InPlaceAnyHolder< siz, AccessPolicy > Class Template Reference

#include "lib/opaque-holder.hpp"

Description

template<size_t siz, class AccessPolicy = InPlaceAnyHolder_unrelatedTypes>
class lib::InPlaceAnyHolder< siz, AccessPolicy >

Inline buffer to hold and own an object while concealing the concrete type.

The object is given either as ctor parameter or by direct assignment; it is copy-constructed into the buffer. It is necessary to specify the required buffer storage space as a template parameter. InPlaceAnyHolder may be created empty or cleared afterwards, and this #empty() state may be detected at runtime. In a similar vein, when the stored object has a bool validity check, this can be accessed though isValid(). Moreover !empty() && isValid() may be tested as by bool conversion of the Holder object. The whole compound is copyable if and only if the contained object is copyable.

Note

assertion failure when trying to place an instance not fitting into given size.

not threadsafe!

Todo:

add support for moving of rvalue refs

Definition at line 210 of file opaque-holder.hpp.

Public Member Functions
template<class SUB >
	InPlaceAnyHolder (SUB const &obj)
	InPlaceAnyHolder (InPlaceAnyHolder const &ref)
void	clear ()
bool	empty () const
template<class SUB >
SUB &	get () const
	re-accessing the concrete contained object. More...
bool	isValid () const
	operator bool () const
InPlaceAnyHolder &	operator= (InPlaceAnyHolder const &ref)
template<class SUB >
InPlaceAnyHolder &	operator= (SUB const &newContent)

Classes
struct	Buff
	concrete subclass to manage a specific kind of contained object. More...
struct	Buffer
	Inner capsule managing the contained object (interface) More...
struct	EmptyBuff
	special case: no stored object More...

Protected Member Functions
BaseP	asBase () const
	< More...
Buffer &	buff ()
const Buffer &	buff () const
void	clone_inBuff (InPlaceAnyHolder const &ref)
void	killBuffer ()
void	make_emptyBuff ()
template<class SUB >
void	place_inBuff (SUB const &obj)

Private Types
enum	{ BUFFSIZE = sizeof(Buffer) }
typedef AccessPolicy::Base *	BaseP

Private Attributes
char	storage_ [BUFFSIZE]
	embedded buffer actually holding the concrete Buff object, which in turn holds and manages the target object. More...

Member Function Documentation

asBase()

BaseP asBase ( ) const

inlineprotected

<

backdoor e.g. for comparisons

Definition at line 368 of file opaque-holder.hpp.

get()

SUB& get ( ) const

inline

re-accessing the concrete contained object.

This requires exact knowledge of the actual type of the element currently in storage. OpaqueHolder does not provide any "probing" or visitation mechanism.

Remarks

You might consider lib::Variant or some visitor instead.

Exceptions

lumiera::error::Logic	when conversion/access fails
lumiera::error::Invalid	when accessing an empty holder

Definition at line 461 of file opaque-holder.hpp.

Referenced by WrappedStandardExeBuilder::__call__().

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Member Data Documentation

storage_

char storage_[BUFFSIZE]

private

embedded buffer actually holding the concrete Buff object, which in turn holds and manages the target object.

Note

Invariant: always contains a valid Buffer subclass

Definition at line 321 of file opaque-holder.hpp.

Inheritance diagram for InPlaceAnyHolder< siz, AccessPolicy >:

Collaboration diagram for InPlaceAnyHolder< siz, AccessPolicy >:

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

• opaque-holder.hpp