JobScheduler needs to flush queue on charging

Also make it illegal to schedule a job with no constraints.
BUG: 16877705
Change-Id: Iae57286bc4f73163a7e3c9d2d531623fd50f1f72

core/java/android/app/job/JobInfo.java

@@ -434,6 +434,12 @@ public class JobInfo implements Parcelable {
          * @return The job object to hand to the JobScheduler. This object is immutable.
          */
         public JobInfo build() {
+            // Allow tasks with no constraints. What am I, a database?
+            if (!mHasEarlyConstraint && !mHasLateConstraint && !mRequiresCharging &&
+                    !mRequiresDeviceIdle && mNetworkCapabilities == NetworkType.NONE) {
+                throw new IllegalArgumentException("You're trying to build a job with no " +
+                        "constraints, this is not allowed.");
+            }
             mExtras = new PersistableBundle(mExtras);  // Make our own copy.
             // Check that a deadline was not set on a periodic job.
             if (mIsPeriodic && (mMaxExecutionDelayMillis != 0L)) {

core/java/android/app/job/JobScheduler.java

@@ -22,7 +22,13 @@ import android.content.Context;
 
 /**
  * Class for scheduling various types of jobs with the scheduling framework on the device.
- *
+ * See {@link android.app.job.JobInfo} for more description of the types of jobs that can be run
+ * and how to construct them.
+ * The framework will be intelligent about when you receive your callbacks, and attempt to batch
+ * and defer them as much as possible. Typically if you don't specify a deadline on your job, it
+ * can be run at any moment depending on the current state of the JobScheduler's internal queue,
+ * however it might be deferred as long as until the next time the device is connected to a power
+ * source.
  * <p>You do not
  * instantiate this class directly; instead, retrieve it through
  * {@link android.content.Context#getSystemService

services/core/java/com/android/server/job/JobSchedulerService.java

@@ -162,6 +162,7 @@ public class JobSchedulerService extends com.android.server.SystemService
         JobStatus jobStatus = new JobStatus(job, uId);
         cancelJob(uId, job.getId());
         startTrackingJob(jobStatus);
+        mHandler.obtainMessage(MSG_CHECK_JOB).sendToTarget();
         return JobScheduler.RESULT_SUCCESS;
     }
 
@@ -507,7 +508,9 @@ public class JobSchedulerService extends com.android.server.SystemService
                 case MSG_JOB_EXPIRED:
                     synchronized (mJobs) {
                         JobStatus runNow = (JobStatus) message.obj;
-                        if (!mPendingJobs.contains(runNow)) {
+                        // runNow can be null, which is a controller's way of indicating that its
+                        // state is such that all ready jobs should be run immediately.
+                        if (runNow != null && !mPendingJobs.contains(runNow)) {
                             mPendingJobs.add(runNow);
                         }
                     }

services/core/java/com/android/server/job/StateChangedListener.java

@@ -33,7 +33,8 @@ public interface StateChangedListener {
     /**
      * Called by the controller to notify the JobManager that regardless of the state of the task,
      * it must be run immediately.
-     * @param jobStatus The state of the task which is to be run immediately.
+     * @param jobStatus The state of the task which is to be run immediately. <strong>null
+     *                  indicates to the scheduler that any ready jobs should be flushed.</strong>
      */
     public void onRunJobNow(JobStatus jobStatus);
 }

services/core/java/com/android/server/job/controllers/BatteryController.java

@@ -84,15 +84,15 @@ public class BatteryController extends StateController {
 
     @Override
     public void maybeStartTrackingJob(JobStatus taskStatus) {
+        final boolean isOnStablePower = mChargeTracker.isOnStablePower();
         if (taskStatus.hasChargingConstraint()) {
-            final boolean isOnStablePower = mChargeTracker.isOnStablePower();
             synchronized (mTrackedTasks) {
                 mTrackedTasks.add(taskStatus);
                 taskStatus.chargingConstraintSatisfied.set(isOnStablePower);
             }
-            if (isOnStablePower) {
-                mStateChangedListener.onControllerStateChanged();
-            }
+        }
+        if (isOnStablePower) {
+            mChargeTracker.setStableChargingAlarm();
         }
     }
 
@@ -119,9 +119,15 @@ public class BatteryController extends StateController {
                 }
             }
         }
+        // Let the scheduler know that state has changed. This may or may not result in an
+        // execution.
         if (reportChange) {
             mStateChangedListener.onControllerStateChanged();
         }
+        // Also tell the scheduler that any ready jobs should be flushed.
+        if (stablePower) {
+            mStateChangedListener.onRunJobNow(null);
+        }
     }
 
     public class ChargingTracker extends BroadcastReceiver {
@@ -196,9 +202,7 @@ public class BatteryController extends StateController {
                 }
                 // Set up an alarm for ACTION_CHARGING_STABLE - we don't want to kick off tasks
                 // here if the user unplugs the phone immediately.
-                mAlarm.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,
-                        SystemClock.elapsedRealtime() + STABLE_CHARGING_THRESHOLD_MILLIS,
-                        mStableChargingTriggerIntent);
+                setStableChargingAlarm();
                 mCharging = true;
             } else if (Intent.ACTION_POWER_DISCONNECTED.equals(action)) {
                 if (DEBUG) {
@@ -211,7 +215,7 @@ public class BatteryController extends StateController {
             }else if (ACTION_CHARGING_STABLE.equals(action)) {
                 // Here's where we actually do the notify for a task being ready.
                 if (DEBUG) {
-                    Slog.d(TAG, "Battery connected fired @ " + SystemClock.elapsedRealtime()
+                    Slog.d(TAG, "Stable charging fired @ " + SystemClock.elapsedRealtime()
                             + " charging: " + mCharging);
                 }
                 if (mCharging) {  // Should never receive this intent if mCharging is false.
@@ -219,6 +223,17 @@ public class BatteryController extends StateController {
                 }
             }
         }
+
+        void setStableChargingAlarm() {
+            final long alarmTriggerElapsed =
+                    SystemClock.elapsedRealtime() + STABLE_CHARGING_THRESHOLD_MILLIS;
+            if (DEBUG) {
+                Slog.d(TAG, "Setting stable alarm to go off in " +
+                        (STABLE_CHARGING_THRESHOLD_MILLIS / 1000) + "s");
+            }
+            mAlarm.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, alarmTriggerElapsed,
+                    mStableChargingTriggerIntent);
+        }
     }
 
     @Override