mc/vfs/extfs/ulha.in

#! /bin/sh

#
# LHa Virtual filesystem executive v0.1
# Copyright (C) 1996, 1997 Joseph M. Hinkle
# May be distributed under the terms of the GNU Public License
# <jhinkle@rockisland.com>
#

# Code for mc_lha_fs_run() suggested by:
# Jan 97	Zdenek Kabelac <kabi@informatics.muni.cz>

# Tested with mc 3.5.18 and gawk 3.0.0 on Linux 2.0.0
# Tested with lha v1.01 and lharc v1.02
# Information and sources for other forms of lha/lzh appreciated

# Nota bene:
# There are several compression utilities which produce *.lha files.
# LHArc and LHa in exist several versions, and their listing output varies.
# Another variable is the architecture on which the compressed file was made.
# This program attempts to sort out the variables known to me, but it is likely
# to display an empty panel if it encounters a mystery. 
# In that case it will be useful to execute this file from the command line:
# ./lha list Mystery.lha
# to examine the output directly on the console.  The output string must be
# precisely in the format described in the README in this directory.
# Another helpful thing is to temporarily remove the redirection of error
# output of awk (The '2> /dev/null' instruction near the end of mcfs_list())
# The screen will get ugly if there's an error, but some useful text shows
# at the bottom of the screen.  
# Caveat emptor.
# Learn Latin.

# Define your awk
AWK=@AWK@

if ls -de . >& /dev/null;
then
    LS_COMMAND="ls -le"
else
    LS_COMMAND="ls -l --full-time"
fi

# Define which archiver you are using with appropriate options
LHA_LIST="lha l"
LHA_GET="lha pq"
LHA_PUT="lha aq"

# Define a directory to create a temporary file for when
# running a command to be run from the archive
TMPDIR=/tmp/mc-cmd.$$
# Temporary file within the directory
TMPCMD=$TMPDIR/run

# The 'list' command executive

mc_lha_fs_list()
{
   # Get the year of the file timestamp in case we need to replace 'hh:mm'
   YEAR=$($LS_COMMAND $1 | $AWK '{ print $10 }')
   # List the contents of the archive and sort it out    
   $LHA_LIST $1 | $AWK -v uid=$(id -nu) -v gid=$(id -ng) -v year=$YEAR '
      # Ignore the annotations, quit on the last one
      /^\ PERMSSN/ { next }
      /^-----/ { next }
      /^\ Total/ { exit 0 }
      # Strip a leading '/' if present in a filepath
      $(NF) ~ /^\// { $(NF) = substr($NF,2) }
      # Replace the year stamp if it is expressed as 'hh:mm'
      $(NF-1) ~ /\:/ { $(NF-1) = year }
      # Print the line this way if there is no permission string
      $1 ~ /^\[generic\]/ {
         # Invent a generic permission
         $1 = ($10 ~ /\/$/) ? "drwxr-xr-x":"-rwxr--r--";
         # Print it
         printf "%s   1 %-8s %-8s %-8d %3s %2d %4d %s\n",
                 $1,     uid, gid,  $2, $4, $5, $6, $7;
         # Get the next line of the list
         next;
      }
      # Do it this way for a defined permission
      $1 !~ /^\[generic\]/ {
         # If the permissions and UID run together
         if ($1 ~ /\//) {
            $8 = $7;
            $7 = $6;
            $6 = $5;
            $5 = $4;
            $3 = $2;
            $2 = substr($1,10);
            $1 = substr($1,1,9);
         }
         # If the permission string is missing a type
         if (length($1) == 9) {
            if ($NF ~ /\/$/)
               $1 = ("d" $1);
            else
               $1 = ("-" $1);
         }
         # UID:GID might not be the same as on your system so print numbers
         # Well, that is the intent.  At the moment mc is translating them.
         split($2, id, "/");
         printf "%s   1 %-8d %-8d %-8d %3s %2d %4d %s\n",
                 $1,     id[1], id[2],  $3, $5, $6, $7, $8;
         # Get the next line of the list
         next;
      }

   ' 2> /dev/null
}

# The 'copyout' command executive to copy displayed files to a destination

mc_lha_fs_copyout()
{
   $LHA_GET $1 $2 > $3  2> /dev/null
}

# The 'copyin' command executive to add something to the archive

mc_lha_fs_copyin ()
{
   NAME2=`basename $2`; DIR2=${2%$NAME2}
   NAME3=`basename $3`; DIR3=${3%$NAME3}

   cd ${DIR3}

   ONE2=${2%%/*}
   [ -n ${ONE2} ] || exit
   [ -e ${ONE2} ] && exit

   [ -e ${DIR2} ] || mkdir -p ${DIR2}
   ln $3 $2       || exit

   $LHA_PUT $1 $2  2> /dev/null
   rm -r ${ONE2}
}

# The 'run' command executive to run a command from within an archive

mc_lha_fs_run()
{
   trap "rm $TMPCMD; rmdir $TMPDIR; exit 0" 1 2 3 4 15
# FIXME: Try harder to generate a unique directory if this fails
   mkdir -m 0700 $TMPDIR || exit 1
   $LHA_GET $1 $2 > $TMPCMD  2> /dev/null
   chmod a+x $TMPCMD  2> /dev/null
   $TMPCMD 2> /dev/null
   rm $TMPCMD
   rmdir $TMPDIR
}


# The main routine
umask 077

case "$1" in
   list) mc_lha_fs_list $2; exit $?;;
   copyout) mc_lha_fs_copyout $2 $3 $4; exit $?;;
   copyin)  mc_lha_fs_copyin  $2 $3 $4; exit $?;;
   run)     mc_lha_fs_run     $2 $3 $4; exit $?;;
esac
exit 1