configure

#!/bin/sh
#
# Copyright (c) Brian Koropoff
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the MakeKit project nor the names of its
#       contributors may be used to endorse or promote products derived
#       from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
# THE POSSIBILITY OF SUCH DAMAGE.
#

##
#
# makekit -- main script
#
# This script is merely a wrapper over the individual commands
# in the mk/command subdirectory.  Its job is to:
# 
# - Find the mk directory
# - Set MK_SHELL to a fast, POSIX-compliant shell
# - Set PATH to include POSIX-compliant utilities
# - Run the actual command
##

MK_DEFAULT_HOME="@MK_DEFAULT_HOME@"
MK_SOURCE_DIR="`dirname "$0"`"
MK_COMMAND="`basename "$0"`"

fail()
{
    echo "error: $1"
    exit 1
}

find_shell()
{
    if test "`uname`" = "FreeBSD"
    then
        # Look for dash in the path
        # /bin/sh is an ancestor of dash on FreeBSD, so
        # fall back on it and don't bother with bash
        SHELL_CANDIDATES="dash"
        SHELL_FALLBACKS="/bin/sh"
    else
        # Look for dash or bash in the path
        # Fall back on xpg4 sh (Solaris) or /bin/sh
        SHELL_CANDIDATES="dash bash"
        SHELL_FALLBACKS="/usr/xpg4/bin/sh /bin/sh"
    fi

    if test "x$MK_SHELL" != "x"
    then
        return 0
    fi

    if type mkdash >/dev/null 2>&1
    then
        MK_SHELL=mkdash
        return 0
    fi

    if test -x "${HOME}/.makekit/mkdash"
    then
        MK_SHELL="${HOME}/.makekit/mkdash"
        return 0
    fi

    if test -f "$MK_HOME/mkdash.c"
    then
        if type clang >/dev/null 2>&1
        then
            _CC=clang
        elif type gcc >/dev/null 2>&1
        then
            _CC=gcc
        else
            _CC=cc
        fi

        echo "           [makekit] building ${HOME}/.makekit/mkdash" >/dev/tty
        mkdir -p "${HOME}/.makekit" >/dev/null 2>&1
        if "$_CC" -O2 -o "${HOME}/.makekit/mkdash" "$MK_HOME/mkdash.c" >/dev/null 2>&1
        then
            MK_SHELL="${HOME}/.makekit/mkdash"
            return 0
        fi
        echo "           [makekit] falling back on existing shell" >/dev/tty
    fi

    for _shell in ${SHELL_CANDIDATES}
    do
        _IFS="$IFS"
        IFS=":"
        for _dir in ${PATH}
        do
            if [ -x "$_dir/$_shell" ]
            then
                MK_SHELL="$_dir/$_shell"
                return 0
            fi
        done
        IFS="$_IFS"
    done
    
    for _shell in ${SHELL_FALLBACKS}
    do
        if [ -x "$_shell" ]
        then
            MK_SHELL="$_shell"
            return 0
        fi
    done

    return 1
}

if test -d "$MK_HOME"
then
    :
elif test -d "$MK_DEFAULT_HOME"
then
    MK_HOME="${MK_DEFAULT_HOME}"
elif test -d "${MK_SOURCE_DIR}/mk"
then
    MK_HOME="${MK_SOURCE_DIR}/mk"
elif test -x "${MK_SOURCE_DIR}/makekit"
then
    MK_HOME="${MK_SOURCE_DIR}"
else
    echo "ERROR: could not find valid MK_HOME"
    exit 1
fi

# If the system has /usr/xpg4/bin, add it to the path
# so we get POSIX-compliant utilities
if test -d "/usr/xpg4/bin"
then
    PATH="/usr/xpg4/bin:$PATH"
fi

if test -n "$MK_TRACE"
then
    _trace="-x"
fi

if test x"$MK_COMMAND" = x"makekit"
then
    MK_COMMAND="$1"
    shift
fi

# Find a shell
find_shell || fail "could not find a usable shell"

export MK_HOME MK_SHELL MK_SOURCE_DIR PATH

if test -f "${MK_HOME}/command/${MK_COMMAND}.sh"
then
    exec $MK_SHELL ${_trace} "${MK_HOME}/command/${MK_COMMAND}.sh" "$@"
else
    echo "Unknown command: $MK_COMMAND"
    exit 1
fi