git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27408 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
		
			
				
	
	
		
			322 lines
		
	
	
		
			9.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			322 lines
		
	
	
		
			9.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
///////////////////////////////////////////////////////////////////////////////
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// Name:        wx/scopeguard.h
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// Purpose:     declares wxwxScopeGuard and related macros
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// Author:      Vadim Zeitlin
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// Modified by:
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// Created:     03.07.2003
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// RCS-ID:      $Id$
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// Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwidgets.org>
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// Licence:     wxWindows licence
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///////////////////////////////////////////////////////////////////////////////
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/*
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    Acknowledgements: this header is heavily based on (well, almost the exact
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    copy of) wxScopeGuard.h by Andrei Alexandrescu and Petru Marginean published
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    in December 2000 issue of C/C++ Users Journal.
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 */
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#ifndef _WX_SCOPEGUARD_H_
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#define _WX_SCOPEGUARD_H_
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#include "wx/defs.h"
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#include "wx/except.h"
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// ----------------------------------------------------------------------------
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// helpers
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// ----------------------------------------------------------------------------
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namespace wxPrivate
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{
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    // in the original implementation this was a member template function of
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    // ScopeGuardImplBase but gcc 2.8 which is still used for OS/2 doesn't
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    // support member templates and so we must make it global
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    template <typename ScopeGuardImpl>
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    void OnScopeExit(ScopeGuardImpl& guard) 
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    {
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        if ( !guard.WasDismissed() )
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        {
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            // we're called from ScopeGuardImpl dtor and so we must not throw
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            wxTRY
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            {
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                guard.Execute();
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            }
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            wxCATCH_ALL(;) // do nothing, just eat the exception
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        }
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    }
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    // just to avoid the warning about unused variables
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    template <typename T>
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    void Use(const T& WXUNUSED(t))
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    {
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    }
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} // namespace wxPrivate
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// ============================================================================
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// wxScopeGuard for functions and functors
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// ============================================================================
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// ----------------------------------------------------------------------------
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// wxScopeGuardImplBase: used by wxScopeGuardImpl[0..N] below
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// ----------------------------------------------------------------------------
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class wxScopeGuardImplBase
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{
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public:
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    wxScopeGuardImplBase() : m_wasDismissed(false) { }
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    void Dismiss() const { m_wasDismissed = true; }
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    // for OnScopeExit() only we can't make it friend, unfortunately)!
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    bool WasDismissed() const { return m_wasDismissed; }
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protected:
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    ~wxScopeGuardImplBase() { }
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    wxScopeGuardImplBase(const wxScopeGuardImplBase& other) 
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        : m_wasDismissed(other.m_wasDismissed)
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    {
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        other.Dismiss();
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    }
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    // must be mutable for copy ctor to work
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    mutable bool m_wasDismissed;
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private:
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    wxScopeGuardImplBase& operator=(const wxScopeGuardImplBase&);
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};
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// ----------------------------------------------------------------------------
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// wxScopeGuardImpl0: scope guard for actions without parameters
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// ----------------------------------------------------------------------------
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template <typename F>
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class wxScopeGuardImpl0 : public wxScopeGuardImplBase
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{
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public:
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    static wxScopeGuardImpl0<F> MakeGuard(F fun)
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    {
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        return wxScopeGuardImpl0<F>(fun);
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    }
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    ~wxScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { m_fun(); }
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protected:
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    wxScopeGuardImpl0(F fun) : m_fun(fun) { }
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    F m_fun;
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    wxScopeGuardImpl0& operator=(const wxScopeGuardImpl0&);
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};
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template <typename F> 
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inline wxScopeGuardImpl0<F> wxMakeGuard(F fun)
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{
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    return wxScopeGuardImpl0<F>::MakeGuard(fun);
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}
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// ----------------------------------------------------------------------------
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// wxScopeGuardImpl1: scope guard for actions with 1 parameter
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// ----------------------------------------------------------------------------
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template <typename F, typename P1>
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class wxScopeGuardImpl1 : public wxScopeGuardImplBase
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{
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public:
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    static wxScopeGuardImpl1<F, P1> MakeGuard(F fun, P1 p1)
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    {
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        return wxScopeGuardImpl1<F, P1>(fun, p1);
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    }
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    ~wxScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { m_fun(m_p1); }
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protected:
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    wxScopeGuardImpl1(F fun, P1 p1) : m_fun(fun), m_p1(p1) { }
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    F m_fun;
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    const P1 m_p1;
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    wxScopeGuardImpl1& operator=(const wxScopeGuardImpl1&);
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};
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template <typename F, typename P1> 
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inline wxScopeGuardImpl1<F, P1> wxMakeGuard(F fun, P1 p1)
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{
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    return wxScopeGuardImpl1<F, P1>::MakeGuard(fun, p1);
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}
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// ----------------------------------------------------------------------------
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// wxScopeGuardImpl2: scope guard for actions with 2 parameters
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// ----------------------------------------------------------------------------
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template <typename F, typename P1, typename P2>
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class wxScopeGuardImpl2 : public wxScopeGuardImplBase
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{
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public:
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    static wxScopeGuardImpl2<F, P1, P2> MakeGuard(F fun, P1 p1, P2 p2)
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    {
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        return wxScopeGuardImpl2<F, P1, P2>(fun, p1, p2);
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    }
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    ~wxScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { m_fun(m_p1, m_p2); }
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protected:
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    wxScopeGuardImpl2(F fun, P1 p1, P2 p2) : m_fun(fun), m_p1(p1), m_p2(p2) { }
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    F m_fun;
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    const P1 m_p1;
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    const P2 m_p2;
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    wxScopeGuardImpl2& operator=(const wxScopeGuardImpl2&);
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};
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template <typename F, typename P1, typename P2>
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inline wxScopeGuardImpl2<F, P1, P2> wxMakeGuard(F fun, P1 p1, P2 p2)
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{
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    return wxScopeGuardImpl2<F, P1, P2>::MakeGuard(fun, p1, p2);
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}
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// ============================================================================
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// wxScopeGuards for object methods
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// ============================================================================
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// ----------------------------------------------------------------------------
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// wxObjScopeGuardImpl0
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// ----------------------------------------------------------------------------
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template <class Obj, typename MemFun>
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class wxObjScopeGuardImpl0 : public wxScopeGuardImplBase
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{
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public:
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    static wxObjScopeGuardImpl0<Obj, MemFun>
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        MakeObjGuard(Obj& obj, MemFun memFun)
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    {
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        return wxObjScopeGuardImpl0<Obj, MemFun>(obj, memFun);
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    }
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    ~wxObjScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { (m_obj.*m_memfun)(); }
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protected:
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    wxObjScopeGuardImpl0(Obj& obj, MemFun memFun)
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        : m_obj(obj), m_memfun(memFun) { }
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    Obj& m_obj;
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    MemFun m_memfun;
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};
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template <class Obj, typename MemFun>
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inline wxObjScopeGuardImpl0<Obj, MemFun> wxMakeObjGuard(Obj& obj, MemFun memFun)
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{
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    return wxObjScopeGuardImpl0<Obj, MemFun>::MakeObjGuard(obj, memFun);
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}
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template <class Obj, typename MemFun, typename P1>
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class wxObjScopeGuardImpl1 : public wxScopeGuardImplBase
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{
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public:
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    static wxObjScopeGuardImpl1<Obj, MemFun, P1>
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        MakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
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    {
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        return wxObjScopeGuardImpl1<Obj, MemFun, P1>(obj, memFun, p1);
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    }
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    ~wxObjScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { (m_obj.*m_memfun)(m_p1); }
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protected:
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    wxObjScopeGuardImpl1(Obj& obj, MemFun memFun, P1 p1) 
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        : m_obj(obj), m_memfun(memFun), m_p1(p1) { }
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    Obj& m_obj;
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    MemFun m_memfun;
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    const P1 m_p1;
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};
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template <class Obj, typename MemFun, typename P1>
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inline wxObjScopeGuardImpl1<Obj, MemFun, P1>
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wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
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{
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    return wxObjScopeGuardImpl1<Obj, MemFun, P1>::MakeObjGuard(obj, memFun, p1);
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}
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template <class Obj, typename MemFun, typename P1, typename P2>
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class wxObjScopeGuardImpl2 : public wxScopeGuardImplBase
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{
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public:
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    static wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>
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        MakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
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    {
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        return wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>(obj, memFun, p1, p2);
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    }
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    ~wxObjScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); }
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    void Execute() { (m_obj.*m_memfun)(m_p1, m_p2); }
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protected:
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    wxObjScopeGuardImpl2(Obj& obj, MemFun memFun, P1 p1, P2 p2) 
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        : m_obj(obj), m_memfun(memFun), m_p1(p1), m_p2(p2) { }
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    Obj& m_obj;
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    MemFun m_memfun;
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    const P1 m_p1;
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    const P2 m_p2;
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};
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template <class Obj, typename MemFun, typename P1, typename P2>
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inline wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>
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wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
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{
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    return wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>::
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                                            MakeObjGuard(obj, memFun, p1, p2);
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}
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// ============================================================================
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// public stuff
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// ============================================================================
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// wxScopeGuard is just a reference, see the explanation in CUJ article
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typedef const wxScopeGuardImplBase& wxScopeGuard;
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// when an unnamed scope guard is needed, the macros below may be used
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//
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// NB: the original code has a single (and much nicer) ON_BLOCK_EXIT macro
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//     but this results in compiler warnings about unused variables and I
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//     didn't find a way to work around this other than by having different
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//     macros with different names
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#define wxON_BLOCK_EXIT0(f) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeGuard(f); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#define wxON_BLOCK_EXIT_OBJ0(o, m) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeObjGuard(o, m); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#define wxON_BLOCK_EXIT1(f, p1) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeGuard(f, p1); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#define wxON_BLOCK_EXIT_OBJ1(o, m, p1) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeObjGuard(o, m, p1); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#define wxON_BLOCK_EXIT2(f, p1, p2) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeGuard(f, p1, p2); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#define wxON_BLOCK_EXIT_OBJ2(o, m, p1, p2) \
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    wxScopeGuard wxMAKE_UNIQUE_NAME(scopeGuard) = wxMakeObjGuard(o, m, p1, p2); \
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    wxPrivate::Use(wxMAKE_UNIQUE_NAME(scopeGuard))
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#endif // _WX_SCOPEGUARD_H_
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