Ensure Dxgi duplicator works correctly in session 0

webrtc/modules/desktop_capture/win/dxgi_adapter_duplicator.cc

 /*
  *  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 34 matching lines @@
 
 bool DxgiAdapterDuplicator::DoInitialize() {
   for (int i = 0;; i++) {
     ComPtr<IDXGIOutput> output;
     _com_error error =
         device_.dxgi_adapter()->EnumOutputs(i, output.GetAddressOf());
     if (error.Error() == DXGI_ERROR_NOT_FOUND) {
       break;
     }
 
+    if (error.Error() == DXGI_ERROR_NOT_CURRENTLY_AVAILABLE) {
+      LOG(LS_WARNING) << "IDXGIAdapter::EnumOutputs returns "
+                         "NOT_CURRENTLY_AVAILABLE. Is it running on session 0?";

[Sergey Ulanov, 2017/06/26 23:41:41]

Rephrase the second sentence as a statement instead of a question. E.g. "This
may happen when running in session 0."

[Hzj_jie, 2017/06/27 04:37:33]

Done.

+      break;
+    }
+
     if (error.Error() != S_OK || !output) {
       LOG(LS_WARNING) << "IDXGIAdapter::EnumOutputs returns an unexpected "
                          "result "
                       << error.ErrorMessage() << " with error code"
                       << error.Error();
-      return false;
+      continue;
     }
 
     DXGI_OUTPUT_DESC desc;
     error = output->GetDesc(&desc);
     if (error.Error() == S_OK) {
       if (desc.AttachedToDesktop && IsValidRect(desc.DesktopCoordinates)) {
         ComPtr<IDXGIOutput1> output1;
         error = output.As(&output1);
         if (error.Error() != S_OK || !output1) {
           LOG(LS_WARNING) << "Failed to convert IDXGIOutput to IDXGIOutput1, "
                              "this usually means the system does not support "
                              "DirectX 11";
-          return false;
+          continue;
         }
-        duplicators_.emplace_back(device_, output1, desc);
-        if (!duplicators_.back().Initialize()) {
-          return false;
+        DxgiOutputDuplicator duplicator(device_, output1, desc);
+        if (!duplicator.Initialize()) {
+          LOG(LS_WARNING) << "Failed to initialize DxgiOutputDuplicator on "
+                             "output "
+                          << i;
+          continue;
         }
+
+        duplicators_.push_back(std::move(duplicator));
         desktop_rect_.UnionWith(duplicators_.back().desktop_rect());
       }
     } else {
       LOG(LS_WARNING) << "Failed to get output description of device " << i
                       << ", ignore.";
     }
   }
-  return true;
+
+  if (duplicators_.empty()) {
+    LOG(LS_WARNING) << "Cannot initialize any DxgiOutputDuplicator instance.";
+  }
+
+  return !duplicators_.empty();
 }
 
 void DxgiAdapterDuplicator::Setup(Context* context) {
   RTC_DCHECK(context->contexts.empty());
   context->contexts.resize(duplicators_.size());
   for (size_t i = 0; i < duplicators_.size(); i++) {
     duplicators_[i].Setup(&context->contexts[i]);
   }
 }
 
@@ skipping 47 matching lines @@
 
 void DxgiAdapterDuplicator::TranslateRect(const DesktopVector& position) {
   desktop_rect_.Translate(position);
   RTC_DCHECK(desktop_rect_.left() >= 0 && desktop_rect_.top() >= 0);
   for (auto& duplicator : duplicators_) {
     duplicator.TranslateRect(position);
   }
 }
 
 }  // namespace webrtc