From 56e3868b52ef6e85d6495d28bae57dcc5746d1db Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sat, 26 Nov 2022 13:14:23 -0700
Subject: [PATCH] [layout/buffer-message] Print feature name in lookup buffer
 messages

---
 src/hb-ot-layout.cc | 6 +++---
 src/hb-ot-map.cc    | 7 +++++--
 src/hb-ot-map.hh    | 4 +++-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 2bdb5e1c7..1ee23f0ce 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -1913,7 +1913,7 @@ inline void hb_ot_map_t::apply (const Proxy &proxy,
       auto &lookup = lookups[table_index][i];
 
       unsigned int lookup_index = lookup.index;
-      if (!buffer->message (font, "start lookup %d", lookup_index)) continue;
+      if (!buffer->message (font, "start lookup %d feature %c%c%c%c", lookup_index, HB_UNTAG (lookup.feature_tag))) continue;
 
       /* c.digest is a digest of all the current glyphs in the buffer
        * (plus some past glyphs).
@@ -1933,9 +1933,9 @@ inline void hb_ot_map_t::apply (const Proxy &proxy,
 			     proxy.accels[lookup_index]);
       }
       else
-	(void) buffer->message (font, "skipped lookup %d because no glyph matches", lookup_index);
+	(void) buffer->message (font, "skipped lookup %d feature %c%c%c%c because no glyph matches", lookup_index, HB_UNTAG (lookup.feature_tag));
 
-      (void) buffer->message (font, "end lookup %d", lookup_index);
+      (void) buffer->message (font, "end lookup %d feature %c%c%c%c", lookup_index, HB_UNTAG (lookup.feature_tag));
     }
 
     if (stage->pause_func)
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 3c6688f5c..028f31c8d 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -133,7 +133,8 @@ hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
 				  bool          auto_zwnj,
 				  bool          auto_zwj,
 				  bool          random,
-				  bool          per_syllable)
+				  bool          per_syllable,
+				  hb_tag_t      feature_tag)
 {
   unsigned int lookup_indices[32];
   unsigned int offset, len;
@@ -162,6 +163,7 @@ hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
       lookup->auto_zwj = auto_zwj;
       lookup->random = random;
       lookup->per_syllable = per_syllable;
+      lookup->feature_tag = feature_tag;
     }
 
     offset += len;
@@ -339,7 +341,8 @@ hb_ot_map_builder_t::compile (hb_ot_map_t                  &m,
 		       feature.auto_zwnj,
 		       feature.auto_zwj,
 		       feature.random,
-		       feature.per_syllable);
+		       feature.per_syllable,
+		       feature.tag);
       }
 
       /* Sort lookups and merge duplicates */
diff --git a/src/hb-ot-map.hh b/src/hb-ot-map.hh
index 53cf16fd4..5122c4e56 100644
--- a/src/hb-ot-map.hh
+++ b/src/hb-ot-map.hh
@@ -69,6 +69,7 @@ struct hb_ot_map_t
     unsigned short random : 1;
     unsigned short per_syllable : 1;
     hb_mask_t mask;
+    hb_tag_t feature_tag;
 
     HB_INTERNAL static int cmp (const void *pa, const void *pb)
     {
@@ -241,7 +242,8 @@ struct hb_ot_map_builder_t
 				bool          auto_zwnj = true,
 				bool          auto_zwj = true,
 				bool          random = false,
-				bool          per_syllable = false);
+				bool          per_syllable = false,
+				hb_tag_t      feature_tag = HB_TAG_NONE);
 
   struct feature_info_t {
     hb_tag_t tag;