75 lines
2.0 KiB
C++
75 lines
2.0 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_WIN_SCOPED_COM_INITIALIZER_H_
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#define BASE_WIN_SCOPED_COM_INITIALIZER_H_
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#include <objbase.h>
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#include "base/basictypes.h"
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#include "base/logging.h"
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#include "build/build_config.h"
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namespace base {
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namespace win {
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// Initializes COM in the constructor (STA or MTA), and uninitializes COM in the
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// destructor.
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class ScopedCOMInitializer {
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public:
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// Enum value provided to initialize the thread as an MTA instead of STA.
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enum SelectMTA { kMTA };
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// Constructor for STA initialization.
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ScopedCOMInitializer() {
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Initialize(COINIT_APARTMENTTHREADED);
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}
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// Constructor for MTA initialization.
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explicit ScopedCOMInitializer(SelectMTA mta) {
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Initialize(COINIT_MULTITHREADED);
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}
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~ScopedCOMInitializer() {
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#ifndef NDEBUG
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// Using the windows API directly to avoid dependency on platform_thread.
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DCHECK_EQ(GetCurrentThreadId(), thread_id_);
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#endif
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if (succeeded())
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CoUninitialize();
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}
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bool succeeded() const { return SUCCEEDED(hr_); }
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private:
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void Initialize(COINIT init) {
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#ifndef NDEBUG
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thread_id_ = GetCurrentThreadId();
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#endif
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hr_ = CoInitializeEx(NULL, init);
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#ifndef NDEBUG
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if (hr_ == S_FALSE)
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LOG(ERROR) << "Multiple CoInitialize() calls for thread " << thread_id_;
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else
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DCHECK_NE(RPC_E_CHANGED_MODE, hr_) << "Invalid COM thread model change";
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#endif
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}
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HRESULT hr_;
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#ifndef NDEBUG
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// In debug builds we use this variable to catch a potential bug where a
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// ScopedCOMInitializer instance is deleted on a different thread than it
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// was initially created on. If that ever happens it can have bad
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// consequences and the cause can be tricky to track down.
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DWORD thread_id_;
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#endif
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DISALLOW_COPY_AND_ASSIGN(ScopedCOMInitializer);
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};
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} // namespace win
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} // namespace base
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#endif // BASE_WIN_SCOPED_COM_INITIALIZER_H_
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