Public Member Functions | Public Attributes | Private Types | Private Attributes | Friends

ACE_Weak_Bound_Ptr< X, ACE_LOCK > Class Template Reference

This class implements support for a weak pointer that complements ACE_Strong_Bound_Ptr. More...

#include <Bound_Ptr.h>

Collaboration diagram for ACE_Weak_Bound_Ptr< X, ACE_LOCK >:
Collaboration graph
[legend]

List of all members.

Public Member Functions

 ACE_Weak_Bound_Ptr (X *p=0)
 ACE_Weak_Bound_Ptr (const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &r)
 Copy constructor binds this and r to the same object.
 ACE_Weak_Bound_Ptr (const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &r)
 Constructor binds this and r to the same object.
 ~ACE_Weak_Bound_Ptr (void)
 Destructor.
void operator= (const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &r)
 Assignment operator that binds this and r to the same object.
void operator= (const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &r)
 Assignment operator that binds this and r to the same object.
bool operator== (const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &r) const
bool operator== (const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &r) const
bool operator== (X *p) const
bool operator!= (const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &r) const
 Inequality operator, which is the opposite of equality.
bool operator!= (const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &r) const
 Inequality operator, which is the opposite of equality.
bool operator!= (X *p) const
 Inequality operator, which is the opposite of equality.
ACE_Strong_Bound_Ptr< X, ACE_LOCK > operator-> (void) const
 Redirection operator.
ACE_Strong_Bound_Ptr< X, ACE_LOCK > strong (void) const
X * unsafe_get (void) const
void reset (X *p=0)
long add_ref (void)
 Increment the reference count on the underlying object.
long remove_ref (void)
bool null (void) const
 Allows us to check for NULL on all ACE_Weak_Bound_Ptr objects.

Public Attributes

 ACE_ALLOC_HOOK_DECLARE
 Declare the dynamic allocation hooks.

Private Types

typedef X X_t
typedef ACE_Bound_Ptr_Counter
< ACE_LOCK > 		COUNTER
 The ACE_Bound_Ptr_Counter type.

Private Attributes

COUNTER * counter_
 The reference counter.
X * ptr_
 The underlying object.

Friends

class ACE_Strong_Bound_Ptr< X, ACE_LOCK >

Detailed Description

template<class X, class ACE_LOCK>
class ACE_Weak_Bound_Ptr< X, ACE_LOCK >

This class implements support for a weak pointer that complements ACE_Strong_Bound_Ptr.

Unlike ACE_Strong_Bound_Ptr, assigning or copying instances of an ACE_Weak_Bound_Ptr will not automatically increment the reference count of the underlying object. What ACE_Weak_Bound_Ptr does is preserve the knowledge that the object is in fact reference counted, and thus provides an alternative to raw pointers where non-ownership associations must be maintained. When the last instance of an ACE_Strong_Bound_Ptr that references a particular object is destroyed or overwritten, the corresponding ACE_Weak_Bound_Ptr instances are set to NULL.

Definition at line 266 of file Bound_Ptr.h.

Member Typedef Documentation

template<class X, class ACE_LOCK>
typedef ACE_Bound_Ptr_Counter<ACE_LOCK> ACE_Weak_Bound_Ptr< X, ACE_LOCK >::COUNTER [private]

The ACE_Bound_Ptr_Counter type.

Definition at line 373 of file Bound_Ptr.h.

template<class X, class ACE_LOCK>
typedef X ACE_Weak_Bound_Ptr< X, ACE_LOCK >::X_t [private]

Definition at line 368 of file Bound_Ptr.h.

Constructor & Destructor Documentation

template<class X , class ACE_LOCK >
ACE_Weak_Bound_Ptr< X, ACE_LOCK >::ACE_Weak_Bound_Ptr ( X *  p = 0  )  [inline, explicit]

Constructor that initializes an ACE_Weak_Bound_Ptr to point to the object <p> immediately.

Definition at line 320 of file Bound_Ptr.inl.

  : counter_ (COUNTER::create_weak ()),
    ptr_ (p)
{
}

template<class X , class ACE_LOCK >
ACE_Weak_Bound_Ptr< X, ACE_LOCK >::ACE_Weak_Bound_Ptr ( const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &  r  )  [inline]

Copy constructor binds this and r to the same object.

Definition at line 327 of file Bound_Ptr.inl.

  : counter_ (r.counter_),
    ptr_ (r.ptr_)
{
  COUNTER::attach_weak (this->counter_);
}

template<class X , class ACE_LOCK >
ACE_Weak_Bound_Ptr< X, ACE_LOCK >::ACE_Weak_Bound_Ptr ( const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &  r  )  [inline]

Constructor binds this and r to the same object.

Definition at line 335 of file Bound_Ptr.inl.

  : counter_ (r.counter_),
    ptr_ (r.ptr_)
{
  COUNTER::attach_weak (this->counter_);
}

template<class X , class ACE_LOCK >
ACE_Weak_Bound_Ptr< X, ACE_LOCK >::~ACE_Weak_Bound_Ptr ( void   )  [inline]

Destructor.

Definition at line 343 of file Bound_Ptr.inl.

{
  COUNTER::detach_weak (this->counter_);
}

Member Function Documentation

template<class X , class ACE_LOCK >
long ACE_Weak_Bound_Ptr< X, ACE_LOCK >::add_ref ( void   )  [inline]

Increment the reference count on the underlying object.

Returns the new reference count on the object. This function may be used to integrate the bound pointers into an external reference counting mechanism such as those used by COM or CORBA servants.

Definition at line 477 of file Bound_Ptr.inl.

{
  return COUNTER::attach_strong (counter_);
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::null ( void   )  const [inline]

Allows us to check for NULL on all ACE_Weak_Bound_Ptr objects.

Definition at line 457 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return true;

  return this->ptr_ == 0;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator!= ( X *  p  )  const [inline]

Inequality operator, which is the opposite of equality.

Definition at line 426 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return p != 0;

  return this->ptr_ != p;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator!= ( const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &  r  )  const [inline]

Inequality operator, which is the opposite of equality.

Definition at line 415 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return r.ptr_ != 0;

  return this->ptr_ != r.ptr_;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator!= ( const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &  r  )  const [inline]

Inequality operator, which is the opposite of equality.

Definition at line 404 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return r.ptr_ != 0;

  return this->ptr_ != r.ptr_;
}

template<class X , class ACE_LOCK >
ACE_Strong_Bound_Ptr< X, ACE_LOCK > ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator-> ( void   )  const [inline]

Redirection operator.

It returns a temporary strong pointer and makes use of the chaining properties of operator-> to ensure that the underlying object does not disappear while you are using it. If you are certain of the lifetimes of the object, and do not want to incur the locking overhead, then use the unsafe_get method instead.

Definition at line 437 of file Bound_Ptr.inl.

{
  return ACE_Strong_Bound_Ptr<X, ACE_LOCK> (*this);
}

template<class X , class ACE_LOCK >
void ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator= ( const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &  r  )  [inline]

Assignment operator that binds this and r to the same object.

Definition at line 360 of file Bound_Ptr.inl.

{
  // This will work if &rhs == this, by first increasing the ref count
  COUNTER *new_counter = rhs.counter_;
  COUNTER::attach_weak (new_counter);
  COUNTER::detach_weak (this->counter_);
  this->counter_ = new_counter;
  this->ptr_ = rhs.ptr_;
}

template<class X , class ACE_LOCK >
void ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator= ( const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &  r  )  [inline]

Assignment operator that binds this and r to the same object.

Definition at line 349 of file Bound_Ptr.inl.

{
  // This will work if &rhs == this, by first increasing the ref count
  COUNTER *new_counter = rhs.counter_;
  COUNTER::attach_weak (new_counter);
  COUNTER::detach_weak (this->counter_);
  this->counter_ = new_counter;
  this->ptr_ = rhs.ptr_;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator== ( const ACE_Strong_Bound_Ptr< X, ACE_LOCK > &  r  )  const [inline]

Equality operator that returns true if the ACE_Weak_Bound_Ptr and ACE_Strong_Bound_Ptr objects point to the same underlying object.

Note:
It also returns true if both objects have just been instantiated and not used yet.

Definition at line 382 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return r.ptr_ == 0;

  return this->ptr_ == r.ptr_;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator== ( X *  p  )  const [inline]

Equality operator that returns true if the ACE_Weak_Bound_Ptr and the raw pointer point to the same underlying object.

Definition at line 393 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return p == 0;

  return this->ptr_ == p;
}

template<class X , class ACE_LOCK >
bool ACE_Weak_Bound_Ptr< X, ACE_LOCK >::operator== ( const ACE_Weak_Bound_Ptr< X, ACE_LOCK > &  r  )  const [inline]

Equality operator that returns true if both ACE_Weak_Bound_Ptr objects point to the same underlying object.

Note:
It also returns true if both objects have just been instantiated and not used yet.

Definition at line 371 of file Bound_Ptr.inl.

{
  // A weak pointer must behave as though it is automatically set to null
  // if the underlying object has been deleted.
  if (COUNTER::object_was_deleted (this->counter_))
    return r.ptr_ == 0;

  return this->ptr_ == r.ptr_;
}

template<class X , class ACE_LOCK >
long ACE_Weak_Bound_Ptr< X, ACE_LOCK >::remove_ref ( void   )  [inline]

Decrement the reference count on the underlying object, which is deleted if the count has reached zero. Returns the new reference count on the object. This function may be used to integrate the bound pointers into an external reference counting mechanism such as those used by COM or CORBA servants.

Definition at line 483 of file Bound_Ptr.inl.

{
  long new_obj_ref_count = COUNTER::detach_strong (counter_);
  if (new_obj_ref_count == 0)
    {
      delete this->ptr_;
      this->ptr_ = 0;
    }
  return new_obj_ref_count;
}

template<class X , class ACE_LOCK >
void ACE_Weak_Bound_Ptr< X, ACE_LOCK >::reset ( X *  p = 0  )  [inline]

Resets the ACE_Weak_Bound_Ptr to refer to a different underlying object.

Definition at line 468 of file Bound_Ptr.inl.

{
  COUNTER *old_counter = this->counter_;
  this->counter_ = COUNTER::create_weak ();
  this->ptr_ = p;
  COUNTER::detach_weak (old_counter);
}

template<class X , class ACE_LOCK >
ACE_Strong_Bound_Ptr< X, ACE_LOCK > ACE_Weak_Bound_Ptr< X, ACE_LOCK >::strong ( void   )  const [inline]

Obtain a strong pointer corresponding to this weak pointer. This function is useful to create a temporary strong pointer for conversion to a reference.

Definition at line 443 of file Bound_Ptr.inl.

{
  return ACE_Strong_Bound_Ptr<X, ACE_LOCK> (*this);
}

template<class X , class ACE_LOCK >
X * ACE_Weak_Bound_Ptr< X, ACE_LOCK >::unsafe_get ( void   )  const [inline]

Get the pointer value. Warning: this does not affect the reference count of the underlying object, so it may disappear on you while you are using it if you are not careful.

Definition at line 449 of file Bound_Ptr.inl.

{
  // We do not check if the object has been deleted, since this operation
  // is defined to be unsafe!
  return this->ptr_;
}

Friends And Related Function Documentation

template<class X, class ACE_LOCK>
friend class ACE_Strong_Bound_Ptr< X, ACE_LOCK > [friend]

Definition at line 370 of file Bound_Ptr.h.

Member Data Documentation

template<class X, class ACE_LOCK>
ACE_Weak_Bound_Ptr< X, ACE_LOCK >::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Definition at line 365 of file Bound_Ptr.h.

template<class X, class ACE_LOCK>
COUNTER* ACE_Weak_Bound_Ptr< X, ACE_LOCK >::counter_ [private]

The reference counter.

Definition at line 376 of file Bound_Ptr.h.

template<class X, class ACE_LOCK>
X* ACE_Weak_Bound_Ptr< X, ACE_LOCK >::ptr_ [private]

The underlying object.

Definition at line 379 of file Bound_Ptr.h.

The documentation for this class was generated from the following files:
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines
Generated on Thu Dec 9 2010 11:57:58 for ACE by  doxygen 1.7.0