Merge from vscode 8e0f348413f4f616c23a88ae30030efa85811973 (#6381)

* Merge from vscode 8e0f348413f4f616c23a88ae30030efa85811973

* disable strict null check

extensions/markdown-language-features/src/util/resources.ts

@@ -0,0 +1,33 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as vscode from 'vscode';
+
+export interface WebviewResourceProvider {
+	toWebviewResource(resource: vscode.Uri): vscode.Uri;
+
+	readonly cspSource: string;
+}
+
+export function normalizeResource(
+	base: vscode.Uri,
+	resource: vscode.Uri
+): vscode.Uri {
+	// If we  have a windows path and are loading a workspace with an authority,
+	// make sure we use a unc path with an explicit localhost authority.
+	//
+	// Otherwise, the `<base>` rule will insert the authority into the resolved resource
+	// URI incorrectly.
+	if (base.authority && !resource.authority) {
+		const driveMatch = resource.path.match(/^\/(\w):\//);
+		if (driveMatch) {
+			return vscode.Uri.file(`\\\\localhost\\${driveMatch[1]}$\\${resource.fsPath.replace(/^\w:\\/, '')}`).with({
+				fragment: resource.fragment,
+				query: resource.query
+			});
+		}
+	}
+	return resource;
+}