CSV export: sanitize habit name before creating folder

Fix #113

app/src/main/java/org/isoron/uhabits/io/HabitsCSVExporter.java

@@ -19,6 +19,8 @@
 
 package org.isoron.uhabits.io;
 
+import android.support.annotation.NonNull;
+
 import org.isoron.uhabits.helpers.DateHelper;
 import org.isoron.uhabits.models.CheckmarkList;
 import org.isoron.uhabits.models.Habit;
@@ -64,7 +66,10 @@ public class HabitsCSVExporter
 
         for(Habit h : habits)
         {
-            String habitDirName = String.format("%03d %s/", h.position + 1, h.name);
+            String sane = sanitizeFilename(h.name);
+            String habitDirName = String.format("%03d %s", h.position + 1, sane);
+            habitDirName = habitDirName.trim() + "/";
+
             new File(exportDirName + habitDirName).mkdirs();
             generateDirs.add(habitDirName);
 
@@ -73,6 +78,13 @@ public class HabitsCSVExporter
         }
     }
 
+    @NonNull
+    private String sanitizeFilename(String name)
+    {
+        String s = name.replaceAll("[^a-zA-Z0-9\\._-]+", "");
+        return s.substring(0, Math.min(s.length(), 100));
+    }
+
     private void writeScores(String habitDirName, ScoreList scores) throws IOException
     {
         String path = habitDirName + "Scores.csv";

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

@@ -489,7 +489,7 @@ public class Habit extends Model
      */
     public static void writeCSV(List<Habit> habits, Writer out) throws IOException
     {
-        String header[] = { "Name", "Description", "NumRepetitions", "Interval", "Color" };
+        String header[] = { "Position", "Name", "Description", "NumRepetitions", "Interval", "Color" };
 
         CSVWriter csv = new CSVWriter(out);
         csv.writeNext(header, false);
@@ -498,6 +498,7 @@ public class Habit extends Model
         {
             String[] cols =
             {
+                    String.format("%03d", habit.position + 1),
                     habit.name,
                     habit.description,
                     Integer.toString(habit.freqNum),