win: Implement stronger theme compatibility for frame_obj

The frame object requires a theme of version 119 or more. In fact
I think until we are totally happy with the window API (for EO) we
might want to bump that version regularly. That would indeed disallow
theme customization for border.edc until it's done.

This patch uses a pretty brute force way to set the theme file to
the default file from EFL installation. elm_config is not reliable
here.

This is very custom made and there may be a more generic way to force
a widget to use a minimum theme version. Yes that could mean ugly
widgets if we change the theme API but at least that would make them
work. Note that the border theme contains no visual elements, so the
colors of the background, etc... should all depend on the user
selected theme. But of course CSD (in Wayland) will have to use the
default theme -- and look grey.

Fixes D4976

data/elementary/themes/edc/elm/bg.edc

@@ -7,7 +7,7 @@
 */
 
 group { name: "elm/bg/base/default";
-   data.item: "elm_bg_version" "119";
+   data.item: "version" "119";
    images.image: "bevel_dark_out.png" COMP;
    parts {
       part { name: "base"; type: RECT;

data/elementary/themes/edc/elm/border.edc

@@ -30,6 +30,7 @@ group { name: "elm/border/base/default";
    images.image: "screen_circular_shadow.png" COMP;
    images.image: "win_shadow.png" COMP;
    data.item: "shadow" "1";
+   data.item: "version" "119";
    parts {
       /* opaque region of the window, to inform the compositor */
       spacer { "elm.spacer.opaque";

data/elementary/themes/edc/elm/win.edc

@@ -1,5 +1,5 @@
 group { name: "elm/win/base/default";
-   data.item: "elm_win_version" "119";
+   data.item: "version" "119";
    parts {
       rect { "client_clip"; nomouse;
          desc { "default";

src/lib/elementary/efl_ui_win.c

@@ -28,6 +28,8 @@
 #define MY_CLASS_NAME "Efl.Ui.Win"
 #define MY_CLASS_NAME_LEGACY "elm_win"
 
+#define FRAME_OBJ_THEME_MIN_VERSION 119
+
 static const Elm_Win_Trap *trap = NULL;
 
 #define TRAP(sd, name, ...)                                             \
@@ -2150,9 +2152,9 @@ static inline Edje_Object *
 _elm_win_modal_blocker_edje_get(Efl_Ui_Win_Data *sd)
 {
    /* Legacy theme compatibility */
-   const char *version = edje_object_data_get(sd->legacy.edje, "elm_win_version");
+   const char *version = edje_object_data_get(sd->legacy.edje, "version");
    int v = version ? atoi(version) : 0;
-   if (v < 119)
+   if (v < FRAME_OBJ_THEME_MIN_VERSION)
      {
         DBG("Detected legacy theme (<1.19) for modal window blocker.");
         return sd->legacy.edje;
@@ -4071,22 +4073,79 @@ _elm_object_part_cursor_set(Evas_Object *obj, Evas_Object *edj,
    elm_object_sub_cursor_set(sub, obj, cursor);
 }
 
+static char *
+_efl_system_theme_path_get(void)
+{
+   // Find the default theme from EFL install. Quite ugly.
+   const char *sysdir;
+   char *version;
+   char path[PATH_MAX];
+   int v;
+
+   sysdir = elm_theme_system_dir_get();
+   if (!sysdir) return NULL;
+
+   eina_file_path_join(path, PATH_MAX, sysdir, "default.edj");
+   version = edje_file_data_get(path, "version");
+   v = version ? atoi(version) : 0;
+   free(version);
+   if (v < FRAME_OBJ_THEME_MIN_VERSION)
+     {
+        ERR("Default system theme is too old, something is wrong with your installation of EFL.");
+        return NULL;
+     }
+
+   return strdup(path);
+}
+
 static void
 _elm_win_frame_add(Efl_Ui_Win_Data *sd, const char *style)
 {
    Evas_Object *obj = sd->obj;
-   int w, h, mw, mh;
-   /* short layer; */
+   int w, h, mw, mh, v;
+   const char *version;
 
    if (sd->frame_obj) return;
+
    sd->frame_obj = edje_object_add(sd->evas);
-   /* layer = evas_object_layer_get(obj); */
-   /* evas_object_layer_set(sd->frame_obj, layer + 1); */
-   if (!elm_widget_theme_object_set
-       (sd->obj, sd->frame_obj, "border", "base", style))
+
+   // Verify theme version. Border requires an exact theme API.
+   version = elm_theme_data_get(elm_widget_theme_get(sd->obj), "version");
+   v = version ? atoi(version) : 0;
+   if (EINA_LIKELY(v >= FRAME_OBJ_THEME_MIN_VERSION))
      {
-        ELM_SAFE_FREE(sd->frame_obj, evas_object_del);
-        return;
+        if (!elm_widget_theme_object_set
+            (sd->obj, sd->frame_obj, "border", "base", style))
+          {
+             ERR("Failed to set main border theme for the window.");
+             ELM_SAFE_FREE(sd->frame_obj, evas_object_del);
+             return;
+          }
+
+        // Verify border.edc version as well
+        version = edje_object_data_get(sd->frame_obj, "version");
+        v = version ? atoi(version) : 0;
+     }
+
+   if (v < FRAME_OBJ_THEME_MIN_VERSION)
+     {
+        // Theme compatibility
+        const char *key = "elm/border/base/default"; // FIXME?
+        char *sys_theme;
+
+        WRN("Selected theme does not support the required border theme API "
+            "(version = %d, requires >= %d).",
+            v, FRAME_OBJ_THEME_MIN_VERSION);
+        sys_theme = _efl_system_theme_path_get();
+        if (!sys_theme ||
+            !edje_object_file_set(sd->frame_obj, sys_theme, key))
+          {
+             ERR("Failed to set main border theme for the window.");
+             ELM_SAFE_FREE(sd->frame_obj, evas_object_del);
+             free(sys_theme);
+             return;
+          }
+        free(sys_theme);
      }
 
    /* Small hack: The special value 2 means this is the top frame object.
@@ -6318,9 +6377,10 @@ _elm_win_bg_must_swallow(Efl_Ui_Win_Data *sd)
         wd = efl_data_scope_get(bg, ELM_WIDGET_CLASS);
         if (wd)
           {
-             version = edje_object_data_get(wd->resize_obj, "elm_bg_version");
+             version = edje_object_data_get(wd->resize_obj, "version");
              v = version ? atoi(version) : 0;
-             if (v >= 119) sd->legacy.bg_must_swallow = 0;
+             if (v >= FRAME_OBJ_THEME_MIN_VERSION)
+               sd->legacy.bg_must_swallow = 0;
           }
         evas_object_del(bg);
      }

src/lib/elementary/elm_priv.h

@@ -403,7 +403,7 @@ Eina_Bool            _elm_theme_icon_set(Elm_Theme *th,
                                          Evas_Object *o,
                                          const char *group,
                                          const char *style);
-Eina_Bool            _elm_theme_parse(Elm_Theme *th,
+void                 _elm_theme_parse(Elm_Theme *th,
                                       const char *theme);
 void                 _elm_theme_shutdown(void);
 

src/lib/elementary/elm_theme.c

@@ -45,12 +45,14 @@ _elm_theme_item_finalize(Elm_Theme_Files *files,
    if (istheme)
      {
         char *version;
+        int v;
 
         if (!(version = edje_mmap_data_get(f, "version"))) return;
-        if (atoi(version) < 110) // bump this version number when we need to
+        v = atoi(version);
+        if (v < 110) // bump this version number when we need to
           {
+             WRN("Selected theme is too old (version = %d, needs >= 110)", v);
              free(version);
-             return;
           }
         free(version);
      }
@@ -321,7 +323,7 @@ _elm_theme_set(Elm_Theme *th, Evas_Object *o, const char *clas, const char *grou
         eina_hash_add(th->cache_style_load_failed, buf2, (void *)1);
      }
 
-   //Use the elementary default theme.
+   // Use the elementary default style.
    snprintf(buf2, sizeof(buf2), "elm/%s/%s/default", clas, group);
    if (!eina_hash_find(th->cache_style_load_failed, buf2))
      {
@@ -385,7 +387,7 @@ _elm_theme_icon_set(Elm_Theme *th,
    return w > 0;
 }
 
-Eina_Bool
+void
 _elm_theme_parse(Elm_Theme *th, const char *theme)
 {
    Eina_List *names = NULL;
@@ -459,7 +461,6 @@ _elm_theme_parse(Elm_Theme *th, const char *theme)
 
    EINA_LIST_FREE(names, p)
      _elm_theme_file_item_add(&th->themes, p, EINA_FALSE, EINA_TRUE);
-   return EINA_TRUE;
 }
 
 void