#!/bin/bash

# flxfix 0.2 - 2005/04/17 - Willy Tarreau <willy@ant-computing.com>
# Generates a shell script from a difference between two trees so that the last
# one becomes as close to the first one as possible. Second usage is to rebuild
# all the meta-data from a signature.
#
# usage:
#   flx check <reference> <tobefixed> | flxfix [ -R ] > fix.sh
#       Use -R to swap the two trees
#   flx sign <reference> | flxfix -n > create.sh
#       Generates a shell script which rebuilds the meta-data from the tree's
#       signature.
#
# WARNING: this script does not understand flx-0.7's extended encoding of
#          unprintable characters.


entryisdiff=1
restoredate=1
unset mustswap ignoreuid

# usage : fixperms $perm $uid $gid $date $name
function fixperms {
   echo touch ${restoredate:+-t \"$(date -d "Jan 1 00:00:$4 UTC 1970" +"%Y%m%d%H%M.%S" )\"} $5
   [ -z "$ignoreuid" ] && echo chown $2:$3 $5
   echo chmod $1 $5
}

# swap diff direction : -/+, </>
function swap {
   local x
   x=${1/</.}; x=${x/>/<}; x=${x/./>}
   x=${x/-/.}; x=${x/+/-}; x=${x/./+}
   echo -n $x
}

# usage: usage progname exitcode
function usage {
   echo "$1: Generates a script to rebuild the meta-data from an flx signature"
   echo "Usage:"
   echo "    flx check <reference> <tobefixed> | $1 > fix.sh"
   echo "    flx check <tobefixed> <reference> | $1 -R > fix.sh"
   echo "    flx sign  <reference> | $1 -n > new.sh"
   echo "    cat old-signature.lst | $1 -n > new.sh"
   echo ""
   echo "Options:"
   echo "    -R    swap the two trees"
   echo "    -n    recreate a new tree from a single signature"
   echo "    -t    do not restore timestamp"
   echo "    -u    do not restore uid/gid"

   exit $2
}


while [ $# -gt 0 ]; do
  if [ "x$1" = "x-R" ]; then
     mustswap=1
  elif [ "x$1" = "x-n" ]; then
     unset entryisdiff
  elif [ "x$1" = "x-u" ]; then
     ignoreuid=1
  elif [ "x$1" = "x-t" ]; then
     unset restoredate
  elif [ "x$1" = "x-h" ]; then
     usage "${0##*/}" 0
  else
     echo "Warning: ignoring unknown option: $1"
     usage "${0##*/}" 1
  fi
  shift
done

# trick: we only reference the 'chg' variable if 'entryisdiff' is set.
while read ${entryisdiff:+chg} type perm uid gid size sign date name link rest; do
   if [ -z "$entryisdiff" ]; then
      chg='-'
   elif [ -n "$mustswap" ]; then
      chg=$(swap $chg)
   fi

   if [ "x$rest" != "x" -o "x$type" != "xl" -a "x$link" != "x" ]; then
	echo "# Ignoring too long line : $REPLY"
	continue
   elif [ "x$name" = "x" -o "x$type" = "xl" -a "x$link" = "x" ]; then
	echo "# Ignoring too short line : $REPLY"
	continue
   fi

   if [ x$chg = x+ ]; then
      # new entry which wasn't in <reference>, should be removed
      if [ x$type = xd ]; then
         # theorically, we should use rm -rf to suppress all children
         echo rmdir $name
      else
         echo rm -f $name
      fi
   elif [ x$chg = x- ]; then
      # missing entry, sometimes we can rebuild them
      if [ x$type = xl ]; then
         # we'll rebuild a symbolic link
         echo ln -s $link $name
         [ -z "$ignoreuid" ] && echo chown -h $uid:$gid $name
      elif [ x$type = xd ]; then
         # we'll rebuild a directory
         echo mkdir -p $name
         fixperms $perm $uid $gid $date $name
      elif [ x$type = x- ]; then
         if [ x$size = x0 ]; then
            # we can also rebuild files, only if they are empty
            fixperms $perm $uid $gid $date $name
         else
            echo "echo \"Cannot create missing file $name ($size bytes).\""
         fi
      elif [ x$type = xc -o x$type = xb -o x$type = xf ]; then
         # we'll rebuild nodes
         echo mknod $name ${type/f/p} ${size/,/ }
         fixperms $perm $uid $gid $date $name
      else
         echo "echo \"Cannot fix $name, unsupported file type : $type\""
      fi
   elif [ x$chg = x\< ]; then
      # entry has changed
      if [ x$type = xl ]; then
         # we'll destroy and rebuild a symbolic link
         echo rm -f $name
         echo ln -s $link $name
         [ -z "$ignoreuid" ] && echo chown -h $uid:$gid $name
      elif [ x$type = xc -o x$type = xb -o x$type = xf ]; then
         # we'll destroy and rebuild nodes
         echo rm -f $name
         echo mknod $name ${type/f/p} ${size/,/ }
         fixperms $perm $uid $gid $date $name
      else
         # in other cases, we only try to fix perms
         fixperms $perm $uid $gid $date $name
      fi
   fi
done