Files
rippled/beast/asio/shared_handler.h
2014-03-19 13:42:05 -07:00

476 lines
11 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef BEAST_ASIO_SHARED_HANDLER_H_INCLUDED
#define BEAST_ASIO_SHARED_HANDLER_H_INCLUDED
#include "../Config.h"
#include "../mpl/IsCallPossible.h"
#include <boost/utility/base_from_member.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_cont_helpers.hpp>
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include "../workaround/noexcept.h"
#include <functional>
#include <memory>
#include "../cxx14/type_traits.h" // <type_traits>
#ifndef BEAST_ASIO_NO_ALLOCATE_SHARED
#define BEAST_ASIO_NO_ALLOCATE_SHARED 0
#endif
#ifndef BEAST_ASIO_NO_HANDLER_RESULT_OF
#define BEAST_ASIO_NO_HANDLER_RESULT_OF 1
#endif
namespace beast {
namespace asio {
class shared_handler_wrapper_base
{
public:
virtual ~shared_handler_wrapper_base()
{
}
virtual void invoke (std::function <void (void)> f) = 0;
virtual void* allocate (std::size_t size) = 0;
virtual void deallocate (void* p, std::size_t size) = 0;
virtual bool is_continuation () = 0;
};
//------------------------------------------------------------------------------
template <class Signature>
class shared_handler_wrapper_func
: public shared_handler_wrapper_base
{
private:
std::function <Signature> m_func;
public:
template <class Handler>
explicit shared_handler_wrapper_func (Handler&& handler)
: m_func (std::ref (std::forward <Handler> (handler)))
{
}
template <class... Args>
#if BEAST_ASIO_NO_HANDLER_RESULT_OF
void
#else
std::result_of_t <std::function <Signature> (Args...)>
#endif
operator() (Args&&... args) const
{
return m_func (std::forward <Args> (args)...);
}
};
//------------------------------------------------------------------------------
namespace detail {
#ifdef _MSC_VER
#pragma warning (push)
#pragma warning (disable: 4512) // assignment operator could not be generated
#endif
template <class Signature, class Handler>
class shared_handler_wrapper
: private boost::base_from_member <Handler>
, public shared_handler_wrapper_func <Signature>
{
private:
typedef boost::base_from_member <Handler> Base;
BEAST_DEFINE_IS_CALL_POSSIBLE(has_is_continuation, is_continuation);
public:
shared_handler_wrapper (Handler&& handler)
: boost::base_from_member <Handler> (std::move (handler))
, shared_handler_wrapper_func <Signature> (Base::member)
{
}
shared_handler_wrapper (Handler const& handler)
: boost::base_from_member <Handler> (handler)
, shared_handler_wrapper_func <Signature> (Base::member)
{
}
private:
void
invoke (std::function <void (void)> f) override
{
return boost_asio_handler_invoke_helpers::
invoke (f, Base::member);
}
void*
allocate (std::size_t size) override
{
return boost_asio_handler_alloc_helpers::
allocate (size, Base::member);
}
void
deallocate (void* p, std::size_t size) override
{
boost_asio_handler_alloc_helpers::
deallocate (p, size, Base::member);
}
bool
is_continuation () override
{
return is_continuation (std::integral_constant <bool,
has_is_continuation <Handler, bool(void)>::value>());
}
bool
is_continuation (std::true_type)
{
return Base::member.is_continuation();
}
bool
is_continuation (std::false_type)
{
return boost_asio_handler_cont_helpers::
is_continuation (Base::member);
}
};
#ifdef _MSC_VER
#pragma warning (pop)
#endif
template <class T>
struct is_shared_handler : public std::false_type
{
};
//------------------------------------------------------------------------------
template <class T, class Handler>
class handler_allocator
{
private:
// We want a partial template specialization as a friend
// but that isn't allowed so we friend all versions. This
// should produce a compile error if Handler is not constructible
// from H.
//
template <class U, class H>
friend class handler_allocator;
Handler m_handler;
public:
typedef T value_type;
typedef T* pointer;
template <class U>
struct rebind
{
public:
typedef handler_allocator <U, Handler> other;
};
handler_allocator() = delete;
handler_allocator (Handler const& handler)
: m_handler (handler)
{
}
template <class U>
handler_allocator (
handler_allocator <U, Handler> const& other)
: m_handler (other.m_handler)
{
}
handler_allocator&
operator= (handler_allocator const&) = delete;
pointer
allocate (std::ptrdiff_t n)
{
auto const size (n * sizeof (T));
return static_cast <pointer> (
boost_asio_handler_alloc_helpers::allocate (
size, m_handler));
}
void
deallocate (pointer p, std::ptrdiff_t n)
{
auto const size (n * sizeof (T));
boost_asio_handler_alloc_helpers::deallocate (
p, size, m_handler);
}
// Work-around for MSVC not using allocator_traits
// in the implementation of shared_ptr
//
#ifdef _MSC_VER
void
destroy (T* t)
{
t->~T();
}
#endif
friend
bool
operator== (handler_allocator const& lhs, handler_allocator const& rhs)
{
return true;
}
friend
bool
operator!= (handler_allocator const& lhs, handler_allocator const& rhs)
{
return ! (lhs == rhs);
}
};
}
//------------------------------------------------------------------------------
/** Handler shared reference that provides io_service execution guarantees. */
template <class Signature>
class shared_handler
{
private:
template <class T>
friend class shared_handler_allocator;
typedef shared_handler_wrapper_func <
Signature> wrapper_type;
typedef std::shared_ptr <wrapper_type> ptr_type;
ptr_type m_ptr;
public:
shared_handler()
{
}
template <
class DeducedHandler,
class = std::enable_if_t <
! detail::is_shared_handler <
std::decay_t <DeducedHandler>>::value &&
std::is_constructible <std::function <Signature>,
std::decay_t <DeducedHandler>>::value
>
>
shared_handler (DeducedHandler&& handler)
{
typedef std::remove_reference_t <DeducedHandler> Handler;
#if BEAST_ASIO_NO_ALLOCATE_SHARED
m_ptr = std::make_shared <detail::shared_handler_wrapper <
Signature, Handler>> (std::forward <DeducedHandler> (handler));
#else
m_ptr = std::allocate_shared <detail::shared_handler_wrapper <
Signature, Handler>> (detail::handler_allocator <char, Handler> (
handler), std::forward <DeducedHandler> (handler));
#endif
}
shared_handler (shared_handler&& other)
: m_ptr (std::move (other.m_ptr))
{
}
shared_handler (shared_handler const& other)
: m_ptr (other.m_ptr)
{
}
shared_handler&
operator= (std::nullptr_t)
{
m_ptr = nullptr;
return *this;
}
shared_handler&
operator= (shared_handler const& rhs)
{
m_ptr = rhs.m_ptr;
return *this;
}
shared_handler&
operator= (shared_handler&& rhs)
{
m_ptr = std::move (rhs.m_ptr);
return *this;
}
explicit
operator bool() const noexcept
{
return m_ptr.operator bool();
}
void
reset()
{
m_ptr.reset();
}
template <class... Args>
#if BEAST_ASIO_NO_HANDLER_RESULT_OF
void
#else
std::result_of_t <std::function <Signature> (Args...)>
#endif
operator() (Args&&... args) const
{
return (*m_ptr)(std::forward <Args> (args)...);
}
template <class Function>
friend
void
asio_handler_invoke (Function&& f, shared_handler* h)
{
return h->m_ptr->invoke (f);
}
friend
void*
asio_handler_allocate (
std::size_t size, shared_handler* h)
{
return h->m_ptr->allocate (size);
}
friend
void
asio_handler_deallocate (
void* p, std::size_t size, shared_handler* h)
{
return h->m_ptr->deallocate (p, size);
}
friend
bool
asio_handler_is_continuation (
shared_handler* h)
{
return h->m_ptr->is_continuation ();
}
};
//------------------------------------------------------------------------------
namespace detail {
template <
class Signature
>
struct is_shared_handler <
shared_handler <Signature>
> : public std::true_type
{
};
}
//------------------------------------------------------------------------------
template <class T>
class shared_handler_allocator
{
private:
template <class U>
friend class shared_handler_allocator;
std::shared_ptr <shared_handler_wrapper_base> m_ptr;
public:
typedef T value_type;
typedef T* pointer;
shared_handler_allocator() = delete;
template <class Signature>
shared_handler_allocator (
shared_handler <Signature> const& handler)
: m_ptr (handler.m_ptr)
{
}
template <class U>
shared_handler_allocator (
shared_handler_allocator <U> const& other)
: m_ptr (other.m_ptr)
{
}
pointer
allocate (std::ptrdiff_t n)
{
auto const size (n * sizeof (T));
return static_cast <pointer> (
m_ptr->allocate (size));
}
void
deallocate (pointer p, std::ptrdiff_t n)
{
auto const size (n * sizeof (T));
m_ptr->deallocate (p, size);
}
friend
bool
operator== (shared_handler_allocator const& lhs,
shared_handler_allocator const& rhs)
{
return lhs.m_ptr == rhs.m_ptr;
}
friend
bool
operator!= (shared_handler_allocator const& lhs,
shared_handler_allocator const& rhs)
{
return ! (lhs == rhs);
}
};
}
}
#endif