vtkThreadedCallbackQueue Class Reference

simple threaded callback queue More...

#include <vtkThreadedCallbackQueue.h>

Inheritance diagram for vtkThreadedCallbackQueue:

Collaboration diagram for vtkThreadedCallbackQueue:

Classes
class	vtkSharedFuture
	A vtkSharedFuture is an object returned by the methods Push and PushDependent. More...
class	vtkSharedFutureBase
	vtkSharedFutureBase is the base block to store, run, get the returned value of the tasks that are pushed in the queue. More...

Public Types
typedef vtkObject	Superclass
using	SharedFutureBasePointer = vtkSmartPointer< vtkSharedFutureBase >
template<class ReturnT >
using	SharedFuturePointer = vtkSmartPointer< vtkSharedFuture< ReturnT > >

Public Member Functions
virtual vtkTypeBool	IsA (const char *type)
	Return 1 if this class is the same type of (or a subclass of) the named class.
vtkThreadedCallbackQueue *	NewInstance () const
void	PrintSelf (ostream &os, vtkIndent indent) override
	Methods invoked by print to print information about the object including superclasses.
	vtkThreadedCallbackQueue ()
	~vtkThreadedCallbackQueue () override
	Any remaining function that was not executed yet will be executed in this destructor.
template<class FT , class... ArgsT>
SharedFuturePointer< InvokeResult< FT > >	Push (FT &&f, ArgsT &&... args)
	Pushes a function f to be passed args... as arguments.
template<class SharedFutureContainerT , class FT , class... ArgsT>
SharedFuturePointer< InvokeResult< FT > >	PushDependent (SharedFutureContainerT &&priorSharedFutures, FT &&f, ArgsT &&... args)
	This method behaves the same way Push does, with the addition of a container of futures.
template<class SharedFutureContainerT >
void	Wait (SharedFutureContainerT &&priorSharedFuture)
	This method blocks the current thread until all the tasks associated with each shared future inside priorSharedFuture has terminated.
void	SetNumberOfThreads (int numberOfThreads)
	Sets the number of threads.
int	GetNumberOfThreads () const
	Returns the number of allocated threads.
template<class ReturnT >
vtkSharedFuture< ReturnT >::ReturnLValueRef	Get (SharedFuturePointer< ReturnT > &future)
	Get the returned value from the task associated with the input future.
template<class ReturnT >
vtkSharedFuture< ReturnT >::ReturnConstLValueRef	Get (const SharedFuturePointer< ReturnT > &future)
	Get the returned value from the task associated with the input future.
Public Member Functions inherited from vtkObject
	vtkBaseTypeMacro (vtkObject, vtkObjectBase)
virtual void	DebugOn ()
	Turn debugging output on.
virtual void	DebugOff ()
	Turn debugging output off.
bool	GetDebug ()
	Get the value of the debug flag.
void	SetDebug (bool debugFlag)
	Set the value of the debug flag.
virtual void	Modified ()
	Update the modification time for this object.
virtual vtkMTimeType	GetMTime ()
	Return this object's modified time.
void	PrintSelf (ostream &os, vtkIndent indent) override
	Methods invoked by print to print information about the object including superclasses.
void	RemoveObserver (unsigned long tag)
void	RemoveObservers (unsigned long event)
void	RemoveObservers (const char *event)
void	RemoveAllObservers ()
vtkTypeBool	HasObserver (unsigned long event)
vtkTypeBool	HasObserver (const char *event)
vtkTypeBool	InvokeEvent (unsigned long event)
vtkTypeBool	InvokeEvent (const char *event)
std::string	GetObjectDescription () const override
	The object description printed in messages and PrintSelf output.
unsigned long	AddObserver (unsigned long event, vtkCommand *, float priority=0.0f)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
unsigned long	AddObserver (const char *event, vtkCommand *, float priority=0.0f)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkCommand *	GetCommand (unsigned long tag)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObserver (vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObservers (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObservers (const char *event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkTypeBool	HasObserver (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkTypeBool	HasObserver (const char *event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f)
	Overloads to AddObserver that allow developers to add class member functions as callbacks for events.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
	Overloads to AddObserver that allow developers to add class member functions as callbacks for events.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, bool(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
	Allow user to set the AbortFlagOn() with the return value of the callback method.
vtkTypeBool	InvokeEvent (unsigned long event, void *callData)
	This method invokes an event and return whether the event was aborted or not.
vtkTypeBool	InvokeEvent (const char *event, void *callData)
	This method invokes an event and return whether the event was aborted or not.
virtual void	SetObjectName (const std::string &objectName)
	Set/get the name of this object for reporting purposes.
virtual std::string	GetObjectName () const
	Set/get the name of this object for reporting purposes.
Public Member Functions inherited from vtkObjectBase
const char *	GetClassName () const
	Return the class name as a string.
virtual std::string	GetObjectDescription () const
	The object description printed in messages and PrintSelf output.
virtual vtkTypeBool	IsA (const char *name)
	Return 1 if this class is the same type of (or a subclass of) the named class.
virtual vtkIdType	GetNumberOfGenerationsFromBase (const char *name)
	Given the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class).
virtual void	Delete ()
	Delete a VTK object.
virtual void	FastDelete ()
	Delete a reference to this object.
void	InitializeObjectBase ()
void	Print (ostream &os)
	Print an object to an ostream.
void	Register (vtkObjectBase *o)
	Increase the reference count (mark as used by another object).
virtual void	UnRegister (vtkObjectBase *o)
	Decrease the reference count (release by another object).
int	GetReferenceCount ()
	Return the current reference count of this object.
void	SetReferenceCount (int)
	Sets the reference count.
bool	GetIsInMemkind () const
	A local state flag that remembers whether this object lives in the normal or extended memory space.
virtual void	PrintHeader (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses.
virtual void	PrintTrailer (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses.
virtual bool	UsesGarbageCollector () const
	Indicate whether the class uses vtkGarbageCollector or not.

Static Public Member Functions
static vtkThreadedCallbackQueue *	New ()
static vtkTypeBool	IsTypeOf (const char *type)
static vtkThreadedCallbackQueue *	SafeDownCast (vtkObjectBase *o)
Static Public Member Functions inherited from vtkObject
static vtkObject *	New ()
	Create an object with Debug turned off, modified time initialized to zero, and reference counting on.
static void	BreakOnError ()
	This method is called when vtkErrorMacro executes.
static void	SetGlobalWarningDisplay (vtkTypeBool val)
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static void	GlobalWarningDisplayOn ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static void	GlobalWarningDisplayOff ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static vtkTypeBool	GetGlobalWarningDisplay ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
Static Public Member Functions inherited from vtkObjectBase
static vtkTypeBool	IsTypeOf (const char *name)
	Return 1 if this class type is the same type of (or a subclass of) the named class.
static vtkIdType	GetNumberOfGenerationsFromBaseType (const char *name)
	Given a the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class).
static vtkObjectBase *	New ()
	Create an object with Debug turned off, modified time initialized to zero, and reference counting on.
static void	SetMemkindDirectory (const char *directoryname)
	The name of a directory, ideally mounted -o dax, to memory map an extended memory space within.
static bool	GetUsingMemkind ()
	A global state flag that controls whether vtkObjects are constructed in the usual way (the default) or within the extended memory space.

Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const
Protected Member Functions inherited from vtkObject
	vtkObject ()
	~vtkObject () override
void	RegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void	UnRegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void	InternalGrabFocus (vtkCommand *mouseEvents, vtkCommand *keypressEvents=nullptr)
	These methods allow a command to exclusively grab all events.
void	InternalReleaseFocus ()
	These methods allow a command to exclusively grab all events.
Protected Member Functions inherited from vtkObjectBase
	vtkObjectBase ()
virtual	~vtkObjectBase ()
virtual void	RegisterInternal (vtkObjectBase *, vtkTypeBool check)
virtual void	UnRegisterInternal (vtkObjectBase *, vtkTypeBool check)
virtual void	ReportReferences (vtkGarbageCollector *)
virtual void	ObjectFinalize ()
	vtkObjectBase (const vtkObjectBase &)
void	operator= (const vtkObjectBase &)

Friends
class	ThreadWorker

Additional Inherited Members
Static Protected Member Functions inherited from vtkObjectBase
static vtkMallocingFunction	GetCurrentMallocFunction ()
static vtkReallocingFunction	GetCurrentReallocFunction ()
static vtkFreeingFunction	GetCurrentFreeFunction ()
static vtkFreeingFunction	GetAlternateFreeFunction ()
Protected Attributes inherited from vtkObject
bool	Debug
vtkTimeStamp	MTime
vtkSubjectHelper *	SubjectHelper
std::string	ObjectName
Protected Attributes inherited from vtkObjectBase
std::atomic< int32_t >	ReferenceCount
vtkWeakPointerBase **	WeakPointers

Detailed Description

simple threaded callback queue

This callback queue executes pushed functions and functors on threads whose purpose is to execute those functions. By default, one thread is created by this class, so it is advised to set NumberOfThreads. Upon destruction of an instance of this callback queue, remaining unexecuted threads are executed.

When a task is pushed, a vtkSharedFuture is returned. This instance can be used to get the returned value when the task is finished, and provides functionalities to synchronize the main thread with the status of its associated task.

All public methods of this class are thread safe.

Tests:

vtkThreadedCallbackQueue (Tests)

Definition at line 45 of file vtkThreadedCallbackQueue.h.

Member Typedef Documentation

Superclass

typedef vtkObject vtkThreadedCallbackQueue::Superclass

Definition at line 88 of file vtkThreadedCallbackQueue.h.

SharedFutureBasePointer

using vtkThreadedCallbackQueue::SharedFutureBasePointer = vtkSmartPointer<vtkSharedFutureBase>

Definition at line 210 of file vtkThreadedCallbackQueue.h.

SharedFuturePointer

template<class ReturnT >

using vtkThreadedCallbackQueue::SharedFuturePointer = vtkSmartPointer<vtkSharedFuture<ReturnT> >

Definition at line 212 of file vtkThreadedCallbackQueue.h.

Constructor & Destructor Documentation

vtkThreadedCallbackQueue()

vtkThreadedCallbackQueue::vtkThreadedCallbackQueue

(

)

~vtkThreadedCallbackQueue()

vtkThreadedCallbackQueue::~vtkThreadedCallbackQueue ( )

override

Any remaining function that was not executed yet will be executed in this destructor.

Member Function Documentation

New()

static vtkThreadedCallbackQueue * vtkThreadedCallbackQueue::New ( )

static

IsTypeOf()

static vtkTypeBool vtkThreadedCallbackQueue::IsTypeOf ( const char *  type )

static

IsA()

virtual vtkTypeBool vtkThreadedCallbackQueue::IsA ( const char *  name )

virtual

Return 1 if this class is the same type of (or a subclass of) the named class.

Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkObjectBase.

SafeDownCast()

static vtkThreadedCallbackQueue * vtkThreadedCallbackQueue::SafeDownCast ( vtkObjectBase *  o )

static

NewInstanceInternal()

virtual vtkObjectBase * vtkThreadedCallbackQueue::NewInstanceInternal ( ) const

protectedvirtual

NewInstance()

vtkThreadedCallbackQueue * vtkThreadedCallbackQueue::NewInstance

(

)

const

PrintSelf()

void vtkThreadedCallbackQueue::PrintSelf ( ostream &  os, vtkIndent  indent  )

overridevirtual

Methods invoked by print to print information about the object including superclasses.

Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkObject.

Push()

template<class FT , class... ArgsT>

SharedFuturePointer< InvokeResult< FT > > vtkThreadedCallbackQueue::Push	(	FT &&	f,
		ArgsT &&...	args
	)

Pushes a function f to be passed args... as arguments.

f will be called as soon as a running thread has the occasion to do so, in a FIFO fashion. This method returns a vtkSharedFuture, which is an object allowing to synchronize the code.

All the arguments of Push are stored persistently inside the queue. An argument passed as an lvalue reference will trigger a copy constructor call. It is thus advised, when possible, to pass rvalue references or smart pointers (vtkSmartPointer or std::shared_ptr for example)

The input function can be a pointer function, a lambda expression, a std::function a functor or a member function pointer.

If f is a functor, its copy constructor will be invoked if it is passed as an lvalue reference. Consequently, if the functor is somewhat heavy, it is advised to pass it as an rvalue reference or to wrap inside a smart pointer (std::unique_ptr for example).

If f is a member function pointer, an instance of its host class needs to be provided in the second parameter. Similar to the functor case, it is advised in order to avoid calling the copy constructor to pass it as an rvalue reference or to wrap it inside a smart pointer.

Below is a short example showing off different possible insertions to this queue:

struct S {
 void operator()(int) {}
 void f() {}
 void f_const() {}
};
void f(S&&, const S&) {}
 
vtkNew<vtkThreadedCallbackQueue> queue;
int x;
S s;
 
// Pushing a lambda expression.
queue->Push([]{});
 
// Pushing a function pointer
// Note that the copy constructor is called for s
queue->Push(&f, s, S());
 
// Pushing a functor.
queue->Push(S(), x);
 
// Pushing a functor wrapped inside a smart pointer.
queue->Push(std::unique_ptr<S>(new S()), x);
 
// Pushing a member function pointer.
// Don't forget to pass an instance of the host class.
queue->Push(&S::f, S());
 
// Pushing a const member function pointer.
// This time, we wrap the instance of the host class inside a smart pointer.
queue->Push(&S::f_const, std::unique_ptr<S>(new S()));

Warning

DO NOT capture lvalue references in a lambda expression pushed into the queue unless you can ensure that the function will be executed in the same scope where the input lives. If not, such captures may be destroyed before the lambda is invoked by the queue.

PushDependent()

template<class SharedFutureContainerT , class FT , class... ArgsT>

SharedFuturePointer< InvokeResult< FT > > vtkThreadedCallbackQueue::PushDependent	(	SharedFutureContainerT &&	priorSharedFutures,
		FT &&	f,
		ArgsT &&...	args
	)

This method behaves the same way Push does, with the addition of a container of futures.

The function to be pushed will not be executed until the functions associated with the input futures have terminated.

The container of futures must have forward iterator (presence of a begin() and end() member function).

Wait()

template<class SharedFutureContainerT >

void vtkThreadedCallbackQueue::Wait

(

SharedFutureContainerT &&

priorSharedFuture

)

This method blocks the current thread until all the tasks associated with each shared future inside priorSharedFuture has terminated.

It is in general more efficient to call this function than to call Wait on each future individually because if any task associated with priorSharedFuture is allowed to run (i.e. it is not depending on any other future) and is currently waiting in queue, this function will actually run it.

The current thread is blocked at most once by this function.

SharedFutureContainerT must have a forward iterator (presence of a begin() and end() member function).

Get() [1/2]

template<class ReturnT >

vtkSharedFuture< ReturnT >::ReturnLValueRef vtkThreadedCallbackQueue::Get

(

SharedFuturePointer< ReturnT > &

future

)

Get the returned value from the task associated with the input future.

It effectlively calls Wait. If the task has not started yet upon the call of this function, then the current thread will run the task itself.

This function returns void if ReturnT is void. It returns ReturnT& or const ReturnT& otherwise.

Get() [2/2]

template<class ReturnT >

vtkSharedFuture< ReturnT >::ReturnConstLValueRef vtkThreadedCallbackQueue::Get

(

const SharedFuturePointer< ReturnT > &

future

)

Get the returned value from the task associated with the input future.

It effectlively calls Wait. If the task has not started yet upon the call of this function, then the current thread will run the task itself.

This function returns void if ReturnT is void. It returns ReturnT& or const ReturnT& otherwise.

SetNumberOfThreads()

void vtkThreadedCallbackQueue::SetNumberOfThreads

(

int

numberOfThreads

)

Sets the number of threads.

The running state of the queue is not impacted by this method.

This method is executed by the Controller on a different thread, so this method may terminate before the threads were allocated. Nevertheless, this method is thread-safe. Other calls to SetNumberOfThreads() will be queued by the Controller, which executes all received command serially in the background.

GetNumberOfThreads()

int vtkThreadedCallbackQueue::GetNumberOfThreads ( ) const

inline

Returns the number of allocated threads.

Note that this method doesn't give any information on whether threads are running or not.

Note

SetNumberOfThreads(int) runs in the background. So the number of threads of this queue might change asynchronously as those commands are executed.

Definition at line 340 of file vtkThreadedCallbackQueue.h.

Friends And Related Symbol Documentation

ThreadWorker

friend class ThreadWorker

friend

Definition at line 359 of file vtkThreadedCallbackQueue.h.

---

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

• Common/Core/vtkThreadedCallbackQueue.h