LibGUI: Refactor AbstractView "multi select" mode into "selection mode"

There are three possible selection modes for a GUI::AbstractView.

- NoSelection
- SingleSelection
- MultiSelection

We don't enforce these modes fully yet, this patch mostly adds them in
place of the old "multi select" flag.

Libraries/LibGUI/AbstractView.cpp

@@ -403,16 +403,21 @@ void AbstractView::drop_event(DropEvent& event)
         on_drop(index, event);
 }
 
-void AbstractView::set_multi_select(bool multi_select)
+void AbstractView::set_selection_mode(SelectionMode selection_mode)
 {
-    if (m_multi_select == multi_select)
+    if (m_selection_mode == selection_mode)
         return;
-    m_multi_select = multi_select;
-    if (!multi_select && m_selection.size() > 1) {
+    m_selection_mode = selection_mode;
+
+    if (m_selection_mode == SelectionMode::NoSelection)
+        m_selection.clear();
+    else if (m_selection_mode != SelectionMode::SingleSelection && m_selection.size() > 1) {
         auto first_selected = m_selection.first();
         m_selection.clear();
         m_selection.set(first_selected);
     }
+
+    update();
 }
 
 void AbstractView::set_key_column_and_sort_order(int column, SortOrder sort_order)

Libraries/LibGUI/AbstractView.h

@@ -65,6 +65,12 @@ public:
         SelectRows,
     };
 
+    enum class SelectionMode {
+        SingleSelection,
+        MultiSelection,
+        NoSelection,
+    };
+
     virtual void move_cursor(CursorMovement, SelectionUpdate) { }
 
     void set_model(RefPtr<Model>);
@@ -96,8 +102,8 @@ public:
     SelectionBehavior selection_behavior() const { return m_selection_behavior; }
     void set_selection_behavior(SelectionBehavior behavior) { m_selection_behavior = behavior; }
 
-    bool is_multi_select() const { return m_multi_select; }
-    void set_multi_select(bool);
+    SelectionMode selection_mode() const { return m_selection_mode; }
+    void set_selection_mode(SelectionMode);
 
     virtual void model_did_update(unsigned flags) override;
     virtual void did_update_selection();
@@ -197,9 +203,9 @@ private:
     RefPtr<Core::Timer> m_searching_timer;
     ModelIndex m_cursor_index;
     SelectionBehavior m_selection_behavior { SelectionBehavior::SelectItems };
+    SelectionMode m_selection_mode { SelectionMode::SingleSelection };
     unsigned m_edit_triggers { EditTrigger::DoubleClicked | EditTrigger::EditKeyPressed };
     bool m_activates_on_selection { false };
-    bool m_multi_select { true };
     bool m_tab_key_navigation_enabled { false };
     bool m_is_dragging { false };
     bool m_draw_item_text_with_shadow { false };

Libraries/LibGUI/FilePicker.cpp

@@ -123,7 +123,7 @@ FilePicker::FilePicker(Window* parent_window, Mode mode, Options options, const
     m_location_textbox->set_text(path);
 
     m_view = vertical_container.add<MultiView>();
-    m_view->set_multi_select(m_mode == Mode::OpenMultiple);
+    m_view->set_selection_mode(m_mode == Mode::OpenMultiple ? GUI::AbstractView::SelectionMode::MultiSelection : GUI::AbstractView::SelectionMode::SingleSelection);
     m_view->set_model(SortingProxyModel::create(*m_model));
     m_view->set_model_column(FileSystemModel::Column::Name);
     m_view->set_key_column_and_sort_order(GUI::FileSystemModel::Column::Name, GUI::SortOrder::Ascending);

Libraries/LibGUI/IconView.cpp

@@ -247,7 +247,7 @@ void IconView::mousedown_event(MouseEvent& event)
     auto adjusted_position = to_content_position(event.position());
 
     m_might_drag = false;
-    if (is_multi_select()) {
+    if (selection_mode() == SelectionMode::MultiSelection) {
         m_rubber_banding = true;
         m_rubber_band_origin = adjusted_position;
         m_rubber_band_current = adjusted_position;

Libraries/LibGUI/MultiView.cpp

@@ -97,7 +97,6 @@ MultiView::MultiView()
 
     build_actions();
     set_view_mode(ViewMode::Icon);
-    apply_multi_select();
 }
 
 MultiView::~MultiView()
@@ -176,19 +175,16 @@ void MultiView::build_actions()
     m_view_type_action_group->add_action(*m_view_as_columns_action);
 }
 
-void MultiView::apply_multi_select()
+AbstractView::SelectionMode MultiView::selection_mode() const
 {
-    m_table_view->set_multi_select(m_multi_select);
-    m_icon_view->set_multi_select(m_multi_select);
-    m_columns_view->set_multi_select(m_multi_select);
+    return m_table_view->selection_mode();
 }
 
-void MultiView::set_multi_select(bool multi_select)
+void MultiView::set_selection_mode(AbstractView::SelectionMode selection_mode)
 {
-    if (m_multi_select == multi_select)
-        return;
-    m_multi_select = multi_select;
-    apply_multi_select();
+    m_table_view->set_selection_mode(selection_mode);
+    m_icon_view->set_selection_mode(selection_mode);
+    m_columns_view->set_selection_mode(selection_mode);
 }
 
 void MultiView::set_key_column_and_sort_order(int column, SortOrder sort_order)

Libraries/LibGUI/MultiView.h

@@ -97,14 +97,13 @@ public:
     Action& view_as_icons_action() { return *m_view_as_icons_action; }
     Action& view_as_columns_action() { return *m_view_as_columns_action; }
 
-    bool is_multi_select() const { return m_multi_select; }
-    void set_multi_select(bool);
+    AbstractView::SelectionMode selection_mode() const;
+    void set_selection_mode(AbstractView::SelectionMode);
 
 private:
     MultiView();
 
     void build_actions();
-    void apply_multi_select();
 
     ViewMode m_view_mode { Invalid };
     int m_model_column { 0 };
@@ -120,8 +119,6 @@ private:
     RefPtr<Action> m_view_as_columns_action;
 
     OwnPtr<ActionGroup> m_view_type_action_group;
-
-    bool m_multi_select { true };
 };
 
 }