source: vendor/bash/3.1/builtins/pushd.def

This file is pushd.def, from which is created pushd.c.  It implements the
builtins "pushd", "popd", and "dirs" in Bash.

Copyright (C) 1987-2004 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash 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.

Bash 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 Bash; see the file COPYING.  If not, write to the Free Software
Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.

$PRODUCES pushd.c

$BUILTIN pushd
$FUNCTION pushd_builtin
$DEPENDS_ON PUSHD_AND_POPD
$SHORT_DOC pushd [dir | +N | -N] [-n]
Adds a directory to the top of the directory stack, or rotates
the stack, making the new top of the stack the current working
directory.  With no arguments, exchanges the top two directories.

+N      Rotates the stack so that the Nth directory (counting
        from the left of the list shown by `dirs', starting with
        zero) is at the top.

-N      Rotates the stack so that the Nth directory (counting
        from the right of the list shown by `dirs', starting with
        zero) is at the top.

-n      suppress the normal change of directory when adding directories
        to the stack, so only the stack is manipulated.

dir     adds DIR to the directory stack at the top, making it the
        new current working directory.

You can see the directory stack with the `dirs' command.
$END

$BUILTIN popd
$FUNCTION popd_builtin
$DEPENDS_ON PUSHD_AND_POPD
$SHORT_DOC popd [+N | -N] [-n]
Removes entries from the directory stack.  With no arguments,
removes the top directory from the stack, and cd's to the new
top directory.

+N      removes the Nth entry counting from the left of the list
        shown by `dirs', starting with zero.  For example: `popd +0'
        removes the first directory, `popd +1' the second.

-N      removes the Nth entry counting from the right of the list
        shown by `dirs', starting with zero.  For example: `popd -0'
        removes the last directory, `popd -1' the next to last.

-n      suppress the normal change of directory when removing directories
        from the stack, so only the stack is manipulated.

You can see the directory stack with the `dirs' command.
$END

$BUILTIN dirs
$FUNCTION dirs_builtin
$DEPENDS_ON PUSHD_AND_POPD
$SHORT_DOC dirs [-clpv] [+N] [-N]
Display the list of currently remembered directories.  Directories
find their way onto the list with the `pushd' command; you can get
back up through the list with the `popd' command.

The -l flag specifies that `dirs' should not print shorthand versions
of directories which are relative to your home directory.  This means
that `~/bin' might be displayed as `/homes/bfox/bin'.  The -v flag
causes `dirs' to print the directory stack with one entry per line,
prepending the directory name with its position in the stack.  The -p
flag does the same thing, but the stack position is not prepended.
The -c flag clears the directory stack by deleting all of the elements.

+N      displays the Nth entry counting from the left of the list shown by
        dirs when invoked without options, starting with zero.

-N      displays the Nth entry counting from the right of the list shown by
        dirs when invoked without options, starting with zero.
$END

#include <config.h>

#if defined (PUSHD_AND_POPD)
#include <stdio.h>
#ifndef _MINIX
#  include <sys/param.h>
#endif

#if defined (HAVE_UNISTD_H)
#  ifdef _MINIX
#    include <sys/types.h>
#  endif
#  include <unistd.h>
#endif

#include "../bashansi.h"
#include "../bashintl.h"

#include <errno.h>

#include <tilde/tilde.h>

#include "../shell.h"
#include "maxpath.h"
#include "common.h"
#include "builtext.h"

#ifdef LOADABLE_BUILTIN
#  include "builtins.h"
#endif

#if !defined (errno)
extern int errno;
#endif /* !errno */

/* The list of remembered directories. */
static char **pushd_directory_list = (char **)NULL;

/* Number of existing slots in this list. */
static int directory_list_size;

/* Offset to the end of the list. */
static int directory_list_offset;

static void pushd_error __P((int, char *));
static void clear_directory_stack __P((void));
static int cd_to_string __P((char *));
static int change_to_temp __P((char *));
static void add_dirstack_element __P((char *));
static int get_dirstack_index __P((intmax_t, int, int *));

#define NOCD            0x01
#define ROTATE          0x02
#define LONGFORM        0x04
#define CLEARSTAK       0x08

int
pushd_builtin (list)
     WORD_LIST *list;
{
  WORD_LIST *orig_list;
  char *temp, *current_directory, *top;
  int j, flags, skipopt;
  intmax_t num;
  char direction;

  orig_list = list;
  if (list && list->word && ISOPTION (list->word->word, '-'))
    {
      list = list->next;
      skipopt = 1;
    }
  else
    skipopt = 0;

  /* If there is no argument list then switch current and
     top of list. */
  if (list == 0)
    {
      if (directory_list_offset == 0)
        {
          builtin_error (_("no other directory"));
          return (EXECUTION_FAILURE);
        }

      current_directory = get_working_directory ("pushd");
      if (current_directory == 0)
        return (EXECUTION_FAILURE);

      j = directory_list_offset - 1;
      temp = pushd_directory_list[j];
      pushd_directory_list[j] = current_directory;
      j = change_to_temp (temp);
      free (temp);
      return j;
    }

  for (flags = 0; skipopt == 0 && list; list = list->next)
    {
      if (ISOPTION (list->word->word, 'n'))
        {
          flags |= NOCD;
        }
      else if (ISOPTION (list->word->word, '-'))
        {
          list = list->next;
          break;
        }
      else if (list->word->word[0] == '-' && list->word->word[1] == '\0')
        /* Let `pushd -' work like it used to. */
        break;
      else if (((direction = list->word->word[0]) == '+') || direction == '-')
        {
          if (legal_number (list->word->word + 1, &num) == 0)
            {
              sh_invalidnum (list->word->word);
              builtin_usage ();
              return (EXECUTION_FAILURE);
            }

          if (direction == '-')
            num = directory_list_offset - num;

          if (num > directory_list_offset || num < 0)
            {
              pushd_error (directory_list_offset, list->word->word);
              return (EXECUTION_FAILURE);
            }
          flags |= ROTATE;
        }
      else if (*list->word->word == '-')
        {
          sh_invalidopt (list->word->word);
          builtin_usage ();
          return (EXECUTION_FAILURE);
        }
      else
        break;
    }

  if (flags & ROTATE)
    {
      /* Rotate the stack num times.  Remember, the current
         directory acts like it is part of the stack. */
      temp = get_working_directory ("pushd");

      if (num == 0)
        {
          j = ((flags & NOCD) == 0) ? change_to_temp (temp) : EXECUTION_SUCCESS;
          free (temp);
          return j;
        }

      do
        {
          top = pushd_directory_list[directory_list_offset - 1];

          for (j = directory_list_offset - 2; j > -1; j--)
            pushd_directory_list[j + 1] = pushd_directory_list[j];

          pushd_directory_list[j + 1] = temp;

          temp = top;
          num--;
        }
      while (num);

      j = ((flags & NOCD) == 0) ? change_to_temp (temp) : EXECUTION_SUCCESS;
      free (temp);
      return j;
    }

  if (list == 0)
    return (EXECUTION_SUCCESS);

  /* Change to the directory in list->word->word.  Save the current
     directory on the top of the stack. */
  current_directory = get_working_directory ("pushd");
  if (current_directory == 0)
    return (EXECUTION_FAILURE);

  j = ((flags & NOCD) == 0) ? cd_builtin (skipopt ? orig_list : list) : EXECUTION_SUCCESS;
  if (j == EXECUTION_SUCCESS)
    {
      add_dirstack_element ((flags & NOCD) ? savestring (list->word->word) : current_directory);
      dirs_builtin ((WORD_LIST *)NULL);
      if (flags & NOCD)
        free (current_directory);
      return (EXECUTION_SUCCESS);
    }
  else
    {
      free (current_directory);
      return (EXECUTION_FAILURE);
    }
}

/* Pop the directory stack, and then change to the new top of the stack.
   If LIST is non-null it should consist of a word +N or -N, which says
   what element to delete from the stack.  The default is the top one. */
int
popd_builtin (list)
     WORD_LIST *list;
{
  register int i;
  intmax_t which;
  int flags;
  char direction;
  char *which_word;

  which_word = (char *)NULL;
  for (flags = 0, which = 0, direction = '+'; list; list = list->next)
    {
      if (ISOPTION (list->word->word, 'n'))
        {
          flags |= NOCD;
        }
      else if (ISOPTION (list->word->word, '-'))
        {
          list = list->next;
          break;
        }
      else if (((direction = list->word->word[0]) == '+') || direction == '-')
        {
          if (legal_number (list->word->word + 1, &which) == 0)
            {
              sh_invalidnum (list->word->word);
              builtin_usage ();
              return (EXECUTION_FAILURE);
            }
          which_word = list->word->word;
        }
      else if (*list->word->word == '-')
        {
          sh_invalidopt (list->word->word);
          builtin_usage ();
          return (EXECUTION_FAILURE);
        }
      else
        break;
    }

  if (which > directory_list_offset || (directory_list_offset == 0 && which == 0))
    {
      pushd_error (directory_list_offset, which_word ? which_word : "");
      return (EXECUTION_FAILURE);
    }

  /* Handle case of no specification, or top of stack specification. */
  if ((direction == '+' && which == 0) ||
      (direction == '-' && which == directory_list_offset))
    {
      i = ((flags & NOCD) == 0) ? cd_to_string (pushd_directory_list[directory_list_offset - 1])
                                : EXECUTION_SUCCESS;
      if (i != EXECUTION_SUCCESS)
        return (i);
      free (pushd_directory_list[--directory_list_offset]);
    }
  else
    {
      /* Since an offset other than the top directory was specified,
         remove that directory from the list and shift the remainder
         of the list into place. */
      i = (direction == '+') ? directory_list_offset - which : which;
      free (pushd_directory_list[i]);
      directory_list_offset--;

      /* Shift the remainder of the list into place. */
      for (; i < directory_list_offset; i++)
        pushd_directory_list[i] = pushd_directory_list[i + 1];
    }

  dirs_builtin ((WORD_LIST *)NULL);
  return (EXECUTION_SUCCESS);
}

/* Print the current list of directories on the directory stack. */
int
dirs_builtin (list)
     WORD_LIST *list;
{
  int flags, desired_index, index_flag, vflag;
  intmax_t i;
  char *temp, *w;

  for (flags = vflag = index_flag = 0, desired_index = -1, w = ""; list; list = list->next)
    {
      if (ISOPTION (list->word->word, 'l'))
        {
          flags |= LONGFORM;
        }
      else if (ISOPTION (list->word->word, 'c'))
        {
          flags |= CLEARSTAK;
        }
      else if (ISOPTION (list->word->word, 'v'))
        {
          vflag |= 2;
        }
      else if (ISOPTION (list->word->word, 'p'))
        {
          vflag |= 1;
        }
      else if (ISOPTION (list->word->word, '-'))
        {
          list = list->next;
          break;
        }
      else if (*list->word->word == '+' || *list->word->word == '-')
        {
          int sign;
          if (legal_number (w = list->word->word + 1, &i) == 0)
            {
              sh_invalidnum (list->word->word);
              builtin_usage ();
              return (EXECUTION_FAILURE);
            }
          sign = (*list->word->word == '+') ? 1 : -1;
          desired_index = get_dirstack_index (i, sign, &index_flag);
        }
      else
        {
          sh_invalidopt (list->word->word);
          builtin_usage ();
          return (EXECUTION_FAILURE);
        }
    }

  if (flags & CLEARSTAK)
    {
      clear_directory_stack ();
      return (EXECUTION_SUCCESS);
    }

  if (index_flag && (desired_index < 0 || desired_index > directory_list_offset))
    {
      pushd_error (directory_list_offset, w);
      return (EXECUTION_FAILURE);
    }

#define DIRSTACK_FORMAT(temp) \
  (flags & LONGFORM) ? temp : polite_directory_format (temp)

  /* The first directory printed is always the current working directory. */
  if (index_flag == 0 || (index_flag == 1 && desired_index == 0))
    {
      temp = get_working_directory ("dirs");
      if (temp == 0)
        temp = savestring (_("<no current directory>"));
      if (vflag & 2)
        printf ("%2d  %s", 0, DIRSTACK_FORMAT (temp));
      else
        printf ("%s", DIRSTACK_FORMAT (temp));
      free (temp);
      if (index_flag)
        {
          putchar ('\n');
          return EXECUTION_SUCCESS;
        }
    }

#define DIRSTACK_ENTRY(i) \
  (flags & LONGFORM) ? pushd_directory_list[i] \
                     : polite_directory_format (pushd_directory_list[i])

  /* Now print the requested directory stack entries. */
  if (index_flag)
    {
      if (vflag & 2)
        printf ("%2d  %s", directory_list_offset - desired_index,
                           DIRSTACK_ENTRY (desired_index));
      else
        printf ("%s", DIRSTACK_ENTRY (desired_index));
    }
  else
    for (i = directory_list_offset - 1; i >= 0; i--)
      if (vflag >= 2)
        printf ("\n%2d  %s", directory_list_offset - (int)i, DIRSTACK_ENTRY (i));
      else
        printf ("%s%s", (vflag & 1) ? "\n" : " ", DIRSTACK_ENTRY (i));

  putchar ('\n');
  fflush (stdout);
  return (EXECUTION_SUCCESS);
}

static void
pushd_error (offset, arg)
     int offset;
     char *arg;
{
  if (offset == 0)
    builtin_error ("directory stack empty");
  else
    sh_erange (arg, "directory stack index");
}

static void
clear_directory_stack ()
{
  register int i;

  for (i = 0; i < directory_list_offset; i++)
    free (pushd_directory_list[i]);
  directory_list_offset = 0;
}

/* Switch to the directory in NAME.  This uses the cd_builtin to do the work,
   so if the result is EXECUTION_FAILURE then an error message has already
   been printed. */
static int
cd_to_string (name)
     char *name;
{
  WORD_LIST *tlist;
  WORD_LIST *dir;
  int result;

  dir = make_word_list (make_word (name), NULL);
  tlist = make_word_list (make_word ("--"), dir);
  result = cd_builtin (tlist);
  dispose_words (tlist);
  return (result);
}

static int
change_to_temp (temp)
     char *temp;
{
  int tt;

  tt = temp ? cd_to_string (temp) : EXECUTION_FAILURE;

  if (tt == EXECUTION_SUCCESS)
    dirs_builtin ((WORD_LIST *)NULL);

  return (tt);
}

static void
add_dirstack_element (dir)
     char *dir;
{
  if (directory_list_offset == directory_list_size)
    pushd_directory_list = strvec_resize (pushd_directory_list, directory_list_size += 10);
  pushd_directory_list[directory_list_offset++] = dir;
}

static int
get_dirstack_index (ind, sign, indexp)
     intmax_t ind;
     int sign, *indexp;
{
  if (indexp)
    *indexp = sign > 0 ? 1 : 2;

  /* dirs +0 prints the current working directory. */
  /* dirs -0 prints last element in directory stack */
  if (ind == 0 && sign > 0)
    return 0;
  else if (ind == directory_list_offset)
    {
      if (indexp)
        *indexp = sign > 0 ? 2 : 1;
      return 0;
    }
  else if (ind >= 0 && ind <= directory_list_offset)
    return (sign > 0 ? directory_list_offset - ind : ind);
  else
    return -1;
}

/* Used by the tilde expansion code. */
char *
get_dirstack_from_string (string)
     char *string;
{
  int ind, sign, index_flag;
  intmax_t i;

  sign = 1;
  if (*string == '-' || *string == '+')
    {
      sign = (*string == '-') ? -1 : 1;
      string++;
    }
  if (legal_number (string, &i) == 0)
    return ((char *)NULL);

  index_flag = 0;
  ind = get_dirstack_index (i, sign, &index_flag);
  if (index_flag && (ind < 0 || ind > directory_list_offset))
    return ((char *)NULL);
  if (index_flag == 0 || (index_flag == 1 && ind == 0))
    return (get_string_value ("PWD"));
  else
    return (pushd_directory_list[ind]);
}

#ifdef INCLUDE_UNUSED
char *
get_dirstack_element (ind, sign)
     intmax_t ind;
     int sign;
{
  int i;

  i = get_dirstack_index (ind, sign, (int *)NULL);
  return (i < 0 || i > directory_list_offset) ? (char *)NULL
                                              : pushd_directory_list[i];
}
#endif

void
set_dirstack_element (ind, sign, value)
     intmax_t ind;
     int  sign;
     char *value;
{
  int i;

  i = get_dirstack_index (ind, sign, (int *)NULL);
  if (ind == 0 || i < 0 || i > directory_list_offset)
    return;
  free (pushd_directory_list[i]);
  pushd_directory_list[i] = savestring (value);
}

WORD_LIST *
get_directory_stack ()
{
  register int i;
  WORD_LIST *ret;
  char *d, *t;

  for (ret = (WORD_LIST *)NULL, i = 0; i < directory_list_offset; i++)
    {
      d = polite_directory_format (pushd_directory_list[i]);
      ret = make_word_list (make_word (d), ret);
    }
  /* Now the current directory. */
  d = get_working_directory ("dirstack");
  i = 0;        /* sentinel to decide whether or not to free d */
  if (d == 0)
    d = ".";
  else
    {
      t = polite_directory_format (d);
      /* polite_directory_format sometimes returns its argument unchanged.
         If it does not, we can free d right away.  If it does, we need to
         mark d to be deleted later. */
      if (t != d)
        {
          free (d);
          d = t;
        }
      else /* t == d, so d is what we want */
        i = 1;
    }
  ret = make_word_list (make_word (d), ret);
  if (i)
    free (d);
  return ret;   /* was (REVERSE_LIST (ret, (WORD_LIST *)); */
}

#ifdef LOADABLE_BUILTIN
static char * const dirs_doc[] = {
  N_("Display the list of currently remembered directories.  Directories"),
  N_("find their way onto the list with the `pushd' command; you can get"),
  N_("back up through the list with the `popd' command."),
  N_(" "),
  N_("The -l flag specifies that `dirs' should not print shorthand versions"),
  N_("of directories which are relative to your home directory.  This means"),
  N_("that `~/bin' might be displayed as `/homes/bfox/bin'.  The -v flag"),
  N_("causes `dirs' to print the directory stack with one entry per line,"),
  N_("prepending the directory name with its position in the stack.  The -p"),
  N_("flag does the same thing, but the stack position is not prepended."),
  N_("The -c flag clears the directory stack by deleting all of the elements."),
  N_(" "),
  N_("+N   displays the Nth entry counting from the left of the list shown by"),
  N_("     dirs when invoked without options, starting with zero."),
  N_(" "),
  N_("-N   displays the Nth entry counting from the right of the list shown by"),
  N_("     dirs when invoked without options, starting with zero."),
  (char *)NULL
};

static char * const pushd_doc[] = {
  N_("Adds a directory to the top of the directory stack, or rotates"),
  N_("the stack, making the new top of the stack the current working"),
  N_("directory.  With no arguments, exchanges the top two directories."),
  N_(" "),
  N_("+N   Rotates the stack so that the Nth directory (counting"),
  N_("     from the left of the list shown by `dirs', starting with"),
  N_("     zero) is at the top."),
  N_(" "),
  N_("-N   Rotates the stack so that the Nth directory (counting"),
  N_("     from the right of the list shown by `dirs', starting with"),
  N_("     zero) is at the top."),
  N_(" "),
  N_("-n   suppress the normal change of directory when adding directories"),
  N_("     to the stack, so only the stack is manipulated."),
  N_(" "),
  N_("dir  adds DIR to the directory stack at the top, making it the"),
  N_("     new current working directory."),
  N_(" "),
  N_("You can see the directory stack with the `dirs' command."),
  (char *)NULL
};

static char * const popd_doc[] = {
  N_("Removes entries from the directory stack.  With no arguments,"),
  N_("removes the top directory from the stack, and cd's to the new"),
  N_("top directory."),
  N_(" "),
  N_("+N   removes the Nth entry counting from the left of the list"),
  N_("     shown by `dirs', starting with zero.  For example: `popd +0'"),
  N_("     removes the first directory, `popd +1' the second."),
  N_(" "),
  N_("-N   removes the Nth entry counting from the right of the list"),
  N_("     shown by `dirs', starting with zero.  For example: `popd -0'"),
  N_("     removes the last directory, `popd -1' the next to last."),
  N_(" "),
  N_("-n   suppress the normal change of directory when removing directories"),
  N_("     from the stack, so only the stack is manipulated."),
  N_(" "),
  N_("You can see the directory stack with the `dirs' command."),
  (char *)NULL
};

struct builtin pushd_struct = {
        "pushd",
        pushd_builtin,
        BUILTIN_ENABLED,
        pushd_doc,
        "pushd [+N | -N] [-n] [dir]",
        0
};

struct builtin popd_struct = {
        "popd",
        popd_builtin,
        BUILTIN_ENABLED,
        popd_doc,
        "popd [+N | -N] [-n]",
        0
};

struct builtin dirs_struct = {
        "dirs",
        dirs_builtin,
        BUILTIN_ENABLED,
        dirs_doc,
        "dirs [-clpv] [+N] [-N]",
        0
};
#endif /* LOADABLE_BUILTIN */

#endif /* PUSHD_AND_POPD */