X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/81c1cf71feec0cd6f906141d741dccfb76aae3de..03da5d089a8ed035cec443a27259e7d21487a22e:/src/undo.c

diff --git a/src/undo.c b/src/undo.c
index df4b8d08cd..9839906ca7 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -1,5 +1,6 @@
 /* undo handling for GNU Emacs.
-   Copyright (C) 1990, 1993, 1994, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1990, 1993, 1994, 2000, 2002, 2003, 2004,
+                 2005 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -15,8 +16,8 @@ GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with GNU Emacs; see the file COPYING.  If not, write to
-the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA.  */
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
 
 
 #include <config.h>
@@ -40,6 +41,10 @@ Lisp_Object last_undo_buffer;
 
 Lisp_Object Qinhibit_read_only;
 
+/* Marker for function call undo list elements.  */
+
+Lisp_Object Qapply;
+
 /* The first time a command records something for undo.
    it also allocates the undo-boundary object
    which will be added to the list at the end of the command.
@@ -450,6 +455,8 @@ Return what remains of the list.  */)
   Lisp_Object next;
   int count = SPECPDL_INDEX ();
   register int arg;
+  Lisp_Object oldlist;
+  int did_apply = 0;
 
 #if 0  /* This is a good feature, but would make undo-start
 	  unable to do what is expected.  */
@@ -466,6 +473,8 @@ Return what remains of the list.  */)
   arg = XINT (n);
   next = Qnil;
   GCPRO2 (next, list);
+  /* I don't think we need to gcpro oldlist, as we use it only
+     to check for EQ.  ++kfs  */
 
   /* In a writable buffer, enable undoing read-only text that is so
      because of text properties.  */
@@ -475,6 +484,8 @@ Return what remains of the list.  */)
   /* Don't let `intangible' properties interfere with undo.  */
   specbind (Qinhibit_point_motion_hooks, Qt);
 
+  oldlist = current_buffer->undo_list;
+
   while (arg > 0)
     {
       while (CONSP (list))
@@ -519,7 +530,7 @@ Return what remains of the list.  */)
 		}
 	      else if (EQ (car, Qnil))
 		{
-		  /* Element (nil prop val beg . end) is property change.  */
+		  /* Element (nil PROP VAL BEG . END) is property change.  */
 		  Lisp_Object beg, end, prop, val;
 
 		  prop = Fcar (cdr);
@@ -543,6 +554,41 @@ Return what remains of the list.  */)
 		  Fgoto_char (car);
 		  Fdelete_region (car, cdr);
 		}
+	      else if (EQ (car, Qapply))
+		{
+		  /* Element (apply FUN . ARGS) means call FUN to undo.  */
+		  struct buffer *save_buffer = current_buffer;
+
+		  car = Fcar (cdr);
+		  cdr = Fcdr (cdr);
+		  if (INTEGERP (car))
+		    {
+		      /* Long format: (apply DELTA START END FUN . ARGS).  */
+		      Lisp_Object delta = car;
+		      Lisp_Object start = Fcar (cdr);
+		      Lisp_Object end   = Fcar (Fcdr (cdr));
+		      Lisp_Object start_mark = Fcopy_marker (start, Qnil);
+		      Lisp_Object end_mark   = Fcopy_marker (end, Qt);
+
+		      cdr = Fcdr (Fcdr (cdr));
+		      apply1 (Fcar (cdr), Fcdr (cdr));
+
+		      /* Check that the function did what the entry said it
+			 would do.  */
+		      if (!EQ (start, Fmarker_position (start_mark))
+			  || (XINT (delta) + XINT (end)
+			      != marker_position (end_mark)))
+			error ("Changes to be undone by function different than announced");
+		      Fset_marker (start_mark, Qnil, Qnil);
+		      Fset_marker (end_mark, Qnil, Qnil);
+		    }
+		  else
+		    apply1 (car, cdr);
+
+		  if (save_buffer != current_buffer)
+		    error ("Undo function switched buffer");
+		  did_apply = 1;
+		}
 	      else if (STRINGP (car) && INTEGERP (cdr))
 		{
 		  /* Element (STRING . POS) means STRING was deleted.  */
@@ -586,16 +632,28 @@ Return what remains of the list.  */)
       arg--;
     }
 
+
+  /* Make sure an apply entry produces at least one undo entry,
+     so the test in `undo' for continuing an undo series
+     will work right.  */
+  if (did_apply
+      && EQ (oldlist, current_buffer->undo_list))
+    current_buffer->undo_list
+      = Fcons (list3 (Qapply, Qcdr, Qnil), current_buffer->undo_list);
+
   UNGCPRO;
   return unbind_to (count, list);
 }
-
+
 void
 syms_of_undo ()
 {
   Qinhibit_read_only = intern ("inhibit-read-only");
   staticpro (&Qinhibit_read_only);
 
+  Qapply = intern ("apply");
+  staticpro (&Qapply);
+
   pending_boundary = Qnil;
   staticpro (&pending_boundary);
 
@@ -627,17 +685,19 @@ which includes both saved text and other data.  */);
   DEFVAR_LISP ("undo-outer-limit", &Vundo_outer_limit,
 	      doc: /* Outer limit on size of undo information for one command.
 At garbage collection time, if the current command has produced
-more than this much undo information, it asks you whether to delete
-the information.  This is a last-ditch limit to prevent memory overflow.
+more than this much undo information, it discards the info and displays
+a warning.  This is a last-ditch limit to prevent memory overflow.
 
-The size is counted as the number of bytes occupied,
-which includes both saved text and other data.
+The size is counted as the number of bytes occupied, which includes
+both saved text and other data.  A value of nil means no limit.  In
+this case, accumulating one huge undo entry could make Emacs crash as
+a result of memory overflow.
 
 In fact, this calls the function which is the value of
 `undo-outer-limit-function' with one argument, the size.
 The text above describes the behavior of the function
 that variable usually specifies.  */);
-  Vundo_outer_limit = make_number (300000);
+  Vundo_outer_limit = make_number (3000000);
 
   DEFVAR_LISP ("undo-outer-limit-function", &Vundo_outer_limit_function,
 	       doc: /* Function to call when an undo list exceeds `undo-outer-limit'.