        if ( isset( $options['wrapper'] ) ) {
                $cmd[] = $options['wrapper'];
        }
        $cmd[] = $script;
        // Escape each parameter for shell
        return implode( " ", array_map( 'wfEscapeShellArg', array_merge( $cmd, $parameters ) ) );
}

function wfMerge( $old, $mine, $yours, &$result ) {
        global $wgDiff3;

        # This check may also protect against code injection in
        # case of broken installations.
        wfSuppressWarnings();
        $haveDiff3 = $wgDiff3 && file_exists( $wgDiff3 );
        wfRestoreWarnings();

        if( !$haveDiff3 ) {
                wfDebug( "diff3 not found\n" );
                return false;
        }

        # Make temporary files
        $td = wfTempDir();
        $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
        $mytextFile = fopen( $mytextName = tempnam( $td, 'merge-mine-' ), 'w' );
        $yourtextFile = fopen( $yourtextName = tempnam( $td, 'merge-your-' ), 'w' );

        fwrite( $oldtextFile, $old );
        fclose( $oldtextFile );
        fwrite( $mytextFile, $mine );
        fclose( $mytextFile );
        fwrite( $yourtextFile, $yours );
        fclose( $yourtextFile );

        # Check for a conflict
        $cmd = $wgDiff3 . ' -a --overlap-only ' .
                wfEscapeShellArg( $mytextName ) . ' ' .
                wfEscapeShellArg( $oldtextName ) . ' ' .
                wfEscapeShellArg( $yourtextName );
        $handle = popen( $cmd, 'r' );

        if( fgets( $handle, 1024 ) ) {
                $conflict = true;
        } else {
                $conflict = false;
        }
        pclose( $handle );

        # Merge differences
        $cmd = $wgDiff3 . ' -a -e --merge ' .
                wfEscapeShellArg( $mytextName, $oldtextName, $yourtextName );
        $handle = popen( $cmd, 'r' );
        $result = '';
        do {
                $data = fread( $handle, 8192 );
                if ( strlen( $data ) == 0 ) {
                        break;
                }
                $result .= $data;
        } while ( true );
        pclose( $handle );
        unlink( $mytextName );
        unlink( $oldtextName );
        unlink( $yourtextName );

        if ( $result === '' && $old !== '' && !$conflict ) {
                wfDebug( "Unexpected null result from diff3. Command: $cmd\n" );
                $conflict = true;
        }
        return !$conflict;
}

function wfDiff( $before, $after, $params = '-u' ) {
        if ( $before == $after ) {
                return '';
        }

        global $wgDiff;
        wfSuppressWarnings();
        $haveDiff = $wgDiff && file_exists( $wgDiff );
        wfRestoreWarnings();

        # This check may also protect against code injection in
        # case of broken installations.
        if( !$haveDiff ) {
                wfDebug( "diff executable not found\n" );
                $diffs = new Diff( explode( "\n", $before ), explode( "\n", $after ) );
                $format = new UnifiedDiffFormatter();
                return $format->format( $diffs );
        }

        # Make temporary files
        $td = wfTempDir();
        $oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
        $newtextFile = fopen( $newtextName = tempnam( $td, 'merge-your-' ), 'w' );

        fwrite( $oldtextFile, $before );
        fclose( $oldtextFile );
        fwrite( $newtextFile, $after );
        fclose( $newtextFile );

        // Get the diff of the two files
        $cmd = "$wgDiff " . $params . ' ' . wfEscapeShellArg( $oldtextName, $newtextName );

        $h = popen( $cmd, 'r' );

        $diff = '';

        do {
                $data = fread( $h, 8192 );
                if ( strlen( $data ) == 0 ) {
                        break;
                }
                $diff .= $data;
        } while ( true );

        // Clean up
        pclose( $h );
        unlink( $oldtextName );
        unlink( $newtextName );

        // Kill the --- and +++ lines. They're not useful.
        $diff_lines = explode( "\n", $diff );
        if ( strpos( $diff_lines[0], '---' ) === 0 ) {
                unset( $diff_lines[0] );
        }
        if ( strpos( $diff_lines[1], '+++' ) === 0 ) {
                unset( $diff_lines[1] );
        }

        $diff = implode( "\n", $diff_lines );

        return $diff;
}

function wfUsePHP( $req_ver ) {
        $php_ver = PHP_VERSION;

        if ( version_compare( $php_ver, (string)$req_ver, '<' ) ) {
                throw new MWException( "PHP $req_ver required--this is only $php_ver" );
        }
}

function wfUseMW( $req_ver ) {
        global $wgVersion;

        if ( version_compare( $wgVersion, (string)$req_ver, '<' ) ) {
                throw new MWException( "MediaWiki $req_ver required--this is only $wgVersion" );
        }
}

function wfBaseName( $path, $suffix = '' ) {
        $encSuffix = ( $suffix == '' )
                ? ''
                : ( '(?:' . preg_quote( $suffix, '#' ) . ')?' );
        $matches = array();
        if( preg_match( "#([^/\\\\]*?){$encSuffix}[/\\\\]*$#", $path, $matches ) ) {
                return $matches[1];
        } else {
                return '';
        }
}

function wfRelativePath( $path, $from ) {
        // Normalize mixed input on Windows...
        $path = str_replace( '/', DIRECTORY_SEPARATOR, $path );
        $from = str_replace( '/', DIRECTORY_SEPARATOR, $from );

        // Trim trailing slashes -- fix for drive root
        $path = rtrim( $path, DIRECTORY_SEPARATOR );
        $from = rtrim( $from, DIRECTORY_SEPARATOR );

        $pieces = explode( DIRECTORY_SEPARATOR, dirname( $path ) );
        $against = explode( DIRECTORY_SEPARATOR, $from );

        if( $pieces[0] !== $against[0] ) {
                // Non-matching Windows drive letters?
                // Return a full path.
                return $path;
        }

        // Trim off common prefix
        while( count( $pieces ) && count( $against )
                && $pieces[0] == $against[0] ) {
                array_shift( $pieces );
                array_shift( $against );
        }

        // relative dots to bump us to the parent
        while( count( $against ) ) {
                array_unshift( $pieces, '..' );
                array_shift( $against );
        }

        array_push( $pieces, wfBaseName( $path ) );

        return implode( DIRECTORY_SEPARATOR, $pieces );
}

function wfDoUpdates( $commit = '' ) {
        wfDeprecated( __METHOD__, '1.19' );
        DeferredUpdates::doUpdates( $commit );
}

function wfBaseConvert( $input, $sourceBase, $destBase, $pad = 1, $lowercase = true ) {
        $input = strval( $input );
        if( $sourceBase < 2 ||
                $sourceBase > 36 ||
                $destBase < 2 ||
                $destBase > 36 ||
                $pad < 1 ||
                $sourceBase != intval( $sourceBase ) ||
                $destBase != intval( $destBase ) ||
                $pad != intval( $pad ) ||
                !is_string( $input ) ||
                $input == '' ) {
                return false;
        }
        $digitChars = ( $lowercase ) ? '0123456789abcdefghijklmnopqrstuvwxyz' : '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $inDigits = array();
        $outChars = '';

        // Decode and validate input string
        $input = strtolower( $input );
        for( $i = 0; $i < strlen( $input ); $i++ ) {
                $n = strpos( $digitChars, $input[$i] );
                if( $n === false || $n > $sourceBase ) {
                        return false;
                }
                $inDigits[] = $n;
        }

        // Iterate over the input, modulo-ing out an output digit
        // at a time until input is gone.
        while( count( $inDigits ) ) {
                $work = 0;
                $workDigits = array();

                // Long division...
                foreach( $inDigits as $digit ) {
                        $work *= $sourceBase;
                        $work += $digit;

                        if( $work < $destBase ) {
                                // Gonna need to pull another digit.
                                if( count( $workDigits ) ) {
                                        // Avoid zero-padding; this lets us find
                                        // the end of the input very easily when
                                        // length drops to zero.
                                        $workDigits[] = 0;
                                }
                        } else {
                                // Finally! Actual division!
                                $workDigits[] = intval( $work / $destBase );

                                // Isn't it annoying that most programming languages
                                // don't have a single divide-and-remainder operator,
                                // even though the CPU implements it that way?
                                $work = $work % $destBase;
                        }
                }

                // All that division leaves us with a remainder,
                // which is conveniently our next output digit.
                $outChars .= $digitChars[$work];

                // And we continue!
                $inDigits = $workDigits;
        }

        while( strlen( $outChars ) < $pad ) {
                $outChars .= '0';
        }

        return strrev( $outChars );
}

function wfCreateObject( $name, $p ) {
        wfDeprecated( __FUNCTION__, '1.18' );
        return MWFunction::newObj( $name, $p );
}

function wfHttpOnlySafe() {
        global $wgHttpOnlyBlacklist;

        if( isset( $_SERVER['HTTP_USER_AGENT'] ) ) {
                foreach( $wgHttpOnlyBlacklist as $regex ) {
                        if( preg_match( $regex, $_SERVER['HTTP_USER_AGENT'] ) ) {
                                return false;
                        }
                }
        }

        return true;
}

function wfCheckEntropy() {
        return (
                        ( wfIsWindows() && version_compare( PHP_VERSION, '5.3.3', '>=' ) )
                        || ini_get( 'session.entropy_file' )
                )
                && intval( ini_get( 'session.entropy_length' ) ) >= 32;
}

function wfFixSessionID() {
        // If the cookie or session id is already set we already have a session and should abort
        if ( isset( $_COOKIE[ session_name() ] ) || session_id() ) {
                return;
        }

        $entropyEnabled = wfCheckEntropy();

        // If built-in entropy is not enabled or not sufficient override php's built in session id generation code
        if ( !$entropyEnabled ) {
                wfDebug( __METHOD__ . ": PHP's built in entropy is disabled or not sufficient, overriding session id generation using our cryptrand source.\n" );
                session_id( MWCryptRand::generateHex( 32 ) );
        }
}

function wfSetupSession( $sessionId = false ) {
        global $wgSessionsInMemcached, $wgCookiePath, $wgCookieDomain,
                        $wgCookieSecure, $wgCookieHttpOnly, $wgSessionHandler;
        if( $wgSessionsInMemcached ) {
                if ( !defined( 'MW_COMPILED' ) ) {
                        global $IP;
                        require_once( "$IP/includes/cache/MemcachedSessions.php" );
                }
                session_set_save_handler( 'memsess_open', 'memsess_close', 'memsess_read',
                        'memsess_write', 'memsess_destroy', 'memsess_gc' );

                // It's necessary to register a shutdown function to call session_write_close(),
                // because by the time the request shutdown function for the session module is
                // called, $wgMemc has already been destroyed. Shutdown functions registered
                // this way are called before object destruction.
                register_shutdown_function( 'memsess_write_close' );
        } elseif( $wgSessionHandler && $wgSessionHandler != ini_get( 'session.save_handler' ) ) {
                # Only set this if $wgSessionHandler isn't null and session.save_handler
                # hasn't already been set to the desired value (that causes errors)
                ini_set( 'session.save_handler', $wgSessionHandler );
        }
        $httpOnlySafe = wfHttpOnlySafe() && $wgCookieHttpOnly;
        wfDebugLog( 'cookie',
                'session_set_cookie_params: "' . implode( '", "',
                        array(
                                0,
                                $wgCookiePath,
                                $wgCookieDomain,
                                $wgCookieSecure,
                                $httpOnlySafe ) ) . '"' );
        session_set_cookie_params( 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $httpOnlySafe );
        session_cache_limiter( 'private, must-revalidate' );
        if ( $sessionId ) {
                session_id( $sessionId );
        } else {
                wfFixSessionID();
        }
        wfSuppressWarnings();
        session_start();
        wfRestoreWarnings();
}

function wfGetPrecompiledData( $name ) {
        global $IP;

        $file = "$IP/serialized/$name";
        if ( file_exists( $file ) ) {
                $blob = file_get_contents( $file );
                if ( $blob ) {
                        return unserialize( $blob );
                }
        }
        return false;
}

function wfMemcKey( /*... */ ) {
        global $wgCachePrefix;
        $prefix = $wgCachePrefix === false ? wfWikiID() : $wgCachePrefix;
        $args = func_get_args();
        $key = $prefix . ':' . implode( ':', $args );
        $key = str_replace( ' ', '_', $key );
        return $key;
}

function wfForeignMemcKey( $db, $prefix /*, ... */ ) {
        $args = array_slice( func_get_args(), 2 );
        if ( $prefix ) {
                $key = "$db-$prefix:" . implode( ':', $args );
        } else {
                $key = $db . ':' . implode( ':', $args );
        }
        return $key;
}

function wfWikiID() {
        global $wgDBprefix, $wgDBname;
        if ( $wgDBprefix ) {
                return "$wgDBname-$wgDBprefix";
        } else {
                return $wgDBname;
        }
}

function wfSplitWikiID( $wiki ) {
        $bits = explode( '-', $wiki, 2 );
        if ( count( $bits ) < 2 ) {
                $bits[] = '';
        }
        return $bits;
}

function &wfGetDB( $db, $groups = array(), $wiki = false ) {
        return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
}

function wfGetLB( $wiki = false ) {
        return wfGetLBFactory()->getMainLB( $wiki );
}

function &wfGetLBFactory() {
        return LBFactory::singleton();
}

function wfFindFile( $title, $options = array() ) {
        return RepoGroup::singleton()->findFile( $title, $options );
}

function wfLocalFile( $title ) {
        return RepoGroup::singleton()->getLocalRepo()->newFile( $title );
}

function wfStreamFile( $fname, $headers = array() ) {
        wfDeprecated( __FUNCTION__, '1.19' );
        StreamFile::stream( $fname, $headers );
}

function wfQueriesMustScale() {
        global $wgMiserMode;
        return $wgMiserMode
                || ( SiteStats::pages() > 100000
                && SiteStats::edits() > 1000000
                && SiteStats::users() > 10000 );
}

function wfScript( $script = 'index' ) {
        global $wgScriptPath, $wgScriptExtension;
        return "{$wgScriptPath}/{$script}{$wgScriptExtension}";
}

function wfGetScriptUrl() {
        if( isset( $_SERVER['SCRIPT_NAME'] ) ) {
                #
                # as it was called, minus the query string.
                #
                # Some sites use Apache rewrite rules to handle subdomains,
                # and have PHP set up in a weird way that causes PHP_SELF
                # to contain the rewritten URL instead of the one that the
                # outside world sees.
                #
                # If in this mode, use SCRIPT_URL instead, which mod_rewrite
                # provides containing the "before" URL.
                return $_SERVER['SCRIPT_NAME'];
        } else {
                return $_SERVER['URL'];
        }
}

function wfBoolToStr( $value ) {
        return $value ? 'true' : 'false';
}

function wfLoadExtensionMessages() {
        wfDeprecated( __FUNCTION__, '1.16' );
}

function wfGetNull() {
        return wfIsWindows()
                ? 'NUL'
                : '/dev/null';
}

function wfWaitForSlaves( $maxLag = false, $wiki = false ) {
        $lb = wfGetLB( $wiki );
        // bug 27975 - Don't try to wait for slaves if there are none
        // Prevents permission error when getting master position
        if ( $lb->getServerCount() > 1 ) {
                $dbw = $lb->getConnection( DB_MASTER );
                $pos = $dbw->getMasterPos();
                $lb->waitForAll( $pos );
        }
}

function wfOut( $s ) {
        wfDeprecated( __FUNCTION__, '1.18' );
        global $wgCommandLineMode;
        if ( $wgCommandLineMode ) {
                echo $s;
        } else {
                echo htmlspecialchars( $s );
        }
        flush();
}

function wfCountDown( $n ) {
        for ( $i = $n; $i >= 0; $i-- ) {
                if ( $i != $n ) {
                        echo str_repeat( "\x08", strlen( $i + 1 ) );
                }
                echo $i;
                flush();
                if ( $i ) {
                        sleep( 1 );
                }
        }
        echo "\n";
}

function wfGenerateToken( $salt = '' ) {
        $salt = serialize( $salt );
        return md5( mt_rand( 0, 0x7fffffff ) . $salt );
}

function wfStripIllegalFilenameChars( $name ) {
        global $wgIllegalFileChars;
        $name = wfBaseName( $name );
        $name = preg_replace(
                "/[^" . Title::legalChars() . "]" .
                        ( $wgIllegalFileChars ? "|[" . $wgIllegalFileChars . "]" : '' ) .
                        "/",
                '-',
                $name
        );
        return $name;
}

function wfMemoryLimit() {
        global $wgMemoryLimit;
        $memlimit = wfShorthandToInteger( ini_get( 'memory_limit' ) );
        if( $memlimit != -1 ) {
                $conflimit = wfShorthandToInteger( $wgMemoryLimit );
                if( $conflimit == -1 ) {
                        wfDebug( "Removing PHP's memory limit\n" );
                        wfSuppressWarnings();
                        ini_set( 'memory_limit', $conflimit );
                        wfRestoreWarnings();
                        return $conflimit;
                } elseif ( $conflimit > $memlimit ) {
                        wfDebug( "Raising PHP's memory limit to $conflimit bytes\n" );
                        wfSuppressWarnings();
                        ini_set( 'memory_limit', $conflimit );
                        wfRestoreWarnings();
                        return $conflimit;
                }
        }
        return $memlimit;
}

function wfShorthandToInteger( $string = '' ) {
        $string = trim( $string );
        if( $string === '' ) {
                return -1;
        }
        $last = $string[strlen( $string ) - 1];
        $val = intval( $string );
        switch( $last ) {
                case 'g':
                case 'G':
                        $val *= 1024;
                        // break intentionally missing
                case 'm':
                case 'M':
                        $val *= 1024;
                        // break intentionally missing
                case 'k':
                case 'K':
                        $val *= 1024;
        }

        return $val;
}

function wfBCP47( $code ) {
        $codeSegment = explode( '-', $code );
        $codeBCP = array();
        foreach ( $codeSegment as $segNo => $seg ) {
                if ( count( $codeSegment ) > 0 ) {
                        // when previous segment is x, it is a private segment and should be lc
                        if( $segNo > 0 && strtolower( $codeSegment[( $segNo - 1 )] ) == 'x' ) {
                                $codeBCP[$segNo] = strtolower( $seg );
                        // ISO 3166 country code
                        } elseif ( ( strlen( $seg ) == 2 ) && ( $segNo > 0 ) ) {
                                $codeBCP[$segNo] = strtoupper( $seg );
                        // ISO 15924 script code
                        } elseif ( ( strlen( $seg ) == 4 ) && ( $segNo > 0 ) ) {
                                $codeBCP[$segNo] = ucfirst( strtolower( $seg ) );
                        // Use lowercase for other cases
                        } else {
                                $codeBCP[$segNo] = strtolower( $seg );
                        }
                } else {
                // Use lowercase for single segment
                        $codeBCP[$segNo] = strtolower( $seg );
                }
        }
        $langCode = implode( '-', $codeBCP );
        return $langCode;
}

function wfGetCache( $inputType ) {
        return ObjectCache::getInstance( $inputType );
}

function wfGetMainCache() {
        global $wgMainCacheType;
        return ObjectCache::getInstance( $wgMainCacheType );
}

function wfGetMessageCacheStorage() {
        global $wgMessageCacheType;
        return ObjectCache::getInstance( $wgMessageCacheType );
}

function wfGetParserCacheStorage() {
        global $wgParserCacheType;
        return ObjectCache::getInstance( $wgParserCacheType );
}

function wfRunHooks( $event, $args = array() ) {
        return Hooks::run( $event, $args );
}

function wfUnpack( $format, $data, $length=false ) {
        if ( $length !== false ) {
                $realLen = strlen( $data );
                if ( $realLen < $length ) {
                        throw new MWException( "Tried to use wfUnpack on a "
                                . "string of length $realLen, but needed one "
                                . "of at least length $length."
                        );
                }
        }

        wfSuppressWarnings();
        $result = unpack( $format, $data );
        wfRestoreWarnings();

        if ( $result === false ) {
                // If it cannot extract the packed data.
                throw new MWException( "unpack could not unpack binary data" );
        }
        return $result;
}