/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * 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).

 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

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 */

/*

 * @test

 * @bug 8054823

 * @summary Tests the setFlag and printFlag attach command

 * @library /test/lib

 * @modules java.base/jdk.internal.misc

 *          java.compiler

 *          java.management

 *          jdk.attach/sun.tools.attach

 *          jdk.internal.jvmstat/sun.jvmstat.monitor

 * @run main AttachSetGetFlag

 */

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.io.InputStream;

import java.lang.reflect.Field;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import sun.tools.attach.HotSpotVirtualMachine;

import jdk.test.lib.Asserts;

import jdk.test.lib.Platform;

import jdk.test.lib.process.ProcessTools;

import com.sun.tools.attach.VirtualMachine;

public class AttachSetGetFlag {

  public static void main(String... args) throws Exception {

    // Test a manageable uintx flag.

    testGetFlag("MaxHeapFreeRatio", "60");

    testSetFlag("MaxHeapFreeRatio", "50", "60");

    // Test a non-manageable size_t flag.

    // Since it is not manageable, we can't test the setFlag functionality.

    testGetFlag("ArrayAllocatorMallocLimit", "128");

    // testSetFlag("ArrayAllocatorMallocLimit", "64", "128");

    // Test a uint flag.

    testGetFlag("ParallelGCThreads", "10");

  }

  public static ProcessBuilder runTarget(String flagName, String flagValue) throws Exception {

    return ProcessTools.createJavaProcessBuilder(

        "-XX:+UnlockExperimentalVMOptions",

        "-XX:" + flagName + "=" + flagValue,

        "AttachSetGetFlag$Target");

  }

  public static void testGetFlag(String flagName, String flagValue) throws Exception {

    ProcessBuilder pb = runTarget(flagName, flagValue);

    Process target = pb.start();

    try {

      waitForReady(target);

      HotSpotVirtualMachine vm = (HotSpotVirtualMachine)VirtualMachine.attach(((Integer)pid).toString());

      // Test Get

      BufferedReader remoteDataReader = new BufferedReader(new InputStreamReader(

          vm.printFlag(flagName)));

      boolean foundExpectedLine = false;

      String line = null;

      while((line = remoteDataReader.readLine()) != null) {

        System.out.println("printFlag: " + line);

        if (line.equals("-XX:" + flagName + "=" + flagValue)) {

          foundExpectedLine = true;

        }

      }

      Asserts.assertTrue(foundExpectedLine, "Didn't get the expected output: '-XX:" + flagName + "=" + flagValue + "'");

      vm.detach();

    }

    finally {

      target.destroy();

      target.waitFor();

    }

  }

  public static void testSetFlag(String flagName, String initialFlagValue, String flagValue) throws Exception {

    ProcessBuilder pb = runTarget(flagName, initialFlagValue);

    Process target = pb.start();

    try {

      waitForReady(target);

      HotSpotVirtualMachine vm = (HotSpotVirtualMachine)VirtualMachine.attach(((Integer)pid).toString());

      // First set the value.

      BufferedReader remoteDataReader = new BufferedReader(new InputStreamReader(

          vm.setFlag(flagName, flagValue)));

      String line;

      while((line = remoteDataReader.readLine()) != null) {

        System.out.println("setFlag: " + line);

        // Just empty the stream.

      }

      remoteDataReader.close();

      // Then read and make sure we get back the set value.

      remoteDataReader = new BufferedReader(new InputStreamReader(vm.printFlag(flagName)));

      boolean foundExpectedLine = false;

      line = null;

      while((line = remoteDataReader.readLine()) != null) {

        System.out.println("getFlag: " + line);

        if (line.equals("-XX:" + flagName + "=" + flagValue)) {

          foundExpectedLine = true;

        }

      }

      Asserts.assertTrue(foundExpectedLine, "Didn't get the expected output: '-XX:" + flagName + "=" + flagValue + "'");

      vm.detach();

    } finally {

      target.destroy();

      target.waitFor();

    }

  }

  private static void waitForReady(Process target) throws Exception {

    InputStream os = target.getInputStream();

    try (BufferedReader reader = new BufferedReader(new InputStreamReader(os))) {

      String line;

      while ((line = reader.readLine()) != null) {

        if ("Ready".equals(line)) {

          return;

        }

      }

    }

  }

  public static class Target {

    public static void main(String [] args) throws Exception {

      System.out.println("Ready");

      System.out.flush();

      while (true) {

        Thread.sleep(1000);

      }

    }

  }

}