Use g_signal_connect_object() instead of g_signal_connect() in cases where user_data is a GObject.

This ensures that the signal is disconnected if the user_data GObject
is destroyed. I don't think we would encounter that case here, but
it's good practice to do this regardless.

RpGtk.c: For GTK2/GTK3, use g_signal_connect_data() to ensure gfncbdata
is freed, even if the signal isn't called. It usually is, so this is
handling an edge case that probably won't ever happen, but better safe
than sorry. Don't free gfncbdata from within the signal handler.

ConfigDialog.cpp: Use g_clear_signal_handler() instead of g_signal_handler_disconnect().
- Don't use g_signal_connect_object() for this signal.

glib-compat.h: Add g_clear_signal_handler() and G_CONNECT_DEFAULT.

*MenuProvider.c: Use g_signal_connect_data() with a GClosureNotify
function that calls nautilus_file_info_list_free() or equivalent.
Don't free the list from rp_item_convert_to_png() or the ThreadFunc,
since it will be freed by the closure.
- NOTE: get_file_items() uses `transfer none` for the files list,
  so we need to make a deep copy using nautilus_file_info_list_copy().

Reference: https://blogs.gnome.org/mcatanzaro/2022/07/27/common-glib-programming-errors/

Author: GerbilSoft

src/gtk/DragImage.cpp

@@ -210,19 +210,27 @@ rp_drag_image_init(RpDragImage *image)
 #endif /* GTK_CHECK_VERSION(4, 0, 0) */
 
 	// Pixmaps can only be updated once we have a valid size.
-	g_signal_connect(G_OBJECT(image), "map", G_CALLBACK(rp_drag_image_map_signal_handler), nullptr);
-	g_signal_connect(G_OBJECT(image), "notify::width-request",  G_CALLBACK(rp_drag_image_notify_width_or_height_signal_handler), nullptr);
-	g_signal_connect(G_OBJECT(image), "notify::height-request", G_CALLBACK(rp_drag_image_notify_width_or_height_signal_handler), nullptr);
+	g_signal_connect(G_OBJECT(image), "map",
+		G_CALLBACK(rp_drag_image_map_signal_handler), nullptr);
+	g_signal_connect(G_OBJECT(image), "notify::width-request",
+		G_CALLBACK(rp_drag_image_notify_width_or_height_signal_handler), nullptr);
+	g_signal_connect(G_OBJECT(image), "notify::height-request",
+		G_CALLBACK(rp_drag_image_notify_width_or_height_signal_handler), nullptr);
 
 #if GTK_CHECK_VERSION(4, 0, 0)
 	image->dragSource = gtk_drag_source_new();
-	g_signal_connect(G_OBJECT(image->dragSource), "prepare",    G_CALLBACK(rp_drag_image_drag_source_prepare),    image);
-	g_signal_connect(G_OBJECT(image->dragSource), "drag-begin", G_CALLBACK(rp_drag_image_drag_source_drag_begin), image);
-	g_signal_connect(G_OBJECT(image->dragSource), "drag-end",   G_CALLBACK(rp_drag_image_drag_source_drag_end),   image);
+	g_signal_connect_object(G_OBJECT(image->dragSource), "prepare",
+		G_CALLBACK(rp_drag_image_drag_source_prepare), image, G_CONNECT_DEFAULT);
+	g_signal_connect_object(G_OBJECT(image->dragSource), "drag-begin",
+		G_CALLBACK(rp_drag_image_drag_source_drag_begin), image, G_CONNECT_DEFAULT);
+	g_signal_connect_object(G_OBJECT(image->dragSource), "drag-end",
+		G_CALLBACK(rp_drag_image_drag_source_drag_end), image, G_CONNECT_DEFAULT);
 	gtk_widget_add_controller(GTK_WIDGET(image), GTK_EVENT_CONTROLLER(image->dragSource));
 #else /* !GTK_CHECK_VERSION(4, 0, 0) */
-	g_signal_connect(G_OBJECT(image), "drag-begin",    G_CALLBACK(rp_drag_image_drag_begin),    nullptr);
-	g_signal_connect(G_OBJECT(image), "drag-data-get", G_CALLBACK(rp_drag_image_drag_data_get), nullptr);
+	g_signal_connect(G_OBJECT(image), "drag-begin",
+		G_CALLBACK(rp_drag_image_drag_begin), nullptr);
+	g_signal_connect(G_OBJECT(image), "drag-data-get",
+		G_CALLBACK(rp_drag_image_drag_data_get), nullptr);
 #endif /* GTK_CHECK_VERSION(4, 0, 0) */
 }
 
@@ -494,7 +502,7 @@ void rp_drag_image_set_ecks_bawks(RpDragImage *image, bool new_ecks_bawks)
 			fmt::format(FSTR("ecksbawks-{:d}"), i+1).c_str(), nullptr);
 		g_simple_action_set_enabled(action, TRUE);
 		g_object_set_qdata(G_OBJECT(action), ecksbawks_quark, GINT_TO_POINTER(i+1));
-		g_signal_connect(action, "activate", G_CALLBACK(ecksbawks_action_triggered_signal_handler), image);
+		g_signal_connect_object(action, "activate", G_CALLBACK(ecksbawks_action_triggered_signal_handler), image, G_CONNECT_DEFAULT);
 		g_action_map_add_action(G_ACTION_MAP(image->actionGroup), G_ACTION(action));
 		g_menu_append(image->menuEcksBawks, menu_items[i],
 			fmt::format(FSTR("{:s}.ecksbawks-{:d}"), s_prefix, i+1).c_str());
@@ -521,7 +529,8 @@ void rp_drag_image_set_ecks_bawks(RpDragImage *image, bool new_ecks_bawks)
 		GtkWidget *const action = gtk_menu_item_new_with_label(menu_items[i]);
 		gtk_widget_set_name(action, fmt::format(FSTR("menuEcksBawks{:d}"), i).c_str());
 		g_object_set_qdata(G_OBJECT(action), ecksbawks_quark, GINT_TO_POINTER(i+1));
-		g_signal_connect(action, "activate", G_CALLBACK(ecksbawks_menuItem_triggered_signal_handler), image);
+		g_signal_connect_object(action, "activate",
+			G_CALLBACK(ecksbawks_menuItem_triggered_signal_handler), image, G_CONNECT_DEFAULT);
 		gtk_widget_show(action);
 		gtk_menu_shell_append(GTK_MENU_SHELL(image->menuEcksBawks), action);
 	}
@@ -533,7 +542,8 @@ void rp_drag_image_set_ecks_bawks(RpDragImage *image, bool new_ecks_bawks)
 	GtkGesture *const rightClickGesture = gtk_gesture_click_new();
 	gtk_gesture_single_set_button(GTK_GESTURE_SINGLE(rightClickGesture), GDK_BUTTON_SECONDARY);
 	gtk_widget_add_controller(GTK_WIDGET(image), GTK_EVENT_CONTROLLER(rightClickGesture));
-	g_signal_connect(rightClickGesture, "pressed", G_CALLBACK(rp_drag_image_on_gesture_pressed_event), image);
+	g_signal_connect_object(rightClickGesture, "pressed",
+		G_CALLBACK(rp_drag_image_on_gesture_pressed_event), image, G_CONNECT_DEFAULT);
 #else /* !GTK_CHECK_VERSION(4, 0, 0) */
 	// GTK2/GTK3: Show context menu on right-click.
 	// NOTE: On my system, programs show context menus on mouse button down.

src/gtk/LanguageComboBox_gtk3.cpp

@@ -62,7 +62,7 @@ rp_language_combo_box_init_gtkX(struct _RpLanguageComboBox *widget)
 	/** Signals **/
 
 	// Connect the "changed" signal.
-	g_signal_connect(widget->comboBox, "changed", G_CALLBACK(rp_language_combo_box_changed_handler), widget);
+	g_signal_connect_object(widget->comboBox, "changed", G_CALLBACK(rp_language_combo_box_changed_handler), widget, G_CONNECT_DEFAULT);
 }
 
 /**

src/gtk/LanguageComboBox_gtk4.cpp

@@ -188,7 +188,8 @@ rp_language_combo_box_rebuild_icons(struct _RpLanguageComboBox *widget)
 	// GtkDropDown doesn't have a "changed" signal, and its
 	// GtkSelectionModel object isn't accessible.
 	// Listen for GObject::notify for the "selected" property.
-	g_signal_connect(widget->dropDown, "notify::selected", G_CALLBACK(rp_language_combo_box_notify_selected_handler), widget);
+	g_signal_connect_object(widget->dropDown, "notify::selected",
+		G_CALLBACK(rp_language_combo_box_notify_selected_handler), widget, G_CONNECT_DEFAULT);
 }
 
 /** Property accessors / mutators **/

src/gtk/MessageWidget.c

@@ -349,11 +349,11 @@ rp_message_widget_init(RpMessageWidget *widget)
 #  endif /* USE_GTK_REVEALER */
 #endif /* GTK_CHECK_VERSION(4, 0, 0) */
 
-	g_signal_connect(widget->close_button, "clicked",
-		G_CALLBACK(rp_message_widget_close_button_clicked_handler), widget);
+	g_signal_connect_object(widget->close_button, "clicked",
+		G_CALLBACK(rp_message_widget_close_button_clicked_handler), widget, G_CONNECT_DEFAULT);
 #ifdef USE_GTK_REVEALER
-	g_signal_connect(widget->revealer, "notify::child-revealed",
-		G_CALLBACK(rp_message_widget_notify_child_revealed), widget);
+	g_signal_connect_object(widget->revealer, "notify::child-revealed",
+		G_CALLBACK(rp_message_widget_notify_child_revealed), widget, G_CONNECT_DEFAULT);
 #endif /* USE_GTK_REVEALER */
 }
 

src/gtk/OptionsMenuButton.cpp

@@ -245,16 +245,19 @@ rp_options_menu_button_init(RpOptionsMenuButton *widget)
 	// NOTE: GTK4 GtkMenuButton does not have a "clicked" signal.
 	// TODO: Remove the wrapped "clicked" signal?
 #if !GTK_CHECK_VERSION(4, 0, 0)
-	g_signal_connect(widget->menuButton, "clicked", G_CALLBACK(menuButton_clicked_signal_handler), widget);
+	g_signal_connect_object(widget->menuButton, "clicked",
+		G_CALLBACK(menuButton_clicked_signal_handler), widget, G_CONNECT_DEFAULT);
 #endif /* !GTK_CHECK_VERSION(4, 0, 0) */
-	g_signal_connect(widget->menuButton, "activate", G_CALLBACK(menuButton_activate_signal_handler), widget);
+	g_signal_connect_object(widget->menuButton, "activate",
+		G_CALLBACK(menuButton_activate_signal_handler), widget, G_CONNECT_DEFAULT);
 
 #ifndef USE_GTK_MENU_BUTTON
 	// Connect the button's "event" signal.
 	// NOTE: We need to pass the event details. Otherwise, we'll
 	// end up with the menu getting "stuck" to the mouse.
 	// Reference: https://developer.gnome.org/gtk-tutorial/stable/x1577.html
-	g_signal_connect(widget->menuButton, "event", G_CALLBACK(btnOptions_event_signal_handler), widget);
+	g_signal_connect_object(widget->menuButton, "event",
+		G_CALLBACK(btnOptions_event_signal_handler), widget, G_CONNECT_DEFAULT);
 #endif /* !USE_GTK_MENU_BUTTON */
 
 #if USE_G_MENU_MODEL
@@ -553,15 +556,16 @@ rp_options_menu_button_reinit_menu(RpOptionsMenuButton *widget,
 			fmt::to_string(p.id).c_str(), nullptr);
 		g_simple_action_set_enabled(action, TRUE);
 		g_object_set_qdata(G_OBJECT(action), menuOptions_id_quark, GINT_TO_POINTER(p.id));
-		g_signal_connect(action, "activate", G_CALLBACK(action_triggered_signal_handler), widget);
+		g_signal_connect_object(action, "activate",
+			G_CALLBACK(action_triggered_signal_handler), widget, G_CONNECT_DEFAULT);
 		g_action_map_add_action(G_ACTION_MAP(actionGroup), G_ACTION(action));
 
 		// Create the menu item.
 		g_menu_append(menuStdActs, pgettext_expr("RomDataView|Options", p.desc),
 			fmt::format(FSTR("{:s}.{:d}"), s_prefix, p.id).c_str());
 	}
 
-	/** ROM operations. **/
+	/** ROM operations **/
 	const vector<RomData::RomOp> ops = romData->romOps();
 	if (!ops.empty()) {
 		// NOTE: The separator *does* show up properly with the KDE Breeze theme
@@ -576,7 +580,8 @@ rp_options_menu_button_reinit_menu(RpOptionsMenuButton *widget,
 				fmt::to_string(i).c_str(), nullptr);
 			g_simple_action_set_enabled(action, !!(op.flags & RomData::RomOp::ROF_ENABLED));
 			g_object_set_qdata(G_OBJECT(action), menuOptions_id_quark, GINT_TO_POINTER(i));
-			g_signal_connect(action, "activate", G_CALLBACK(action_triggered_signal_handler), widget);
+			g_signal_connect_object(action, "activate",
+				G_CALLBACK(action_triggered_signal_handler), widget, G_CONNECT_DEFAULT);
 			g_action_map_add_action(G_ACTION_MAP(actionGroup), G_ACTION(action));
 
 			// Create the menu item.
@@ -598,7 +603,8 @@ rp_options_menu_button_reinit_menu(RpOptionsMenuButton *widget,
 			pgettext_expr("RomDataView|Options", p.desc));
 		// NOTE: No name for this GtkWidget.
 		g_object_set_qdata(G_OBJECT(menuItem), menuOptions_id_quark, GINT_TO_POINTER(p.id));
-		g_signal_connect(menuItem, "activate", G_CALLBACK(menuOptions_triggered_signal_handler), widget);
+		g_signal_connect_object(menuItem, "activate",
+			G_CALLBACK(menuOptions_triggered_signal_handler), widget, G_CONNECT_DEFAULT);
 		gtk_widget_show(menuItem);
 		gtk_menu_shell_append(GTK_MENU_SHELL(menuOptions), menuItem);
 	}
@@ -622,7 +628,8 @@ rp_options_menu_button_reinit_menu(RpOptionsMenuButton *widget,
 			// NOTE: No name for this GtkWidget.
 			gtk_widget_set_sensitive(menuItem, !!(op.flags & RomData::RomOp::ROF_ENABLED));
 			g_object_set_qdata(G_OBJECT(menuItem), menuOptions_id_quark, GINT_TO_POINTER(i));
-			g_signal_connect(menuItem, "activate", G_CALLBACK(menuOptions_triggered_signal_handler), widget);
+			g_signal_connect_object(menuItem, "activate",
+				G_CALLBACK(menuOptions_triggered_signal_handler), widget, G_CONNECT_DEFAULT);
 			gtk_widget_show(menuItem);
 			gtk_menu_shell_append(GTK_MENU_SHELL(menuOptions), menuItem);
 

src/gtk/RomDataView.cpp

@@ -968,7 +968,8 @@ rp_rom_data_view_init_bitfield(RpRomDataView *page,
 		// NOTE: Unlike Qt, both the "clicked" and "toggled" signals are
 		// emitted for both user and program modifications, so we have to
 		// connect this signal *after* setting the initial value.
-		g_signal_connect(checkBox, "toggled", G_CALLBACK(checkbox_no_toggle_signal_handler), page);
+		g_signal_connect_object(checkBox, "toggled",
+			G_CALLBACK(checkbox_no_toggle_signal_handler), page, G_CONNECT_DEFAULT);
 
 #ifdef USE_GTK_GRID
 		// TODO: GTK_FILL
@@ -1177,7 +1178,8 @@ rp_rom_data_view_update_multi(RpRomDataView *page, uint32_t user_lc)
 		rp_language_combo_box_set_selected_lc(RP_LANGUAGE_COMBO_BOX(page->cboLanguage), lc_to_set);
 
 		// Connect the notification for "selected-lc".
-		g_signal_connect(page->cboLanguage, "notify::selected-lc", G_CALLBACK(cboLanguage_notify_selected_lc_handler), page);
+		g_signal_connect_object(page->cboLanguage, "notify::selected-lc",
+			G_CALLBACK(cboLanguage_notify_selected_lc_handler), page, G_CONNECT_DEFAULT);
 	}
 }
 
@@ -1360,7 +1362,8 @@ rp_rom_data_view_create_options_button(RpRomDataView *page)
 	}
 
 	// Connect the RpOptionsMenuButton's triggered(int) signal.
-	g_signal_connect(page->btnOptions, "triggered", G_CALLBACK(btnOptions_triggered_signal_handler), page);
+	g_signal_connect_object(page->btnOptions, "triggered",
+		G_CALLBACK(btnOptions_triggered_signal_handler), page, G_CONNECT_DEFAULT);
 
 	// Initialize the menu options.
 	rp_options_menu_button_reinit_menu(RP_OPTIONS_MENU_BUTTON(page->btnOptions), page->cxx->romData.get());

src/gtk/RomDataView_gtk3.cpp

@@ -532,7 +532,8 @@ rp_rom_data_view_init_listdata(RpRomDataView *page, const RomFields::Field &fiel
 	// (Windows uses 5.)
 	g_object_set_qdata(G_OBJECT(treeView), RFT_LISTDATA_rows_visible_quark, GINT_TO_POINTER(listDataDesc.rows_visible));
 	if (listDataDesc.rows_visible > 0) {
-		g_signal_connect(treeView, "realize", G_CALLBACK(tree_view_realize_signal_handler), page);
+		g_signal_connect_object(treeView, "realize",
+			G_CALLBACK(tree_view_realize_signal_handler), page, G_CONNECT_DEFAULT);
 	}
 
 	if (isMulti) {

src/gtk/RomDataView_gtk4.cpp

@@ -502,7 +502,8 @@ rp_rom_data_view_init_listdata(RpRomDataView *page, const RomFields::Field &fiel
 	// (Windows uses 5.)
 	g_object_set_qdata(G_OBJECT(treeView), RFT_LISTDATA_rows_visible_quark, GINT_TO_POINTER(listDataDesc.rows_visible));
 	if (listDataDesc.rows_visible > 0) {
-		g_signal_connect(treeView, "realize", G_CALLBACK(tree_view_realize_signal_handler), page);
+		g_signal_connect_object(treeView, "realize",
+			G_CALLBACK(tree_view_realize_signal_handler), page, G_CONNECT_DEFAULT);
 	}
 #endif
 

src/gtk/RpGtk.c

@@ -16,6 +16,9 @@
 // for bool
 #include "stdboolx.h"
 
+// for G_CONNECT_DEFAULT on older glib
+#include "glib-compat.h"
+
 // Use the new GtkFileDialog class on GTK 4.10 and later.
 #if GTK_CHECK_VERSION(4, 9, 1)
 #  define USE_GTK4_FILE_DIALOG 1
@@ -255,6 +258,13 @@ rpGtk_getFileName_fileDialog_response(GtkFileChooserDialog *fileDialog, gint res
 		file = gtk_file_chooser_get_file(GTK_FILE_CHOOSER(fileDialog));
 	}
 
+	// NOTE: gfncbdata is automatically freed by the g_free()
+	// closure specified when calling g_signal_connect_data()
+	// when the fileDialog is deleted.
+	// Copy the required data here.
+	const rpGtk_fileDialogCallback callback = gfncbdata->callback;
+	const gpointer user_data = gfncbdata->user_data;
+
 	// Dialog is no longer needed.
 #if GTK_CHECK_VERSION(4, 0, 0)
 	gtk_window_destroy(GTK_WINDOW(fileDialog));
@@ -264,8 +274,20 @@ rpGtk_getFileName_fileDialog_response(GtkFileChooserDialog *fileDialog, gint res
 
 	// Run the callback.
 	// NOTE: Callback function takes ownership of the GFile.
-	gfncbdata->callback(file, gfncbdata->user_data);
-	g_free(gfncbdata);
+	callback(file, user_data);
+}
+
+/**
+ * GClosureNotify wrapper for g_free, since our compiler warning
+ * settings don't simply allow us to cast g_free to GClosureNotify.
+ * @param ptr
+ * @param closure
+ */
+static void
+rp_GClosureNotify_g_free(gpointer ptr, GClosure *closure)
+{
+	((void)closure);	// RP_UNUSED() is in common.h
+	g_free(ptr);
 }
 #endif /* !USE_GTK4_FILE_DIALOG */
 
@@ -362,6 +384,7 @@ static int rpGtk_getFileName_int(const rpGtk_getFileName_t *gfndata, bool bSave)
 
 	// Prompt for a filename.
 #ifdef USE_GTK4_FILE_DIALOG
+	// GTK4: gfncbdata is freed by rpGtk_getFileName_AsyncReadyCallback().
 	gtk_file_dialog_set_modal(fileDialog, true);
 	if (bSave) {
 		gtk_file_dialog_save(fileDialog, gfndata->parent, NULL,
@@ -371,7 +394,10 @@ static int rpGtk_getFileName_int(const rpGtk_getFileName_t *gfndata, bool bSave)
 			(GAsyncReadyCallback)rpGtk_getFileName_AsyncReadyCallback, gfncbdata);
 	}
 #else /* !USE_GTK4_FILE_DIALOG */
-	g_signal_connect(fileDialog, "response", G_CALLBACK(rpGtk_getFileName_fileDialog_response), gfncbdata);
+	// GTK2/GTK3: Use g_signal_connect_data() to ensure gfncbdata is freed.
+	// It is *not* freed by rpGtk_getFileName_fileDialog_response().
+	g_signal_connect_data(fileDialog, "response",
+		G_CALLBACK(rpGtk_getFileName_fileDialog_response), gfncbdata, rp_GClosureNotify_g_free, G_CONNECT_DEFAULT);
 	gtk_window_set_transient_for(GTK_WINDOW(fileDialog), gfndata->parent);
 	gtk_window_set_modal(GTK_WINDOW(fileDialog), true);
 	gtk_widget_set_visible(GTK_WIDGET(fileDialog), true);

src/gtk/config/AboutTab.cpp

@@ -367,7 +367,7 @@ rp_about_tab_init(RpAboutTab *tab)
 
 	// Connect signals
 #ifdef ENABLE_UPDATE_CHECK
-	g_signal_connect(tab, "realize", G_CALLBACK(rp_about_tab_realize_event), 0);
+	g_signal_connect(tab, "realize", G_CALLBACK(rp_about_tab_realize_event), nullptr);
 #endif /* ENABLE_UPDATE_CHECK */
 }
 
@@ -882,8 +882,10 @@ rp_about_tab_realize_event(GtkWidget	*self,
 	// Run the update checker.
 	if (!tab->updChecker) {
 		tab->updChecker = rp_update_checker_new();
-		g_signal_connect(tab->updChecker, "error", G_CALLBACK(updChecker_error), tab);
-		g_signal_connect(tab->updChecker, "retrieved", G_CALLBACK(updChecker_retrieved), tab);
+		g_signal_connect_object(tab->updChecker, "error",
+			G_CALLBACK(updChecker_error), tab, G_CONNECT_DEFAULT);
+		g_signal_connect_object(tab->updChecker, "retrieved",
+			G_CALLBACK(updChecker_retrieved), tab, G_CONNECT_DEFAULT);
 	}
 	rp_update_checker_run(tab->updChecker);
 }