Add reference counter of DxgiDuplicatorController to unload DXGI components

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h

Index: webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
diff --git a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
index c9838ad7a1e5d63c918da9b22fcde0c0276d0dac..0ad89e840edae9ba3cd6c57c6f88be1ccae9fa53 100644
--- a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
+++ b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
@@ -13,10 +13,11 @@
 
 #include <D3DCommon.h>
 
-#include <memory>
+#include <atomic>
 #include <vector>
 
 #include "webrtc/base/criticalsection.h"
+#include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/modules/desktop_capture/desktop_geometry.h"
 #include "webrtc/modules/desktop_capture/resolution_change_detector.h"
 #include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
@@ -39,8 +40,14 @@ namespace webrtc {
 // changing. Consumers should retry after a while. (Typically 50 milliseconds,
 // but according to hardware performance, this time may vary.)
 class DxgiDuplicatorController {
+ private:
+  struct ReferenceReleaser final {

[Sergey Ulanov, 2017/06/19 18:52:43]

I don't think you need this anymore

[Hzj_jie, 2017/06/19 20:19:46]

Done.

+    void operator()(DxgiDuplicatorController* instance) const;
+  };
+
  public:
   using Context = DxgiFrameContext;
+  using Reference = rtc::scoped_refptr<DxgiDuplicatorController>;

[Sergey Ulanov, 2017/06/19 18:52:43]

I'd prefer to use scoped_refptr<> directly. It won't be used in too many places,
so adding this shortcut doesn't make code more readable.

[Hzj_jie, 2017/06/19 20:19:47]

Done.

 
   // A collection of D3d information we are interested on, which may impact
   // capturer performance or reliability.
@@ -65,14 +72,11 @@ class DxgiDuplicatorController {
     INVALID_MONITOR_ID,
   };
 
+  // Deprecated: use "GetRefence()" instead.

[Sergey Ulanov, 2017/06/19 18:52:43]

Maybe just update this function to return scoped_refptr<>?
There is only a handful places where it's called, so all callers can be updated
in the same CL.

[Hzj_jie, 2017/06/19 20:19:46]

Done. The only concern is the name "Instance()" does not reflect that this
function returns a scoped_refptr instead of an instance.

[Do not use (sergeyu), 2017/06/19 20:54:44]

I think Instance() is still fine. We still have only once instance, but it's
ref-counted now.

   // Returns the singleton instance of DxgiDuplicatorController.
   static DxgiDuplicatorController* Instance();
 
-  // Destructs current instance. We need to make sure COM components and their
-  // containers are destructed in correct order. This function calls
-  // Deinitialize() to do the real work.
-  ~DxgiDuplicatorController();
-
+  static Reference GetReference();
   // All the following public functions implicitly call Initialize() function.
 
   // Detects whether the system supports DXGI based capturer.
@@ -107,16 +111,32 @@ class DxgiDuplicatorController {
   // destructing.
   friend DxgiFrameContext::~DxgiFrameContext();
 
+  // scoped_refptr<DxgiDuplicatorController> accesses private AddRef() and
+  // Release() functions.
+  friend class rtc::scoped_refptr<DxgiDuplicatorController>;
+
   // A private constructor to ensure consumers to use
-  // DxgiDuplicatorController::Instance().
+  // DxgiDuplicatorController::GetReference().
   DxgiDuplicatorController();
 
+  // Not implemented: The singleton DxgiDuplicatorController instance should not
+  // be deleted.
+  ~DxgiDuplicatorController();
+
+  // RefCountedInterface implementations.
+  void AddRef() const;
+  void Release();
+
   // Does the real duplication work. Setting |monitor_id| < 0 to capture entire
   // screen. This function calls Initialize(). And if the duplication failed,
   // this function calls Deinitialize() to ensure the Dxgi components can be
   // reinitialized next time.
   Result DoDuplicate(DxgiFrame* frame, int monitor_id);
 
+  // Unload all the DXGI components and releases the resources. This function
+  // wraps Deinitialize() with |lock_|.
+  void Unload();
+
   // Unregisters Context from this instance and all DxgiAdapterDuplicator(s)
   // it owns.
   void Unregister(const Context* const context);
@@ -185,6 +205,9 @@ class DxgiDuplicatorController {
   // DxgiAdapterDuplicator and DxgiOutputDuplicator instances are initialized.
   void TranslateRect();
 
+  // The count of references which are now "living".
+  static std::atomic_int refcount_;
+
   // This lock must be locked whenever accessing any of the following objects.
   rtc::CriticalSection lock_;