Commit | Line | Data |
---|---|---|
c6953be1 | 1 | /* undo handling for GNU Emacs. |
c6c5df7f | 2 | Copyright (C) 1990, 1993 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) | |
45 | Lisp_Object beg, length; | |
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 (); | |
58 | XSET (last_undo_buffer, Lisp_Buffer, current_buffer); | |
59 | ||
c6953be1 JB |
60 | if (MODIFF <= current_buffer->save_modified) |
61 | record_first_change (); | |
62 | ||
63 | /* If this is following another insertion and consecutive with it | |
64 | in the buffer, combine the two. */ | |
65 | if (XTYPE (current_buffer->undo_list) == Lisp_Cons) | |
66 | { | |
67 | Lisp_Object elt; | |
68 | elt = XCONS (current_buffer->undo_list)->car; | |
69 | if (XTYPE (elt) == Lisp_Cons | |
70 | && XTYPE (XCONS (elt)->car) == Lisp_Int | |
71 | && XTYPE (XCONS (elt)->cdr) == Lisp_Int | |
213861c7 | 72 | && XINT (XCONS (elt)->cdr) == XINT (beg)) |
c6953be1 | 73 | { |
213861c7 | 74 | XSETINT (XCONS (elt)->cdr, XINT (beg) + XINT (length)); |
c6953be1 JB |
75 | return; |
76 | } | |
77 | } | |
78 | ||
213861c7 JB |
79 | lbeg = beg; |
80 | XSET (lend, Lisp_Int, XINT (beg) + XINT (length)); | |
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; | |
92 | ||
bdbe6f28 RS |
93 | if (EQ (current_buffer->undo_list, Qt)) |
94 | return; | |
95 | ||
c58632fc RS |
96 | /* Allocate a cons cell to be the undo boundary after this command. */ |
97 | if (NILP (pending_boundary)) | |
98 | pending_boundary = Fcons (Qnil, Qnil); | |
99 | ||
c6953be1 JB |
100 | if (current_buffer != XBUFFER (last_undo_buffer)) |
101 | Fundo_boundary (); | |
102 | XSET (last_undo_buffer, Lisp_Buffer, current_buffer); | |
103 | ||
c6953be1 JB |
104 | if (MODIFF <= current_buffer->save_modified) |
105 | record_first_change (); | |
106 | ||
107 | if (point == beg + length) | |
108 | XSET (sbeg, Lisp_Int, -beg); | |
109 | else | |
110 | XFASTINT (sbeg) = beg; | |
111 | XFASTINT (lbeg) = beg; | |
112 | XFASTINT (lend) = beg + length; | |
350bce56 | 113 | |
4e665715 KH |
114 | /* If point wasn't at start of deleted range, record where it was. */ |
115 | if (last_point_position != XFASTINT (sbeg)) | |
350bce56 | 116 | current_buffer->undo_list |
4e665715 | 117 | = Fcons (make_number (last_point_position), current_buffer->undo_list); |
350bce56 | 118 | |
c6953be1 JB |
119 | current_buffer->undo_list |
120 | = Fcons (Fcons (Fbuffer_substring (lbeg, lend), sbeg), | |
121 | current_buffer->undo_list); | |
122 | } | |
123 | ||
124 | /* Record that a replacement is about to take place, | |
125 | for LENGTH characters at location BEG. | |
126 | The replacement does not change the number of characters. */ | |
127 | ||
128 | record_change (beg, length) | |
129 | int beg, length; | |
130 | { | |
131 | record_delete (beg, length); | |
132 | record_insert (beg, length); | |
133 | } | |
134 | \f | |
135 | /* Record that an unmodified buffer is about to be changed. | |
136 | Record the file modification date so that when undoing this entry | |
137 | we can tell whether it is obsolete because the file was saved again. */ | |
138 | ||
139 | record_first_change () | |
140 | { | |
141 | Lisp_Object high, low; | |
0736cafe RS |
142 | |
143 | if (EQ (current_buffer->undo_list, Qt)) | |
144 | return; | |
145 | ||
146 | if (current_buffer != XBUFFER (last_undo_buffer)) | |
147 | Fundo_boundary (); | |
148 | XSET (last_undo_buffer, Lisp_Buffer, current_buffer); | |
149 | ||
c6953be1 JB |
150 | XFASTINT (high) = (current_buffer->modtime >> 16) & 0xffff; |
151 | XFASTINT (low) = current_buffer->modtime & 0xffff; | |
152 | current_buffer->undo_list = Fcons (Fcons (Qt, Fcons (high, low)), current_buffer->undo_list); | |
153 | } | |
154 | ||
da9319d5 RS |
155 | /* Record a change in property PROP (whose old value was VAL) |
156 | for LENGTH characters starting at position BEG in BUFFER. */ | |
157 | ||
158 | record_property_change (beg, length, prop, value, buffer) | |
159 | int beg, length; | |
160 | Lisp_Object prop, value, buffer; | |
161 | { | |
162 | Lisp_Object lbeg, lend, entry; | |
163 | struct buffer *obuf = current_buffer; | |
164 | int boundary = 0; | |
165 | ||
0736cafe | 166 | if (EQ (XBUFFER (buffer)->undo_list, Qt)) |
bdbe6f28 RS |
167 | return; |
168 | ||
c58632fc RS |
169 | /* Allocate a cons cell to be the undo boundary after this command. */ |
170 | if (NILP (pending_boundary)) | |
171 | pending_boundary = Fcons (Qnil, Qnil); | |
172 | ||
da9319d5 RS |
173 | if (!EQ (buffer, last_undo_buffer)) |
174 | boundary = 1; | |
175 | last_undo_buffer = buffer; | |
176 | ||
da9319d5 RS |
177 | /* Switch temporarily to the buffer that was changed. */ |
178 | current_buffer = XBUFFER (buffer); | |
179 | ||
180 | if (boundary) | |
181 | Fundo_boundary (); | |
182 | ||
183 | if (MODIFF <= current_buffer->save_modified) | |
184 | record_first_change (); | |
185 | ||
186 | XSET (lbeg, Lisp_Int, beg); | |
187 | XSET (lend, Lisp_Int, beg + length); | |
188 | entry = Fcons (Qnil, Fcons (prop, Fcons (value, Fcons (lbeg, lend)))); | |
189 | current_buffer->undo_list = Fcons (entry, current_buffer->undo_list); | |
190 | ||
191 | current_buffer = obuf; | |
192 | } | |
193 | ||
c6953be1 JB |
194 | DEFUN ("undo-boundary", Fundo_boundary, Sundo_boundary, 0, 0, 0, |
195 | "Mark a boundary between units of undo.\n\ | |
196 | An undo command will stop at this point,\n\ | |
197 | but another undo command will undo to the previous boundary.") | |
198 | () | |
199 | { | |
200 | Lisp_Object tem; | |
201 | if (EQ (current_buffer->undo_list, Qt)) | |
202 | return Qnil; | |
203 | tem = Fcar (current_buffer->undo_list); | |
265a9e55 | 204 | if (!NILP (tem)) |
c58632fc RS |
205 | { |
206 | /* One way or another, cons nil onto the front of the undo list. */ | |
207 | if (!NILP (pending_boundary)) | |
208 | { | |
209 | /* If we have preallocated the cons cell to use here, | |
210 | use that one. */ | |
211 | XCONS (pending_boundary)->cdr = current_buffer->undo_list; | |
212 | current_buffer->undo_list = pending_boundary; | |
213 | pending_boundary = Qnil; | |
214 | } | |
215 | else | |
216 | current_buffer->undo_list = Fcons (Qnil, current_buffer->undo_list); | |
217 | } | |
c6953be1 JB |
218 | return Qnil; |
219 | } | |
220 | ||
221 | /* At garbage collection time, make an undo list shorter at the end, | |
222 | returning the truncated list. | |
223 | MINSIZE and MAXSIZE are the limits on size allowed, as described below. | |
f06cd136 JB |
224 | In practice, these are the values of undo-limit and |
225 | undo-strong-limit. */ | |
c6953be1 JB |
226 | |
227 | Lisp_Object | |
228 | truncate_undo_list (list, minsize, maxsize) | |
229 | Lisp_Object list; | |
230 | int minsize, maxsize; | |
231 | { | |
232 | Lisp_Object prev, next, last_boundary; | |
233 | int size_so_far = 0; | |
234 | ||
235 | prev = Qnil; | |
236 | next = list; | |
237 | last_boundary = Qnil; | |
238 | ||
239 | /* Always preserve at least the most recent undo record. | |
181a18b1 JB |
240 | If the first element is an undo boundary, skip past it. |
241 | ||
242 | Skip, skip, skip the undo, skip, skip, skip the undo, | |
07627b5d JB |
243 | Skip, skip, skip the undo, skip to the undo bound'ry. |
244 | (Get it? "Skip to my Loo?") */ | |
c6953be1 | 245 | if (XTYPE (next) == Lisp_Cons |
213861c7 | 246 | && NILP (XCONS (next)->car)) |
c6953be1 JB |
247 | { |
248 | /* Add in the space occupied by this element and its chain link. */ | |
249 | size_so_far += sizeof (struct Lisp_Cons); | |
250 | ||
251 | /* Advance to next element. */ | |
252 | prev = next; | |
253 | next = XCONS (next)->cdr; | |
254 | } | |
255 | while (XTYPE (next) == Lisp_Cons | |
213861c7 | 256 | && ! NILP (XCONS (next)->car)) |
c6953be1 JB |
257 | { |
258 | Lisp_Object elt; | |
259 | elt = XCONS (next)->car; | |
260 | ||
261 | /* Add in the space occupied by this element and its chain link. */ | |
262 | size_so_far += sizeof (struct Lisp_Cons); | |
263 | if (XTYPE (elt) == Lisp_Cons) | |
264 | { | |
265 | size_so_far += sizeof (struct Lisp_Cons); | |
266 | if (XTYPE (XCONS (elt)->car) == Lisp_String) | |
267 | size_so_far += (sizeof (struct Lisp_String) - 1 | |
268 | + XSTRING (XCONS (elt)->car)->size); | |
269 | } | |
270 | ||
271 | /* Advance to next element. */ | |
272 | prev = next; | |
273 | next = XCONS (next)->cdr; | |
274 | } | |
275 | if (XTYPE (next) == Lisp_Cons) | |
276 | last_boundary = prev; | |
277 | ||
278 | while (XTYPE (next) == Lisp_Cons) | |
279 | { | |
280 | Lisp_Object elt; | |
281 | elt = XCONS (next)->car; | |
282 | ||
283 | /* When we get to a boundary, decide whether to truncate | |
284 | either before or after it. The lower threshold, MINSIZE, | |
285 | tells us to truncate after it. If its size pushes past | |
286 | the higher threshold MAXSIZE as well, we truncate before it. */ | |
265a9e55 | 287 | if (NILP (elt)) |
c6953be1 JB |
288 | { |
289 | if (size_so_far > maxsize) | |
290 | break; | |
291 | last_boundary = prev; | |
292 | if (size_so_far > minsize) | |
293 | break; | |
294 | } | |
295 | ||
296 | /* Add in the space occupied by this element and its chain link. */ | |
297 | size_so_far += sizeof (struct Lisp_Cons); | |
298 | if (XTYPE (elt) == Lisp_Cons) | |
299 | { | |
300 | size_so_far += sizeof (struct Lisp_Cons); | |
301 | if (XTYPE (XCONS (elt)->car) == Lisp_String) | |
302 | size_so_far += (sizeof (struct Lisp_String) - 1 | |
303 | + XSTRING (XCONS (elt)->car)->size); | |
304 | } | |
305 | ||
306 | /* Advance to next element. */ | |
307 | prev = next; | |
308 | next = XCONS (next)->cdr; | |
309 | } | |
310 | ||
311 | /* If we scanned the whole list, it is short enough; don't change it. */ | |
265a9e55 | 312 | if (NILP (next)) |
c6953be1 JB |
313 | return list; |
314 | ||
315 | /* Truncate at the boundary where we decided to truncate. */ | |
265a9e55 | 316 | if (!NILP (last_boundary)) |
c6953be1 JB |
317 | { |
318 | XCONS (last_boundary)->cdr = Qnil; | |
319 | return list; | |
320 | } | |
321 | else | |
322 | return Qnil; | |
323 | } | |
324 | \f | |
325 | DEFUN ("primitive-undo", Fprimitive_undo, Sprimitive_undo, 2, 2, 0, | |
326 | "Undo N records from the front of the list LIST.\n\ | |
327 | Return what remains of the list.") | |
063fb61f RS |
328 | (n, list) |
329 | Lisp_Object n, list; | |
c6953be1 | 330 | { |
f87a68b3 | 331 | int count = specpdl_ptr - specpdl; |
063fb61f | 332 | register int arg = XINT (n); |
c6953be1 JB |
333 | #if 0 /* This is a good feature, but would make undo-start |
334 | unable to do what is expected. */ | |
335 | Lisp_Object tem; | |
336 | ||
337 | /* If the head of the list is a boundary, it is the boundary | |
338 | preceding this command. Get rid of it and don't count it. */ | |
339 | tem = Fcar (list); | |
265a9e55 | 340 | if (NILP (tem)) |
c6953be1 JB |
341 | list = Fcdr (list); |
342 | #endif | |
343 | ||
f87a68b3 RS |
344 | /* Don't let read-only properties interfere with undo. */ |
345 | if (NILP (current_buffer->read_only)) | |
346 | specbind (Qinhibit_read_only, Qt); | |
347 | ||
c6953be1 JB |
348 | while (arg > 0) |
349 | { | |
350 | while (1) | |
351 | { | |
350bce56 | 352 | Lisp_Object next; |
c6953be1 JB |
353 | next = Fcar (list); |
354 | list = Fcdr (list); | |
350bce56 | 355 | /* Exit inner loop at undo boundary. */ |
265a9e55 | 356 | if (NILP (next)) |
c6953be1 | 357 | break; |
350bce56 RS |
358 | /* Handle an integer by setting point to that value. */ |
359 | if (XTYPE (next) == Lisp_Int) | |
360 | SET_PT (clip_to_bounds (BEGV, XINT (next), ZV)); | |
361 | else if (XTYPE (next) == Lisp_Cons) | |
c6953be1 | 362 | { |
350bce56 RS |
363 | Lisp_Object car, cdr; |
364 | ||
365 | car = Fcar (next); | |
366 | cdr = Fcdr (next); | |
367 | if (EQ (car, Qt)) | |
c6953be1 | 368 | { |
350bce56 RS |
369 | /* Element (t high . low) records previous modtime. */ |
370 | Lisp_Object high, low; | |
371 | int mod_time; | |
372 | ||
373 | high = Fcar (cdr); | |
374 | low = Fcdr (cdr); | |
d8552b2f | 375 | mod_time = (XFASTINT (high) << 16) + XFASTINT (low); |
350bce56 RS |
376 | /* If this records an obsolete save |
377 | (not matching the actual disk file) | |
378 | then don't mark unmodified. */ | |
379 | if (mod_time != current_buffer->modtime) | |
380 | break; | |
e6dd6080 | 381 | #ifdef CLASH_DETECTION |
350bce56 | 382 | Funlock_buffer (); |
e6dd6080 | 383 | #endif /* CLASH_DETECTION */ |
350bce56 | 384 | Fset_buffer_modified_p (Qnil); |
c6953be1 | 385 | } |
d8552b2f RS |
386 | #ifdef USE_TEXT_PROPERTIES |
387 | else if (EQ (car, Qnil)) | |
da9319d5 | 388 | { |
d8552b2f | 389 | /* Element (nil prop val beg . end) is property change. */ |
da9319d5 RS |
390 | Lisp_Object beg, end, prop, val; |
391 | ||
392 | prop = Fcar (cdr); | |
393 | cdr = Fcdr (cdr); | |
394 | val = Fcar (cdr); | |
395 | cdr = Fcdr (cdr); | |
396 | beg = Fcar (cdr); | |
397 | end = Fcdr (cdr); | |
398 | ||
399 | Fput_text_property (beg, end, prop, val, Qnil); | |
400 | } | |
d8552b2f | 401 | #endif /* USE_TEXT_PROPERTIES */ |
350bce56 | 402 | else if (XTYPE (car) == Lisp_Int && XTYPE (cdr) == Lisp_Int) |
c6953be1 | 403 | { |
350bce56 RS |
404 | /* Element (BEG . END) means range was inserted. */ |
405 | Lisp_Object end; | |
406 | ||
407 | if (XINT (car) < BEGV | |
408 | || XINT (cdr) > ZV) | |
c6953be1 | 409 | error ("Changes to be undone are outside visible portion of buffer"); |
f28f04cc RS |
410 | /* Set point first thing, so that undoing this undo |
411 | does not send point back to where it is now. */ | |
350bce56 | 412 | Fgoto_char (car); |
f28f04cc | 413 | Fdelete_region (car, cdr); |
350bce56 RS |
414 | } |
415 | else if (XTYPE (car) == Lisp_String && XTYPE (cdr) == Lisp_Int) | |
416 | { | |
417 | /* Element (STRING . POS) means STRING was deleted. */ | |
418 | Lisp_Object membuf; | |
419 | int pos = XINT (cdr); | |
420 | ||
421 | membuf = car; | |
422 | if (pos < 0) | |
423 | { | |
424 | if (-pos < BEGV || -pos > ZV) | |
425 | error ("Changes to be undone are outside visible portion of buffer"); | |
426 | SET_PT (-pos); | |
427 | Finsert (1, &membuf); | |
428 | } | |
429 | else | |
430 | { | |
431 | if (pos < BEGV || pos > ZV) | |
432 | error ("Changes to be undone are outside visible portion of buffer"); | |
433 | SET_PT (pos); | |
434 | ||
435 | /* Insert before markers so that if the mark is | |
436 | currently on the boundary of this deletion, it | |
437 | ends up on the other side of the now-undeleted | |
438 | text from point. Since undo doesn't even keep | |
439 | track of the mark, this isn't really necessary, | |
440 | but it may lead to better behavior in certain | |
441 | situations. */ | |
442 | Finsert_before_markers (1, &membuf); | |
443 | SET_PT (pos); | |
444 | } | |
c6953be1 JB |
445 | } |
446 | } | |
447 | } | |
448 | arg--; | |
449 | } | |
450 | ||
f87a68b3 | 451 | return unbind_to (count, list); |
c6953be1 JB |
452 | } |
453 | ||
454 | syms_of_undo () | |
455 | { | |
f87a68b3 RS |
456 | Qinhibit_read_only = intern ("inhibit-read-only"); |
457 | staticpro (&Qinhibit_read_only); | |
458 | ||
c58632fc RS |
459 | pending_boundary = Qnil; |
460 | staticpro (&pending_boundary); | |
461 | ||
c6953be1 JB |
462 | defsubr (&Sprimitive_undo); |
463 | defsubr (&Sundo_boundary); | |
464 | } |