100 lines
3.1 KiB
JavaScript
100 lines
3.1 KiB
JavaScript
import {
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isHexDigit,
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isWhiteSpace,
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isValidEscape,
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consumeEscaped,
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decodeEscaped
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} from '../tokenizer/index.js';
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const REVERSE_SOLIDUS = 0x005c; // U+005C REVERSE SOLIDUS (\)
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const QUOTATION_MARK = 0x0022; // "
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const APOSTROPHE = 0x0027; // '
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export function decode(str) {
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const len = str.length;
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const firstChar = str.charCodeAt(0);
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const start = firstChar === QUOTATION_MARK || firstChar === APOSTROPHE ? 1 : 0;
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const end = start === 1 && len > 1 && str.charCodeAt(len - 1) === firstChar ? len - 2 : len - 1;
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let decoded = '';
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for (let i = start; i <= end; 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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// otherwise include last quote as escaped
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if (i !== len - 1) {
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decoded = str.substr(i + 1);
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}
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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 (isValidEscape(REVERSE_SOLIDUS, code)) {
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const escapeStart = i - 1;
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const escapeEnd = consumeEscaped(str, escapeStart);
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i = escapeEnd - 1;
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decoded += 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-a-string
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// § 2.1. Common Serializing Idioms
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export function encode(str, apostrophe) {
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const quote = apostrophe ? '\'' : '"';
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const quoteCode = apostrophe ? APOSTROPHE : QUOTATION_MARK;
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let encoded = '';
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let wsBeforeHexIsNeeded = false;
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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 the character is in the range [\1-\1f] (U+0001 to U+001F) or is U+007F,
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// the character escaped as code point.
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// Note: Do not compare with 0x0001 since 0x0000 is precessed before
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if (code <= 0x001f || code === 0x007F) {
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encoded += '\\' + code.toString(16);
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wsBeforeHexIsNeeded = true;
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continue;
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}
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// If the character is '"' (U+0022) or "\" (U+005C), the escaped character.
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if (code === quoteCode || code === REVERSE_SOLIDUS) {
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encoded += '\\' + str.charAt(i);
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wsBeforeHexIsNeeded = false;
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} else {
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if (wsBeforeHexIsNeeded && (isHexDigit(code) || isWhiteSpace(code))) {
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encoded += ' ';
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}
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// Otherwise, the character itself.
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encoded += str.charAt(i);
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wsBeforeHexIsNeeded = false;
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}
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}
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return quote + encoded + quote;
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}
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