GTK: revised the key processing again to prevent crashes

* Processing a queued list of key events with an idle timer turned out
  to be tricky.
  Since teco_interface_pop_key_idle_cb() would eventually drive the main
  loop with gtk_main_iteration_do() which may result in a recursive
  invocation of teco_interface_pop_key_idle_cb() which will eventually crash.
* We'd have to mask the idle watcher during the execution time of teco_interface_pop_key_idle_cb().
* Therefore it has been decided to use a tight loop again to process the
  event queue.
  After thawing the window, we now manually drive the event loop with gtk_main_iteration_do()
  to make sure that the UI is updated.
  This could result in a recursive invocation of teco_interface_key_pressed_cb() of course but
  the callback is already secured against this.

1 files changed, 35 insertions, 41 deletions

diff --git a/src/interface-gtk/interface.c b/src/interface-gtk/interface.c
index edac479..58656b8 100644
--- a/src/interface-gtk/interface.c
+++ b/src/interface-gtk/interface.c
@@ -1097,39 +1097,6 @@ teco_interface_cmdline_size_allocate_cb(GtkWidget *widget,
 }
 
 static gboolean
-teco_interface_pop_key_idle_cb(gpointer user_data)
-{
-	g_autoptr(GError) error = NULL;
-
-	/*
-	 * Avoid redraws of the current view by freezing updates
-	 * on the view's GDK window (we're running in parallel
-	 * to the main loop so there could be frequent redraws).
-	 * By freezing updates, the behaviour is similar to
-	 * the Curses UI.
-	 */
-	GdkWindow *top_window = gdk_window_get_toplevel(gtk_widget_get_window(teco_interface.window));
-	gdk_window_freeze_updates(top_window);
-
-	/*
-	 * The event queue might be filled when pressing keys when SciTECO
-	 * is busy executing code.
-	 */
-	g_autoptr(GdkEvent) event = g_queue_pop_head(teco_interface.event_queue);
-
-	teco_sigint_occurred = FALSE;
-	teco_interface_handle_key_press(event->key.keyval, event->key.state, &error);
-	teco_sigint_occurred = FALSE;
-
-	if (g_error_matches(error, TECO_ERROR, TECO_ERROR_QUIT))
-		gtk_main_quit();
-
-	gdk_window_thaw_updates(top_window);
-
-	return !g_queue_is_empty(teco_interface.event_queue);
-}
-
-static gboolean
 teco_interface_key_pressed_cb(GtkWidget *widget, GdkEventKey *event, gpointer user_data)
 {
 	g_autoptr(GError) error = NULL;
@@ -1169,14 +1136,41 @@ teco_interface_key_pressed_cb(GtkWidget *widget, GdkEventKey *event, gpointer us
 
 	g_queue_push_tail(teco_interface.event_queue, gdk_event_copy((GdkEvent *)event));
 
-	/*
-	 * This should give the UI a chance to update after every keypress.
-	 * If we would empty the event_queue in a tight loop, then keeping
-	 * a key pressed could result in the UI beeing frozen until the
-	 * key is eventually released.
-	 */
-	if (teco_interface_pop_key_idle_cb(NULL) == G_SOURCE_CONTINUE)
-		g_idle_add_full(G_PRIORITY_DEFAULT_IDLE, teco_interface_pop_key_idle_cb, NULL, NULL);
+	GdkWindow *top_window = gdk_window_get_toplevel(gtk_widget_get_window(teco_interface.window));
+
+	do {
+		/*
+		 * The event queue might be filled when pressing keys when SciTECO
+		 * is busy executing code.
+		 */
+		g_autoptr(GdkEvent) event = g_queue_pop_head(teco_interface.event_queue);
+
+		/*
+		 * Avoid redraws of the current view by freezing updates
+		 * on the view's GDK window (we're running in parallel
+		 * to the main loop so there could be frequent redraws).
+		 * By freezing updates, the behaviour is similar to
+		 * the Curses UI.
+		 */
+		gdk_window_freeze_updates(top_window);
+
+		teco_sigint_occurred = FALSE;
+		teco_interface_handle_key_press(event->key.keyval, event->key.state, &error);
+		teco_sigint_occurred = FALSE;
+
+		gdk_window_thaw_updates(top_window);
+
+		if (g_error_matches(error, TECO_ERROR, TECO_ERROR_QUIT)) {
+			gtk_main_quit();
+			break;
+		}
+
+		/*
+		 * This should give the UI a chance to update after every keypress.
+		 * Would also be possible but tricky to implement with an idle watcher.
+		 */
+		gtk_main_iteration_do(FALSE);
+	} while (!g_queue_is_empty(teco_interface.event_queue));
 
 	return TRUE;
 }