1 //============================================================================= 2 // File: field.h 3 // Contents: Declarations for DwField 4 // Maintainer: Doug Sauder <dwsauder@fwb.gulf.net> 5 // WWW: http://www.fwb.gulf.net/~dwsauder/mimepp.html 6 // $Revision: 1.9 $ 7 // $Date: 2002/04/22 09:45:44 $ 8 // 9 // Copyright (c) 1996, 1997 Douglas W. Sauder 10 // All rights reserved. 11 // 12 // IN NO EVENT SHALL DOUGLAS W. SAUDER BE LIABLE TO ANY PARTY FOR DIRECT, 13 // INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF 14 // THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF DOUGLAS W. SAUDER 15 // HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 16 // 17 // DOUGLAS W. SAUDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT 18 // NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 19 // PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" 20 // BASIS, AND DOUGLAS W. SAUDER HAS NO OBLIGATION TO PROVIDE MAINTENANCE, 21 // SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 22 // 23 //============================================================================= 24 25 #ifndef DW_FIELD_H 26 #define DW_FIELD_H 27 28 #include <iostream> 29 30 #ifndef DW_CONFIG_H 31 #include <mimelib/config.h> 32 #endif 33 34 #ifndef DW_STRING_H 35 #include <mimelib/string.h> 36 #endif 37 38 #ifndef DW_MSGCMP_H 39 #include <mimelib/msgcmp.h> 40 #endif 41 42 class DwHeaders; 43 class DwFieldBody; 44 45 //============================================================================= 46 //+ Name DwField -- Class representing a MIME header field 47 //+ Description 48 //. {\tt DwField} represents a header field as described in RFC-822. 49 //. According to RFC-822, a field contains a field name and a field body. 50 //. In MIME++, a {\tt DwField} contains three elements: a {\tt DwString} 51 //. that contains its field name, a {\tt DwString} that contains its 52 //. field body, and a {\tt DwFieldBody} object that contains a broken-down 53 //. (that is, parsed) version of its field body. 54 //. 55 //. In the tree (broken-down) representation of message, a {\tt DwField} 56 //. object is always an intermediate node, having a parent node and a single 57 //. child node. The parent node is the {\tt DwHeaders} object that contains 58 //. it. The child node is the {\tt DwFieldBody} object it contains. 59 //. 60 //. To get and set the field name, use the member functions 61 //. {\tt FieldNameStr()} and {\tt SetFieldNameStr()}. 62 //. To get and set the field body, use the member functions 63 //. {\tt FieldBodyStr()} and {\tt SetFieldBodyStr()}. 64 //. To get and set the {\tt DwFieldBody} object, use {\tt FieldBody()} 65 //. and {\tt SetFieldBody()}. 66 //. 67 //. A {\tt DwField} object can be included in a list of {\tt DwField} 68 //. objects; usually this is the list of {\tt DwField} objects maintained 69 //. by its parent {\tt DwHeaders} object. To get the next {\tt DwField} 70 //. object in a list, use the member function {\tt Next()}. 71 //============================================================================= 72 // Last updated 1997-08-23 73 //+ Noentry ~DwField _CreateFieldBody mFieldNameStr mFieldBodyStr 74 //+ Noentry mFieldBody _PrintDebugInfo 75 76 class DW_EXPORT DwField : public DwMessageComponent { 77 78 friend class DwHeaders; 79 80 public: 81 82 DwField(); 83 DwField(const DwField& aField); 84 DwField(const DwString& aStr, DwMessageComponent* aParent=0); 85 //. The first constructor is the default constructor, which sets the 86 //. {\tt DwField} object's field name and field body to the empty 87 //. string, set its parent to {\tt NULL}, and sets its {\tt DwFieldBody} 88 //. object to {\tt NULL}. 89 //. 90 //. The second constructor is the copy constructor, which performs 91 //. a deep copy of {\tt aField}. 92 //. The parent of the new {\tt DwField} object is set to {\tt NULL}. 93 //. 94 //. The third constructor copies {\tt aStr} to the {\tt DwField} 95 //. object's string representation and sets {\tt aParent} as its parent. 96 //. The virtual member function {\tt Parse()} should be called immediately 97 //. after this constructor in order to parse the string representation. 98 //. Unless it is {\tt NULL}, {\tt aParent} should point to an object of 99 //. a class derived from {\tt DwHeaders}. 100 101 virtual ~DwField(); 102 103 const DwField& operator = (const DwField& aField); 104 //. This is the assignment operator, which performs a deep copy of 105 //. {\tt aField}. The parent node of the {\tt DwField} object 106 //. is not changed. 107 108 virtual void Parse(); 109 //. This virtual function, inherited from {\tt DwMessageComponent}, 110 //. executes the parse method for {\tt DwField} objects. The parse 111 //. method creates or updates the broken-down representation from the 112 //. string representation. For {\tt DwField} objects, the parse method 113 //. parses the string representation, sets the values of the field 114 //. name string and the field body string, and creates an instance 115 //. of the appropriate subclass of {\tt DwFieldBody}. This member 116 //. function also calls the {\tt Parse()} member function of its 117 //. contained {\tt DwFieldBody} object. 118 //. 119 //. You should call this member function after you set or modify the 120 //. string representation, and before you access the field name, the 121 //. field body, or the contained {\tt DwFieldBody} object. 122 //. 123 //. This function clears the is-modified flag. 124 125 virtual void Assemble(); 126 //. This virtual function, inherited from {\tt DwMessageComponent}, 127 //. executes the assemble method for {\tt DwField} objects. The 128 //. assemble method creates or updates the string representation from 129 //. the broken-down representation. In more concrete terms, the 130 //. assemble method builds the string representation from the field 131 //. name and the string representation of the contained {\tt DwFieldBody} 132 //. object. This member function calls the {\tt Assemble()} member 133 //. function of its contained {\tt DwFieldBody} object. 134 //. 135 //. You should call this member function after you modify either the 136 //. field name or the contained {\tt DwFieldBody} object, and before 137 //. you retrieve the string representation. 138 //. 139 //. This function clears the is-modified flag. 140 141 virtual DwMessageComponent* Clone() const; 142 //. This virtual function, inherited from {\tt DwMessageComponent}, 143 //. creates a new {\tt DwField} on the free store that has the same 144 //. value as this {\tt DwField} object. The basic idea is that of 145 //. a virtual copy constructor. 146 147 DwFieldBody* FieldBody() const; 148 //. Returns the {\tt DwFieldBody} object contained by this {\tt DwField} 149 //. object. If there is no field body, {\tt NULL} will be returned. 150 151 const DwString& FieldNameStr() const; 152 //. Returns the field name of this header field as a string. 153 154 const DwString& FieldBodyStr() const; 155 //. Returns the field body of this header field as a string. 156 157 DwField* Next() const; 158 //. Returns the next {\tt DwField} object following this 159 //. {\tt DwField} object in the list contained in a {\tt DwHeaders}. 160 //. Returns {\tt NULL} if this object is last in the list. 161 162 void SetFieldBody(DwFieldBody* aFieldBody); 163 //. Sets the {\tt DwFieldBody} object contained by this object. 164 165 void SetFieldNameStr(const DwString& aStr); 166 //. Sets the field name of this header field. 167 168 void SetFieldBodyStr(const DwString& aStr); 169 //. Sets the field body of this header field. 170 171 void SetNext(const DwField* aField); 172 //. This {\it advanced} function sets {\tt aField} as the next field 173 //. following this field in the list of fields contained in the headers. 174 //. Since {\tt DwHeaders} contains member functions for adding 175 //. {\tt DwField} objects to its list, this function should be 176 //. avoided for most applications. 177 178 static DwField* NewField(const DwString& aStr, 179 DwMessageComponent* aParent); 180 //. Creates a new {\tt DwField} object on the free store. 181 //. If the static data member {\tt sNewField} is {\tt NULL}, 182 //. this member function will create a new {\tt DwField} 183 //. and return it. Otherwise, {\tt NewField()} will call 184 //. the user-supplied function pointed to by {\tt sNewField}, 185 //. which is assumed to return an object from a class derived from 186 //. {\tt DwField}, and return that object. 187 188 static DwFieldBody* CreateFieldBody(const DwString& aFieldName, 189 const DwString& aFieldBody, DwMessageComponent* aParent); 190 //. The static member function {\tt CreateFieldBody()} is called from 191 //. the {\tt Parse()} member function and is responsible for creating a 192 //. {\tt DwFieldBody} object for this particular field. A typical 193 //. scenario might go as follows: 194 //. This member function examines the field name for this field, 195 //. finds that it contains "To", creates a {\tt DwAddressList} object 196 //. to contain the field body, calls the {\tt Parse()} member 197 //. function for the {\tt DwAddressList}, and sets the {\tt DwAddressList} 198 //. object as this {\tt DwField} object's {\tt DwFieldBody}. 199 //. 200 //. If you want to override the behavior of {\tt CreateFieldBody()}, 201 //. you can do so by setting the public data member 202 //. {\tt sCreateFieldBody} to point to your own function. 203 //. {\tt CreateFieldBody()} first checks to see if 204 //. {\tt sCreateFieldBody} is {\tt NULL}. If it is not, 205 //. {\tt CreateFieldBody()} will assume that it points to a user-supplied 206 //. function and will call that function. If it is {\tt NULL}, 207 //. {\tt CreateFieldBody()} will call {\tt _CreateFieldBody()}, which 208 //. actually creates the {\tt DwFieldBody} object. You may call 209 //. {\tt _CreateFieldBody()} from your own function for fields you 210 //. do not wish to handle. 211 212 static DwFieldBody* _CreateFieldBody(const DwString& aFieldName, 213 const DwString& aFieldBody, DwMessageComponent* aParent); 214 215 //+ Var sNewField 216 static DwField* (*sNewField)(const DwString&, DwMessageComponent*); 217 //. If {\tt sNewField} is not {\tt NULL}, it is assumed to point 218 //. to a user-supplied function that returns an object from a class 219 //. derived from {\tt DwField}. 220 221 //+ Var sCreateFieldBody 222 static DwFieldBody* (*sCreateFieldBody)(const DwString& aFieldName, 223 const DwString& aFieldBody, DwMessageComponent* aParent); 224 //. See {\tt CreateFieldBody()}. 225 226 protected: 227 228 DwString mFieldNameStr; 229 // the {\it field-name} 230 231 DwString mFieldBodyStr; 232 // the {\it field-body} 233 234 DwFieldBody* mFieldBody; 235 // pointer to the {\tt DwFieldBody} object 236 237 void _SetFieldBody(DwFieldBody* aFieldBody); 238 //. Sets the {\tt DwFieldBody} object contained by this object. This 239 //. function differs from {\tt SetFieldBody()} in that it does not 240 //. set the is-modified flag. 241 242 private: 243 244 const DwField* mNext; 245 static const char* const sClassName; 246 247 public: 248 249 virtual void PrintDebugInfo(std::ostream& aStrm, int aDepth=0) const; 250 //. This virtual function, inherited from {\tt DwMessageComponent}, 251 //. prints debugging information about this object to {\tt aStrm}. 252 //. It will also call {\tt PrintDebugInfo()} for any of its child 253 //. components down to a level of {\tt aDepth}. 254 //. 255 //. This member function is available only in the debug version of 256 //. the library. 257 258 virtual void CheckInvariants() const; 259 //. Aborts if one of the invariants of the object fails. Use this 260 //. member function to track down bugs. 261 //. 262 //. This member function is available only in the debug version of 263 //. the library. 264 265 protected: 266 267 void _PrintDebugInfo(std::ostream& aStrm) const; 268 269 }; 270 271 #endif 272