67 lines
2.0 KiB
C++
67 lines
2.0 KiB
C++
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/* Copyright 2016, Ableton AG, Berlin. All rights reserved.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* If you would like to incorporate Link into a proprietary software application,
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* please contact <link-devs@ableton.com>.
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*/
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#pragma once
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#include <memory>
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namespace ableton
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{
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namespace util
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{
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// A utility handler for passing to async functions that may call the
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// handler past the lifetime of the wrapped delegate object.
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// The need for this is particularly driven by boost::asio timer
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// objects, which explicitly document that they may be called without
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// an error code after they have been cancelled. This has led to
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// several crashes. This handler wrapper implements a useful idiom for
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// avoiding this problem.
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template <typename Delegate>
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struct SafeAsyncHandler
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{
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SafeAsyncHandler(const std::shared_ptr<Delegate>& pDelegate)
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: mpDelegate(pDelegate)
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{
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}
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template <typename... T>
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void operator()(T&&... t) const
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{
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std::shared_ptr<Delegate> pDelegate = mpDelegate.lock();
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if (pDelegate)
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{
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(*pDelegate)(std::forward<T>(t)...);
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}
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}
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std::weak_ptr<Delegate> mpDelegate;
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};
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// Factory function for easily wrapping a shared_ptr to a handler
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template <typename Delegate>
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SafeAsyncHandler<Delegate> makeAsyncSafe(const std::shared_ptr<Delegate>& pDelegate)
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{
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return {pDelegate};
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}
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} // namespace util
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} // namespace ableton
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