pcache.c

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 * scan it for files of interest.
 */
    if(node->relative) {
      rst_CacheMem(node->mem);
      if(pca_scan_dir(pc, node->dir, node->mem) < 1)
	continue;
      node->files = node->mem->files;
      node->nfile = node->mem->nfiles;
    };
/*
 * If needed, make a copy of the file-name being matched, with
 * escapes removed. Note that we need to do this anew every loop
 * iteration, because the above call to pca_scan_dir() uses
 * pc->path.
 */
    prefix = pca_prepare_prefix(pc, start_path, prefix_len, ppc->escaped);
    if(!prefix)
      return 1;
/*
 * The directory entries are sorted, so we can perform a binary
 * search for an instance of the prefix being searched for.
 */
    bot = 0;
    top = node->nfile - 1;
    while(top >= bot) {
      int mid = (top + bot)/2;
      int test = strncmp(node->files[mid]+1, prefix, prefix_len);
      if(test > 0)
	top = mid - 1;
      else if(test < 0)
	bot = mid + 1;
      else {
	top = bot = mid;
	break;
      };
    };
/*
 * If we found a match, look to see if any of its neigbors also match.
 */
    if(top == bot) {
      while(--bot >= 0 && strncmp(node->files[bot]+1, prefix, prefix_len) == 0)
	;
      while(++top < node->nfile &&
	    strncmp(node->files[top]+1, prefix, prefix_len) == 0)
	;
/*
 * We will have gone one too far in each direction.
 */
      bot++;
      top--;
/*
 * Add the completions to the list after checking them against the
 * callers requirements.
 */
      for( ; bot<=top; bot++) {
	char *match = node->files[bot];
/*
 * Form the full pathname of the file.
 */
	_pn_clear_path(pc->path);
	if(_pn_append_to_path(pc->path, node->dir, -1, 0) == NULL ||
	   _pn_append_to_path(pc->path, match+1, -1, 0) == NULL) {
	  strcpy(pc->errmsg, "Insufficient memory to complete file name");
	  return 1;
	};
/*
 * Should the file be included in the list of completions?
 */
	if(!pc->check_fn || match[0] == PCA_F_WANTED ||
	   (match[0]==PCA_F_ENIGMA && pc->check_fn(pc->data, pc->path->name))) {
	  match[0] = PCA_F_WANTED;
/*
 * Copy the completion suffix into the work pathname pc->path->name,
 * adding backslash escapes if needed.
 */
	  if(pca_prepare_suffix(pc, match + 1 + prefix_len,
				ppc->escaped))
	    return 1;
/*
 * Record the completion.
 */
	  if(cpl_add_completion(cpl, line, word_start, word_end, pc->path->name,
				"", " "))
	    return 1;
/*
 * The file was rejected by the application.
 */
	} else {
	  match[0] = PCA_F_IGNORE;
	};
      };
    };
  };
/*
 * We now need to search for subdirectories of the current directory which
 * have matching prefixes. First, if needed, make a copy of the word being
 * matched, with escapes removed.
 */
  prefix = pca_prepare_prefix(pc, start_path, prefix_len, ppc->escaped);
  if(!prefix)
    return 1;
/*
 * Now open the current directory.
 */
  if(_dr_open_dir(pc->dr, FS_PWD, NULL))
    return 0;
/*
 * Scan the current directory for sub-directories whos names start with
 * the prefix that we are completing.
 */
  while((filename = _dr_next_file(pc->dr))) {
/*
 * Does the latest filename match the prefix, and is it a directory?
 */
    if(strncmp(filename, prefix, prefix_len) == 0 && _pu_path_is_dir(filename)){
/*
 * Record the completion.
 */
      if(pca_prepare_suffix(pc, filename + prefix_len, ppc->escaped) ||
	 cpl_add_completion(cpl, line, word_start, word_end, pc->path->name,
			    FS_DIR_SEP, FS_DIR_SEP))
	return 1;
/*
 * The prefix in pc->path->name will have been overwritten by
 * pca_prepare_suffix(). Restore it here.
 */
      prefix = pca_prepare_prefix(pc, start_path, prefix_len, ppc->escaped);
      if(!prefix)
	return 1;
    };
  };
  _dr_close_dir(pc->dr);
  return 0;
}

/*.......................................................................
 * Using the work buffer pc->path, make a suitably escaped copy of a
 * given completion suffix, ready to be passed to cpl_add_completion().
 *
 * Input:
 *  pc      PathCache *  The filename cache resource object.
 *  suffix       char *  The suffix to be copied.
 *  add_escapes   int    If true, escape special characters.
 * Output:
 *  return        int    0 - OK.
 *                       1 - Error.
 */
static int pca_prepare_suffix(PathCache *pc, const char *suffix,
			      int add_escapes)
{
  const char *sptr; /* A pointer into suffix[] */
  int nbsl;         /* The number of backslashes to add to the suffix */
  int i;
/*
 * How long is the suffix?
 */
  int suffix_len = strlen(suffix);
/*
 * Clear the work buffer.
 */
  _pn_clear_path(pc->path);
/*
 * Count the number of backslashes that will have to be added to
 * escape spaces, tabs, backslashes and wildcard characters.
 */
  nbsl = 0;
  if(add_escapes) {
    for(sptr = suffix; *sptr; sptr++) {
      switch(*sptr) {
      case ' ': case '\t': case '\\': case '*': case '?': case '[':
	nbsl++;
	break;
      };
    };
  };
/*
 * Arrange for the output path buffer to have sufficient room for the
 * both the suffix and any backslashes that have to be inserted.
 */
  if(_pn_resize_path(pc->path, suffix_len + nbsl) == NULL) {
    strcpy(pc->errmsg, "Insufficient memory to complete file name");
    return 1;
  };
/*
 * If the suffix doesn't need any escapes, copy it directly into the
 * work buffer.
 */
  if(nbsl==0) {
    strcpy(pc->path->name, suffix);
  } else {
/*
 * Make a copy with special characters escaped?
 */
    if(nbsl > 0) {
      const char *src = suffix;
      char *dst = pc->path->name;
      for(i=0; i<suffix_len; i++) {
	switch(*src) {
	case ' ': case '\t': case '\\': case '*': case '?': case '[':
	  *dst++ = '\\';
	};
	*dst++ = *src++;
      };
      *dst = '\0';
    };
  };
  return 0;
}

/*.......................................................................
 * Return non-zero if the specified string appears to start with a pathname.
 *
 * Input:
 *  prefix  const char *  The filename prefix to check.
 *  prefix_len     int    The length of the prefix.
 * Output:
 *  return         int    0 - Doesn't start with a path name.
 *                        1 - Does start with a path name.
 */
static int cpa_cmd_contains_path(const char *prefix, int prefix_len)
{
  int i;
/*
 * If the filename starts with a ~, then this implies a ~username
 * expression, which constitutes a pathname.
 */
  if(*prefix == '~')
    return 1;
/*
 * If the filename starts with the root directory, then it obviously
 * starts with a pathname.
 */
  if(prefix_len >= FS_ROOT_DIR_LEN && 
     strncmp(prefix, FS_ROOT_DIR, FS_ROOT_DIR_LEN) == 0)
    return 1;
/*
 * Search the prefix for directory separators, returning as soon as
 * any are found, since their presence indicates that the filename
 * starts with a pathname specification (valid or otherwise).
 */
  for(i=0; i<prefix_len; i++) {
    if(prefix_len - i >= FS_DIR_SEP_LEN &&
       strncmp(prefix + i, FS_DIR_SEP, FS_DIR_SEP_LEN) == 0)
      return 1;
  };
/*
 * The file name doesn't appear to start with a pathname specification.
 */
  return 0;
}

/*.......................................................................
 * If needed make a new copy of the prefix being matched, in pc->path->name,
 * but with escapes removed. If no escapes are to be removed, simply return
 * the original prefix string.
 *
 * Input:
 *  pc      PathCache *   The cache being searched.
 *  prefix const char *   The prefix to be processed.
 *  prefix_len size_t     The length of the prefix.
 *  escaped       int     If true, return a copy with escapes removed.
 * Output:
 *  return const char *   The prepared prefix, or NULL on error, in
 *                        which case an error message will have been
 *                        left in pc->errmsg.
 */
static const char *pca_prepare_prefix(PathCache *pc, const char *prefix,
				      size_t prefix_len, int escaped)
{
/*
 * Make a copy with escapes removed?
 */
  if(escaped) {
    _pn_clear_path(pc->path);
    if(_pn_append_to_path(pc->path, prefix, prefix_len, 1) == NULL) {
      strcpy(pc->errmsg, "Insufficient memory to complete filename");
      return NULL;
    };
    return pc->path->name;
  };
  return prefix;
}

/*.......................................................................
 * If backslashes in the filename should be treated as literal
 * characters, call the following function with literal=1. Otherwise
 * the default is to treat them as escape characters, used for escaping
 * spaces etc..
 *
 * Input:
 *  ppc    PcaPathConf *  The pca_path_completions() configuration object
 *                        to be configured.
 *  literal        int    Pass non-zero here to enable literal interpretation
 *                        of backslashes. Pass 0 to turn off literal
 *                        interpretation.
 */
void ppc_literal_escapes(PcaPathConf *ppc, int literal)
{
  if(ppc)
    ppc->escaped = !literal;
}

/*.......................................................................
 * Call this function if you know where the index at which the
 * filename prefix starts in the input line. Otherwise by default,
 * or if you specify start_index to be -1, the filename is taken
 * to start after the first unescaped space preceding the cursor,
 * or the start of the line, which ever comes first.
 *
 * Input:
 *  ppc    PcaPathConf *  The pca_path_completions() configuration object
 *                        to be configured.
 *  start_index    int    The index of the start of the filename in
 *                        the input line, or -1 to select the default.
 */
void ppc_file_start(PcaPathConf *ppc, int start_index)
{
  if(ppc)
    ppc->file_start = start_index;
}

/*.......................................................................
 * Expand any ~user expression found at the start of a path, leaving
 * either an empty string in pc->path if there is no ~user expression,
 * or the corresponding home directory.
 *
 * Input:
 *  pc     PathCache *  The filename cache.
 *  path  const char *  The path to expand.
 *  pathlen      int    The max number of characters to look at in path[].
 *  literal      int    If true, treat backslashes as literal characters
 *                      instead of escapes.
 * Input/Output:
 *  endp  const char *  A pointer to the next unprocessed character in
 *                      path[] will be assigned to *endp.
 * Output:
 *  return       int    0 - OK
 *                      1 - Error (a description will have been placed
 *                                 in pc->errmsg[]).
 */
static int pca_expand_tilde(PathCache *pc, const char *path, int pathlen,
			    int literal, const char **endp)
{
  const char *pptr = path;  /* A pointer into path[] */
  const char *homedir=NULL; /* A home directory */
/*
 * Clear the pathname buffer.
 */
  _pn_clear_path(pc->path);
/*
 * If the first character is a tilde, then perform home-directory
 * interpolation.
 */
  if(*pptr == '~') {
/*
 * Skip the tilde character and attempt to read the username that follows
 * it, into pc->usrnam[].
 */
    if(pca_read_username(pc, ++pptr, pathlen-1, literal, &pptr))
      return 1;
/*
 * Attempt to lookup the home directory of the user.
 */
    homedir = _hd_lookup_home_dir(pc->home, pc->usrnam);
    if(!homedir) {
      strncpy(pc->errmsg, _hd_last_home_dir_error(pc->home), ERRLEN);
      pc->errmsg[ERRLEN] = '\0';
      return 1;
    };
/*
 * Append the home directory to the pathname string.
 */
    if(_pn_append_to_path(pc->path, homedir, -1, 0) == NULL) {
      strcpy(pc->errmsg, "Insufficient memory for home directory expansion");
      return 1;
    };
  };
/*
 * ~user and ~ are usually followed by a directory separator to
 * separate them from the file contained in the home directory.
 * If the home directory is the root directory, then we don't want
 * to follow the home directory by a directory separator, so we should
 * skip over it so that it doesn't get copied into the output pathname
 */
  if(homedir && strcmp(homedir, FS_ROOT_DIR) == 0 &&
     (pptr-path) + FS_DIR_SEP_LEN < pathlen &&
     strncmp(pptr, FS_DIR_SEP, FS_DIR_SEP_LEN) == 0) {
    pptr += FS_DIR_SEP_LEN;
  };
/*
 * Return a pointer to the next unprocessed character.
 */
  *endp = pptr;
  return 0;
}

/*.......................................................................
 * Clear the filename status codes that are recorded before each filename
 * in the cache.
 *
 * Input:
 *  pc     PathCache *  The filename cache.
 */
static void pca_remove_marks(PathCache *pc)
{
  PathNode *node;         /* A node in the list of directories in the path */
  int i;
/*
 * Traverse the absolute directories of the path, clearing the
 * filename status marks that precede each filename.
 */
  for(node=pc->head; node; node=node->next) {
    if(!node->relative) {
      for(i=0; i<node->nfile; i++)
	*node->files[i] = PCA_F_ENIGMA;
    };
  };
  return;
}