From b05e5d9a7998529ffd0e34f3b8d3ae5bf4c200eb Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Mon, 15 Mar 2021 14:08:08 -0600
Subject: [PATCH] [buffer] HB_NODISCARD next_glyphs()

---
 src/hb-buffer.cc             | 2 +-
 src/hb-buffer.hh             | 2 +-
 src/hb-ot-shape-normalize.cc | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 8da090ad4..494bf395e 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -319,7 +319,7 @@ hb_buffer_t::swap_buffers ()
   if (unlikely (!successful)) return;
 
   assert (idx <= len);
-  next_glyphs (len - idx);
+  if (unlikely (!next_glyphs (len - idx))) return;
 
   assert (have_output);
   have_output = false;
diff --git a/src/hb-buffer.hh b/src/hb-buffer.hh
index 0582d3a21..2e43f2e69 100644
--- a/src/hb-buffer.hh
+++ b/src/hb-buffer.hh
@@ -280,7 +280,7 @@ struct hb_buffer_t
   }
   /* Copies n glyphs at idx to output and advance idx.
    * If there's no output, just advance idx. */
-  bool next_glyphs (unsigned int n)
+  HB_NODISCARD bool next_glyphs (unsigned int n)
   {
     if (have_output)
     {
diff --git a/src/hb-ot-shape-normalize.cc b/src/hb-ot-shape-normalize.cc
index 776e29902..bce9dcf5d 100644
--- a/src/hb-ot-shape-normalize.cc
+++ b/src/hb-ot-shape-normalize.cc
@@ -348,7 +348,7 @@ _hb_ot_shape_normalize (const hb_ot_shape_plan_t *plan,
 						      sizeof (buffer->info[0]),
 						      &buffer->cur().glyph_index(),
 						      sizeof (buffer->info[0]));
-	buffer->next_glyphs (done);
+	if (unlikely (!buffer->next_glyphs (done))) break;
       }
       while (buffer->idx < end && buffer->successful)
 	decompose_current_character (&c, might_short_circuit);