/* undo handling for GNU Emacs.
- Copyright (C) 1990, 1993, 1994 Free Software Foundation, Inc.
+ Copyright (C) 1990, 1993, 1994, 2000, 2001, 2002, 2003, 2004,
+ 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
This file is part of GNU Emacs.
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
GNU Emacs is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY. No author or distributor
-accepts responsibility to anyone for the consequences of using it
-or for whether it serves any particular purpose or works at all,
-unless he says so in writing. Refer to the GNU Emacs General Public
-License for full details.
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
-Everyone is granted permission to copy, modify and redistribute
-GNU Emacs, but only under the conditions described in the
-GNU Emacs General Public License. A copy of this license is
-supposed to have been given to you along with GNU Emacs so you
-can know your rights and responsibilities. It should be in a
-file named COPYING. Among other things, the copyright notice
-and this notice must be preserved on all copies. */
+You should have received a copy of the GNU General Public License
+along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
+#include <setjmp.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;
+/* BEWARE: This is not traced by the GC, so never dereference it! */
+struct buffer *last_undo_buffer;
+
+/* Position of point last time we inserted a boundary. */
+struct buffer *last_boundary_buffer;
+EMACS_INT last_boundary_position;
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.
an undo-boundary. */
Lisp_Object pending_boundary;
-/* 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
- because we don't need to record the contents.) */
+/* Nonzero means do not record point in record_point. */
+
+int undo_inhibit_record_point;
-record_insert (beg, length)
- Lisp_Object beg, length;
+/* 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 (int pt)
{
- Lisp_Object lbeg, lend;
+ int at_boundary;
- if (EQ (current_buffer->undo_list, Qt))
+ /* Don't record position of pt when undo_inhibit_record_point holds. */
+ if (undo_inhibit_record_point)
return;
/* Allocate a cons cell to be the undo boundary after this command. */
if (NILP (pending_boundary))
pending_boundary = Fcons (Qnil, Qnil);
- if (current_buffer != XBUFFER (last_undo_buffer))
+ if ((current_buffer != last_undo_buffer)
+ /* Don't call Fundo_boundary for the first change. Otherwise we
+ risk overwriting last_boundary_position in Fundo_boundary with
+ PT of the current buffer and as a consequence not insert an
+ undo boundary because last_boundary_position will equal pt in
+ the test at the end of the present function (Bug#731). */
+ && (MODIFF > SAVE_MODIFF))
Fundo_boundary ();
- XSETBUFFER (last_undo_buffer, current_buffer);
+ 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;
- if (MODIFF <= current_buffer->save_modified)
+ 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
+ && current_buffer == last_boundary_buffer
+ && last_boundary_position != pt)
+ current_buffer->undo_list
+ = Fcons (make_number (last_boundary_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
+ because we don't need to record the contents.) */
+
+void
+record_insert (int beg, int length)
+{
+ Lisp_Object lbeg, lend;
+
+ if (EQ (current_buffer->undo_list, Qt))
+ return;
+
+ record_point (beg);
+
/* If this is following another insertion and consecutive with it
in the buffer, combine the two. */
if (CONSP (current_buffer->undo_list))
{
Lisp_Object elt;
- elt = XCONS (current_buffer->undo_list)->car;
+ elt = XCAR (current_buffer->undo_list);
if (CONSP (elt)
- && INTEGERP (XCONS (elt)->car)
- && INTEGERP (XCONS (elt)->cdr)
- && XINT (XCONS (elt)->cdr) == XINT (beg))
+ && INTEGERP (XCAR (elt))
+ && INTEGERP (XCDR (elt))
+ && XINT (XCDR (elt)) == beg)
{
- XSETINT (XCONS (elt)->cdr, XINT (beg) + XINT (length));
+ XSETCDR (elt, make_number (beg + length));
return;
}
}
- lbeg = beg;
- XSETINT (lend, XINT (beg) + XINT (length));
+ XSETFASTINT (lbeg, beg);
+ XSETINT (lend, beg + length);
current_buffer->undo_list = Fcons (Fcons (lbeg, lend),
current_buffer->undo_list);
}
/* Record that a deletion is about to take place,
- for LENGTH characters at location BEG. */
+ of the characters in STRING, at location BEG. */
-record_delete (beg, length)
- int beg, length;
+void
+record_delete (int beg, Lisp_Object string)
{
- Lisp_Object lbeg, lend, sbeg;
- int at_boundary;
+ Lisp_Object sbeg;
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 (PT == beg + SCHARS (string))
+ {
+ XSETINT (sbeg, -beg);
+ record_point (PT);
+ }
+ else
+ {
+ XSETFASTINT (sbeg, beg);
+ record_point (beg);
+ }
- if (current_buffer != XBUFFER (last_undo_buffer))
- Fundo_boundary ();
- XSETBUFFER (last_undo_buffer, current_buffer);
+ current_buffer->undo_list
+ = Fcons (Fcons (string, sbeg), current_buffer->undo_list);
+}
- at_boundary = (CONSP (current_buffer->undo_list)
- && NILP (XCONS (current_buffer->undo_list)->car));
+/* Record the fact that MARKER is about to be adjusted by ADJUSTMENT.
+ This is done only when a marker points within text being deleted,
+ because that's the only case where an automatic marker adjustment
+ won't be inverted automatically by undoing the buffer modification. */
- if (MODIFF <= current_buffer->save_modified)
- record_first_change ();
+void
+record_marker_adjustment (Lisp_Object marker, int adjustment)
+{
+ if (EQ (current_buffer->undo_list, Qt))
+ return;
- if (point == beg + length)
- XSETINT (sbeg, -beg);
- else
- XSETFASTINT (sbeg, beg);
- XSETFASTINT (lbeg, beg);
- XSETFASTINT (lend, beg + length);
+ /* Allocate a cons cell to be the undo boundary after this command. */
+ if (NILP (pending_boundary))
+ pending_boundary = Fcons (Qnil, Qnil);
- /* 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)
- && current_buffer == XBUFFER (last_point_position_buffer))
- current_buffer->undo_list
- = Fcons (make_number (last_point_position), current_buffer->undo_list);
+ if (current_buffer != last_undo_buffer)
+ Fundo_boundary ();
+ last_undo_buffer = current_buffer;
current_buffer->undo_list
- = Fcons (Fcons (Fbuffer_substring (lbeg, lend), sbeg),
+ = Fcons (Fcons (marker, make_number (adjustment)),
current_buffer->undo_list);
}
/* Record that a replacement is about to take place,
for LENGTH characters at location BEG.
- The replacement does not change the number of characters. */
+ The replacement must not change the number of characters. */
-record_change (beg, length)
- int beg, length;
+void
+record_change (int beg, int length)
{
- record_delete (beg, length);
+ record_delete (beg, make_buffer_string (beg, beg + length, 1));
record_insert (beg, length);
}
\f
Record the file modification date so that when undoing this entry
we can tell whether it is obsolete because the file was saved again. */
-record_first_change ()
+void
+record_first_change (void)
{
Lisp_Object high, low;
+ struct buffer *base_buffer = current_buffer;
if (EQ (current_buffer->undo_list, Qt))
return;
- if (current_buffer != XBUFFER (last_undo_buffer))
+ if (current_buffer != last_undo_buffer)
Fundo_boundary ();
- XSETBUFFER (last_undo_buffer, current_buffer);
+ last_undo_buffer = current_buffer;
+
+ if (base_buffer->base_buffer)
+ base_buffer = base_buffer->base_buffer;
- XSETFASTINT (high, (current_buffer->modtime >> 16) & 0xffff);
- XSETFASTINT (low, current_buffer->modtime & 0xffff);
+ XSETFASTINT (high, (base_buffer->modtime >> 16) & 0xffff);
+ XSETFASTINT (low, base_buffer->modtime & 0xffff);
current_buffer->undo_list = Fcons (Fcons (Qt, Fcons (high, low)), current_buffer->undo_list);
}
/* Record a change in property PROP (whose old value was VAL)
for LENGTH characters starting at position BEG in BUFFER. */
-record_property_change (beg, length, prop, value, buffer)
- int beg, length;
- Lisp_Object prop, value, buffer;
+void
+record_property_change (int beg, int length, Lisp_Object prop, Lisp_Object value, Lisp_Object buffer)
{
Lisp_Object lbeg, lend, entry;
- struct buffer *obuf = current_buffer;
+ struct buffer *obuf = current_buffer, *buf = XBUFFER (buffer);
int boundary = 0;
- if (EQ (XBUFFER (buffer)->undo_list, Qt))
+ if (EQ (buf->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 (!EQ (buffer, last_undo_buffer))
+ if (buf != last_undo_buffer)
boundary = 1;
- last_undo_buffer = buffer;
+ last_undo_buffer = buf;
/* Switch temporarily to the buffer that was changed. */
- current_buffer = XBUFFER (buffer);
+ current_buffer = buf;
if (boundary)
Fundo_boundary ();
- if (MODIFF <= current_buffer->save_modified)
+ if (MODIFF <= SAVE_MODIFF)
record_first_change ();
XSETINT (lbeg, beg);
}
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))
{
/* If we have preallocated the cons cell to use here,
use that one. */
- XCONS (pending_boundary)->cdr = current_buffer->undo_list;
+ XSETCDR (pending_boundary, current_buffer->undo_list);
current_buffer->undo_list = pending_boundary;
pending_boundary = Qnil;
}
else
current_buffer->undo_list = Fcons (Qnil, current_buffer->undo_list);
}
+ last_boundary_position = PT;
+ last_boundary_buffer = current_buffer;
return Qnil;
}
/* 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. */
-
-Lisp_Object
-truncate_undo_list (list, minsize, maxsize)
- Lisp_Object list;
- int minsize, maxsize;
+ 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 (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.
- 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 (CONSP (next) && NILP (XCONS (next)->car))
+ /* 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. */
size_so_far += sizeof (struct Lisp_Cons);
/* Advance to next element. */
prev = next;
- next = XCONS (next)->cdr;
+ next = XCDR (next);
}
- while (CONSP (next) && ! NILP (XCONS (next)->car))
+
+ /* 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;
- elt = XCONS (next)->car;
+ elt = XCAR (next);
/* Add in the space occupied by this element and its chain link. */
size_so_far += sizeof (struct Lisp_Cons);
if (CONSP (elt))
{
size_so_far += sizeof (struct Lisp_Cons);
- if (STRINGP (XCONS (elt)->car))
+ if (STRINGP (XCAR (elt)))
size_so_far += (sizeof (struct Lisp_String) - 1
- + XSTRING (XCONS (elt)->car)->size);
+ + SCHARS (XCAR (elt)));
}
/* Advance to next element. */
prev = next;
- next = XCONS (next)->cdr;
+ 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 tem;
+ struct buffer *temp = last_undo_buffer;
+
+ /* 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 additional undo data, if it fits in the limits. */
while (CONSP (next))
{
Lisp_Object elt;
- elt = XCONS (next)->car;
+ 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 (CONSP (elt))
{
size_so_far += sizeof (struct Lisp_Cons);
- if (STRINGP (XCONS (elt)->car))
+ if (STRINGP (XCAR (elt)))
size_so_far += (sizeof (struct Lisp_String) - 1
- + XSTRING (XCONS (elt)->car)->size);
+ + SCHARS (XCAR (elt)));
}
/* Advance to next element. */
prev = next;
- next = XCONS (next)->cdr;
+ next = XCDR (next);
}
/* 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))
- {
- XCONS (last_boundary)->cdr = 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,
- "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 = specpdl_ptr - specpdl;
+ 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. */
Lisp_Object tem;
list = Fcdr (list);
#endif
- CHECK_NUMBER (n, 0);
+ CHECK_NUMBER (n);
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 */
- /* Don't let read-only properties interfere with undo. */
+ /* 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. */
+ specbind (Qinhibit_point_motion_hooks, Qt);
+
+ oldlist = current_buffer->undo_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;
{
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. */
Lisp_Object high, low;
int mod_time;
+ struct buffer *base_buffer = current_buffer;
high = Fcar (cdr);
low = Fcdr (cdr);
mod_time = (XFASTINT (high) << 16) + XFASTINT (low);
+
+ if (current_buffer->base_buffer)
+ base_buffer = current_buffer->base_buffer;
+
/* If this records an obsolete save
(not matching the actual disk file)
then don't mark unmodified. */
- if (mod_time != current_buffer->modtime)
- break;
+ if (mod_time != base_buffer->modtime)
+ continue;
#ifdef CLASH_DETECTION
Funlock_buffer ();
#endif /* CLASH_DETECTION */
Fset_buffer_modified_p (Qnil);
}
-#ifdef USE_TEXT_PROPERTIES
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);
beg = Fcar (cdr);
end = Fcdr (cdr);
+ if (XINT (beg) < BEGV || XINT (end) > ZV)
+ error ("Changes to be undone are outside visible portion of buffer");
Fput_text_property (beg, end, prop, val, Qnil);
}
-#endif /* USE_TEXT_PROPERTIES */
else if (INTEGERP (car) && INTEGERP (cdr))
{
/* Element (BEG . END) means range was inserted. */
- Lisp_Object end;
if (XINT (car) < BEGV
|| XINT (cdr) > ZV)
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. */
error ("Changes to be undone are outside visible portion of buffer");
SET_PT (pos);
- /* Insert before markers so that if the mark is
- currently on the boundary of this deletion, it
- ends up on the other side of the now-undeleted
- text from point. Since undo doesn't even keep
- track of the mark, this isn't really necessary,
- but it may lead to better behavior in certain
- situations. */
- Finsert_before_markers (1, &membuf);
+ /* Now that we record marker adjustments
+ (caused by deletion) for undo,
+ we should always insert after markers,
+ so that undoing the marker adjustments
+ put the markers back in the right place. */
+ Finsert (1, &membuf);
SET_PT (pos);
}
}
+ else if (MARKERP (car) && INTEGERP (cdr))
+ {
+ /* (MARKER . INTEGER) means a marker MARKER
+ was adjusted by INTEGER. */
+ if (XMARKER (car)->buffer)
+ Fset_marker (car,
+ make_number (marker_position (car) - XINT (cdr)),
+ Fmarker_buffer (car));
+ }
}
}
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);
}
-
-syms_of_undo ()
+\f
+void
+syms_of_undo (void)
{
- Qinhibit_read_only = intern ("inhibit-read-only");
+ Qinhibit_read_only = intern_c_string ("inhibit-read-only");
staticpro (&Qinhibit_read_only);
+ Qapply = intern_c_string ("apply");
+ staticpro (&Qapply);
+
pending_boundary = Qnil;
staticpro (&pending_boundary);
+ last_undo_buffer = NULL;
+ last_boundary_buffer = NULL;
+
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 = 80000;
+
+ 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 = 120000;
+
+ 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 (12000000);
+
+ 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;
+
+ DEFVAR_BOOL ("undo-inhibit-record-point", &undo_inhibit_record_point,
+ doc: /* Non-nil means do not record `point' in `buffer-undo-list'. */);
+ undo_inhibit_record_point = 0;
}
+
+/* arch-tag: d546ee01-4aed-4ffb-bb8b-eefaae50d38a
+ (do not change this comment) */