wxWidgets/include/wx/scopeguard.h
2003-09-17 16:59:40 +00:00

322 lines
9.7 KiB
C++

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