Introduce our own shutdown callback mechanism.

Instead of adding stuff to `_shutdown()`, we can now register a shutdown
routine from the respective `init()` function of our modules.

This also has the advantage, that we're sure they're called in reverse
order from how the initialization happened.

I didn't simply use `atexit()` because POSIX says that the number of
possible callbacks is limited (min 32) and I was not sure whether
we will maybe extend this number at one point.

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

src/ui/core.c

@@ -89,10 +89,26 @@ static Display* display;
 
 static void _ui_draw_term_title(void);
 
+static void
+_ui_close(void)
+{
+    g_timer_destroy(ui_idle_time);
+    endwin();
+    notifier_uninit();
+    cons_clear_alerts();
+    wins_destroy();
+    inp_close();
+    status_bar_close();
+    free_title_bar();
+    delwin(main_scr);
+    delscreen(set_term(NULL));
+}
+
 void
 ui_init(void)
 {
     log_info("Initialising UI");
+    prof_add_shutdown_routine(_ui_close);
     main_scr = initscr();
     nonl();
     cbreak();
@@ -180,21 +196,6 @@ ui_reset_idle_time(void)
     g_timer_start(ui_idle_time);
 }
 
-void
-ui_close(void)
-{
-    g_timer_destroy(ui_idle_time);
-    endwin();
-    notifier_uninit();
-    cons_clear_alerts();
-    wins_destroy();
-    inp_close();
-    status_bar_close();
-    free_title_bar();
-    delwin(main_scr);
-    delscreen(set_term(NULL));
-}
-
 void
 ui_resize(void)
 {

src/ui/tray.c

@@ -153,9 +153,21 @@ _tray_change_icon(gpointer data)
     return TRUE;
 }
 
+static void
+_tray_shutdown(void)
+{
+    if (gtk_ready && prefs_get_boolean(PREF_TRAY)) {
+        tray_disable();
+    }
+    g_string_free(icon_filename, TRUE);
+    g_string_free(icon_msg_filename, TRUE);
+    gtk_main_quit();
+}
+
 void
 tray_init(void)
 {
+    prof_add_shutdown_routine(_tray_shutdown);
     _get_icons();
     gtk_ready = gtk_init_check(0, NULL);
     log_debug("Env is GTK-ready: %s", gtk_ready ? "true" : "false");
@@ -179,17 +191,6 @@ tray_update(void)
     }
 }
 
-void
-tray_shutdown(void)
-{
-    if (gtk_ready && prefs_get_boolean(PREF_TRAY)) {
-        tray_disable();
-    }
-    g_string_free(icon_filename, TRUE);
-    g_string_free(icon_msg_filename, TRUE);
-    gtk_main_quit();
-}
-
 void
 tray_set_timer(int interval)
 {

src/ui/tray.h

@@ -39,7 +39,6 @@
 #ifdef HAVE_GTK
 void tray_init(void);
 void tray_update(void);
-void tray_shutdown(void);
 
 void tray_enable(void);
 void tray_disable(void);

src/ui/ui.h

@@ -62,7 +62,6 @@
 void ui_init(void);
 void ui_load_colours(void);
 void ui_update(void);
-void ui_close(void);
 void ui_redraw(void);
 void ui_resize(void);
 void ui_focus_win(ProfWin* window);