From 06175b71433bc42edc07d342e6354035e37fb5fd Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Tue, 15 Jun 2021 14:33:27 -0600
Subject: [PATCH] Remove unneeded buffer clear_output / remove_output calls

Made sure clear_output is always paired with swap_buffers.
Trying to see if we can move towards RAII-like buffer iterators
instead of the buffer keeping an iterator internally.
---
 src/hb-buffer.cc    | 10 ----------
 src/hb-buffer.hh    |  1 -
 src/hb-ot-layout.cc | 12 ++++--------
 src/hb-ot-shape.cc  |  3 +--
 4 files changed, 5 insertions(+), 21 deletions(-)

diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index b125e1cea..5e728b05a 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -281,16 +281,6 @@ hb_buffer_t::add_info (const hb_glyph_info_t &glyph_info)
 }
 
 
-void
-hb_buffer_t::remove_output ()
-{
-  have_output = false;
-  have_positions = false;
-
-  out_len = 0;
-  out_info = info;
-}
-
 void
 hb_buffer_t::clear_output ()
 {
diff --git a/src/hb-buffer.hh b/src/hb-buffer.hh
index 33d6e6c66..67429df23 100644
--- a/src/hb-buffer.hh
+++ b/src/hb-buffer.hh
@@ -209,7 +209,6 @@ struct hb_buffer_t
   HB_INTERNAL void guess_segment_properties ();
 
   HB_INTERNAL void swap_buffers ();
-  HB_INTERNAL void remove_output ();
   HB_INTERNAL void clear_output ();
   HB_INTERNAL void clear_positions ();
 
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 97d2971be..98b4aa641 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -1857,8 +1857,9 @@ apply_string (OT::hb_ot_apply_context_t *c,
   if (likely (!lookup.is_reverse ()))
   {
     /* in/out forward substitution/positioning */
-    if (Proxy::table_index == 0u)
+    if (!Proxy::inplace)
       buffer->clear_output ();
+
     buffer->idx = 0;
 
     bool ret;
@@ -1874,10 +1875,7 @@ apply_string (OT::hb_ot_apply_context_t *c,
   else
   {
     /* in-place backward substitution/positioning */
-    if (Proxy::table_index == 0u)
-      buffer->remove_output ();
     buffer->idx = buffer->len - 1;
-
     apply_backward (c, accel);
   }
 }
@@ -1893,7 +1891,8 @@ inline void hb_ot_map_t::apply (const Proxy &proxy,
   OT::hb_ot_apply_context_t c (table_index, font, buffer);
   c.set_recurse_func (Proxy::Lookup::apply_recurse_func);
 
-  for (unsigned int stage_index = 0; stage_index < stages[table_index].length; stage_index++) {
+  for (unsigned int stage_index = 0; stage_index < stages[table_index].length; stage_index++)
+  {
     const stage_map_t *stage = &stages[table_index][stage_index];
     for (; i < stage->last_lookup; i++)
     {
@@ -1915,10 +1914,7 @@ inline void hb_ot_map_t::apply (const Proxy &proxy,
     }
 
     if (stage->pause_func)
-    {
-      buffer->clear_output ();
       stage->pause_func (plan, font, buffer);
-    }
   }
 }
 
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 4fe148d67..e27094a1d 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -551,6 +551,7 @@ hb_insert_dotted_circle (hb_buffer_t *buffer, hb_font_t *font)
   info.cluster = buffer->cur().cluster;
   info.mask = buffer->cur().mask;
   (void) buffer->output_info (info);
+
   buffer->swap_buffers ();
 }
 
@@ -1127,8 +1128,6 @@ hb_ot_shape_internal (hb_ot_shape_context_t *c)
 
   _hb_buffer_allocate_unicode_vars (c->buffer);
 
-  c->buffer->clear_output ();
-
   hb_ot_shape_initialize_masks (c);
   hb_set_unicode_props (c->buffer);
   hb_insert_dotted_circle (c->buffer, c->font);