configure

#!/bin/bash
#
# Configure script for RoCEHammer CMake build
#

#############################################################################
# first, initialize option parsing library
#############################################################################

third_party_root="./third-party"
shflags_src="https://shflags.googlecode.com/files/shflags-1.0.3.tgz"
shflags_root="${third_party_root}/shflags-1.0.3"

# if we don't have shflags already, get it
if [[ ! -e "${shflags_root}/src/shflags" ]]; then
    ( cd "${third_party_root}" && wget -qO- "${shflags_src}" | tar xz )
fi

# now source shflags
source "${shflags_root}/src/shflags"      

## error logging function
err() {
    echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $@" >&2
}

#############################################################################
# now, declare and parse options
#############################################################################

DEFINE_string 'gen' 'Make' 'Build tool to generate scripts for: {Make|Ninja|Xcode}. Specify multiple with commas.'

DEFINE_string 'mode' 'Release' 'Build mode: {Release|Debug}. Release includes debug symbols.'

DEFINE_string 'cc' '' 'Optional path to alternative C compiler.'

DEFINE_string 'name' '' 'Optional additional name used to distinguish this configuration (e.g. compiler version).'

DEFINE_string 'third_party' ''  'Path to optional pre-build third-party dependencies instead of re-building for each configuration.'

# parse the command line
FLAGS "$@" || exit $?
eval set -- "${FLAGS_ARGV}"

#############################################################################
# prepare to generate CMake configuration
#############################################################################

# if user specified a C compiler, find the matching C++ compiler
my_cc="${CC}"
my_cxx="${CXX}"
if [[ -n "${FLAGS_cc}" ]]; then
    my_cc="${FLAGS_cc}"
    if [[ "${FLAGS_cc}" =~ "bin/gcc" ]]; then
        my_cxx="${FLAGS_cc/gcc/g++}"
    fi    
    if [[ "${FLAGS_cc}" =~ "bin/clang" ]]; then
        my_cxx="${FLAGS_cc/clang/clang++}"
    fi
fi

# check that we have a C and C++ compiler
if [[ -z "${my_cc}" || -z "${my_cxx}" ]]; then
    err 'Error: Must specify C compiler (either use '--cc=' flag, or set the environment variables CC & CXX'
    err 'Hint: if the compiler you want is on your PATH, you can do: --cc=$(which gcc)...'
    exit 1
else
    echo "Using C compiler ${my_cc} and C++ compiler ${my_cxx}."
fi

# function to generate one configuration.
# called below for each (generator, mode) pair
configure() {
    # configure function args
    generator="$1"
    mode="$2"
    leftover="$3"

    # set generator
    case "${generator}" in
        Make)
            gen_flag="-GUnix Makefiles"
            ;;
        Xcode)
            echo "Note: '--mode' not supported for Xcode, ignoring..."
            mode=""
            gen_flag="-GXcode"
            ;;
        *)
            gen_flag="-G${generator}"
            ;;
    esac     

    # start command string
    command="cmake $(pwd)"
    
    # set C and C++ compilers
    command+=" -DCMAKE_C_COMPILER=${my_cc}"
    command+=" -DCMAKE_CXX_COMPILER=${my_cxx}"
    command+=" -DBASE_C_COMPILER=${my_cc}"
    command+=" -DBASE_CXX_COMPILER=${my_cxx}"

    # generate third-party path if necessary
    if [[ -n "${FLAGS_third_party}" ]]; then
        command+=" -DTHIRD_PARTY_ROOT:PATH=${FLAGS_third_party}"
    fi

    # translate mode if necessary
    case "${mode}" in
        Debug)   command+=" -DCMAKE_BUILD_TYPE=Debug" ;;
        Release) command+=" -DCMAKE_BUILD_TYPE=RelWithDebInfo" ;;
    esac

    # generate build directory name
    build_dir="build/${generator}"
    if [[ -n "${mode}" ]]; then
        build_dir+="+${mode}"
    fi
    if [[ -n "${FLAGS_name}" ]]; then
        build_dir+="+${FLAGS_name}"
    fi
    
    # create build directory
    ROOT_DIR="$(pwd)"
    mkdir -p "${build_dir}"
    cd "${build_dir}"
    
    # pass cmake the args we constructed, along with leftover args from original command line
    echo "${command} ${gen_flag}" ${leftover}
    if ${command} "${gen_flag}" ${leftover}; then
        echo "-------------------------------------"
        echo "created ${build_dir}; to build:"
        case "${generator}" in
            Make)  echo "> cd ${build_dir}; make -j" ;;
            Ninja) echo "> cd ${build_dir}; ninja" ;;
            Xcode) echo "> cd ${build_dir}; xcodebuild" ;;
        esac
        echo "-------------------------------------"
    fi
}

#############################################################################
# now generate CMake configurations
#############################################################################

# iterate over generator and mode settings, calling configure for each
for generator in ${FLAGS_gen/,/ }; do
    for mode in ${FLAGS_mode/,/ }; do
        configure "${generator}" "${mode}" "$@"
    done
done

echo "Done!"