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    public 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 const 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 const 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[ \- ? | < > = ! % @ ` \p{Zs}]/xu', $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