-frontend: Fixed crashes switching between favourites and other filters.

* Also made the system and software selection menus a bit less eager to
  reselect the first item.

-docs: Bumped documentation version to 0.238.

docs/source/conf.py

@@ -56,16 +56,16 @@ master_doc = 'index'
 
 # General information about the project.
 project = u'MAME Documentation'
-copyright = u'2021, MAMEdev Team'
+copyright = u'1997-2021, MAMEdev and contributors'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = '0.237'
+version = '0.238'
 # The full version, including alpha/beta/rc tags.
-release = '0.237'
+release = '0.238'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.

src/frontend/mame/ui/selgame.cpp

@@ -341,6 +341,8 @@ void menu_select_game::populate(float &customtop, float &custombottom)
 
 	if (!isfavorite())
 	{
+		if (m_populated_favorites)
+			m_prev_selected = nullptr;
 		m_populated_favorites = false;
 		m_displaylist.clear();
 		machine_filter const *const flt(m_persistent_data.filter_data().get_current_filter());
@@ -399,6 +401,8 @@ void menu_select_game::populate(float &customtop, float &custombottom)
 	else
 	{
 		// populate favorites list
+		if (!m_populated_favorites)
+			m_prev_selected = nullptr;
 		m_populated_favorites = true;
 		m_search.clear();
 		mame_machine_manager::instance()->favorite().apply_sorted(
@@ -412,8 +416,8 @@ void menu_select_game::populate(float &customtop, float &custombottom)
 						bool cloneof = strcmp(info.driver->parent, "0");
 						if (cloneof)
 						{
-							int cx = driver_list::find(info.driver->parent);
-							if (cx != -1 && ((driver_list::driver(cx).flags & machine_flags::IS_BIOS_ROOT) != 0))
+							int const cx = driver_list::find(info.driver->parent);
+							if ((0 <= cx) && ((driver_list::driver(cx).flags & machine_flags::IS_BIOS_ROOT) != 0))
 								cloneof = false;
 						}
 
@@ -1036,7 +1040,7 @@ void menu_select_game::get_selection(ui_software_info const *&software, ui_syste
 	if (m_populated_favorites)
 	{
 		software = reinterpret_cast<ui_software_info const *>(get_selection_ptr());
-		system = &m_persistent_data.systems()[driver_list::find(software->driver->name)];
+		system = software ? &m_persistent_data.systems()[driver_list::find(software->driver->name)] : nullptr;
 	}
 	else
 	{
@@ -1100,7 +1104,7 @@ void menu_select_game::filter_selected()
 						}
 					}
 					m_persistent_data.filter_data().set_current_filter_type(new_type);
-					reset(reset_options::SELECT_FIRST);
+					reset(reset_options::REMEMBER_REF);
 				});
 	}
 }

src/frontend/mame/ui/selmenu.cpp

@@ -1419,7 +1419,6 @@ void menu_select_launch::handle_keys(uint32_t flags, int &iptkey)
 		}
 		else if (m_focus == focused_menu::LEFT)
 		{
-			m_prev_selected = nullptr;
 			filter_selected();
 		}
 		return;
@@ -1774,7 +1773,6 @@ void menu_select_launch::handle_events(uint32_t flags, event &ev)
 				}
 				else if (hover() >= HOVER_FILTER_FIRST && hover() <= HOVER_FILTER_LAST)
 				{
-					m_prev_selected = nullptr;
 					m_filter_highlight = hover() - HOVER_FILTER_FIRST;
 					filter_selected();
 					stop = true;
@@ -1953,18 +1951,29 @@ void menu_select_launch::draw(uint32_t flags)
 	// make sure the selection
 	if (m_available_items < m_visible_lines)
 		m_visible_lines = m_available_items;
-	if (top_line < 0 || is_first_selected())
+	int selection;
+	if (selected_index() < m_available_items)
+	{
+		selection = selected_index();
+	}
+	else
+	{
+		selection = 0;
+		while ((m_available_items > selection) && (item(selection).ref() != m_prev_selected))
+			++selection;
+	}
+	if (top_line < 0 || !selection)
 	{
 		top_line = 0;
 	}
-	else if (selected_index() < m_available_items)
+	else if (selection < m_available_items)
 	{
-		if (selected_index() >= (top_line + m_visible_lines))
-			top_line = selected_index() - (m_visible_lines / 2);
+		if ((selection >= (top_line + m_visible_lines)) || (selection <= top_line))
+			top_line = (std::max)(selection - (m_visible_lines / 2), 0);
 		if ((top_line + m_visible_lines) >= m_available_items)
 			top_line = m_available_items - m_visible_lines;
-		else if (selected_index() >= (top_line + m_visible_lines - 2))
-			top_line = selected_index() - m_visible_lines + ((selected_index() == (m_available_items - 1)) ? 1: 2);
+		else if (selection >= (top_line + m_visible_lines - 2))
+			top_line = selection - m_visible_lines + ((selection == (m_available_items - 1)) ? 1: 2);
 	}
 
 	// determine effective positions taking into account the hilighting arrows

src/frontend/mame/ui/selsoft.cpp

@@ -741,7 +741,7 @@ void menu_select_software::filter_selected()
 						}
 					}
 					m_data->set_filter_type(new_type);
-					reset(reset_options::SELECT_FIRST);
+					reset(reset_options::REMEMBER_REF);
 				});
 	}
 }