/*

 * 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.sjavac.server;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.PrintStream;

import java.io.PrintWriter;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.ServerSocket;

import java.net.Socket;

import java.net.SocketException;

import java.util.HashMap;

import java.util.Map;

import java.util.Random;

import java.util.concurrent.atomic.AtomicBoolean;

import com.sun.tools.sjavac.Util;

import com.sun.tools.sjavac.comp.PooledSjavac;

import com.sun.tools.sjavac.comp.SjavacImpl;

/**

 * The JavacServer class contains methods both to setup a server that responds to requests and methods to connect to this server.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class SjavacServer implements Terminable {

    // Used in protocol to indicate which method to invoke

    public final static String CMD_COMPILE = "compile";

    final private String portfilename;

    final private String logfile;

    final private String stdouterrfile;

    final private int poolsize;

    final private int keepalive;

    final private PrintStream err;

    // The secret cookie shared between server and client through the port file.

    // Used to prevent clients from believing that they are communicating with

    // an old server when a new server has started and reused the same port as

    // an old server.

    private final long myCookie;

    // Accumulated build time, not counting idle time, used for logging purposes

    private long totalBuildTime;

    // The javac server specific log file.

    PrintWriter theLog;

    // The sjavac implementation to delegate requests to

    Sjavac sjavac;

    private ServerSocket serverSocket;

    private PortFile portFile;

    private PortFileMonitor portFileMonitor;

    // Set to false break accept loop

    final AtomicBoolean keepAcceptingRequests = new AtomicBoolean();

    // For the client, all port files fetched, one per started javac server.

    // Though usually only one javac server is started by a client.

    private static Map<String, PortFile> allPortFiles;

    private static Map<String, Long> maxServerMemory;

    public SjavacServer(String settings, PrintStream err) throws FileNotFoundException {

        this(Util.extractStringOption("portfile", settings),

             Util.extractStringOption("logfile", settings),

             Util.extractStringOption("stdouterrfile", settings),

             Util.extractIntOption("poolsize", settings, Runtime.getRuntime().availableProcessors()),

             Util.extractIntOption("keepalive", settings, 120),

             err);

    }

    public SjavacServer(String portfilename,

                        String logfile,

                        String stdouterrfile,

                        int poolsize,

                        int keepalive,

                        PrintStream err)

                                throws FileNotFoundException {

        this.portfilename = portfilename;

        this.logfile = logfile;

        this.stdouterrfile = stdouterrfile;

        this.poolsize = poolsize;

        this.keepalive = keepalive;

        this.err = err;

        myCookie = new Random().nextLong();

        theLog = new PrintWriter(logfile);

    }

    /**

     * Acquire the port file. Synchronized since several threads inside an smart javac wrapper client acquires the same port file at the same time.

     */

        if (allPortFiles == null) {

            allPortFiles = new HashMap<>();

        }

        PortFile pf = allPortFiles.get(filename);

        // Port file known. Does it still exist?

        if (pf != null) {

            try {

                if (!pf.exists())

                    pf = null;

            } catch (IOException ioex) {

                ioex.printStackTrace();

            }

        }

        if (pf == null) {

            pf = new PortFile(filename);

            allPortFiles.put(filename, pf);

        }

        return pf;

    }

    /**

     * Get the cookie used for this server.

     */

    long getCookie() {

        return myCookie;

    }

    /**

     * Get the port used for this server.

     */

    int getPort() {

        return serverSocket.getLocalPort();

    }

    /**

     * Sum up the total build time for this javac server.

     */

    public void addBuildTime(long inc) {

        totalBuildTime += inc;

    }

    /**

     * Log this message.

     */

    public void log(String msg) {

        if (theLog != null) {

            theLog.println(msg);

        } else {

            System.err.println(msg);

        }

    }

    /**

     * Make sure the log is flushed.

     */

    public void flushLog() {

        if (theLog != null) {

            theLog.flush();

        }

    }

    /**

     * Start a server using a settings string. Typically: "--startserver:portfile=/tmp/myserver,poolsize=3" and the string "portfile=/tmp/myserver,poolsize=3"

     * is sent as the settings parameter. Returns 0 on success, -1 on failure.

     */

    public int startServer() throws IOException, InterruptedException {

        long serverStart = System.currentTimeMillis();

        // The port file is locked and the server port and cookie is written into it.

        portFile = getPortFile(portfilename);

        synchronized (portFile) {

            portFile.lock();

            portFile.getValues();

            if (portFile.containsPortInfo()) {

                err.println("Javac server not started because portfile exists!");

                portFile.unlock();

                return -1;

            }

            //           .-----------.   .--------.   .------.

            // socket -->| IdleReset |-->| Pooled |-->| Impl |--> javac

            //           '-----------'   '--------'   '------'

            sjavac = new SjavacImpl();

            sjavac = new PooledSjavac(sjavac, poolsize);

            sjavac = new IdleResetSjavac(sjavac,

                                         this,

                                         keepalive * 1000);

            serverSocket = new ServerSocket();

            InetAddress localhost = InetAddress.getByName(null);

            serverSocket.bind(new InetSocketAddress(localhost, 0));

            // At this point the server accepts connections, so it is  now safe

            // to publish the port / cookie information

            portFile.setValues(getPort(), getCookie());

            portFile.unlock();

        }

        portFileMonitor = new PortFileMonitor(portFile, this);

        portFileMonitor.start();

        log("Sjavac server started. Accepting connections...");

        log("    port: " + getPort());

        log("    time: " + new java.util.Date());

        log("    poolsize: " + poolsize);

        flushLog();

        keepAcceptingRequests.set(true);

        do {

            try {

                Socket socket = serverSocket.accept();

                new Thread(new RequestHandler(socket, sjavac)).start();

            } catch (SocketException se) {

                // Caused by serverSocket.close() and indicates shutdown

            }

        } while (keepAcceptingRequests.get());

        log("Shutting down.");

        // No more connections accepted. If any client managed to connect after

        // the accept() was interrupted but before the server socket is closed

        // here, any attempt to read or write to the socket will result in an

        // IOException on the client side.

        long realTime = System.currentTimeMillis() - serverStart;

        log("Total wall clock time " + realTime + "ms build time " + totalBuildTime + "ms");

        flushLog();

        // Shut down

        sjavac.shutdown();

        return 0;

    }

    @Override

    public void shutdown(String quitMsg) {

        if (!keepAcceptingRequests.compareAndSet(true, false)) {

            // Already stopped, no need to shut down again

            return;

        }

        log("Quitting: " + quitMsg);

        flushLog();

        portFileMonitor.shutdown(); // No longer any need to monitor port file

        // Unpublish port before shutting down socket to minimize the number of

        // failed connection attempts

        try {

            portFile.delete();

        } catch (IOException e) {

            e.printStackTrace(theLog);

        }

        try {

            serverSocket.close();

        } catch (IOException e) {

            e.printStackTrace(theLog);

        }

    }

}