edje: fix edje_part_helpers refcounting

Summary:
the reference from efl_reuse was forgotten & the parent relation was not
correctlty setted, which led to the fact that NOREF was never emitted.
This caused that thte object never really was destructed probebly, and
thus the del_interceptor_cb was not executed, and the object simply
leaked.

The test checks that those properties are correctly set, additionally a
error is printed in the efl code when a part has not the expected
reference properties. This also enforces errors when users are doing
wrong things with objects returned by efl_part.

Reviewers: ManMower, zmike

Reviewed By: zmike

Subscribers: cedric, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D6254

src/lib/edje/edje_part_helper.h

@@ -91,6 +91,8 @@ _edje_ ## type ## _internal_proxy_get(Edje_Object *obj EINA_UNUSED, Edje *ed, Ed
    else \
      { \
         PROXY_STATIC_VAR(type) = NULL; \
+        efl_parent_set(proxy, ed->obj); \
+        efl_unref(proxy); /* efl_reuse gives us one additional reference, give this one up as we gave ownerwhip back to ed->obj */\
         _edje_real_part_set(proxy, ed, rp, part); \
      } \
    __VA_ARGS__; \

src/lib/efl/interfaces/efl_interfaces_main.c

@@ -96,6 +96,12 @@ efl_part(const Eo *obj, const char *name)
    if (!r) return NULL;
 
    efl_event_callback_add(r, EFL_EVENT_NOREF, _noref_death, NULL);
+
+   //ensure that the parts that we have here are never leaked
+   //by checking theire references and ownership details
+   EINA_SAFETY_ON_NULL_RETURN_VAL(efl_parent_get(r), r);
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(efl_ref_count(r) == 1, r);
+
    ___efl_auto_unref_set(r, EINA_TRUE);
 
    return efl_ref(r);

src/tests/edje/edje_test_edje.c

@@ -1043,6 +1043,35 @@ EFL_START_TEST(edje_test_text_cursor)
 }
 EFL_END_TEST
 
+EFL_START_TEST(edje_test_part_caching)
+{
+   Evas *evas = EDJE_TEST_INIT_EVAS();
+   Evas_Object *ly, *o1, *global_p = NULL;
+
+   ly = efl_add(EFL_CANVAS_LAYOUT_CLASS, evas,
+    efl_file_set(efl_added, test_layout_get("test_swallows.edj"), "test_group")
+   );
+
+   for (int i = 0; i < 10; ++i)
+     {
+        Evas_Object *p;
+
+        p = efl_part(ly, "swallow");
+        o1 = efl_content_get(p);
+
+        if (global_p)
+          ck_assert_ptr_eq(global_p, p);
+        global_p = p;
+
+        ck_assert_int_eq(efl_ref_count(p), 1);
+        ck_assert_ptr_eq(efl_parent_get(p), NULL);
+
+     }
+
+   EDJE_TEST_FREE_EVAS();
+}
+EFL_END_TEST
+
 void edje_test_edje(TCase *tc)
 {
    tcase_add_test(tc, edje_test_edje_init);
@@ -1070,4 +1099,5 @@ void edje_test_edje(TCase *tc)
    tcase_add_test(tc, edje_test_signals);
    tcase_add_test(tc, edje_test_signal_callback_del_full);
    tcase_add_test(tc, edje_test_text_cursor);
+   tcase_add_test(tc, edje_test_part_caching);
 }