Commit | Line | Data |
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c6953be1 | 1 | /* undo handling for GNU Emacs. |
3a22ee35 | 2 | Copyright (C) 1990, 1993, 1994 Free Software Foundation, Inc. |
c6953be1 JB |
3 | |
4 | This file is part of GNU Emacs. | |
5 | ||
6 | GNU Emacs is distributed in the hope that it will be useful, | |
7 | but WITHOUT ANY WARRANTY. No author or distributor | |
8 | accepts responsibility to anyone for the consequences of using it | |
9 | or for whether it serves any particular purpose or works at all, | |
10 | unless he says so in writing. Refer to the GNU Emacs General Public | |
11 | License for full details. | |
12 | ||
13 | Everyone is granted permission to copy, modify and redistribute | |
14 | GNU Emacs, but only under the conditions described in the | |
15 | GNU Emacs General Public License. A copy of this license is | |
16 | supposed to have been given to you along with GNU Emacs so you | |
17 | can know your rights and responsibilities. It should be in a | |
18 | file named COPYING. Among other things, the copyright notice | |
19 | and this notice must be preserved on all copies. */ | |
20 | ||
21 | ||
18160b98 | 22 | #include <config.h> |
c6953be1 JB |
23 | #include "lisp.h" |
24 | #include "buffer.h" | |
4e665715 | 25 | #include "commands.h" |
c6953be1 JB |
26 | |
27 | /* Last buffer for which undo information was recorded. */ | |
28 | Lisp_Object last_undo_buffer; | |
29 | ||
f87a68b3 RS |
30 | Lisp_Object Qinhibit_read_only; |
31 | ||
c58632fc RS |
32 | /* The first time a command records something for undo. |
33 | it also allocates the undo-boundary object | |
34 | which will be added to the list at the end of the command. | |
35 | This ensures we can't run out of space while trying to make | |
36 | an undo-boundary. */ | |
37 | Lisp_Object pending_boundary; | |
38 | ||
c6953be1 JB |
39 | /* Record an insertion that just happened or is about to happen, |
40 | for LENGTH characters at position BEG. | |
41 | (It is possible to record an insertion before or after the fact | |
42 | because we don't need to record the contents.) */ | |
43 | ||
44 | record_insert (beg, length) | |
53480e99 | 45 | int beg, length; |
c6953be1 JB |
46 | { |
47 | Lisp_Object lbeg, lend; | |
48 | ||
bdbe6f28 RS |
49 | if (EQ (current_buffer->undo_list, Qt)) |
50 | return; | |
51 | ||
c58632fc RS |
52 | /* Allocate a cons cell to be the undo boundary after this command. */ |
53 | if (NILP (pending_boundary)) | |
54 | pending_boundary = Fcons (Qnil, Qnil); | |
55 | ||
c6953be1 JB |
56 | if (current_buffer != XBUFFER (last_undo_buffer)) |
57 | Fundo_boundary (); | |
552bdbcf | 58 | XSETBUFFER (last_undo_buffer, current_buffer); |
c6953be1 | 59 | |
ad9cdce4 | 60 | if (MODIFF <= SAVE_MODIFF) |
c6953be1 JB |
61 | record_first_change (); |
62 | ||
63 | /* If this is following another insertion and consecutive with it | |
64 | in the buffer, combine the two. */ | |
38c0d37c | 65 | if (CONSP (current_buffer->undo_list)) |
c6953be1 JB |
66 | { |
67 | Lisp_Object elt; | |
68 | elt = XCONS (current_buffer->undo_list)->car; | |
38c0d37c KH |
69 | if (CONSP (elt) |
70 | && INTEGERP (XCONS (elt)->car) | |
71 | && INTEGERP (XCONS (elt)->cdr) | |
53480e99 | 72 | && XINT (XCONS (elt)->cdr) == beg) |
c6953be1 | 73 | { |
53480e99 | 74 | XSETINT (XCONS (elt)->cdr, beg + length); |
c6953be1 JB |
75 | return; |
76 | } | |
77 | } | |
78 | ||
53480e99 KH |
79 | XSETFASTINT (lbeg, beg); |
80 | XSETINT (lend, beg + length); | |
213861c7 JB |
81 | current_buffer->undo_list = Fcons (Fcons (lbeg, lend), |
82 | current_buffer->undo_list); | |
c6953be1 JB |
83 | } |
84 | ||
85 | /* Record that a deletion is about to take place, | |
86 | for LENGTH characters at location BEG. */ | |
87 | ||
88 | record_delete (beg, length) | |
89 | int beg, length; | |
90 | { | |
91 | Lisp_Object lbeg, lend, sbeg; | |
e7a8b791 | 92 | int at_boundary; |
c6953be1 | 93 | |
bdbe6f28 RS |
94 | if (EQ (current_buffer->undo_list, Qt)) |
95 | return; | |
96 | ||
c58632fc RS |
97 | /* Allocate a cons cell to be the undo boundary after this command. */ |
98 | if (NILP (pending_boundary)) | |
99 | pending_boundary = Fcons (Qnil, Qnil); | |
100 | ||
c6953be1 JB |
101 | if (current_buffer != XBUFFER (last_undo_buffer)) |
102 | Fundo_boundary (); | |
552bdbcf | 103 | XSETBUFFER (last_undo_buffer, current_buffer); |
c6953be1 | 104 | |
e7a8b791 RS |
105 | at_boundary = (CONSP (current_buffer->undo_list) |
106 | && NILP (XCONS (current_buffer->undo_list)->car)); | |
107 | ||
ad9cdce4 | 108 | if (MODIFF <= SAVE_MODIFF) |
c6953be1 JB |
109 | record_first_change (); |
110 | ||
111 | if (point == beg + length) | |
552bdbcf | 112 | XSETINT (sbeg, -beg); |
c6953be1 | 113 | else |
28b2b116 KH |
114 | XSETFASTINT (sbeg, beg); |
115 | XSETFASTINT (lbeg, beg); | |
116 | XSETFASTINT (lend, beg + length); | |
350bce56 | 117 | |
e7a8b791 RS |
118 | /* If we are just after an undo boundary, and |
119 | point wasn't at start of deleted range, record where it was. */ | |
120 | if (at_boundary | |
121 | && last_point_position != XFASTINT (sbeg) | |
122 | && current_buffer == XBUFFER (last_point_position_buffer)) | |
350bce56 | 123 | current_buffer->undo_list |
4e665715 | 124 | = Fcons (make_number (last_point_position), current_buffer->undo_list); |
350bce56 | 125 | |
c6953be1 JB |
126 | current_buffer->undo_list |
127 | = Fcons (Fcons (Fbuffer_substring (lbeg, lend), sbeg), | |
128 | current_buffer->undo_list); | |
129 | } | |
130 | ||
131 | /* Record that a replacement is about to take place, | |
132 | for LENGTH characters at location BEG. | |
133 | The replacement does not change the number of characters. */ | |
134 | ||
135 | record_change (beg, length) | |
136 | int beg, length; | |
137 | { | |
138 | record_delete (beg, length); | |
139 | record_insert (beg, length); | |
140 | } | |
141 | \f | |
142 | /* Record that an unmodified buffer is about to be changed. | |
143 | Record the file modification date so that when undoing this entry | |
144 | we can tell whether it is obsolete because the file was saved again. */ | |
145 | ||
146 | record_first_change () | |
147 | { | |
148 | Lisp_Object high, low; | |
ad9cdce4 | 149 | struct buffer *base_buffer = current_buffer; |
0736cafe RS |
150 | |
151 | if (EQ (current_buffer->undo_list, Qt)) | |
152 | return; | |
153 | ||
154 | if (current_buffer != XBUFFER (last_undo_buffer)) | |
155 | Fundo_boundary (); | |
552bdbcf | 156 | XSETBUFFER (last_undo_buffer, current_buffer); |
0736cafe | 157 | |
ad9cdce4 RS |
158 | if (base_buffer->base_buffer) |
159 | base_buffer = base_buffer->base_buffer; | |
160 | ||
161 | XSETFASTINT (high, (base_buffer->modtime >> 16) & 0xffff); | |
162 | XSETFASTINT (low, base_buffer->modtime & 0xffff); | |
c6953be1 JB |
163 | current_buffer->undo_list = Fcons (Fcons (Qt, Fcons (high, low)), current_buffer->undo_list); |
164 | } | |
165 | ||
da9319d5 RS |
166 | /* Record a change in property PROP (whose old value was VAL) |
167 | for LENGTH characters starting at position BEG in BUFFER. */ | |
168 | ||
169 | record_property_change (beg, length, prop, value, buffer) | |
170 | int beg, length; | |
171 | Lisp_Object prop, value, buffer; | |
172 | { | |
173 | Lisp_Object lbeg, lend, entry; | |
174 | struct buffer *obuf = current_buffer; | |
175 | int boundary = 0; | |
176 | ||
0736cafe | 177 | if (EQ (XBUFFER (buffer)->undo_list, Qt)) |
bdbe6f28 RS |
178 | return; |
179 | ||
c58632fc RS |
180 | /* Allocate a cons cell to be the undo boundary after this command. */ |
181 | if (NILP (pending_boundary)) | |
182 | pending_boundary = Fcons (Qnil, Qnil); | |
183 | ||
da9319d5 RS |
184 | if (!EQ (buffer, last_undo_buffer)) |
185 | boundary = 1; | |
186 | last_undo_buffer = buffer; | |
187 | ||
da9319d5 RS |
188 | /* Switch temporarily to the buffer that was changed. */ |
189 | current_buffer = XBUFFER (buffer); | |
190 | ||
191 | if (boundary) | |
192 | Fundo_boundary (); | |
193 | ||
ad9cdce4 | 194 | if (MODIFF <= SAVE_MODIFF) |
da9319d5 RS |
195 | record_first_change (); |
196 | ||
552bdbcf KH |
197 | XSETINT (lbeg, beg); |
198 | XSETINT (lend, beg + length); | |
da9319d5 RS |
199 | entry = Fcons (Qnil, Fcons (prop, Fcons (value, Fcons (lbeg, lend)))); |
200 | current_buffer->undo_list = Fcons (entry, current_buffer->undo_list); | |
201 | ||
202 | current_buffer = obuf; | |
203 | } | |
204 | ||
c6953be1 JB |
205 | DEFUN ("undo-boundary", Fundo_boundary, Sundo_boundary, 0, 0, 0, |
206 | "Mark a boundary between units of undo.\n\ | |
207 | An undo command will stop at this point,\n\ | |
208 | but another undo command will undo to the previous boundary.") | |
209 | () | |
210 | { | |
211 | Lisp_Object tem; | |
212 | if (EQ (current_buffer->undo_list, Qt)) | |
213 | return Qnil; | |
214 | tem = Fcar (current_buffer->undo_list); | |
265a9e55 | 215 | if (!NILP (tem)) |
c58632fc RS |
216 | { |
217 | /* One way or another, cons nil onto the front of the undo list. */ | |
218 | if (!NILP (pending_boundary)) | |
219 | { | |
220 | /* If we have preallocated the cons cell to use here, | |
221 | use that one. */ | |
222 | XCONS (pending_boundary)->cdr = current_buffer->undo_list; | |
223 | current_buffer->undo_list = pending_boundary; | |
224 | pending_boundary = Qnil; | |
225 | } | |
226 | else | |
227 | current_buffer->undo_list = Fcons (Qnil, current_buffer->undo_list); | |
228 | } | |
c6953be1 JB |
229 | return Qnil; |
230 | } | |
231 | ||
232 | /* At garbage collection time, make an undo list shorter at the end, | |
233 | returning the truncated list. | |
234 | MINSIZE and MAXSIZE are the limits on size allowed, as described below. | |
f06cd136 JB |
235 | In practice, these are the values of undo-limit and |
236 | undo-strong-limit. */ | |
c6953be1 JB |
237 | |
238 | Lisp_Object | |
239 | truncate_undo_list (list, minsize, maxsize) | |
240 | Lisp_Object list; | |
241 | int minsize, maxsize; | |
242 | { | |
243 | Lisp_Object prev, next, last_boundary; | |
244 | int size_so_far = 0; | |
245 | ||
246 | prev = Qnil; | |
247 | next = list; | |
248 | last_boundary = Qnil; | |
249 | ||
250 | /* Always preserve at least the most recent undo record. | |
181a18b1 JB |
251 | If the first element is an undo boundary, skip past it. |
252 | ||
253 | Skip, skip, skip the undo, skip, skip, skip the undo, | |
07627b5d JB |
254 | Skip, skip, skip the undo, skip to the undo bound'ry. |
255 | (Get it? "Skip to my Loo?") */ | |
38c0d37c | 256 | if (CONSP (next) && NILP (XCONS (next)->car)) |
c6953be1 JB |
257 | { |
258 | /* Add in the space occupied by this element and its chain link. */ | |
259 | size_so_far += sizeof (struct Lisp_Cons); | |
260 | ||
261 | /* Advance to next element. */ | |
262 | prev = next; | |
263 | next = XCONS (next)->cdr; | |
264 | } | |
38c0d37c | 265 | while (CONSP (next) && ! NILP (XCONS (next)->car)) |
c6953be1 JB |
266 | { |
267 | Lisp_Object elt; | |
268 | elt = XCONS (next)->car; | |
269 | ||
270 | /* Add in the space occupied by this element and its chain link. */ | |
271 | size_so_far += sizeof (struct Lisp_Cons); | |
38c0d37c | 272 | if (CONSP (elt)) |
c6953be1 JB |
273 | { |
274 | size_so_far += sizeof (struct Lisp_Cons); | |
38c0d37c | 275 | if (STRINGP (XCONS (elt)->car)) |
c6953be1 JB |
276 | size_so_far += (sizeof (struct Lisp_String) - 1 |
277 | + XSTRING (XCONS (elt)->car)->size); | |
278 | } | |
279 | ||
280 | /* Advance to next element. */ | |
281 | prev = next; | |
282 | next = XCONS (next)->cdr; | |
283 | } | |
38c0d37c | 284 | if (CONSP (next)) |
c6953be1 JB |
285 | last_boundary = prev; |
286 | ||
38c0d37c | 287 | while (CONSP (next)) |
c6953be1 JB |
288 | { |
289 | Lisp_Object elt; | |
290 | elt = XCONS (next)->car; | |
291 | ||
292 | /* When we get to a boundary, decide whether to truncate | |
293 | either before or after it. The lower threshold, MINSIZE, | |
294 | tells us to truncate after it. If its size pushes past | |
295 | the higher threshold MAXSIZE as well, we truncate before it. */ | |
265a9e55 | 296 | if (NILP (elt)) |
c6953be1 JB |
297 | { |
298 | if (size_so_far > maxsize) | |
299 | break; | |
300 | last_boundary = prev; | |
301 | if (size_so_far > minsize) | |
302 | break; | |
303 | } | |
304 | ||
305 | /* Add in the space occupied by this element and its chain link. */ | |
306 | size_so_far += sizeof (struct Lisp_Cons); | |
38c0d37c | 307 | if (CONSP (elt)) |
c6953be1 JB |
308 | { |
309 | size_so_far += sizeof (struct Lisp_Cons); | |
38c0d37c | 310 | if (STRINGP (XCONS (elt)->car)) |
c6953be1 JB |
311 | size_so_far += (sizeof (struct Lisp_String) - 1 |
312 | + XSTRING (XCONS (elt)->car)->size); | |
313 | } | |
314 | ||
315 | /* Advance to next element. */ | |
316 | prev = next; | |
317 | next = XCONS (next)->cdr; | |
318 | } | |
319 | ||
320 | /* If we scanned the whole list, it is short enough; don't change it. */ | |
265a9e55 | 321 | if (NILP (next)) |
c6953be1 JB |
322 | return list; |
323 | ||
324 | /* Truncate at the boundary where we decided to truncate. */ | |
265a9e55 | 325 | if (!NILP (last_boundary)) |
c6953be1 JB |
326 | { |
327 | XCONS (last_boundary)->cdr = Qnil; | |
328 | return list; | |
329 | } | |
330 | else | |
331 | return Qnil; | |
332 | } | |
333 | \f | |
334 | DEFUN ("primitive-undo", Fprimitive_undo, Sprimitive_undo, 2, 2, 0, | |
335 | "Undo N records from the front of the list LIST.\n\ | |
336 | Return what remains of the list.") | |
063fb61f RS |
337 | (n, list) |
338 | Lisp_Object n, list; | |
c6953be1 | 339 | { |
de65837b KH |
340 | struct gcpro gcpro1, gcpro2; |
341 | Lisp_Object next; | |
f87a68b3 | 342 | int count = specpdl_ptr - specpdl; |
de65837b | 343 | register int arg; |
c6953be1 JB |
344 | #if 0 /* This is a good feature, but would make undo-start |
345 | unable to do what is expected. */ | |
346 | Lisp_Object tem; | |
347 | ||
348 | /* If the head of the list is a boundary, it is the boundary | |
349 | preceding this command. Get rid of it and don't count it. */ | |
350 | tem = Fcar (list); | |
265a9e55 | 351 | if (NILP (tem)) |
c6953be1 JB |
352 | list = Fcdr (list); |
353 | #endif | |
354 | ||
de65837b KH |
355 | CHECK_NUMBER (n, 0); |
356 | arg = XINT (n); | |
357 | next = Qnil; | |
358 | GCPRO2 (next, list); | |
359 | ||
f87a68b3 RS |
360 | /* Don't let read-only properties interfere with undo. */ |
361 | if (NILP (current_buffer->read_only)) | |
362 | specbind (Qinhibit_read_only, Qt); | |
363 | ||
c6953be1 JB |
364 | while (arg > 0) |
365 | { | |
366 | while (1) | |
367 | { | |
c6953be1 JB |
368 | next = Fcar (list); |
369 | list = Fcdr (list); | |
350bce56 | 370 | /* Exit inner loop at undo boundary. */ |
265a9e55 | 371 | if (NILP (next)) |
c6953be1 | 372 | break; |
350bce56 | 373 | /* Handle an integer by setting point to that value. */ |
38c0d37c | 374 | if (INTEGERP (next)) |
350bce56 | 375 | SET_PT (clip_to_bounds (BEGV, XINT (next), ZV)); |
38c0d37c | 376 | else if (CONSP (next)) |
c6953be1 | 377 | { |
350bce56 RS |
378 | Lisp_Object car, cdr; |
379 | ||
380 | car = Fcar (next); | |
381 | cdr = Fcdr (next); | |
382 | if (EQ (car, Qt)) | |
c6953be1 | 383 | { |
350bce56 RS |
384 | /* Element (t high . low) records previous modtime. */ |
385 | Lisp_Object high, low; | |
386 | int mod_time; | |
ad9cdce4 | 387 | struct buffer *base_buffer = current_buffer; |
350bce56 RS |
388 | |
389 | high = Fcar (cdr); | |
390 | low = Fcdr (cdr); | |
d8552b2f | 391 | mod_time = (XFASTINT (high) << 16) + XFASTINT (low); |
ad9cdce4 RS |
392 | |
393 | if (current_buffer->base_buffer) | |
394 | base_buffer = current_buffer->base_buffer; | |
395 | ||
350bce56 RS |
396 | /* If this records an obsolete save |
397 | (not matching the actual disk file) | |
398 | then don't mark unmodified. */ | |
ad9cdce4 | 399 | if (mod_time != base_buffer->modtime) |
103dcb38 | 400 | continue; |
e6dd6080 | 401 | #ifdef CLASH_DETECTION |
350bce56 | 402 | Funlock_buffer (); |
e6dd6080 | 403 | #endif /* CLASH_DETECTION */ |
350bce56 | 404 | Fset_buffer_modified_p (Qnil); |
c6953be1 | 405 | } |
d8552b2f RS |
406 | #ifdef USE_TEXT_PROPERTIES |
407 | else if (EQ (car, Qnil)) | |
da9319d5 | 408 | { |
d8552b2f | 409 | /* Element (nil prop val beg . end) is property change. */ |
da9319d5 RS |
410 | Lisp_Object beg, end, prop, val; |
411 | ||
412 | prop = Fcar (cdr); | |
413 | cdr = Fcdr (cdr); | |
414 | val = Fcar (cdr); | |
415 | cdr = Fcdr (cdr); | |
416 | beg = Fcar (cdr); | |
417 | end = Fcdr (cdr); | |
418 | ||
419 | Fput_text_property (beg, end, prop, val, Qnil); | |
420 | } | |
d8552b2f | 421 | #endif /* USE_TEXT_PROPERTIES */ |
38c0d37c | 422 | else if (INTEGERP (car) && INTEGERP (cdr)) |
c6953be1 | 423 | { |
350bce56 RS |
424 | /* Element (BEG . END) means range was inserted. */ |
425 | Lisp_Object end; | |
426 | ||
427 | if (XINT (car) < BEGV | |
428 | || XINT (cdr) > ZV) | |
c6953be1 | 429 | error ("Changes to be undone are outside visible portion of buffer"); |
f28f04cc RS |
430 | /* Set point first thing, so that undoing this undo |
431 | does not send point back to where it is now. */ | |
350bce56 | 432 | Fgoto_char (car); |
f28f04cc | 433 | Fdelete_region (car, cdr); |
350bce56 | 434 | } |
38c0d37c | 435 | else if (STRINGP (car) && INTEGERP (cdr)) |
350bce56 RS |
436 | { |
437 | /* Element (STRING . POS) means STRING was deleted. */ | |
438 | Lisp_Object membuf; | |
439 | int pos = XINT (cdr); | |
440 | ||
441 | membuf = car; | |
442 | if (pos < 0) | |
443 | { | |
444 | if (-pos < BEGV || -pos > ZV) | |
445 | error ("Changes to be undone are outside visible portion of buffer"); | |
446 | SET_PT (-pos); | |
447 | Finsert (1, &membuf); | |
448 | } | |
449 | else | |
450 | { | |
451 | if (pos < BEGV || pos > ZV) | |
452 | error ("Changes to be undone are outside visible portion of buffer"); | |
453 | SET_PT (pos); | |
454 | ||
455 | /* Insert before markers so that if the mark is | |
456 | currently on the boundary of this deletion, it | |
457 | ends up on the other side of the now-undeleted | |
458 | text from point. Since undo doesn't even keep | |
459 | track of the mark, this isn't really necessary, | |
460 | but it may lead to better behavior in certain | |
461 | situations. */ | |
462 | Finsert_before_markers (1, &membuf); | |
463 | SET_PT (pos); | |
464 | } | |
c6953be1 JB |
465 | } |
466 | } | |
467 | } | |
468 | arg--; | |
469 | } | |
470 | ||
de65837b | 471 | UNGCPRO; |
f87a68b3 | 472 | return unbind_to (count, list); |
c6953be1 JB |
473 | } |
474 | ||
475 | syms_of_undo () | |
476 | { | |
f87a68b3 RS |
477 | Qinhibit_read_only = intern ("inhibit-read-only"); |
478 | staticpro (&Qinhibit_read_only); | |
479 | ||
c58632fc RS |
480 | pending_boundary = Qnil; |
481 | staticpro (&pending_boundary); | |
482 | ||
c6953be1 JB |
483 | defsubr (&Sprimitive_undo); |
484 | defsubr (&Sundo_boundary); | |
485 | } |