/*

 * Copyright (c) 1996, 2017, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.rmi.server;

import java.io.IOException;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.lang.reflect.Method;

import java.rmi.MarshalException;

import java.rmi.Remote;

import java.rmi.RemoteException;

import java.rmi.UnmarshalException;

import java.rmi.server.Operation;

import java.rmi.server.RemoteCall;

import java.rmi.server.RemoteObject;

import java.rmi.server.RemoteRef;

import java.security.AccessController;

import java.security.PrivilegedAction;

import sun.rmi.runtime.Log;

import sun.rmi.transport.Connection;

import sun.rmi.transport.LiveRef;

import sun.rmi.transport.StreamRemoteCall;

/**

 * NOTE: There is a JDK-internal dependency on the existence of this

 * class's getLiveRef method (as it is inherited by UnicastRef2) in

 * the implementation of javax.management.remote.rmi.RMIConnector.

 */

@SuppressWarnings("deprecation")

public class UnicastRef implements RemoteRef {

    /**

     * Client-side transport log.

     */

    public static final Log clientRefLog =

        Log.getLog("sun.rmi.client.ref", "transport",  Util.logLevel);

    /**

     * Client-side call log.

     */

    public static final Log clientCallLog =

        Log.getLog("sun.rmi.client.call", "RMI",

                   AccessController.doPrivileged((PrivilegedAction<Boolean>) () ->

                       Boolean.getBoolean("sun.rmi.client.logCalls")));

    private static final long serialVersionUID = 8258372400816541186L;

    protected LiveRef ref;

    /**

     * Create a new (empty) Unicast remote reference.

     */

    public UnicastRef() {

    }

    /**

     * Create a new Unicast RemoteRef.

     */

    public UnicastRef(LiveRef liveRef) {

        ref = liveRef;

    }

    /**

     * Returns the current value of this UnicastRef's underlying

     * LiveRef.

     *

     * NOTE: There is a JDK-internal dependency on the existence of

     * this method (as it is inherited by UnicastRef) in the

     * implementation of javax.management.remote.rmi.RMIConnector.

     **/

    public LiveRef getLiveRef() {

        return ref;

    }

    /**

     * Invoke a method. This form of delegating method invocation

     * to the reference allows the reference to take care of

     * setting up the connection to the remote host, marshalling

     * some representation for the method and parameters, then

     * communicating the method invocation to the remote host.

     * This method either returns the result of a method invocation

     * on the remote object which resides on the remote host or

     * throws a RemoteException if the call failed or an

     * application-level exception if the remote invocation throws

     * an exception.

     *

     * @param obj the proxy for the remote object

     * @param method the method to be invoked

     * @param params the parameter list

     * @param opnum  a hash that may be used to represent the method

     * @since 1.2

     */

    public Object invoke(Remote obj,

                         Method method,

                         Object[] params,

                         long opnum)

        throws Exception

    {

        if (clientRefLog.isLoggable(Log.VERBOSE)) {

            clientRefLog.log(Log.VERBOSE, "method: " + method);

        }

        if (clientCallLog.isLoggable(Log.VERBOSE)) {

            logClientCall(obj, method);

        }

        Connection conn = ref.getChannel().newConnection();

        RemoteCall call = null;

        boolean reuse = true;

        /* If the call connection is "reused" early, remember not to

         * reuse again.

         */

        boolean alreadyFreed = false;

        try {

            if (clientRefLog.isLoggable(Log.VERBOSE)) {

                clientRefLog.log(Log.VERBOSE, "opnum = " + opnum);

            }

            // create call context

            call = new StreamRemoteCall(conn, ref.getObjID(), -1, opnum);

            // marshal parameters

            try {

                ObjectOutput out = call.getOutputStream();

                marshalCustomCallData(out);

                Class<?>[] types = method.getParameterTypes();

                for (int i = 0; i < types.length; i++) {

                    marshalValue(types[i], params[i], out);

                }

            } catch (IOException e) {

                clientRefLog.log(Log.BRIEF,

                    "IOException marshalling arguments: ", e);

                throw new MarshalException("error marshalling arguments", e);

            }

            // unmarshal return

            call.executeCall();

            try {

                Class<?> rtype = method.getReturnType();

                if (rtype == void.class)

                    return null;

                ObjectInput in = call.getInputStream();

                /* StreamRemoteCall.done() does not actually make use

                 * of conn, therefore it is safe to reuse this

                 * connection before the dirty call is sent for

                 * registered refs.

                 */

                Object returnValue = unmarshalValue(rtype, in);

                /* we are freeing the connection now, do not free

                 * again or reuse.

                 */

                alreadyFreed = true;

                /* if we got to this point, reuse must have been true. */

                clientRefLog.log(Log.BRIEF, "free connection (reuse = true)");

                /* Free the call's connection early. */

                ref.getChannel().free(conn, true);

                return returnValue;

            } catch (IOException | ClassNotFoundException e) {

                // disable saving any refs in the inputStream for GC

                ((StreamRemoteCall)call).discardPendingRefs();

                clientRefLog.log(Log.BRIEF,

                                 e.getClass().getName() + " unmarshalling return: ", e);

                throw new UnmarshalException("error unmarshalling return", e);

            } finally {

                try {

                    call.done();

                } catch (IOException e) {

                    /* WARNING: If the conn has been reused early,

                     * then it is too late to recover from thrown

                     * IOExceptions caught here. This code is relying

                     * on StreamRemoteCall.done() not actually

                     * throwing IOExceptions.

                     */

                    reuse = false;

                }

            }

        } catch (RuntimeException e) {

            /*

             * Need to distinguish between client (generated by the

             * invoke method itself) and server RuntimeExceptions.

             * Client side RuntimeExceptions are likely to have

             * corrupted the call connection and those from the server

             * are not likely to have done so.  If the exception came

             * from the server the call connection should be reused.

             */

            if ((call == null) ||

                (((StreamRemoteCall) call).getServerException() != e))

            {

                reuse = false;

            }

            throw e;

        } catch (RemoteException e) {

            /*

             * Some failure during call; assume connection cannot

             * be reused.  Must assume failure even if ServerException

             * or ServerError occurs since these failures can happen

             * during parameter deserialization which would leave

             * the connection in a corrupted state.

             */

            reuse = false;

            throw e;

        } catch (Error e) {

            /* If errors occurred, the connection is most likely not

             *  reusable.

             */

            reuse = false;

            throw e;

        } finally {

            /* alreadyFreed ensures that we do not log a reuse that

             * may have already happened.

             */

            if (!alreadyFreed) {

                if (clientRefLog.isLoggable(Log.BRIEF)) {

                    clientRefLog.log(Log.BRIEF, "free connection (reuse = " +

                                           reuse + ")");

                }

                ref.getChannel().free(conn, reuse);

            }

        }

    }

    protected void marshalCustomCallData(ObjectOutput out) throws IOException

    {}

    /**

     * Marshal value to an ObjectOutput sink using RMI's serialization

     * format for parameters or return values.

     */

    protected static void marshalValue(Class<?> type, Object value,

                                       ObjectOutput out)

        throws IOException

    {

        if (type.isPrimitive()) {

            if (type == int.class) {

                out.writeInt(((Integer) value).intValue());

            } else if (type == boolean.class) {

                out.writeBoolean(((Boolean) value).booleanValue());

            } else if (type == byte.class) {

                out.writeByte(((Byte) value).byteValue());

            } else if (type == char.class) {

                out.writeChar(((Character) value).charValue());

            } else if (type == short.class) {

                out.writeShort(((Short) value).shortValue());

            } else if (type == long.class) {

                out.writeLong(((Long) value).longValue());

            } else if (type == float.class) {

                out.writeFloat(((Float) value).floatValue());

            } else if (type == double.class) {

                out.writeDouble(((Double) value).doubleValue());

            } else {

                throw new Error("Unrecognized primitive type: " + type);

            }

        } else {

            out.writeObject(value);

        }

    }

    /**

     * Unmarshal value from an ObjectInput source using RMI's serialization

     * format for parameters or return values.

     */

    protected static Object unmarshalValue(Class<?> type, ObjectInput in)

        throws IOException, ClassNotFoundException

    {

        if (type.isPrimitive()) {

            if (type == int.class) {

                return Integer.valueOf(in.readInt());

            } else if (type == boolean.class) {

                return Boolean.valueOf(in.readBoolean());

            } else if (type == byte.class) {

                return Byte.valueOf(in.readByte());

            } else if (type == char.class) {

                return Character.valueOf(in.readChar());

            } else if (type == short.class) {

                return Short.valueOf(in.readShort());

            } else if (type == long.class) {

                return Long.valueOf(in.readLong());

            } else if (type == float.class) {

                return Float.valueOf(in.readFloat());

            } else if (type == double.class) {

                return Double.valueOf(in.readDouble());

            } else {

                throw new Error("Unrecognized primitive type: " + type);

            }

        } else {

            return in.readObject();

        }

    }

    /**

     * Create an appropriate call object for a new call on this object.

     * Passing operation array and index, allows the stubs generator to

     * assign the operation indexes and interpret them. The RemoteRef

     * may need the operation to encode in for the call.

     */

    public RemoteCall newCall(RemoteObject obj, Operation[] ops, int opnum,

                              long hash)

        throws RemoteException

    {

        clientRefLog.log(Log.BRIEF, "get connection");

        Connection conn = ref.getChannel().newConnection();

        try {

            clientRefLog.log(Log.VERBOSE, "create call context");

            /* log information about the outgoing call */

            if (clientCallLog.isLoggable(Log.VERBOSE)) {

                logClientCall(obj, ops[opnum]);

            }

            RemoteCall call =

                new StreamRemoteCall(conn, ref.getObjID(), opnum, hash);

            try {

                marshalCustomCallData(call.getOutputStream());

            } catch (IOException e) {

                throw new MarshalException("error marshaling " +

                                           "custom call data");

            }

            return call;

        } catch (RemoteException e) {

            ref.getChannel().free(conn, false);

            throw e;

        }

    }

    /**

     * Invoke makes the remote call present in the RemoteCall object.

     *

     * Invoke will raise any "user" exceptions which

     * should pass through and not be caught by the stub.  If any

     * exception is raised during the remote invocation, invoke should

     * take care of cleaning up the connection before raising the

     * "user" or remote exception.

     */

    public void invoke(RemoteCall call) throws Exception {

        try {

            clientRefLog.log(Log.VERBOSE, "execute call");

            call.executeCall();

        } catch (RemoteException e) {

            /*

             * Call did not complete; connection can't be reused.

             */

            clientRefLog.log(Log.BRIEF, "exception: ", e);

            free(call, false);

            throw e;

        } catch (Error e) {

            /* If errors occurred, the connection is most likely not

             *  reusable.

             */

            clientRefLog.log(Log.BRIEF, "error: ", e);

            free(call, false);

            throw e;

        } catch (RuntimeException e) {

            /*

             * REMIND: Since runtime exceptions are no longer wrapped,

             * we can't assue that the connection was left in

             * a reusable state. Is this okay?

             */

            clientRefLog.log(Log.BRIEF, "exception: ", e);

            free(call, false);

            throw e;

        } catch (Exception e) {

            /*

             * Assume that these other exceptions are user exceptions

             * and leave the connection in a reusable state.

             */

            clientRefLog.log(Log.BRIEF, "exception: ", e);

            free(call, true);

            /* reraise user (and unknown) exceptions. */

            throw e;

        }

        /*

         * Don't free the connection if an exception did not

         * occur because the stub needs to unmarshal the

         * return value. The connection will be freed

         * by a call to the "done" method.

         */

    }

    /**

     * Private method to free a connection.

     */

    private void free(RemoteCall call, boolean reuse) throws RemoteException {

        Connection conn = ((StreamRemoteCall)call).getConnection();

        ref.getChannel().free(conn, reuse);

    }

    /**

     * Done should only be called if the invoke returns successfully

     * (non-exceptionally) to the stub. It allows the remote reference to

     * clean up (or reuse) the connection.

     */

    public void done(RemoteCall call) throws RemoteException {

        /* Done only uses the connection inside the call to obtain the

         * channel the connection uses.  Once all information is read

         * from the connection, the connection may be freed.

         */

        clientRefLog.log(Log.BRIEF, "free connection (reuse = true)");

        /* Free the call connection early. */

        free(call, true);

        try {

            call.done();

        } catch (IOException e) {

            /* WARNING: If the conn has been reused early, then it is

             * too late to recover from thrown IOExceptions caught

             * here. This code is relying on StreamRemoteCall.done()

             * not actually throwing IOExceptions.

             */

        }

    }

    /**

     * Log the details of an outgoing call.  The method parameter is either of

     * type java.lang.reflect.Method or java.rmi.server.Operation.

     */

    void logClientCall(Object obj, Object method) {

        clientCallLog.log(Log.VERBOSE, "outbound call: " +

            ref + " : " + obj.getClass().getName() +

            ref.getObjID().toString() + ": " + method);

    }

    /**

     * Returns the class of the ref type to be serialized

     */

    public String getRefClass(ObjectOutput out) {

        return "UnicastRef";

    }

    /**

     * Write out external representation for remote ref.

     */

    public void writeExternal(ObjectOutput out) throws IOException {

        ref.write(out, false);

    }

    /**

     * Read in external representation for remote ref.

     * @exception ClassNotFoundException If the class for an object

     * being restored cannot be found.

     */

    public void readExternal(ObjectInput in)

        throws IOException, ClassNotFoundException

    {

        ref = LiveRef.read(in, false);

    }

    //----------------------------------------------------------------------;

    /**

     * Method from object, forward from RemoteObject

     */

    public String remoteToString() {

        return Util.getUnqualifiedName(getClass()) + " [liveRef: " + ref + "]";

    }

    /**

     * default implementation of hashCode for remote objects

     */

    public int remoteHashCode() {

        return ref.hashCode();

    }

    /** default implementation of equals for remote objects

     */

    public boolean remoteEquals(RemoteRef sub) {

        if (sub instanceof UnicastRef)

            return ref.remoteEquals(((UnicastRef)sub).ref);

        return false;

    }

}