1 /*
2  *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef RTC_BASE_WIN_GET_ACTIVATION_FACTORY_H_
12 #define RTC_BASE_WIN_GET_ACTIVATION_FACTORY_H_
13 
14 #include <winerror.h>
15 
16 #include "rtc_base/win/hstring.h"
17 
18 namespace webrtc {
19 
20 // Provides access to Core WinRT functions which may not be available on
21 // Windows 7. Loads functions dynamically at runtime to prevent library
22 // dependencies.
23 
24 // Callers must check the return value of ResolveCoreWinRTDelayLoad() before
25 // using these functions.
26 
27 bool ResolveCoreWinRTDelayload();
28 
29 HRESULT RoGetActivationFactoryProxy(HSTRING class_id,
30                                     const IID& iid,
31                                     void** out_factory);
32 
33 // Retrieves an activation factory for the type specified.
34 template <typename InterfaceType, wchar_t const* runtime_class_id>
GetActivationFactory(InterfaceType ** factory)35 HRESULT GetActivationFactory(InterfaceType** factory) {
36   HSTRING class_id_hstring;
37   HRESULT hr = CreateHstring(runtime_class_id, wcslen(runtime_class_id),
38                              &class_id_hstring);
39   if (FAILED(hr))
40     return hr;
41 
42   hr = RoGetActivationFactoryProxy(class_id_hstring, IID_PPV_ARGS(factory));
43   if (FAILED(hr)) {
44     DeleteHstring(class_id_hstring);
45     return hr;
46   }
47 
48   return DeleteHstring(class_id_hstring);
49 }
50 
51 }  // namespace webrtc
52 
53 #endif  // RTC_BASE_WIN_GET_ACTIVATION_FACTORY_H_
54