88 lines
2.5 KiB
JavaScript
88 lines
2.5 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Ivan Kopeykin @vankop
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*/
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"use strict";
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/** @typedef {import("./fs").InputFileSystem} InputFileSystem */
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/** @typedef {(error: Error|null, result?: Buffer) => void} ErrorFirstCallback */
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const backSlashCharCode = "\\".charCodeAt(0);
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const slashCharCode = "/".charCodeAt(0);
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const aLowerCaseCharCode = "a".charCodeAt(0);
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const zLowerCaseCharCode = "z".charCodeAt(0);
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const aUpperCaseCharCode = "A".charCodeAt(0);
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const zUpperCaseCharCode = "Z".charCodeAt(0);
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const _0CharCode = "0".charCodeAt(0);
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const _9CharCode = "9".charCodeAt(0);
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const plusCharCode = "+".charCodeAt(0);
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const hyphenCharCode = "-".charCodeAt(0);
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const colonCharCode = ":".charCodeAt(0);
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const hashCharCode = "#".charCodeAt(0);
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const queryCharCode = "?".charCodeAt(0);
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/**
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* Get scheme if specifier is an absolute URL specifier
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* e.g. Absolute specifiers like 'file:///user/webpack/index.js'
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* https://tools.ietf.org/html/rfc3986#section-3.1
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* @param {string} specifier specifier
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* @returns {string|undefined} scheme if absolute URL specifier provided
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*/
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function getScheme(specifier) {
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const start = specifier.charCodeAt(0);
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// First char maybe only a letter
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if (
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(start < aLowerCaseCharCode || start > zLowerCaseCharCode) &&
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(start < aUpperCaseCharCode || start > zUpperCaseCharCode)
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) {
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return undefined;
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}
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let i = 1;
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let ch = specifier.charCodeAt(i);
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while (
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(ch >= aLowerCaseCharCode && ch <= zLowerCaseCharCode) ||
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(ch >= aUpperCaseCharCode && ch <= zUpperCaseCharCode) ||
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(ch >= _0CharCode && ch <= _9CharCode) ||
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ch === plusCharCode ||
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ch === hyphenCharCode
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) {
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if (++i === specifier.length) return undefined;
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ch = specifier.charCodeAt(i);
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}
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// Scheme must end with colon
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if (ch !== colonCharCode) return undefined;
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// Check for Windows absolute path
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// https://url.spec.whatwg.org/#url-miscellaneous
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if (i === 1) {
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const nextChar = i + 1 < specifier.length ? specifier.charCodeAt(i + 1) : 0;
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if (
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nextChar === 0 ||
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nextChar === backSlashCharCode ||
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nextChar === slashCharCode ||
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nextChar === hashCharCode ||
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nextChar === queryCharCode
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) {
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return undefined;
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}
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}
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return specifier.slice(0, i).toLowerCase();
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}
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/**
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* @param {string} specifier specifier
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* @returns {string | null | undefined} protocol if absolute URL specifier provided
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*/
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function getProtocol(specifier) {
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const scheme = getScheme(specifier);
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return scheme === undefined ? undefined : scheme + ":";
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}
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exports.getScheme = getScheme;
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exports.getProtocol = getProtocol;
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