/*

 * Copyright (c) 2011-2012, 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.sjavac.server;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.io.FileNotFoundException;

import java.util.HashMap;

import java.util.Map;

import java.net.InetAddress;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.ArrayList;

import java.util.Random;

import com.sun.tools.sjavac.Util;

import com.sun.tools.sjavac.ProblemException;

import java.io.*;

/**

 * 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></p>

 */

public class JavacServer {

    // Responding to this tcp/ip port on localhost.

    private final ServerSocket serverSocket;

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

    private final long myCookie;

    // When the server was started.

    private long serverStart;

    // Accumulated build time for all requests, not counting idle time.

    private long totalBuildTime;

    // The javac server specific log file.

    PrintWriter theLog;

    // The compiler pool that maintains the compiler threads.

    CompilerPool compilerPool;

    // 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;

    final static String PROTOCOL_COOKIE_VERSION = "----THE-COOKIE-V2----";

    final static String PROTOCOL_CWD = "----THE-CWD----";

    final static String PROTOCOL_ID = "----THE-ID----";

    final static String PROTOCOL_ARGS = "----THE-ARGS----";

    final static String PROTOCOL_SOURCES_TO_COMPILE = "----THE-SOURCES-TO-COMPILE----";

    final static String PROTOCOL_VISIBLE_SOURCES = "----THE-VISIBLE-SOURCES----";

    final static String PROTOCOL_END = "----THE-END----";

    final static String PROTOCOL_STDOUT = "----THE-STDOUT----";

    final static String PROTOCOL_STDERR = "----THE-STDERR----";

    final static String PROTOCOL_PACKAGE_ARTIFACTS = "----THE-PACKAGE_ARTIFACTS----";

    final static String PROTOCOL_PACKAGE_DEPENDENCIES = "----THE-PACKAGE_DEPENDENCIES----";

    final static String PROTOCOL_PACKAGE_PUBLIC_APIS = "----THE-PACKAGE-PUBLIC-APIS----";

    final static String PROTOCOL_SYSINFO = "----THE-SYSINFO----";

    final static String PROTOCOL_RETURN_CODE = "----THE-RETURN-CODE----";

    // Check if the portfile is gone, every 5 seconds.

    static int CHECK_PORTFILE_INTERVAL = 5;

    // Wait 2 seconds for response, before giving up on javac server.

    static int CONNECTION_TIMEOUT = 2;

    static int WAIT_BETWEEN_CONNECT_ATTEMPTS = 1;

    static int MAX_NUM_CONNECT_ATTEMPTS = 3;

    /**

     * 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 static int startServer(String settings, PrintStream err) {

        try {

            String portfile = Util.extractStringOption("portfile", settings);

            // The log file collects more javac server specific log information.

            String logfile = Util.extractStringOption("logfile", settings);

            // The stdouterr file collects all the System.out and System.err writes to disk.

            String stdouterrfile = Util.extractStringOption("stdouterrfile", settings);

            // We could perhaps use System.setOut and setErr here.

            // But for the moment we rely on the client to spawn a shell where stdout

            // and stderr are redirected already.

            // The pool size is a limit the number of concurrent compiler threads used.

            // The server might use less than these to avoid memory problems.

            // How many seconds of inactivity will the server accept before quitting?

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

            PortFile portFile = getPortFile(portfile);

            JavacServer s;

            synchronized (portFile) {

                portFile.lock();

                portFile.getValues();

                if (portFile.containsPortInfo()) {

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

                    portFile.unlock();

                    return -1;

                }

                s = new JavacServer(poolsize, logfile);

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

                portFile.unlock();

            }

            // Run the server. Will delete the port file when shutting down.

            // It will shut down automatically when no new requests have come in

            // during the last 125 seconds.

            s.run(portFile, err, keepalive);

            // The run loop for the server has exited.

            return 0;

        } catch (Exception e) {

            e.printStackTrace(err);

            return -1;

        }

    }

    /**

     * Spawn the server instance.

     */

    private JavacServer(int poolSize, String logfile) throws IOException {

        serverStart = System.currentTimeMillis();

        // Create a server socket on a random port that is bound to the localhost/127.0.0.1 interface.

        // I.e only local processes can connect to this port.

        serverSocket = new ServerSocket(0, 128, InetAddress.getByName(null));

        compilerPool = new CompilerPool(poolSize, this);

        Random rnd = new Random();

        myCookie = rnd.nextLong();

        theLog = new PrintWriter(logfile);

        log("Javac server started. port=" + getPort() + " date=" + (new java.util.Date()) + " with poolsize=" + poolSize);

        flushLog();

    }

    /**

     * Fork a background process. Returns the command line used that can be printed if something failed.

     */

            throws IOException, ProblemException {

        if (stdouterrfile != null && stdouterrfile.trim().equals("")) {

            stdouterrfile = null;

        }

        final String startserver = "--startserver:portfile=" + portfile + ",logfile=" + logfile + ",stdouterrfile=" + stdouterrfile + ",poolsize=" + poolsize + ",keepalive="+ keepalive;

            sjavac += "%20" + startserver;

            sjavac = sjavac.replaceAll("%20", " ");

            sjavac = sjavac.replaceAll("%2C", ",");

            // If the java/sh/cmd launcher fails the failure will be captured by stdouterr because of the redirection here.

            String[] cmd = {"/bin/sh", "-c", sjavac + " >> " + stdouterrfile + " 2>&1"};

            if (!(new File("/bin/sh")).canExecute()) {

                ArrayList<String> wincmd = new ArrayList<>();

                wincmd.add("cmd");

                wincmd.add("/c");

                wincmd.add("start");

                wincmd.add("cmd");

                wincmd.add("/c");

                wincmd.add(sjavac + " >> " + stdouterrfile + " 2>&1");

                cmd = wincmd.toArray(new String[wincmd.size()]);

            }

            Process pp = null;

            try {

                pp = Runtime.getRuntime().exec(cmd);

            } catch (Exception e) {

                e.printStackTrace(err);

                e.printStackTrace(new PrintWriter(stdouterrfile));

            }

            StringBuilder rs = new StringBuilder();

            for (String s : cmd) {

                rs.append(s + " ");

            }

            return rs.toString();

        }

        // Do not spawn a background server, instead run it within the same JVM.

        Thread t = new Thread() {

            @Override

            public void run() {

                try {

                    JavacServer.startServer(startserver, err);

                } catch (Throwable t) {

                    t.printStackTrace(err);

                }

            }

        };

        t.start();

        return "";

    }

    /**

     * Run the server thread until it exits. Either because of inactivity or because the port file has been deleted by someone else, or overtaken by some other

     * javac server.

     */

    private void run(PortFile portFile, PrintStream err, int keepalive) {

        boolean fileDeleted = false;

        long timeSinceLastCompile;

        try {

            // Every 5 second (check_portfile_interval) we test if the portfile has disappeared => quit

            // Or if the last request was finished more than 125 seconds ago => quit

            // 125 = seconds_of_inactivity_before_shutdown+check_portfile_interval

            serverSocket.setSoTimeout(CHECK_PORTFILE_INTERVAL*1000);

            for (;;) {

                try {

                    Socket s = serverSocket.accept();

                    CompilerThread ct = compilerPool.grabCompilerThread();

                    ct.setSocket(s);

                    compilerPool.execute(ct);

                    flushLog();

                } catch (java.net.SocketTimeoutException e) {

                    if (compilerPool.numActiveRequests() > 0) {

                        // Never quit while there are active requests!

                        continue;

                    }

                    // If this is the timeout after the portfile

                    // has been deleted by us. Then we truly stop.

                    if (fileDeleted) {

                        log("Quitting because of "+(keepalive+CHECK_PORTFILE_INTERVAL)+" seconds of inactivity!");

                        break;

                    }

                    // Check if the portfile is still there.

                    if (!portFile.exists()) {

                        // Time to quit because the portfile was deleted by another

                        // process, probably by the makefile that is done building.

                        log("Quitting because portfile was deleted!");

                        flushLog();

                        break;

                    }

                    // Check if portfile.stop is still there.

                    if (portFile.markedForStop()) {

                        // Time to quit because another process touched the file

                        // server.port.stop to signal that the server should stop.

                        // This is necessary on some operating systems that lock

                        // the port file hard!

                        log("Quitting because a portfile.stop file was found!");

                        portFile.delete();

                        flushLog();

                        break;

                    }

                    // Does the portfile still point to me?

                    if (!portFile.stillMyValues()) {

                        // Time to quit because another build has started.

                        log("Quitting because portfile is now owned by another javac server!");

                        flushLog();

                        break;

                    }

                    // Check how long since the last request finished.

                    long diff = System.currentTimeMillis() - compilerPool.lastRequestFinished();

                    if (diff < keepalive * 1000) {

                        // Do not quit if we have waited less than 120 seconds.

                        continue;

                    }

                    // Ok, time to quit because of inactivity. Perhaps the build

                    // was killed and the portfile not cleaned up properly.

                    portFile.delete();

                    fileDeleted = true;

                    log("" + keepalive + " seconds of inactivity quitting in "

                        + CHECK_PORTFILE_INTERVAL + " seconds!");

                    flushLog();

                    // Now we have a second 5 second grace

                    // period where javac remote requests

                    // that have loaded the data from the

                    // recently deleted portfile can connect

                    // and complete their requests.

                }

            }

        } catch (Exception e) {

            e.printStackTrace(err);

            e.printStackTrace(theLog);

            flushLog();

        } finally {

            compilerPool.shutdown();

        }

        long realTime = System.currentTimeMillis() - serverStart;

        log("Shutting down.");

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

        flushLog();

    }

    public static void cleanup(String... args) {

        String settings = Util.findServerSettings(args);

        if (settings == null) return;

        String portfile = Util.extractStringOption("portfile", settings);

        String background = Util.extractStringOption("background", settings);

        if (background != null && background.equals("false")) {

            // If the server runs within this jvm, then delete the portfile,

            // since this jvm is about to exit soon.

            File f = new File(portfile);

            f.delete();

        }

    }

}