+dnl OVS_FIND_FIELD_IFELSE(FILE, STRUCTURE, REGEX, [IF-MATCH], [IF-NO-MATCH])
+dnl
+dnl Looks for STRUCTURE in FILE. If it is found, greps for REGEX within the
+dnl structure definition. If this is successful, runs IF-MATCH, otherwise
+dnl IF_NO_MATCH. If IF-MATCH is empty then it defines to
+dnl OVS_DEFINE(HAVE_<STRUCTURE>_WITH_<REGEX>), with <STRUCTURE> and <REGEX>
+dnl translated to uppercase.
+AC_DEFUN([OVS_FIND_FIELD_IFELSE], [
+ AC_MSG_CHECKING([whether $2 has member $3 in $1])
+ if test -f $1; then
+ awk '/$2.{/,/^}/' $1 2>/dev/null | grep '$3'
+ status=$?
+ case $status in
+ 0)
+ AC_MSG_RESULT([yes])
+ m4_if([$4], [], [OVS_DEFINE([HAVE_]m4_toupper([$2])[_WITH_]m4_toupper([$3]))], [$4])
+ ;;
+ 1)
+ AC_MSG_RESULT([no])
+ $5
+ ;;
+ *)
+ AC_MSG_ERROR([grep exited with status $status])
+ ;;
+ esac
+ else
+ AC_MSG_RESULT([file not found])
+ $5
+ fi
+])
+