/* $Id: thunar-vfs-util.c 28908 2008-11-25 18:55:43Z nick $ */
/*-
 * Copyright (c) 2005-2006 Benedikt Meurer <benny@xfce.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * thunar_vfs_canonicalize_pathname() derived from code by Brian Fox and Chet
 * Ramey in GNU Bash, the Bourne Again SHell.  Copyright (C) 1987, 1988, 1989,
 * 1990, 1991, 1992 Free Software Foundation, Inc.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include <thunar-vfs/thunar-vfs-util.h>
#include <thunar-vfs/thunar-vfs-alias.h>



static inline gint
find_next_slash (const gchar *path,
                 gint         current_offset)
{
	const gchar *match;
	match = strchr (path + current_offset, G_DIR_SEPARATOR);
	return (match == NULL) ? -1 : (match - path);
}



static inline gint
find_slash_before_offset (const gchar *path,
                          gint         to)
{
	gint next_offset;
	gint result = -1;

	for (next_offset = 0;; ++next_offset)
    {
		  next_offset = find_next_slash (path, next_offset);
  		if (next_offset < 0 || next_offset >= to)
	  		break;

      result = next_offset;
	  }

	return result;
}



static inline void
collapse_slash_runs (gchar *path,
                     gint   from_offset)
{
	gint i;

	/* Collapse multiple `/'s in a row. */
	for (i = from_offset; path[i] == G_DIR_SEPARATOR; i++)
    ;

	if (from_offset < i)
		memmove (path + from_offset, path + i, strlen (path + i) + 1);
}



/**
 * thunar_vfs_canonicalize_filename:
 * @filename : a local filename.
 *
 * Canonicalizes @filename and returns a new path. The new path
 * differs from @filename in:
 *
 * <simplelist>
 * <member>Multiple `/'s are collapsed to a single `/'.</member>
 * <member>Leading `./'s and trailing `/.'s are removed.</member>
 * <member>Non-leading `../'s and trailing `..'s are handled by removing portions of the path.</member>
 * </simplelist>
 *
 * The caller is responsible to free the returned string using
 * g_free() when no longer needed.
 *
 * Return value: the canonicalized path for @filename.
 **/
gchar*
thunar_vfs_canonicalize_filename (const gchar *filename)
{
  gchar *path;
  gint   marker;
  gint   i;

  g_return_val_if_fail (filename != NULL, NULL);

  /* take a copy of the filename to operate on */
  path = g_strdup (filename);
	if (G_UNLIKELY (*path == '\0'))
    return path;

	/* Walk along path looking for things to compact. */
	for (i = 0, marker = 0;;)
    {
  		if (G_UNLIKELY (path[i] == '\0'))
	  		break;

      /* Check for `../', `./' or trailing `.' by itself. */
      if (path[i] == '.')
        {
          /* Handle trailing `.' by itself. */
          if (path[i + 1] == '\0')
            {
              if (i > 1 && path[i - 1] == G_DIR_SEPARATOR)
                {
                  /* strip the trailing /. */
                  path[i - 1] = '\0';
                }
              else
                {
                  /* convert path "/." to "/" */
                  path[i] = '\0';
                }
              break;
            }

          /* Handle `./'. */
          if (path[i + 1] == G_DIR_SEPARATOR)
            {
              memmove (path + i, path + i + 2, strlen (path + i + 2) + 1);
              if (i == 0)
                {
                  /* don't leave leading '/' for paths that started
                   * as relative (.//foo)
                   */
                  collapse_slash_runs (path, i);
                  marker = 0;
                }
              continue;
            }

          /* Handle `../' or trailing `..' by itself. 
           * Remove the previous xxx/ part 
           */
          if (path[i + 1] == '.' && (path[i + 2] == G_DIR_SEPARATOR || path[i + 2] == '\0'))
            {
              /* ignore ../ at the beginning of a path */
              if (i != 0)
                {
                  marker = find_slash_before_offset (path, i - 1);

                  /* Either advance past '/' or point to the first character */
                  marker ++;
                  if (path [i + 2] == '\0' && marker > 1)
                    {
                      /* If we are looking at a /.. at the end of the uri and we
                       * need to eat the last '/' too.
                       */
                       marker--;
                    }
                  
                  /* strip the entire ../ string */
                  if (path[i + 2] == G_DIR_SEPARATOR)
                    ++i;

                  memmove (path + marker, path + i + 2, strlen (path + i + 2) + 1);
                  i = marker;
                }
              else
                {
                  i = 2;
                  if (path[i] == G_DIR_SEPARATOR)
                    i++;
                }
              
              collapse_slash_runs (path, i);
              continue;
            }
        }
      
      /* advance to the next '/' */
      i = find_next_slash (path, i);

      /* If we didn't find any slashes, then there is nothing left to do. */
      if (i < 0)
        break;

      marker = i++;
      collapse_slash_runs (path, i);
    }

	return path;
}



/**
 * thunar_vfs_expand_filename:
 * @filename : a local filename.
 * @error    : return location for errors or %NULL.
 *
 * Takes a user-typed @filename and expands a tilde at the
 * beginning of the @filename.
 *
 * The caller is responsible to free the returned string using
 * g_free() when no longer needed.
 *
 * Return value: the expanded @filename or %NULL on error.
 **/
gchar*
thunar_vfs_expand_filename (const gchar *filename,
                            GError     **error)
{
  struct passwd *passwd;
  const gchar   *replacement;
  const gchar   *remainder;
  const gchar   *slash;
  gchar         *username;

  g_return_val_if_fail (filename != NULL, NULL);

  /* check if we have a valid (non-empty!) filename */
  if (G_UNLIKELY (*filename == '\0'))
    {
      g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_INVAL, _("Invalid path"));
      return NULL;
    }

  /* check if we start with a '~' */
  if (G_LIKELY (*filename != '~'))
    return g_strdup (filename);

  /* examine the remainder of the filename */
  remainder = filename + 1;

  /* if we have only the slash, then we want the home dir */
  if (G_UNLIKELY (*remainder == '\0'))
    return g_strdup (xfce_get_homedir ());

  /* lookup the slash */
  for (slash = remainder; *slash != '\0' && *slash != G_DIR_SEPARATOR; ++slash)
    ;

  /* check if a username was given after the '~' */
  if (G_LIKELY (slash == remainder))
    {
      /* replace the tilde with the home dir */
      replacement = xfce_get_homedir ();
    }
  else
    {
      /* lookup the pwd entry for the username */
      username = g_strndup (remainder, slash - remainder);
      passwd = getpwnam (username);
      g_free (username);

      /* check if we have a valid entry */
      if (G_UNLIKELY (passwd == NULL))
        {
          username = g_strndup (remainder, slash - remainder);
          g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_INVAL, _("Unknown user \"%s\""), username);
          g_free (username);
          return NULL;
        }

      /* use the homedir of the specified user */
      replacement = passwd->pw_dir;
    }

  /* generate the filename */
  return g_build_filename (replacement, slash, NULL);
}



/**
 * thunar_vfs_humanize_size:
 * @size   : size in bytes.
 * @buffer : destination buffer or %NULL to dynamically allocate a buffer.
 * @buflen : length of @buffer in bytes.
 *
 * The caller is responsible to free the returned string using g_free()
 * if you pass %NULL for @buffer. Else the returned string will be a
 * pointer to @buffer.
 *
 * Return value: a string containing a human readable description of @size.
 **/
gchar*
thunar_vfs_humanize_size (ThunarVfsFileSize size,
                          gchar            *buffer,
                          gsize             buflen)
{
  /* allocate buffer if necessary */
  if (buffer == NULL)
    {
      buffer = g_new (gchar, 32);
      buflen = 32;
    }

  if (G_UNLIKELY (size > 1024ul * 1024ul * 1024ul))
    g_snprintf (buffer, buflen, "%0.1f GB", size / (1024.0 * 1024.0 * 1024.0));
  else if (size > 1024ul * 1024ul)
    g_snprintf (buffer, buflen, "%0.1f MB", size / (1024.0 * 1024.0));
  else if (size > 1024ul)
    g_snprintf (buffer, buflen, "%0.1f kB", size / 1024.0);
  else
    g_snprintf (buffer, buflen, "%lu B", (gulong) size);

  return buffer;
}



#define __THUNAR_VFS_UTIL_C__
#include <thunar-vfs/thunar-vfs-aliasdef.c>
