[html] split extension (for #45900)

extensions/html-language-features/server/src/utils/documentContext.ts

@@ -0,0 +1,40 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { DocumentContext } from 'vscode-html-languageservice';
+import { endsWith, startsWith } from '../utils/strings';
+import * as url from 'url';
+import { WorkspaceFolder } from 'vscode-languageserver';
+
+export function getDocumentContext(documentUri: string, workspaceFolders: WorkspaceFolder[]): DocumentContext {
+	function getRootFolder(): string | undefined {
+		for (let folder of workspaceFolders) {
+			let folderURI = folder.uri;
+			if (!endsWith(folderURI, '/')) {
+				folderURI = folderURI + '/';
+			}
+			if (startsWith(documentUri, folderURI)) {
+				return folderURI;
+			}
+		}
+		return void 0;
+	}
+
+	return {
+		resolveReference: (ref, base = documentUri) => {
+			if (ref[0] === '/') { // resolve absolute path against the current workspace folder
+				if (startsWith(base, 'file://')) {
+					let folderUri = getRootFolder();
+					if (folderUri) {
+						return folderUri + ref.substr(1);
+					}
+				}
+			}
+			return url.resolve(base, ref);
+		},
+	};
+}
+