PTLib  Version 2.10.10
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 PSafePtr< PMonitoredSockets > PSafePtrMultiThreaded

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. More...
 
virtual void PrintOn (ostream &strm) const
 Output the contents of the object to the stream. More...
 
Operations
virtual void SetNULL ()
 Set the pointer to NULL, unlocking/dereferencing existing pointer value. More...
 
bool operator! () const
 Return true if pointer is NULL. More...
 
PSafetyMode GetSafetyMode () const
 Get the locking mode used by this pointer. More...
 
virtual PBoolean SetSafetyMode (PSafetyMode mode)
 Change the locking mode used by this pointer. More...
 
const PSafeCollectionGetCollection () const
 Get the associated collection this pointer may be contained in. More...
 
- Public Member Functions inherited from PObject
virtual ~PObject ()
 
virtual PObjectClone () const
 Create a copy of the class on the heap. More...
 
virtual PINDEX HashFunction () const
 This function yields a hash value required by the PDictionary class. More...
 
virtual const char * GetClass (unsigned ancestor=0) const
 Get the current dynamic type of the object instance. More...
 
PBoolean IsClass (const char *cls) const
 
virtual PBoolean InternalIsDescendant (const char *clsName) const
 Determine if the dynamic type of the current instance is a descendent of the specified class. More...
 
virtual Comparison CompareObjectMemoryDirect (const PObject &obj) const
 Determine the byte wise comparison of two objects. More...
 
bool operator== (const PObject &obj) const
 Compare the two objects. More...
 
bool operator!= (const PObject &obj) const
 Compare the two objects. More...
 
bool operator< (const PObject &obj) const
 Compare the two objects. More...
 
bool operator> (const PObject &obj) const
 Compare the two objects. More...
 
bool operator<= (const PObject &obj) const
 Compare the two objects. More...
 
bool operator>= (const PObject &obj) const
 Compare the two objects. More...
 
virtual void ReadFrom (istream &strm)
 Input the contents of the object from the stream. More...
 

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)
 
virtual void LockPtr ()
 
virtual void UnlockPtr ()
 
- Protected Member Functions inherited from PObject
 PObject ()
 Constructor for PObject, made protected so cannot ever create one on its own. More...
 

Protected Attributes

const PSafeCollectioncollection
 
PSafeObjectcurrentObject
 
PSafetyMode lockMode
 

Construction

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

Additional Inherited Members

- Public Types inherited from PObject
enum  Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
 Result of the comparison operation performed by the Compare() function. More...
 
- Static Public Member Functions inherited from PObject
static const char * Class ()
 Get the name of the class as a C string. More...
 
static Comparison InternalCompareObjectMemoryDirect (const PObject *obj1, const PObject *obj2, PINDEX size)
 Internal function caled from CompareObjectMemoryDirect() More...
 

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
PSafePtrBase::~PSafePtrBase ( )

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)
protectedvirtual

Reimplemented in PSafePtrMultiThreaded.

PBoolean PSafePtrBase::EnterSafetyMode ( EnterSafetyModeOption  ref)
protected
void PSafePtrBase::ExitSafetyMode ( ExitSafetyModeOption  ref)
protected
const PSafeCollection* PSafePtrBase::GetCollection ( ) const
inline

Get the associated collection this pointer may be contained in.

References collection.

PSafetyMode PSafePtrBase::GetSafetyMode ( ) const
inline

Get the locking mode used by this pointer.

References lockMode.

virtual void PSafePtrBase::LockPtr ( )
inlineprotectedvirtual

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::Next ( )
protectedvirtual

Reimplemented in PSafePtrMultiThreaded.

bool PSafePtrBase::operator! ( ) const
inline

Return true if pointer is NULL.

References currentObject.

virtual void PSafePtrBase::Previous ( )
protectedvirtual

Reimplemented in PSafePtrMultiThreaded.

virtual void PSafePtrBase::PrintOn ( ostream &  strm) const
virtual

Output the contents of the object to the stream.

The exact output is dependent on the exact semantics of the descendent class. This is primarily used by the standard operator<< function.

The default behaviour is to print the class name.

Reimplemented from PObject.

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.

virtual void PSafePtrBase::UnlockPtr ( )
inlineprotectedvirtual

Reimplemented in PSafePtrMultiThreaded.

Member Data Documentation

const PSafeCollection* PSafePtrBase::collection
protected

Referenced by GetCollection().

PSafeObject* PSafePtrBase::currentObject
protected

Referenced by operator!().

PSafetyMode PSafePtrBase::lockMode
protected

Referenced by GetSafetyMode().


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