Fix PTZ action commands getting ignored

Switching to the prochandler API broke the action source because the
proc handler lambdas were ignoring all calls from threads other than the
GUI thread. This was done because the calldata structure usually lives
on the callers stack, and if a call was queued on the correct thread,
e.g. by calling QMetaObject::invokeMethod(), then the calldata would be
gone by the time the method ran. However, the action source triggers
don't come from the UI thread.

To fix this, rework the proc handlers to extract the calldata arguments
in the callers thread, and then use invokeMethod() to call the device
method, using the default Qt::AutoConnection mode so that calls from the
GUI thread are direct, but calls from other threads get queued. For most
methods this works fine because the calls are commands to the device.

The one exception is the ::get() method which needs to return data to
the caller. This is the one proc handler method that still needs to be
called by the GUI thread, and it gets ignored if it is not. This perhaps
could be fixed by using a BlockingQueued connection, but it is unclear
if it is needed and that change can be done in another patch.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Author: glikely

src/ptz-device.cpp

@@ -35,10 +35,6 @@
 			blog(LOG_ERROR, "PTZ proc_handler called without PTZDevice pointer"); \
 			return; \
 		} \
-		if (QThread::currentThread() != ptz->thread()) { \
-			blog(LOG_WARNING, "PTZDevice proc_handler '%s'->%s() call from non-GUI thread; ignored", QT_TO_UTF8(ptz->objectName()), #_method); \
-			return; \
-		} \
 		ptz->_method(cd); \
 	}
 
@@ -172,39 +168,43 @@ void PTZDevice::move(calldata_t *cd)
 	double p = 0, t = 0, z = 0, f = 0;
 
 	if (calldata_get_float(cd, "pan", &p) + calldata_get_float(cd, "tilt", &t))
-		pantilt(p, t);
+		QMetaObject::invokeMethod(this, &PTZDevice::pantilt, p, t);
 
 	if (calldata_get_float(cd, "zoom", &z))
-		zoom(z);
+		QMetaObject::invokeMethod(this, &PTZDevice::zoom, z);
 
 	if (calldata_get_float(cd, "focus", &f))
-		focus(f);
+		QMetaObject::invokeMethod(this, &PTZDevice::focus, f);
 }
 
 void PTZDevice::move_abs(calldata_t *cd)
 {
 	double p = 0, t = 0, z = 0, f = 0;
 
 	if (calldata_get_float(cd, "pan", &p) + calldata_get_float(cd, "tilt", &t))
-		pantilt_abs(p, t);
+		QMetaObject::invokeMethod(this, &PTZDevice::pantilt_abs, p, t);
 
 	if (calldata_get_float(cd, "zoom", &z))
-		zoom_abs(z);
+		QMetaObject::invokeMethod(this, &PTZDevice::zoom_abs, z);
 
 	if (calldata_get_float(cd, "focus", &f))
-		focus_abs(f);
+		QMetaObject::invokeMethod(this, &PTZDevice::focus_abs, f);
 }
 
 void PTZDevice::move_rel(calldata_t *cd)
 {
 	double p = 0, t = 0;
 
 	if (calldata_get_float(cd, "pan", &p) + calldata_get_float(cd, "tilt", &t))
-		pantilt_rel(p, t);
+		QMetaObject::invokeMethod(this, &PTZDevice::pantilt_rel, p, t);
 }
 
 void PTZDevice::get(calldata_t *cd) const
 {
+	if (QThread::currentThread() != thread()) {
+		ptz_log(LOG_ERROR, "get(calldata) called from non-GUI thread; ignored");
+		return;
+	}
 	QString arg = calldata_string(cd, "property");
 	if (arg == "power_on")
 		calldata_set_bool(cd, "power_on", obs_data_get_bool(settings, "power_on"));
@@ -217,31 +217,31 @@ void PTZDevice::set(calldata_t *cd)
 {
 	bool enable;
 	if (calldata_get_bool(cd, "focus_af_enabled", &enable))
-		set_autofocus(enable);
+		QMetaObject::invokeMethod(this, &PTZDevice::set_autofocus, enable);
 	bool trigger;
 	if (calldata_get_bool(cd, "focus_onetouch_trigger", &trigger) && trigger)
-		focus_onetouch();
+		QMetaObject::invokeMethod(this, &PTZDevice::focus_onetouch);
 }
 
 void PTZDevice::preset_save(calldata_t *cd)
 {
 	long long id;
 	if (calldata_get_int(cd, "preset_id", &id))
-		memory_set(id);
+		QMetaObject::invokeMethod(this, &PTZDevice::memory_set, (int)id);
 }
 
 void PTZDevice::preset_recall(calldata_t *cd)
 {
 	long long id;
 	if (calldata_get_int(cd, "preset_id", &id))
-		memory_recall(id);
+		QMetaObject::invokeMethod(this, "memory_recall", (int)id);
 }
 
 void PTZDevice::preset_clear(calldata_t *cd)
 {
 	long long id;
 	if (calldata_get_int(cd, "preset_id", &id))
-		memory_reset(id);
+		QMetaObject::invokeMethod(this, &PTZDevice::memory_reset, (int)id);
 }
 
 void PTZDevice::getDefaults(OBSData config) const

src/ptz-device.hpp

@@ -109,7 +109,7 @@ class PTZDevice : public QObject {
 	 * zoom: range[0.0, 1.0], 0.0 == wide angle, 1.0 == telephoto
 	 * focus: range[0.0, 1.0], 0.0 == far focus, 1.0 == near focus
 	 */
-protected:
+protected slots:
 	void stop();
 	void pantilt(double pan, double tilt);
 	virtual void pantilt_rel(double pan, double tilt)
@@ -142,10 +142,9 @@ class PTZDevice : public QObject {
 	virtual void memory_recall(int i) { Q_UNUSED(i); }
 	virtual void memory_reset(int i) { Q_UNUSED(i); }
 
-protected slots:
-	void stop(calldata_t *) { stop(); }
-	void pantilt_home(calldata_t *) { pantilt_home(); }
-	void pantilt_set_home(calldata_t *) { pantilt_set_home(); };
+	void stop(calldata_t *) { QMetaObject::invokeMethod(this, "stop"); }
+	void pantilt_home(calldata_t *) { QMetaObject::invokeMethod(this, "pantilt_home"); }
+	void pantilt_set_home(calldata_t *) { QMetaObject::invokeMethod(this, "pantilt_set_home"); }
 	void move(calldata_t *cd);
 	void move_abs(calldata_t *cd);
 	void move_rel(calldata_t *cd);