/*
Acknowledgements: this header is heavily based on (well, almost the exact
- copy of) wxScopeGuard.h by Andrei Alexandrescu and Petru Marginean published
+ 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_
// helpers
// ----------------------------------------------------------------------------
+#ifdef __WATCOMC__
+
+// WATCOM-FIXME: C++ of Open Watcom 1.3 doesn't like OnScopeExit() created
+// through template so it must be workarounded with dedicated inlined macro.
+// For compatibility with Watcom compilers wxPrivate::OnScopeExit must be
+// replaced with wxPrivateOnScopeExit but in user code (for everyone who
+// doesn't care about OW compatibility) wxPrivate::OnScopeExit still works.
+
+#define wxPrivateOnScopeExit(guard) \
+ { \
+ if ( !(guard).WasDismissed() ) \
+ { \
+ wxTRY \
+ { \
+ (guard).Execute(); \
+ } \
+ wxCATCH_ALL(;) \
+ } \
+ }
+
+#define wxPrivateUse(n) wxUnusedVar(n)
+
+#else
+
+// namespace support was first implemented in gcc-2.95,
+// so avoid using it for older versions.
+#if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95)
+
+#define wxHAS_NAMESPACES
+
namespace wxPrivate
{
+#else
+#define wxPrivate
+#endif
// 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
void Use(const T& WXUNUSED(t))
{
}
+#if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95)
} // namespace wxPrivate
+#endif
+
+#define wxPrivateOnScopeExit(n) wxPrivate::OnScopeExit(n)
+#define wxPrivateUse(n) wxPrivate::Use(n)
+
+#endif
// ============================================================================
// wxScopeGuard for functions and functors
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)!
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;
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
// ----------------------------------------------------------------------------
return wxScopeGuardImpl0<F>(fun);
}
- ~wxScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); }
+ ~wxScopeGuardImpl0() { wxPrivateOnScopeExit(*this); }
void Execute() { m_fun(); }
return wxScopeGuardImpl1<F, P1>(fun, p1);
}
- ~wxScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); }
+ ~wxScopeGuardImpl1() { wxPrivateOnScopeExit(* this); }
void Execute() { m_fun(m_p1); }
return wxScopeGuardImpl2<F, P1, P2>(fun, p1, p2);
}
- ~wxScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); }
+ ~wxScopeGuardImpl2() { wxPrivateOnScopeExit(*this); }
void Execute() { m_fun(m_p1, m_p2); }
return wxObjScopeGuardImpl0<Obj, MemFun>(obj, memFun);
}
- ~wxObjScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); }
+ ~wxObjScopeGuardImpl0() { wxPrivateOnScopeExit(*this); }
void Execute() { (m_obj.*m_memfun)(); }
return wxObjScopeGuardImpl1<Obj, MemFun, P1>(obj, memFun, p1);
}
- ~wxObjScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); }
+ ~wxObjScopeGuardImpl1() { wxPrivateOnScopeExit(*this); }
void Execute() { (m_obj.*m_memfun)(m_p1); }
return wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>(obj, memFun, p1, p2);
}
- ~wxObjScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); }
+ ~wxObjScopeGuardImpl2() { wxPrivateOnScopeExit(*this); }
void Execute() { (m_obj.*m_memfun)(m_p1, m_p2); }
MakeObjGuard(obj, memFun, p1, p2);
}
+// ----------------------------------------------------------------------------
+// wxVariableSetter: use the same technique as for wxScopeGuard to allow
+// setting a variable to some value on block exit
+// ----------------------------------------------------------------------------
+
+#ifdef wxHAS_NAMESPACES
+
+namespace wxPrivate
+{
+
+// empty class just to be able to define a reference to it
+class VariableSetterBase { };
+
+typedef const VariableSetterBase& VariableSetter;
+
+template <typename T, typename U>
+class VariableSetterImpl : public VariableSetterBase
+{
+public:
+ VariableSetterImpl(T& var, const U& value)
+ : m_var(var),
+ m_value(value)
+ {
+ }
+
+ ~VariableSetterImpl()
+ {
+ 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()
+ {
+ 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, const 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);
+}
+
+#endif // wxHAS_NAMESPACES
+
// ============================================================================
-// public stuff
+// macros for declaring unnamed scoped guards (which can't be dismissed)
// ============================================================================
-// 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
+// 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(scopeGuard)
+#define wxGuardName wxMAKE_UNIQUE_NAME(wxScopeGuard)
#define wxON_BLOCK_EXIT0_IMPL(n, f) \
wxScopeGuard n = wxMakeGuard(f); \
- wxPrivate::Use(n)
+ 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); \
- wxPrivate::Use(n)
+ wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ0(o, m) \
- wxON_BLOCK_EXIT_OBJ0_IMPL(wxGuardName, 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); \
- wxPrivate::Use(n)
+ 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); \
- wxPrivate::Use(n)
+ wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ1(o, m, p1) \
- wxON_BLOCK_EXIT_OBJ1_IMPL(wxGuardName, 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); \
- wxPrivate::Use(n)
+ 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); \
- wxPrivate::Use(n)
+ wxPrivateUse(n)
#define wxON_BLOCK_EXIT_OBJ2(o, m, p1, p2) \
- wxON_BLOCK_EXIT_OBJ2_IMPL(wxGuardName, 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 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_
projects / wxWidgets.git / blobdiff