eo: Add API efl_data_scope_safe_get

This is a safe version of efl_data_scope_get, meaning that it will
return NULL if the object is not of the required type, or if there
is no data for that class, or if the given class was used as an
interface (and isn't a mixin).

@feature

src/lib/eo/Eo.h

@@ -1225,17 +1225,46 @@ EAPI Eo * _efl_add_internal_start(const char *file, int line, const Efl_Class *k
 
 /**
  * @brief Get a pointer to the data of an object for a specific class.
+ *
  * The data reference count is not incremented. The pointer must be used only
  * in the scope of the function and its callees.
+ *
  * @param obj the object to work on.
  * @param klass the klass associated with the data.
  * @return a pointer to the data.
  *
  * @see efl_data_ref()
  * @see efl_data_unref()
+ * @see efl_data_scope_safe_get()
  */
 EAPI void *efl_data_scope_get(const Eo *obj, const Efl_Class *klass);
 
+/**
+ * @brief Safely get a pointer to the data of an object for a specific class.
+ *
+ * This call runs a dynamic check and returns NULL if there is no valid data
+ * to return.
+ *
+ * The data reference count is not incremented. The pointer must be used only
+ * in the scope of the function and its callees. This function will return NULL
+ * if there is no data for this class, or if this object is not an instance of
+ * the given class. The function will return NULL if the data size is 0.
+ * Note that objects of class A inheriting from another class C as an
+ * interface (like: class A(B, C) {} ) will have no data for class C. This
+ * means that efl_isa(a, C) will return true but there is no data for C. This
+ * function's behaviour is similar to efl_data_scope_get() when running in
+ * debug mode (but this prints less error logs).
+ *
+ * @param obj the object to work on.
+ * @param klass the klass associated with the data.
+ * @return a pointer to the data or NULL in case of error or $obj was NULL.
+ *
+ * @see efl_data_scope_get()
+ *
+ * @since 1.20
+ */
+EAPI void *efl_data_scope_safe_get(const Eo *obj, const Efl_Class *klass);
+
 /**
  * @def efl_data_xref(obj, klass, ref_obj)
  * Use this macro if you want to associate a referencer object.

src/lib/eo/eo.c

@@ -1102,7 +1102,6 @@ _vtable_init(Eo_Vtable *vtable, size_t size)
    vtable->chain = calloc(vtable->size, sizeof(*vtable->chain));
 }
 
-#ifdef EO_DEBUG
 static Eina_Bool
 _eo_class_mro_has(const _Efl_Class *klass, const _Efl_Class *find)
 {
@@ -1116,7 +1115,6 @@ _eo_class_mro_has(const _Efl_Class *klass, const _Efl_Class *find)
      }
    return EINA_FALSE;
 }
-#endif
 
 static Eina_List *
 _eo_class_list_remove_duplicates(Eina_List* list)
@@ -2002,6 +2000,27 @@ err_klass:
    return ret;
 }
 
+EAPI void *
+efl_data_scope_safe_get(const Eo *obj_id, const Efl_Class *klass_id)
+{
+#ifndef EO_DEBUG
+   void *ret = NULL;
+
+   if (!obj_id) return NULL;
+   EO_OBJ_POINTER_RETURN_VAL(obj_id, obj, NULL);
+   EO_CLASS_POINTER_GOTO(klass_id, klass, err_klass);
+
+   if (_eo_class_mro_has(obj->klass, klass))
+     ret = _efl_data_scope_safe_get(obj, klass);
+
+err_klass:
+   EO_OBJ_DONE(obj_id);
+   return ret;
+#else
+   return efl_data_scope_get(obj_id, klass_id);
+#endif
+}
+
 EAPI void *
 efl_data_xref_internal(const char *file, int line, const Eo *obj_id, const Efl_Class *klass_id, const Eo *ref_obj_id)
 {

src/tests/eo/suite/eo_test_class_simple.c

@@ -142,7 +142,7 @@ static const Efl_Class_Description class_desc2 = {
      EO_VERSION,
      "Simple2",
      EFL_CLASS_TYPE_REGULAR,
-     0,
+     sizeof(Simple_Public_Data),
      _class_initializer2,
      NULL,
      NULL
@@ -150,6 +150,26 @@ static const Efl_Class_Description class_desc2 = {
 
 EFL_DEFINE_CLASS(simple2_class_get, &class_desc2, EO_CLASS, NULL)
 
+
+static Eina_Bool
+_class_initializer3(Efl_Class *klass)
+{
+   return efl_class_functions_set(klass, NULL, NULL);
+}
+
+static const Efl_Class_Description class_desc3 = {
+     EO_VERSION,
+     "Simple3",
+     EFL_CLASS_TYPE_REGULAR,
+     sizeof(Simple_Public_Data),
+     _class_initializer3,
+     NULL,
+     NULL
+};
+
+EFL_DEFINE_CLASS(simple3_class_get, &class_desc3, SIMPLE_CLASS, SIMPLE2_CLASS, NULL)
+
+
 static Efl_Object*
 _interface_get(Eo *obj EINA_UNUSED, void *pd EINA_UNUSED, const Efl_Object *klass)
 {

src/tests/eo/suite/eo_test_class_simple.h

@@ -29,6 +29,10 @@ EAPI int simple2_class_beef_get(const Efl_Class *obj);
 #define SIMPLE2_CLASS simple2_class_get()
 const Efl_Class *simple2_class_get(void);
 
+// simple3(simple, simple2)
+#define SIMPLE3_CLASS simple3_class_get()
+const Efl_Class *simple3_class_get(void);
+
 #define SEARCHABLE_CLASS searchable_class_get()
 const Efl_Class *searchable_class_get(void);
 

src/tests/eo/suite/eo_test_general.c

@@ -304,6 +304,29 @@ START_TEST(efl_data_fetch)
 }
 END_TEST
 
+START_TEST(efl_data_safe_fetch)
+{
+   efl_object_init();
+
+   Eo *obj = efl_add(SIMPLE2_CLASS, NULL);
+   fail_if(!obj || !efl_data_scope_safe_get(obj, SIMPLE2_CLASS));
+   efl_unref(obj);
+
+   obj = efl_add(SIMPLE3_CLASS, NULL);
+   fail_if(!obj);
+   fail_if(!efl_isa(obj, SIMPLE_CLASS));
+   fail_if(!efl_isa(obj, SIMPLE2_CLASS));
+   fail_if(!efl_isa(obj, SIMPLE3_CLASS));
+   fail_if(!efl_data_scope_safe_get(obj, SIMPLE_CLASS));
+   fail_if(!efl_data_scope_safe_get(obj, SIMPLE3_CLASS));
+   fail_if(efl_data_scope_safe_get(obj, SIMPLE2_CLASS) != NULL);
+   fail_if(efl_data_scope_safe_get(NULL, EFL_OBJECT_CLASS) != NULL);
+   efl_unref(obj);
+
+   efl_object_shutdown();
+}
+END_TEST
+
 START_TEST(efl_isa_tests)
 {
    efl_object_init();
@@ -1687,6 +1710,7 @@ void eo_test_general(TCase *tc)
    tcase_add_test(tc, efl_object_override_tests);
    tcase_add_test(tc, eo_signals);
    tcase_add_test(tc, efl_data_fetch);
+   tcase_add_test(tc, efl_data_safe_fetch);
    tcase_add_test(tc, efl_isa_tests);
    tcase_add_test(tc, efl_composite_tests);
    tcase_add_test(tc, eo_man_free);