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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
//
// Declares a convenience coclass implementation that makes it easy to create
// initialized object instances.
#ifndef CEEE_COMMON_INITIALIZING_COCLASS_H_
#define CEEE_COMMON_INITIALIZING_COCLASS_H_
#include <atlbase.h>
#include <atlcom.h>
using ATL::CComObject;
// A convenience mixin coclass, to allow creating and initializing
// CComObject<T>-derived object instances, and optionally query them for
// a given interface, all in a single CreateInstance invocation.
//
// Usage:
// <code>
// class MyObjectImpl: public CComObjectRoot<...>,
// public InitializingCoClass<MyObjectImpl>, ... {
// public:
// // This function will be invoked when MyObjectImpl::CreateInstance with N
// // arguments of the appropriate type is invoked.
// // @note if this function returns error, the object will be destroyed
// // @note reference args must be const
// HRESULT Initialize(SomeType1 arg1, ..., SomeTypeN argN);
// };
// ...
// CComPtr<IFoo> foo;
// HRESULT hr = MyObjectImp::CreateInstance(arg1, ..., argN, &foo)
// </code>
//
// @param T the CComObjectRootEx derivative class you want to create and
// initalize.
template <class T>
class InitializingCoClass {
public:
typedef CComObject<T> TImpl;
// Creates an instance of CComObject<T> and initializes it.
// @param new_instance on success returns the new, initialized instance.
// @note this method does not return a reference to the new object.
static HRESULT CreateInstance(T** new_instance) {
TImpl* instance;
HRESULT hr = TImpl::CreateInstance(&instance);
if (FAILED(hr))
return hr;
instance->InternalFinalConstructAddRef();
hr = instance->Initialize();
instance->InternalFinalConstructRelease();
if (FAILED(hr)) {
delete instance;
instance = NULL;
}
*new_instance = instance;
return hr;
}
// Creates an instance of CComObject<T>, initializes it and queries it
// for interface I.
// @param instance on success returns the new, initialized instance.
template <class I>
static HRESULT CreateInitialized(I** instance) {
T* new_instance;
HRESULT hr = CreateInstance(&new_instance);
if (FAILED(hr))
return hr;
hr = new_instance->QueryInterface(__uuidof(I),
reinterpret_cast<void**>(instance));
if (FAILED(hr))
delete new_instance;
return hr;
}
// Creates an instance of CComObject<T>, initializes it and queries it
// for an interface.
// @param iid the interface to query for. Must be congruent to the type I.
// @param instance on success returns the new, initialized instance.
template <class I>
static HRESULT CreateInitializedIID(REFIID iid, I** instance) {
T* new_instance;
HRESULT hr = CreateInstance(&new_instance);
if (FAILED(hr))
return hr;
hr = new_instance->QueryInterface(iid, reinterpret_cast<void**>(instance));
if (FAILED(hr))
delete new_instance;
return hr;
}
// This file is chock full of repetitions of the same code, and because we
// don't yet stock infinite monkeys (nor infinite developers to review their
// code) we substitute with the python script initializing_coclass.py
//
// The functions therein are of this general make:
// Create a new, initialized T* instance. Note that zero references will
// be held to *new_instance at return.
//
// template <class A1, ..., class An>
// HRESULT CreateInstance(A1 a1, ..., An an, T **new_instance);
//
// Create a new, initialized T* instance, and QI it for I
// template <class I, class A1, ..., class An>
// HRESULT CreateInstance(A1 a1, ..., An an, I **new_instance);
#include "initializing_coclass_gen.inl" // NOLINT
};
#ifndef CEEE_COMMON_INITIALIZING_COCLASS_GEN_INL_
#error initializing_coclass_gen.inl wasn't generated correctly.
#endif
#endif // CEEE_COMMON_INITIALIZING_COCLASS_H_
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