Class TCachePagePool

class TCachePagePool : public MPagePool;

Description

Provides a page pool with cached pages.

It is an intermediary class, used in the definition of page pools that use a cache, such as RFilePagePool and RStorePagePool.

Derivation

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

• TCachePagePool - Provides a page pool with cached pages

Members

Defined in TCachePagePool:
AcquireL(), AllocL(), AssignL(), DoDeleteL(), ExtendL(), Flush(), FlushL(), LockL(), Purge(), ReadL(), Set(), TCachePagePool(), TCachePagePool(), Unlock(), UpdateL(), WriteL()

Inherited from MPagePool:
Delete(), DeleteL(), Pop(), PushL()

See also:

• RFilePagePool
• RStorePagePool

protected: inline TCachePagePool();

Description

protected: inline TCachePagePool(CPageCache &aCache);

Description

Parameters

CPageCache &aCache

inline void Set(CPageCache &aCache);

Description

Sets the page cache for the pool.

Parameters

CPageCache &aCache The page cache for the pool.

virtual IMPORT_C TPageAbandonFunction AcquireL();

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 IMPORT_C TAny *AllocL();

Description

Allocates an unassigned page.

Return value

TAny * Newly allocated page.

virtual IMPORT_C TAny *LockL(TPageRef aRef);

Description

Locks a page and returns a pointer to it.

Parameters

TPageRef aRef Reference to page to lock

Return value

TAny * Locked page

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

Description

Assigns a reference to a new page and unlocks it.

Parameters

const TAny *aPage Page to assign TPageReclamation aReclamation Flag for page reclaimation settings

Return value

TPageRef Reference to page

virtual IMPORT_C void UpdateL(const TAny *aPage);

Description

Updates a page.

Parameters

const TAny *aPage Page to update

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

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 TInt Flush();

Description

Flush all pages in this pool from the cache.

It ensures that any dirty pages are written into persistent storage, but does not remove them from the cache.

Return value

TInt KErrNone if successful, otherwise another of the system-wide error codes.

IMPORT_C void FlushL();

Description

Flushes all pages in this pool from the cache, leaving with a system-wide error code if an error occurs.

IMPORT_C void Purge();

Description

Purge all pages in this pool from the cache.

This discards all pages from the cache, without saving dirty pages.

protected: virtual IMPORT_C void DoDeleteL(TPageRef aRef);

Description

Parameters

TPageRef aRef

private: virtual TPageRef ExtendL(const TAny *aPage, TPageReclamation aReclamation)=0;

Description

Parameters

const TAny *aPage TPageReclamation aReclamation

Return value

TPageRef

private: virtual void WriteL(TPageRef aRef, const TAny *aPage, TPageChange aChange)=0;

Description

Parameters

TPageRef aRef const TAny *aPage TPageChange aChange

private: virtual void ReadL(TPageRef aRef, TAny *aPage)=0;

Description

Parameters

TPageRef aRef TAny *aPage