Deserialize overview in new session (#114)

* Deserialize overview in new session

* Auto dispose new disposable

* use ExtensionContext.asAbsolutePath

* Add more disposables to context.subscriptions

Author: akaroml

package.json

@@ -36,7 +36,8 @@
     "workspaceContains:build.gradle",
     "workspaceContains:mnvw",
     "onCommand:java.overview",
-    "onCommand:java.showLatestReleaseNotes"
+    "onCommand:java.showLatestReleaseNotes",
+    "onWebviewPanel:java.overview"
   ],
   "contributes": {
     "commands": [

src/extension.ts

@@ -8,7 +8,7 @@ import { initialize as initUtils } from "./utils";
 import { initialize as initCommands } from "./commands";
 import { initialize as initRecommendations } from "./recommendation";
 import { initialize as initMisc, showReleaseNotesOnStart } from "./misc";
-import { showOverviewPageOnActivation } from './overview';
+import { showOverviewPageOnActivation, OverviewViewSerializer } from './overview';
 
 export async function activate(context: vscode.ExtensionContext) {
   initializeTelemetry(context);
@@ -21,6 +21,8 @@ async function initializeExtension(operationId: string, context: vscode.Extensio
   initRecommendations(context);
   initMisc(context);
 
+  context.subscriptions.push(vscode.window.registerWebviewPanelSerializer('java.overview', new OverviewViewSerializer()));
+
   await showOverviewPageOnActivation(context);
   await showReleaseNotesOnStart(context);
 }

src/overview/index.ts

@@ -10,6 +10,7 @@ import * as path from 'path';
 const readFile = util.promisify(fsReadFile);
 
 import { instrumentOperation, sendInfo } from "vscode-extension-telemetry-wrapper";
+import { getExtensionContext } from "../utils";
 
 let overviewView: vscode.WebviewPanel | undefined;
 const KEY_SHOW_WHEN_USING_JAVA = 'showWhenUsingJava';
@@ -45,30 +46,40 @@ export async function overviewCmdHandler(context: vscode.ExtensionContext, opera
 
   context.globalState.update(KEY_OVERVIEW_LAST_SHOW_TIME, Date.now().toString());
 
-  overviewView.iconPath = vscode.Uri.file(path.join(context.extensionPath, 'logo.lowres.png'));
-  let buffer = await readFile(path.join(context.extensionPath, './out/assets/overview/index.html'));
-  overviewView.webview.html = buffer.toString();
+  await initializeOverviewView(context, overviewView, onDidDisposeWebviewPanel);
+}
 
-  overviewView.onDidDispose(() => {
-    overviewView = undefined;
-  });
+function onDidDisposeWebviewPanel() {
+  overviewView = undefined;
+}
+
+async function initializeOverviewView(context: vscode.ExtensionContext, webviewPanel: vscode.WebviewPanel, onDisposeCallback: () => void) {
+  webviewPanel.iconPath = vscode.Uri.file(path.join(context.extensionPath, 'logo.lowres.png'));
+  webviewPanel.webview.html = await loadHtmlContent(context);
+
+  context.subscriptions.push(webviewPanel.onDidDispose(onDisposeCallback));
 
   const installedExtensions = vscode.extensions.all.map(ext => ext.id.toLowerCase());
-  overviewView.webview.postMessage({
+  webviewPanel.webview.postMessage({
     command: 'hideInstalledExtensions',
     installedExtensions: installedExtensions
   });
 
-  overviewView.webview.postMessage({
+  webviewPanel.webview.postMessage({
     command: 'setOverviewVisibility',
     visibility: context.globalState.get(KEY_SHOW_WHEN_USING_JAVA)
   });
 
-  overviewView.webview.onDidReceiveMessage((e) => {
+  context.subscriptions.push(webviewPanel.webview.onDidReceiveMessage((e) => {
     if (e.command === 'setOverviewVisibility') {
       toggleOverviewVisibilityOperation(context, e.visibility);
     }
-  });
+  }));
+}
+
+async function loadHtmlContent(context: vscode.ExtensionContext) {
+  let buffer = await readFile(context.asAbsolutePath('./out/assets/overview/index.html'));
+  return buffer.toString();
 }
 
 export async function showOverviewPageOnActivation(context: vscode.ExtensionContext) {
@@ -83,3 +94,16 @@ export async function showOverviewPageOnActivation(context: vscode.ExtensionCont
     vscode.commands.executeCommand('java.overview', showInBackground);
   }
 }
+
+export class OverviewViewSerializer implements vscode.WebviewPanelSerializer {
+  async deserializeWebviewPanel(webviewPanel: vscode.WebviewPanel, state: any) {
+    if (overviewView) {
+      overviewView.reveal();
+      webviewPanel.dispose();
+      return;
+    }
+
+    overviewView = webviewPanel;
+    initializeOverviewView(getExtensionContext(), webviewPanel, onDidDisposeWebviewPanel);
+  }
+}