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

/*
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#include "platform/wtf/SpinLock.h"

#include <memory>
#include "platform/CrossThreadFunctional.h"
#include "platform/WebTaskRunner.h"
#include "platform/wtf/PtrUtil.h"
#include "public/platform/Platform.h"
#include "public/platform/WebThread.h"
#include "public/platform/WebTraceLocation.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace blink {

static const size_t kBufferSize = 16;

static SpinLock g_lock;

static void FillBuffer(volatile char* buffer, char fill_pattern) {
  for (size_t i = 0; i < kBufferSize; ++i)
    buffer[i] = fill_pattern;
}

static void ChangeAndCheckBuffer(volatile char* buffer) {
  FillBuffer(buffer, '\0');
  int total = 0;
  for (size_t i = 0; i < kBufferSize; ++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(g_lock);
    ChangeAndCheckBuffer(buffer);
  }
}

TEST(SpinLockTest, Torture) {
  char shared_buffer[kBufferSize];

  std::unique_ptr<WebThread> thread1 =
      Platform::Current()->CreateThread("thread1");
  std::unique_ptr<WebThread> thread2 =
      Platform::Current()->CreateThread("thread2");

  thread1->GetWebTaskRunner()->PostTask(
      BLINK_FROM_HERE,
      CrossThreadBind(&ThreadMain, CrossThreadUnretained(
                                       static_cast<char*>(shared_buffer))));
  thread2->GetWebTaskRunner()->PostTask(
      BLINK_FROM_HERE,
      CrossThreadBind(&ThreadMain, CrossThreadUnretained(
                                       static_cast<char*>(shared_buffer))));

  thread1.reset();
  thread2.reset();
}

}  // namespace blink