From 74f1d896f2479500d65649cf3ec86dd201f0663a Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Tue, 10 May 2011 19:39:32 -0400
Subject: [PATCH] Add hb_font_make/is_immutable()

---
 src/hb-font-private.hh |  2 ++
 src/hb-font.cc         | 26 +++++++++++++++++++++++---
 src/hb-font.h          |  6 ++++++
 test/test-object.c     |  2 +-
 4 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/hb-font-private.hh b/src/hb-font-private.hh
index 683eab5..cd74e08 100644
--- a/src/hb-font-private.hh
+++ b/src/hb-font-private.hh
@@ -80,6 +80,8 @@ struct _hb_face_t {
 struct _hb_font_t {
   hb_object_header_t header;
 
+  hb_bool_t immutable;
+
   hb_face_t *face;
 
   unsigned int x_scale;
diff --git a/src/hb-font.cc b/src/hb-font.cc
index 1e7734b..f04fadb 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -448,6 +448,8 @@ hb_face_get_upem (hb_face_t *face)
 static hb_font_t _hb_font_nil = {
   HB_OBJECT_HEADER_STATIC,
 
+  TRUE,  /* immutable */
+
   &_hb_face_nil,
 
   0, /* x_scale */
@@ -514,6 +516,21 @@ hb_font_get_user_data (hb_font_t          *font,
   return hb_object_get_user_data (font, key);
 }
 
+void
+hb_font_make_immutable (hb_font_t *font)
+{
+  if (hb_object_is_inert (font))
+    return;
+
+  font->immutable = true;
+}
+
+hb_bool_t
+hb_font_is_immutable (hb_font_t *font)
+{
+  return font->immutable;
+}
+
 
 hb_face_t *
 hb_font_get_face (hb_font_t *font)
@@ -528,7 +545,7 @@ hb_font_set_funcs (hb_font_t         *font,
 		   void              *user_data,
 		   hb_destroy_func_t  destroy)
 {
-  if (hb_object_is_inert (font))
+  if (font->immutable)
     return;
 
   if (font->destroy)
@@ -550,6 +567,9 @@ hb_font_unset_funcs (hb_font_t          *font,
 		     void              **user_data,
 		     hb_destroy_func_t  *destroy)
 {
+  if (font->immutable)
+    return;
+
   /* None of the input arguments can be NULL. */
 
   *klass = font->klass;
@@ -569,7 +589,7 @@ hb_font_set_scale (hb_font_t *font,
 		   int x_scale,
 		   int y_scale)
 {
-  if (hb_object_is_inert (font))
+  if (font->immutable)
     return;
 
   font->x_scale = x_scale;
@@ -590,7 +610,7 @@ hb_font_set_ppem (hb_font_t *font,
 		  unsigned int x_ppem,
 		  unsigned int y_ppem)
 {
-  if (hb_object_is_inert (font))
+  if (font->immutable)
     return;
 
   font->x_ppem = x_ppem;
diff --git a/src/hb-font.h b/src/hb-font.h
index e8e344d..fc3518c 100644
--- a/src/hb-font.h
+++ b/src/hb-font.h
@@ -225,6 +225,12 @@ void *
 hb_font_get_user_data (hb_font_t          *font,
 		       hb_user_data_key_t *key);
 
+void
+hb_font_make_immutable (hb_font_t *font);
+
+hb_bool_t
+hb_font_is_immutable (hb_font_t *font);
+
 
 hb_face_t *
 hb_font_get_face (hb_font_t *font);
diff --git a/test/test-object.c b/test/test-object.c
index 6937280..1abe65c 100644
--- a/test/test-object.c
+++ b/test/test-object.c
@@ -161,8 +161,8 @@ static const object_t objects[] =
 {
   OBJECT_WITHOUT_IMMUTABILITY (buffer),
   OBJECT_WITHOUT_IMMUTABILITY (face),
-  OBJECT_WITHOUT_IMMUTABILITY (font),
   OBJECT_WITH_IMMUTABILITY (blob),
+  OBJECT_WITH_IMMUTABILITY (font),
   OBJECT_WITH_IMMUTABILITY (font_funcs),
   OBJECT_WITH_IMMUTABILITY (unicode_funcs)
 };
-- 
2.7.4