[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
index 159e5a9195b516da17157a4e491b82b10afdff19..b0397e35116e8537ccd242d3b545479297be50b7 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
@@ -10,458 +10,24 @@
 
 #include "webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h"
 
-#include <string.h>
-
-#include <comdef.h>
-#include <wincodec.h>
-#include <wingdi.h>
-#include <DXGI.h>
-
-#include "webrtc/base/checks.h"
-#include "webrtc/base/criticalsection.h"
-#include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/base/logging.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
-#include "webrtc/modules/desktop_capture/win/screen_capture_utils.h"
-#include "webrtc/system_wrappers/include/atomic32.h"
-#include "webrtc/system_wrappers/include/logging.h"
+#include "webrtc/modules/desktop_capture/win/dxgi_duplicator_container.h"
 
 namespace webrtc {
 
 using Microsoft::WRL::ComPtr;
 
-namespace {
-
-// Timeout for AcquireNextFrame() call.
-const int kAcquireTimeoutMs = 10;
-
-// Wait time between two DuplicateOutput operations, DuplicateOutput may fail if
-// display mode is changing.
-const int kDuplicateOutputWaitMs = 50;
-
-// How many times we attempt to DuplicateOutput before returning an error to
-// upstream components.
-const int kDuplicateOutputAttempts = 10;
-
-rtc::GlobalLockPod g_initialize_lock;
-
-// A container of all the objects we need to call Windows API. Note, one
-// application can only have one IDXGIOutputDuplication instance, that's the
-// reason the container is singleton.
-struct DxgiContainer {
-  rtc::CriticalSection duplication_lock;
-  rtc::CriticalSection acquire_lock;
-  bool initialize_result GUARDED_BY(g_initialize_lock) = false;
-  ID3D11Device* device GUARDED_BY(g_initialize_lock) = nullptr;
-  ID3D11DeviceContext* context GUARDED_BY(g_initialize_lock) = nullptr;
-  IDXGIOutput1* output1 GUARDED_BY(g_initialize_lock) = nullptr;
-  ComPtr<IDXGIOutputDuplication> duplication
-      GUARDED_BY(duplication_lock);
-  DXGI_OUTDUPL_DESC duplication_desc;
-  std::vector<uint8_t> metadata GUARDED_BY(acquire_lock);
-};
-
-DxgiContainer* g_container GUARDED_BY(g_initialize_lock);
-
-}  // namespace
-
-// A pair of an ID3D11Texture2D and an IDXGISurface. We need an
-// ID3D11Texture2D instance to copy GPU texture to RAM, but an IDXGISurface to
-// map the texture into a bitmap buffer. These two instances are always
-// pointing to a same object.
-// This class also has two DesktopRegions, one is the updated region from
-// returned from Windows API, the other is the region intersects with the
-// updated region of last frame.
-//
-// This class is not thread safe.
-class ScreenCapturerWinDirectx::Texture {
- public:
-  // Copy a frame represented by frame_info and resource. Returns false if
-  // anything wrong.
-  bool CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
-                IDXGIResource* resource,
-                const DesktopRegion& last_updated_region) {
-    if (!resource || frame_info.AccumulatedFrames == 0) {
-      // Nothing updated, but current data is still valid.
-      return false;
-    }
-
-    ComPtr<ID3D11Texture2D> texture;
-    _com_error error = resource->QueryInterface(
-        __uuidof(ID3D11Texture2D),
-        reinterpret_cast<void**>(texture.GetAddressOf()));
-    if (error.Error() != S_OK || !texture) {
-      LOG(LS_ERROR) << "Failed to convert IDXGIResource to ID3D11Texture2D, "
-                       "error "
-                    << error.ErrorMessage() << ", code " << error.Error();
-      return false;
-    }
-
-    // AcquireNextFrame returns a CPU inaccessible IDXGIResource, so we need to
-    // make a copy.
-    if (!InitializeStage(texture.Get())) {
-      return false;
-    }
-
-    updated_region_.Clear();
-    if (!DetectUpdatedRegion(frame_info, &updated_region_)) {
-      updated_region_.SetRect(DesktopRect::MakeSize(size()));
-    }
-    // We need to copy changed area in both this frame and last frame, since
-    // currently this frame stores the bitmap of the one before last frame.
-    copied_region_.Clear();
-    copied_region_.AddRegion(updated_region_);
-    copied_region_.AddRegion(last_updated_region);
-    copied_region_.IntersectWith(DesktopRect::MakeSize(size()));
-
-    for (DesktopRegion::Iterator it(copied_region_);
-         !it.IsAtEnd();
-         it.Advance()) {
-      D3D11_BOX box;
-      box.left = it.rect().left();
-      box.top = it.rect().top();
-      box.right = it.rect().right();
-      box.bottom = it.rect().bottom();
-      box.front = 0;
-      box.back = 1;
-      g_container->context->CopySubresourceRegion(
-          static_cast<ID3D11Resource*>(stage_.Get()),
-          0, it.rect().left(), it.rect().top(), 0,
-          static_cast<ID3D11Resource*>(texture.Get()),
-          0, &box);
-    }
-
-    rect_ = {0};
-    error = _com_error(surface_->Map(&rect_, DXGI_MAP_READ));
-    if (error.Error() != S_OK) {
-      rect_ = {0};
-      LOG(LS_ERROR) << "Failed to map the IDXGISurface to a bitmap, error "
-                    << error.ErrorMessage() << ", code " << error.Error();
-      return false;
-    }
-
-    // surface_->Unmap() will be called next time we capture an image to avoid
-    // memory copy without shared_memory.
-    return true;
-  }
-
-  uint8_t* bits() const { return static_cast<uint8_t*>(rect_.pBits); }
-  int pitch() const { return static_cast<int>(rect_.Pitch); }
-  const DesktopSize& size() const { return size_; }
-  const DesktopVector& dpi() const { return dpi_; }
-
-  int32_t AddRef() {
-    return ++ref_count_;
-  }
-
-  int32_t Release() {
-    int32_t ref_count;
-    ref_count = --ref_count_;
-    if (ref_count == 0) {
-      delete this;
-    }
-    return ref_count;
-  }
-
-  const DesktopRegion& updated_region() {
-    return updated_region_;
-  }
-
-  const DesktopRegion& copied_region() {
-    return copied_region_;
-  }
-
- private:
-  // Texture should only be deleted by Release function.
-  ~Texture() = default;
-
-  // Initializes stage_ from a CPU inaccessible IDXGIResource. Returns false
-  // if it fails to execute windows api.
-  bool InitializeStage(ID3D11Texture2D* texture) {
-    RTC_DCHECK(texture);
-    D3D11_TEXTURE2D_DESC desc = {0};
-    texture->GetDesc(&desc);
-    desc.BindFlags = 0;
-    desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
-    desc.MiscFlags = 0;
-    desc.Usage = D3D11_USAGE_STAGING;
-    if (stage_) {
-      // Make sure stage_ and surface_ are always pointing to a same object.
-      // We need an ID3D11Texture2D instance for
-      // ID3D11DeviceContext::CopySubresourceRegion, but an IDXGISurface for
-      // IDXGISurface::Map.
-      {
-        ComPtr<IUnknown> left;
-        ComPtr<IUnknown> right;
-        bool left_result = SUCCEEDED(stage_.As(&left));
-        bool right_result = SUCCEEDED(surface_.As(&right));
-        RTC_DCHECK(left_result);
-        RTC_DCHECK(right_result);
-        RTC_DCHECK(left.Get() == right.Get());
-      }
-
-      // This buffer should be used already.
-      _com_error error = _com_error(surface_->Unmap());
-      if (error.Error() == S_OK) {
-        D3D11_TEXTURE2D_DESC current_desc;
-        stage_->GetDesc(&current_desc);
-        if (memcmp(&desc, &current_desc, sizeof(D3D11_TEXTURE2D_DESC)) == 0) {
-          return true;
-        }
-      } else {
-        // Let's recreate stage_ and surface_ later.
-        LOG(LS_ERROR) << "Failed to unmap surface, error "
-                      << error.ErrorMessage() << ", code " << error.Error();
-      }
-
-      stage_.Reset();
-      surface_.Reset();
-    } else {
-      RTC_DCHECK(!surface_);
-    }
-
-    HDC hdc = GetDC(nullptr);
-    // Use old DPI value if failed.
-    if (hdc != nullptr) {
-      dpi_.set(GetDeviceCaps(hdc, LOGPIXELSX), GetDeviceCaps(hdc, LOGPIXELSY));
-      ReleaseDC(nullptr, hdc);
-    }
-
-    _com_error error = _com_error(g_container->device->CreateTexture2D(
-        &desc, nullptr, stage_.GetAddressOf()));
-    if (error.Error() != S_OK || !stage_) {
-      LOG(LS_ERROR) << "Failed to create a new ID3D11Texture2D as stage, "
-                       "error "
-                    << error.ErrorMessage() << ", code " << error.Error();
-      return false;
-    }
-
-    error = _com_error(stage_.As(&surface_));
-    if (error.Error() != S_OK || !surface_) {
-      LOG(LS_ERROR) << "Failed to convert ID3D11Texture2D to IDXGISurface, "
-                       "error "
-                    << error.ErrorMessage() << ", code " << error.Error();
-      return false;
-    }
-
-    size_.set(desc.Width, desc.Height);
-    return true;
-  }
-
-  ComPtr<ID3D11Texture2D> stage_;
-  ComPtr<IDXGISurface> surface_;
-  DXGI_MAPPED_RECT rect_;
-  DesktopSize size_;
-  Atomic32 ref_count_;
-  // The updated region from Windows API.
-  DesktopRegion updated_region_;
-  // Combination of updated regions from both current frame and previous frame.
-  DesktopRegion copied_region_;
-  // The DPI of current frame.
-  DesktopVector dpi_;
-};
-
-// A DesktopFrame which does not own the data buffer, and also does not have
-// shared memory. This uses in IT2ME scenario only.
-class ScreenCapturerWinDirectx::DxgiDesktopFrame : public DesktopFrame {
- public:
-  DxgiDesktopFrame(
-      const rtc::scoped_refptr<ScreenCapturerWinDirectx::Texture>& texture)
-      : DesktopFrame(texture.get()->size(),
-                     texture.get()->pitch(),
-                     texture.get()->bits(),
-                     nullptr),
-        texture_(texture) {
-    set_dpi(texture->dpi());
-  }
-
-  virtual ~DxgiDesktopFrame() {}
-
- private:
-  // Keep a reference to the Texture instance to make sure we can still access
-  // its bytes array.
-  rtc::scoped_refptr<ScreenCapturerWinDirectx::Texture> texture_;
-};
-
 bool ScreenCapturerWinDirectx::Initialize() {
-  if (!g_container) {
-    rtc::GlobalLockScope lock(&g_initialize_lock);
-    if (!g_container) {
-      g_container = new DxgiContainer();
-      g_container->initialize_result = DoInitialize();
-      if (g_container->initialize_result) {
-        return true;
-      }
-
-      // Clean up if DirectX cannot work on the system.
-      if (g_container->duplication) {
-        g_container->duplication.Reset();
-      }
-
-      if (g_container->output1) {
-        g_container->output1->Release();
-        g_container->output1 = nullptr;
-      }
-
-      if (g_container->context) {
-        g_container->context->Release();
-        g_container->context = nullptr;
-      }
-
-      if (g_container->device) {
-        g_container->device->Release();
-        g_container->device = nullptr;
-      }
-
-      return false;
-    }
-  }
-
-  return g_container->initialize_result;
-}
-
-bool ScreenCapturerWinDirectx::DoInitialize() {
-  D3D_FEATURE_LEVEL feature_level;
-  _com_error error = D3D11CreateDevice(
-      nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr,
-      D3D11_CREATE_DEVICE_BGRA_SUPPORT | D3D11_CREATE_DEVICE_SINGLETHREADED,
-      nullptr, 0, D3D11_SDK_VERSION, &g_container->device, &feature_level,
-      &g_container->context);
-  if (error.Error() != S_OK || !g_container->device || !g_container->context) {
-    LOG(LS_WARNING) << "D3D11CreateDeivce returns error "
-                    << error.ErrorMessage() << " with code " << error.Error();
-    return false;
-  }
-
-  if (feature_level < D3D_FEATURE_LEVEL_11_0) {
-    LOG(LS_WARNING) << "D3D11CreateDevice returns an instance without DirectX "
-                       "11 support, level "
-                    << feature_level;
-    return false;
-  }
-
-  ComPtr<IDXGIDevice> device;
-  error = _com_error(g_container->device->QueryInterface(
-      __uuidof(IDXGIDevice), reinterpret_cast<void**>(device.GetAddressOf())));
-  if (error.Error() != S_OK || !device) {
-    LOG(LS_WARNING) << "ID3D11Device is not an implementation of IDXGIDevice, "
-                       "this usually means the system does not support DirectX "
-                       "11";
-    return false;
-  }
-
-  ComPtr<IDXGIAdapter> adapter;
-  error = _com_error(device->GetAdapter(adapter.GetAddressOf()));
-  if (error.Error() != S_OK || !adapter) {
-    LOG(LS_WARNING) << "Failed to get an IDXGIAdapter implementation from "
-                       "IDXGIDevice.";
-    return false;
-  }
-
-  ComPtr<IDXGIOutput> output;
-  for (int i = 0;; i++) {
-    error = _com_error(adapter->EnumOutputs(i, output.GetAddressOf()));
-    if (error.Error() == DXGI_ERROR_NOT_FOUND) {
-      LOG(LS_WARNING) << "No output detected.";
-      return false;
-    }
-    if (error.Error() == S_OK && output) {
-      DXGI_OUTPUT_DESC desc;
-      error = _com_error(output->GetDesc(&desc));
-      if (error.Error() == S_OK) {
-        if (desc.AttachedToDesktop) {
-          // Current output instance is the device attached to desktop.
-          break;
-        }
-      } else {
-        LOG(LS_WARNING) << "Failed to get output description of device " << i
-                        << ", ignore.";
-      }
-    }
-  }
-
-  RTC_DCHECK(output);
-  error = _com_error(output.CopyTo(
-      __uuidof(IDXGIOutput1), reinterpret_cast<void**>(&g_container->output1)));
-  if (error.Error() != S_OK || !g_container->output1) {
-    LOG(LS_WARNING) << "Failed to convert IDXGIOutput to IDXGIOutput1, this "
-                       "usually means the system does not support DirectX 11";
-    return false;
-  }
-
-  // When we are initializing the DXGI, retrying several times to avoid any
-  // temporary issue, such as display mode changing, to block us from using
-  // DXGI based capturer.
-  for (int i = 0; i < kDuplicateOutputAttempts; i++) {
-    if (DuplicateOutput()) {
-      return true;
-    }
-    Sleep(kDuplicateOutputWaitMs);
-  }
-  return false;
-}
-
-bool ScreenCapturerWinDirectx::DuplicateOutput() {
-  // We are updating the instance.
-  rtc::CritScope lock(&g_container->duplication_lock);
-  // Make sure nobody is using current instance.
-  rtc::CritScope lock2(&g_container->acquire_lock);
-  if (g_container->duplication) {
-    return true;
-  }
-
-  _com_error error = g_container->output1->DuplicateOutput(
-      static_cast<IUnknown*>(g_container->device),
-      g_container->duplication.GetAddressOf());
-  if (error.Error() != S_OK || !g_container->duplication) {
-    g_container->duplication.Reset();
-    LOG(LS_WARNING) << "Failed to duplicate output from IDXGIOutput1, error "
-                    << error.ErrorMessage() << ", with code "
-                    << error.Error();
-    return false;
-  }
-
-  memset(&g_container->duplication_desc, 0, sizeof(DXGI_OUTDUPL_DESC));
-  g_container->duplication->GetDesc(&g_container->duplication_desc);
-  if (g_container->duplication_desc.ModeDesc.Format !=
-      DXGI_FORMAT_B8G8R8A8_UNORM) {
-    g_container->duplication.Reset();
-    LOG(LS_ERROR) << "IDXGIDuplicateOutput does not use RGBA (8 bit) "
-                     "format, which is required by downstream components, "
-                     "format is "
-                  << g_container->duplication_desc.ModeDesc.Format;
-    return false;
-  }
-
-  return true;
-}
-
-bool ScreenCapturerWinDirectx::ForceDuplicateOutput() {
-  // We are updating the instance.
-  rtc::CritScope lock(&g_container->duplication_lock);
-  // Make sure nobody is using current instance.
-  rtc::CritScope lock2(&g_container->acquire_lock);
-
-  if (g_container->duplication) {
-    g_container->duplication->ReleaseFrame();
-    g_container->duplication.Reset();
-  }
-
-  return DuplicateOutput();
+  // Initializes DxgiDuplicatorContainer for the first time to decide whether
+  // the system supports DirectX based capturer.
+  return DxgiDuplicatorContainer::Instance()->Prepare();
 }
 
 ScreenCapturerWinDirectx::ScreenCapturerWinDirectx(
     const DesktopCaptureOptions& options)
-    : callback_(nullptr) {
-  RTC_DCHECK(g_container && g_container->initialize_result);
-
-  // Texture instance won't change forever.
-  while (!surfaces_.current_frame()) {
-    surfaces_.ReplaceCurrentFrame(std::unique_ptr<rtc::scoped_refptr<Texture>>(
-        new rtc::scoped_refptr<Texture>(new Texture())));
-    surfaces_.MoveToNextFrame();
-  }
-}
+    : callback_(nullptr) {}
 
 ScreenCapturerWinDirectx::~ScreenCapturerWinDirectx() {}
 
@@ -477,202 +43,68 @@ void ScreenCapturerWinDirectx::SetSharedMemoryFactory(
   shared_memory_factory_ = std::move(shared_memory_factory);
 }
 
-bool ScreenCapturerWinDirectx::HandleDetectUpdatedRegionError(
-    const _com_error& error,
-    const char* stage) {
-  if (error.Error() != S_OK) {
-    if (error.Error() == DXGI_ERROR_ACCESS_LOST) {
-      ForceDuplicateOutput();
-    } else {
-      LOG(LS_ERROR) << "Failed to get " << stage << " rectangles, error "
-                    << error.ErrorMessage() << ", code " << error.Error();
-    }
-    // Send entire desktop as we cannot get dirty or move rectangles.
-    return false;
+DesktopSize ScreenCapturerWinDirectx::SelectedDesktopSize() const {
+  if (current_screen_id == kFullDesktopScreenId) {
+    return DxgiDuplicatorContainer::Instance()->desktop_size();
   }
-
-  return true;
-}
-
-bool ScreenCapturerWinDirectx::DetectUpdatedRegion(
-    const DXGI_OUTDUPL_FRAME_INFO& frame_info,
-    DesktopRegion* updated_region) {
-  RTC_DCHECK(g_container->duplication);
-  RTC_DCHECK(updated_region);
-  updated_region->Clear();
-  if (frame_info.TotalMetadataBufferSize == 0) {
-    // This should not happen, since frame_info.AccumulatedFrames > 0.
-    LOG(LS_ERROR) << "frame_info.AccumulatedFrames > 0, "
-                     "but TotalMetadataBufferSize == 0";
-    return false;
-  }
-
-  if (g_container->metadata.capacity() < frame_info.TotalMetadataBufferSize) {
-    g_container->metadata.clear();  // Avoid data copy
-    g_container->metadata.reserve(frame_info.TotalMetadataBufferSize);
-  }
-
-  UINT buff_size = 0;
-  DXGI_OUTDUPL_MOVE_RECT* move_rects =
-      reinterpret_cast<DXGI_OUTDUPL_MOVE_RECT*>(g_container->metadata.data());
-  size_t move_rects_count = 0;
-  _com_error error = _com_error(g_container->duplication->GetFrameMoveRects(
-      static_cast<UINT>(g_container->metadata.capacity()),
-      move_rects, &buff_size));
-  if (!HandleDetectUpdatedRegionError(error, "move")) {
-    return false;
-  }
-  move_rects_count = buff_size / sizeof(DXGI_OUTDUPL_MOVE_RECT);
-
-  RECT* dirty_rects =
-      reinterpret_cast<RECT*>(g_container->metadata.data() + buff_size);
-  size_t dirty_rects_count = 0;
-  error = _com_error(g_container->duplication->GetFrameDirtyRects(
-      static_cast<UINT>(g_container->metadata.capacity()) - buff_size,
-      dirty_rects, &buff_size));
-  if (!HandleDetectUpdatedRegionError(error, "dirty")) {
-    return false;
-  }
-  dirty_rects_count = buff_size / sizeof(RECT);
-
-  while (move_rects_count > 0) {
-    updated_region->AddRect(DesktopRect::MakeXYWH(
-        move_rects->SourcePoint.x, move_rects->SourcePoint.y,
-        move_rects->DestinationRect.right - move_rects->DestinationRect.left,
-        move_rects->DestinationRect.bottom - move_rects->DestinationRect.top));
-    updated_region->AddRect(DesktopRect::MakeLTRB(
-        move_rects->DestinationRect.left, move_rects->DestinationRect.top,
-        move_rects->DestinationRect.right, move_rects->DestinationRect.bottom));
-    move_rects++;
-    move_rects_count--;
-  }
-
-  while (dirty_rects_count > 0) {
-    updated_region->AddRect(DesktopRect::MakeLTRB(
-        dirty_rects->left, dirty_rects->top,
-        dirty_rects->right, dirty_rects->bottom));
-    dirty_rects++;
-    dirty_rects_count--;
-  }
-
-  return true;
-}
-
-std::unique_ptr<DesktopFrame> ScreenCapturerWinDirectx::ProcessFrame(
-    const DXGI_OUTDUPL_FRAME_INFO& frame_info,
-    IDXGIResource* resource) {
-  RTC_DCHECK(resource);
-  RTC_DCHECK(frame_info.AccumulatedFrames > 0);
-  // We have something to update, so move to next surface.
-  surfaces_.MoveToNextFrame();
-  if (shared_memory_factory_) {
-    // Make sure frames_ and surfaces_ are synchronized if we are using both.
-    frames_.MoveToNextFrame();
-  }
-  RTC_DCHECK(surfaces_.current_frame());
-  if (!surfaces_.current_frame()->get()->CopyFrom(frame_info, resource,
-          surfaces_.previous_frame()->get()->updated_region())) {
-    return std::unique_ptr<DesktopFrame>();
-  }
-
-  std::unique_ptr<DesktopFrame> result;
-  if (shared_memory_factory_) {
-    // When using shared memory, |frames_| is used to store a queue of
-    // SharedMemoryDesktopFrame's.
-    if (!frames_.current_frame() ||
-        !frames_.current_frame()->size().equals(
-            surfaces_.current_frame()->get()->size())) {
-      // Current frame does not have a same size as last captured surface.
-      std::unique_ptr<DesktopFrame> new_frame =
-          SharedMemoryDesktopFrame::Create(
-              surfaces_.current_frame()->get()->size(),
-              shared_memory_factory_.get());
-      if (!new_frame) {
-        LOG(LS_ERROR) << "Failed to allocate a new SharedMemoryDesktopFrame";
-        return std::unique_ptr<DesktopFrame>();
-      }
-      frames_.ReplaceCurrentFrame(
-          SharedDesktopFrame::Wrap(std::move(new_frame)));
-    }
-    result = frames_.current_frame()->Share();
-
-    std::unique_ptr<DesktopFrame> frame(
-        new DxgiDesktopFrame(*surfaces_.current_frame()));
-    // Copy data into SharedMemory.
-    for (DesktopRegion::Iterator it(
-             surfaces_.current_frame()->get()->copied_region());
-         !it.IsAtEnd();
-         it.Advance()) {
-      result->CopyPixelsFrom(*frame, it.rect().top_left(), it.rect());
-    }
-    result->set_dpi(frame->dpi());
-  } else {
-    result.reset(new DxgiDesktopFrame(*surfaces_.current_frame()));
-  }
-  RTC_DCHECK(result);
-  *result->mutable_updated_region() =
-      surfaces_.current_frame()->get()->updated_region();
-  return result;
+  return DxgiDuplicatorContainer::Instance()
+      ->ScreenRect(current_screen_id).size();
 }
 
 void ScreenCapturerWinDirectx::Capture(const DesktopRegion& region) {
   RTC_DCHECK(callback_);
 
-  if (!g_container->duplication && !DuplicateOutput()) {
-    // Failed to initialize desktop duplication. This usually happens when
-    // Windows is switching display mode. Retrying later usually resolves the
-    // issue.
-    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
-    return;
-  }
-
-  RTC_DCHECK(g_container->duplication);
   int64_t capture_start_time_nanos = rtc::TimeNanos();
 
-  DXGI_OUTDUPL_FRAME_INFO frame_info;
-  memset(&frame_info, 0, sizeof(DXGI_OUTDUPL_FRAME_INFO));
-  ComPtr<IDXGIResource> resource;
-  rtc::CritScope lock(&g_container->acquire_lock);
-  _com_error error = g_container->duplication->AcquireNextFrame(
-      kAcquireTimeoutMs, &frame_info, resource.GetAddressOf());
-
-  if (error.Error() == DXGI_ERROR_WAIT_TIMEOUT) {
-    // Nothing changed.
-    EmitCurrentFrame();
+  if (!DxgiDuplicatorContainer::Instance()->Prepare(&context_)) {
+    // Since we have successfully initialized DirectX based capturer before,
+    // this should be a temporary issue. Maybe display mode is changing.
+    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
     return;
   }
 
-  if (error.Error() != S_OK) {
-    LOG(LS_ERROR) << "Failed to capture frame, error " << error.ErrorMessage()
-                  << ", code " << error.Error();
-    if (ForceDuplicateOutput()) {
-      EmitCurrentFrame();
+  frames_.MoveToNextFrame();
+  if (!frames_.current_frame()) {
+    std::unique_ptr<DesktopFrame> new_frame;
+    if (shared_memory_factory_) {
+      new_frame = SharedMemoryDesktopFrame::Create(
+          SelectedDesktopSize(), shared_memory_factory_.get());
     } else {
-      callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
+      new_frame.reset(new BasicDesktopFrame(SelectedDesktopSize()));
     }
-    return;
-  }
-
-  if (frame_info.AccumulatedFrames == 0) {
-    g_container->duplication->ReleaseFrame();
-    EmitCurrentFrame();
-    return;
+    if (!new_frame) {
+      LOG(LS_ERROR) << "Failed to allocate a new DesktopFrame.";
+      // This usually means we do not have enough memory or SharedMemoryFactory
+      // cannot work correctly.
+      callback_->OnCaptureResult(Result::ERROR_PERMANENT, nullptr);
+      return;
+    }
+    frames_.ReplaceCurrentFrame(
+        SharedDesktopFrame::Wrap(std::move(new_frame)));
   }
 
-  // Everything looks good so far, build next frame.
-  std::unique_ptr<DesktopFrame> result =
-      ProcessFrame(frame_info, resource.Get());
-  // DetectUpdatedRegion may release last g_container->duplication. But
-  // ForctDuplicateOutput function will always release last frame, so there is
-  // no potential leak.
-  if (g_container->duplication) {
-    g_container->duplication->ReleaseFrame();
-  }
-  if (!result) {
-    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
-    return;
+  if (current_screen_id == kFullDesktopScreenId) {
+    if (!DxgiDuplicatorContainer::Instance()->Duplicate(
+          &context_, frames_.current_frame(), frames_.previous_frame())) {
+      // Screen size may be changed, so we need to reset the frames.
+      frames_.Reset();
+      callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
+      return;
+    }
+  } else {
+    if (!DxgiDuplicatorContainer::Instance()->Duplicate(
+          &context_,
+          current_screen_id,

[Sergey Ulanov, 2016/07/26 00:48:52]

This argument can fit on the previous line.
git cl format please.

[Hzj_jie, 2016/07/26 02:13:02]

Done.

+          frames_.current_frame(),
+          frames_.previous_frame())) {
+      // Screen size may be changed, so we need to reset the frames.
+      frames_.Reset();
+      callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
+      return;
+    }
   }
 
+  std::unique_ptr<DesktopFrame> result = frames_.current_frame()->Share();
   result->set_capture_time_ms(
       (rtc::TimeNanos() - capture_start_time_nanos) /
       rtc::kNumNanosecsPerMillisec);
@@ -680,41 +112,35 @@ void ScreenCapturerWinDirectx::Capture(const DesktopRegion& region) {
 }
 
 bool ScreenCapturerWinDirectx::GetScreenList(ScreenList* screens) {
+  if (!DxgiDuplicatorContainer::Instance()->Prepare()) {
+    return false;
+  }
+
+  int screen_count = DxgiDuplicatorContainer::Instance()->ScreenCount();
+  for (int i = 0; i < screen_count; i++) {
+    screens->push_back(Screen{i});
+  }
   return true;
 }
 
 bool ScreenCapturerWinDirectx::SelectScreen(ScreenId id) {
-  // Only full desktop capture is supported.
-  return id == kFullDesktopScreenId;
-}
-
-void ScreenCapturerWinDirectx::EmitCurrentFrame() {
-  if (!surfaces_.current_frame()->get()->bits()) {
-    // At the very begining, we have not captured any frames.
-    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
-    return;
+  if (id == current_screen_id) {
+    return true;
   }
-
-  if (shared_memory_factory_) {
-    // If shared_memory_factory_ is provided, last frame is stored in frames_
-    // queue. If there is not an existing frame (at the very begining), we can
-    // only return a nullptr.
-    if (frames_.current_frame()) {
-      std::unique_ptr<SharedDesktopFrame> frame =
-          frames_.current_frame()->Share();
-      frame->mutable_updated_region()->Clear();
-      callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
-    } else {
-      callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
-    }
-    return;
+  if (!DxgiDuplicatorContainer::Instance()->Prepare()) {
+    return false;
   }
 
-  // If there is no shared_memory_factory_, last frame is stored in surfaces_
-  // queue.
-  std::unique_ptr<DesktopFrame> frame(
-      new DxgiDesktopFrame(*surfaces_.current_frame()));
-  callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
+  int screen_count = DxgiDuplicatorContainer::Instance()->ScreenCount();
+  if ((id >= 0 && id < screen_count) || id == kFullDesktopScreenId) {
+    current_screen_id = id;
+    // Target screen has been changed, existing DesktopFrame may not have
+    // consistent size with the new screen. So we need to clear the frames_.
+    // They will be initialized during next time Capture call.
+    frames_.Reset();
+    return true;
+  }
+  return false;
 }
 
 }  // namespace webrtc