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CHeaderCodec Class Reference

class CHeaderCodec : public CBase

An abstract HTTP header codec.

Each instance of a concrete subclass of CHeaderCodec is associated with, and owned by, a specific CProtocolHandler . It provides on-demand encoding/decoding of HTTP header data, between the generic format used by clients/filters to formulate requests and interpret responses, and the raw format used by the transport handlers (and origin servers/gateways/etc.)

The CHeaderCodec has an associated instance of a sub-class of each of CHeaderReader and CHeaderWriter . It delegates the actual encoding and decoding function to these instances.

Header codecs provide a mechanism for extensibility whereby if one codec can't decode (or encode) a given header, it locates a codec that can, and then delegates the task to that codec instead.

Inherits from

Public Member Functions
~CHeaderCodec ()
TBool CanDecode ( RStringF )
TBool CanEncode ( RStringF )
IMPORT_C void DecodeHeaderL ( RHeaderField &)
IMPORT_C void EncodeHeaderL ( RHeaderField &)
CHeaderCodec * FindDelegateCodecL ( RStringF )
Protected Member Functions
CHeaderCodec ()
IMPORT_C void ConstructL ()
Private Member Functions
void Reserved1 ()
void Reserved2 ()
Inherited Functions
CBase::CBase()
CBase::Delete(CBase *)
CBase::Extension_(TUint,TAny *&,TAny *)
CBase::operator new(TUint)
CBase::operator new(TUint,TAny *)
CBase::operator new(TUint,TLeave)
CBase::operator new(TUint,TLeave,TUint)
CBase::operator new(TUint,TUint)
CBase::~CBase()
Protected Attributes
CHeaderReader * iReader
CHeaderWriter * iWriter
Private Attributes
CHeaderCodec * iDelegateCodec

Constructor & Destructor Documentation

CHeaderCodec()

IMPORT_C CHeaderCodec ( ) [protected]

Default constructor.

~CHeaderCodec()

IMPORT_C ~CHeaderCodec ( ) [virtual]

Intended Usage: Destructor - cleans up and releases resources to the system.

Member Functions Documentation

CanDecode(RStringF)

TBool CanDecode ( RStringF aHeaderField ) const [pure virtual]

Intended Usage: Concrete header codec classes must implement this method to indicate to the framework whether their concrete CHeaderReader is capable of decoding the named header field.

Parameters

RStringF aHeaderField (in) A proxy for the header field to be encoded

CanEncode(RStringF)

TBool CanEncode ( RStringF aHeaderField ) const [pure virtual]

Intended Usage: Concrete header codec classes must implement this method to indicate to the framework whether their concrete CHeaderWriter is capable of encoding the named header field.

Parameters

RStringF aHeaderField (in) A proxy for the header field to be encoded

ConstructL()

IMPORT_C void ConstructL ( ) [protected]

Second phase construction in which any necessary allocation is done Implementations of this interface may leave with standard erros like KErrNoMemory if there is insufficient memory for allocation in the second phase.

DecodeHeaderL(RHeaderField &)

IMPORT_C void DecodeHeaderL ( RHeaderField & aHeader ) const

Decode the supplied header field. This method uses the associated concrete CHeaderReader object to do a conversion of the field into the generic internal representation from the raw form.

leave
KErrNotSupported if a codec that supports decoding this header cannot be found

Parameters

RHeaderField & aHeader (in) A proxy for the header field to be decoded

EncodeHeaderL(RHeaderField &)

IMPORT_C void EncodeHeaderL ( RHeaderField & aHeader ) const

Encode the supplied header field. This method uses the associated concrete CHeaderWriter object to do a conversion of the field into raw form from the generic internal representation.

leave
KErrNotSupported if a codec that supports encoding this header cannot be found

Parameters

RHeaderField & aHeader (in) A proxy for the header field to be encoded

FindDelegateCodecL(RStringF)

CHeaderCodec * FindDelegateCodecL ( RStringF aHeaderField ) const [pure virtual]

Intended Usage: Concrete header codecs must be implement this method if they wish to delegate the encoding/decoding of particular header fields to a different codec. This would be done if the codec doesn't have the ability itself to do the encode/decode but can locate an alternative that does. This function may leave with a Standard Symbian OS error code. eg. KErrNoMemory

The caller takes ownership of the returned codec.
leave
KErrNoMemory, Not enough memory to create object.

Parameters

RStringF aHeaderField (in) A proxy for the header field to be encoded

Reserved1()

void Reserved1 ( ) [private, inline, virtual]

Intended Usage: Reserve a slot in the v-table to preserve future BC

Reserved2()

void Reserved2 ( ) [private, inline, virtual]

Intended Usage: Reserve a slot in the v-table to preserve future BC

Member Data Documentation

CHeaderCodec * iDelegateCodec

CHeaderCodec * iDelegateCodec [private]

The most recently-obtained delegate codec

CHeaderReader * iReader

CHeaderReader * iReader [protected]

The owned header reader object that does actual decoding of header fields.

CHeaderWriter * iWriter

CHeaderWriter * iWriter [protected]

The owned header writer object that does actual encoding of header fields.

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All rights reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License v1.0.