364 lines
11 KiB
C
364 lines
11 KiB
C
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/** \file
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* Wrapper for Win32 API HANDLE.
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*/
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/*
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* Copyright <EFBFBD> 2001,2004 Sofus Mortensen, Michael Geddes
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*
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* This material is provided "as is", with absolutely no warranty
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* expressed or implied. Any use is at your own risk. Permission to
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* use or copy this software for any purpose is hereby granted without
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* fee, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is
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* granted, provided the above notices are retained, and a notice that
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* the code was modified is included with the above copyright notice.
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*
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* This header is part of Comet version 2.
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* https://github.com/alamaison/comet
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*/
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#ifndef COMET_HANDLE_H
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#define COMET_HANDLE_H
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#include <comet/config.h>
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#include <comet/static_assert.h>
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#include <comet/error_fwd.h>
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#include <comet/common.h>
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#include <comet/assert.h>
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#include <algorithm>
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namespace comet {
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/*! \addtogroup COMType
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*/
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//@{
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/** Base and policy class for auto_handle_wrap_t type.
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* This provides the destroy/detach operations for auto_handle_wrap_t as well as
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* providing a base class to contain the handle and to add functions to
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* that are specific to the handle type.
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* \relates auto_handle_wrap_t
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* \sa auto_handle_wrap_t
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*/
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template< typename H, long INVALID_HANDLE_ >
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class handle_policy_base_t
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{
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public:
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/// Default constructor.
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handle_policy_base_t() : handle_(reinterpret_cast<H>(INVALID_HANDLE_)) {}
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explicit handle_policy_base_t( H handle) : handle_(handle) {}
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typedef H value_type;
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//! Implicit conversion to HANDLE
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operator H() const throw()
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{
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// This function seemed not to work with returning a namespaced
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// type.
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return handle_;
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}
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static inline H invalid_handle() { return reinterpret_cast<H>(INVALID_HANDLE_) ;}
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/// Is the handle valid?
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bool valid() const
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{
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return handle_ != invalid_handle();
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}
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/// Detach a raw handle
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H detach_handle()
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{
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return swap_handle(invalid_handle());
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}
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//! Detaches currently held handle without closing it.
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static inline value_type detach( handle_policy_base_t &handle )throw()
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{
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return handle.detach_handle();
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}
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protected:
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/// Destructor to prevent one of these from being created by itself.
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~handle_policy_base_t()
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{ }
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/// Detach the contained handle to the passed in.
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void detach_to(handle_policy_base_t &rhs) throw()
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{
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value_type handle(handle_);
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handle_= invalid_handle();
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rhs.handle_ = handle;
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}
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H get_handle() const { return handle_; }
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H *get_handle_ptr() { return &handle_;}
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H swap_handle(H new_handle)
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{
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H old = handle_;
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handle_ = new_handle;
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return old;
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}
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private:
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H handle_;
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};
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/** \class handle_nothrow_error_policy_t handle.h comet/handle.h
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* Nothrow Error policy.
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* \relates auto_handle_wrap_t
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*/
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struct handle_nothrow_error_policy_t
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{
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static void on_error()
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{ }
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};
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/** \class handle_throw_error_policy_t handle.h comet/handle.h
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* Throwing Error policy.
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* \relates auto_handle_wrap_t
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*/
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struct handle_throw_error_policy_t
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{
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static void on_error()
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{
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DWORD err = GetLastError();
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raise_exception(HRESULT_FROM_WIN32(err));
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}
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};
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/** \class auto_handle_wrap_t handle.h comet/handle.h
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* Wrapper for a Win32 API/GDI HANDLE.
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* Behaves similarly to an auto_ptr in that it implements single-reference,
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* reference counting, with reference-transferring assignment and
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* copy-construction.
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*/
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template<typename C_, typename H, long INVALID_HANDLE_, typename ERROR_POLICY>
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class auto_handle_wrap_t : public handle_policy_base_t<H, INVALID_HANDLE_>
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{
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typedef typename handle_policy_base_t<H, INVALID_HANDLE_>::value_type value_type;
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protected:
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/// Call destroy_handle
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static inline bool destroy_( value_type h)
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{
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return C_::destroy_handle(h);
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}
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/// Destroy the handle passed in.
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/** Must be implemented by the parent class.
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*/
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static bool destroy_handle(value_type h);
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typedef handle_policy_base_t<H, INVALID_HANDLE_> policy_base ;
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void set_handle( value_type h ) throw()
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{
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destroy_(this->swap_handle( h));
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}
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static bool expect_nonzero( BOOL value)
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{
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bool is_ok = (value != FALSE);
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if (!is_ok)
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ERROR_POLICY::on_error();
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return is_ok;
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}
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public:
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/// default constructor.
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auto_handle_wrap_t() throw()
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{}
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/// A reference to a handle.
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typedef const C_ &ref;
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/** Assign by auto_attach.
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*/
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auto_handle_wrap_t( const impl::auto_attach_t<typename policy_base::value_type> &handle ) throw()
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: policy_base(handle.get())
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{}
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/** Non-const copy constructor - takes control of the reference.
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* \param rhs Handle to detach from.
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*/
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auto_handle_wrap_t( auto_handle_wrap_t &rhs) throw()
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{
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rhs.detach_to(*this);
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}
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/** Non-const copy constructor - takes control of the reference.
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* \param rhs Handle to detach from.
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*/
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auto_handle_wrap_t( policy_base &rhs) throw()
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{
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rhs.detach_to(*this);
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}
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/** Destructor - closes the handle.
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*/
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~auto_handle_wrap_t() throw()
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{
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destroy_(get());
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}
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//! Assignment from similar handles.
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/** Typically, there might be a different error policy.
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*/
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template<typename EP>
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auto_handle_wrap_t<C_, H, INVALID_HANDLE_, EP> & operator=(auto_handle_wrap_t<C_, H, INVALID_HANDLE_, EP>& rhs) throw()
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{
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close_handle();
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rhs.detach_to(*this);
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return *this;
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}
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//! Assign by auto_attach
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C_ &operator=(const impl::auto_attach_t<value_type> &handle )
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{
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close_handle();
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set_handle(handle.get());
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return *static_cast<C_ *>(this);
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}
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//! Closes the currently held handle (if any).
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bool close() throw()
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{
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return destroy_(policy_base::detach(*this));
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}
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//! \name Accessor methods
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//@{
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//! Fitter method.
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/*!
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Used when calling a function that take a HANDLE* argument.
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\code
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auto_handle read_pipe, write_pipe;
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CreatePipe(read_pipe.out(), write_pipe.out(), 0, 0));
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\endcode
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*/
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typename policy_base::value_type* out() throw()
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{
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close_handle();
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return this->get_handle_ptr();
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}
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typename policy_base::value_type get() const throw()
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{ return this->get_handle(); }
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typename policy_base::value_type in() const throw()
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{ return this->get_handle(); }
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typename policy_base::value_type *inout() throw()
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{ return this->get_handle_ptr(); }
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//@}
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static inline const C_ &create_const_reference(const value_type &val)
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{ return *reinterpret_cast<const C_ *>(&val); }
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static inline C_ &create_reference(value_type &val)
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{ return *reinterpret_cast<C_ *>(&val); }
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/// Destroy a reference.
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static bool destroy_reference(value_type h)
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{
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return true;
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}
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private:
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//! Closes the currently held handle (if any).
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inline void close_handle()
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{
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if (!close())
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ERROR_POLICY::on_error();
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}
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};
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namespace impl
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{
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/** \internal
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*/
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class THIS_IS_NOT_ALLOWED
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{
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~THIS_IS_NOT_ALLOWED() {}
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};
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}
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/// Disallow closing of a const handle.
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template< typename H, long INVALID_HANDLE_ >
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inline impl::THIS_IS_NOT_ALLOWED CloseHandle(const handle_policy_base_t<H,INVALID_HANDLE_>&);
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/// Make sure closing of an auto_handle_wrap_t detaches first.
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/** \return true if CloseHandle was successful.
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*/
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template< typename H, long INVALID_HANDLE_ >
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bool CloseHandle(handle_policy_base_t<H,INVALID_HANDLE_> &rhs)
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{
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return rhs.close();
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}
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/// Wrapper for HANDLE type
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template< typename ERROR_POLICY = handle_nothrow_error_policy_t >
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struct auto_handle_t : auto_handle_wrap_t< auto_handle_t<ERROR_POLICY>, HANDLE, 0, ERROR_POLICY >
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{
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typedef auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY > handle_base;
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/// Default constructor.
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auto_handle_t() {}
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/// Copy constructor.
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auto_handle_t( auto_handle_t &rhs)
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: auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY >(rhs)
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{}
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/// Auto_attach constructor.
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auto_handle_t( const impl::auto_attach_t< HANDLE > &rhs )
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: auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY >(rhs)
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{ }
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/// Default assignment.
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auto_handle_t &operator=(auto_handle_t &rhs)
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{
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handle_base::operator=(rhs);
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return *this;
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}
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auto_handle_t &operator=( const impl::auto_attach_t<HANDLE> &rhs)
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{
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handle_base::operator=(rhs);
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return *this;
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}
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/// Destroy a handle
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static bool destroy_handle( HANDLE h)
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{
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return ::CloseHandle(h) != FALSE;
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}
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};
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/// Auto handle - wrapper for HANLDE.
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typedef auto_handle_t<> auto_handle;
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/// Auto handle - throwing wrapper for HANDLE.
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typedef auto_handle_t< handle_throw_error_policy_t > auto_handle_throw;
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/// Create a reference object to a handle that doesn't destroy it's contents.
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template <typename T>
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struct auto_reference_t : T
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{
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auto_reference_t( const comet::impl::auto_attach_t<typename T::value_type> &rhs ) : T(rhs)
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{}
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~auto_reference_t()
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{
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destroy_reference(this->detach_handle());
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}
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};
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//@}
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}
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using comet::CloseHandle;
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#endif
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