TAO下IDL结构定义编译文件分析2005-09-21 lwx 每个IDL的定义的结构经过TAOIDL编译器编译将生成一些结构编码的函数的定义。主要分为TypeCode的处理函数和Any的处理函及其CDR编码的处理。每个IDL的定义的结构经过TAOIDL编译器编译将生成一些结构编码的函数的定义。主要分为TypeCode的处理函数和Any的处理函及其CDR编码的处理。由结构到Any的流化和解析，析构，及其结构与TypedCode处理组成。结构到Any类型是通过TAO的内部模板TAO::Any_Dual_Impl_T来实现。结构流编码通过TAO_OutputCDR,TAO_inputCDR. IDL定义如下 // 告警信息定义 struct AlarmInfo { GeneralizedTime eventTime; ObjectInstance source; ObjectClass sourceClass; NotificationIdentifier notificationId; CorrelatedNotifications alarmInfoCorrelatedNotifications; ProbableCause alarmInfoProbableCause; SpecificProblems alarmInfoSpecificProblems; PerceivedSeverity alarmInfoPerceivedSeverity; boolean backedUpStatus; ObjectInstance backUpObject; TrendIndication alarmInfoTrendIndication; ThresholdInfo alarmInfoThresholdInfo; AttributeChangeList stateChangeDefinition; AttributeList monitoredAttributes; ProposedRepairActions alarmInfoProposedRepairActions; AdditionalString additionalText; AdditionalInformation additionalInfo; }; 编译生成的文件*C.h/cpp struct AlarmInfo { typedef AlarmInfo_var _var_type; static void _tao_any_destructor (void *); TAO_String_Manager eventTime; nms::ObjectInstance source; nms::ObjectClass sourceClass; nms::NotificationIdentifier notificationId; nms::CorrelatedNotifications alarmInfoCorrelatedNotifications; nms::ProbableCause alarmInfoProbableCause; nms::SpecificProblems alarmInfoSpecificProblems; nms::PerceivedSeverity alarmInfoPerceivedSeverity; CORBA::Boolean backedUpStatus; nms::ObjectInstance backUpObject; nms::TrendIndication alarmInfoTrendIndication; nms::ThresholdInfo alarmInfoThresholdInfo; nms::AttributeChangeList stateChangeDefinition; nms::AttributeList monitoredAttributes; nms::ProposedRepairActions alarmInfoProposedRepairActions; TAO_String_Manager additionalText; nms::AdditionalInformation additionalInfo; }; Ø 1 里面包含一个静态成员函数是析构AlarmInfo指针内存空间 void nms::AlarmInfo::_tao_any_destructor ( void *_tao_void_pointer ) { AlarmInfo *_tao_tmp_pointer = ACE_static_cast (AlarmInfo *, _tao_void_pointer); delete _tao_tmp_pointer; } 在CPP还定义的Typdecode的函数，并设置函数指针 static CORBA::TypeCode _tc_TAO_tc_nms_AlarmInfo ( CORBA::tk_struct, sizeof (_oc_nms_AlarmInfo), (char *) &_oc_nms_AlarmInfo, 0, sizeof (nms::AlarmInfo) ); namespace nms { ::CORBA::TypeCode_ptr _tc_AlarmInfo = &_tc_TAO_tc_nms_AlarmInfo; } Ø 2 定义AlarmInfo 到的Any析构的函数 void nms::AlarmInfo::_tao_any_destructor ( void *_tao_void_pointer ) { AlarmInfo *_tao_tmp_pointer = ACE_static_cast (AlarmInfo *, _tao_void_pointer); delete _tao_tmp_pointer; } Ø 3 结构对象AlarmInfo放入Any的打包 void operator<<= ( CORBA::Any &_tao_any, const nms::AlarmInfo &_tao_elem ) { TAO::Any_Dual_Impl_T<nms::AlarmInfo>::insert_copy ( _tao_any, nms::AlarmInfo::_tao_any_destructor, nms::_tc_AlarmInfo, _tao_elem ); } Ø 4 结构对象AlarmInfo从Any的解析出来 // Extraction to non-const pointer (deprecated). CORBA::Boolean operator>>= ( const CORBA::Any &_tao_any, nms::AlarmInfo *&_tao_elem ) { return _tao_any >>= ACE_const_cast ( const nms::AlarmInfo *&, _tao_elem ); } Ø 结构与TAO内部的实现类的关系 TAO::Any_Dual_Impl_T<nms::AlarmInfo>::insert_copy (…) 具体的结构到Any的模板实现类，放入insert，吸取extract，结构对象指针value，编码，解码。 template<typename T> class Any_Basic_Impl_T : public Any_Impl { public: Any_Basic_Impl_T (CORBA::TypeCode_ptr, const T & val); virtual ~Any_Basic_Impl_T (void); static void insert (CORBA::Any &, CORBA::TypeCode_ptr, const T &); static CORBA::Boolean extract (const CORBA::Any &, CORBA::TypeCode_ptr, T &); virtual CORBA::Boolean marshal_value (TAO_OutputCDR &); CORBA::Boolean demarshal_value (TAO_InputCDR &); virtual void _tao_decode (TAO_InputCDR & ACE_ENV_ARG_DECL_WITH_DEFAULTS); virtual const void *value (void) const; static Any_Basic_Impl_T<T> *create_empty (CORBA::TypeCode_ptr); private: T value_; }; Ø 在编译的IDL的文件中产生了一个*C.i的文件，该文件主要是将定义的数据结构类型流化到CDR的对象中，及其从CDR流中解析出来。 Ø 结构到ANY的操作符 void operator<<= (CORBA::Any &, const nms::AlarmInfo &); // copying version void operator<<= (CORBA::Any &, nms::AlarmInfo*); // noncopying version CORBA::Boolean operator>>= (const CORBA::Any &, nms::AlarmInfo *&); // deprecated CORBA::Boolean operator>>= (const CORBA::Any &, const nms::AlarmInfo *&); Ø 结构到CDR的流化和解码处理 CORBA::Boolean operator<< (TAO_OutputCDR &, const nms::AlarmInfo &); CORBA::Boolean operator>> (TAO_InputCDR &, nms::AlarmInfo &); 流化成CDR格式的流 ACE_INLINE CORBA::Boolean operator<< ( TAO_OutputCDR &strm, const nms::AlarmInfo &_tao_aggregate ) { return (strm << _tao_aggregate.eventTime.in ()) && (strm << _tao_aggregate.source) && (strm << _tao_aggregate.sourceClass) && (strm << _tao_aggregate.notificationId) && (strm << _tao_aggregate.alarmInfoCorrelatedNotifications) && (strm << _tao_aggregate.alarmInfoProbableCause) && (strm << _tao_aggregate.alarmInfoSpecificProblems) && (strm << _tao_aggregate.alarmInfoPerceivedSeverity) && (strm << CORBA::Any::from_boolean (_tao_aggregate.backedUpStatus)) && (strm << _tao_aggregate.backUpObject) && (strm << _tao_aggregate.alarmInfoTrendIndication) && (strm << _tao_aggregate.alarmInfoThresholdInfo) && (strm << _tao_aggregate.stateChangeDefinition) && (strm << _tao_aggregate.monitoredAttributes) && (strm << _tao_aggregate.alarmInfoProposedRepairActions) && (strm << _tao_aggregate.additionalText.in ()) && (strm << _tao_aggregate.additionalInfo); } 可以见到IDL的数据结构与流化是比较独立分开的。CORBA的CDR编码是通过IDL中规范定义的基本数据类型来判断类型的流化。经过编译的IDL定义的生成的C++结构是比较干净，基本不带其他信息，或者成员，所以在编写CORBA的程序的时候，我们不要再定义相同的C++数据结构，我们可以直接使用IDL编译后的C++结构。
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