improve windows absolute path detection

lib/util/URLAbsoluteSpecifier.js

@@ -11,6 +11,7 @@ const { getMimetype: getDataUrlMimetype } = require("./DataURI");
 /** @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);
@@ -20,6 +21,8 @@ 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'
@@ -34,8 +37,9 @@ function getScheme(specifier) {
 	if (
 		(start < aLowerCaseCharCode || start > zLowerCaseCharCode) &&
 		(start < aUpperCaseCharCode || start > zUpperCaseCharCode)
-	)
+	) {
 		return undefined;
+	}
 
 	let i = 1;
 	let ch = specifier.charCodeAt(i);
@@ -53,8 +57,21 @@ function getScheme(specifier) {
 
 	// Scheme must end with colon
 	if (ch !== colonCharCode) return undefined;
+
 	// Check for Windows absolute path
-	if (specifier.charCodeAt(i + 1) === backSlashCharCode) return undefined;
+	// 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();
 }
@@ -64,7 +81,8 @@ function getScheme(specifier) {
  * @returns {string|null} protocol if absolute URL specifier provided
  */
 function getProtocol(specifier) {
-	return getScheme(specifier) + ":";
+	const scheme = getScheme(specifier);
+	return scheme === undefined ? undefined : scheme + ":";
 }
 
 /**

test/URLAbsoluteSpecifier.unittest.js

@@ -47,12 +47,28 @@ const samples = [
 	{
 		specifier: "D:\\path\\file.js",
 		expected: undefined
+	},
+	{
+		specifier: "d:/path/file.js",
+		expected: undefined
+	},
+	{
+		specifier: "z:#foo",
+		expected: undefined
+	},
+	{
+		specifier: "Z:?query",
+		expected: undefined
+	},
+	{
+		specifier: "C:",
+		expected: undefined
 	}
 ];
 
 describe("getScheme", () => {
 	samples.forEach(({ specifier, expected }, i) => {
-		it(`sample #${i + 1}`, () => {
+		it(`should handle ${specifier}`, () => {
 			expect(getScheme(specifier)).toBe(expected);
 		});
 	});
@@ -60,8 +76,10 @@ describe("getScheme", () => {
 
 describe("getProtocol", () => {
 	samples.forEach(({ specifier, expected }, i) => {
-		it(`sample #${i + 1}`, () => {
-			expect(getProtocol(specifier)).toBe(expected + ":");
+		it(`should handle ${specifier}`, () => {
+			expect(getProtocol(specifier)).toBe(
+				expected ? expected + ":" : undefined
+			);
 		});
 	});
 });