1<?php
  2
  3/*
  4 * This file is part of the Symfony package.
  5 *
  6 * (c) Fabien Potencier <fabien@symfony.com>
  7 *
  8 * For the full copyright and license information, please view the LICENSE
  9 * file that was distributed with this source code.
 10 */
 11
 12namespace Symfony\Component\Yaml;
 13
 14/**
 15 * Escaper encapsulates escaping rules for single and double-quoted
 16 * YAML strings.
 17 *
 18 * @author Matthew Lewinski <matthew@lewinski.org>
 19 *
 20 * @internal
 21 */
 22class Escaper
 23{
 24    // Characters that would cause a dumped string to require double quoting.
 25    const REGEX_CHARACTER_TO_ESCAPE = "[\\x00-\\x1f]|\x7f|\xc2\x85|\xc2\xa0|\xe2\x80\xa8|\xe2\x80\xa9";
 26
 27    // Mapping arrays for escaping a double quoted string. The backslash is
 28    // first to ensure proper escaping because str_replace operates iteratively
 29    // on the input arrays. This ordering of the characters avoids the use of strtr,
 30    // which performs more slowly.
 31    private static $escapees = ['\\', '\\\\', '\\"', '"',
 32                                     "\x00",  "\x01",  "\x02",  "\x03",  "\x04",  "\x05",  "\x06",  "\x07",
 33                                     "\x08",  "\x09",  "\x0a",  "\x0b",  "\x0c",  "\x0d",  "\x0e",  "\x0f",
 34                                     "\x10",  "\x11",  "\x12",  "\x13",  "\x14",  "\x15",  "\x16",  "\x17",
 35                                     "\x18",  "\x19",  "\x1a",  "\x1b",  "\x1c",  "\x1d",  "\x1e",  "\x1f",
 36                                     "\x7f",
 37                                     "\xc2\x85", "\xc2\xa0", "\xe2\x80\xa8", "\xe2\x80\xa9",
 38                               ];
 39    private static $escaped = ['\\\\', '\\"', '\\\\', '\\"',
 40                                     '\\0',   '\\x01', '\\x02', '\\x03', '\\x04', '\\x05', '\\x06', '\\a',
 41                                     '\\b',   '\\t',   '\\n',   '\\v',   '\\f',   '\\r',   '\\x0e', '\\x0f',
 42                                     '\\x10', '\\x11', '\\x12', '\\x13', '\\x14', '\\x15', '\\x16', '\\x17',
 43                                     '\\x18', '\\x19', '\\x1a', '\\e',   '\\x1c', '\\x1d', '\\x1e', '\\x1f',
 44                                     '\\x7f',
 45                                     '\\N', '\\_', '\\L', '\\P',
 46                              ];
 47
 48    /**
 49     * Determines if a PHP value would require double quoting in YAML.
 50     *
 51     * @param string $value A PHP value
 52     *
 53     * @return bool True if the value would require double quotes
 54     */
 55    public static function requiresDoubleQuoting(string $value): bool
 56    {
 57        return 0 < preg_match('/'.self::REGEX_CHARACTER_TO_ESCAPE.'/u', $value);
 58    }
 59
 60    /**
 61     * Escapes and surrounds a PHP value with double quotes.
 62     *
 63     * @param string $value A PHP value
 64     *
 65     * @return string The quoted, escaped string
 66     */
 67    public static function escapeWithDoubleQuotes(string $value): string
 68    {
 69        return sprintf('"%s"', str_replace(self::$escapees, self::$escaped, $value));
 70    }
 71
 72    /**
 73     * Determines if a PHP value would require single quoting in YAML.
 74     *
 75     * @param string $value A PHP value
 76     *
 77     * @return bool True if the value would require single quotes
 78     */
 79    public static function requiresSingleQuoting(string $value): bool
 80    {
 81        // Determines if a PHP value is entirely composed of a value that would
 82        // require single quoting in YAML.
 83        if (\in_array(strtolower($value), ['null', '~', 'true', 'false', 'y', 'n', 'yes', 'no', 'on', 'off'])) {
 84            return true;
 85        }
 86
 87        // Determines if the PHP value contains any single characters that would
 88        // cause it to require single quoting in YAML.
 89        return 0 < preg_match('/[ \s \' " \: \{ \} \[ \] , & \* \# \?] | \A[ \- ? | < > = ! % @ ` ]/x', $value);
 90    }
 91
 92    /**
 93     * Escapes and surrounds a PHP value with single quotes.
 94     *
 95     * @param string $value A PHP value
 96     *
 97     * @return string The quoted, escaped string
 98     */
 99    public static function escapeWithSingleQuotes(string $value): string
100    {
101        return sprintf("'%s'", str_replace('\'', '\'\'', $value));
102    }
103}
104