HttpDate.php

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<?php
 
namespace MediaWiki\Rest\HeaderParser;
 
class HttpDate extends HeaderParserBase {
    private static $dayNames = [
        'Mon' => true,
        'Tue' => true,
        'Wed' => true,
        'Thu' => true,
        'Fri' => true,
        'Sat' => true,
        'Sun' => true
    ];
 
    private static $monthsByName = [
        'Jan' => 1,
        'Feb' => 2,
        'Mar' => 3,
        'Apr' => 4,
        'May' => 5,
        'Jun' => 6,
        'Jul' => 7,
        'Aug' => 8,
        'Sep' => 9,
        'Oct' => 10,
        'Nov' => 11,
        'Dec' => 12,
    ];
 
    private static $dayNamesLong = [
        'Monday',
        'Tuesday',
        'Wednesday',
        'Thursday',
        'Friday',
        'Saturday',
        'Sunday',
    ];
 
    private $dayName;
    private $day;
    private $month;
    private $year;
    private $hour;
    private $minute;
    private $second;
 
    public static function parse( $dateString ) {
        $parser = new self( $dateString );
        if ( $parser->execute() ) {
            return $parser->getUnixTime();
        } else {
            return null;
        }
    }
 
    public static function format( $unixTime ) {
        return gmdate( 'D, d M Y H:i:s \G\M\T', $unixTime );
    }
 
    private function __construct( $input ) {
        $this->setInput( $input );
    }
 
    private function execute() {
        $this->pos = 0;
        try {
            $this->consumeFixdate();
            $this->assertEnd();
            return true;
        } catch ( HeaderParserError $e ) {
        }
        $this->pos = 0;
        try {
            $this->consumeRfc850Date();
            $this->assertEnd();
            return true;
        } catch ( HeaderParserError $e ) {
        }
        $this->pos = 0;
        try {
            $this->consumeAsctimeDate();
            $this->assertEnd();
            return true;
        } catch ( HeaderParserError $e ) {
        }
        return false;
    }
 
    private function consumeFixdate() {
        $this->consumeDayName();
        $this->consumeString( ', ' );
        $this->consumeDate1();
        $this->consumeString( ' ' );
        $this->consumeTimeOfDay();
        $this->consumeString( ' GMT' );
    }
 
    private function consumeDayName() {
        $next3 = substr( $this->input, $this->pos, 3 );
        if ( isset( self::$dayNames[$next3] ) ) {
            $this->dayName = $next3;
            $this->pos += 3;
        } else {
            $this->error( 'expected day-name' );
        }
    }
 
    private function consumeDate1() {
        $this->consumeDay();
        $this->consumeString( ' ' );
        $this->consumeMonth();
        $this->consumeString( ' ' );
        $this->consumeYear();
    }
 
    private function consumeDay() {
        $this->day = $this->consumeFixedDigits( 2 );
    }
 
    private function consumeMonth() {
        $next3 = substr( $this->input, $this->pos, 3 );
        if ( isset( self::$monthsByName[$next3] ) ) {
            $this->month = self::$monthsByName[$next3];
            $this->pos += 3;
        } else {
            $this->error( 'expected month' );
        }
    }
 
    private function consumeYear() {
        $this->year = (int)$this->consumeFixedDigits( 4 );
    }
 
    private function consumeTimeOfDay() {
        $this->hour = $this->consumeFixedDigits( 2 );
        $this->consumeString( ':' );
        $this->minute = $this->consumeFixedDigits( 2 );
        $this->consumeString( ':' );
        $this->second = $this->consumeFixedDigits( 2 );
    }
 
    private function consumeRfc850Date() {
        $this->consumeDayNameLong();
        $this->consumeString( ', ' );
        $this->consumeDate2();
        $this->consumeString( ' ' );
        $this->consumeTimeOfDay();
        $this->consumeString( ' GMT' );
    }
 
    private function consumeDate2() {
        $this->consumeDay();
        $this->consumeString( '-' );
        $this->consumeMonth();
        $this->consumeString( '-' );
        $year = $this->consumeFixedDigits( 2 );
        // RFC 2626 section 11.2
        $currentYear = (int)gmdate( 'Y' );
        $startOfCentury = (int)round( $currentYear, -2 );
        $this->year = $startOfCentury + intval( $year );
        $pivot = $currentYear + 50;
        if ( $this->year > $pivot ) {
            $this->year -= 100;
        }
    }
 
    private function consumeDayNameLong() {
        foreach ( self::$dayNamesLong as $dayName ) {
            if ( substr_compare( $this->input, $dayName, $this->pos, strlen( $dayName ) ) === 0 ) {
                $this->dayName = substr( $dayName, 0, 3 );
                $this->pos += strlen( $dayName );
                return;
            }
        }
        $this->error( 'expected day-name-l' );
    }
 
    private function consumeAsctimeDate() {
        $this->consumeDayName();
        $this->consumeString( ' ' );
        $this->consumeDate3();
        $this->consumeString( ' ' );
        $this->consumeTimeOfDay();
        $this->consumeString( ' ' );
        $this->consumeYear();
    }
 
    private function consumeDate3() {
        $this->consumeMonth();
        $this->consumeString( ' ' );
        if ( ( $this->input[$this->pos] ?? '' ) === ' ' ) {
            $this->pos++;
            $this->day = '0' . $this->consumeFixedDigits( 1 );
        } else {
            $this->day = $this->consumeFixedDigits( 2 );
        }
    }
 
    private function getUnixTime() {
        return gmmktime( (int)$this->hour, (int)$this->minute, (int)$this->second,
            $this->month, (int)$this->day, $this->year );
    }
}