/* 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, 2006 Free Software Foundation, Inc.
This file is part of GNU Emacs.
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>
#include "lisp.h"
#include "buffer.h"
#include "commands.h"
+#include "window.h"
+
+/* Limits controlling how much undo information to keep. */
+
+EMACS_INT undo_limit;
+EMACS_INT undo_strong_limit;
+
+Lisp_Object Vundo_outer_limit;
+
+/* Function to call when undo_outer_limit is exceeded. */
+
+Lisp_Object Vundo_outer_limit_function;
/* Last buffer for which undo information was recorded. */
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.
/* 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)
+ /* If we're called from batch mode, this could be nil. */
&& current_buffer == XBUFFER (last_point_position_buffer))
- current_buffer->undo_list
- = Fcons (make_number (last_point_position), current_buffer->undo_list);
+ {
+ /* If we have switched windows, use the point value
+ from the window we are in. */
+ if (! EQ (last_point_position_window, selected_window))
+ last_point_position = marker_position (XWINDOW (selected_window)->pointm);
+
+ if (last_point_position != pt)
+ 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,
}
/* At garbage collection time, make an undo list shorter at the end,
- returning the truncated list.
- 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, limitsize)
- Lisp_Object list;
- int minsize, maxsize, limitsize;
+ returning the truncated list. How this is done depends on the
+ variables undo-limit, undo-strong-limit and undo-outer-limit.
+ In some cases this works by calling undo-outer-limit-function. */
+
+void
+truncate_undo_list (b)
+ struct buffer *b;
{
+ Lisp_Object list;
Lisp_Object prev, next, last_boundary;
int size_so_far = 0;
+ /* Make sure that calling undo-outer-limit-function
+ won't cause another GC. */
+ int count = inhibit_garbage_collection ();
+
+ /* Make the buffer current to get its local values of variables such
+ as undo_limit. Also so that Vundo_outer_limit_function can
+ tell which buffer to operate on. */
+ record_unwind_protect (set_buffer_if_live, Fcurrent_buffer ());
+ set_buffer_internal (b);
+
+ list = b->undo_list;
+
prev = Qnil;
next = list;
last_boundary = Qnil;
- /* 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.
- (Get it? "Skip to my Loo?") */
+ /* If the first element is an undo boundary, skip past it. */
if (CONSP (next) && NILP (XCAR (next)))
{
/* Add in the space occupied by this element and its chain link. */
next = XCDR (next);
}
+ /* Always preserve at least the most recent undo record
+ unless it is really horribly big.
+
+ Skip, skip, skip the undo, skip, skip, skip the undo,
+ Skip, skip, skip the undo, skip to the undo bound'ry. */
+
while (CONSP (next) && ! NILP (XCAR (next)))
{
Lisp_Object elt;
+ 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 by the first boundary we have already passed undo_outer_limit,
+ we're heading for memory full, so offer to clear out the list. */
+ if (INTEGERP (Vundo_outer_limit)
+ && size_so_far > XINT (Vundo_outer_limit)
+ && !NILP (Vundo_outer_limit_function))
+ {
+ Lisp_Object temp = last_undo_buffer, tem;
+
+ /* Normally the function this calls is undo-outer-limit-truncate. */
+ tem = call1 (Vundo_outer_limit_function, make_number (size_so_far));
+ if (! NILP (tem))
+ {
+ /* The function is responsible for making
+ any desired changes in buffer-undo-list. */
+ unbind_to (count, Qnil);
+ return;
+ }
+ /* That function probably used the minibuffer, and if so, that
+ changed last_undo_buffer. Change it back so that we don't
+ force next change to make an undo boundary here. */
+ last_undo_buffer = temp;
+ }
+
if (CONSP (next))
last_boundary = prev;
- /* Keep more if it fits. */
+ /* Keep additional undo data, if it fits in the limits. */
while (CONSP (next))
{
Lisp_Object elt;
elt = XCAR (next);
/* When we get to a boundary, decide whether to truncate
- either before or after it. The lower threshold, MINSIZE,
+ either before or after it. The lower threshold, undo_limit,
tells us to truncate after it. If its size pushes past
- the higher threshold MAXSIZE as well, we truncate before it. */
+ the higher threshold undo_strong_limit, we truncate before it. */
if (NILP (elt))
{
- if (size_so_far > maxsize)
+ if (size_so_far > undo_strong_limit)
break;
last_boundary = prev;
- if (size_so_far > minsize)
+ if (size_so_far > undo_limit)
break;
}
/* If we scanned the whole list, it is short enough; don't change it. */
if (NILP (next))
- return list;
-
+ ;
/* Truncate at the boundary where we decided to truncate. */
- if (!NILP (last_boundary))
- {
- XSETCDR (last_boundary, Qnil);
- return list;
- }
+ else if (!NILP (last_boundary))
+ XSETCDR (last_boundary, Qnil);
+ /* There's nothing we decided to keep, so clear it out. */
else
- return Qnil;
+ b->undo_list = Qnil;
+
+ unbind_to (count, Qnil);
}
\f
DEFUN ("primitive-undo", Fprimitive_undo, Sprimitive_undo, 2, 2, 0,
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. */
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. */
/* 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))
}
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);
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. */
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);
}
-
+\f
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);
defsubr (&Sprimitive_undo);
defsubr (&Sundo_boundary);
+
+ DEFVAR_INT ("undo-limit", &undo_limit,
+ doc: /* Keep no more undo information once it exceeds this size.
+This limit is applied when garbage collection happens.
+When a previous command increases the total undo list size past this
+value, the earlier commands that came before it are forgotten.
+
+The size is counted as the number of bytes occupied,
+which includes both saved text and other data. */);
+ undo_limit = 20000;
+
+ DEFVAR_INT ("undo-strong-limit", &undo_strong_limit,
+ doc: /* Don't keep more than this much size of undo information.
+This limit is applied when garbage collection happens.
+When a previous command increases the total undo list size past this
+value, that command and the earlier commands that came before it are forgotten.
+However, the most recent buffer-modifying command's undo info
+is never discarded for this reason.
+
+The size is counted as the number of bytes occupied,
+which includes both saved text and other data. */);
+ undo_strong_limit = 30000;
+
+ 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 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. 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 (3000000);
+
+ DEFVAR_LISP ("undo-outer-limit-function", &Vundo_outer_limit_function,
+ doc: /* Function to call when an undo list exceeds `undo-outer-limit'.
+This function is called with one argument, the current undo list size
+for the most recent command (since the last undo boundary).
+If the function returns t, that means truncation has been fully handled.
+If it returns nil, the other forms of truncation are done.
+
+Garbage collection is inhibited around the call to this function,
+so it must make sure not to do a lot of consing. */);
+ Vundo_outer_limit_function = Qnil;
}
/* arch-tag: d546ee01-4aed-4ffb-bb8b-eefaae50d38a