[Qt] allow to execute a callback during splashscreen progress

src/qt/bitcoin.cpp

@@ -578,6 +578,7 @@ int main(int argc, char *argv[])
     //   Need to pass name here as CAmount is a typedef (see http://qt-project.org/doc/qt-5/qmetatype.html#qRegisterMetaType)
     //   IMPORTANT if it is no longer a typedef use the normal variant above
     qRegisterMetaType< CAmount >("CAmount");
+    qRegisterMetaType< std::function<void(void)> >("std::function<void(void)>");
 
     /// 3. Application identification
     // must be set before OptionsModel is initialized or translations are loaded,

src/qt/splashscreen.cpp

@@ -131,6 +131,7 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
     move(QApplication::desktop()->screenGeometry().center() - r.center());
 
     subscribeToCoreSignals();
+    installEventFilter(this);
 }
 
 SplashScreen::~SplashScreen()
@@ -138,6 +139,16 @@ SplashScreen::~SplashScreen()
     unsubscribeFromCoreSignals();
 }
 
+bool SplashScreen::eventFilter(QObject * obj, QEvent * ev) {
+    if (ev->type() == QEvent::KeyPress) {
+        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(ev);
+        if(keyEvent->text()[0] == 'q' && breakAction != nullptr) {
+            breakAction();
+        }
+    }
+    return QObject::eventFilter(obj, ev);
+}
+
 void SplashScreen::slotFinish(QWidget *mainWin)
 {
     Q_UNUSED(mainWin);
@@ -164,6 +175,18 @@ static void ShowProgress(SplashScreen *splash, const std::string &title, int nPr
     InitMessage(splash, title + strprintf("%d", nProgress) + "%");
 }
 
+void SplashScreen::setBreakAction(const std::function<void(void)> &action)
+{
+    breakAction = action;
+}
+
+static void SetProgressBreakAction(SplashScreen *splash, const std::function<void(void)> &action)
+{
+    QMetaObject::invokeMethod(splash, "setBreakAction",
+        Qt::QueuedConnection,
+        Q_ARG(std::function<void(void)>, action));
+}
+
 #ifdef ENABLE_WALLET
 void SplashScreen::ConnectWallet(CWallet* wallet)
 {
@@ -177,6 +200,7 @@ void SplashScreen::subscribeToCoreSignals()
     // Connect signals to client
     uiInterface.InitMessage.connect(boost::bind(InitMessage, this, _1));
     uiInterface.ShowProgress.connect(boost::bind(ShowProgress, this, _1, _2));
+    uiInterface.SetProgressBreakAction.connect(boost::bind(SetProgressBreakAction, this, _1));
 #ifdef ENABLE_WALLET
     uiInterface.LoadWallet.connect(boost::bind(&SplashScreen::ConnectWallet, this, _1));
 #endif

src/qt/splashscreen.h

@@ -5,6 +5,7 @@
 #ifndef BITCOIN_QT_SPLASHSCREEN_H
 #define BITCOIN_QT_SPLASHSCREEN_H
 
+#include <functional>
 #include <QSplashScreen>
 
 class CWallet;
@@ -35,6 +36,11 @@ public Q_SLOTS:
     /** Show message and progress */
     void showMessage(const QString &message, int alignment, const QColor &color);
 
+    /** Sets the break action */
+    void setBreakAction(const std::function<void(void)> &action);
+protected:
+    bool eventFilter(QObject * obj, QEvent * ev);
+
 private:
     /** Connect core signals to splash screen */
     void subscribeToCoreSignals();
@@ -49,6 +55,8 @@ private:
     int curAlignment;
 
     QList<CWallet*> connectedWallets;
+
+    std::function<void(void)> breakAction;
 };
 
 #endif // BITCOIN_QT_SPLASHSCREEN_H

src/ui_interface.h

@@ -97,6 +97,9 @@ public:
     /** Show progress e.g. for verifychain */
     boost::signals2::signal<void (const std::string &title, int nProgress)> ShowProgress;
 
+    /** Set progress break action (possible "cancel button" triggers that action) */
+    boost::signals2::signal<void (std::function<void(void)> action)> SetProgressBreakAction;
+
     /** New block has been accepted */
     boost::signals2::signal<void (bool, const CBlockIndex *)> NotifyBlockTip;