#!/bin/sh
#
# This script calls meld instead of ccrc_xcleardiff
# replace ccrc_xcleardiff in your <eclipse>/plugins/com.ibm.rational.clearcase.compare_merge.linux_<version> directory with this file to run meld instead
# of running the CCRC version
#

MELD=/usr/bin/meld

usage()
{
  cat 1>&2 <<EOF
USAGE

    This script is used to enhance the clearcase remote client from IBM to use
    meld for diffs and merges instead of using the clearcase merge tool.

    In order to install the application run:
        $0 --install <eclipse-install-directory>

    This will backup the original clearcase diff tool and replace it with this
    script that uses meld.

    To uninstall, use the comment
        $0 --uninstall <eclipse-install-directory>

MORE INFO

    The clearcase remote client executes the file:

        <eclipse-install-directory>/plugins/com.ibm.rational.clearcase.compare_merge.linux_*/ccrc_xcleardiff

    with various numbers of arguments to execute its diff and merge tool.

    To execute a diff, the CCRC calls ccrc_xcleardiff with various
    numbers of arguments.  When its trying to do a diff, it passes 6
    arguments:

        1  - "-fname"
        2  - The label (description) of the original file
        3  - "-fname"
        4  - the label (description) of the new file
        5  - the file with the contents of the original file
        6  - the file with the contents of the new file

    When called in merge mode, CCRC calls ccrc_xcleardiff with the
    following 12 arguments:

        1  - "-fname"
        2  - The label (description) of the base file
        3  - "-fname"
        4  - the label (description) of the first new file (new in CC)
        5  - "-fname"
        6  - the label (description) of the second new file (local file)
        7  - "-out"
        8  - The output file to save (which is the same as #12)
        9  - "-base"
        10 - the file with the contents of the base file
        11 - the file with the contents of the first new file (new in CC file)
        12 - the file with the contents of the second new file (local file)

    By calling --install on this script, the script backs up the
    original ccrc_xcleardiff for all installed ccrc plugins in the
    specified eclipse directory to ccrc_xcleardiff.orig and then makes
    link to itself as the new ccrc_xcleardiff.  Any time that the CCRC
    needs to call a merge or diff, it ends up calling this script,
    which in turn invokes meld.

    Calling --uninstall reverses this process
EOF
}

install()
{
  if [ -x "$0" ] ; then
    script="$0"
  else
    script="${PWD}/$0"
  fi

  directory="$1"
  if [ ! -d "$1" ] ; then
    echo "Can't find eclipse directory $1" 1>&2
    usage
    exit 1
  fi

  filecmd="ls ${directory}/plugins/com.ibm.rational.clearcase.compare_merge.linux_*/ccrc_xcleardiff"
  if $filecmd > /dev/null ; then
    test #noop
  else
    echo "No CCRC installations found under $1" 1>&2
    usage
    exit 1
  fi

  for file in `$filecmd` ; do
    echo "Installing to $file"
    cp $file $file.orig
    rm $file
    ln -s $script $file
  done
}

uninstall()
{
  if [ -x "$0" ] ; then
    script="$0"
  else
    script="${PWD}/$0"
  fi

  directory="$1"
  if [ ! -d "$1" ] ; then
    echo "Can't find eclipse directory $1" 1>&2
    usage
    exit 1
  fi

  filecmd="ls ${directory}/plugins/com.ibm.rational.clearcase.compare_merge.linux_*/ccrc_xcleardiff"
  if $filecmd > /dev/null ; then
    test #noop
  else
    echo "No CCRC installations found under $1" 1>&2
    usage 
    exit 1
  fi

  for file in `$filecmd` ; do
    if [ ! -x $file.orig ] ; then
      echo "Didn't find backup file $file.orig, skipping"
    else
      echo "Restoring $file"
      rm $file
      cp $file.orig $file
      rm $file.orig
    fi
  done
}

if [ "$1" = "--usage" ] ; then
  usage
  exit 0
elif [ "$1" = "--install" ] ; then
  install $2
  exit 0
elif [ "$1" = "--uninstall" ] ; then
  uninstall $2
  exit 0
elif [ "$#" = "0" ] ; then
  usage
  exit 1
fi

if [ $# = 6 ] ; then
  # 2 way
  #echo $MELD $5 --label $2 $6 --label $4 >> /tmp/ccrc_diff
  $MELD "$5" --label "$2" "$6" --label "$4" 
elif [ $# = 12 ] ; then
  #3 way
  $MELD "$10" "$8" "$11"
# $8 is the out / local
# $10 is the base
# $11 is the checked in one
else
  # use the original one, cause we have no idea what its trying to do
  $0.orig $*
fi

exit 0