git/git-external-diff-script

#!/bin/sh
# Copyright (C) 2005 Junio C Hamano
#
# This script is designed to emulate what the built-in diff driver
# does when set as GIT_EXTERNAL_SCRIPT.

case "$#" in
1)
    echo "* Unmerged path $1"
    exit 0 ;;
*)
    name1="$1" tmp1="$2" hex1="$3" mode1="$4" tmp2="$5" hex2="$6" mode2="$7"
    case "$#" in
    7)
	name2="$name1" ;;
    9)
	name2="$8" xfrm_msg="$9" ;;
    esac ;;	
esac

show_create () {
    name_="$1" tmp_="$2" hex_="$3" mode_="$4"
    echo "diff --git a/$name_ b/$name_"
    echo "new file mode $mode_"
    diff ${GIT_DIFF_OPTS-'-pu'} -L /dev/null -L "b/$name_" /dev/null "$tmp_"
}

show_delete () {
    name_="$1" tmp_="$2" hex_="$3" mode_="$4"
    echo "diff --git a/$name_ b/$name_"
    echo "deleted file mode $mode_"
    diff ${GIT_DIFF_OPTS-'-pu'} -L "a/$name_" -L /dev/null "$tmp_" /dev/null
}

case "$mode1" in
120*) type1=l ;;
100*) type1=f ;;
.)    show_create "$name2" "$tmp2" "$hex2" "$mode2"
      exit 0 ;;
esac
case "$mode2" in
120*) type2=l ;;
100*) type2=f ;;
.)    show_delete "$name1" "$tmp1" "$hex1" "$mode1"
      exit 0 ;;
esac

if test "$type1" != "$type2"
then
	show_delete "$name1" "$tmp1" "$hex1" "$mode1"
	show_create "$name2" "$tmp2" "$hex2" "$mode2"
	exit 0
fi

echo diff --git "a/$name1" "b/$name2"
if test "$mode1" != "$mode2"
then
    echo "old mode $mode1"
    echo "new mode $mode2"
    if test "$xfrm_msg" != ""
    then
	echo -n $xfrm_msg
    fi
fi
diff ${GIT_DIFF_OPTS-'-pu'} -L "a/$name1" -L "b/$name2" "$tmp1" "$tmp2"
exit 0