refs #204 stub project for XBus, an X-Plane plugin (not client plugin) which will communicate with the client

src/blacksim/xplane/xbus/utils.h

@@ -0,0 +1,87 @@
+/*  Copyright (C) 2013 VATSIM Community / contributors
+ *  This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BLACKSIM_XBUS_UTILS_H
+#define BLACKSIM_XBUS_UTILS_H
+
+#include <XPLM/XPLMDefs.h>
+#include <XPLM/XPLMPlugin.h>
+#include <XPLM/XPLMProcessing.h>
+#include <QApplication>
+#include <QSharedPointer>
+
+/*!
+ * \file
+ */
+
+/*!
+ * QApplication subclass used by XBus.
+ *
+ * Only one instance of QApplication is allowed per process, so if any other
+ * X-Plane plugin, completely unrelated to this pilot client, wants to use the
+ * Qt framework, they can simply copy & paste this class into their project
+ * and both X-Plane plugins will be able to share a single QApplication safely.
+ */
+class QSharedApplication : public QApplication
+{
+    Q_OBJECT
+
+    QWeakPointer<QApplication> m_weakptr;
+
+    QSharedApplication(QSharedPointer<QApplication> &ptr, int argc, char **argv) : QApplication(argc, argv)
+    {
+        ptr.reset(this);
+        m_weakptr = ptr;
+    }
+
+public:
+    static QSharedPointer<QApplication> sharedInstance()
+    {
+        QSharedPointer<QApplication> ptr;
+        if (! instance())
+        {
+            static int argc = 1;
+            static char *argv[] = { "X-Plane" };
+            new QSharedApplication(ptr, argc, argv);
+        }
+        return qobject_cast<QSharedApplication*>(instance())->m_weakptr;
+    }
+};
+
+/*!
+ * Runs the Qt event loop inside the X-Plane event loop.
+ */
+class QXPlaneEventLoop : public QObject
+{
+    Q_OBJECT
+
+    QXPlaneEventLoop(QObject *parent) : QObject(parent)
+    {
+        XPLMRegisterFlightLoopCallback(callback, -1, nullptr);
+    }
+
+    ~QXPlaneEventLoop()
+    {
+        XPLMUnregisterFlightLoopCallback(callback, nullptr);
+    }
+
+    static float callback(float, float, int, void *)
+    {
+        QApplication::processEvents();
+        QApplication::sendPostedEvents();
+        return -1;
+    }
+
+public:
+    static void exec()
+    {
+        if (! QApplication::instance()->findChild<QXPlaneEventLoop *>())
+        {
+            new QXPlaneEventLoop(QApplication::instance());
+        }
+    }
+};
+
+#endif // guard