FlightTasks: bool return values for clarity & introduce updateInitialize() to have input data fetching separated from the update()

src/lib/FlightTasks/FlightTasks.hpp

@@ -65,13 +65,13 @@ public:
 
 	/**
 	 * Call regularly in the control loop cycle to execute the task
-	 * @return 0 on success, <0 on error
+	 * @return true on success, false on error
 	 */
-	int update()
+	bool update()
 	{
 		if (is_any_task_active()) {
 			_subscription_array.update();
-			return _current_task->update();
+			return _current_task->updateInitialize() && _current_task->update();
 		}
 
 		return 1;
@@ -95,7 +95,7 @@ public:
 
 	/**
 	 * Switch to the next task in the available list (for testing)
-	 * @return 0 on success, <0 on error
+	 * @return true on success, false on error
 	 */
 	int switch_task()
 	{
@@ -105,13 +105,13 @@ public:
 	/**
 	 * Switch to a specific task (for normal usage)
 	 * @param task number to switch to
-	 * @return 0 on success, <0 on error
+	 * @return true on success, false on error
 	 */
 	int switch_task(int task_number)
 	{
 		/* switch to the running task, nothing to do */
 		if (task_number == _current_task_index) {
-			return 0;
+			return true;
 		}
 
 		/* disable the old task if there is any */
@@ -135,6 +135,7 @@ public:
 			return -1;
 		}
 
+		/* subscription failed */
 		if (!_current_task->initializeSubscriptions(_subscription_array)) {
 			_current_task->~FlightTask();
 			_current_task = nullptr;
@@ -144,7 +145,8 @@ public:
 
 		_subscription_array.forcedUpdate(); // make sure data is available for all new subscriptions
 
-		if (_current_task->activate()) {
+		/* activation failed */
+		if (!_current_task->updateInitialize() || !_current_task->activate()) {
 			_current_task->~FlightTask();
 			_current_task = nullptr;
 			_current_task_index = -1;
@@ -167,14 +169,7 @@ public:
 	 */
 	bool is_any_task_active() const { return _current_task; }
 
-	/**
-	 * Check if the task number exists
-	 * @return true if yes, false if not
-	 */
-	bool is_task_number_valid(int task_number) const { return task_number > -1 && task_number < _task_count; }
-
 private:
-	static constexpr int _task_count = 2;
 
 	/** union with all existing tasks: we use it to make sure that only the memory of the largest existing
 	 * task is needed, and to avoid using dynamic memory allocations.
@@ -185,8 +180,7 @@ private:
 
 		FlightTaskManual manual;
 		FlightTaskOrbit orbit;
-	};
-	TaskUnion _task_union; ///< storage for the currently active task
+	} _task_union; /*< storage for the currently active task */
 
 	FlightTask *_current_task = nullptr;
 	int _current_task_index = -1;

src/lib/FlightTasks/tasks/FlightTask.cpp

@@ -13,14 +13,13 @@ bool FlightTask::initializeSubscriptions(SubscriptionArray &subscription_array)
 	return true;
 }
 
-int FlightTask::activate()
+bool FlightTask::activate()
 {
 	_time_stamp_activate = hrt_absolute_time();
-	update(); /* to get subscriptions and evaluate them */
-	return 0;
+	return true;
 }
 
-int FlightTask::update()
+bool FlightTask::updateInitialize()
 {
 	_time_stamp_current = hrt_absolute_time();
 	_time = (_time_stamp_current - _time_stamp_activate) / 1e6f;
@@ -29,16 +28,16 @@ int FlightTask::update()
 	return _evaluate_vehicle_position();
 }
 
-int FlightTask::_evaluate_vehicle_position()
+bool FlightTask::_evaluate_vehicle_position()
 {
 	if ((_time_stamp_current - _sub_vehicle_local_position->get().timestamp) < _timeout) {
 		_position = matrix::Vector3f(&_sub_vehicle_local_position->get().x);
 		_velocity = matrix::Vector3f(&_sub_vehicle_local_position->get().vx);
 		_yaw = _sub_vehicle_local_position->get().yaw;
-		return 0;
+		return true;
 
 	} else {
 		_velocity.zero(); /* default velocity is all zero */
-		return -1;
+		return false;
 	}
 }

src/lib/FlightTasks/tasks/FlightTask.hpp

@@ -57,6 +57,8 @@ public:
 		Block(parent, name)
 	{ }
 
+	virtual ~FlightTask() = default;
+
 	/**
 	 * initialize the uORB subscriptions using an array
 	 * @return true on success, false on error
@@ -65,17 +67,22 @@ public:
 
 	/**
 	 * Call once on the event where you switch to the task
-	 * @return 0 on success, <0 on error
+	 * @return true on success, false on error
 	 */
-	virtual int activate();
+	virtual bool activate();
 
-	virtual ~FlightTask() = default;
+	/**
+	 * Call before activate() or update()
+	 * to initialize time and input data
+	 * @return true on success, false on error
+	 */
+	virtual bool updateInitialize();
 
 	/**
 	 * To be called regularly in the control loop cycle to execute the task
-	 * @return 0 on success, <0 on error
+	 * @return true on success, false on error
 	 */
-	virtual int update();
+	virtual bool update() = 0;
 
 	/**
 	 * Get the output data
@@ -119,5 +126,5 @@ private:
 
 	vehicle_local_position_setpoint_s _vehicle_local_position_setpoint; /**< Output position setpoint that every task has */
 
-	int _evaluate_vehicle_position();
+	bool _evaluate_vehicle_position();
 };

src/lib/FlightTasks/tasks/FlightTaskManual.cpp

@@ -88,11 +88,13 @@ bool FlightTaskManual::initializeSubscriptions(SubscriptionArray &subscription_a
 	return true;
 }
 
-int FlightTaskManual::update()
+bool FlightTaskManual::updateInitialize()
 {
-	int ret = FlightTask::update();
-	ret += _evaluate_sticks();
+	return FlightTask::updateInitialize() && _evaluate_sticks();
+}
 
+bool FlightTaskManual::update()
+{
 	/* prepare stick input */
 	Vector2f stick_xy(_sticks.data()); /**< horizontal two dimensional stick input within a unit circle */
 
@@ -142,10 +144,10 @@ int FlightTaskManual::update()
 	}
 
 	_set_position_setpoint(_hold_position);
-	return ret;
+	return true;
 }
 
-int FlightTaskManual::_evaluate_sticks()
+bool FlightTaskManual::_evaluate_sticks()
 {
 	if ((_time_stamp_current - _sub_manual_control_setpoint->get().timestamp) < _timeout) {
 		/* get data and scale correctly */
@@ -159,11 +161,11 @@ int FlightTaskManual::_evaluate_sticks()
 		_sticks(1) = math::expo_deadzone(_sticks(1), _xy_vel_man_expo.get(), _hold_dz.get());
 		_sticks(2) = math::expo_deadzone(_sticks(2), _z_vel_man_expo.get(), _hold_dz.get());
 
-		return 0;
+		return true;
 
 	} else {
 		_sticks.zero(); /* default is all zero */
-		return -1;
+		return false;
 	}
 }
 

src/lib/FlightTasks/tasks/FlightTaskManual.hpp

@@ -56,7 +56,9 @@ public:
 
 	bool initializeSubscriptions(SubscriptionArray &subscription_array) override;
 
-	int update() override;
+	bool updateInitialize() override;
+
+	bool update() override;
 
 protected:
 	matrix::Vector<float, 4> _sticks;
@@ -77,7 +79,7 @@ private:
 
 	matrix::Vector3f _hold_position; /**< position at which the vehicle stays while the input is zero velocity */
 
-	int _evaluate_sticks();
+	bool _evaluate_sticks();
 
 
 	/* --- Acceleration Smoothing --- */

src/lib/FlightTasks/tasks/FlightTaskOrbit.cpp

@@ -49,9 +49,9 @@ FlightTaskOrbit::FlightTaskOrbit(control::SuperBlock *parent, const char *name)
 	FlightTaskManual(parent, name)
 {}
 
-int FlightTaskOrbit::activate()
+bool FlightTaskOrbit::activate()
 {
-	int ret = FlightTaskManual::activate();
+	bool ret = FlightTaskManual::activate();
 	_r = 1.f;
 	_v =  0.5f;
 	_z = _position(2);
@@ -60,10 +60,8 @@ int FlightTaskOrbit::activate()
 	return ret;
 }
 
-int FlightTaskOrbit::update()
+bool FlightTaskOrbit::update()
 {
-	int ret = FlightTaskManual::update();
-
 	_r += _sticks(0) * _deltatime;
 	_r = math::constrain(_r, 1.f, 20.f);
 	_v -= _sticks(1) * _deltatime;
@@ -85,5 +83,5 @@ int FlightTaskOrbit::update()
 	_set_position_setpoint(Vector3f(NAN, NAN, _z));
 	_set_velocity_setpoint(Vector3f(velocity_xy(0), velocity_xy(1), 0.f));
 	_set_yaw_setpoint(yaw);
-	return ret;
+	return true;
 }

src/lib/FlightTasks/tasks/FlightTaskOrbit.hpp

@@ -50,9 +50,9 @@ public:
 
 	virtual ~FlightTaskOrbit() = default;
 
-	int activate() override;
+	bool activate() override;
 
-	int update() override;
+	bool update() override;
 
 private: