Helper to propagate decoration dependencies to a shallow copy. More...

#include <ShallowCopyDecorDeps.h>

Collaboration diagram for SG::ShallowCopyDecorDeps< T >:

Public Member Functions
template<class OWNER >
	ShallowCopyDecorDeps (OWNER *owner, const std::string &name, std::initializer_list< std::string > l, const std::string &doc="")
	Auto-declaring Property constructor. More...

StatusCode	initialize (const SG::ReadHandleKey< T > &origKey, const SG::WriteHandleKey< T > &copyKey, bool used=true)
	Initialize this property. More...

StatusCode	linkDecors (const SG::ReadHandleKey< T > &origKey, const EventContext &ctx=Gaudi::Hive::currentContext()) const
	Create alias for the decorations, linked to the shallow copy. More...

Private Attributes
SG::ReadHandleKeyArray< T >	m_readKeys
	Keys for the decorations on the original object. More...

SG::WriteHandleKeyArray< T >	m_writeKeys
	Keys for decorations to alias for the shallow copy. More...

Detailed Description

template<class T>
class SG::ShallowCopyDecorDeps< T >

Helper to propagate decoration dependencies to a shallow copy.

When we do a shallow copy of ORIG to COPY, any decorations of ORIG are readable via COPY. However, the scheduler doesn't know about this. The scheduler keeps track of decoration dependencies via aliases of the form ORIG.DECOR. If one tries to use a ReadDecorHandle for COPY.DECOR, the scheduler won't be able to resolve that dependency because that alias doesn't exist — only ORIG.DECOR.

This class will help in propagating the decoration aliases from the original object to the shallow copy. The set of decorations does need to be specified in advance.

It is assumed that you have a Gaudi component which does the shallow copy, and that the original and copy are specified by a ReadHandleKey and a WriteHandleKey, respectively.

In the definition of the component class, add a ShallowCopyDecorDeps member as a property. The value of the property should be the list of decorations to be copied:

SG::ShallowCopyDecorDeps<MyObj> m_decorDeps
{ this, "DecorDeps", {"decor1", "decor2"},
  "List of decorations to propagate through the shallow copy." };

In the initialize() method, call initialize on the ShallowCopyDecorDeps object, passing in the read and write handle keys for the original object and the shallow copy:

ATH_CHECK( m_decorDeps.initialize (m_origKey, m_copyKey) );

Finally, after the copy has been recorded, call linkDecors, passing the read handle key for the original object:

ATH_CHECK( m_decorDeps.linkDecors (m_origKey, ctx) );

Definition at line 74 of file StoreGate/StoreGate/ShallowCopyDecorDeps.h.

Constructor & Destructor Documentation

◆ ShallowCopyDecorDeps()

template<class T >

template<class OWNER >

SG::ShallowCopyDecorDeps< T >::ShallowCopyDecorDeps	(	OWNER *	owner,
		const std::string &	name,
		std::initializer_list< std::string >	l,
		const std::string &	doc = `""`
	)

Auto-declaring Property constructor.

Parameters

owner	Owning component.
name	Name of the Property.
l	Default list of decorations to propagate.
doc	Documentation string.

Member Function Documentation

◆ initialize()

template<class T >

StatusCode SG::ShallowCopyDecorDeps< T >::initialize	(	const SG::ReadHandleKey< T > &	origKey,
		const SG::WriteHandleKey< T > &	copyKey,
		bool	used = `true`
	)

Initialize this property.

Call this from initialize().

Parameters

origKey	Key for the source of the shallow copy.
copyKey	Key for the result of the shallow copy.
used	If false, then this handle is not to be used. Instead of normal initialization, the keys will be cleared.

◆ linkDecors()

template<class T >

StatusCode SG::ShallowCopyDecorDeps< T >::linkDecors	(	const SG::ReadHandleKey< T > &	origKey,
		const EventContext &	ctx = `Gaudi::Hive::currentContext()`
	)		const