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/* Line completion stuff for GDB, the GNU debugger.

   Copyright (C) 2000, 2001, 2007, 2008, 2009, 2010

   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_assert.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.  */

char **

noop_completer (struct cmd_list_element *ignore, char *text, char *prefix)

{

  return NULL;

}

/* Complete on filenames.  */

char **

filename_completer (struct cmd_list_element *ignore, char *text, char *word)

{

  int subsequent_name;

  char **return_val;

  int return_val_used;

  int return_val_alloced;

  return_val_used = 0;

  /* Small for testing.  */

  return_val_alloced = 1;

  return_val = (char **) xmalloc (return_val_alloced * sizeof (char *));

  subsequent_name = 0;

  while (1)

    {

      char *p, *q;

      p = rl_filename_completion_function (text, subsequent_name);

      if (return_val_used >= return_val_alloced)

        {

          return_val_alloced *= 2;

          return_val =

            (char **) xrealloc (return_val,

                                return_val_alloced * sizeof (char *));

        }

      if (p == NULL)

        {

          return_val[return_val_used++] = p;

          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.  */

        return_val[return_val_used++] = p;

      else if (word > text)

        {

          /* Return some portion of p.  */

          q = xmalloc (strlen (p) + 5);

          strcpy (q, p + (word - text));

          return_val[return_val_used++] = q;

          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);

          return_val[return_val_used++] = q;

          xfree (p);

        }

    }

#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.  */

char **

location_completer (struct cmd_list_element *ignore, char *text, char *word)

{

  int n_syms = 0, n_files = 0;

  char ** fn_list = NULL;

  char ** list = NULL;

  char *p;

  int quote_found = 0;

  int quoted = *text == '\'' || *text == '"';

  int quote_char = '\0';

  char *colon = NULL;

  char *file_to_match = NULL;

  char *symbol_start = text;

  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);

    }

  /* How many completions do we have in both lists?  */

  if (fn_list)

    for ( ; fn_list[n_files]; n_files++)

      ;

  if (list)

    for ( ; list[n_syms]; n_syms++)

      ;

  /* Make list[] large enough to hold both lists, then catenate

     fn_list[] onto the end of list[].  */

  if (n_syms && n_files)

    {

      list = xrealloc (list, (n_syms + n_files + 1) * sizeof (char *));

      memcpy (list + n_syms, fn_list, (n_files + 1) * sizeof (char *));

      xfree (fn_list);

    }

  else if (n_files)

    {

      /* 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 (n_files = 0; fn_list[n_files]; n_files++)

        {

          memmove (fn_list[n_files], fn_list[n_files] + (word - text),

                   strlen (fn_list[n_files]) + 1 - (word - text));

        }

      /* Return just the file-name list as the result.  */

      list = fn_list;

    }

  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);

      xfree (fn_list);

    }

  else

    xfree (fn_list);

  return list;

}

/* Helper for expression_completer which recursively counts the number

   of named fields and methods in a structure or union type.  */

static int

count_struct_fields (struct type *type)

{

  int i, result = 0;

  CHECK_TYPEDEF (type);

  for (i = 0; i < TYPE_NFIELDS (type); ++i)

    {

      if (i < TYPE_N_BASECLASSES (type))

        result += count_struct_fields (TYPE_BASECLASS (type, i));

      else if (TYPE_FIELD_NAME (type, i))

        ++result;

    }

  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; --i)

    {

      if (TYPE_FN_FIELDLIST_NAME (type, i))

        ++result;

    }

  return result;

}

/* Helper for expression_completer which recursively adds field and

   method names from TYPE, a struct or union type, to the array

   OUTPUT.  This function assumes that OUTPUT is correctly-sized.  */

static void

add_struct_fields (struct type *type, int *nextp, char **output,

                   char *fieldname, int namelen)

{

  int i;

  int computed_type_name = 0;

  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), nextp, output,

                           fieldname, namelen);

      else if (TYPE_FIELD_NAME (type, i)

               && ! strncmp (TYPE_FIELD_NAME (type, i), fieldname, namelen))

        {

          output[*nextp] = xstrdup (TYPE_FIELD_NAME (type, i));

          ++*nextp;

        }

    }

  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; --i)

    {

      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))

            {

              output[*nextp] = xstrdup (name);

              ++*nextp;

            }

        }

    }

}

/* Complete on expressions.  Often this means completing on symbol

   names, but some language parsers also have support for completing

   field names.  */

char **

expression_completer (struct cmd_list_element *ignore, char *text, char *word)

{

  struct type *type;

  char *fieldname, *p;

  /* Perform a tentative parse of the expression, to see whether a

     field completion is required.  */

  fieldname = NULL;

  type = parse_field_expression (text, &fieldname);

  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 alloc = count_struct_fields (type);

          int flen = strlen (fieldname);

          int out = 0;

          char **result = (char **) xmalloc ((alloc + 1) * sizeof (char *));

          add_struct_fields (type, &out, result, fieldname, flen);

          result[out] = NULL;

          xfree (fieldname);

          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 char **

complete_line_internal (const char *text, char *line_buffer, int point,

                        complete_line_internal_reason reason)

{

  char **list = NULL;

  char *tmp_command, *p;

  /* 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;

  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 = (struct cmd_list_element *) -1;

      result_list = 0;

    }

  else

    {

      c = lookup_cmd_1 (&p, cmdlist, &result_list, 1);

    }

  /* 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 == (struct cmd_list_element *) -1)

    {

      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);

            }

          else

            {

              if (reason != handle_brkchars)

                list = complete_on_cmdlist (cmdlist, p, word);

            }

          /* 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);

                  /* 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.  */

              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);

              /* Ensure that readline does the right thing

                 with respect to inserting quotes.  */

              rl_completer_word_break_characters =

                gdb_completer_command_word_break_characters;