Smarter activation / deactivation of server polling (#7)

src/controllers/ExtensionController.ts

@@ -57,6 +57,7 @@ export class ExtensionController implements Disposable {
     this.initializeConnectionController();
     this.initializeCommands();
     this.initializeWebViews();
+    this.initializePolling();
 
     logger.info(
       'Congratulations, your extension "vscode-deephaven" is now active!'
@@ -296,6 +297,21 @@ export class ExtensionController implements Disposable {
     );
   };
 
+  /**
+   * Listen to events that will enable / disable server polling.
+   */
+  initializePolling = (): void => {
+    assertDefined(this._serverTreeView, 'serverManager');
+
+    vscode.window.onDidChangeWindowState(
+      this.onUpdateServerPolling,
+      undefined,
+      this._context.subscriptions
+    );
+
+    this._serverTreeView.onDidChangeVisibility(this.onUpdateServerPolling);
+  };
+
   /**
    * Handle connecting to a server
    */
@@ -374,6 +390,21 @@ export class ExtensionController implements Disposable {
     await dhService?.runEditorCode(editor, true);
   };
 
+  /**
+   * Enable / disable server polling based on whether server tree view is visible
+   * and vscode window is active and focused.
+   */
+  onUpdateServerPolling = (): void => {
+    // Only poll servers if vscode window is active and focused and server
+    // connection tree is visible
+    const enablePolling =
+      this._serverTreeView?.visible &&
+      vscode.window.state.active &&
+      vscode.window.state.focused;
+
+    this._serverManager?.setPolling(enablePolling ?? false);
+  };
+
   /**
    * Register a command and add it's subscription to the context.
    */

src/services/ServerManager.ts

@@ -55,6 +55,24 @@ export class ServerManager implements IServerManager {
     this.loadServerConfig();
   }
 
+  /**
+   * Enable / disable polling configured servers.
+   * @param enablePolling
+   */
+  setPolling = (enablePolling: boolean): void => {
+    if (enablePolling) {
+      if (!this._poller.isRunning) {
+        logger.debug('Start polling servers.');
+        this._poller.start(this.updateStatus, SERVER_STATUS_CHECK_INTERVAL);
+      }
+    } else {
+      if (this._poller.isRunning) {
+        logger.debug('Stop polling servers.');
+        this._poller.stop();
+      }
+    }
+  };
+
   ensureHasPolledServers = async (): Promise<void> => {
     if (this._hasPolledServers) {
       return;
@@ -88,6 +106,8 @@ export class ServerManager implements IServerManager {
         this.disconnectFromServer(serverUrl);
       }
     }
+
+    this.updateStatus();
   };
 
   connectToServer = async (serverUrl: URL): Promise<IDhService | null> => {
@@ -174,12 +194,6 @@ export class ServerManager implements IServerManager {
     isRunning?: boolean;
     hasConnections?: boolean;
   } = {}): ServerState[] => {
-    // Start polling server status the first time servers are requested.
-    // TBD: Is there a way to stop this when the servers list goes out of view?
-    if (!this._poller.isRunning) {
-      this._poller.start(this.updateStatus, SERVER_STATUS_CHECK_INTERVAL);
-    }
-
     const servers = [...this._serverMap.values()];
 
     const match = (server: ServerState): boolean =>

src/types/serviceTypes.d.ts

@@ -64,6 +64,8 @@ export type IDhServiceFactory = IFactory<IDhService, [serverUrl: URL]>;
  */
 export interface IServerManager extends Disposable {
   ensureHasPolledServers: () => Promise<void>;
+  setPolling: (isPolling: boolean) => void;
+
   connectToServer: (serverUrl: URL) => Promise<IDhService | null>;
   disconnectEditor: (uri: vscode.Uri) => void;
   disconnectFromServer: (serverUrl: URL) => Promise<void>;