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 "htmlpars.h"
  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 WXDLLEXPORT wxMBConv;
  25 class WXDLLEXPORT wxHtmlParser;
  26 class WXDLLEXPORT wxHtmlTagHandler;
  27 class WXDLLEXPORT wxHtmlEntitiesParser;
  28
  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 class WXDLLEXPORT wxHtmlParser : public wxObject
  34 {
  35     DECLARE_ABSTRACT_CLASS(wxHtmlParser)
  36
  37 public:
  38     wxHtmlParser();
  39     virtual ~wxHtmlParser();
  40
  41     // Sets the class which will be used for opening files
  42     void SetFS(wxFileSystem *fs) { m_FS = fs; }
  43
  44     wxFileSystem* GetFS() const { return m_FS; }
  45
  46     // You can simply call this method when you need parsed output.
  47     // This method does these things:
  48     // 1. call InitParser(source);
  49     // 2. call DoParsing();
  50     // 3. call GetProduct(); (it's return value is then returned)
  51     // 4. call DoneParser();
  52     wxObject* Parse(const wxString& source);
  53
  54     // Sets the source. This must be called before running Parse() method.
  55     virtual void InitParser(const wxString& source);
  56     // This must be called after Parse().
  57     virtual void DoneParser();
  58
  59     // Parses the m_Source from begin_pos to end_pos-1.
  60     // (in noparams version it parses whole m_Source)
  61     void DoParsing(int begin_pos, int end_pos);
  62     inline void DoParsing() {DoParsing(0, m_Source.Length());};
  63
  64     // Returns product of parsing
  65     // Returned value is result of parsing of the part. The type of this result
  66     // depends on internal representation in derived parser
  67     // (see wxHtmlWinParser for details).
  68     virtual wxObject* GetProduct() = 0;
  69
  70     // adds handler to the list & hash table of handlers.
  71     virtual void AddTagHandler(wxHtmlTagHandler *handler);
  72
  73     // Forces the handler to handle additional tags (not returned by GetSupportedTags).
  74     // The handler should already be in use by this parser.
  75     // Example: you want to parse following pseudo-html structure:
  76     //   <myitems>
  77     //     <it name="one" value="1">
  78     //     <it name="two" value="2">
  79     //   </myitems>
  80     //   <it> This last it has different meaning, we don't want it to be parsed by myitems handler!
  81     // handler can handle only 'myitems' (e.g. it's GetSupportedTags returns "MYITEMS")
  82     // you can call PushTagHandler(handler, "IT") when you find <myitems>
  83     // and call PopTagHandler() when you find </myitems>
  84     void PushTagHandler(wxHtmlTagHandler *handler, wxString tags);
  85
  86     // Restores state before last call to PushTagHandler
  87     void PopTagHandler();
  88
  89     wxString* GetSource() {return &m_Source;}
  90     void SetSource(const wxString& src);
  91
  92 protected:
  93     // Adds text to the output.
  94     // This is called from Parse() and must be overriden in derived classes.
  95     // txt is not guaranteed to be only one word. It is largest continuous part of text
  96     // (= not broken by tags)
  97     // NOTE : using char* because of speed improvements
  98     virtual void AddText(const char* txt) = 0;
  99
 100     // Adds tag and proceeds it. Parse() may (and usually is) called from this method.
 101     // This is called from Parse() and may be overriden.
 102     // Default behavior is that it looks for proper handler in m_Handlers. The tag is
 103     // ignored if no hander is found.
 104     // Derived class is *responsible* for filling in m_Handlers table.
 105     virtual void AddTag(const wxHtmlTag& tag);
 106
 107     // Returns entity parser object, used to substitute HTML &entities;
 108     wxHtmlEntitiesParser *GetEntitiesParser() const { return m_entitiesParser; }
 109
 110 protected:
 111     // source being parsed
 112     wxString m_Source;
 113
 114     // tags cache, used during parsing.
 115     wxHtmlTagsCache *m_Cache;
 116     wxHashTable m_HandlersHash;
 117
 118     // handlers that handle particular tags. The table is accessed by
 119     // key = tag's name.
 120     // This attribute MUST be filled by derived class otherwise it would
 121     // be empty and no tags would be recognized
 122     // (see wxHtmlWinParser for details about filling it)
 123     // m_HandlersHash is for random access based on knowledge of tag name (BR, P, etc.)
 124     //      it may (and often does) contain more references to one object
 125     // m_HandlersList is list of all handlers and it is guaranteed to contain
 126     //      only one reference to each handler instance.
 127     wxList m_HandlersList;
 128
 129     // class for opening files (file system)
 130     wxFileSystem *m_FS;
 131     // handlers stack used by PushTagHandler and PopTagHandler
 132     wxList *m_HandlersStack;
 133
 134     // entity parse
 135     wxHtmlEntitiesParser *m_entitiesParser;
 136 };
 137
 138
 139
 140 // This class (and derived classes) cooperates with wxHtmlParser.
 141 // Each recognized tag is passed to handler which is capable
 142 // of handling it. Each tag is handled in 3 steps:
 143 // 1. Handler will modifies state of parser
 144 //    (using it's public methods)
 145 // 2. Parser parses source between starting and ending tag
 146 // 3. Handler restores original state of the parser
 147 class WXDLLEXPORT wxHtmlTagHandler : public wxObject
 148 {
 149     DECLARE_ABSTRACT_CLASS(wxHtmlTagHandler)
 150
 151 public:
 152     wxHtmlTagHandler() : wxObject () { m_Parser = NULL; }
 153
 154     // Sets the parser.
 155     // NOTE : each _instance_ of handler is guaranteed to be called
 156     // only by one parser. This means you don't have to care about
 157     // reentrancy.
 158     virtual void SetParser(wxHtmlParser *parser)
 159         { m_Parser = parser; }
 160
 161     // Returns list of supported tags. The list is in uppercase and
 162     // tags are delimited by ','.
 163     // Example : "I,B,FONT,P"
 164     //   is capable of handling italic, bold, font and paragraph tags
 165     virtual wxString GetSupportedTags() = 0;
 166
 167     // This is hadling core method. It does all the Steps 1-3.
 168     // To process step 2, you can call ParseInner()
 169     // returned value : TRUE if it called ParseInner(),
 170     //                  FALSE etherwise
 171     virtual bool HandleTag(const wxHtmlTag& tag) = 0;
 172
 173 protected:
 174     // parses input between beginning and ending tag.
 175     // m_Parser must be set.
 176     void ParseInner(const wxHtmlTag& tag)
 177         { m_Parser->DoParsing(tag.GetBeginPos(), tag.GetEndPos1()); }
 178
 179     wxHtmlParser *m_Parser;
 180 };
 181
 182
 183 // This class is used to parse HTML entities in strings. It can handle
 184 // both named entities and &#xxxx entries where xxxx is Unicode code.
 185 class WXDLLEXPORT wxHtmlEntitiesParser : public wxObject
 186 {
 187     DECLARE_DYNAMIC_CLASS(wxHtmlEntitiesParser)
 188
 189 public:
 190     wxHtmlEntitiesParser();
 191     virtual ~wxHtmlEntitiesParser();
 192
 193     // Sets encoding of output string.
 194     // Has no effect if wxUSE_WCHAR_T==0 or wxUSE_UNICODE==1
 195     void SetEncoding(wxFontEncoding encoding);
 196
 197     // Parses entities in input and replaces them with respective characters
 198     // (with respect to output encoding)
 199     wxString Parse(const wxString& input);
 200
 201 protected:
 202     wxChar GetEntityChar(const wxString& entity);
 203     wxChar GetCharForCode(unsigned code);
 204
 205 #if wxUSE_WCHAR_T && !wxUSE_UNICODE
 206     wxMBConv *m_conv;
 207     wxFontEncoding m_encoding;
 208 #endif
 209 };
 210
 211
 212 #endif
 213
 214 #endif // _WX_HTMLPARS_H_