From 8535688605de821c30a33951b4d520de1258d926 Mon Sep 17 00:00:00 2001
From: Christian Prochaska <christian.prochaska@genode-labs.com>
Date: Tue, 10 Mar 2020 17:51:15 +0100
Subject: [PATCH] qt5: handle Genode signals as Qt signals in QPA plugin

Fixes #3688
---
 .../qt5/qpa_nitpicker/qnitpickerplatformwindow.h | 13 +++++++++++++
 repos/libports/lib/mk/qt5_qpa_nitpicker.mk       |  1 +
 .../platforms/nitpicker/qgenodeclipboard.cpp     |  6 +++++-
 .../platforms/nitpicker/qgenodeclipboard.h       | 16 +++++++++++++++-
 .../nitpicker/qnitpickerplatformwindow.cpp       | 12 ++++++++++--
 5 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/repos/libports/include/qt5/qpa_nitpicker/qnitpickerplatformwindow.h b/repos/libports/include/qt5/qpa_nitpicker/qnitpickerplatformwindow.h
index 1d1593ecd..1a423904b 100644
--- a/repos/libports/include/qt5/qpa_nitpicker/qnitpickerplatformwindow.h
+++ b/repos/libports/include/qt5/qpa_nitpicker/qnitpickerplatformwindow.h
@@ -96,8 +96,21 @@ class QNitpickerPlatformWindow : public QObject, public QPlatformWindow
 
 		QString _sanitize_label(QString label);
 
+		/*
+		 * Genode signals are handled as Qt signals to avoid blocking in the
+		 * Genode signal handler, which could cause nested signal handler
+		 * execution.
+		 */
+
+	private Q_SLOTS:
+
 		void _handle_input();
 		void _handle_mode_changed();
+		
+	Q_SIGNALS:
+
+		void _input();
+		void _mode_changed();
 
 	public:
 
diff --git a/repos/libports/lib/mk/qt5_qpa_nitpicker.mk b/repos/libports/lib/mk/qt5_qpa_nitpicker.mk
index 21c6e8e5c..b2b6cbace 100644
--- a/repos/libports/lib/mk/qt5_qpa_nitpicker.mk
+++ b/repos/libports/lib/mk/qt5_qpa_nitpicker.mk
@@ -16,6 +16,7 @@ SRC_CC += main.cpp \
           qnitpickerintegration.cpp \
           qnitpickerplatformwindow.cpp \
           qnitpickerwindowsurface.cpp \
+          moc_qgenodeclipboard.cpp \
           moc_qnitpickerplatformwindow.cpp \
           moc_qnitpickerwindowsurface.cpp \
           moc_qnitpickerintegrationplugin.cpp
diff --git a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.cpp b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.cpp
index f999a6264..304f2a241 100644
--- a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.cpp
+++ b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.cpp
@@ -28,7 +28,7 @@ static constexpr bool verbose = false;
 
 
 QGenodeClipboard::QGenodeClipboard(Genode::Env &env)
-: _clipboard_signal_handler(env.ep(), *this, &QGenodeClipboard::_handle_clipboard)
+: _clipboard_signal_handler(env.ep(), *this, &QGenodeClipboard::_clipboard_changed)
 {
 	try {
 
@@ -52,6 +52,10 @@ QGenodeClipboard::QGenodeClipboard(Genode::Env &env)
 
 		}
 	} catch (...) { }
+
+	connect(this, SIGNAL(_clipboard_changed()),
+	        this, SLOT(_handle_clipboard()),
+	        Qt::QueuedConnection);
 }
 
 
diff --git a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.h b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.h
index e3dc19a4a..3806a79b0 100644
--- a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.h
+++ b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qgenodeclipboard.h
@@ -28,8 +28,10 @@
 
 QT_BEGIN_NAMESPACE
 
-class QGenodeClipboard : public QPlatformClipboard
+class QGenodeClipboard : public QObject, public QPlatformClipboard
 {
+	Q_OBJECT
+
 	private:
 
 		Genode::Attached_rom_dataspace              *_clipboard_ds = nullptr;
@@ -41,8 +43,20 @@ class QGenodeClipboard : public QPlatformClipboard
 
 		QMember<QMimeData> _mimedata;
 
+		/*
+		 * Genode signals are handled as Qt signals to avoid blocking in the
+		 * Genode signal handler, which could cause nested signal handler
+		 * execution.
+		 */
+
+	private Q_SLOTS:
+
 		void _handle_clipboard();
 
+	Q_SIGNALS:
+
+		void _clipboard_changed();
+
 	public:
 
 		QGenodeClipboard(Genode::Env &env);
diff --git a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qnitpickerplatformwindow.cpp b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qnitpickerplatformwindow.cpp
index 24f14c4a3..e5230ffee 100644
--- a/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qnitpickerplatformwindow.cpp
+++ b/repos/libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/qnitpickerplatformwindow.cpp
@@ -509,9 +509,9 @@ QNitpickerPlatformWindow::QNitpickerPlatformWindow(Genode::Env &env, QWindow *wi
   _decoration(!window->flags().testFlag(Qt::Popup)),
   _egl_surface(EGL_NO_SURFACE),
   _input_signal_handler(_env.ep(), *this,
-                        &QNitpickerPlatformWindow::_handle_input),
+                        &QNitpickerPlatformWindow::_input),
   _mode_changed_signal_handler(_env.ep(), *this,
-                               &QNitpickerPlatformWindow::_handle_mode_changed),
+                               &QNitpickerPlatformWindow::_mode_changed),
   _touch_device(_init_touch_device())
 {
 	if (qnpw_verbose)
@@ -533,6 +533,14 @@ QNitpickerPlatformWindow::QNitpickerPlatformWindow(Genode::Env &env, QWindow *wi
 		_nitpicker_session.enqueue<Command::To_front>(_view_handle);
 		_nitpicker_session.execute();
 	}
+
+	connect(this, SIGNAL(_input()),
+	        this, SLOT(_handle_input()),
+	        Qt::QueuedConnection);
+
+	connect(this, SIGNAL(_mode_changed()),
+	        this, SLOT(_handle_mode_changed()),
+	        Qt::QueuedConnection);
 }
 
 QNitpickerPlatformWindow::~QNitpickerPlatformWindow()