/*
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed 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
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.jk.common;

import java.io.IOException;
import java.util.Vector;

import org.apache.jk.apr.AprImpl;
import org.apache.jk.core.Msg;
import org.apache.jk.core.MsgContext;
import org.apache.jk.core.WorkerEnv;
import org.apache.tomcat.util.IntrospectionUtils;
import org.apache.tomcat.util.buf.C2BConverter;

/* The code is a bit confusing at this moment - the class is used as
   a Bean, or ant Task, or CLI - i.e. you set properties and call execute.

   That's different from the rest of jk handlers wich are stateless ( but
   similar with Coyote-http ).
*/


/** Handle the shared memory objects.
 *
 * @author Costin Manolache
 */
public class Shm extends JniHandler {
    String file="/tmp/shm.file";
    int size;
    String host="localhost";
    int port=8009;
    String unixSocket;

    boolean help=false;
    boolean unregister=false;
    boolean reset=false;
    String dumpFile=null;

    Vector groups=new Vector();
    
    // Will be dynamic ( getMethodId() ) after things are stable 
    static final int SHM_WRITE_SLOT=2;
    static final int SHM_RESET=5;
    static final int SHM_DUMP=6;
    
    public Shm() {
    }

    /** Scoreboard location
     */
    public void setFile( String f ) {
        file=f;
    }

    /** Copy the scoreboard in a file for debugging
     *  Will also log a lot of information about what's in the scoreboard.
     */
    public void setDump( String dumpFile ) {
        this.dumpFile=dumpFile;
    }
    
    /** Size. Used only if the scoreboard is to be created.
     */
    public void setSize( int size ) {
        this.size=size;
    }

    /** Set this to get the scoreboard reset.
     *  The shm segment will be destroyed and a new one created,
     *  with the provided size.
     *
     *  Requires "file" and "size".
     */
    public void setReset(boolean b) {
        reset=true;
    }

    /** Ajp13 host
     */
    public void setHost( String host ) {
        this.host=host;
    }

    /** Mark this instance as belonging to a group
     */
    public void setGroup( String grp ) {
        groups.addElement( grp );
    }

    /** Ajp13 port
     */
    public void setPort( int port ) {
        this.port=port;
    }

    /** Unix socket where tomcat is listening.
     *  Use it only if tomcat is on the same host, of course
     */
    public void setUnixSocket( String unixSocket  ) {
        this.unixSocket=unixSocket;
    }

    /** Set this option to mark the tomcat instance as
        'down', so apache will no longer forward messages to it.
        Note that requests with a session will still try this
        host first.

        This can be used to implement gracefull shutdown.

        Host and port are still required, since they are used
        to identify tomcat.
    */
    public void setUnregister( boolean unregister  ) {
        this.unregister=true;
    }
    
    public void init() throws IOException {
        super.initNative( "shm" );
        if( apr==null ) return;
        if( file==null ) {
            log.error("No shm file, disabling shared memory");
            apr=null;
            return;
        }

        // Set properties and call init.
        setNativeAttribute( "file", file );
        if( size > 0 )
            setNativeAttribute( "size", Integer.toString( size ) );
        
        initJkComponent();
    }

    public void resetScoreboard() throws IOException {
        if( apr==null ) return;
        MsgContext mCtx=createMsgContext();
        Msg msg=(Msg)mCtx.getMsg(0);
        msg.reset();

        msg.appendByte( SHM_RESET );
        
        this.invoke( msg, mCtx );
    }

    public void dumpScoreboard(String fname) throws IOException {
        if( apr==null ) return;
        MsgContext mCtx=createMsgContext();
        Msg msg=(Msg)mCtx.getMsg(0);
        C2BConverter c2b=(C2BConverter)mCtx.getNote(C2B_NOTE);
        msg.reset();

        msg.appendByte( SHM_DUMP );

        appendString( msg, fname, c2b);
        
        this.invoke( msg, mCtx );
    }

    /** Register a tomcat instance
     *  XXX make it more flexible
     */
    public void registerTomcat(String host, int port, String unixDomain)
        throws IOException
    {
        String instanceId=host+":" + port;

        String slotName="TOMCAT:" + instanceId;
        MsgContext mCtx=createMsgContext();
        Msg msg=(Msg)mCtx.getMsg(0);
        msg.reset();
        C2BConverter c2b=(C2BConverter)mCtx.getNote(C2B_NOTE);
        
        msg.appendByte( SHM_WRITE_SLOT );
        appendString( msg, slotName, c2b );

        int channelCnt=1;
        if( unixDomain != null ) channelCnt++;

        // number of groups. 0 means the default lb.
        msg.appendInt( groups.size() );
        for( int i=0; i