add fetch file system provider

src/vs/base/common/errors.ts

@@ -194,3 +194,13 @@ export function getErrorMessage(err: any): string {
 
 	return String(err);
 }
+
+
+export class NotImplementedError extends Error {
+	constructor(message?: string) {
+		super('NotImplemented');
+		if (message) {
+			this.message = message;
+		}
+	}
+}

src/vs/workbench/services/extensions/browser/webWorkerFileSystemProvider.ts

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { IFileSystemProvider, FileSystemProviderCapabilities, IStat, FileType, FileDeleteOptions, FileOverwriteOptions, FileWriteOptions, FileSystemProviderError, FileSystemProviderErrorCode } from 'vs/platform/files/common/files';
+
+import { Event } from 'vs/base/common/event';
+import { IDisposable, Disposable } from 'vs/base/common/lifecycle';
+import { URI } from 'vs/base/common/uri';
+import { NotImplementedError } from 'vs/base/common/errors';
+
+export class FetchFileSystemProvider implements IFileSystemProvider {
+
+	readonly capabilities = FileSystemProviderCapabilities.Readonly + FileSystemProviderCapabilities.FileReadWrite + FileSystemProviderCapabilities.PathCaseSensitive;
+	readonly onDidChangeCapabilities = Event.None;
+	readonly onDidChangeFile = Event.None;
+
+	// working implementations
+	async readFile(resource: URI): Promise<Uint8Array> {
+		try {
+			const res = await fetch(resource.toString(true));
+			if (res.status === 200) {
+				return new Uint8Array(await res.arrayBuffer());
+			}
+			throw new FileSystemProviderError(res.statusText, FileSystemProviderErrorCode.Unknown);
+		} catch (err) {
+			throw new FileSystemProviderError(err, FileSystemProviderErrorCode.Unknown);
+		}
+	}
+
+	// fake implementations
+	async stat(_resource: URI): Promise<IStat> {
+		return {
+			type: FileType.File,
+			size: 0,
+			mtime: 0,
+			ctime: 0
+		};
+	}
+
+	watch(): IDisposable {
+		return Disposable.None;
+	}
+
+	// error implementations
+	writeFile(_resource: URI, _content: Uint8Array, _opts: FileWriteOptions): Promise<void> {
+		throw new NotImplementedError();
+	}
+	readdir(_resource: URI): Promise<[string, FileType][]> {
+		throw new NotImplementedError();
+	}
+	mkdir(_resource: URI): Promise<void> {
+		throw new NotImplementedError();
+	}
+	delete(_resource: URI, _opts: FileDeleteOptions): Promise<void> {
+		throw new NotImplementedError();
+	}
+	rename(_from: URI, _to: URI, _opts: FileOverwriteOptions): Promise<void> {
+		throw new NotImplementedError();
+	}
+}