159 lines
3.6 KiB
C++
159 lines
3.6 KiB
C++
//=======================================================================
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//
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// Copyright (c) 1998-1999 Microsoft Corporation. All Rights Reserved.
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//
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// File: ar.h
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//
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// Owner: YanL
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//
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// Description:
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//
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// auto_resource and dirived definitions
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//
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//
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//=======================================================================
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#pragma once
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//----------------------------------------------------------------------
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//
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// class auto_resource
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// This class eliminates need for cleanup when working with pointers and
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// handles of the different kind
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//
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// class _Rh - resource "handle"
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//
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// class _Rh_Traits - required traits for this recource "handle"
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// Should be define as:
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// struct _Rh_Traits {
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// static _Rh invalid() {}
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// static void release(_Rh rh) {}
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// };
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//
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//----------------------------------------------------------------------
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template< class _Rh, class _Rh_Traits >
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class auto_resource {
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public:
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auto_resource(_Rh rh = _Rh_Traits::invalid()) : _r(rh)
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{
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}
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~auto_resource()
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{
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release();
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}
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void release()
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{
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if (valid())
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{
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_Rh_Traits::release(_r);
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_r = _Rh_Traits::invalid();
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}
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}
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const auto_resource& operator=(_Rh rh)
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{
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release();
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_r = rh;
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return *this;
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}
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operator _Rh() const
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{
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return _r;
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}
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_Rh* operator&()
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{
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release();
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return &_r;
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}
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bool valid() const
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{
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return (_Rh_Traits::invalid() != _r);
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}
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_Rh detach()
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{
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_Rh rh = _r;
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_r = _Rh_Traits::invalid();
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return rh;
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}
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protected:
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_Rh _r;
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private:
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// should not use copy constructor etc.
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auto_resource(const auto_resource&) {}
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const auto_resource& operator=(const auto_resource&) {}
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operator bool() const {}
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bool operator !() const {}
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};
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// handle to file has -1 as invalid
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struct auto_hfile_traits {
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static HANDLE invalid() { return INVALID_HANDLE_VALUE; }
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static void release(HANDLE h) { CloseHandle(h); }
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};
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typedef auto_resource< HANDLE, auto_hfile_traits > auto_hfile;
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// handle to all other kernel objects
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struct auto_handle_traits {
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static HANDLE invalid() { return 0; }
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static void release(HANDLE h) { CloseHandle(h); }
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};
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typedef auto_resource< HANDLE, auto_handle_traits > auto_handle;
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// handle to registry key (RegOpenKey, etc.)
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struct auto_hkey_traits {
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static HKEY invalid() { return (HKEY)0; }
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static void release(HKEY hkey) { RegCloseKey(hkey); }
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};
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typedef auto_resource<HKEY, auto_hkey_traits> auto_hkey;
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// handle to SetupDiXxxx registry key - invalid is INVALID_HANDLE_VALUE, not 0
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struct auto_hkeySetupDi_traits {
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static HKEY invalid() { return (HKEY) INVALID_HANDLE_VALUE; }
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static void release(HKEY hkey) { RegCloseKey(hkey); }
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};
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typedef auto_resource<HKEY, auto_hkeySetupDi_traits> auto_hkeySetupDi;
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// handle to load lib key
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struct auto_hlib_traits {
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static HINSTANCE invalid() { return 0; }
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static void release(HINSTANCE hlib) { FreeLibrary(hlib); }
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};
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typedef auto_resource< HINSTANCE, auto_hlib_traits > auto_hlib;
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// auto handle to HANDLE FindFirstFile
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struct auto_hfindfile_traits {
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static HANDLE invalid() { return INVALID_HANDLE_VALUE; }
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static void release(HANDLE hFindFile) { FindClose(hFindFile); }
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};
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typedef auto_resource< HANDLE, auto_hfindfile_traits > auto_hfindfile;
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// Pointer
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template< class _Ty >
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struct auto_pointer_traits {
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static _Ty* invalid() { return 0; }
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static void release(_Ty* p) { delete p; }
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};
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template< class _Ty >
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class auto_pointer : public auto_resource< _Ty*, auto_pointer_traits< _Ty > > {
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public:
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auto_pointer(_Ty* p = 0)
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: auto_resource<_Ty*, auto_pointer_traits< _Ty > >(p)
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{
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}
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const auto_pointer& operator=(_Ty* p)
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{
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auto_resource<_Ty*, auto_pointer_traits< _Ty > >::operator=(p);
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return *this;
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}
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_Ty* operator->() const
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{
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return _r;
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}
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};
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