aboutsummaryrefslogtreecommitdiff
path: root/gdb/completer.c
blob: bafcb503b91e73ae6fa575a0ccedd9f5d0d61a51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
/* Line completion stuff for GDB, the GNU debugger.
   Copyright (C) 2000-2015 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "filenames.h"		/* For DOSish file names.  */
#include "language.h"
#include "gdb_signals.h"
#include "target.h"
#include "reggroups.h"
#include "user-regs.h"
#include "arch-utils.h"
#include "location.h"

#include "cli/cli-decode.h"

/* FIXME: This is needed because of lookup_cmd_1 ().  We should be
   calling a hook instead so we eliminate the CLI dependency.  */
#include "gdbcmd.h"

/* Needed for rl_completer_word_break_characters() and for
   rl_filename_completion_function.  */
#include "readline/readline.h"

/* readline defines this.  */
#undef savestring

#include "completer.h"

/* An enumeration of the various things a user might
   attempt to complete for a location.  */

enum explicit_location_match_type
{
    /* The filename of a source file.  */
    MATCH_SOURCE,

    /* The name of a function or method.  */
    MATCH_FUNCTION,

    /* The name of a label.  */
    MATCH_LABEL
};

/* Prototypes for local functions.  */
static
char *line_completion_function (const char *text, int matches, 
				char *line_buffer,
				int point);

/* readline uses the word breaks for two things:
   (1) In figuring out where to point the TEXT parameter to the
   rl_completion_entry_function.  Since we don't use TEXT for much,
   it doesn't matter a lot what the word breaks are for this purpose,
   but it does affect how much stuff M-? lists.
   (2) If one of the matches contains a word break character, readline
   will quote it.  That's why we switch between
   current_language->la_word_break_characters() and
   gdb_completer_command_word_break_characters.  I'm not sure when
   we need this behavior (perhaps for funky characters in C++ 
   symbols?).  */

/* Variables which are necessary for fancy command line editing.  */

/* When completing on command names, we remove '-' from the list of
   word break characters, since we use it in command names.  If the
   readline library sees one in any of the current completion strings,
   it thinks that the string needs to be quoted and automatically
   supplies a leading quote.  */
static char *gdb_completer_command_word_break_characters =
" \t\n!@#$%^&*()+=|~`}{[]\"';:?/>.<,";

/* When completing on file names, we remove from the list of word
   break characters any characters that are commonly used in file
   names, such as '-', '+', '~', etc.  Otherwise, readline displays
   incorrect completion candidates.  */
#ifdef HAVE_DOS_BASED_FILE_SYSTEM
/* MS-DOS and MS-Windows use colon as part of the drive spec, and most
   programs support @foo style response files.  */
static char *gdb_completer_file_name_break_characters = " \t\n*|\"';?><@";
#else
static char *gdb_completer_file_name_break_characters = " \t\n*|\"';:?><";
#endif

/* Characters that can be used to quote completion strings.  Note that
   we can't include '"' because the gdb C parser treats such quoted
   sequences as strings.  */
static char *gdb_completer_quote_characters = "'";

/* Accessor for some completer data that may interest other files.  */

char *
get_gdb_completer_quote_characters (void)
{
  return gdb_completer_quote_characters;
}

/* Line completion interface function for readline.  */

char *
readline_line_completion_function (const char *text, int matches)
{
  return line_completion_function (text, matches, 
				   rl_line_buffer, rl_point);
}

/* This can be used for functions which don't want to complete on
   symbols but don't want to complete on anything else either.  */
VEC (char_ptr) *
noop_completer (struct cmd_list_element *ignore, 
		const char *text, const char *prefix)
{
  return NULL;
}

/* Complete on filenames.  */
VEC (char_ptr) *
filename_completer (struct cmd_list_element *ignore, 
		    const char *text, const char *word)
{
  int subsequent_name;
  VEC (char_ptr) *return_val = NULL;

  subsequent_name = 0;
  while (1)
    {
      char *p, *q;

      p = rl_filename_completion_function (text, subsequent_name);
      if (p == NULL)
	break;
      /* We need to set subsequent_name to a non-zero value before the
	 continue line below, because otherwise, if the first file
	 seen by GDB is a backup file whose name ends in a `~', we
	 will loop indefinitely.  */
      subsequent_name = 1;
      /* Like emacs, don't complete on old versions.  Especially
         useful in the "source" command.  */
      if (p[strlen (p) - 1] == '~')
	{
	  xfree (p);
	  continue;
	}

      if (word == text)
	/* Return exactly p.  */
	q = p;
      else if (word > text)
	{
	  /* Return some portion of p.  */
	  q = (char *) xmalloc (strlen (p) + 5);
	  strcpy (q, p + (word - text));
	  xfree (p);
	}
      else
	{
	  /* Return some of TEXT plus p.  */
	  q = (char *) xmalloc (strlen (p) + (text - word) + 5);
	  strncpy (q, word, text - word);
	  q[text - word] = '\0';
	  strcat (q, p);
	  xfree (p);
	}
      VEC_safe_push (char_ptr, return_val, q);
    }
#if 0
  /* There is no way to do this just long enough to affect quote
     inserting without also affecting the next completion.  This
     should be fixed in readline.  FIXME.  */
  /* Ensure that readline does the right thing
     with respect to inserting quotes.  */
  rl_completer_word_break_characters = "";
#endif
  return return_val;
}

/* Complete on linespecs, which might be of two possible forms:

       file:line
   or
       symbol+offset

   This is intended to be used in commands that set breakpoints
   etc.  */

static VEC (char_ptr) *
linespec_location_completer (struct cmd_list_element *ignore,
			     const char *text, const char *word)
{
  int n_syms, n_files, ix;
  VEC (char_ptr) *fn_list = NULL;
  VEC (char_ptr) *list = NULL;
  const char *p;
  int quote_found = 0;
  int quoted = *text == '\'' || *text == '"';
  int quote_char = '\0';
  const char *colon = NULL;
  char *file_to_match = NULL;
  const char *symbol_start = text;
  const char *orig_text = text;
  size_t text_len;

  /* Do we have an unquoted colon, as in "break foo.c:bar"?  */
  for (p = text; *p != '\0'; ++p)
    {
      if (*p == '\\' && p[1] == '\'')
	p++;
      else if (*p == '\'' || *p == '"')
	{
	  quote_found = *p;
	  quote_char = *p++;
	  while (*p != '\0' && *p != quote_found)
	    {
	      if (*p == '\\' && p[1] == quote_found)
		p++;
	      p++;
	    }

	  if (*p == quote_found)
	    quote_found = 0;
	  else
	    break;		/* Hit the end of text.  */
	}
#if HAVE_DOS_BASED_FILE_SYSTEM
      /* If we have a DOS-style absolute file name at the beginning of
	 TEXT, and the colon after the drive letter is the only colon
	 we found, pretend the colon is not there.  */
      else if (p < text + 3 && *p == ':' && p == text + 1 + quoted)
	;
#endif
      else if (*p == ':' && !colon)
	{
	  colon = p;
	  symbol_start = p + 1;
	}
      else if (strchr (current_language->la_word_break_characters(), *p))
	symbol_start = p + 1;
    }

  if (quoted)
    text++;
  text_len = strlen (text);

  /* Where is the file name?  */
  if (colon)
    {
      char *s;

      file_to_match = (char *) xmalloc (colon - text + 1);
      strncpy (file_to_match, text, colon - text + 1);
      /* Remove trailing colons and quotes from the file name.  */
      for (s = file_to_match + (colon - text);
	   s > file_to_match;
	   s--)
	if (*s == ':' || *s == quote_char)
	  *s = '\0';
    }
  /* If the text includes a colon, they want completion only on a
     symbol name after the colon.  Otherwise, we need to complete on
     symbols as well as on files.  */
  if (colon)
    {
      list = make_file_symbol_completion_list (symbol_start, word,
					       file_to_match);
      xfree (file_to_match);
    }
  else
    {
      list = make_symbol_completion_list (symbol_start, word);
      /* If text includes characters which cannot appear in a file
	 name, they cannot be asking for completion on files.  */
      if (strcspn (text, 
		   gdb_completer_file_name_break_characters) == text_len)
	fn_list = make_source_files_completion_list (text, text);
    }

  n_syms = VEC_length (char_ptr, list);
  n_files = VEC_length (char_ptr, fn_list);

  /* Catenate fn_list[] onto the end of list[].  */
  if (!n_syms)
    {
      VEC_free (char_ptr, list); /* Paranoia.  */
      list = fn_list;
      fn_list = NULL;
    }
  else
    {
      char *fn;

      for (ix = 0; VEC_iterate (char_ptr, fn_list, ix, fn); ++ix)
	VEC_safe_push (char_ptr, list, fn);
      VEC_free (char_ptr, fn_list);
    }

  if (n_syms && n_files)
    {
      /* Nothing.  */
    }
  else if (n_files)
    {
      char *fn;

      /* If we only have file names as possible completion, we should
	 bring them in sync with what rl_complete expects.  The
	 problem is that if the user types "break /foo/b TAB", and the
	 possible completions are "/foo/bar" and "/foo/baz"
	 rl_complete expects us to return "bar" and "baz", without the
	 leading directories, as possible completions, because `word'
	 starts at the "b".  But we ignore the value of `word' when we
	 call make_source_files_completion_list above (because that
	 would not DTRT when the completion results in both symbols
	 and file names), so make_source_files_completion_list returns
	 the full "/foo/bar" and "/foo/baz" strings.  This produces
	 wrong results when, e.g., there's only one possible
	 completion, because rl_complete will prepend "/foo/" to each
	 candidate completion.  The loop below removes that leading
	 part.  */
      for (ix = 0; VEC_iterate (char_ptr, list, ix, fn); ++ix)
	{
	  memmove (fn, fn + (word - text),
		   strlen (fn) + 1 - (word - text));
	}
    }
  else if (!n_syms)
    {
      /* No completions at all.  As the final resort, try completing
	 on the entire text as a symbol.  */
      list = make_symbol_completion_list (orig_text, word);
    }

  return list;
}

/* A helper function to collect explicit location matches for the given
   LOCATION, which is attempting to match on WORD.  */

static VEC (char_ptr) *
collect_explicit_location_matches (struct event_location *location,
				   enum explicit_location_match_type what,
				   const char *word)
{
  VEC (char_ptr) *matches = NULL;
  const struct explicit_location *explicit_loc
    = get_explicit_location (location);

  switch (what)
    {
    case MATCH_SOURCE:
      {
	const char *text = (explicit_loc->source_filename == NULL
			    ? "" : explicit_loc->source_filename);

	matches = make_source_files_completion_list (text, word);
      }
      break;

    case MATCH_FUNCTION:
      {
	const char *text = (explicit_loc->function_name == NULL
			    ? "" : explicit_loc->function_name);

	if (explicit_loc->source_filename != NULL)
	  {
	    const char *filename = explicit_loc->source_filename;

	    matches = make_file_symbol_completion_list (text, word, filename);
	  }
	else
	  matches = make_symbol_completion_list (text, word);
      }
      break;

    case MATCH_LABEL:
      /* Not supported.  */
      break;

    default:
      gdb_assert_not_reached ("unhandled explicit_location_match_type");
    }

  return matches;
}

/* A convenience macro to (safely) back up P to the previous word.  */

static const char *
backup_text_ptr (const char *p, const char *text)
{
  while (p > text && isspace (*p))
    --p;
  for (; p > text && !isspace (p[-1]); --p)
    ;

  return p;
}

/* A completer function for explicit locations.  This function
   completes both options ("-source", "-line", etc) and values.  */

static VEC (char_ptr) *
explicit_location_completer (struct cmd_list_element *ignore,
			     struct event_location *location,
			     const char *text, const char *word)
{
  const char *p;
  VEC (char_ptr) *matches = NULL;

  /* Find the beginning of the word.  This is necessary because
     we need to know if we are completing an option name or value.  We
     don't get the leading '-' from the completer.  */
  p = backup_text_ptr (word, text);

  if (*p == '-')
    {
      /* Completing on option name.  */
      static const char *const keywords[] =
	{
	  "source",
	  "function",
	  "line",
	  "label",
	  NULL
	};

      /* Skip over the '-'.  */
      ++p;

      return complete_on_enum (keywords, p, p);
    }
  else
    {
      /* Completing on value (or unknown).  Get the previous word to see what
	 the user is completing on.  */
      size_t len, offset;
      const char *new_word, *end;
      enum explicit_location_match_type what;
      struct explicit_location *explicit_loc
	= get_explicit_location (location);

      /* Backup P to the previous word, which should be the option
	 the user is attempting to complete.  */
      offset = word - p;
      end = --p;
      p = backup_text_ptr (p, text);
      len = end - p;

      if (strncmp (p, "-source", len) == 0)
	{
	  what = MATCH_SOURCE;
	  new_word = explicit_loc->source_filename + offset;
	}
      else if (strncmp (p, "-function", len) == 0)
	{
	  what = MATCH_FUNCTION;
	  new_word = explicit_loc->function_name + offset;
	}
      else if (strncmp (p, "-label", len) == 0)
	{
	  what = MATCH_LABEL;
	  new_word = explicit_loc->label_name + offset;
	}
      else
	{
	  /* The user isn't completing on any valid option name,
	     e.g., "break -source foo.c [tab]".  */
	  return NULL;
	}

      /* If the user hasn't entered a search expression, e.g.,
	 "break -function <TAB><TAB>", new_word will be NULL, but
	 search routines require non-NULL search words.  */
      if (new_word == NULL)
	new_word = "";

      /* Now gather matches  */
      matches = collect_explicit_location_matches (location, what, new_word);
    }

  return matches;
}

/* A completer for locations.  */

VEC (char_ptr) *
location_completer (struct cmd_list_element *ignore,
		    const char *text, const char *word)
{
  VEC (char_ptr) *matches = NULL;
  const char *copy = text;
  struct event_location *location;

  location = string_to_explicit_location (&copy, current_language, 1);
  if (location != NULL)
    {
      struct cleanup *cleanup;

      cleanup = make_cleanup_delete_event_location (location);
      matches = explicit_location_completer (ignore, location, text, word);
      do_cleanups (cleanup);
    }
  else
    {
      /* This is an address or linespec location.
	 Right now both of these are handled by the (old) linespec
	 completer.  */
      matches = linespec_location_completer (ignore, text, word);
    }

  return matches;
}

/* Helper for expression_completer which recursively adds field and
   method names from TYPE, a struct or union type, to the array
   OUTPUT.  */
static void
add_struct_fields (struct type *type, VEC (char_ptr) **output,
		   char *fieldname, int namelen)
{
  int i;
  int computed_type_name = 0;
  const char *type_name = NULL;

  type = check_typedef (type);
  for (i = 0; i < TYPE_NFIELDS (type); ++i)
    {
      if (i < TYPE_N_BASECLASSES (type))
	add_struct_fields (TYPE_BASECLASS (type, i),
			   output, fieldname, namelen);
      else if (TYPE_FIELD_NAME (type, i))
	{
	  if (TYPE_FIELD_NAME (type, i)[0] != '\0')
	    {
	      if (! strncmp (TYPE_FIELD_NAME (type, i), 
			     fieldname, namelen))
		VEC_safe_push (char_ptr, *output,
			       xstrdup (TYPE_FIELD_NAME (type, i)));
	    }
	  else if (TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_UNION)
	    {
	      /* Recurse into anonymous unions.  */
	      add_struct_fields (TYPE_FIELD_TYPE (type, i),
				 output, fieldname, namelen);
	    }
	}
    }

  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; --i)
    {
      const char *name = TYPE_FN_FIELDLIST_NAME (type, i);

      if (name && ! strncmp (name, fieldname, namelen))
	{
	  if (!computed_type_name)
	    {
	      type_name = type_name_no_tag (type);
	      computed_type_name = 1;
	    }
	  /* Omit constructors from the completion list.  */
	  if (!type_name || strcmp (type_name, name))
	    VEC_safe_push (char_ptr, *output, xstrdup (name));
	}
    }
}

/* Complete on expressions.  Often this means completing on symbol
   names, but some language parsers also have support for completing
   field names.  */
VEC (char_ptr) *
expression_completer (struct cmd_list_element *ignore, 
		      const char *text, const char *word)
{
  struct type *type = NULL;
  char *fieldname;
  const char *p;
  enum type_code code = TYPE_CODE_UNDEF;

  /* Perform a tentative parse of the expression, to see whether a
     field completion is required.  */
  fieldname = NULL;
  TRY
    {
      type = parse_expression_for_completion (text, &fieldname, &code);
    }
  CATCH (except, RETURN_MASK_ERROR)
    {
      return NULL;
    }
  END_CATCH

  if (fieldname && type)
    {
      for (;;)
	{
	  type = check_typedef (type);
	  if (TYPE_CODE (type) != TYPE_CODE_PTR
	      && TYPE_CODE (type) != TYPE_CODE_REF)
	    break;
	  type = TYPE_TARGET_TYPE (type);
	}

      if (TYPE_CODE (type) == TYPE_CODE_UNION
	  || TYPE_CODE (type) == TYPE_CODE_STRUCT)
	{
	  int flen = strlen (fieldname);
	  VEC (char_ptr) *result = NULL;

	  add_struct_fields (type, &result, fieldname, flen);
	  xfree (fieldname);
	  return result;
	}
    }
  else if (fieldname && code != TYPE_CODE_UNDEF)
    {
      VEC (char_ptr) *result;
      struct cleanup *cleanup = make_cleanup (xfree, fieldname);

      result = make_symbol_completion_type (fieldname, fieldname, code);
      do_cleanups (cleanup);
      return result;
    }
  xfree (fieldname);

  /* Commands which complete on locations want to see the entire
     argument.  */
  for (p = word;
       p > text && p[-1] != ' ' && p[-1] != '\t';
       p--)
    ;

  /* Not ideal but it is what we used to do before...  */
  return location_completer (ignore, p, word);
}

/* See definition in completer.h.  */

void
set_gdb_completion_word_break_characters (completer_ftype *fn)
{
  /* So far we are only interested in differentiating filename
     completers from everything else.  */
  if (fn == filename_completer)
    rl_completer_word_break_characters
      = gdb_completer_file_name_break_characters;
  else
    rl_completer_word_break_characters
      = gdb_completer_command_word_break_characters;
}

/* Here are some useful test cases for completion.  FIXME: These
   should be put in the test suite.  They should be tested with both
   M-? and TAB.

   "show output-" "radix"
   "show output" "-radix"
   "p" ambiguous (commands starting with p--path, print, printf, etc.)
   "p "  ambiguous (all symbols)
   "info t foo" no completions
   "info t " no completions
   "info t" ambiguous ("info target", "info terminal", etc.)
   "info ajksdlfk" no completions
   "info ajksdlfk " no completions
   "info" " "
   "info " ambiguous (all info commands)
   "p \"a" no completions (string constant)
   "p 'a" ambiguous (all symbols starting with a)
   "p b-a" ambiguous (all symbols starting with a)
   "p b-" ambiguous (all symbols)
   "file Make" "file" (word break hard to screw up here)
   "file ../gdb.stabs/we" "ird" (needs to not break word at slash)
 */

typedef enum
{
  handle_brkchars,
  handle_completions,
  handle_help
}
complete_line_internal_reason;


/* Internal function used to handle completions.


   TEXT is the caller's idea of the "word" we are looking at.

   LINE_BUFFER is available to be looked at; it contains the entire
   text of the line.  POINT is the offset in that line of the cursor.
   You should pretend that the line ends at POINT.

   REASON is of type complete_line_internal_reason.

   If REASON is handle_brkchars:
   Preliminary phase, called by gdb_completion_word_break_characters
   function, is used to determine the correct set of chars that are
   word delimiters depending on the current command in line_buffer.
   No completion list should be generated; the return value should be
   NULL.  This is checked by an assertion in that function.

   If REASON is handle_completions:
   Main phase, called by complete_line function, is used to get the list
   of posible completions.

   If REASON is handle_help:
   Special case when completing a 'help' command.  In this case,
   once sub-command completions are exhausted, we simply return NULL.
 */

static VEC (char_ptr) *
complete_line_internal (const char *text, 
			const char *line_buffer, int point,
			complete_line_internal_reason reason)
{
  VEC (char_ptr) *list = NULL;
  char *tmp_command;
  const char *p;
  int ignore_help_classes;
  /* Pointer within tmp_command which corresponds to text.  */
  char *word;
  struct cmd_list_element *c, *result_list;

  /* Choose the default set of word break characters to break
     completions.  If we later find out that we are doing completions
     on command strings (as opposed to strings supplied by the
     individual command completer functions, which can be any string)
     then we will switch to the special word break set for command
     strings, which leaves out the '-' character used in some
     commands.  */
  rl_completer_word_break_characters =
    current_language->la_word_break_characters();

  /* Decide whether to complete on a list of gdb commands or on
     symbols.  */
  tmp_command = (char *) alloca (point + 1);
  p = tmp_command;

  /* The help command should complete help aliases.  */
  ignore_help_classes = reason != handle_help;

  strncpy (tmp_command, line_buffer, point);
  tmp_command[point] = '\0';
  /* Since text always contains some number of characters leading up
     to point, we can find the equivalent position in tmp_command
     by subtracting that many characters from the end of tmp_command.  */
  word = tmp_command + point - strlen (text);

  if (point == 0)
    {
      /* An empty line we want to consider ambiguous; that is, it
	 could be any command.  */
      c = CMD_LIST_AMBIGUOUS;
      result_list = 0;
    }
  else
    {
      c = lookup_cmd_1 (&p, cmdlist, &result_list, ignore_help_classes);
    }

  /* Move p up to the next interesting thing.  */
  while (*p == ' ' || *p == '\t')
    {
      p++;
    }

  if (!c)
    {
      /* It is an unrecognized command.  So there are no
	 possible completions.  */
      list = NULL;
    }
  else if (c == CMD_LIST_AMBIGUOUS)
    {
      const char *q;

      /* lookup_cmd_1 advances p up to the first ambiguous thing, but
	 doesn't advance over that thing itself.  Do so now.  */
      q = p;
      while (*q && (isalnum (*q) || *q == '-' || *q == '_'))
	++q;
      if (q != tmp_command + point)
	{
	  /* There is something beyond the ambiguous
	     command, so there are no possible completions.  For
	     example, "info t " or "info t foo" does not complete
	     to anything, because "info t" can be "info target" or
	     "info terminal".  */
	  list = NULL;
	}
      else
	{
	  /* We're trying to complete on the command which was ambiguous.
	     This we can deal with.  */
	  if (result_list)
	    {
	      if (reason != handle_brkchars)
		list = complete_on_cmdlist (*result_list->prefixlist, p,
					    word, ignore_help_classes);
	    }
	  else
	    {
	      if (reason != handle_brkchars)
		list = complete_on_cmdlist (cmdlist, p, word,
					    ignore_help_classes);
	    }
	  /* Ensure that readline does the right thing with respect to
	     inserting quotes.  */
	  rl_completer_word_break_characters =
	    gdb_completer_command_word_break_characters;
	}
    }
  else
    {
      /* We've recognized a full command.  */

      if (p == tmp_command + point)
	{
	  /* There is no non-whitespace in the line beyond the
	     command.  */

	  if (p[-1] == ' ' || p[-1] == '\t')
	    {
	      /* The command is followed by whitespace; we need to
		 complete on whatever comes after command.  */
	      if (c->prefixlist)
		{
		  /* It is a prefix command; what comes after it is
		     a subcommand (e.g. "info ").  */
		  if (reason != handle_brkchars)
		    list = complete_on_cmdlist (*c->prefixlist, p, word,
						ignore_help_classes);

		  /* Ensure that readline does the right thing
		     with respect to inserting quotes.  */
		  rl_completer_word_break_characters =
		    gdb_completer_command_word_break_characters;
		}
	      else if (reason == handle_help)
		list = NULL;
	      else if (c->enums)
		{
		  if (reason != handle_brkchars)
		    list = complete_on_enum (c->enums, p, word);
		  rl_completer_word_break_characters =
		    gdb_completer_command_word_break_characters;
		}
	      else
		{
		  /* It is a normal command; what comes after it is
		     completed by the command's completer function.  */
		  if (c->completer == filename_completer)
		    {
		      /* Many commands which want to complete on
			 file names accept several file names, as
			 in "run foo bar >>baz".  So we don't want
			 to complete the entire text after the
			 command, just the last word.  To this
			 end, we need to find the beginning of the
			 file name by starting at `word' and going
			 backwards.  */
		      for (p = word;
			   p > tmp_command
			     && strchr (gdb_completer_file_name_break_characters, p[-1]) == NULL;
			   p--)
			;
		      rl_completer_word_break_characters =
			gdb_completer_file_name_break_characters;
		    }
		  if (reason == handle_brkchars
		      && c->completer_handle_brkchars != NULL)
		    (*c->completer_handle_brkchars) (c, p, word);
		  if (reason != handle_brkchars && c->completer != NULL)
		    list = (*c->completer) (c, p, word);
		}
	    }
	  else
	    {
	      /* The command is not followed by whitespace; we need to
		 complete on the command itself, e.g. "p" which is a
		 command itself but also can complete to "print", "ptype"
		 etc.  */
	      const char *q;

	      /* Find the command we are completing on.  */
	      q = p;
	      while (q > tmp_command)
		{
		  if (isalnum (q[-1]) || q[-1] == '-' || q[-1] == '_')
		    --q;
		  else
		    break;
		}

	      if (reason != handle_brkchars)
		list = complete_on_cmdlist (result_list, q, word,
					    ignore_help_classes);

	      /* Ensure that readline does the right thing
		 with respect to inserting quotes.  */
	      rl_completer_word_break_characters =
		gdb_completer_command_word_break_characters;
	    }
	}
      else if (reason == handle_help)
	list = NULL;
      else
	{
	  /* There is non-whitespace beyond the command.  */

	  if (c->prefixlist && !c->allow_unknown)
	    {
	      /* It is an unrecognized subcommand of a prefix command,
		 e.g. "info adsfkdj".  */
	      list = NULL;
	    }
	  else if (c->enums)
	    {
	      if (reason != handle_brkchars)
		list = complete_on_enum (c->enums, p, word);
	    }
	  else
	    {
	      /* It is a normal command.  */
	      if (c->completer == filename_completer)
		{
		  /* See the commentary above about the specifics
		     of file-name completion.  */
		  for (p = word;
		       p > tmp_command
			 && strchr (gdb_completer_file_name_break_characters, 
				    p[-1]) == NULL;
		       p--)
		    ;
		  rl_completer_word_break_characters =
		    gdb_completer_file_name_break_characters;
		}
	      if (reason == handle_brkchars
		  && c->completer_handle_brkchars != NULL)
		(*c->completer_handle_brkchars) (c, p, word);
	      if (reason != handle_brkchars && c->completer != NULL)
		list = (*c->completer) (c, p, word);
	    }
	}
    }

  return list;
}

/* See completer.h.  */

int max_completions = 200;

/* See completer.h.  */

completion_tracker_t
new_completion_tracker (void)
{
  if (max_completions <= 0)
    return NULL;

  return htab_create_alloc (max_completions,
			    htab_hash_string, (htab_eq) streq,
			    NULL, xcalloc, xfree);
}

/* Cleanup routine to free a completion tracker and reset the pointer
   to NULL.  */

static void
free_completion_tracker (void *p)
{
  completion_tracker_t *tracker_ptr = (completion_tracker_t *) p;

  htab_delete (*tracker_ptr);
  *tracker_ptr = NULL;
}

/* See completer.h.  */

struct cleanup *
make_cleanup_free_completion_tracker (completion_tracker_t *tracker_ptr)
{
  if (*tracker_ptr == NULL)
    return make_cleanup (null_cleanup, NULL);

  return make_cleanup (free_completion_tracker, tracker_ptr);
}

/* See completer.h.  */

enum maybe_add_completion_enum
maybe_add_completion (completion_tracker_t tracker, char *name)
{
  void **slot;

  if (max_completions < 0)
    return MAYBE_ADD_COMPLETION_OK;
  if (max_completions == 0)
    return MAYBE_ADD_COMPLETION_MAX_REACHED;

  gdb_assert (tracker != NULL);

  if (htab_elements (tracker) >= max_completions)
    return MAYBE_ADD_COMPLETION_MAX_REACHED;

  slot = htab_find_slot (tracker, name, INSERT);

  if (*slot != HTAB_EMPTY_ENTRY)
    return MAYBE_ADD_COMPLETION_DUPLICATE;

  *slot = name;

  return (htab_elements (tracker) < max_completions
	  ? MAYBE_ADD_COMPLETION_OK
	  : MAYBE_ADD_COMPLETION_OK_MAX_REACHED);
}

void
throw_max_completions_reached_error (void)
{
  throw_error (MAX_COMPLETIONS_REACHED_ERROR, _("Max completions reached."));
}

/* Generate completions all at once.  Returns a vector of unique strings
   allocated with xmalloc.  Returns NULL if there are no completions
   or if max_completions is 0.  If max_completions is non-negative, this will
   return at most max_completions strings.

   TEXT is the caller's idea of the "word" we are looking at.

   LINE_BUFFER is available to be looked at; it contains the entire
   text of the line.

   POINT is the offset in that line of the cursor.  You
   should pretend that the line ends at POINT.  */

VEC (char_ptr) *
complete_line (const char *text, const char *line_buffer, int point)
{
  VEC (char_ptr) *list;
  VEC (char_ptr) *result = NULL;
  struct cleanup *cleanups;
  completion_tracker_t tracker;
  char *candidate;
  int ix, max_reached;

  if (max_completions == 0)
    return NULL;
  list = complete_line_internal (text, line_buffer, point,
				 handle_completions);
  if (max_completions < 0)
    return list;

  tracker = new_completion_tracker ();
  cleanups = make_cleanup_free_completion_tracker (&tracker);
  make_cleanup_free_char_ptr_vec (list);

  /* Do a final test for too many completions.  Individual completers may
     do some of this, but are not required to.  Duplicates are also removed
     here.  Otherwise the user is left scratching his/her head: readline and
     complete_command will remove duplicates, and if removal of duplicates
     there brings the total under max_completions the user may think gdb quit
     searching too early.  */

  for (ix = 0, max_reached = 0;
       !max_reached && VEC_iterate (char_ptr, list, ix, candidate);
       ++ix)
    {
      enum maybe_add_completion_enum add_status;

      add_status = maybe_add_completion (tracker, candidate);

      switch (add_status)
	{
	  case MAYBE_ADD_COMPLETION_OK:
	    VEC_safe_push (char_ptr, result, xstrdup (candidate));
	    break;
	  case MAYBE_ADD_COMPLETION_OK_MAX_REACHED:
	    VEC_safe_push (char_ptr, result, xstrdup (candidate));
	    max_reached = 1;
	    break;
      	  case MAYBE_ADD_COMPLETION_MAX_REACHED:
	    gdb_assert_not_reached ("more than max completions reached");
	  case MAYBE_ADD_COMPLETION_DUPLICATE:
	    break;
	}
    }

  do_cleanups (cleanups);

  return result;
}

/* Complete on command names.  Used by "help".  */
VEC (char_ptr) *
command_completer (struct cmd_list_element *ignore, 
		   const char *text, const char *word)
{
  return complete_line_internal (word, text, 
				 strlen (text), handle_help);
}

/* Complete on signals.  */

VEC (char_ptr) *
signal_completer (struct cmd_list_element *ignore,
		  const char *text, const char *word)
{
  VEC (char_ptr) *return_val = NULL;
  size_t len = strlen (word);
  int signum;
  const char *signame;

  for (signum = GDB_SIGNAL_FIRST; signum != GDB_SIGNAL_LAST; ++signum)
    {
      /* Can't handle this, so skip it.  */
      if (signum == GDB_SIGNAL_0)
	continue;

      signame = gdb_signal_to_name ((enum gdb_signal) signum);

      /* Ignore the unknown signal case.  */
      if (!signame || strcmp (signame, "?") == 0)
	continue;

      if (strncasecmp (signame, word, len) == 0)
	VEC_safe_push (char_ptr, return_val, xstrdup (signame));
    }

  return return_val;
}

/* Bit-flags for selecting what the register and/or register-group
   completer should complete on.  */

enum reg_completer_target
  {
    complete_register_names = 0x1,
    complete_reggroup_names = 0x2
  };
DEF_ENUM_FLAGS_TYPE (enum reg_completer_target, reg_completer_targets);

/* Complete register names and/or reggroup names based on the value passed
   in TARGETS.  At least one bit in TARGETS must be set.  */

static VEC (char_ptr) *
reg_or_group_completer_1 (struct cmd_list_element *ignore,
			  const char *text, const char *word,
			  reg_completer_targets targets)
{
  VEC (char_ptr) *result = NULL;
  size_t len = strlen (word);
  struct gdbarch *gdbarch;
  const char *name;

  gdb_assert ((targets & (complete_register_names
			  | complete_reggroup_names)) != 0);
  gdbarch = get_current_arch ();

  if ((targets & complete_register_names) != 0)
    {
      int i;

      for (i = 0;
	   (name = user_reg_map_regnum_to_name (gdbarch, i)) != NULL;
	   i++)
	{
	  if (*name != '\0' && strncmp (word, name, len) == 0)
	    VEC_safe_push (char_ptr, result, xstrdup (name));
	}
    }

  if ((targets & complete_reggroup_names) != 0)
    {
      struct reggroup *group;

      for (group = reggroup_next (gdbarch, NULL);
	   group != NULL;
	   group = reggroup_next (gdbarch, group))
	{
	  name = reggroup_name (group);
	  if (strncmp (word, name, len) == 0)
	    VEC_safe_push (char_ptr, result, xstrdup (name));
	}
    }

  return result;
}

/* Perform completion on register and reggroup names.  */

VEC (char_ptr) *
reg_or_group_completer (struct cmd_list_element *ignore,
			const char *text, const char *word)
{
  return reg_or_group_completer_1 (ignore, text, word,
				   (complete_register_names
				    | complete_reggroup_names));
}

/* Perform completion on reggroup names.  */

VEC (char_ptr) *
reggroup_completer (struct cmd_list_element *ignore,
		    const char *text, const char *word)
{
  return reg_or_group_completer_1 (ignore, text, word,
				   complete_reggroup_names);
}

/* Get the list of chars that are considered as word breaks
   for the current command.  */

char *
gdb_completion_word_break_characters (void)
{
  VEC (char_ptr) *list;

  list = complete_line_internal (rl_line_buffer, rl_line_buffer, rl_point,
				 handle_brkchars);
  gdb_assert (list == NULL);
  return rl_completer_word_break_characters;
}

/* Generate completions one by one for the completer.  Each time we
   are called return another potential completion to the caller.
   line_completion just completes on commands or passes the buck to
   the command's completer function, the stuff specific to symbol
   completion is in make_symbol_completion_list.

   TEXT is the caller's idea of the "word" we are looking at.

   MATCHES is the number of matches that have currently been collected
   from calling this completion function.  When zero, then we need to
   initialize, otherwise the initialization has already taken place
   and we can just return the next potential completion string.

   LINE_BUFFER is available to be looked at; it contains the entire
   text of the line.  POINT is the offset in that line of the cursor.
   You should pretend that the line ends at POINT.

   Returns NULL if there are no more completions, else a pointer to a
   string which is a possible completion, it is the caller's
   responsibility to free the string.  */

static char *
line_completion_function (const char *text, int matches, 
			  char *line_buffer, int point)
{
  static VEC (char_ptr) *list = NULL;	/* Cache of completions.  */
  static int index;			/* Next cached completion.  */
  char *output = NULL;

  if (matches == 0)
    {
      /* The caller is beginning to accumulate a new set of
         completions, so we need to find all of them now, and cache
         them for returning one at a time on future calls.  */

      if (list)
	{
	  /* Free the storage used by LIST, but not by the strings
	     inside.  This is because rl_complete_internal () frees
	     the strings.  As complete_line may abort by calling
	     `error' clear LIST now.  */
	  VEC_free (char_ptr, list);
	}
      index = 0;
      list = complete_line (text, line_buffer, point);
    }

  /* If we found a list of potential completions during initialization
     then dole them out one at a time.  After returning the last one,
     return NULL (and continue to do so) each time we are called after
     that, until a new list is available.  */

  if (list)
    {
      if (index < VEC_length (char_ptr, list))
	{
	  output = VEC_index (char_ptr, list, index);
	  index++;
	}
    }

#if 0
  /* Can't do this because readline hasn't yet checked the word breaks
     for figuring out whether to insert a quote.  */
  if (output == NULL)
    /* Make sure the word break characters are set back to normal for
       the next time that readline tries to complete something.  */
    rl_completer_word_break_characters =
      current_language->la_word_break_characters();
#endif

  return (output);
}

/* Skip over the possibly quoted word STR (as defined by the quote
   characters QUOTECHARS and the word break characters BREAKCHARS).
   Returns pointer to the location after the "word".  If either
   QUOTECHARS or BREAKCHARS is NULL, use the same values used by the
   completer.  */

const char *
skip_quoted_chars (const char *str, const char *quotechars,
		   const char *breakchars)
{
  char quote_char = '\0';
  const char *scan;

  if (quotechars == NULL)
    quotechars = gdb_completer_quote_characters;

  if (breakchars == NULL)
    breakchars = current_language->la_word_break_characters();

  for (scan = str; *scan != '\0'; scan++)
    {
      if (quote_char != '\0')
	{
	  /* Ignore everything until the matching close quote char.  */
	  if (*scan == quote_char)
	    {
	      /* Found matching close quote.  */
	      scan++;
	      break;
	    }
	}
      else if (strchr (quotechars, *scan))
	{
	  /* Found start of a quoted string.  */
	  quote_char = *scan;
	}
      else if (strchr (breakchars, *scan))
	{
	  break;
	}
    }

  return (scan);
}

/* Skip over the possibly quoted word STR (as defined by the quote
   characters and word break characters used by the completer).
   Returns pointer to the location after the "word".  */

const char *
skip_quoted (const char *str)
{
  return skip_quoted_chars (str, NULL, NULL);
}

/* Return a message indicating that the maximum number of completions
   has been reached and that there may be more.  */

const char *
get_max_completions_reached_message (void)
{
  return _("*** List may be truncated, max-completions reached. ***");
}

/* GDB replacement for rl_display_match_list.
   Readline doesn't provide a clean interface for TUI(curses).
   A hack previously used was to send readline's rl_outstream through a pipe
   and read it from the event loop.  Bleah.  IWBN if readline abstracted
   away all the necessary bits, and this is what this code does.  It
   replicates the parts of readline we need and then adds an abstraction
   layer, currently implemented as struct match_list_displayer, so that both
   CLI and TUI can use it.  We copy all this readline code to minimize
   GDB-specific mods to readline.  Once this code performs as desired then
   we can submit it to the readline maintainers.

   N.B. A lot of the code is the way it is in order to minimize differences
   from readline's copy.  */

/* Not supported here.  */
#undef VISIBLE_STATS

#if defined (HANDLE_MULTIBYTE)
#define MB_INVALIDCH(x) ((x) == (size_t)-1 || (x) == (size_t)-2)
#define MB_NULLWCH(x)   ((x) == 0)
#endif

#define ELLIPSIS_LEN	3

/* gdb version of readline/complete.c:get_y_or_n.
   'y' -> returns 1, and 'n' -> returns 0.
   Also supported: space == 'y', RUBOUT == 'n', ctrl-g == start over.
   If FOR_PAGER is non-zero, then also supported are:
   NEWLINE or RETURN -> returns 2, and 'q' -> returns 0.  */

static int
gdb_get_y_or_n (int for_pager, const struct match_list_displayer *displayer)
{
  int c;

  for (;;)
    {
      RL_SETSTATE (RL_STATE_MOREINPUT);
      c = displayer->read_key (displayer);
      RL_UNSETSTATE (RL_STATE_MOREINPUT);

      if (c == 'y' || c == 'Y' || c == ' ')
	return 1;
      if (c == 'n' || c == 'N' || c == RUBOUT)
	return 0;
      if (c == ABORT_CHAR || c < 0)
	{
	  /* Readline doesn't erase_entire_line here, but without it the
	     --More-- prompt isn't erased and neither is the text entered
	     thus far redisplayed.  */
	  displayer->erase_entire_line (displayer);
	  /* Note: The arguments to rl_abort are ignored.  */
	  rl_abort (0, 0);
	}
      if (for_pager && (c == NEWLINE || c == RETURN))
	return 2;
      if (for_pager && (c == 'q' || c == 'Q'))
	return 0;
      displayer->beep (displayer);
    }
}

/* Pager function for tab-completion.
   This is based on readline/complete.c:_rl_internal_pager.
   LINES is the number of lines of output displayed thus far.
   Returns:
   -1 -> user pressed 'n' or equivalent,
   0 -> user pressed 'y' or equivalent,
   N -> user pressed NEWLINE or equivalent and N is LINES - 1.  */

static int
gdb_display_match_list_pager (int lines,
			      const struct match_list_displayer *displayer)
{
  int i;

  displayer->puts (displayer, "--More--");
  displayer->flush (displayer);
  i = gdb_get_y_or_n (1, displayer);
  displayer->erase_entire_line (displayer);
  if (i == 0)
    return -1;
  else if (i == 2)
    return (lines - 1);
  else
    return 0;
}

/* Return non-zero if FILENAME is a directory.
   Based on readline/complete.c:path_isdir.  */

static int
gdb_path_isdir (const char *filename)
{
  struct stat finfo;

  return (stat (filename, &finfo) == 0 && S_ISDIR (finfo.st_mode));
}

/* Return the portion of PATHNAME that should be output when listing
   possible completions.  If we are hacking filename completion, we
   are only interested in the basename, the portion following the
   final slash.  Otherwise, we return what we were passed.  Since
   printing empty strings is not very informative, if we're doing
   filename completion, and the basename is the empty string, we look
   for the previous slash and return the portion following that.  If
   there's no previous slash, we just return what we were passed.

   Based on readline/complete.c:printable_part.  */

static char *
gdb_printable_part (char *pathname)
{
  char *temp, *x;

  if (rl_filename_completion_desired == 0)	/* don't need to do anything */
    return (pathname);

  temp = strrchr (pathname, '/');
#if defined (__MSDOS__)
  if (temp == 0 && ISALPHA ((unsigned char)pathname[0]) && pathname[1] == ':')
    temp = pathname + 1;
#endif

  if (temp == 0 || *temp == '\0')
    return (pathname);
  /* If the basename is NULL, we might have a pathname like '/usr/src/'.
     Look for a previous slash and, if one is found, return the portion
     following that slash.  If there's no previous slash, just return the
     pathname we were passed. */
  else if (temp[1] == '\0')
    {
      for (x = temp - 1; x > pathname; x--)
        if (*x == '/')
          break;
      return ((*x == '/') ? x + 1 : pathname);
    }
  else
    return ++temp;
}

/* Compute width of STRING when displayed on screen by print_filename.
   Based on readline/complete.c:fnwidth.  */

static int
gdb_fnwidth (const char *string)
{
  int width, pos;
#if defined (HANDLE_MULTIBYTE)
  mbstate_t ps;
  int left, w;
  size_t clen;
  wchar_t wc;

  left = strlen (string) + 1;
  memset (&ps, 0, sizeof (mbstate_t));
#endif

  width = pos = 0;
  while (string[pos])
    {
      if (CTRL_CHAR (string[pos]) || string[pos] == RUBOUT)
	{
	  width += 2;
	  pos++;
	}
      else
	{
#if defined (HANDLE_MULTIBYTE)
	  clen = mbrtowc (&wc, string + pos, left - pos, &ps);
	  if (MB_INVALIDCH (clen))
	    {
	      width++;
	      pos++;
	      memset (&ps, 0, sizeof (mbstate_t));
	    }
	  else if (MB_NULLWCH (clen))
	    break;
	  else
	    {
	      pos += clen;
	      w = wcwidth (wc);
	      width += (w >= 0) ? w : 1;
	    }
#else
	  width++;
	  pos++;
#endif
	}
    }

  return width;
}

/* Print TO_PRINT, one matching completion.
   PREFIX_BYTES is number of common prefix bytes.
   Based on readline/complete.c:fnprint.  */

static int
gdb_fnprint (const char *to_print, int prefix_bytes,
	     const struct match_list_displayer *displayer)
{
  int printed_len, w;
  const char *s;
#if defined (HANDLE_MULTIBYTE)
  mbstate_t ps;
  const char *end;
  size_t tlen;
  int width;
  wchar_t wc;

  end = to_print + strlen (to_print) + 1;
  memset (&ps, 0, sizeof (mbstate_t));
#endif

  printed_len = 0;

  /* Don't print only the ellipsis if the common prefix is one of the
     possible completions */
  if (to_print[prefix_bytes] == '\0')
    prefix_bytes = 0;

  if (prefix_bytes)
    {
      char ellipsis;

      ellipsis = (to_print[prefix_bytes] == '.') ? '_' : '.';
      for (w = 0; w < ELLIPSIS_LEN; w++)
	displayer->putch (displayer, ellipsis);
      printed_len = ELLIPSIS_LEN;
    }

  s = to_print + prefix_bytes;
  while (*s)
    {
      if (CTRL_CHAR (*s))
        {
          displayer->putch (displayer, '^');
          displayer->putch (displayer, UNCTRL (*s));
          printed_len += 2;
          s++;
#if defined (HANDLE_MULTIBYTE)
	  memset (&ps, 0, sizeof (mbstate_t));
#endif
        }
      else if (*s == RUBOUT)
	{
	  displayer->putch (displayer, '^');
	  displayer->putch (displayer, '?');
	  printed_len += 2;
	  s++;
#if defined (HANDLE_MULTIBYTE)
	  memset (&ps, 0, sizeof (mbstate_t));
#endif
	}
      else
	{
#if defined (HANDLE_MULTIBYTE)
	  tlen = mbrtowc (&wc, s, end - s, &ps);
	  if (MB_INVALIDCH (tlen))
	    {
	      tlen = 1;
	      width = 1;
	      memset (&ps, 0, sizeof (mbstate_t));
	    }
	  else if (MB_NULLWCH (tlen))
	    break;
	  else
	    {
	      w = wcwidth (wc);
	      width = (w >= 0) ? w : 1;
	    }
	  for (w = 0; w < tlen; ++w)
	    displayer->putch (displayer, s[w]);
	  s += tlen;
	  printed_len += width;
#else
	  displayer->putch (displayer, *s);
	  s++;
	  printed_len++;
#endif
	}
    }

  return printed_len;
}

/* Output TO_PRINT to rl_outstream.  If VISIBLE_STATS is defined and we
   are using it, check for and output a single character for `special'
   filenames.  Return the number of characters we output.
   Based on readline/complete.c:print_filename.  */

static int
gdb_print_filename (char *to_print, char *full_pathname, int prefix_bytes,
		    const struct match_list_displayer *displayer)
{
  int printed_len, extension_char, slen, tlen;
  char *s, c, *new_full_pathname, *dn;
  extern int _rl_complete_mark_directories;

  extension_char = 0;
  printed_len = gdb_fnprint (to_print, prefix_bytes, displayer);

#if defined (VISIBLE_STATS)
 if (rl_filename_completion_desired && (rl_visible_stats || _rl_complete_mark_directories))
#else
 if (rl_filename_completion_desired && _rl_complete_mark_directories)
#endif
    {
      /* If to_print != full_pathname, to_print is the basename of the
	 path passed.  In this case, we try to expand the directory
	 name before checking for the stat character. */
      if (to_print != full_pathname)
	{
	  /* Terminate the directory name. */
	  c = to_print[-1];
	  to_print[-1] = '\0';

	  /* If setting the last slash in full_pathname to a NUL results in
	     full_pathname being the empty string, we are trying to complete
	     files in the root directory.  If we pass a null string to the
	     bash directory completion hook, for example, it will expand it
	     to the current directory.  We just want the `/'. */
	  if (full_pathname == 0 || *full_pathname == 0)
	    dn = "/";
	  else if (full_pathname[0] != '/')
	    dn = full_pathname;
	  else if (full_pathname[1] == 0)
	    dn = "//";		/* restore trailing slash to `//' */
	  else if (full_pathname[1] == '/' && full_pathname[2] == 0)
	    dn = "/";		/* don't turn /// into // */
	  else
	    dn = full_pathname;
	  s = tilde_expand (dn);
	  if (rl_directory_completion_hook)
	    (*rl_directory_completion_hook) (&s);

	  slen = strlen (s);
	  tlen = strlen (to_print);
	  new_full_pathname = (char *)xmalloc (slen + tlen + 2);
	  strcpy (new_full_pathname, s);
	  if (s[slen - 1] == '/')
	    slen--;
	  else
	    new_full_pathname[slen] = '/';
	  new_full_pathname[slen] = '/';
	  strcpy (new_full_pathname + slen + 1, to_print);

#if defined (VISIBLE_STATS)
	  if (rl_visible_stats)
	    extension_char = stat_char (new_full_pathname);
	  else
#endif
	  if (gdb_path_isdir (new_full_pathname))
	    extension_char = '/';

	  xfree (new_full_pathname);
	  to_print[-1] = c;
	}
      else
	{
	  s = tilde_expand (full_pathname);
#if defined (VISIBLE_STATS)
	  if (rl_visible_stats)
	    extension_char = stat_char (s);
	  else
#endif
	    if (gdb_path_isdir (s))
	      extension_char = '/';
	}

      xfree (s);
      if (extension_char)
	{
	  displayer->putch (displayer, extension_char);
	  printed_len++;
	}
    }

  return printed_len;
}

/* GDB version of readline/complete.c:complete_get_screenwidth.  */

static int
gdb_complete_get_screenwidth (const struct match_list_displayer *displayer)
{
  /* Readline has other stuff here which it's not clear we need.  */
  return displayer->width;
}

extern int _rl_completion_prefix_display_length;
extern int _rl_print_completions_horizontally;

EXTERN_C int _rl_qsort_string_compare (const void *, const void *);
typedef int QSFUNC (const void *, const void *);

/* GDB version of readline/complete.c:rl_display_match_list.
   See gdb_display_match_list for a description of MATCHES, LEN, MAX.
   Returns non-zero if all matches are displayed.  */

static int
gdb_display_match_list_1 (char **matches, int len, int max,
			  const struct match_list_displayer *displayer)
{
  int count, limit, printed_len, lines, cols;
  int i, j, k, l, common_length, sind;
  char *temp, *t;
  int page_completions = displayer->height != INT_MAX && pagination_enabled;

  /* Find the length of the prefix common to all items: length as displayed
     characters (common_length) and as a byte index into the matches (sind) */
  common_length = sind = 0;
  if (_rl_completion_prefix_display_length > 0)
    {
      t = gdb_printable_part (matches[0]);
      temp = strrchr (t, '/');
      common_length = temp ? gdb_fnwidth (temp) : gdb_fnwidth (t);
      sind = temp ? strlen (temp) : strlen (t);

      if (common_length > _rl_completion_prefix_display_length && common_length > ELLIPSIS_LEN)
	max -= common_length - ELLIPSIS_LEN;
      else
	common_length = sind = 0;
    }

  /* How many items of MAX length can we fit in the screen window? */
  cols = gdb_complete_get_screenwidth (displayer);
  max += 2;
  limit = cols / max;
  if (limit != 1 && (limit * max == cols))
    limit--;

  /* If cols == 0, limit will end up -1 */
  if (cols < displayer->width && limit < 0)
    limit = 1;

  /* Avoid a possible floating exception.  If max > cols,
     limit will be 0 and a divide-by-zero fault will result. */
  if (limit == 0)
    limit = 1;

  /* How many iterations of the printing loop? */
  count = (len + (limit - 1)) / limit;

  /* Watch out for special case.  If LEN is less than LIMIT, then
     just do the inner printing loop.
	   0 < len <= limit  implies  count = 1. */

  /* Sort the items if they are not already sorted. */
  if (rl_ignore_completion_duplicates == 0 && rl_sort_completion_matches)
    qsort (matches + 1, len, sizeof (char *), (QSFUNC *)_rl_qsort_string_compare);

  displayer->crlf (displayer);

  lines = 0;
  if (_rl_print_completions_horizontally == 0)
    {
      /* Print the sorted items, up-and-down alphabetically, like ls. */
      for (i = 1; i <= count; i++)
	{
	  for (j = 0, l = i; j < limit; j++)
	    {
	      if (l > len || matches[l] == 0)
		break;
	      else
		{
		  temp = gdb_printable_part (matches[l]);
		  printed_len = gdb_print_filename (temp, matches[l], sind,
						    displayer);

		  if (j + 1 < limit)
		    for (k = 0; k < max - printed_len; k++)
		      displayer->putch (displayer, ' ');
		}
	      l += count;
	    }
	  displayer->crlf (displayer);
	  lines++;
	  if (page_completions && lines >= (displayer->height - 1) && i < count)
	    {
	      lines = gdb_display_match_list_pager (lines, displayer);
	      if (lines < 0)
		return 0;
	    }
	}
    }
  else
    {
      /* Print the sorted items, across alphabetically, like ls -x. */
      for (i = 1; matches[i]; i++)
	{
	  temp = gdb_printable_part (matches[i]);
	  printed_len = gdb_print_filename (temp, matches[i], sind, displayer);
	  /* Have we reached the end of this line? */
	  if (matches[i+1])
	    {
	      if (i && (limit > 1) && (i % limit) == 0)
		{
		  displayer->crlf (displayer);
		  lines++;
		  if (page_completions && lines >= displayer->height - 1)
		    {
		      lines = gdb_display_match_list_pager (lines, displayer);
		      if (lines < 0)
			return 0;
		    }
		}
	      else
		for (k = 0; k < max - printed_len; k++)
		  displayer->putch (displayer, ' ');
	    }
	}
      displayer->crlf (displayer);
    }

  return 1;
}

/* Utility for displaying completion list matches, used by both CLI and TUI.

   MATCHES is the list of strings, in argv format, LEN is the number of
   strings in MATCHES, and MAX is the length of the longest string in
   MATCHES.  */

void
gdb_display_match_list (char **matches, int len, int max,
			const struct match_list_displayer *displayer)
{
  /* Readline will never call this if complete_line returned NULL.  */
  gdb_assert (max_completions != 0);

  /* complete_line will never return more than this.  */
  if (max_completions > 0)
    gdb_assert (len <= max_completions);

  if (rl_completion_query_items > 0 && len >= rl_completion_query_items)
    {
      char msg[100];

      /* We can't use *query here because they wait for <RET> which is
	 wrong here.  This follows the readline version as closely as possible
	 for compatibility's sake.  See readline/complete.c.  */

      displayer->crlf (displayer);

      xsnprintf (msg, sizeof (msg),
		 "Display all %d possibilities? (y or n)", len);
      displayer->puts (displayer, msg);
      displayer->flush (displayer);

      if (gdb_get_y_or_n (0, displayer) == 0)
	{
	  displayer->crlf (displayer);
	  return;
	}
    }

  if (gdb_display_match_list_1 (matches, len, max, displayer))
    {
      /* Note: MAX_COMPLETIONS may be -1 or zero, but LEN is always > 0.  */
      if (len == max_completions)
	{
	  /* The maximum number of completions has been reached.  Warn the user
	     that there may be more.  */
	  const char *message = get_max_completions_reached_message ();

	  displayer->puts (displayer, message);
	  displayer->crlf (displayer);
	}
    }
}

extern initialize_file_ftype _initialize_completer; /* -Wmissing-prototypes */

void
_initialize_completer (void)
{
  add_setshow_zuinteger_unlimited_cmd ("max-completions", no_class,
				       &max_completions, _("\
Set maximum number of completion candidates."), _("\
Show maximum number of completion candidates."), _("\
Use this to limit the number of candidates considered\n\
during completion.  Specifying \"unlimited\" or -1\n\
disables limiting.  Note that setting either no limit or\n\
a very large limit can make completion slow."),
				       NULL, NULL, &setlist, &showlist);
}