From 3e2c4cd143d51c66198dd606e18015eeae42f3ec Mon Sep 17 00:00:00 2001
From: Matt Armstrong <matt@rfc20.org>
Date: Tue, 8 Nov 2022 15:00:18 -0800
Subject: [PATCH] Add itree_empty_p for clarity and reduced coupling

* src/itree.h (itree_empty_p): New predicate.
* src/buffer.h (buffer_has_overlays): Call it.
* src/pdumper.c (dump_buffer): ditto.
* src/alloc.c (mark_buffer): ditto.
---
 src/alloc.c   | 2 +-
 src/buffer.h  | 3 +--
 src/itree.h   | 9 +++++++++
 src/pdumper.c | 2 +-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/alloc.c b/src/alloc.c
index 0653f2e0cc..526a25393f 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6553,7 +6553,7 @@ mark_buffer (struct buffer *buffer)
   if (!BUFFER_LIVE_P (buffer))
       mark_object (BVAR (buffer, undo_list));
 
-  if (buffer->overlays)
+  if (!itree_empty_p (buffer->overlays))
     mark_overlays (buffer->overlays->root);
 
   /* If this is an indirect buffer, mark its base buffer.  */
diff --git a/src/buffer.h b/src/buffer.h
index dded0cd98c..9ead875bcf 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -1277,8 +1277,7 @@ set_buffer_intervals (struct buffer *b, INTERVAL i)
 INLINE bool
 buffer_has_overlays (void)
 {
-  return current_buffer->overlays
-         && (current_buffer->overlays->root != NULL);
+  return !itree_empty_p (current_buffer->overlays);
 }
 
 /* Functions for accessing a character or byte,
diff --git a/src/itree.h b/src/itree.h
index 291fa53fd3..248ea9b84d 100644
--- a/src/itree.h
+++ b/src/itree.h
@@ -25,6 +25,8 @@ #define ITREE_H
 
 #include "lisp.h"
 
+INLINE_HEADER_BEGIN
+
 /* The tree and node structs are mainly here, so they can be
    allocated.
 
@@ -114,6 +116,11 @@ #define ITREE_H
 				   ptrdiff_t, ptrdiff_t);
 extern struct itree_tree *itree_create (void);
 extern void itree_destroy (struct itree_tree *);
+INLINE bool
+itree_empty_p (struct itree_tree *tree)
+{
+  return !tree || !tree->root;
+}
 extern intmax_t itree_size (struct itree_tree *);
 extern void itree_clear (struct itree_tree *);
 extern void itree_insert (struct itree_tree *, struct itree_node *,
@@ -178,4 +185,6 @@ #define ITREE_FOREACH(n, t, beg, end, order)                        \
 #define ITREE_FOREACH_NARROW(beg, end) \
   itree_iterator_narrow (itree_iter_, beg, end)
 
+INLINE_HEADER_END
+
 #endif
diff --git a/src/pdumper.c b/src/pdumper.c
index fedcd3e404..35e86d2b50 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -2863,7 +2863,7 @@ dump_buffer (struct dump_context *ctx, const struct buffer *in_buffer)
   DUMP_FIELD_COPY (out, buffer, inhibit_buffer_hooks);
   DUMP_FIELD_COPY (out, buffer, long_line_optimizations_p);
 
-  if (buffer->overlays && buffer->overlays->root != NULL)
+  if (!itree_empty_p (buffer->overlays))
     /* We haven't implemented the code to dump overlays.  */
     emacs_abort ();
   else
-- 
2.35.1