# This is example of file:  $MAILVAR/db/aliases.zmsh 
# If that file exists, it contains scripts defining our databases
# at load-in time (relation entries), and also runtime callable
# entrypoint  aliases(uname) { ... }  which "return 1" in case no
# lookup succeeds.  It yields the first lookup result that succeeded.
# Also, successfull lookup must yield file privileges of the database
# file where the lookup was done.  The return is done to a "priv"
# variable which has local scope in the caller's symbol stack.

if [ -f $MAILVAR/db/aliases ]; then
	# Need to be updated at boot ?
	if [ ! -f $MAILVAR/db/aliases$DBEXTtest -o \
	     $MAILVAR/db/aliases -nt $MAILVAR/db/aliases$DBEXTtest ]; then
		# Yes, so update!
		$MAILBIN/newdb -l -a $MAILVAR/db/aliases
	fi

# ---- raw relation entries

	relation -lmt $DBTYPE -f $MAILVAR/db/aliases$DBEXT aliasesdb

# ---- interface function

	aliases(key) {
	    local a
	    # Usage of "if" around the lookup and store is IMPORTANT!
	    if a="$(aliasesdb "$key")" ; then
		priv=$(filepriv -M 644 $MAILVAR/db/aliases$DBEXTtest \
				$(db owner aliasesdb)) &&
		return "$a"
	    fi
	    return 1
	}

#
# Substitution to "priv" variable DOES NOT WORK in following code:
# (use the style above with 'if' where the db-lookup is the conditionality)
#
#	aliases(key) {
#	    local a
#	    a="$(aliasesdb "$key")" &&
#		priv=$(filepriv -M 644 $MAILVAR/db/aliases$DBEXTtest \
#				$(db owner aliasesdb)) &&
#		return "$a"
#	    return 1
#	}

else
	aliases () { return 1 }
fi