/*
 * Copyright (c) 2014, 2016, 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.server;

import com.sun.tools.javac.main.Main;
import com.sun.tools.sjavac.Log;
import com.sun.tools.sjavac.Util;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.nio.file.Path;

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


A RequestHandler handles requests performed over a socket. Specifically it
 - Reads the command string specifying which method is to be invoked
 - Reads the appropriate arguments
 - Delegates the actual invocation to the given sjavac implementation
 - Writes the result back to the socket output stream
None of the work performed by this class is really bound by the CPU. It
should be completely fine to have a large number of RequestHandlers active.
To limit the number of concurrent compilations, use PooledSjavac.
 
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.
/**
 * A RequestHandler handles requests performed over a socket. Specifically it
 *  - Reads the command string specifying which method is to be invoked
 *  - Reads the appropriate arguments
 *  - Delegates the actual invocation to the given sjavac implementation
 *  - Writes the result back to the socket output stream
 *
 * None of the work performed by this class is really bound by the CPU. It
 * should be completely fine to have a large number of RequestHandlers active.
 * To limit the number of concurrent compilations, use PooledSjavac.
 *
 *  <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 RequestHandler extends Thread {

    private final Socket socket;
    private final Sjavac sjavac;

    public RequestHandler(Socket socket, Sjavac sjavac) {
        this.socket = socket;
        this.sjavac = sjavac;
    }

    @Override
    public void run() {

        try (BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
             PrintWriter out = new PrintWriter(socket.getOutputStream(), true)) {

            // Set up logging for this thread. Stream back logging messages to
            // client on the format format "level:msg".
            Log.setLogForCurrentThread(new Log(out, out) {
                @Override
                protected boolean isLevelLogged(Level l) {
                    // Make sure it is up to the client to decide whether or
                    // not this message should be displayed.
                    return true;
                }

                @Override
                protected void printLogMsg(Level msgLevel, String msg) {
                    // Follow sjavac server/client protocol: Send one line
                    // at a time and prefix with message with "level:".
                    Util.getLines(msg)
                        .map(line -> msgLevel + ":" + line)
                        .forEach(line -> super.printLogMsg(msgLevel, line));
                }
            });

            // Read argument array
            int n = Integer.parseInt(in.readLine());
            String[] args = new String[n];
            for (int i = 0; i < n; i++) {
                args[i] = in.readLine();
            }

            // If there has been any internal errors, notify client
            checkInternalErrorLog();

            // Perform compilation
            Main.Result rc = sjavac.compile(args);

            // Send return code back to client
            out.println(LINE_TYPE_RC + ":" + rc.name());

            // Check for internal errors again.
            checkInternalErrorLog();
        } catch (Exception ex) {
            // Not much to be done at this point. The client side request
            // code will most likely throw an IOException and the
            // compilation will fail.
            Log.error(ex);
        } finally {
            Log.setLogForCurrentThread(null);
        }
    }

    private void checkInternalErrorLog() {
        Path errorLog = ServerMain.getErrorLog().getLogDestination();
        if (errorLog != null) {
            Log.error("Server has encountered an internal error. See " + errorLog.toAbsolutePath()
                    + " for details.");
        }
    }
}