gdate: add g_date_copy()

This will allow passing invalid GDates through GValues.

https://bugzilla.gnome.org/show_bug.cgi?id=760109

docs/reference/glib/glib-sections.txt

@@ -1551,6 +1551,7 @@ g_date_new_dmy
 g_date_new_julian
 g_date_clear
 g_date_free
+g_date_copy
 
 <SUBSECTION>
 g_date_set_day

glib/gdate.c

@@ -342,6 +342,35 @@ g_date_free (GDate *date)
   g_free (date);
 }
 
+/**
+ * g_date_copy:
+ * @date: a #GDate to copy
+ *
+ * Copies a GDate to a newly-allocated GDate. If the input was invalid
+ * (as determined by g_date_valid()), the invalid state will be copied
+ * as is into the new object.
+ *
+ * Returns: (transfer full): a newly-allocated #GDate initialized from @date
+ *
+ * Since: 2.56
+ */
+GDate *
+g_date_copy (const GDate *date)
+{
+  GDate *res;
+  g_return_val_if_fail (date != NULL, NULL);
+
+  if (g_date_valid (date))
+    res = g_date_new_julian (g_date_get_julian (date));
+  else
+    {
+      res = g_date_new ();
+      *res = *date;
+    }
+
+  return res;
+}
+
 /**
  * g_date_valid:
  * @date: a #GDate to check

glib/gdate.h

@@ -127,6 +127,8 @@ GLIB_AVAILABLE_IN_ALL
 GDate*       g_date_new_julian            (guint32      julian_day);
 GLIB_AVAILABLE_IN_ALL
 void         g_date_free                  (GDate       *date);
+GLIB_AVAILABLE_IN_2_56
+GDate*       g_date_copy                  (const GDate *date);
 
 /* check g_date_valid() after doing an operation that might fail, like
  * _parse.  Almost all g_date operations are undefined on invalid

glib/tests/date.c

@@ -357,6 +357,32 @@ test_order (void)
   g_assert (g_date_compare (&d1, &d2) == 1);
 }
 
+static void
+test_copy (void)
+{
+  GDate *d;
+  GDate *c;
+
+  d = g_date_new ();
+  g_assert_false (g_date_valid (d));
+
+  c = g_date_copy (d);
+  g_assert_nonnull (c);
+  g_assert_false (g_date_valid (c));
+  g_date_free (c);
+
+  g_date_set_day (d, 10);
+
+  c = g_date_copy (d);
+  g_date_set_month (c, 1);
+  g_date_set_year (c, 2015);
+  g_assert_true (g_date_valid (c));
+  g_assert_cmpuint (g_date_get_day (c), ==, 10);
+  g_date_free (c);
+
+  g_date_free (d);
+}
+
 int
 main (int argc, char** argv)
 {
@@ -401,6 +427,7 @@ main (int argc, char** argv)
       g_test_add_data_func (path, GINT_TO_POINTER(check_years[i]), test_year);
       g_free (path);
     }
+  g_test_add_func ("/date/copy", test_copy);
 
   return g_test_run ();
 }

gobject/gboxed.c

@@ -109,12 +109,6 @@ _g_boxed_type_init (void)
   g_assert (type == G_TYPE_BOXED);
 }
 
-static GDate *
-gdate_copy (GDate *date)
-{
-  return g_date_new_julian (g_date_get_julian (date));
-}
-
 static GString *
 gstring_copy (GString *src_gstring)
 {
@@ -130,7 +124,7 @@ gstring_free (GString *gstring)
 G_DEFINE_BOXED_TYPE (GClosure, g_closure, g_closure_ref, g_closure_unref)
 G_DEFINE_BOXED_TYPE (GValue, g_value, value_copy, value_free)
 G_DEFINE_BOXED_TYPE (GValueArray, g_value_array, g_value_array_copy, g_value_array_free)
-G_DEFINE_BOXED_TYPE (GDate, g_date, gdate_copy, g_date_free)
+G_DEFINE_BOXED_TYPE (GDate, g_date, g_date_copy, g_date_free)
 /* the naming is a bit odd, but GString is obviously not G_TYPE_STRING */
 G_DEFINE_BOXED_TYPE (GString, g_gstring, gstring_copy, gstring_free)
 G_DEFINE_BOXED_TYPE (GHashTable, g_hash_table, g_hash_table_ref, g_hash_table_unref)