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| -rw-r--r-- | slideshow/source/inc/interruptabledelayevent.hxx | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/slideshow/source/inc/interruptabledelayevent.hxx b/slideshow/source/inc/interruptabledelayevent.hxx new file mode 100644 index 000000000..a877e206f --- /dev/null +++ b/slideshow/source/inc/interruptabledelayevent.hxx @@ -0,0 +1,140 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ + +#ifndef INCLUDED_SLIDESHOW_SOURCE_INC_INTERRUPTABLEDELAYEVENT_HXX +#define INCLUDED_SLIDESHOW_SOURCE_INC_INTERRUPTABLEDELAYEVENT_HXX + +#include "delayevent.hxx" + +namespace slideshow::internal + { + /** Event, which delays calling passed Event's fire() method + the given amount of time. + + This is actually a facade around the passed event object, + that passes on all calls to that object, and the sole + contribution of itself is the delay. + */ + class DelayFacade : public Event + { + public: + DelayFacade( const EventSharedPtr& rEvent, + double nTimeout ) : + Event("DelayFacade"), + mpEvent( rEvent ), + mnTimeout( nTimeout ) + { + } + + virtual bool fire() override + { + if( mpEvent && isCharged() ) + { + // pass on directly - we're supposed to be called + // from EventQueue here, anyway - and if not, + // we're only keeping that incorrect transitively. + return mpEvent->fire(); + } + + return false; + } + + virtual bool isCharged() const override + { + // pass on to wrappee - this ensures that we return + // false on isCharged(), even if the other event has + // been fired outside our own fire() method + return mpEvent && mpEvent->isCharged(); + } + + virtual double getActivationTime( double nCurrentTime ) const override + { + // enforce _our_ timeout to our clients (this + // overrides any timeout possibly set at the wrappee!) + return nCurrentTime + mnTimeout; + } + + virtual void dispose() override + { + mpEvent.reset(); + } + + private: + EventSharedPtr mpEvent; + double mnTimeout; + }; + + /// Return value for makeInterruptableDelay() + struct InterruptableEventPair + { + /** This member contains a pointer to the timeout + event. When enqueued, this event will fire the + requested action only after the specified timeout. + */ + EventSharedPtr mpTimeoutEvent; + + /** This member contains a pointer to the interruption + event. When enqueued, this event will fire + immediately, interrupting a potentially waiting + timeout event. + */ + EventSharedPtr mpImmediateEvent; + }; + + /** Generate an interruptable delay event. + + This function generates a pair of events, that are + especially tailored to achieve the following behaviour: By + default, the given functor is called after the specified + timeout (after insertion of the event into the EventQueue, + of course). But optionally, when the interruption event + InterruptableEventPair::mpImmediateEvent is fired, the + given functor is called <em>at once</em>, and the delay is + ignored (that means, the given functor is guaranteed to be + called at utmost once, and never twice. Furthermore, it is + ensured that both events return false on isCharged(), once + anyone of them has been fired already). + + @param rFunctor + Functor to call when the event fires. + + @param nTimeout + Timeout in seconds, to wait until functor is called. + + @returns a pair of events, where the first one waits the + specified amount of time, and the other fires the given + functor immediately. + */ + template< typename Functor > InterruptableEventPair makeInterruptableDelay( const Functor& rFunctor, + double nTimeout ) + { + InterruptableEventPair aRes; + + aRes.mpImmediateEvent = makeEvent( rFunctor, "makeInterruptableDelay"); + aRes.mpTimeoutEvent = std::make_shared<DelayFacade>( aRes.mpImmediateEvent, + nTimeout ); + + return aRes; + } + +} + +#endif // INCLUDED_SLIDESHOW_SOURCE_INC_INTERRUPTABLEDELAYEVENT_HXX + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |