libMesh::ReferenceCountedObject< T > Class Template Reference

This class implements reference counting. More...

#include <reference_counted_object.h>

Inheritance diagram for libMesh::ReferenceCountedObject< T >:

Public Member Functions
	~ReferenceCountedObject ()
	Destructor.

Static Public Member Functions
static std::string	get_info ()
	Gets a string containing the reference information.
static void	print_info (std::ostream &out_stream=libMesh::out)
	Prints the reference information, by default to libMesh::out.
static unsigned int	n_objects ()
	Prints the number of outstanding (created, but not yet destroyed) objects.
static void	enable_print_counter_info ()
	Methods to enable/disable the reference counter output from print_info().
static void	disable_print_counter_info ()

Protected Types
typedef std::map< std::string, std::pair< unsigned int, unsigned int > >	Counts
	Data structure to log the information.

Protected Member Functions
	ReferenceCountedObject ()
	Constructor.
	ReferenceCountedObject (const ReferenceCountedObject &other)
	Also, increment the counter if the copy-constructor is called.
	ReferenceCountedObject (ReferenceCountedObject &&other) noexcept
	Move constructor, must be declared noexcept.
ReferenceCountedObject &	operator= (const ReferenceCountedObject &)
	Copy assignment operator does nothing - we're copying an already-allocated object over an already-allocated object, so the counts for this class shouldn't change.
void	increment_constructor_count (const std::string &name) noexcept
	Increments the construction counter.
void	increment_destructor_count (const std::string &name) noexcept
	Increments the destruction counter.

Static Protected Attributes
static Counts	_counts
	Actually holds the data.
static Threads::atomic< unsigned int >	_n_objects
	The number of objects.
static Threads::spin_mutex	_mutex
	Mutual exclusion object to enable thread-safe reference counting.
static bool	_enable_print_counter = true
	Flag to control whether reference count information is printed when print_info is called.

Detailed Description

template<typename T>
class libMesh::ReferenceCountedObject< T >

This class implements reference counting.

Any class that is properly derived from this class will get reference counted, provided that the library is configured with --enable-reference-counting and you are compiling with DEBUG defined. For example, the following is sufficient to define the class Foo as a reference counted class:

class Foo : public ReferenceCountedObject<Foo>
{
 public:
 
   Foo  () {}
 
   ~Foo () {}
 
   void bar ();
 
 private:
};

If the library is configured with --disable-reference-counting or DEBUG is not defined then this class does nothing. All members are inlined and empty, so they should effectively disappear.

Author

Benjamin S. Kirk

Date

2002-2007

Definition at line 65 of file reference_counted_object.h.

Member Typedef Documentation

Counts

typedef std::map<std::string, std::pair<unsigned int, unsigned int> > libMesh::ReferenceCounter::Counts

protectedinherited

Data structure to log the information.

The log is identified by the class name.

Definition at line 119 of file reference_counter.h.

Constructor & Destructor Documentation

ReferenceCountedObject() [1/3]

template<typename T >

libMesh::ReferenceCountedObject< T >::ReferenceCountedObject ( )

inlineprotected

Constructor.

Protected so that you cannot instantiate a ReferenceCountedObject, only derive from it.

Definition at line 74 of file reference_counted_object.h.

  {
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
    increment_constructor_count(typeid(T).name());
 
#endif
  }

References libMesh::ReferenceCounter::increment_constructor_count().

ReferenceCountedObject() [2/3]

template<typename T >

libMesh::ReferenceCountedObject< T >::ReferenceCountedObject ( const ReferenceCountedObject< T > &  other )

inlineprotected

Also, increment the counter if the copy-constructor is called.

Definition at line 86 of file reference_counted_object.h.

    : ReferenceCounter(other)
  {
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
    increment_constructor_count(typeid(T).name());
 
#endif
  }

References libMesh::ReferenceCounter::increment_constructor_count().

ReferenceCountedObject() [3/3]

template<typename T >

libMesh::ReferenceCountedObject< T >::ReferenceCountedObject ( ReferenceCountedObject< T > &&  other )

inlineprotectednoexcept

Move constructor, must be declared noexcept.

Definition at line 99 of file reference_counted_object.h.

    : ReferenceCounter(std::move(other))
  {
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
    increment_constructor_count(typeid(T).name());
 
#endif
  }

References libMesh::ReferenceCounter::increment_constructor_count().

~ReferenceCountedObject()

template<typename T >

libMesh::ReferenceCountedObject< T >::~ReferenceCountedObject ( )

inline

Destructor.

Definition at line 127 of file reference_counted_object.h.

  {
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
    increment_destructor_count(typeid(T).name());
 
#endif
  }

References libMesh::ReferenceCounter::increment_destructor_count().

Member Function Documentation

disable_print_counter_info()

void libMesh::ReferenceCounter::disable_print_counter_info ( )

staticinherited

Definition at line 100 of file reference_counter.C.

{
  _enable_print_counter = false;
  return;
}

References libMesh::ReferenceCounter::_enable_print_counter.

enable_print_counter_info()

void libMesh::ReferenceCounter::enable_print_counter_info ( )

staticinherited

Methods to enable/disable the reference counter output from print_info().

Enabled by default.

Definition at line 94 of file reference_counter.C.

{
  _enable_print_counter = true;
  return;
}

References libMesh::ReferenceCounter::_enable_print_counter.

Referenced by libMesh::LibMeshInit::~LibMeshInit().

get_info()

std::string libMesh::ReferenceCounter::get_info ( )

staticinherited

Gets a string containing the reference information.

Definition at line 47 of file reference_counter.C.

{
#if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
  std::ostringstream oss;
 
  oss << '\n'
      << " ---------------------------------------------------------------------------- \n"
      << "| Reference count information                                                |\n"
      << " ---------------------------------------------------------------------------- \n";
 
  for (const auto & [name, cd] : _counts)
    oss << "| " << name << " reference count information:\n"
        << "|  Creations:    " << cd.first    << '\n'
        << "|  Destructions: " << cd.second << '\n';
 
  oss << " ---------------------------------------------------------------------------- \n";
 
  return oss.str();
 
#else
 
  return "";
 
#endif
}

References libMesh::ReferenceCounter::_counts.

Referenced by libMesh::ReferenceCounter::print_info().

increment_constructor_count()

void libMesh::ReferenceCounter::increment_constructor_count ( const std::string &  name )

inlineprotectednoexceptinherited

Increments the construction counter.

Should be called in the constructor of any derived class that will be reference counted.

Definition at line 183 of file reference_counter.h.

{
  libmesh_try
  {
    Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
    std::pair<unsigned int, unsigned int> & p = _counts[name];
    p.first++;
  }
  libmesh_catch (...)
  {
    auto stream = libMesh::err.get();
    stream->exceptions(stream->goodbit); // stream must not throw
    libMesh::err << "Encountered unrecoverable error while calling "
                 << "ReferenceCounter::increment_constructor_count() "
                 << "for a(n) " << name << " object." << std::endl;
    std::terminate();
  }
}

References libMesh::err, libMesh::BasicOStreamProxy< charT, traits >::get(), and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< T >::ReferenceCountedObject(), libMesh::ReferenceCountedObject< T >::ReferenceCountedObject(), and libMesh::ReferenceCountedObject< T >::ReferenceCountedObject().

increment_destructor_count()

void libMesh::ReferenceCounter::increment_destructor_count ( const std::string &  name )

inlineprotectednoexceptinherited

Increments the destruction counter.

Should be called in the destructor of any derived class that will be reference counted.

Definition at line 207 of file reference_counter.h.

{
  libmesh_try
  {
    Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
    std::pair<unsigned int, unsigned int> & p = _counts[name];
    p.second++;
  }
  libmesh_catch (...)
  {
    auto stream = libMesh::err.get();
    stream->exceptions(stream->goodbit); // stream must not throw
    libMesh::err << "Encountered unrecoverable error while calling "
                 << "ReferenceCounter::increment_destructor_count() "
                 << "for a(n) " << name << " object." << std::endl;
    std::terminate();
  }
}

References libMesh::err, libMesh::BasicOStreamProxy< charT, traits >::get(), and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< T >::~ReferenceCountedObject().

n_objects()

static unsigned int libMesh::ReferenceCounter::n_objects ( )

inlinestaticinherited

Prints the number of outstanding (created, but not yet destroyed) objects.

Definition at line 85 of file reference_counter.h.

  { return _n_objects; }

References libMesh::ReferenceCounter::_n_objects.

Referenced by libMesh::LibMeshInit::~LibMeshInit().

operator=()

template<typename T >

ReferenceCountedObject & libMesh::ReferenceCountedObject< T >::operator= ( const ReferenceCountedObject< T > &  )

inlineprotected

Copy assignment operator does nothing - we're copying an already-allocated object over an already-allocated object, so the counts for this class shouldn't change.

There are also no non-static members in this or the base class to copy, so there is nothing for us to actually do.

Definition at line 116 of file reference_counted_object.h.

  {
    return *this;
  }

print_info()

void libMesh::ReferenceCounter::print_info ( std::ostream &  out_stream = libMesh::out )

staticinherited

Prints the reference information, by default to libMesh::out.

Definition at line 81 of file reference_counter.C.

{
  if (_enable_print_counter)
    out_stream << ReferenceCounter::get_info();
}

References libMesh::ReferenceCounter::_enable_print_counter, and libMesh::ReferenceCounter::get_info().

Referenced by libMesh::LibMeshInit::~LibMeshInit().

Member Data Documentation

_counts

ReferenceCounter::Counts libMesh::ReferenceCounter::_counts

staticprotectedinherited

Actually holds the data.

Definition at line 124 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::get_info().

_enable_print_counter

bool libMesh::ReferenceCounter::_enable_print_counter = true

staticprotectedinherited

Flag to control whether reference count information is printed when print_info is called.

Definition at line 143 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::disable_print_counter_info(), libMesh::ReferenceCounter::enable_print_counter_info(), and libMesh::ReferenceCounter::print_info().

_mutex

Threads::spin_mutex libMesh::ReferenceCounter::_mutex

staticprotectedinherited

Mutual exclusion object to enable thread-safe reference counting.

Definition at line 137 of file reference_counter.h.

_n_objects

Threads::atomic< unsigned int > libMesh::ReferenceCounter::_n_objects

staticprotectedinherited

The number of objects.

Print the reference count information when the number returns to 0.

Definition at line 132 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::n_objects(), libMesh::ReferenceCounter::ReferenceCounter(), libMesh::ReferenceCounter::ReferenceCounter(), libMesh::ReferenceCounter::ReferenceCounter(), and libMesh::ReferenceCounter::~ReferenceCounter().

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

• include/base/reference_counted_object.h