Webview Api Prototype (#42690)

* Webview api

* Cleaning up markdown webview

* Hooking up dispose

* Fix some merge errors

* Use custom context key to show markdown title bar contributions

* Add basic on focus and on blur events

* Fixing find widget in webview

* Hookup _isDisposed

* Use new extension resource scheme to load markdown extension resources

* Documenting keep alive

src/vs/workbench/api/node/extHostWebview.ts

@@ -0,0 +1,117 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { MainContext, MainThreadWebviewShape, IMainContext, ExtHostWebviewsShape } from './extHost.protocol';
+import * as vscode from 'vscode';
+import { Emitter } from 'vs/base/common/event';
+import * as typeConverters from 'vs/workbench/api/node/extHostTypeConverters';
+
+class ExtHostWebview implements vscode.Webview {
+	private _title: string;
+	private _html: string;
+	private _options: vscode.WebviewOptions;
+	private _isDisposed: boolean = false;
+
+	public readonly onMessageEmitter = new Emitter<any>();
+	public readonly onMessage = this.onMessageEmitter.event;
+
+	public readonly onBecameActiveEmitter = new Emitter<void>();
+	public readonly onBecameActive = this.onBecameActiveEmitter.event;
+
+	public readonly onBecameInactiveEmitter = new Emitter<void>();
+	public readonly onBecameInactive = this.onBecameInactiveEmitter.event;
+
+	constructor(
+		private readonly _proxy: MainThreadWebviewShape,
+		private readonly _handle: number,
+	) { }
+
+	public dispose() {
+		if (this._isDisposed) {
+			return;
+		}
+		this._isDisposed = true;
+		this._proxy.$disposeWebview(this._handle);
+	}
+
+	get title(): string {
+		return this._title;
+	}
+
+	set title(value: string) {
+		if (this._title !== value) {
+			this._title = value;
+			this._proxy.$setTitle(this._handle, value);
+		}
+	}
+
+	get html(): string {
+		return this._html;
+	}
+
+	set html(value: string) {
+		if (this._html !== value) {
+			this._html = value;
+			this._proxy.$setHtml(this._handle, value);
+		}
+	}
+
+	get options(): vscode.WebviewOptions {
+		return this._options;
+	}
+
+	set options(value: vscode.WebviewOptions) {
+		this._proxy.$setOptions(this._handle, value);
+	}
+
+	public postMessage(message: any): Thenable<any> {
+		return this._proxy.$sendMessage(this._handle, message);
+	}
+}
+
+export class ExtHostWebviews implements ExtHostWebviewsShape {
+	private static _handlePool = 0;
+
+	private readonly _proxy: MainThreadWebviewShape;
+
+	private readonly _webviews = new Map<number, ExtHostWebview>();
+
+	constructor(
+		mainContext: IMainContext
+	) {
+		this._proxy = mainContext.getProxy(MainContext.MainThreadWebview);
+	}
+
+	createWebview(
+		title: string,
+		column: vscode.ViewColumn,
+		options: vscode.WebviewOptions
+	): vscode.Webview {
+		const handle = ExtHostWebviews._handlePool++;
+		this._proxy.$createWebview(handle);
+
+		const webview = new ExtHostWebview(this._proxy, handle);
+		this._webviews.set(handle, webview);
+		webview.title = title;
+		webview.options = options;
+		this._proxy.$show(handle, typeConverters.fromViewColumn(column));
+		return webview;
+	}
+
+	$onMessage(handle: number, message: any): void {
+		const webview = this._webviews.get(handle);
+		webview.onMessageEmitter.fire(message);
+	}
+
+	$onBecameActive(handle: number): void {
+		const webview = this._webviews.get(handle);
+		webview.onBecameActiveEmitter.fire();
+	}
+
+	$onBecameInactive(handle: number): void {
+		const webview = this._webviews.get(handle);
+		webview.onBecameInactiveEmitter.fire();
+	}
+}