sustaining_gazes/lib/local/CamCom/comet/handle.h

364 lines
11 KiB
C
Raw Normal View History

2016-05-20 22:48:43 +02:00
/** \file
* Wrapper for Win32 API HANDLE.
*/
/*
* Copyright <EFBFBD> 2001,2004 Sofus Mortensen, Michael Geddes
*
* This material is provided "as is", with absolutely no warranty
* expressed or implied. Any use is at your own risk. Permission to
* use or copy this software for any purpose is hereby granted without
* fee, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is
* granted, provided the above notices are retained, and a notice that
* the code was modified is included with the above copyright notice.
*
* This header is part of Comet version 2.
* https://github.com/alamaison/comet
*/
#ifndef COMET_HANDLE_H
#define COMET_HANDLE_H
#include <comet/config.h>
#include <comet/static_assert.h>
#include <comet/error_fwd.h>
#include <comet/common.h>
#include <comet/assert.h>
#include <algorithm>
namespace comet {
/*! \addtogroup COMType
*/
//@{
/** Base and policy class for auto_handle_wrap_t type.
* This provides the destroy/detach operations for auto_handle_wrap_t as well as
* providing a base class to contain the handle and to add functions to
* that are specific to the handle type.
* \relates auto_handle_wrap_t
* \sa auto_handle_wrap_t
*/
template< typename H, long INVALID_HANDLE_ >
class handle_policy_base_t
{
public:
/// Default constructor.
handle_policy_base_t() : handle_(reinterpret_cast<H>(INVALID_HANDLE_)) {}
explicit handle_policy_base_t( H handle) : handle_(handle) {}
typedef H value_type;
//! Implicit conversion to HANDLE
operator H() const throw()
{
// This function seemed not to work with returning a namespaced
// type.
return handle_;
}
static inline H invalid_handle() { return reinterpret_cast<H>(INVALID_HANDLE_) ;}
/// Is the handle valid?
bool valid() const
{
return handle_ != invalid_handle();
}
/// Detach a raw handle
H detach_handle()
{
return swap_handle(invalid_handle());
}
//! Detaches currently held handle without closing it.
static inline value_type detach( handle_policy_base_t &handle )throw()
{
return handle.detach_handle();
}
protected:
/// Destructor to prevent one of these from being created by itself.
~handle_policy_base_t()
{ }
/// Detach the contained handle to the passed in.
void detach_to(handle_policy_base_t &rhs) throw()
{
value_type handle(handle_);
handle_= invalid_handle();
rhs.handle_ = handle;
}
H get_handle() const { return handle_; }
H *get_handle_ptr() { return &handle_;}
H swap_handle(H new_handle)
{
H old = handle_;
handle_ = new_handle;
return old;
}
private:
H handle_;
};
/** \class handle_nothrow_error_policy_t handle.h comet/handle.h
* Nothrow Error policy.
* \relates auto_handle_wrap_t
*/
struct handle_nothrow_error_policy_t
{
static void on_error()
{ }
};
/** \class handle_throw_error_policy_t handle.h comet/handle.h
* Throwing Error policy.
* \relates auto_handle_wrap_t
*/
struct handle_throw_error_policy_t
{
static void on_error()
{
DWORD err = GetLastError();
raise_exception(HRESULT_FROM_WIN32(err));
}
};
/** \class auto_handle_wrap_t handle.h comet/handle.h
* Wrapper for a Win32 API/GDI HANDLE.
* Behaves similarly to an auto_ptr in that it implements single-reference,
* reference counting, with reference-transferring assignment and
* copy-construction.
*/
template<typename C_, typename H, long INVALID_HANDLE_, typename ERROR_POLICY>
class auto_handle_wrap_t : public handle_policy_base_t<H, INVALID_HANDLE_>
{
typedef typename handle_policy_base_t<H, INVALID_HANDLE_>::value_type value_type;
protected:
/// Call destroy_handle
static inline bool destroy_( value_type h)
{
return C_::destroy_handle(h);
}
/// Destroy the handle passed in.
/** Must be implemented by the parent class.
*/
static bool destroy_handle(value_type h);
typedef handle_policy_base_t<H, INVALID_HANDLE_> policy_base ;
void set_handle( value_type h ) throw()
{
destroy_(this->swap_handle( h));
}
static bool expect_nonzero( BOOL value)
{
bool is_ok = (value != FALSE);
if (!is_ok)
ERROR_POLICY::on_error();
return is_ok;
}
public:
/// default constructor.
auto_handle_wrap_t() throw()
{}
/// A reference to a handle.
typedef const C_ &ref;
/** Assign by auto_attach.
*/
auto_handle_wrap_t( const impl::auto_attach_t<typename policy_base::value_type> &handle ) throw()
: policy_base(handle.get())
{}
/** Non-const copy constructor - takes control of the reference.
* \param rhs Handle to detach from.
*/
auto_handle_wrap_t( auto_handle_wrap_t &rhs) throw()
{
rhs.detach_to(*this);
}
/** Non-const copy constructor - takes control of the reference.
* \param rhs Handle to detach from.
*/
auto_handle_wrap_t( policy_base &rhs) throw()
{
rhs.detach_to(*this);
}
/** Destructor - closes the handle.
*/
~auto_handle_wrap_t() throw()
{
destroy_(get());
}
//! Assignment from similar handles.
/** Typically, there might be a different error policy.
*/
template<typename EP>
auto_handle_wrap_t<C_, H, INVALID_HANDLE_, EP> & operator=(auto_handle_wrap_t<C_, H, INVALID_HANDLE_, EP>& rhs) throw()
{
close_handle();
rhs.detach_to(*this);
return *this;
}
//! Assign by auto_attach
C_ &operator=(const impl::auto_attach_t<value_type> &handle )
{
close_handle();
set_handle(handle.get());
return *static_cast<C_ *>(this);
}
//! Closes the currently held handle (if any).
bool close() throw()
{
return destroy_(policy_base::detach(*this));
}
//! \name Accessor methods
//@{
//! Fitter method.
/*!
Used when calling a function that take a HANDLE* argument.
\code
auto_handle read_pipe, write_pipe;
CreatePipe(read_pipe.out(), write_pipe.out(), 0, 0));
\endcode
*/
typename policy_base::value_type* out() throw()
{
close_handle();
return this->get_handle_ptr();
}
typename policy_base::value_type get() const throw()
{ return this->get_handle(); }
typename policy_base::value_type in() const throw()
{ return this->get_handle(); }
typename policy_base::value_type *inout() throw()
{ return this->get_handle_ptr(); }
//@}
static inline const C_ &create_const_reference(const value_type &val)
{ return *reinterpret_cast<const C_ *>(&val); }
static inline C_ &create_reference(value_type &val)
{ return *reinterpret_cast<C_ *>(&val); }
/// Destroy a reference.
static bool destroy_reference(value_type h)
{
return true;
}
private:
//! Closes the currently held handle (if any).
inline void close_handle()
{
if (!close())
ERROR_POLICY::on_error();
}
};
namespace impl
{
/** \internal
*/
class THIS_IS_NOT_ALLOWED
{
~THIS_IS_NOT_ALLOWED() {}
};
}
/// Disallow closing of a const handle.
template< typename H, long INVALID_HANDLE_ >
inline impl::THIS_IS_NOT_ALLOWED CloseHandle(const handle_policy_base_t<H,INVALID_HANDLE_>&);
/// Make sure closing of an auto_handle_wrap_t detaches first.
/** \return true if CloseHandle was successful.
*/
template< typename H, long INVALID_HANDLE_ >
bool CloseHandle(handle_policy_base_t<H,INVALID_HANDLE_> &rhs)
{
return rhs.close();
}
/// Wrapper for HANDLE type
template< typename ERROR_POLICY = handle_nothrow_error_policy_t >
struct auto_handle_t : auto_handle_wrap_t< auto_handle_t<ERROR_POLICY>, HANDLE, 0, ERROR_POLICY >
{
typedef auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY > handle_base;
/// Default constructor.
auto_handle_t() {}
/// Copy constructor.
auto_handle_t( auto_handle_t &rhs)
: auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY >(rhs)
{}
/// Auto_attach constructor.
auto_handle_t( const impl::auto_attach_t< HANDLE > &rhs )
: auto_handle_wrap_t< auto_handle_t, HANDLE, 0, ERROR_POLICY >(rhs)
{ }
/// Default assignment.
auto_handle_t &operator=(auto_handle_t &rhs)
{
handle_base::operator=(rhs);
return *this;
}
auto_handle_t &operator=( const impl::auto_attach_t<HANDLE> &rhs)
{
handle_base::operator=(rhs);
return *this;
}
/// Destroy a handle
static bool destroy_handle( HANDLE h)
{
return ::CloseHandle(h) != FALSE;
}
};
/// Auto handle - wrapper for HANLDE.
typedef auto_handle_t<> auto_handle;
/// Auto handle - throwing wrapper for HANDLE.
typedef auto_handle_t< handle_throw_error_policy_t > auto_handle_throw;
/// Create a reference object to a handle that doesn't destroy it's contents.
template <typename T>
struct auto_reference_t : T
{
auto_reference_t( const comet::impl::auto_attach_t<typename T::value_type> &rhs ) : T(rhs)
{}
~auto_reference_t()
{
destroy_reference(this->detach_handle());
}
};
//@}
}
using comet::CloseHandle;
#endif