Ichthyostega
685be1b039
This is Step-2 : change the API towards application Notably all invocation variants to support member functions or a reference to bool flags are retracted, since today a λ-binding directly at usage site tends to be more readable. The function names are harmonised with the C++ standard and emergency shutdown in the Subsystem-Runner is rationalised. The old thread-wrapper test is repurposed to demonstrate the effectiveness of monitor based locking.
122 lines
3.1 KiB
C++
122 lines
3.1 KiB
C++
/*
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CALL-QUEUE.hpp - a queue to dispatch bound function invocations into another thread
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Copyright (C) Lumiera.org
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2017, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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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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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file call-queue.hpp
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** A Queue for function invocations, allowing them to be dispatched on demand.
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** Typically this queue helper is used to forward lambdas into another thread, e.g.
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** the UI thread for execution.
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**
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** @todo simplistic braindead implementation with locking and heap based storage
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** based on std::function; should use a lock-fee queue and should have an eye
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** on the impact of managing argument storage
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**
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** @see stage::NotificationService usage example
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*/
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#ifndef LIB_CALL_QUEUE_H
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#define LIB_CALL_QUEUE_H
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#include "lib/error.hpp"
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#include "lib/sync.hpp"
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#include "lib/iter-stack.hpp"
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#include "lib/nocopy.hpp"
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#include <functional>
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namespace lib {
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namespace error = lumiera::error;
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/*********************************************************//**
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* A threadsafe queue for bound `void(void)` functors.
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* Typically used to dispatch function invocations together with
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* their concrete parameters into another thread for invocation.
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*/
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class CallQueue
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: util::NonCopyable
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, public Sync<>
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{
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public:
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using Operation = std::function<void(void)>;
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private:
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lib::IterQueue<Operation> queue_;
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public:
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CallQueue() { }
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CallQueue&
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feed (Operation&& op)
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{
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if (not op)
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throw error::Logic( "Unbound Functor fed to dispatcher CallQueue"
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, error::LUMIERA_ERROR_BOTTOM_VALUE);
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{
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Lock sync{this};
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queue_.feed (move(op));
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}
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return *this;
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}
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CallQueue&
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invoke()
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{
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if (not empty())
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{
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Operation operate;
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{
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Lock sync{this};
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operate = move (*queue_);
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++queue_;
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}
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ASSERT (operate);
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operate();
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}
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return *this;
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}
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/* == diagnostics == */
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size_t
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size() const
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{
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Lock sync{this};
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return queue_.size();
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}
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bool
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empty() const
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{
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return 0 == size();
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}
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};
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} // namespace lib
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#endif /*LIB_CALL_QUEUE_H*/
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