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package jdk.jfr.event.io;

import java.io.File;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.time.Duration;

import java.time.Instant;

import java.util.ArrayList;

import java.util.Comparator;

import java.util.List;

import jdk.jfr.Recording;

import jdk.jfr.consumer.RecordedEvent;

import jdk.test.lib.Asserts;

import jdk.test.lib.jfr.Events;

import jdk.test.lib.thread.TestThread;

import jdk.test.lib.thread.XRun;

 * @test

 * @summary Verify the event time stamp and thread name

 * @key jfr

 * @library /test/lib /test/jdk

 * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:-UseFastUnorderedTimeStamps jdk.jfr.event.io.TestRandomAccessFileThread

 */

// TODO: This test should work without -XX:-UseFastUnorderedTimeStamps

// The test uses 2 threads to read and write to a file.

// The number of bytes in each read/write operation is increased by 1.

// By looking at the number of bytes in each event, we know in what order

// the events should arrive. This is used to verify the event time stamps.

public class TestRandomAccessFileThread {

    private static final int OP_COUNT = 100;    // Total number of read/write operations.

    private static volatile int writeCount = 0; // Number of writes executed.

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

        File tmp = File.createTempFile("TestRandomAccessFileThread", ".tmp", new File("."));

        tmp.deleteOnExit();

        Recording recording = new Recording();

        recording.enable(IOEvent.EVENT_FILE_READ).withThreshold(Duration.ofMillis(0));

        recording.enable(IOEvent.EVENT_FILE_WRITE).withThreshold(Duration.ofMillis(0));

        recording.start();

        TestThread writerThread = new TestThread(new XRun() {

            @Override

            public void xrun() throws IOException {

                final byte[] buf = new byte[OP_COUNT];

                for (int i = 0; i < buf.length; ++i) {

                    buf[i] = (byte)((i + 'a') % 255);

                }

                try (RandomAccessFile raf = new RandomAccessFile(tmp, "rwd")) {

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

                        raf.write(buf, 0, i + 1);

                        writeCount++;

                    }

                }

            }}, "TestWriterThread");

            TestThread readerThread = new TestThread(new XRun() {

            @Override

            public void xrun() throws IOException {

                try (RandomAccessFile raf = new RandomAccessFile(tmp, "r")) {

                    byte[] buf = new byte[OP_COUNT];

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

                        while (writeCount <= i) {

                            // No more data to read. Wait for writer thread.

                            Thread.yield();

                        }

                        int expectedSize = i + 1;

                        int actualSize = raf.read(buf, 0, expectedSize);

                        Asserts.assertEquals(actualSize, expectedSize, "Wrong read size. Probably test error.");

                    }

                }

            }}, "TestReaderThread");

            readerThread.start();

            writerThread.start();

            writerThread.joinAndThrow();

            readerThread.joinAndThrow();

            recording.stop();

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

            events.sort(new EventComparator());

            List<RecordedEvent> readEvents = new ArrayList<>();

            List<RecordedEvent> writeEvents = new ArrayList<>();

            for (RecordedEvent event : events) {

                if (!isOurEvent(event, tmp)) {

                    continue;

                }

                logEventSummary(event);

                if (Events.isEventType(event,IOEvent.EVENT_FILE_READ)) {

                    readEvents.add(event);

                } else {

                    writeEvents.add(event);

                }

            }

            verifyThread(readEvents, readerThread);

            verifyThread(writeEvents, writerThread);

            verifyBytes(readEvents, "bytesRead");

            verifyBytes(writeEvents, "bytesWritten");

            verifyTimes(readEvents);

            verifyTimes(writeEvents);

            verifyReadWriteTimes(readEvents, writeEvents);

            Asserts.assertEquals(readEvents.size(), OP_COUNT, "Wrong number of read events");

            Asserts.assertEquals(writeEvents.size(), OP_COUNT, "Wrong number of write events");

        }

        private static void logEventSummary(RecordedEvent event) {

            boolean isRead = Events.isEventType(event, IOEvent.EVENT_FILE_READ);

            String name = isRead ? "read " : "write";

            String bytesField = isRead ? "bytesRead" : "bytesWritten";

            long bytes = Events.assertField(event, bytesField).getValue();

            long commit = Events.assertField(event, "startTime").getValue();

            Instant start = event.getStartTime();

            Instant end = event.getEndTime();

            System.out.printf("%s: bytes=%d, commit=%d, start=%s, end=%s%n", name, bytes, commit, start, end);

        }

        private static void verifyThread(List<RecordedEvent> events, Thread thread) {

            events.stream().forEach(e -> Events.assertEventThread(e, thread));

        }

        private static void verifyBytes(List<RecordedEvent> events, String fieldName) {

            long expectedBytes = 0;

            for (RecordedEvent event : events) {

                Events.assertField(event, fieldName).equal(++expectedBytes);

            }

        }

        // Verify that all times are increasing

        private static void verifyTimes(List<RecordedEvent> events) {

            RecordedEvent prev = null;

            for (RecordedEvent curr : events) {

                if (prev != null) {

                    try {

                        Asserts.assertGreaterThanOrEqual(curr.getStartTime(), prev.getStartTime(), "Wrong startTime");

                        Asserts.assertGreaterThanOrEqual(curr.getEndTime(), prev.getEndTime(), "Wrong endTime");

                        long commitPrev = Events.assertField(prev, "startTime").getValue();

                        long commitCurr = Events.assertField(curr, "startTime").getValue();

                        Asserts.assertGreaterThanOrEqual(commitCurr, commitPrev, "Wrong commitTime");

                    } catch (Exception e) {

                        System.out.println("Error: " + e.getMessage());

                        System.out.println("Prev Event: " + prev);

                        System.out.println("Curr Event: " + curr);

                        throw e;

                    }

                }

                prev = curr;

            }

        }

        // Verify that all times are increasing

        private static void verifyReadWriteTimes(List<RecordedEvent> readEvents, List<RecordedEvent> writeEvents) {

            List<RecordedEvent> events = new ArrayList<>();

            events.addAll(readEvents);

            events.addAll(writeEvents);

            events.sort(new EventComparator());

            int countRead = 0;

            int countWrite = 0;

            for (RecordedEvent event : events) {

                if (Events.isEventType(event, IOEvent.EVENT_FILE_READ)) {

                    ++countRead;

                } else {

                    ++countWrite;

                }

                // We can not read from the file before it has been written.

                // This check verifies that times of different threads are correct.

                // Since the read and write are from different threads, it is possible that the read

                // is committed before the same write.

                // But read operation may only be 1 step ahead of the write operation.

                Asserts.assertLessThanOrEqual(countRead, countWrite + 1, "read must be after write");

            }

        }

        private static boolean isOurEvent(RecordedEvent event, File file) {

            if (!Events.isEventType(event, IOEvent.EVENT_FILE_READ) &&

                !Events.isEventType(event, IOEvent.EVENT_FILE_WRITE)) {

                return false;

            }

            String path = Events.assertField(event, "path").getValue();

            return file.getPath().equals(path);

        }

        private static class EventComparator implements Comparator<RecordedEvent> {

            @Override

            public int compare(RecordedEvent a, RecordedEvent b) {

                long commitA = Events.assertField(a, "startTime").getValue();

                long commitB = Events.assertField(b, "startTime").getValue();

                return Long.compare(commitA, commitB);

            }

        }

}