minor fix for obj class (#2154)

* fix(class): correct the typo error in comment

* fix(class): return directly if the memory allocation fail

* fix(class): remove the unused code

* fix(class): remove parent argument from lv_obj_construct

since this argumnet is really used

* fix(class): replace stddef.h with stdint.h

since uint32_t is defined in stdint.h

src/core/lv_obj_class.c

@@ -24,7 +24,7 @@
 /**********************
  *  STATIC PROTOTYPES
  **********************/
-static void lv_obj_construct(lv_obj_t * obj, lv_obj_t * parent, const lv_obj_t * copy);
+static void lv_obj_construct(lv_obj_t * obj, const lv_obj_t * copy);
 static uint32_t get_instance_size(const lv_obj_class_t * class_p);
 
 /**********************
@@ -44,14 +44,12 @@ lv_obj_t * lv_obj_create_from_class(const lv_obj_class_t * class_p, lv_obj_t * p
     LV_TRACE_OBJ_CREATE("Creating object with %p class on %p parent", class_p, parent);
     uint32_t s = get_instance_size(class_p);
     lv_obj_t * obj = lv_mem_alloc(s);
+    if(obj == NULL) return NULL;
     lv_memset_00(obj, s);
     obj->class_p = class_p;
     obj->parent = parent;
-    const lv_obj_class_t * class_start = class_p;
 
-    while(class_start && class_start->constructor_cb == NULL) class_start = class_start->base_class;
+    lv_obj_construct(obj, copy);
-
-    lv_obj_construct(obj, parent, copy);
 
    if(parent) {
        /*Send a Call the ancestor's event handler to the parent to notify it about the new child.
@@ -63,7 +61,6 @@ lv_obj_t * lv_obj_create_from_class(const lv_obj_class_t * class_p, lv_obj_t * p
    }
 
     if(!copy) lv_theme_apply(obj);
-//    else lv_style_list_copy(&checkbox->style_indic, &checkbox_copy->style_indic);
 
     LV_TRACE_OBJ_CREATE("Object created at %p address with %p class on %p parent", obj, class_p, parent);
     return obj;
@@ -74,7 +71,7 @@ void _lv_obj_destruct(lv_obj_t * obj)
     if(obj->class_p->destructor_cb) obj->class_p->destructor_cb(obj);
 
     if(obj->class_p->base_class) {
-        /*Don't let the descendant methods run during constructing the ancestor type*/
+        /*Don't let the descendant methods run during destructing the ancestor type*/
         obj->class_p = obj->class_p->base_class;
 
         /*Call the base class's destructor too*/
@@ -98,7 +95,7 @@ bool lv_obj_is_editable(struct _lv_obj_t * obj)
  *   STATIC FUNCTIONS
  **********************/
 
-static void lv_obj_construct(lv_obj_t * obj, lv_obj_t * parent, const lv_obj_t * copy)
+static void lv_obj_construct(lv_obj_t * obj, const lv_obj_t * copy)
 {
     const lv_obj_class_t * original_class_p = obj->class_p;
 
@@ -107,16 +104,15 @@ static void lv_obj_construct(lv_obj_t * obj, lv_obj_t * parent, const lv_obj_t *
         obj->class_p = obj->class_p->base_class;
 
         /*Construct the base first*/
-        lv_obj_construct(obj, parent, copy);
+        lv_obj_construct(obj, copy);
     }
 
     /*Restore the original class*/
     obj->class_p = original_class_p;
 
     if(obj->class_p->constructor_cb) obj->class_p->constructor_cb(obj, copy);
-
-
 }
+
 static uint32_t get_instance_size(const lv_obj_class_t * class_p)
 {
     /*Find a base in which instance size is set*/

src/core/lv_obj_class.h

@@ -1,5 +1,5 @@
 /**
- * @file struct _lv_obj_tree.h
+ * @file lv_obj_class.h
  *
  */
 
@@ -13,7 +13,7 @@ extern "C" {
 /*********************
  *      INCLUDES
  *********************/
-#include <stddef.h>
+#include <stdint.h>
 #include <stdbool.h>
 
 /*********************
@@ -28,7 +28,7 @@ extern "C" {
 struct _lv_obj_t;
 
 typedef enum {
-    LV_OBJ_CLASS_EDITABLE_INHERIT,      /**< Check the base class. Must have 0 value to let he zero initialized class inherit*/
+    LV_OBJ_CLASS_EDITABLE_INHERIT,      /**< Check the base class. Must have 0 value to let zero initialized class inherit*/
     LV_OBJ_CLASS_EDITABLE_TRUE,
     LV_OBJ_CLASS_EDITABLE_FALSE,
 }lv_obj_class_editable_t;
@@ -37,13 +37,13 @@ typedef enum {
  * Describe the common methods of every object.
  * Similar to a C++ class.
  */
-typedef struct _lv_obj_class_t{
+typedef struct _lv_obj_class_t {
     const struct _lv_obj_class_t * base_class;
     void (*constructor_cb)(struct _lv_obj_t * obj, const struct _lv_obj_t * copy);
     void (*destructor_cb)(struct _lv_obj_t * obj);
     lv_event_cb_t event_cb;         /**< Object type specific event function*/
-    uint32_t editable :2;           /**< Value from ::lv_obj_class_editable_t*/
+    uint32_t editable : 2;          /**< Value from ::lv_obj_class_editable_t*/
-    uint32_t instance_size :20;
+    uint32_t instance_size : 20;
 }lv_obj_class_t;
 
 /**********************
@@ -52,7 +52,7 @@ typedef struct _lv_obj_class_t{
 
 /**
  * Create an object form a class descriptor
- * @param class_p pointer to  a class
+ * @param class_p pointer to a class
  * @param parent pointer to an object where the new object should be created
  * @param copy pointer to an other object with the same type to copy (DEPRECATED will be removed in v9)
  * @return pointer to the created object