webpack/lib/util/URLAbsoluteSpecifier.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Ivan Kopeykin @vankop
*/

"use strict";

/** @typedef {import("./fs").InputFileSystem} InputFileSystem */
/** @typedef {(error: Error|null, result?: Buffer) => void} ErrorFirstCallback */

const backSlashCharCode = "\\".charCodeAt(0);
const slashCharCode = "/".charCodeAt(0);
const aLowerCaseCharCode = "a".charCodeAt(0);
const zLowerCaseCharCode = "z".charCodeAt(0);
const aUpperCaseCharCode = "A".charCodeAt(0);
const zUpperCaseCharCode = "Z".charCodeAt(0);
const _0CharCode = "0".charCodeAt(0);
const _9CharCode = "9".charCodeAt(0);
const plusCharCode = "+".charCodeAt(0);
const hyphenCharCode = "-".charCodeAt(0);
const colonCharCode = ":".charCodeAt(0);
const hashCharCode = "#".charCodeAt(0);
const queryCharCode = "?".charCodeAt(0);
/**
 * Get scheme if specifier is an absolute URL specifier
 * e.g. Absolute specifiers like 'file:///user/webpack/index.js'
 * https://tools.ietf.org/html/rfc3986#section-3.1
 * @param {string} specifier specifier
 * @returns {string|undefined} scheme if absolute URL specifier provided
 */
function getScheme(specifier) {
	const start = specifier.charCodeAt(0);

	// First char maybe only a letter
	if (
		(start < aLowerCaseCharCode || start > zLowerCaseCharCode) &&
		(start < aUpperCaseCharCode || start > zUpperCaseCharCode)
	) {
		return undefined;
	}

	let i = 1;
	let ch = specifier.charCodeAt(i);

	while (
		(ch >= aLowerCaseCharCode && ch <= zLowerCaseCharCode) ||
		(ch >= aUpperCaseCharCode && ch <= zUpperCaseCharCode) ||
		(ch >= _0CharCode && ch <= _9CharCode) ||
		ch === plusCharCode ||
		ch === hyphenCharCode
	) {
		if (++i === specifier.length) return undefined;
		ch = specifier.charCodeAt(i);
	}

	// Scheme must end with colon
	if (ch !== colonCharCode) return undefined;

	// Check for Windows absolute path
	// https://url.spec.whatwg.org/#url-miscellaneous
	if (i === 1) {
		const nextChar = i + 1 < specifier.length ? specifier.charCodeAt(i + 1) : 0;
		if (
			nextChar === 0 ||
			nextChar === backSlashCharCode ||
			nextChar === slashCharCode ||
			nextChar === hashCharCode ||
			nextChar === queryCharCode
		) {
			return undefined;
		}
	}

	return specifier.slice(0, i).toLowerCase();
}

/**
 * @param {string} specifier specifier
 * @returns {string|null} protocol if absolute URL specifier provided
 */
function getProtocol(specifier) {
	const scheme = getScheme(specifier);
	return scheme === undefined ? undefined : scheme + ":";
}

exports.getScheme = getScheme;
exports.getProtocol = getProtocol;