/*

 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.security.pkcs11;

import java.util.*;

import java.lang.ref.*;

import java.security.Key;

import sun.security.util.Cache;

/**

 * Key to P11Key translation cache. The PKCS#11 token can only perform

 * operations on keys stored on the token (permanently or temporarily). That

 * means that in order to allow the PKCS#11 provider to use keys from other

 * providers, we need to transparently convert them to P11Keys. The engines

 * do that using (Secret)KeyFactories, which in turn use this class as a

 * cache.

 *

 * There are two KeyCache instances per provider, one for secret keys and

 * one for public and private keys.

 *

 * @author  Andreas Sterbenz

 * @since   1.5

 */

final class KeyCache {

    private final Cache<IdentityWrapper, P11Key> strongCache;

    private WeakReference<Map<Key,P11Key>> cacheReference;

    KeyCache() {

        strongCache = Cache.newHardMemoryCache(16);

    }

    private static final class IdentityWrapper {

        final Object obj;

        IdentityWrapper(Object obj) {

            this.obj = obj;

        }

        public boolean equals(Object o) {

            if (this == o) {

                return true;

            }

            if (o instanceof IdentityWrapper == false) {

                return false;

            }

            IdentityWrapper other = (IdentityWrapper)o;

            return this.obj == other.obj;

        }

        public int hashCode() {

            return System.identityHashCode(obj);

        }

    }

    synchronized P11Key get(Key key) {

        P11Key p11Key = strongCache.get(new IdentityWrapper(key));

        if (p11Key != null) {

            return p11Key;

        }

        Map<Key,P11Key> map =

                (cacheReference == null) ? null : cacheReference.get();

        if (map == null) {

            return null;

        }

        return map.get(key);

    }

    synchronized void put(Key key, P11Key p11Key) {

        strongCache.put(new IdentityWrapper(key), p11Key);

        Map<Key,P11Key> map =

                (cacheReference == null) ? null : cacheReference.get();

        if (map == null) {

            map = new IdentityHashMap<>();

            cacheReference = new WeakReference<>(map);

        }

        map.put(key, p11Key);

    }

}