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 * 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.

 *

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 */

import java.nio.ByteBuffer;

import java.util.List;

import java.util.Random;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CompletionStage;

import java.util.concurrent.Executor;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Flow;

import java.util.concurrent.Flow.Subscription;

import java.util.concurrent.SubmissionPublisher;

import java.util.function.BiConsumer;

import jdk.incubator.http.HttpResponse.BodyHandler;

import jdk.incubator.http.HttpResponse.BodySubscriber;

import jdk.test.lib.RandomFactory;

import org.testng.annotations.DataProvider;

import org.testng.annotations.Test;

import static java.lang.Long.MAX_VALUE;

import static java.lang.Long.min;

import static java.lang.System.out;

import static java.util.concurrent.CompletableFuture.delayedExecutor;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import static org.testng.Assert.*;

/*

 * @test

 * @bug 8184285

 * @summary Direct test for HttpResponse.BodySubscriber.buffering() API

 * @key randomness

 * @library /test/lib

 * @build jdk.test.lib.RandomFactory

 * @run testng/othervm -Djdk.internal.httpclient.debug=true BufferingSubscriberTest

 */

public class BufferingSubscriberTest {

    // If we compute that a test will take less that 10s

    // we judge it acceptable

    static final long LOWER_THRESHOLD = 10_000; // 10 sec.

    // If we compute that a test will take more than 20 sec

    // we judge it problematic: we will try to adjust the

    // buffer sizes, and if we can't we will print a warning

    static final long UPPER_THRESHOLD = 20_000; // 20 sec.

    static final Random random = RandomFactory.getRandom();

    static final long start = System.nanoTime();

    static final String START = "start";

    static final String END   = "end  ";

    static long elapsed() { return (System.nanoTime() - start)/1000_000;}

    static void printStamp(String what, String fmt, Object... args) {

        long elapsed = elapsed();

        long sec = elapsed/1000;

        long ms  = elapsed % 1000;

        String time = sec > 0 ? sec + "sec " : "";

        time = time + ms + "ms";

        out.println(what + "\t ["+time+"]\t "+ String.format(fmt,args));

    }

    @DataProvider(name = "negatives")

    public Object[][] negatives() {

        return new Object[][] {  { 0 }, { -1 }, { -1000 } };

    }

    @Test(dataProvider = "negatives", expectedExceptions = IllegalArgumentException.class)

    public void subscriberThrowsIAE(int bufferSize) {

        printStamp(START, "subscriberThrowsIAE(%d)", bufferSize);

        try {

            BodySubscriber<?> bp = BodySubscriber.asByteArray();

            BodySubscriber.buffering(bp, bufferSize);

        } finally {

            printStamp(END, "subscriberThrowsIAE(%d)", bufferSize);

        }

    }

    @Test(dataProvider = "negatives", expectedExceptions = IllegalArgumentException.class)

    public void handlerThrowsIAE(int bufferSize) {

        printStamp(START, "handlerThrowsIAE(%d)", bufferSize);

        try {

            BodyHandler<?> bp = BodyHandler.asByteArray();

            BodyHandler.buffering(bp, bufferSize);

        } finally {

            printStamp(END, "handlerThrowsIAE(%d)", bufferSize);

        }

    }

    // ---

    @DataProvider(name = "config")

    public Object[][] config() {

        return new Object[][] {

            // iterations delayMillis numBuffers bufferSize maxBufferSize minBufferSize

            { 1,              0,          1,         1,         2,            1   },

            { 1,              5,          1,         100,       2,            1   },

            { 1,              0,          1,         10,        1000,         1   },

            { 1,              10,         1,         10,        1000,         1   },

            { 1,              0,          1,         1000,      1000,         10  },

            { 1,              0,          10,        1000,      1000,         50  },

            { 1,              0,          1000,      10 ,       1000,         50  },

            { 1,              100,        1,         1000 * 4,  1000,         50  },

            { 100,            0,          1000,      1,         2,            1   },

            { 3,              0,          4,         5006,      1000,         50  },

            { 20,             0,          100,       4888,      1000,         100 },

            { 16,             10,         1000,      50 ,       1000,         100 },

            { 16,             10,         1000,      50 ,       657,          657 },

        };

    }

    @Test(dataProvider = "config")

    public void test(int iterations,

                     int delayMillis,

                     int numBuffers,

                     int bufferSize,

                     int maxBufferSize,

                     int minbufferSize) {

        for (long perRequestAmount : new long[] { 1L, MAX_VALUE })

            test(iterations,

                 delayMillis,

                 numBuffers,

                 bufferSize,

                 maxBufferSize,

                 minbufferSize,

                 perRequestAmount);

    }

    volatile boolean onNextThrew;

    BiConsumer<Flow.Subscriber<?>, ? super Throwable> onNextThrowHandler =

            (sub, ex) -> {

                onNextThrew = true;

                System.out.println("onNext threw " + ex);

                ex.printStackTrace();

    };

    public void test(int iterations,

                     int delayMillis,

                     int numBuffers,

                     int bufferSize,

                     int maxBufferSize,

                     int minBufferSize,

                     long requestAmount) {

        ExecutorService executor = Executors.newFixedThreadPool(1);

        try {

            out.printf("Iterations %d\n", iterations);

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

                printStamp(START, "Iteration %d", i);

                try {

                    SubmissionPublisher<List<ByteBuffer>> publisher =

                            new SubmissionPublisher<>(executor,

                                                      onNextThrowHandler);

                    CompletableFuture<?> cf = sink(publisher,

                            delayMillis,

                            numBuffers * bufferSize,

                            requestAmount,

                            maxBufferSize,

                            minBufferSize);

                    source(publisher, numBuffers, bufferSize);

                    publisher.close();

                    cf.join();

                } finally {

                    printStamp(END, "Iteration %d\n", i);

                }

            }

            assertFalse(onNextThrew, "Unexpected onNextThrew, check output");

            out.println("OK");

        } finally {

            executor.shutdown();

        }

    }

    static long accumulatedDataSize(List<ByteBuffer> bufs) {

        return bufs.stream().mapToLong(ByteBuffer::remaining).sum();

    }

    /** Returns a new BB with its contents set to monotonically increasing

     * values, staring at the given start index and wrapping every 100. */

    static ByteBuffer allocateBuffer(int size, int startIdx) {

        ByteBuffer b = ByteBuffer.allocate(size);

        for (int i=0; i<size; i++)

            b.put((byte)((startIdx + i) % 100));

        b.position(0);

        return b;

    }

    static class TestSubscriber implements BodySubscriber<Integer> {

        final int delayMillis;

        final int bufferSize;

        final int expectedTotalSize;

        final long requestAmount;

        final CompletableFuture<Integer> completion;

        final Executor delayedExecutor;

        volatile Flow.Subscription subscription;

        TestSubscriber(int bufferSize,

                       int delayMillis,

                       int expectedTotalSize,

                       long requestAmount) {

            this.bufferSize = bufferSize;

            this.completion = new CompletableFuture<>();

            this.delayMillis = delayMillis;

            this.delayedExecutor = delayedExecutor(delayMillis, MILLISECONDS);

            this.expectedTotalSize = expectedTotalSize;

            this.requestAmount = requestAmount;

        }

        /**

         * Example of a factory method which would decorate a buffering

         * subscriber to create a new subscriber dependent on buffering capability.

         * <p>

         * The integer type parameter simulates the body just by counting the

         * number of bytes in the body.

         */

        static BodySubscriber<Integer> createSubscriber(int bufferSize,

                                                        int delay,

                                                        int expectedTotalSize,

                                                        long requestAmount) {

            TestSubscriber s = new TestSubscriber(bufferSize,

                                                delay,

                                                expectedTotalSize,

                                                requestAmount);

            return BodySubscriber.buffering(s, bufferSize);

        }

        private void requestMore() {

            subscription.request(requestAmount);

        }

        @Override

        public void onSubscribe(Subscription subscription) {

            assertNull(this.subscription);

            this.subscription = subscription;

            if (delayMillis > 0)

                delayedExecutor.execute(this::requestMore);

            else

                requestMore();

        }

        volatile int wrongSizes;

        volatile int totalBytesReceived;

        volatile int onNextInvocations;

        volatile long lastSeenSize = -1;

        volatile boolean noMoreOnNext; // false

        volatile int index; // 0

        volatile long count;

        @Override

        public void onNext(List<ByteBuffer> items) {

            try {

                long sz = accumulatedDataSize(items);

                boolean printStamp = delayMillis > 0

                        && requestAmount < Long.MAX_VALUE

                        && count % 20 == 0;

                if (printStamp) {

                    printStamp("stamp", "count=%d sz=%d accumulated=%d",

                            count, sz, (totalBytesReceived + sz));

                }

                count++;

                onNextInvocations++;

                assertNotEquals(sz, 0L, "Unexpected empty buffers");

                items.stream().forEach(b -> assertEquals(b.position(), 0));

                assertFalse(noMoreOnNext);

                if (sz != bufferSize) {

                    String msg = sz + ", should be less than bufferSize, " + bufferSize;

                    assertTrue(sz < bufferSize, msg);

                    assertTrue(lastSeenSize == -1 || lastSeenSize == bufferSize);

                    noMoreOnNext = true;

                    wrongSizes++;

                    printStamp("onNext",

                            "Possibly received last buffer: sz=%d, accumulated=%d, total=%d",

                            sz, totalBytesReceived, totalBytesReceived + sz);

                } else {

                    assertEquals(sz, bufferSize, "Expected to receive exactly bufferSize");

                }

                lastSeenSize = sz;

                // Ensure expected contents

                for (ByteBuffer b : items) {

                    while (b.hasRemaining()) {

                        assertEquals(b.get(), (byte) (index % 100));

                        index++;

                    }

                }

                totalBytesReceived += sz;

                assertEquals(totalBytesReceived, index);

                if (delayMillis > 0 && ((expectedTotalSize - totalBytesReceived) > bufferSize))

                    delayedExecutor.execute(this::requestMore);

                else

                    requestMore();

            } catch (Throwable t) {

                completion.completeExceptionally(t);

            }

        }

        @Override

        public void onError(Throwable throwable) {

            completion.completeExceptionally(throwable);

        }

        @Override

        public void onComplete() {

            if (wrongSizes > 1) { // allow just the final item to be smaller

                String msg = "Wrong sizes. Expected no more than 1. [" + this + "]";

                completion.completeExceptionally(new Throwable(msg));

            }

            if (totalBytesReceived != expectedTotalSize) {

                String msg = "Wrong number of bytes. [" + this + "]";

                completion.completeExceptionally(new Throwable(msg));

            } else {

                completion.complete(totalBytesReceived);

            }

        }

        @Override

        public CompletionStage<Integer> getBody() {

            return completion;

        }

        @Override

        public String toString() {

            StringBuilder sb = new StringBuilder();

            sb.append(super.toString());

            sb.append(", bufferSize=").append(bufferSize);

            sb.append(", onNextInvocations=").append(onNextInvocations);

            sb.append(", totalBytesReceived=").append(totalBytesReceived);

            sb.append(", expectedTotalSize=").append(expectedTotalSize);

            sb.append(", requestAmount=").append(requestAmount);

            sb.append(", lastSeenSize=").append(lastSeenSize);

            sb.append(", wrongSizes=").append(wrongSizes);

            sb.append(", index=").append(index);

            return sb.toString();

        }

    }

    /**

     * Publishes data, through the given publisher, using the main thread.

     *

     * Note: The executor supplied when creating the SubmissionPublisher provides

     * the threads for executing the Subscribers.

     *

     * @param publisher the publisher

     * @param numBuffers the number of buffers to send ( before splitting in two )

     * @param bufferSize the total size of the data to send ( before splitting in two )

     */

    static void source(SubmissionPublisher<List<ByteBuffer>> publisher,

                       int numBuffers,

                       int bufferSize) {

        printStamp("source","Publishing %d buffers of size %d each", numBuffers, bufferSize);

        int index = 0;

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

            int chunkSize = random.nextInt(bufferSize);

            ByteBuffer buf1 = allocateBuffer(chunkSize, index);

            index += chunkSize;

            ByteBuffer buf2 = allocateBuffer(bufferSize - chunkSize, index);

            index += bufferSize - chunkSize;

            publisher.submit(List.of(buf1, buf2));

        }

        printStamp("source", "complete");

    }

    /**

     * Creates and subscribes Subscribers that receive data from the given

     * publisher.

     *

     * @param publisher the publisher

     * @param delayMillis time, in milliseconds, to delay the Subscription

     *                    requesting more bytes ( for simulating slow consumption )

     * @param expectedTotalSize the total number of bytes expected to be received

     *                          by the subscribers

     * @return a CompletableFuture which completes when the subscription is complete

     */

    static CompletableFuture<?> sink(SubmissionPublisher<List<ByteBuffer>> publisher,

                                     int delayMillis,

                                     int expectedTotalSize,

                                     long requestAmount,

                                     int maxBufferSize,

                                     int minBufferSize) {

        int bufferSize = chooseBufferSize(maxBufferSize,

                                          minBufferSize,

                                          delayMillis,

                                          expectedTotalSize,

                                          requestAmount);

        assert bufferSize > 0;

        assert bufferSize >= minBufferSize;

        assert bufferSize <= maxBufferSize;

        BodySubscriber<Integer> sub = TestSubscriber.createSubscriber(bufferSize,

                                                                    delayMillis,

                                                                    expectedTotalSize,

                                                                    requestAmount);

        publisher.subscribe(sub);

        printStamp("sink","Subscriber reads data with buffer size: %d", bufferSize);

        out.printf("Subscription delay is %d msec\n", delayMillis);

        long delay = (((long)delayMillis * expectedTotalSize) / bufferSize) / requestAmount;

        out.printf("Minimum total delay is %d sec %d ms\n", delay / 1000, delay % 1000);

        out.printf("Request amount is %d items\n", requestAmount);

        return sub.getBody().toCompletableFuture();

    }

    static int chooseBufferSize(int maxBufferSize,

                                int minBufferSize,

                                int delaysMillis,

                                int expectedTotalSize,

                                long requestAmount) {

        assert minBufferSize > 0 && maxBufferSize > 0 && requestAmount > 0;

        int bufferSize = maxBufferSize == minBufferSize ? maxBufferSize :

                (random.nextInt(maxBufferSize - minBufferSize)

                    + minBufferSize);

        if (requestAmount == Long.MAX_VALUE) return bufferSize;

        long minDelay = (((long)delaysMillis * expectedTotalSize) / maxBufferSize)

                / requestAmount;

        long maxDelay = (((long)delaysMillis * expectedTotalSize) / minBufferSize)

                / requestAmount;

        // if the maximum delay is < 10s just take a random number between min and max.

        if (maxDelay <= LOWER_THRESHOLD) {

            return bufferSize;

        }

        // if minimum delay is greater than 20s then print a warning and use max buffer.

        if (minDelay >= UPPER_THRESHOLD) {

            System.out.println("Warning: minimum delay is "

                    + minDelay/1000 + "sec " + minDelay%1000 + "ms");

            System.err.println("Warning: minimum delay is "

                    + minDelay/1000 + "sec " + minDelay%1000 + "ms");

            return maxBufferSize;

        }

        // maxDelay could be anything, but minDelay is below the UPPER_THRESHOLD

        // try to pick up a buffer size that keeps the delay below the

        // UPPER_THRESHOLD

        while (minBufferSize < maxBufferSize) {

            bufferSize = random.nextInt(maxBufferSize - minBufferSize)

                    + minBufferSize;

            long delay = (((long)delaysMillis * expectedTotalSize) / bufferSize)

                    / requestAmount;

            if (delay < UPPER_THRESHOLD) return bufferSize;

            minBufferSize++;

        }

        return minBufferSize;

    }

    // ---

    /* Main entry point for standalone testing of the main functional test. */

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

        BufferingSubscriberTest t = new BufferingSubscriberTest();

        for (Object[] objs : t.config())

            t.test((int)objs[0], (int)objs[1], (int)objs[2], (int)objs[3], (int)objs[4], (int)objs[5]);

    }

}