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1 files changed, 60 insertions, 0 deletions

diff --git a/src/ui/routed_event_dispatch.hpp b/src/ui/routed_event_dispatch.hpp
new file mode 100644
index 00000000..3427441b
--- /dev/null
+++ b/src/ui/routed_event_dispatch.hpp
@@ -0,0 +1,60 @@
+#pragma once
+#include "cru/ui/control.hpp"
+
+namespace cru::ui {
+// Dispatch the event.
+//
+// This will raise routed event of the control and its parent and parent's
+// parent ... (until "last_receiver" if it's not nullptr) with appropriate args.
+//
+// First tunnel from top to bottom possibly stopped by "handled" flag in
+// EventArgs. Second bubble from bottom to top possibly stopped by "handled"
+// flag in EventArgs. Last direct to each control.
+//
+// Args is of type "EventArgs". The first init argument is "sender", which is
+// automatically bound to each receiving control. The second init argument is
+// "original_sender", which is unchanged. And "args" will be perfectly forwarded
+// as the rest arguments.
+template <typename EventArgs, typename... Args>
+void DispatchEvent(Control* const original_sender,
+                   event::RoutedEvent<EventArgs>* (Control::*event_ptr)(),
+                   Control* const last_receiver, Args&&... args) {
+  std::list<Control*> receive_list;
+
+  auto parent = original_sender;
+  while (parent != last_receiver) {
+    receive_list.push_back(parent);
+    parent = parent->GetParent();
+  }
+
+  auto handled = false;
+
+  // tunnel
+  for (auto i = receive_list.crbegin(); i != receive_list.crend(); ++i) {
+    EventArgs event_args(*i, original_sender, std::forward<Args>(args)...);
+    static_cast<Event<EventArgs>*>(((*i)->*event_ptr)()->tunnel.get())
+        ->Raise(event_args);
+    if (event_args.IsHandled()) {
+      handled = true;
+      break;
+    }
+  }
+
+  // bubble
+  if (!handled) {
+    for (auto i : receive_list) {
+      EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
+      static_cast<Event<EventArgs>*>((i->*event_ptr)()->bubble.get())
+          ->Raise(event_args);
+      if (event_args.IsHandled()) break;
+    }
+  }
+
+  // direct
+  for (auto i : receive_list) {
+    EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
+    static_cast<Event<EventArgs>*>((i->*event_ptr)()->direct.get())
+        ->Raise(event_args);
+  }
+}
+}  // namespace cru::ui