/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

package com.sun.star.comp.connections;


import com.sun.star.comp.loader.FactoryHelper;
import com.sun.star.connection.XConnection;
import com.sun.star.lang.XMultiServiceFactory;
import com.sun.star.lang.XSingleServiceFactory;
import com.sun.star.registry.XRegistryKey;

/**
 * The <code>PipedConnection</code> is a component that implements the
 * <code>XConnection</code> Interface.
 * <p>It is useful for <code>Thread</code> communication in one Process.</p>
 *
 * @see         com.sun.star.connection.XConnection
 * @see         com.sun.star.comp.loader.JavaLoader
 * @since       UDK1.0
 */
public class PipedConnection implements XConnection {
    /**
     * When set to true, enables various debugging output.
     */
    public static final boolean DEBUG = false;

    /**
     * The name of the service, the <code>JavaLoader</code> accesses this through
     * reflection.
     */
    static private final String __serviceName = "com.sun.star.connection.PipedConnection";

    /**
     * Gives a factory for creating the service.
     * <p>This method is called by the <code>JavaLoader</code>.</p>
     *
     * @param   implName     the name of the implementation for which a service is desired.
     * @param   multiFactory the service manager to be uses if needed.
     * @param   regKey       the registryKey.
     * @return  returns a <code>XSingleServiceFactory</code> for creating the component.
     *
     * @see                  com.sun.star.comp.loader.JavaLoader
     */
    public static XSingleServiceFactory __getServiceFactory(String implName,
                                                          XMultiServiceFactory multiFactory,
                                                          XRegistryKey regKey)
    {
        XSingleServiceFactory xSingleServiceFactory = null;

        if (implName.equals(PipedConnection.class.getName()) )
            xSingleServiceFactory = FactoryHelper.getServiceFactory(PipedConnection.class,
                                                                    __serviceName,
                                                                    multiFactory,
                                                                    regKey);

        return xSingleServiceFactory;
    }

    /**
     * The amount of time in milliseconds, to wait to see check the buffers.
     */
    protected static final int __waitTime = 10000;

    protected byte             _buffer[] = new byte[4096];
    protected int              _in,
                               _out;
    protected boolean          _closed;
    protected PipedConnection  _otherSide;

    /**
     * Constructs a new <code>PipedConnection</code>, sees if there is an other
     * side, which it should be connected to.
     *
     * @param    args   Another side could be in index 0.
     */
    public PipedConnection(Object args[]) throws com.sun.star.uno.RuntimeException {
        if (DEBUG) System.err.println("##### " + getClass().getName() + " - instantiated");

        _otherSide = (args.length == 1) ? (PipedConnection)args[0] : null;
        if(_otherSide != null) {
            if(_otherSide == this)
                throw new RuntimeException("can not connect to myself");

            _otherSide._otherSide = this;
        }
    }

    /**
     * This is a private method, used to cummunicate internal in the pipe.
     */
    private synchronized void receive(byte aData[]) throws com.sun.star.io.IOException {
        int bytesWritten = 0;

        if(DEBUG) System.err.println("##### PipedConnection.receive - bytes:" + aData.length + " at:" + _out);

        while(bytesWritten < aData.length) {
            // wait until it is not full anymore
            while(_out == (_in - 1) || (_in == 0 && _out == _buffer.length - 1)) {
                try {
                    notify(); // the buffer is full, signal it

                    wait(__waitTime);
                }
                catch(InterruptedException interruptedException) {
                    throw new com.sun.star.io.IOException(interruptedException);
                }
            }

            if(_closed) throw new com.sun.star.io.IOException("connection has been closed");

            int bytes  ;

            if(_out < _in) {
                bytes = Math.min(aData.length - bytesWritten, _in - _out - 1);

                System.arraycopy(aData, bytesWritten, _buffer, _out, bytes);
            }
            else {
                if(_in > 0){
                    bytes = Math.min(aData.length - bytesWritten, _buffer.length - _out);
                }
                else {
                    bytes = Math.min(aData.length - bytesWritten, _buffer.length - _out - 1);
                }

                System.arraycopy(aData, bytesWritten, _buffer, _out, bytes);
            }

            bytesWritten += bytes;
            _out += bytes;
            if(_out >= _buffer.length)
                _out = 0;
        }
    }

    /**
     * Read the required number of bytes.
     *
     * @param   aReadBytes   the out parameter, where the bytes have to be placed.
     * @param   nBytesToRead the number of bytes to read.
     * @return  the number of bytes read.
     *
     * @see     com.sun.star.connection.XConnection#read
     */
    public synchronized int read(/*OUT*/byte[][] aReadBytes, int nBytesToRead) throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
        aReadBytes[0] = new byte[nBytesToRead];

        if(DEBUG) System.err.println("##### PipedConnection.read - bytes:" + nBytesToRead + " at:" + _in);

        // loop while not all bytes read or when closed but there is still data
        while(nBytesToRead > 0 && (_in != _out || !_closed)) {
            while(_in == _out && !_closed) {
                try {
                    notify(); // the buffer is empty, signal it

                    wait(__waitTime); // we wait for data or for the pipe to be closed
                }
                catch(InterruptedException interruptedException) {
                    throw new com.sun.star.io.IOException(interruptedException);
                }
            }

            if(_in < _out) {
                int bytes = Math.min(nBytesToRead, _out - _in);

                System.arraycopy(_buffer, _in, aReadBytes[0], aReadBytes[0].length - nBytesToRead, bytes);

                nBytesToRead -= bytes;
                _in += bytes;
            }
            else if(_in > _out) {
                int bytes = Math.min(nBytesToRead, _buffer.length - _in);

                System.arraycopy(_buffer, _in, aReadBytes[0], aReadBytes[0].length - nBytesToRead, bytes);

                nBytesToRead -= bytes;
                _in += bytes;
                if(_in >= _buffer.length)
                    _in = 0;
            }
        }

        if(nBytesToRead > 0) { // not all bytes read
            byte tmp[] = new byte[aReadBytes[0].length - nBytesToRead];
            System.arraycopy(aReadBytes[0], 0, tmp, 0, tmp.length);

            aReadBytes[0] = tmp;
        }

        return aReadBytes[0].length;
    }

    /**
     * Write bytes.
     *
     * @param   aData the bytes to write.
     * @see     com.sun.star.connection.XConnection#write
     */
    public void write(byte aData[]) throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
        _otherSide.receive(aData);
    }

    /**
     * Flushes the buffer, notifies if necessary the other side that new data has
     * arrived.
     *
     * @see     com.sun.star.connection.XConnection#flush
     */
    public void flush() throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
        synchronized(_otherSide) {
            _otherSide.notify();
        }
    }

    /**
     * Closes the pipe.
     *
     * @see     com.sun.star.connection.XConnection#close()
     */
    public synchronized void close() throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
        if(!_closed) {
            _closed = true;

            _otherSide.close();

            notify();
        }
    }

    /**
     * Gives a description of this pipe.
     *
     * @return  the description.
     * @see     com.sun.star.connection.XConnection#getDescription
     */
    public String getDescription() throws com.sun.star.uno.RuntimeException {
        return getClass().getName();
    }

}

