
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "platform/Timer.h"

#include "base/message_loop/message_loop.h"
#include "base/time/time.h"
#include "platform/testing/UnitTestHelpers.h"
#include "public/platform/Platform.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/PtrUtil.h"
#include "wtf/Vector.h"

namespace blink {

class TimerPerfTest : public ::testing::Test {
public:
    void nopTask(TimerBase*)
    {
    }

    void recordStartRunTime(TimerBase*)
    {
        m_runStart = base::ThreadTicks::Now();
    }

    void recordEndRunTime(TimerBase*)
    {
        m_runEnd = base::ThreadTicks::Now();
        base::MessageLoop::current()->QuitNow();
    }

    base::ThreadTicks m_runStart;
    base::ThreadTicks m_runEnd;
};

TEST_F(TimerPerfTest, PostAndRunTimers)
{
    const int numIterations = 10000;
    Vector<std::unique_ptr<Timer<TimerPerfTest>>> timers(numIterations);
    for (int i = 0; i < numIterations; i++) {
        timers[i].reset(new Timer<TimerPerfTest>(this, &TimerPerfTest::nopTask));
    }

    Timer<TimerPerfTest> measureRunStart(this, &TimerPerfTest::recordStartRunTime);
    Timer<TimerPerfTest> measureRunEnd(this, &TimerPerfTest::recordEndRunTime);

    measureRunStart.startOneShot(0.0, BLINK_FROM_HERE);
    base::ThreadTicks postStart = base::ThreadTicks::Now();
    for (int i = 0; i < numIterations; i++) {
        timers[i]->startOneShot(0.0, BLINK_FROM_HERE);
    }
    base::ThreadTicks postEnd = base::ThreadTicks::Now();
    measureRunEnd.startOneShot(0.0, BLINK_FROM_HERE);

    testing::enterRunLoop();

    double postingTime = (postEnd - postStart).InMicroseconds();
    double postingTimeUsPerCall = postingTime / static_cast<double>(numIterations);
    LOG(INFO) << "TimerBase::startOneShot cost (us/call) " << postingTimeUsPerCall << " (total " << postingTime << " us)";
    LOG(INFO) << "Time to run " << numIterations << " trivial tasks (us) " << (m_runEnd - m_runStart).InMicroseconds();
}

TEST_F(TimerPerfTest, PostThenCancelTenThousandTimers)
{
    const int numIterations = 10000;
    Vector<std::unique_ptr<Timer<TimerPerfTest>>> timers(numIterations);
    for (int i = 0; i < numIterations; i++) {
        timers[i].reset(new Timer<TimerPerfTest>(this, &TimerPerfTest::nopTask));
    }

    Timer<TimerPerfTest> measureRunStart(this, &TimerPerfTest::recordStartRunTime);
    Timer<TimerPerfTest> measureRunEnd(this, &TimerPerfTest::recordEndRunTime);

    measureRunStart.startOneShot(0.0, BLINK_FROM_HERE);
    base::ThreadTicks postStart = base::ThreadTicks::Now();
    for (int i = 0; i < numIterations; i++) {
        timers[i]->startOneShot(0.0, BLINK_FROM_HERE);
    }
    base::ThreadTicks postEnd = base::ThreadTicks::Now();
    measureRunEnd.startOneShot(0.0, BLINK_FROM_HERE);

    base::ThreadTicks cancelStart = base::ThreadTicks::Now();
    for (int i = 0; i < numIterations; i++) {
        timers[i]->stop();
    }
    base::ThreadTicks cancelEnd = base::ThreadTicks::Now();

    testing::enterRunLoop();

    double postingTime = (postEnd - postStart).InMicroseconds();
    double postingTimeUsPerCall = postingTime / static_cast<double>(numIterations);
    LOG(INFO) << "TimerBase::startOneShot cost (us/call) " << postingTimeUsPerCall << " (total " << postingTime << " us)";

    double cancelTime = (cancelEnd - cancelStart).InMicroseconds();
    double cancelTimeUsPerCall = cancelTime / static_cast<double>(numIterations);
    LOG(INFO) << "TimerBase::stop cost (us/call) " << cancelTimeUsPerCall << " (total " << cancelTime << " us)";
    LOG(INFO) << "Time to run " << numIterations << " canceled tasks (us) " << (m_runEnd - m_runStart).InMicroseconds();
}

} // namespace blink