Support RRULE "COUNT" for recurring events

Summary:
Ref T10747. RRULE events can repeat "UNTIL" a certain time, or a certain "COUNT" of times.

In the UI, we only support "UNTIL". Also support "COUNT".

Test Plan: Imported an event which repeats every other day, 5 times. Got 5 instances.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10747

Differential Revision: https://secure.phabricator.com/D16749

src/applications/calendar/import/PhabricatorCalendarImportEngine.php

@@ -403,6 +403,9 @@ abstract class PhabricatorCalendarImportEngine
         $until_datetime->setViewerTimezone($timezone);
         $event->setUntilDateTime($until_datetime);
       }
+
+      $count = $rrule->getCount();
+      $event->setParameter('recurrenceCount', $count);
     }
 
     return $event;

src/applications/calendar/query/PhabricatorCalendarEventQuery.php

@@ -633,6 +633,11 @@ final class PhabricatorCalendarEventQuery
     PhabricatorCalendarEvent $event,
     $raw_limit) {
 
+    $count = $event->getRecurrenceCount();
+    if ($count && ($count <= $raw_limit)) {
+      return ($count - 1);
+    }
+
     return $raw_limit;
   }
 

src/applications/calendar/storage/PhabricatorCalendarEvent.php

@@ -226,10 +226,16 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
       return null;
     }
 
+    $limit = $sequence + 1;
+    $count = $this->getRecurrenceCount();
+    if ($count && ($count < $limit)) {
+      return null;
+    }
+
     $instances = $set->getEventsBetween(
       null,
       $this->newUntilDateTime(),
-      $sequence + 1);
+      $limit);
 
     return idx($instances, $sequence, null);
   }
@@ -907,9 +913,24 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
       $rrule->setUntil($until);
     }
 
+    $count = $this->getRecurrenceCount();
+    if ($count) {
+      $rrule->setCount($count);
+    }
+
     return $rrule;
   }
 
+  public function getRecurrenceCount() {
+    $count = (int)$this->getParameter('recurrenceCount');
+
+    if (!$count) {
+      return null;
+    }
+
+    return $count;
+  }
+
   public function newRecurrenceSet() {
     if ($this->isChildEvent()) {
       return $this->getParentEvent()->newRecurrenceSet();