Make it possible to sort a GTableModel by column+order.

This is accomplished by putting a GSortingProxyTableModel between the model
and the view. It's pretty simplistic but it works for this use case. :^)

Applications/ProcessManager/ProcessTableModel.cpp

@@ -3,19 +3,6 @@
 #include <stdio.h>
 #include <pwd.h>
 
-enum Column {
-    Icon = 0,
-    Name,
-    CPU,
-    State,
-    Priority,
-    User,
-    PID,
-    Linear,
-    Physical,
-    __Count
-};
-
 ProcessTableModel::ProcessTableModel()
 {
     setpwent();

Applications/ProcessManager/ProcessTableModel.h

@@ -8,6 +8,19 @@
 
 class ProcessTableModel final : public GTableModel {
 public:
+    enum Column {
+        Icon = 0,
+        Name,
+        CPU,
+        State,
+        Priority,
+        User,
+        PID,
+        Linear,
+        Physical,
+        __Count
+    };
+
     ProcessTableModel();
     virtual ~ProcessTableModel() override;
 

Applications/ProcessManager/ProcessTableView.cpp

@@ -1,11 +1,15 @@
 #include "ProcessTableView.h"
 #include "ProcessTableModel.h"
-
+#include <LibGUI/GSortingProxyTableModel.h>
+#include <stdio.h>
 
 ProcessTableView::ProcessTableView(GWidget* parent)
     : GTableView(parent)
 {
-    set_model(make<ProcessTableModel>());
+    auto process_model = make<ProcessTableModel>();
+    m_model = process_model.ptr();
+    set_model(make<GSortingProxyTableModel>(move(process_model)));
+    GTableView::model()->set_key_column_and_sort_order(ProcessTableModel::Column::CPU, GSortOrder::Descending);
     start_timer(1000);
     model().update();
 }
@@ -32,13 +36,3 @@ pid_t ProcessTableView::selected_pid() const
 {
     return model().selected_pid();
 }
-
-inline ProcessTableModel& ProcessTableView::model()
-{
-    return static_cast<ProcessTableModel&>(*GTableView::model());
-}
-
-inline const ProcessTableModel& ProcessTableView::model() const
-{
-    return static_cast<const ProcessTableModel&>(*GTableView::model());
-}

Applications/ProcessManager/ProcessTableView.h

@@ -21,7 +21,9 @@ protected:
 private:
     virtual void timer_event(GTimerEvent&) override;
 
-    ProcessTableModel& model();
-    const ProcessTableModel& model() const;
+    ProcessTableModel& model() { return *m_model; }
+    const ProcessTableModel& model() const { return *m_model; }
+
+    ProcessTableModel* m_model { nullptr };
 };