Ref T171, use a shared completer for callsign completion

* CSharedStringListCompleter utility class supporting timestamp checks
* avoid unnecessary DBus transfer
* less memory consumption

Remark: No totally clear if a QCompleter can be shared, but I have not noticed a problem so far

src/blackgui/components/callsigncompleter.cpp

@@ -33,6 +33,7 @@ namespace BlackGui
             ui->setupUi(this);
             CUpperCaseValidator *ucv = new CUpperCaseValidator(ui->le_Callsign);
             ui->le_Callsign->setValidator(ucv);
+            ui->le_Callsign->setCompleter(*completer());
             ui->led_Status->setToolTips("connected", "disconnected");
             ui->led_Status->setShape(CLedWidget::Rounded);
             ui->led_Status->setToolTips("network connected", "network disconnected", "data");
@@ -68,19 +69,10 @@ namespace BlackGui
         {
             if (!sGui || sGui->isShuttingDown()) { return; }
             if (!sGui->getIContextNetwork()) { return; }
+            if (completer()->wasUpdatedWithinTime(1500)) { return; } // avoid context call via DBus
             m_validCallsigns = sGui->getIContextNetwork()->getAircraftInRangeCallsigns();
             const QStringList modelData = m_validCallsigns.getCallsignStrings(true);
-            if (!m_currentCompleter)
-            {
-                m_currentCompleter = new QCompleter(modelData, ui->le_Callsign);
-                ui->le_Callsign->setCompleter(m_currentCompleter);
-            }
-            else
-            {
-                QStringListModel *model = qobject_cast<QStringListModel *>(m_currentCompleter->model());
-                Q_ASSERT(model);
-                model->setStringList(modelData);
-            }
+            completer()->updateData(modelData, 2000);
             ui->led_Status->setTriState(500);
         }
 
@@ -102,15 +94,13 @@ namespace BlackGui
         void CCallsignCompleter::onChangedConnectionStatus(INetwork::ConnectionStatus from, INetwork::ConnectionStatus to)
         {
             Q_UNUSED(from);
-            const bool on = (INetwork::Connected == to);
-            ui->led_Status->setOn(on);
+            const bool connected = (INetwork::Connected == to);
+            ui->led_Status->setOn(connected);
             ui->le_Callsign->clear();
-            ui->le_Callsign->setEnabled(on);
-            if (!on)
+            ui->le_Callsign->setEnabled(connected);
+            if (!connected)
             {
-                QStringListModel *model = qobject_cast<QStringListModel *>(m_currentCompleter->model());
-                Q_ASSERT(model);
-                model->setStringList(QStringList());
+                completer()->clearData();
             }
         }
 
@@ -120,5 +110,11 @@ namespace BlackGui
             if (!CCallsign::isValidAircraftCallsign(callsignString)) { return false; }
             return m_validCallsigns.contains(CCallsign(callsignString));
         }
+
+        CSharedStringListCompleter *CCallsignCompleter::completer()
+        {
+            static CSharedStringListCompleter *c = new CSharedStringListCompleter();
+            return c;
+        }
     } // ns
 } // ns

src/blackgui/components/callsigncompleter.h

@@ -13,6 +13,7 @@
 #define BLACKGUI_COMPONENTS_CALLSIGNCOMPLETER_H
 
 #include "blackgui/blackguiexport.h"
+#include "blackgui/sharedstringlistcompleter.h"
 #include "blackmisc/digestsignal.h"
 #include "blackmisc/aviation/callsignset.h"
 #include "blackcore/network.h"
@@ -63,8 +64,10 @@ namespace BlackGui
             void onChangedConnectionStatus(BlackCore::INetwork::ConnectionStatus from, BlackCore::INetwork::ConnectionStatus to);
             bool isValidKnownCallsign(const QString &callsignString) const;
 
+            //! Shared completer data
+            static CSharedStringListCompleter *completer();
+
             QScopedPointer <Ui::CCallsignCompleter> ui;
-            QCompleter *m_currentCompleter = nullptr;
             BlackMisc::Aviation::CCallsignSet m_validCallsigns;
             BlackMisc::CDigestSignal m_dsAircraftsInRangeChanged { this, &CCallsignCompleter::onChangedAircraftInRange, 5000, 5 };
         };

src/blackgui/sharedstringlistcompleter.cpp

@@ -0,0 +1,42 @@
+/* Copyright (C) 2017
+ * swift project Community / Contributors
+ *
+ * This file is part of swift Project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#include "sharedstringlistcompleter.h"
+#include <QStringListModel>
+#include <QDateTime>
+
+namespace BlackGui
+{
+    bool CSharedStringListCompleter::updateData(const QStringList &data, int cacheTimeMs)
+    {
+        QStringListModel *model = qobject_cast<QStringListModel *>(m_completer->model());
+        Q_ASSERT_X(model, Q_FUNC_INFO, "Model missing");
+        bool updated = false;
+        const qint64 now = QDateTime::currentMSecsSinceEpoch();
+        if (model->rowCount() != data.size() || (now - m_lastUpdated) > cacheTimeMs)
+        {
+            // quick check, different size means data changed -> update
+            // otherwise rely on time
+            m_lastUpdated = now;
+            model->setStringList(data);
+            updated = true;
+        }
+        return updated;
+    }
+
+    void CSharedStringListCompleter::clearData()
+    {
+        this->updateData(QStringList(), 0);
+    }
+
+    bool CSharedStringListCompleter::wasUpdatedWithinTime(int checkTimeMs) const
+    {
+        return (QDateTime::currentMSecsSinceEpoch() - m_lastUpdated) <= checkTimeMs;
+    }
+} // ns

src/blackgui/sharedstringlistcompleter.h

@@ -0,0 +1,54 @@
+/* Copyright (C) 2017
+ * swift project Community / Contributors
+ *
+ * This file is part of swift Project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKGUI_SHAREDSTRINGLISTCOMPLETER_H
+#define BLACKGUI_SHAREDSTRINGLISTCOMPLETER_H
+
+#include "blackgui/blackguiexport.h"
+
+#include <QCompleter>
+#include <QStringList>
+#include <QScopedPointer>
+
+namespace BlackGui
+{
+    /*!
+     * Completer shared among multiple UI elements.
+     * Normally used as static member
+     */
+    class BLACKGUI_EXPORT CSharedStringListCompleter
+    {
+    public:
+        //! Constructor
+        CSharedStringListCompleter() {}
+
+        //! Update data
+        bool updateData(const QStringList &data, int cacheTimeMs);
+
+        //! Clear completer data
+        void clearData();
+
+        //! Was updated within check time
+        bool wasUpdatedWithinTime(int checkTimeMs) const;
+
+        //! Completer
+        QCompleter *completer() const { return m_completer.data(); }
+
+        //! Convert to completer
+        operator QCompleter *() const { return m_completer.data(); }
+
+    private:
+        qint64 m_lastUpdated = 0;
+        QScopedPointer<QCompleter> m_completer { new QCompleter(QStringList()) }; // empty list required to init model
+    };
+} // ns
+
+#endif // guard