src/com/android/documentsui/services/FileOperationService.java - platform/packages/apps/DocumentsUI - Git at Google

 /*
  * Copyright (C) 2015 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 com.android.documentsui.services;

 import static com.android.documentsui.base.SharedMinimal.DEBUG;

 import android.annotation.IntDef;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.app.Service;
 import android.content.Intent;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.PowerManager;
 import android.os.UserManager;
 import android.support.annotation.VisibleForTesting;
 import android.util.Log;

 import com.android.documentsui.R;
 import com.android.documentsui.base.Features;

 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;

 import javax.annotation.concurrent.GuardedBy;

 public class FileOperationService extends Service implements Job.Listener {

     public static final String TAG = "FileOperationService";

     // Extra used for OperationDialogFragment, Notifications and picking copy destination.
     public static final String EXTRA_OPERATION_TYPE = "com.android.documentsui.OPERATION_TYPE";

     // Extras used for OperationDialogFragment...
     public static final String EXTRA_DIALOG_TYPE = "com.android.documentsui.DIALOG_TYPE";
     public static final String EXTRA_SRC_LIST = "com.android.documentsui.SRC_LIST";

     public static final String EXTRA_FAILED_URIS = "com.android.documentsui.FAILED_URIS";
     public static final String EXTRA_FAILED_DOCS = "com.android.documentsui.FAILED_DOCS";

     // Extras used to start or cancel a file operation...
     public static final String EXTRA_JOB_ID = "com.android.documentsui.JOB_ID";
     public static final String EXTRA_OPERATION = "com.android.documentsui.OPERATION";
     public static final String EXTRA_CANCEL = "com.android.documentsui.CANCEL";

     @IntDef({
             OPERATION_UNKNOWN,
             OPERATION_COPY,
             OPERATION_COMPRESS,
             OPERATION_EXTRACT,
             OPERATION_MOVE,
             OPERATION_DELETE
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface OpType {}
     public static final int OPERATION_UNKNOWN = -1;
     public static final int OPERATION_COPY = 1;
     public static final int OPERATION_EXTRACT = 2;
     public static final int OPERATION_COMPRESS = 3;
     public static final int OPERATION_MOVE = 4;
     public static final int OPERATION_DELETE = 5;

     @IntDef({
             MESSAGE_PROGRESS,
             MESSAGE_FINISH
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface MessageType {}
     public static final int MESSAGE_PROGRESS = 0;
     public static final int MESSAGE_FINISH = 1;

     // TODO: Move it to a shared file when more operations are implemented.
     public static final int FAILURE_COPY = 1;

     static final String NOTIFICATION_CHANNEL_ID = "channel_id";

     private static final int POOL_SIZE = 2;  // "pool size", not *max* "pool size".

     @VisibleForTesting static final int NOTIFICATION_ID_PROGRESS = 1;
     private static final int NOTIFICATION_ID_FAILURE = 2;
     private static final int NOTIFICATION_ID_WARNING = 3;

     // The executor and job factory are visible for testing and non-final
     // so we'll have a way to inject test doubles from the test. It's
     // a sub-optimal arrangement.
     @VisibleForTesting ExecutorService executor;

     // Use a separate thread pool to prioritize deletions.
     @VisibleForTesting ExecutorService deletionExecutor;

     // Use a handler to schedule monitor tasks.
     @VisibleForTesting Handler handler;

     // Use a foreground manager to change foreground state of this service.
     @VisibleForTesting ForegroundManager foregroundManager;

     // Use a notification manager to post and cancel notifications for jobs.
     @VisibleForTesting NotificationManager notificationManager;

     // Use a features to determine if notification channel is enabled.
     @VisibleForTesting Features features;

     @GuardedBy("mJobs")
     private final Map<String, JobRecord> mJobs = new LinkedHashMap<>();

     // The job whose notification is used to keep the service in foreground mode.
     @GuardedBy("mJobs")
     private Job mForegroundJob;

     private PowerManager mPowerManager;
     private PowerManager.WakeLock mWakeLock;  // the wake lock, if held.

     private int mLastServiceId;

     @Override
     public void onCreate() {
         // Allow tests to pre-set these with test doubles.
         if (executor == null) {
             executor = Executors.newFixedThreadPool(POOL_SIZE);
         }

         if (deletionExecutor == null) {
             deletionExecutor = Executors.newCachedThreadPool();
         }

         if (handler == null) {
             // Monitor tasks are small enough to schedule them on main thread.
             handler = new Handler();
         }

         if (foregroundManager == null) {
             foregroundManager = createForegroundManager(this);
         }

         if (notificationManager == null) {
             notificationManager = getSystemService(NotificationManager.class);
         }

         features = new Features.RuntimeFeatures(getResources(), UserManager.get(this));
         setUpNotificationChannel();

         if (DEBUG) Log.d(TAG, "Created.");
         mPowerManager = getSystemService(PowerManager.class);
     }

     private void setUpNotificationChannel() {
         if (features.isNotificationChannelEnabled()) {
             NotificationChannel channel = new NotificationChannel(
                     NOTIFICATION_CHANNEL_ID,
                     getString(R.string.app_label),
                     NotificationManager.IMPORTANCE_LOW);
             notificationManager.createNotificationChannel(channel);
         }
     }

     @Override
     public void onDestroy() {
         if (DEBUG) Log.d(TAG, "Shutting down executor.");

         List<Runnable> unfinishedCopies = executor.shutdownNow();
         List<Runnable> unfinishedDeletions = deletionExecutor.shutdownNow();
         List<Runnable> unfinished =
                 new ArrayList<>(unfinishedCopies.size() + unfinishedDeletions.size());
         unfinished.addAll(unfinishedCopies);
         unfinished.addAll(unfinishedDeletions);
         if (!unfinished.isEmpty()) {
             Log.w(TAG, "Shutting down, but executor reports running jobs: " + unfinished);
         }

         executor = null;
         deletionExecutor = null;
         handler = null;

         if (DEBUG) Log.d(TAG, "Destroyed.");
     }

     @Override
     public int onStartCommand(Intent intent, int flags, int serviceId) {
         // TODO: Ensure we're not being called with retry or redeliver.
         // checkArgument(flags == 0);  // retry and redeliver are not supported.

         String jobId = intent.getStringExtra(EXTRA_JOB_ID);
         assert(jobId != null);

         if (DEBUG) Log.d(TAG, "onStartCommand: " + jobId + " with serviceId " + serviceId);

         if (intent.hasExtra(EXTRA_CANCEL)) {
             handleCancel(intent);
         } else {
             FileOperation operation = intent.getParcelableExtra(EXTRA_OPERATION);
             handleOperation(jobId, operation);
         }

         // Track the service supplied id so we can stop the service once we're out of work to do.
         mLastServiceId = serviceId;

         return START_NOT_STICKY;
     }

     private void handleOperation(String jobId, FileOperation operation) {
         synchronized (mJobs) {
             if (mWakeLock == null) {
                 mWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
             }

             if (mJobs.containsKey(jobId)) {
                 Log.w(TAG, "Duplicate job id: " + jobId
                         + ". Ignoring job request for operation: " + operation + ".");
                 return;
             }

             Job job = operation.createJob(this, this, jobId, features);

             if (job == null) {
                 return;
             }

             assert (job != null);
             if (DEBUG) Log.d(TAG, "Scheduling job " + job.id + ".");
             Future<?> future = getExecutorService(operation.getOpType()).submit(job);
             mJobs.put(jobId, new JobRecord(job, future));

             // Acquire wake lock to keep CPU running until we finish all jobs. Acquire wake lock
             // after we create a job and put it in mJobs to avoid potential leaking of wake lock
             // in case where job creation fails.
             mWakeLock.acquire();
         }
     }

     /**
      * Cancels the operation corresponding to job id, identified in "EXTRA_JOB_ID".
      *
      * @param intent The cancellation intent.
      */
     private void handleCancel(Intent intent) {
         assert(intent.hasExtra(EXTRA_CANCEL));
         assert(intent.getStringExtra(EXTRA_JOB_ID) != null);

         String jobId = intent.getStringExtra(EXTRA_JOB_ID);

         if (DEBUG) Log.d(TAG, "handleCancel: " + jobId);

         synchronized (mJobs) {
             // Do nothing if the cancelled ID doesn't match the current job ID. This prevents racey
             // cancellation requests from affecting unrelated copy jobs.  However, if the current job ID
             // is null, the service most likely crashed and was revived by the incoming cancel intent.
             // In that case, always allow the cancellation to proceed.
             JobRecord record = mJobs.get(jobId);
             if (record != null) {
                 record.job.cancel();
                 updateForegroundState(record.job);
             }
         }

         // Dismiss the progress notification here rather than in the copy loop. This preserves
         // interactivity for the user in case the copy loop is stalled.
         // Try to cancel it even if we don't have a job id...in case there is some sad
         // orphan notification.
         notificationManager.cancel(jobId, NOTIFICATION_ID_PROGRESS);

         // TODO: Guarantee the job is being finalized
     }

     private ExecutorService getExecutorService(@OpType int operationType) {
         switch (operationType) {
             case OPERATION_COPY:
             case OPERATION_COMPRESS:
             case OPERATION_EXTRACT:
             case OPERATION_MOVE:
                 return executor;
             case OPERATION_DELETE:
                 return deletionExecutor;
             default:
                 throw new UnsupportedOperationException();
         }
     }

     @GuardedBy("mJobs")
     private void deleteJob(Job job) {
         if (DEBUG) Log.d(TAG, "deleteJob: " + job.id);

         // Release wake lock before clearing jobs just in case we fail to clean them up.
         mWakeLock.release();
         if (!mWakeLock.isHeld()) {
             mWakeLock = null;
         }

         JobRecord record = mJobs.remove(job.id);
         assert(record != null);
         record.job.cleanup();

         // Delay the shutdown until we've cleaned up all notifications. shutdown() is now posted in
         // onFinished(Job job) to main thread.
     }

     /**
      * Most likely shuts down. Won't shut down if service has a pending
      * message. Thread pool is deal with in onDestroy.
      */
     private void shutdown() {
         if (DEBUG) Log.d(TAG, "Shutting down. Last serviceId was " + mLastServiceId);
         assert(mWakeLock == null);

         // Turns out, for us, stopSelfResult always returns false in tests,
         // so we can't guard executor shutdown. For this reason we move
         // executor shutdown to #onDestroy.
         boolean gonnaStop = stopSelfResult(mLastServiceId);
         if (DEBUG) Log.d(TAG, "Stopping service: " + gonnaStop);
         if (!gonnaStop) {
             Log.w(TAG, "Service should be stopping, but reports otherwise.");
         }
     }

     @VisibleForTesting
     boolean holdsWakeLock() {
         return mWakeLock != null && mWakeLock.isHeld();
     }

     @Override
     public void onStart(Job job) {
         if (DEBUG) Log.d(TAG, "onStart: " + job.id);

         Notification notification = job.getSetupNotification();
         // If there is no foreground job yet, set this job to foreground job.
         synchronized (mJobs) {
             if (mForegroundJob == null) {
                 if (DEBUG) Log.d(TAG, "Set foreground job to " + job.id);
                 mForegroundJob = job;
                 foregroundManager.startForeground(NOTIFICATION_ID_PROGRESS, notification);
             } else {
                 // Show start up notification
                 if (DEBUG) Log.d(TAG, "Posting notification for " + job.id);
                 notificationManager.notify(
                         mForegroundJob == job ? null : job.id,
                         NOTIFICATION_ID_PROGRESS,
                         notification);
             }
         }

         // Set up related monitor
         JobMonitor monitor = new JobMonitor(job);
         monitor.start();
     }

     @Override
     public void onFinished(Job job) {
         assert(job.isFinished());
         if (DEBUG) Log.d(TAG, "onFinished: " + job.id);

         synchronized (mJobs) {
             // Delete the job from mJobs first to avoid this job being selected as the foreground
             // task again if we need to swap the foreground job.
             deleteJob(job);

             // Update foreground state before cleaning up notification. If the finishing job is the
             // foreground job, we would need to switch to another one or go to background before
             // we can clean up notifications.
             updateForegroundState(job);

             // Use the same thread of monitors to tackle notifications to avoid race conditions.
             // Otherwise we may fail to dismiss progress notification.
             handler.post(() -> cleanUpNotification(job));

             // Post the shutdown message to main thread after cleanUpNotification() to give it a
             // chance to run. Otherwise this process may be torn down by Android before we've
             // cleaned up the notifications of the last job.
             if (mJobs.isEmpty()) {
                 handler.post(this::shutdown);
             }
         }
     }

     @GuardedBy("mJobs")
     private void updateForegroundState(Job job) {
         Job candidate = getCandidateForegroundJob();

         // If foreground job is retiring and there is still work to do, we need to set it to a new
         // job.
         if (mForegroundJob == job) {
             mForegroundJob = candidate;
             if (candidate == null) {
                 if (DEBUG) Log.d(TAG, "Stop foreground");
                 // Remove the notification here just in case we're torn down before we have the
                 // chance to clean up notifications.
                 foregroundManager.stopForeground(true);
             } else {
                 if (DEBUG) Log.d(TAG, "Switch foreground job to " + candidate.id);

                 notificationManager.cancel(candidate.id, NOTIFICATION_ID_PROGRESS);
                 Notification notification = (candidate.getState() == Job.STATE_STARTED)
                         ? candidate.getSetupNotification()
                         : candidate.getProgressNotification();
                 notificationManager.notify(NOTIFICATION_ID_PROGRESS, notification);
             }
         }
     }

     private void cleanUpNotification(Job job) {

         if (DEBUG) Log.d(TAG, "Canceling notification for " + job.id);
         // Dismiss the ongoing copy notification when the copy is done.
         notificationManager.cancel(job.id, NOTIFICATION_ID_PROGRESS);

         if (job.hasFailures()) {
             if (!job.failedUris.isEmpty()) {
                 Log.e(TAG, "Job failed to resolve uris: " + job.failedUris + ".");
             }
             if (!job.failedDocs.isEmpty()) {
                 Log.e(TAG, "Job failed to process docs: " + job.failedDocs + ".");
             }
             notificationManager.notify(
                     job.id, NOTIFICATION_ID_FAILURE, job.getFailureNotification());
         }

         if (job.hasWarnings()) {
             if (DEBUG) Log.d(TAG, "Job finished with warnings.");
             notificationManager.notify(
                     job.id, NOTIFICATION_ID_WARNING, job.getWarningNotification());
         }
     }

     @GuardedBy("mJobs")
     private Job getCandidateForegroundJob() {
         if (mJobs.isEmpty()) {
             return null;
         }
         for (JobRecord rec : mJobs.values()) {
             if (!rec.job.isFinished()) {
                 return rec.job;
             }
         }
         return null;
     }

     private static final class JobRecord {
         private final Job job;
         private final Future<?> future;

         public JobRecord(Job job, Future<?> future) {
             this.job = job;
             this.future = future;
         }
     }

     /**
      * A class used to periodically polls state of a job.
      *
      * <p>It's possible that jobs hang because underlying document providers stop responding. We
      * still need to update notifications if jobs hang, so instead of jobs pushing their states,
      * we poll states of jobs.
      */
     private final class JobMonitor implements Runnable {
         private static final long PROGRESS_INTERVAL_MILLIS = 500L;

         private final Job mJob;

         private JobMonitor(Job job) {
             mJob = job;
         }

         private void start() {
             handler.post(this);
         }

         @Override
         public void run() {
             synchronized (mJobs) {
                 if (mJob.isFinished()) {
                     // Finish notification is already shown. Progress notification is removed.
                     // Just finish itself.
                     return;
                 }

                 // Only job in set up state has progress bar
                 if (mJob.getState() == Job.STATE_SET_UP) {
                     notificationManager.notify(
                             mForegroundJob == mJob ? null : mJob.id,
                             NOTIFICATION_ID_PROGRESS,
                             mJob.getProgressNotification());
                 }

                 handler.postDelayed(this, PROGRESS_INTERVAL_MILLIS);
             }
         }
     }

     @Override
     public IBinder onBind(Intent intent) {
         return null;  // Boilerplate. See super#onBind
     }

     private static ForegroundManager createForegroundManager(final Service service) {
         return new ForegroundManager() {
             @Override
             public void startForeground(int id, Notification notification) {
                 service.startForeground(id, notification);
             }

             @Override
             public void stopForeground(boolean removeNotification) {
                 service.stopForeground(removeNotification);
             }
         };
     }

     @VisibleForTesting
     interface ForegroundManager {
         void startForeground(int id, Notification notification);
         void stopForeground(boolean removeNotification);
     }
 }
	/*
	* Copyright (C) 2015 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 com.android.documentsui.services;

	import static com.android.documentsui.base.SharedMinimal.DEBUG;

	import android.annotation.IntDef;
	import android.app.Notification;
	import android.app.NotificationChannel;
	import android.app.NotificationManager;
	import android.app.Service;
	import android.content.Intent;
	import android.os.Handler;
	import android.os.IBinder;
	import android.os.PowerManager;
	import android.os.UserManager;
	import android.support.annotation.VisibleForTesting;
	import android.util.Log;

	import com.android.documentsui.R;
	import com.android.documentsui.base.Features;

	import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;
	import java.util.ArrayList;
	import java.util.LinkedHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.concurrent.ExecutorService;
	import java.util.concurrent.Executors;
	import java.util.concurrent.Future;

	import javax.annotation.concurrent.GuardedBy;

	public class FileOperationService extends Service implements Job.Listener {

	public static final String TAG = "FileOperationService";

	// Extra used for OperationDialogFragment, Notifications and picking copy destination.
	public static final String EXTRA_OPERATION_TYPE = "com.android.documentsui.OPERATION_TYPE";

	// Extras used for OperationDialogFragment...
	public static final String EXTRA_DIALOG_TYPE = "com.android.documentsui.DIALOG_TYPE";
	public static final String EXTRA_SRC_LIST = "com.android.documentsui.SRC_LIST";

	public static final String EXTRA_FAILED_URIS = "com.android.documentsui.FAILED_URIS";
	public static final String EXTRA_FAILED_DOCS = "com.android.documentsui.FAILED_DOCS";

	// Extras used to start or cancel a file operation...
	public static final String EXTRA_JOB_ID = "com.android.documentsui.JOB_ID";
	public static final String EXTRA_OPERATION = "com.android.documentsui.OPERATION";
	public static final String EXTRA_CANCEL = "com.android.documentsui.CANCEL";

	@IntDef({
	OPERATION_UNKNOWN,
	OPERATION_COPY,
	OPERATION_COMPRESS,
	OPERATION_EXTRACT,
	OPERATION_MOVE,
	OPERATION_DELETE
	})
	@Retention(RetentionPolicy.SOURCE)
	public @interface OpType {}
	public static final int OPERATION_UNKNOWN = -1;
	public static final int OPERATION_COPY = 1;
	public static final int OPERATION_EXTRACT = 2;
	public static final int OPERATION_COMPRESS = 3;
	public static final int OPERATION_MOVE = 4;
	public static final int OPERATION_DELETE = 5;

	@IntDef({
	MESSAGE_PROGRESS,
	MESSAGE_FINISH
	})
	@Retention(RetentionPolicy.SOURCE)
	public @interface MessageType {}
	public static final int MESSAGE_PROGRESS = 0;
	public static final int MESSAGE_FINISH = 1;

	// TODO: Move it to a shared file when more operations are implemented.
	public static final int FAILURE_COPY = 1;

	static final String NOTIFICATION_CHANNEL_ID = "channel_id";

	private static final int POOL_SIZE = 2; // "pool size", not max "pool size".

	@VisibleForTesting static final int NOTIFICATION_ID_PROGRESS = 1;
	private static final int NOTIFICATION_ID_FAILURE = 2;
	private static final int NOTIFICATION_ID_WARNING = 3;

	// The executor and job factory are visible for testing and non-final
	// so we'll have a way to inject test doubles from the test. It's
	// a sub-optimal arrangement.
	@VisibleForTesting ExecutorService executor;

	// Use a separate thread pool to prioritize deletions.
	@VisibleForTesting ExecutorService deletionExecutor;

	// Use a handler to schedule monitor tasks.
	@VisibleForTesting Handler handler;

	// Use a foreground manager to change foreground state of this service.
	@VisibleForTesting ForegroundManager foregroundManager;

	// Use a notification manager to post and cancel notifications for jobs.
	@VisibleForTesting NotificationManager notificationManager;

	// Use a features to determine if notification channel is enabled.
	@VisibleForTesting Features features;

	@GuardedBy("mJobs")
	private final Map<String, JobRecord> mJobs = new LinkedHashMap<>();

	// The job whose notification is used to keep the service in foreground mode.
	@GuardedBy("mJobs")
	private Job mForegroundJob;

	private PowerManager mPowerManager;
	private PowerManager.WakeLock mWakeLock; // the wake lock, if held.

	private int mLastServiceId;

	@Override
	public void onCreate() {
	// Allow tests to pre-set these with test doubles.
	if (executor == null) {
	executor = Executors.newFixedThreadPool(POOL_SIZE);
	}

	if (deletionExecutor == null) {
	deletionExecutor = Executors.newCachedThreadPool();
	}

	if (handler == null) {
	// Monitor tasks are small enough to schedule them on main thread.
	handler = new Handler();
	}

	if (foregroundManager == null) {
	foregroundManager = createForegroundManager(this);
	}

	if (notificationManager == null) {
	notificationManager = getSystemService(NotificationManager.class);
	}

	features = new Features.RuntimeFeatures(getResources(), UserManager.get(this));
	setUpNotificationChannel();

	if (DEBUG) Log.d(TAG, "Created.");
	mPowerManager = getSystemService(PowerManager.class);
	}

	private void setUpNotificationChannel() {
	if (features.isNotificationChannelEnabled()) {
	NotificationChannel channel = new NotificationChannel(
	NOTIFICATION_CHANNEL_ID,
	getString(R.string.app_label),
	NotificationManager.IMPORTANCE_LOW);
	notificationManager.createNotificationChannel(channel);
	}
	}

	@Override
	public void onDestroy() {
	if (DEBUG) Log.d(TAG, "Shutting down executor.");

	List<Runnable> unfinishedCopies = executor.shutdownNow();
	List<Runnable> unfinishedDeletions = deletionExecutor.shutdownNow();
	List<Runnable> unfinished =
	new ArrayList<>(unfinishedCopies.size() + unfinishedDeletions.size());
	unfinished.addAll(unfinishedCopies);
	unfinished.addAll(unfinishedDeletions);
	if (!unfinished.isEmpty()) {
	Log.w(TAG, "Shutting down, but executor reports running jobs: " + unfinished);
	}

	executor = null;
	deletionExecutor = null;
	handler = null;

	if (DEBUG) Log.d(TAG, "Destroyed.");
	}

	@Override
	public int onStartCommand(Intent intent, int flags, int serviceId) {
	// TODO: Ensure we're not being called with retry or redeliver.
	// checkArgument(flags == 0); // retry and redeliver are not supported.

	String jobId = intent.getStringExtra(EXTRA_JOB_ID);
	assert(jobId != null);

	if (DEBUG) Log.d(TAG, "onStartCommand: " + jobId + " with serviceId " + serviceId);

	if (intent.hasExtra(EXTRA_CANCEL)) {
	handleCancel(intent);
	} else {
	FileOperation operation = intent.getParcelableExtra(EXTRA_OPERATION);
	handleOperation(jobId, operation);
	}

	// Track the service supplied id so we can stop the service once we're out of work to do.
	mLastServiceId = serviceId;

	return START_NOT_STICKY;
	}

	private void handleOperation(String jobId, FileOperation operation) {
	synchronized (mJobs) {
	if (mWakeLock == null) {
	mWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
	}

	if (mJobs.containsKey(jobId)) {
	Log.w(TAG, "Duplicate job id: " + jobId
	+ ". Ignoring job request for operation: " + operation + ".");
	return;
	}

	Job job = operation.createJob(this, this, jobId, features);

	if (job == null) {
	return;
	}

	assert (job != null);
	if (DEBUG) Log.d(TAG, "Scheduling job " + job.id + ".");
	Future<?> future = getExecutorService(operation.getOpType()).submit(job);
	mJobs.put(jobId, new JobRecord(job, future));

	// Acquire wake lock to keep CPU running until we finish all jobs. Acquire wake lock
	// after we create a job and put it in mJobs to avoid potential leaking of wake lock
	// in case where job creation fails.
	mWakeLock.acquire();
	}
	}

	/**
	* Cancels the operation corresponding to job id, identified in "EXTRA_JOB_ID".
	*
	* @param intent The cancellation intent.
	*/
	private void handleCancel(Intent intent) {
	assert(intent.hasExtra(EXTRA_CANCEL));
	assert(intent.getStringExtra(EXTRA_JOB_ID) != null);

	String jobId = intent.getStringExtra(EXTRA_JOB_ID);

	if (DEBUG) Log.d(TAG, "handleCancel: " + jobId);

	synchronized (mJobs) {
	// Do nothing if the cancelled ID doesn't match the current job ID. This prevents racey
	// cancellation requests from affecting unrelated copy jobs. However, if the current job ID
	// is null, the service most likely crashed and was revived by the incoming cancel intent.
	// In that case, always allow the cancellation to proceed.
	JobRecord record = mJobs.get(jobId);
	if (record != null) {
	record.job.cancel();
	updateForegroundState(record.job);
	}
	}

	// Dismiss the progress notification here rather than in the copy loop. This preserves
	// interactivity for the user in case the copy loop is stalled.
	// Try to cancel it even if we don't have a job id...in case there is some sad
	// orphan notification.
	notificationManager.cancel(jobId, NOTIFICATION_ID_PROGRESS);

	// TODO: Guarantee the job is being finalized
	}

	private ExecutorService getExecutorService(@OpType int operationType) {
	switch (operationType) {
	case OPERATION_COPY:
	case OPERATION_COMPRESS:
	case OPERATION_EXTRACT:
	case OPERATION_MOVE:
	return executor;
	case OPERATION_DELETE:
	return deletionExecutor;
	default:
	throw new UnsupportedOperationException();
	}
	}

	@GuardedBy("mJobs")
	private void deleteJob(Job job) {
	if (DEBUG) Log.d(TAG, "deleteJob: " + job.id);

	// Release wake lock before clearing jobs just in case we fail to clean them up.
	mWakeLock.release();
	if (!mWakeLock.isHeld()) {
	mWakeLock = null;
	}

	JobRecord record = mJobs.remove(job.id);
	assert(record != null);
	record.job.cleanup();

	// Delay the shutdown until we've cleaned up all notifications. shutdown() is now posted in
	// onFinished(Job job) to main thread.
	}

	/**
	* Most likely shuts down. Won't shut down if service has a pending
	* message. Thread pool is deal with in onDestroy.
	*/
	private void shutdown() {
	if (DEBUG) Log.d(TAG, "Shutting down. Last serviceId was " + mLastServiceId);
	assert(mWakeLock == null);

	// Turns out, for us, stopSelfResult always returns false in tests,
	// so we can't guard executor shutdown. For this reason we move
	// executor shutdown to #onDestroy.
	boolean gonnaStop = stopSelfResult(mLastServiceId);
	if (DEBUG) Log.d(TAG, "Stopping service: " + gonnaStop);
	if (!gonnaStop) {
	Log.w(TAG, "Service should be stopping, but reports otherwise.");
	}
	}

	@VisibleForTesting
	boolean holdsWakeLock() {
	return mWakeLock != null && mWakeLock.isHeld();
	}

	@Override
	public void onStart(Job job) {
	if (DEBUG) Log.d(TAG, "onStart: " + job.id);

	Notification notification = job.getSetupNotification();
	// If there is no foreground job yet, set this job to foreground job.
	synchronized (mJobs) {
	if (mForegroundJob == null) {
	if (DEBUG) Log.d(TAG, "Set foreground job to " + job.id);
	mForegroundJob = job;
	foregroundManager.startForeground(NOTIFICATION_ID_PROGRESS, notification);
	} else {
	// Show start up notification
	if (DEBUG) Log.d(TAG, "Posting notification for " + job.id);
	notificationManager.notify(
	mForegroundJob == job ? null : job.id,
	NOTIFICATION_ID_PROGRESS,
	notification);
	}
	}

	// Set up related monitor
	JobMonitor monitor = new JobMonitor(job);
	monitor.start();
	}

	@Override
	public void onFinished(Job job) {
	assert(job.isFinished());
	if (DEBUG) Log.d(TAG, "onFinished: " + job.id);

	synchronized (mJobs) {
	// Delete the job from mJobs first to avoid this job being selected as the foreground
	// task again if we need to swap the foreground job.
	deleteJob(job);

	// Update foreground state before cleaning up notification. If the finishing job is the
	// foreground job, we would need to switch to another one or go to background before
	// we can clean up notifications.
	updateForegroundState(job);

	// Use the same thread of monitors to tackle notifications to avoid race conditions.
	// Otherwise we may fail to dismiss progress notification.
	handler.post(() -> cleanUpNotification(job));

	// Post the shutdown message to main thread after cleanUpNotification() to give it a
	// chance to run. Otherwise this process may be torn down by Android before we've
	// cleaned up the notifications of the last job.
	if (mJobs.isEmpty()) {
	handler.post(this::shutdown);
	}
	}
	}

	@GuardedBy("mJobs")
	private void updateForegroundState(Job job) {
	Job candidate = getCandidateForegroundJob();

	// If foreground job is retiring and there is still work to do, we need to set it to a new
	// job.
	if (mForegroundJob == job) {
	mForegroundJob = candidate;
	if (candidate == null) {
	if (DEBUG) Log.d(TAG, "Stop foreground");
	// Remove the notification here just in case we're torn down before we have the
	// chance to clean up notifications.
	foregroundManager.stopForeground(true);
	} else {
	if (DEBUG) Log.d(TAG, "Switch foreground job to " + candidate.id);

	notificationManager.cancel(candidate.id, NOTIFICATION_ID_PROGRESS);
	Notification notification = (candidate.getState() == Job.STATE_STARTED)
	? candidate.getSetupNotification()
	: candidate.getProgressNotification();
	notificationManager.notify(NOTIFICATION_ID_PROGRESS, notification);
	}
	}
	}

	private void cleanUpNotification(Job job) {

	if (DEBUG) Log.d(TAG, "Canceling notification for " + job.id);
	// Dismiss the ongoing copy notification when the copy is done.
	notificationManager.cancel(job.id, NOTIFICATION_ID_PROGRESS);

	if (job.hasFailures()) {
	if (!job.failedUris.isEmpty()) {
	Log.e(TAG, "Job failed to resolve uris: " + job.failedUris + ".");
	}
	if (!job.failedDocs.isEmpty()) {
	Log.e(TAG, "Job failed to process docs: " + job.failedDocs + ".");
	}
	notificationManager.notify(
	job.id, NOTIFICATION_ID_FAILURE, job.getFailureNotification());
	}

	if (job.hasWarnings()) {
	if (DEBUG) Log.d(TAG, "Job finished with warnings.");
	notificationManager.notify(
	job.id, NOTIFICATION_ID_WARNING, job.getWarningNotification());
	}
	}

	@GuardedBy("mJobs")
	private Job getCandidateForegroundJob() {
	if (mJobs.isEmpty()) {
	return null;
	}
	for (JobRecord rec : mJobs.values()) {
	if (!rec.job.isFinished()) {
	return rec.job;
	}
	}
	return null;
	}

	private static final class JobRecord {
	private final Job job;
	private final Future<?> future;

	public JobRecord(Job job, Future<?> future) {
	this.job = job;
	this.future = future;
	}
	}

	/**
	* A class used to periodically polls state of a job.
	*
	* <p>It's possible that jobs hang because underlying document providers stop responding. We
	* still need to update notifications if jobs hang, so instead of jobs pushing their states,
	* we poll states of jobs.
	*/
	private final class JobMonitor implements Runnable {
	private static final long PROGRESS_INTERVAL_MILLIS = 500L;

	private final Job mJob;

	private JobMonitor(Job job) {
	mJob = job;
	}

	private void start() {
	handler.post(this);
	}

	@Override
	public void run() {
	synchronized (mJobs) {
	if (mJob.isFinished()) {
	// Finish notification is already shown. Progress notification is removed.
	// Just finish itself.
	return;
	}

	// Only job in set up state has progress bar
	if (mJob.getState() == Job.STATE_SET_UP) {
	notificationManager.notify(
	mForegroundJob == mJob ? null : mJob.id,
	NOTIFICATION_ID_PROGRESS,
	mJob.getProgressNotification());
	}

	handler.postDelayed(this, PROGRESS_INTERVAL_MILLIS);
	}
	}
	}

	@Override
	public IBinder onBind(Intent intent) {
	return null; // Boilerplate. See super#onBind
	}

	private static ForegroundManager createForegroundManager(final Service service) {
	return new ForegroundManager() {
	@Override
	public void startForeground(int id, Notification notification) {
	service.startForeground(id, notification);
	}

	@Override
	public void stopForeground(boolean removeNotification) {
	service.stopForeground(removeNotification);
	}
	};
	}

	@VisibleForTesting
	interface ForegroundManager {
	void startForeground(int id, Notification notification);
	void stopForeground(boolean removeNotification);
	}
	}