GeneralDataStorage Class Reference

#include <deal.II/algorithms/general_data_storage.h>

Inheritance diagram for GeneralDataStorage:

Public Member Functions
	GeneralDataStorage ()=default
	GeneralDataStorage (const GeneralDataStorage &)=default
	GeneralDataStorage (GeneralDataStorage &&)=default
std::size_t	size () const
void	merge (const GeneralDataStorage &other_data)
template<class Stream >
void	print_info (Stream &stream)
void	reset ()
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
Data storage and access
template<typename Type >
void	add_unique_copy (const std::string &name, const Type &entry)
template<typename Type >
void	add_or_overwrite_copy (const std::string &name, const Type &entry)
template<typename Type >
void	add_unique_reference (const std::string &name, Type &entry)
template<typename Type >
void	add_or_overwrite_reference (const std::string &name, Type &entry)
template<typename Type , typename Arg , typename... Args>
Type &	get_or_add_object_with_name (const std::string &name, Arg &argument, Args &...arguments)
template<typename Type , typename Arg >
Type &	get_or_add_object_with_name (const std::string &name, Arg &argument)
template<typename Type , typename Arg , typename... Args>
Type &	get_or_add_object_with_name (const std::string &name, Arg &&argument, Args &&...arguments)
template<typename Type , typename Arg >
Type &	get_or_add_object_with_name (const std::string &name, Arg &&argument)
template<typename Type >
Type &	get_or_add_object_with_name (const std::string &name)
template<typename Type >
Type &	get_object_with_name (const std::string &name)
template<typename Type >
const Type &	get_object_with_name (const std::string &name) const
bool	stores_object_with_name (const std::string &name) const
void	remove_object_with_name (const std::string &name)
Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
unsigned int	n_subscriptions () const
template<typename StreamType >
void	list_subscribers (StreamType &stream) const
void	list_subscribers () const

Static Public Member Functions
static ::ExceptionBase &	ExcNameNotFound (std::string arg1)
static ::ExceptionBase &	ExcNameHasBeenFound (std::string arg1)
static ::ExceptionBase &	ExcTypeMismatch (std::string arg1, const char *arg2, const char *arg3)
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Private Types
using	map_value_type = decltype(counter_map)::value_type
using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
void	check_no_subscribers () const noexcept

Private Attributes
std::map< std::string, std::any >	any_data
std::atomic< unsigned int >	counter
std::map< std::string, unsigned int >	counter_map
std::vector< std::atomic< bool > * >	validity_pointers
const std::type_info *	object_info

Static Private Attributes
static std::mutex	mutex

Detailed Description

This class facilitates the storage of any general data. It offers a mechanism to store any amount of data, of any type, which is then made accessible by an identifier string.

When using this class, please cite [188].

Definition at line 41 of file general_data_storage.h.

Member Typedef Documentation

map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 229 of file subscriptor.h.

map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 234 of file subscriptor.h.

Constructor & Destructor Documentation

GeneralDataStorage() [1/3]

GeneralDataStorage::GeneralDataStorage ( )

default

Default constructor.

GeneralDataStorage() [2/3]

GeneralDataStorage::GeneralDataStorage ( const GeneralDataStorage & )

default

Copy constructor.

GeneralDataStorage() [3/3]

GeneralDataStorage::GeneralDataStorage ( GeneralDataStorage && )

default

Move constructor.

Member Function Documentation

size()

std::size_t GeneralDataStorage::size

(

)

const

Number of objects stored by this class instance.

Definition at line 23 of file general_data_storage.cc.

merge()

void GeneralDataStorage::merge

(

const GeneralDataStorage &

other_data

)

Merge the contents of other_data with this object.

Definition at line 30 of file general_data_storage.cc.

print_info()

template<class Stream >

void GeneralDataStorage::print_info

(

Stream &

stream

)

Print the contents of the internal cache to the stream.

Each key and value pair in the any_data map are printed on an individual line, with the std::string key listed first followed by the demangled type_id of the associated mapped type.

reset()

void GeneralDataStorage::reset

(

)

Clear all data stored in this class instance.

When you call this function, it destroys all objects you asked to be stored as copies, and it forgets about the references to data you asked to store by reference. As a consequence, you are now free to destroy the objects to which references were stored at whatever time you want – before or after the current GeneralDataStorage object is destroyed.

To clarify this point, consider the following small example:

GeneralDataStorage data;
 
{
  const double some_number = ...;
  data.add_unique_reference("value", some_number);
 
  // Adding either of these next two lines could fix the
  // issue, by removing the association of some_number with data:
  // data.remove_object_with_name("value");
  // data.reset();
} // some_number goes out of scope here
 
const double some_other_number
  = data.get_object_with_name<double>("value"); // Invalid call

In the code above, the data object has a longer scope than some_number. By the time we fetch the "value" from data , the reference to some_number is no longer valid.

Similarly, for data copied into a GeneralDataStorage object one should consider the scope under which it remains valid:

double* ptr_to_some_number = null_ptr;
 
{
  GeneralDataStorage data;
  const double some_number = ...;
  data.add_unique_copy("value", some_number);
 
  ptr_to_some_number = &(data.get_object_with_name<double>("value"));
} // The copy to some_number goes out of scope here
 
const double some_other_number
  = *ptr_to_some_number; // Invalid call

Similar to the first example, we must be conscious of the fact that the copies of any Type stored by data only remains valid while the GeneralDataStorage instance in which it is stored is alive.

Furthermore, as elucidated in the last example, the copy of the class instance (owned by GeneralDataStorage) that is being pointed to is no longer alive when the reset() function is called, or when it is removed via a call to remove_object_with_name().

GeneralDataStorage data;
double* ptr_to_some_number = null_ptr;
 
{
  const double some_number = ...;
  data.add_unique_copy("value", some_number);
 
  ptr_to_some_number = &(data.get_object_with_name<double>("value"));
 
  // The copy to some_number would go out of scope when either of
  // following two calls are made:
  data.remove_object_with_name("value");
  data.reset();
}
 
const double some_other_number
  = *ptr_to_some_number; // Invalid call

Definition at line 37 of file general_data_storage.cc.

add_unique_copy()

template<typename Type >

void GeneralDataStorage::add_unique_copy	(	const std::string &	name,
		const Type &	entry )

Store internally a copy of the given object. The copied object is owned by this class, and is accessible via reference through the get_object_with_name() method.

This function ensures that no entry with the given name is already stored by this class instance.

add_or_overwrite_copy()

template<typename Type >

void GeneralDataStorage::add_or_overwrite_copy	(	const std::string &	name,
		const Type &	entry )

Store internally a copy of the given object. The copied object is owned by this class, and is accessible via reference through the get_object_with_name() method.

This function does not perform any checks to ensure that the entry with the given name is already stored by this class instance. If the name does in fact point to existing data, then this is overwritten.

add_unique_reference()

template<typename Type >

void GeneralDataStorage::add_unique_reference	(	const std::string &	name,
		Type &	entry )

Add a reference to an already existing object. The object is not owned by this class, and the user has to guarantee that the referenced object lives longer than this class instance. The stored reference is accessible through the get_object_with_name() method.

This function ensures that no entry with the given name is already stored by this class instance.

add_or_overwrite_reference()

template<typename Type >

void GeneralDataStorage::add_or_overwrite_reference	(	const std::string &	name,
		Type &	entry )

Add a reference to an already existing object. The object is not owned by this class, and the user has to guarantee that the referenced object lives longer than this class instance. The stored reference is accessible through the get_object_with_name() method.

This function does not perform any checks to ensure that the entry with the given name is already stored by this class instance. If the name does in fact point to existing data, then this is overwritten.

get_or_add_object_with_name() [1/5]

template<typename Type , typename Arg , typename... Args>

Type & GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &	argument,
		Args &...	arguments )

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

A copy of an object of type Type , which is owned by this class instance, is generated by calling its constructor with the given set of arguments. For this function, the arguments are passed as lvalue references.

get_or_add_object_with_name() [2/5]

template<typename Type , typename Arg >

Type & GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &	argument )

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

Same as above for a single argument.

get_or_add_object_with_name() [3/5]

template<typename Type , typename Arg , typename... Args>

Type & GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &&	argument,
		Args &&...	arguments )

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

A copy of an object of type Type , which is owned by this class instance, is generated by calling its constructor with the given set of arguments. In contrast to the previous function of the same name, for this function the arguments are passed as rvalue references.

get_or_add_object_with_name() [4/5]

template<typename Type , typename Arg >

Type & GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &&	argument )

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

Same as above for a single argument.

get_or_add_object_with_name() [5/5]

template<typename Type >

Type & GeneralDataStorage::get_or_add_object_with_name

(

const std::string &

name

)

Same as above for default constructors.

get_object_with_name() [1/2]

template<typename Type >

Type & GeneralDataStorage::get_object_with_name

(

const std::string &

name

)

Return a reference to the object with given name.

This function throws an exception if either an object with the given name is not stored in this class, or if the object with the given name is neither of the exact specified Type nor a pointer to the Type.

get_object_with_name() [2/2]

template<typename Type >

const Type & GeneralDataStorage::get_object_with_name

(

const std::string &

name

)

const

Return a constant reference to the object with the given name.

This function throws an exception if either an object with the given name is not stored in this class, or if the object with the given name is neither of the exact specified Type nor a pointer to the Type.

stores_object_with_name()

bool GeneralDataStorage::stores_object_with_name

(

const std::string &

name

)

const

Find out if we store an object with given name.

Definition at line 44 of file general_data_storage.cc.

remove_object_with_name()

void GeneralDataStorage::remove_object_with_name

(

const std::string &

name

)

Remove the object with given name.

Definition at line 51 of file general_data_storage.cc.

subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 135 of file subscriptor.cc.

unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Unsubscribes a user from the object.

Note

The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 155 of file subscriptor.cc.

n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

list_subscribers() [1/2]

template<typename StreamType >

void Subscriptor::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 203 of file subscriptor.cc.

serialize()

template<class Archive >

void Subscriptor::serialize ( Archive & ar, const unsigned int version )

inlineinherited

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

check_no_subscribers()

void Subscriptor::check_no_subscribers ( ) const

privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note

Since this function is just a consistency check it does nothing in release mode.

If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 52 of file subscriptor.cc.

Member Data Documentation

any_data

std::map<std::string, std::any> GeneralDataStorage::any_data

private

Arbitrary user data, identified by a string.

Definition at line 347 of file general_data_storage.h.

counter

std::atomic<unsigned int> Subscriptor::counter

mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 218 of file subscriptor.h.

counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map

mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 224 of file subscriptor.h.

validity_pointers

std::vector<std::atomic<bool> *> Subscriptor::validity_pointers

mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 240 of file subscriptor.h.

object_info

const std::type_info* Subscriptor::object_info

mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 248 of file subscriptor.h.

mutex

std::mutex Subscriptor::mutex

staticprivateinherited

A mutex used to ensure data consistency when accessing the mutable members of this class. This lock is used in the subscribe() and unsubscribe() functions, as well as in list_subscribers().

Definition at line 271 of file subscriptor.h.

---

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

• include/deal.II/algorithms/general_data_storage.h
• source/algorithms/general_data_storage.cc