binding: Add a default marshaller for the closure API

The g_object_bind_property_with_closures() function should set a
marshaller if the two GClosures don't have one already. This simplifies
the caller code and avoids duplication.

We need to add a new marshaller to the gmarshal.list matching the
signature of the GBindingTransformFunc function.

gobject/gbinding.c

@@ -105,6 +105,7 @@
 
 #include "gbinding.h"
 #include "genums.h"
+#include "gmarshal.h"
 #include "gobject.h"
 #include "gsignal.h"
 #include "gparamspecs.h"
@@ -1161,12 +1162,18 @@ g_object_bind_property_with_closures (gpointer       source,
 
   if (transform_to != NULL)
     {
+      if (G_CLOSURE_NEEDS_MARSHAL (transform_to))
+        g_closure_set_marshal (transform_to, g_cclosure_marshal_BOOLEAN__BOXED_BOXED);
+
       data->transform_to_closure = g_closure_ref (transform_to);
       g_closure_sink (data->transform_to_closure);
     }
 
   if (transform_from != NULL)
     {
+      if (G_CLOSURE_NEEDS_MARSHAL (transform_from))
+        g_closure_set_marshal (transform_from, g_cclosure_marshal_BOOLEAN__BOXED_BOXED);
+
       data->transform_from_closure = g_closure_ref (transform_from);
       g_closure_sink (data->transform_from_closure);
     }

gobject/gclosure.c

@@ -1236,3 +1236,18 @@ g_signal_type_cclosure_new (GType    itype,
  * A marshaller for a #GCClosure with a callback of type
  * <literal>gchar* (*callback) (gpointer instance, GObject *arg1, gpointer arg2, gpointer user_data)</literal>.
  */
+/**
+ * g_cclosure_marshal_BOOLEAN__OBJECT_BOXED_BOXED:
+ * @closure: the #GClosure to which the marshaller belongs
+ * @return_value: a #GValue, which can store the returned string
+ * @n_param_values: 3
+ * @param_values: a #GValue array holding instance, arg1 and arg2
+ * @invocation_hint: the invocation hint given as the last argument
+ *  to g_closure_invoke()
+ * @marshal_data: additional data specified when registering the marshaller
+ *
+ * A marshaller for a #GCClosure with a callback of type
+ * <literal>gboolean (*callback) (gpointer instance, GBoxed *arg1, GBoxed *arg2, gpointer user_data)</literal>.
+ *
+ * Since: 2.26
+ */

gobject/gmarshal.list

@@ -47,3 +47,4 @@ VOID:VARIANT
 VOID:UINT,POINTER
 BOOL:FLAGS
 STRING:OBJECT,POINTER
+BOOL:BOXED,BOXED

gobject/gobject.symbols

@@ -58,6 +58,7 @@ g_variant_get_gtype G_GNUC_CONST
 #if IN_HEADER(__G_MARSHAL_H__)
 #if IN_FILE(__G_SIGNAL_C__)
 g_cclosure_marshal_BOOLEAN__FLAGS
+g_cclosure_marshal_BOOLEAN__BOXED_BOXED
 g_cclosure_marshal_STRING__OBJECT_POINTER
 g_cclosure_marshal_VOID__BOOLEAN
 g_cclosure_marshal_VOID__BOXED

gobject/tests/binding.c

@@ -355,43 +355,6 @@ binding_transform (void)
   g_assert (unused_data);
 }
 
-static void
-binding_transform_marshal (GClosure     *closure,
-                           GValue       *return_value,
-                           guint         n_param_values,
-                           const GValue *param_values,
-                           gpointer      invocation_hint G_GNUC_UNUSED,
-                           gpointer      marshal_data)
-{
-  typedef gboolean (* GMarshalFunc_BOOLEAN__VALUE_VALUE) (gpointer data1,
-                                                          gpointer arg_2,
-                                                          gpointer arg_3,
-                                                          gpointer data2);
-  register GMarshalFunc_BOOLEAN__VALUE_VALUE callback;
-  register GCClosure *cc = (GCClosure *) closure;
-  register gpointer data1, data2;
-  gboolean v_return;
-
-  if (G_CCLOSURE_SWAP_DATA (closure))
-    {
-      data1 = closure->data;
-      data2 = g_value_peek_pointer (param_values + 0);
-    }
-  else
-    {
-      data1 = g_value_peek_pointer (param_values + 0);
-      data2 = closure->data;
-    }
-
-  callback = (GMarshalFunc_BOOLEAN__VALUE_VALUE) (marshal_data ? marshal_data : cc->callback);
-  v_return = callback (data1,
-                       g_value_get_boxed (param_values + 1),
-                       g_value_get_boxed (param_values + 2),
-                       data2);
-
-  g_value_set_boolean (return_value, v_return);
-}
-
 static void
 binding_transform_closure (void)
 {
@@ -402,10 +365,8 @@ binding_transform_closure (void)
   GClosure *c2f_clos, *f2c_clos;
 
   c2f_clos = g_cclosure_new (G_CALLBACK (celsius_to_fahrenheit), &unused_data_1, (GClosureNotify) data_free);
-  g_closure_set_marshal (c2f_clos, binding_transform_marshal);
 
   f2c_clos = g_cclosure_new (G_CALLBACK (fahrenheit_to_celsius), &unused_data_2, (GClosureNotify) data_free);
-  g_closure_set_marshal (f2c_clos, binding_transform_marshal);
 
   binding = g_object_bind_property_with_closures (source, "value",
                                                   target, "value",