/*

 * Copyright (c) 2014, 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

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package com.sun.tools.sjavac.client;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.PrintWriter;

import java.io.StringWriter;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.Socket;

import java.net.URI;

import java.util.List;

import java.util.Set;

import com.sun.tools.sjavac.Log;

import com.sun.tools.sjavac.ProblemException;

import com.sun.tools.sjavac.Util;

import com.sun.tools.sjavac.server.CompilationResult;

import com.sun.tools.sjavac.server.PortFile;

import com.sun.tools.sjavac.server.Sjavac;

import com.sun.tools.sjavac.server.SjavacServer;

import com.sun.tools.sjavac.server.SysInfo;

/**

 * Sjavac implementation that delegates requests to a SjavacServer.

 *

 *  <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 SjavacClient implements Sjavac {

    // The id can perhaps be used in the future by the javac server to reuse the

    // JavaCompiler instance for several compiles using the same id.

    private final String id;

    private final String portfileName;

    private final String logfile;

    private final String stdouterrfile;

    private final boolean background;

    // Default keepalive for server is 120 seconds.

    // I.e. it will accept 120 seconds of inactivity before quitting.

    private final int keepalive;

    private final int poolsize;

    // The sjavac option specifies how the server part of sjavac is spawned.

    // If you have the experimental sjavac in your path, you are done. If not, you have

    // to point to a com.sun.tools.sjavac.Main that supports --startserver

    // for example by setting: sjavac=java%20-jar%20...javac.jar%com.sun.tools.sjavac.Main

    private final String sjavacForkCmd;

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

    static int CONNECTION_TIMEOUT = 2000;

    static int MAX_CONNECT_ATTEMPTS = 3;

    static int WAIT_BETWEEN_CONNECT_ATTEMPTS = 2000;

    // Store the server conf settings here.

    private final String settings;

    public SjavacClient(Options options) {

        String tmpServerConf = options.getServerConf();

        String serverConf = (tmpServerConf!=null)? tmpServerConf : "";

        String tmpId = Util.extractStringOption("id", serverConf);

        id = (tmpId!=null) ? tmpId : "id"+(((new java.util.Random()).nextLong())&Long.MAX_VALUE);

        String p = Util.extractStringOption("portfile", serverConf);

        portfileName = (p!=null) ? p : options.getStateDir().toFile().getAbsolutePath()+File.separatorChar+"javac_server";

        logfile = Util.extractStringOption("logfile", serverConf, portfileName + ".javaclog");

        stdouterrfile = Util.extractStringOption("stdouterrfile", serverConf, portfileName + ".stdouterr");

        background = Util.extractBooleanOption("background", serverConf, true);

        sjavacForkCmd = Util.extractStringOption("sjavac", serverConf, "sjavac");

        int poolsize = Util.extractIntOption("poolsize", serverConf);

        keepalive = Util.extractIntOption("keepalive", serverConf, 120);

        this.poolsize = poolsize > 0 ? poolsize : Runtime.getRuntime().availableProcessors();

        settings = (serverConf.equals("")) ? "id="+id+",portfile="+portfileName : serverConf;

    }

    /**

     * Hand out the server settings.

     * @return The server settings, possibly a default value.

     */

    public String serverSettings() {

        return settings;

    }

    /**

     * Make a request to the server only to get the maximum possible heap size to use for compilations.

     *

     * @param port_file The port file used to synchronize creation of this server.

     * @param id The identify of the compilation.

     * @param out Standard out information.

     * @param err Standard err information.

     * @return The maximum heap size in bytes.

     */

    @Override

    public SysInfo getSysInfo() {

        try (Socket socket = tryConnect()) {

            // The ObjectInputStream constructor will block until the

            // corresponding ObjectOutputStream has written and flushed the

            // header, so it is important that the ObjectOutputStreams on server

            // and client are opened before the ObjectInputStreams.

            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());

            ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());

            oos.writeObject(id);

            oos.writeObject(SjavacServer.CMD_SYS_INFO);

            oos.flush();

            return (SysInfo) ois.readObject();

        } catch (IOException | ClassNotFoundException ex) {

            Log.error("[CLIENT] Exception caught: " + ex);

            StringWriter sw = new StringWriter();

            ex.printStackTrace(new PrintWriter(sw));

        }

        return null;

    }

    @Override

    public CompilationResult compile(String protocolId,

                                     String invocationId,

                                     String[] args,

                                     List<File> explicitSources,

                                     Set<URI> sourcesToCompile,

                                     Set<URI> visibleSources) {

        CompilationResult result;

        try (Socket socket = tryConnect()) {

            // The ObjectInputStream constructor will block until the

            // corresponding ObjectOutputStream has written and flushed the

            // header, so it is important that the ObjectOutputStreams on server

            // and client are opened before the ObjectInputStreams.

            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());

            ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());

            oos.writeObject(id);

            oos.writeObject(SjavacServer.CMD_COMPILE);

            oos.writeObject(protocolId);

            oos.writeObject(invocationId);

            oos.writeObject(args);

            oos.writeObject(explicitSources);

            oos.writeObject(sourcesToCompile);

            oos.writeObject(visibleSources);

            oos.flush();

            result = (CompilationResult) ois.readObject();

        } catch (IOException | ClassNotFoundException ex) {

            Log.error("Exception caught: " + ex);

            result = new CompilationResult(CompilationResult.ERROR_FATAL);

            result.stderr = Util.getStackTrace(ex);

        }

        return result;

    }

    private Socket tryConnect() throws IOException {

        PortFile portFile;

        try {

            // This should be taken care of at a higher level (JDK-8048451)

            portFile = SjavacServer.getPortFile(portfileName);

        } catch (FileNotFoundException e) {

            // Reached for instance if directory of port file does not exist

            Log.error("Port file inaccessable: " + e);

            throw new RuntimeException(e);

        }

        for (int i = 0; i < MAX_CONNECT_ATTEMPTS; i++) {

            Log.info(String.format("Trying to connect (attempt %d of %d)",

                                   i+1, MAX_CONNECT_ATTEMPTS));

            try {

                if (!makeSureServerIsRunning(portFile))

                    continue;

                Socket socket = new Socket();

                InetAddress localhost = InetAddress.getByName(null);

                socket.connect(new InetSocketAddress(localhost, portFile.getPort()),

                               CONNECTION_TIMEOUT);

                return socket;

            } catch (ProblemException | IOException ex) {

                Log.error("Caught exception during tryConnect: " + ex);

            }

            try {

                Thread.sleep(WAIT_BETWEEN_CONNECT_ATTEMPTS);

            } catch (InterruptedException e) {

                Thread.currentThread().interrupt();

            }

        }

        throw new IOException("Could not connect to server");

    }

    private boolean makeSureServerIsRunning(PortFile portFile)

            throws IOException, ProblemException, FileNotFoundException {

        synchronized (portFile) {

            portFile.lock();

            portFile.getValues();

            portFile.unlock();

        }

        if (!portFile.containsPortInfo()) {

            String forkCmd = SjavacServer.fork(sjavacForkCmd,

                                               portFile.getFilename(),

                                               logfile,

                                               poolsize,

                                               keepalive,

                                               System.err,

                                               stdouterrfile,

                                               background);

            if (!portFile.waitForValidValues()) {

                // This can be simplified once JDK-8048457 has been addressed

                // since we won't have an SjavacClient if background = false

                if (background) {

                    // There seems be some problem with spawning the external

                    // process (for instance no fork command provided and no

                    // sjavac on path)

                    StringWriter sw = new StringWriter();

                    SjavacClient.printFailedAttempt(forkCmd,

                                                    stdouterrfile,

                                                    new PrintWriter(sw));

                    Log.error(sw.toString());

                }

            }

        }

        return portFile.containsPortInfo();

    }

    public static void printFailedAttempt(String cmd, String f, PrintWriter err) {

        err.println("---- Failed to start javac server with this command -----");

        err.println(cmd);

        try {

            BufferedReader in = new BufferedReader(new FileReader(f));

            err.println("---- stdout/stderr output from attempt to start javac server -----");

            for (;;) {

                String l = in.readLine();

                if (l == null) {

                    break;

                }

                err.println(l);

            }

            err.println("------------------------------------------------------------------");

        } catch (Exception e) {

            err.println("The stdout/stderr output in file " + f + " does not exist and the server did not start.");

        }

    }

    @Override

    public void shutdown() {

        // Nothing to clean up

    }

}