From abfddd01d406df763a110a14cfd84eb069cd2125 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?kleines=20Filmr=C3=B6llchen?= <filmroellchen@serenityos.org>
Date: Sat, 19 Mar 2022 00:19:56 +0100
Subject: [PATCH] SystemMonitor: Register MemoryStatsWidget

This also requires that the associated graph widget may be null.
---
 .../SystemMonitor/MemoryStatsWidget.cpp       | 24 ++++++++++++++++---
 .../SystemMonitor/MemoryStatsWidget.h         | 11 ++++++---
 Userland/Applications/SystemMonitor/main.cpp  |  4 ++--
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/Userland/Applications/SystemMonitor/MemoryStatsWidget.cpp b/Userland/Applications/SystemMonitor/MemoryStatsWidget.cpp
index 30d2505d87c..22678d23a4b 100644
--- a/Userland/Applications/SystemMonitor/MemoryStatsWidget.cpp
+++ b/Userland/Applications/SystemMonitor/MemoryStatsWidget.cpp
@@ -17,6 +17,10 @@
 #include <LibGfx/StylePainter.h>
 #include <stdlib.h>
 
+REGISTER_WIDGET(SystemMonitor, MemoryStatsWidget)
+
+namespace SystemMonitor {
+
 static MemoryStatsWidget* s_the;
 
 MemoryStatsWidget* MemoryStatsWidget::the()
@@ -24,7 +28,12 @@ MemoryStatsWidget* MemoryStatsWidget::the()
     return s_the;
 }
 
-MemoryStatsWidget::MemoryStatsWidget(SystemMonitor::GraphWidget& graph)
+MemoryStatsWidget::MemoryStatsWidget()
+    : MemoryStatsWidget(nullptr)
+{
+}
+
+MemoryStatsWidget::MemoryStatsWidget(GraphWidget* graph)
     : m_graph(graph)
 {
     VERIFY(!s_the);
@@ -59,6 +68,11 @@ MemoryStatsWidget::MemoryStatsWidget(SystemMonitor::GraphWidget& graph)
     refresh();
 }
 
+void MemoryStatsWidget::set_graph_widget(GraphWidget& graph)
+{
+    m_graph = &graph;
+}
+
 static inline u64 page_count_to_bytes(size_t count)
 {
     return count * 4096;
@@ -101,6 +115,10 @@ void MemoryStatsWidget::refresh()
     m_kfree_count_label->set_text(String::formatted("{}", kfree_call_count));
     m_kmalloc_difference_label->set_text(String::formatted("{:+}", kmalloc_call_count - kfree_call_count));
 
-    m_graph.set_max(page_count_to_bytes(total_userphysical_and_swappable_pages) + kmalloc_bytes_total);
-    m_graph.add_value({ page_count_to_bytes(user_physical_committed), page_count_to_bytes(user_physical_allocated), kmalloc_bytes_total });
+    if (m_graph) {
+        m_graph->set_max(page_count_to_bytes(total_userphysical_and_swappable_pages) + kmalloc_bytes_total);
+        m_graph->add_value({ page_count_to_bytes(user_physical_committed), page_count_to_bytes(user_physical_allocated), kmalloc_bytes_total });
+    }
+}
+
 }
diff --git a/Userland/Applications/SystemMonitor/MemoryStatsWidget.h b/Userland/Applications/SystemMonitor/MemoryStatsWidget.h
index efe972e9a33..f0c005a8e1b 100644
--- a/Userland/Applications/SystemMonitor/MemoryStatsWidget.h
+++ b/Userland/Applications/SystemMonitor/MemoryStatsWidget.h
@@ -10,8 +10,8 @@
 #include <LibGUI/Widget.h>
 
 namespace SystemMonitor {
+
 class GraphWidget;
-}
 
 class MemoryStatsWidget final : public GUI::Widget {
     C_OBJECT(MemoryStatsWidget)
@@ -20,12 +20,15 @@ public:
 
     virtual ~MemoryStatsWidget() override = default;
 
+    void set_graph_widget(GraphWidget& graph);
+
     void refresh();
 
 private:
-    MemoryStatsWidget(SystemMonitor::GraphWidget& graph);
+    MemoryStatsWidget(GraphWidget* graph);
+    MemoryStatsWidget();
 
-    SystemMonitor::GraphWidget& m_graph;
+    GraphWidget* m_graph;
     RefPtr<GUI::Label> m_user_physical_pages_label;
     RefPtr<GUI::Label> m_user_physical_pages_committed_label;
     RefPtr<GUI::Label> m_supervisor_physical_pages_label;
@@ -34,3 +37,5 @@ private:
     RefPtr<GUI::Label> m_kfree_count_label;
     RefPtr<GUI::Label> m_kmalloc_difference_label;
 };
+
+}
diff --git a/Userland/Applications/SystemMonitor/main.cpp b/Userland/Applications/SystemMonitor/main.cpp
index 4e8976b33d7..db30e4688d5 100644
--- a/Userland/Applications/SystemMonitor/main.cpp
+++ b/Userland/Applications/SystemMonitor/main.cpp
@@ -212,7 +212,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto& refresh_timer = window->add<Core::Timer>(
         frequency * 1000, [&] {
             process_model->update();
-            if (auto* memory_stats_widget = MemoryStatsWidget::the())
+            if (auto* memory_stats_widget = SystemMonitor::MemoryStatsWidget::the())
                 memory_stats_widget->refresh();
         });
 
@@ -746,6 +746,6 @@ NonnullRefPtr<GUI::Widget> build_performance_tab()
                                          },
                                      });
 
-    graphs_container->add<MemoryStatsWidget>(memory_graph);
+    graphs_container->add<SystemMonitor::MemoryStatsWidget>(&memory_graph);
     return graphs_container;
 }