#!/bin/sh

#
# feature-check: This script looks for feature statements in a file by
# executing a compiler under CPP and extracting lines of the following
# form:
#
# netsnmp_feature_provides(foo): used to indicate it provides feature "foo"
# netsnmp_feature_require(bar): used to indicate it requires feature "bar"
# netsnmp_feature_want(bar): used to indicate it wants feature "bar"
#                    (but can live without it)
#
# Using these lines it then generates a list of feature requirement
# defines in "include/net-snmp/net-snmp-features.h" which can then be
# loaded in later passes at compile time.
#
# Defines produced when netsnmp_featre_require(bar) is present:
#   #define NETSNMP_FEATURE_REQUIRE_BAR 1
#
# Defines produced when netsnmp_feature_want(bar) is present:
#   #define NETSNMP_FEATURE_WANT_BAR 1
#
# And when all the features have been collected, they are also inverted via
# the feature-post-check script:
#
#   #define NETSNMP_FEATURE_REMOVE_BARX 1  /* never required */
#   #undef  NETSNMP_FEATURE_REMOVE_BAR      /* required */

# Usage:

# feature-check NORMAL-COMPILE-LINE

SED=sed
GREP=grep
CC=gcc
RM=rm

if test "x$1" = "x--feature-global" ; then
    # a global file should be included
    shift
    global=$1
    shift
fi

sourcedir=$1
shift

source=$1
shift

destination=$1
shift

tmpf="$destination.1"

compileline="$@"
$compileline '-DNETSNMP_FEATURE_CHECKING=1' \
             '-DNETSNMP_MINIMAL_CODE=1' \
             '-Dnetsnmp_feature_require(X)=X NSF_RR' \
             '-Dnetsnmp_feature_provide(X)=X NSF_PP' \
             '-Dnetsnmp_feature_child_of(X,Y)=X,Y NSF_CO' \
             '-Dnetsnmp_feature_want(X)=X NSF_WW' $source | \
    $GREP NSF_ | $GREP -v '^#define' > $tmpf

$RM -f $destination;
touch $destination;

# process requires
firstrequire=1
for i in `grep NSF_RR $tmpf | sed 's/ NSF_RR//'` ; do
    if test $firstrequire = 1 ; then
	echo "" >> $destination
	echo "/* required by $sourcedir/$source */" >> $destination
	firstrequire=0
    fi
    upper=`echo $i | tr a-z A-Z`
    echo "#define NETSNMP_FEATURE_REQUIRE_$upper 1" >> $destination
done

# process provides
firstfeature=1
for i in `grep NSF_PP $tmpf | sed 's/ NSF_PP//'` ; do
    if test $firstfeature = 1 ; then
	echo "" >> $destination
	echo "/* features provided by $sourcedir/$source */" >> $destination
	firstfeature=0
    fi
    upper=`echo $i | tr a-z A-Z`
    echo "#define NETSNMP_FEATURE_PROVIDE_$upper 1" >> $destination
done

# process children
firstfeature=1
for i in `grep NSF_CO $tmpf | sed 's/ NSF_CO//'` ; do
    parent=`echo $i | sed 's/.*,//'`
    child=`echo $i | sed 's/,.*//'`
    if test $firstfeature = 1 ; then
	echo "" >> $destination
	echo "/* features provided by $sourcedir/$source */" >> $destination
	firstfeature=0
    fi
    upperchild=`echo $child | tr a-z A-Z`
    upperparent=`echo $parent | tr a-z A-Z`
    echo "#define NETSNMP_FEATURE_${upperchild}_CHILD_OF_${upperparent} 1" >> $destination
    echo "#define NETSNMP_FEATURE_PROVIDE_$upperchild 1" >> $destination
done

# process wants
firstfeature=1
for i in `grep NSF_WW $tmpf | sed 's/ NSF_WW//'` ; do
    if test $firstfeature = 1 ; then
	echo "" >> $destination
	echo "/* features wanted by $sourcedir/$source */" >> $destination
	firstfeature=0
    fi
    upper=`echo $i | tr a-z A-Z`
    echo "#define NETSNMP_FEATURE_WANT_$upper 1" >> $destination
done

if test "x$global" != "x" ; then
    cat $destination >> $global
fi


# clean up
#$RM -f $tmpf