PTLib  Version 2.10.4
PSafePtrBase Class Reference

This class defines a base class for thread-safe pointer to an object. More...

#include <safecoll.h>

Inheritance diagram for PSafePtrBase:
PObject PSafePtrMultiThreaded

List of all members.

Public Member Functions

virtual void Assign (const PSafePtrBase &ptr)
virtual void Assign (const PSafeCollection &safeCollection)
virtual void Assign (PSafeObject *obj)
virtual void Assign (PINDEX idx)
Overrides from class PObject
virtual Comparison Compare (const PObject &obj) const
 Compare the pointers.
Operations
virtual void SetNULL ()
 Set the pointer to NULL, unlocking/dereferencing existing pointer value.
bool operator! () const
 Return true if pointer is NULL.
PSafetyMode GetSafetyMode () const
 Get the locking mode used by this pointer.
virtual PBoolean SetSafetyMode (PSafetyMode mode)
 Change the locking mode used by this pointer.
const PSafeCollectionGetCollection () const
 Get the associated collection this pointer may be contained in.

Protected Types

enum  EnterSafetyModeOption { WithReference, AlreadyReferenced }
enum  ExitSafetyModeOption { WithDereference, NoDereference }

Protected Member Functions

virtual void Next ()
virtual void Previous ()
virtual void DeleteObject (PSafeObject *obj)
PBoolean EnterSafetyMode (EnterSafetyModeOption ref)
void ExitSafetyMode (ExitSafetyModeOption ref)

Protected Attributes

const PSafeCollectioncollection
PSafeObjectcurrentObject
PSafetyMode lockMode

Construction

 PSafePtrBase (PSafeObject *obj=NULL, PSafetyMode mode=PSafeReference)
 Create a new pointer to a PSafeObject.
 PSafePtrBase (const PSafeCollection &safeCollection, PSafetyMode mode, PINDEX idx)
 Create a new pointer to a PSafeObject.
 PSafePtrBase (const PSafeCollection &safeCollection, PSafetyMode mode, PSafeObject *obj)
 Create a new pointer to a PSafeObject.
 PSafePtrBase (const PSafePtrBase &enumerator)
 Copy the pointer to the PSafeObject.
 ~PSafePtrBase ()
 Unlock and dereference the PSafeObject this is pointing to.

Detailed Description

This class defines a base class for thread-safe pointer to an object.

This is part of a set of classes to solve the general problem of a collection (eg a PList or PDictionary) of objects that needs to be a made thread safe. Any thread can add, read, write or remove an object with both the object and the database of objects itself kept thread safe.

NOTE: the PSafePtr will allow safe and mutexed access to objects but is not thread safe itself! You should not share PSafePtr instances across threads.

See the PSafeObject class for more details.


Member Enumeration Documentation

Enumerator:
WithReference 
AlreadyReferenced 
Enumerator:
WithDereference 
NoDereference 

Constructor & Destructor Documentation

PSafePtrBase::PSafePtrBase ( PSafeObject obj = NULL,
PSafetyMode  mode = PSafeReference 
) [protected]

Create a new pointer to a PSafeObject.

An optional locking mode may be provided to lock the object for reading or writing and automatically unlock it on destruction.

Note that this version is not associated with a collection so the ++ and -- operators will not work.

Parameters:
objPhysical object to point to.
modeLocking mode for the object
PSafePtrBase::PSafePtrBase ( const PSafeCollection safeCollection,
PSafetyMode  mode,
PINDEX  idx 
) [protected]

Create a new pointer to a PSafeObject.

An optional locking mode may be provided to lock the object for reading or writing and automatically unlock it on destruction.

The idx'th entry of the collection is pointed to by this object. If the idx is beyond the size of the collection, the pointer is NULL.

Parameters:
safeCollectionCollection pointer will enumerate
modeLocking mode for the object
idxIndex into collection to point to
PSafePtrBase::PSafePtrBase ( const PSafeCollection safeCollection,
PSafetyMode  mode,
PSafeObject obj 
) [protected]

Create a new pointer to a PSafeObject.

An optional locking mode may be provided to lock the object for reading or writing and automatically unlock it on destruction.

The obj parameter is only set if it contained in the collection, otherwise the pointer is NULL.

Parameters:
safeCollectionCollection pointer will enumerate
modeLocking mode for the object
objInital object in collection to point to
PSafePtrBase::PSafePtrBase ( const PSafePtrBase enumerator) [protected]

Copy the pointer to the PSafeObject.

This will create a copy of the pointer with the same locking mode and lock on the PSafeObject. It will also increment the reference count on the PSafeObject as well.

Parameters:
enumeratorPointer to copy

Unlock and dereference the PSafeObject this is pointing to.


Member Function Documentation

virtual void PSafePtrBase::Assign ( const PSafePtrBase ptr) [virtual]

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::Assign ( const PSafeCollection safeCollection) [virtual]

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::Assign ( PSafeObject obj) [virtual]

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::Assign ( PINDEX  idx) [virtual]

Reimplemented in PSafePtrMultiThreaded.

virtual Comparison PSafePtrBase::Compare ( const PObject obj) const [virtual]

Compare the pointers.

Note this is not a value comparison and will only return EqualTo if the two PSafePtrBase instances are pointing to the same instance.

Parameters:
objOther instance to compare against

Reimplemented from PObject.

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::DeleteObject ( PSafeObject obj) [protected, virtual]

Reimplemented in PSafePtrMultiThreaded.

const PSafeCollection* PSafePtrBase::GetCollection ( ) const [inline]

Get the associated collection this pointer may be contained in.

References collection.

Get the locking mode used by this pointer.

References lockMode.

virtual void PSafePtrBase::Next ( ) [protected, virtual]

Reimplemented in PSafePtrMultiThreaded.

bool PSafePtrBase::operator! ( ) const [inline]

Return true if pointer is NULL.

References currentObject.

virtual void PSafePtrBase::Previous ( ) [protected, virtual]

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::SetNULL ( ) [virtual]

Set the pointer to NULL, unlocking/dereferencing existing pointer value.

Reimplemented in PSafePtrMultiThreaded.

virtual PBoolean PSafePtrBase::SetSafetyMode ( PSafetyMode  mode) [virtual]

Change the locking mode used by this pointer.

If the function returns false, then the object has been flagged for deletion and the calling thread should immediately cease use of the object. This instance pointer will be set to NULL.

Parameters:
modeNew locking mode

Reimplemented in PSafePtrMultiThreaded.


Member Data Documentation

Referenced by GetCollection().


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