NativeScript · mudlabs · Jul 13, 2019 · Jul 13, 2019 · Jul 13, 2019 · Jul 13, 2019
diff --git a/tns-core-modules/file-system/file-system-worker/components.ts b/tns-core-modules/file-system/file-system-worker/components.ts
@@ -0,0 +1,187 @@
+import { on, off, lowMemoryEvent } from "../../application";
+
+interface WorkerJob {
+  id: string;
+  onError: { (error: any): void };
+  onSuccess: { (message: any): void };
+}
+
+export namespace FSWorker {
+  export enum WorkType {
+    file,
+    folder,
+    entity,
+    worker
+  }
+
+  export enum WorkTask {
+    readText,
+    writeText,
+    clearFolder,
+    getEntities,
+    removeEntity,
+    renameEntity,
+    closeWorker,
+    turnOffActivityObserver
+  }
+
+  export enum State {
+    inactive = "WorkerBecameInactive",
+    closed = "WorkerCloseRequestFulfilled"
+  }
+
+  let fileWorker: Instance;
+  export const isRunning = (): boolean => fileWorker instanceof Instance;
+  export const getWorkerInstance = (): Instance => fileWorker;
+  export const createWorkerInstance = (): Instance =>
+    (fileWorker = new Instance());
+
+  export const onMemoryEvent = (callback, thisArg) =>
+    on(lowMemoryEvent, callback, thisArg);
+  export const offMemoryEvent = (callback, thisArg) =>
+    off(lowMemoryEvent, callback, thisArg);
+
+  export class Job {
+    id: string;
+    object: any;
+    task: WorkTask;
+    type: WorkType;
+
+    constructor(type: WorkType, task: WorkTask, object?: any) {
+      this.id = `${type}-${task}-${Date.now()}`;
+      this.object = object;
+      this.task = task;
+      this.type = type;
+    }
+  }
+
+  export class Instance {
+    private _worker: Worker;
+    private _jobs: WorkerJob[];
+
+    constructor() {
+      this._jobs = [];
+      this._worker = new Worker("./worker");
+      this._worker.onerror = error => {
+        const data = JSON.parse(error.message);
+        this.getJob(data.id).onError(new Error(data.message));
+      };
+      this._worker.onmessage = message => {
+        const data = message.data;
+        switch (data.id) {
+          case "WorkerCloseRequestFulfilled":
+            this.onWorkerClosed();
+            break;
+          case "WorkerBecameInactive":
+            this.onWorkerClosed();
+            break;
+          default:
+            this.getJob(data.id).onSuccess(data.message);
+        }
+      };
+      FSWorker.onMemoryEvent(this.closeWorker, this);
+    }
+
+    public get jobs() {
+      return this._jobs;
+    }
+
+    public getJob(id: string): WorkerJob {
+      const job = this.jobs.find(job => job.id === id);
+      this.jobs.splice(this.jobs.indexOf(job), 1);
+      return job;
+    }
+
+    public postJob(job: Job, onSuccess, onError): void {
+      this.jobs.push({ id: job.id, onSuccess, onError });
+      this._worker.postMessage(job);
+    }
+
+    keepAlive(callback: { (message: string): void } = (): void => {}) {
+      this.postJob(
+        new Job(WorkType.worker, WorkTask.turnOffActivityObserver),
+        callback,
+        callback
+      );
+    }
+
+    terminate() {
+      this.keepAlive(() => {
+        this._worker.terminate();
+        this.onWorkerClosed();
+      });
+    }
+
+    closeWorker() {
+      this._worker.postMessage({
+        id: State.closed,
+        type: WorkType.worker,
+        task: WorkTask.closeWorker
+      });
+    }
+
+    onWorkerClosed() {
+      FSWorker.offMemoryEvent(this.closeWorker, this);
+      this.jobs.splice(0, this.jobs.length - 1);
+      fileWorker = null;
+    }
+  }
+}
+
+export class WorkerTimer {
+  private _id: any;
+  private _time: number;
+  private _duration: number;
+  private _observing: boolean;
+  private _onEnd: { (): void };
+  private _becameInactive: boolean;
+
+  constructor(onEnd) {
+    this._becameInactive = false;
+    this._duration = 120000;
+    this._observing = true;
+    this._onEnd = onEnd;
+    this._time = 0;
+
+    this.startTimer();
+  }
+
+  private _incrementTime() {
+    this._time += 1000;
+    if (this._time >= this._duration) {
+      this.stopTimer();
+      this._becameInactive = true;
+      this._onEnd();
+    }
+  }
+
+  private get _isRunning() {
+    return typeof this._id === "number";
+  }
+
+  private get _isObserving() {
+    return this._observing;
+  }
+
+  public get becameInactive() {
+    return this._becameInactive;
+  }
+
+  public stopObserving() {
+    this.stopTimer();
+    this._observing = false;
+  }
+
+  public startTimer() {
+    if (this._isObserving && !this._isRunning) {
+      this._id = setInterval(() => this._incrementTime(), 1000);
+    }
+  }
+
+  public stopTimer() {
+    if (this._isObserving && this._isRunning) {
+      clearInterval(this._id);
+      this._id = null;
+    }
+  }
+}