aboutsummaryrefslogtreecommitdiff
path: root/gdb/completer.c
blob: 44920dd453d1b25d61e4187e0bbfd84564cb81f8 (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
/* Line completion stuff for GDB, the GNU debugger.
   Copyright (C) 2000-2014 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 "exceptions.h"
#include "gdb_signals.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"

/* 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 = xmalloc (strlen (p) + 5);
	  strcpy (q, p + (word - text));
	  xfree (p);
	}
      else
	{
	  /* Return some of TEXT plus p.  */
	  q = 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 locations, which might be of two possible forms:

       file:line
   or
       symbol+offset

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

VEC (char_ptr) *
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;
}

/* 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;

  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;
  volatile struct gdb_exception except;
  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_CATCH (except, RETURN_MASK_ERROR)
    {
      type = parse_expression_for_completion (text, &fieldname, &code);
    }
  if (except.reason < 0)
    return NULL;
  if (fieldname && type)
    {
      for (;;)
	{
	  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);
}

/* 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;
		    }
		  else if (c->completer == location_completer)
		    {
		      /* Commands which complete on locations want to
			 see the entire argument.  */
		      for (p = word;
			   p > tmp_command
			     && p[-1] != ' ' && p[-1] != '\t';
			   p--)
			;
		    }
		  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;
		}
	      else if (c->completer == location_completer)
		{
		  for (p = word;
		       p > tmp_command
			 && p[-1] != ' ' && p[-1] != '\t';
		       p--)
		    ;
		}
	      if (reason != handle_brkchars && c->completer != NULL)
		list = (*c->completer) (c, p, word);
	    }
	}
    }

  return list;
}
/* Generate completions all at once.  Returns a vector of strings.
   Each element is allocated with xmalloc.  It can also return NULL if
   there are no 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.  */

VEC (char_ptr) *
complete_line (const char *text, const char *line_buffer, int point)
{
  return complete_line_internal (text, line_buffer, 
				 point, handle_completions);
}

/* 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);
  enum gdb_signal 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 (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;
}

/* 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);
}