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package jdk.jfr.event.gc.detailed;

import static jdk.test.lib.Asserts.assertEquals;

import static jdk.test.lib.Asserts.assertNotEquals;

import static jdk.test.lib.Asserts.assertNotNull;

import static jdk.test.lib.Asserts.assertTrue;

import java.lang.management.GarbageCollectorMXBean;

import java.lang.management.ManagementFactory;

import java.util.List;

import java.util.concurrent.ThreadLocalRandom;

import jdk.jfr.Recording;

import jdk.jfr.consumer.RecordedEvent;

import jdk.test.lib.jfr.EventNames;

import jdk.test.lib.jfr.Events;

/**

 * This is a base class for testing Promotion Events

 *

 * See TestPromotionEventWith* for actual test classes. Tests must set

 * -XX:MaxTenuringThreshold=5 -XX:InitialTenuringThreshold=5

 *

 * @author Staffan Friberg

 */

public class PromotionEvent {

    private final static String PROMOTION_IN_NEW_PLAB_NAME = EventNames.PromoteObjectInNewPLAB;

    private final static String PROMOTION_OUTSIDE_PLAB_NAME = EventNames.PromoteObjectOutsidePLAB;

    // This value needs to match the command line option set above

    private final static int MAX_TENURING_THRESHOLD = 5;

    // Keep track of the collection count just before and after JFR recording

    private static int startGCCount = 0;

    // Dummy objects to keep things alive and assure allocation happens

    public static Object dummy;

    public static Object[] keepAlive = new Object[128];

    public static Object[] age = new Object[128];

    public static void test() throws Exception {

        GarbageCollectorMXBean ycBean = null;

        List<GarbageCollectorMXBean> gcBeans = ManagementFactory.getGarbageCollectorMXBeans();

        for (GarbageCollectorMXBean gcBean : gcBeans) {

            if ("PS Scavenge".equals(gcBean.getName())

                ycBean = gcBean;

            }

            if (ycBean != null) {

                break;

            }

        }

        if (ycBean == null) {

            assertNotNull(ycBean, "Test failed since the MXBean for the Young Collector could not be found.");

            return; // To remove IDE warning

        }

        System.gc(); // Clear nusery before recording

        // Get total GC count before recording

        for (GarbageCollectorMXBean gcBean : gcBeans) {

            startGCCount += gcBean.getCollectionCount();

        }

        Recording recording = new Recording();

        recording.enable(PROMOTION_IN_NEW_PLAB_NAME);

        recording.enable(PROMOTION_OUTSIDE_PLAB_NAME);

        recording.start();

        byte[] largeBytes = new byte[1024 * 10];

        byte[] smallBytes = new byte[64];

        // Some large strings to keep alive for tenuring

        for (int i = 0; i < keepAlive.length / 2; i++) {

            ThreadLocalRandom.current().nextBytes(largeBytes);

            keepAlive[i] = new String(largeBytes);

        }

        // Some small strings to keep alive for tenuring

        for (int i = keepAlive.length / 2; i < keepAlive.length; i++) {

            ThreadLocalRandom.current().nextBytes(smallBytes);

            keepAlive[i] = new String(smallBytes);

        }

        // Allocate temp data to force GCs until we have promoted the live data

        for (int gcCount = 0; gcCount < MAX_TENURING_THRESHOLD * 2; gcCount++) {

            long currentGCCount = ycBean.getCollectionCount();

            // some large strings to age

            for (int i = 0; i < age.length / 2; i++) {

                ThreadLocalRandom.current().nextBytes(largeBytes);

                age[i] = new String(largeBytes);

            }

            // Some small strings to age

            for (int i = age.length / 2; i < age.length; i++) {

                ThreadLocalRandom.current().nextBytes(smallBytes);

                age[i] = new String(smallBytes);

            }

            while (ycBean.getCollectionCount() <= currentGCCount + 3) {

                ThreadLocalRandom.current().nextBytes(smallBytes);

                dummy = new String(smallBytes);

            }

        }

        recording.stop();

        List<RecordedEvent> events = Events.fromRecording(recording);

        verifyPromotionSampleEvents(events);

        recording.close();

    }

    private static void verifyPromotionSampleEvents(List<RecordedEvent> events)

            throws Exception {

        boolean objectWasPromotedInNewPLAB = false;

        boolean objectPromotedInNewPLABWasAged = false;

        boolean objectPromotedInNewPLABWasTenured = false;

        boolean objectWasPromotedOutsidePLAB = false;

        boolean objectPromotedOutsidePLABWasAged = false;

        boolean objectPromotedOutsidePLABWasTenured = false;

        Events.hasEvents(events);

        for (RecordedEvent event : events) {

            // Read all common fields

            Events.assertField(event, "gcId").atLeast(startGCCount).getValue();

            String className = (event.getEventType()).getName().toString();

            Events.assertField(event, "tenuringAge").atLeast(0).atMost(MAX_TENURING_THRESHOLD).getValue();

            Boolean tenured = Events.assertField(event, "tenured").getValue();

            Long objectSize = Events.assertField(event, "objectSize").above(0L).getValue();

            // Verify Class Name

            assertNotNull(className, "Class name is null. Event: " + event);

            assertNotEquals(className.length(), 0, "Class name is of zero length. Event: " + event);

            // Verify PLAB size and direct allocation

            if (PROMOTION_IN_NEW_PLAB_NAME.equals(event.getEventType().getName())) {

                // Read event specific fields

                Long plabSize = Events.assertField(event, "plabSize").above(0L).getValue();

                assertTrue(plabSize >= objectSize, "PLAB size is smaller than object size. Event: " + event);

                objectWasPromotedInNewPLAB = true;

                // Verify tenured is hard to do as objects might be tenured earlier than the max threshold

                // but at least verify that we got the field set at least once during the test

                if (tenured) {

                    objectPromotedInNewPLABWasTenured = true;

                } else {

                    objectPromotedInNewPLABWasAged = true;

                }

            } else if (PROMOTION_OUTSIDE_PLAB_NAME.equals(event.getEventType().getName())) {

                objectWasPromotedOutsidePLAB = true;

                // Verify tenured is hard to do as objects might be tenured earlier than the max threshold

                // but at least verify that we got the field set at least once during the test

                if (tenured) {

                    objectPromotedOutsidePLABWasTenured = true;

                } else {

                    objectPromotedOutsidePLABWasAged = true;

                }

            } else {

                assertEquals(event.getEventType().getName(), "Unreachable...", "Got wrong type of event " + event);

            }

        }

        // Verify that at least one event of these types occured during test

        assertTrue(objectWasPromotedInNewPLAB, "No object in new plab was promoted in test");

        assertTrue(objectPromotedInNewPLABWasAged, "No object in new plab was aged in test");

        assertTrue(objectPromotedInNewPLABWasTenured, "No object in new plab was tenured in test");

        assertTrue(objectWasPromotedOutsidePLAB, "No object outside plab was promoted in test");

        assertTrue(objectPromotedOutsidePLABWasAged, "No object outside plab was aged in test");

        assertTrue(objectPromotedOutsidePLABWasTenured, "No object outside plab was tenured in test");

    }

}