From 2a1541786ab963f73856b02600be379fd703c75e Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Sun, 16 Nov 2014 01:08:27 +0000
Subject: [PATCH] refs #334 Added class CContinuousWorker, base class for
 long-lived threaded worker objects. Inherits from CWorkerBase.

---
 src/blackmisc/worker.cpp | 39 ++++++++++++++++++++++++++++++++++++
 src/blackmisc/worker.h   | 43 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/src/blackmisc/worker.cpp b/src/blackmisc/worker.cpp
index ed29ea299..3f026a8f4 100644
--- a/src/blackmisc/worker.cpp
+++ b/src/blackmisc/worker.cpp
@@ -40,4 +40,43 @@ namespace BlackMisc
         QMetaObject::invokeMethod(this, "deleteLater");
     }
 
+    void CContinuousWorker::start(QThread::Priority priority)
+    {
+        if (m_name.isEmpty()) { m_name = metaObject()->className(); }
+
+        auto *thread = new CRegularThread(m_owner);
+
+        QString ownerName = m_owner->objectName().isEmpty() ? m_owner->metaObject()->className() : m_owner->objectName();
+        thread->setObjectName(ownerName + ":" + m_name);
+        setObjectName(m_name);
+
+        moveToThread(thread);
+        connect(thread, &QThread::started, this, &CContinuousWorker::initialize);
+        connect(thread, &QThread::finished, this, &CContinuousWorker::cleanup);
+        connect(thread, &QThread::finished, this, &CContinuousWorker::ps_finish);
+        thread->start(priority);
+    }
+
+    void CContinuousWorker::quit()
+    {
+        thread()->quit();
+    }
+
+    void CContinuousWorker::quitAndWait()
+    {
+        auto *ownThread = thread();
+        quit();
+        ownThread->wait();
+    }
+
+    void CContinuousWorker::ps_finish()
+    {
+        setFinished();
+
+        auto *ownThread = thread();
+        moveToThread(ownThread->thread()); // move worker back to the thread which constructed it, so there is no race on deletion
+        QMetaObject::invokeMethod(ownThread, "deleteLater");
+        QMetaObject::invokeMethod(this, "deleteLater");
+    }
+
 }
diff --git a/src/blackmisc/worker.h b/src/blackmisc/worker.h
index 6ec9180cc..7d594c6ce 100644
--- a/src/blackmisc/worker.h
+++ b/src/blackmisc/worker.h
@@ -210,6 +210,49 @@ namespace BlackMisc
         std::function<void()> m_task;
     };
 
+    /*!
+     * Base class for a long-lived worker object which lives in its own thread.
+     */
+    class CContinuousWorker : public CWorkerBase
+    {
+        Q_OBJECT
+
+    public:
+        /*!
+         * Constructor.
+         * \param owner Will be the parent of the new thread (the worker has no parent).
+         * \param name A name for the worker, which will be used to create a name for the thread.
+         */
+        CContinuousWorker(QObject *owner, const QString &name = "") : m_owner(owner), m_name(name) {}
+
+        //! Starts a thread and moves the worker into it.
+        void start(QThread::Priority priority = QThread::InheritPriority);
+
+        //! Stops the thread the next time around its event loop.
+        //! The thread and the worker will then be deleted.
+        //! \threadsafe
+        void quit();
+
+        //! Calls quit() and blocks until the thread is finished.
+        //! \threadsafe Will deadlock if called by the worker thread.
+        void quitAndWait();
+
+    protected slots:
+        //! Called when the thread is started.
+        virtual void initialize() {}
+
+        //! Called when the thread is finished.
+        virtual void cleanup() {}
+
+    private slots:
+        //! Called after cleanup().
+        void ps_finish();
+
+    private:
+        QObject *m_owner;
+        QString m_name;
+    };
+
 }
 
 #endif