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126 lines
3.9 KiB
C++
126 lines
3.9 KiB
C++
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/**
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* Copyright 2015 Denis Blank <denis.blank@outlook.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _WEAK_CALLBACK_CONTAINER_H_
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#define _WEAK_CALLBACK_CONTAINER_H_
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#include <unordered_map>
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#include <boost/any.hpp>
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#include <boost/optional.hpp>
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#include "Callback.h"
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class WeakCallbackContainer
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{
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std::shared_ptr<WeakCallbackContainer> self_reference;
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typedef std::size_t handle_t;
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std::size_t _handle;
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std::unordered_map<decltype(_handle), boost::any> _container;
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template<typename _CTy, typename... Args>
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struct ProxyFactory;
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template<typename _CTy, typename... Args>
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struct ProxyFactory<_CTy, ::fu::identity<Args...>>
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{
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// Creates a weak proxy callback which prevents invoking to an invalid context.
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// Removes itself from the owner with the given handler.
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static callback_of_t<_CTy> CreateProxy(std::weak_ptr<WeakCallbackContainer> const& weak_owner,
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std::size_t const _handle, weak_callback_of_t<_CTy> const& weak_callback)
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{
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return [=](Args&&... args)
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{
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// Try to get a pointer to the owner
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if (auto const owner = weak_owner.lock())
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// And to the wrapped functional itself
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if (auto const callback = weak_callback.lock())
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{
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// Invoke the original callback
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(*callback)(std::forward<Args>(args)...);
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// Unregister the callback
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owner->InvalidateCallback(_handle);
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}
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};
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}
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};
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public:
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WeakCallbackContainer()
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: self_reference(this, [](decltype(this)) { }), _handle(0L) { }
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~WeakCallbackContainer() = default;
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WeakCallbackContainer(WeakCallbackContainer const&) = delete;
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WeakCallbackContainer(WeakCallbackContainer&&) = delete;
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WeakCallbackContainer& operator= (WeakCallbackContainer const&) = delete;
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WeakCallbackContainer& operator= (WeakCallbackContainer&&) = delete;
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WeakCallbackContainer& Clear()
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{
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_container.clear();
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return *this;
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}
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/// Weak wraps the given callable.
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template<typename _CTy>
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auto Wrap(_CTy&& callback)
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-> callback_of_t<_CTy>
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{
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// Create the shared callback
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shared_callback_of_t<_CTy> shared_callback = make_shared_callback(std::forward<_CTy>(callback));
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// Create a weak proxy callback which removes the callback on execute
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auto const this_handle = _handle++;
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callback_of_t<_CTy> proxy =
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ProxyFactory<_CTy, ::fu::argument_type_of_t<_CTy>>::
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CreateProxy(self_reference, this_handle, shared_callback);
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_container.insert(std::make_pair(this_handle, boost::any(std::move(shared_callback))));
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return std::move(proxy);
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}
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/// Calls ::Wrap on the given callable,
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template<typename _CTy>
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inline auto operator()(_CTy&& callback)
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-> decltype(Wrap(std::declval<_CTy>()))
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{
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return Wrap(std::forward<_CTy>(callback));
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}
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boost::optional<handle_t> GetLastCallbackHandle() const
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{
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if (_handle == 0L)
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return boost::none;
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else
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return boost::make_optional(_handle);
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}
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WeakCallbackContainer& InvalidateCallback(handle_t const handle)
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{
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_container.erase(handle);
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return *this;
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}
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};
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#endif // _WEAK_CALLBACK_CONTAINER_H_
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