Class CPageBuffer

class CPageBuffer : public CActive;

Description

Derivation

• CBase - Base class for all classes to be instantiated on the heap.

• CActive - The core class of the active object abstraction.

• CPageBuffer - (No abstract)

Members

Defined in CPageBuffer:

• AddBytesL(const TDesC8 &)
• CloseWriteStream()
• CreateWriteStreamL()
• DoCancel()Implements cancellation of an outstanding request.
• NewL(CPrinterPort *)
• NewL(CPrinterPort *,TInt)
• RunL()Handles an active object's request completion event.
• StartFlush(TRequestStatus &)
• ~CPageBuffer()

Inherited from CActive:

• CActive(TInt)Constructs the active object with the specified priority.
• Cancel()Cancels the wait for completion of an outstanding request.
• Deque()Removes the active object from the active scheduler's list of active objects.
• EPriorityHighA priority higher than EPriorityUserInput.
• EPriorityIdleA low priority, useful for active objects representing background processing.
• EPriorityLowA priority higher than EPriorityIdle but lower than EPriorityStandard.
• EPriorityStandardMost active objects will have this priority.
• EPriorityUserInputA priority higher than EPriorityStandard; useful for active objects handling use...
• Extension_(TUint,TAny *&,TAny *)Extension function
• IsActive()constDetermines whether the active object has a request outstanding.
• IsAdded()constDetermines whether the active object has been added to the active scheduler's li...
• Priority()constGets the priority of the active object.
• RunError(TInt)Handles a leave occurring in the request completion event handler CActive::RunL(...
• SetActive()Indicates that the active object has issued a request and that it is now outstan...
• SetPriority(TInt)Sets the priority of the active object.
• TPriorityDefines standard priorities for active objects.
• iStatusThe request status associated with an asynchronous request.

Inherited from CBase:

• Delete(CBase *)Deletes the specified object.
• operator new(TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TAny *)Initialises the object to binary zeroes.
• operator new(TUint,TLeave)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TLeave,TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TUint)Allocates the object from the heap and then initialises its contents to binary z...

IMPORT_C static CPageBuffer* NewL(CPrinterPort *aPrinterPort);

Description

Parameters

CPrinterPort *aPrinterPort

Return value

CPageBuffer *

IMPORT_C static CPageBuffer* NewL(CPrinterPort *aPrinterPort, TInt aGranularity);

Description

Parameters

CPrinterPort *aPrinterPort TInt aGranularity

Return value

CPageBuffer *

IMPORT_C ~CPageBuffer();

Description

IMPORT_C void StartFlush(TRequestStatus &aRequestStatus);

Description

Parameters

TRequestStatus &aRequestStatus

IMPORT_C void AddBytesL(const TDesC8 &aDes);

Description

Parameters

const TDesC8 &aDes

IMPORT_C RWriteStream& CreateWriteStreamL();

Description

Return value

RWriteStream &

IMPORT_C void CloseWriteStream();

Description

virtual void DoCancel();

Description

Implements cancellation of an outstanding request.

This function is called as part of the active object's CActive::Cancel().

It must call the appropriate cancel function offered by the active object's asynchronous service provider. The asynchronous service provider's cancel is expected to act immediately.

CPageBuffer::DoCancel() must not wait for event completion; this is handled by CActive::Cancel().

See also:

• CActive::Cancel()Cancels the wait for completion of an outstanding request.

virtual void RunL();

Description

Handles an active object's request completion event.

A derived class must provide an implementation to handle the completed request. If appropriate, it may issue another request.

The function is called by the active scheduler when a request completion event occurs, i.e. after the active scheduler's WaitForAnyRequest() function completes.

Before calling this active object's CPageBuffer::RunL() function, the active scheduler has:

1. decided that this is the highest priority active object with a completed request

2. marked this active object's request as complete (i.e. the request is no longer outstanding)

CPageBuffer::RunL() runs under a trap harness in the active scheduler. If it leaves, then the active scheduler calls CActive::RunError(TInt) to handle the leave.

Note that once the active scheduler's Start() function has been called, all user code is run under one of the program's active object's CPageBuffer::RunL() or CActive::RunError(TInt) functions.

See also:

• CActiveScheduler::Start()Starts a new wait loop under the control of the current active scheduler.
• CActiveScheduler::Error(TInt)constHandles the result of a leave occurring in an active object’s RunL() function.
• CActiveScheduler::WaitForAnyRequest()Wait for an asynchronous request to complete.