| 1 | /* $Id: EventQueue.h 69107 2017-10-17 10:53:48Z vboxsync $ */
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| 2 | /** @file
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| 3 | * MS COM / XPCOM Abstraction Layer - Event queue class declaration.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2013-2017 Oracle Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | */
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| 26 |
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| 27 | #ifndef ___VBox_com_EventQueue_h
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| 28 | #define ___VBox_com_EventQueue_h
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| 29 |
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| 30 | #include <list>
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| 31 |
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| 32 | #include <iprt/asm.h>
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| 33 | #include <iprt/critsect.h>
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| 34 |
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| 35 | #include <VBox/com/defs.h>
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| 36 | #include <VBox/com/assert.h>
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| 37 |
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| 38 |
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| 39 | /** @defgroup grp_com_evtqueue Event Queue Classes
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| 40 | * @ingroup grp_com
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| 41 | * @{
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| 42 | */
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| 43 |
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| 44 | namespace com
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| 45 | {
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| 46 |
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| 47 | class EventQueue;
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| 48 |
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| 49 | /**
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| 50 | * Base class for all events. Intended to be subclassed to introduce new
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| 51 | * events and handlers for them.
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| 52 | *
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| 53 | * Subclasses usually reimplement virtual #handler() (that does nothing by
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| 54 | * default) and add new data members describing the event.
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| 55 | */
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| 56 | class Event
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| 57 | {
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| 58 | public:
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| 59 |
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| 60 | Event(void) :
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| 61 | mRefCount(0) { }
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| 62 | virtual ~Event(void) { AssertMsg(!mRefCount,
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| 63 | ("Reference count of event=%p not 0 on destruction (is %RU32)\n",
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| 64 | this, mRefCount)); }
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| 65 | public:
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| 66 |
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| 67 | uint32_t AddRef(void) { return ASMAtomicIncU32(&mRefCount); }
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| 68 | void Release(void)
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| 69 | {
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| 70 | Assert(mRefCount);
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| 71 | uint32_t cRefs = ASMAtomicDecU32(&mRefCount);
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| 72 | if (!cRefs)
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| 73 | delete this;
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| 74 | }
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| 75 |
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| 76 | protected:
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| 77 |
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| 78 | /**
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| 79 | * Event handler. Called in the context of the event queue's thread.
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| 80 | * Always reimplemented by subclasses
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| 81 | *
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| 82 | * @return reserved, should be NULL.
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| 83 | */
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| 84 | virtual void *handler(void) { return NULL; }
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| 85 |
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| 86 | friend class EventQueue;
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| 87 |
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| 88 | protected:
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| 89 |
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| 90 | /** The event's reference count. */
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| 91 | uint32_t mRefCount;
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| 92 | };
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| 93 |
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| 94 | typedef std::list< Event* > EventQueueList;
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| 95 | typedef std::list< Event* >::iterator EventQueueListIterator;
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| 96 | typedef std::list< Event* >::const_iterator EventQueueListIteratorConst;
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| 97 |
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| 98 | /**
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| 99 | * Simple event queue.
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| 100 | */
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| 101 | class EventQueue
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| 102 | {
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| 103 | public:
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| 104 |
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| 105 | EventQueue(void);
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| 106 | virtual ~EventQueue(void);
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| 107 |
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| 108 | public:
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| 109 |
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| 110 | BOOL postEvent(Event *event);
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| 111 | int processEventQueue(RTMSINTERVAL cMsTimeout);
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| 112 | int processPendingEvents(size_t cNumEvents);
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| 113 | int interruptEventQueueProcessing();
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| 114 |
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| 115 | private:
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| 116 |
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| 117 | /** Critical section for serializing access to this
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| 118 | * event queue. */
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| 119 | RTCRITSECT mCritSect;
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| 120 | /** Number of concurrent users. At the moment we
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| 121 | * only support one concurrent user at a time when
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| 122 | calling processEventQueue(). */
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| 123 | uint32_t mUserCnt;
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| 124 | /** Event semaphore for getting notified on new
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| 125 | * events being handled. */
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| 126 | RTSEMEVENT mSemEvent;
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| 127 | /** The actual event queue, implemented as a list. */
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| 128 | EventQueueList mEvents;
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| 129 | /** Shutdown indicator. */
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| 130 | bool mShutdown;
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| 131 | };
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| 132 |
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| 133 | } /* namespace com */
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| 134 |
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| 135 | /** @} */
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| 136 |
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| 137 | #endif
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| 138 |
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