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 #if defined(__GNUG__) && !defined(__APPLE__)
  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 #include "wx/hash.h"
  24 #include "wx/fontenc.h"
  25
  26 class WXDLLEXPORT wxMBConv;
  27 class WXDLLEXPORT wxHtmlParser;
  28 class WXDLLEXPORT wxHtmlTagHandler;
  29 class WXDLLEXPORT wxHtmlEntitiesParser;
  30
  31 class wxHtmlTextPieces;
  32 class wxHtmlParserState;
  33
  34
  35 enum wxHtmlURLType
  36 {
  37     wxHTML_URL_PAGE,
  38     wxHTML_URL_IMAGE,
  39     wxHTML_URL_OTHER
  40 };
  41
  42 // This class handles generic parsing of HTML document : it scans
  43 // the document and divide it into blocks of tags (where one block
  44 // consists of starting and ending tag and of text between these
  45 // 2 tags.
  46 class WXDLLEXPORT wxHtmlParser : public wxObject
  47 {
  48     DECLARE_ABSTRACT_CLASS(wxHtmlParser)
  49
  50 public:
  51     wxHtmlParser();
  52     virtual ~wxHtmlParser();
  53
  54     // Sets the class which will be used for opening files
  55     void SetFS(wxFileSystem *fs) { m_FS = fs; }
  56
  57     wxFileSystem* GetFS() const { return m_FS; }
  58
  59     // Opens file if the parser is allowed to open given URL (may be forbidden
  60     // for security reasons)
  61     virtual wxFSFile *OpenURL(wxHtmlURLType type, const wxString& url) const;
  62
  63     // You can simply call this method when you need parsed output.
  64     // This method does these things:
  65     // 1. call InitParser(source);
  66     // 2. call DoParsing();
  67     // 3. call GetProduct(); (it's return value is then returned)
  68     // 4. call DoneParser();
  69     wxObject* Parse(const wxString& source);
  70
  71     // Sets the source. This must be called before running Parse() method.
  72     virtual void InitParser(const wxString& source);
  73     // This must be called after Parse().
  74     virtual void DoneParser();
  75
  76     // Parses the m_Source from begin_pos to end_pos-1.
  77     // (in noparams version it parses whole m_Source)
  78     void DoParsing(int begin_pos, int end_pos);
  79     void DoParsing();
  80
  81     // Returns pointer to the tag at parser's current position
  82     wxHtmlTag *GetCurrentTag() const { return m_CurTag; }
  83
  84     // Returns product of parsing
  85     // Returned value is result of parsing of the part. The type of this result
  86     // depends on internal representation in derived parser
  87     // (see wxHtmlWinParser for details).
  88     virtual wxObject* GetProduct() = 0;
  89
  90     // adds handler to the list & hash table of handlers.
  91     virtual void AddTagHandler(wxHtmlTagHandler *handler);
  92
  93     // Forces the handler to handle additional tags (not returned by GetSupportedTags).
  94     // The handler should already be in use by this parser.
  95     // Example: you want to parse following pseudo-html structure:
  96     //   <myitems>
  97     //     <it name="one" value="1">
  98     //     <it name="two" value="2">
  99     //   </myitems>
 100     //   <it> This last it has different meaning, we don't want it to be parsed by myitems handler!
 101     // handler can handle only 'myitems' (e.g. it's GetSupportedTags returns "MYITEMS")
 102     // you can call PushTagHandler(handler, "IT") when you find <myitems>
 103     // and call PopTagHandler() when you find </myitems>
 104     void PushTagHandler(wxHtmlTagHandler *handler, wxString tags);
 105
 106     // Restores state before last call to PushTagHandler
 107     void PopTagHandler();
 108
 109     wxString* GetSource() {return &m_Source;}
 110     void SetSource(const wxString& src);
 111
 112     // Sets HTML source and remebers current parser's state so that it can
 113     // later be restored. This is useful for on-line modifications of
 114     // HTML source (for example, <pre> handler replaces spaces with &nbsp;
 115     // and newlines with <br>)
 116     virtual void SetSourceAndSaveState(const wxString& src);
 117     // Restores parser's state from stack or returns FALSE if the stack is
 118     // empty
 119     virtual bool RestoreState();
 120
 121 protected:
 122     // DOM structure
 123     void CreateDOMTree();
 124     void DestroyDOMTree();
 125     void CreateDOMSubTree(wxHtmlTag *cur,
 126                           int begin_pos, int end_pos,
 127                           wxHtmlTagsCache *cache);
 128
 129     // Adds text to the output.
 130     // This is called from Parse() and must be overriden in derived classes.
 131     // txt is not guaranteed to be only one word. It is largest continuous part of text
 132     // (= not broken by tags)
 133     // NOTE : using char* because of speed improvements
 134     virtual void AddText(const wxChar* txt) = 0;
 135
 136     // Adds tag and proceeds it. Parse() may (and usually is) called from this method.
 137     // This is called from Parse() and may be overriden.
 138     // Default behavior is that it looks for proper handler in m_Handlers. The tag is
 139     // ignored if no hander is found.
 140     // Derived class is *responsible* for filling in m_Handlers table.
 141     virtual void AddTag(const wxHtmlTag& tag);
 142
 143     // Returns entity parser object, used to substitute HTML &entities;
 144     wxHtmlEntitiesParser *GetEntitiesParser() const { return m_entitiesParser; }
 145
 146 protected:
 147     // DOM tree:
 148     wxHtmlTag *m_CurTag;
 149     wxHtmlTag *m_Tags;
 150     wxHtmlTextPieces *m_TextPieces;
 151     size_t m_CurTextPiece;
 152
 153     wxString m_Source;
 154
 155     wxHtmlParserState *m_SavedStates;
 156
 157     // handlers that handle particular tags. The table is accessed by
 158     // key = tag's name.
 159     // This attribute MUST be filled by derived class otherwise it would
 160     // be empty and no tags would be recognized
 161     // (see wxHtmlWinParser for details about filling it)
 162     // m_HandlersHash is for random access based on knowledge of tag name (BR, P, etc.)
 163     //      it may (and often does) contain more references to one object
 164     // m_HandlersList is list of all handlers and it is guaranteed to contain
 165     //      only one reference to each handler instance.
 166     wxList m_HandlersList;
 167     wxHashTable m_HandlersHash;
 168
 169     // class for opening files (file system)
 170     wxFileSystem *m_FS;
 171     // handlers stack used by PushTagHandler and PopTagHandler
 172     wxList *m_HandlersStack;
 173
 174     // entity parse
 175     wxHtmlEntitiesParser *m_entitiesParser;
 176 };
 177
 178
 179
 180 // This class (and derived classes) cooperates with wxHtmlParser.
 181 // Each recognized tag is passed to handler which is capable
 182 // of handling it. Each tag is handled in 3 steps:
 183 // 1. Handler will modifies state of parser
 184 //    (using it's public methods)
 185 // 2. Parser parses source between starting and ending tag
 186 // 3. Handler restores original state of the parser
 187 class WXDLLEXPORT wxHtmlTagHandler : public wxObject
 188 {
 189     DECLARE_ABSTRACT_CLASS(wxHtmlTagHandler)
 190
 191 public:
 192     wxHtmlTagHandler() : wxObject () { m_Parser = NULL; }
 193
 194     // Sets the parser.
 195     // NOTE : each _instance_ of handler is guaranteed to be called
 196     // only by one parser. This means you don't have to care about
 197     // reentrancy.
 198     virtual void SetParser(wxHtmlParser *parser)
 199         { m_Parser = parser; }
 200
 201     // Returns list of supported tags. The list is in uppercase and
 202     // tags are delimited by ','.
 203     // Example : "I,B,FONT,P"
 204     //   is capable of handling italic, bold, font and paragraph tags
 205     virtual wxString GetSupportedTags() = 0;
 206
 207     // This is hadling core method. It does all the Steps 1-3.
 208     // To process step 2, you can call ParseInner()
 209     // returned value : TRUE if it called ParseInner(),
 210     //                  FALSE etherwise
 211     virtual bool HandleTag(const wxHtmlTag& tag) = 0;
 212
 213 protected:
 214     // parses input between beginning and ending tag.
 215     // m_Parser must be set.
 216     void ParseInner(const wxHtmlTag& tag)
 217         { m_Parser->DoParsing(tag.GetBeginPos(), tag.GetEndPos1()); }
 218
 219     wxHtmlParser *m_Parser;
 220 };
 221
 222
 223 // This class is used to parse HTML entities in strings. It can handle
 224 // both named entities and &#xxxx entries where xxxx is Unicode code.
 225 class WXDLLEXPORT wxHtmlEntitiesParser : public wxObject
 226 {
 227     DECLARE_DYNAMIC_CLASS(wxHtmlEntitiesParser)
 228
 229 public:
 230     wxHtmlEntitiesParser();
 231     virtual ~wxHtmlEntitiesParser();
 232
 233     // Sets encoding of output string.
 234     // Has no effect if wxUSE_WCHAR_T==0 or wxUSE_UNICODE==1
 235     void SetEncoding(wxFontEncoding encoding);
 236
 237     // Parses entities in input and replaces them with respective characters
 238     // (with respect to output encoding)
 239     wxString Parse(const wxString& input);
 240
 241     // Returns character for given entity or 0 if the enity is unknown
 242     wxChar GetEntityChar(const wxString& entity);
 243
 244     // Returns character that represents given Unicode code
 245     wxChar GetCharForCode(unsigned code);
 246
 247 protected:
 248 #if wxUSE_WCHAR_T && !wxUSE_UNICODE
 249     wxMBConv *m_conv;
 250     wxFontEncoding m_encoding;
 251 #endif
 252 };
 253
 254
 255 #endif
 256
 257 #endif // _WX_HTMLPARS_H_