fsfw/tasks/FixedSlotSequence.h

#ifndef FSFW_TASKS_FIXEDSLOTSEQUENCE_H_
#define FSFW_TASKS_FIXEDSLOTSEQUENCE_H_

#include "FixedSequenceSlot.h"
#include "../objectmanager/SystemObject.h"

#include <set>

/**
 * @brief	This class is the representation of a
 * 			Polling Sequence Table in software.
 * @details
 * The FixedSlotSequence object maintains the dynamic execution of
 * objects with stricter timing requirements for the FixedTimeslotTask.
 *
 * The main idea is to create a list of executable objects (for example
 * device handlers), to announce all handlers to the polling sequence and to
 * maintain a list of polling slot objects.
 * This slot list represents the Polling Sequence Table in software.
 *
 * Each polling slot contains information to indicate when and
 * which executable object shall be executed within a given polling period.
 * When adding a slot, a pointer to the executing task, a pointer to the
 * executable object and a step number can be passed. The step number will be
 * passed to the periodic handler.
 * The sequence is executed by iterating through the slot sequence and
 * executing the executable object in the correct timeslot.
 */
class FixedSlotSequence {
public:
	using SlotList = std::multiset<FixedSequenceSlot>;
	using SlotListIter = std::multiset<FixedSequenceSlot>::iterator;

	/**
	 * @brief	The constructor of the FixedSlotSequence object.
	 * @param	setLength	The period length, expressed in ms.
	 */
	FixedSlotSequence(uint32_t setLengthMs);

	/**
	 * @brief	The destructor of the FixedSlotSequence object.
	 * @details
	 * The destructor frees all allocated memory by iterating through the
	 * slotList and deleting all allocated resources.
	 */
	virtual ~FixedSlotSequence();

	/**
	 * @brief	This is a method to add an PollingSlot object to slotList.
	 *
	 * @details
	 * Here, a polling slot object is added to the slot list. It is appended
	 * to the end of the list. The list is currently NOT reordered.
	 * Afterwards, the iterator current is set to the beginning of the list.
	 * 	@param handlerId ID of the object to add
	 * 	@param setTime
	 * 	Value between (0 to 1) * slotLengthMs, when a FixedTimeslotTask
	 * 	will be called inside the slot period.
	 * 	@param setSequenceId
	 * 	ID which can be used to distinguish different task operations. This
	 * 	value will be passed to the executable function.
	 * 	@param
	 * 	@param
	 */
	void addSlot(object_id_t handlerId, uint32_t setTime, int8_t setSequenceId,
			ExecutableObjectIF* executableObject,
			PeriodicTaskIF* executingTask);

	/**
	 * @brief	Checks if the current slot shall be executed immediately
	 * 			after the one before.
	 * @details
	 * This allows to distinguish between grouped and separated handlers.
	 * @return 	- @c true if the slot has the same polling time as the previous
	 * 			- @c false else
	 */
	bool slotFollowsImmediately();

	/**
	 * @brief	This method returns the time until the next software
	 * 			component is invoked.
	 *
	 * @details
	 * This method is vitally important for the operation of the PST.
	 * By fetching the polling time of the current slot and that of the
	 * next one (or the first one, if the list end is reached)
	 * it calculates and returns the interval in milliseconds within
	 * which the handler execution shall take place.
	 * If the next slot has the same time as the current one, it is ignored
	 * until a slot with different time or the end of the PST is found.
	 */
	uint32_t getIntervalToNextSlotMs();

	/**
	 * @brief	This method returns the time difference between the current
	 * 			slot and the previous slot
	 *
	 * @details
	 * This method is vitally important for the operation of the PST.
	 * By fetching the polling time of the current slot and that of the previous
	 * one (or the last one, if the slot is the first one) it calculates and
	 * returns the interval in milliseconds that the handler execution shall
	 * be delayed.
	 */
	uint32_t getIntervalToPreviousSlotMs();

	/**
	 * @brief	This method returns the length of this FixedSlotSequence instance.
	 */
	uint32_t getLengthMs() const;

	/**
	 * @brief	The method to execute the device handler entered in the current
	 * 			PollingSlot object.
	 *
	 * @details
	 * Within this method the device handler object to be executed is chosen by
	 * looking up the handler address of the current slot in the handlerMap.
	 * Either the device handler's talkToInterface or its listenToInterface
	 * method is invoked, depending on the isTalking flag of the polling slot.
	 * After execution the iterator current is increased or, by reaching the
	 * end of slotList, reset to the beginning.
	 */
	void executeAndAdvance();

	/**
	 * @brief	An iterator that indicates the current polling slot to execute.
	 *
	 * @details	This is an iterator for slotList and always points to the
	 * 			polling slot which is executed next.
	 */
	SlotListIter current;

	/**
	 * @brief   Check and initialize slot list.
	 * @details
	 * Checks if timing is ok (must be ascending) and if all handlers were found.
	 * @return
	 */
	ReturnValue_t checkSequence() const;

	/**
	 * @brief   A custom check can be injected for the respective slot list.
	 * @details
	 * This can be used by the developer to check the validity of a certain
	 * sequence. The function will be run in the #checkSequence function.
	 * The general check will be continued for now if the custom check function
	 * fails but a diagnostic debug output will be given.
	 * @param customCheckFunction
	 */
	void addCustomCheck(ReturnValue_t (*customCheckFunction)(const SlotList &));

	/**
	 * @brief 	Perform any initialization steps required after the executing
	 * 			task has been created. This function should be called from the
	 * 			executing task!
	 * @return
	 */
	ReturnValue_t intializeSequenceAfterTaskCreation() const;

protected:

	/**
	 * @brief	This list contains all PollingSlot objects, defining order and
	 * 			execution time of the device handler objects.
	 *
	 * @details
	 * The slot list is a std:list object that contains all created
	 * PollingSlot instances. They are NOT ordered automatically, so by
	 * adding entries, the correct order needs to be ensured. By iterating
	 * through this list the polling sequence is executed. Two entries with
	 * identical polling times are executed immediately one after another.
	 */
	SlotList slotList;

	ReturnValue_t (*customCheckFunction)(const SlotList&) = nullptr;

	uint32_t lengthMs;
};

#endif /* FSFW_TASKS_FIXEDSLOTSEQUENCE_H_ */