YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

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//   http://www.apache.org/licenses/LICENSE-2.0

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// The following only applies to changes made to this file as part of YugaByte development.

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// Portions Copyright (c) YugaByte, Inc.

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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

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// http://www.apache.org/licenses/LICENSE-2.0

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// Unless required by applicable law or agreed to in writing, software distributed under the License

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#include <atomic>

#include <string>

#include <gtest/gtest.h>

#include "yb/util/countdown_latch.h"

#include "yb/util/test_macros.h"

#include "yb/util/thread.h"

#include "yb/util/threadpool.h"

namespace yb {

static void DecrementLatch(CountDownLatch* latch, int amount) {

  if (amount == 1) {

    latch->CountDown();

    return;

  }

  latch->CountDown(amount);

}

// Tests that we can decrement the latch by arbitrary amounts, as well

// as 1 by one.

TEST(TestCountDownLatch, TestLatch) {

  std::unique_ptr<ThreadPool> pool;

  ASSERT_OK(ThreadPoolBuilder("cdl-test").set_max_threads(1).Build(&pool));

  CountDownLatch latch(1000);

  // Decrement the count by 1 in another thread, this should not fire the

  // latch.

  ASSERT_OK(pool->SubmitFunc(std::bind(DecrementLatch, &latch, 1)));

  ASSERT_FALSE(latch.WaitFor(MonoDelta::FromMilliseconds(1000)));

  ASSERT_EQ(999, latch.count());

  // Now decrement by 1000 this should decrement to 0 and fire the latch

  // (even though 1000 is one more than the current count).

  ASSERT_OK(pool->SubmitFunc(std::bind(DecrementLatch, &latch, 1000)));

  latch.Wait();

  ASSERT_EQ(0, latch.count());

}

// Test that resetting to zero while there are waiters lets the waiters

// continue.

TEST(TestCountDownLatch, TestResetToZero) {

  CountDownLatch cdl(100);

  scoped_refptr<Thread> t;

  ASSERT_OK(Thread::Create("test", "cdl-test", &CountDownLatch::Wait, &cdl, &t));

  // Sleep for a bit until it's likely the other thread is waiting on the latch.

  SleepFor(MonoDelta::FromMilliseconds(10));

  cdl.Reset(0);

  t->Join();

}

} // namespace yb