initial sabre upgrade (needs lots of work - to wit: authentication, redo the browser interface, and rework event export/import)

vendor/sabre/vobject/lib/Settings.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * This class provides a list of global defaults for vobject.
+ *
+ * Some of these started to appear in various classes, so it made a bit more
+ * sense to centralize them, so it's easier for user to find and change these.
+ *
+ * The global nature of them does mean that changing the settings for one
+ * instance has a global influence.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Settings {
+
+    /**
+     * The minimum date we accept for various calculations with dates, such as
+     * recurrences.
+     *
+     * The choice of 1900 is pretty arbitrary, but it covers most common
+     * use-cases. In particular, it covers birthdates for virtually everyone
+     * alive on earth, which is less than 5 people at the time of writing.
+     */
+    static $minDate = '1900-01-01';
+
+    /**
+     * The maximum date we accept for various calculations with dates, such as
+     * recurrences.
+     *
+     * The choice of 2100 is pretty arbitrary, but should cover most
+     * appointments made for many years to come.
+     */
+    static $maxDate = '2100-01-01';
+
+    /**
+     * The maximum number of recurrences that will be generated.
+     *
+     * This setting limits the maximum of recurring events that this library
+     * generates in its recurrence iterators.
+     *
+     * This is a security measure. Without this, it would be possible to craft
+     * specific events that recur many, many times, potentially DDOSing the
+     * server.
+     *
+     * The default (3500) allows creation of a dialy event that goes on for 10
+     * years, which is hopefully long enough for most.
+     *
+     * Set this value to -1 to disable this control altogether.
+     */
+    static $maxRecurrences = 3500;
+
+}