StreamGroup< Proxy > Class Template Reference

#include <ImFusion/Stream/StreamGroup.h>

Templated stream group class to extend a proxy stream to a StreamGroup with the CRTP pattern. More...

Inheritance diagram for StreamGroup< Proxy >:

Detailed Description

template<class Proxy>
class ImFusion::StreamGroup< Proxy >

Templated stream group class to extend a proxy stream to a StreamGroup with the CRTP pattern.

The proxy stream can be any class deriving from Stream (e.g., ImageStream, TrackingStream, etc.) or Stream itself. The StreamGroup handles an arbitrary set of Substream#s implementing the SubstreamBase interface, whereby the proxy stream owns and controls the substreams and may serve as representative of all streams. Substreams can be added, removed or moved at any time after construction.

Example implementation for a tracking stream with two image streams as substreams

class ExampleStreamGroup : public TrackingStream, public StreamGroup<ExampleStreamGroup>
{
    ExampleStreamGroup::ExampleStreamGroup()
        : TrackingStream("Example Tracking Proxy Stream")
    {
        addSubstream(std::make_unique<ImageSubstream>(this, "Example Image Substream (1)"));
        addSubstream(std::make_unique<ImageSubstream>(this, "Example Image Substream (2)"));
    }
}

See also

Substream, SubstreamWrapper

Public Member Functions
	StreamGroup (StreamGroup &&) noexcept
StreamGroup &	operator= (StreamGroup &&other) noexcept
Stream *	proxyStream () override
	Convenience method to cast the stream group to the proxy stream.
DataList	children () const override
	Returns substreams as a non-owning data list implementing the CompoundData interface.
std::vector< Stream * >	substreams () const override
	Returns the substreams.
Public Member Functions inherited from SignalReceiver
	SignalReceiver ()=default
	Default constructor.
	SignalReceiver (const SignalReceiver &other)
	Copy constructor, does not copy any existing signal connections from other.
SignalReceiver &	operator= (SignalReceiver rhs)
	Assignment operator, disconnects all existing connections, does not copy any existing signal connections from rhs.
virtual	~SignalReceiver ()
	Virtual destructor disconnects from all connected signals.

Protected Member Functions
bool	addSubstream (std::unique_ptr< SubstreamBase > substream) override
	Adds a substream to the stream group.
bool	removeSubstream (Stream *substream) override
	Removes a substream from the stream group.
void	emitMainAndSubSignals (std::shared_ptr< const CompoundStreamData > tuple, bool emitSubstreamSignals=true)
Protected Member Functions inherited from StreamGroupBase
void	reassignSubstream (SubstreamBase *substream)
	Reassigns child to this (needed for move operator)
Protected Member Functions inherited from NotCopyable
	NotCopyable (NotCopyable &&) noexcept=default
NotCopyable &	operator= (NotCopyable &&) noexcept=default
	NotCopyable (const NotCopyable &)=delete
NotCopyable &	operator= (const NotCopyable &)=delete
Protected Member Functions inherited from SignalReceiver
void	disconnectAll ()
	Disconnects all existing connections.

Additional Inherited Members
Public Attributes inherited from StreamGroupBase
ProtectedSignal< std::shared_ptr< const CompoundStreamData > >	signalNewStreamGroupData
	Signal contains all StreamData from the substreams.
Public Attributes inherited from CompoundData
Signal< Data * >	signalChildAdded
	Signal emitted when a new Data instance has been added to children()
Signal< Data * >	signalChildMoved
	Signal emitted when a Data instance has changed its position in children()
Signal< Data * >	signalChildAboutToBeRemoved
	Signal emitted when a Data instance is about to be removed or taken from children()

Member Function Documentation

proxyStream()

template<class Proxy>

Stream * proxyStream ( )

overridevirtual

Convenience method to cast the stream group to the proxy stream.

Implements StreamGroupBase.

children()

template<class Proxy>

DataList children ( ) const

overridevirtual

Returns substreams as a non-owning data list implementing the CompoundData interface.

See the documentation of substreams for details on thread safety.

See also

CompoundData

Implements CompoundData.

substreams()

template<class Proxy>

std::vector< Stream * > substreams ( ) const

overridevirtual

Returns the substreams.

It is guaranteed that the substreams are not deleted within a doWork call until emitMainAndSubSignals has finished, even if some of the substreams are removed from the substream list already during the method execution. The following code is fully safe:

doWork()
{
    auto streams = substreams();  // Get a local copy of the substreams
    // Here, another thread might remove a substream and the local copy is outdated: streams != substreams()
    for (auto& s : streams())
    {
        // Do stuff with all the streams to prepare stream data.
    }
 
    CompoundStreamData sdt(proxyStreamData, streamData);
    emitMainAndSubSignals(sdt);   // The actual deletion of the removed substream occurs at the end of this call.
 
    return WorkContinuation{nextIterationTime};
}

Implements StreamGroupBase.

addSubstream()

template<class Proxy>

bool addSubstream ( std::unique_ptr< SubstreamBase > substream )

overrideprotectedvirtual

Adds a substream to the stream group.

Implements StreamGroupBase.

removeSubstream()

template<class Proxy>

bool removeSubstream ( Stream * substream )

overrideprotectedvirtual

Removes a substream from the stream group.

The removal is always executed on the main thread since the data model cannot handle removal calls from any other thread. If this method is called on another thread the actual removal is invoked on the main thread.

Implements StreamGroupBase.

---

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

• ImFusion/Stream/StreamGroup.h