#!/bin/bash
#
# pbuilder hook script: choose optional compiler rather than default one
#
# Sometimes we want to choose other compiler than default, because of improving
# code to conform to standard, check compiler quality or so. This script will
# ease it. Try enable hook script and set "CHOOSE_COMPILER" variables as clang,
# gcc-*, or other compilers (note: however, now only clang and gcc can works
# well and others fails to build).
#
# i.e.)
#  $ sudo CHOOSE_COMPILER="clang" pbuilder --build foobar_1.0-1.dsc
#  $ sudo CHOOSE_COMPILER="gcc-4.6" pbuilder --build foobar_1.0-1.dsc
#

set -e

# check whether we are asked to change the compiler.
case "${CHOOSE_COMPILER}" in
    clang)
        newcc=/usr/bin/"${CHOOSE_COMPILER}"
        newcxx=/usr/bin/"${CHOOSE_COMPILER}"++
        ;;
    clang-*)
        use_clang_version=${CHOOSE_COMPILER#clang-}
        clang_package=clang-"${use_clang_version}"
        newcc=/usr/bin/clang-"${use_clang_version}"
        newcxx=/usr/bin/clang++-"${use_clang_version}"
        ;;
    gcc-*)
        use_gcc_version=${CHOOSE_COMPILER#gcc-}
        gxx_package=g++-"${use_gcc_version}"
        newcc=/usr/bin/"${CHOOSE_COMPILER}"
        newcxx=/usr/bin/g++-"${use_gcc_version}"
        ;;
    tcc)
        newcc=/usr/bin/"${CHOOSE_COMPILER}"
        newcxx=/bin/false
        not_gcc_compat=1
        ;;
    pcc)
        newcc=/usr/bin/"${CHOOSE_COMPILER}"
        newcxx=/bin/false
        not_gcc_compat=1
        ;;
    *)
        exit 0
        ;;
esac

apt-get install -y "${APTGETOPT[@]}" "${CHOOSE_COMPILER}" "${gxx_package}" "${clang_package}"

if [ ! -x /usr/bin/"${CHOOSE_COMPILER}" ]; then
    echo >&2 "E: Package ${CHOOSE_COMPILER} does not contain compiler driver?"
    exit 1
fi

ln -sf "${newcc}" /usr/bin/cc
ln -sf "${newcxx}" /usr/bin/c++

if [ -z "${not_gcc_compat}" ]; then
    (
    cd /usr/bin
    ln -sf "$newcc" gcc
    ln -sf "$newcxx" g++
    )
else
    rm -f /usr/bin/gcc /usr/bin/g++
fi

exit 0
