ReSIProcate之header宏

 

Header宏defineHeader主要分布三处，分别是

SipMessage.cxx defineHeader(_header, _name, _type, _rfc)

Headers.hxx defineHeader(_enum, _name, _type, _rfc)

Headers.cxx defineHeader(_enum, _name, _type, _reference)

SipMessage宏展开为调用的函数，而Headers宏展开则定义了一个类。

 

以RetryAfter为例

宏 defineHeader(RetryAfter,"Retry-After", UInt32Category, "RFC 3261");

 

调用方式

SipMessage* tryLater;

tryLater->header(h_RetryAfter);

 

 

相关宏展开之后

SipMessage.cxx 调用函数

const H_RetryAfter::Type& SipMessage::header(const H_RetryAfter& headerType) const { HeaderFieldValueList* hfvs = ensureHeaders(headerType.getTypeNum(), true); if (hfvs->getParserContainer() == 0) { hfvs->setParserContainer(new ParserContainer<H_RetryAfter::Type>(hfvs, headerType.getTypeNum())); } return dynamic_cast<ParserContainer<H_RetryAfter::Type>*>(hfvs->getParserContainer())->front(); } H_RetryAfter::Type& SipMessage::header(const H_RetryAfter& headerType) { HeaderFieldValueList* hfvs = ensureHeaders(headerType.getTypeNum(), true); if (hfvs->getParserContainer() == 0) { hfvs->setParserContainer(new ParserContainer<H_RetryAfter::Type>(hfvs, headerType.getTypeNum())); } return dynamic_cast<ParserContainer<H_RetryAfter::Type>*>(hfvs->getParserContainer())->front(); }

 

Heads.hxx 类声明

class H_RetryAfter :public HeaderBase                            

{                                                              

   public:                                                    

      RESIP_HeapCount(H_RetryAfter);                              

      enum {Single = true};                                    

      typedef UInt32Category Type;                                     

      UnusedChecking(RetryAfter);                                   

      static Type&knownReturn(ParserContainerBase* container);

      virtual ParserContainerBase*makeContainer(HeaderFieldValueList* hfvs) const;      

      virtual Headers::Type getTypeNum()const;                

      virtual void merge(SipMessage&, constSipMessage&);      

      H_RetryAfter();                                             

};                                                             

extern H_RetryAfterh_RetryAfter

 

 

Headers.cxx 类定义                                                                 

Headers::Type H_RetryAfter::getTypeNum() const {return Headers::RetryAfter;} void H_RetryAfter::merge(SipMessage& target, const SipMessage& embedded) { if (embedded.exists(*this)) { target.header(*this) = embedded.header(*this); } } H_RetryAfter::H_RetryAfter() { Headers::CommaTokenizing[Headers::_enum+1] = bool(Type::commaHandling & ParserCategory::CommasAllowedOutputMulti); Headers::CommaEncoding[Headers::_enum+1] = bool(Type::commaHandling & 2); Headers::HeaderNames[Headers::_enum+1] = _name; Headers::Multi[Headers::_enum+1] = false; HeaderBase::theHeaderInstances[Headers::_enum+1] = this; } UInt32Category& H_RetryAfter::knownReturn(ParserContainerBase* container) { return dynamic_cast<ParserContainer< UInt32Category>*>(container)->front(); } ParserContainerBase* H_RetryAfter::makeContainer(HeaderFieldValueList* hfvs) const { return new ParserContainer<UInt32Category>(hfvs,Headers::_enum); } H_RetryAfter resip::H_RetryAfter

 

 

从上面可以看出，使用宏目的是方便添加新的SIP组成零件，避免重复代码量。