Method ensureExists

app/src/main/java/eu/faircode/email/Helper.java:2876–2887

(Context context, String subdir)

    private static final Map<File, Boolean> exists = new HashMap<>();

    static File ensureExists(Context context, String subdir) {
        File dir = new File(context.getFilesDir(), subdir);
        dir.mkdirs();

        synchronized (exists) {
            if (exists.containsKey(dir))
                return dir;
            exists.put(dir, true);
        }

        return dir;
    }

    static File getExternalFilesDir(Context context) {
        return getExternalFilesDir(context, null);