From 2069a5a2a0304eda75acc9f0318607aaf46a0825 Mon Sep 17 00:00:00 2001
From: Sam Atkins <atkinssj@serenityos.org>
Date: Thu, 29 Dec 2022 17:31:34 +0000
Subject: [PATCH] Snake: Make initialization from GML fallible

Replace the C_OBJECT factory functions with a custom try_create() which
loads the various bitmaps. Any failures there are now propagated.
---
 Userland/Games/Snake/Game.cpp | 12 ++++++------
 Userland/Games/Snake/Game.h   |  6 ++++--
 Userland/Games/Snake/main.cpp |  2 +-
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Userland/Games/Snake/Game.cpp b/Userland/Games/Snake/Game.cpp
index d3350339e3..e9a36c8673 100644
--- a/Userland/Games/Snake/Game.cpp
+++ b/Userland/Games/Snake/Game.cpp
@@ -19,7 +19,7 @@ REGISTER_WIDGET(Snake, Game);
 
 namespace Snake {
 
-static NonnullRefPtrVector<Gfx::Bitmap> load_food_bitmaps()
+ErrorOr<NonnullRefPtr<Game>> Game::try_create()
 {
     static constexpr auto food_bitmaps_files = Array {
         "/res/emoji/U+1F41F.png"sv,
@@ -54,23 +54,23 @@ static NonnullRefPtrVector<Gfx::Bitmap> load_food_bitmaps()
     };
 
     NonnullRefPtrVector<Gfx::Bitmap> food_bitmaps;
-    food_bitmaps.ensure_capacity(food_bitmaps_files.size());
+    TRY(food_bitmaps.try_ensure_capacity(food_bitmaps_files.size()));
 
     for (auto file : food_bitmaps_files) {
         auto bitmap = Gfx::Bitmap::try_load_from_file(file);
         if (bitmap.is_error()) {
             dbgln("\033[31;1mCould not load bitmap file\033[0m '{}': {}", file, bitmap.error());
-            VERIFY_NOT_REACHED();
+            return bitmap.release_error();
         }
 
         food_bitmaps.unchecked_append(bitmap.release_value());
     }
 
-    return food_bitmaps;
+    return adopt_nonnull_ref_or_enomem(new (nothrow) Game(move(food_bitmaps)));
 }
 
-Game::Game()
-    : m_food_bitmaps(load_food_bitmaps())
+Game::Game(NonnullRefPtrVector<Gfx::Bitmap> food_bitmaps)
+    : m_food_bitmaps(move(food_bitmaps))
 {
     set_font(Gfx::FontDatabase::default_fixed_width_font().bold_variant());
     reset();
diff --git a/Userland/Games/Snake/Game.h b/Userland/Games/Snake/Game.h
index 0c512813b3..5244fadc7c 100644
--- a/Userland/Games/Snake/Game.h
+++ b/Userland/Games/Snake/Game.h
@@ -14,9 +14,11 @@
 namespace Snake {
 
 class Game : public GUI::Frame {
-    C_OBJECT(Game);
+    C_OBJECT_ABSTRACT(Game);
 
 public:
+    static ErrorOr<NonnullRefPtr<Game>> try_create();
+
     virtual ~Game() override = default;
 
     void start();
@@ -28,7 +30,7 @@ public:
     Function<bool(u32)> on_score_update;
 
 private:
-    Game();
+    explicit Game(NonnullRefPtrVector<Gfx::Bitmap> food_bitmaps);
 
     virtual void paint_event(GUI::PaintEvent&) override;
     virtual void keydown_event(GUI::KeyEvent&) override;
diff --git a/Userland/Games/Snake/main.cpp b/Userland/Games/Snake/main.cpp
index c363643e02..ecbdaa08c1 100644
--- a/Userland/Games/Snake/main.cpp
+++ b/Userland/Games/Snake/main.cpp
@@ -49,7 +49,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     window->resize(324, 345);
 
     auto widget = TRY(window->try_set_main_widget<GUI::Widget>());
-    widget->load_from_gml(snake_gml);
+    TRY(widget->try_load_from_gml(snake_gml));
 
     auto& game = *widget->find_descendant_of_type_named<Snake::Game>("game");
     game.set_focus(true);