130 lines
3.0 KiB
C++
130 lines
3.0 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Name: wx/msw/private/comptr.h
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// Purpose: Smart pointer for COM interfaces.
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// Author: PB
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// Created: 2012-04-16
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// Copyright: (c) 2012 wxWidgets team
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// Licence: wxWindows licence
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///////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_MSW_PRIVATE_COMPTR_H_
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#define _WX_MSW_PRIVATE_COMPTR_H_
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// ----------------------------------------------------------------------------
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// wxCOMPtr: A minimalistic smart pointer for use with COM interfaces.
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// ----------------------------------------------------------------------------
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template <class T>
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class wxCOMPtr
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{
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public:
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typedef T element_type;
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wxCOMPtr()
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: m_ptr(NULL)
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{
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}
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explicit wxCOMPtr(T* ptr)
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: m_ptr(ptr)
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{
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if ( m_ptr )
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m_ptr->AddRef();
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}
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wxCOMPtr(const wxCOMPtr& ptr)
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: m_ptr(ptr.get())
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{
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if ( m_ptr )
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m_ptr->AddRef();
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}
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~wxCOMPtr()
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{
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if ( m_ptr )
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m_ptr->Release();
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}
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void reset(T* ptr = NULL)
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{
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if ( m_ptr != ptr)
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{
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if ( ptr )
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ptr->AddRef();
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if ( m_ptr )
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m_ptr->Release();
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m_ptr = ptr;
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}
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}
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wxCOMPtr& operator=(const wxCOMPtr& ptr)
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{
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reset(ptr.get());
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return *this;
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}
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wxCOMPtr& operator=(T* ptr)
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{
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reset(ptr);
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return *this;
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}
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operator T*() const
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{
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return m_ptr;
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}
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T& operator*() const
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{
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return *m_ptr;
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}
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T* operator->() const
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{
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return m_ptr;
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}
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// It would be better to forbid direct access completely but we do need
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// for QueryInterface() and similar functions, so provide it but it can
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// only be used to initialize the pointer, not to modify an existing one.
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T** operator&()
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{
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wxASSERT_MSG(!m_ptr,
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wxS("Can't get direct access to initialized pointer"));
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return &m_ptr;
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}
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T* get() const
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{
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return m_ptr;
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}
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bool operator<(T* ptr) const
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{
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return get() < ptr;
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}
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private:
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T* m_ptr;
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};
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// Define a helper for the macro below: we just need a function taking a
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// pointer and not returning anything to avoid warnings about unused return
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// value of the cast in the macro itself.
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namespace wxPrivate { inline void PPV_ARGS_CHECK(void*) { } }
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// Takes the interface name and a pointer to a pointer of the interface type
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// and expands into the IID of this interface and the same pointer but after a
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// type-safety check.
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//
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// This is similar to the standard IID_PPV_ARGS macro but takes the pointer
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// type instead of relying on the non-standard Microsoft __uuidof().
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#define wxIID_PPV_ARGS(IType, pType) \
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IID_##IType, \
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(wxPrivate::PPV_ARGS_CHECK(static_cast<IType*>(*pType)), \
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reinterpret_cast<void**>(pType))
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#endif // _WX_MSW_PRIVATE_COMPTR_H_
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