Source code of Windows XP (NT5)
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110 lines
2.6 KiB

//
// auto_h.h
//
#pragma once
template<class T> class auto_handle;
template<class T>
class CHandleProxy
{
public:
CHandleProxy (auto_handle<T>& ah) :
m_ah(ah) {};
CHandleProxy (const auto_handle<T>& ah) :
m_ah(const_cast<auto_handle<T>&> (ah)) {};
operator T* () { return &m_ah.h; }
operator const T* () const { return &m_ah.h; }
operator auto_handle<T>* () { return &m_ah; }
protected:
mutable auto_handle<T>& m_ah;
};
template<class T>
class auto_handle
{
public:
auto_handle(T p = 0)
: h(p) {};
auto_handle(const auto_handle<T>& rhs)
: h(rhs.release()) {};
~auto_handle()
{ if (h && INVALID_HANDLE_VALUE != h) CloseHandle(h); };
auto_handle<T>& operator= (const auto_handle<T>& rhs)
{ if (this != rhs.getThis())
reset (rhs.release() );
return *this;
};
auto_handle<T>& operator= (HANDLE rhs)
{ if ((NULL == rhs) || (INVALID_HANDLE_VALUE == rhs))
{
AssertSz(false, "assigning invalid HANDLE to auto_handle- use .reset instead");
// be sure and go through auto_os for dbg.lib
//auto_os os;
//os = (BOOL)FALSE;
//AssertSz(FALSE, "auto_handle<T>::op= Shouldn't ever get here");
}
reset (rhs);
return *this;
};
CHandleProxy<T> operator& ()
{ reset(); return CHandleProxy<T> (*this); }; // &h;
const CHandleProxy<T> operator& () const
{ return CHandleProxy<T> (*this); }; // &h;
operator T ()
{ return h; };
// Checks for NULL
bool operator! ()
{ return h == NULL; }
operator bool()
{ return h != NULL; }
bool operator== (LPVOID lpv) const
{ return h == lpv; };
bool operator!= (LPVOID lpv) const
{ return h != lpv; };
bool operator== (const auto_handle<T>& rhs) const
{ return h == rhs.h; };
bool operator< (const auto_handle<T>& rhs) const
{ return h < rhs.h; };
// return value of current dumb pointer
T get() const
{ return h; };
// relinquish ownership
T release() const
{ T oldh = h;
h = 0;
return oldh;
};
// delete owned pointer; assume ownership of p
BOOL reset (T p = 0)
{
BOOL rt = TRUE;
if (h && INVALID_HANDLE_VALUE != h)
rt = CloseHandle(h);
h = p;
return rt;
};
private:
friend class CHandleProxy<T>;
// operator& throws off operator=
const auto_handle<T> * getThis() const
{ return this; };
// mutable is needed for release call in ctor and copy ctor
mutable T h;
};