Class MPagePool

class MPagePool;

Description

Interface to a page pool, the storage abstraction used by the B-trees API.

The interface is abstract and handles pages as TAny pointers. It is left to derived classes to implement page storage in a particular storage medium, such as memory or disk.

Members

Defined in MPagePool:
AcquireL(), AllocL(), AssignL(), Delete(), DeleteL(), DoDeleteL(), LockL(), Pop(), PushL(), Unlock(), UpdateL()

IMPORT_C void PushL();

Description

Pushes this object onto the cleanup stack.

inline void Pop();

Description

Do a pop from the cleanup stack.

virtual TPageAbandonFunction AcquireL()=0;

Description

Returns a function that abandons all locked pages for this page pool.

Return value

TPageAbandonFunction A function that abandons all locked pages for this page pool.

virtual TAny *AllocL()=0;

Description

Return value

TAny *

virtual TAny *LockL(TPageRef aRef)=0;

Description

Locks a page and returns a pointer to it.

Parameters

TPageRef aRef Reference to the page to lock

Return value

TAny * Locked page

virtual TPageRef AssignL(const TAny *aPage, TPageReclamation aReclamation=EPageDeleteOnly)=0;

Description

Parameters

const TAny *aPage TPageReclamation aReclamation

Return value

TPageRef

virtual void UpdateL(const TAny *aPage)=0;

Description

Updates a page.

This can be used for cached pages that may have become outdated.

Parameters

const TAny *aPage Page to update

virtual void Unlock(const TAny *aPage, TPageChange aChange=EPageNoChange)=0;

Description

Unlocks a page.

Parameters

const TAny *aPage Page to unlock TPageChange aChange How the page should be treated once it is unlocked

IMPORT_C void Delete(TPageRef aRef);

Description

Deletes a page, ignoring any errors.

Parameters

TPageRef aRef Reference to the page to delete

IMPORT_C void DeleteL(TPageRef aRef);

Description

Deletes a page, leaving if an error occurs.

Parameters

TPageRef aRef Reference to the page to delete

protected: virtual void DoDeleteL(TPageRef aRef)=0;

Description

Parameters

TPageRef aRef