ACE.java

package org.dcache.acl;

import java.io.Serializable;

import org.dcache.acl.enums.AccessMask;
import org.dcache.acl.enums.AceFlags;
import org.dcache.acl.enums.AceType;
import org.dcache.acl.enums.RsType;
import org.dcache.acl.enums.Who;

/**
 * An access control list (ACL) is an array of access control entries (ACE).
 *
 * @author David Melkumyan, DESY Zeuthen
 *
 */
public class ACE implements Serializable
{
    private static final long serialVersionUID = -7088617639500399472L;

    private static final String SPACE_SEPARATOR = " ";
    private static final String SEPARATOR = ":";

    /**
     * Type of ACE (ALLOW / DENY)
     */
    private final AceType _type;

    /**
     * The ACE flags (combination of values from AceFlags enumeration)
     */
    private final int _flags;

    /**
     * The access mask (combination of values from AccessMask enumeration)
     */
    private final int _accessMsk;

    /**
     * The subject (combination of values from Who enumeration)
     */
    private final Who _who;

    /**
     * Virtual user or group ID (equals to -1 if who is special subject)
     */
    private final int _whoID;

    /**
     * @param type
     *            Type of ACE (ALLOW / DENY)
     * @param flags
     *            ACE flags
     * @param accessMsk
     *            Access mask
     * @param who
     *            Subject
     * @param whoID
     *            Virtual user or group ID
     */
    public ACE(AceType type, int flags, int accessMsk, Who who, int whoID) {
        _type = type;
        _flags = flags;
        _accessMsk = accessMsk;
        _who = who;
        _whoID = whoID;
    }

    public int getAccessMsk() {
        return _accessMsk;
    }

    public int getFlags() {
        return _flags;
    }

    public AceType getType() {
        return _type;
    }

    public Who getWho() {
        return _who;
    }

    public int getWhoID() {
        return _whoID;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final ACE other = (ACE) obj;
        if (_type != other._type) {
            return false;
        }
        if (_flags != other._flags) {
            return false;
        }
        if (_accessMsk != other._accessMsk) {
            return false;
        }
        if (_who != other._who) {
            return false;
        }
        if (_whoID != other._whoID) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        return _type.hashCode() ^ _flags ^ _accessMsk ^ _who.hashCode() ^ _whoID ;
    }

    public String toNFSv4String(RsType rsType) {
        StringBuilder sb = new StringBuilder();
        sb.append(_who.getAbbreviation());
        if (_who == Who.USER || _who == Who.GROUP) {
            sb.append(SEPARATOR).append(_whoID);
        }
        sb.append(SEPARATOR).append(AccessMask.asString(_accessMsk, rsType));
        if (_flags != 0) {
            sb.append(SEPARATOR).append(AceFlags.asString(_flags));
        }
        sb.append(SEPARATOR).append(_type.getAbbreviation());
        return sb.toString();
    }

    public String toOrgString() {
        StringBuilder sb = new StringBuilder();
        sb.append(_type.getValue()).append(SPACE_SEPARATOR);
        sb.append(_flags).append(SPACE_SEPARATOR);
        sb.append(_accessMsk).append(SPACE_SEPARATOR);
        sb.append(_who.getValue()).append(SPACE_SEPARATOR);
        sb.append(_whoID).append(SPACE_SEPARATOR);
        return sb.toString();
    }

    @Override
    public String toString() {
        return toString(null);
    }

    public String toString(RsType rsType) {
        StringBuilder sb = new StringBuilder();
        sb.append("type = ")
            .append(_type)
            .append(", flags = ")
            .append(AceFlags.asString(_flags))
            .append(", accessMsk = ")
            .append(AccessMask.asString(_accessMsk, rsType))
            .append(", who = ")
            .append(_who)
            .append(", whoID = ").append(_whoID);

        return sb.toString();
    }

    /**
     * Represents ACE in the extra format.
     * <p>
     * Example: USER:12457:+lfsD
     *
     * @param rsType -
     *            resource type
     * @return ACE in extra format
     * @throws ACLException
     *             if ACE cannot be represented in extra format
     */
    public String toExtraFormat(RsType rsType) throws ACLException {
        StringBuilder sb = new StringBuilder();
        sb.append(_who.getAbbreviation());
        if (_who == Who.USER || _who == Who.GROUP) {
            sb.append(SEPARATOR).append(_whoID);
        }

        sb.append(SEPARATOR);

        switch (_type) {
        case ACCESS_ALLOWED_ACE_TYPE:
            sb.append("+");
            break;

        case ACCESS_DENIED_ACE_TYPE:
            sb.append("-");
            break;

        default:
            throw new ACLException("Unsupported access type: " + _type);
        }

        sb.append(AccessMask.asString(_accessMsk, rsType));

        if (_flags != 0) {
            sb.append(SEPARATOR).append(AceFlags.asString(_flags));
        }

        return sb.toString();
    }
}