X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/8c757fd783f2e89b47255d85aea6aa785e6045a8..32bfb2d565e0ee6d23291895310ea66b146b4de8:/src/undo.c?ds=sidebyside

diff --git a/src/undo.c b/src/undo.c
index 40cebbac6e..9fdc46a3b1 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -36,6 +36,62 @@ Lisp_Object Qinhibit_read_only;
    an undo-boundary.  */
 Lisp_Object pending_boundary;
 
+/* Record point as it was at beginning of this command (if necessary)
+   And prepare the undo info for recording a change.
+   PT is the position of point that will naturally occur as a result of the
+   undo record that will be added just after this command terminates.  */
+
+static void
+record_point (pt)
+     int pt;
+{
+  int at_boundary;
+
+  /* Allocate a cons cell to be the undo boundary after this command.  */
+  if (NILP (pending_boundary))
+    pending_boundary = Fcons (Qnil, Qnil);
+
+  if (!BUFFERP (last_undo_buffer)
+      || current_buffer != XBUFFER (last_undo_buffer))
+    Fundo_boundary ();
+  XSETBUFFER (last_undo_buffer, current_buffer);
+
+  if (CONSP (current_buffer->undo_list))
+    {
+      /* Set AT_BOUNDARY to 1 only when we have nothing other than
+         marker adjustment before undo boundary.  */
+
+      Lisp_Object tail = current_buffer->undo_list, elt;
+
+      while (1)
+	{
+	  if (NILP (tail))
+	    elt = Qnil;
+	  else
+	    elt = XCAR (tail);
+	  if (NILP (elt) || ! (CONSP (elt) && MARKERP (XCAR (elt))))
+	    break;
+	  tail = XCDR (tail);
+	}
+      at_boundary = NILP (elt);
+    }
+  else
+    at_boundary = 1;
+
+  if (MODIFF <= SAVE_MODIFF)
+    record_first_change ();
+
+  /* If we are just after an undo boundary, and
+     point wasn't at start of deleted range, record where it was.  */
+  if (at_boundary
+      && last_point_position != pt
+      /* If we're called from batch mode, this could be nil.  */
+      && BUFFERP (last_point_position_buffer)
+      && current_buffer == XBUFFER (last_point_position_buffer))
+    current_buffer->undo_list
+      = Fcons (make_number (last_point_position), current_buffer->undo_list);
+}
+
 /* Record an insertion that just happened or is about to happen,
    for LENGTH characters at position BEG.
    (It is possible to record an insertion before or after the fact
@@ -50,17 +106,7 @@ record_insert (beg, length)
   if (EQ (current_buffer->undo_list, Qt))
     return;
 
-  /* Allocate a cons cell to be the undo boundary after this command.  */
-  if (NILP (pending_boundary))
-    pending_boundary = Fcons (Qnil, Qnil);
-
-  if (!BUFFERP (last_undo_buffer)
-      || current_buffer != XBUFFER (last_undo_buffer))
-    Fundo_boundary ();
-  XSETBUFFER (last_undo_buffer, current_buffer);
-
-  if (MODIFF <= SAVE_MODIFF)
-    record_first_change ();
+  record_point (beg);
 
   /* If this is following another insertion and consecutive with it
      in the buffer, combine the two.  */
@@ -73,7 +119,7 @@ record_insert (beg, length)
 	  && INTEGERP (XCDR (elt))
 	  && XINT (XCDR (elt)) == beg)
 	{
-	  XSETINT (XCDR (elt), beg + length);
+	  XSETCDR (elt, make_number (beg + length));
 	  return;
 	}
     }
@@ -93,59 +139,20 @@ record_delete (beg, string)
      Lisp_Object string;
 {
   Lisp_Object sbeg;
-  int at_boundary;
 
   if (EQ (current_buffer->undo_list, Qt))
     return;
 
-  /* Allocate a cons cell to be the undo boundary after this command.  */
-  if (NILP (pending_boundary))
-    pending_boundary = Fcons (Qnil, Qnil);
-
-  if (BUFFERP (last_undo_buffer)
-      && current_buffer != XBUFFER (last_undo_buffer))
-    Fundo_boundary ();
-  XSETBUFFER (last_undo_buffer, current_buffer);
-
-  if (CONSP (current_buffer->undo_list))
+  if (PT == beg + SCHARS (string))
     {
-      /* Set AT_BOUNDARY to 1 only when we have nothing other than
-         marker adjustment before undo boundary.  */
-
-      Lisp_Object tail = current_buffer->undo_list, elt;
-
-      while (1)
-	{
-	  if (NILP (tail))
-	    elt = Qnil;
-	  else
-	    elt = XCAR (tail);
-	  if (NILP (elt) || ! (CONSP (elt) && MARKERP (XCAR (elt))))
-	    break;
-	  tail = XCDR (tail);
-	}
-      at_boundary = NILP (elt);
+      XSETINT (sbeg, -beg);
+      record_point (PT);
     }
   else
-    at_boundary = 0;
-
-  if (MODIFF <= SAVE_MODIFF)
-    record_first_change ();
-
-  if (PT == beg + XSTRING (string)->size)
-    XSETINT (sbeg, -beg);
-  else
-    XSETFASTINT (sbeg, beg);
-
-  /* If we are just after an undo boundary, and 
-     point wasn't at start of deleted range, record where it was.  */
-  if (at_boundary
-      && last_point_position != XFASTINT (sbeg)
-      /* If we're called from batch mode, this could be nil.  */
-      && BUFFERP (last_point_position_buffer)
-      && current_buffer == XBUFFER (last_point_position_buffer))
-    current_buffer->undo_list
-      = Fcons (make_number (last_point_position), current_buffer->undo_list);
+    {
+      XSETFASTINT (sbeg, beg);
+      record_point (beg);
+    }
 
   current_buffer->undo_list
     = Fcons (Fcons (string, sbeg), current_buffer->undo_list);
@@ -168,7 +175,7 @@ record_marker_adjustment (marker, adjustment)
   if (NILP (pending_boundary))
     pending_boundary = Fcons (Qnil, Qnil);
 
-  if (!BUFFERP (last_undo_buffer) 
+  if (!BUFFERP (last_undo_buffer)
       || current_buffer != XBUFFER (last_undo_buffer))
     Fundo_boundary ();
   XSETBUFFER (last_undo_buffer, current_buffer);
@@ -257,10 +264,10 @@ record_property_change (beg, length, prop, value, buffer)
 }
 
 DEFUN ("undo-boundary", Fundo_boundary, Sundo_boundary, 0, 0, 0,
-  "Mark a boundary between units of undo.\n\
-An undo command will stop at this point,\n\
-but another undo command will undo to the previous boundary.")
-  ()
+       doc: /* Mark a boundary between units of undo.
+An undo command will stop at this point,
+but another undo command will undo to the previous boundary.  */)
+     ()
 {
   Lisp_Object tem;
   if (EQ (current_buffer->undo_list, Qt))
@@ -273,7 +280,7 @@ but another undo command will undo to the previous boundary.")
 	{
 	  /* If we have preallocated the cons cell to use here,
 	     use that one.  */
-	  XCDR (pending_boundary) = current_buffer->undo_list;
+	  XSETCDR (pending_boundary, current_buffer->undo_list);
 	  current_buffer->undo_list = pending_boundary;
 	  pending_boundary = Qnil;
 	}
@@ -285,14 +292,15 @@ but another undo command will undo to the previous boundary.")
 
 /* At garbage collection time, make an undo list shorter at the end,
    returning the truncated list.
-   MINSIZE and MAXSIZE are the limits on size allowed, as described below.
-   In practice, these are the values of undo-limit and
-   undo-strong-limit.  */
+   MINSIZE, MAXSIZE and LIMITSIZE are the limits on size allowed,
+   as described below.
+   In practice, these are the values of undo-limit,
+   undo-strong-limit, and undo-outer-limit.  */
 
 Lisp_Object
-truncate_undo_list (list, minsize, maxsize)
+truncate_undo_list (list, minsize, maxsize, limitsize)
      Lisp_Object list;
-     int minsize, maxsize;
+     int minsize, maxsize, limitsize;
 {
   Lisp_Object prev, next, last_boundary;
   int size_so_far = 0;
@@ -301,11 +309,12 @@ truncate_undo_list (list, minsize, maxsize)
   next = list;
   last_boundary = Qnil;
 
-  /* Always preserve at least the most recent undo record.
+  /* Always preserve at least the most recent undo record
+     unless it is really horribly big.
      If the first element is an undo boundary, skip past it.
 
      Skip, skip, skip the undo, skip, skip, skip the undo,
-     Skip, skip, skip the undo, skip to the undo bound'ry. 
+     Skip, skip, skip the undo, skip to the undo bound'ry.
      (Get it?  "Skip to my Loo?")  */
   if (CONSP (next) && NILP (XCAR (next)))
     {
@@ -316,6 +325,7 @@ truncate_undo_list (list, minsize, maxsize)
       prev = next;
       next = XCDR (next);
     }
+
   while (CONSP (next) && ! NILP (XCAR (next)))
     {
       Lisp_Object elt;
@@ -328,16 +338,23 @@ truncate_undo_list (list, minsize, maxsize)
 	  size_so_far += sizeof (struct Lisp_Cons);
 	  if (STRINGP (XCAR (elt)))
 	    size_so_far += (sizeof (struct Lisp_String) - 1
-			    + XSTRING (XCAR (elt))->size);
+			    + SCHARS (XCAR (elt)));
 	}
 
+      /* If we reach LIMITSIZE before the first boundary,
+	 we're heading for memory full, so truncate the list to nothing.  */
+      if (size_so_far > limitsize)
+	return Qnil;
+
       /* Advance to next element.  */
       prev = next;
       next = XCDR (next);
     }
+
   if (CONSP (next))
     last_boundary = prev;
 
+  /* Keep more if it fits.  */
   while (CONSP (next))
     {
       Lisp_Object elt;
@@ -363,7 +380,7 @@ truncate_undo_list (list, minsize, maxsize)
 	  size_so_far += sizeof (struct Lisp_Cons);
 	  if (STRINGP (XCAR (elt)))
 	    size_so_far += (sizeof (struct Lisp_String) - 1
-			    + XSTRING (XCAR (elt))->size);
+			    + SCHARS (XCAR (elt)));
 	}
 
       /* Advance to next element.  */
@@ -378,7 +395,7 @@ truncate_undo_list (list, minsize, maxsize)
   /* Truncate at the boundary where we decided to truncate.  */
   if (!NILP (last_boundary))
     {
-      XCDR (last_boundary) = Qnil;
+      XSETCDR (last_boundary, Qnil);
       return list;
     }
   else
@@ -386,16 +403,16 @@ truncate_undo_list (list, minsize, maxsize)
 }
 
 DEFUN ("primitive-undo", Fprimitive_undo, Sprimitive_undo, 2, 2, 0,
-  "Undo N records from the front of the list LIST.\n\
-Return what remains of the list.")
-  (n, list)
+       doc: /* Undo N records from the front of the list LIST.
+Return what remains of the list.  */)
+     (n, list)
      Lisp_Object n, list;
 {
   struct gcpro gcpro1, gcpro2;
   Lisp_Object next;
-  int count = BINDING_STACK_SIZE ();
+  int count = SPECPDL_INDEX ();
   register int arg;
-  
+
 #if 0  /* This is a good feature, but would make undo-start
 	  unable to do what is expected.  */
   Lisp_Object tem;
@@ -407,13 +424,14 @@ Return what remains of the list.")
     list = Fcdr (list);
 #endif
 
-  CHECK_NUMBER (n, 0);
+  CHECK_NUMBER (n);
   arg = XINT (n);
   next = Qnil;
   GCPRO2 (next, list);
 
-  /* Don't let read-only properties interfere with undo.  */
-  if (!NILP (current_buffer->read_only))
+  /* In a writable buffer, enable undoing read-only text that is so
+     because of text properties.  */
+  if (NILP (current_buffer->read_only))
     specbind (Qinhibit_read_only, Qt);
 
   /* Don't let `intangible' properties interfere with undo.  */
@@ -421,10 +439,10 @@ Return what remains of the list.")
 
   while (arg > 0)
     {
-      while (1)
+      while (CONSP (list))
 	{
-	  next = Fcar (list);
-	  list = Fcdr (list);
+	  next = XCAR (list);
+	  list = XCDR (list);
 	  /* Exit inner loop at undo boundary.  */
 	  if (NILP (next))
 	    break;
@@ -435,8 +453,8 @@ Return what remains of the list.")
 	    {
 	      Lisp_Object car, cdr;
 
-	      car = Fcar (next);
-	      cdr = Fcdr (next);
+	      car = XCAR (next);
+	      cdr = XCDR (next);
 	      if (EQ (car, Qt))
 		{
 		  /* Element (t high . low) records previous modtime.  */
@@ -478,7 +496,6 @@ Return what remains of the list.")
 	      else if (INTEGERP (car) && INTEGERP (cdr))
 		{
 		  /* Element (BEG . END) means range was inserted.  */
-		  Lisp_Object end;
 
 		  if (XINT (car) < BEGV
 		      || XINT (cdr) > ZV)
@@ -547,3 +564,6 @@ syms_of_undo ()
   defsubr (&Sprimitive_undo);
   defsubr (&Sundo_boundary);
 }
+
+/* arch-tag: d546ee01-4aed-4ffb-bb8b-eefaae50d38a
+   (do not change this comment) */