scoped_com_initializer.h

/////////////////////////////////////////////////////////////////////////////////////////// 
// 
// Copyright (c) 2018 The Authors of ANT(http:://ant.sh) . All Rights Reserved. 
// Use of this source code is governed by a BSD-style license that can be 
// found in the LICENSE file. 
// 
/////////////////////////////////////////////////////////////////////////////////////////// 


#ifndef TEST_UTIL_SCOPED_COM_INITIALIZER_H_
#define TEST_UTIL_SCOPED_COM_INITIALIZER_H_

#include <objbase.h>


// Initializes COM in the constructor (STA or MTA), and uninitializes COM in the
// destructor.
class ScopedCOMInitializer {
 public:
  // Enum value provided to initialize the thread as an MTA instead of STA.
  enum SelectMTA { kMTA };

  // Constructor for STA initialization.
  ScopedCOMInitializer() {
    Initialize(COINIT_APARTMENTTHREADED);
  }

  // Constructor for MTA initialization.
  explicit ScopedCOMInitializer(SelectMTA mta) {
    Initialize(COINIT_MULTITHREADED);
  }

  explicit ScopedCOMInitializer(COINIT init) {
    Initialize(init);
  }

  ~ScopedCOMInitializer() {
#ifndef NDEBUG
    // Using the windows API directly to avoid dependency on platform_thread.
    // DCHECK_EQ(GetCurrentThreadId(), thread_id_);
#endif
    if (succeeded())
      CoUninitialize();
  }

  bool succeeded() const { return SUCCEEDED(hr_); }

 private:
  void Initialize(COINIT init) {
#ifndef NDEBUG
    thread_id_ = GetCurrentThreadId();
#endif
    hr_ = CoInitializeEx(NULL, init);
#ifndef NDEBUG
    //if (hr_ == S_FALSE)
    // LOG(ERROR) << "Multiple CoInitialize() calls for thread " << thread_id_;
    //else
    // DCHECK_NE(RPC_E_CHANGED_MODE, hr_) << "Invalid COM thread model change";
#endif
  }

  HRESULT hr_;
#ifndef NDEBUG
  // In debug builds we use this variable to catch a potential bug where a
  // ScopedCOMInitializer instance is deleted on a different thread than it
  // was initially created on.  If that ever happens it can have bad
  // consequences and the cause can be tricky to track down.
  DWORD thread_id_;
#endif

  DISALLOW_COPY_AND_ASSIGN(ScopedCOMInitializer);
};

#endif  // TEST_UTIL_SCOPED_COM_INITIALIZER_H_