Desktop: Resolves #10424: Move the note viewer to a separate process (#10678)

packages/lib/utils/resolvePathWithinDir.test.ts

@@ -0,0 +1,38 @@
+import resolvePathWithinDir from './resolvePathWithinDir';
+
+describe('resolvePathWithinDir', () => {
+	test('should return correct values for Unix-style paths', () => {
+		const testCases = [
+			// Absolute paths
+			{ baseDir: '/a/test/path/', path: '/a/test/path/test.txt', expected: '/a/test/path/test.txt' },
+			{ baseDir: '/a/test/path/', path: '/a/test/path/..test.txt', expected: '/a/test/path/..test.txt' },
+			{ baseDir: '/a/test/path/', path: '/a/test/path/.test.txt', expected: '/a/test/path/.test.txt' },
+			{ baseDir: '/a/test/path', path: '/a/test/path/.test.txt', expected: '/a/test/path/.test.txt' },
+			{ baseDir: '/a/test/path', path: '/a/test/path', expected: '/a/test/path' },
+			{ baseDir: '/a/test/path', path: '/a/', expected: null },
+			{ baseDir: '/a/test/path', path: '/a/test/', expected: null },
+			{ baseDir: '/a/test/path', path: '/a/test/pa', expected: null },
+			{ baseDir: '/a/test/path', path: '/a/test/path2', expected: null },
+			{ baseDir: '/a/test/path', path: '/a/test/path\\//subdir', expected: null },
+
+			// Relative paths
+			{ baseDir: '/a/test/path', path: './test', expected: '/a/test/path/test' },
+			{ baseDir: '/a/test/path', path: '../path/test/2', expected: '/a/test/path/test/2' },
+			{ baseDir: '/a/test/path', path: '../path/test/../../../2', expected: null },
+			{ baseDir: '/a/test/path', path: '../test', expected: null },
+		];
+
+		for (const testCase of testCases) {
+			expect(resolvePathWithinDir(testCase.baseDir, testCase.path, false)).toBe(testCase.expected);
+		}
+	});
+
+	test('should return correct values for Windows-style paths', () => {
+		expect(resolvePathWithinDir('C:\\a\\test\\path', 'C:\\a\\test\\path\\2', true)).toBe('C:\\a\\test\\path\\2');
+		expect(resolvePathWithinDir('C:\\\\a\\test\\path', '.\\path\\2', true)).toBe('C:\\a\\test\\path\\path\\2');
+		expect(resolvePathWithinDir('C:\\a\\test\\path', '..\\path\\2', true)).toBe('C:\\a\\test\\path\\2');
+		expect(resolvePathWithinDir('C:\\a\\test\\path', '..\\2', true)).toBe(null);
+		expect(resolvePathWithinDir('D:\\a\\test\\path', 'C:\\a\\test\\path\\2', true)).toBe(null);
+		expect(resolvePathWithinDir('\\a\\test\\path', 'D:\\a\\test\\path\\2', true)).toBe(null);
+	});
+});

packages/lib/utils/resolvePathWithinDir.ts

@@ -0,0 +1,45 @@
+
+import * as path from 'path';
+
+// Returns `null` if `relativePath` is not within `baseDir` and `relativePath`
+// resolved to an absolute path otherwise.
+//
+// `relativePath` can be either relative or absolute.
+// If relative, it is assumed to be relative to `baseDir`.
+//
+// It is expected that baseDir is a safe path (not user-provided).
+const resolvePathWithinDir = (
+	baseDir: string, relativePath: string,
+
+	// For testing
+	forceWin32Paths?: boolean,
+) => {
+	let pathModule = path;
+	if (forceWin32Paths === true) {
+		pathModule = path.win32;
+	}
+
+	let resolvedBaseDir = pathModule.resolve(baseDir);
+	const resolvedPath = pathModule.resolve(baseDir, relativePath);
+
+	// Handles the case where resolvedBaseDir doesn't end with a
+	// path separator. For example, if
+	//   resolvedBaseDir="/foo/bar"
+	// then we could have
+	//   resolvedPath="/foo/bar2"
+	// which is not within the "/foo/bar" directory.
+	//
+	// We can't do this if the two paths are already equal as (as this would cause
+	// resolvedPath to no longer start with resolvedBaseDir).
+	if (!resolvedBaseDir.endsWith(pathModule.sep) && resolvedBaseDir !== resolvedPath) {
+		resolvedBaseDir += pathModule.sep;
+	}
+
+	if (!resolvedPath.startsWith(resolvedBaseDir)) {
+		return null;
+	}
+
+	return resolvedPath;
+};
+
+export default resolvePathWithinDir;