From 293790bb9336961a5c7b0e38fd9f254146eee8d0 Mon Sep 17 00:00:00 2001
From: Pierre Tachoire <pierre@lightpanda.io>
Date: Wed, 17 Apr 2024 15:51:06 +0200
Subject: [PATCH] handle listeners events removing themselves

---
 src/events/event_target.c | 10 +++++++++-
 src/utils/list.h          | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/events/event_target.c b/src/events/event_target.c
index f05affde..67a4d134 100644
--- a/src/events/event_target.c
+++ b/src/events/event_target.c
@@ -241,9 +241,17 @@ dom_exception _dom_event_target_dispatch(dom_event_target *et,
 					 * break */
 					if (evt->stop_now == true)
 						break;
+
+					// A listener can modify the event target listeners list
+					// during the loop. At this stage, `le` can be removed from
+					// the list and its memory freed.
+					// First we need to detect if `le` still exists.
+					if (!list_has((struct list_entry *)eti->listeners, (struct list_entry *)le)) {
+						// `le` has been deleted.
+						break;
+					}
 				}
 			}
-
 			le = (struct listener_entry *) le->list.next;
 		} while (le != eti->listeners);
 	}
diff --git a/src/utils/list.h b/src/utils/list.h
index 6e3ba209..ba973f21 100644
--- a/src/utils/list.h
+++ b/src/utils/list.h
@@ -13,6 +13,7 @@
 #define dom_utils_list_h_
 
 #include <stddef.h>
+#include <stdbool.h>
 
 struct list_entry {
 	struct list_entry *prev;
@@ -58,4 +59,21 @@ static inline void list_del(struct list_entry *ent)
 	ent->next = ent;
 }
 
+/**
+ * Detect if an entry is in the list
+ *
+ * \param entry  The entry need to be deleted from the list
+ */
+static inline bool list_has(struct list_entry *head, struct list_entry *ent)
+{
+	struct list_entry *cur = head;
+	do {
+		if (cur == ent) {
+			return true;
+		}
+		cur = cur->next;
+	} while (cur != head);
+	return false;
+}
+
 #endif