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Commit ce29e79d authored by Wei Wang's avatar Wei Wang
Browse files

More precise control of batch alarm. 

Use setWindow instead of setRepeating for alarms.
SetRepeating is inexact and the alarm can be triggered quite randomly,
while setWindow gives more precise control of trigger time.

Also unregister alarmReceiver during cleanup to avoid leak of
IntentReceiver.

Bug: 16689485, Bug:16826684
Change-Id: I5245e1424aad3c11ab5ce8a7393031e9d4f1dd03
parent 4f8db63d

android/app/src/com/android/bluetooth/gatt/ScanManager.java

+35 −25
Original line number Diff line number Diff line
@@ -77,6 +77,8 @@ public class ScanManager { 
    private int mLastConfiguredBatchTruncClientIf = Integer.MIN_VALUE;



    private GattService mService;

    private BroadcastReceiver mBatchAlarmReceiver;

    private boolean mBatchAlarmReceiverRegistered;

    private ScanNative mScanNative;

    private ClientHandler mHandler;
@@ -301,8 +303,7 @@ public class ScanManager { 
            mBatchScanIntervalIntent = PendingIntent.getBroadcast(mService, 0, batchIntent, 0);

            IntentFilter filter = new IntentFilter();

            filter.addAction(ACTION_REFRESH_BATCHED_SCAN);

            mService.registerReceiver(

                    new BroadcastReceiver() {

            mBatchAlarmReceiver = new BroadcastReceiver() {

                    @Override

                public void onReceive(Context context, Intent intent) {

                    Log.d(TAG, "awakened up at time " + SystemClock.elapsedRealtime());
@@ -316,7 +317,9 @@ public class ScanManager { 
                        flushBatchScanResults(mBatchClients.iterator().next());

                    }

                }

                    }, filter);

            };

            mService.registerReceiver(mBatchAlarmReceiver, filter);

            mBatchAlarmReceiverRegistered = true;

        }



        private void resetCountDownLatch() {
@@ -426,7 +429,6 @@ public class ScanManager { 
            }

        }





       ScanClient getAggressiveClient(Set<ScanClient> cList, boolean isBatchClientList, int resultType) {

            ScanClient result = null;

            int curScanSetting = Integer.MIN_VALUE;
@@ -497,7 +499,6 @@ public class ScanManager { 
            }

        }





        void startRegularScan(ScanClient client) {

            if (mFilterIndexStack.isEmpty() && isFilteringSupported()) {

                initFilterIndexStack();
@@ -527,15 +528,18 @@ public class ScanManager { 
            setBatchAlarm();

        }



        // Set the batch alarm to be triggered within a short window after batch interval. This

        // allows system to optimize wake up time while still allows a degree of precise control.

        private void setBatchAlarm() {

            if (mBatchClients.isEmpty()) {

            // Cancel any pending alarm just in case.

            mAlarmManager.cancel(mBatchScanIntervalIntent);

                return;

            }

            long batchTriggerIntervalMillis = getBatchTriggerIntervalMillis();

            mAlarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,

                    SystemClock.elapsedRealtime() + batchTriggerIntervalMillis,

                    batchTriggerIntervalMillis,

            // Allows the alarm to be triggered within

            // [batchTriggerIntervalMillis, 1.1 * batchTriggerIntervalMillis]

            long windowLengthMillis = batchTriggerIntervalMillis / 10;

            long windowStartMillis = SystemClock.elapsedRealtime() + batchTriggerIntervalMillis;

            mAlarmManager.setWindow(AlarmManager.ELAPSED_REALTIME_WAKEUP,

                    windowStartMillis, windowLengthMillis,

                    mBatchScanIntervalIntent);

        }
@@ -569,10 +573,16 @@ public class ScanManager { 
            resetCountDownLatch();

            gattClientReadScanReportsNative(client.clientIf, resultType);

            waitForCallback();

            setBatchAlarm();

        }



        void cleanup() {

            mAlarmManager.cancel(mBatchScanIntervalIntent);

            // Protect against multiple calls of cleanup.

            if (mBatchAlarmReceiverRegistered) {

                mService.unregisterReceiver(mBatchAlarmReceiver);

            }

            mBatchAlarmReceiverRegistered = false;

        }



        private long getBatchTriggerIntervalMillis() {