//============================================================================= // File: field.h // Contents: Declarations for DwField // Maintainer: Doug Sauder // WWW: http://www.fwb.gulf.net/~dwsauder/mimepp.html // // Copyright (c) 1996, 1997 Douglas W. Sauder // All rights reserved. // // IN NO EVENT SHALL DOUGLAS W. SAUDER BE LIABLE TO ANY PARTY FOR DIRECT, // INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF // THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF DOUGLAS W. SAUDER // HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // // DOUGLAS W. SAUDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT // NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A // PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" // BASIS, AND DOUGLAS W. SAUDER HAS NO OBLIGATION TO PROVIDE MAINTENANCE, // SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. // //============================================================================= #ifndef DW_FIELD_H #define DW_FIELD_H #include #ifndef DW_CONFIG_H #include #endif #ifndef DW_STRING_H #include #endif #ifndef DW_MSGCMP_H #include #endif class DwHeaders; class DwFieldBody; //============================================================================= //+ Name DwField -- Class representing a MIME header field //+ Description //. {\tt DwField} represents a header field as described in RFC-822. //. According to RFC-822, a field contains a field name and a field body. //. In MIME++, a {\tt DwField} contains three elements: a {\tt DwString} //. that contains its field name, a {\tt DwString} that contains its //. field body, and a {\tt DwFieldBody} object that contains a broken-down //. (that is, parsed) version of its field body. //. //. In the tree (broken-down) representation of message, a {\tt DwField} //. object is always an intermediate node, having a parent node and a single //. child node. The parent node is the {\tt DwHeaders} object that contains //. it. The child node is the {\tt DwFieldBody} object it contains. //. //. To get and set the field name, use the member functions //. {\tt FieldNameStr()} and {\tt SetFieldNameStr()}. //. To get and set the field body, use the member functions //. {\tt FieldBodyStr()} and {\tt SetFieldBodyStr()}. //. To get and set the {\tt DwFieldBody} object, use {\tt FieldBody()} //. and {\tt SetFieldBody()}. //. //. A {\tt DwField} object can be included in a list of {\tt DwField} //. objects; usually this is the list of {\tt DwField} objects maintained //. by its parent {\tt DwHeaders} object. To get the next {\tt DwField} //. object in a list, use the member function {\tt Next()}. //============================================================================= // Last updated 1997-08-23 //+ Noentry ~DwField _CreateFieldBody mFieldNameStr mFieldBodyStr //+ Noentry mFieldBody _PrintDebugInfo class DW_EXPORT DwField : public DwMessageComponent { friend class DwHeaders; public: DwField(); DwField(const DwField& aField); DwField(const DwString& aStr, DwMessageComponent* aParent=0); //. The first constructor is the default constructor, which sets the //. {\tt DwField} object's field name and field body to the empty //. string, set its parent to {\tt NULL}, and sets its {\tt DwFieldBody} //. object to {\tt NULL}. //. //. The second constructor is the copy constructor, which performs //. a deep copy of {\tt aField}. //. The parent of the new {\tt DwField} object is set to {\tt NULL}. //. //. The third constructor copies {\tt aStr} to the {\tt DwField} //. object's string representation and sets {\tt aParent} as its parent. //. The virtual member function {\tt Parse()} should be called immediately //. after this constructor in order to parse the string representation. //. Unless it is {\tt NULL}, {\tt aParent} should point to an object of //. a class derived from {\tt DwHeaders}. virtual ~DwField(); const DwField& operator = (const DwField& aField); //. This is the assignment operator, which performs a deep copy of //. {\tt aField}. The parent node of the {\tt DwField} object //. is not changed. virtual void Parse(); //. This virtual function, inherited from {\tt DwMessageComponent}, //. executes the parse method for {\tt DwField} objects. The parse //. method creates or updates the broken-down representation from the //. string representation. For {\tt DwField} objects, the parse method //. parses the string representation, sets the values of the field //. name string and the field body string, and creates an instance //. of the appropriate subclass of {\tt DwFieldBody}. This member //. function also calls the {\tt Parse()} member function of its //. contained {\tt DwFieldBody} object. //. //. You should call this member function after you set or modify the //. string representation, and before you access the field name, the //. field body, or the contained {\tt DwFieldBody} object. //. //. This function clears the is-modified flag. virtual void Assemble(); //. This virtual function, inherited from {\tt DwMessageComponent}, //. executes the assemble method for {\tt DwField} objects. The //. assemble method creates or updates the string representation from //. the broken-down representation. In more concrete terms, the //. assemble method builds the string representation from the field //. name and the string representation of the contained {\tt DwFieldBody} //. object. This member function calls the {\tt Assemble()} member //. function of its contained {\tt DwFieldBody} object. //. //. You should call this member function after you modify either the //. field name or the contained {\tt DwFieldBody} object, and before //. you retrieve the string representation. //. //. This function clears the is-modified flag. virtual DwMessageComponent* Clone() const; //. This virtual function, inherited from {\tt DwMessageComponent}, //. creates a new {\tt DwField} on the free store that has the same //. value as this {\tt DwField} object. The basic idea is that of //. a virtual copy constructor. DwFieldBody* FieldBody() const; //. Returns the {\tt DwFieldBody} object contained by this {\tt DwField} //. object. If there is no field body, {\tt NULL} will be returned. const DwString& FieldNameStr() const; //. Returns the field name of this header field as a string. const DwString& FieldBodyStr() const; //. Returns the field body of this header field as a string. DwField* Next() const; //. Returns the next {\tt DwField} object following this //. {\tt DwField} object in the list contained in a {\tt DwHeaders}. //. Returns {\tt NULL} if this object is last in the list. void SetFieldBody(DwFieldBody* aFieldBody); //. Sets the {\tt DwFieldBody} object contained by this object. void SetFieldNameStr(const DwString& aStr); //. Sets the field name of this header field. void SetFieldBodyStr(const DwString& aStr); //. Sets the field body of this header field. void SetNext(const DwField* aField); //. This {\it advanced} function sets {\tt aField} as the next field //. following this field in the list of fields contained in the headers. //. Since {\tt DwHeaders} contains member functions for adding //. {\tt DwField} objects to its list, this function should be //. avoided for most applications. static DwField* NewField(const DwString& aStr, DwMessageComponent* aParent); //. Creates a new {\tt DwField} object on the free store. //. If the static data member {\tt sNewField} is {\tt NULL}, //. this member function will create a new {\tt DwField} //. and return it. Otherwise, {\tt NewField()} will call //. the user-supplied function pointed to by {\tt sNewField}, //. which is assumed to return an object from a class derived from //. {\tt DwField}, and return that object. static DwFieldBody* CreateFieldBody(const DwString& aFieldName, const DwString& aFieldBody, DwMessageComponent* aParent); //. The static member function {\tt CreateFieldBody()} is called from //. the {\tt Parse()} member function and is responsible for creating a //. {\tt DwFieldBody} object for this particular field. A typical //. scenario might go as follows: //. This member function examines the field name for this field, //. finds that it contains "To", creates a {\tt DwAddressList} object //. to contain the field body, calls the {\tt Parse()} member //. function for the {\tt DwAddressList}, and sets the {\tt DwAddressList} //. object as this {\tt DwField} object's {\tt DwFieldBody}. //. //. If you want to override the behavior of {\tt CreateFieldBody()}, //. you can do so by setting the public data member //. {\tt sCreateFieldBody} to point to your own function. //. {\tt CreateFieldBody()} first checks to see if //. {\tt sCreateFieldBody} is {\tt NULL}. If it is not, //. {\tt CreateFieldBody()} will assume that it points to a user-supplied //. function and will call that function. If it is {\tt NULL}, //. {\tt CreateFieldBody()} will call {\tt _CreateFieldBody()}, which //. actually creates the {\tt DwFieldBody} object. You may call //. {\tt _CreateFieldBody()} from your own function for fields you //. do not wish to handle. static DwFieldBody* _CreateFieldBody(const DwString& aFieldName, const DwString& aFieldBody, DwMessageComponent* aParent); //+ Var sNewField static DwField* (*sNewField)(const DwString&, DwMessageComponent*); //. If {\tt sNewField} is not {\tt NULL}, it is assumed to point //. to a user-supplied function that returns an object from a class //. derived from {\tt DwField}. //+ Var sCreateFieldBody static DwFieldBody* (*sCreateFieldBody)(const DwString& aFieldName, const DwString& aFieldBody, DwMessageComponent* aParent); //. See {\tt CreateFieldBody()}. protected: DwString mFieldNameStr; // the {\it field-name} DwString mFieldBodyStr; // the {\it field-body} DwFieldBody* mFieldBody; // pointer to the {\tt DwFieldBody} object void _SetFieldBody(DwFieldBody* aFieldBody); //. Sets the {\tt DwFieldBody} object contained by this object. This //. function differs from {\tt SetFieldBody()} in that it does not //. set the is-modified flag. private: const DwField* mNext; static const char* const sClassName; public: virtual void PrintDebugInfo(std::ostream& aStrm, int aDepth=0) const; //. This virtual function, inherited from {\tt DwMessageComponent}, //. prints debugging information about this object to {\tt aStrm}. //. It will also call {\tt PrintDebugInfo()} for any of its child //. components down to a level of {\tt aDepth}. //. //. This member function is available only in the debug version of //. the library. virtual void CheckInvariants() const; //. Aborts if one of the invariants of the object fails. Use this //. member function to track down bugs. //. //. This member function is available only in the debug version of //. the library. protected: void _PrintDebugInfo(std::ostream& aStrm) const; }; #endif