From 08ed9e3f779253e3b5f01c38d44d0e5db2d5e7aa Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sun, 28 Jun 2020 20:48:48 -0700
Subject: [PATCH] [buffer/set/map] Move immutable check only to C API boundary

The immutable objects are a concept only enforced by the C API.
So move checks only to that region.

This does assume that the rest of the code is careful not getting
into these internal methods on immutable objects, which something
we do, but have no way of enforcing (currently).

.
---
 src/hb-buffer.cc | 21 ++++++---------------
 src/hb-map.cc    |  3 +++
 src/hb-map.hh    |  4 ----
 src/hb-set.cc    |  3 +++
 src/hb-set.hh    |  5 -----
 5 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 3c54f7243..0e293f6b5 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -218,9 +218,6 @@ hb_buffer_t::get_scratch_buffer (unsigned int *size)
 void
 hb_buffer_t::reset ()
 {
-  if (unlikely (hb_object_is_immutable (this)))
-    return;
-
   hb_unicode_funcs_destroy (unicode);
   unicode = hb_unicode_funcs_reference (hb_unicode_funcs_get_default ());
   flags = HB_BUFFER_FLAG_DEFAULT;
@@ -233,9 +230,6 @@ hb_buffer_t::reset ()
 void
 hb_buffer_t::clear ()
 {
-  if (unlikely (hb_object_is_immutable (this)))
-    return;
-
   hb_segment_properties_t default_props = HB_SEGMENT_PROPERTIES_DEFAULT;
   props = default_props;
   scratch_flags = HB_BUFFER_SCRATCH_FLAG_DEFAULT;
@@ -290,9 +284,6 @@ hb_buffer_t::add_info (const hb_glyph_info_t &glyph_info)
 void
 hb_buffer_t::remove_output ()
 {
-  if (unlikely (hb_object_is_immutable (this)))
-    return;
-
   have_output = false;
   have_positions = false;
 
@@ -303,9 +294,6 @@ hb_buffer_t::remove_output ()
 void
 hb_buffer_t::clear_output ()
 {
-  if (unlikely (hb_object_is_immutable (this)))
-    return;
-
   have_output = true;
   have_positions = false;
 
@@ -316,9 +304,6 @@ hb_buffer_t::clear_output ()
 void
 hb_buffer_t::clear_positions ()
 {
-  if (unlikely (hb_object_is_immutable (this)))
-    return;
-
   have_output = false;
   have_positions = true;
 
@@ -1226,6 +1211,9 @@ hb_buffer_get_invisible_glyph (hb_buffer_t    *buffer)
 void
 hb_buffer_reset (hb_buffer_t *buffer)
 {
+  if (unlikely (hb_object_is_immutable (buffer)))
+    return;
+
   buffer->reset ();
 }
 
@@ -1241,6 +1229,9 @@ hb_buffer_reset (hb_buffer_t *buffer)
 void
 hb_buffer_clear_contents (hb_buffer_t *buffer)
 {
+  if (unlikely (hb_object_is_immutable (buffer)))
+    return;
+
   buffer->clear ();
 }
 
diff --git a/src/hb-map.cc b/src/hb-map.cc
index aabf713d5..f115da2bb 100644
--- a/src/hb-map.cc
+++ b/src/hb-map.cc
@@ -253,6 +253,9 @@ hb_map_has (const hb_map_t *map,
 void
 hb_map_clear (hb_map_t *map)
 {
+  if (unlikely (hb_object_is_immutable (map)))
+    return;
+
   return map->clear ();
 }
 
diff --git a/src/hb-map.hh b/src/hb-map.hh
index 92c1bd67e..82fa3ccf8 100644
--- a/src/hb-map.hh
+++ b/src/hb-map.hh
@@ -97,8 +97,6 @@ struct hb_hashmap_t
 
   void reset ()
   {
-    if (unlikely (hb_object_is_immutable (this)))
-      return;
     successful = true;
     clear ();
   }
@@ -171,8 +169,6 @@ struct hb_hashmap_t
 
   void clear ()
   {
-    if (unlikely (hb_object_is_immutable (this)))
-      return;
     if (items)
       for (auto &_ : hb_iter (items, mask + 1))
 	_.clear ();
diff --git a/src/hb-set.cc b/src/hb-set.cc
index 55e3b9025..86bf70034 100644
--- a/src/hb-set.cc
+++ b/src/hb-set.cc
@@ -183,6 +183,9 @@ hb_set_allocation_successful (const hb_set_t  *set)
 void
 hb_set_clear (hb_set_t *set)
 {
+  if (unlikely (hb_object_is_immutable (set)))
+    return;
+
   set->clear ();
 }
 
diff --git a/src/hb-set.hh b/src/hb-set.hh
index c524b5d31..3b100f609 100644
--- a/src/hb-set.hh
+++ b/src/hb-set.hh
@@ -256,17 +256,12 @@ struct hb_set_t
 
   void reset ()
   {
-    if (unlikely (hb_object_is_immutable (this)))
-      return;
     successful = true;
     clear ();
   }
 
   void clear ()
   {
-    if (unlikely (hb_object_is_immutable (this)))
-      return;
-
     if (resize (0))
       population = 0;
   }