source: MondoRescue/branches/3.2/mindi-busybox/scripts/gen_build_files.sh

#!/bin/sh

# Note: was using sed OPTS CMD -- FILES
# but users complain that many sed implementations
# are misinterpreting --.

test $# -ge 2 || { echo "Syntax: $0 SRCTREE OBJTREE"; exit 1; }

# cd to objtree
cd -- "$2" || { echo "Syntax: $0 SRCTREE OBJTREE"; exit 1; }
# In separate objtree build, include/ might not exist yet
mkdir include 2>/dev/null

srctree="$1"

status() { printf '  %-8s%s\n' "$1" "$2"; }
gen() { status "GEN" "$@"; }
chk() { status "CHK" "$@"; }

generate()
{
    # NB: data to be inserted at INSERT line is coming on stdin
    local src="$1" dst="$2" header="$3"
    #chk "${dst}"
    {
        # Need to use printf: different shells have inconsistent
        # rules re handling of "\n" in echo params.
        printf "%s\n" "${header}"
        # print everything up to INSERT line
        sed -n '/^INSERT$/ q; p' "${src}"
        # copy stdin to stdout
        cat
        # print everything after INSERT line
        sed -n '/^INSERT$/ { :l; n; p; bl }' "${src}"
    } >"${dst}.tmp"
    if ! cmp -s "${dst}" "${dst}.tmp"; then
        gen "${dst}"
        mv "${dst}.tmp" "${dst}"
    else
        rm -f "${dst}.tmp"
    fi
}

# (Re)generate include/applets.h
sed -n 's@^//applet:@@p' "$srctree"/*/*.c "$srctree"/*/*/*.c \
| generate \
    "$srctree/include/applets.src.h" \
    "include/applets.h" \
    "/* DO NOT EDIT. This file is generated from applets.src.h */"

# (Re)generate include/usage.h
# We add line continuation backslash after each line,
# and insert empty line before each line which doesn't start
# with space or tab
sed -n -e 's@^//usage:\([ \t].*\)$@\1 \\@p' -e 's@^//usage:\([^ \t].*\)$@\n\1 \\@p' \
    "$srctree"/*/*.c "$srctree"/*/*/*.c \
| generate \
    "$srctree/include/usage.src.h" \
    "include/usage.h" \
    "/* DO NOT EDIT. This file is generated from usage.src.h */"

# (Re)generate */Kbuild and */Config.in
# We skip .dotdirs - makes git/svn/etc users happier
{ cd -- "$srctree" && find . -type d -not '(' -name '.?*' -prune ')'; } \
| while read -r d; do
    d="${d#./}"

    src="$srctree/$d/Kbuild.src"
    dst="$d/Kbuild"
    if test -f "$src"; then
        mkdir -p -- "$d" 2>/dev/null

        sed -n 's@^//kbuild:@@p' "$srctree/$d"/*.c \
        | generate \
            "${src}" "${dst}" \
            "# DO NOT EDIT. This file is generated from Kbuild.src"
    fi

    src="$srctree/$d/Config.src"
    dst="$d/Config.in"
    if test -f "$src"; then
        mkdir -p -- "$d" 2>/dev/null

        sed -n 's@^//config:@@p' "$srctree/$d"/*.c \
        | generate \
            "${src}" "${dst}" \
            "# DO NOT EDIT. This file is generated from Config.src"
    fi
done

# Last read failed. This is normal. Don't exit with its error code:
exit 0