From 8cc0d3ac0f8e7030ff40958ffe63f76087c0c00e Mon Sep 17 00:00:00 2001
From: Fredrik Meringdal <fredrikmeringdal@Fredriks-MacBook-Pro.local>
Date: Mon, 15 Feb 2021 16:12:04 +0100
Subject: infinite loop bug fix

---
 src/rrule_iter.rs | 28 +++++++++++++++-------------
 src/rrulestr.rs   | 14 ++++++++++++++
 2 files changed, 29 insertions(+), 13 deletions(-)

(limited to 'src')

diff --git a/src/rrule_iter.rs b/src/rrule_iter.rs
index d88d034..64bcb5d 100644
--- a/src/rrule_iter.rs
+++ b/src/rrule_iter.rs
@@ -19,16 +19,16 @@ pub struct RRuleIter {
 }
 
 impl RRuleIter {
-    pub fn generate(&mut self) {
+    pub fn generate(&mut self) -> bool {
         let options = self.ii.options.clone();
 
         match options.count {
-            Some(count) if count == 0 => return,
+            Some(count) if count == 0 => return true,
             _ => (),
         };
 
         if self.counter_date.year() > MAX_YEAR {
-            return;
+            return true;
         }
 
         while self.buffer.is_empty() {
@@ -73,7 +73,7 @@ impl RRuleIter {
                             }
                             // This means that the real count is 0, because of the decrement above
                             if count == 1 {
-                                return;
+                                return true;
                             }
                         }
                     }
@@ -98,7 +98,7 @@ impl RRuleIter {
                                 self.timeset[k].second as u32,
                             );
                         if options.until.is_some() && res > options.until.unwrap() {
-                            return;
+                            return true;
                         }
                         if res >= options.dtstart {
                             self.buffer.push_back(res);
@@ -109,7 +109,7 @@ impl RRuleIter {
                                 }
                                 // This means that the real count is 0, because of the decrement above
                                 if count == 1 {
-                                    return;
+                                    return true;
                                 }
                             }
                         }
@@ -118,14 +118,14 @@ impl RRuleIter {
             }
 
             if options.interval == 0 {
-                return;
+                return true;
             }
 
             // Handle frequency and interval
             self.counter_date = increment_counter_date(self.counter_date, &options, filtered);
 
             if self.counter_date.year() > MAX_YEAR {
-                return;
+                return true;
             }
 
             if options.freq == Frequenzy::Hourly
@@ -146,6 +146,8 @@ impl RRuleIter {
 
             self.ii.rebuild(year as isize, month as usize);
         }
+
+        false
     }
 }
 
@@ -153,15 +155,15 @@ impl Iterator for RRuleIter {
     type Item = DateTime<Tz>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        if self.finished {
-            return None;
-        }
-
         if !self.buffer.is_empty() {
             return self.buffer.pop_front();
         }
 
-        self.generate();
+        if self.finished {
+            return None;
+        }
+
+        self.finished = self.generate();
 
         if self.buffer.is_empty() {
             self.finished = true;
diff --git a/src/rrulestr.rs b/src/rrulestr.rs
index 62d1faa..bf616ba 100644
--- a/src/rrulestr.rs
+++ b/src/rrulestr.rs
@@ -748,4 +748,18 @@ mod test {
         assert_eq!(occurences.len(), 7);
         assert!(Utc::now().timestamp() - occurences[0].timestamp() < 2);
     }
+
+    #[test]
+    fn avoids_infinite_loop() {
+        let rrule =
+            "DTSTART:20200427T090000\nFREQ=WEEKLY;UNTIL=20200506T035959Z;BYDAY=FR,MO,TH,TU,WE"
+                .parse::<RRule>()
+                .unwrap();
+        let instances: Vec<_> = rrule
+            .into_iter()
+            .skip_while(|d| *d < Local::now())
+            .take(2)
+            .collect();
+        assert_eq!(instances.len(), 0);
+    }
 }
-- 
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