(with_echo_area_buffer): Delete WHICH < 0 case.

(set_message): Call with_echo_area_buffer with WHICH = 0.
(set_message_1): Erase the echo area buffer first thing.
(echo_area_display): Don't clear echo_message_buffer.

2 files changed, 22 insertions, 22 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b8ebd3f8ba2..ffcfdebcab1 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2005-04-16  Richard M. Stallman  <rms@gnu.org>
+
+        * xdisp.c (with_echo_area_buffer): Delete WHICH < 0 case.
+        (set_message): Call with_echo_area_buffer with WHICH = 0.
+        (set_message_1): Erase the echo area buffer first thing.
+        (echo_area_display): Don't clear echo_message_buffer.
+
 2005-04-16  YAMAMOTO Mitsuharu  <mituharu@math.s.chiba-u.ac.jp>
 
         * Makefile.in (mac.o): Depend on charset.h and coding.h.
diff --git a/src/xdisp.c b/src/xdisp.c
index e3e1048aaea..4a6bc3ffeb7 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -567,12 +567,21 @@ Lisp_Object Vmessage_log_max;
 
 static Lisp_Object Vmessages_buffer_name;
 
-/* Current, index 0, and last displayed echo area message.  Either
-   buffers from echo_buffers, or nil to indicate no message.  */
+/* Index 0 is the buffer that holds the current (desired) echo area message,
+   or nil if none is desired right now.
+
+   Index 1 is the buffer that holds the previously displayed echo area message,
+   or nil to indicate no message.  This is normally what's on the screen now.
+
+   These two can point to the same buffer.  That happens when the last
+   message output by the user (or made by echoing) has been displayed.  */
 
 Lisp_Object echo_area_buffer[2];
 
-/* The buffers referenced from echo_area_buffer.  */
+/* Permanent pointers to the two buffers that are used for echo area
+   purposes.  Once the two buffers are made, and their pointers are
+   placed here, these two slots remain unchanged unless those buffers
+   need to be created afresh.  */
 
 static Lisp_Object echo_buffer[2];
 
@@ -7217,10 +7226,6 @@ ensure_echo_area_buffers ()
    WHICH > 0 means use echo_area_buffer[1].  If that is nil, choose a
    suitable buffer from echo_buffer[] and clear it.
 
-   If WHICH < 0, set echo_area_buffer[1] to echo_area_buffer[0], so
-   that the current message becomes the last displayed one, make
-   choose a suitable buffer for echo_area_buffer[0], and clear it.
-
    Value is what FN returns.  */
 
 static int
@@ -7245,17 +7250,6 @@ with_echo_area_buffer (w, which, fn, a1, a2, a3, a4)
     this_one = 0, the_other = 1;
   else if (which > 0)
     this_one = 1, the_other = 0;
-  else
-    {
-      this_one = 0, the_other = 1;
-      clear_buffer_p = 1;
-
-      /* We need a fresh one in case the current echo buffer equals
-         the one containing the last displayed echo area message.  */
-      if (!NILP (echo_area_buffer[this_one])
-          && EQ (echo_area_buffer[this_one], echo_area_buffer[the_other]))
-        echo_area_buffer[this_one] = Qnil;
-    }
 
   /* Choose a suitable buffer from echo_buffer[] is we don't
      have one.  */
@@ -7875,7 +7869,7 @@ set_message (s, string, nbytes, multibyte_p)
     = ((s && multibyte_p)
        || (STRINGP (string) && STRING_MULTIBYTE (string)));
 
-  with_echo_area_buffer (0, -1, set_message_1,
+  with_echo_area_buffer (0, 0, set_message_1,
                          (EMACS_INT) s, string, nbytes, multibyte_p);
   message_buf_print = 0;
   help_echo_showing_p = 0;
@@ -7907,6 +7901,7 @@ set_message_1 (a1, a2, nbytes, multibyte_p)
 
   /* Insert new message at BEG.  */
   TEMP_SET_PT_BOTH (BEG, BEG_BYTE);
+  Ferase_buffer ();
 
   if (STRINGP (string))
     {
@@ -8123,10 +8118,8 @@ echo_area_display (update_frame_p)
   else if (!EQ (mini_window, selected_window))
     windows_or_buffers_changed++;
 
-  /* Last displayed message is now the current message.  */
+  /* The current message is now also the last one displayed.  */
   echo_area_buffer[1] = echo_area_buffer[0];
-  /* Inform read_char that we're not echoing.  */
-  echo_message_buffer = Qnil;
 
   /* Prevent redisplay optimization in redisplay_internal by resetting
      this_line_start_pos.  This is done because the mini-buffer now