QP/C  7.3.4
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QActive Class Reference

Active object class (based on the QHsm implementation strategy) More...

#include "qp.h"

Inheritance diagram for QActive:
QAsm QActiveDummy QMActive QTicker QXThread

Public Member Functions

void QActive_setAttr (QActive *const me, uint32_t attr1, void const *attr2)
 

Static Public Member Functions

void QActive_psInit (QSubscrList *const subscrSto, enum_t const maxSignal)
 

Public Attributes

QAsm super
 

Protected Member Functions

void QActive_ctor (QActive *const me, QStateHandler const initial)
 
void QActive_stop (QActive *const me)
 
void QActive_subscribe (QActive const *const me, enum_t const sig)
 
void QActive_unsubscribe (QActive const *const me, enum_t const sig)
 
void QActive_unsubscribeAll (QActive const *const me)
 
bool QActive_defer (QActive const *const me, struct QEQueue *const eq, QEvt const *const e)
 
bool QActive_recall (QActive *const me, struct QEQueue *const eq)
 
uint_fast16_t QActive_flushDeferred (QActive const *const me, struct QEQueue *const eq, uint_fast16_t const num)
 
- Protected Member Functions inherited from QAsm
void QAsm_ctor (QAsm *const me)
 
QState QHsm_top (QHsm const *const me, QEvt const *const e)
 

Protected Attributes

uint8_t prio
 
uint8_t pthre
 
QACTIVE_THREAD_TYPE thread
 
QACTIVE_OS_OBJ_TYPE osObject
 
QACTIVE_EQUEUE_TYPE eQueue
 
uint8_t prio_dis
 
uint8_t pthre_dis
 
- Protected Attributes inherited from QAsm
struct QAsmVtable const * vptr
 
union QAsmAttr state
 
union QAsmAttr temp
 

Private Member Functions

void QActive_start_ (QActive *const me, QPrioSpec const prioSpec, QEvt const **const qSto, uint_fast16_t const qLen, void *const stkSto, uint_fast16_t const stkSize, void const *const par)
 
void QActive_register_ (QActive *const me)
 
void QActive_unregister_ (QActive *const me)
 
bool QActive_post_ (QActive *const me, QEvt const *const e, uint_fast16_t const margin, void const *const sender)
 
void QActive_postLIFO_ (QActive *const me, QEvt const *const e)
 
QEvt const * QActive_get_ (QActive *const me)
 
void QActive_evtLoop_ (QActive *const me)
 

Static Private Member Functions

void QActive_publish_ (QEvt const *const e, void const *const sender, uint_fast8_t const qsId)
 

Private Attributes

QActiveQActive_registry_ [QF_MAX_ACTIVE+1U]
 
QSubscrListQActive_subscrList_
 
enum_t QActive_maxPubSignal_
 

Detailed Description

Active object class (based on the QHsm implementation strategy)

Description
Active objects are encapsulated tasks (each containing an event queue and a state machine) that communicate with one another asynchronously by sending and receiving events. Within an active object, events are processed in a run-to-completion (RTC) fashion, while QF encapsulates all the details of thread-safe event exchange and queuing.

QActive represents an active object that uses the QHsm-style implementation strategy for state machines. This strategy is tailored to manual coding, but it is also supported by the QM modeling tool. The resulting code is slower than in the QMsm-style implementation strategy.

Note
QActive is not intended to be instantiated directly, but rather serves as the abstract base class for derivation of active objects in the applications.
See also
QMActive
Traceability
Usage
The following example illustrates how to derive an active object from QActive.
typedef struct {
QActive super; // inherit QActive
QTimeEvt timeEvt; // to timeout the blinking
} Blinky;
. . .
void Blinky_ctor(Blinky * const me) {
// constructor of the superclass <---
QActive_ctor(&me->super, Q_STATE_CAST(&Blinky_initial));
// constructor(s) of the members
QTimeEvt_ctorX(&me->timeEvt, &me->super, TIMEOUT_SIG, 0U);
}
#define Q_STATE_CAST(handler_)
Definition qp.h:526
Active object class (based on the QHsm implementation strategy)
Definition qp.h:800
void QActive_ctor(QActive *const me, QStateHandler const initial)
QAsm super
Definition qp.h:802
Time Event class.
Definition qp.h:969

Definition at line 800 of file qp.h.

Member Function Documentation

◆ QActive_ctor()

QActive::QActive_ctor ( QActive *const  me,
QStateHandler const  initial 
)
protected

QActive constructor (abstract base class)

Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]initialpointer to the top-most initial state-handler function in the derived active object

◆ QActive_setAttr()

QActive::QActive_setAttr ( QActive *const  me,
uint32_t  attr1,
void const *  attr2 
)

Generic setting of additional attributes (defined in some QP ports)

◆ QActive_start_()

QActive::QActive_start_ ( QActive *const  me,
QPrioSpec const  prioSpec,
QEvt const **const  qSto,
uint_fast16_t const  qLen,
void *const  stkSto,
uint_fast16_t const  stkSize,
void const *const  par 
)
private

Starts execution of an active object and registers the object with the framework

Description
Starts execution of the AO and registers the AO with the framework.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]prioSpecpriority specification for the AO (See QPrioSpec)
[in]qStopointer to the storage for the ring buffer of the event queue
[in]qLenlength of the event queue [# QEvt* pointers]
[in]stkStopointer to the stack storage (might be NULL)
[in]stkSizestack size [bytes]
[in]parpointer to an extra parameter (might be NULL)
Traceability
Usage
The following example shows starting an AO when a per-task stack is needed:
#include "qpc.h"
int main() {
QF_init(); // initialize the framework and the underlying RT kernel
BSP_init(); // initialize the Board Support Package
. . .
// instantiate and start the active objects...
Blinky_ctor();
static QEvt const *l_blinkyQSto[10]; // Event queue storage for Blinky
QACTIVE_START(AO_Blinky, // AO pointer to start
1U, // unique QP priority of the AO
l_blinkyQSto, // storage for the AO's queue
Q_DIM(l_blinkyQSto), // length of the queue [entries]
(void *)0, // stack storage (not used in QK)
0U, // stack size [bytes] (not used in QK)
(void *)0); // initialization parameter (or 0)
. . .
return QF_run(); // run the QF application
}
#define QACTIVE_START(me_, prioSpec_, qSto_, qLen_, stkSto_, stkSize_, par_)
Definition qp.h:1197
#define Q_DIM(array_)
Definition qp.h:535
QP/C interface including the backwards-compatibility layer.
int_t QF_run(void)
Definition qutest.c:191
void QF_init(void)
Definition qutest.c:172
Event class.
Definition qp.h:147

Definition at line 440 of file qk.c.

◆ QActive_stop()

QActive::QActive_stop ( QActive *const  me)
protected

Stops execution of an active object and removes it from the framework's supervision

Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
Attention
QActive_stop() must be called only from the AO that is about to stop its execution. By that time, any pointers or references to the AO are considered invalid (dangling) and it becomes illegal for the rest of the application to post events to the AO.

Definition at line 242 of file qutest.c.

◆ QActive_register_()

QActive::QActive_register_ ( QActive *const  me)
private

Register this active object to be managed by the framework

Description
This function adds a given active object to the active objects managed by the QF framework. It should not be called by the application directly, only through the function QActive::start().
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
Precondition qf_qact:100
  • the "QF-priority" of the AO must be in range (must be set before calling QActive_register_())
  • the "QF-priority" must not be already in use (unique priority)
  • the "QF-priority" must not exceed the "preemption-threshold"
Postcondition qf_qact:190
  • the preceding pre-thre must not exceed the preemption-threshold
  • the preemption-threshold must not exceed the next preemption-threshold

Definition at line 99 of file qf_qact.c.

◆ QActive_unregister_()

QActive::QActive_unregister_ ( QActive *const  me)
private

Un-register the active object from the framework

Description
This function un-registers a given active object from the active objects managed by the QF framework. It should not be called by the QP ports.
Parameters
[in]mepointer to the active object to remove from the framework.
Precondition qf_qact:200
  • the priority of the active object must not be zero and cannot exceed the maximum QF_MAX_ACTIVE
  • the priority of the AO must be already registered.
Note
The active object that is removed from the framework can no longer participate in any event exchange.

Definition at line 151 of file qf_qact.c.

◆ QActive_post_()

QActive::QActive_post_ ( QActive *const  me,
QEvt const *const  e,
uint_fast16_t const  margin,
void const *const  sender 
)
private

Posts an event e directly to the event queue of the active object using the First-In-First-Out (FIFO) policy.

Description
Direct event posting is the simplest asynchronous communication method available in QF.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]epointer to the event to be posted
[in]marginnumber of required free slots in the queue after posting the event or QF_NO_MARGIN.
[in]senderpointer to a sender object (used in QS only)
Returns
'true' (success) if the posting succeeded (with the provided margin) and 'false' (failure) when the posting fails.
Precondition qf_actq:102
  • the event pointer must be valid
  • check internal event integrity (QP FuSa Subsystem)
Postcondition qf_actq:190
Attention
For margin == QF_NO_MARGIN, this function will assert internally if the event posting fails. In that case, it is unnecessary to check the return value from this function.
Note
This function might be implemented differently in various QP/C ports. The provided implementation assumes that the QEQueue class is used for the QActive event queue.
Traceability
Usage
extern QActive * const AO_Table;
QState Philoso_hungry(Philo * const me, QEvt const * const e) {
QState status;
switch (e->sig) {
case Q_ENTRY_SIG: {
TableEvt *pe = Q_NEW(TableEvt, HUNGRY_SIG); // dynamic alloc
pe->philNum = me->num;
QACTIVE_POST(AO_Table, &pe->super, me); // <===
status = Q_HANDLED();
break;
}
. . .
default: {
status = Q_SUPER(&QHsm_top);
break;
}
}
return status;
}
#define Q_HANDLED()
Definition qp.h:514
#define Q_NEW(evtT_, sig_,...)
Definition qp.h:1167
@ Q_ENTRY_SIG
signal for coding entry actions
Definition qp.h:257
#define QACTIVE_POST(me_, e_, sender_)
Definition qp.h:1203
enum QStateRet QState
Definition qp.h:223
#define Q_SUPER(super_)
Definition qp.h:509
QState QHsm_top(QHsm const *const me, QEvt const *const e)
Definition qep_hsm.c:707
QSignal sig
Definition qp.h:151

◆ QActive_postLIFO_()

QActive::QActive_postLIFO_ ( QActive *const  me,
QEvt const *const  e 
)
private

Posts an event e directly to the event queue of the active object using the Last-In-First-Out (LIFO) policy.

Description
The LIFO policy should be used only for self-posting and with caution because it alters order of events in the queue.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]epointer to the event to be posted
Precondition qf_actq:200
  • for the QXK kernel, postLIFO() cannot be called from an extended thread
Precondition qf_actq:201
  • the queue must be able to accept the event (cannot overflow)
Traceability
Note
This function might be implemented differently in various QP/C ports. The provided implementation assumes that the QEQueue class is used for the QActive event queue.
See also
QActive_post()

Definition at line 215 of file qf_actq.c.

◆ QActive_get_()

QActive::QActive_get_ ( QActive *const  me)
private

Get an event from the event queue of an active object

Description
The behavior of this function depends on the kernel used in the QF port. For built-in kernels (Vanilla or QK) the function can be called only when the queue is not empty, so it doesn't block. For a blocking kernel/OS the function can block and wait for delivery of an event.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
Returns
A pointer to the received event. The returned pointer is guaranteed to be valid (can't be NULL).
Note
This function might be implemented differently in various QP/C ports. The provided implementation assumes that the QEQueue class is used for the QActive event queue.

Definition at line 301 of file qf_actq.c.

◆ QActive_psInit()

QActive::QActive_psInit ( QSubscrList *const  subscrSto,
enum_t const  maxSignal 
)
static

Publish event to all subscribers of a given signal e->sig

Description
This function posts (using the FIFO policy) the event e to all active objects that have subscribed to the signal e->sig, which is called multicasting. The multicasting performed in this function is very efficient based on reference-counting inside the published event ("zero-copy" event multicasting). This function is designed to be callable from any part of the system, including ISRs, device drivers, and active objects.
Note
To avoid any unexpected re-ordering of events posted into AO queues, the event multicasting is performed with scheduler locked. However, the scheduler is locked only up to the priority level of the highest-priority subscriber, so any AOs of even higher priority, which did not subscribe to this event are not affected.

◆ QActive_publish_()

QActive::QActive_publish_ ( QEvt const *const  e,
void const *const  sender,
uint_fast8_t const  qsId 
)
staticprivate

Publish event to all subscribers of a given signal e->sig

Description
This function posts (using the FIFO policy) the event e to all active objects that have subscribed to the signal e->sig, which is called multicasting. The multicasting performed in this function is very efficient based on reference-counting inside the published event ("zero-copy" event multicasting). This function is designed to be callable from any part of the system, including ISRs, device drivers, and active objects.
Precondition qf_ps:200
  • the published signal must be within the configured range
Precondition qf_ps:202
  • check the integrity of the subscriber set (QP FuSa Subsystem)
Note
To avoid any unexpected re-ordering of events posted into AO queues, the event multicasting is performed with scheduler locked. However, the scheduler is locked only up to the priority level of the highest-priority subscriber, so any AOs of even higher priority, which did not subscribe to this event are not affected.
Attention
This operation is typically used via macro QACTIVE_PUBLISH(). This is because the last parameter qsId might be defined/provided only in the Spy build configuration (see Q_SPY). The macro ignores the qsId parameter outside the Spy configuration, so the same code builds correctly in all configurations.
Usage
QState Philo_eating(Philo * const me, QEvt const * const e) {
QState status_;
switch (e->sig) {
. . .
case Q_EXIT_SIG: {
TableEvt const *pe = Q_NEW(TableEvt, DONE_SIG, me->id);
QACTIVE_PUBLISH(&me->super, pe, me); // <===
status_ = Q_RET_HANDLED;
break;
}
. . .
}
return status_;
}
@ Q_RET_HANDLED
event handled (internal transition)
Definition qp.h:202
#define QACTIVE_PUBLISH(e_, sender_)
Definition qp.h:1231
@ Q_EXIT_SIG
signal for coding exit actions
Definition qp.h:258

Definition at line 96 of file qf_ps.c.

◆ QActive_subscribe()

QActive::QActive_subscribe ( QActive const *const  me,
enum_t const  sig 
)
protected

Subscribes for delivery of signal sig to the active object

Description
This function is part of the Publish-Subscribe event delivery mechanism available in QF. Subscribing to an event means that the framework will start posting all published events with a given signal sig to the event queue of the active object.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]sigevent signal to subscribe
Precondition qf_ps:300
  • signal must be in range of subscribe scignals
  • subscriber AO priority must be in range
  • the AO must be registered (started)
Precondition qf_ps:302
  • check the integrity of the subscriber set (QP FuSa Subsystem)
Usage
The following example shows how the Table active object subscribes to three signals in the initial transition:
QState Table_initial(Table * const me, QEvt const * const e) {
// subscribe to event signals...
QActive_subscribe(&me->super, (enum_t)HUNGRY_SIG);
QActive_subscribe(&me->super, (enum_t)DONE_SIG);
QActive_subscribe(&me->super, (enum_t)TERMINATE_SIG);
for (uint8_t n = 0U; n < N; ++n) {
me->fork[n] = FREE;
me->isHungry[n] = false;
}
return Q_TRAN(&Table_serving);
}
#define Q_UNUSED_PAR(par_)
Definition qp.h:532
#define Q_TRAN(target_)
Definition qp.h:499
int enum_t
Definition qp.h:109
void QActive_subscribe(QActive const *const me, enum_t const sig)
Definition qf_ps.c:203

Definition at line 203 of file qf_ps.c.

◆ QActive_unsubscribe()

QActive::QActive_unsubscribe ( QActive const *const  me,
enum_t const  sig 
)
protected

Unsubscribes from the delivery of signal sig to the active object

Description
This function is part of the Publish-Subscribe event delivery mechanism available in QF. Un-subscribing from an event means that the framework will stop posting published events with a given signal sig to the event queue of the active object.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]sigevent signal to unsubscribe
Precondition qf_ps:400
  • signal must be in range of subscribe signals
  • subscriber AO priority must be in range
  • the AO must be registered (started)
Precondition qf_ps:402
  • check the integrity of the subscriber set (QP FuSa Subsystem)
Note
Due to the latency of event queues, an active object should NOT assume that a given signal sig will never be dispatched to the state machine of the active object after un-subscribing from that signal. The event might be already in the queue, or just about to be posted and the un-subscribe operation will not flush such events.
Un-subscribing from a signal that has never been subscribed in the first place is considered an error and QF will raise an assertion.

Definition at line 242 of file qf_ps.c.

◆ QActive_unsubscribeAll()

QActive::QActive_unsubscribeAll ( QActive const *const  me)
protected

Unsubscribes from the delivery of all signals to the active object

Description
This function is part of the Publish-Subscribe event delivery mechanism available in QF. Un-subscribing from all events means that the framework will stop posting any published events to the event queue of the active object.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
Precondition qf_ps:500
  • subscriber AO priority must be in range
  • the AO must be registered (started)
Note
Due to the latency of event queues, an active object should NOT assume that no events will ever be dispatched to the state machine of the active object after un-subscribing from all events. The events might be already in the queue, or just about to be posted and the un-subscribe operation will not flush such events. Also, the alternative event-delivery mechanisms, such as direct event posting or time events, can be still delivered to the event queue of the active object.

Definition at line 281 of file qf_ps.c.

◆ QActive_defer()

QActive::QActive_defer ( QActive const *const  me,
struct QEQueue *const  eq,
QEvt const *const  e 
)
protected

Defer an event to a given separate event queue

Description
This function is part of the event deferral support. An active object uses this function to defer an event e to the QF-supported native event queue eq. QF correctly accounts for another outstanding reference to the event and will not recycle the event at the end of the RTC step. Later, the active object might recall one event at a time from the event queue.
Remarks
An active object can use multiple event queues to defer events of different kinds.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]eqpointer to a "raw" thread-safe queue to recall an event from.
[in]epointer to the event to be deferred
Returns
'true' (success) when the event could be deferred and 'false' (failure) if event deferral failed due to overflowing the queue.

◆ QActive_recall()

QActive::QActive_recall ( QActive *const  me,
struct QEQueue *const  eq 
)
protected

Recall a deferred event from a given event queue

Description
This function is part of the event deferral support. An active object uses this function to recall a deferred event from a given QF event queue. Recalling an event means that it is removed from the deferred event queue eq and posted (LIFO) to the event queue of the active object.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]eqpointer to a "raw" thread-safe queue to recall an event from.
Returns
'true' if an event has been recalled and 'false' if not.
Note
An active object can use multiple event queues to defer events of different kinds.

Definition at line 93 of file qf_defer.c.

◆ QActive_flushDeferred()

QActive::QActive_flushDeferred ( QActive const *const  me,
struct QEQueue *const  eq,
uint_fast16_t const  num 
)
protected

Flush the specified number of events from the deferred queue eq

Description
This function is part of the event deferral support. An active object can use this function to flush a given QF event queue. The function makes sure that the events are not leaked.
Parameters
[in,out]mecurrent instance pointer (see Object Orientation)
[in]eqpointer to a "raw" thread-safe queue to flush.
[in]numnumber of events to flush (note can be a big number, like 0xFFFFU to flush all events)
Returns
the number of events actually flushed from the queue.

Definition at line 154 of file qf_defer.c.

◆ QActive_evtLoop_()

QActive::QActive_evtLoop_ ( QActive *const  me)
private

Event loop thread routine for executing an active object act (defined some in QP ports)

Member Data Documentation

◆ super

QAsm QActive::super

Definition at line 802 of file qp.h.

◆ prio

QActive::prio
protected

QF-priority [1..QF_MAX_ACTIVE] of this AO.

See also
QPrioSpec

Definition at line 805 of file qp.h.

◆ pthre

QActive::pthre
protected

Preemption-threshold [1..QF_MAX_ACTIVE] of this AO.

See also
QPrioSpec

Definition at line 808 of file qp.h.

◆ thread

QActive::thread
protected

Port-dependent representation of the thread of the active object

Description
This data might be used in various ways, depending on the QF port. In some ports me->thread is used store the thread handle. In other ports me->thread can be a pointer to the Thread-Local-Storage (TLS).

Definition at line 812 of file qp.h.

◆ osObject

QActive::osObject
protected

Port-dependent per-thread object.

Description
This data might be used in various ways, depending on the QF port. In some ports me->osObject is used to block the calling thread when the native QF queue is empty. In other QF ports the OS-dependent object might be used differently.

Definition at line 817 of file qp.h.

◆ eQueue

QActive::eQueue
protected

Port-dependent event-queue type (often QEQueue)

Description
The type of the queue depends on the underlying operating system or a kernel. Many kernels support "message queues" that can be adapted to deliver QF events to the active object. Alternatively, QF provides a native event queue implementation that can be used as well.
Note
The native QF event queue is configured by defining the macro QACTIVE_EQUEUE_TYPE as QEQueue.

Definition at line 822 of file qp.h.

◆ prio_dis

uint8_t prio_dis
protected

Definition at line 827 of file qp.h.

◆ pthre_dis

uint8_t pthre_dis
protected

Definition at line 832 of file qp.h.

◆ QActive_registry_

QActive::QActive_registry_
private

Static (one per-class) array of registered active objects

Definition at line 839 of file qp.h.

◆ QActive_subscrList_

QActive::QActive_subscrList_
private

Static (one per-class) pointer to all subscriber AOs for a given event signal.

Definition at line 842 of file qp.h.

◆ QActive_maxPubSignal_

QActive::QActive_maxPubSignal_
private

Static (one per-class) maximum published signal (the size of the subscrList_ array)

Definition at line 845 of file qp.h.


The documentation for this class was generated from the following files: