Merge branch 'feature/VistaDefaultObserver' into 'develop'

Feature/vista default observer

See merge request !25

VistaCoreLibs/VistaAspects/VistaObserver.cpp

@@ -34,10 +34,6 @@
 /* CONSTRUCTORS / DESTRUCTOR                                                  */
 /*============================================================================*/
 
-
-IVistaObserver::IVistaObserver(IVistaObserver &)
-{}
-
 IVistaObserver::IVistaObserver()
 : m_bObserverEnabled( true )
 { }
@@ -46,16 +42,12 @@ IVistaObserver::~IVistaObserver()
 {
 	// copy vector of observables, because the original (member) version
 	// is altered during the ReleaseObserveable call
-	std::vector<IVistaObserveable *> vecObs = m_vecObserveables;
+	const auto vecObs = m_vecObserveables;
 
-	std::vector<IVistaObserveable *>::iterator it;
-	for (it = vecObs.begin(); it != vecObs.end(); ++it)
+	for( IVistaObserveable* pObs : vecObs )
 	{
-		ReleaseObserveable(*it, IVistaObserveable::TICKET_NONE);
+		ReleaseObserveable( pObs, IVistaObserveable::TICKET_NONE );
 	}
-
-	m_vecObserveables.clear();
-
 }
 
 /*============================================================================*/
@@ -72,29 +64,27 @@ void IVistaObserver::SetIsObserverEnabled(bool bEnabled)
 	m_bObserverEnabled = bEnabled;
 }
 
-void IVistaObserver::UpdateRequest(IVistaObserveable *pObserveable, int msg, int nTicket)
+void IVistaObserver::UpdateRequest( IVistaObserveable* pObserveable,
+									int msg,
+									int nTicket )
 {
 	if( m_bObserverEnabled )
+	{
 		ObserverUpdate( pObserveable, msg, nTicket );
 	}
+}
 
-bool IVistaObserver::ObserveableDeleteRequest(
-	IVistaObserveable* pObserveable, 
-	int nTicket /*= IVistaObserveable::TICKET_NONE */
-	)
+bool IVistaObserver::ObserveableDeleteRequest( IVistaObserveable* pObserveable,
+											   int nTicket )
 {
 	return true;
 }
 
-void IVistaObserver::ObserveableDelete(
-	IVistaObserveable* pObserveable, 
-	int nTicket /*= IVistaObserveable::TICKET_NONE */
-	)
+void IVistaObserver::ObserveableDelete( IVistaObserveable* pObserveable, int nTicket )
 {
-	// just delete pObserveable from list
-
-	std::vector<IVistaObserveable*>::iterator it =
-		std::find(m_vecObserveables.begin(), m_vecObserveables.end(), pObserveable);
+	const auto it = std::find( m_vecObserveables.begin(),
+							   m_vecObserveables.end(),
+							   pObserveable );
 
 	if( it != m_vecObserveables.end() )
 	{
@@ -102,17 +92,15 @@ void IVistaObserver::ObserveableDelete(
 	}
 }
 
-void IVistaObserver::ReleaseObserveable(
-	IVistaObserveable* pObserveable, 
-	int nTicket /*= IVistaObserveable::TICKET_NONE */
-	)
+void IVistaObserver::ReleaseObserveable( IVistaObserveable* pObserveable, int nTicket )
 {
 	if( Observes( pObserveable ) )
 	{
 		pObserveable->DetachObserver( this );
 
-		std::vector<IVistaObserveable*>::iterator it =
-			std::find(m_vecObserveables.begin(), m_vecObserveables.end(), pObserveable);
+		const auto it = std::find( m_vecObserveables.begin(),
+								   m_vecObserveables.end(),
+								   pObserveable );
 
 		if( it != m_vecObserveables.end() )
 		{
@@ -123,25 +111,39 @@ void IVistaObserver::ReleaseObserveable(
 
 bool IVistaObserver::Observes( IVistaObserveable* pObserveable )
 {
-	std::vector<IVistaObserveable *>::iterator it =
-		std::find(m_vecObserveables.begin(), m_vecObserveables.end(), pObserveable);
+	const auto it = std::find( m_vecObserveables.begin(),
+							   m_vecObserveables.end(),
+							   pObserveable );
 
 	return ( it != m_vecObserveables.end() );
 }
 
-void IVistaObserver::Observe(
-	IVistaObserveable* pObserveable, 
-	int nTicket /*= IVistaObserveable::TICKET_NONE */
-	)
+void IVistaObserver::Observe( IVistaObserveable* pObserveable, int nTicket )
 {
-	if (!Observes(pObserveable))
+	if( !Observes( pObserveable ) && pObserveable->AttachObserver( this, nTicket ) )
 	{
-		if (pObserveable->AttachObserver(this, nTicket))
 		m_vecObserveables.push_back( pObserveable );
 	}
 }
 
+
 /*============================================================================*/
-/* LOCAL VARS AND FUNCS                                                       */
+/* DEFAULT OBSERVER IMPLEMENTATION                                            */
 /*============================================================================*/
 
+VistaSimpleObserver::VistaSimpleObserver(
+	std::function< void( IVistaObserveable*, int, int ) > fnObserverUpdate )
+: m_fnObserverUpdate( std::move( fnObserverUpdate ) )
+{ }
+
+void VistaSimpleObserver::ObserverUpdate( IVistaObserveable* pObserveable,
+										  int nMsg,
+										  int nTicket )
+{
+	m_fnObserverUpdate( pObserveable, nMsg, nTicket );
+}
+
+
+/*============================================================================*/
+/* LOCAL VARS AND FUNCS                                                       */
+/*============================================================================*/

VistaCoreLibs/VistaAspects/VistaObserver.h

@@ -34,6 +34,8 @@
 #include "VistaNameable.h"
 #include "VistaObserveable.h"
 
+#include <functional>
+
 
 /*============================================================================*/
 /* MACROS AND DEFINES                                                         */
@@ -59,8 +61,10 @@
 class VISTAASPECTSAPI IVistaObserver
 {
 public:
-	virtual ~IVistaObserver();
+	IVistaObserver( const IVistaObserver& ) = delete;
+	IVistaObserver& operator=( const IVistaObserver& ) = delete;
 
+	virtual ~IVistaObserver();
 	
 	/**
 	 * An observeable is about to be deleted, this can be forbidden by returning
@@ -78,7 +82,6 @@ public:
 	virtual bool ObserveableDeleteRequest( IVistaObserveable* pObserveable,
 										   int nTicket = IVistaObserveable::TICKET_NONE );
 
-
 	/**
 	 * This is sent to the observer before the observeable is deleted. Note that this
 	 * is not a question, but a notification. After this notification passed, the observer
@@ -141,24 +144,37 @@ public:
 
 	bool GetIsObserverEnabled() const;
 	virtual void SetIsObserverEnabled( bool bEnabled );
+
 protected:
 	IVistaObserver();
 
-	// list of objects observed by this observer
-	// Note: this is implemented as a vector (even though we have to perform
-	// operations like deleting arbitrary elements), as this is nevertheless
-	// way faster than on an std::list.
 	std::vector< IVistaObserveable* > m_vecObserveables;
 
 private:
+	bool m_bObserverEnabled;
+};
+
 /**
-	 * Copy-constructor. We prevent copying.
+ * This class facilitates the creation of a very simple observer, i.e., one in
+ * which only the ObserverUpdate function needs to be overridden. For this,
+ * instead of deriving a custom observer type, one can simply forgo this step
+ * and supply a std::function which is called by the update function. Note, that
+ * managing state usually becomes much harder using this implementation.
  */
-	IVistaObserver(IVistaObserver &);
+class VISTAASPECTSAPI VistaSimpleObserver : public IVistaObserver
+{
+public:
+	VistaSimpleObserver(
+		std::function< void( IVistaObserveable*, int, int ) > fnObserverUpdate );
+	~VistaSimpleObserver() override = default;
 
-	bool m_bObserverEnabled;
+	void ObserverUpdate(
+		IVistaObserveable* pObserveable, int nMsg, int nTicket ) override;
 
+private:
+	std::function< void( IVistaObserveable*, int, int ) > m_fnObserverUpdate;
 };
+
 /*============================================================================*/
 /* LOCAL VARS AND FUNCS                                                       */
 /*============================================================================*/