From 87527179bbdbab1246b7f6a96606b5acffcc60be Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Tue, 5 Sep 2023 14:36:08 +0200
Subject: [PATCH] Allow sorting StateChange callbacks

If the key of the callback is a number, it will be used to invoke
callbacks with the correct ordering.
---
 fairmq/StateMachine.cxx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fairmq/StateMachine.cxx b/fairmq/StateMachine.cxx
index 56668dea..cc2ee6eb 100644
--- a/fairmq/StateMachine.cxx
+++ b/fairmq/StateMachine.cxx
@@ -310,7 +310,9 @@ try {
 
 void StateMachine::SubscribeToStateChange(const string& key, function<void(const State)> callback)
 {
-    static_pointer_cast<FairMQFSM>(fFsm)->fStateChangeSignalsMap.insert({key, static_pointer_cast<FairMQFSM>(fFsm)->fStateChangeSignal.connect(callback)});
+    // Check if the key has a integer value as prefix, if yes, decode it.
+    int i = strtol(key.c_str(), nullptr, 10);
+    static_pointer_cast<FairMQFSM>(fFsm)->fStateChangeSignalsMap.insert({key, static_pointer_cast<FairMQFSM>(fFsm)->fStateChangeSignal.connect(i, callback)});
 }
 
 void StateMachine::UnsubscribeFromStateChange(const string& key)