From f1312fb5c65e62b7121b29bfd74dad470784f497 Mon Sep 17 00:00:00 2001
From: Rune Harlyk <rune@harlyk.dk>
Date: Tue, 8 Jul 2025 15:20:26 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Adds=20hasSubscribers=20function=20?=
 =?UTF-8?q?to=20event=20bus?=
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---
 esp32/include/event_bus.hpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/esp32/include/event_bus.hpp b/esp32/include/event_bus.hpp
index 2de7f4c..6565ce1 100644
--- a/esp32/include/event_bus.hpp
+++ b/esp32/include/event_bus.hpp
@@ -41,6 +41,7 @@ class EventBus {
     inline static portMUX_TYPE mux = portMUX_INITIALIZER_UNLOCKED;
     inline static Msg latest {};
     inline static volatile bool has_latest = false;
+    inline static std::atomic<size_t> sub_cnt {0};
 
     static void store(const Msg& m) {
         portENTER_CRITICAL(&mux);
@@ -119,7 +120,11 @@ class EventBus {
         }
         ~Handle() = default;
         void unsubscribe() {
-            if (index < MaxSubs) subs[index].reset(), index = MaxSubs;
+            if (index < MaxSubs) {
+                subs[index].reset();
+                sub_cnt.fetch_sub(1, std::memory_order_acq_rel);
+                index = MaxSubs;
+            }
         }
         bool valid() const { return index < MaxSubs; }
     };
@@ -134,6 +139,7 @@ class EventBus {
                                      .last = xTaskGetTickCount(),
                                      .mode = mode,
                                      .cnt = 0});
+                sub_cnt.fetch_add(1, std::memory_order_acq_rel);
                 return Handle(i);
             }
         return Handle(MaxSubs);
@@ -200,4 +206,6 @@ class EventBus {
         portEXIT_CRITICAL(&mux);
         return true;
     }
+
+    static bool hasSubscribers() { return sub_cnt.load(std::memory_order_acquire) != 0; }
 };
\ No newline at end of file