fiber/future/async.hpp

0001
0002 //          Copyright Oliver Kowalke 2013.
0003 // Distributed under the Boost Software License, Version 1.0.
0004 //    (See accompanying file LICENSE_1_0.txt or copy at
0005 //          http://www.boost.org/LICENSE_1_0.txt)
0006
0007 #ifndef BOOST_FIBERS_ASYNC_HPP
0008 #define BOOST_FIBERS_ASYNC_HPP
0009
0010 #include <algorithm>
0011 #include <memory>
0012 #include <type_traits>
0013 #include <utility>
0014
0015 #include <boost/config.hpp>
0016
0017 #include <boost/fiber/future/future.hpp>
0018 #include <boost/fiber/future/packaged_task.hpp>
0019 #include <boost/fiber/policy.hpp>
0020
0021 namespace boost {
0022 namespace fibers {
0023
0024 #if (defined(BOOST_MSVC) && (_MSC_VER >= 1911 && _MSVC_LANG >= 201703)) || __cplusplus >= 202002L
0025 template <typename>
0026 struct result_of;
0027 template <typename F, typename... Args>
0028 struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
0029 #else
0030 using std::result_of;
0031 #endif
0032
0033
0034 template< typename Fn, typename ... Args >
0035 future<
0036     typename result_of<
0037         typename std::enable_if<
0038             ! detail::is_launch_policy< typename std::decay< Fn >::type >::value,
0039             typename std::decay< Fn >::type
0040         >::type( typename std::decay< Args >::type ... )
0041     >::type
0042 >
0043 async( Fn && fn, Args ... args) {
0044     typedef typename result_of<
0045         typename std::decay< Fn >::type( typename std::decay< Args >::type ... )
0046     >::type     result_type;
0047
0048     packaged_task< result_type( typename std::decay< Args >::type ... ) > pt{
0049         std::forward< Fn >( fn) };
0050     future< result_type > f{ pt.get_future() };
0051     fiber{ std::move( pt), std::forward< Args >( args) ... }.detach();
0052     return f;
0053 }
0054
0055 template< typename Policy, typename Fn, typename ... Args >
0056 future<
0057     typename result_of<
0058         typename std::enable_if<
0059             detail::is_launch_policy< Policy >::value,
0060             typename std::decay< Fn >::type
0061         >::type( typename std::decay< Args >::type ...)
0062     >::type
0063 >
0064 async( Policy policy, Fn && fn, Args ... args) {
0065     typedef typename result_of<
0066         typename std::decay< Fn >::type( typename std::decay< Args >::type ... )
0067     >::type     result_type;
0068
0069     packaged_task< result_type( typename std::decay< Args >::type ... ) > pt{
0070         std::forward< Fn >( fn) };
0071     future< result_type > f{ pt.get_future() };
0072     fiber{ policy, std::move( pt), std::forward< Args >( args) ... }.detach();
0073     return f;
0074 }
0075
0076 template< typename Policy, typename StackAllocator, typename Fn, typename ... Args >
0077 future<
0078     typename result_of<
0079         typename std::enable_if<
0080             detail::is_launch_policy< Policy >::value,
0081             typename std::decay< Fn >::type
0082         >::type( typename std::decay< Args >::type ... )
0083     >::type
0084 >
0085 async( Policy policy, std::allocator_arg_t, StackAllocator salloc, Fn && fn, Args ... args) {
0086     typedef typename result_of<
0087         typename std::decay< Fn >::type( typename std::decay< Args >::type ... )
0088     >::type     result_type;
0089
0090     packaged_task< result_type( typename std::decay< Args >::type ... ) > pt{
0091         std::forward< Fn >( fn) };
0092     future< result_type > f{ pt.get_future() };
0093     fiber{ policy, std::allocator_arg, salloc,
0094         std::move( pt), std::forward< Args >( args) ... }.detach();
0095     return f;
0096 }
0097
0098 template< typename Policy, typename StackAllocator, typename Allocator, typename Fn, typename ... Args >
0099 future<
0100     typename result_of<
0101         typename std::enable_if<
0102             detail::is_launch_policy< Policy >::value,
0103             typename std::decay< Fn >::type
0104         >::type( typename std::decay< Args >::type ... )
0105     >::type
0106 >
0107 async( Policy policy, std::allocator_arg_t, StackAllocator salloc, Allocator alloc, Fn && fn, Args ... args) {
0108     typedef typename result_of<
0109         typename std::decay< Fn >::type( typename std::decay< Args >::type ... )
0110     >::type     result_type;
0111
0112     packaged_task< result_type( typename std::decay< Args >::type ... ) > pt{
0113         std::allocator_arg, alloc, std::forward< Fn >( fn) };
0114     future< result_type > f{ pt.get_future() };
0115     fiber{ policy, std::allocator_arg, salloc,
0116         std::move( pt), std::forward< Args >( args) ... }.detach();
0117     return f;
0118 }
0119
0120 }}
0121
0122 #endif // BOOST_FIBERS_ASYNC_HPP