[calamares] Allow WM close button

- remove hide-close-button hack
 - refactor code in viewmanager for confirming quit
 - hook up confirm-and-quit to WM close button
 - also works for alt-F4 and other quit methods
 - while here, update copyright year

FIXES #870

src/calamares/CalamaresWindow.cpp

@@ -1,7 +1,7 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
  *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
- *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017-2018, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -30,6 +30,7 @@
 
 #include <QApplication>
 #include <QBoxLayout>
+#include <QCloseEvent>
 #include <QDesktopWidget>
 #include <QLabel>
 #include <QTreeView>
@@ -37,10 +38,8 @@
 CalamaresWindow::CalamaresWindow( QWidget* parent )
     : QWidget( parent )
     , m_debugWindow( nullptr )
+    , m_viewManager( nullptr )
 {
-    // Hide close button
-    setWindowFlags( Qt::Window | Qt::WindowTitleHint | Qt::CustomizeWindowHint );
-
     CALAMARES_RETRANSLATE(
         setWindowTitle( tr( "%1 Installer" )
                         .arg( *Calamares::Branding::ProductName ) );
@@ -139,10 +138,10 @@ CalamaresWindow::CalamaresWindow( QWidget* parent )
     CalamaresUtils::unmarginLayout( sideLayout );
     CalamaresUtils::unmarginLayout( mainLayout );
 
-    Calamares::ViewManager* vm = Calamares::ViewManager::instance( this );
-    connect( vm, &Calamares::ViewManager::enlarge, this, &CalamaresWindow::enlarge );
+    m_viewManager = Calamares::ViewManager::instance( this );
+    connect( m_viewManager, &Calamares::ViewManager::enlarge, this, &CalamaresWindow::enlarge );
 
-    mainLayout->addWidget( vm->centralWidget() );
+    mainLayout->addWidget( m_viewManager->centralWidget() );
 }
 
 void
@@ -156,3 +155,15 @@ CalamaresWindow::enlarge( QSize enlarge )
 
     resize( w, h );
 }
+
+void
+CalamaresWindow::closeEvent( QCloseEvent* event )
+{
+    if ( ( !m_viewManager ) || m_viewManager->confirmCancelInstallation() )
+    {
+        event->accept();
+        qApp->quit();
+    }
+    else
+        event->ignore();
+}

src/calamares/CalamaresWindow.h

@@ -1,7 +1,7 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
  *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
- *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017-2018, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -26,6 +26,7 @@
 namespace Calamares
 {
 class DebugWindow;
+class ViewManager;
 }
 
 /**
@@ -46,8 +47,12 @@ public slots:
      */
     void enlarge( QSize enlarge );
 
+protected:
+    virtual void closeEvent( QCloseEvent* e ) override;
+
 private:
-    QPointer< Calamares::DebugWindow > m_debugWindow;
+    QPointer< Calamares::DebugWindow > m_debugWindow;  // Managed by self
+    Calamares::ViewManager* m_viewManager;
 };
 
 #endif //CALAMARESWINDOW_H

src/libcalamaresui/ViewManager.cpp

@@ -1,7 +1,7 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
  *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
- *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017-2018, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -88,30 +88,8 @@ ViewManager::ViewManager( QObject* parent )
     connect( m_back, &QPushButton::clicked, this, &ViewManager::back );
     m_back->setEnabled( false );
 
-    connect( m_quit, &QPushButton::clicked,
-             this, [this]()
-    {
-        // If it's NOT the last page of the last step, we ask for confirmation
-        if ( !( m_currentStep == m_steps.count() -1 &&
-                m_steps.last()->isAtEnd() ) )
-        {
-            QMessageBox mb( QMessageBox::Question,
-                            tr( "Cancel installation?" ),
-                            tr( "Do you really want to cancel the current install process?\n"
-                                "The installer will quit and all changes will be lost." ),
-                            QMessageBox::Yes | QMessageBox::No,
-                            m_widget );
-            mb.setDefaultButton( QMessageBox::No );
-            mb.button( QMessageBox::Yes )->setText( tr( "&Yes" ) );
-            mb.button( QMessageBox::No )->setText( tr( "&No" ) );
-            int response = mb.exec();
-            if ( response == QMessageBox::Yes )
-                qApp->quit();
-        }
-        else // Means we're at the end, no need to confirm.
-            qApp->quit();
-    } );
-
+    connect( m_quit, &QPushButton::clicked, this,
+             [this]() { if ( this->confirmCancelInstallation() ) qApp->quit(); } );
     connect( JobQueue::instance(), &JobQueue::failed,
              this, &ViewManager::onInstallationFailed );
     connect( JobQueue::instance(), &JobQueue::finished,
@@ -302,4 +280,26 @@ ViewManager::back()
     }
 }
 
+bool ViewManager::confirmCancelInstallation()
+{
+    // If it's NOT the last page of the last step, we ask for confirmation
+    if ( !( m_currentStep == m_steps.count() -1 &&
+            m_steps.last()->isAtEnd() ) )
+    {
+        QMessageBox mb( QMessageBox::Question,
+                        tr( "Cancel installation?" ),
+                        tr( "Do you really want to cancel the current install process?\n"
+                            "The installer will quit and all changes will be lost." ),
+                        QMessageBox::Yes | QMessageBox::No,
+                        m_widget );
+        mb.setDefaultButton( QMessageBox::No );
+        mb.button( QMessageBox::Yes )->setText( tr( "&Yes" ) );
+        mb.button( QMessageBox::No )->setText( tr( "&No" ) );
+        int response = mb.exec();
+        return response == QMessageBox::Yes;
+    }
+    else // Means we're at the end, no need to confirm.
+        return true;
 }
+
+}  // namespace

src/libcalamaresui/ViewManager.h

@@ -1,7 +1,7 @@
 /* === This file is part of Calamares - <http://github.com/calamares> ===
  *
  *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
- *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017-2018, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -86,6 +86,13 @@ public:
      */
     int currentStepIndex() const;
 
+    /**
+     * @ brief Called when "Cancel" is clicked; asks for confirmation.
+     * Other means of closing Calamares also call this method, e.g. alt-F4.
+     * At the end of installation, no confirmation is asked. Returns true
+     * if the user confirms closing the window.
+     */
+    bool confirmCancelInstallation();
 
 public slots:
     /**