Switch cache-long-scans to t by default.

 src/xdisp.c (message_dolog): Make sure the *Messages* buffer has its
 cache-long-scans disabled, since we don't want to call
 prepare_to_modify_buffer (in insert_1_both) for each message we
 display.
 src/buffer.h (bset_cache_long_scans): New INLINE function, moved
 from buffer.c.  Improve commentary to the buffer field setter
 functions.
 src/buffer.c (bset_cache_long_scans): Static function deleted.
 Improve commentary to the buffer field setter functions.
 (init_buffer_once): Default for cache-long-scans changed to t.
 (Bug#15797)

4 files changed, 27 insertions, 8 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9bf71b9ce21..fdb4b24233f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,19 @@
+2013-11-08  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (message_dolog): Make sure the *Messages* buffer has its
+        cache-long-scans disabled, since we don't want to call
+        prepare_to_modify_buffer (in insert_1_both) for each message we
+        display.
+
+        * buffer.h (bset_cache_long_scans): New INLINE function, moved
+        from buffer.c.  Improve commentary to the buffer field setter
+        functions.
+
+        * buffer.c (bset_cache_long_scans): Static function deleted.
+        Improve commentary to the buffer field setter functions.
+        (init_buffer_once): Default for cache-long-scans changed to t.
+        (Bug#15797)
+
 2013-11-08  Paul Eggert  <eggert@cs.ucla.edu>
 
         * chartab.c (make_sub_char_table): Fix size typo (Bug#15825).
diff --git a/src/buffer.c b/src/buffer.c
index d3288ad0429..7a424ffd901 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -154,7 +154,8 @@ CHECK_OVERLAY (Lisp_Object x)
   CHECK_TYPE (OVERLAYP (x), Qoverlayp, x);
 }
 
-/* These setters are used only in this file, so they can be private.  */
+/* These setters are used only in this file, so they can be private.
+   The public setters are inline functions defined in buffer.h.  */
 static void
 bset_abbrev_mode (struct buffer *b, Lisp_Object val)
 {
@@ -201,11 +202,6 @@ bset_buffer_file_coding_system (struct buffer *b, Lisp_Object val)
   b->INTERNAL_FIELD (buffer_file_coding_system) = val;
 }
 static void
-bset_cache_long_scans (struct buffer *b, Lisp_Object val)
-{
-  b->INTERNAL_FIELD (cache_long_scans) = val;
-}
-static void
 bset_case_fold_search (struct buffer *b, Lisp_Object val)
 {
   b->INTERNAL_FIELD (case_fold_search) = val;
@@ -5185,7 +5181,7 @@ init_buffer_once (void)
   bset_buffer_file_coding_system (&buffer_defaults, Qnil);
   XSETFASTINT (BVAR (&buffer_defaults, fill_column), 70);
   XSETFASTINT (BVAR (&buffer_defaults, left_margin), 0);
-  bset_cache_long_scans (&buffer_defaults, Qnil);
+  bset_cache_long_scans (&buffer_defaults, Qt);
   bset_file_truename (&buffer_defaults, Qnil);
   XSETFASTINT (BVAR (&buffer_defaults, display_count), 0);
   XSETFASTINT (BVAR (&buffer_defaults, left_margin_cols), 0);
diff --git a/src/buffer.h b/src/buffer.h
index a36c0d13c9e..f39e3d33185 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -871,13 +871,19 @@ struct buffer
 };
 
 /* Most code should use these functions to set Lisp fields in struct
-   buffer.  */
+   buffer.  (Some setters that are priviate to a single .c file are
+   defined as static in those files.)  */
 INLINE void
 bset_bidi_paragraph_direction (struct buffer *b, Lisp_Object val)
 {
   b->INTERNAL_FIELD (bidi_paragraph_direction) = val;
 }
 INLINE void
+bset_cache_long_scans (struct buffer *b, Lisp_Object val)
+{
+  b->INTERNAL_FIELD (cache_long_scans) = val;
+}
+INLINE void
 bset_case_canon_table (struct buffer *b, Lisp_Object val)
 {
   b->INTERNAL_FIELD (case_canon_table) = val;
diff --git a/src/xdisp.c b/src/xdisp.c
index 021147ecba8..d6269f24413 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -9488,6 +9488,7 @@ message_dolog (const char *m, ptrdiff_t nbytes, bool nlflag, bool multibyte)
       }
 
       bset_undo_list (current_buffer, Qt);
+      bset_cache_long_scans (current_buffer, Qnil);
 
       oldpoint = message_dolog_marker1;
       set_marker_restricted_both (oldpoint, Qnil, PT, PT_BYTE);