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XMLLoadSave.h

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00001 //-*-c++-*-
00002 #ifndef INCLUDED_XMLLoadSave_h_
00003 #define INCLUDED_XMLLoadSave_h_
00004 
00005 #include "LoadSave.h"
00006 
00007 //!@name libxml2 forward declarations
00008 //!forward declaration of the libxml2 struct of the same name
00009 extern "C" {
00010   struct _xmlNode;
00011   struct _xmlDoc;
00012   struct _xmlAttr;
00013   typedef _xmlNode xmlNode;
00014   typedef _xmlDoc xmlDoc;
00015   typedef _xmlAttr xmlAttr;
00016 }
00017 //@}
00018 
00019 //! XMLLoadSave adds functions for XML format serialization, although if you write binary LoadSave functions as well, you can do either
00020 class XMLLoadSave : public LoadSave {
00021 public:
00022   
00023   //! an exception to be thrown when a bad XML file is parsed, allows file position information to be passed to the user
00024   class bad_format : public std::exception {
00025   public:
00026     //!constructor
00027     bad_format(xmlNode * node) throw() : std::exception(), node_(node), msg_("invalid format in plist") {}
00028     //!constructor
00029     bad_format(xmlNode * node, const std::string& msg) throw() : std::exception(), node_(node), msg_(msg) {}
00030     //!copy constructor
00031     bad_format(const bad_format& bf) : std::exception(bf), node_(bf.node_), msg_(bf.msg_) {}
00032     //!assignment
00033     bad_format& operator=(const bad_format& bf) { std::exception::operator=(bf); node_=bf.node_; msg_=bf.msg_; return *this; }
00034     virtual ~bad_format() throw() {} //!< destructor
00035     virtual const char * what() const throw() { return msg_.c_str(); } //!< standard interface for getting the exception's message string
00036     virtual xmlNode * getNode() const throw() { return node_; } //!< returns the xmlNode at which the error occurred
00037   protected:
00038     xmlNode * node_; //!< the node of the error
00039     std::string msg_; //!< message regarding the type of error
00040   };
00041   
00042   XMLLoadSave(); //!< constructor
00043   XMLLoadSave(const XMLLoadSave& xls); //!< copy constructor
00044   XMLLoadSave& operator=(const XMLLoadSave& xls); //!< assignment operator
00045   virtual ~XMLLoadSave(); //!< destructor
00046   
00047   //! This is called when the subclass needs to update its values from those values in the parse tree
00048   /*! @a node is the current node in the tree -- it may be the root, but it
00049    *  may also be a subnode within the tree if a recursive structure is used */
00050   virtual void loadXML(xmlNode* node)=0;
00051   //! This is called when XMLLoadSave needs to have the subclass update values in the tree currently in memory -- may already be filled out by previous contents
00052   /*! @a node is the current node in the tree -- it may be the root, but it
00053    *  may also be a subnode within the tree if a recursive structure is used */
00054   virtual void saveXML(xmlNode * node) const=0;
00055   
00056   virtual unsigned int getBinSize() const;
00057   virtual unsigned int loadBuffer(const char buf[], unsigned int len);
00058   virtual unsigned int saveBuffer(char buf[], unsigned int len) const;
00059 
00060   virtual unsigned int loadFile(const char* filename);
00061   virtual unsigned int saveFile(const char* filename) const;
00062   
00063   virtual unsigned int loadFileStream(FILE* f);
00064   virtual unsigned int saveFileStream(FILE* f) const;
00065   
00066   //! resets the parse tree currently in memory so that a future save will write a "fresh" copy from scratch.
00067   /*! You may also want to call this in order to save memory after a Load so that
00068    *  the parse tree information isn't retained in memory if you don't care about
00069    *  retaining the file formatting */
00070   virtual void clearParseTree();
00071 
00072   //! assigns a parse tree which you have obtained from some other source
00073   /*! This doesn't update the contents of the subclass's values.  The values in
00074    *  @a doc will be overwritten by those in the subclass on the next Save.
00075    *  If you wish to have the subclass's values updated from @a doc, call
00076    *  readParseTree() after calling this. */
00077   virtual void setParseTree(xmlDoc* doc) const;
00078   
00079   //! returns the current parse tree, either from a previous Load, Save, or setParseTree()
00080   virtual xmlDoc* getParseTree() const { return xmldocument; }
00081   
00082   //! calls loadXML with the root of the current parse tree
00083   virtual void readParseTree();
00084   //! calls saveXML with the root of the current parse tree
00085   virtual void writeParseTree();
00086   
00087   //! allows you to set the compression level used by libxml2 -- this corresponds to the compression level setting of zlib, i.e. 0-9
00088   virtual void setCompression(int level);
00089   //! returns the current compression level setting used by libxml2 (via zlib)
00090   virtual int getCompression() const { return compressionLevel; }
00091   
00092 protected:
00093   //! returns the root element of the xml document
00094   virtual xmlNode* FindRootXMLElement(xmlDoc* doc) const;
00095 
00096   //! cleans up after an error occurs and sends a message to cerr
00097   void reportError(const std::string& context, const bad_format& err) const;
00098 
00099   //! called by libxml2 when it's ready for more data to be read from the source (in this case, a file)
00100   static int fileReadCallback(void* f,char* buf, int len);
00101 
00102   //! called by libxml2 when it's done reading data
00103   static int fileCloseCallback(void* f);
00104 
00105   //! returns the next element following @a cur
00106   /*! You should call this with node->next, otherwise you'll just keep getting the same node back again */
00107   static xmlNode* skipToElement(xmlNode* cur);
00108 
00109   //! returns the next element following @a cur; comment is set to the concatination of any comments is encountered in the interim
00110   /*! You should call this with node->next, otherwise you'll just keep getting the same node back again */
00111   static xmlNode* skipToElement(xmlNode* cur, std::string& comment);
00112 
00113   //! the cached xml parse tree -- contains additional formatting information such as white space and comments
00114   mutable xmlDoc* xmldocument;
00115 
00116   //! the current compression level, or level to be used for the next save
00117   int compressionLevel;
00118   
00119   //! if true, the saved document will use automatic indenting and formatting
00120   bool autoFormat;
00121 
00122   //static const char * const base64="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
00123   
00124   //! allows automatic (de)initialization of libxml when the first or last XMLLoadSave class is created or destroyed
00125   class AutoInit {
00126   public:
00127     AutoInit(); //!< if #libxmlrefc is 0, calls libxml2 initialization and configuration functions
00128     ~AutoInit(); //!< if #libxmlrefc is 1, calls libxml2 destruction functions
00129   protected:
00130     static unsigned int libxmlrefc; //!< current number of XMLLoadSave subclass instances
00131   } libxmlInit; //!< allows tracking of libxml usage so the library can be initialized and destructed automatically
00132   
00133 };
00134 
00135 /*! @file
00136  * @brief 
00137  * @author Ethan Tira-Thompson (ejt) (Creator)
00138  *
00139  * $Author: ejt $
00140  * $Name: tekkotsu-4_0 $
00141  * $Revision: 1.9 $
00142  * $State: Exp $
00143  * $Date: 2007/01/30 22:56:20 $
00144  */
00145 
00146 #endif

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