compile time check on signal callback signature

Author: dterrahe

src/gui/gtk.h

@@ -569,6 +569,100 @@ GtkEventController *(dt_gui_connect_motion)(GtkWidget *widget,
   ASSERT_FUNC_TYPE(leave, void(*)(GtkEventControllerMotion *, __typeof__(data))), \
   dt_gui_connect_motion(GTK_WIDGET(widget), G_CALLBACK(motion), G_CALLBACK(enter), G_CALLBACK(leave), (data)))
 
+// Enable compile-time checking of signal handler signatures
+// Uncomment the _Static_assert to stop compilation on mismatch
+// Otherwise errors will be printed at runtime, but only when the signal is connected
+// (so all dialogs, menus etc must be opened to see all errors)
+// No code is generated when the test is passed
+#if 1 && !defined(__cplusplus)
+#undef G_CALLBACK
+static inline GCallback G_CALLBACK(void *f) { return (GCallback)f; } // as a macro it gets expanded before reaching here
+#define DISABLINGPREFIXG_CALLBACK
+
+#define SIGNAME(num, signal, name) !strcmp((signal), #name) ? 1 << num :
+#define RETURN_HANDLER(num, ret, instance, data, ...) ret(*)(__typeof__(instance), __VA_OPT__(__VA_ARGS__,) __typeof__(data)) : 1 << num,
+#define BOOL_HANDLER(num, instance, data, ...) RETURN_HANDLER(num, gboolean, instance, data, __VA_ARGS__)
+#define VOID_HANDLER(num, instance, data, ...) RETURN_HANDLER(num, void, instance, data, __VA_ARGS__)
+#define EVENT_HANDLER(instance, data, event) BOOL_HANDLER(0, instance, data, GdkEvent##event*) \
+                                             BOOL_HANDLER(0, instance, data, const GdkEvent##event*)
+#undef _Static_assert
+#undef  g_signal_connect
+#define g_signal_connect(instance, signal, c_handler, data) do { \
+  const int required_signature = \
+    SIGNAME(0, signal, event) \
+    SIGNAME(0, signal, button-press-event) \
+    SIGNAME(0, signal, button-release-event) \
+    SIGNAME(0, signal, motion-notify-event) \
+    SIGNAME(0, signal, scroll-event) \
+    SIGNAME(0, signal, enter-notify-event) \
+    SIGNAME(0, signal, leave-notify-event) \
+    SIGNAME(0, signal, key-press-event) \
+    SIGNAME(0, signal, focus-out-event) \
+    SIGNAME(0, signal, focus-in-event) \
+    SIGNAME(0, signal, delete-event) \
+    SIGNAME(0 | 1 << 1 | 1 << 2 , signal, changed) \
+    SIGNAME(1 | 1 << 4, signal, toggled) \
+    SIGNAME(1, signal, clicked) \
+    SIGNAME(1, signal, value-changed) \
+    SIGNAME(1, signal, value-reset) \
+    SIGNAME(1, signal, quad-pressed) \
+    SIGNAME(1, signal, show) \
+    SIGNAME(1, signal, stopped) \
+    SIGNAME(1, signal, stop-search) \
+    SIGNAME(1, signal, day_selected) \
+    SIGNAME(1, signal, day_selected-double-click) \
+    SIGNAME(1, signal, selection-changed) \
+    SIGNAME(1, signal, activate) \
+    SIGNAME(1, signal, deactivate) \
+    SIGNAME(1, signal, style-updated) \
+    SIGNAME(1, signal, color-set) \
+    SIGNAME(3, signal, moved-to-rect) \
+    SIGNAME(5, signal, query-tooltip) \
+    SIGNAME(6, signal, draw) \
+    SIGNAME(8, signal, cancel) \
+    SIGNAME(8, signal, size-allocate) \
+    SIGNAME(8, signal, drag-begin) \
+    SIGNAME(8, signal, drag-end) \
+    SIGNAME(9, signal, drag-leave) \
+    SIGNAME(9, signal, switch-page) \
+    SIGNAME(10, signal, drag-motion) \
+    SIGNAME(10, signal, drag-drop) \
+    SIGNAME(30, signal, pressed) \
+    SIGNAME(30, signal, released) \
+    SIGNAME(30, signal, motion) \
+    SIGNAME(30, signal, enter) \
+    SIGNAME(30, signal, leave) \
+    1 << 31; \
+  const int found_signature = _Generic((DISABLINGPREFIX##c_handler), \
+    EVENT_HANDLER(instance, data, ) \
+    EVENT_HANDLER(instance, data, Button) \
+    EVENT_HANDLER(instance, data, Motion) \
+    EVENT_HANDLER(instance, data, Scroll) \
+    EVENT_HANDLER(instance, data, Key) \
+    EVENT_HANDLER(instance, data, Focus) \
+    EVENT_HANDLER(instance, data, Crossing) \
+    VOID_HANDLER(1, instance, data) \
+    VOID_HANDLER(2, instance, data, char*, GtkTreeIter*) \
+    VOID_HANDLER(3, instance, data, GdkRectangle*, GdkRectangle*, gboolean, gboolean) \
+    VOID_HANDLER(4, instance, data, char*) \
+    BOOL_HANDLER(5, instance, data, gint, gint, gboolean, GtkTooltip*) \
+    BOOL_HANDLER(6, instance, data, cairo_t*) \
+    VOID_HANDLER(8, instance, data, GdkRectangle*) \
+    VOID_HANDLER(8, instance, data, GdkEventSequence*) \
+    VOID_HANDLER(8, instance, data, GdkDragContext*) \
+    VOID_HANDLER(9, instance, data, GdkDragContext*, guint) \
+    VOID_HANDLER(9, instance, data, GtkWidget*, guint) \
+    BOOL_HANDLER(10, instance, data, GdkDragContext*, const gint, const gint, const guint) \
+    GCallback : 1 << 30, \
+    default : 1 << 31); \
+  if(required_signature == 1 << 31) \
+    dt_print_nts_ext("%s:%d: connecting unknown signal %s\n", __FILE__, __LINE__, signal); \
+  else if(!(required_signature & found_signature)) \
+    dt_print_nts_ext("%s:%d: connecting signal %s to %s with incorrect signature\n", __FILE__, __LINE__, signal, #c_handler); \
+  /*_Static_assert(required_signature & found_signature, "incorrect function connected to " signal );*/ \
+  g_signal_connect_data ((instance), (signal), (c_handler), (data), NULL, (GConnectFlags) 0); } while(0)
+#endif // __cplusplus
+
 // GTK4 gtk_event_controller_get_current_event_state(GTK_EVENT_CONTROLLER(controller));
 #define dt_modifier_eq(controller, mask)\
   dt_modifier_is(dt_key_modifier_state(), mask)