/*

 * 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

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

 *

 * 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.

 *

 */

package sun.security.ssl;

import java.io.*;

import java.net.*;

import java.util.Date;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.NoSuchElementException;

import java.util.Vector;

import javax.net.ssl.SSLSession;

import javax.net.ssl.SSLSessionContext;

import javax.net.ssl.SSLSessionBindingListener;

import javax.net.ssl.SSLSessionBindingEvent;

import javax.net.ssl.SSLPeerUnverifiedException;

import javax.net.ssl.SSLSession;

import sun.security.util.Cache;

final class SSLSessionContextImpl implements SSLSessionContext {

    private Cache sessionCache;         // session cache, session id as key

    private Cache sessionHostPortCache; // session cache, "host:port" as key

    private int cacheLimit;             // the max cache size

    private int timeout;                // timeout in seconds

    private static final Debug debug = Debug.getInstance("ssl");

    // package private

    SSLSessionContextImpl() {

        cacheLimit = getDefaultCacheLimit();    // default cache size

        timeout = 86400;                        // default, 24 hours

        // use soft reference

        sessionCache = Cache.newSoftMemoryCache(cacheLimit, timeout);

        sessionHostPortCache = Cache.newSoftMemoryCache(cacheLimit, timeout);

    }

    /**

     * Returns the <code>SSLSession</code> bound to the specified session id.

     */

    public SSLSession getSession(byte[] sessionId) {

        if (sessionId == null) {

            throw new NullPointerException("session id cannot be null");

        }

        SSLSessionImpl sess =

                (SSLSessionImpl)sessionCache.get(new SessionId(sessionId));

        if (!isTimedout(sess)) {

            return sess;

        }

        return null;

    }

    /**

     * Returns an enumeration of the active SSL sessions.

     */

    public Enumeration<byte[]> getIds() {

        SessionCacheVisitor scVisitor = new SessionCacheVisitor();

        sessionCache.accept(scVisitor);

        return scVisitor.getSessionIds();

    }

    /**

     * Sets the timeout limit for cached <code>SSLSession</code> objects

     *

     * Note that after reset the timeout, the cached session before

     * should be timed within the shorter one of the old timeout and the

     * new timeout.

     */

    public void setSessionTimeout(int seconds)

                 throws IllegalArgumentException {

        if (seconds < 0) {

            throw new IllegalArgumentException();

        }

        if (timeout != seconds) {

            sessionCache.setTimeout(seconds);

            sessionHostPortCache.setTimeout(seconds);

            timeout = seconds;

        }

    }

    /**

     * Gets the timeout limit for cached <code>SSLSession</code> objects

     */

    public int getSessionTimeout() {

        return timeout;

    }

    /**

     * Sets the size of the cache used for storing

     * <code>SSLSession</code> objects.

     */

    public void setSessionCacheSize(int size)

                 throws IllegalArgumentException {

        if (size < 0)

            throw new IllegalArgumentException();

        if (cacheLimit != size) {

            sessionCache.setCapacity(size);

            sessionHostPortCache.setCapacity(size);

            cacheLimit = size;

        }

    }

    /**

     * Gets the size of the cache used for storing

     * <code>SSLSession</code> objects.

     */

    public int getSessionCacheSize() {

        return cacheLimit;

    }

    // package-private method, used ONLY by ServerHandshaker

    SSLSessionImpl get(byte[] id) {

        return (SSLSessionImpl)getSession(id);

    }

    // package-private method, used ONLY by ClientHandshaker

    SSLSessionImpl get(String hostname, int port) {

        /*

         * If no session caching info is available, we won't

         * get one, so exit before doing a lookup.

         */

        if (hostname == null && port == -1) {

            return null;

        }

        SSLSessionImpl sess =

            (SSLSessionImpl)sessionHostPortCache.get(getKey(hostname, port));

        if (!isTimedout(sess)) {

            return sess;

        }

        return null;

    }

    private String getKey(String hostname, int port) {

        return (hostname + ":" + String.valueOf(port)).toLowerCase();

    }

    // cache a SSLSession

    //

    // In SunJSSE implementation, a session is created while getting a

    // client hello or a server hello message, and cached while the

    // handshaking finished.

    // Here we time the session from the time it cached instead of the

    // time it created, which is a little longer than the expected. So

    // please do check isTimedout() while getting entry from the cache.

    void put(SSLSessionImpl s) {

        sessionCache.put(s.getSessionId(), s);

        // If no hostname/port info is available, don't add this one.

        if ((s.getPeerHost() != null) && (s.getPeerPort() != -1)) {

            sessionHostPortCache.put(

                getKey(s.getPeerHost(), s.getPeerPort()), s);

        }

        s.setContext(this);

    }

    // package-private method, remove a cached SSLSession

    void remove(SessionId key) {

        SSLSessionImpl s = (SSLSessionImpl)sessionCache.get(key);

        if (s != null) {

            sessionCache.remove(key);

            sessionHostPortCache.remove(

                        getKey(s.getPeerHost(), s.getPeerPort()));

        }

    }

    private int getDefaultCacheLimit() {

        int cacheLimit = 0;

        try {

        String s = java.security.AccessController.doPrivileged(

                new java.security.PrivilegedAction<String>() {

                public String run() {

                    return System.getProperty(

                        "javax.net.ssl.sessionCacheSize");

                }

            });

            cacheLimit = (s != null) ? Integer.valueOf(s).intValue() : 0;

        } catch (Exception e) {

        }

        return (cacheLimit > 0) ? cacheLimit : 0;

    }

    boolean isTimedout(SSLSession sess) {

        if (timeout == 0) {

            return false;

        }

        if ((sess != null) && ((sess.getCreationTime() + timeout * 1000L)

                                        <= (System.currentTimeMillis()))) {

            sess.invalidate();

            return true;

        }

        return false;

    }

    final class SessionCacheVisitor

            implements sun.security.util.Cache.CacheVisitor {

        Vector<byte[]> ids = null;

        // public void visit(java.util.Map<Object, Object> map) {}

        public void visit(java.util.Map<Object, Object> map) {

            ids = new Vector<byte[]>(map.size());

            for (Object key : map.keySet()) {

                SSLSessionImpl value = (SSLSessionImpl)map.get(key);

                if (!isTimedout(value)) {

                    ids.addElement(((SessionId)key).getId());

                }

            }

        }

        public Enumeration<byte[]> getSessionIds() {

            return  ids != null ? ids.elements() :

                                  new Vector<byte[]>().elements();

        }

    }

}