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/*
* Copyright (c) 2020 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.
*/
#ifndef RTC_BASE_WIN_SCOPED_COM_INITIALIZER_H_
#define RTC_BASE_WIN_SCOPED_COM_INITIALIZER_H_
#include <comdef.h>
namespace webrtc {
// Initializes COM in the constructor (STA or MTA), and uninitializes COM in the
// destructor. Taken from base::win::ScopedCOMInitializer.
//
// WARNING: This should only be used once per thread, ideally scoped to a
// similar lifetime as the thread itself. You should not be using this in
// random utility functions that make COM calls; instead ensure that these
// functions are running on a COM-supporting thread!
// See https://msdn.microsoft.com/en-us/library/ms809971.aspx for details.
class ScopedCOMInitializer {
public:
// Enum value provided to initialize the thread as an MTA instead of STA.
// There are two types of apartments, Single Threaded Apartments (STAs)
// and Multi Threaded Apartments (MTAs). Within a given process there can
// be multiple STA’s but there is only one MTA. STA is typically used by
// "GUI applications" and MTA by "worker threads" with no UI message loop.
enum SelectMTA { kMTA };
// Constructor for STA initialization.
ScopedCOMInitializer();
// Constructor for MTA initialization.
explicit ScopedCOMInitializer(SelectMTA mta);
~ScopedCOMInitializer();
ScopedCOMInitializer(const ScopedCOMInitializer&) = delete;
ScopedCOMInitializer& operator=(const ScopedCOMInitializer&) = delete;
bool Succeeded() { return SUCCEEDED(hr_); }
private:
void Initialize(COINIT init);
HRESULT hr_;
};
} // namespace webrtc
#endif // RTC_BASE_WIN_SCOPED_COM_INITIALIZER_H_
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