#!/bin/zsh
#======================================================================================
#         FILE: cp_if_different.sh
#
#        USAGE: cp_if_different.sh source_file target_file
#
#  DESCRIPTION: Copies the contents of the source_file to the target_file 
#               if target_file content is different then source_file content.
#               Useful for copying autogenerated Swift files to avoid 
#               recompilations due to changes of file's modification date.
#======================================================================================


SOURCE_LOCATION=$1
DESTINATION_LOCATION=$2

if test -f $DESTINATION_LOCATION; then
    if cmp --silent $SOURCE_LOCATION $DESTINATION_LOCATION; then
        # files are identical
        exit 0
    else
        # files are different
        rm $DESTINATION_LOCATION
    fi
fi

cp $SOURCE_LOCATION $DESTINATION_LOCATION