/*

 * Copyright (c) 1999, 2003, 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 com.sun.tools.jdi;

import com.sun.jdi.*;

import com.sun.jdi.connect.*;

import com.sun.jdi.connect.spi.*;

import java.io.IOException;

import java.util.Map;

import java.util.ResourceBundle;

class SharedMemoryTransportService extends TransportService {

    private ResourceBundle messages = null;

    /**

     * The listener returned by startListening

     */

    static class SharedMemoryListenKey extends ListenKey {

        long id;

        String name;

        SharedMemoryListenKey(long id, String name) {

            this.id = id;

            this.name = name;

        }

        long id() {

            return id;

        }

        void setId(long id) {

            this.id = id;

        }

        public String address() {

            return name;

        }

        public String toString() {

            return address();

        }

    }

    SharedMemoryTransportService() {

        System.loadLibrary("dt_shmem");

        initialize();

    }

    public String name() {

        return "SharedMemory";

    }

    public String defaultAddress() {

        return "javadebug";

    }

    /**

     * Return localized description of this transport service

     */

    public String description() {

        synchronized (this) {

            if (messages == null) {

                messages = ResourceBundle.getBundle("com.sun.tools.jdi.resources.jdi");

            }

        }

        return messages.getString("memory_transportservice.description");

    }

    public Capabilities capabilities() {

        return new SharedMemoryTransportServiceCapabilities();

    }

    private native void initialize();

    private native long startListening0(String address) throws IOException;

    private native long attach0(String address, long attachTimeout) throws IOException;

    private native void stopListening0(long id) throws IOException;

    private native long accept0(long id, long acceptTimeout) throws IOException;

    private native String name(long id) throws IOException;

    public Connection attach(String address, long attachTimeout, long handshakeTimeout) throws IOException {

        if (address == null) {

            throw new NullPointerException("address is null");

        }

        long id = attach0(address, attachTimeout);

        SharedMemoryConnection conn = new SharedMemoryConnection(id);

        conn.handshake(handshakeTimeout);

        return conn;

    }

    public TransportService.ListenKey startListening(String address) throws IOException {

        if (address == null || address.length() == 0) {

            address = defaultAddress();

        }

        long id = startListening0(address);

        return new SharedMemoryListenKey(id, name(id));

    }

    public ListenKey startListening() throws IOException {

        return startListening(null);

    }

    public void stopListening(ListenKey listener) throws IOException {

        if (!(listener instanceof SharedMemoryListenKey)) {

            throw new IllegalArgumentException("Invalid listener");

        }

        long id;

        SharedMemoryListenKey key = (SharedMemoryListenKey)listener;

        synchronized (key) {

            id = key.id();

            if (id == 0) {

                throw new IllegalArgumentException("Invalid listener");

            }

            // invalidate the id

            key.setId(0);

        }

        stopListening0(id);

    }

    public Connection accept(ListenKey listener, long acceptTimeout, long handshakeTimeout) throws IOException {

        if (!(listener instanceof SharedMemoryListenKey)) {

            throw new IllegalArgumentException("Invalid listener");

        }

        long transportId;

        SharedMemoryListenKey key = (SharedMemoryListenKey)listener;

        synchronized (key) {

            transportId = key.id();

            if (transportId == 0) {

                throw new IllegalArgumentException("Invalid listener");

            }

        }

        // in theory another thread could call stopListening before

        // accept0 is called. In that case accept0 will try to accept

        // with an invalid "transport id" - this should result in an

        // IOException.

        long connectId = accept0(transportId, acceptTimeout);

        SharedMemoryConnection conn = new SharedMemoryConnection(connectId);

        conn.handshake(handshakeTimeout);

        return conn;

    }

}

class SharedMemoryConnection extends Connection {

    private long id;

    private Object receiveLock = new Object();

    private Object sendLock = new Object();

    private Object closeLock = new Object();

    private boolean closed = false;

    private native byte receiveByte0(long id) throws IOException;

    private native void sendByte0(long id, byte b) throws IOException;

    private native void close0(long id);

    private native byte[] receivePacket0(long id)throws IOException;

    private native void sendPacket0(long id, byte b[]) throws IOException;

    // handshake with the target VM

    void handshake(long handshakeTimeout) throws IOException {

        byte[] hello = "JDWP-Handshake".getBytes("UTF-8");

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

            sendByte0(id, hello[i]);

        }

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

            byte b = receiveByte0(id);

            if (b != hello[i]) {

                throw new IOException("handshake failed - unrecognized message from target VM");

            }

        }

    }

    SharedMemoryConnection(long id) throws IOException {

        this.id = id;

    }

    public void close() {

        synchronized (closeLock) {

            if (!closed) {

                close0(id);

                closed = true;

            }

        }

    }

    public boolean isOpen() {

        synchronized (closeLock) {

            return !closed;

        }

    }

    public byte[] readPacket() throws IOException {

        if (!isOpen()) {

            throw new ClosedConnectionException("Connection closed");

        }

        byte b[];

        try {

            // only one thread may be reading at a time

            synchronized (receiveLock) {

                b  = receivePacket0(id);

            }

        } catch (IOException ioe) {

            if (!isOpen()) {

                throw new ClosedConnectionException("Connection closed");

            } else {

                throw ioe;

            }

        }

        return b;

    }

    public void writePacket(byte b[]) throws IOException {

        if (!isOpen()) {

            throw new ClosedConnectionException("Connection closed");

        }

        /*

         * Check the packet size

         */

        if (b.length < 11) {

            throw new IllegalArgumentException("packet is insufficient size");

        }

        int b0 = b[0] & 0xff;

        int b1 = b[1] & 0xff;

        int b2 = b[2] & 0xff;

        int b3 = b[3] & 0xff;

        int len = ((b0 << 24) | (b1 << 16) | (b2 << 8) | (b3 << 0));

        if (len < 11) {

            throw new IllegalArgumentException("packet is insufficient size");

        }

        /*

         * Check that the byte array contains the complete packet

         */

        if (len > b.length) {

            throw new IllegalArgumentException("length mis-match");

        }

        try {

            // only one thread may be writing at a time

            synchronized(sendLock) {

                sendPacket0(id, b);

            }

        } catch (IOException ioe) {

            if (!isOpen()) {

               throw new ClosedConnectionException("Connection closed");

            } else {

               throw ioe;

            }

        }

    }

}

class SharedMemoryTransportServiceCapabilities extends TransportService.Capabilities {

    public boolean supportsMultipleConnections() {

        return false;

    }

    public boolean supportsAttachTimeout() {

        return true;

    }

    public boolean supportsAcceptTimeout() {

        return true;

    }

    public boolean supportsHandshakeTimeout() {

        return false;

    }

}