DirectX capturer may crash after switching shared screen

webrtc/modules/desktop_capture/win/dxgi_output_duplicator.h

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 18 matching lines @@
 #include "webrtc/modules/desktop_capture/win/dxgi_texture.h"
 
 namespace webrtc {
 
 // Duplicates the content on one IDXGIOutput, i.e. one monitor attached to one
 // video card. None of functions in this class is thread-safe.
 class DxgiOutputDuplicator {
  public:
   struct Context {
     // The updated region DxgiOutputDuplicator::DetectUpdatedRegion() output
-    // during last Duplicate() function call. It's a DesktopRegion translated by
-    // offset of each DxgiOutputDuplicator instance.
+    // during last Duplicate() function call. It's always relative to the
+    // (0, 0).
     DesktopRegion updated_region;
   };
 
   // Creates an instance of DxgiOutputDuplicator from a D3dDevice and one of its
   // IDXGIOutput1. Caller must maintain the lifetime of device, to make sure it
   // outlives this instance. Only DxgiAdapterDuplicator can create an instance.
   DxgiOutputDuplicator(const D3dDevice& device,
                        const Microsoft::WRL::ComPtr<IDXGIOutput1>& output,
                        const DXGI_OUTPUT_DESC& desc);
 
@@ skipping 22 matching lines @@
   DesktopRect desktop_rect() const { return desktop_rect_; }
 
   void Setup(Context* context);
 
   void Unregister(const Context* const context);
 
   // How many frames have been captured by this DxigOutputDuplicator.
   int64_t num_frames_captured() const;
 
  private:
-  // Detects updated region translated by offset from IDXGIOutput1. This
-  // function will set the |updated_region| as entire DesktopRect starts from
-  // offset if it failed to execute Windows APIs.
+  // Calls DoDetectUpdatedRegion(). If it fails, this function sets the
+  // |updated_region| as entire UntranslatedDesktopRect().
   void DetectUpdatedRegion(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
-                           DesktopVector offset,
                            DesktopRegion* updated_region);
 
   // Returns untranslated updated region, which are directly returned by Windows
   // APIs. Returns false in case of a failure.
   bool DoDetectUpdatedRegion(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
                              DesktopRegion* updated_region);
 
   bool ReleaseFrame();
 
   // Initializes duplication_ instance. Expects duplication_ is in empty status.
   // Returns false if system does not support IDXGIOutputDuplication.
   bool DuplicateOutput();
 
-  // Returns a DesktopRect with the same size of desktop_size_, but translated
+  // Returns a DesktopRect with the same size of desktop_size(), but translated
   // by offset.
-  DesktopRect TranslatedDesktopRect(DesktopVector offset);
+  DesktopRect TranslatedDesktopRect(DesktopVector offset) const;
+
+  // Returns a DesktopRect with the same size of desktop_size(), but starts from
+  // (0, 0).
+  DesktopRect UntranslatedDesktopRect() const;
 
   // Spreads changes from |context| to other registered Context(s) in
   // contexts_.
   void SpreadContextChange(const Context* const context);
 
+  // Returns the size of desktop rectangle current instance representing.
+  DesktopSize desktop_size() const;
+
   const D3dDevice device_;
   const Microsoft::WRL::ComPtr<IDXGIOutput1> output_;
   const DesktopRect desktop_rect_;
   Microsoft::WRL::ComPtr<IDXGIOutputDuplication> duplication_;
   DXGI_OUTDUPL_DESC desc_;
   std::vector<uint8_t> metadata_;
   std::unique_ptr<DxgiTexture> texture_;
   Rotation rotation_;
   DesktopSize unrotated_size_;
 
   // After each AcquireNextFrame() function call, updated_region_(s) of all
   // active Context(s) need to be updated. Since they have missed the
   // change this time. And during next Duplicate() function call, their
   // updated_region_ will be merged and copied.
   std::vector<Context*> contexts_;
 
   // The last full frame of this output and its offset. If on AcquireNextFrame()
   // failed because of timeout, i.e. no update, we can copy content from
   // |last_frame_|.
   std::unique_ptr<SharedDesktopFrame> last_frame_;
   DesktopVector last_frame_offset_;
 
   int64_t num_frames_captured_ = 0;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_OUTPUT_DUPLICATOR_H_