filesys.c

gcc-2.95.3 Linux下最常用的C编译器

/* filesys.c -- File system specific functions for hacking this system.
   $Id: filesys.c,v 1.1.1.3 1998/03/24 18:20:10 law Exp $

   Copyright (C) 1993, 97, 98 Free Software Foundation, Inc.

   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 2, 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Written by Brian Fox ([e-mail]). */

#include "info.h"

#include "tilde.h"
#include "filesys.h"

/* Local to this file. */
static char *info_file_in_path (), *lookup_info_filename ();
static void remember_info_filename (), maybe_initialize_infopath ();

typedef struct
{
  char *suffix;
  char *decompressor;
} COMPRESSION_ALIST;

static char *info_suffixes[] = {
  "",
  ".info",
  "-info",
  "/index",
  (char *)NULL
};

static COMPRESSION_ALIST compress_suffixes[] = {
  { ".Z", "uncompress" },
  { ".Y", "unyabba" },
  { ".z", "gunzip" },
  { ".gz", "gunzip" },
  { (char *)NULL, (char *)NULL }
};

/* The path on which we look for info files.  You can initialize this
   from the environment variable INFOPATH if there is one, or you can
   call info_add_path () to add paths to the beginning or end of it.
   You can call zap_infopath () to make the path go away. */
char *infopath = (char *)NULL;
static int infopath_size = 0;

/* Expand the filename in PARTIAL to make a real name for this operating
   system.  This looks in INFO_PATHS in order to find the correct file.
   If it can't find the file, it returns NULL. */
static char *local_temp_filename = (char *)NULL;
static int local_temp_filename_size = 0;

char *
info_find_fullpath (partial)
     char *partial;
{
  int initial_character;
  char *temp;

  filesys_error_number = 0;

  maybe_initialize_infopath ();

  if (partial && (initial_character = *partial))
    {
      char *expansion;

      expansion = lookup_info_filename (partial);

      if (expansion)
        return (expansion);

      /* If we have the full path to this file, we still may have to add
         various extensions to it.  I guess we have to stat this file
         after all. */
      if (initial_character == '/')
        temp = info_file_in_path (partial + 1, "/");
      else if (initial_character == '~')
        {
          expansion = tilde_expand_word (partial);
          if (*expansion == '/')
            {
              temp = info_file_in_path (expansion + 1, "/");
              free (expansion);
            }
          else
            temp = expansion;
        }
      else if (initial_character == '.' &&
               (partial[1] == '/' || (partial[1] == '.' && partial[2] == '/')))
        {
          if (local_temp_filename_size < 1024)
            local_temp_filename = (char *)xrealloc
              (local_temp_filename, (local_temp_filename_size = 1024));
#if defined (HAVE_GETCWD)
          if (!getcwd (local_temp_filename, local_temp_filename_size))
#else /*  !HAVE_GETCWD */
          if (!getwd (local_temp_filename))
#endif /* !HAVE_GETCWD */
            {
              filesys_error_number = errno;
              return (partial);
            }

          strcat (local_temp_filename, "/");
          strcat (local_temp_filename, partial);
          return (local_temp_filename);
        }
      else
        temp = info_file_in_path (partial, infopath);

      if (temp)
        {
          remember_info_filename (partial, temp);
          if (strlen (temp) > local_temp_filename_size)
            local_temp_filename = (char *) xrealloc
              (local_temp_filename,
               (local_temp_filename_size = (50 + strlen (temp))));
          strcpy (local_temp_filename, temp);
          free (temp);
          return (local_temp_filename);
        }
    }
  return (partial);
}

/* Scan the list of directories in PATH looking for FILENAME.  If we find
   one that is a regular file, return it as a new string.  Otherwise, return
   a NULL pointer. */
static char *
info_file_in_path (filename, path)
     char *filename, *path;
{
  struct stat finfo;
  char *temp_dirname;
  int statable, dirname_index;

  dirname_index = 0;

  while ((temp_dirname = extract_colon_unit (path, &dirname_index)))
    {
      register int i, pre_suffix_length;
      char *temp;

      /* Expand a leading tilde if one is present. */
      if (*temp_dirname == '~')
        {
          char *expanded_dirname;

          expanded_dirname = tilde_expand_word (temp_dirname);
          free (temp_dirname);
          temp_dirname = expanded_dirname;
        }

      temp = (char *)xmalloc (30 + strlen (temp_dirname) + strlen (filename));
      strcpy (temp, temp_dirname);
      if (temp[(strlen (temp)) - 1] != '/')
        strcat (temp, "/");
      strcat (temp, filename);

      pre_suffix_length = strlen (temp);

      free (temp_dirname);

      for (i = 0; info_suffixes[i]; i++)
        {
          strcpy (temp + pre_suffix_length, info_suffixes[i]);

          statable = (stat (temp, &finfo) == 0);

          /* If we have found a regular file, then use that.  Else, if we
             have found a directory, look in that directory for this file. */
          if (statable)
            {
              if (S_ISREG (finfo.st_mode))
                {
                  return (temp);
                }
              else if (S_ISDIR (finfo.st_mode))
                {
                  char *newpath, *filename_only, *newtemp;

                  newpath = xstrdup (temp);
                  filename_only = filename_non_directory (filename);
                  newtemp = info_file_in_path (filename_only, newpath);

                  free (newpath);
                  if (newtemp)
                    {
                      free (temp);
                      return (newtemp);
                    }
                }
            }
          else
            {
              /* Add various compression suffixes to the name to see if
                 the file is present in compressed format. */
              register int j, pre_compress_suffix_length;

              pre_compress_suffix_length = strlen (temp);

              for (j = 0; compress_suffixes[j].suffix; j++)
                {
                  strcpy (temp + pre_compress_suffix_length,
                          compress_suffixes[j].suffix);

                  statable = (stat (temp, &finfo) == 0);
                  if (statable && (S_ISREG (finfo.st_mode)))
                    return (temp);
                }
            }
        }
      free (temp);
    }
  return ((char *)NULL);
}

/* Given a string containing units of information separated by colons,
   return the next one pointed to by IDX, or NULL if there are no more.
   Advance IDX to the character after the colon. */
char *
extract_colon_unit (string, idx)
     char *string;
     int *idx;
{
  register int i, start;

  i = start = *idx;
  if ((i >= strlen (string)) || !string)
    return ((char *) NULL);

  while (string[i] && string[i] != ':')
    i++;
  if (i == start)
    {
      return ((char *) NULL);
    }
  else
    {
      char *value;

      value = (char *) xmalloc (1 + (i - start));
      strncpy (value, &string[start], (i - start));
      value[i - start] = '\0';
      if (string[i])
        ++i;
      *idx = i;
      return (value);
    }
}

/* A structure which associates a filename with its expansion. */
typedef struct {
  char *filename;
  char *expansion;
} FILENAME_LIST;

/* An array of remembered arguments and results. */
static FILENAME_LIST **names_and_files = (FILENAME_LIST **)NULL;
static int names_and_files_index = 0;
static int names_and_files_slots = 0;

/* Find the result for having already called info_find_fullpath () with
   FILENAME. */
static char *
lookup_info_filename (filename)
     char *filename;
{
  if (filename && names_and_files)
    {
      register int i;
      for (i = 0; names_and_files[i]; i++)
        {
          if (strcmp (names_and_files[i]->filename, filename) == 0)
            return (names_and_files[i]->expansion);
        }
    }
  return (char *)NULL;;
}