1 files changed, 14 insertions, 1 deletions
diff --git a/src/kernel/notifications_interface.h b/src/kernel/notifications_interface.h
index e596a144a8..c5e77b0df9 100644
--- a/src/kernel/notifications_interface.h
+++ b/src/kernel/notifications_interface.h
@@ -9,12 +9,25 @@
 
 #include <cstdint>
 #include <string>
+#include <variant>
 
 class CBlockIndex;
 enum class SynchronizationState;
 
 namespace kernel {
 
+//! Result type for use with std::variant to indicate that an operation should be interrupted.
+struct Interrupted{};
+
+//! Simple result type for functions that need to propagate an interrupt status and don't have other return values.
+using InterruptResult = std::variant<std::monostate, Interrupted>;
+
+template <typename T>
+bool IsInterrupted(const T& result)
+{
+    return std::holds_alternative<kernel::Interrupted>(result);
+}
+
 /**
  * A base class defining functions for notifying about certain kernel
  * events.
@@ -24,7 +37,7 @@ class Notifications
 public:
     virtual ~Notifications(){};
 
-    virtual void blockTip(SynchronizationState state, CBlockIndex& index) {}
+    [[nodiscard]] virtual InterruptResult blockTip(SynchronizationState state, CBlockIndex& index) { return {}; }
     virtual void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) {}
     virtual void progress(const bilingual_str& title, int progress_percent, bool resume_possible) {}
     virtual void warning(const bilingual_str& warning) {}