Added an async task manager to the visual console client

Former-commit-id: 4f5c92a976ae976e77cc11505c7a57bf31121930

pandora_console/include/javascript/pandora_visual_console.js

@@ -1,5 +1,5 @@
 // TODO: Add Artica ST header.
-/* globals jQuery, VisualConsole */
+/* globals jQuery, VisualConsole, AsyncTaskManager */
 
 /*
  * *********************
@@ -28,63 +28,68 @@ function createVisualConsole(
   updateInterval,
   onUpdate
 ) {
-  var visualConsole = null;
-  var linkedVCRequest = null;
-  var updateVCRequest = null;
-
   if (container == null || props == null || items == null) return null;
   if (baseUrl == null) baseUrl = "";
 
-  // Code which will be executed between intervals.
-  var intervalRef = null;
-  var stopInterval = function() {
-    if (intervalRef !== null) window.clearInterval(intervalRef);
-  };
-  var startInterval = function() {
-    if (updateInterval == null || updateInterval <= 0) return;
-    stopInterval();
+  var visualConsole = null;
+  var asyncTaskManager = new AsyncTaskManager();
 
-    intervalRef = window.setInterval(function() {
-      if (updateVCRequest !== null) updateVCRequest.abort();
-      updateVCRequest = loadVisualConsoleData(
-        baseUrl,
-        visualConsole.props.id,
-        function(error, data) {
-          if (error) {
-            console.log(
-              "[ERROR]",
-              "[VISUAL-CONSOLE-CLIENT]",
-              "[API]",
-              error.message
-            );
-            return;
+  function updateVisualConsole(visualConsoleId, updateInterval) {
+    asyncTaskManager.add(
+      "visual-console",
+      function(done) {
+        var abortable = loadVisualConsoleData(
+          baseUrl,
+          visualConsoleId,
+          function(error, data) {
+            if (error) {
+              console.log(
+                "[ERROR]",
+                "[VISUAL-CONSOLE-CLIENT]",
+                "[API]",
+                error.message
+              );
+              done();
+              return;
+            }
+
+            // Replace Visual Console.
+            if (data != null && data.props != null && data.items != null) {
+              try {
+                var props =
+                  typeof data.props === "string"
+                    ? JSON.parse(data.props)
+                    : data.props;
+                var items =
+                  typeof data.items === "string"
+                    ? JSON.parse(data.items)
+                    : data.items;
+
+                var prevProps = visualConsole.props;
+                // Update the data structure.
+                visualConsole.props = props;
+                // Update the items.
+                visualConsole.updateElements(items);
+                // Emit the VC update event.
+                if (onUpdate) onUpdate(prevProps, visualConsole.props);
+              } catch (ignored) {} // eslint-disable-line no-empty
+
+              done();
+            }
           }
+        );
 
-          // Replace Visual Console.
-          if (data != null && data.props != null && data.items != null) {
-            try {
-              var props =
-                typeof data.props === "string"
-                  ? JSON.parse(data.props)
-                  : data.props;
-              var items =
-                typeof data.items === "string"
-                  ? JSON.parse(data.items)
-                  : data.items;
-
-              var prevProps = visualConsole.props;
-              // Update the data structure.
-              visualConsole.props = props;
-              // Update the items.
-              visualConsole.updateElements(items);
-              // Emit the VC update event.
-              if (onUpdate) onUpdate(prevProps, visualConsole.props);
-            } catch (ignored) {} // eslint-disable-line no-empty
+        return {
+          cancel: function() {
+            abortable.abort();
           }
-        }
-      );
-    }, updateInterval);
-  };
+        };
+      },
+      updateInterval
+    );
+
+    asyncTaskManager.init("visual-console");
+  }
 
   // Initialize the Visual Console.
   try {
@@ -102,64 +107,23 @@ function createVisualConsole(
       ) {
         // Stop the current link behavior.
         e.nativeEvent.preventDefault();
-
         // Fetch and update the old VC with the new.
-        if (linkedVCRequest !== null) linkedVCRequest.abort();
-        linkedVCRequest = loadVisualConsoleData(
-          baseUrl,
-          e.data.linkedLayoutId,
-          function(error, data) {
-            if (error) {
-              console.log(
-                "[ERROR]",
-                "[VISUAL-CONSOLE-CLIENT]",
-                "[API]",
-                error.message
-              );
-              return;
-            }
-
-            // Replace Visual Console.
-            if (data != null && data.props != null && data.items != null) {
-              // Cancel the old VC updates.
-              stopInterval();
-
-              try {
-                var props =
-                  typeof data.props === "string"
-                    ? JSON.parse(data.props)
-                    : data.props;
-                var items =
-                  typeof data.items === "string"
-                    ? JSON.parse(data.items)
-                    : data.items;
-
-                if (updateVCRequest !== null) updateVCRequest.abort();
-                // Save the old props.
-                var prevProps = visualConsole.props;
-                // Update the data structure.
-                visualConsole.props = props;
-                // Update the items.
-                visualConsole.updateElements(items);
-                // Emit the VC update event.
-                if (onUpdate) onUpdate(prevProps, visualConsole.props);
-              } catch (ignored) {} // eslint-disable-line no-empty
-
-              // Restart the updates.
-              startInterval();
-            }
-          }
-        );
+        updateVisualConsole(e.data.linkedLayoutId, updateInterval);
       }
     });
 
     // Start an interval to update the Visual Console.
-    startInterval();
+    updateVisualConsole(props.id, updateInterval);
   } catch (error) {
     console.log("[ERROR]", "[VISUAL-CONSOLE-CLIENT]", error.message);
   }
 
-  return visualConsole;
+  return {
+    visualConsole: visualConsole,
+    changeUpdateInterval: function(updateInterval) {
+      updateVisualConsole(visualConsole.props.id, updateInterval);
+    }
+  };
 }
 
 /**

visual_console_client/src/index.ts

@@ -7,8 +7,12 @@
 
 import "./main.css"; // CSS import.
 import VisualConsole from "./VisualConsole";
+import AsyncTaskManager from "./lib/AsyncTaskManager";
 
 // Export the VisualConsole class to the global object.
-
 // eslint-disable-next-line
 (window as any).VisualConsole = VisualConsole;
+
+// Export the AsyncTaskManager class to the global object.
+// eslint-disable-next-line
+(window as any).AsyncTaskManager = AsyncTaskManager;

visual_console_client/src/lib/AsyncTaskManager.ts

@@ -0,0 +1,167 @@
+import TypedEvent, { Disposable, Listener } from "../TypedEvent";
+
+interface Cancellable {
+  cancel(): void;
+}
+
+type AsyncTaskStatus = "waiting" | "started" | "cancelled" | "finished";
+type AsyncTaskInitiator = (done: () => void) => Cancellable;
+
+/**
+ * Defines an async task which can be started and cancelled.
+ * It's possible to observe the status changes of the task.
+ */
+class AsyncTask {
+  private readonly taskInitiator: AsyncTaskInitiator;
+  private cancellable: Cancellable = { cancel: () => {} };
+  private _status: AsyncTaskStatus = "waiting";
+
+  // Event manager for status change events.
+  private readonly statusChangeEventManager = new TypedEvent<AsyncTaskStatus>();
+  // List of references to clean the event listeners.
+  private readonly disposables: Disposable[] = [];
+
+  public constructor(taskInitiator: AsyncTaskInitiator) {
+    this.taskInitiator = taskInitiator;
+  }
+
+  /**
+   * Public setter of the `status` property.
+   * @param status.
+   */
+  public set status(status: AsyncTaskStatus) {
+    this._status = status;
+    this.statusChangeEventManager.emit(status);
+  }
+
+  /**
+   * Public accessor of the `status` property.
+   * @return status.
+   */
+  public get status() {
+    return this._status;
+  }
+
+  /**
+   * Start the async task.
+   */
+  public init(): void {
+    this.cancellable = this.taskInitiator(() => {
+      this.status = "finished";
+    });
+    this.status = "started";
+  }
+
+  /**
+   * Cancel the async task.
+   */
+  public cancel(): void {
+    this.cancellable.cancel();
+    this.status = "cancelled";
+  }
+
+  /**
+   * Add an event handler to the status change.
+   * @param listener Function which is going to be executed when the status changes.
+   */
+  public onStatusChange(listener: Listener<AsyncTaskStatus>): Disposable {
+    /*
+     * The '.on' function returns a function which will clean the event
+     * listener when executed. We store all the 'dispose' functions to
+     * call them when the item should be cleared.
+     */
+    const disposable = this.statusChangeEventManager.on(listener);
+    this.disposables.push(disposable);
+
+    return disposable;
+  }
+}
+
+/**
+ * Wrap an async task into another which will execute that task indefinitely
+ * every time the tash finnish and the chosen period ends.
+ * Will last until cancellation.
+ *
+ * @param task Async task to execute.
+ * @param period Time in milliseconds to wait until the next async esecution.
+ *
+ * @return A new async task.
+ */
+function asyncPeriodic(task: AsyncTask, period: number): AsyncTask {
+  return new AsyncTask(() => {
+    let ref: number | null = null;
+
+    task.onStatusChange(status => {
+      if (status === "finished") {
+        ref = window.setTimeout(() => {
+          task.init();
+        }, period);
+      }
+    });
+
+    task.init();
+
+    return {
+      cancel: () => {
+        if (ref) clearTimeout(ref);
+        task.cancel();
+      }
+    };
+  });
+}
+
+/**
+ * Manages a list of async tasks.
+ */
+export default class AsyncTaskManager {
+  private tasks: { [identifier: string]: AsyncTask } = {};
+
+  /**
+   * Adds an async task to the manager.
+   *
+   * @param identifier Unique identifier.
+   * @param taskInitiator Function to initialize the async task.
+   * Should return a structure to cancel the task.
+   * @param period Optional period to repeat the task indefinitely.
+   */
+  public add(
+    identifier: string,
+    taskInitiator: AsyncTaskInitiator,
+    period: number | null = null
+  ): AsyncTask {
+    if (this.tasks[identifier] && this.tasks[identifier].status === "started") {
+      this.tasks[identifier].cancel();
+    }
+
+    const asyncTask =
+      period !== null
+        ? asyncPeriodic(new AsyncTask(taskInitiator), period)
+        : new AsyncTask(taskInitiator);
+
+    this.tasks[identifier] = asyncTask;
+
+    return this.tasks[identifier];
+  }
+
+  /**
+   * Starts an async task.
+   *
+   * @param identifier Unique identifier.
+   */
+  public init(identifier: string) {
+    if (this.tasks[identifier] && this.tasks[identifier].status === "waiting") {
+      this.tasks[identifier].init();
+    }
+  }
+
+  /**
+   * Cancel a running async task.
+   *
+   * @param identifier Unique identifier.
+   */
+  public cancel(identifier: string) {
+    if (this.tasks[identifier] && this.tasks[identifier].status === "started") {
+      this.tasks[identifier].cancel();
+    }
+  }
+}

visual_console_client/src/lib/index.ts

@@ -6,7 +6,7 @@ import {
   WithModuleProps,
   LinkedVisualConsoleProps,
   LinkedVisualConsolePropsStatus
-} from "./types";
+} from "../types";
 
 /**
  * Return a number or a default value from a raw value.
@@ -14,8 +14,7 @@ import {
  * @param defaultValue Default value to use if we cannot extract a valid number.
  * @return A valid number or the default value.
  */
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function parseIntOr<T>(value: any, defaultValue: T): number | T {
+export function parseIntOr<T>(value: unknown, defaultValue: T): number | T {
   if (typeof value === "number") return value;
   if (typeof value === "string" && value.length > 0 && !isNaN(parseInt(value)))
     return parseInt(value);
@@ -28,8 +27,7 @@ export function parseIntOr<T>(value: any, defaultValue: T): number | T {
  * @param defaultValue Default value to use if we cannot extract a valid number.
  * @return A valid number or the default value.
  */
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function parseFloatOr<T>(value: any, defaultValue: T): number | T {
+export function parseFloatOr<T>(value: unknown, defaultValue: T): number | T {
   if (typeof value === "number") return value;
   if (
     typeof value === "string" &&
@@ -55,8 +53,10 @@ export function stringIsEmpty(value?: string | null): boolean {
  * @param defaultValue Default value to use if we cannot extract a non empty string.
  * @return A non empty string or the default value.
  */
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function notEmptyStringOr<T>(value: any, defaultValue: T): string | T {
+export function notEmptyStringOr<T>(
+  value: unknown,
+  defaultValue: T
+): string | T {
   return typeof value === "string" && value.length > 0 ? value : defaultValue;
 }
 
@@ -65,8 +65,7 @@ export function notEmptyStringOr<T>(value: any, defaultValue: T): string | T {
  * @param value Raw value from which we will try to extract the boolean.
  * @return A valid boolean value. false by default.
  */
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function parseBoolean(value: any): boolean {
+export function parseBoolean(value: unknown): boolean {
   if (typeof value === "boolean") return value;
   else if (typeof value === "number") return value > 0;
   else if (typeof value === "string") return value === "1" || value === "true";

visual_console_client/src/lib/spec.ts

@@ -8,7 +8,7 @@ import {
   humanDate,
   humanTime,
   replaceMacros
-} from "./lib";
+} from ".";
 
 describe("function parseIntOr", () => {
   it("should retrieve valid int or a default value", () => {