5551932c25
Using Bind() with a method of the class deriving from wxEvtHandler non-publicly used to result in a compile-time error, but at least with C++11 we can detect this case and allow the code to compile. Closes #17623.
61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: wx/meta/convertible.h
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// Purpose: Test if types are convertible
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// Author: Arne Steinarson
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// Created: 2008-01-10
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// Copyright: (c) 2008 Arne Steinarson
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_META_CONVERTIBLE_H_
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#define _WX_META_CONVERTIBLE_H_
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//
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// Introduce an extra class to make this header compilable with g++3.2
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//
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template <class D, class B>
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struct wxConvertibleTo_SizeHelper
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{
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static char Match(B* pb);
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static int Match(...);
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};
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// Helper to decide if an object of type D is convertible to type B (the test
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// succeeds in particular when D derives from B)
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template <class D, class B>
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struct wxConvertibleTo
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{
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enum
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{
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value =
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sizeof(wxConvertibleTo_SizeHelper<D,B>::Match(static_cast<D*>(NULL)))
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==
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sizeof(char)
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};
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};
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// This is similar to wxConvertibleTo, except that when using a C++11 compiler,
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// the case of D deriving from B non-publicly will be detected and the correct
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// value (false) will be deduced instead of getting a compile-time error as
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// with wxConvertibleTo. For pre-C++11 compilers there is no difference between
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// this helper and wxConvertibleTo.
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template <class D, class B>
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struct wxIsPubliclyDerived
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{
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enum
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{
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#if __cplusplus >= 201103 || (defined(_MSC_VER) && _MSC_VER >= 1600)
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// If C++11 is available we use this, as on most compilers it's a
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// built-in and will be evaluated at compile-time.
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value = std::is_base_of<B, D>::value && std::is_convertible<D*, B*>::value
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#else
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// When not using C++11, we fall back to wxConvertibleTo, which fails
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// at compile-time if D doesn't publicly derive from B.
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value = wxConvertibleTo<D, B>::value
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#endif
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};
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};
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#endif // _WX_META_CONVERTIBLE_H_
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