From 3cca785ec21a2a84de125eb35edd3ff99cd0c9c5 Mon Sep 17 00:00:00 2001
From: Sergey Polyakov <sergeuz@gmail.com>
Date: Mon, 2 Jan 2017 00:43:39 +0200
Subject: [PATCH] Register handler for HAL events before app_setup_and_loop()
 is called

---
 system/src/main.cpp | 43 ++++++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/system/src/main.cpp b/system/src/main.cpp
index 516e26d2af..35ef8e5b82 100644
--- a/system/src/main.cpp
+++ b/system/src/main.cpp
@@ -590,22 +590,34 @@ class LEDDeviceKeyStatus: public LEDStatus {
     }
 };
 
-// Callback for HAL events
-void hal_event_handler(int event, int flags, void* data) {
-    switch (event) {
-    case HAL_EVENT_GENERATE_DEVICE_KEY: {
-        static LEDDeviceKeyStatus status(LED_PRIORITY_IMPORTANT);
-        if (flags & HAL_EVENT_FLAG_START) {
-            status.setActive(true);
-        } else if (flags & HAL_EVENT_FLAG_STOP) {
-            status.setActive(false);
-        }
-        break;
+// Handler for HAL events
+class HALEventHandler {
+public:
+    HALEventHandler() {
+        HAL_Set_Event_Callback(handleEvent, nullptr); // Register callback
     }
-    default:
-        break;
+
+private:
+    static void handleEvent(int event, int flags, void* data) {
+        switch (event) {
+        case HAL_EVENT_GENERATE_DEVICE_KEY: {
+            static LEDDeviceKeyStatus status(LED_PRIORITY_IMPORTANT);
+            if (flags & HAL_EVENT_FLAG_START) {
+                status.setActive(true);
+            } else if (flags & HAL_EVENT_FLAG_STOP) {
+                status.setActive(false);
+            }
+            break;
+        }
+        default:
+            break;
+        }
     }
-}
+};
+
+// Certain HAL events can be generated before app_setup_and_loop() is called. Using constructor of a
+// global variable allows to register a handler for HAL events early
+HALEventHandler halEventHandler;
 
 } // namespace
 
@@ -624,9 +636,6 @@ void app_setup_and_loop(void)
     // We have running firmware, otherwise we wouldn't have gotten here
     DECLARE_SYS_HEALTH(ENTERED_Main);
 
-    // Register callback for HAL events
-    HAL_Set_Event_Callback(hal_event_handler, nullptr);
-
     LED_SIGNAL_START(NETWORK_OFF, BACKGROUND);
 
 #if Wiring_Cellular == 1