Added MessagePipes garbage collector. Updated versions and changelogsv6.3.1sdrangel-v$(appveyor_build_version)

16 files changed, 403 insertions, 45 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 8cf23208c..1d7adb401 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,12 @@
+sdrangel (6.3.1-1) unstable; urgency=medium
+
+   * Implemented garbage collector for message pipes. Applies to VORLocalizer.
+   * FreeDV: removed useless set callback functions. Use mutex appropriately. Issue #728
+   * ATV demod: initialize m_tvScreenBuffer when setting m_registeredTVScreen. Issue #728
+   * TVScreenAnalog: removed usage of std::shared_ptr. Issue #728
+
+  -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Sat, 12 Dec 2020 14:45:22 +0100
+
 sdrangel (6.3.0-1) unstable; urgency=medium
 
    * Single channel VOR demodulator plugin. Issue #729
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bccaf8d83..8447a943c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 # configure version
 set(sdrangel_VERSION_MAJOR "6")
 set(sdrangel_VERSION_MINOR "3")
-set(sdrangel_VERSION_PATCH "0")
+set(sdrangel_VERSION_PATCH "1")
 set(sdrangel_VERSION_SUFFIX "")
 
 # SDRAngel cmake options
diff --git a/debian/changelog b/debian/changelog
index 33eecbd2f..e276faae1 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,12 @@
+sdrangel (6.3.1-1) unstable; urgency=medium
+
+   * Implemented garbage collector for message pipes. Applies to VORLocalizer.
+   * FreeDV: removed useless set callback functions. Use mutex appropriately. Issue #728
+   * ATV demod: initialize m_tvScreenBuffer when setting m_registeredTVScreen. Issue #728
+   * TVScreenAnalog: removed usage of std::shared_ptr. Issue #728
+
+  -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Sat, 12 Dec 2020 14:45:22 +0100
+
 sdrangel (6.3.0-1) unstable; urgency=medium
 
    * Single channel VOR demodulator plugin. Issue #729
diff --git a/plugins/channelrx/demodatv/atvdemodplugin.cpp b/plugins/channelrx/demodatv/atvdemodplugin.cpp
index bfcc9e7f7..7959151b1 100644
--- a/plugins/channelrx/demodatv/atvdemodplugin.cpp
+++ b/plugins/channelrx/demodatv/atvdemodplugin.cpp
@@ -30,7 +30,7 @@ const PluginDescriptor ATVDemodPlugin::m_ptrPluginDescriptor =
 {
     ATVDemod::m_channelId,
 	QString("ATV Demodulator"),
-	QString("4.19.0"),
+	QString("6.3.1"),
     QString("(c) F4HKW for F4EXB / SDRAngel"),
 	QString("https://github.com/f4exb/sdrangel"),
 	true,
diff --git a/plugins/channelrx/demodfreedv/freedvplugin.cpp b/plugins/channelrx/demodfreedv/freedvplugin.cpp
index 8bfe18280..6a3bfe4c7 100644
--- a/plugins/channelrx/demodfreedv/freedvplugin.cpp
+++ b/plugins/channelrx/demodfreedv/freedvplugin.cpp
@@ -28,7 +28,7 @@
 const PluginDescriptor FreeDVPlugin::m_pluginDescriptor = {
     FreeDVDemod::m_channelId,
 	QStringLiteral("FreeDV Demodulator"),
-	QStringLiteral("4.19.0"),
+	QStringLiteral("6.3.1"),
 	QStringLiteral("(c) Edouard Griffiths, F4EXB"),
 	QStringLiteral("https://github.com/f4exb/sdrangel"),
 	true,
diff --git a/plugins/channeltx/modfreedv/freedvmodplugin.cpp b/plugins/channeltx/modfreedv/freedvmodplugin.cpp
index 91da2ba32..9a3e0cf1f 100644
--- a/plugins/channeltx/modfreedv/freedvmodplugin.cpp
+++ b/plugins/channeltx/modfreedv/freedvmodplugin.cpp
@@ -28,7 +28,7 @@
 const PluginDescriptor FreeDVModPlugin::m_pluginDescriptor = {
     FreeDVMod::m_channelId,
     QStringLiteral("FreeDV Modulator"),
-    QStringLiteral("6.1.0"),
+    QStringLiteral("6.3.1"),
     QStringLiteral("(c) Edouard Griffiths, F4EXB"),
     QStringLiteral("https://github.com/f4exb/sdrangel"),
     true,
diff --git a/plugins/feature/vorlocalizer/vorlocalizer.cpp b/plugins/feature/vorlocalizer/vorlocalizer.cpp
index 5d0f37f5c..90ce38fcc 100644
--- a/plugins/feature/vorlocalizer/vorlocalizer.cpp
+++ b/plugins/feature/vorlocalizer/vorlocalizer.cpp
@@ -218,7 +218,7 @@ bool VORLocalizer::handleMessage(const Message& cmd)
     }
     else if (VORLocalizerReport::MsgReportServiceddVORs::match(cmd))
     {
-        qDebug() << "VORLocalizer::handleMessage: MsgReportServiceddVORs:";
+        qDebug() << "VORLocalizer::handleMessage: MsgReportServiceddVORs";
         VORLocalizerReport::MsgReportServiceddVORs& report = (VORLocalizerReport::MsgReportServiceddVORs&) cmd;
         std::vector<int>& vorNavIds = report.getNavIds();
         m_vorSinglePlans = report.getSinglePlans();
@@ -239,6 +239,18 @@ bool VORLocalizer::handleMessage(const Message& cmd)
 
         return true;
     }
+    else if (MessagePipesCommon::MsgReportChannelDeleted::match(cmd))
+    {
+        qDebug() << "VORLocalizer::handleMessage: MsgReportChannelDeleted";
+        MessagePipesCommon::MsgReportChannelDeleted& report = (MessagePipesCommon::MsgReportChannelDeleted&) cmd;
+        const MessagePipesCommon::ChannelRegistrationKey& channelKey = report.getChannelRegistrationKey();
+        const ChannelAPI *channel = channelKey.m_channel;
+        m_availableChannels.remove(const_cast<ChannelAPI*>(channel));
+        updateChannels();
+        MainCore::instance()->getMessagePipes().unregisterChannelToFeature(channel, this, "report");
+
+        return true;
+    }
     else
 	{
 		return false;
@@ -366,6 +378,7 @@ void VORLocalizer::updateChannels()
     {
         VORLocalizerReport::MsgReportChannels *msgToGUI = VORLocalizerReport::MsgReportChannels::create();
         std::vector<VORLocalizerReport::MsgReportChannels::Channel>& msgChannels = msgToGUI->getChannels();
+        // TODO: check https://github.com/microsoft/vscode-cpptools/issues/6222
         QHash<ChannelAPI*, VORLocalizerSettings::AvailableChannel>::iterator it = m_availableChannels.begin();
 
         for (; it != m_availableChannels.end(); ++it)
diff --git a/plugins/feature/vorlocalizer/vorlocalizerplugin.cpp b/plugins/feature/vorlocalizer/vorlocalizerplugin.cpp
index b1e9e1971..0761fc85c 100644
--- a/plugins/feature/vorlocalizer/vorlocalizerplugin.cpp
+++ b/plugins/feature/vorlocalizer/vorlocalizerplugin.cpp
@@ -29,7 +29,7 @@
 const PluginDescriptor VORLocalizerPlugin::m_pluginDescriptor = {
     VORLocalizer::m_featureId,
 	QStringLiteral("VOR Localizer"),
-	QStringLiteral("6.3.0"),
+	QStringLiteral("6.3.1"),
 	QStringLiteral("(c) Jon Beniston, M7RCE"),
 	QStringLiteral("https://github.com/f4exb/sdrangel"),
 	true,
diff --git a/sdrbase/CMakeLists.txt b/sdrbase/CMakeLists.txt
index f14df3460..82465b34f 100644
--- a/sdrbase/CMakeLists.txt
+++ b/sdrbase/CMakeLists.txt
@@ -161,6 +161,8 @@ set(sdrbase_SOURCES
     limerfe/limerfeusbcalib.cpp
 
     pipes/messagepipes.cpp
+    pipes/messagepipescommon.cpp
+    pipes/messagepipesgcworker.cpp
 
     settings/featuresetpreset.cpp
     settings/preferences.cpp
@@ -335,6 +337,8 @@ set(sdrbase_HEADERS
     limerfe/limerfeusbcalib.h
 
     pipes/messagepipes.h
+    pipes/messagepipescommon.h
+    pipes/messagepipesgcworker.h
 
     plugin/plugininterface.h
     plugin/pluginapi.h
diff --git a/sdrbase/maincore.h b/sdrbase/maincore.h
index dd73d498f..a121ead23 100644
--- a/sdrbase/maincore.h
+++ b/sdrbase/maincore.h
@@ -449,8 +449,8 @@ public:
     void setLoggingOptions();
     ChannelAPI *getChannel(unsigned int deviceSetIndex, int channelIndex);
     Feature *getFeature(unsigned int featureSetIndex, int featureIndex);
-    bool existsChannel(ChannelAPI *channel) const { return m_channelsMap.contains(channel); }
-    bool existsFeature(Feature *feature) const { return m_featuresMap.contains(feature); }
+    bool existsChannel(const ChannelAPI *channel) const { return m_channelsMap.contains(const_cast<ChannelAPI*>(channel)); }
+    bool existsFeature(const Feature *feature) const { return m_featuresMap.contains(const_cast<Feature*>(feature)); }
     // slave mode
     void appendFeatureSet();
     void removeFeatureSet(unsigned int index);
diff --git a/sdrbase/pipes/messagepipes.cpp b/sdrbase/pipes/messagepipes.cpp
index 3aaae269b..139e1e6df 100644
--- a/sdrbase/pipes/messagepipes.cpp
+++ b/sdrbase/pipes/messagepipes.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////////
-// Copyright (C) 2015 Edouard Griffiths, F4EXB                                   //
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
 //                                                                               //
 // This program is free software; you can redistribute it and/or modify          //
 // it under the terms of the GNU General Public License as published by          //
@@ -17,26 +17,28 @@
 
 #include <QGlobalStatic>
 
+#include "messagepipesgcworker.h"
 #include "messagepipes.h"
 
-bool MessagePipes::ChannelRegistrationKey::operator<(const ChannelRegistrationKey& other) const
+MessagePipes::MessagePipes() :
+	m_typeCount(0),
+	m_c2fMutex(QMutex::Recursive)
 {
-	if (m_channel !=  other.m_channel) {
-		return m_channel < other.m_channel;
-	} else {
-		return m_typeId < other.m_typeId;
-	}
+	m_gcWorker = new MessagePipesGCWorker();
+	m_gcWorker->setC2FRegistrations(&m_c2fMutex, &m_c2fQueues, &m_c2fFEatures);
+	m_gcWorker->moveToThread(&m_gcThread);
+	startGC();
 }
 
-MessagePipes::MessagePipes() :
-	m_typeCount(0)
-{}
-
 MessagePipes::~MessagePipes()
 {
-	QMap<ChannelRegistrationKey, QList<MessageQueue*>>::iterator mit = m_messageRegistrations.begin();
+	if (m_gcWorker->isRunning()) {
+		stopGC();
+	}
+
+	QMap<MessagePipesCommon::ChannelRegistrationKey, QList<MessageQueue*>>::iterator mit = m_c2fQueues.begin();
 
-	for (; mit != m_messageRegistrations.end(); ++mit)
+	for (; mit != m_c2fQueues.end(); ++mit)
 	{
 		QList<MessageQueue*>::iterator lit = mit->begin();
 
@@ -46,9 +48,10 @@ MessagePipes::~MessagePipes()
 	}
 }
 
-MessageQueue *MessagePipes::registerChannelToFeature(const ChannelAPI *source, const Feature *feature, const QString& type)
+MessageQueue *MessagePipes::registerChannelToFeature(const ChannelAPI *source, Feature *feature, const QString& type)
 {
 	int typeId;
+	QMutexLocker mlock(&m_c2fMutex);
 
 	if (m_typeIds.contains(type))
 	{
@@ -60,32 +63,71 @@ MessageQueue *MessagePipes::registerChannelToFeature(const ChannelAPI *source, c
 		m_typeIds.insert(type, typeId);
 	}
 
-	const ChannelRegistrationKey regKey = ChannelRegistrationKey{source, typeId};
+	const MessagePipesCommon::ChannelRegistrationKey regKey = MessagePipesCommon::ChannelRegistrationKey{source, typeId};
+	MessageQueue *messageQueue;
 
-	if (m_messageRegistrations.contains(regKey))
+	if (m_c2fFEatures[regKey].contains(feature))
 	{
-		m_messageRegistrations.insert(regKey, QList<MessageQueue*>());
-		m_featureRegistrations.insert(regKey, QList<const Feature*>());
+		int i = m_c2fFEatures[regKey].indexOf(feature);
+		messageQueue = m_c2fQueues[regKey][i];
+	}
+	else
+	{
+		messageQueue = new MessageQueue();
+		m_c2fQueues[regKey].append(messageQueue);
+		m_c2fFEatures[regKey].append(feature);
 	}
-
-	MessageQueue *messageQueue = new MessageQueue();
-	m_messageRegistrations[regKey].append(messageQueue);
-	m_featureRegistrations[regKey].append(feature);
 
 	return messageQueue;
 }
 
+void MessagePipes::unregisterChannelToFeature(const ChannelAPI *source, Feature *feature, const QString& type)
+{
+	if (m_typeIds.contains(type))
+	{
+		int typeId = m_typeIds.value(type);
+		const MessagePipesCommon::ChannelRegistrationKey regKey = MessagePipesCommon::ChannelRegistrationKey{source, typeId};
+
+		if (m_c2fFEatures.contains(regKey) && m_c2fFEatures[regKey].contains(feature))
+		{
+			QMutexLocker mlock(&m_c2fMutex);
+			int i = m_c2fFEatures[regKey].indexOf(feature);
+			m_c2fFEatures[regKey].removeAt(i);
+			MessageQueue *messageQueue = m_c2fQueues[regKey][i];
+			delete messageQueue;
+			m_c2fQueues[regKey].removeAt(i);
+		}
+	}
+}
+
 QList<MessageQueue*>* MessagePipes::getMessageQueues(const ChannelAPI *source, const QString& type)
 {
 	if (!m_typeIds.contains(type)) {
 		return nullptr;
 	}
 
-	const ChannelRegistrationKey regKey = ChannelRegistrationKey{source, m_typeIds.value(type)};
+	QMutexLocker mlock(&m_c2fMutex);
+	const MessagePipesCommon::ChannelRegistrationKey regKey = MessagePipesCommon::ChannelRegistrationKey{source, m_typeIds.value(type)};
 
-	if (m_messageRegistrations.contains(regKey)) {
-		return &m_messageRegistrations[regKey];
+	if (m_c2fQueues.contains(regKey)) {
+		return &m_c2fQueues[regKey];
 	} else {
 		return nullptr;
 	}
 }
+
+void MessagePipes::startGC()
+{
+	qDebug("MessagePipes::startGC");
+
+    m_gcWorker->startWork();
+    m_gcThread.start();
+}
+
+void MessagePipes::stopGC()
+{
+    qDebug("MessagePipes::stopGC");
+	m_gcWorker->stopWork();
+	m_gcThread.quit();
+	m_gcThread.wait();
+}
diff --git a/sdrbase/pipes/messagepipes.h b/sdrbase/pipes/messagepipes.h
index 0f97b75fc..8145e1252 100644
--- a/sdrbase/pipes/messagepipes.h
+++ b/sdrbase/pipes/messagepipes.h
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////////
-// Copyright (C) 2015 Edouard Griffiths, F4EXB                                   //
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
 //                                                                               //
 // This program is free software; you can redistribute it and/or modify          //
 // it under the terms of the GNU General Public License as published by          //
@@ -21,38 +21,42 @@
 #include <QObject>
 #include <QHash>
 #include <QMap>
+#include <QMutex>
+#include <QThread>
 
 #include "export.h"
 #include "util/messagequeue.h"
 
+#include "messagepipescommon.h"
+
 class ChannelAPI;
 class Feature;
+class MessagePipesGCWorker;
 
 class SDRBASE_API MessagePipes : public QObject
 {
     Q_OBJECT
 public:
-    struct ChannelRegistrationKey
-    {
-        const ChannelAPI *m_channel;
-        int m_typeId;
-
-        bool operator<(const ChannelRegistrationKey& other) const;
-    };
-
     MessagePipes();
     MessagePipes(const MessagePipes&) = delete;
     MessagePipes& operator=(const MessagePipes&) = delete;
     ~MessagePipes();
 
-    MessageQueue *registerChannelToFeature(const ChannelAPI *source, const Feature *feature, const QString& type);
+    MessageQueue *registerChannelToFeature(const ChannelAPI *source, Feature *feature, const QString& type);
+    void unregisterChannelToFeature(const ChannelAPI *source, Feature *feature, const QString& type);
     QList<MessageQueue*>* getMessageQueues(const ChannelAPI *source, const QString& type);
 
 private:
     QHash<QString, int> m_typeIds;
     int m_typeCount;
-    QMap<ChannelRegistrationKey, QList<MessageQueue*>> m_messageRegistrations;
-    QMap<ChannelRegistrationKey, QList<const Feature*>> m_featureRegistrations;
+    QMap<MessagePipesCommon::ChannelRegistrationKey, QList<MessageQueue*>> m_c2fQueues;
+    QMap<MessagePipesCommon::ChannelRegistrationKey, QList<Feature*>> m_c2fFEatures;
+    QMutex m_c2fMutex;
+    QThread m_gcThread; //!< Garbage collector thread
+    MessagePipesGCWorker *m_gcWorker; //!< Garbage collector
+
+	void startGC(); //!< Start garbage collector
+	void stopGC();  //!< Stop garbage collector
 };
 
 #endif // SDRBASE_PIPES_MESSAGEPIPES_H_
diff --git a/sdrbase/pipes/messagepipescommon.cpp b/sdrbase/pipes/messagepipescommon.cpp
new file mode 100644
index 000000000..1244d1a10
--- /dev/null
+++ b/sdrbase/pipes/messagepipescommon.cpp
@@ -0,0 +1,29 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+// (at your option) any later version.                                           //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#include "messagepipescommon.h"
+
+MESSAGE_CLASS_DEFINITION(MessagePipesCommon::MsgReportChannelDeleted, Message)
+
+bool MessagePipesCommon::ChannelRegistrationKey::operator<(const ChannelRegistrationKey& other) const
+{
+	if (m_channel !=  other.m_channel) {
+		return m_channel < other.m_channel;
+	} else {
+		return m_typeId < other.m_typeId;
+	}
+}
diff --git a/sdrbase/pipes/messagepipescommon.h b/sdrbase/pipes/messagepipescommon.h
new file mode 100644
index 000000000..e4467b5c7
--- /dev/null
+++ b/sdrbase/pipes/messagepipescommon.h
@@ -0,0 +1,70 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+// (at your option) any later version.                                           //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef SDRBASE_PIPES_MESSAGEPIPESCOMON_H_
+#define SDRBASE_PIPES_MESSAGEPIPESCOMON_H_
+
+#include <QHash>
+#include <QMap>
+#include <QMutex>
+
+#include "export.h"
+#include "util/message.h"
+
+class ChannelAPI;
+class Feature;
+class MessageQueue;
+
+class SDRBASE_API MessagePipesCommon
+{
+public:
+    struct ChannelRegistrationKey
+    {
+        const ChannelAPI *m_channel;
+        int m_typeId;
+
+        ChannelRegistrationKey() = default;
+        ChannelRegistrationKey(const ChannelRegistrationKey&) = default;
+        ChannelRegistrationKey& operator=(const ChannelRegistrationKey&) = default;
+        bool operator<(const ChannelRegistrationKey& other) const;
+    };
+
+    /** Send this message to stakeholders when the garbage collector finds that a channel was deleted */
+    class MsgReportChannelDeleted : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        const MessageQueue *getMessageQueue() const { return m_messageQueue; }
+        const ChannelRegistrationKey& getChannelRegistrationKey() const { return m_channelRegistrationKey; }
+
+        static MsgReportChannelDeleted* create(const MessageQueue *messageQueue, const ChannelRegistrationKey& channelRegistrationKey) {
+            return new MsgReportChannelDeleted(messageQueue, channelRegistrationKey);
+        }
+
+    private:
+        const MessageQueue *m_messageQueue;
+        ChannelRegistrationKey m_channelRegistrationKey;
+
+        MsgReportChannelDeleted(const MessageQueue *messageQueue, const ChannelRegistrationKey& channelRegistrationKey) :
+            Message(),
+            m_messageQueue(messageQueue),
+            m_channelRegistrationKey(channelRegistrationKey)
+        { }
+    };
+};
+
+#endif // SDRBASE_PIPES_MESSAGEPIPESCOMON_H_
diff --git a/sdrbase/pipes/messagepipesgcworker.cpp b/sdrbase/pipes/messagepipesgcworker.cpp
new file mode 100644
index 000000000..1ca839232
--- /dev/null
+++ b/sdrbase/pipes/messagepipesgcworker.cpp
@@ -0,0 +1,115 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+// (at your option) any later version.                                           //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#include "feature/feature.h"
+#include "maincore.h"
+#include "messagepipescommon.h"
+#include "messagepipesgcworker.h"
+
+MessagePipesGCWorker::MessagePipesGCWorker() :
+    m_running(false),
+    m_c2fMutex(nullptr),
+    m_c2fQueues(nullptr),
+    m_c2fFeatures(nullptr)
+{}
+
+MessagePipesGCWorker::~MessagePipesGCWorker()
+{}
+
+void MessagePipesGCWorker::startWork()
+{
+    connect(&m_gcTimer, SIGNAL(timeout()), this, SLOT(processGC()));
+    m_gcTimer.start(10000); // collect garbage every 10s
+    m_running = true;
+}
+
+void MessagePipesGCWorker::stopWork()
+{
+    m_running = false;
+    m_gcTimer.stop();
+    disconnect(&m_gcTimer, SIGNAL(timeout()), this, SLOT(processGC()));
+}
+
+void MessagePipesGCWorker::processGC()
+{
+    // qDebug("MessagePipesGCWorker::processGC");
+    if (m_c2fMutex)
+    {
+        QMutexLocker mlock(m_c2fMutex);
+        QMap<MessagePipesCommon::ChannelRegistrationKey, QList<Feature*>>::iterator fIt = m_c2fFeatures->begin();
+
+        // check deleted channels and features
+        for (;fIt != m_c2fFeatures->end(); ++fIt)
+        {
+            MessagePipesCommon::ChannelRegistrationKey channelKey = fIt.key();
+            const ChannelAPI *channel = channelKey.m_channel;
+
+            if (MainCore::instance()->existsChannel(channel)) // look for deleted features
+            {
+                QList<Feature*>& features = fIt.value();
+                int i = 0;
+
+                while (i < features.size())
+                {
+                    if (MainCore::instance()->existsFeature(features[i])) {
+                        i++;
+                    }
+                    else
+                    {
+                        features.removeAt(i);
+                        m_c2fQueues->operator[](channelKey).removeAt(i);
+                    }
+                }
+            }
+            else // channel was destroyed
+            {
+                QList<Feature*>& features = fIt.value();
+
+                for (int i = 0; i < features.size(); i++)
+                {
+                    MessagePipesCommon::MsgReportChannelDeleted *msg = MessagePipesCommon::MsgReportChannelDeleted::create(
+                        m_c2fQueues->operator[](channelKey)[i], channelKey);
+                    features[i]->getInputMessageQueue()->push(msg);
+                }
+            }
+        }
+
+        // remove keys with empty features
+        fIt = m_c2fFeatures->begin();
+
+        while (fIt != m_c2fFeatures->end())
+        {
+            if (fIt.value().size() == 0) {
+                fIt = m_c2fFeatures->erase(fIt);
+            } else {
+                ++fIt;
+            }
+        }
+
+        // remove keys with empty message queues
+        QMap<MessagePipesCommon::ChannelRegistrationKey, QList<MessageQueue*>>::iterator qIt = m_c2fQueues->begin();
+
+        while (qIt != m_c2fQueues->end())
+        {
+            if (qIt.value().size() == 0) {
+                qIt = m_c2fQueues->erase(qIt);
+            } else {
+                ++qIt;
+            }
+        }
+    }
+}
diff --git a/sdrbase/pipes/messagepipesgcworker.h b/sdrbase/pipes/messagepipesgcworker.h
new file mode 100644
index 000000000..2f2c198cc
--- /dev/null
+++ b/sdrbase/pipes/messagepipesgcworker.h
@@ -0,0 +1,63 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2020 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+// (at your option) any later version.                                           //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef SDRBASE_PIPES_MESSAGEPIPESGCWORKER_H_
+#define SDRBASE_PIPES_MESSAGEPIPESGCWORKER_H_
+
+#include <QObject>
+#include <QTimer>
+
+#include "export.h"
+
+#include "messagepipescommon.h"
+
+class QMutex;
+
+class SDRBASE_API MessagePipesGCWorker : public QObject
+{
+    Q_OBJECT
+public:
+    MessagePipesGCWorker();
+    ~MessagePipesGCWorker();
+
+    void setC2FRegistrations(
+        QMutex *c2fMutex,
+        QMap<MessagePipesCommon::ChannelRegistrationKey, QList<MessageQueue*>> *c2fQueues,
+        QMap<MessagePipesCommon::ChannelRegistrationKey, QList<Feature*>> *c2fFeatures
+    )
+    {
+        m_c2fMutex = c2fMutex;
+        m_c2fQueues = c2fQueues;
+        m_c2fFeatures = c2fFeatures;
+    }
+
+    void startWork();
+    void stopWork();
+    bool isRunning() const { return m_running; }
+
+private:
+    bool m_running;
+    QMutex *m_c2fMutex;
+    QMap<MessagePipesCommon::ChannelRegistrationKey, QList<MessageQueue*>> *m_c2fQueues ;
+    QMap<MessagePipesCommon::ChannelRegistrationKey, QList<Feature*>> *m_c2fFeatures;
+    QTimer m_gcTimer;
+
+private slots:
+    void processGC(); //!< Collect garbage
+};
+
+#endif