Revert "[glib/ucdn/icu/ft/ot] Make returned funcs inert"

This reverts commit 5daf3bd4.

If other atexit callbacks try to destruct the objects we destruct
in atexit callbacks, bad things will happen.

I'll come up with some other way to catch premature destruction
of HB-owned objects.

Fixes https://github.com/behdad/harfbuzz/issues/618

src/hb-ft.cc

@@ -423,7 +423,6 @@ static hb_font_funcs_t *static_ft_funcs = nullptr;
 static
 void free_static_ft_funcs (void)
 {
-  hb_object_undo_inert (static_ft_funcs);
   hb_font_funcs_destroy (static_ft_funcs);
 }
 #endif
@@ -454,10 +453,8 @@ retry:
     hb_font_funcs_set_glyph_from_name_func (funcs, hb_ft_get_glyph_from_name, nullptr, nullptr);
 
     hb_font_funcs_make_immutable (funcs);
-    hb_object_make_inert (funcs);
 
     if (!hb_atomic_ptr_cmpexch (&static_ft_funcs, nullptr, funcs)) {
-      hb_object_undo_inert (funcs);
       hb_font_funcs_destroy (funcs);
       goto retry;
     }

src/hb-glib.cc

@@ -370,7 +370,6 @@ static hb_unicode_funcs_t *static_glib_funcs = nullptr;
 static
 void free_static_glib_funcs (void)
 {
-  hb_object_undo_inert (static_glib_funcs);
   hb_unicode_funcs_destroy (static_glib_funcs);
 }
 #endif
@@ -391,10 +390,8 @@ retry:
 #undef HB_UNICODE_FUNC_IMPLEMENT
 
     hb_unicode_funcs_make_immutable (funcs);
-    hb_object_make_inert (funcs);
 
     if (!hb_atomic_ptr_cmpexch (&static_glib_funcs, nullptr, funcs)) {
-      hb_object_undo_inert (funcs);
       hb_unicode_funcs_destroy (funcs);
       goto retry;
     }

src/hb-icu.cc

@@ -351,7 +351,6 @@ static hb_unicode_funcs_t *static_icu_funcs = nullptr;
 static
 void free_static_icu_funcs (void)
 {
-  hb_object_undo_inert (static_icu_funcs);
   hb_unicode_funcs_destroy (static_icu_funcs);
 }
 #endif
@@ -380,10 +379,8 @@ retry:
 #undef HB_UNICODE_FUNC_IMPLEMENT
 
     hb_unicode_funcs_make_immutable (funcs);
-    hb_object_make_inert (funcs);
 
     if (!hb_atomic_ptr_cmpexch (&static_icu_funcs, nullptr, funcs)) {
-      hb_object_undo_inert (funcs);
       hb_unicode_funcs_destroy (funcs);
       goto retry;
     }

src/hb-object-private.hh

@@ -41,10 +41,9 @@
 
 /* reference_count */
 
-#define HB_REFERENCE_COUNT_UNCHANGABLE_VALUE	-0x53043
-#define HB_REFERENCE_COUNT_UNREFFABLE_VALUE	-0x07734
-#define HB_REFERENCE_COUNT_UNTOUCHABLE_VALUE	-0xBEDAD
-#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT (HB_REFERENCE_COUNT_UNCHANGABLE_VALUE)}
+#define HB_REFERENCE_COUNT_INERT_VALUE -1
+#define HB_REFERENCE_COUNT_POISON_VALUE -0x0000DEAD
+#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT(HB_REFERENCE_COUNT_INERT_VALUE)}
 
 struct hb_reference_count_t
 {
@@ -54,23 +53,9 @@ struct hb_reference_count_t
   inline int get_unsafe (void) const { return ref_count.get_unsafe (); }
   inline int inc (void) { return ref_count.inc (); }
   inline int dec (void) { return ref_count.dec (); }
-  inline void finish (void) { ref_count.set_unsafe (HB_REFERENCE_COUNT_UNTOUCHABLE_VALUE); }
-
-  inline void make_inert (void)
-  {
-    if (get_unsafe () == HB_REFERENCE_COUNT_UNCHANGABLE_VALUE)
-      return;
-    ref_count.set_unsafe (HB_REFERENCE_COUNT_UNREFFABLE_VALUE);
-  }
-  inline void undo_inert (void)
-  {
-    if (get_unsafe () == HB_REFERENCE_COUNT_UNCHANGABLE_VALUE)
-      return;
-    assert (get_unsafe () == HB_REFERENCE_COUNT_UNREFFABLE_VALUE);
-    ref_count.set_unsafe (1);
-  }
-
-  inline bool is_inert (void) const { return ref_count.get_unsafe () < 0; }
+  inline void finish (void) { ref_count.set_unsafe (HB_REFERENCE_COUNT_POISON_VALUE); }
+
+  inline bool is_inert (void) const { return ref_count.get_unsafe () == HB_REFERENCE_COUNT_INERT_VALUE; }
   inline bool is_valid (void) const { return ref_count.get_unsafe () > 0; }
 };
 
@@ -161,16 +146,6 @@ static inline bool hb_object_is_valid (const Type *obj)
   return likely (obj->header.ref_count.is_valid ());
 }
 template <typename Type>
-static inline void hb_object_make_inert (Type *obj)
-{
-  obj->header.ref_count.make_inert ();
-}
-template <typename Type>
-static inline void hb_object_undo_inert (Type *obj)
-{
-  obj->header.ref_count.undo_inert ();
-}
-template <typename Type>
 static inline Type *hb_object_reference (Type *obj)
 {
   hb_object_trace (obj, HB_FUNC);

src/hb-ot-font.cc

@@ -663,7 +663,6 @@ static hb_font_funcs_t *static_ot_funcs = nullptr;
 static
 void free_static_ot_funcs (void)
 {
-  hb_object_undo_inert (static_ot_funcs);
   hb_font_funcs_destroy (static_ot_funcs);
 }
 #endif
@@ -694,10 +693,8 @@ retry:
     hb_font_funcs_set_glyph_from_name_func (funcs, hb_ot_get_glyph_from_name, nullptr, nullptr);
 
     hb_font_funcs_make_immutable (funcs);
-    hb_object_make_inert (funcs);
 
     if (!hb_atomic_ptr_cmpexch (&static_ot_funcs, nullptr, funcs)) {
-      hb_object_undo_inert (funcs);
       hb_font_funcs_destroy (funcs);
       goto retry;
     }

src/hb-ucdn.cc

@@ -237,7 +237,6 @@ static hb_unicode_funcs_t *static_ucdn_funcs = nullptr;
 static
 void free_static_ucdn_funcs (void)
 {
-  hb_object_undo_inert (static_ucdn_funcs);
   hb_unicode_funcs_destroy (static_ucdn_funcs);
 }
 #endif
@@ -259,10 +258,8 @@ retry:
 #undef HB_UNICODE_FUNC_IMPLEMENT
 
     hb_unicode_funcs_make_immutable (funcs);
-    hb_object_make_inert (funcs);
 
     if (!hb_atomic_ptr_cmpexch (&static_ucdn_funcs, nullptr, funcs)) {
-      hb_object_undo_inert (funcs);
       hb_unicode_funcs_destroy (funcs);
       goto retry;
     }