elm: Always pass valid part name inside part APIs

This affects the legacy content_set/get/unset part APIs. This
should avoid some unwanted ERR messages in case an elm_object_
API is used on an elm widget that doesn't implement said API.

What this does is request the widget for the name of the default
part if NULL was passed in. Since some widgets are not elm_layout,
they have to override the API themselves, which is why I made it
an internal EO API (rather than a series of efl_isa()).

In theory, part should never be NULL when reaching the internal
implementation code in the widgets, at least for content.

In EO, efl_part(obj, NULL) should be invalid.

Ref T5629

14 files changed, 103 insertions, 39 deletions

diff --git a/src/lib/elementary/efl_ui_flip.c b/src/lib/elementary/efl_ui_flip.c
index d6d1ac4d6f..074771251d 100644
--- a/src/lib/elementary/efl_ui_flip.c
+++ b/src/lib/elementary/efl_ui_flip.c
@@ -2400,6 +2400,7 @@ ELM_PART_IMPLEMENT(efl_ui_flip, EFL_UI_FLIP, Efl_Ui_Flip_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_SET(efl_ui_flip, EFL_UI_FLIP, Efl_Ui_Flip_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_GET(efl_ui_flip, EFL_UI_FLIP, Efl_Ui_Flip_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_UNSET(efl_ui_flip, EFL_UI_FLIP, Efl_Ui_Flip_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(efl_ui_flip, "front")
 #include "efl_ui_flip_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -2407,6 +2408,7 @@ ELM_PART_IMPLEMENT_CONTENT_UNSET(efl_ui_flip, EFL_UI_FLIP, Efl_Ui_Flip_Data, Elm
 /* Internal EO APIs and hidden overrides */
 
 #define EFL_UI_FLIP_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(efl_ui_flip), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(efl_ui_flip)
 
 #include "efl_ui_flip.eo.c"
diff --git a/src/lib/elementary/efl_ui_win.c b/src/lib/elementary/efl_ui_win.c
index 12bffbda5e..a87985ff11 100644
--- a/src/lib/elementary/efl_ui_win.c
+++ b/src/lib/elementary/efl_ui_win.c
@@ -6660,7 +6660,7 @@ if (x < 0) { x = 0; bad = 1; } } while (0)
 
 /* Efl.Part APIs */
 
-#define WIN_PART_ERR(part) ERR("No such part in window: '%s'. Supported parts are: 'background'.", part);
+#define WIN_PART_ERR(part) ERR("No such part in window: '%s'. Supported parts are: 'content' and 'background'.", part);
 
 static Eina_Bool
 _elm_win_bg_set(Efl_Ui_Win_Data *sd, Eo *bg)
@@ -6737,7 +6737,6 @@ static Eina_Bool
 _efl_ui_win_content_set(Eo *obj, Efl_Ui_Win_Data *sd, const char *part, Eo *content)
 {
    sd->legacy.forbidden = EINA_TRUE;
-   if (!part) part = "content";
    if (eina_streq(part, "content"))
      {
         if (sd->content == content) return EINA_TRUE;
@@ -6773,7 +6772,6 @@ static Efl_Canvas_Object *
 _efl_ui_win_content_get(Eo *obj EINA_UNUSED, Efl_Ui_Win_Data *sd, const char *part)
 {
    sd->legacy.forbidden = EINA_TRUE;
-   if (!part) part = "content";
    if (eina_streq(part, "content"))
      return sd->content;
    else if (eina_streq(part, "background"))
@@ -6909,25 +6907,26 @@ _efl_ui_win_internal_part_efl_file_file_get(Eo *obj, Elm_Part_Data *pd, const ch
 EOLIAN static Eina_Bool
 _efl_ui_win_efl_container_content_set(Eo *obj, Efl_Ui_Win_Data *sd, Evas_Object *content)
 {
-   return _efl_ui_win_content_set(obj, sd, NULL, content);
+   return _efl_ui_win_content_set(obj, sd, "content", content);
 }
 
 EOLIAN static Evas_Object*
 _efl_ui_win_efl_container_content_get(Eo *obj EINA_UNUSED, Efl_Ui_Win_Data *sd)
 {
-   return _efl_ui_win_content_get(obj, sd, NULL);
+   return _efl_ui_win_content_get(obj, sd, "content");
 }
 
 EOLIAN static Evas_Object*
 _efl_ui_win_efl_container_content_unset(Eo *obj, Efl_Ui_Win_Data *sd)
 {
-   return _efl_ui_win_content_unset(obj, sd, NULL);
+   return _efl_ui_win_content_unset(obj, sd, "content");
 }
 
 ELM_PART_IMPLEMENT(efl_ui_win, EFL_UI_WIN, Efl_Ui_Win_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_SET(efl_ui_win, EFL_UI_WIN, Efl_Ui_Win_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_GET(efl_ui_win, EFL_UI_WIN, Efl_Ui_Win_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_UNSET(efl_ui_win, EFL_UI_WIN, Efl_Ui_Win_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(efl_ui_win, "content")
 #include "efl_ui_win_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -8110,6 +8109,7 @@ elm_win_teamwork_uri_open(Efl_Ui_Win *obj EINA_UNUSED, const char *uri EINA_UNUS
 
 #define EFL_UI_WIN_EXTRA_OPS \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(efl_ui_win), \
+   ELM_PART_CONTENT_DEFAULT_OPS(efl_ui_win), \
    EFL_OBJECT_OP_FUNC(efl_canvas_object_legacy_ctor, _efl_ui_win_efl_canvas_object_legacy_ctor)
 
 #include "efl_ui_win.eo.c"
diff --git a/src/lib/elementary/elc_ctxpopup.c b/src/lib/elementary/elc_ctxpopup.c
index a32a0e867f..c60deb6dcb 100644
--- a/src/lib/elementary/elc_ctxpopup.c
+++ b/src/lib/elementary/elc_ctxpopup.c
@@ -1568,20 +1568,22 @@ _elm_ctxpopup_elm_interface_atspi_accessible_state_set_get(Eo *obj, Elm_Ctxpopup
    return ret;
 }
 
-/* Internal EO APIs and hidden overrides */
-
-#define ELM_CTXPOPUP_EXTRA_OPS \
-   EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_ctxpopup)
-
 /* Efl.Part begin */
 
 ELM_PART_OVERRIDE(elm_ctxpopup, ELM_CTXPOPUP, ELM_LAYOUT, Elm_Ctxpopup_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_SET(elm_ctxpopup, ELM_CTXPOPUP, ELM_LAYOUT, Elm_Ctxpopup_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_GET(elm_ctxpopup, ELM_CTXPOPUP, ELM_LAYOUT, Elm_Ctxpopup_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_UNSET(elm_ctxpopup, ELM_CTXPOPUP, ELM_LAYOUT, Elm_Ctxpopup_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_ctxpopup, "default")
 #include "elm_ctxpopup_internal_part.eo.c"
 
 /* Efl.Part end */
 
+/* Internal EO APIs and hidden overrides */
+
+#define ELM_CTXPOPUP_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_ctxpopup), \
+   EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_ctxpopup)
+
 #include "elm_ctxpopup_item.eo.c"
 #include "elm_ctxpopup.eo.c"
diff --git a/src/lib/elementary/elc_fileselector_entry.c b/src/lib/elementary/elc_fileselector_entry.c
index 25183fe05f..9d5684243a 100644
--- a/src/lib/elementary/elc_fileselector_entry.c
+++ b/src/lib/elementary/elc_fileselector_entry.c
@@ -681,6 +681,7 @@ ELM_PART_OVERRIDE_CONTENT_GET(elm_fileselector_entry, ELM_FILESELECTOR_ENTRY, EL
 ELM_PART_OVERRIDE_CONTENT_UNSET(elm_fileselector_entry, ELM_FILESELECTOR_ENTRY, ELM_LAYOUT, Elm_Fileselector_Entry_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_SET(elm_fileselector_entry, ELM_FILESELECTOR_ENTRY, ELM_LAYOUT, Elm_Fileselector_Entry_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_GET(elm_fileselector_entry, ELM_FILESELECTOR_ENTRY, ELM_LAYOUT, Elm_Fileselector_Entry_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_fileselector_entry, "button icon")
 #include "elm_fileselector_entry_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -688,6 +689,7 @@ ELM_PART_OVERRIDE_TEXT_GET(elm_fileselector_entry, ELM_FILESELECTOR_ENTRY, ELM_L
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_FILESELECTOR_ENTRY_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_fileselector_entry), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_fileselector_entry)
 
 #include "elm_fileselector_entry.eo.c"
diff --git a/src/lib/elementary/elc_player.c b/src/lib/elementary/elc_player.c
index c2204462ed..bd893996b9 100644
--- a/src/lib/elementary/elc_player.c
+++ b/src/lib/elementary/elc_player.c
@@ -709,6 +709,7 @@ _elm_player_elm_interface_atspi_widget_action_elm_actions_get(Eo *obj EINA_UNUSE
 
 ELM_PART_OVERRIDE(elm_player, ELM_PLAYER, ELM_LAYOUT, Elm_Player_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_SET(elm_player, ELM_PLAYER, ELM_LAYOUT, Elm_Player_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_player, "video")
 #include "elm_player_internal_part.eo.c"
 
 /* End of Efl.Part */
@@ -716,6 +717,7 @@ ELM_PART_OVERRIDE_CONTENT_SET(elm_player, ELM_PLAYER, ELM_LAYOUT, Elm_Player_Dat
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_PLAYER_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_player), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_player)
 
 #include "elm_player.eo.c"
diff --git a/src/lib/elementary/elc_popup.c b/src/lib/elementary/elc_popup.c
index e3ef8425af..f693de90bd 100644
--- a/src/lib/elementary/elc_popup.c
+++ b/src/lib/elementary/elc_popup.c
@@ -1929,6 +1929,7 @@ ELM_PART_OVERRIDE_CONTENT_GET(elm_popup, ELM_POPUP, ELM_LAYOUT, Elm_Popup_Data,
 ELM_PART_OVERRIDE_CONTENT_UNSET(elm_popup, ELM_POPUP, ELM_LAYOUT, Elm_Popup_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_SET(elm_popup, ELM_POPUP, ELM_LAYOUT, Elm_Popup_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_GET(elm_popup, ELM_POPUP, ELM_LAYOUT, Elm_Popup_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_popup, "default")
 #include "elm_popup_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -1936,6 +1937,7 @@ ELM_PART_OVERRIDE_TEXT_GET(elm_popup, ELM_POPUP, ELM_LAYOUT, Elm_Popup_Data, Elm
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_POPUP_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_popup), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_popup)
 
 #include "elm_popup.eo.c"
diff --git a/src/lib/elementary/elm_entry.c b/src/lib/elementary/elm_entry.c
index 2adc9f1230..1b7d37846d 100644
--- a/src/lib/elementary/elm_entry.c
+++ b/src/lib/elementary/elm_entry.c
@@ -6054,6 +6054,7 @@ ELM_PART_OVERRIDE_CONTENT_SET(elm_entry, ELM_ENTRY, ELM_LAYOUT, Elm_Entry_Data,
 ELM_PART_OVERRIDE_CONTENT_UNSET(elm_entry, ELM_ENTRY, ELM_LAYOUT, Elm_Entry_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_SET(elm_entry, ELM_ENTRY, ELM_LAYOUT, Elm_Entry_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_TEXT_GET(elm_entry, ELM_ENTRY, ELM_LAYOUT, Elm_Entry_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_entry, "icon")
 #include "elm_entry_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -6061,6 +6062,7 @@ ELM_PART_OVERRIDE_TEXT_GET(elm_entry, ELM_ENTRY, ELM_LAYOUT, Elm_Entry_Data, Elm
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_ENTRY_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_entry), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_entry)
 
 #include "elm_entry.eo.c"
diff --git a/src/lib/elementary/elm_layout.c b/src/lib/elementary/elm_layout.c
index 4364603359..84ec27f52a 100644
--- a/src/lib/elementary/elm_layout.c
+++ b/src/lib/elementary/elm_layout.c
@@ -2349,6 +2349,7 @@ _elm_layout_efl_part_part(const Eo *obj, Elm_Layout_Smart_Data *sd EINA_UNUSED,
    Elm_Part_Data *pd;
    Eo *proxy;
 
+   EINA_SAFETY_ON_NULL_RETURN_VAL(part, NULL);
    if (!_elm_layout_part_aliasing_eval(obj, &part, EINA_FALSE))
      return NULL;
 
@@ -2374,6 +2375,15 @@ _elm_layout_efl_part_part(const Eo *obj, Elm_Layout_Smart_Data *sd EINA_UNUSED,
    return proxy;
 }
 
+static const char *
+_elm_layout_default_content_part_get(const Eo *obj, Elm_Layout_Smart_Data *sd EINA_UNUSED)
+{
+   const char *part = NULL;
+   if (!_elm_layout_part_aliasing_eval(obj, &part, EINA_FALSE))
+     return NULL;
+   return part;
+}
+
 ELM_PART_IMPLEMENT_DESTRUCTOR(elm_layout, ELM_LAYOUT, Elm_Layout_Smart_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_SET(elm_layout, ELM_LAYOUT, Elm_Layout_Smart_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_GET(elm_layout, ELM_LAYOUT, Elm_Layout_Smart_Data, Elm_Part_Data)
@@ -2389,6 +2399,7 @@ ELM_PART_IMPLEMENT_TEXT_GET(elm_layout, ELM_LAYOUT, Elm_Layout_Smart_Data, Elm_P
 
 #define ELM_LAYOUT_EXTRA_OPS \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_layout), \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_layout), \
    EFL_OBJECT_OP_FUNC(efl_dbg_info_get, _elm_layout_efl_object_dbg_info_get)
 
 #include "elm_layout.eo.c"
diff --git a/src/lib/elementary/elm_mapbuf.c b/src/lib/elementary/elm_mapbuf.c
index 6181276868..fac6eeac07 100644
--- a/src/lib/elementary/elm_mapbuf.c
+++ b/src/lib/elementary/elm_mapbuf.c
@@ -445,6 +445,7 @@ ELM_PART_IMPLEMENT(elm_mapbuf, ELM_MAPBUF, Elm_Mapbuf_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_SET(elm_mapbuf, ELM_MAPBUF, Elm_Mapbuf_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_GET(elm_mapbuf, ELM_MAPBUF, Elm_Mapbuf_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_UNSET(elm_mapbuf, ELM_MAPBUF, Elm_Mapbuf_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_mapbuf, "default")
 #include "elm_mapbuf_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -452,6 +453,7 @@ ELM_PART_IMPLEMENT_CONTENT_UNSET(elm_mapbuf, ELM_MAPBUF, Elm_Mapbuf_Data, Elm_Pa
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_MAPBUF_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_mapbuf), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_mapbuf)
 
 #include "elm_mapbuf.eo.c"
diff --git a/src/lib/elementary/elm_notify.c b/src/lib/elementary/elm_notify.c
index 860a136690..faf2765e86 100644
--- a/src/lib/elementary/elm_notify.c
+++ b/src/lib/elementary/elm_notify.c
@@ -743,6 +743,7 @@ ELM_PART_IMPLEMENT(elm_notify, ELM_NOTIFY, Elm_Notify_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_SET(elm_notify, ELM_NOTIFY, Elm_Notify_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_GET(elm_notify, ELM_NOTIFY, Elm_Notify_Data, Elm_Part_Data)
 ELM_PART_IMPLEMENT_CONTENT_UNSET(elm_notify, ELM_NOTIFY, Elm_Notify_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_notify, "default")
 #include "elm_notify_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -750,6 +751,7 @@ ELM_PART_IMPLEMENT_CONTENT_UNSET(elm_notify, ELM_NOTIFY, Elm_Notify_Data, Elm_Pa
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_NOTIFY_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_notify), \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_notify)
 
 #include "elm_notify.eo.c"
diff --git a/src/lib/elementary/elm_part_helper.h b/src/lib/elementary/elm_part_helper.h
index 71d34c91e7..930ff6d19a 100644
--- a/src/lib/elementary/elm_part_helper.h
+++ b/src/lib/elementary/elm_part_helper.h
@@ -91,6 +91,11 @@ _ ## type ## _internal_part_efl_text_text_get(Eo *obj, partdata *pd) \
    ELM_PART_RETURN_VAL(_ ## type ## _text_get(pd->obj, pd->sd, pd->part)); \
 }
 
+#define ELM_PART_CONTENT_DEFAULT_SET(type, part) \
+   static const char * _ ## type ## _default_content_part_get(const Eo *obj EINA_UNUSED, void *sd EINA_UNUSED) { return part; }
+
+#define ELM_PART_CONTENT_DEFAULT_OPS(type) \
+   EFL_OBJECT_OP_FUNC(elm_widget_default_content_part_get, _ ## type ## _default_content_part_get)
 
 // For widgets that inherit from something with parts (eg. from Elm.Layout)
 #define ELM_PART_OVERRIDE(type, TYPE, SUPER, typedata, partdata) \
diff --git a/src/lib/elementary/elm_scroller.c b/src/lib/elementary/elm_scroller.c
index 22a7b855b9..faa063d343 100644
--- a/src/lib/elementary/elm_scroller.c
+++ b/src/lib/elementary/elm_scroller.c
@@ -1464,6 +1464,7 @@ ELM_PART_OVERRIDE(elm_scroller, ELM_SCROLLER, ELM_LAYOUT, Elm_Scroller_Data, Elm
 ELM_PART_OVERRIDE_CONTENT_SET(elm_scroller, ELM_SCROLLER, ELM_LAYOUT, Elm_Scroller_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_GET(elm_scroller, ELM_SCROLLER, ELM_LAYOUT, Elm_Scroller_Data, Elm_Part_Data)
 ELM_PART_OVERRIDE_CONTENT_UNSET(elm_scroller, ELM_SCROLLER, ELM_LAYOUT, Elm_Scroller_Data, Elm_Part_Data)
+ELM_PART_CONTENT_DEFAULT_SET(elm_scroller, "default")
 #include "elm_scroller_internal_part.eo.c"
 
 /* Efl.Part end */
@@ -1471,6 +1472,7 @@ ELM_PART_OVERRIDE_CONTENT_UNSET(elm_scroller, ELM_SCROLLER, ELM_LAYOUT, Elm_Scro
 /* Internal EO APIs and hidden overrides */
 
 #define ELM_SCROLLER_EXTRA_OPS \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_scroller), \
    EFL_CANVAS_GROUP_ADD_OPS(elm_scroller)
 
 #include "elm_scroller.eo.c"
diff --git a/src/lib/elementary/elm_widget.c b/src/lib/elementary/elm_widget.c
index 915a75e7a4..8bd35b138e 100644
--- a/src/lib/elementary/elm_widget.c
+++ b/src/lib/elementary/elm_widget.c
@@ -14,6 +14,7 @@
 #include "elm_priv.h"
 #include "elm_widget_container.h"
 #include "elm_interface_scrollable.h"
+#include "elm_part_helper.h"
 
 /* FIXME: remove this when we don't rely on evas event structs anymore */
 #define EFL_INTERNAL_UNSTABLE
@@ -3948,34 +3949,6 @@ _elm_widget_focus_reconfigure(Eo *obj, Elm_Widget_Smart_Data *_pd EINA_UNUSED)
    _elm_widget_focus_move_policy_reload(obj);
 }
 
-EAPI void
-elm_widget_content_part_set(Evas_Object *obj,
-                            const char *part,
-                            Evas_Object *content)
-{
-   ELM_WIDGET_CHECK(obj);
-   if (!efl_isa(obj, EFL_PART_INTERFACE)) return;
-   efl_content_set(efl_part(obj, part), content);
-}
-
-EAPI Evas_Object *
-elm_widget_content_part_get(const Evas_Object *obj,
-                            const char *part)
-{
-   ELM_WIDGET_CHECK(obj) NULL;
-   if (!efl_isa(obj, EFL_PART_INTERFACE)) return NULL;
-   return efl_content_get(efl_part(obj, part));
-}
-
-EAPI Evas_Object *
-elm_widget_content_part_unset(Evas_Object *obj,
-                              const char *part)
-{
-   ELM_WIDGET_CHECK(obj) NULL;
-   if (!efl_isa(obj, EFL_PART_INTERFACE)) return NULL;
-   return efl_content_unset(efl_part(obj, part));
-}
-
 EOLIAN static void
 _elm_widget_access_info_set(Eo *obj EINA_UNUSED, Elm_Widget_Smart_Data *sd, const char *txt)
 {
@@ -6521,10 +6494,64 @@ _elm_widget_focus_manager_factory(Eo *obj EINA_UNUSED, Elm_Widget_Smart_Data *pd
 }
 
 
+/* Legacy APIs */
+
+/* elm_object_content_xxx APIs are supposed to work on all objects for which
+ * elm_object_widget_check() returns true. The below checks avoid printing out
+ * undesired ERR messages. */
+EAPI void
+elm_widget_content_part_set(Evas_Object *obj,
+                            const char *part,
+                            Evas_Object *content)
+{
+   ELM_WIDGET_CHECK(obj);
+   if (!efl_isa(obj, EFL_PART_INTERFACE)) return;
+   if (!part)
+     {
+        part = elm_widget_default_content_part_get(obj);
+        if (!part) return;
+     }
+   efl_content_set(efl_part(obj, part), content);
+}
+
+EAPI Evas_Object *
+elm_widget_content_part_get(const Evas_Object *obj,
+                            const char *part)
+{
+   ELM_WIDGET_CHECK(obj) NULL;
+   if (!efl_isa(obj, EFL_PART_INTERFACE)) return NULL;
+   if (!part)
+     {
+        part = elm_widget_default_content_part_get(obj);
+        if (!part) return NULL;
+     }
+   return efl_content_get(efl_part(obj, part));
+}
+
+EAPI Evas_Object *
+elm_widget_content_part_unset(Evas_Object *obj,
+                              const char *part)
+{
+   ELM_WIDGET_CHECK(obj) NULL;
+   if (!efl_isa(obj, EFL_PART_INTERFACE)) return NULL;
+   if (!part)
+     {
+        part = elm_widget_default_content_part_get(obj);
+        if (!part) return NULL;
+     }
+   return efl_content_unset(efl_part(obj, part));
+}
+
+
 /* Internal EO APIs and hidden overrides */
 
+EFL_FUNC_BODY_CONST(elm_widget_default_content_part_get, const char *, NULL)
+
+ELM_PART_CONTENT_DEFAULT_SET(elm_widget, NULL)
+
 #define ELM_WIDGET_EXTRA_OPS \
    EFL_CANVAS_GROUP_ADD_DEL_OPS(elm_widget), \
+   ELM_PART_CONTENT_DEFAULT_OPS(elm_widget), \
    EFL_OBJECT_OP_FUNC(efl_dbg_info_get, _elm_widget_efl_object_dbg_info_get)
 
 #include "elm_widget_item.eo.c"
diff --git a/src/lib/elementary/elm_widget.h b/src/lib/elementary/elm_widget.h
index 2d7f49b132..01b2cccdc6 100644
--- a/src/lib/elementary/elm_widget.h
+++ b/src/lib/elementary/elm_widget.h
@@ -866,6 +866,9 @@ EAPI Eina_Bool _elm_layout_part_aliasing_eval(const Evas_Object *obj,
                                               const char **part,
                                               Eina_Bool is_text);
 
+/* Internal EO APIs */
+const char *elm_widget_default_content_part_get(const Eo *obj);
+
 
 #define ELM_WIDGET_ITEM_PROTECTED
 #include "elm_widget_item.eo.h"