Add some database checks

app/src/main/java/org/isoron/uhabits/models/CheckmarkList.java

@@ -130,6 +130,8 @@ public abstract class CheckmarkList
      */
     public final int[] getValues(long from, long to)
     {
+        if(from > to) return new int[0];
+
         List<Checkmark> checkmarks = getByInterval(from, to);
         int values[] = new int[checkmarks.size()];
 

app/src/main/java/org/isoron/uhabits/models/sqlite/InconsistentDatabaseException.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2016 Álinson Santos Xavier <isoron@gmail.com>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.uhabits.models.sqlite;
+
+public class InconsistentDatabaseException extends RuntimeException
+{
+    public InconsistentDatabaseException(String message)
+    {
+        super(message);
+    }
+}

app/src/main/java/org/isoron/uhabits/models/sqlite/SQLiteCheckmarkList.java

@@ -28,6 +28,7 @@ import com.activeandroid.query.*;
 
 import org.isoron.uhabits.models.*;
 import org.isoron.uhabits.models.sqlite.records.*;
+import org.isoron.uhabits.utils.*;
 import org.jetbrains.annotations.*;
 
 import java.util.*;
@@ -99,6 +100,15 @@ public class SQLiteCheckmarkList extends CheckmarkList
 
         List<CheckmarkRecord> records = sqlite.query(query, params);
         for (CheckmarkRecord record : records) record.habit = habitRecord;
+
+        int nDays = DateUtils.getDaysBetween(fromTimestamp, toTimestamp) + 1;
+        if (records.size() != nDays)
+        {
+            throw new InconsistentDatabaseException(
+                String.format("habit=%s, %d expected, %d found",
+                    habit.getName(), nDays, records.size()));
+        }
+
         return toCheckmarks(records);
     }