include/wx/html/htmlpars.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        htmlpars.h
   3 // Purpose:     wxHtmlParser class (generic parser)
   4 // Author:      Vaclav Slavik
   5 // RCS-ID:      $Id$
   6 // Copyright:   (c) 1999 Vaclav Slavik
   7 // Licence:     wxWindows Licence
   8 /////////////////////////////////////////////////////////////////////////////
   9
  10
  11 #ifndef _WX_HTMLPARS_H_
  12 #define _WX_HTMLPARS_H_
  13
  14 #ifdef __GNUG__
  15 #pragma interface
  16 #endif
  17
  18 #include "wx/defs.h"
  19 #if wxUSE_HTML
  20
  21 #include "wx/html/htmltag.h"
  22 #include "wx/filesys.h"
  23
  24 class wxHtmlParser;
  25 class wxHtmlTagHandler;
  26
  27 //--------------------------------------------------------------------------------
  28 // wxHtmlParser
  29 //                  This class handles generic parsing of HTML document : it scans
  30 //                  the document and divide it into blocks of tags (where one block
  31 //                  consists of starting and ending tag and of text between these
  32 //                  2 tags.
  33 //--------------------------------------------------------------------------------
  34
  35 class WXDLLEXPORT wxHtmlParser : public wxObject
  36 {
  37     DECLARE_ABSTRACT_CLASS(wxHtmlParser)
  38
  39     public:
  40         wxHtmlParser() : wxObject(), m_HandlersHash(wxKEY_STRING) {m_FS = NULL; m_Cache = NULL; m_HandlersStack = NULL;}
  41         virtual ~wxHtmlParser();
  42
  43         void SetFS(wxFileSystem *fs) {m_FS = fs;}
  44                 // Sets the class which will be used for opening files
  45         wxFileSystem* GetFS() const {return m_FS;}
  46
  47         wxObject* Parse(const wxString& source);
  48                 // You can simply call this method when you need parsed output.
  49                 // This method does these things:
  50                 // 1. call InitParser(source);
  51                 // 2. call DoParsing();
  52                 // 3. call GetProduct(); (it's return value is then returned)
  53                 // 4. call DoneParser();
  54
  55         virtual void InitParser(const wxString& source);
  56                 // Sets the source. This must be called before running Parse() method.
  57         virtual void DoneParser();
  58                 // This must be called after Parse().
  59
  60         void DoParsing(int begin_pos, int end_pos);
  61         inline void DoParsing() {DoParsing(0, m_Source.Length());};
  62                 // Parses the m_Source from begin_pos to end_pos-1.
  63                 // (in noparams version it parses whole m_Source)
  64
  65         virtual wxObject* GetProduct() = 0;
  66                 // Returns product of parsing
  67                 // Returned value is result of parsing of the part. The type of this result
  68                 // depends on internal representation in derived parser
  69                 // (see wxHtmlWinParser for details).
  70
  71         virtual void AddTagHandler(wxHtmlTagHandler *handler);
  72                 // adds handler to the list & hash table of handlers.
  73
  74         void PushTagHandler(wxHtmlTagHandler *handler, wxString tags);
  75                 // Forces the handler to handle additional tags (not returned by GetSupportedTags).
  76                 // The handler should already be in use by this parser.
  77                 // Example: you want to parse following pseudo-html structure:
  78                 //   <myitems>
  79                 //     <it name="one" value="1">
  80                 //     <it name="two" value="2">
  81                 //   </myitems>
  82                 //   <it> This last it has different meaning, we don't want it to be parsed by myitems handler!
  83                 // handler can handle only 'myitems' (e.g. it's GetSupportedTags returns "MYITEMS")
  84                 // you can call PushTagHandler(handler, "IT") when you find <myitems>
  85                 // and call PopTagHandler() when you find </myitems>
  86
  87         void PopTagHandler();
  88                 // Restores state before last call to PushTagHandler
  89
  90         wxString* GetSource() {return &m_Source;}
  91
  92         virtual wxList* GetTempData() {return NULL;}
  93                 // this method returns list of wxObjects that represents
  94                 // all data allocated by the parser. These can't be freeded
  95                 // by destructor because they must be valid as long as
  96                 // GetProduct's return value is valid - the caller must
  97                 // explicitly call delete MyParser -> GetTempData() to free
  98                 // the memory
  99                 // (this method always sets the list to delete its contents)
 100
 101     protected:
 102
 103         virtual void AddText(const char* txt) = 0;
 104                 // Adds text to the output.
 105                 // This is called from Parse() and must be overriden in derived classes.
 106                 // txt is not guaranteed to be only one word. It is largest continuous part of text
 107                 // (= not broken by tags)
 108                 // NOTE : using char* because of speed improvements
 109
 110         virtual void AddTag(const wxHtmlTag& tag);
 111                 // Adds tag and proceeds it. Parse() may (and usually is) called from this method.
 112                 // This is called from Parse() and may be overriden.
 113                 // Default behavior is that it looks for proper handler in m_Handlers. The tag is
 114                 // ignored if no hander is found.
 115                 // Derived class is *responsible* for filling in m_Handlers table.
 116
 117
 118     protected:
 119         wxString m_Source;
 120                 // source being parsed
 121         wxHtmlTagsCache *m_Cache;
 122                 // tags cache, used during parsing.
 123         wxHashTable m_HandlersHash;
 124         wxList m_HandlersList;
 125                 // handlers that handle particular tags. The table is accessed by
 126                 // key = tag's name.
 127                 // This attribute MUST be filled by derived class otherwise it would
 128                 // be empty and no tags would be recognized
 129                 // (see wxHtmlWinParser for details about filling it)
 130                 // m_HandlersHash is for random access based on knowledge of tag name (BR, P, etc.)
 131                 //      it may (and often does) contain more references to one object
 132                 // m_HandlersList is list of all handlers and it is guaranteed to contain
 133                 //      only one reference to each handler instance.
 134         wxFileSystem *m_FS;
 135                 // class for opening files (file system)
 136         wxList *m_HandlersStack;
 137                 // handlers stack used by PushTagHandler and PopTagHandler
 138
 139 };
 140
 141
 142
 143
 144
 145
 146 //--------------------------------------------------------------------------------
 147 // wxHtmlTagHandler
 148 //                  This class (and derived classes) cooperates with wxHtmlParser.
 149 //                  Each recognized tag is passed to handler which is capable
 150 //                  of handling it. Each tag is handled in 3 steps:
 151 //                  1. Handler will modifies state of parser
 152 //                    (using it's public methods)
 153 //                  2. Parser parses source between starting and ending tag
 154 //                  3. Handler restores original state of the parser
 155 //--------------------------------------------------------------------------------
 156
 157 class WXDLLEXPORT wxHtmlTagHandler : public wxObject
 158 {
 159     DECLARE_ABSTRACT_CLASS(wxHtmlTagHandler)
 160
 161     protected:
 162         wxHtmlParser *m_Parser;
 163
 164     public:
 165         wxHtmlTagHandler() : wxObject () {m_Parser = NULL;};
 166
 167         virtual void SetParser(wxHtmlParser *parser) {m_Parser = parser;}
 168                 // Sets the parser.
 169                 // NOTE : each _instance_ of handler is guaranteed to be called
 170                 // only by one parser. This means you don't have to care about
 171                 // reentrancy.
 172
 173         virtual wxString GetSupportedTags() = 0;
 174                 // Returns list of supported tags. The list is in uppercase and
 175                 // tags are delimited by ','.
 176                 // Example : "I,B,FONT,P"
 177                 //   is capable of handling italic, bold, font and paragraph tags
 178
 179         virtual bool HandleTag(const wxHtmlTag& tag) = 0;
 180                 // This is hadling core method. It does all the Steps 1-3.
 181                 // To process step 2, you can call ParseInner()
 182                 // returned value : TRUE if it called ParseInner(),
 183                 //                  FALSE etherwise
 184
 185     protected:
 186         void ParseInner(const wxHtmlTag& tag) {m_Parser -> DoParsing(tag.GetBeginPos(), tag.GetEndPos1());}
 187                 // parses input between beginning and ending tag.
 188                 // m_Parser must be set.
 189 };
 190
 191
 192
 193
 194 #endif
 195
 196 #endif // _WX_HTMLPARS_H_