Merge pull request #6305 from ian-r-rose/filebrowser-poll

Use new Poll class for filebrowser contents polling.

packages/coreutils/src/poll.ts

@@ -309,6 +309,11 @@ export class Poll<T = any, U = any> implements IDisposable, IPoll<T, U> {
    * Refreshes the poll. Schedules `refreshed` tick if necessary.
    *
    * @returns A promise that resolves after tick is scheduled and never rejects.
+   *
+   * #### Notes
+   * The returned promise resolves after the tick is scheduled, but before
+   * the polling action is run. To wait until after the poll action executes,
+   * await the `poll.tick` promise: `await poll.refresh(); await poll.tick;`
    */
   refresh(): Promise<void> {
     return this.schedule({

packages/filebrowser/src/model.ts

@@ -5,7 +5,8 @@ import {
   IChangedArgs,
   IStateDB,
   PathExt,
-  PageConfig
+  PageConfig,
+  Poll
 } from '@jupyterlab/coreutils';
 
 import { IDocumentManager, shouldOverwrite } from '@jupyterlab/docmanager';
@@ -34,11 +35,6 @@ import { showDialog, Dialog } from '@jupyterlab/apputils';
  */
 const DEFAULT_REFRESH_INTERVAL = 10000;
 
-/**
- * The enforced time between refreshes in ms.
- */
-const MIN_REFRESH = 1000;
-
 /**
  * The maximum upload size (in bytes) for notebook version < 5.1.0
  */
@@ -87,8 +83,7 @@ export class FileBrowserModel implements IDisposable {
       format: 'text'
     };
     this._state = options.state || null;
-    this._baseRefreshDuration =
-      options.refreshInterval || DEFAULT_REFRESH_INTERVAL;
+    const refreshInterval = options.refreshInterval || DEFAULT_REFRESH_INTERVAL;
 
     const { services } = options.manager;
     services.contents.fileChanged.connect(this._onFileChanged, this);
@@ -103,8 +98,15 @@ export class FileBrowserModel implements IDisposable {
       }
     };
     window.addEventListener('beforeunload', this._unloadEventListener);
-    this._scheduleUpdate();
-    this._startTimer();
+    this._poll = new Poll({
+      factory: () => this.cd('.'),
+      frequency: {
+        interval: refreshInterval,
+        backoff: true,
+        max: 300 * 1000
+      },
+      standby: 'when-hidden'
+    });
   }
 
   /**
@@ -198,7 +200,7 @@ export class FileBrowserModel implements IDisposable {
     }
     window.removeEventListener('beforeunload', this._unloadEventListener);
     this._isDisposed = true;
-    clearTimeout(this._timeoutId);
+    this._poll.dispose();
     this._sessions.length = 0;
     this._items.length = 0;
     Signal.clearData(this);
@@ -225,10 +227,9 @@ export class FileBrowserModel implements IDisposable {
   /**
    * Force a refresh of the directory contents.
    */
-  refresh(): Promise<void> {
-    this._lastRefresh = new Date().getTime();
-    this._requested = false;
-    return this.cd('.');
+  async refresh(): Promise<void> {
+    await this._poll.refresh();
+    await this._poll.tick;
   }
 
   /**
@@ -269,9 +270,9 @@ export class FileBrowserModel implements IDisposable {
         if (this.isDisposed) {
           return;
         }
-        this._refreshDuration = this._baseRefreshDuration;
         this._handleContents(contents);
         this._pendingPath = null;
+        this._pending = null;
         if (oldValue !== newValue) {
           // If there is a state database and a unique key, save the new path.
           // We don't need to wait on the save to continue.
@@ -296,7 +297,6 @@ export class FileBrowserModel implements IDisposable {
           this._connectionFailure.emit(error);
           return this.cd('/');
         } else {
-          this._refreshDuration = this._baseRefreshDuration * 10;
           this._connectionFailure.emit(error);
         }
       });
@@ -586,7 +586,7 @@ export class FileBrowserModel implements IDisposable {
 
     // If either the old value or the new value is in the current path, update.
     if (value) {
-      this._scheduleUpdate();
+      void this._poll.refresh();
       this._populateSessions(sessions.running());
       this._fileChanged.emit(change);
       return;
@@ -605,38 +605,6 @@ export class FileBrowserModel implements IDisposable {
     });
   }
 
-  /**
-   * Start the internal refresh timer.
-   */
-  private _startTimer(): void {
-    this._timeoutId = window.setInterval(() => {
-      if (this._requested) {
-        void this.refresh();
-        return;
-      }
-      if (document.hidden) {
-        // Don't poll when nobody's looking.
-        return;
-      }
-      let date = new Date().getTime();
-      if (date - this._lastRefresh > this._refreshDuration) {
-        void this.refresh();
-      }
-    }, MIN_REFRESH);
-  }
-
-  /**
-   * Handle internal model refresh logic.
-   */
-  private _scheduleUpdate(): void {
-    let date = new Date().getTime();
-    if (date - this._lastRefresh > MIN_REFRESH) {
-      void this.refresh();
-    } else {
-      this._requested = true;
-    }
-  }
-
   private _connectionFailure = new Signal<this, Error>(this);
   private _fileChanged = new Signal<this, Contents.IChangedArgs>(this);
   private _items: Contents.IModel[] = [];
@@ -647,19 +615,15 @@ export class FileBrowserModel implements IDisposable {
   private _pending: Promise<void> | null = null;
   private _pendingPath: string | null = null;
   private _refreshed = new Signal<this, void>(this);
-  private _lastRefresh = -1;
-  private _requested = false;
   private _sessions: Session.IModel[] = [];
   private _state: IStateDB | null = null;
-  private _timeoutId = -1;
-  private _refreshDuration: number;
-  private _baseRefreshDuration: number;
   private _driveName: string;
   private _isDisposed = false;
   private _restored = new PromiseDelegate<void>();
   private _uploads: IUploadModel[] = [];
   private _uploadChanged = new Signal<this, IChangedArgs<IUploadModel>>(this);
   private _unloadEventListener: (e: Event) => string;
+  private _poll: Poll;
 }
 
 /**

tests/test-filebrowser/src/model.spec.ts

@@ -26,7 +26,8 @@ import {
 import {
   acceptDialog,
   dismissDialog,
-  signalToPromises
+  signalToPromises,
+  sleep
 } from '@jupyterlab/testutils';
 import { toArray } from '@phosphor/algorithm';
 
@@ -259,18 +260,15 @@ describe('filebrowser/model', () => {
           opener,
           manager: delayedServiceManager
         });
-        model = new FileBrowserModel({ manager, state });
+        model = new FileBrowserModel({ manager, state }); // Should delay 1000ms
 
-        const paths: string[] = [];
         // An initial refresh is called in the constructor.
         // If it is too slow, it can come in after the directory change,
         // causing a directory set by, e.g., the tree handler to be wrong.
         // This checks to make sure we are handling that case correctly.
-        const refresh = model.refresh().then(() => paths.push(model.path));
-        const cd = model.cd('src').then(() => paths.push(model.path));
-        await Promise.all([refresh, cd]);
+        await model.cd('src'); // should delay 500ms
+        await sleep(2000);
         expect(model.path).to.equal('src');
-        expect(paths).to.eql(['', 'src']);
 
         manager.dispose();
         delayedServiceManager.contents.dispose();