Backport of sabre-io/vobject#716 -- support RDATE together with RRULE.

Author: rotdrop

sabre/vobject/lib/Recur/EventIterator.php

@@ -2,6 +2,7 @@
 
 namespace Sabre\VObject\Recur;
 
+use AppendIterator;
 use DateTimeImmutable;
 use DateTimeInterface;
 use DateTimeZone;
@@ -167,18 +168,29 @@ public function __construct($input, $uid = null, ?DateTimeZone $timeZone = null)
             $this->eventDuration = 0;
         }
 
+        $this->recurIterators = [];
+        $isRecurring = false;
+        if (isset($this->masterEvent->RRULE)) {
+            foreach ($this->masterEvent->RRULE as $rRule) {
+                $this->recurIterators[] = new RRuleIterator(
+                    $this->masterEvent->RRULE->getParts(),
+                    $this->startDate
+                );
+            }
+            $isRecurring = true;
+        }
         if (isset($this->masterEvent->RDATE)) {
-            $this->recurIterator = new RDateIterator(
-                $this->masterEvent->RDATE->getParts(),
-                $this->startDate
-            );
-        } elseif (isset($this->masterEvent->RRULE)) {
-            $this->recurIterator = new RRuleIterator(
-                $this->masterEvent->RRULE->getParts(),
-                $this->startDate
-            );
-        } else {
-            $this->recurIterator = new RRuleIterator(
+            foreach ($this->masterEvent->RDATE as $rDate) {
+                $this->recurIterators[] = new RDateIterator(
+                    $rDate->getParts(),
+                    $this->startDate,
+                    omitStart: $isRecurring
+                );
+                $isRecurring = true;
+            }
+        }
+        if (!$isRecurring) {
+            $this->recurIterators[] = new RRuleIterator(
                 [
                     'FREQ' => 'DAILY',
                     'COUNT' => 1,
@@ -317,7 +329,9 @@ public function valid()
     #[\ReturnTypeWillChange]
     public function rewind()
     {
-        $this->recurIterator->rewind();
+        foreach ($this->recurIterators as $iterator) {
+            $iterator->rewind();
+        }
         // re-creating overridden event index.
         $index = [];
         foreach ($this->overriddenEvents as $key => $event) {
@@ -332,6 +346,15 @@ public function rewind()
         $this->nextDate = null;
         $this->currentDate = clone $this->startDate;
 
+        $this->currentCandidates = [];
+        foreach ($this->recurIterators as $index => $iterator) {
+            if (!$iterator->valid()) {
+                continue;
+            }
+            $this->currentCandidates[$index] = $iterator->current()->getTimeStamp();
+        }
+        asort($this->currentCandidates);
+
         $this->next();
     }
 
@@ -354,13 +377,30 @@ public function next()
             // We need to do this until we find a date that's not in the
             // exception list.
             do {
-                if (!$this->recurIterator->valid()) {
+                if (empty($this->currentCandidates)) {
                     $nextDate = null;
                     break;
                 }
-                $nextDate = $this->recurIterator->current();
-                $this->recurIterator->next();
-            } while (isset($this->exceptions[$nextDate->getTimeStamp()]));
+                $nextIndex = array_key_first($this->currentCandidates);
+                $nextDate = $this->recurIterators[$nextIndex]->current();
+                $nextStamp = $this->currentCandidates[$nextIndex];
+
+                // advance all iterators which match the current timestamp
+                foreach ($this->currentCandidates as $index => $stamp) {
+                    if ($stamp > $nextStamp) {
+                        break;
+                    }
+                    $iterator = $this->recurIterators[$index];
+                    $iterator->next();
+                    if ($iterator->valid()) {
+                        $this->currentCandidates[$index] = $iterator->current()->getTimeStamp();
+                        asort($this->currentCandidates);
+                    } else {
+                        unset($this->currentCandidates[$index]);
+                        // resort not neccessary
+                    }
+                }
+            } while (isset($this->exceptions[$nextStamp]));
         }
 
         // $nextDate now contains what rrule thinks is the next one, but an
@@ -408,15 +448,27 @@ public function fastForward(DateTimeInterface $dateTime)
      */
     public function isInfinite()
     {
-        return $this->recurIterator->isInfinite();
+        foreach ($this->recurIterators as $iterator) {
+            if ($iterator->isInfinite()) {
+                return true;
+            }
+        }
+        return false;
     }
 
     /**
-     * RRULE parser.
+     * Array of RRULE parsers.
+     *
+     * @var array<int, RRuleIterator>
+     */
+    protected $recurIterators;
+
+    /**
+     * Array of current candidate timestamps.
      *
-     * @var RRuleIterator
+     * @var array<int, int>
      */
-    protected $recurIterator;
+    protected $currentCandidates;
 
     /**
      * The duration, in seconds, of the master event.

sabre/vobject/lib/Recur/RDateIterator.php

@@ -2,6 +2,7 @@
 
 namespace Sabre\VObject\Recur;
 
+use DateTimeImmutable;
 use DateTimeInterface;
 use Iterator;
 use Sabre\VObject\DateTimeParser;
@@ -26,11 +27,14 @@ class RDateIterator implements Iterator
      *
      * @param string|array $rrule
      */
-    public function __construct($rrule, DateTimeInterface $start)
+    public function __construct($rrule, DateTimeInterface $start, bool $omitStart = false)
     {
         $this->startDate = $start;
         $this->parseRDate($rrule);
-        $this->currentDate = clone $this->startDate;
+        if (!$omitStart) {
+            array_unshift($this->dates, DateTimeImmutable::createFromInterface($this->startDate));
+        }
+        $this->rewind();
     }
 
     /* Implementation of the Iterator interface {{{ */
@@ -39,10 +43,16 @@ public function __construct($rrule, DateTimeInterface $start)
     public function current()
     {
         if (!$this->valid()) {
-            return;
+            return null;
         }
-
-        return clone $this->currentDate;
+        if (is_string($this->dates[$this->counter])) {
+            $this->dates[$this->counter] =
+                DateTimeParser::parse(
+                    $this->dates[$this->counter],
+                    $this->startDate->getTimezone()
+                );
+        }
+        return $this->dates[$this->counter];
     }
 
     /**
@@ -65,7 +75,7 @@ public function key()
     #[\ReturnTypeWillChange]
     public function valid()
     {
-        return $this->counter <= count($this->dates);
+        return $this->counter < count($this->dates);
     }
 
     /**
@@ -76,7 +86,6 @@ public function valid()
     #[\ReturnTypeWillChange]
     public function rewind()
     {
-        $this->currentDate = clone $this->startDate;
         $this->counter = 0;
     }
 
@@ -92,12 +101,6 @@ public function next()
         if (!$this->valid()) {
             return;
         }
-
-        $this->currentDate =
-            DateTimeParser::parse(
-                $this->dates[$this->counter - 1],
-                $this->startDate->getTimezone()
-            );
     }
 
     /* End of Iterator implementation }}} */
@@ -118,7 +121,7 @@ public function isInfinite()
      */
     public function fastForward(DateTimeInterface $dt)
     {
-        while ($this->valid() && $this->currentDate < $dt) {
+        while ($this->valid() && $this->current() < $dt) {
             $this->next();
         }
     }
@@ -132,14 +135,6 @@ public function fastForward(DateTimeInterface $dt)
      */
     protected $startDate;
 
-    /**
-     * The date of the current iteration. You can get this by calling
-     * ->current().
-     *
-     * @var DateTimeInterface
-     */
-    protected $currentDate;
-
     /**
      * The current item in the list.
      *