Check if the path is writable before trying to mkdir().

[lhc/web/wiklou.git] / includes / GlobalFunctions.php

<?php

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

/**
 * Global functions used everywhere
 */

require_once dirname(__FILE__) . '/normal/UtfNormalUtil.php';
require_once dirname(__FILE__) . '/XmlFunctions.php';

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

/**
 * Compatibility functions
 *
 * We more or less support PHP 5.0.x and up.
 * Re-implementations of newer functions or functions in non-standard
 * PHP extensions may be included here.
 */
if( !function_exists('iconv') ) {
        # iconv support is not in the default configuration and so may not be present.
        # Assume will only ever use utf-8 and iso-8859-1.
        # This will *not* work in all circumstances.
        function iconv( $from, $to, $string ) {
                if(strcasecmp( $from, $to ) == 0) return $string;
                if(strcasecmp( $from, 'utf-8' ) == 0) return utf8_decode( $string );
                if(strcasecmp( $to, 'utf-8' ) == 0) return utf8_encode( $string );
                return $string;
        }
}

# UTF-8 substr function based on a PHP manual comment
if ( !function_exists( 'mb_substr' ) ) {
        function mb_substr( $str, $start ) {
                $ar = array();
                preg_match_all( '/./us', $str, $ar );

                if( func_num_args() >= 3 ) {
                        $end = func_get_arg( 2 );
                        return join( '', array_slice( $ar[0], $start, $end ) );
                } else {
                        return join( '', array_slice( $ar[0], $start ) );
                }
        }
}

if ( !function_exists( 'mb_strlen' ) ) {
        /**
         * Fallback implementation of mb_strlen, hardcoded to UTF-8.
         * @param string $str
         * @param string $enc optional encoding; ignored
         * @return int
         */
        function mb_strlen( $str, $enc="" ) {
                $counts = count_chars( $str );
                $total = 0;

                // Count ASCII bytes
                for( $i = 0; $i < 0x80; $i++ ) {
                        $total += $counts[$i];
                }

                // Count multibyte sequence heads
                for( $i = 0xc0; $i < 0xff; $i++ ) {
                        $total += $counts[$i];
                }
                return $total;
        }
}

if ( !function_exists( 'array_diff_key' ) ) {
        /**
         * Exists in PHP 5.1.0+
         * Not quite compatible, two-argument version only
         * Null values will cause problems due to this use of isset()
         */
        function array_diff_key( $left, $right ) {
                $result = $left;
                foreach ( $left as $key => $unused ) {
                        if ( isset( $right[$key] ) ) {
                                unset( $result[$key] );
                        }
                }
                return $result;
        }
}

// 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 );
}
/// @endcond


/**
 * Like array_diff( $a, $b ) except that it works with two-dimensional arrays.
 */
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( $keyA, $valueA ) = each( $a ) ) && ( list( $keyB, $valueB ) = each( $b ) ) ) {
                        $cmp = strcmp( $valueA, $valueB );
                        if ( $cmp !== 0 ) {
                                return $cmp;
                        }
                }
                return 0;
        }
}

/**
 * Wrapper for clone(), for compatibility with PHP4-friendly extensions.
 * PHP 5 won't let you declare a 'clone' function, even conditionally,
 * so it has to be a wrapper with a different name.
 */
function wfClone( $object ) {
        return clone( $object );
}

/**
 * Seed Mersenne Twister
 * No-op for compatibility; only necessary in PHP < 4.2.0
 */
function wfSeedRandom() {
        /* No-op */
}

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

/**
 * We want some things to be included as literal characters in our title URLs
 * for prettiness, which urlencode encodes by default.  According to RFC 1738,
 * all of the following should be safe:
 *
 * ;:@&=$-_.+!*'(),
 *
 * But + is not safe because it's used to indicate a space; &= are only safe in
 * paths and not in queries (and we don't distinguish here); ' seems kind of
 * scary; and urlencode() doesn't touch -_. to begin with.  Plus, although /
 * is reserved, we don't care.  So the list we unescape is:
 *
 * ;:@$!*(),/
 *
 * %2F in the page titles seems to fatally break for some reason.
 *
 * @param $s String:
 * @return string
*/
function wfUrlencode( $s ) {
        $s = urlencode( $s );
        $s = str_ireplace(
                array( '%3B','%3A','%40','%24','%21','%2A','%28','%29','%2C','%2F' ),
                array(   ';',  ':',  '@',  '$',  '!',  '*',  '(',  ')',  ',',  '/' ),
                $s
        );

        return $s;
}

/**
 * Sends a line to the debug log if enabled or, optionally, to a comment in output.
 * In normal operation this is a NOP.
 *
 * Controlling globals:
 * $wgDebugLogFile - points to the log file
 * $wgProfileOnly - if set, normal debug messages will not be recorded.
 * $wgDebugRawPage - if false, 'action=raw' hits will not result in debug output.
 * $wgDebugComments - if on, some debug items may appear in comments in the HTML output.
 *
 * @param $text String
 * @param $logonly Bool: set true to avoid appearing in HTML when $wgDebugComments is set
 */
function wfDebug( $text, $logonly = false ) {
        global $wgOut, $wgDebugLogFile, $wgDebugComments, $wgProfileOnly, $wgDebugRawPage;
        global $wgDebugLogPrefix;
        static $recursion = 0;

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

        # Check for raw action using $_GET not $wgRequest, since the latter might not be initialised yet
        if ( isset( $_GET['action'] ) && $_GET['action'] == 'raw' && !$wgDebugRawPage ) {
                return;
        }

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

                if ( !isset( $wgOut ) ) {
                        return;
                }
                if ( !StubObject::isRealObject( $wgOut ) ) {
                        if ( $recursion ) {
                                return;
                        }
                        $recursion++;
                        $wgOut->_unstub();
                        $recursion--;
                }

                // add the message and possible cached ones to the output
                array_map( array( $wgOut, 'debug' ), $cache );
                $cache = array();
        }
        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 );
        }
}

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

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

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

/**
 * Log to a file without getting "file size exceeded" signals.
 * 
 * Can also log to TCP or UDP with the syntax udp://host:port/prefix. This will 
 * send lines to the specified port, prefixed by the specified prefix and a space.
 */
function wfErrorLog( $text, $file ) {
        if ( substr( $file, 0, 4 ) == 'udp:' ) {
                if ( preg_match( '!^(tcp|udp):(?://)?\[([0-9a-fA-F:]+)\]:(\d+)(?:/(.*))?$!', $file, $m ) ) {
                        // IPv6 bracketed host
                        $protocol = $m[1];
                        $host = $m[2];
                        $port = $m[3];
                        $prefix = isset( $m[4] ) ? $m[4] : false;
                } elseif ( preg_match( '!^(tcp|udp):(?://)?([a-zA-Z0-9.-]+):(\d+)(?:/(.*))?$!', $file, $m ) ) {
                        $protocol = $m[1];
                        $host = $m[2];
                        $port = $m[3];
                        $prefix = isset( $m[4] ) ? $m[4] : false;
                } else {
                        throw new MWException( __METHOD__.": Invalid UDP specification" );
                }
                // Clean it up for the multiplexer
                if ( strval( $prefix ) !== '' ) {
                        $text = preg_replace( '/^/m', $prefix . ' ', $text );
                        if ( substr( $text, -1 ) != "\n" ) {
                                $text .= "\n";
                        }
                }

                $sock = fsockopen( "$protocol://$host", $port );
                if ( !$sock ) {
                        return;
                }
                fwrite( $sock, $text );
                fclose( $sock );
        } else {
                wfSuppressWarnings();
                $exists = file_exists( $file );
                $size = $exists ? filesize( $file ) : false;
                if ( !$exists || ( $size !== false && $size + strlen( $text ) < 0x7fffffff ) ) {
                        error_log( $text, 3, $file );
                }
                wfRestoreWarnings();
        }
}

/**
 * @todo document
 */
function wfLogProfilingData() {
        global $wgRequestTime, $wgDebugLogFile, $wgDebugRawPage, $wgRequest;
        global $wgProfiler, $wgProfileLimit, $wgUser;
        # Profiling must actually be enabled...
        if( !isset( $wgProfiler ) ) return;
        # Get total page request time
        $now = wfTime();
        $elapsed = $now - $wgRequestTime;
        # Only show pages that longer than $wgProfileLimit time (default is 0)
        if( $elapsed <= $wgProfileLimit ) return;
        $prof = wfGetProfilingOutput( $wgRequestTime, $elapsed );
        $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 unstub $wgUser at this late stage just for statistics purposes
        if( StubObject::isRealObject($wgUser) && $wgUser->isAnon() )
                $forward .= ' anon';
        $log = sprintf( "%s\t%04.3f\t%s\n",
          gmdate( 'YmdHis' ), $elapsed,
          urldecode( $wgRequest->getRequestURL() . $forward ) );
        if ( '' != $wgDebugLogFile && ( $wgRequest->getVal('action') != 'raw' || $wgDebugRawPage ) ) {
                wfErrorLog( $log . $prof, $wgDebugLogFile );
        }
}

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

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

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

/**
 * Return a Language object from $langcode
 * @param $langcode Mixed: either:
 *                  - a Language object
 *                  - code of the language to get the message for, if it is
 *                    a valid code create a language for that language, if
 *                    it is a string but not a valid code then make a basic
 *                    language object
 *                  - a boolean: if it's false then use the current users
 *                    language (as a fallback for the old parameter
 *                    functionality), or if it is true then use the wikis
 * @return Language object
 */
function wfGetLangObj( $langcode = false ){
        # Identify which language to get or create a language object for.
        if( $langcode instanceof Language )
                # Great, we already have the object!
                return $langcode;
                
        global $wgContLang;
        if( $langcode === $wgContLang->getCode() || $langcode === true )
                # $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 === $wgLang->getCode() || $langcode === false )
                # $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;
}

/**
 * Get a message from anywhere, for the current user language.
 *
 * Use wfMsgForContent() instead if the message should NOT
 * change depending on the user preferences.
 *
 * @param $key String: lookup key for the message, usually
 *    defined in languages/Language.php
 *
 * This function also takes extra optional parameters (not
 * shown in the function definition), which can by used to
 * insert variable text into the predefined message.
 */
function wfMsg( $key ) {
        $args = func_get_args();
        array_shift( $args );
        return wfMsgReal( $key, $args, true );
}

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

/**
 * Get a message from anywhere, for the current global language
 * set with $wgLanguageCode.
 *
 * Use this if the message should NOT change  dependent on the
 * language set in the user's preferences. This is the case for
 * most text written into logs, as well as link targets (such as
 * the name of the copyright policy page). Link titles, on the
 * other hand, should be shown in the UI language.
 *
 * Note that MediaWiki allows users to change the user interface
 * language in their preferences, but a single installation
 * typically only contains content in one language.
 *
 * Be wary of this distinction: If you use wfMsg() where you should
 * use wfMsgForContent(), a user of the software may have to
 * customize over 70 messages in order to, e.g., fix a link in every
 * possible language.
 *
 * @param $key String: lookup key for the message, usually
 *    defined in languages/Language.php
 */
function wfMsgForContent( $key ) {
        global $wgForceUIMsgAsContentMsg;
        $args = func_get_args();
        array_shift( $args );
        $forcontent = true;
        if( is_array( $wgForceUIMsgAsContentMsg ) &&
                in_array( $key, $wgForceUIMsgAsContentMsg ) )
                $forcontent = false;
        return wfMsgReal( $key, $args, true, $forcontent );
}

/**
 * Same as above except doesn't transform the message
 */
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 );
}

/**
 * Get a message from the language file, for the UI elements
 */
function wfMsgNoDB( $key ) {
        $args = func_get_args();
        array_shift( $args );
        return wfMsgReal( $key, $args, false );
}

/**
 * Get a message from the language file, for the content
 */
function wfMsgNoDBForContent( $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, false, $forcontent );
}


/**
 * Really get a message
 * @param $key String: key to get.
 * @param $args
 * @param $useDB Boolean
 * @param $transform Boolean: Whether or not to transform the message.
 * @param $forContent Boolean
 * @return String: the requested message.
 */
function wfMsgReal( $key, $args, $useDB = true, $forContent=false, $transform = true ) {
        global $wgMessageCache;
        wfProfileIn( __METHOD__ );
        $message = wfMsgGetKey( $key, $useDB, $forContent, false );
        $message = wfMsgReplaceArgs( $message, $args );
        if( $transform && is_object( $wgMessageCache ) ) {
          $message = $wgMessageCache->transform( $message, !$forContent );
        }
        wfProfileOut( __METHOD__ );
        return $message;
}

/**
 * This function provides the message source for messages to be edited which are *not* stored in the database.
 * @param $key String:
 */
function wfMsgWeirdKey ( $key ) {
        $source = wfMsgGetKey( $key, false, true, false );
        if ( wfEmptyMsg( $key, $source ) )
                return "";
        else
                return $source;
}

/**
 * Fetch a message string value, but don't replace any keys yet.
 * @param string $key
 * @param bool $useDB
 * @param string $langcode Code of the language to get the message for, or
 *                         behaves as a content language switch if it is a
 *                         boolean.
 * @return string
 * @private
 */
function wfMsgGetKey( $key, $useDB, $langCode = false, $transform = true ) {
        global $wgContLang, $wgMessageCache;

        wfRunHooks('NormalizeMessageKey', array(&$key, &$useDB, &$langCode, &$transform));
        
        # If $wgMessageCache isn't initialised yet, try to return something sensible.
        if( is_object( $wgMessageCache ) ) {
                $message = $wgMessageCache->get( $key, $useDB, $langCode );
                if ( $transform ) {
                        $message = $wgMessageCache->transform( $message );
                }
        } else {
                $lang = wfGetLangObj( $langCode );

                # MessageCache::get() does this already, Language::getMessage() doesn't
                # ISSUE: Should we try to handle "message/lang" here too?
                $key = str_replace( ' ' , '_' , $wgContLang->lcfirst( $key ) );

                if( is_object( $lang ) ) {
                        $message = $lang->getMessage( $key );
                } else {
                        $message = false;
                }
        }

        return $message;
}

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

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

        return $message;
}

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

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

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

        $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"
                        trigger_error( "wfMsgExt called with incorrect parameter key $arrayKey", E_USER_WARNING );
                } elseif( preg_match( '/^[0-9]+$/', $arrayKey ) && !in_array( $option,
                array( 'parse', 'parseinline', 'escape', 'escapenoentities',
                'replaceafter', 'parsemag', 'content' ) ) ) {
                        # A numeric index with unknown value
                        trigger_error( "wfMsgExt called with incorrect parameter $option", E_USER_WARNING );
                }
        }

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

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

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

        if( in_array('parse', $options, true ) ) {
                $string = $wgOut->parse( $string, true, !$forContent );
        } elseif ( in_array('parseinline', $options, true ) ) {
                $string = $wgOut->parse( $string, true, !$forContent );
                $m = array();
                if( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $string, $m ) ) {
                        $string = $m[1];
                }
        } elseif ( in_array('parsemag', $options, true ) ) {
                global $wgMessageCache;
                if ( isset( $wgMessageCache ) ) {
                        $string = $wgMessageCache->transform( $string,
                                !$forContent,
                                is_object( $langCode ) ? $langCode : null );
                }
        }

        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;
}


/**
 * Just like exit() but makes a note of it.
 * Commits open transactions except if the error parameter is set
 *
 * @deprecated Please return control to the caller or throw an exception
 */
function wfAbruptExit( $error = false ){
        static $called = false;
        if ( $called ){
                exit( -1 );
        }
        $called = true;

        $bt = wfDebugBacktrace();
        if( $bt ) {
                for($i = 0; $i < count($bt) ; $i++){
                        $file = isset($bt[$i]['file']) ? $bt[$i]['file'] : "unknown";
                        $line = isset($bt[$i]['line']) ? $bt[$i]['line'] : "unknown";
                        wfDebug("WARNING: Abrupt exit in $file at line $line\n");
                }
        } else {
                wfDebug("WARNING: Abrupt exit\n");
        }

        wfLogProfilingData();

        if ( !$error ) {
                wfGetLB()->closeAll();
        }
        exit( -1 );
}

/**
 * @deprecated Please return control the caller or throw an exception
 */
function wfErrorExit() {
        wfAbruptExit( true );
}

/**
 * Print a simple message and die, returning nonzero to the shell if any.
 * Plain die() fails to return nonzero to the shell if you pass a string.
 * @param string $msg
 */
function wfDie( $msg='' ) {
        echo $msg;
        die( 1 );
}

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

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

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

                $now = wfTime();
                $elapsed = $now - $wgRequestTime;

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

/**
 * Safety wrapper for debug_backtrace().
 *
 * With Zend Optimizer 3.2.0 loaded, this causes segfaults under somewhat
 * murky circumstances, which may be triggered in part by stub objects
 * or other fancy talkin'.
 *
 * Will return an empty array if Zend Optimizer is detected or if
 * debug_backtrace is disabled, otherwise the output from
 * debug_backtrace() (trimmed).
 *
 * @return array of backtrace information
 */
function wfDebugBacktrace() {
        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();
        }

        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'] . '::';
                $msg .= $call['function'] . '()';

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

        return $msg;
}


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


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

/**
 * @todo document
 */
function wfShowingResultsNum( $offset, $limit, $num ) {
        global $wgLang;
        return wfMsgExt( 'showingresultsnum', array( 'parseinline' ), $wgLang->formatNum( $limit ), 
                $wgLang->formatNum( $offset+1 ), $wgLang->formatNum( $num ) );
}

/**
 * Generate (prev x| next x) (20|50|100...) type links for paging
 * @param $offset string
 * @param $limit int
 * @param $link string
 * @param $query string, optional URL query parameter string
 * @param $atend bool, optional param for specified if this is the last page
 */
function wfViewPrevNext( $offset, $limit, $link, $query = '', $atend = false ) {
        global $wgLang;
        $fmtLimit = $wgLang->formatNum( $limit );
        # Get prev/next link display text
        $prev = wfMsgHtml( 'prevn', $fmtLimit );
        $next = wfMsgHtml( 'nextn', $fmtLimit );
        # Get prev/next link title text
        $pTitle = wfMsgExt( 'prevn-title', array('parsemag','escape'), $fmtLimit );
        $nTitle = wfMsgExt( 'nextn-title', array('parsemag','escape'), $fmtLimit );
        # Fetch the title object
        if( is_object( $link ) ) {
                $title =& $link;
        } else {
                $title = Title::newFromText( $link );
                if( is_null( $title ) ) {
                        return false;
                }
        }
        # Make 'previous' link
        if( 0 != $offset ) {
                $po = $offset - $limit;
                $po = max($po,0);
                $q = "limit={$limit}&offset={$po}";
                if( $query != '' ) {
                        $q .= '&'.$query;
                }
                $plink = '<a href="' . $title->escapeLocalUrl( $q ) . "\" title=\"{$pTitle}\" class=\"mw-prevlink\">{$prev}</a>";
        } else { 
                $plink = $prev;
        }
        # Make 'next' link
        $no = $offset + $limit;
        $q = "limit={$limit}&offset={$no}";
        if( $query != '' ) {
                $q .= '&'.$query;
        }
        if( $atend ) {
                $nlink = $next;
        } else {
                $nlink = '<a href="' . $title->escapeLocalUrl( $q ) . "\" title=\"{$nTitle}\" class=\"mw-nextlink\">{$next}</a>";
        }
        # Make links to set number of items per page
        $nums = $wgLang->pipeList( array( 
                wfNumLink( $offset, 20, $title, $query ),
                wfNumLink( $offset, 50, $title, $query ),
                wfNumLink( $offset, 100, $title, $query ),
                wfNumLink( $offset, 250, $title, $query ),
                wfNumLink( $offset, 500, $title, $query )
        ) );
        return wfMsg( 'viewprevnext', $plink, $nlink, $nums );
}

/**
 * Generate links for (20|50|100...) items-per-page links
 * @param $offset string
 * @param $limit int
 * @param $title Title
 * @param $query string, optional URL query parameter string
 */
function wfNumLink( $offset, $limit, $title, $query = '' ) {
        global $wgLang;
        if( $query == '' ) { 
                $q = '';
        } else { 
                $q = $query.'&';
        }
        $q .= "limit={$limit}&offset={$offset}";
        $fmtLimit = $wgLang->formatNum( $limit );
        $lTitle = wfMsgExt('shown-title',array('parsemag','escape'),$limit);
        $s = '<a href="' . $title->escapeLocalUrl( $q ) . "\" title=\"{$lTitle}\" class=\"mw-numlink\">{$fmtLimit}</a>";
        return $s;
}

/**
 * @todo document
 * @todo FIXME: we may want to blacklist some broken browsers
 *
 * @return bool Whereas client accept gzip compression
 */
function wfClientAcceptsGzip() {
        global $wgUseGzip;
        if( $wgUseGzip ) {
                # 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 ) ) return false;
                        wfDebug( " accepts gzip\n" );
                        return true;
                }
        }
        return false;
}

/**
 * Obtain the offset and limit values from the request string;
 * used in special pages
 *
 * @param $deflimit Default limit if none supplied
 * @param $optionname Name of a user preference to check against
 * @return array
 *
 */
function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
        global $wgRequest;
        return $wgRequest->getLimitOffset( $deflimit, $optionname );
}

/**
 * Escapes the given text so that it may be output using addWikiText()
 * without any linking, formatting, etc. making its way through. This
 * is achieved by substituting certain characters with HTML entities.
 * As required by the callers, <nowiki> is not used. It currently does
 * not filter out characters which have special meaning only at the
 * start of a line, such as "*".
 *
 * @param string $text Text to be escaped
 */
function wfEscapeWikiText( $text ) {
        $text = str_replace(
                array( '[',     '|',      ']',     '\'',    'ISBN ',     'RFC ',     '://',     "\n=",     '{{' ), # }}
                array( '&#91;', '&#124;', '&#93;', '&#39;', 'ISBN&#32;', 'RFC&#32;', '&#58;//', "\n&#61;", '&#123;&#123;' ),
                htmlspecialchars($text) );
        return $text;
}

/**
 * @todo document
 */
function wfQuotedPrintable( $string, $charset = '' ) {
        # Probably incomplete; see RFC 2045
        if( empty( $charset ) ) {
                global $wgInputEncoding;
                $charset = $wgInputEncoding;
        }
        $charset = strtoupper( $charset );
        $charset = str_replace( 'ISO-8859', 'ISO8859', $charset ); // ?

        $illegal = '\x00-\x08\x0b\x0c\x0e-\x1f\x7f-\xff=';
        $replace = $illegal . '\t ?_';
        if( !preg_match( "/[$illegal]/", $string ) ) return $string;
        $out = "=?$charset?Q?";
        $out .= preg_replace( "/([$replace])/e", 'sprintf("=%02X",ord("$1"))', $string );
        $out .= '?=';
        return $out;
}


/**
 * @todo document
 * @return float
 */
function wfTime() {
        return microtime(true);
}

/**
 * Sets dest to source and returns the original value of dest
 * If source is NULL, it just returns the value, it doesn't set the variable
 */
function wfSetVar( &$dest, $source ) {
        $temp = $dest;
        if ( !is_null( $source ) ) {
                $dest = $source;
        }
        return $temp;
}

/**
 * As for wfSetVar except setting a bit
 */
function wfSetBit( &$dest, $bit, $state = true ) {
        $temp = (bool)($dest & $bit );
        if ( !is_null( $state ) ) {
                if ( $state ) {
                        $dest |= $bit;
                } else {
                        $dest &= ~$bit;
                }
        }
        return $temp;
}

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

        $cgi = '';
        foreach ( $array1 as $key => $value ) {
                if ( '' !== $value ) {
                        if ( '' != $cgi ) {
                                $cgi .= '&';
                        }
                        if(is_array($value))
                        {
                                $firstTime = true;
                                foreach($value as $v)
                                {
                                        $cgi .= ($firstTime ? '' : '&') .
                                                urlencode( $key . '[]' ) . '=' .
                                                urlencode( $v );
                                        $firstTime = false;
                                }
                        }
                        else
                                $cgi .= urlencode( $key ) . '=' .
                                        urlencode( $value );
                }
        }
        return $cgi;
}

/**
 * This is the logical opposite of wfArrayToCGI(): it accepts a query string as
 * its argument and returns the same string in array form.  This allows compa-
 * tibility with legacy functions that accept raw query strings instead of nice
 * arrays.  Of course, keys and values are urldecode()d.  Don't try passing in-
 * valid query strings, or it will explode.
 *
 * @param $query string Query string
 * @return array Array version of input
 */
function wfCgiToArray( $query ) {
        if( isset( $query[0] ) and $query[0] == '?' ) {
                $query = substr( $query, 1 );
        }
        $bits = explode( '&', $query );
        $ret = array();
        foreach( $bits as $bit ) {
                if( $bit === '' ) {
                        continue;
                }
                list( $key, $value ) = explode( '=', $bit );
                $key = urldecode( $key );
                $value = urldecode( $value );
                $ret[$key] = $value;
        }
        return $ret;
}

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

/**
 * Expand a potentially local URL to a fully-qualified URL.
 * Assumes $wgServer is correct. :)
 * @param string $url, either fully-qualified or a local path + query
 * @return string Fully-qualified URL
 */
function wfExpandUrl( $url ) {
        if( substr( $url, 0, 1 ) == '/' ) {
                global $wgServer;
                return $wgServer . $url;
        } else {
                return $url;
        }
}

/**
 * This is obsolete, use SquidUpdate::purge()
 * @deprecated
 */
function wfPurgeSquidServers ($urlArr) {
        SquidUpdate::purge( $urlArr );
}

/**
 * Windows-compatible version of escapeshellarg()
 * Windows doesn't recognise single-quotes in the shell, but the escapeshellarg()
 * function puts single quotes in regardless of OS.
 *
 * Also fixes the locale problems on Linux in PHP 5.2.6+ (bug backported to 
 * earlier distro releases of PHP)
 */
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
                        // Ref: http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
                        // Double the backslashes before any double quotes. Escape the double quotes.
                        $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
                        $arg = '';
                        $delim = false;
                        foreach ( $tokens as $token ) {
                                if ( $delim ) {
                                        $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
                                } else {
                                        $arg .= $token;
                                }
                                $delim = !$delim;
                        }
                        // 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;
}

/**
 * wfMerge attempts to merge differences between three texts.
 * Returns true for a clean merge and false for failure or a conflict.
 */
function wfMerge( $old, $mine, $yours, &$result ){
        global $wgDiff3;

        # This check may also protect against code injection in
        # case of broken installations.
        if( !$wgDiff3 || !file_exists( $wgDiff3 ) ) {
                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 == false ) {
                wfDebug( "Unexpected null result from diff3. Command: $cmd\n" );
                $conflict = true;
        }
        return ! $conflict;
}

/**
 * Returns unified plain-text diff of two texts.
 * Useful for machine processing of diffs.
 * @param $before string The text before the changes.
 * @param $after string The text after the changes.
 * @param $params string Command-line options for the diff command.
 * @return string Unified diff of $before and $after
 */
function wfDiff( $before, $after, $params = '-u' ) {
        global $wgDiff;

        # This check may also protect against code injection in
        # case of broken installations.
        if( !file_exists( $wgDiff ) ){
                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;
}

/**
 * A wrapper around the PHP function var_export().
 * Either print it or add it to the regular output ($wgOut).
 *
 * @param $var A PHP variable to dump.
 */
function wfVarDump( $var ) {
        global $wgOut;
        $s = str_replace("\n","<br />\n", var_export( $var, true ) . "\n");
        if ( headers_sent() || !@is_object( $wgOut ) ) {
                print $s;
        } else {
                $wgOut->addHTML( $s );
        }
}

/**
 * Provide a simple HTTP error.
 */
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 PUBLIC \"-//IETF//DTD HTML 2.0//EN\">".
                "<html><head><title>" .
                htmlspecialchars( $label ) .
                "</title></head><body><h1>" .
                htmlspecialchars( $label ) .
                "</h1><p>" .
                nl2br( htmlspecialchars( $desc ) ) .
                "</p></body></html>\n";
}

/**
 * Clear away any user-level output buffers, discarding contents.
 *
 * Suitable for 'starting afresh', for instance when streaming
 * relatively large amounts of data without buffering, or wanting to
 * output image files without ob_gzhandler's compression.
 *
 * The optional $resetGzipEncoding parameter controls suppression of
 * the Content-Encoding header sent by ob_gzhandler; by default it
 * is left. See comments for wfClearOutputBuffers() for why it would
 * be used.
 *
 * Note that some PHP configuration options may add output buffer
 * layers which cannot be removed; these are left in place.
 *
 * @param bool $resetGzipEncoding
 */
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.
                                header( 'Content-Encoding:' );
                                break;
                        }
                }
        }
}

/**
 * More legible than passing a 'false' parameter to wfResetOutputBuffers():
 *
 * Clear away output buffers, but keep the Content-Encoding header
 * produced by ob_gzhandler, if any.
 *
 * This should be used for HTTP 304 responses, where you need to
 * preserve the Content-Encoding header of the real result, but
 * also need to suppress the output of ob_gzhandler to keep to spec
 * and avoid breaking Firefox in rare cases where the headers and
 * body are broken over two packets.
 */
function wfClearOutputBuffers() {
        wfResetOutputBuffers( false );
}

/**
 * Converts an Accept-* header into an array mapping string values to quality
 * factors
 */
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 ) {
                # FIXME: doesn't deal with params like 'text/html; level=1'
                @list( $value, $qpart ) = explode( ';', trim( $part ) );
                $match = array();
                if( !isset( $qpart ) ) {
                        $prefs[$value] = 1.0;
                } elseif( preg_match( '/q\s*=\s*(\d*\.\d+)/', $qpart, $match ) ) {
                        $prefs[$value] = floatval($match[1]);
                }
        }

        return $prefs;
}

/**
 * Checks if a given MIME type matches any of the keys in the given
 * array. Basic wildcards are accepted in the array keys.
 *
 * Returns the matching MIME type (or wildcard) if a match, otherwise
 * NULL if no match.
 *
 * @param string $type
 * @param array $avail
 * @return string
 * @private
 */
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;
                }
        }
}

/**
 * Returns the 'best' match between a client's requested internet media types
 * and the server's list of available types. Each list should be an associative
 * array of type to preference (preference is a float between 0.0 and 1.0).
 * Wildcards in the types are acceptable.
 *
 * @param array $cprefs Client's acceptable type list
 * @param array $sprefs Server's offered types
 * @return string
 *
 * @todo FIXME: doesn't handle params like 'text/plain; charset=UTF-8'
 * XXX: generalize to negotiate other stuff
 */
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;
}

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

/**
 * Convenience function; returns MediaWiki timestamp for the present time.
 * @return string
 */
function wfTimestampNow() {
        # return NOW
        return wfTimestamp( TS_MW, time() );
}

/**
 * Reference-counted warning suppression
 */
function wfSuppressWarnings( $end = false ) {
        static $suppressCount = 0;
        static $originalLevel = false;

        if ( $end ) {
                if ( $suppressCount ) {
                        --$suppressCount;
                        if ( !$suppressCount ) {
                                error_reporting( $originalLevel );
                        }
                }
        } else {
                if ( !$suppressCount ) {
                        $originalLevel = error_reporting( E_ALL & ~( E_WARNING | E_NOTICE ) );
                }
                ++$suppressCount;
        }
}

/**
 * Restore error level to previous value
 */
function wfRestoreWarnings() {
        wfSuppressWarnings( true );
}

# Autodetect, convert and provide timestamps of various types

/**
 * Unix time - the number of seconds since 1970-01-01 00:00:00 UTC
 */
define('TS_UNIX', 0);

/**
 * MediaWiki concatenated string timestamp (YYYYMMDDHHMMSS)
 */
define('TS_MW', 1);

/**
 * MySQL DATETIME (YYYY-MM-DD HH:MM:SS)
 */
define('TS_DB', 2);

/**
 * RFC 2822 format, for E-mail and HTTP headers
 */
define('TS_RFC2822', 3);

/**
 * ISO 8601 format with no timezone: 1986-02-09T20:00:00Z
 *
 * This is used by Special:Export
 */
define('TS_ISO_8601', 4);

/**
 * An Exif timestamp (YYYY:MM:DD HH:MM:SS)
 *
 * @see http://exif.org/Exif2-2.PDF The Exif 2.2 spec, see page 28 for the
 *       DateTime tag and page 36 for the DateTimeOriginal and
 *       DateTimeDigitized tags.
 */
define('TS_EXIF', 5);

/**
 * Oracle format time.
 */
define('TS_ORACLE', 6);

/**
 * Postgres format time.
 */
define('TS_POSTGRES', 7);

/**
 * DB2 format time
 */
define('TS_DB2', 8);

/**
 * @param mixed $outputtype A timestamp in one of the supported formats, the
 *                          function will autodetect which format is supplied
 *                          and act accordingly.
 * @return string Time in the format specified in $outputtype
 */
function wfTimestamp($outputtype=TS_UNIX,$ts=0) {
        $uts = 0;
        $da = array();
        if ($ts==0) {
                $uts=time();
        } elseif (preg_match('/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)$/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;
        } elseif (preg_match('/^\d{1,2}-...-\d\d(?:\d\d)? \d\d\.\d\d\.\d\d/', $ts)) {
                # TS_ORACLE
                $uts = strtotime(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, $da)) {
                # TS_ISO_8601
        } elseif (preg_match('/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)\.*\d*[\+\- ](\d\d)$/',$ts,$da)) {
                # TS_POSTGRES
        } elseif (preg_match('/^(\d{4})\-(\d\d)\-(\d\d) (\d\d):(\d\d):(\d\d)\.*\d* GMT$/',$ts,$da)) {
                # TS_POSTGRES
        } else {
                # Bogus value; fall back to the epoch...
                wfDebug("wfTimestamp() fed bogus time value: $outputtype; $ts\n");
                $uts = 0;
        }

        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]);
        }

        switch($outputtype) {
                case TS_UNIX:
                        return $uts;
                case TS_MW:
                        return gmdate( 'YmdHis', $uts );
                case TS_DB:
                        return gmdate( 'Y-m-d H:i:s', $uts );
                case TS_ISO_8601:
                        return gmdate( 'Y-m-d\TH:i:s\Z', $uts );
                // This shouldn't ever be used, but is included for completeness
                case TS_EXIF:
                        return gmdate(  'Y:m:d H:i:s', $uts );
                case TS_RFC2822:
                        return gmdate( 'D, d M Y H:i:s', $uts ) . ' GMT';
                case TS_ORACLE:
                        return gmdate( 'd-M-y h.i.s A', $uts) . ' +00:00';
                case TS_POSTGRES:
                        return gmdate( 'Y-m-d H:i:s', $uts) . ' GMT';
                case TS_DB2:
                        return gmdate( 'Y-m-d H:i:s', $uts);
                default:
                        throw new MWException( 'wfTimestamp() called with illegal output type.');
        }
}

/**
 * Return a formatted timestamp, or null if input is null.
 * For dealing with nullable timestamp columns in the database.
 * @param int $outputtype
 * @param string $ts
 * @return string
 */
function wfTimestampOrNull( $outputtype = TS_UNIX, $ts = null ) {
        if( is_null( $ts ) ) {
                return null;
        } else {
                return wfTimestamp( $outputtype, $ts );
        }
}

/**
 * Check if the operating system is Windows
 *
 * @return bool True if it's Windows, False otherwise.
 */
function wfIsWindows() {
        if (substr(php_uname(), 0, 7) == 'Windows') {
                return true;
        } else {
                return false;
        }
}

/**
 * Swap two variables
 */
function swap( &$x, &$y ) {
        $z = $x;
        $x = $y;
        $y = $z;
}

function wfGetCachedNotice( $name ) {
        global $wgOut, $wgRenderHashAppend, $parserMemc;
        $fname = 'wfGetCachedNotice';
        wfProfileIn( $fname );

        $needParse = false;

        if( $name === 'default' ) {
                // special case
                global $wgSiteNotice;
                $notice = $wgSiteNotice;
                if( empty( $notice ) ) {
                        wfProfileOut( $fname );
                        return false;
                }
        } else {
                $notice = wfMsgForContentNoTrans( $name );
                if( wfEmptyMsg( $name, $notice ) || $notice == '-' ) {
                        wfProfileOut( $fname );
                        return( false );
                }
        }

        // Use the extra hash appender to let eg SSL variants separately cache.
        $key = wfMemcKey( $name . $wgRenderHashAppend );
        $cachedNotice = $parserMemc->get( $key );
        if( is_array( $cachedNotice ) ) {
                if( md5( $notice ) == $cachedNotice['hash'] ) {
                        $notice = $cachedNotice['html'];
                } else {
                        $needParse = true;
                }
        } else {
                $needParse = true;
        }

        if( $needParse ) {
                if( is_object( $wgOut ) ) {
                        $parsed = $wgOut->parse( $notice );
                        $parserMemc->set( $key, array( 'html' => $parsed, 'hash' => md5( $notice ) ), 600 );
                        $notice = $parsed;
                } else {
                        wfDebug( 'wfGetCachedNotice called for ' . $name . ' with no $wgOut available'."\n" );
                        $notice = '';
                }
        }

        wfProfileOut( $fname );
        return $notice;
}

function wfGetNamespaceNotice() {
        global $wgTitle;

        # Paranoia
        if ( !isset( $wgTitle ) || !is_object( $wgTitle ) )
                return "";

        $fname = 'wfGetNamespaceNotice';
        wfProfileIn( $fname );

        $key = "namespacenotice-" . $wgTitle->getNsText();
        $namespaceNotice = wfGetCachedNotice( $key );
        if ( $namespaceNotice && substr ( $namespaceNotice , 0 ,7 ) != "<p>&lt;" ) {
                 $namespaceNotice = '<div id="namespacebanner">' . $namespaceNotice . "</div>";
        } else {
                $namespaceNotice = "";
        }

        wfProfileOut( $fname );
        return $namespaceNotice;
}

function wfGetSiteNotice() {
        global $wgUser, $wgSiteNotice;
        $fname = 'wfGetSiteNotice';
        wfProfileIn( $fname );
        $siteNotice = '';

        if( wfRunHooks( 'SiteNoticeBefore', array( &$siteNotice ) ) ) {
                if( is_object( $wgUser ) && $wgUser->isLoggedIn() ) {
                        $siteNotice = wfGetCachedNotice( 'sitenotice' );
                } else {
                        $anonNotice = wfGetCachedNotice( 'anonnotice' );
                        if( !$anonNotice ) {
                                $siteNotice = wfGetCachedNotice( 'sitenotice' );
                        } else {
                                $siteNotice = $anonNotice;
                        }
                }
                if( !$siteNotice ) {
                        $siteNotice = wfGetCachedNotice( 'default' );
                }
        }

        wfRunHooks( 'SiteNoticeAfter', array( &$siteNotice ) );
        wfProfileOut( $fname );
        return $siteNotice;
}

/**
 * BC wrapper for MimeMagic::singleton()
 * @deprecated
 */
function &wfGetMimeMagic() {
        return MimeMagic::singleton();
}

/**
 * Tries to get the system directory for temporary files.
 * The TMPDIR, TMP, and TEMP environment variables are checked in sequence,
 * and if none are set /tmp is returned as the generic Unix default.
 *
 * NOTE: When possible, use the tempfile() function to create temporary
 * files to avoid race conditions on file creation, etc.
 *
 * @return string
 */
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;
                }
        }
        # Hope this is Unix of some kind!
        return '/tmp';
}

/**
 * Make directory, and make all parent directories if they don't exist
 * 
 * @param string $dir Full path to directory to create
 * @param int $mode Chmod value to use, default is $wgDirectoryMode
 * @return bool
 */
function wfMkdirParents( $dir, $mode = null ) {
        global $wgDirectoryMode;

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

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

        if ( !is_writable( $dir ) ) {
                return false;
        }
        return mkdir( $dir, $mode, true );  // PHP5 <3
}

/**
 * Increment a statistics counter
 */
function wfIncrStats( $key ) {
        global $wgStatsMethod;

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

/**
 * @param mixed $nr The number to format
 * @param int $acc The number of digits after the decimal point, default 2
 * @param bool $round Whether or not to round the value, default true
 * @return float
 */
function wfPercent( $nr, $acc = 2, $round = true ) {
        $ret = sprintf( "%.${acc}f", $nr );
        return $round ? round( $ret, $acc ) . '%' : "$ret%";
}

/**
 * Encrypt a username/password.
 *
 * @param string $userid ID of the user
 * @param string $password Password of the user
 * @return string Hashed password
 * @deprecated Use User::crypt() or User::oldCrypt() instead
 */
function wfEncryptPassword( $userid, $password ) {
        wfDeprecated(__FUNCTION__);
        # Just wrap around User::oldCrypt()
        return User::oldCrypt($password, $userid);
}

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

/**
 * Since wfMsg() and co suck, they don't return false if the message key they
 * looked up didn't exist but a XHTML string, this function checks for the
 * nonexistance of messages by looking at wfMsg() output
 *
 * @param $msg      The message key looked up
 * @param $wfMsgOut The output of wfMsg*()
 * @return bool
 */
function wfEmptyMsg( $msg, $wfMsgOut ) {
        return $wfMsgOut === htmlspecialchars( "<$msg>" );
}

/**
 * Find out whether or not a mixed variable exists in a string
 *
 * @param mixed  needle
 * @param string haystack
 * @return bool
 */
function in_string( $needle, $str ) {
        return strpos( $str, $needle ) !== false;
}

function wfSpecialList( $page, $details ) {
        global $wgContLang;
        $details = $details ? ' ' . $wgContLang->getDirMark() . "($details)" : "";
        return $page . $details;
}

/**
 * Returns a regular expression of url protocols
 *
 * @return string
 */
function wfUrlProtocols() {
        global $wgUrlProtocols;

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

                return implode( '|', $protocols );
        } else {
                return $wgUrlProtocols;
        }
}

/**
 * Safety wrapper around ini_get() for boolean settings.
 * The values returned from ini_get() are pre-normalized for settings
 * set via php.ini or php_flag/php_admin_flag... but *not*
 * for those set via php_value/php_admin_value.
 *
 * It's fairly common for people to use php_value instead of php_flag,
 * which can leave you with an 'off' setting giving a false positive
 * for code that just takes the ini_get() return value as a boolean.
 *
 * To make things extra interesting, setting via php_value accepts
 * "true" and "yes" as true, but php.ini and php_flag consider them false. :)
 * Unrecognized values go false... again opposite PHP's own coercion
 * from string to bool.
 *
 * Luckily, 'properly' set settings will always come back as '0' or '1',
 * so we only have to worry about them and the 'improper' settings.
 *
 * I frickin' hate PHP... :P
 *
 * @param string $setting
 * @return bool
 */
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
}

/**
 * Execute a shell command, with time and memory limits mirrored from the PHP
 * configuration if supported.
 * @param $cmd Command line, properly escaped for shell.
 * @param &$retval optional, will receive the program's exit code.
 *                 (non-zero is usually failure)
 * @return collected stdout as a string (trailing newlines stripped)
 */
function wfShellExec( $cmd, &$retval=null ) {
        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 = true;
                }
                $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 = true;
                }
        }
        if ( $disabled ) {
                $retval = 1;
                return "Unable to run external programs in safe mode.";
        }

        wfInitShellLocale();

        if ( 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 = escapeshellarg( $script ) . " $time $mem $filesize " . escapeshellarg( $cmd );
                        }
                }
        } elseif ( php_uname( 's' ) == 'Windows NT' ) {
                # This is a hack to work around PHP's flawed invocation of cmd.exe
                # http://news.php.net/php.internals/21796
                $cmd = '"' . $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;
}

/**
 * Workaround for http://bugs.php.net/bug.php?id=45132
 * escapeshellarg() destroys non-ASCII characters if LANG is not a UTF-8 locale
 */
function wfInitShellLocale() {
        static $done = false;
        if ( $done ) return;
        $done = true;
        global $wgShellLocale;
        if ( !wfIniGetBool( 'safe_mode' ) ) {
                putenv( "LC_CTYPE=$wgShellLocale" );
                setlocale( LC_CTYPE, $wgShellLocale );
        }
}

/**
 * This function works like "use VERSION" in Perl, the program will die with a
 * backtrace if the current version of PHP is less than the version provided
 *
 * This is useful for extensions which due to their nature are not kept in sync
 * with releases, and might depend on other versions of PHP than the main code
 *
 * Note: PHP might die due to parsing errors in some cases before it ever
 *       manages to call this function, such is life
 *
 * @see perldoc -f use
 *
 * @param mixed $version The version to check, can be a string, an integer, or
 *                       a float
 */
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" );
}

/**
 * This function works like "use VERSION" in Perl except it checks the version
 * of MediaWiki, the program will die with a backtrace if the current version
 * of MediaWiki is less than the version provided.
 *
 * This is useful for extensions which due to their nature are not kept in sync
 * with releases
 *
 * @see perldoc -f use
 *
 * @param mixed $version The version to check, can be a string, an integer, or
 *                       a float
 */
function wfUseMW( $req_ver ) {
        global $wgVersion;

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

/**
 * @deprecated use StringUtils::escapeRegexReplacement
 */
function wfRegexReplacement( $string ) {
        return StringUtils::escapeRegexReplacement( $string );
}

/**
 * Return the final portion of a pathname.
 * Reimplemented because PHP5's basename() is buggy with multibyte text.
 * http://bugs.php.net/bug.php?id=33898
 *
 * PHP's basename() only considers '\' a pathchar on Windows and Netware.
 * We'll consider it so always, as we don't want \s in our Unix paths either.
 *
 * @param string $path
 * @param string $suffix to remove if present
 * @return string
 */
function wfBaseName( $path, $suffix='' ) {
        $encSuffix = ($suffix == '')
                ? ''
                : ( '(?:' . preg_quote( $suffix, '#' ) . ')?' );
        $matches = array();
        if( preg_match( "#([^/\\\\]*?){$encSuffix}[/\\\\]*$#", $path, $matches ) ) {
                return $matches[1];
        } else {
                return '';
        }
}

/**
 * Generate a relative path name to the given file.
 * May explode on non-matching case-insensitive paths,
 * funky symlinks, etc.
 *
 * @param string $path Absolute destination path including target filename
 * @param string $from Absolute source path, directory only
 * @return string
 */
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 );
}

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

/**
 * Merge arrays in the style of getUserPermissionsErrors, with duplicate removal
 * e.g.
 *      wfMergeErrorArrays( 
 *              array( array( 'x' ) ), 
 *              array( array( 'x', '2' ) ), 
 *              array( array( 'x' ) ), 
 *              array( array( 'y') )
 *      );
 * returns:
 *              array( 
 *              array( 'x', '2' ),
 *              array( 'x' ),
 *              array( 'y' )
 *      )
 */
function wfMergeErrorArrays(/*...*/) {
        $args = func_get_args();
        $out = array();
        foreach ( $args as $errors ) {
                foreach ( $errors as $params ) {
                        $spec = implode( "\t", $params );
                        $out[$spec] = $params;
                }
        }
        return array_values( $out );
}

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

        return $bits;
}

/**
 * Make a URL index, appropriate for the el_index field of externallinks.
 */
function wfMakeUrlIndex( $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'];
        return $index;
}

/**
 * Do any deferred updates and clear the list
 * TODO: This could be in Wiki.php if that class made any sense at all
 */
function wfDoUpdates()
{
        global $wgPostCommitUpdateList, $wgDeferredUpdateList;
        foreach ( $wgDeferredUpdateList as $update ) {
                $update->doUpdate();
        }
        foreach ( $wgPostCommitUpdateList as $update ) {
                $update->doUpdate();
        }
        $wgDeferredUpdateList = array();
        $wgPostCommitUpdateList = array();
}

/**
 * @deprecated use StringUtils::explodeMarkup
 */
function wfExplodeMarkup( $separator, $text ) {
        return StringUtils::explodeMarkup( $separator, $text );
}

/**
 * Convert an arbitrarily-long digit string from one numeric base
 * to another, optionally zero-padding to a minimum column width.
 *
 * Supports base 2 through 36; digit values 10-36 are represented
 * as lowercase letters a-z. Input is case-insensitive.
 *
 * @param $input string of digits
 * @param $sourceBase int 2-36
 * @param $destBase int 2-36
 * @param $pad int 1 or greater
 * @param $lowercase bool
 * @return string or false on invalid input
 */
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 );
}

/**
 * Create an object with a given name and an array of construct parameters
 * @param string $name
 * @param array $p parameters
 */
function wfCreateObject( $name, $p ){
        $p = array_values( $p );
        switch ( count( $p ) ) {
                case 0:
                        return new $name;
                case 1:
                        return new $name( $p[0] );
                case 2:
                        return new $name( $p[0], $p[1] );
                case 3:
                        return new $name( $p[0], $p[1], $p[2] );
                case 4:
                        return new $name( $p[0], $p[1], $p[2], $p[3] );
                case 5:
                        return new $name( $p[0], $p[1], $p[2], $p[3], $p[4] );
                case 6:
                        return new $name( $p[0], $p[1], $p[2], $p[3], $p[4], $p[5] );
                default:
                        throw new MWException( "Too many arguments to construtor in wfCreateObject" );
        }
}

/**
 * Alias for modularized function
 * @deprecated Use Http::get() instead
 */
function wfGetHTTP( $url, $timeout = 'default' ) {
        wfDeprecated(__FUNCTION__);
        return Http::get( $url, $timeout );
}

/**
 * Alias for modularized function
 * @deprecated Use Http::isLocalURL() instead
 */
function wfIsLocalURL( $url ) {
        wfDeprecated(__FUNCTION__);
        return Http::isLocalURL( $url );
}

function wfHttpOnlySafe() {
        global $wgHttpOnlyBlacklist;
        if( !version_compare("5.2", PHP_VERSION, "<") )
                return false;

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

        return true;
}

/**
 * Initialise php session
 */
function wfSetupSession() {
        global $wgSessionsInMemcached, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $wgCookieHttpOnly;
        if( $wgSessionsInMemcached ) {
                require_once( 'MemcachedSessions.php' );
        } elseif( 'files' != ini_get( 'session.save_handler' ) ) {
                # If it's left on 'user' or another setting from another
                # application, it will end up failing. Try to recover.
                ini_set ( 'session.save_handler', 'files' );
        }
        $httpOnlySafe = wfHttpOnlySafe();
        wfDebugLog( 'cookie',
                'session_set_cookie_params: "' . implode( '", "',
                        array(
                                0,
                                $wgCookiePath,
                                $wgCookieDomain,
                                $wgCookieSecure,
                                $httpOnlySafe && $wgCookieHttpOnly ) ) . '"' );
        if( $httpOnlySafe && $wgCookieHttpOnly ) {
                session_set_cookie_params( 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $wgCookieHttpOnly );
        } else {
                // PHP 5.1 throws warnings if you pass the HttpOnly parameter for 5.2.
                session_set_cookie_params( 0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure );
        }
        session_cache_limiter( 'private, must-revalidate' );
        wfSuppressWarnings();
        session_start();
        wfRestoreWarnings();
}

/**
 * Get an object from the precompiled serialized directory
 *
 * @return mixed The variable on success, false on failure
 */
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 wfGetCaller( $level = 2 ) {
        $backtrace = wfDebugBacktrace();
        if ( isset( $backtrace[$level] ) ) {
                return wfFormatStackFrame($backtrace[$level]);
        } else {
                $caller = 'unknown';
        }
        return $caller;
}

/** Return a string consisting all callers in stack, somewhat useful sometimes for profiling specific points */
function wfGetAllCallers() {
        return implode('/', array_map('wfFormatStackFrame',array_reverse(wfDebugBacktrace())));
}

/** Return a string representation of frame */
function wfFormatStackFrame($frame) {
        return isset( $frame["class"] )?
                $frame["class"]."::".$frame["function"]:
                $frame["function"];
}

/**
 * Get a cache key
 */
function wfMemcKey( /*... */ ) {
        $args = func_get_args();
        $key = wfWikiID() . ':' . implode( ':', $args );
        return $key;
}

/**
 * Get a cache key for a foreign DB
 */
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;
}

/**
 * Get an ASCII string identifying this wiki
 * This is used as a prefix in memcached keys
 */
function wfWikiID( $db = null ) {
        if( $db instanceof Database ) {
                return $db->getWikiID();
        } else {
        global $wgDBprefix, $wgDBname;
                if ( $wgDBprefix ) {
                        return "$wgDBname-$wgDBprefix";
                } else {
                        return $wgDBname;
                }
        }
}

/**
 * Split a wiki ID into DB name and table prefix
 */
function wfSplitWikiID( $wiki ) {
        $bits = explode( '-', $wiki, 2 );
        if ( count( $bits ) < 2 ) {
                $bits[] = '';
        }
        return $bits;
}

/*
 * Get a Database object.
 * @param integer $db Index of the connection to get. May be DB_MASTER for the
 *                master (for write queries), DB_SLAVE for potentially lagged
 *                read queries, or an integer >= 0 for a particular server.
 *
 * @param mixed $groups Query groups. An array of group names that this query
 *              belongs to. May contain a single string if the query is only
 *              in one group.
 *
 * @param string $wiki The wiki ID, or false for the current wiki
 *
 * Note: multiple calls to wfGetDB(DB_SLAVE) during the course of one request
 * will always return the same object, unless the underlying connection or load
 * balancer is manually destroyed.
 */
function &wfGetDB( $db, $groups = array(), $wiki = false ) {
        return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
}

/**
 * Get a load balancer object.
 *
 * @param array $groups List of query groups
 * @param string $wiki Wiki ID, or false for the current wiki
 * @return LoadBalancer
 */
function wfGetLB( $wiki = false ) {
        return wfGetLBFactory()->getMainLB( $wiki );
}

/**
 * Get the load balancer factory object
 */
function &wfGetLBFactory() {
        return LBFactory::singleton();
}

/**
 * Find a file.
 * Shortcut for RepoGroup::singleton()->findFile()
 * @param mixed $title Title object or string. May be interwiki.
 * @param mixed $time Requested time for an archived image, or false for the
 *                    current version. An image object will be returned which
 *                    was created at the specified time.
 * @param mixed $flags FileRepo::FIND_ flags
 * @param boolean $bypass Bypass the file cache even if it could be used
 * @return File, or false if the file does not exist
 */
function wfFindFile( $title, $time = false, $flags = 0, $bypass = false ) {
        if( !$time && !$flags && !$bypass ) {
                return FileCache::singleton()->findFile( $title );
        } else {
                return RepoGroup::singleton()->findFile( $title, $time, $flags );
        }
}

/**
 * Get an object referring to a locally registered file.
 * Returns a valid placeholder object if the file does not exist.
 */
function wfLocalFile( $title ) {
        return RepoGroup::singleton()->getLocalRepo()->newFile( $title );
}

/**
 * Should low-performance queries be disabled?
 *
 * @return bool
 */
function wfQueriesMustScale() {
        global $wgMiserMode;
        return $wgMiserMode
                || ( SiteStats::pages() > 100000
                && SiteStats::edits() > 1000000
                && SiteStats::users() > 10000 );
}

/**
 * Get the path to a specified script file, respecting file
 * extensions; this is a wrapper around $wgScriptExtension etc.
 *
 * @param string $script Script filename, sans extension
 * @return string
 */
function wfScript( $script = 'index' ) {
        global $wgScriptPath, $wgScriptExtension;
        return "{$wgScriptPath}/{$script}{$wgScriptExtension}";
}

/**
 * Convenience function converts boolean values into "true"
 * or "false" (string) values
 *
 * @param bool $value
 * @return string
 */
function wfBoolToStr( $value ) {
        return $value ? 'true' : 'false';
}

/**
 * Load an extension messages file
 *
 * @param string $extensionName Name of extension to load messages from\for.
 * @param string $langcode Language to load messages for, or false for default
 *                         behvaiour (en, content language and user language).
 * @since r24808 (v1.11) Using this method of loading extension messages will not work
 * on MediaWiki prior to that
 */
function wfLoadExtensionMessages( $extensionName, $langcode = false ) {
        global $wgExtensionMessagesFiles, $wgMessageCache, $wgLang, $wgContLang;

        #For recording whether extension message files have been loaded in a given language.
        static $loaded = array();

        if( !array_key_exists( $extensionName, $loaded ) ) {
                $loaded[$extensionName] = array();
        }

        if ( !isset($wgExtensionMessagesFiles[$extensionName]) ) {
                throw new MWException( "Messages file for extensions $extensionName is not defined" );
        }

        if( !$langcode && !array_key_exists( '*', $loaded[$extensionName] ) ) {
                # Just do en, content language and user language.
                $wgMessageCache->loadMessagesFile( $wgExtensionMessagesFiles[$extensionName], false );
                # Mark that they have been loaded.
                $loaded[$extensionName]['en'] = true;
                $loaded[$extensionName][$wgLang->getCode()] = true;
                $loaded[$extensionName][$wgContLang->getCode()] = true;
                # Mark that this part has been done to avoid weird if statements.
                $loaded[$extensionName]['*'] = true;
        } elseif( is_string( $langcode ) && !array_key_exists( $langcode, $loaded[$extensionName] ) ) {
                # Load messages for specified language.
                $wgMessageCache->loadMessagesFile( $wgExtensionMessagesFiles[$extensionName], $langcode );
                # Mark that they have been loaded.
                $loaded[$extensionName][$langcode] = true;
        }
}

/**
 * Get a platform-independent path to the null file, e.g.
 * /dev/null
 *
 * @return string
 */
function wfGetNull() {
        return wfIsWindows()
                ? 'NUL'
                : '/dev/null';
}

/**
 * Displays a maxlag error
 *
 * @param string $host Server that lags the most
 * @param int $lag Maxlag (actual)
 * @param int $maxLag Maxlag (requested)
 */
function wfMaxlagError( $host, $lag, $maxLag ) {
        global $wgShowHostnames;
        header( 'HTTP/1.1 503 Service Unavailable' );
        header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
        header( 'X-Database-Lag: ' . intval( $lag ) );
        header( 'Content-Type: text/plain' );
        if( $wgShowHostnames ) {
                echo "Waiting for $host: $lag seconds lagged\n";
        } else {
                echo "Waiting for a database server: $lag seconds lagged\n";
        }
}

/**
 * Throws an E_USER_NOTICE saying that $function is deprecated
 * @param string $function
 * @return null
 */
function wfDeprecated( $function ) {
        global $wgDebugLogFile;
        if ( !$wgDebugLogFile ) {
                return;
        }
        $callers = wfDebugBacktrace();
        if( isset( $callers[2] ) ){
                $callerfunc = $callers[2];
                $callerfile = $callers[1];
                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'] . '::';
                $func .= @$callerfunc['function'];
                $msg = "Use of $function is deprecated. Called from $func in $file";
        } else {
                $msg = "Use of $function is deprecated.";
        }
        wfDebug( "$msg\n" );
}

/**
 * Sleep until the worst slave's replication lag is less than or equal to
 * $maxLag, in seconds.  Use this when updating very large numbers of rows, as
 * in maintenance scripts, to avoid causing too much lag.  Of course, this is
 * a no-op if there are no slaves.
 *
 * Every time the function has to wait for a slave, it will print a message to
 * that effect (and then sleep for a little while), so it's probably not best
 * to use this outside maintenance scripts in its present form.
 *
 * @param int $maxLag
 * @return null
 */
function wfWaitForSlaves( $maxLag ) {
        if( $maxLag ) {
                $lb = wfGetLB();
                list( $host, $lag ) = $lb->getMaxLag();
                while( $lag > $maxLag ) {
                        $name = @gethostbyaddr( $host );
                        if( $name !== false ) {
                                $host = $name;
                        }
                        print "Waiting for $host (lagged $lag seconds)...\n";
                        sleep($maxLag);
                        list( $host, $lag ) = $lb->getMaxLag();
                }
        }
}

/**
 * Output some plain text in command-line mode or in the installer (updaters.inc).
 * Do not use it in any other context, its behaviour is subject to change.
 */
function wfOut( $s ) {
        static $lineStarted = false;
        global $wgCommandLineMode;
        if ( $wgCommandLineMode && !defined( 'MEDIAWIKI_INSTALL' ) ) {
                echo $s;
        } else {
                echo htmlspecialchars( $s );
        }
        flush();
}

/** Generate a random 32-character hexadecimal token.
 * @param mixed $salt Some sort of salt, if necessary, to add to random characters before hashing.
 */
function wfGenerateToken( $salt = '' ) {
        $salt = serialize($salt);

        return md5( mt_rand( 0, 0x7fffffff ) . $salt );
}

/**
 * Replace all invalid characters with -
 * @param mixed $title Filename to process
 */
function wfStripIllegalFilenameChars( $name ) {
        $name = wfBaseName( $name );
        $name = preg_replace ( "/[^".Title::legalChars()."]|:/", '-', $name );
        return $name;
}