/*

 * Copyright (c) 2015, 2017, 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.

 *

 * 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.

 */

import java.io.IOException;

import java.lang.management.ManagementFactory;

import java.time.Duration;

import java.util.List;

import java.util.stream.Collectors;

import java.util.stream.Stream;

import com.sun.management.OperatingSystemMXBean;

import jdk.test.lib.Platform;

/**

 * Useful utilities for testing Process and ProcessHandle.

 */

public abstract class ProcessUtil {

    /**

     * Constructor

     */

    public ProcessUtil() {}

    /**

     * Returns the list of direct children.

     * WIndows conhost.exe children are filtered out.

     * @param ph the Process to get children of

     * @return a list of child ProcessHandles

     */

    public static List<ProcessHandle> getChildren(ProcessHandle ph) {

        return ph.children()

                .filter(ProcessUtil::isNotWindowsConsole)

                .collect(Collectors.toList());

    }

    /**

     * Returns the list of all direct and indirect children.

     * WIndows conhost.exe children are filtered out.

     * @param ph the Process to get children of

     * @return a list of child ProcessHandles

     */

    public static List<ProcessHandle> getDescendants(ProcessHandle ph) {

        return ph.descendants()

                .filter(ProcessUtil::isNotWindowsConsole)

                .collect(Collectors.toList());

    }

    /**

     * Waits for and returns the direct expected Children of a ProcessHandle.

     * For Windows, the conhost.exe children are filtered out.

     *

     * @param ph the process to get the children of

     * @param nchildren the minimum number of children to expect

     * @return a list of ProcessHandles of the children.

     */

    public static List<ProcessHandle> waitForChildren(ProcessHandle ph, long nchildren) {

        List<ProcessHandle> subprocesses = null;

        long count = 0;

        do {

            if (subprocesses != null) {

                // Only wait if this is not the first time looking

                try {

                    Thread.sleep(500L);     // It will happen but don't burn the cpu

                } catch (InterruptedException ie) {

                    // ignore

                }

            }

            subprocesses = getChildren(ph);

            count = subprocesses.size();

            System.out.printf(" waiting for subprocesses of %s to start," +

                    " expected: %d, current: %d%n", ph, nchildren, count);

        } while (count < nchildren);

        return subprocesses;

    }

    /**

     * Waits for and returns all expected Children of a ProcessHandle.

     * For Windows, the conhost.exe children are filtered out.

     *

     * @param ph the process to get the children of

     * @param nchildren the minimum number of children to expect

     * @return a list of ProcessHandles of the children.

     */

    public static List<ProcessHandle> waitForAllChildren(ProcessHandle ph, long nchildren) {

        List<ProcessHandle> subprocesses = null;

        long count = 0;

        do {

            if (subprocesses != null) {

                // Only wait if this is not the first time looking

                try {

                    Thread.sleep(500L);     // It will happen but don't burn the cpu

                } catch (InterruptedException ie) {

                    // ignore

                }

            }

            subprocesses = getDescendants(ph);

            count = subprocesses.size();

            System.out.printf(" waiting for subprocesses of %s to start," +

                    " expected: %d, current: %d%n", ph, nchildren, count);

        } while (count < nchildren);

        return subprocesses;

    }

    /**

     * Destroy all children of the ProcessHandle.

     * (Except the conhost.exe on Windows)

     *

     * @param p a ProcessHandle

     * @return the ProcessHandle

     */

    public static ProcessHandle destroyProcessTree(ProcessHandle p) {

        Stream<ProcessHandle> children = p.descendants().filter(ProcessUtil::isNotWindowsConsole);

        children.forEach(ph -> {

            System.out.printf("destroyProcessTree destroyForcibly%n");

            printProcess(ph);

            ph.destroyForcibly();

        });

        return p;

    }

    /**

     * The OSMXBean for this process.

     */

    public static final OperatingSystemMXBean osMbean =

            (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();

    /**

     * Return the CPU time of the current process according to the OperatingSystemMXBean.

     *

     * @return the CPU time of the current process

     */

    public static Duration MXBeanCpuTime() {

        return Duration.ofNanos(osMbean.getProcessCpuTime());

    }

    /**

     * Return true if the ProcessHandle is a Windows i586 conhost.exe process.

     *

     * @param p the processHandle of the Process

     * @return Return true if the ProcessHandle is for a Windows i586 conhost.exe process

     */

    static boolean isWindowsConsole(ProcessHandle p) {

        return Platform.isWindows() && p.info().command().orElse("").endsWith("C:\\Windows\\System32\\conhost.exe");

    }

    /**

     * Return true if the ProcessHandle is NOT  a Windows i586 conhost.exe process.

     *

     * @param p the processHandle of the Process

     * @return Return true if the ProcessHandle is NOT for a Windows i586 conhost.exe process

     */

    static boolean isNotWindowsConsole(ProcessHandle p) {

        return !isWindowsConsole(p);

    }

    /**

     * Print a formatted string to System.out.

     * @param format the format

     * @param args the argument array

     */

    static void printf(String format, Object... args) {

        String s = String.format(format, args);

        System.out.print(s);

    }

    /**

     * Print information about a process.

     * Prints the pid, if it is alive, and information about the process.

     * @param ph the processHandle at the top

     */

    static void printProcess(ProcessHandle ph) {

        printProcess(ph, "");

    }

    /**

     * Print information about a process.

     * Prints the pid, if it is alive, and information about the process.

     * @param ph the processHandle at the top

     * @param prefix the String to prefix the output with

     */

    static void printProcess(ProcessHandle ph, String prefix) {

        printf("%spid %s, alive: %s; parent: %s, %s%n", prefix,

                ph.pid(), ph.isAlive(), ph.parent(), ph.info());

    }

    /**

     * Print the process hierarchy as visible via ProcessHandle.

     * Prints the pid, if it is alive, and information about the process.

     * @param ph the processHandle at the top

     * @param prefix the String to prefix the output with

     */

    static void printDeep(ProcessHandle ph, String prefix) {

        printProcess(ph, prefix);

        ph.children().forEach(p -> printDeep(p, prefix + "   "));

    }

    /**

     * Use the native command to list the active processes.

     */

    static void logTaskList() {

        String[] windowsArglist = {"tasklist.exe", "/v"};

        String[] unixArglist = {"ps", "-ef"};

        String[] argList = null;

        if (Platform.isWindows()) {

            argList = windowsArglist;

        } else if (Platform.isLinux() || Platform.isOSX()) {

            argList = unixArglist;

        } else {

            return;

        }

        ProcessBuilder pb = new ProcessBuilder(argList);

        pb.inheritIO();

        try {

            Process proc = pb.start();

            proc.waitFor();

        } catch (IOException | InterruptedException ex) {

            ex.printStackTrace();

        }

    }

}