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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
commited5640d8b587fbcfed7dd7967f3de04b37a76f26 (patch)
tree7a5f7c6c9d02226d7471cb3cc8fbbf631b415303 /include/comphelper/asyncnotification.hxx
parentInitial commit. (diff)
downloadlibreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.tar.xz
libreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.zip
Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* -*- 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_COMPHELPER_ASYNCNOTIFICATION_HXX
+#define INCLUDED_COMPHELPER_ASYNCNOTIFICATION_HXX
+
+#include <sal/config.h>
+
+#include <comphelper/comphelperdllapi.h>
+#include <rtl/ref.hxx>
+#include <sal/types.h>
+#include <salhelper/thread.hxx>
+#include <salhelper/simplereferenceobject.hxx>
+#include <memory>
+#include <utility>
+
+namespace comphelper
+{
+ //= AnyEvent
+
+ /** the very basic instance to hold a description of an event
+ */
+ class COMPHELPER_DLLPUBLIC AnyEvent : public salhelper::SimpleReferenceObject
+ {
+ public:
+ AnyEvent();
+
+ protected:
+ virtual ~AnyEvent() override;
+
+ private:
+ AnyEvent( AnyEvent const & ) = delete;
+ AnyEvent& operator=( AnyEvent const & ) = delete;
+ };
+
+
+ //= typedefs
+
+ typedef ::rtl::Reference< AnyEvent > AnyEventRef;
+
+
+ //= IEventProcessor
+
+ /** an event processor
+
+ @see AsyncEventNotifier
+ */
+ class SAL_NO_VTABLE IEventProcessor
+ {
+ public:
+ /** process a single event
+ */
+ virtual void processEvent( const AnyEvent& _rEvent ) = 0;
+
+ virtual void SAL_CALL acquire() noexcept = 0;
+ virtual void SAL_CALL release() noexcept = 0;
+
+ protected:
+ ~IEventProcessor() {}
+ };
+
+
+ //= AsyncEventNotifier
+
+ struct EventNotifierImpl;
+
+ /** a helper class for notifying events asynchronously
+
+ If you need to notify certain events to external components, you usually should
+ not do this while you have mutexes locked, to prevent multi-threading issues.
+
+ However, you do not always have complete control over all mutex guards on the stack.
+ If, in such a case, the listener notification is one-way, you can decide to do it
+ asynchronously.
+
+ The ->AsyncEventNotifier helps you to process such events asynchronously. Every
+ event is tied to an ->IEventProcessor which is responsible for processing it.
+
+ The AsyncEventNotifier is implemented as a thread itself, which sleeps as long as there are no
+ events in the queue. As soon as you add an event, the thread is woken up, processes the event,
+ and sleeps again.
+ */
+ class COMPHELPER_DLLPUBLIC AsyncEventNotifierBase
+ {
+ friend struct EventNotifierImpl;
+
+ protected:
+ std::unique_ptr<EventNotifierImpl> m_xImpl;
+
+ SAL_DLLPRIVATE virtual ~AsyncEventNotifierBase();
+
+ // Thread
+ SAL_DLLPRIVATE virtual void execute();
+
+ public:
+ AsyncEventNotifierBase();
+
+ /** terminates the thread
+
+ Note that this is a cooperative termination - if you call this from a thread different
+ from the notification thread itself, then it will block until the notification thread
+ finished processing the current event. If you call it from the notification thread
+ itself, it will return immediately, and the thread will be terminated as soon as
+ the current notification is finished.
+ */
+ virtual void SAL_CALL terminate();
+
+ /** adds an event to the queue, together with the instance which is responsible for
+ processing it
+
+ @param _rEvent
+ the event to add to the queue
+ @param _xProcessor
+ the processor for the event.<br/>
+ Beware of life time issues here. If your event processor dies or becomes otherwise
+ nonfunctional, you are responsible for removing all respective events from the queue.
+ You can do this by calling ->removeEventsForProcessor
+ */
+ void addEvent( const AnyEventRef& _rEvent, const ::rtl::Reference< IEventProcessor >& _xProcessor );
+
+ /** removes all events for the given event processor from the queue
+ */
+ void removeEventsForProcessor( const ::rtl::Reference< IEventProcessor >& _xProcessor );
+ };
+
+ /** This class is usable with rtl::Reference.
+ As always, the thread must be joined somewhere.
+ */
+ class COMPHELPER_DLLPUBLIC AsyncEventNotifier final
+ : public AsyncEventNotifierBase
+ , public salhelper::Thread
+ {
+
+ private:
+ SAL_DLLPRIVATE virtual ~AsyncEventNotifier() override;
+
+ SAL_DLLPRIVATE virtual void execute() override;
+
+ public:
+ /** constructs a notifier thread
+
+ @param name the thread name, see ::osl_setThreadName; must not be
+ null
+ */
+ AsyncEventNotifier(char const* name);
+
+ virtual void SAL_CALL terminate() override;
+ };
+
+ /** This is a hack (when proper joining is not possible), use of which
+ should be avoided by good design.
+ */
+ class COMPHELPER_DLLPUBLIC AsyncEventNotifierAutoJoin final
+ : public AsyncEventNotifierBase
+ , private osl::Thread
+ {
+
+ private:
+ SAL_DLLPRIVATE AsyncEventNotifierAutoJoin(char const* name);
+
+ SAL_DLLPRIVATE virtual void SAL_CALL run() override;
+ SAL_DLLPRIVATE virtual void SAL_CALL onTerminated() override;
+
+ public:
+ // only public so shared_ptr finds it
+ SAL_DLLPRIVATE virtual ~AsyncEventNotifierAutoJoin() override;
+
+ static std::shared_ptr<AsyncEventNotifierAutoJoin>
+ newAsyncEventNotifierAutoJoin(char const* name);
+
+ virtual void SAL_CALL terminate() override;
+
+ using osl::Thread::join;
+ using osl::Thread::operator new;
+ using osl::Thread::operator delete; // clang really wants this?
+
+ static void launch(std::shared_ptr<AsyncEventNotifierAutoJoin> const&);
+ };
+
+
+ //= EventHolder
+
+ /** AnyEvent derivee holding a foreign event instance
+ */
+ template < typename EVENT_OBJECT >
+ class SAL_DLLPUBLIC_RTTI EventHolder final : public AnyEvent
+ {
+ public:
+ typedef EVENT_OBJECT EventObjectType;
+
+ private:
+ EventObjectType const m_aEvent;
+
+ public:
+ EventHolder( EventObjectType _aEvent )
+ :m_aEvent(std::move( _aEvent ))
+ {
+ }
+
+ const EventObjectType& getEventObject() const { return m_aEvent; }
+ };
+
+ COMPHELPER_DLLPUBLIC void JoinAsyncEventNotifiers();
+
+} // namespace comphelper
+
+
+#endif // INCLUDED_COMPHELPER_ASYNCNOTIFICATION_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */