third_party/WebKit/Source/web/tests/SpinLockTest.cpp

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#include "wtf/SpinLock.h"

#include "platform/ThreadSafeFunctional.h"
#include "public/platform/Platform.h"
#include "public/platform/WebTaskRunner.h"
#include "public/platform/WebThread.h"
#include "public/platform/WebTraceLocation.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassOwnPtr.h"

namespace blink {

static const size_t bufferSize = 16;

static SpinLock lock;

static void fillBuffer(volatile char* buffer, char fillPattern)
{
    for (size_t i = 0; i < bufferSize; ++i)
        buffer[i] = fillPattern;
}

static void changeAndCheckBuffer(volatile char* buffer)
{
    fillBuffer(buffer, '\0');
    int total = 0;
    for (size_t i = 0; i < bufferSize; ++i)
        total += buffer[i];

    EXPECT_EQ(0, total);

    // This will mess with the other thread's calculation if we accidentally get
    // concurrency.
    fillBuffer(buffer, '!');
}

static void threadMain(volatile char* buffer)
{
    for (int i = 0; i < 500000; ++i) {
        SpinLock::Guard guard(lock);
        changeAndCheckBuffer(buffer);
    }
}

TEST(SpinLockTest, Torture)
{
    char sharedBuffer[bufferSize];

    OwnPtr<WebThread> thread1 = adoptPtr(Platform::current()->createThread("thread1"));
    OwnPtr<WebThread> thread2 = adoptPtr(Platform::current()->createThread("thread2"));

    thread1->getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&threadMain, AllowCrossThreadAccess(static_cast<char*>(sharedBuffer))));
    thread2->getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&threadMain, AllowCrossThreadAccess(static_cast<char*>(sharedBuffer))));

    thread1.clear();
    thread2.clear();
}

} // namespace blink