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microbit: Added support to remove MicroBitListener event handlers.

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This commit is contained in:
Joe Finney 2015-09-10 12:53:39 +01:00
parent 8ea2e953c8
commit 51493092ff
6 changed files with 253 additions and 18 deletions
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2
inc/MemberFunctionCallback.h
View file

@ -53,7 +53,7 @@ template <typename T>
MemberFunctionCallback::MemberFunctionCallback(T* object, void (T::*method)(MicroBitEvent e))
{
this->object = object;
memclr(this->method, sizeof(method));
memclr(this->method, sizeof(this->method));
memcpy(this->method, &method, sizeof(method));
invoke = &MemberFunctionCallback::methodCall<T>;
}

5
inc/MicroBitListener.h
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@ -54,6 +54,11 @@ struct MicroBitListener
*/
template <typename T>
MicroBitListener(uint16_t id, uint16_t value, T* object, void (T::*method)(MicroBitEvent));
/**
* Destructor. Ensures all resources used by this listener are freed.
*/
~MicroBitListener();
};
/**

139
inc/MicroBitMessageBus.h
View file

@ -110,20 +110,116 @@ class MicroBitMessageBus : public MicroBitComponent
/**
* Register a listener function.
*
* Same as above, except the listener function is passed an extra argument in addition to the
* MicroBitEvent, when called.
* @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
* Use MICROBIT_ID_ANY to receive events from all components.
*
* @param value The value of messages to listen for. Events with any other values will be filtered.
* Use MICROBIT_EVT_ANY to receive events of any value.
*
* @param hander The function to call when an event is received.
*
* Example:
* @code
* void onButtonBClick(void *arg)
* {
* //do something
* }
* uBit.MessageBus.listen(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); // call function when ever a click event is detected.
* @endcode
*/
void listen(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg);
/**
* Register a listener function.
*
* @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
* Use MICROBIT_ID_ANY to receive events from all components.
*
* @param value The value of messages to listen for. Events with any other values will be filtered.
* Use MICROBIT_EVT_ANY to receive events of any value.
*
* @param hander The function to call when an event is received.
*
* Example:
* @code
* void SomeClass::onButtonBClick()
* {
* //do something
* }
*
* As above, but allows callbacks into member functions within a C++ object.
* This one is a bit more complex, but hey, that's C++ for you!
* SomeClass s = new SomeClass();
* uBit.MessageBus.listen(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick);
* @endcode
*/
template <typename T>
void listen(uint16_t id, uint16_t value, T* object, void (T::*handler)(MicroBitEvent));
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
* void onButtonBClick()
* {
* //do something
* }
*
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
* @endcode
*/
void ignore(int id, int value, void (*handler)(MicroBitEvent));
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
* void onButtonBClick(void *arg)
* {
* //do something
* }
*
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
* @endcode
*/
void ignore(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg);
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
*
* void SomeClass::onButtonBClick()
* {
* //do something
* }
*
* SomeClass s = new SomeClass();
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick);
* @endcode
*/
template <typename T>
void ignore(uint16_t id, uint16_t value, T* object, void (T::*handler)(MicroBitEvent));
private:
/**
@ -132,6 +228,7 @@ class MicroBitMessageBus : public MicroBitComponent
* @return 1 if the listener is valid, 0 otherwise.
*/
int add(MicroBitListener *newListener);
int remove(MicroBitListener *newListener);
MicroBitListener *listeners; // Chain of active listeners.
MicroBitEventQueueItem *evt_queue_head; // Head of queued events to be processed.
@ -166,13 +263,39 @@ void MicroBitMessageBus::listen(uint16_t id, uint16_t value, T* object, void (T:
MicroBitListener *newListener = new MicroBitListener(id, value, object, handler);
if(!add(newListener))
{
delete newListener->cb_method;
delete newListener;
return;
}
}
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
* void onButtonBClick(void *arg)
* {
* //do something
* }
*
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
* @endcode
*/
template <typename T>
void MicroBitMessageBus::ignore(uint16_t id, uint16_t value, T* object, void (T::*handler)(MicroBitEvent))
{
if (handler == NULL)
return;
MicroBitListener listener(id, value, object, handler);
remove(&listener);
}
#endif

3
source/MemberFunctionCallback.cpp
View file

@ -26,7 +26,6 @@ void MemberFunctionCallback::fire(MicroBitEvent e)
*/
bool MemberFunctionCallback::operator==(const MemberFunctionCallback &mfc)
{
return (object == mfc.object && memcmp(method,mfc.method,sizeof(method))==0);
return (object == mfc.object && (memcmp(method,mfc.method,sizeof(method))==0));
}

8
source/MicroBitListener.cpp
View file

@ -43,3 +43,11 @@ MicroBitListener::MicroBitListener(uint16_t id, uint16_t value, void (*handler)(
this->next = NULL;
}
/**
* Destructor. Ensures all resources used by this listener are freed.
*/
MicroBitListener::~MicroBitListener()
{
if(this->flags & MESSAGE_BUS_LISTENER_METHOD)
delete cb_method;
}

114
source/MicroBitMessageBus.cpp
View file

@ -245,10 +245,7 @@ void MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent
MicroBitListener *newListener = new MicroBitListener(id, value, handler);
if(!add(newListener))
{
delete newListener;
return;
}
}
void MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg)
@ -259,10 +256,63 @@ void MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent
MicroBitListener *newListener = new MicroBitListener(id, value, handler, arg);
if(!add(newListener))
{
delete newListener;
return;
}
}
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
* void onButtonBClick()
* {
* //do something
* }
*
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
* @endcode
*/
void MicroBitMessageBus::ignore(int id, int value, void (*handler)(MicroBitEvent))
{
if (handler == NULL)
return;
MicroBitListener listener(id, value, handler);
remove(&listener);
}
/**
* Unregister a listener function.
* Listners are identified by the Event ID, Event VALUE and handler registered using listen().
*
* @param id The Event ID used to register the listener.
* @param value The Event VALUE used to register the listener.
* @param handler The function used to register the listener.
*
*
* Example:
* @code
* void onButtonBClick(void *arg)
* {
* //do something
* }
*
* uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
* @endcode
*/
void MicroBitMessageBus::ignore(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg)
{
if (handler == NULL)
return;
MicroBitListener listener(id, value, handler, arg);
remove(&listener);
}
@ -280,7 +330,6 @@ int MicroBitMessageBus::add(MicroBitListener *newListener)
if (newListener == NULL)
return 0;
methodCallback = newListener->flags & MESSAGE_BUS_LISTENER_METHOD;
l = listeners;
@ -291,6 +340,8 @@ int MicroBitMessageBus::add(MicroBitListener *newListener)
// If we have a callback to a method, check the cb_method class. Otherwise, the cb function point is sufficient.
while (l != NULL)
{
methodCallback = (newListener->flags & MESSAGE_BUS_LISTENER_METHOD) && (l->flags & MESSAGE_BUS_LISTENER_METHOD);
if (l->id == newListener->id && l->value == newListener->value && (methodCallback ? *l->cb_method == *newListener->cb_method : l->cb == newListener->cb))
return 0;
@ -344,3 +395,52 @@ int MicroBitMessageBus::add(MicroBitListener *newListener)
return 1;
}
/**
* Remove a MicroBitListener from the list that matches the given listener.
* @param listener The MicroBitListener to validate.
* @return The number of listeners removed from the list.
*/
int MicroBitMessageBus::remove(MicroBitListener *listener)
{
MicroBitListener *l, *p;
int removed = 0;
//handler can't be NULL!
if (listener == NULL)
return 0;
l = listeners;
p = NULL;
// Walk this list of event handlers. Delete any that match the given listener.
while (l != NULL)
{
if (l->id == listener->id && l->value == listener->value && ((listener->flags & MESSAGE_BUS_LISTENER_METHOD) == (l->flags & MESSAGE_BUS_LISTENER_METHOD)))
{
if(((listener->flags & MESSAGE_BUS_LISTENER_METHOD) && (*l->cb_method == *listener->cb_method)) ||
((!(listener->flags & MESSAGE_BUS_LISTENER_METHOD) && l->cb == listener->cb)))
{
// Found a match. Remove from the list.
if (p == NULL)
listeners = l->next;
else
p->next = l->next;
// delete the listener.
MicroBitListener *t = l;
l = l->next;
delete t;
removed++;
continue;
}
}
p = l;
l = l->next;
}
return removed;
}