From ff03f3080939eff6b3cc0ab43ca30196b0f89b62 Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Thu, 17 Aug 2023 16:07:09 +0900
Subject: [PATCH] Minor refactoring

Prevent creating a screen-less PendingAction with invalid type.
---
 src/screen.cc | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/screen.cc b/src/screen.cc
index c37ff9d..df17293 100644
--- a/src/screen.cc
+++ b/src/screen.cc
@@ -14,7 +14,21 @@ Screen::Screen(std::weak_ptr<ScreenStack> stack) : stack(stack) {}
 ScreenStack::PendingAction::PendingAction() : screen(), action(Action::NOP) {}
 
 ScreenStack::PendingAction::PendingAction(Action action)
-    : screen(), action(action) {}
+    : screen(), action(action) {
+  switch (action) {
+    case Action::PUSH_SCREEN:
+    case Action::CONSTRUCT_SCREEN:
+      // Cannot push non-existant screen.
+      this->action = Action::NOP;
+#ifndef NDEBUG
+      std::clog << "WARNING: Cannot create PendingAction with PUSH_SCREEN or "
+                   "CONSTRUCT_SCREEN!\n";
+#endif
+      break;
+    default:
+      break;
+  }
+}
 
 ScreenStack::PendingAction::PendingAction(Screen::Ptr &&screen)
     : screen(std::forward<Screen::Ptr>(screen)), action(Action::PUSH_SCREEN) {}