3 files changed, 23 insertions, 4 deletions
diff --git a/src/common/backend.c b/src/common/backend.c
index ad4d908..4c755bd 100644
--- a/src/common/backend.c
+++ b/src/common/backend.c
@@ -1,4 +1,5 @@
 #include "backend.h"
+#include "loop.h"
 
 #include <errno.h>
 #include <stdlib.h>
@@ -369,6 +370,15 @@ yasl_timer_id yasl_surface_add_timer(struct yasl_surface *s, uint64_t interval_n
     yasl_timer_id id = yasl_loop_add_timer(s->display->loop, interval_ns, cb, ud);
     if (!id) return 0;
 
+    /* A one-shot timer retires itself in the loop. Drop retired ids before
+     * the list grows, so the list holds only armed timers. */
+    if (s->timer_count >= s->timer_capacity) {
+        int kept = 0;
+        for (int i = 0; i < s->timer_count; i++)
+            if (yasl_loop_timer_armed(s->display->loop, s->timers[i]))
+                s->timers[kept++] = s->timers[i];
+        s->timer_count = kept;
+    }
     if (s->timer_count >= s->timer_capacity) {
         int new_cap = s->timer_capacity ? s->timer_capacity * 2 : 4;
         yasl_timer_id *nt = realloc(s->timers, (size_t)new_cap * sizeof(*nt));
@@ -388,10 +398,8 @@ bool yasl_surface_del_timer(struct yasl_surface *s, yasl_timer_id id)
     if (!s || id == 0) return false;
     for (int i = 0; i < s->timer_count; i++) {
         if (s->timers[i] == id) {
-            s->timers[i] = 0;
-            if (s->display && s->display->loop)
-                yasl_loop_del_timer(s->display->loop, id);
-            return true;
+            s->timers[i] = s->timers[--s->timer_count];
+            return s->display && yasl_loop_del_timer(s->display->loop, id);
         }
     }
     return false;
diff --git a/src/common/loop.c b/src/common/loop.c
index 3815e91..a63df16 100644
--- a/src/common/loop.c
+++ b/src/common/loop.c
@@ -208,6 +208,15 @@ static void timer_cleanup_deleted(struct yasl_loop *l)
     l->timer_count = dest;
 }
 
+bool yasl_loop_timer_armed(const struct yasl_loop *l, yasl_timer_id id)
+{
+    if (!l || id == 0) return false;
+    for (int i = 0; i < l->timer_count; i++)
+        if (l->timers[i].id == id)
+            return !l->timers[i].deleted;
+    return false;
+}
+
 int yasl_loop_next_timeout_ms(const struct yasl_loop *l)
 {
     if (!l || l->timer_count <= 0) return -1;
diff --git a/src/common/loop.h b/src/common/loop.h
index 579fa2c..663417a 100644
--- a/src/common/loop.h
+++ b/src/common/loop.h
@@ -4,5 +4,7 @@
 #include "yasl/loop.h"
 
 int yasl_loop_next_timeout_ms(const struct yasl_loop *l);
+/* Whether id is armed: added, not deleted, and not retired by its callback. */
+bool yasl_loop_timer_armed(const struct yasl_loop *l, yasl_timer_id id);
 
 #endif /* YASL_COMMON_LOOP_H */