content: /*
   * Copyright (C) 2008 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package dev.dworks.apps.anexplorer.misc;
  
  import java.util.ArrayDeque;
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.Callable;
  import java.util.concurrent.CancellationException;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Executor;
  import java.util.concurrent.Executors;
  import java.util.concurrent.FutureTask;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import android.annotation.TargetApi;
  import android.os.Handler;
  import android.os.Message;
  import android.os.Process;
  
  /**
   * *************************************
   * Copied from JB release framework:
   * https://android.googlesource.com/platform/frameworks/base/+/jb-release/core/java/android/os/AsyncTask.java
   *
   * so that threading behavior on all OS versions is the same and we can tweak behavior by using
   * executeOnExecutor() if needed.
   *
   * There are 3 changes in this copy of AsyncTask:
   *    -pre-HC a single thread executor is used for serial operation
   *    (Executors.newSingleThreadExecutor) and is the default
   *    -the default THREAD_POOL_EXECUTOR was changed to use DiscardOldestPolicy
   *    -a new fixed thread pool called DUAL_THREAD_EXECUTOR was added
   * *************************************
   *
   * <p>AsyncTask enables proper and easy use of the UI thread. This class allows to
   * perform background operations and publish results on the UI thread without
   * having to manipulate threads and/or handlers.</p>
   *
   * <p>AsyncTask is designed to be a helper class around {@link Thread} and {@link Handler}
   * and does not constitute a generic threading framework. AsyncTasks should ideally be
   * used for short operations (a few seconds at the most.) If you need to keep threads
   * running for long periods of time, it is highly recommended you use the various APIs
   * provided by the <code>java.util.concurrent</code> pacakge such as {@link Executor},
   * {@link ThreadPoolExecutor} and {@link FutureTask}.</p>
   *
   * <p>An asynchronous task is defined by a computation that runs on a background thread and
   * whose result is published on the UI thread. An asynchronous task is defined by 3 generic
   * types, called <code>Params</code>, <code>Progress</code> and <code>Result</code>,
   * and 4 steps, called <code>onPreExecute</code>, <code>doInBackground</code>,
   * <code>onProgressUpdate</code> and <code>onPostExecute</code>.</p>
   *
   * <div class="special reference">
   * <h3>Developer Guides</h3>
   * <p>For more information about using tasks and threads, read the
   * <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html">Processes and
   * Threads</a> developer guide.</p>
   * </div>
   *
   * <h2>Usage</h2>
   * <p>AsyncTask must be subclassed to be used. The subclass will override at least
   * one method ({@link #doInBackground}), and most often will override a
   * second one ({@link #onPostExecute}.)</p>
   *
   * <p>Here is an example of subclassing:</p>
   * <pre class="prettyprint">
   * private class DownloadFilesTask extends AsyncTask&lt;URL, Integer, Long&gt; {
   *     protected Long doInBackground(URL... urls) {
   *         int count = urls.length;
   *         long totalSize = 0;
   *         for (int i = 0; i < count; i++) {
   *             totalSize += Downloader.downloadFile(urls[i]);
   *             publishProgress((int) ((i / (float) count) * 100));
   *             // Escape early if cancel() is called
   *             if (isCancelled()) break;
   *         }
   *         return totalSize;
   *     }
   *
   *     protected void onProgressUpdate(Integer... progress) {
   *         setProgressPercent(progress[0]);
   *     }
   *
   *     protected void onPostExecute(Long result) {
   *         showDialog("Downloaded " + result + " bytes");
   *     }
   * }
   * </pre>
   *
   * <p>Once created, a task is executed very simply:</p>
   * <pre class="prettyprint">
   * new DownloadFilesTask().execute(url1, url2, url3);
   * </pre>
   *
   * <h2>AsyncTask's generic types</h2>
   * <p>The three types used by an asynchronous task are the following:</p>
   * <ol>
   *     <li><code>Params</code>, the type of the parameters sent to the task upon
   *     execution.</li>
   *     <li><code>Progress</code>, the type of the progress units published during
   *     the background computation.</li>
   *     <li><code>Result</code>, the type of the result of the background
   *     computation.</li>
   * </ol>
   * <p>Not all types are always used by an asynchronous task. To mark a type as unused,
   * simply use the type {@link Void}:</p>
   * <pre>
   * private class MyTask extends AsyncTask&lt;Void, Void, Void&gt; { ... }
   * </pre>
   *
   * <h2>The 4 steps</h2>
   * <p>When an asynchronous task is executed, the task goes through 4 steps:</p>
   * <ol>
   *     <li>{@link #onPreExecute()}, invoked on the UI thread immediately after the task
   *     is executed. This step is normally used to setup the task, for instance by
   *     showing a progress bar in the user interface.</li>
   *     <li>{@link #doInBackground}, invoked on the background thread
   *     immediately after {@link #onPreExecute()} finishes executing. This step is used
   *     to perform background computation that can take a long time. The parameters
   *     of the asynchronous task are passed to this step. The result of the computation must
   *     be returned by this step and will be passed back to the last step. This step
   *     can also use {@link #publishProgress} to publish one or more units
   *     of progress. These values are published on the UI thread, in the
   *     {@link #onProgressUpdate} step.</li>
   *     <li>{@link #onProgressUpdate}, invoked on the UI thread after a
   *     call to {@link #publishProgress}. The timing of the execution is
   *     undefined. This method is used to display any form of progress in the user
   *     interface while the background computation is still executing. For instance,
   *     it can be used to animate a progress bar or show logs in a text field.</li>
   *     <li>{@link #onPostExecute}, invoked on the UI thread after the background
   *     computation finishes. The result of the background computation is passed to
   *     this step as a parameter.</li>
   * </ol>
   *
   * <h2>Cancelling a task</h2>
   * <p>A task can be cancelled at any time by invoking {@link #cancel(boolean)}. Invoking
   * this method will cause subsequent calls to {@link #isCancelled()} to return true.
   * After invoking this method, {@link #onCancelled(Object)}, instead of
   * {@link #onPostExecute(Object)} will be invoked after {@link #doInBackground(Object[])}
   * returns. To ensure that a task is cancelled as quickly as possible, you should always
   * check the return value of {@link #isCancelled()} periodically from
   * {@link #doInBackground(Object[])}, if possible (inside a loop for instance.)</p>
   *
   * <h2>Threading rules</h2>
   * <p>There are a few threading rules that must be followed for this class to
   * work properly:</p>
   * <ul>
   *     <li>The AsyncTask class must be loaded on the UI thread. This is done
   *     automatically as of {@link android.os.Build.VERSION_CODES#JELLY_BEAN}.</li>
   *     <li>The task instance must be created on the UI thread.</li>
   *     <li>{@link #execute} must be invoked on the UI thread.</li>
   *     <li>Do not call {@link #onPreExecute()}, {@link #onPostExecute},
   *     {@link #doInBackground}, {@link #onProgressUpdate} manually.</li>
   *     <li>The task can be executed only once (an exception will be thrown if
   *     a second execution is attempted.)</li>
   * </ul>
   *
   * <h2>Memory observability</h2>
   * <p>AsyncTask guarantees that all callback calls are synchronized in such a way that the following
   * operations are safe without explicit synchronizations.</p>
   * <ul>
   *     <li>Set member fields in the constructor or {@link #onPreExecute}, and refer to them
   *     in {@link #doInBackground}.
   *     <li>Set member fields in {@link #doInBackground}, and refer to them in
   *     {@link #onProgressUpdate} and {@link #onPostExecute}.
   * </ul>
   *
   * <h2>Order of execution</h2>
   * <p>When first introduced, AsyncTasks were executed serially on a single background
   * thread. Starting with {@link android.os.Build.VERSION_CODES#DONUT}, this was changed
   * to a pool of threads allowing multiple tasks to operate in parallel. Starting with
   * {@link android.os.Build.VERSION_CODES#HONEYCOMB}, tasks are executed on a single
   * thread to avoid common application errors caused by parallel execution.</p>
   * <p>If you truly want parallel execution, you can invoke
   * {@link #executeOnExecutor(java.util.concurrent.Executor, Object[])} with
   * {@link #THREAD_POOL_EXECUTOR}.</p>
   */
  public abstract class AsyncTask<Params, Progress, Result> {
      private static final String LOG_TAG = "AsyncTask";
  
      private static final int CORE_POOL_SIZE = 5;
      private static final int MAXIMUM_POOL_SIZE = 128;
      private static final int KEEP_ALIVE = 1;
  
      private static final ThreadFactory  sThreadFactory = new ThreadFactory() {
          private final AtomicInteger mCount = new AtomicInteger(1);
  
          public Thread newThread(Runnable r) {
              return new Thread(r, "AsyncTask #" + mCount.getAndIncrement());
          }
      };
  
      private static final BlockingQueue<Runnable> sPoolWorkQueue =
              new LinkedBlockingQueue<Runnable>(10);
  
      /**
       * An {@link Executor} that can be used to execute tasks in parallel.
       */
      public static final Executor THREAD_POOL_EXECUTOR
              = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
              TimeUnit.SECONDS, sPoolWorkQueue, sThreadFactory,
              new ThreadPoolExecutor.DiscardOldestPolicy());
  
      /**
       * An {@link Executor} that executes tasks one at a time in serial
       * order.  This serialization is global to a particular process.
       */
      public static final Executor SERIAL_EXECUTOR = Executors.newSingleThreadExecutor(sThreadFactory);
  
      private static final int MESSAGE_POST_RESULT = 0x1;
      private static final int MESSAGE_POST_PROGRESS = 0x2;
  
      private static final InternalHandler sHandler = new InternalHandler();
  
      private static volatile Executor sDefaultExecutor = SERIAL_EXECUTOR;
      private final WorkerRunnable<Params, Result> mWorker;
      private final FutureTask<Result> mFuture;
  
      private volatile Status mStatus = Status.PENDING;
  
      private final AtomicBoolean mCancelled = new AtomicBoolean();
      private final AtomicBoolean mTaskInvoked = new AtomicBoolean();
  
      @TargetApi(11)
      private static class SerialExecutor implements Executor {
          final ArrayDeque<Runnable> mTasks = new ArrayDeque<Runnable>();
          Runnable mActive;
  
          public synchronized void execute(final Runnable r) {
              mTasks.offer(new Runnable() {
                  public void run() {
                      try {
                          r.run();
                      } finally {
                          scheduleNext();
                      }
                  }
              });
              if (mActive == null) {
                  scheduleNext();
              }
          }
  
          protected synchronized void scheduleNext() {
              if ((mActive = mTasks.poll()) != null) {
                  THREAD_POOL_EXECUTOR.execute(mActive);
              }
          }
      }
  
      /**
       * Indicates the current status of the task. Each status will be set only once
       * during the lifetime of a task.
       */
      public enum Status {
          /**
           * Indicates that the task has not been executed yet.
           */
          PENDING,
          /**
           * Indicates that the task is running.
           */
          RUNNING,
          /**
           * Indicates that {@link AsyncTask#onPostExecute} has finished.
           */
          FINISHED,
      }
  
      /** @hide Used to force static handler to be created. */
      public static void init() {
          sHandler.getLooper();
      }
  
      /** @hide */
      public static void setDefaultExecutor(Executor exec) {
          sDefaultExecutor = exec;
      }
  
      /**
       * Creates a new asynchronous task. This constructor must be invoked on the UI thread.
       */
      public AsyncTask() {
          mWorker = new WorkerRunnable<Params, Result>() {
              public Result call() throws Exception {
                  mTaskInvoked.set(true);
  
                  Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
                  //noinspection unchecked
                  return postResult(doInBackground(mParams));
              }
          };
  
          mFuture = new FutureTask<Result>(mWorker) {
              @Override
              protected void done() {
                  try {
                      postResultIfNotInvoked(get());
                  } catch (InterruptedException e) {
                      android.util.Log.w(LOG_TAG, e);
                  } catch (ExecutionException e) {
                      throw new RuntimeException("An error occured while executing doInBackground()",
                              e.getCause());
                  } catch (CancellationException e) {
                      postResultIfNotInvoked(null);
                  }
              }
          };
      }
  
      private void postResultIfNotInvoked(Result result) {
          final boolean wasTaskInvoked = mTaskInvoked.get();
          if (!wasTaskInvoked) {
              postResult(result);
          }
      }
  
      private Result postResult(Result result) {
          @SuppressWarnings("unchecked")
          Message message = sHandler.obtainMessage(MESSAGE_POST_RESULT,
                  new AsyncTaskResult<Result>(this, result));
          message.sendToTarget();
          return result;
      }
  
      /**
       * Returns the current status of this task.
       *
       * @return The current status.
       */
      public final Status getStatus() {
          return mStatus;
      }
  
      /**
       * Override this method to perform a computation on a background thread. The
       * specified parameters are the parameters passed to {@link #execute}
       * by the caller of this task.
       *
       * This method can call {@link #publishProgress} to publish updates
       * on the UI thread.
       *
       * @param params The parameters of the task.
       *
       * @return A result, defined by the subclass of this task.
       *
       * @see #onPreExecute()
       * @see #onPostExecute
       * @see #publishProgress
       */
      protected abstract Result doInBackground(Params... params);
  
      /**
       * Runs on the UI thread before {@link #doInBackground}.
       *
       * @see #onPostExecute
       * @see #doInBackground
       */
      protected void onPreExecute() {
      }
  
      /**
       * <p>Runs on the UI thread after {@link #doInBackground}. The
       * specified result is the value returned by {@link #doInBackground}.</p>
       *
       * <p>This method won't be invoked if the task was cancelled.</p>
       *
       * @param result The result of the operation computed by {@link #doInBackground}.
       *
       * @see #onPreExecute
       * @see #doInBackground
       * @see #onCancelled(Object)
       */
      protected void onPostExecute(Result result) {
      }
  
      /**
       * Runs on the UI thread after {@link #publishProgress} is invoked.
       * The specified values are the values passed to {@link #publishProgress}.
       *
       * @param values The values indicating progress.
       *
       * @see #publishProgress
       * @see #doInBackground
       */
      protected void onProgressUpdate(Progress... values) {
      }
  
      /**
       * <p>Runs on the UI thread after {@link #cancel(boolean)} is invoked and
       * {@link #doInBackground(Object[])} has finished.</p>
       *
       * <p>The default implementation simply invokes {@link #onCancelled()} and
       * ignores the result. If you write your own implementation, do not call
       * <code>super.onCancelled(result)</code>.</p>
       *
       * @param result The result, if any, computed in
       *               {@link #doInBackground(Object[])}, can be null
       *
       * @see #cancel(boolean)
       * @see #isCancelled()
       */
      protected void onCancelled(Result result) {
          onCancelled();
      }
  
      /**
       * <p>Applications should preferably override {@link #onCancelled(Object)}.
       * This method is invoked by the default implementation of
       * {@link #onCancelled(Object)}.</p>
       *
       * <p>Runs on the UI thread after {@link #cancel(boolean)} is invoked and
       * {@link #doInBackground(Object[])} has finished.</p>
       *
       * @see #onCancelled(Object)
       * @see #cancel(boolean)
       * @see #isCancelled()
       */
      protected void onCancelled() {
      }
  
      /**
       * Returns <tt>true</tt> if this task was cancelled before it completed
       * normally. If you are calling {@link #cancel(boolean)} on the task,
       * the value returned by this method should be checked periodically from
       * {@link #doInBackground(Object[])} to end the task as soon as possible.
       *
       * @return <tt>true</tt> if task was cancelled before it completed
       *
       * @see #cancel(boolean)
       */
      public final boolean isCancelled() {
          return mCancelled.get();
      }
  
      /**
       * <p>Attempts to cancel execution of this task.  This attempt will
       * fail if the task has already completed, already been cancelled,
       * or could not be cancelled for some other reason. If successful,
       * and this task has not started when <tt>cancel</tt> is called,
       * this task should never run. If the task has already started,
       * then the <tt>mayInterruptIfRunning</tt> parameter determines
       * whether the thread executing this task should be interrupted in
       * an attempt to stop the task.</p>
       *
       * <p>Calling this method will result in {@link #onCancelled(Object)} being
       * invoked on the UI thread after {@link #doInBackground(Object[])}
       * returns. Calling this method guarantees that {@link #onPostExecute(Object)}
       * is never invoked. After invoking this method, you should check the
       * value returned by {@link #isCancelled()} periodically from
       * {@link #doInBackground(Object[])} to finish the task as early as
       * possible.</p>
       *
       * @param mayInterruptIfRunning <tt>true</tt> if the thread executing this
       *        task should be interrupted; otherwise, in-progress tasks are allowed
       *        to complete.
       *
       * @return <tt>false</tt> if the task could not be cancelled,
       *         typically because it has already completed normally;
       *         <tt>true</tt> otherwise
       *
       * @see #isCancelled()
       * @see #onCancelled(Object)
       */
      public final boolean cancel(boolean mayInterruptIfRunning) {
          mCancelled.set(true);
          return mFuture.cancel(mayInterruptIfRunning);
      }
  
      /**
       * Waits if necessary for the computation to complete, and then
       * retrieves its result.
       *
       * @return The computed result.
       *
       * @throws CancellationException If the computation was cancelled.
       * @throws ExecutionException If the computation threw an exception.
       * @throws InterruptedException If the current thread was interrupted
       *         while waiting.
       */
      public final Result get() throws InterruptedException, ExecutionException {
          return mFuture.get();
      }
  
      /**
       * Waits if necessary for at most the given time for the computation
       * to complete, and then retrieves its result.
       *
       * @param timeout Time to wait before cancelling the operation.
       * @param unit The time unit for the timeout.
       *
       * @return The computed result.
       *
       * @throws CancellationException If the computation was cancelled.
       * @throws ExecutionException If the computation threw an exception.
       * @throws InterruptedException If the current thread was interrupted
       *         while waiting.
       * @throws TimeoutException If the wait timed out.
       */
      public final Result get(long timeout, TimeUnit unit) throws InterruptedException,
              ExecutionException, TimeoutException {
          return mFuture.get(timeout, unit);
      }
  
      /**
       * Executes the task with the specified parameters. The task returns
       * itself (this) so that the caller can keep a reference to it.
       *
       * <p>Note: this function schedules the task on a queue for a single background
       * thread or pool of threads depending on the platform version.  When first
       * introduced, AsyncTasks were executed serially on a single background thread.
       * Starting with {@link android.os.Build.VERSION_CODES#DONUT}, this was changed
       * to a pool of threads allowing multiple tasks to operate in parallel. Starting
       * {@link android.os.Build.VERSION_CODES#HONEYCOMB}, tasks are back to being
       * executed on a single thread to avoid common application errors caused
       * by parallel execution.  If you truly want parallel execution, you can use
       * the {@link #executeOnExecutor} version of this method
       * with {@link #THREAD_POOL_EXECUTOR}; however, see commentary there for warnings
       * on its use.
       *
       * <p>This method must be invoked on the UI thread.
       *
       * @param params The parameters of the task.
       *
       * @return This instance of AsyncTask.
       *
       * @throws IllegalStateException If {@link #getStatus()} returns either
       *         {@link AsyncTask.Status#RUNNING} or {@link AsyncTask.Status#FINISHED}.
       *
       * @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
       * @see #execute(Runnable)
       */
      public final AsyncTask<Params, Progress, Result> execute(Params... params) {
          return executeOnExecutor(sDefaultExecutor, params);
      }
  
      /**
       * Executes the task with the specified parameters. The task returns
       * itself (this) so that the caller can keep a reference to it.
       *
       * <p>This method is typically used with {@link #THREAD_POOL_EXECUTOR} to
       * allow multiple tasks to run in parallel on a pool of threads managed by
       * AsyncTask, however you can also use your own {@link Executor} for custom
       * behavior.
       *
       * <p><em>Warning:</em> Allowing multiple tasks to run in parallel from
       * a thread pool is generally <em>not</em> what one wants, because the order
       * of their operation is not defined.  For example, if these tasks are used
       * to modify any state in common (such as writing a file due to a button click),
       * there are no guarantees on the order of the modifications.
       * Without careful work it is possible in rare cases for the newer version
       * of the data to be over-written by an older one, leading to obscure data
       * loss and stability issues.  Such changes are best
       * executed in serial; to guarantee such work is serialized regardless of
       * platform version you can use this function with {@link #SERIAL_EXECUTOR}.
       *
       * <p>This method must be invoked on the UI thread.
       *
       * @param exec The executor to use.  {@link #THREAD_POOL_EXECUTOR} is available as a
       *              convenient process-wide thread pool for tasks that are loosely coupled.
       * @param params The parameters of the task.
       *
       * @return This instance of AsyncTask.
       *
       * @throws IllegalStateException If {@link #getStatus()} returns either
       *         {@link AsyncTask.Status#RUNNING} or {@link AsyncTask.Status#FINISHED}.
       *
       * @see #execute(Object[])
       */
      public final AsyncTask<Params, Progress, Result> executeOnExecutor(Executor exec,
              Params... params) {
          if (mStatus != Status.PENDING) {
              switch (mStatus) {
                  case RUNNING:
                      throw new IllegalStateException("Cannot execute task:"
                              + " the task is already running.");
                  case FINISHED:
                      throw new IllegalStateException("Cannot execute task:"
                              + " the task has already been executed "
                              + "(a task can be executed only once)");
  				case PENDING:
  					break;
  				default:
  					break;
              }
          }
  
          mStatus = Status.RUNNING;
  
          onPreExecute();
  
          mWorker.mParams = params;
          exec.execute(mFuture);
  
          return this;
      }
  
      /**
       * Convenience version of {@link #execute(Object...)} for use with
       * a simple Runnable object. See {@link #execute(Object[])} for more
       * information on the order of execution.
       *
       * @see #execute(Object[])
       * @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
       */
      public static void execute(Runnable runnable) {
          sDefaultExecutor.execute(runnable);
      }
  
      /**
       * This method can be invoked from {@link #doInBackground} to
       * publish updates on the UI thread while the background computation is
       * still running. Each call to this method will trigger the execution of
       * {@link #onProgressUpdate} on the UI thread.
       *
       * {@link #onProgressUpdate} will note be called if the task has been
       * canceled.
       *
       * @param values The progress values to update the UI with.
       *
       * @see #onProgressUpdate
       * @see #doInBackground
       */
      protected final void publishProgress(Progress... values) {
          if (!isCancelled()) {
              sHandler.obtainMessage(MESSAGE_POST_PROGRESS,
                      new AsyncTaskResult<Progress>(this, values)).sendToTarget();
          }
      }
  
      private void finish(Result result) {
          if (isCancelled()) {
              onCancelled(result);
          } else {
              onPostExecute(result);
          }
          mStatus = Status.FINISHED;
      }
  
      private static class InternalHandler extends Handler {
          @SuppressWarnings({ "rawtypes", "unchecked" })
  		@Override
          public void handleMessage(Message msg) {
              AsyncTaskResult result = (AsyncTaskResult) msg.obj;
              switch (msg.what) {
                  case MESSAGE_POST_RESULT:
                      // There is only one result
                      result.mTask.finish(result.mData[0]);
                      break;
                  case MESSAGE_POST_PROGRESS:
                      result.mTask.onProgressUpdate(result.mData);
                      break;
              }
          }
      }
  
      private static abstract class WorkerRunnable<Params, Result> implements Callable<Result> {
          Params[] mParams;
      }
      
      @SuppressWarnings("rawtypes")
      private static class AsyncTaskResult<Data> {
  		final AsyncTask mTask;
          final Data[] mData;
  
          AsyncTaskResult(AsyncTask task, Data... data) {
              mTask = task;
              mData = data;
          }
      }
  }