| 1 | /* $Id: UIThreadPool.cpp 76606 2019-01-02 05:40:39Z vboxsync $ */
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| 2 | /** @file
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| 3 | * VBox Qt GUI - UIThreadPool and UITask classes implementation.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2013-2019 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 |
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| 18 | /* Qt includes: */
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| 19 | #include <QThread>
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| 20 |
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| 21 | /* GUI includes: */
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| 22 | #include "COMDefs.h"
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| 23 | #include "UIDefs.h"
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| 24 | #include "UIThreadPool.h"
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| 25 |
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| 26 | /* Other VBox includes: */
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| 27 | #include <iprt/assert.h>
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| 28 |
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| 29 |
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| 30 | /** QThread extension used as worker-thread.
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| 31 | * Capable of executing COM-related tasks. */
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| 32 | class UIThreadWorker : public QThread
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| 33 | {
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| 34 | Q_OBJECT;
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| 35 |
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| 36 | signals:
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| 37 |
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| 38 | /** Notifies listeners about @a pWorker finished. */
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| 39 | void sigFinished(UIThreadWorker *pWorker);
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| 40 |
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| 41 | public:
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| 42 |
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| 43 | /** Constructs worker-thread for parent worker-thread @a pPool.
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| 44 | * @param iIndex Brings worker-thread index within the worker-thread pool registry. */
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| 45 | UIThreadWorker(UIThreadPool *pPool, int iIndex);
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| 46 |
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| 47 | /** Returns worker-thread index within the worker-thread pool registry. */
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| 48 | int index() const { return m_iIndex; }
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| 49 |
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| 50 | /** Disables sigFinished signal, for optimizing worker-thread pool termination. */
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| 51 | void setNoFinishedSignal() { m_fNoFinishedSignal = true; }
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| 52 |
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| 53 | private:
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| 54 |
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| 55 | /** Contains the worker-thread body. */
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| 56 | void run();
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| 57 |
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| 58 | /** Holds the worker-thread pool reference. */
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| 59 | UIThreadPool *m_pPool;
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| 60 |
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| 61 | /** Holds the worker-thread index within the worker-thread pool registry. */
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| 62 | int m_iIndex;
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| 63 |
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| 64 | /** Holds whether sigFinished signal should be emitted or not. */
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| 65 | bool m_fNoFinishedSignal;
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| 66 | };
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| 67 |
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| 68 |
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| 69 | /*********************************************************************************************************************************
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| 70 | * Class UIThreadPool implementation. *
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| 71 | *********************************************************************************************************************************/
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| 72 |
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| 73 | UIThreadPool::UIThreadPool(ulong cMaxWorkers /* = 3 */, ulong cMsWorkerIdleTimeout /* = 5000 */)
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| 74 | : m_cMsIdleTimeout(cMsWorkerIdleTimeout)
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| 75 | , m_workers(cMaxWorkers)
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| 76 | , m_cWorkers(0)
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| 77 | , m_cIdleWorkers(0)
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| 78 | , m_fTerminating(false)
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| 79 | {
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| 80 | }
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| 81 |
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| 82 | UIThreadPool::~UIThreadPool()
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| 83 | {
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| 84 | /* Set termination status: */
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| 85 | setTerminating();
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| 86 |
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| 87 | /* Lock initially: */
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| 88 | m_everythingLocker.lock();
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| 89 |
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| 90 | /* Cleanup all the workers: */
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| 91 | for (int idxWorker = 0; idxWorker < m_workers.size(); ++idxWorker)
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| 92 | {
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| 93 | /* Acquire the worker: */
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| 94 | UIThreadWorker *pWorker = m_workers.at(idxWorker);
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| 95 | /* Remove it from the registry: */
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| 96 | m_workers[idxWorker] = 0;
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| 97 |
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| 98 | /* Clean up the worker, if there was one: */
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| 99 | if (pWorker)
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| 100 | {
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| 101 | /* Decrease the number of workers: */
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| 102 | --m_cWorkers;
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| 103 | /* Unlock temporary to let the worker finish: */
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| 104 | m_everythingLocker.unlock();
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| 105 | /* Wait for the worker to finish: */
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| 106 | pWorker->wait();
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| 107 | /* Lock again: */
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| 108 | m_everythingLocker.lock();
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| 109 | /* Delete the worker finally: */
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| 110 | delete pWorker;
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| 111 | }
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| 112 | }
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| 113 |
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| 114 | /* Cleanup all the tasks: */
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| 115 | qDeleteAll(m_pendingTasks);
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| 116 | qDeleteAll(m_executingTasks);
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| 117 | m_pendingTasks.clear();
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| 118 | m_executingTasks.clear();
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| 119 |
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| 120 | /* Unlock finally: */
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| 121 | m_everythingLocker.unlock();
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| 122 | }
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| 123 |
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| 124 | bool UIThreadPool::isTerminating() const
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| 125 | {
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| 126 | /* Lock initially: */
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| 127 | m_everythingLocker.lock();
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| 128 |
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| 129 | /* Acquire termination-flag: */
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| 130 | bool fTerminating = m_fTerminating;
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| 131 |
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| 132 | /* Unlock finally: */
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| 133 | m_everythingLocker.unlock();
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| 134 |
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| 135 | /* Return termination-flag: */
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| 136 | return fTerminating;
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| 137 | }
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| 138 |
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| 139 | void UIThreadPool::setTerminating()
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| 140 | {
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| 141 | /* Lock initially: */
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| 142 | m_everythingLocker.lock();
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| 143 |
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| 144 | /* Assign termination-flag: */
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| 145 | m_fTerminating = true;
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| 146 |
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| 147 | /* Tell all threads to NOT queue any termination signals: */
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| 148 | for (int idxWorker = 0; idxWorker < m_workers.size(); ++idxWorker)
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| 149 | {
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| 150 | UIThreadWorker *pWorker = m_workers.at(idxWorker);
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| 151 | if (pWorker)
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| 152 | pWorker->setNoFinishedSignal();
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| 153 | }
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| 154 |
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| 155 | /* Wake up all idle worker threads: */
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| 156 | m_taskCondition.wakeAll();
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| 157 |
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| 158 | /* Unlock finally: */
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| 159 | m_everythingLocker.unlock();
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| 160 | }
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| 161 |
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| 162 | void UIThreadPool::enqueueTask(UITask *pTask)
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| 163 | {
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| 164 | /* Do nothing if terminating: */
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| 165 | AssertReturnVoid(!isTerminating());
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| 166 |
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| 167 | /* Prepare task: */
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| 168 | connect(pTask, &UITask::sigComplete,
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| 169 | this, &UIThreadPool::sltHandleTaskComplete, Qt::QueuedConnection);
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| 170 |
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| 171 | /* Lock initially: */
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| 172 | m_everythingLocker.lock();
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| 173 |
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| 174 | /* Put the task into the queue: */
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| 175 | m_pendingTasks.enqueue(pTask);
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| 176 |
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| 177 | /* Wake up an idle worker if we got one: */
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| 178 | if (m_cIdleWorkers > 0)
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| 179 | {
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| 180 | m_taskCondition.wakeOne();
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| 181 | }
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| 182 | /* No idle worker threads, should we create a new one? */
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| 183 | else if (m_cWorkers < m_workers.size())
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| 184 | {
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| 185 | /* Find free slot: */
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| 186 | int idxFirstUnused = m_workers.size();
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| 187 | while (idxFirstUnused-- > 0)
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| 188 | if (m_workers.at(idxFirstUnused) == 0)
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| 189 | {
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| 190 | /* Prepare the new worker: */
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| 191 | UIThreadWorker *pWorker = new UIThreadWorker(this, idxFirstUnused);
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| 192 | connect(pWorker, &UIThreadWorker::sigFinished,
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| 193 | this, &UIThreadPool::sltHandleWorkerFinished, Qt::QueuedConnection);
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| 194 | m_workers[idxFirstUnused] = pWorker;
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| 195 | ++m_cWorkers;
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| 196 |
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| 197 | /* And start it: */
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| 198 | pWorker->start();
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| 199 | break;
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| 200 | }
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| 201 | }
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| 202 | /* else: wait for some worker to complete
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| 203 | * whatever it's busy with and jump to it. */
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| 204 |
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| 205 | /* Unlock finally: */
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| 206 | m_everythingLocker.unlock();
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| 207 | }
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| 208 |
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| 209 | UITask *UIThreadPool::dequeueTask(UIThreadWorker *pWorker)
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| 210 | {
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| 211 | /* Lock initially: */
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| 212 | m_everythingLocker.lock();
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| 213 |
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| 214 | /* Dequeue a task, watching out for terminations.
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| 215 | * For optimal efficiency in enqueueTask() we keep count of idle threads.
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| 216 | * If the wait times out, we'll return 0 and terminate the thread. */
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| 217 | bool fIdleTimedOut = false;
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| 218 | while (!m_fTerminating)
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| 219 | {
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| 220 | /* Make sure that worker has proper index: */
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| 221 | Assert(m_workers.at(pWorker->index()) == pWorker);
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| 222 |
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| 223 | /* Dequeue task if there is one: */
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| 224 | if (!m_pendingTasks.isEmpty())
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| 225 | {
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| 226 | UITask *pTask = m_pendingTasks.dequeue();
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| 227 | if (pTask)
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| 228 | {
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| 229 | /* Put into the set of executing tasks: */
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| 230 | m_executingTasks << pTask;
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| 231 |
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| 232 | /* Unlock finally: */
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| 233 | m_everythingLocker.unlock();
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| 234 |
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| 235 | /* Return dequeued task: */
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| 236 | return pTask;
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| 237 | }
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| 238 | }
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| 239 |
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| 240 | /* If we timed out already, then quit the worker thread. To prevent a
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| 241 | * race between enqueueTask and the queue removal of the thread from
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| 242 | * the workers vector, we remove it here already. (This does not apply
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| 243 | * to the termination scenario.) */
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| 244 | if (fIdleTimedOut)
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| 245 | {
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| 246 | m_workers[pWorker->index()] = 0;
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| 247 | --m_cWorkers;
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| 248 | break;
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| 249 | }
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| 250 |
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| 251 | /* Wait for a task or timeout: */
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| 252 | ++m_cIdleWorkers;
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| 253 | fIdleTimedOut = !m_taskCondition.wait(&m_everythingLocker, m_cMsIdleTimeout);
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| 254 | --m_cIdleWorkers;
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| 255 | }
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| 256 |
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| 257 | /* Unlock finally: */
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| 258 | m_everythingLocker.unlock();
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| 259 |
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| 260 | /* Return 0 by default: */
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| 261 | return 0;
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| 262 | }
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| 263 |
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| 264 | void UIThreadPool::sltHandleTaskComplete(UITask *pTask)
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| 265 | {
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| 266 | /* Skip on termination: */
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| 267 | if (isTerminating())
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| 268 | return;
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| 269 |
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| 270 | /* Notify listeners: */
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| 271 | emit sigTaskComplete(pTask);
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| 272 |
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| 273 | /* Lock initially: */
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| 274 | m_everythingLocker.lock();
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| 275 |
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| 276 | /* Delete task finally: */
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| 277 | if ( !m_executingTasks.contains(pTask)
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| 278 | || !m_executingTasks.remove(pTask))
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| 279 | AssertMsgFailed(("Unable to find or remove complete task!"));
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| 280 | delete pTask;
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| 281 |
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| 282 | /* Unlock finally: */
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| 283 | m_everythingLocker.unlock();
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| 284 | }
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| 285 |
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| 286 | void UIThreadPool::sltHandleWorkerFinished(UIThreadWorker *pWorker)
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| 287 | {
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| 288 | /* Wait for the thread to finish completely, then delete the thread
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| 289 | * object. We have already removed the thread from the workers vector.
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| 290 | * Note! We don't want to use 'this' here, in case it's invalid. */
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| 291 | pWorker->wait();
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| 292 | delete pWorker;
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| 293 | }
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| 294 |
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| 295 | void UITask::start()
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| 296 | {
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| 297 | /* Run task: */
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| 298 | run();
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| 299 | /* Notify listeners: */
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| 300 | emit sigComplete(this);
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| 301 | }
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| 302 |
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| 303 |
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| 304 | /*********************************************************************************************************************************
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| 305 | * Class UIThreadWorker implementation. *
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| 306 | *********************************************************************************************************************************/
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| 307 |
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| 308 | UIThreadWorker::UIThreadWorker(UIThreadPool *pPool, int iIndex)
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| 309 | : m_pPool(pPool)
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| 310 | , m_iIndex(iIndex)
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| 311 | , m_fNoFinishedSignal(false)
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| 312 | {
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| 313 | }
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| 314 |
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| 315 | void UIThreadWorker::run()
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| 316 | {
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| 317 | /* Initialize COM: */
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| 318 | COMBase::InitializeCOM(false);
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| 319 |
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| 320 | /* Try get a task from the pool queue: */
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| 321 | while (UITask *pTask = m_pPool->dequeueTask(this))
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| 322 | {
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| 323 | /* Process the task if we are not terminating.
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| 324 | * Please take into account tasks are cleared by the UIThreadPool
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| 325 | * after all listeners notified about task is complete and handled it. */
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| 326 | if (!m_pPool->isTerminating())
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| 327 | pTask->start();
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| 328 | }
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| 329 |
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| 330 | /* Cleanup COM: */
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| 331 | COMBase::CleanupCOM();
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| 332 |
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| 333 | /* Queue a signal for the pool to do thread cleanup, unless the pool is
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| 334 | already terminating and doesn't need the signal. */
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| 335 | if (!m_fNoFinishedSignal)
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| 336 | emit sigFinished(this);
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| 337 | }
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| 338 |
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| 339 |
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| 340 | #include "UIThreadPool.moc"
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| 341 |
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