namespace Fifo
{
static constexpr u32 FIFO_SIZE = 2 * 1024 * 1024;
static constexpr int GPU_TIME_SLOT_SIZE = 1000;

static Common::BlockingLoop s_gpu_mainloop;

static Common::Flag s_emu_running_state;

// Most of this array is unlikely to be faulted in...
static u8 s_fifo_aux_data[FIFO_SIZE];
static u8* s_fifo_aux_write_ptr;
static u8* s_fifo_aux_read_ptr;

// This could be in SConfig, but it depends on multiple settings
// and can change at runtime.
static bool s_use_deterministic_gpu_thread;

static CoreTiming::EventType* s_event_sync_gpu;

// STATE_TO_SAVE
static u8* s_video_buffer;
static u8* s_video_buffer_read_ptr;
static std::atomic<u8*> s_video_buffer_write_ptr;
static std::atomic<u8*> s_video_buffer_seen_ptr;
static u8* s_video_buffer_pp_read_ptr;
// The read_ptr is always owned by the GPU thread.  In normal mode, so is the
// write_ptr, despite it being atomic.  In deterministic GPU thread mode,
// things get a bit more complicated:
// - The seen_ptr is written by the GPU thread, and points to what it's already
// processed as much of as possible - in the case of a partial command which
// caused it to stop, not the same as the read ptr.  It's written by the GPU,
// under the lock, and updating the cond.
// - The write_ptr is written by the CPU thread after it copies data from the
// FIFO.  Maybe someday it will be under the lock.  For now, because RunGpuLoop
// polls, it's just atomic.
// - The pp_read_ptr is the CPU preprocessing version of the read_ptr.

static std::atomic<int> s_sync_ticks;
static bool s_syncing_suspended;
static Common::Event s_sync_wakeup_event;

void DoState(PointerWrap& p)
{
  p.DoArray(s_video_buffer, FIFO_SIZE);
  u8* write_ptr = s_video_buffer_write_ptr;
  p.DoPointer(write_ptr, s_video_buffer);
  s_video_buffer_write_ptr = write_ptr;
  p.DoPointer(s_video_buffer_read_ptr, s_video_buffer);
  if (p.mode == PointerWrap::MODE_READ && s_use_deterministic_gpu_thread)
  {
    // We're good and paused, right?
    s_video_buffer_seen_ptr = s_video_buffer_pp_read_ptr = s_video_buffer_read_ptr;
  }

  p.Do(s_sync_ticks);
  p.Do(s_syncing_suspended);
}

void PauseAndLock(bool doLock, bool unpauseOnUnlock)
{
  if (doLock)
  {
    SyncGPU(SyncGPUReason::Other);
    EmulatorState(false);

    const SConfig& param = SConfig::GetInstance();

    if (!param.bCPUThread || s_use_deterministic_gpu_thread)
      return;

    s_gpu_mainloop.WaitYield(std::chrono::milliseconds(100), Host_YieldToUI);
  }
  else
  {
    if (unpauseOnUnlock)
      EmulatorState(true);
  }
}

void Init()
{
  // Padded so that SIMD overreads in the vertex loader are safe
  s_video_buffer = static_cast<u8*>(Common::AllocateMemoryPages(FIFO_SIZE + 4));
  ResetVideoBuffer();
  if (SConfig::GetInstance().bCPUThread)
    s_gpu_mainloop.Prepare();
  s_sync_ticks.store(0);
}

void Shutdown()
{
  if (s_gpu_mainloop.IsRunning())
    PanicAlert("Fifo shutting down while active");

  Common::FreeMemoryPages(s_video_buffer, FIFO_SIZE + 4);
  s_video_buffer = nullptr;
  s_video_buffer_write_ptr = nullptr;
  s_video_buffer_pp_read_ptr = nullptr;
  s_video_buffer_read_ptr = nullptr;
//.........这里部分代码省略.........

u32 VideoBackendHardware::Video_AccessEFB(EFBAccessType type, u32 x, u32 y, u32 InputData)
{
	if (s_BackendInitialized && g_ActiveConfig.bEFBAccessEnable)
	{
		s_accessEFBArgs.type = type;
		s_accessEFBArgs.x = x;
		s_accessEFBArgs.y = y;
		s_accessEFBArgs.Data = InputData;

		s_efbAccessRequested.Set();

		if (SConfig::GetInstance().m_LocalCoreStartupParameter.bCPUThread)
		{
			s_efbAccessReadyEvent.Reset();
			if (s_FifoShuttingDown.IsSet())
				return 0;
			s_efbAccessRequested.Set();
			s_efbAccessReadyEvent.Wait();
		}
		else
			VideoFifo_CheckEFBAccess();

		return s_AccessEFBResult;
	}

	return 0;
}

static void DVDThread()
{
  Common::SetCurrentThreadName("DVD thread");

  while (true)
  {
    s_request_queue_expanded.Wait();

    if (s_dvd_thread_exiting.IsSet())
      return;

    ReadRequest request;
    while (s_request_queue.Pop(request))
    {
      FileMonitor::Log(*s_disc, request.partition, request.dvd_offset);

      std::vector<u8> buffer(request.length);
      if (!s_disc->Read(request.dvd_offset, request.length, buffer.data(), request.partition))
        buffer.resize(0);

      request.realtime_done_us = Common::Timer::GetTimeUs();

      s_result_queue.Push(ReadResult(std::move(request), std::move(buffer)));
      s_result_queue_expanded.Set();

      if (s_dvd_thread_exiting.IsSet())
        return;
    }
  }
}

static void VideoFifo_CheckPerfQueryRequest()
{
	if (s_perfQueryRequested.IsSet())
	{
		g_perf_query->FlushResults();
		s_perfQueryRequested.Clear();
		s_perfQueryReadyEvent.Set();
	}
}

void VideoFifo_CheckEFBAccess()
{
	if (s_efbAccessRequested.IsSet())
	{
		s_AccessEFBResult = g_renderer->AccessEFB(s_accessEFBArgs.type, s_accessEFBArgs.x, s_accessEFBArgs.y, s_accessEFBArgs.Data);
		s_efbAccessRequested.Clear();
		s_efbAccessReadyEvent.Set();
	}
}

// Run from the graphics thread (from Fifo.cpp)
static void VideoFifo_CheckSwapRequest()
{
	if (g_ActiveConfig.bUseXFB)
	{
		if (s_swapRequested.IsSet())
		{
			EFBRectangle rc;
			Renderer::Swap(s_beginFieldArgs.xfbAddr, s_beginFieldArgs.fbWidth, s_beginFieldArgs.fbHeight,rc);
			s_swapRequested.Clear();
		}
	}
}

void VideoBackendHardware::InitializeShared()
{
	VideoCommon_Init();

	s_swapRequested.Clear();
	s_efbAccessRequested.Clear();
	s_perfQueryRequested.Clear();
	s_FifoShuttingDown.Clear();
	memset((void*)&s_beginFieldArgs, 0, sizeof(s_beginFieldArgs));
	memset(&s_accessEFBArgs, 0, sizeof(s_accessEFBArgs));
	s_AccessEFBResult = 0;
	m_invalid = false;
}

void VideoBackendHardware::Video_ExitLoop()
{
	ExitGpuLoop();
	s_FifoShuttingDown.Set();
	s_efbAccessReadyEvent.Set();
	s_perfQueryReadyEvent.Set();
}

// Run from the CPU thread (from VideoInterface.cpp)
void VideoBackendHardware::Video_EndField()
{
	if (s_BackendInitialized)
	{
		s_swapRequested.Set();
	}
}

void Host_Message(int Id)
{
  if (Id == WM_USER_STOP)
  {
    s_running.Clear();
    updateMainFrameEvent.Set();
  }
}

 virtual void MainLoop()
 {
   while (s_running.IsSet())
   {
     Core::HostDispatchJobs();
     std::this_thread::sleep_for(std::chrono::milliseconds(100));
   }
 }

void VideoBackendHardware::InitializeShared()
{
	VideoCommon_Init();

	s_FifoShuttingDown.Clear();
	memset((void*)&s_beginFieldArgs, 0, sizeof(s_beginFieldArgs));
	m_invalid = false;
}

static void signal_handler(int)
{
  const char message[] = "A signal was received. A second signal will force Dolphin to stop.\n";
  if (write(STDERR_FILENO, message, sizeof(message)) < 0)
  {
  }
  s_shutdown_requested.Set();
}

void EmulatorState(bool running)
{
  s_emu_running_state.Set(running);
  if (running)
    s_gpu_mainloop.Wakeup();
  else
    s_gpu_mainloop.AllowSleep();
}

// May be executed from any thread, even the graphics thread.
// Created to allow for self shutdown.
void ExitGpuLoop()
{
  // This should break the wait loop in CPU thread
  CommandProcessor::fifo.bFF_GPReadEnable = false;
  FlushGpu();

  // Terminate GPU thread loop
  s_emu_running_state.Set();
  s_gpu_mainloop.Stop(false);
}

void HiresTexture::Shutdown()
{
  if (s_prefetcher.joinable())
  {
    s_textureCacheAbortLoading.Set();
    s_prefetcher.join();
  }

  s_textureMap.clear();
  s_textureCache.clear();
}

static void StopDVDThread()
{
  ASSERT(s_dvd_thread.joinable());

  // By setting s_DVD_thread_exiting, we ask the DVD thread to cleanly exit.
  // In case the request queue is empty, we need to set s_request_queue_expanded
  // so that the DVD thread will wake up and check s_DVD_thread_exiting.
  s_dvd_thread_exiting.Set();
  s_request_queue_expanded.Set();

  s_dvd_thread.join();
}

u32 VideoBackendHardware::Video_GetQueryResult(PerfQueryType type)
{
	if (!g_perf_query->ShouldEmulate())
	{
		return 0;
	}

	// TODO: Is this check sane?
	if (!g_perf_query->IsFlushed())
	{
		if (SConfig::GetInstance().m_LocalCoreStartupParameter.bCPUThread)
		{
			s_perfQueryReadyEvent.Reset();
			if (s_FifoShuttingDown.IsSet())
				return 0;
			s_perfQueryRequested.Set();
			s_perfQueryReadyEvent.Wait();
		}
		else
			g_perf_query->FlushResults();
	}

	return g_perf_query->GetQueryResult(type);
}

// Run from the graphics thread (from Fifo.cpp)
void VideoFifo_CheckSwapRequestAt(u32 xfbAddr, u32 fbWidth, u32 fbHeight)
{
	if (g_ActiveConfig.bUseXFB)
	{
		if (s_swapRequested.IsSet())
		{
			u32 aLower = xfbAddr;
			u32 aUpper = xfbAddr + 2 * fbWidth * fbHeight;
			u32 bLower = s_beginFieldArgs.xfbAddr;
			u32 bUpper = s_beginFieldArgs.xfbAddr + 2 * s_beginFieldArgs.fbWidth * s_beginFieldArgs.fbHeight;

			if (addrRangesOverlap(aLower, aUpper, bLower, bUpper))
				VideoFifo_CheckSwapRequest();
		}
	}
}

void HiresTexture::Prefetch()
{
	Common::SetCurrentThreadName("Prefetcher");

	u32 starttime = Common::Timer::GetTimeMs();
	for (const auto& entry : s_textureMap)
	{
		const std::string& base_filename = entry.first;

		std::unique_lock<std::mutex> lk(s_textureCacheMutex);

		auto iter = s_textureCache.find(base_filename);
		if (iter == s_textureCache.end())
		{
			lk.unlock();
			HiresTexture* ptr = Load(base_filename, [](size_t requested_size)
			{
				return new u8[requested_size];
			}, true);
			lk.lock();
			if (ptr != nullptr)
			{
				size_sum.fetch_add(ptr->m_cached_data_size);
				iter = s_textureCache.insert(iter, std::make_pair(base_filename, std::shared_ptr<HiresTexture>(ptr)));
			}
		}

		if (s_textureCacheAbortLoading.IsSet())
		{
			return;
		}

		if (size_sum.load() > max_mem)
		{
			g_Config.bCacheHiresTextures = false;

			OSD::AddMessage(StringFromFormat("Custom Textures prefetching after %.1f MB aborted, not enough RAM available", size_sum / (1024.0 * 1024.0)), 10000);
			return;
		}
	}
	u32 stoptime = Common::Timer::GetTimeMs();
	OSD::AddMessage(StringFromFormat("Custom Textures loaded, %.1f MB in %.1f s", size_sum / (1024.0 * 1024.0), (stoptime - starttime) / 1000.0), 10000);
}