/*
 * @(#)Policy.java	1.2 00/08/18
 *
 * Copyright 1999-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 */

package com.sun.security.sasl.util; 

import com.sun.security.sasl.preview.Sasl;
import java.util.Hashtable;

/**
 * Static class that contains utilities for dealing with Java SASL
 * security policy-related properties.
 *
 * @author Rosanna Lee
 */
final public class Policy {
    public final static int NOPLAINTEXT = 0x0001;
    public final static int NOACTIVE = 0x0002;
    public final static int NODICTIONARY = 0x0004;
    public final static int FORWARD_SECRECY = 0x0008;
    public final static int NOANONYMOUS = 0x0010;
    public final static int PASS_CREDENTIALS = 0x0200;

    /**
     * Determines whether a mechanism's characteristics, as defined in flags,
     * fits the security policy properties found in props.
     * @param flags The mechanism's security characteristics
     * @param props The security policy properties to check
     * @return true if passes; false if fails
     */
    public static boolean checkPolicy(int flags, Hashtable props) {
	if (props == null) {
	    return true;
	}

	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_NOPLAINTEXT))
	    && (flags&NOPLAINTEXT) == 0) {
	    return false;
	}
	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_NOACTIVE))
	    && (flags&NOACTIVE) == 0) {
	    return false;
	}
	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_NODICTIONARY))
	    && (flags&NODICTIONARY) == 0) {
	    return false;
	}
	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_NOANONYMOUS))
	    && (flags&NOANONYMOUS) == 0) {
	    return false;
	}
	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_FORWARD_SECRECY))
	    && (flags&FORWARD_SECRECY) == 0) {
	    return false;
	}
	if ("true".equalsIgnoreCase((String)props.get(Sasl.POLICY_PASS_CREDENTIALS))
	    && (flags&PASS_CREDENTIALS) == 0) {
	    return false;
	}

	return true;
    }

    /**
     * Given a list of mechanisms and their characteristics, select the
     * subset that conforms to the policies defined in props.
     * Useful for SaslXXXFactory.getMechanismNames(props) implementations.
     *
     */
    public static String[] filterMechs(String[] mechs, int[] policies, 
	Hashtable props) {
	if (props == null) {
	    return (String[])mechs.clone();
	}

	boolean[] passed = new boolean[mechs.length];
	int count = 0;
	for (int i = 0; i< mechs.length; i++) {
	    if (passed[i] = checkPolicy(policies[i], props)) {
		++count;
	    }
	}
	String[] answer = new String[count];
	for (int i = 0, j=0; i< mechs.length; i++) {
	    if (passed[i]) {
		answer[j++] = mechs[i];
	    }
	}
	
	return answer;
    }
}