Mercurial > hg > xemacs-beta
view src/undo.c @ 665:fdefd0186b75
[xemacs-hg @ 2001-09-20 06:28:42 by ben]
The great integral types renaming.
The purpose of this is to rationalize the names used for various
integral types, so that they match their intended uses and follow
consist conventions, and eliminate types that were not semantically
different from each other.
The conventions are:
-- All integral types that measure quantities of anything are
signed. Some people disagree vociferously with this, but their
arguments are mostly theoretical, and are vastly outweighed by
the practical headaches of mixing signed and unsigned values,
and more importantly by the far increased likelihood of
inadvertent bugs: Because of the broken "viral" nature of
unsigned quantities in C (operations involving mixed
signed/unsigned are done unsigned, when exactly the opposite is
nearly always wanted), even a single error in declaring a
quantity unsigned that should be signed, or even the even more
subtle error of comparing signed and unsigned values and
forgetting the necessary cast, can be catastrophic, as
comparisons will yield wrong results. -Wsign-compare is turned
on specifically to catch this, but this tends to result in a
great number of warnings when mixing signed and unsigned, and
the casts are annoying. More has been written on this
elsewhere.
-- All such quantity types just mentioned boil down to EMACS_INT,
which is 32 bits on 32-bit machines and 64 bits on 64-bit
machines. This is guaranteed to be the same size as Lisp
objects of type `int', and (as far as I can tell) of size_t
(unsigned!) and ssize_t. The only type below that is not an
EMACS_INT is Hashcode, which is an unsigned value of the same
size as EMACS_INT.
-- Type names should be relatively short (no more than 10
characters or so), with the first letter capitalized and no
underscores if they can at all be avoided.
-- "count" == a zero-based measurement of some quantity. Includes
sizes, offsets, and indexes.
-- "bpos" == a one-based measurement of a position in a buffer.
"Charbpos" and "Bytebpos" count text in the buffer, rather than
bytes in memory; thus Bytebpos does not directly correspond to
the memory representation. Use "Membpos" for this.
-- "Char" refers to internal-format characters, not to the C type
"char", which is really a byte.
-- For the actual name changes, see the script below.
I ran the following script to do the conversion. (NOTE: This script
is idempotent. You can safely run it multiple times and it will
not screw up previous results -- in fact, it will do nothing if
nothing has changed. Thus, it can be run repeatedly as necessary
to handle patches coming in from old workspaces, or old branches.)
There are two tags, just before and just after the change:
`pre-integral-type-rename' and `post-integral-type-rename'. When
merging code from the main trunk into a branch, the best thing to
do is first merge up to `pre-integral-type-rename', then apply the
script and associated changes, then merge from
`post-integral-type-change' to the present. (Alternatively, just do
the merging in one operation; but you may then have a lot of
conflicts needing to be resolved by hand.)
Script `fixtypes.sh' follows:
----------------------------------- cut ------------------------------------
files="*.[ch] s/*.h m/*.h config.h.in ../configure.in Makefile.in.in ../lib-src/*.[ch] ../lwlib/*.[ch]"
gr Memory_Count Bytecount $files
gr Lstream_Data_Count Bytecount $files
gr Element_Count Elemcount $files
gr Hash_Code Hashcode $files
gr extcount bytecount $files
gr bufpos charbpos $files
gr bytind bytebpos $files
gr memind membpos $files
gr bufbyte intbyte $files
gr Extcount Bytecount $files
gr Bufpos Charbpos $files
gr Bytind Bytebpos $files
gr Memind Membpos $files
gr Bufbyte Intbyte $files
gr EXTCOUNT BYTECOUNT $files
gr BUFPOS CHARBPOS $files
gr BYTIND BYTEBPOS $files
gr MEMIND MEMBPOS $files
gr BUFBYTE INTBYTE $files
gr MEMORY_COUNT BYTECOUNT $files
gr LSTREAM_DATA_COUNT BYTECOUNT $files
gr ELEMENT_COUNT ELEMCOUNT $files
gr HASH_CODE HASHCODE $files
----------------------------------- cut ------------------------------------
`fixtypes.sh' is a Bourne-shell script; it uses 'gr':
----------------------------------- cut ------------------------------------
#!/bin/sh
# Usage is like this:
# gr FROM TO FILES ...
# globally replace FROM with TO in FILES. FROM and TO are regular expressions.
# backup files are stored in the `backup' directory.
from="$1"
to="$2"
shift 2
echo ${1+"$@"} | xargs global-replace "s/$from/$to/g"
----------------------------------- cut ------------------------------------
`gr' in turn uses a Perl script to do its real work,
`global-replace', which follows:
----------------------------------- cut ------------------------------------
: #-*- Perl -*-
### global-modify --- modify the contents of a file by a Perl expression
## Copyright (C) 1999 Martin Buchholz.
## Copyright (C) 2001 Ben Wing.
## Authors: Martin Buchholz <martin@xemacs.org>, Ben Wing <ben@xemacs.org>
## Maintainer: Ben Wing <ben@xemacs.org>
## Current Version: 1.0, May 5, 2001
# This program 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 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, 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.
#
# You should have received a copy of the GNU General Public License
# along with XEmacs; see the file COPYING. If not, write to the Free
# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
eval 'exec perl -w -S $0 ${1+"$@"}'
if 0;
use strict;
use FileHandle;
use Carp;
use Getopt::Long;
use File::Basename;
(my $myName = $0) =~ s@.*/@@; my $usage="
Usage: $myName [--help] [--backup-dir=DIR] [--line-mode] [--hunk-mode]
PERLEXPR FILE ...
Globally modify a file, either line by line or in one big hunk.
Typical usage is like this:
[with GNU print, GNU xargs: guaranteed to handle spaces, quotes, etc.
in file names]
find . -name '*.[ch]' -print0 | xargs -0 $0 's/\bCONST\b/const/g'\n
[with non-GNU print, xargs]
find . -name '*.[ch]' -print | xargs $0 's/\bCONST\b/const/g'\n
The file is read in, either line by line (with --line-mode specified)
or in one big hunk (with --hunk-mode specified; it's the default), and
the Perl expression is then evalled with \$_ set to the line or hunk of
text, including the terminating newline if there is one. It should
destructively modify the value there, storing the changed result in \$_.
Files in which any modifications are made are backed up to the directory
specified using --backup-dir, or to `backup' by default. To disable this,
use --backup-dir= with no argument.
Hunk mode is the default because it is MUCH MUCH faster than line-by-line.
Use line-by-line only when it matters, e.g. you want to do a replacement
only once per line (the default without the `g' argument). Conversely,
when using hunk mode, *ALWAYS* use `g'; otherwise, you will only make one
replacement in the entire file!
";
my %options = ();
$Getopt::Long::ignorecase = 0;
&GetOptions (
\%options,
'help', 'backup-dir=s', 'line-mode', 'hunk-mode',
);
die $usage if $options{"help"} or @ARGV <= 1;
my $code = shift;
die $usage if grep (-d || ! -w, @ARGV);
sub SafeOpen {
open ((my $fh = new FileHandle), $_[0]);
confess "Can't open $_[0]: $!" if ! defined $fh;
return $fh;
}
sub SafeClose {
close $_[0] or confess "Can't close $_[0]: $!";
}
sub FileContents {
my $fh = SafeOpen ("< $_[0]");
my $olddollarslash = $/;
local $/ = undef;
my $contents = <$fh>;
$/ = $olddollarslash;
return $contents;
}
sub WriteStringToFile {
my $fh = SafeOpen ("> $_[0]");
binmode $fh;
print $fh $_[1] or confess "$_[0]: $!\n";
SafeClose $fh;
}
foreach my $file (@ARGV) {
my $changed_p = 0;
my $new_contents = "";
if ($options{"line-mode"}) {
my $fh = SafeOpen $file;
while (<$fh>) {
my $save_line = $_;
eval $code;
$changed_p = 1 if $save_line ne $_;
$new_contents .= $_;
}
} else {
my $orig_contents = $_ = FileContents $file;
eval $code;
if ($_ ne $orig_contents) {
$changed_p = 1;
$new_contents = $_;
}
}
if ($changed_p) {
my $backdir = $options{"backup-dir"};
$backdir = "backup" if !defined ($backdir);
if ($backdir) {
my ($name, $path, $suffix) = fileparse ($file, "");
my $backfulldir = $path . $backdir;
my $backfile = "$backfulldir/$name";
mkdir $backfulldir, 0755 unless -d $backfulldir;
print "modifying $file (original saved in $backfile)\n";
rename $file, $backfile;
}
WriteStringToFile ($file, $new_contents);
}
}
----------------------------------- cut ------------------------------------
In addition to those programs, I needed to fix up a few other
things, particularly relating to the duplicate definitions of
types, now that some types merged with others. Specifically:
1. in lisp.h, removed duplicate declarations of Bytecount. The
changed code should now look like this: (In each code snippet
below, the first and last lines are the same as the original, as
are all lines outside of those lines. That allows you to locate
the section to be replaced, and replace the stuff in that
section, verifying that there isn't anything new added that
would need to be kept.)
--------------------------------- snip -------------------------------------
/* Counts of bytes or chars */
typedef EMACS_INT Bytecount;
typedef EMACS_INT Charcount;
/* Counts of elements */
typedef EMACS_INT Elemcount;
/* Hash codes */
typedef unsigned long Hashcode;
/* ------------------------ dynamic arrays ------------------- */
--------------------------------- snip -------------------------------------
2. in lstream.h, removed duplicate declaration of Bytecount.
Rewrote the comment about this type. The changed code should
now look like this:
--------------------------------- snip -------------------------------------
#endif
/* The have been some arguments over the what the type should be that
specifies a count of bytes in a data block to be written out or read in,
using Lstream_read(), Lstream_write(), and related functions.
Originally it was long, which worked fine; Martin "corrected" these to
size_t and ssize_t on the grounds that this is theoretically cleaner and
is in keeping with the C standards. Unfortunately, this practice is
horribly error-prone due to design flaws in the way that mixed
signed/unsigned arithmetic happens. In fact, by doing this change,
Martin introduced a subtle but fatal error that caused the operation of
sending large mail messages to the SMTP server under Windows to fail.
By putting all values back to be signed, avoiding any signed/unsigned
mixing, the bug immediately went away. The type then in use was
Lstream_Data_Count, so that it be reverted cleanly if a vote came to
that. Now it is Bytecount.
Some earlier comments about why the type must be signed: This MUST BE
SIGNED, since it also is used in functions that return the number of
bytes actually read to or written from in an operation, and these
functions can return -1 to signal error.
Note that the standard Unix read() and write() functions define the
count going in as a size_t, which is UNSIGNED, and the count going
out as an ssize_t, which is SIGNED. This is a horrible design
flaw. Not only is it highly likely to lead to logic errors when a
-1 gets interpreted as a large positive number, but operations are
bound to fail in all sorts of horrible ways when a number in the
upper-half of the size_t range is passed in -- this number is
unrepresentable as an ssize_t, so code that checks to see how many
bytes are actually written (which is mandatory if you are dealing
with certain types of devices) will get completely screwed up.
--ben
*/
typedef enum lstream_buffering
--------------------------------- snip -------------------------------------
3. in dumper.c, there are four places, all inside of switch()
statements, where XD_BYTECOUNT appears twice as a case tag. In
each case, the two case blocks contain identical code, and you
should *REMOVE THE SECOND* and leave the first.
author | ben |
---|---|
date | Thu, 20 Sep 2001 06:31:11 +0000 |
parents | 183866b06e0b |
children | 943eaba38521 |
line wrap: on
line source
/* undo handling for XEmacs. Copyright (C) 1990, 1992, 1993, 1994 Free Software Foundation, Inc. This file is part of XEmacs. XEmacs 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 2, or (at your option) any later version. XEmacs is distributed in the hope that it will be useful, 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. You should have received a copy of the GNU General Public License along with XEmacs; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* Synched up with: FSF 19.28. */ /* This file has been Mule-ized. */ #include <config.h> #include "lisp.h" #include "buffer.h" #include "extents.h" /* Maintained in event-stream.c */ extern Charbpos last_point_position; extern Lisp_Object last_point_position_buffer; /* Extent code needs to know about undo because the behavior of insert() with regard to extents varies depending on whether we are inside an undo or not. */ int inside_undo; /* Last buffer for which undo information was recorded. */ static Lisp_Object last_undo_buffer; Lisp_Object Qinhibit_read_only; /* 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. This ensures we can't run out of space while trying to make an undo-boundary. */ static Lisp_Object pending_boundary; static void undo_boundary (struct buffer *b) { Lisp_Object tem = Fcar (b->undo_list); if (!NILP (tem)) { /* One way or another, cons nil onto the front of the undo list. */ if (CONSP (pending_boundary)) { /* If we have preallocated the cons cell to use here, use that one. */ XCDR (pending_boundary) = b->undo_list; b->undo_list = pending_boundary; pending_boundary = Qnil; } else b->undo_list = Fcons (Qnil, b->undo_list); } } static int undo_prelude (struct buffer *b, int hack_pending_boundary) { if (EQ (b->undo_list, Qt)) return (0); if (NILP (last_undo_buffer) || (BUFFER_BASE_BUFFER (b) != BUFFER_BASE_BUFFER (XBUFFER (last_undo_buffer)))) { undo_boundary (b); XSETBUFFER (last_undo_buffer, b); } /* Allocate a cons cell to be the undo boundary after this command. */ if (hack_pending_boundary && NILP (pending_boundary)) pending_boundary = Fcons (Qnil, Qnil); if (BUF_MODIFF (b) <= BUF_SAVE_MODIFF (b)) { /* Record that an unmodified buffer is about to be changed. Record the file modification date so that when undoing this entry we can tell whether it is obsolete because the file was saved again. */ b->undo_list = Fcons (Fcons (Qt, Fcons (make_int ((b->modtime >> 16) & 0xffff), make_int (b->modtime & 0xffff))), b->undo_list); } return 1; } static Lisp_Object restore_inside_undo (Lisp_Object val) { inside_undo = XINT (val); return val; } /* 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 (struct buffer *b, Charbpos beg, Charcount length) { if (!undo_prelude (b, 1)) return; /* If this is following another insertion and consecutive with it in the buffer, combine the two. */ if (CONSP (b->undo_list)) { Lisp_Object elt; elt = XCAR (b->undo_list); if (CONSP (elt) && INTP (XCAR (elt)) && INTP (XCDR (elt)) && XINT (XCDR (elt)) == beg) { XCDR (elt) = make_int (beg + length); return; } } b->undo_list = Fcons (Fcons (make_int (beg), make_int (beg + length)), b->undo_list); } /* Record that a deletion is about to take place, for LENGTH characters at location BEG. */ void record_delete (struct buffer *b, Charbpos beg, Charcount length) { /* This function can GC */ Lisp_Object sbeg; int at_boundary; if (!undo_prelude (b, 1)) return; at_boundary = (CONSP (b->undo_list) && NILP (XCAR (b->undo_list))); if (BUF_PT (b) == beg + length) sbeg = make_int (-beg); else sbeg = make_int (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 && BUFFERP (last_point_position_buffer) && b == XBUFFER (last_point_position_buffer) && last_point_position != XINT (sbeg)) b->undo_list = Fcons (make_int (last_point_position), b->undo_list); b->undo_list = Fcons (Fcons (make_string_from_buffer (b, beg, length), sbeg), b->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. */ void record_change (struct buffer *b, Charbpos beg, Charcount length) { record_delete (b, beg, length); record_insert (b, beg, length); } /* Record that an EXTENT is about to be attached or detached in its buffer. This works much like a deletion or insertion, except that there's no string. The tricky part is that the buffer we operate on comes from EXTENT. Most extent changes happen as a side effect of string insertion and deletion; this call is solely for Fdetach_extent() and Finsert_extent(). */ void record_extent (Lisp_Object extent, int attached) { Lisp_Object obj = Fextent_object (extent); if (BUFFERP (obj)) { Lisp_Object token; struct buffer *b = XBUFFER (obj); if (!undo_prelude (b, 1)) return; if (attached) token = extent; else token = list3 (extent, Fextent_start_position (extent), Fextent_end_position (extent)); b->undo_list = Fcons (token, b->undo_list); } else return; } #if 0 /* FSFmacs */ /* Record a change in property PROP (whose old value was VAL) for LENGTH characters starting at position BEG in BUFFER. */ record_property_change (Charbpos beg, Charcount length, Lisp_Object prop, Lisp_Object value, Lisp_Object buffer) { Lisp_Object lbeg, lend, entry; struct buffer *b = XBUFFER (buffer); if (!undo_prelude (b, 1)) return; lbeg = make_int (beg); lend = make_int (beg + length); entry = Fcons (Qnil, Fcons (prop, Fcons (value, Fcons (lbeg, lend)))); b->undo_list = Fcons (entry, b->undo_list); } #endif /* FSFmacs */ DEFUN ("undo-boundary", Fundo_boundary, 0, 0, 0, /* 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. */ ()) { if (EQ (current_buffer->undo_list, Qt)) return Qnil; undo_boundary (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-threshold and undo-high-threshold. */ Lisp_Object truncate_undo_list (Lisp_Object list, int minsize, int maxsize) { Lisp_Object prev, next, last_boundary; int size_so_far = 0; if (!(minsize > 0 || maxsize > 0)) return list; prev = Qnil; next = list; last_boundary = Qnil; if (!CONSP (list)) return (list); /* Always preserve at least the most recent undo record. 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 (Lisp_Cons); /* Advance to next element. */ prev = next; next = XCDR (next); } while (CONSP (next) && !NILP (XCAR (next))) { Lisp_Object elt; elt = XCAR (next); /* Add in the space occupied by this element and its chain link. */ size_so_far += sizeof (Lisp_Cons); if (CONSP (elt)) { size_so_far += sizeof (Lisp_Cons); if (STRINGP (XCAR (elt))) size_so_far += (sizeof (Lisp_String) - 1 + XSTRING_LENGTH (XCAR (elt))); } /* Advance to next element. */ prev = next; next = XCDR (next); } if (CONSP (next)) last_boundary = prev; 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, tells us to truncate after it. If its size pushes past the higher threshold MAXSIZE as well, we truncate before it. */ if (NILP (elt)) { if (size_so_far > maxsize && maxsize > 0) break; last_boundary = prev; if (size_so_far > minsize && minsize > 0) break; } /* Add in the space occupied by this element and its chain link. */ size_so_far += sizeof (Lisp_Cons); if (CONSP (elt)) { size_so_far += sizeof (Lisp_Cons); if (STRINGP (XCAR (elt))) size_so_far += (sizeof (Lisp_String) - 1 + XSTRING_LENGTH (XCAR (elt))); } /* Advance to next element. */ prev = next; 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)) { XCDR (last_boundary) = Qnil; return list; } else return Qnil; } DEFUN ("primitive-undo", Fprimitive_undo, 2, 2, 0, /* Undo COUNT records from the front of the list LIST. Return what remains of the list. */ (count, list)) { struct gcpro gcpro1, gcpro2; Lisp_Object next = Qnil; /* This function can GC */ int arg; int speccount = specpdl_depth (); record_unwind_protect (restore_inside_undo, make_int (inside_undo)); inside_undo = 1; #if 0 /* This is a good feature, but would make undo-start unable to do what is expected. */ Lisp_Object tem; /* If the head of the list is a boundary, it is the boundary preceding this command. Get rid of it and don't count it. */ tem = Fcar (list); if (NILP (tem)) list = Fcdr (list); #endif CHECK_INT (count); arg = XINT (count); next = Qnil; GCPRO2 (next, list); /* Don't let read-only properties interfere with undo. */ if (NILP (current_buffer->read_only)) specbind (Qinhibit_read_only, Qt); while (arg > 0) { while (1) { if (NILP (list)) break; else if (!CONSP (list)) goto rotten; next = XCAR (list); list = XCDR (list); /* Exit inner loop at undo boundary. */ if (NILP (next)) break; /* Handle an integer by setting point to that value. */ else if (INTP (next)) BUF_SET_PT (current_buffer, charbpos_clip_to_bounds (BUF_BEGV (current_buffer), XINT (next), BUF_ZV (current_buffer))); else if (CONSP (next)) { Lisp_Object car = XCAR (next); Lisp_Object cdr = XCDR (next); if (EQ (car, Qt)) { /* Element (t high . low) records previous modtime. */ Lisp_Object high, low; int mod_time; if (!CONSP (cdr)) goto rotten; high = XCAR (cdr); low = XCDR (cdr); if (!INTP (high) || !INTP (low)) goto rotten; mod_time = (XINT (high) << 16) + XINT (low); /* If this records an obsolete save (not matching the actual disk file) then don't mark unmodified. */ if (mod_time != current_buffer->modtime) break; #ifdef CLASH_DETECTION Funlock_buffer (); #endif /* CLASH_DETECTION */ /* may GC under ENERGIZE: */ Fset_buffer_modified_p (Qnil, Qnil); } else if (EXTENTP (car)) { /* Element (extent start end) means that EXTENT was detached, and we need to reattach it. */ Lisp_Object extent_obj, start, end; extent_obj = car; start = Fcar (cdr); end = Fcar (Fcdr (cdr)); if (!INTP (start) || !INTP (end)) goto rotten; Fset_extent_endpoints (extent_obj, start, end, Fcurrent_buffer ()); } #if 0 /* FSFmacs */ else if (EQ (car, Qnil)) { /* Element (nil prop val beg . end) is property change. */ Lisp_Object beg, end, prop, val; prop = Fcar (cdr); cdr = Fcdr (cdr); val = Fcar (cdr); cdr = Fcdr (cdr); beg = Fcar (cdr); end = Fcdr (cdr); Fput_text_property (beg, end, prop, val, Qnil); } #endif /* FSFmacs */ else if (INTP (car) && INTP (cdr)) { /* Element (BEG . END) means range was inserted. */ if (XINT (car) < BUF_BEGV (current_buffer) || XINT (cdr) > BUF_ZV (current_buffer)) signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound); /* Set point first thing, so that undoing this undo does not send point back to where it is now. */ Fgoto_char (car, Qnil); Fdelete_region (car, cdr, Qnil); } else if (STRINGP (car) && INTP (cdr)) { /* Element (STRING . POS) means STRING was deleted. */ Lisp_Object membuf = car; int pos = XINT (cdr); if (pos < 0) { if (-pos < BUF_BEGV (current_buffer) || -pos > BUF_ZV (current_buffer)) signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound); BUF_SET_PT (current_buffer, -pos); Finsert (1, &membuf); } else { if (pos < BUF_BEGV (current_buffer) || pos > BUF_ZV (current_buffer)) signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound); BUF_SET_PT (current_buffer, 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. I'm doubtful that this is safe; you could mess up the process-output mark in shell buffers, so until I hear a compelling reason for this change, I'm leaving it out. -jwz */ /* Finsert_before_markers (1, &membuf); */ Finsert (1, &membuf); BUF_SET_PT (current_buffer, pos); } } else { goto rotten; } } else if (EXTENTP (next)) Fdetach_extent (next); else { rotten: signal_continuable_error (Qinvalid_state, "Something rotten in the state of undo", next); } } arg--; } UNGCPRO; return unbind_to (speccount, list); } void syms_of_undo (void) { DEFSUBR (Fprimitive_undo); DEFSUBR (Fundo_boundary); DEFSYMBOL (Qinhibit_read_only); } void reinit_vars_of_undo (void) { inside_undo = 0; } void vars_of_undo (void) { reinit_vars_of_undo (); pending_boundary = Qnil; staticpro (&pending_boundary); last_undo_buffer = Qnil; staticpro (&last_undo_buffer); }