cplmatch.c

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/*
 * Copyright (c) 2000, 2001 by Martin C. Shepherd.
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, and/or sell copies of the Software, and to permit persons
 * to whom the Software is furnished to do so, provided that the above
 * copyright notice(s) and this permission notice appear in all copies of
 * the Software and that both the above copyright notice(s) and this
 * permission notice appear in supporting documentation.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
 * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 * 
 * Except as contained in this notice, the name of a copyright holder
 * shall not be used in advertising or otherwise to promote the sale, use
 * or other dealings in this Software without prior written authorization
 * of the copyright holder.
 */

/*
 * Standard includes.
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

/*
 * Local includes.
 */
#include "libtecla.h"
#include "stringrp.h"
#include "pathutil.h"
#include "cplfile.h"

/*
 * Specify the number of strings to allocate when the string free-list
 * is exhausted. This also sets the number of elements to expand the
 * matches[] array by whenever it is found to be too small.
 */
#define STR_BLK_FACT 100

/*
 * Set the max length of the error-reporting string. There is no point
 * in this being longer than the width of a typical terminal window.
 * In composing error messages, I have assumed that this number is
 * at least 80, so don't decrease it below 80.
 */
#define ERRLEN 200

/*
 * Completion matches are recorded in containers of the following
 * type.
 */
struct WordCompletion {
  StringGroup *sg;        /* Memory for a group of strings */
  int matches_dim;        /* The allocated size of result.matches[] */
  char errmsg[ERRLEN+1];  /* The error-reporting buffer */
  CplMatches result;      /* Completions to be returned to the caller */
  CompleteFile *cf;       /* The resources used for filename completion */
};

static void cpl_sort_matches(WordCompletion *cpl);
static void cpl_zap_duplicates(WordCompletion *cpl);
static void cpl_clear_completions(WordCompletion *cpl);
static int cpl_cmp_matches(const void *v1, const void *v2);
static int cpl_cmp_suffixes(const void *v1, const void *v2);

/*
 * The new_CplFileConf() constructor sets the integer first member of
 * the returned object to the following magic number. On seeing this,
 * cpl_file_completions() knows when it is passed a valid CplFileConf
 * object.
 */
#define CFC_ID_CODE 4568

/*
 * A pointer to a structure of the following type can be passed to
 * the builtin file-completion callback function to modify its behavior.
 */
struct CplFileConf {
  int id;             /* new_CplFileConf() sets this to CFC_ID_CODE */
  int escaped;        /* If none-zero, backslashes in the input line are */
                      /*  interpreted as escaping special characters and */
                      /*  spaces, and any special characters and spaces in */
                      /*  the listed completions will also be escaped with */
                      /*  added backslashes. This is the default behaviour. */
                      /* If zero, backslashes are interpreted as being */
                      /*  literal parts of the filename, and none are added */
                      /*  to the completion suffixes. */
  int file_start;     /* The index in the input line of the first character */
                      /*  of the filename. If you specify -1 here, */
                      /*  cpl_file_completions() identifies the */
                      /*  the start of the filename by looking backwards for */
                      /*  an unescaped space, or the beginning of the line. */
  CplCheckFn *chk_fn; /* If not zero, this argument specifies a */
                      /*  function to call to ask whether a given */
                      /*  file should be included in the list */
                      /*  of completions. */
  void *chk_data;     /* Anonymous data to be passed to check_fn(). */
};

static void cpl_init_FileConf(CplFileConf *cfc);

/*.......................................................................
 * Create a new string-completion object.
 *
 * Output:
 *  return    WordCompletion *  The new object, or NULL on error.
 */
WordCompletion *new_WordCompletion(void)
{
  WordCompletion *cpl;  /* The object to be returned */
/*
 * Allocate the container.
 */
  cpl = (WordCompletion *) malloc(sizeof(WordCompletion));
  if(!cpl) {
    fprintf(stderr, "new_WordCompletion: Insufficient memory.\n");
    return NULL;
  };
/*
 * Before attempting any operation that might fail, initialize the
 * container at least up to the point at which it can safely be passed
 * to del_WordCompletion().
 */
  cpl->sg = NULL;
  cpl->matches_dim = 0;
  cpl->result.suffix = NULL;
  cpl->result.cont_suffix = NULL;
  cpl->result.matches = NULL;
  cpl->result.nmatch = 0;
  cpl->cf = NULL;
/*
 * Allocate an object that allows a group of strings to be allocated
 * efficiently by placing many of them in contiguous string segments.
 */
  cpl->sg = _new_StringGroup(_pu_pathname_dim());
  if(!cpl->sg)
    return del_WordCompletion(cpl);
/*
 * Allocate an array for matching completions. This will be extended later
 * if needed.
 */
  cpl->matches_dim = STR_BLK_FACT;
  cpl->result.matches = (CplMatch *) malloc(sizeof(cpl->result.matches[0]) *
					    cpl->matches_dim);
  if(!cpl->result.matches) {
    fprintf(stderr,
     "new_WordCompletion: Insufficient memory to allocate array of matches.\n");
    return del_WordCompletion(cpl);
  };
/*
 * Allocate a filename-completion resource object.
 */
  cpl->cf = _new_CompleteFile();
  if(!cpl->cf)
    return del_WordCompletion(cpl);
  return cpl;
}

/*.......................................................................
 * Delete a string-completion object.
 *
 * Input:
 *  cpl    WordCompletion *  The object to be deleted.
 * Output:
 *  return WordCompletion *  The deleted object (always NULL).
 */
WordCompletion *del_WordCompletion(WordCompletion *cpl)
{
  if(cpl) {
    cpl->sg = _del_StringGroup(cpl->sg);
    if(cpl->result.matches) {
      free(cpl->result.matches);
      cpl->result.matches = NULL;
      cpl->cf = _del_CompleteFile(cpl->cf);
    };
    free(cpl);
  };
  return NULL;
}

/*.......................................................................
 * This function is designed to be called by CplMatchFn callback
 * functions. It adds one possible completion of the token that is being
 * completed to an array of completions. If the completion needs any
 * special quoting to be valid when displayed in the input line, this
 * quoting must be included in the string.
 *
 * Input:
 *  cpl     WordCompletion *  The argument of the same name that was passed
 *                            to the calling CplMatchFn callback function.
 *  line        const char *  The input line, as received by the callback
 *                            function.
 *  word_start         int    The index within line[] of the start of the
 *                            word that is being completed.
 *  word_end           int    The index within line[] of the character which
 *                            follows the incomplete word, as received by the
 *                            calling callback function.
 *  suffix      const char *  The appropriately quoted string that could
 *                            be appended to the incomplete token to complete
 *                            it. A copy of this string will be allocated
 *                            internally.
 *  type_suffix const char *  When listing multiple completions, gl_get_line()
 *                            appends this string to the completion to indicate
 *                            its type to the user. If not pertinent pass "".
 *                            Otherwise pass a literal or static string.
 *  cont_suffix const char *  If this turns out to be the only completion,
 *                            gl_get_line() will append this string as
 *                            a continuation. For example, the builtin
 *                            file-completion callback registers a directory
 *                            separator here for directory matches, and a
 *                            space otherwise. If the match were a function
 *                            name you might want to append an open
 *                            parenthesis, etc.. If not relevant pass "".
 *                            Otherwise pass a literal or static string.
 * Output:
 *  return             int    0 - OK.
 *                            1 - Error.
 */
int cpl_add_completion(WordCompletion *cpl, const char *line,
		       int word_start, int word_end, const char *suffix,
		       const char *type_suffix, const char *cont_suffix)
{
  CplMatch *match; /* The container of the new match */
  char *string;    /* A newly allocated copy of the completion string */
/*
 * Check the arguments.
 */
  if(!cpl)
    return 1;
  if(!suffix)
    return 0;
  if(!type_suffix)
    type_suffix = "";
  if(!cont_suffix)
    cont_suffix = "";
/*
 * Do we need to extend the array of matches[]?
 */
  if(cpl->result.nmatch+1 > cpl->matches_dim) {
    int needed = cpl->matches_dim + STR_BLK_FACT;
    CplMatch *matches = (CplMatch *) realloc(cpl->result.matches,
			    sizeof(cpl->result.matches[0]) * needed);
    if(!matches) {
      strcpy(cpl->errmsg, "Insufficient memory to extend array of matches.");
      return 1;
    };
    cpl->result.matches = matches;
    cpl->matches_dim = needed;
  };
/*
 * Allocate memory to store the combined completion prefix and the
 * new suffix.
 */
  string = _sg_alloc_string(cpl->sg, word_end-word_start + strlen(suffix));
  if(!string) {
    strcpy(cpl->errmsg, "Insufficient memory to extend array of matches.");
    return 1;
  };
/*
 * Compose the string.
 */
  strncpy(string, line + word_start, word_end - word_start);
  strcpy(string + word_end - word_start, suffix);
/*
 * Record the new match.
 */
  match = cpl->result.matches + cpl->result.nmatch++;
  match->completion = string;
  match->suffix = string + word_end - word_start;
  match->type_suffix = type_suffix;
/*
 * Record the continuation suffix.
 */
  cpl->result.cont_suffix = cont_suffix;
  return 0;
}

/*.......................................................................
 * Sort the array of matches.
 *
 * Input:
 *  cpl   WordCompletion *  The completion resource object.
 */
static void cpl_sort_matches(WordCompletion *cpl)
{
  qsort(cpl->result.matches, cpl->result.nmatch,
	sizeof(cpl->result.matches[0]), cpl_cmp_matches);
}

/*.......................................................................
 * This is a qsort() comparison function used to sort matches.
 *
 * Input:
 *  v1, v2   void *  Pointers to the two matches to be compared.
 * Output:
 *  return    int    -1 -> v1 < v2.
 *                    0 -> v1 == v2
 *                    1 -> v1 > v2
 */
static int cpl_cmp_matches(const void *v1, const void *v2)
{
  const CplMatch *m1 = (const CplMatch *) v1;
  const CplMatch *m2 = (const CplMatch *) v2;