102 lines
3.4 KiB
JavaScript
102 lines
3.4 KiB
JavaScript
'use strict';
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const charCodeDefinitions = require('../tokenizer/char-code-definitions.cjs');
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const utils = require('../tokenizer/utils.cjs');
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const REVERSE_SOLIDUS = 0x005c; // U+005C REVERSE SOLIDUS (\)
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function decode(str) {
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const end = str.length - 1;
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let decoded = '';
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for (let i = 0; i < str.length; i++) {
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let code = str.charCodeAt(i);
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if (code === REVERSE_SOLIDUS) {
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// special case at the ending
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if (i === end) {
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// if the next input code point is EOF, do nothing
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break;
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}
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code = str.charCodeAt(++i);
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// consume escaped
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if (charCodeDefinitions.isValidEscape(REVERSE_SOLIDUS, code)) {
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const escapeStart = i - 1;
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const escapeEnd = utils.consumeEscaped(str, escapeStart);
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i = escapeEnd - 1;
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decoded += utils.decodeEscaped(str.substring(escapeStart + 1, escapeEnd));
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} else {
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// \r\n
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if (code === 0x000d && str.charCodeAt(i + 1) === 0x000a) {
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i++;
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}
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}
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} else {
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decoded += str[i];
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}
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}
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return decoded;
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}
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// https://drafts.csswg.org/cssom/#serialize-an-identifier
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// § 2.1. Common Serializing Idioms
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function encode(str) {
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let encoded = '';
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// If the character is the first character and is a "-" (U+002D),
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// and there is no second character, then the escaped character.
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// Note: That's means a single dash string "-" return as escaped dash,
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// so move the condition out of the main loop
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if (str.length === 1 && str.charCodeAt(0) === 0x002D) {
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return '\\-';
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}
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// To serialize an identifier means to create a string represented
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// by the concatenation of, for each character of the identifier:
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for (let i = 0; i < str.length; i++) {
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const code = str.charCodeAt(i);
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// If the character is NULL (U+0000), then the REPLACEMENT CHARACTER (U+FFFD).
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if (code === 0x0000) {
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encoded += '\uFFFD';
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continue;
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}
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if (
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// If the character is in the range [\1-\1f] (U+0001 to U+001F) or is U+007F ...
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// Note: Do not compare with 0x0001 since 0x0000 is precessed before
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code <= 0x001F || code === 0x007F ||
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// [or] ... is in the range [0-9] (U+0030 to U+0039),
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(code >= 0x0030 && code <= 0x0039 && (
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// If the character is the first character ...
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i === 0 ||
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// If the character is the second character ... and the first character is a "-" (U+002D)
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i === 1 && str.charCodeAt(0) === 0x002D
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))
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) {
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// ... then the character escaped as code point.
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encoded += '\\' + code.toString(16) + ' ';
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continue;
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}
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// If the character is not handled by one of the above rules and is greater
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// than or equal to U+0080, is "-" (U+002D) or "_" (U+005F), or is in one
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// of the ranges [0-9] (U+0030 to U+0039), [A-Z] (U+0041 to U+005A),
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// or \[a-z] (U+0061 to U+007A), then the character itself.
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if (charCodeDefinitions.isName(code)) {
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encoded += str.charAt(i);
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} else {
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// Otherwise, the escaped character.
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encoded += '\\' + str.charAt(i);
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}
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}
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return encoded;
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}
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exports.decode = decode;
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exports.encode = encode;
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