CObject Class Reference

class CObject : public CBase

Implements reference counting to track concurrent references to itself.

An object of this type arranges automatic destruction of itself when the final reference is removed.

A reference counting object is any object which has CObject as its base class. Constructing a CObject derived type or calling its Open() member function adds a reference to that object by adding one to the reference count; calling its Close() member function removes a reference by subtracting one from the reference count; when the last user of the object calls Close(), the reference count becomes zero and the object is automatically destroyed.

Inherits from

Constructor & Destructor Documentation

CObject()

IMPORT_CCObject()

Constructs the object and initializes the reference count to one.

Once constructed, a reference counting object cannot be deleted until its reference count is reduced to zero.

CObject::Close

~CObject()

IMPORT_C~CObject()

Destructor.

It removes this reference counting object from its object container, a CObjectCon type.

panic
E32USER-CBase 33 if the reference count is not zero when the destructor is called.
CObjectCon

Member Functions Documentation

AccessCount()

TInt AccessCount()const [inline]

Gets the number of open references to this reference counting object.

Close()

IMPORT_C voidClose()[virtual]

Closes this reference counting object.

The default behaviour decrements the reference count by one. If this becomes zero, then the function deletes this reference counting object.

Where a derived class implements its own version of this function, it can use the protected member function Dec() to decrement the reference count or make a base call to this function.

panic
E32USER-CBase 34 if the reference count is negative when this function is called.

Dec()

voidDec()[protected, inline]

Subtracts one from the reference count.

This function is called by the default implementation of the Close() member function of this class.

CObject::Close

Extension_(TUint, TAny *&, TAny *)

IMPORT_C TIntExtension_(TUintaExtensionId,
TAny *&a0,
TAny *a1
)[protected, virtual]

Extension function

Parameters

TUint aExtensionId
TAny *& a0
TAny * a1

FullName()

IMPORT_C TFullNameFullName()const [virtual]

Gets the full name of this reference counting object.

By default, the full name is a concatenation of this reference counting object's name with the full name of its owning reference counting object.

Inc()

voidInc()[protected, inline]

Adds one to the reference count.

This function is called by the default implementation of the Open() member function of this class.

CObject::Open

Name()

IMPORT_C TNameName()const [virtual]

Gets the name of this reference counting object.

The default behaviour provided by this function depends on whether a name has been explicitly set into the object:

if a name has previously been set, then the function returns that name.

if a name has not been set, then the function builds a default name. This is fourteen characters and has the format: LOCAL-nnnnnnnn where nnnnnnnn is the hexadecimal character representation of this reference counting object's address. This default name is, therefore, guaranteed to be unique within the current process.

Open()

IMPORT_C TIntOpen()[virtual]

Opens this reference counting object.

The default behaviour increments the reference count by one and returns KErrNone. Where a derived class implements its own version of this function, it must either use the protected member function Inc() to increment the reference count or make a base call to this function.

Owner()

CObject *Owner()const [inline]

Gets a pointer to the reference counting object which owns this reference counting object.

SetName(const TDesC *)

IMPORT_C TIntSetName(const TDesC *aName)

Sets or clears this reference counting object's name.

To set the name, the specified descriptor must contain the name to be set. Once the name has been successfully set, then the specified source descriptor can be discarded.

To clear an existing name, specify a NULL argument.

panic
USER 11 if the length of aName is greater than KMaxName for a 16-bit descriptor.
panic
USER 23 if the length of aName is greater than KMaxName for an 8-bit descriptor.

Parameters

const TDesC * aNameA pointer to the descriptor containing the name to be set, or NULL if an existing name is to be cleared.

SetNameL(const TDesC *)

IMPORT_C voidSetNameL(const TDesC *aName)

Sets or clears this reference counting object's name, and leaves on error.

To set the name, the specified descriptor must contain the name to be set. Once the name has been successfully set, then the specified source descriptor can be discarded.

To clear an existing name, specify a NULL argument.

The function leaves if there is insufficient memory.

panic
USER 11 if the length of aName is greater than KMaxName for a 16-bit descriptor.
panic
USER 23 if the length of aName is greater than KMaxName for an 8-bit descriptor.

Parameters

const TDesC * aNameA pointer to the descriptor containing the name to be set, or NULL if an existing name is to be cleared.

SetOwner(CObject *)

voidSetOwner(CObject *anOwner)[inline]

Sets the owner of this reference counting object.

If this reference counting object already has an owner, then all knowledge of that owner is lost.

Parameters

CObject * anOwnerA pointer to the reference counting object which is to be the new owner of this reference counting object.

UniqueID()

TInt UniqueID()const [protected, inline]

Gets this reference counting object's unique ID.

The unique ID is an integer which is a property of the object container. It forms part of the identity of all reference counting objects and is the same value for all reference counting objects held within the same object container.

CObjectCon

Member Data Documentation

__DECLARE_TEST

__DECLARE_TEST[private]

TInt iAccessCount

TInt iAccessCount[private]

CObjectCon * iContainer

CObjectCon *iContainer[private]

HBufC * iName

HBufC *iName[private]

CObject * iOwner

CObject *iOwner[private]

TAny * iSpare1

TAny *iSpare1[private]

TAny * iSpare2

TAny *iSpare2[private]