#!/bin/bash
#
# $Id: safedir,v 1.6 2005/02/01 23:47:34 jpeek Exp $
#
# safedir - make a temporary directory populated with sanely-named
#     symlinks to entries in another directory remdir.  Outputs name
#     of temporary directory, or /CANNOT-MAKE-DIRECTORY-* on error.
#     Makes filename translation table in destination directory.
#
# Usage:  safedir remdir
# or:     cd `safedir remdir`
#
# NO WARRANTY.  YOU'RE RESPONSIBLE TO DECIDE IF THIS MEETS YOUR NEEDS.
#
# Placed in the public domain by Jerry Peek.  If you make changes or
# have suggestions, please tell me; see www.jpeek.com/contact.html.

myname="${0##*/}"                      # name of this script
destdir="/tmp/SAFEDIR-$USER-$$"        # where we make the symlinks
usage="Usage: ${0##*/} remote-directory"
srcdir="$1"                            # directory we make links to
ttable=.safedir_translation_table      # holds new<TAB>old filenames
pwdcmd=/bin/pwd                        # gets hard path to current dir
fix=_                                  # replace $xlate with this
# Characters to replace with $fix.
# Note embedded single quote and the space, tab and newline at end:
xlate='=!#$%^&*()|\\'"'"';/<>?~`[]{} 	
'

giveup()
{
  # Output a bogus directory name so "cd 'safedir'" will fail:
  echo "DID-NOT-MAKE-DIRECTORY-$destdir"
  exit 1
}

if [ ! -d "$srcdir" -o $# -ne 1 ]
then
  echo "$myname: $srcdir isn't a directory, or command line has error." 1>&2
  echo "$usage" 1>&2
  giveup
fi

# Change current directory to $srcdir, directory to which we make links.
# Get absolute pathname of this directory with symlinks resolved:
if ! cd "$srcdir"
then
  echo "$myname: can't change to directory '$srcdir'" 1>&2
  echo "$usage" 1>&2
  giveup
else
  curdir=$($pwdcmd)
fi

# Be sure current directory is readable ([ -r ] doesn't seem to work)
lsout=$(/bin/ls)
if [ $? -ne 0 -o -z "$lsout" ]
then
  echo "$myname: can't list directory '$srcdir'?" 1>&2
  giveup
fi

# Be sure we won't clobber an existing translation table file:
if [ -e $ttable ]
then
  echo "$myname: aborting: $ttable exists in $srcdir,
    so copy I generate in $destdir might be incorrect." 1>&2
  giveup
fi

if mkdir "$destdir"
then
  chmod 700 "$destdir" || giveup
else
  echo "$myname: can't create temporary directory $destdir" 1>&2
  giveup
fi

# Loop through current directory and make symlinks in $destdir.
# NOTE that standard output of loop is redirected to $ttable file;
# this collects standard output from the "echo -E" command:
for f in *
do
  fnew=$(echo -E -n "$f" | tr "$xlate" "[${fix}*]")  # new filename

  if [ -d "$f" ]
  then
    echo "$myname: caution: $f ($fnew) is a subdirectory.
      cd'ing through it will take you to non-converted filenames" 1>&2
  fi

  # Be sure some earlier name wasn't already converted to $fnew.
  # We could do some fancy renaming, but we simply punt:
  if [ -L "$destdir/$fnew" ]
  then
    echo "$myname: WARNING: not linking to $f because safe-named
      $fnew already exists in $destdir.  Continuing..." 1>&2
  else
    if ln -s "$curdir/$f" "$destdir/$fnew"
    then
      # Write to stdout, redirected at end of loop to $ttable file.
      # This string has an embedded TAB (we can't use \t because
      # "echo -e" could mistakenly interpret an escape sequence in $f):
      echo -E "$fnew	$f"
    else
      echo "$myname: ABORTING: can't create symlink $destdir/$fnew?" 1>&2
      giveup
    fi
  fi
done > "$destdir/$ttable"

# Output links-directory name ("cd 'safedir'" will work if it's used):
echo "$destdir"
exit 0