wxWidgets/include/wx/html/htmlpars.h
2007-10-05 22:56:55 +00:00

302 lines
11 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: htmlpars.h
// Purpose: wxHtmlParser class (generic parser)
// Author: Vaclav Slavik
// RCS-ID: $Id$
// Copyright: (c) 1999 Vaclav Slavik
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_HTMLPARS_H_
#define _WX_HTMLPARS_H_
#include "wx/defs.h"
#if wxUSE_HTML
#include "wx/html/htmltag.h"
#include "wx/filesys.h"
#include "wx/hashmap.h"
#include "wx/hashset.h"
#include "wx/vector.h"
#include "wx/fontenc.h"
class WXDLLIMPEXP_FWD_BASE wxMBConv;
class WXDLLIMPEXP_FWD_HTML wxHtmlParser;
class WXDLLIMPEXP_FWD_HTML wxHtmlTagHandler;
class WXDLLIMPEXP_FWD_HTML wxHtmlEntitiesParser;
class wxHtmlTextPieces;
class wxHtmlParserState;
WX_DECLARE_HASH_SET_WITH_DECL(wxHtmlTagHandler*,
wxPointerHash, wxPointerEqual,
wxHtmlTagHandlersSet,
class WXDLLIMPEXP_HTML);
WX_DECLARE_STRING_HASH_MAP_WITH_DECL(wxHtmlTagHandler*,
wxHtmlTagHandlersHash,
class WXDLLIMPEXP_HTML);
enum wxHtmlURLType
{
wxHTML_URL_PAGE,
wxHTML_URL_IMAGE,
wxHTML_URL_OTHER
};
// This class handles generic parsing of HTML document : it scans
// the document and divides it into blocks of tags (where one block
// consists of starting and ending tag and of text between these
// 2 tags.
class WXDLLIMPEXP_HTML wxHtmlParser : public wxObject
{
DECLARE_ABSTRACT_CLASS(wxHtmlParser)
public:
wxHtmlParser();
virtual ~wxHtmlParser();
// Sets the class which will be used for opening files
void SetFS(wxFileSystem *fs) { m_FS = fs; }
wxFileSystem* GetFS() const { return m_FS; }
// Opens file if the parser is allowed to open given URL (may be forbidden
// for security reasons)
virtual wxFSFile *OpenURL(wxHtmlURLType type, const wxString& url) const;
// You can simply call this method when you need parsed output.
// This method does these things:
// 1. call InitParser(source);
// 2. call DoParsing();
// 3. call GetProduct(); (its return value is then returned)
// 4. call DoneParser();
wxObject* Parse(const wxString& source);
// Sets the source. This must be called before running Parse() method.
virtual void InitParser(const wxString& source);
// This must be called after Parse().
virtual void DoneParser();
// May be called during parsing to immediately return from Parse().
virtual void StopParsing() { m_stopParsing = true; }
// Parses the m_Source from begin_pos to end_pos-1.
// (in noparams version it parses whole m_Source)
void DoParsing(const wxString::const_iterator& begin_pos,
const wxString::const_iterator& end_pos);
void DoParsing();
// Returns pointer to the tag at parser's current position
wxHtmlTag *GetCurrentTag() const { return m_CurTag; }
// Returns product of parsing
// Returned value is result of parsing of the part. The type of this result
// depends on internal representation in derived parser
// (see wxHtmlWinParser for details).
virtual wxObject* GetProduct() = 0;
// adds handler to the list & hash table of handlers.
virtual void AddTagHandler(wxHtmlTagHandler *handler);
// Forces the handler to handle additional tags (not returned by GetSupportedTags).
// The handler should already be in use by this parser.
// Example: you want to parse following pseudo-html structure:
// <myitems>
// <it name="one" value="1">
// <it name="two" value="2">
// </myitems>
// <it> This last it has different meaning, we don't want it to be parsed by myitems handler!
// handler can handle only 'myitems' (e.g. its GetSupportedTags returns "MYITEMS")
// you can call PushTagHandler(handler, "IT") when you find <myitems>
// and call PopTagHandler() when you find </myitems>
void PushTagHandler(wxHtmlTagHandler *handler, const wxString& tags);
// Restores state before last call to PushTagHandler
void PopTagHandler();
const wxString* GetSource() {return m_Source;}
void SetSource(const wxString& src);
// Sets HTML source and remembers current parser's state so that it can
// later be restored. This is useful for on-line modifications of
// HTML source (for example, <pre> handler replaces spaces with &nbsp;
// and newlines with <br>)
virtual void SetSourceAndSaveState(const wxString& src);
// Restores parser's state from stack or returns false if the stack is
// empty
virtual bool RestoreState();
// Returns HTML source inside the element (i.e. between the starting
// and ending tag)
wxString GetInnerSource(const wxHtmlTag& tag);
// Parses HTML string 'markup' and extracts charset info from <meta> tag
// if present. Returns empty string if the tag is missing.
// For wxHTML's internal use.
static wxString ExtractCharsetInformation(const wxString& markup);
// Returns entity parser object, used to substitute HTML &entities;
wxHtmlEntitiesParser *GetEntitiesParser() const { return m_entitiesParser; }
// Returns true if the tag starting at the given position is a comment tag
//
// p should point to '<' character and is modified to point to the closing
// '>' of the end comment tag if this is indeed a comment
static bool
SkipCommentTag(wxString::const_iterator& p, wxString::const_iterator end);
protected:
// DOM structure
void CreateDOMTree();
void DestroyDOMTree();
void CreateDOMSubTree(wxHtmlTag *cur,
const wxString::const_iterator& begin_pos,
const wxString::const_iterator& end_pos,
wxHtmlTagsCache *cache);
// Adds text to the output.
// This is called from Parse() and must be overriden in derived classes.
// txt is not guaranteed to be only one word. It is largest continuous part
// of text (= not broken by tags)
virtual void AddText(const wxString& txt) = 0;
// Adds tag and proceeds it. Parse() may (and usually is) called from this method.
// This is called from Parse() and may be overriden.
// Default behavior is that it looks for proper handler in m_Handlers. The tag is
// ignored if no hander is found.
// Derived class is *responsible* for filling in m_Handlers table.
virtual void AddTag(const wxHtmlTag& tag);
protected:
// DOM tree:
wxHtmlTag *m_CurTag;
wxHtmlTag *m_Tags;
wxHtmlTextPieces *m_TextPieces;
size_t m_CurTextPiece;
const wxString *m_Source;
wxHtmlParserState *m_SavedStates;
// handlers that handle particular tags. The table is accessed by
// key = tag's name.
// This attribute MUST be filled by derived class otherwise it would
// be empty and no tags would be recognized
// (see wxHtmlWinParser for details about filling it)
// m_HandlersHash is for random access based on knowledge of tag name (BR, P, etc.)
// it may (and often does) contain more references to one object
// m_HandlersList is list of all handlers and it is guaranteed to contain
// only one reference to each handler instance.
wxHtmlTagHandlersSet m_HandlersSet;
wxHtmlTagHandlersHash m_HandlersHash;
DECLARE_NO_COPY_CLASS(wxHtmlParser)
// class for opening files (file system)
wxFileSystem *m_FS;
// handlers stack used by PushTagHandler and PopTagHandler
wxVector<wxHtmlTagHandlersHash*> m_HandlersStack;
// entity parse
wxHtmlEntitiesParser *m_entitiesParser;
// flag indicating that the parser should stop
bool m_stopParsing;
};
// This class (and derived classes) cooperates with wxHtmlParser.
// Each recognized tag is passed to handler which is capable
// of handling it. Each tag is handled in 3 steps:
// 1. Handler will modifies state of parser
// (using its public methods)
// 2. Parser parses source between starting and ending tag
// 3. Handler restores original state of the parser
class WXDLLIMPEXP_HTML wxHtmlTagHandler : public wxObject
{
DECLARE_ABSTRACT_CLASS(wxHtmlTagHandler)
public:
wxHtmlTagHandler() : wxObject () { m_Parser = NULL; }
// Sets the parser.
// NOTE : each _instance_ of handler is guaranteed to be called
// only by one parser. This means you don't have to care about
// reentrancy.
virtual void SetParser(wxHtmlParser *parser)
{ m_Parser = parser; }
// Returns list of supported tags. The list is in uppercase and
// tags are delimited by ','.
// Example : "I,B,FONT,P"
// is capable of handling italic, bold, font and paragraph tags
virtual wxString GetSupportedTags() = 0;
// This is hadling core method. It does all the Steps 1-3.
// To process step 2, you can call ParseInner()
// returned value : true if it called ParseInner(),
// false etherwise
virtual bool HandleTag(const wxHtmlTag& tag) = 0;
protected:
// parses input between beginning and ending tag.
// m_Parser must be set.
void ParseInner(const wxHtmlTag& tag)
{ m_Parser->DoParsing(tag.GetBeginIter(), tag.GetEndIter1()); }
// Parses given source as if it was tag's inner code (see
// wxHtmlParser::GetInnerSource). Unlike ParseInner(), this method lets
// you specify the source code to parse. This is useful when you need to
// modify the inner text before parsing.
void ParseInnerSource(const wxString& source);
wxHtmlParser *m_Parser;
DECLARE_NO_COPY_CLASS(wxHtmlTagHandler)
};
// This class is used to parse HTML entities in strings. It can handle
// both named entities and &#xxxx entries where xxxx is Unicode code.
class WXDLLIMPEXP_HTML wxHtmlEntitiesParser : public wxObject
{
DECLARE_DYNAMIC_CLASS(wxHtmlEntitiesParser)
public:
wxHtmlEntitiesParser();
virtual ~wxHtmlEntitiesParser();
// Sets encoding of output string.
// Has no effect if wxUSE_WCHAR_T==0 or wxUSE_UNICODE==1
void SetEncoding(wxFontEncoding encoding);
// Parses entities in input and replaces them with respective characters
// (with respect to output encoding)
wxString Parse(const wxString& input) const;
// Returns character for given entity or 0 if the enity is unknown
wxChar GetEntityChar(const wxString& entity) const;
// Returns character that represents given Unicode code
#if wxUSE_UNICODE
wxChar GetCharForCode(unsigned code) const { return (wxChar)code; }
#else
wxChar GetCharForCode(unsigned code) const;
#endif
protected:
#if wxUSE_WCHAR_T && !wxUSE_UNICODE
wxMBConv *m_conv;
wxFontEncoding m_encoding;
#endif
DECLARE_NO_COPY_CLASS(wxHtmlEntitiesParser)
};
#endif
#endif // _WX_HTMLPARS_H_