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- //
- // impl/executor.hpp
- // ~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
- //
- // 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 ASIO_IMPL_EXECUTOR_HPP
- #define ASIO_IMPL_EXECUTOR_HPP
-
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
-
- #include "asio/detail/config.hpp"
- #include "asio/detail/atomic_count.hpp"
- #include "asio/detail/executor_function.hpp"
- #include "asio/detail/global.hpp"
- #include "asio/detail/memory.hpp"
- #include "asio/detail/recycling_allocator.hpp"
- #include "asio/executor.hpp"
- #include "asio/system_executor.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
-
- #if !defined(GENERATING_DOCUMENTATION)
-
- #if defined(ASIO_HAS_MOVE)
-
- // Lightweight, move-only function object wrapper.
- class executor::function
- {
- public:
- template <typename F, typename Alloc>
- explicit function(F f, const Alloc& a)
- {
- // Allocate and construct an operation to wrap the function.
- typedef detail::executor_function<F, Alloc> func_type;
- typename func_type::ptr p = {
- detail::addressof(a), func_type::ptr::allocate(a), 0 };
- func_ = new (p.v) func_type(ASIO_MOVE_CAST(F)(f), a);
- p.v = 0;
- }
-
- function(function&& other) ASIO_NOEXCEPT
- : func_(other.func_)
- {
- other.func_ = 0;
- }
-
- ~function()
- {
- if (func_)
- func_->destroy();
- }
-
- void operator()()
- {
- if (func_)
- {
- detail::executor_function_base* func = func_;
- func_ = 0;
- func->complete();
- }
- }
-
- private:
- detail::executor_function_base* func_;
- };
-
- #else // defined(ASIO_HAS_MOVE)
-
- // Not so lightweight, copyable function object wrapper.
- class executor::function
- {
- public:
- template <typename F, typename Alloc>
- explicit function(const F& f, const Alloc&)
- : impl_(new impl<F>(f))
- {
- }
-
- void operator()()
- {
- impl_->invoke_(impl_.get());
- }
-
- private:
- // Base class for polymorphic function implementations.
- struct impl_base
- {
- void (*invoke_)(impl_base*);
- };
-
- // Polymorphic function implementation.
- template <typename F>
- struct impl : impl_base
- {
- impl(const F& f)
- : function_(f)
- {
- invoke_ = &function::invoke<F>;
- }
-
- F function_;
- };
-
- // Helper to invoke a function.
- template <typename F>
- static void invoke(impl_base* i)
- {
- static_cast<impl<F>*>(i)->function_();
- }
-
- detail::shared_ptr<impl_base> impl_;
- };
-
- #endif // defined(ASIO_HAS_MOVE)
-
- // Default polymorphic allocator implementation.
- template <typename Executor, typename Allocator>
- class executor::impl
- : public executor::impl_base
- {
- public:
- typedef ASIO_REBIND_ALLOC(Allocator, impl) allocator_type;
-
- static impl_base* create(const Executor& e, Allocator a = Allocator())
- {
- raw_mem mem(a);
- impl* p = new (mem.ptr_) impl(e, a);
- mem.ptr_ = 0;
- return p;
- }
-
- impl(const Executor& e, const Allocator& a) ASIO_NOEXCEPT
- : impl_base(false),
- ref_count_(1),
- executor_(e),
- allocator_(a)
- {
- }
-
- impl_base* clone() const ASIO_NOEXCEPT
- {
- ++ref_count_;
- return const_cast<impl_base*>(static_cast<const impl_base*>(this));
- }
-
- void destroy() ASIO_NOEXCEPT
- {
- if (--ref_count_ == 0)
- {
- allocator_type alloc(allocator_);
- impl* p = this;
- p->~impl();
- alloc.deallocate(p, 1);
- }
- }
-
- void on_work_started() ASIO_NOEXCEPT
- {
- executor_.on_work_started();
- }
-
- void on_work_finished() ASIO_NOEXCEPT
- {
- executor_.on_work_finished();
- }
-
- execution_context& context() ASIO_NOEXCEPT
- {
- return executor_.context();
- }
-
- void dispatch(ASIO_MOVE_ARG(function) f)
- {
- executor_.dispatch(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- void post(ASIO_MOVE_ARG(function) f)
- {
- executor_.post(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- void defer(ASIO_MOVE_ARG(function) f)
- {
- executor_.defer(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- type_id_result_type target_type() const ASIO_NOEXCEPT
- {
- return type_id<Executor>();
- }
-
- void* target() ASIO_NOEXCEPT
- {
- return &executor_;
- }
-
- const void* target() const ASIO_NOEXCEPT
- {
- return &executor_;
- }
-
- bool equals(const impl_base* e) const ASIO_NOEXCEPT
- {
- if (this == e)
- return true;
- if (target_type() != e->target_type())
- return false;
- return executor_ == *static_cast<const Executor*>(e->target());
- }
-
- private:
- mutable detail::atomic_count ref_count_;
- Executor executor_;
- Allocator allocator_;
-
- struct raw_mem
- {
- allocator_type allocator_;
- impl* ptr_;
-
- explicit raw_mem(const Allocator& a)
- : allocator_(a),
- ptr_(allocator_.allocate(1))
- {
- }
-
- ~raw_mem()
- {
- if (ptr_)
- allocator_.deallocate(ptr_, 1);
- }
-
- private:
- // Disallow copying and assignment.
- raw_mem(const raw_mem&);
- raw_mem operator=(const raw_mem&);
- };
- };
-
- // Polymorphic allocator specialisation for system_executor.
- template <typename Allocator>
- class executor::impl<system_executor, Allocator>
- : public executor::impl_base
- {
- public:
- static impl_base* create(const system_executor&,
- const Allocator& = Allocator())
- {
- return &detail::global<impl<system_executor, std::allocator<void> > >();
- }
-
- impl()
- : impl_base(true)
- {
- }
-
- impl_base* clone() const ASIO_NOEXCEPT
- {
- return const_cast<impl_base*>(static_cast<const impl_base*>(this));
- }
-
- void destroy() ASIO_NOEXCEPT
- {
- }
-
- void on_work_started() ASIO_NOEXCEPT
- {
- executor_.on_work_started();
- }
-
- void on_work_finished() ASIO_NOEXCEPT
- {
- executor_.on_work_finished();
- }
-
- execution_context& context() ASIO_NOEXCEPT
- {
- return executor_.context();
- }
-
- void dispatch(ASIO_MOVE_ARG(function) f)
- {
- executor_.dispatch(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- void post(ASIO_MOVE_ARG(function) f)
- {
- executor_.post(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- void defer(ASIO_MOVE_ARG(function) f)
- {
- executor_.defer(ASIO_MOVE_CAST(function)(f), allocator_);
- }
-
- type_id_result_type target_type() const ASIO_NOEXCEPT
- {
- return type_id<system_executor>();
- }
-
- void* target() ASIO_NOEXCEPT
- {
- return &executor_;
- }
-
- const void* target() const ASIO_NOEXCEPT
- {
- return &executor_;
- }
-
- bool equals(const impl_base* e) const ASIO_NOEXCEPT
- {
- return this == e;
- }
-
- private:
- system_executor executor_;
- Allocator allocator_;
- };
-
- template <typename Executor>
- executor::executor(Executor e)
- : impl_(impl<Executor, std::allocator<void> >::create(e))
- {
- }
-
- template <typename Executor, typename Allocator>
- executor::executor(allocator_arg_t, const Allocator& a, Executor e)
- : impl_(impl<Executor, Allocator>::create(e, a))
- {
- }
-
- template <typename Function, typename Allocator>
- void executor::dispatch(ASIO_MOVE_ARG(Function) f,
- const Allocator& a) const
- {
- impl_base* i = get_impl();
- if (i->fast_dispatch_)
- system_executor().dispatch(ASIO_MOVE_CAST(Function)(f), a);
- else
- i->dispatch(function(ASIO_MOVE_CAST(Function)(f), a));
- }
-
- template <typename Function, typename Allocator>
- void executor::post(ASIO_MOVE_ARG(Function) f,
- const Allocator& a) const
- {
- get_impl()->post(function(ASIO_MOVE_CAST(Function)(f), a));
- }
-
- template <typename Function, typename Allocator>
- void executor::defer(ASIO_MOVE_ARG(Function) f,
- const Allocator& a) const
- {
- get_impl()->defer(function(ASIO_MOVE_CAST(Function)(f), a));
- }
-
- template <typename Executor>
- Executor* executor::target() ASIO_NOEXCEPT
- {
- return impl_ && impl_->target_type() == type_id<Executor>()
- ? static_cast<Executor*>(impl_->target()) : 0;
- }
-
- template <typename Executor>
- const Executor* executor::target() const ASIO_NOEXCEPT
- {
- return impl_ && impl_->target_type() == type_id<Executor>()
- ? static_cast<Executor*>(impl_->target()) : 0;
- }
-
- #endif // !defined(GENERATING_DOCUMENTATION)
-
- } // namespace asio
-
- #include "asio/detail/pop_options.hpp"
-
- #endif // ASIO_IMPL_EXECUTOR_HPP
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