[pango] Handle realloc failure in the buffer

[Behdad Esfahbod <behdad src gnome org>]

commit 6b522430ad65fe047b077f9cc3990a97e8869e23
Author: Behdad Esfahbod <behdad behdad org>
Date:   Mon Mar 14 17:05:39 2011 -0300

    Handle realloc failure in the buffer
    
    Ported from http://cgit.freedesktop.org/harfbuzz/commit/?id=a6a79df5fe2e
    by Karl Tomlinson <karlt+ karlt net>

 pango/opentype/hb-buffer-private.h |    1 +
 pango/opentype/hb-buffer.c         |   70 +++++++++++++++++++++---------------
 pango/opentype/hb-buffer.h         |    2 +-
 3 files changed, 43 insertions(+), 30 deletions(-)
---
diff --git a/pango/opentype/hb-buffer-private.h b/pango/opentype/hb-buffer-private.h
index 45cdc4d..f194786 100644
--- a/pango/opentype/hb-buffer-private.h
+++ b/pango/opentype/hb-buffer-private.h
@@ -72,6 +72,7 @@ struct _hb_buffer_t {
   unsigned int allocated;
 
   hb_bool_t    have_output; /* weather we have an output buffer going on */
+  hb_bool_t    in_error; /* Allocation failed */
   unsigned int in_length;
   unsigned int out_length;
   unsigned int in_pos;
diff --git a/pango/opentype/hb-buffer.c b/pango/opentype/hb-buffer.c
index 93b51e5..e9788ad 100644
--- a/pango/opentype/hb-buffer.c
+++ b/pango/opentype/hb-buffer.c
@@ -52,23 +52,21 @@ static hb_buffer_t _hb_buffer_nil = {
  * in_string and out_string.
  */
 
-/* XXX err handling */
-
 /* Internal API */
 
-static void
+static hb_bool_t
 hb_buffer_ensure_separate (hb_buffer_t *buffer, unsigned int size)
 {
-  hb_buffer_ensure (buffer, size);
+  if (HB_UNLIKELY (!hb_buffer_ensure (buffer, size))) return FALSE;
   if (buffer->out_string == buffer->in_string)
   {
     assert (buffer->have_output);
-    if (!buffer->positions)
-      buffer->positions = calloc (buffer->allocated, sizeof (buffer->positions[0]));
 
     buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
     memcpy (buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]));
   }
+
+  return TRUE;
 }
 
 /* Public API */
@@ -114,6 +112,7 @@ void
 hb_buffer_clear (hb_buffer_t *buffer)
 {
   buffer->have_output = FALSE;
+  buffer->in_error = FALSE;
   buffer->in_length = 0;
   buffer->out_length = 0;
   buffer->in_pos = 0;
@@ -122,32 +121,42 @@ hb_buffer_clear (hb_buffer_t *buffer)
   buffer->max_lig_id = 0;
 }
 
-void
+hb_bool_t
 hb_buffer_ensure (hb_buffer_t *buffer, unsigned int size)
 {
-  unsigned int new_allocated = buffer->allocated;
-
-  if (size > new_allocated)
+  if (HB_UNLIKELY (size > buffer->allocated))
   {
+    unsigned int new_allocated = buffer->allocated;
+    hb_internal_glyph_position_t *new_pos;
+    hb_internal_glyph_info_t *new_info;
+    hb_bool_t separate_out;
+
+    if (HB_UNLIKELY (buffer->in_error))
+      return FALSE;
+
+    separate_out = buffer->out_string != buffer->in_string;
+
     while (size > new_allocated)
       new_allocated += (new_allocated >> 1) + 8;
 
-    if (buffer->positions)
-      buffer->positions = realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));
+    new_pos = (hb_internal_glyph_position_t *) realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));
+    new_info = (hb_internal_glyph_info_t *) realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
 
-    if (buffer->out_string != buffer->in_string)
-    {
-      buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
-      buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
-    }
-    else
-    {
-      buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
-      buffer->out_string = buffer->in_string;
-    }
+    if (HB_UNLIKELY (!new_pos || !new_info))
+      buffer->in_error = TRUE;
+
+    if (HB_LIKELY (new_pos))
+      buffer->positions = new_pos;
 
-    buffer->allocated = new_allocated;
+    if (HB_LIKELY (new_info))
+      buffer->in_string = new_info;
+
+    buffer->out_string = separate_out ? (hb_internal_glyph_info_t *) buffer->positions : buffer->in_string;
+    if (HB_LIKELY (!buffer->in_error))
+      buffer->allocated = new_allocated;
   }
+
+  return HB_LIKELY (!buffer->in_error);
 }
 
 void
@@ -158,7 +167,7 @@ hb_buffer_add_glyph (hb_buffer_t    *buffer,
 {
   hb_internal_glyph_info_t *glyph;
 
-  hb_buffer_ensure (buffer, buffer->in_length + 1);
+  if (HB_UNLIKELY (!hb_buffer_ensure (buffer, buffer->in_length + 1))) return;
 
   glyph = &buffer->in_string[buffer->in_length];
   glyph->codepoint = codepoint;
@@ -213,6 +222,8 @@ _hb_buffer_swap (hb_buffer_t *buffer)
 
   assert (buffer->have_output);
 
+  if (HB_UNLIKELY (buffer->in_error)) return;
+
   if (buffer->out_string != buffer->in_string)
   {
     hb_internal_glyph_info_t *tmp_string;
@@ -265,7 +276,8 @@ _hb_buffer_add_output_glyphs (hb_buffer_t *buffer,
   if (buffer->out_string != buffer->in_string ||
       buffer->out_pos + num_out > buffer->in_pos + num_in)
   {
-    hb_buffer_ensure_separate (buffer, buffer->out_pos + num_out);
+    if (HB_UNLIKELY (!hb_buffer_ensure_separate (buffer, buffer->out_pos + num_out)))
+        return;
   }
 
   mask = buffer->in_string[buffer->in_pos].mask;
@@ -302,7 +314,7 @@ _hb_buffer_add_output_glyph (hb_buffer_t *buffer,
 
   if (buffer->out_string != buffer->in_string)
   {
-    hb_buffer_ensure (buffer, buffer->out_pos + 1);
+    if (HB_UNLIKELY (!hb_buffer_ensure (buffer, buffer->out_pos + 1))) return;
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
   }
   else if (buffer->out_pos != buffer->in_pos)
@@ -332,7 +344,7 @@ _hb_buffer_next_glyph (hb_buffer_t *buffer)
 
   if (buffer->out_string != buffer->in_string)
   {
-    hb_buffer_ensure (buffer, buffer->out_pos + 1);
+    if (HB_UNLIKELY (!hb_buffer_ensure (buffer, buffer->out_pos + 1))) return;
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
   }
   else if (buffer->out_pos != buffer->in_pos)
diff --git a/pango/opentype/hb-buffer.h b/pango/opentype/hb-buffer.h
index b030ba9..aaf6694 100644
--- a/pango/opentype/hb-buffer.h
+++ b/pango/opentype/hb-buffer.h
@@ -94,7 +94,7 @@ hb_buffer_clear (hb_buffer_t *buffer);
 void
 hb_buffer_clear_positions (hb_buffer_t *buffer);
 
-void
+hb_bool_t
 hb_buffer_ensure (hb_buffer_t  *buffer,
 		  unsigned int  size);