editfns.c 172 KB
Newer Older
1
/* Lisp functions pertaining to editing.                 -*- coding: utf-8 -*-
2

Paul Eggert's avatar
Paul Eggert committed
3
Copyright (C) 1985-1987, 1989, 1993-2018 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
4 5 6

This file is part of GNU Emacs.

7
GNU Emacs is free software: you can redistribute it and/or modify
Jim Blandy's avatar
Jim Blandy committed
8
it under the terms of the GNU General Public License as published by
9 10
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
Jim Blandy's avatar
Jim Blandy committed
11 12 13 14 15 16 17

GNU Emacs 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
18
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
Jim Blandy's avatar
Jim Blandy committed
19 20


21
#include <config.h>
22
#include <sys/types.h>
23
#include <stdio.h>
Jim Blandy's avatar
Jim Blandy committed
24

25
#ifdef HAVE_PWD_H
Jim Blandy's avatar
Jim Blandy committed
26
#include <pwd.h>
27
#include <grp.h>
Jim Blandy's avatar
Jim Blandy committed
28 29
#endif

Andreas Schwab's avatar
Andreas Schwab committed
30 31
#include <unistd.h>

32 33 34 35
#ifdef HAVE_SYS_UTSNAME_H
#include <sys/utsname.h>
#endif

36 37
#include "lisp.h"

38 39 40 41
/* systime.h includes <sys/time.h> which, on some systems, is required
   for <sys/resource.h>; thus systime.h must be included before
   <sys/resource.h> */
#include "systime.h"
42 43

#if defined HAVE_SYS_RESOURCE_H
44
#include <sys/resource.h>
45 46
#endif

47
#include <errno.h>
48
#include <float.h>
49
#include <limits.h>
50

51
#include <c-ctype.h>
52
#include <intprops.h>
Paul Eggert's avatar
Paul Eggert committed
53
#include <stdlib.h>
Paul Eggert's avatar
Paul Eggert committed
54
#include <strftime.h>
55
#include <verify.h>
56

57
#include "composite.h"
58
#include "intervals.h"
59
#include "ptr-bounds.h"
60
#include "character.h"
61
#include "buffer.h"
62
#include "coding.h"
Jim Blandy's avatar
Jim Blandy committed
63
#include "window.h"
YAMAMOTO Mitsuharu's avatar
YAMAMOTO Mitsuharu committed
64
#include "blockinput.h"
Jim Blandy's avatar
Jim Blandy committed
65

66 67
#define TM_YEAR_BASE 1900

68
#ifdef WINDOWSNT
69
extern Lisp_Object w32_get_internal_run_time (void);
70 71
#endif

72
static struct lisp_time lisp_time_struct (Lisp_Object, int *);
73
static Lisp_Object format_time_string (char const *, ptrdiff_t, struct timespec,
74
				       Lisp_Object, struct tm *);
75
static long int tm_gmtoff (struct tm *);
76
static int tm_diff (struct tm *, struct tm *);
77
static void update_buffer_properties (ptrdiff_t, ptrdiff_t);
78
static Lisp_Object styled_format (ptrdiff_t, Lisp_Object *, bool);
79

80 81 82 83
#ifndef HAVE_TM_GMTOFF
# define HAVE_TM_GMTOFF false
#endif

84 85
enum { tzeqlen = sizeof "TZ=" - 1 };

Paul Eggert's avatar
Paul Eggert committed
86
/* Time zones equivalent to current local time and to UTC, respectively.  */
87 88
static timezone_t local_tz;
static timezone_t const utc_tz = 0;
89

90 91 92 93 94 95 96 97 98 99 100
/* The cached value of Vsystem_name.  This is used only to compare it
   to Vsystem_name, so it need not be visible to the GC.  */
static Lisp_Object cached_system_name;

static void
init_and_cache_system_name (void)
{
  init_system_name ();
  cached_system_name = Vsystem_name;
}

101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119
static struct tm *
emacs_localtime_rz (timezone_t tz, time_t const *t, struct tm *tm)
{
  tm = localtime_rz (tz, t, tm);
  if (!tm && errno == ENOMEM)
    memory_full (SIZE_MAX);
  return tm;
}

static time_t
emacs_mktime_z (timezone_t tz, struct tm *tm)
{
  errno = 0;
  time_t t = mktime_z (tz, tm);
  if (t == (time_t) -1 && errno == ENOMEM)
    memory_full (SIZE_MAX);
  return t;
}

Paul Eggert's avatar
Paul Eggert committed
120 121
static _Noreturn void
invalid_time_zone_specification (Lisp_Object zone)
122
{
Paul Eggert's avatar
Paul Eggert committed
123
  xsignal2 (Qerror, build_string ("Invalid time zone specification"), zone);
124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141
}

/* Free a timezone, except do not free the time zone for local time.
   Freeing utc_tz is also a no-op.  */
static void
xtzfree (timezone_t tz)
{
  if (tz != local_tz)
    tzfree (tz);
}

/* Convert the Lisp time zone rule ZONE to a timezone_t object.
   The returned value either is 0, or is LOCAL_TZ, or is newly allocated.
   If SETTZ, set Emacs local time to the time zone rule; otherwise,
   the caller should eventually pass the returned value to xtzfree.  */
static timezone_t
tzlookup (Lisp_Object zone, bool settz)
{
Paul Eggert's avatar
Paul Eggert committed
142 143 144
  static char const tzbuf_format[] = "<%+.*"pI"d>%s%"pI"d:%02d:%02d";
  char const *trailing_tzbuf_format = tzbuf_format + sizeof "<%+.*"pI"d" - 1;
  char tzbuf[sizeof tzbuf_format + 2 * INT_STRLEN_BOUND (EMACS_INT)];
145 146 147 148 149
  char const *zone_string;
  timezone_t new_tz;

  if (NILP (zone))
    return local_tz;
Paul Eggert's avatar
Paul Eggert committed
150
  else if (EQ (zone, Qt) || EQ (zone, make_number (0)))
151 152 153 154 155 156
    {
      zone_string = "UTC0";
      new_tz = utc_tz;
    }
  else
    {
157 158
      bool plain_integer = INTEGERP (zone);

159 160 161
      if (EQ (zone, Qwall))
	zone_string = 0;
      else if (STRINGP (zone))
162 163 164
	zone_string = SSDATA (ENCODE_SYSTEM (zone));
      else if (plain_integer || (CONSP (zone) && INTEGERP (XCAR (zone))
				 && CONSP (XCDR (zone))))
165
	{
166 167 168 169 170 171 172
	  Lisp_Object abbr;
	  if (!plain_integer)
	    {
	      abbr = XCAR (XCDR (zone));
	      zone = XCAR (zone);
	    }

173
	  EMACS_INT abszone = eabs (XINT (zone)), hour = abszone / (60 * 60);
174 175 176 177 178 179 180 181 182 183 184 185 186
	  int hour_remainder = abszone % (60 * 60);
	  int min = hour_remainder / 60, sec = hour_remainder % 60;

	  if (plain_integer)
	    {
	      int prec = 2;
	      EMACS_INT numzone = hour;
	      if (hour_remainder != 0)
		{
		  prec += 2, numzone = 100 * numzone + min;
		  if (sec != 0)
		    prec += 2, numzone = 100 * numzone + sec;
		}
187 188
	      sprintf (tzbuf, tzbuf_format, prec,
		       XINT (zone) < 0 ? -numzone : numzone,
189 190 191 192 193 194 195 196 197 198 199 200 201
		       &"-"[XINT (zone) < 0], hour, min, sec);
	      zone_string = tzbuf;
	    }
	  else
	    {
	      AUTO_STRING (leading, "<");
	      AUTO_STRING_WITH_LEN (trailing, tzbuf,
				    sprintf (tzbuf, trailing_tzbuf_format,
					     &"-"[XINT (zone) < 0],
					     hour, min, sec));
	      zone_string = SSDATA (concat3 (leading, ENCODE_SYSTEM (abbr),
					     trailing));
	    }
202 203
	}
      else
Paul Eggert's avatar
Paul Eggert committed
204 205 206
	invalid_time_zone_specification (zone);

      new_tz = tzalloc (zone_string);
Paul Eggert's avatar
Paul Eggert committed
207 208 209 210 211 212 213 214 215 216 217 218

#if defined __NetBSD_Version__ && __NetBSD_Version__ < 700000000
      /* NetBSD 6 tzalloc mishandles POSIX TZ strings (Bug#30738).
	 If possible, fall back on tzdb.  */
      if (!new_tz && errno != ENOMEM && plain_integer
	  && XINT (zone) % (60 * 60) == 0)
	{
	  sprintf (tzbuf, "Etc/GMT%+"pI"d", - (XINT (zone) / (60 * 60)));
	  new_tz = tzalloc (zone_string);
	}
#endif

Paul Eggert's avatar
Paul Eggert committed
219 220 221 222 223 224
      if (!new_tz)
	{
	  if (errno == ENOMEM)
	    memory_full (SIZE_MAX);
	  invalid_time_zone_specification (zone);
	}
225 226 227 228 229 230
    }

  if (settz)
    {
      block_input ();
      emacs_setenv_TZ (zone_string);
Paul Eggert's avatar
Paul Eggert committed
231
      tzset ();
232 233 234 235 236 237 238 239 240
      timezone_t old_tz = local_tz;
      local_tz = new_tz;
      tzfree (old_tz);
      unblock_input ();
    }

  return new_tz;
}

Jim Blandy's avatar
Jim Blandy committed
241
void
242
init_editfns (bool dumping)
Jim Blandy's avatar
Jim Blandy committed
243
{
Paul Eggert's avatar
Paul Eggert committed
244
#if !defined CANNOT_DUMP
245 246 247 248 249
  /* A valid but unlikely setting for the TZ environment variable.
     It is OK (though a bit slower) if the user chooses this value.  */
  static char dump_tz_string[] = "TZ=UtC0";
#endif

250
  const char *user_name;
251
  register char *p;
Jim Blandy's avatar
Jim Blandy committed
252 253 254 255
  struct passwd *pw;	/* password entry for the current user */
  Lisp_Object tem;

  /* Set up system_name even when dumping.  */
256
  init_and_cache_system_name ();
Jim Blandy's avatar
Jim Blandy committed
257 258

#ifndef CANNOT_DUMP
259 260
  /* When just dumping out, set the time zone to a known unlikely value
     and skip the rest of this function.  */
261
  if (dumping)
262
    {
263
      xputenv (dump_tz_string);
264 265 266 267 268 269
      tzset ();
      return;
    }
#endif

  char *tz = getenv ("TZ");
Jim Blandy's avatar
Jim Blandy committed
270

Paul Eggert's avatar
Paul Eggert committed
271
#if !defined CANNOT_DUMP
272 273 274 275 276
  /* If the execution TZ happens to be the same as the dump TZ,
     change it to some other value and then change it back,
     to force the underlying implementation to reload the TZ info.
     This is needed on implementations that load TZ info from files,
     since the TZ file contents may differ between dump and execution.  */
277
  if (tz && strcmp (tz, &dump_tz_string[tzeqlen]) == 0)
278 279 280 281 282 283 284
    {
      ++*tz;
      tzset ();
      --*tz;
    }
#endif

285
  /* Set the time zone rule now, so that the call to putenv is done
286
     before multiple threads are active.  */
287
  tzlookup (tz ? build_string (tz) : Qwall, true);
288

289
  pw = getpwuid (getuid ());
Morten Welinder's avatar
Morten Welinder committed
290 291
#ifdef MSDOS
  /* We let the real user name default to "root" because that's quite
292
     accurate on MS-DOS and because it lets Emacs find the init file.
Morten Welinder's avatar
Morten Welinder committed
293
     (The DVX libraries override the Djgpp libraries here.)  */
294
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "root");
Morten Welinder's avatar
Morten Welinder committed
295
#else
296
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "unknown");
Morten Welinder's avatar
Morten Welinder committed
297
#endif
Jim Blandy's avatar
Jim Blandy committed
298

Jim Blandy's avatar
Jim Blandy committed
299 300
  /* Get the effective user name, by consulting environment variables,
     or the effective uid if those are unset.  */
301
  user_name = getenv ("LOGNAME");
Jim Blandy's avatar
Jim Blandy committed
302
  if (!user_name)
303
#ifdef WINDOWSNT
304
    user_name = getenv ("USERNAME");	/* it's USERNAME on NT */
305
#else  /* WINDOWSNT */
306
    user_name = getenv ("USER");
307
#endif /* WINDOWSNT */
Jim Blandy's avatar
Jim Blandy committed
308 309
  if (!user_name)
    {
310 311
      pw = getpwuid (geteuid ());
      user_name = pw ? pw->pw_name : "unknown";
Jim Blandy's avatar
Jim Blandy committed
312
    }
313
  Vuser_login_name = build_string (user_name);
Jim Blandy's avatar
Jim Blandy committed
314

Jim Blandy's avatar
Jim Blandy committed
315 316
  /* If the user name claimed in the environment vars differs from
     the real uid, use the claimed name to find the full name.  */
317
  tem = Fstring_equal (Vuser_login_name, Vuser_real_login_name);
318 319 320 321 322 323 324 325
  if (! NILP (tem))
    tem = Vuser_login_name;
  else
    {
      uid_t euid = geteuid ();
      tem = make_fixnum_or_float (euid);
    }
  Vuser_full_name = Fuser_full_name (tem);
Sam Steingold's avatar
Sam Steingold committed
326

327
  p = getenv ("NAME");
328 329
  if (p)
    Vuser_full_name = build_string (p);
330 331
  else if (NILP (Vuser_full_name))
    Vuser_full_name = build_string ("unknown");
332 333 334 335 336 337 338 339 340 341

#ifdef HAVE_SYS_UTSNAME_H
  {
    struct utsname uts;
    uname (&uts);
    Voperating_system_release = build_string (uts.release);
  }
#else
  Voperating_system_release = Qnil;
#endif
Jim Blandy's avatar
Jim Blandy committed
342 343
}

Paul Eggert's avatar
Paul Eggert committed
344
DEFUN ("char-to-string", Fchar_to_string, Schar_to_string, 1, 1, 0,
345 346
       doc: /* Convert arg CHAR to a string containing that character.
usage: (char-to-string CHAR)  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
347
  (Lisp_Object character)
Jim Blandy's avatar
Jim Blandy committed
348
{
349
  int c, len;
350
  unsigned char str[MAX_MULTIBYTE_LENGTH];
Karl Heuer's avatar
Karl Heuer committed
351

352
  CHECK_CHARACTER (character);
353
  c = XFASTINT (character);
Jim Blandy's avatar
Jim Blandy committed
354

355
  len = CHAR_STRING (c, str);
356
  return make_string_from_bytes ((char *) str, 1, len);
Jim Blandy's avatar
Jim Blandy committed
357 358
}

359
DEFUN ("byte-to-string", Fbyte_to_string, Sbyte_to_string, 1, 1, 0,
360
       doc: /* Convert arg BYTE to a unibyte string containing that byte.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
361
  (Lisp_Object byte)
362
{
363
  unsigned char b;
364
  CHECK_NUMBER (byte);
365 366
  if (XINT (byte) < 0 || XINT (byte) > 255)
    error ("Invalid byte");
367
  b = XINT (byte);
368
  return make_string_from_bytes ((char *) &b, 1, 1);
369 370
}

Jim Blandy's avatar
Jim Blandy committed
371
DEFUN ("string-to-char", Fstring_to_char, Sstring_to_char, 1, 1, 0,
372
       doc: /* Return the first character in STRING.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
373
  (register Lisp_Object string)
Jim Blandy's avatar
Jim Blandy committed
374 375
{
  register Lisp_Object val;
376
  CHECK_STRING (string);
377
  if (SCHARS (string))
378 379
    {
      if (STRING_MULTIBYTE (string))
380
	XSETFASTINT (val, STRING_CHAR (SDATA (string)));
381
      else
382
	XSETFASTINT (val, SREF (string, 0));
383
    }
Jim Blandy's avatar
Jim Blandy committed
384
  else
385
    XSETFASTINT (val, 0);
Jim Blandy's avatar
Jim Blandy committed
386 387 388
  return val;
}

Paul Eggert's avatar
Paul Eggert committed
389
DEFUN ("point", Fpoint, Spoint, 0, 0, 0,
390 391
       doc: /* Return value of point, as an integer.
Beginning of buffer is position (point-min).  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
392
  (void)
Jim Blandy's avatar
Jim Blandy committed
393 394
{
  Lisp_Object temp;
395
  XSETFASTINT (temp, PT);
Jim Blandy's avatar
Jim Blandy committed
396 397 398
  return temp;
}

Paul Eggert's avatar
Paul Eggert committed
399
DEFUN ("point-marker", Fpoint_marker, Spoint_marker, 0, 0, 0,
400
       doc: /* Return value of point, as a marker object.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
401
  (void)
Jim Blandy's avatar
Jim Blandy committed
402
{
403
  return build_marker (current_buffer, PT, PT_BYTE);
Jim Blandy's avatar
Jim Blandy committed
404 405
}

Paul Eggert's avatar
Paul Eggert committed
406
DEFUN ("goto-char", Fgoto_char, Sgoto_char, 1, 1, "NGoto char: ",
407
       doc: /* Set point to POSITION, a number or marker.
Eli Zaretskii's avatar
Eli Zaretskii committed
408 409 410
Beginning of buffer is position (point-min), end is (point-max).

The return value is POSITION.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
411
  (register Lisp_Object position)
Jim Blandy's avatar
Jim Blandy committed
412
{
413 414 415 416 417 418
  if (MARKERP (position))
    set_point_from_marker (position);
  else if (INTEGERP (position))
    SET_PT (clip_to_bounds (BEGV, XINT (position), ZV));
  else
    wrong_type_argument (Qinteger_or_marker_p, position);
419
  return position;
Jim Blandy's avatar
Jim Blandy committed
420 421
}

422 423

/* Return the start or end position of the region.
424
   BEGINNINGP means return the start.
425 426
   If there is no region active, signal an error. */

Jim Blandy's avatar
Jim Blandy committed
427
static Lisp_Object
428
region_limit (bool beginningp)
Jim Blandy's avatar
Jim Blandy committed
429
{
430
  Lisp_Object m;
431

432 433
  if (!NILP (Vtransient_mark_mode)
      && NILP (Vmark_even_if_inactive)
Tom Tromey's avatar
Tom Tromey committed
434
      && NILP (BVAR (current_buffer, mark_active)))
435
    xsignal0 (Qmark_inactive);
436

Tom Tromey's avatar
Tom Tromey committed
437
  m = Fmarker_position (BVAR (current_buffer, mark));
438
  if (NILP (m))
439
    error ("The mark is not set now, so there is no region");
440

441
  /* Clip to the current narrowing (bug#11770).  */
442
  return make_number ((PT < XFASTINT (m)) == beginningp
443 444
		      ? PT
		      : clip_to_bounds (BEGV, XFASTINT (m), ZV));
Jim Blandy's avatar
Jim Blandy committed
445 446 447
}

DEFUN ("region-beginning", Fregion_beginning, Sregion_beginning, 0, 0, 0,
448
       doc: /* Return the integer value of point or mark, whichever is smaller.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
449
  (void)
Jim Blandy's avatar
Jim Blandy committed
450
{
451
  return region_limit (1);
Jim Blandy's avatar
Jim Blandy committed
452 453 454
}

DEFUN ("region-end", Fregion_end, Sregion_end, 0, 0, 0,
455
       doc: /* Return the integer value of point or mark, whichever is larger.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
456
  (void)
Jim Blandy's avatar
Jim Blandy committed
457
{
458
  return region_limit (0);
Jim Blandy's avatar
Jim Blandy committed
459 460 461
}

DEFUN ("mark-marker", Fmark_marker, Smark_marker, 0, 0, 0,
462
       doc: /* Return this buffer's mark, as a marker object.
Pavel Janík's avatar
Pavel Janík committed
463
Watch out!  Moving this marker changes the mark position.
464
If you set the marker not to point anywhere, the buffer will have no mark.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
465
  (void)
Jim Blandy's avatar
Jim Blandy committed
466
{
Tom Tromey's avatar
Tom Tromey committed
467
  return BVAR (current_buffer, mark);
Jim Blandy's avatar
Jim Blandy committed
468
}
469 470


471 472 473 474
/* Find all the overlays in the current buffer that touch position POS.
   Return the number found, and store them in a vector in VEC
   of length LEN.  */

475 476
static ptrdiff_t
overlays_around (EMACS_INT pos, Lisp_Object *vec, ptrdiff_t len)
477
{
478 479
  Lisp_Object overlay, start, end;
  struct Lisp_Overlay *tail;
480
  ptrdiff_t startpos, endpos;
481
  ptrdiff_t idx = 0;
482

483
  for (tail = current_buffer->overlays_before; tail; tail = tail->next)
484
    {
485
      XSETMISC (overlay, tail);
486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501

      end = OVERLAY_END (overlay);
      endpos = OVERLAY_POSITION (end);
      if (endpos < pos)
	  break;
      start = OVERLAY_START (overlay);
      startpos = OVERLAY_POSITION (start);
      if (startpos <= pos)
	{
	  if (idx < len)
	    vec[idx] = overlay;
	  /* Keep counting overlays even if we can't return them all.  */
	  idx++;
	}
    }

502
  for (tail = current_buffer->overlays_after; tail; tail = tail->next)
503
    {
504
      XSETMISC (overlay, tail);
505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522

      start = OVERLAY_START (overlay);
      startpos = OVERLAY_POSITION (start);
      if (pos < startpos)
	break;
      end = OVERLAY_END (overlay);
      endpos = OVERLAY_POSITION (end);
      if (pos <= endpos)
	{
	  if (idx < len)
	    vec[idx] = overlay;
	  idx++;
	}
    }

  return idx;
}

523 524 525 526 527 528 529 530 531
DEFUN ("get-pos-property", Fget_pos_property, Sget_pos_property, 2, 3, 0,
       doc: /* Return the value of POSITION's property PROP, in OBJECT.
Almost identical to `get-char-property' except for the following difference:
Whereas `get-char-property' returns the property of the char at (i.e. right
after) POSITION, this pays attention to properties's stickiness and overlays's
advancement settings, in order to find the property of POSITION itself,
i.e. the property that a char would inherit if it were inserted
at POSITION.  */)
  (Lisp_Object position, register Lisp_Object prop, Lisp_Object object)
532 533 534 535 536
{
  CHECK_NUMBER_COERCE_MARKER (position);

  if (NILP (object))
    XSETBUFFER (object, current_buffer);
537
  else if (WINDOWP (object))
538
    object = XWINDOW (object)->contents;
539 540 541 542 543 544 545

  if (!BUFFERP (object))
    /* pos-property only makes sense in buffers right now, since strings
       have no overlays and no notion of insertion for which stickiness
       could be obeyed.  */
    return Fget_text_property (position, prop, object);
  else
546
    {
547
      EMACS_INT posn = XINT (position);
548
      ptrdiff_t noverlays;
549 550
      Lisp_Object *overlay_vec, tem;
      struct buffer *obuf = current_buffer;
551
      USE_SAFE_ALLOCA;
552 553 554 555

      set_buffer_temp (XBUFFER (object));

      /* First try with room for 40 overlays.  */
556 557 558
      Lisp_Object overlay_vecbuf[40];
      noverlays = ARRAYELTS (overlay_vecbuf);
      overlay_vec = overlay_vecbuf;
559 560 561 562
      noverlays = overlays_around (posn, overlay_vec, noverlays);

      /* If there are more than 40,
	 make enough space for all, and try again.  */
563
      if (ARRAYELTS (overlay_vecbuf) < noverlays)
564
	{
565
	  SAFE_ALLOCA_LISP (overlay_vec, noverlays);
566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587
	  noverlays = overlays_around (posn, overlay_vec, noverlays);
	}
      noverlays = sort_overlays (overlay_vec, noverlays, NULL);

      set_buffer_temp (obuf);

      /* Now check the overlays in order of decreasing priority.  */
      while (--noverlays >= 0)
	{
	  Lisp_Object ol = overlay_vec[noverlays];
	  tem = Foverlay_get (ol, prop);
	  if (!NILP (tem))
	    {
	      /* Check the overlay is indeed active at point.  */
	      Lisp_Object start = OVERLAY_START (ol), finish = OVERLAY_END (ol);
	      if ((OVERLAY_POSITION (start) == posn
		   && XMARKER (start)->insertion_type == 1)
		  || (OVERLAY_POSITION (finish) == posn
		      && XMARKER (finish)->insertion_type == 0))
		; /* The overlay will not cover a char inserted at point.  */
	      else
		{
588
		  SAFE_FREE ();
589 590 591 592
		  return tem;
		}
	    }
	}
593
      SAFE_FREE ();
594

595
      { /* Now check the text properties.  */
596 597 598 599 600 601 602 603 604 605
	int stickiness = text_property_stickiness (prop, position, object);
	if (stickiness > 0)
	  return Fget_text_property (position, prop, object);
	else if (stickiness < 0
		 && XINT (position) > BUF_BEGV (XBUFFER (object)))
	  return Fget_text_property (make_number (XINT (position) - 1),
				     prop, object);
	else
	  return Qnil;
      }
606 607 608
    }
}

609
/* Find the field surrounding POS in *BEG and *END.  If POS is nil,
Lars Hansen's avatar
Lars Hansen committed
610
   the value of point is used instead.  If BEG or END is null,
611
   means don't store the beginning or end of the field.
612

613 614 615
   BEG_LIMIT and END_LIMIT serve to limit the ranged of the returned
   results; they do not effect boundary behavior.

616
   If MERGE_AT_BOUNDARY is non-nil, then if POS is at the very first
617 618 619 620
   position of a field, then the beginning of the previous field is
   returned instead of the beginning of POS's field (since the end of a
   field is actually also the beginning of the next input field, this
   behavior is sometimes useful).  Additionally in the MERGE_AT_BOUNDARY
621
   non-nil case, if two fields are separated by a field with the special
622 623 624
   value `boundary', and POS lies within it, then the two separated
   fields are considered to be adjacent, and POS between them, when
   finding the beginning and ending of the "merged" field.
625 626 627 628

   Either BEG or END may be 0, in which case the corresponding value
   is not stored.  */

629
static void
630 631
find_field (Lisp_Object pos, Lisp_Object merge_at_boundary,
	    Lisp_Object beg_limit,
632
	    ptrdiff_t *beg, Lisp_Object end_limit, ptrdiff_t *end)
633
{
634 635
  /* Fields right before and after the point.  */
  Lisp_Object before_field, after_field;
636 637 638 639
  /* True if POS counts as the start of a field.  */
  bool at_field_start = 0;
  /* True if POS counts as the end of a field.  */
  bool at_field_end = 0;
640

641 642 643
  if (NILP (pos))
    XSETFASTINT (pos, PT);
  else
644
    CHECK_NUMBER_COERCE_MARKER (pos);
645

646
  after_field
647
    = get_char_property_and_overlay (pos, Qfield, Qnil, NULL);
648 649
  before_field
    = (XFASTINT (pos) > BEGV
Miles Bader's avatar
Miles Bader committed
650
       ? get_char_property_and_overlay (make_number (XINT (pos) - 1),
651
					Qfield, Qnil, NULL)
652 653 654
       /* Using nil here would be a more obvious choice, but it would
          fail when the buffer starts with a non-sticky field.  */
       : after_field);
655 656 657 658 659 660 661

  /* See if we need to handle the case where MERGE_AT_BOUNDARY is nil
     and POS is at beginning of a field, which can also be interpreted
     as the end of the previous field.  Note that the case where if
     MERGE_AT_BOUNDARY is non-nil (see function comment) is actually the
     more natural one; then we avoid treating the beginning of a field
     specially.  */
662
  if (NILP (merge_at_boundary))
663
    {
664
      Lisp_Object field = Fget_pos_property (pos, Qfield, Qnil);
665
      if (!EQ (field, after_field))
666
	at_field_end = 1;
667 668
      if (!EQ (field, before_field))
	at_field_start = 1;
669 670 671 672 673 674
      if (NILP (field) && at_field_start && at_field_end)
	/* If an inserted char would have a nil field while the surrounding
	   text is non-nil, we're probably not looking at a
	   zero-length field, but instead at a non-nil field that's
	   not intended for editing (such as comint's prompts).  */
	at_field_end = at_field_start = 0;
675 676
    }

677 678 679 680 681 682
  /* Note about special `boundary' fields:

     Consider the case where the point (`.') is between the fields `x' and `y':

	xxxx.yyyy

683
     In this situation, if merge_at_boundary is non-nil, consider the
684 685 686 687
     `x' and `y' fields as forming one big merged field, and so the end
     of the field is the end of `y'.

     However, if `x' and `y' are separated by a special `boundary' field
688
     (a field with a `field' char-property of 'boundary), then ignore
689 690 691 692 693 694
     this special field when merging adjacent fields.  Here's the same
     situation, but with a `boundary' field between the `x' and `y' fields:

	xxx.BBBByyyy

     Here, if point is at the end of `x', the beginning of `y', or
695
     anywhere in-between (within the `boundary' field), merge all
696 697 698
     three fields and consider the beginning as being the beginning of
     the `x' field, and the end as being the end of the `y' field.  */

699
  if (beg)
700 701 702 703 704 705 706 707
    {
      if (at_field_start)
	/* POS is at the edge of a field, and we should consider it as
	   the beginning of the following field.  */
	*beg = XFASTINT (pos);
      else
	/* Find the previous field boundary.  */
	{
708
	  Lisp_Object p = pos;
709 710
	  if (!NILP (merge_at_boundary) && EQ (before_field, Qboundary))
	    /* Skip a `boundary' field.  */
711
	    p = Fprevious_single_char_property_change (p, Qfield, Qnil,
712
						       beg_limit);
713 714 715 716

	  p = Fprevious_single_char_property_change (p, Qfield, Qnil,
						     beg_limit);
	  *beg = NILP (p) ? BEGV : XFASTINT (p);
717 718
	}
    }
719 720

  if (end)
721 722 723 724 725 726 727 728 729 730
    {
      if (at_field_end)
	/* POS is at the edge of a field, and we should consider it as
	   the end of the previous field.  */
	*end = XFASTINT (pos);
      else
	/* Find the next field boundary.  */
	{
	  if (!NILP (merge_at_boundary) && EQ (after_field, Qboundary))
	    /* Skip a `boundary' field.  */
731 732
	    pos = Fnext_single_char_property_change (pos, Qfield, Qnil,
						     end_limit);
733

734 735
	  pos = Fnext_single_char_property_change (pos, Qfield, Qnil,
						   end_limit);
736 737 738
	  *end = NILP (pos) ? ZV : XFASTINT (pos);
	}
    }
739
}
740

741

742
DEFUN ("delete-field", Fdelete_field, Sdelete_field, 0, 1, 0,
743
       doc: /* Delete the field surrounding POS.
Pavel Janík's avatar
Pavel Janík committed
744
A field is a region of text with the same `field' property.
Thien-Thi Nguyen's avatar
Thien-Thi Nguyen committed
745
If POS is nil, the value of point is used for POS.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
746
  (Lisp_Object pos)
747
{
748
  ptrdiff_t beg, end;
749
  find_field (pos, Qnil, Qnil, &beg, Qnil, &end);
750 751
  if (beg != end)
    del_range (beg, end);
752
  return Qnil;
753 754 755
}

DEFUN ("field-string", Ffield_string, Sfield_string, 0, 1, 0,
756
       doc: /* Return the contents of the field surrounding POS as a string.
Pavel Janík's avatar
Pavel Janík committed
757
A field is a region of text with the same `field' property.
Thien-Thi Nguyen's avatar
Thien-Thi Nguyen committed
758
If POS is nil, the value of point is used for POS.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
759
  (Lisp_Object pos)
760
{
761
  ptrdiff_t beg, end;
762
  find_field (pos, Qnil, Qnil, &beg, Qnil, &end);
763 764 765 766
  return make_buffer_string (beg, end, 1);
}

DEFUN ("field-string-no-properties", Ffield_string_no_properties, Sfield_string_no_properties, 0, 1, 0,
767
       doc: /* Return the contents of the field around POS, without text properties.
Pavel Janík's avatar
Pavel Janík committed
768
A field is a region of text with the same `field' property.
Thien-Thi Nguyen's avatar
Thien-Thi Nguyen committed
769
If POS is nil, the value of point is used for POS.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
770
  (Lisp_Object pos)
771
{
772
  ptrdiff_t beg, end;
773
  find_field (pos, Qnil, Qnil, &beg, Qnil, &end);
774 775 776
  return make_buffer_string (beg, end, 0);
}

777
DEFUN ("field-beginning", Ffield_beginning, Sfield_beginning, 0, 3, 0,
778
       doc: /* Return the beginning of the field surrounding POS.
Pavel Janík's avatar
Pavel Janík committed
779 780 781
A field is a region of text with the same `field' property.
If POS is nil, the value of point is used for POS.
If ESCAPE-FROM-EDGE is non-nil and POS is at the beginning of its
782 783
field, then the beginning of the *previous* field is returned.
If LIMIT is non-nil, it is a buffer position; if the beginning of the field
Thien-Thi Nguyen's avatar
Thien-Thi Nguyen committed
784
is before LIMIT, then LIMIT will be returned instead.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
785
  (Lisp_Object pos, Lisp_Object escape_from_edge, Lisp_Object limit)
786
{
787
  ptrdiff_t beg;
788
  find_field (pos, escape_from_edge, limit, &beg, Qnil, 0);
789 790 791
  return make_number (beg);
}

Paul Eggert's avatar
Paul Eggert committed
792
DEFUN ("field-end", Ffield_end, Sfield_end, 0, 3, 0,
793
       doc: /* Return the end of the field surrounding POS.
Pavel Janík's avatar
Pavel Janík committed
794 795 796
A field is a region of text with the same `field' property.
If POS is nil, the value of point is used for POS.
If ESCAPE-FROM-EDGE is non-nil and POS is at the end of its field,
797 798
then the end of the *following* field is returned.
If LIMIT is non-nil, it is a buffer position; if the end of the field
Thien-Thi Nguyen's avatar
Thien-Thi Nguyen committed
799
is after LIMIT, then LIMIT will be returned instead.  */)
Dan Nicolaescu's avatar
Dan Nicolaescu committed
800
  (Lisp_Object pos, Lisp_Object escape_from_edge, Lisp_Object limit)
801
{
802
  ptrdiff_t end;
803
  find_field (pos, escape_from_edge, Qnil, 0, limit, &end);
804 805 806
  return make_number (end);
}

Paul Eggert's avatar
Paul Eggert committed
807
DEFUN ("constrain-to-field", Fconstrain_to_field, Sconstrain_to_field, 2, 5, 0,
808
       doc: /* Return the position closest to NEW-POS that is in the same field as OLD-POS.
Pavel Janík's avatar
Pavel Janík committed
809
A field is a region of text with the same `field' property.
810 811 812 813

If NEW-POS is nil, then use the current point instead, and move point
to the resulting constrained position, in addition to returning that
position.
Pavel Janík's avatar
Pavel Janík committed
814 815 816 817 818 819 820 821 822 823 824 825 826

If OLD-POS is at the boundary of two fields, then the allowable
positions for NEW-POS depends on the value of the optional argument
ESCAPE-FROM-EDGE: If ESCAPE-FROM-EDGE is nil, then NEW-POS is
constrained to the field that has the same `field' char-property
as any new characters inserted at OLD-POS, whereas if ESCAPE-FROM-EDGE
is non-nil, NEW-POS is constrained to the union of the two adjacent
fields.  Additionally, if two fields are separated by another field with
the special value `boundary', then any point within this special field is
also considered to be `on the boundary'.

If the optional argument ONLY-IN-LINE is non-nil and constraining
NEW-POS would move it to a different line, NEW-POS is returned
827
unconstrained.  This is useful for commands that move by line, like
Pavel Janík's avatar
Pavel Janík committed
828 829 830 831 832 833
\\[next-line] or \\[beginning-of-line], which should generally respect field boundaries
only in the case where they can still move to the right line.

If the optional argument INHIBIT-CAPTURE-PROPERTY is non-nil, and OLD-POS has
a non-nil property of that name, then any field boundaries are ignored.

834
Field boundaries are not noticed if `inhibit-field-text-motion' is non-nil.  */)
835 836
  (Lisp_Object new_pos, Lisp_Object old_pos, Lisp_Object escape_from_edge,
   Lisp_Object only_in_line, Lisp_Object inhibit_capture_property)
837 838
{
  /* If non-zero, then the original point, before re-positioning.  */
839
  ptrdiff_t orig_point = 0;
840
  bool fwd;
841
  Lisp_Object prev_old, prev_new;
842

843 844 845 846 847 848 849
  if (NILP (new_pos))
    /* Use the current point, and afterwards, set it.  */
    {
      orig_point = PT;
      XSETFASTINT (new_pos, PT);
    }

850 851 852
  CHECK_NUMBER_COERCE_MARKER (new_pos);
  CHECK_NUMBER_COERCE_MARKER (old_pos);

853
  fwd = (XINT (new_pos) > XINT (old_pos));
854

855 856
  prev_old = make_number (XINT (old_pos) - 1);
  prev_new = make_number (XINT (new_pos) - 1);
857

858 859
  if (NILP (Vinhibit_field_text_motion)
      && !EQ (new_pos, old_pos)
860 861
      && (!NILP (Fget_char_property (new_pos, Qfield, Qnil))
          || !NILP (Fget_char_property (old_pos, Qfield, Qnil))
862
          /* To recognize field boundaries, we must also look at the
863
             previous positions; we could use `Fget_pos_property'
864 865 866
             instead, but in itself that would fail inside non-sticky
             fields (like comint prompts).  */
          || (XFASTINT (new_pos) > BEGV
867
              && !NILP (Fget_char_property (prev_new, Qfield, Qnil)))
868
          || (XFASTINT (old_pos) > BEGV
869
              && !NILP (Fget_char_property (prev_old, Qfield, Qnil))))
870
      && (NILP (inhibit_capture_property)
871 872 873
          /* Field boundaries are again a problem; but now we must
             decide the case exactly, so we need to call
             `get_pos_property' as well.  */
874
          || (NILP (Fget_pos_property (old_pos, inhibit_capture_property, Qnil))
875
              && (XFASTINT (old_pos) <= BEGV
876 877 878 879
                  || NILP (Fget_char_property
			   (old_pos, inhibit_capture_property, Qnil))
                  || NILP (Fget_char_property
			   (prev_old, inhibit_capture_property, Qnil))))))
880 881
    /* It is possible that NEW_POS is not within the same field as
       OLD_POS; try to move NEW_POS so that it is.  */
882
    {
883
      ptrdiff_t shortage;
884 885 886
      Lisp_Object field_bound;

      if (fwd)
887
	field_bound = Ffield_end (old_pos, escape_from_edge, new_pos);
888
      else
889
	field_bound = Ffield_beginning (old_pos, escape_from_edge, new_pos);
890

891 892 893 894 895 896 897 898
      if (/* See if ESCAPE_FROM_EDGE caused FIELD_BOUND to jump to the
             other side of NEW_POS, which would mean that NEW_POS is
             already acceptable, and it's not necessary to constrain it
             to FIELD_BOUND.  */
	  ((XFASTINT (field_bound) < XFASTINT (new_pos)) ? fwd : !fwd)
	  /* NEW_POS should be constrained, but only if either
	     ONLY_IN_LINE is nil (in which case any constraint is OK),
	     or NEW_POS and FIELD_BOUND are on the same line (in which
899
	     case the constraint is OK even if ONLY_IN_LINE is non-nil).  */
900 901 902 903
	  && (NILP (only_in_line)
	      /* This is the ONLY_IN_LINE case, check that NEW_POS and
		 FIELD_BOUND are on the same line by seeing whether
		 there's an intervening newline or not.  */
904 905
	      || (find_newline (XFASTINT (new_pos), -1,
				XFASTINT (field_bound), -1,
906
				fwd ? -1 : 1, &shortage, NULL, 1),
907
		  shortage != 0)))
908 909 910 911 912 913 914 915 916 917
	/* Constrain NEW_POS to FIELD_BOUND.  */
	new_pos = field_bound;

      if (orig_point && XFASTINT (new_pos) != orig_point)
	/* The NEW_POS argument was originally nil, so automatically set PT. */
	SET_PT (XFASTINT (new_pos));
    }

  return new_pos;
}
918

919

Paul Eggert's avatar
Paul Eggert committed
920
DEFUN ("line-beginning-position",
921
       Fline_beginning_position, Sline_beginning_position, 0, 1, 0,
922
       doc: /* Return the character position of the first character on the current line.
Chong Yidong's avatar
Chong Yidong committed
923 924
With optional argument N, scan forward N - 1 lines first.
If the scan reaches the end of the buffer, return that position.