428
+ − 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 */
665
+ − 31 extern Charbpos last_point_position;
428
+ − 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);
793
+ − 83 last_undo_buffer = wrap_buffer (b);
428
+ − 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 /* Record an insertion that just happened or is about to happen,
+ − 108 for LENGTH characters at position BEG.
+ − 109 (It is possible to record an insertion before or after the fact
+ − 110 because we don't need to record the contents.) */
+ − 111
+ − 112 void
665
+ − 113 record_insert (struct buffer *b, Charbpos beg, Charcount length)
428
+ − 114 {
+ − 115 if (!undo_prelude (b, 1))
+ − 116 return;
+ − 117
+ − 118 /* If this is following another insertion and consecutive with it
+ − 119 in the buffer, combine the two. */
+ − 120 if (CONSP (b->undo_list))
+ − 121 {
+ − 122 Lisp_Object elt;
+ − 123 elt = XCAR (b->undo_list);
+ − 124 if (CONSP (elt)
+ − 125 && INTP (XCAR (elt))
+ − 126 && INTP (XCDR (elt))
+ − 127 && XINT (XCDR (elt)) == beg)
+ − 128 {
+ − 129 XCDR (elt) = make_int (beg + length);
+ − 130 return;
+ − 131 }
+ − 132 }
+ − 133
+ − 134 b->undo_list = Fcons (Fcons (make_int (beg),
+ − 135 make_int (beg + length)),
+ − 136 b->undo_list);
+ − 137 }
+ − 138
+ − 139 /* Record that a deletion is about to take place,
+ − 140 for LENGTH characters at location BEG. */
+ − 141
+ − 142 void
665
+ − 143 record_delete (struct buffer *b, Charbpos beg, Charcount length)
428
+ − 144 {
+ − 145 /* This function can GC */
+ − 146 Lisp_Object sbeg;
+ − 147 int at_boundary;
+ − 148
+ − 149 if (!undo_prelude (b, 1))
+ − 150 return;
+ − 151
+ − 152 at_boundary = (CONSP (b->undo_list)
+ − 153 && NILP (XCAR (b->undo_list)));
+ − 154
+ − 155 if (BUF_PT (b) == beg + length)
+ − 156 sbeg = make_int (-beg);
+ − 157 else
+ − 158 sbeg = make_int (beg);
+ − 159
+ − 160 /* If we are just after an undo boundary, and
+ − 161 point wasn't at start of deleted range, record where it was. */
+ − 162 if (at_boundary
+ − 163 && BUFFERP (last_point_position_buffer)
+ − 164 && b == XBUFFER (last_point_position_buffer)
+ − 165 && last_point_position != XINT (sbeg))
+ − 166 b->undo_list = Fcons (make_int (last_point_position), b->undo_list);
+ − 167
+ − 168 b->undo_list = Fcons (Fcons (make_string_from_buffer (b, beg,
+ − 169 length),
+ − 170 sbeg),
+ − 171 b->undo_list);
+ − 172 }
+ − 173
+ − 174 /* Record that a replacement is about to take place,
+ − 175 for LENGTH characters at location BEG.
+ − 176 The replacement does not change the number of characters. */
+ − 177
+ − 178 void
665
+ − 179 record_change (struct buffer *b, Charbpos beg, Charcount length)
428
+ − 180 {
+ − 181 record_delete (b, beg, length);
+ − 182 record_insert (b, beg, length);
+ − 183 }
+ − 184
+ − 185 /* Record that an EXTENT is about to be attached or detached in its buffer.
+ − 186 This works much like a deletion or insertion, except that there's no string.
+ − 187 The tricky part is that the buffer we operate on comes from EXTENT.
+ − 188 Most extent changes happen as a side effect of string insertion and
+ − 189 deletion; this call is solely for Fdetach_extent() and Finsert_extent().
+ − 190 */
+ − 191 void
+ − 192 record_extent (Lisp_Object extent, int attached)
+ − 193 {
+ − 194 Lisp_Object obj = Fextent_object (extent);
+ − 195
+ − 196 if (BUFFERP (obj))
+ − 197 {
+ − 198 Lisp_Object token;
+ − 199 struct buffer *b = XBUFFER (obj);
+ − 200 if (!undo_prelude (b, 1))
+ − 201 return;
+ − 202 if (attached)
+ − 203 token = extent;
+ − 204 else
+ − 205 token = list3 (extent, Fextent_start_position (extent),
+ − 206 Fextent_end_position (extent));
+ − 207 b->undo_list = Fcons (token, b->undo_list);
+ − 208 }
+ − 209 else
+ − 210 return;
+ − 211 }
+ − 212
+ − 213 #if 0 /* FSFmacs */
+ − 214 /* Record a change in property PROP (whose old value was VAL)
+ − 215 for LENGTH characters starting at position BEG in BUFFER. */
+ − 216
665
+ − 217 record_property_change (Charbpos beg, Charcount length,
428
+ − 218 Lisp_Object prop, Lisp_Object value,
+ − 219 Lisp_Object buffer)
+ − 220 {
+ − 221 Lisp_Object lbeg, lend, entry;
+ − 222 struct buffer *b = XBUFFER (buffer);
+ − 223
+ − 224 if (!undo_prelude (b, 1))
+ − 225 return;
+ − 226
+ − 227 lbeg = make_int (beg);
+ − 228 lend = make_int (beg + length);
+ − 229 entry = Fcons (Qnil, Fcons (prop, Fcons (value, Fcons (lbeg, lend))));
+ − 230 b->undo_list = Fcons (entry, b->undo_list);
+ − 231 }
+ − 232 #endif /* FSFmacs */
+ − 233
+ − 234
+ − 235 DEFUN ("undo-boundary", Fundo_boundary, 0, 0, 0, /*
+ − 236 Mark a boundary between units of undo.
+ − 237 An undo command will stop at this point,
+ − 238 but another undo command will undo to the previous boundary.
+ − 239 */
+ − 240 ())
+ − 241 {
+ − 242 if (EQ (current_buffer->undo_list, Qt))
+ − 243 return Qnil;
+ − 244 undo_boundary (current_buffer);
+ − 245 return Qnil;
+ − 246 }
+ − 247
+ − 248 /* At garbage collection time, make an undo list shorter at the end,
+ − 249 returning the truncated list.
+ − 250 MINSIZE and MAXSIZE are the limits on size allowed, as described below.
+ − 251 In practice, these are the values of undo-threshold and
+ − 252 undo-high-threshold. */
+ − 253
+ − 254 Lisp_Object
+ − 255 truncate_undo_list (Lisp_Object list, int minsize, int maxsize)
+ − 256 {
+ − 257 Lisp_Object prev, next, last_boundary;
+ − 258 int size_so_far = 0;
+ − 259
+ − 260 if (!(minsize > 0 || maxsize > 0))
+ − 261 return list;
+ − 262
+ − 263 prev = Qnil;
+ − 264 next = list;
+ − 265 last_boundary = Qnil;
+ − 266
+ − 267 if (!CONSP (list))
+ − 268 return (list);
+ − 269
+ − 270 /* Always preserve at least the most recent undo record.
+ − 271 If the first element is an undo boundary, skip past it. */
+ − 272 if (CONSP (next)
+ − 273 && NILP (XCAR (next)))
+ − 274 {
+ − 275 /* Add in the space occupied by this element and its chain link. */
440
+ − 276 size_so_far += sizeof (Lisp_Cons);
428
+ − 277
+ − 278 /* Advance to next element. */
+ − 279 prev = next;
+ − 280 next = XCDR (next);
+ − 281 }
+ − 282 while (CONSP (next)
+ − 283 && !NILP (XCAR (next)))
+ − 284 {
+ − 285 Lisp_Object elt;
+ − 286 elt = XCAR (next);
+ − 287
+ − 288 /* Add in the space occupied by this element and its chain link. */
440
+ − 289 size_so_far += sizeof (Lisp_Cons);
428
+ − 290 if (CONSP (elt))
+ − 291 {
440
+ − 292 size_so_far += sizeof (Lisp_Cons);
428
+ − 293 if (STRINGP (XCAR (elt)))
440
+ − 294 size_so_far += (sizeof (Lisp_String) - 1
428
+ − 295 + XSTRING_LENGTH (XCAR (elt)));
+ − 296 }
+ − 297
+ − 298 /* Advance to next element. */
+ − 299 prev = next;
+ − 300 next = XCDR (next);
+ − 301 }
+ − 302 if (CONSP (next))
+ − 303 last_boundary = prev;
+ − 304
+ − 305 while (CONSP (next))
+ − 306 {
+ − 307 Lisp_Object elt;
+ − 308 elt = XCAR (next);
+ − 309
+ − 310 /* When we get to a boundary, decide whether to truncate
+ − 311 either before or after it. The lower threshold, MINSIZE,
+ − 312 tells us to truncate after it. If its size pushes past
+ − 313 the higher threshold MAXSIZE as well, we truncate before it. */
+ − 314 if (NILP (elt))
+ − 315 {
+ − 316 if (size_so_far > maxsize && maxsize > 0)
+ − 317 break;
+ − 318 last_boundary = prev;
+ − 319 if (size_so_far > minsize && minsize > 0)
+ − 320 break;
+ − 321 }
+ − 322
+ − 323 /* Add in the space occupied by this element and its chain link. */
440
+ − 324 size_so_far += sizeof (Lisp_Cons);
428
+ − 325 if (CONSP (elt))
+ − 326 {
440
+ − 327 size_so_far += sizeof (Lisp_Cons);
428
+ − 328 if (STRINGP (XCAR (elt)))
440
+ − 329 size_so_far += (sizeof (Lisp_String) - 1
428
+ − 330 + XSTRING_LENGTH (XCAR (elt)));
+ − 331 }
+ − 332
+ − 333 /* Advance to next element. */
+ − 334 prev = next;
+ − 335 next = XCDR (next);
+ − 336 }
+ − 337
+ − 338 /* If we scanned the whole list, it is short enough; don't change it. */
+ − 339 if (NILP (next))
+ − 340 return list;
+ − 341
+ − 342 /* Truncate at the boundary where we decided to truncate. */
+ − 343 if (!NILP (last_boundary))
+ − 344 {
+ − 345 XCDR (last_boundary) = Qnil;
+ − 346 return list;
+ − 347 }
+ − 348 else
+ − 349 return Qnil;
+ − 350 }
+ − 351
+ − 352 DEFUN ("primitive-undo", Fprimitive_undo, 2, 2, 0, /*
+ − 353 Undo COUNT records from the front of the list LIST.
+ − 354 Return what remains of the list.
+ − 355 */
+ − 356 (count, list))
+ − 357 {
+ − 358 struct gcpro gcpro1, gcpro2;
+ − 359 Lisp_Object next = Qnil;
+ − 360 /* This function can GC */
+ − 361 int arg;
853
+ − 362 int speccount = internal_bind_int (&inside_undo, 1);
428
+ − 363
+ − 364 #if 0 /* This is a good feature, but would make undo-start
+ − 365 unable to do what is expected. */
+ − 366 Lisp_Object tem;
+ − 367
+ − 368 /* If the head of the list is a boundary, it is the boundary
+ − 369 preceding this command. Get rid of it and don't count it. */
+ − 370 tem = Fcar (list);
+ − 371 if (NILP (tem))
+ − 372 list = Fcdr (list);
+ − 373 #endif
+ − 374
+ − 375 CHECK_INT (count);
+ − 376 arg = XINT (count);
+ − 377 next = Qnil;
+ − 378 GCPRO2 (next, list);
+ − 379
+ − 380 /* Don't let read-only properties interfere with undo. */
+ − 381 if (NILP (current_buffer->read_only))
+ − 382 specbind (Qinhibit_read_only, Qt);
+ − 383
+ − 384 while (arg > 0)
+ − 385 {
+ − 386 while (1)
+ − 387 {
+ − 388 if (NILP (list))
+ − 389 break;
+ − 390 else if (!CONSP (list))
+ − 391 goto rotten;
+ − 392 next = XCAR (list);
+ − 393 list = XCDR (list);
+ − 394 /* Exit inner loop at undo boundary. */
+ − 395 if (NILP (next))
+ − 396 break;
+ − 397 /* Handle an integer by setting point to that value. */
+ − 398 else if (INTP (next))
+ − 399 BUF_SET_PT (current_buffer,
665
+ − 400 charbpos_clip_to_bounds (BUF_BEGV (current_buffer),
428
+ − 401 XINT (next),
+ − 402 BUF_ZV (current_buffer)));
+ − 403 else if (CONSP (next))
+ − 404 {
+ − 405 Lisp_Object car = XCAR (next);
+ − 406 Lisp_Object cdr = XCDR (next);
+ − 407
+ − 408 if (EQ (car, Qt))
+ − 409 {
+ − 410 /* Element (t high . low) records previous modtime. */
+ − 411 Lisp_Object high, low;
+ − 412 int mod_time;
+ − 413 if (!CONSP (cdr)) goto rotten;
+ − 414 high = XCAR (cdr);
+ − 415 low = XCDR (cdr);
+ − 416 if (!INTP (high) || !INTP (low)) goto rotten;
+ − 417 mod_time = (XINT (high) << 16) + XINT (low);
+ − 418 /* If this records an obsolete save
+ − 419 (not matching the actual disk file)
+ − 420 then don't mark unmodified. */
+ − 421 if (mod_time != current_buffer->modtime)
+ − 422 break;
+ − 423 #ifdef CLASH_DETECTION
+ − 424 Funlock_buffer ();
+ − 425 #endif /* CLASH_DETECTION */
2297
+ − 426 /* #### need to check if this can GC */
428
+ − 427 Fset_buffer_modified_p (Qnil, Qnil);
+ − 428 }
+ − 429 else if (EXTENTP (car))
+ − 430 {
+ − 431 /* Element (extent start end) means that EXTENT was
+ − 432 detached, and we need to reattach it. */
+ − 433 Lisp_Object extent_obj, start, end;
+ − 434
+ − 435 extent_obj = car;
+ − 436 start = Fcar (cdr);
+ − 437 end = Fcar (Fcdr (cdr));
+ − 438
+ − 439 if (!INTP (start) || !INTP (end))
+ − 440 goto rotten;
+ − 441 Fset_extent_endpoints (extent_obj, start, end,
+ − 442 Fcurrent_buffer ());
+ − 443 }
+ − 444 #if 0 /* FSFmacs */
+ − 445 else if (EQ (car, Qnil))
+ − 446 {
+ − 447 /* Element (nil prop val beg . end) is property change. */
+ − 448 Lisp_Object beg, end, prop, val;
+ − 449
+ − 450 prop = Fcar (cdr);
+ − 451 cdr = Fcdr (cdr);
+ − 452 val = Fcar (cdr);
+ − 453 cdr = Fcdr (cdr);
+ − 454 beg = Fcar (cdr);
+ − 455 end = Fcdr (cdr);
+ − 456
+ − 457 Fput_text_property (beg, end, prop, val, Qnil);
+ − 458 }
+ − 459 #endif /* FSFmacs */
+ − 460 else if (INTP (car) && INTP (cdr))
+ − 461 {
+ − 462 /* Element (BEG . END) means range was inserted. */
+ − 463
+ − 464 if (XINT (car) < BUF_BEGV (current_buffer)
+ − 465 || XINT (cdr) > BUF_ZV (current_buffer))
563
+ − 466 signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound);
428
+ − 467 /* Set point first thing, so that undoing this undo
+ − 468 does not send point back to where it is now. */
+ − 469 Fgoto_char (car, Qnil);
+ − 470 Fdelete_region (car, cdr, Qnil);
+ − 471 }
+ − 472 else if (STRINGP (car) && INTP (cdr))
+ − 473 {
+ − 474 /* Element (STRING . POS) means STRING was deleted. */
+ − 475 Lisp_Object membuf = car;
+ − 476 int pos = XINT (cdr);
+ − 477
+ − 478 if (pos < 0)
+ − 479 {
+ − 480 if (-pos < BUF_BEGV (current_buffer) || -pos > BUF_ZV (current_buffer))
563
+ − 481 signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound);
428
+ − 482 BUF_SET_PT (current_buffer, -pos);
+ − 483 Finsert (1, &membuf);
+ − 484 }
+ − 485 else
+ − 486 {
+ − 487 if (pos < BUF_BEGV (current_buffer) || pos > BUF_ZV (current_buffer))
563
+ − 488 signal_error (Qinvalid_operation, "Changes to be undone are outside visible portion of buffer", Qunbound);
428
+ − 489 BUF_SET_PT (current_buffer, pos);
+ − 490
+ − 491 /* Insert before markers so that if the mark is
+ − 492 currently on the boundary of this deletion, it
+ − 493 ends up on the other side of the now-undeleted
+ − 494 text from point. Since undo doesn't even keep
+ − 495 track of the mark, this isn't really necessary,
+ − 496 but it may lead to better behavior in certain
+ − 497 situations.
+ − 498
+ − 499 I'm doubtful that this is safe; you could mess
+ − 500 up the process-output mark in shell buffers, so
+ − 501 until I hear a compelling reason for this change,
+ − 502 I'm leaving it out. -jwz
+ − 503 */
+ − 504 /* Finsert_before_markers (1, &membuf); */
+ − 505 Finsert (1, &membuf);
+ − 506 BUF_SET_PT (current_buffer, pos);
+ − 507 }
+ − 508 }
+ − 509 else
+ − 510 {
+ − 511 goto rotten;
+ − 512 }
+ − 513 }
+ − 514 else if (EXTENTP (next))
+ − 515 Fdetach_extent (next);
+ − 516 else
+ − 517 {
+ − 518 rotten:
563
+ − 519 signal_continuable_error
+ − 520 (Qinvalid_state,
+ − 521 "Something rotten in the state of undo", next);
428
+ − 522 }
+ − 523 }
+ − 524 arg--;
+ − 525 }
+ − 526
+ − 527 UNGCPRO;
771
+ − 528 return unbind_to_1 (speccount, list);
428
+ − 529 }
+ − 530
+ − 531 void
+ − 532 syms_of_undo (void)
+ − 533 {
+ − 534 DEFSUBR (Fprimitive_undo);
+ − 535 DEFSUBR (Fundo_boundary);
563
+ − 536 DEFSYMBOL (Qinhibit_read_only);
428
+ − 537 }
+ − 538
+ − 539 void
+ − 540 reinit_vars_of_undo (void)
+ − 541 {
+ − 542 inside_undo = 0;
+ − 543 }
+ − 544
+ − 545 void
+ − 546 vars_of_undo (void)
+ − 547 {
+ − 548 pending_boundary = Qnil;
+ − 549 staticpro (&pending_boundary);
+ − 550 last_undo_buffer = Qnil;
+ − 551 staticpro (&last_undo_buffer);
+ − 552 }