From ab9dcfbd356bfa2e2054309ea0fdab31f9180497 Mon Sep 17 00:00:00 2001
From: Michael Mandl <mandlm@molez.net>
Date: Sun, 1 Nov 2015 12:36:23 +0100
Subject: [PATCH] Clean learner-thread termination on program exit

---
 gui/NeuroUI/netlearner.cpp | 9 ++++++++-
 gui/NeuroUI/netlearner.h   | 6 ++++++
 gui/NeuroUI/neuroui.cpp    | 6 ++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/gui/NeuroUI/netlearner.cpp b/gui/NeuroUI/netlearner.cpp
index b0956e1..3e7d5f9 100644
--- a/gui/NeuroUI/netlearner.cpp
+++ b/gui/NeuroUI/netlearner.cpp
@@ -24,7 +24,7 @@ void NetLearner::run()
         timer.start();
 
         size_t numIterations = 100000;
-        for (size_t iteration = 0; iteration < numIterations; ++iteration)
+        for (size_t iteration = 0; iteration < numIterations && cancel == false; ++iteration)
         {
             auto trainingSample = mnistLoader.getRandomSample();
 
@@ -76,4 +76,11 @@ void NetLearner::run()
         logString.append(ex.what());
         emit logMessage(logString);
     }
+
+    cancel = false;
+}
+
+void NetLearner::cancelLearning()
+{
+    cancel = true;
 }
diff --git a/gui/NeuroUI/netlearner.h b/gui/NeuroUI/netlearner.h
index 70378a4..018c3bf 100644
--- a/gui/NeuroUI/netlearner.h
+++ b/gui/NeuroUI/netlearner.h
@@ -7,6 +7,9 @@ class NetLearner : public QThread
 {
     Q_OBJECT
 
+private:
+    bool cancel = false;
+
 private:
     void run() Q_DECL_OVERRIDE;
 
@@ -15,6 +18,9 @@ signals:
     void progress(double progress);
     void currentNetError(double error);
     void sampleImageLoaded(const QImage &image);
+
+public slots:
+    void cancelLearning();
 };
 
 #endif // NETLEARNER_H
diff --git a/gui/NeuroUI/neuroui.cpp b/gui/NeuroUI/neuroui.cpp
index c057984..b366c65 100644
--- a/gui/NeuroUI/neuroui.cpp
+++ b/gui/NeuroUI/neuroui.cpp
@@ -12,6 +12,12 @@ NeuroUI::NeuroUI(QWidget *parent) :
 
 NeuroUI::~NeuroUI()
 {
+    if (m_netLearner != nullptr)
+    {
+        m_netLearner->cancelLearning();
+        m_netLearner->wait();
+    }
+
     delete ui;
 }