wxWidgets/include/wx/scopeguard.h
Vadim Zeitlin 49b8d79c87 Remove (Open)Watcom support.
This compiler is not being developed since several years and almost certainly
can't be used to build the current wxWidgets sources anyhow, so remove all
support for it, including a lot of extremely ugly workarounds for its bugs
with template functions.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76546 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2014-05-16 13:01:06 +00:00

525 lines
15 KiB
C++

///////////////////////////////////////////////////////////////////////////////
// Name: wx/scopeguard.h
// Purpose: declares wxwxScopeGuard and related macros
// Author: Vadim Zeitlin
// Modified by:
// Created: 03.07.2003
// Copyright: (c) 2003 Vadim Zeitlin <vadim@wxwidgets.org>
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
/*
Acknowledgements: this header is heavily based on (well, almost the exact
copy of) ScopeGuard.h by Andrei Alexandrescu and Petru Marginean published
in December 2000 issue of C/C++ Users Journal.
http://www.cuj.com/documents/cujcexp1812alexandr/
*/
#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 <class 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 <class T>
void Use(const T& WXUNUSED(t))
{
}
} // namespace wxPrivate
#define wxPrivateOnScopeExit(n) wxPrivate::OnScopeExit(n)
#define wxPrivateUse(n) wxPrivate::Use(n)
// ============================================================================
// wxScopeGuard for functions and functors
// ============================================================================
// ----------------------------------------------------------------------------
// wxScopeGuardImplBase: used by wxScopeGuardImpl[0..N] below
// ----------------------------------------------------------------------------
class wxScopeGuardImplBase
{
public:
wxScopeGuardImplBase() : m_wasDismissed(false) { }
wxScopeGuardImplBase(const wxScopeGuardImplBase& other)
: m_wasDismissed(other.m_wasDismissed)
{
other.Dismiss();
}
void Dismiss() const { m_wasDismissed = true; }
// for OnScopeExit() only (we can't make it friend, unfortunately)!
bool WasDismissed() const { return m_wasDismissed; }
protected:
~wxScopeGuardImplBase() { }
// must be mutable for copy ctor to work
mutable bool m_wasDismissed;
private:
wxScopeGuardImplBase& operator=(const wxScopeGuardImplBase&);
};
// wxScopeGuard is just a reference, see the explanation in CUJ article
typedef const wxScopeGuardImplBase& wxScopeGuard;
// ----------------------------------------------------------------------------
// wxScopeGuardImpl0: scope guard for actions without parameters
// ----------------------------------------------------------------------------
template <class F>
class wxScopeGuardImpl0 : public wxScopeGuardImplBase
{
public:
static wxScopeGuardImpl0<F> MakeGuard(F fun)
{
return wxScopeGuardImpl0<F>(fun);
}
~wxScopeGuardImpl0() { wxPrivateOnScopeExit(*this); }
void Execute() { m_fun(); }
protected:
wxScopeGuardImpl0(F fun) : m_fun(fun) { }
F m_fun;
wxScopeGuardImpl0& operator=(const wxScopeGuardImpl0&);
};
template <class F>
inline wxScopeGuardImpl0<F> wxMakeGuard(F fun)
{
return wxScopeGuardImpl0<F>::MakeGuard(fun);
}
// ----------------------------------------------------------------------------
// wxScopeGuardImpl1: scope guard for actions with 1 parameter
// ----------------------------------------------------------------------------
template <class F, class P1>
class wxScopeGuardImpl1 : public wxScopeGuardImplBase
{
public:
static wxScopeGuardImpl1<F, P1> MakeGuard(F fun, P1 p1)
{
return wxScopeGuardImpl1<F, P1>(fun, p1);
}
~wxScopeGuardImpl1() { wxPrivateOnScopeExit(* 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 <class F, class 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 <class F, class P1, class 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() { wxPrivateOnScopeExit(*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 <class F, class P1, class P2>
inline wxScopeGuardImpl2<F, P1, P2> wxMakeGuard(F fun, P1 p1, P2 p2)
{
return wxScopeGuardImpl2<F, P1, P2>::MakeGuard(fun, p1, p2);
}
// ----------------------------------------------------------------------------
// wxScopeGuardImpl3: scope guard for actions with 3 parameters
// ----------------------------------------------------------------------------
template <class F, class P1, class P2, class P3>
class wxScopeGuardImpl3 : public wxScopeGuardImplBase
{
public:
static wxScopeGuardImpl3<F, P1, P2, P3> MakeGuard(F fun, P1 p1, P2 p2, P3 p3)
{
return wxScopeGuardImpl3<F, P1, P2, P3>(fun, p1, p2, p3);
}
~wxScopeGuardImpl3() { wxPrivateOnScopeExit(*this); }
void Execute() { m_fun(m_p1, m_p2, m_p3); }
protected:
wxScopeGuardImpl3(F fun, P1 p1, P2 p2, P3 p3)
: m_fun(fun), m_p1(p1), m_p2(p2), m_p3(p3) { }
F m_fun;
const P1 m_p1;
const P2 m_p2;
const P3 m_p3;
wxScopeGuardImpl3& operator=(const wxScopeGuardImpl3&);
};
template <class F, class P1, class P2, class P3>
inline wxScopeGuardImpl3<F, P1, P2, P3> wxMakeGuard(F fun, P1 p1, P2 p2, P3 p3)
{
return wxScopeGuardImpl3<F, P1, P2, P3>::MakeGuard(fun, p1, p2, p3);
}
// ============================================================================
// wxScopeGuards for object methods
// ============================================================================
// ----------------------------------------------------------------------------
// wxObjScopeGuardImpl0
// ----------------------------------------------------------------------------
template <class Obj, class MemFun>
class wxObjScopeGuardImpl0 : public wxScopeGuardImplBase
{
public:
static wxObjScopeGuardImpl0<Obj, MemFun>
MakeObjGuard(Obj& obj, MemFun memFun)
{
return wxObjScopeGuardImpl0<Obj, MemFun>(obj, memFun);
}
~wxObjScopeGuardImpl0() { wxPrivateOnScopeExit(*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, class MemFun>
inline wxObjScopeGuardImpl0<Obj, MemFun> wxMakeObjGuard(Obj& obj, MemFun memFun)
{
return wxObjScopeGuardImpl0<Obj, MemFun>::MakeObjGuard(obj, memFun);
}
template <class Obj, class MemFun, class 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() { wxPrivateOnScopeExit(*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, class MemFun, class 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, class MemFun, class P1, class 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() { wxPrivateOnScopeExit(*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, class MemFun, class P1, class 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);
}
template <class Obj, class MemFun, class P1, class P2, class P3>
class wxObjScopeGuardImpl3 : public wxScopeGuardImplBase
{
public:
static wxObjScopeGuardImpl3<Obj, MemFun, P1, P2, P3>
MakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2, P3 p3)
{
return wxObjScopeGuardImpl3<Obj, MemFun, P1, P2, P3>(obj, memFun, p1, p2, p3);
}
~wxObjScopeGuardImpl3() { wxPrivateOnScopeExit(*this); }
void Execute() { (m_obj.*m_memfun)(m_p1, m_p2, m_p3); }
protected:
wxObjScopeGuardImpl3(Obj& obj, MemFun memFun, P1 p1, P2 p2, P3 p3)
: m_obj(obj), m_memfun(memFun), m_p1(p1), m_p2(p2), m_p3(p3) { }
Obj& m_obj;
MemFun m_memfun;
const P1 m_p1;
const P2 m_p2;
const P3 m_p3;
};
template <class Obj, class MemFun, class P1, class P2, class P3>
inline wxObjScopeGuardImpl3<Obj, MemFun, P1, P2, P3>
wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2, P3 p3)
{
return wxObjScopeGuardImpl3<Obj, MemFun, P1, P2, P3>::
MakeObjGuard(obj, memFun, p1, p2, p3);
}
// ----------------------------------------------------------------------------
// wxVariableSetter: use the same technique as for wxScopeGuard to allow
// setting a variable to some value on block exit
// ----------------------------------------------------------------------------
namespace wxPrivate
{
// empty class just to be able to define a reference to it
class VariableSetterBase : public wxScopeGuardImplBase { };
typedef const VariableSetterBase& VariableSetter;
template <typename T, typename U>
class VariableSetterImpl : public VariableSetterBase
{
public:
VariableSetterImpl(T& var, U value)
: m_var(var),
m_value(value)
{
}
~VariableSetterImpl() { wxPrivateOnScopeExit(*this); }
void Execute() { m_var = m_value; }
private:
T& m_var;
const U m_value;
// suppress the warning about assignment operator not being generated
VariableSetterImpl<T, U>& operator=(const VariableSetterImpl<T, U>&);
};
template <typename T>
class VariableNullerImpl : public VariableSetterBase
{
public:
VariableNullerImpl(T& var)
: m_var(var)
{
}
~VariableNullerImpl() { wxPrivateOnScopeExit(*this); }
void Execute() { m_var = NULL; }
private:
T& m_var;
VariableNullerImpl<T>& operator=(const VariableNullerImpl<T>&);
};
} // namespace wxPrivate
template <typename T, typename U>
inline
wxPrivate::VariableSetterImpl<T, U> wxMakeVarSetter(T& var, U value)
{
return wxPrivate::VariableSetterImpl<T, U>(var, value);
}
// calling wxMakeVarSetter(ptr, NULL) doesn't work because U is deduced to be
// "int" and subsequent assignment of "U" to "T *" fails, so provide a special
// function for this special case
template <typename T>
inline
wxPrivate::VariableNullerImpl<T> wxMakeVarNuller(T& var)
{
return wxPrivate::VariableNullerImpl<T>(var);
}
// ============================================================================
// macros for declaring unnamed scoped guards (which can't be dismissed)
// ============================================================================
// 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 or using a less natural syntax for passing
// the arguments (e.g. as Boost preprocessor sequences, which would mean
// having to write wxON_BLOCK_EXIT(fwrite, (buf)(size)(n)(fp)) instead of
// wxON_BLOCK_EXIT4(fwrite, buf, size, n, fp)).
#define wxGuardName wxMAKE_UNIQUE_NAME(wxScopeGuard)
#define wxON_BLOCK_EXIT0_IMPL(n, f) \
wxScopeGuard n = wxMakeGuard(f); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT0(f) \
wxON_BLOCK_EXIT0_IMPL(wxGuardName, f)
#define wxON_BLOCK_EXIT_OBJ0_IMPL(n, o, m) \
wxScopeGuard n = wxMakeObjGuard(o, m); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ0(o, m) \
wxON_BLOCK_EXIT_OBJ0_IMPL(wxGuardName, o, &m)
#define wxON_BLOCK_EXIT_THIS0(m) \
wxON_BLOCK_EXIT_OBJ0(*this, m)
#define wxON_BLOCK_EXIT1_IMPL(n, f, p1) \
wxScopeGuard n = wxMakeGuard(f, p1); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT1(f, p1) \
wxON_BLOCK_EXIT1_IMPL(wxGuardName, f, p1)
#define wxON_BLOCK_EXIT_OBJ1_IMPL(n, o, m, p1) \
wxScopeGuard n = wxMakeObjGuard(o, m, p1); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ1(o, m, p1) \
wxON_BLOCK_EXIT_OBJ1_IMPL(wxGuardName, o, &m, p1)
#define wxON_BLOCK_EXIT_THIS1(m, p1) \
wxON_BLOCK_EXIT_OBJ1(*this, m, p1)
#define wxON_BLOCK_EXIT2_IMPL(n, f, p1, p2) \
wxScopeGuard n = wxMakeGuard(f, p1, p2); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT2(f, p1, p2) \
wxON_BLOCK_EXIT2_IMPL(wxGuardName, f, p1, p2)
#define wxON_BLOCK_EXIT_OBJ2_IMPL(n, o, m, p1, p2) \
wxScopeGuard n = wxMakeObjGuard(o, m, p1, p2); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ2(o, m, p1, p2) \
wxON_BLOCK_EXIT_OBJ2_IMPL(wxGuardName, o, &m, p1, p2)
#define wxON_BLOCK_EXIT_THIS2(m, p1, p2) \
wxON_BLOCK_EXIT_OBJ2(*this, m, p1, p2)
#define wxON_BLOCK_EXIT3_IMPL(n, f, p1, p2, p3) \
wxScopeGuard n = wxMakeGuard(f, p1, p2, p3); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT3(f, p1, p2, p3) \
wxON_BLOCK_EXIT3_IMPL(wxGuardName, f, p1, p2, p3)
#define wxON_BLOCK_EXIT_OBJ3_IMPL(n, o, m, p1, p2, p3) \
wxScopeGuard n = wxMakeObjGuard(o, m, p1, p2, p3); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ3(o, m, p1, p2, p3) \
wxON_BLOCK_EXIT_OBJ3_IMPL(wxGuardName, o, &m, p1, p2, p3)
#define wxON_BLOCK_EXIT_THIS3(m, p1, p2, p3) \
wxON_BLOCK_EXIT_OBJ3(*this, m, p1, p2, p3)
#define wxSetterName wxMAKE_UNIQUE_NAME(wxVarSetter)
#define wxON_BLOCK_EXIT_SET_IMPL(n, var, value) \
wxPrivate::VariableSetter n = wxMakeVarSetter(var, value); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_SET(var, value) \
wxON_BLOCK_EXIT_SET_IMPL(wxSetterName, var, value)
#define wxON_BLOCK_EXIT_NULL_IMPL(n, var) \
wxPrivate::VariableSetter n = wxMakeVarNuller(var); \
wxPrivateUse(n)
#define wxON_BLOCK_EXIT_NULL(ptr) \
wxON_BLOCK_EXIT_NULL_IMPL(wxSetterName, ptr)
#endif // _WX_SCOPEGUARD_H_