# vim:ft=sh:noexpandtab
# Clever diff function

# TODO directory diff

# This function does diff and reports changes on debug level
# First and second arguments have to be paths to compared files and third argument
# have to be a debug message prepended string.
# It exits with nonzero exit code if there is no difference.
do_diff() {
	if [ ! -f "$1" ]; then
		echo_error "No reference file to compare to: $1"
		return 1 # We pretend that there is no change as reference file is missing
	fi
	if [ ! -f "$2" ]; then
		echo_dbg "$3: No target file"
		return 0
	fi

	# Do real diff if both files exists
	local DIFF="$(diff --suppress-common-lines -ay "$1" "$2")"
	if [ -n "$DIFF" ]; then
		echo_dbg "$3:
$DIFF"
	else
		return 1
	fi
}