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// Copyright Oliver Kowalke 2013.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_FIBERS_PROMISE_HPP
#define BOOST_FIBERS_PROMISE_HPP
#include <algorithm>
#include <memory>
#include <utility>
#include <boost/config.hpp>
#include <boost/core/pointer_traits.hpp>
#include <boost/fiber/exceptions.hpp>
#include <boost/fiber/future/detail/shared_state.hpp>
#include <boost/fiber/future/detail/shared_state_object.hpp>
#include <boost/fiber/future/future.hpp>
namespace boost {
namespace fibers {
namespace detail {
template< typename R >
struct promise_base {
typedef typename shared_state< R >::ptr_type ptr_type;
bool obtained_{ false };
ptr_type future_{};
promise_base() :
promise_base{ std::allocator_arg, std::allocator< promise_base >{} } {
}
template< typename Allocator >
promise_base( std::allocator_arg_t, Allocator alloc) {
typedef detail::shared_state_object< R, Allocator > object_type;
typedef std::allocator_traits< typename object_type::allocator_type > traits_type;
typedef pointer_traits< typename traits_type::pointer > ptrait_type;
typename object_type::allocator_type a{ alloc };
typename traits_type::pointer ptr{ traits_type::allocate( a, 1) };
typename ptrait_type::element_type* p = boost::to_address(ptr);
try {
traits_type::construct( a, p, a);
} catch (...) {
traits_type::deallocate( a, ptr, 1);
throw;
}
future_.reset(p);
}
~promise_base() {
if ( future_ && obtained_) {
future_->owner_destroyed();
}
}
promise_base( promise_base const&) = delete;
promise_base & operator=( promise_base const&) = delete;
promise_base( promise_base && other) noexcept :
obtained_{ other.obtained_ },
future_{ std::move( other.future_) } {
other.obtained_ = false;
}
promise_base & operator=( promise_base && other) noexcept {
if ( BOOST_LIKELY( this != & other) ) {
promise_base tmp{ std::move( other) };
swap( tmp);
}
return * this;
}
future< R > get_future() {
if ( BOOST_UNLIKELY( obtained_) ) {
throw future_already_retrieved{};
}
if ( BOOST_UNLIKELY( ! future_) ) {
throw promise_uninitialized{};
}
obtained_ = true;
return future< R >{ future_ };
}
void swap( promise_base & other) noexcept {
std::swap( obtained_, other.obtained_);
future_.swap( other.future_);
}
void set_exception( std::exception_ptr p) {
if ( BOOST_UNLIKELY( ! future_) ) {
throw promise_uninitialized{};
}
future_->set_exception( p);
}
};
}
template< typename R >
class promise : private detail::promise_base< R > {
private:
typedef detail::promise_base< R > base_type;
public:
promise() = default;
template< typename Allocator >
promise( std::allocator_arg_t, Allocator alloc) :
base_type{ std::allocator_arg, alloc } {
}
promise( promise const&) = delete;
promise & operator=( promise const&) = delete;
promise( promise && other) noexcept = default;
promise & operator=( promise && other) = default;
void set_value( R const& value) {
if ( BOOST_UNLIKELY( ! base_type::future_) ) {
throw promise_uninitialized{};
}
base_type::future_->set_value( value);
}
void set_value( R && value) {
if ( BOOST_UNLIKELY( ! base_type::future_) ) {
throw promise_uninitialized{};
}
base_type::future_->set_value( std::move( value) );
}
void swap( promise & other) noexcept {
base_type::swap( other);
}
using base_type::get_future;
using base_type::set_exception;
};
template< typename R >
class promise< R & > : private detail::promise_base< R & > {
private:
typedef detail::promise_base< R & > base_type;
public:
promise() = default;
template< typename Allocator >
promise( std::allocator_arg_t, Allocator alloc) :
base_type{ std::allocator_arg, alloc } {
}
promise( promise const&) = delete;
promise & operator=( promise const&) = delete;
promise( promise && other) noexcept = default;
promise & operator=( promise && other) noexcept = default;
void set_value( R & value) {
if ( BOOST_UNLIKELY( ! base_type::future_) ) {
throw promise_uninitialized{};
}
base_type::future_->set_value( value);
}
void swap( promise & other) noexcept {
base_type::swap( other);
}
using base_type::get_future;
using base_type::set_exception;
};
template<>
class promise< void > : private detail::promise_base< void > {
private:
typedef detail::promise_base< void > base_type;
public:
promise() = default;
template< typename Allocator >
promise( std::allocator_arg_t, Allocator alloc) :
base_type{ std::allocator_arg, alloc } {
}
promise( promise const&) = delete;
promise & operator=( promise const&) = delete;
promise( promise && other) noexcept = default;
promise & operator=( promise && other) noexcept = default;
inline
void set_value() {
if ( BOOST_UNLIKELY( ! base_type::future_) ) {
throw promise_uninitialized{};
}
base_type::future_->set_value();
}
inline
void swap( promise & other) noexcept {
base_type::swap( other);
}
using base_type::get_future;
using base_type::set_exception;
};
template< typename R >
void swap( promise< R > & l, promise< R > & r) noexcept {
l.swap( r);
}
}}
#endif // BOOST_FIBERS_PROMISE_HPP
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