From 764e00d9cfd1da60b6d117a853b5b4a8b67000e5 Mon Sep 17 00:00:00 2001
From: David Rowe <david@ctrlaltstudio.com>
Date: Wed, 20 Jun 2018 15:48:40 +1200
Subject: [PATCH] Stop desktop app window's QML source from running when window
 is closed

---
 libraries/qml/src/qml/OffscreenSurface.cpp    |  7 +++++++
 .../ui/src/ui/TabletScriptingInterface.cpp    | 21 +++++++++++++++++++
 .../ui/src/ui/TabletScriptingInterface.h      |  3 +++
 3 files changed, 31 insertions(+)

diff --git a/libraries/qml/src/qml/OffscreenSurface.cpp b/libraries/qml/src/qml/OffscreenSurface.cpp
index 688f3fdb5f..f0c3dfdffd 100644
--- a/libraries/qml/src/qml/OffscreenSurface.cpp
+++ b/libraries/qml/src/qml/OffscreenSurface.cpp
@@ -286,6 +286,13 @@ void OffscreenSurface::loadInternal(const QUrl& qmlSource,
     if (QThread::currentThread() != thread()) {
         qFatal("Called load on a non-surface thread");
     }
+
+    // For desktop toolbar mode window: stop script when window is closed.
+    if (qmlSource.isEmpty()) {
+        getSurfaceContext()->engine()->quit();
+        return;
+    }
+
     // Synchronous loading may take a while; restart the deadlock timer
     QMetaObject::invokeMethod(qApp, "updateHeartbeat", Qt::DirectConnection);
 
diff --git a/libraries/ui/src/ui/TabletScriptingInterface.cpp b/libraries/ui/src/ui/TabletScriptingInterface.cpp
index 2c52e669a0..6f00e046af 100644
--- a/libraries/ui/src/ui/TabletScriptingInterface.cpp
+++ b/libraries/ui/src/ui/TabletScriptingInterface.cpp
@@ -648,6 +648,26 @@ void TabletProxy::loadQMLSource(const QVariant& path, bool resizable) {
     }
 }
 
+void TabletProxy::stopQMLSource() {
+    // For desktop toolbar mode dialogs.
+    if (!_toolbarMode || !_desktopWindow) {
+        qCDebug(uiLogging) << "tablet cannot clear QML because not desktop toolbar mode";
+        return;
+    }
+
+    auto root = _desktopWindow->asQuickItem();
+    if (root) {
+        QMetaObject::invokeMethod(root, "loadSource", Q_ARG(const QVariant&, ""));
+        if (!_currentPathLoaded.toString().isEmpty()) {
+            emit screenChanged(QVariant("QML"), "");
+        }
+        _currentPathLoaded = "";
+        _state = State::Home;
+    } else {
+        qCDebug(uiLogging) << "tablet cannot clear QML because _desktopWindow is null";
+    }
+}
+
 bool TabletProxy::pushOntoStack(const QVariant& path) {
     if (QThread::currentThread() != thread()) {
         bool result = false;
@@ -719,6 +739,7 @@ void TabletProxy::loadHomeScreen(bool forceOntoHomeScreen) {
             // close desktop window
             if (_desktopWindow->asQuickItem()) {
                 QMetaObject::invokeMethod(_desktopWindow->asQuickItem(), "setShown", Q_ARG(const QVariant&, QVariant(false)));
+                stopQMLSource();  // Stop the currently loaded QML running.
             }
         }
         _state = State::Home;
diff --git a/libraries/ui/src/ui/TabletScriptingInterface.h b/libraries/ui/src/ui/TabletScriptingInterface.h
index 1ab29ca3fd..2d37402d01 100644
--- a/libraries/ui/src/ui/TabletScriptingInterface.h
+++ b/libraries/ui/src/ui/TabletScriptingInterface.h
@@ -443,6 +443,9 @@ protected:
     bool _showRunningScripts { false };
 
     TabletButtonListModel _buttons;
+
+private:
+    void stopQMLSource();
 };
 
 Q_DECLARE_METATYPE(TabletProxy*);