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comparison src/undo.c @ 428:3ecd8885ac67 r21-2-22

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Import from CVS: tag r21-2-22
author cvs
date Mon, 13 Aug 2007 11:28:15 +0200
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427:0a0253eac470 428:3ecd8885ac67
1 /* undo handling for XEmacs.
2 Copyright (C) 1990, 1992, 1993, 1994 Free Software Foundation, Inc.
3
4 This file is part of XEmacs.
5
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
20
21 /* Synched up with: FSF 19.28. */
22
23 /* This file has been Mule-ized. */
24
25 #include <config.h>
26 #include "lisp.h"
27 #include "buffer.h"
28 #include "extents.h"
29
30 /* Maintained in event-stream.c */
31 extern Bufpos last_point_position;
32 extern Lisp_Object last_point_position_buffer;
33
34 /* Extent code needs to know about undo because the behavior of insert()
35 with regard to extents varies depending on whether we are inside
36 an undo or not. */
37 int inside_undo;
38
39 /* Last buffer for which undo information was recorded. */
40 static Lisp_Object last_undo_buffer;
41
42 Lisp_Object Qinhibit_read_only;
43
44 /* The first time a command records something for undo.
45 it also allocates the undo-boundary object
46 which will be added to the list at the end of the command.
47 This ensures we can't run out of space while trying to make
48 an undo-boundary. */
49 static Lisp_Object pending_boundary;
50
51 static void
52 undo_boundary (struct buffer *b)
53 {
54 Lisp_Object tem = Fcar (b->undo_list);
55 if (!NILP (tem))
56 {
57 /* One way or another, cons nil onto the front of the undo list. */
58 if (CONSP (pending_boundary))
59 {
60 /* If we have preallocated the cons cell to use here,
61 use that one. */
62 XCDR (pending_boundary) = b->undo_list;
63 b->undo_list = pending_boundary;
64 pending_boundary = Qnil;
65 }
66 else
67 b->undo_list = Fcons (Qnil, b->undo_list);
68 }
69 }
70
71
72 static int
73 undo_prelude (struct buffer *b, int hack_pending_boundary)
74 {
75 if (EQ (b->undo_list, Qt))
76 return (0);
77
78 if (NILP (last_undo_buffer)
79 || (BUFFER_BASE_BUFFER (b)
80 != BUFFER_BASE_BUFFER (XBUFFER (last_undo_buffer))))
81 {
82 undo_boundary (b);
83 XSETBUFFER (last_undo_buffer, b);
84 }
85
86 /* Allocate a cons cell to be the undo boundary after this command. */
87 if (hack_pending_boundary && NILP (pending_boundary))
88 pending_boundary = Fcons (Qnil, Qnil);
89
90 if (BUF_MODIFF (b) <= BUF_SAVE_MODIFF (b))
91 {
92 /* Record that an unmodified buffer is about to be changed.
93 Record the file modification date so that when undoing this
94 entry we can tell whether it is obsolete because the file was
95 saved again. */
96 b->undo_list
97 = Fcons (Fcons (Qt,
98 Fcons (make_int ((b->modtime >> 16) & 0xffff),
99 make_int (b->modtime & 0xffff))),
100 b->undo_list);
101 }
102 return 1;
103 }
104
105
106
107 static Lisp_Object
108 restore_inside_undo (Lisp_Object val)
109 {
110 inside_undo = XINT (val);
111 return val;
112 }
113
114
115 /* Record an insertion that just happened or is about to happen,
116 for LENGTH characters at position BEG.
117 (It is possible to record an insertion before or after the fact
118 because we don't need to record the contents.) */
119
120 void
121 record_insert (struct buffer *b, Bufpos beg, Charcount length)
122 {
123 if (!undo_prelude (b, 1))
124 return;
125
126 /* If this is following another insertion and consecutive with it
127 in the buffer, combine the two. */
128 if (CONSP (b->undo_list))
129 {
130 Lisp_Object elt;
131 elt = XCAR (b->undo_list);
132 if (CONSP (elt)
133 && INTP (XCAR (elt))
134 && INTP (XCDR (elt))
135 && XINT (XCDR (elt)) == beg)
136 {
137 XCDR (elt) = make_int (beg + length);
138 return;
139 }
140 }
141
142 b->undo_list = Fcons (Fcons (make_int (beg),
143 make_int (beg + length)),
144 b->undo_list);
145 }
146
147 /* Record that a deletion is about to take place,
148 for LENGTH characters at location BEG. */
149
150 void
151 record_delete (struct buffer *b, Bufpos beg, Charcount length)
152 {
153 /* This function can GC */
154 Lisp_Object sbeg;
155 int at_boundary;
156
157 if (!undo_prelude (b, 1))
158 return;
159
160 at_boundary = (CONSP (b->undo_list)
161 && NILP (XCAR (b->undo_list)));
162
163 if (BUF_PT (b) == beg + length)
164 sbeg = make_int (-beg);
165 else
166 sbeg = make_int (beg);
167
168 /* If we are just after an undo boundary, and
169 point wasn't at start of deleted range, record where it was. */
170 if (at_boundary
171 && BUFFERP (last_point_position_buffer)
172 && b == XBUFFER (last_point_position_buffer)
173 && last_point_position != XINT (sbeg))
174 b->undo_list = Fcons (make_int (last_point_position), b->undo_list);
175
176 b->undo_list = Fcons (Fcons (make_string_from_buffer (b, beg,
177 length),
178 sbeg),
179 b->undo_list);
180 }
181
182 /* Record that a replacement is about to take place,
183 for LENGTH characters at location BEG.
184 The replacement does not change the number of characters. */
185
186 void
187 record_change (struct buffer *b, Bufpos beg, Charcount length)
188 {
189 record_delete (b, beg, length);
190 record_insert (b, beg, length);
191 }
192
193 /* Record that an EXTENT is about to be attached or detached in its buffer.
194 This works much like a deletion or insertion, except that there's no string.
195 The tricky part is that the buffer we operate on comes from EXTENT.
196 Most extent changes happen as a side effect of string insertion and
197 deletion; this call is solely for Fdetach_extent() and Finsert_extent().
198 */
199 void
200 record_extent (Lisp_Object extent, int attached)
201 {
202 Lisp_Object obj = Fextent_object (extent);
203
204 if (BUFFERP (obj))
205 {
206 Lisp_Object token;
207 struct buffer *b = XBUFFER (obj);
208 if (!undo_prelude (b, 1))
209 return;
210 if (attached)
211 token = extent;
212 else
213 token = list3 (extent, Fextent_start_position (extent),
214 Fextent_end_position (extent));
215 b->undo_list = Fcons (token, b->undo_list);
216 }
217 else
218 return;
219 }
220
221 #if 0 /* FSFmacs */
222 /* Record a change in property PROP (whose old value was VAL)
223 for LENGTH characters starting at position BEG in BUFFER. */
224
225 record_property_change (Bufpos beg, Charcount length,
226 Lisp_Object prop, Lisp_Object value,
227 Lisp_Object buffer)
228 {
229 Lisp_Object lbeg, lend, entry;
230 struct buffer *b = XBUFFER (buffer);
231
232 if (!undo_prelude (b, 1))
233 return;
234
235 lbeg = make_int (beg);
236 lend = make_int (beg + length);
237 entry = Fcons (Qnil, Fcons (prop, Fcons (value, Fcons (lbeg, lend))));
238 b->undo_list = Fcons (entry, b->undo_list);
239 }
240 #endif /* FSFmacs */
241
242
243 DEFUN ("undo-boundary", Fundo_boundary, 0, 0, 0, /*
244 Mark a boundary between units of undo.
245 An undo command will stop at this point,
246 but another undo command will undo to the previous boundary.
247 */
248 ())
249 {
250 if (EQ (current_buffer->undo_list, Qt))
251 return Qnil;
252 undo_boundary (current_buffer);
253 return Qnil;
254 }
255
256 /* At garbage collection time, make an undo list shorter at the end,
257 returning the truncated list.
258 MINSIZE and MAXSIZE are the limits on size allowed, as described below.
259 In practice, these are the values of undo-threshold and
260 undo-high-threshold. */
261
262 Lisp_Object
263 truncate_undo_list (Lisp_Object list, int minsize, int maxsize)
264 {
265 Lisp_Object prev, next, last_boundary;
266 int size_so_far = 0;
267
268 if (!(minsize > 0 || maxsize > 0))
269 return list;
270
271 prev = Qnil;
272 next = list;
273 last_boundary = Qnil;
274
275 if (!CONSP (list))
276 return (list);
277
278 /* Always preserve at least the most recent undo record.
279 If the first element is an undo boundary, skip past it. */
280 if (CONSP (next)
281 && NILP (XCAR (next)))
282 {
283 /* Add in the space occupied by this element and its chain link. */
284 size_so_far += sizeof (struct Lisp_Cons);
285
286 /* Advance to next element. */
287 prev = next;
288 next = XCDR (next);
289 }
290 while (CONSP (next)
291 && !NILP (XCAR (next)))
292 {
293 Lisp_Object elt;
294 elt = XCAR (next);
295
296 /* Add in the space occupied by this element and its chain link. */
297 size_so_far += sizeof (struct Lisp_Cons);
298 if (CONSP (elt))
299 {
300 size_so_far += sizeof (struct Lisp_Cons);
301 if (STRINGP (XCAR (elt)))
302 size_so_far += (sizeof (struct Lisp_String) - 1
303 + XSTRING_LENGTH (XCAR (elt)));
304 }
305
306 /* Advance to next element. */
307 prev = next;
308 next = XCDR (next);
309 }
310 if (CONSP (next))
311 last_boundary = prev;
312
313 while (CONSP (next))
314 {
315 Lisp_Object elt;
316 elt = XCAR (next);
317
318 /* When we get to a boundary, decide whether to truncate
319 either before or after it. The lower threshold, MINSIZE,
320 tells us to truncate after it. If its size pushes past
321 the higher threshold MAXSIZE as well, we truncate before it. */
322 if (NILP (elt))
323 {
324 if (size_so_far > maxsize && maxsize > 0)
325 break;
326 last_boundary = prev;
327 if (size_so_far > minsize && minsize > 0)
328 break;
329 }
330
331 /* Add in the space occupied by this element and its chain link. */
332 size_so_far += sizeof (struct Lisp_Cons);
333 if (CONSP (elt))
334 {
335 size_so_far += sizeof (struct Lisp_Cons);
336 if (STRINGP (XCAR (elt)))
337 size_so_far += (sizeof (struct Lisp_String) - 1
338 + XSTRING_LENGTH (XCAR (elt)));
339 }
340
341 /* Advance to next element. */
342 prev = next;
343 next = XCDR (next);
344 }
345
346 /* If we scanned the whole list, it is short enough; don't change it. */
347 if (NILP (next))
348 return list;
349
350 /* Truncate at the boundary where we decided to truncate. */
351 if (!NILP (last_boundary))
352 {
353 XCDR (last_boundary) = Qnil;
354 return list;
355 }
356 else
357 return Qnil;
358 }
359
360 DEFUN ("primitive-undo", Fprimitive_undo, 2, 2, 0, /*
361 Undo COUNT records from the front of the list LIST.
362 Return what remains of the list.
363 */
364 (count, list))
365 {
366 struct gcpro gcpro1, gcpro2;
367 Lisp_Object next = Qnil;
368 /* This function can GC */
369 int arg;
370 int speccount = specpdl_depth ();
371
372 record_unwind_protect (restore_inside_undo, make_int (inside_undo));
373 inside_undo = 1;
374
375 #if 0 /* This is a good feature, but would make undo-start
376 unable to do what is expected. */
377 Lisp_Object tem;
378
379 /* If the head of the list is a boundary, it is the boundary
380 preceding this command. Get rid of it and don't count it. */
381 tem = Fcar (list);
382 if (NILP (tem))
383 list = Fcdr (list);
384 #endif
385
386 CHECK_INT (count);
387 arg = XINT (count);
388 next = Qnil;
389 GCPRO2 (next, list);
390
391 /* Don't let read-only properties interfere with undo. */
392 if (NILP (current_buffer->read_only))
393 specbind (Qinhibit_read_only, Qt);
394
395 while (arg > 0)
396 {
397 while (1)
398 {
399 if (NILP (list))
400 break;
401 else if (!CONSP (list))
402 goto rotten;
403 next = XCAR (list);
404 list = XCDR (list);
405 /* Exit inner loop at undo boundary. */
406 if (NILP (next))
407 break;
408 /* Handle an integer by setting point to that value. */
409 else if (INTP (next))
410 BUF_SET_PT (current_buffer,
411 bufpos_clip_to_bounds (BUF_BEGV (current_buffer),
412 XINT (next),
413 BUF_ZV (current_buffer)));
414 else if (CONSP (next))
415 {
416 Lisp_Object car = XCAR (next);
417 Lisp_Object cdr = XCDR (next);
418
419 if (EQ (car, Qt))
420 {
421 /* Element (t high . low) records previous modtime. */
422 Lisp_Object high, low;
423 int mod_time;
424 if (!CONSP (cdr)) goto rotten;
425 high = XCAR (cdr);
426 low = XCDR (cdr);
427 if (!INTP (high) || !INTP (low)) goto rotten;
428 mod_time = (XINT (high) << 16) + XINT (low);
429 /* If this records an obsolete save
430 (not matching the actual disk file)
431 then don't mark unmodified. */
432 if (mod_time != current_buffer->modtime)
433 break;
434 #ifdef CLASH_DETECTION
435 Funlock_buffer ();
436 #endif /* CLASH_DETECTION */
437 /* may GC under ENERGIZE: */
438 Fset_buffer_modified_p (Qnil, Qnil);
439 }
440 else if (EXTENTP (car))
441 {
442 /* Element (extent start end) means that EXTENT was
443 detached, and we need to reattach it. */
444 Lisp_Object extent_obj, start, end;
445
446 extent_obj = car;
447 start = Fcar (cdr);
448 end = Fcar (Fcdr (cdr));
449
450 if (!INTP (start) || !INTP (end))
451 goto rotten;
452 Fset_extent_endpoints (extent_obj, start, end,
453 Fcurrent_buffer ());
454 }
455 #if 0 /* FSFmacs */
456 else if (EQ (car, Qnil))
457 {
458 /* Element (nil prop val beg . end) is property change. */
459 Lisp_Object beg, end, prop, val;
460
461 prop = Fcar (cdr);
462 cdr = Fcdr (cdr);
463 val = Fcar (cdr);
464 cdr = Fcdr (cdr);
465 beg = Fcar (cdr);
466 end = Fcdr (cdr);
467
468 Fput_text_property (beg, end, prop, val, Qnil);
469 }
470 #endif /* FSFmacs */
471 else if (INTP (car) && INTP (cdr))
472 {
473 /* Element (BEG . END) means range was inserted. */
474
475 if (XINT (car) < BUF_BEGV (current_buffer)
476 || XINT (cdr) > BUF_ZV (current_buffer))
477 error ("Changes to be undone are outside visible portion of buffer");
478 /* Set point first thing, so that undoing this undo
479 does not send point back to where it is now. */
480 Fgoto_char (car, Qnil);
481 Fdelete_region (car, cdr, Qnil);
482 }
483 else if (STRINGP (car) && INTP (cdr))
484 {
485 /* Element (STRING . POS) means STRING was deleted. */
486 Lisp_Object membuf = car;
487 int pos = XINT (cdr);
488
489 if (pos < 0)
490 {
491 if (-pos < BUF_BEGV (current_buffer) || -pos > BUF_ZV (current_buffer))
492 error ("Changes to be undone are outside visible portion of buffer");
493 BUF_SET_PT (current_buffer, -pos);
494 Finsert (1, &membuf);
495 }
496 else
497 {
498 if (pos < BUF_BEGV (current_buffer) || pos > BUF_ZV (current_buffer))
499 error ("Changes to be undone are outside visible portion of buffer");
500 BUF_SET_PT (current_buffer, pos);
501
502 /* Insert before markers so that if the mark is
503 currently on the boundary of this deletion, it
504 ends up on the other side of the now-undeleted
505 text from point. Since undo doesn't even keep
506 track of the mark, this isn't really necessary,
507 but it may lead to better behavior in certain
508 situations.
509
510 I'm doubtful that this is safe; you could mess
511 up the process-output mark in shell buffers, so
512 until I hear a compelling reason for this change,
513 I'm leaving it out. -jwz
514 */
515 /* Finsert_before_markers (1, &membuf); */
516 Finsert (1, &membuf);
517 BUF_SET_PT (current_buffer, pos);
518 }
519 }
520 else
521 {
522 goto rotten;
523 }
524 }
525 else if (EXTENTP (next))
526 Fdetach_extent (next);
527 else
528 {
529 rotten:
530 signal_simple_continuable_error
531 ("Something rotten in the state of undo", next);
532 }
533 }
534 arg--;
535 }
536
537 UNGCPRO;
538 return unbind_to (speccount, list);
539 }
540
541 void
542 syms_of_undo (void)
543 {
544 DEFSUBR (Fprimitive_undo);
545 DEFSUBR (Fundo_boundary);
546 defsymbol (&Qinhibit_read_only, "inhibit-read-only");
547 }
548
549 void
550 reinit_vars_of_undo (void)
551 {
552 inside_undo = 0;
553 }
554
555 void
556 vars_of_undo (void)
557 {
558 reinit_vars_of_undo ();
559
560 pending_boundary = Qnil;
561 staticpro (&pending_boundary);
562 last_undo_buffer = Qnil;
563 staticpro (&last_undo_buffer);
564 }