fixing RealtimeSleepTimer to work in concurrent threads

src/org/thoughtcrime/securesms/dependencies/ApplicationDependencyProvider.java

@@ -23,13 +23,13 @@
 import org.thoughtcrime.securesms.push.SignalServiceNetworkAccess;
 import org.thoughtcrime.securesms.recipients.LiveRecipientCache;
 import org.thoughtcrime.securesms.service.IncomingMessageObserver;
+import org.thoughtcrime.securesms.util.AlarmSleepTimer;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 import org.whispersystems.libsignal.util.guava.Optional;
 import org.whispersystems.signalservice.api.SignalServiceAccountManager;
 import org.whispersystems.signalservice.api.SignalServiceMessageReceiver;
 import org.whispersystems.signalservice.api.SignalServiceMessageSender;
 import org.whispersystems.signalservice.api.util.CredentialsProvider;
-import org.whispersystems.signalservice.api.util.RealtimeSleepTimer;
 import org.whispersystems.signalservice.api.util.SleepTimer;
 import org.whispersystems.signalservice.api.util.UptimeSleepTimer;
 import org.whispersystems.signalservice.api.websocket.ConnectivityListener;
@@ -70,7 +70,7 @@ public ApplicationDependencyProvider(@NonNull Application context, @NonNull Sign
 
   @Override
   public @NonNull SignalServiceMessageReceiver provideSignalServiceMessageReceiver() {
-    SleepTimer sleepTimer = TextSecurePreferences.isFcmDisabled(context) ? new RealtimeSleepTimer(context)
+    SleepTimer sleepTimer = TextSecurePreferences.isFcmDisabled(context) ? new AlarmSleepTimer(context)
                                                                          : new UptimeSleepTimer();
     return new SignalServiceMessageReceiver(networkAccess.getConfiguration(context),
                                             new DynamicCredentialsProvider(context),

src/org/thoughtcrime/securesms/util/AlarmSleepTimer.java

@@ -0,0 +1,98 @@
+package org.thoughtcrime.securesms.util;
+
+import android.app.AlarmManager;
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Build;
+import android.os.SystemClock;
+import android.util.Log;
+
+import java.util.concurrent.ConcurrentSkipListSet;
+
+import org.whispersystems.signalservice.api.util.SleepTimer;
+
+/**
+ * A sleep timer that is based on elapsed realtime, so
+ * that it works properly, even in low-power sleep modes.
+ *
+ */
+public class AlarmSleepTimer implements SleepTimer {
+  private static final String TAG = AlarmSleepTimer.class.getSimpleName();
+  private static ConcurrentSkipListSet<Integer> actionIdList = new ConcurrentSkipListSet<>();
+
+  private final Context context;
+
+  public AlarmSleepTimer(Context context) {
+    this.context = context;
+  }
+
+  @Override
+  public void sleep(long millis) {
+    final AlarmReceiver alarmReceiver = new AlarmSleepTimer.AlarmReceiver();
+    int actionId = 0;
+    while (!actionIdList.add(actionId)){
+      actionId++;
+    }
+    try {
+      context.registerReceiver(alarmReceiver,
+             new IntentFilter(AlarmReceiver.WAKE_UP_THREAD_ACTION + "." + actionId));
+
+      final long startTime = System.currentTimeMillis();
+      alarmReceiver.setAlarm(millis, AlarmReceiver.WAKE_UP_THREAD_ACTION + "." + actionId);
+
+      while (System.currentTimeMillis() - startTime < millis) {
+        try {
+          synchronized (this) {
+            wait(millis - System.currentTimeMillis() + startTime);
+          }
+        } catch (InterruptedException e) {
+          Log.w(TAG, e);
+        }
+      }
+      context.unregisterReceiver(alarmReceiver);
+    } catch(Exception e) {
+      Log.w(TAG, "Exception during sleep ...",e);
+    }finally {
+      actionIdList.remove(actionId);
+    }
+  }
+
+  private class AlarmReceiver extends BroadcastReceiver {
+    private static final String WAKE_UP_THREAD_ACTION = "org.thoughtcrime.securesms.util.AlarmSleepTimer.AlarmReceiver.WAKE_UP_THREAD";
+
+    private void setAlarm(long millis, String action) {
+      final Intent        intent        = new Intent(action);
+      final PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
+      final AlarmManager  alarmManager  = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
+
+      Log.w(TAG, "Setting alarm to wake up in " + millis + "ms.");
+
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+        alarmManager.setExactAndAllowWhileIdle(AlarmManager.ELAPSED_REALTIME_WAKEUP,
+                                               SystemClock.elapsedRealtime() + millis,
+                                               pendingIntent);
+      } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+        alarmManager.setExact(AlarmManager.ELAPSED_REALTIME_WAKEUP,
+                              SystemClock.elapsedRealtime() + millis,
+                              pendingIntent);
+      } else {
+        alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,
+                         SystemClock.elapsedRealtime() + millis,
+                         pendingIntent);
+      }
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+      Log.w(TAG, "Waking up.");
+
+      synchronized (AlarmSleepTimer.this) {
+        AlarmSleepTimer.this.notifyAll();
+      }
+    }
+  }
+}
+