exiv2/xmpsdk/src/XMLParserAdapter.hpp

#ifndef __XMLParserAdapter_hpp__
#define __XMLParserAdapter_hpp__

// =================================================================================================
// Copyright 2005-2007 Adobe Systems Incorporated
// All Rights Reserved.
//
// NOTICE:  Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
// =================================================================================================

#include "XMP_Environment.h"	// ! Must be the first #include!
#include "XMP_Const.h"

#include <string>
#include <vector>

// =================================================================================================
// XML_Node details
//
// The XML_Nodes are used only during the XML/RDF parsing process. This presently uses an XML parser
// to create an XML tree, then a recursive descent RDF recognizer to build the corresponding XMP.
// This makes it easier to swap XML parsers and provides a clean separation of XML and RDF issues.
// The overall parsing would be faster and use less memory if the RDF recognition were done on the
// fly using a state machine. But it was much easier to write the recursive descent version. The
// current implementation is pretty fast in absolute terms, so being faster might not be crucial.
//
// Like the XMP tree, the XML tree contains vectors of pointers for down links, and offspring have
// a pointer to their parent. Unlike the XMP tree, this is an exact XML document tree. There are no
// introduced top level namespace nodes or rearrangement of the nodes..
//
// The exact state of namespaces can vary during the XML parsing, depending on the parser in use.
// By the time the RDF recognition is done though, the namespaces must be normalized. All of the
// used namespaces must be registered, this is done automatically if necessary. All of the "live"
// namespace prefixes will be unique. The ns field of an XML_Node is the namespace URI, the name
// field contains a qualified name (prefix:local). This includes default namespace mapping, the
// URI and prefix will be missing only for elements and attributes in no namespace.

class XML_Node;

typedef XML_Node *	XML_NodePtr;	// Handy for things like: XML_Node * a, b; - b is XML_Node, not XML_Node*!

enum { kRootNode = 0, kElemNode = 1, kAttrNode = 2, kCDataNode = 3, kPINode = 4 };

#define IsWhitespaceChar(ch)	( ((ch) == ' ') || ((ch) == 0x09) || ((ch) == 0x0A) || ((ch) == 0x0D) )

typedef std::vector<XML_NodePtr>		XML_NodeVector;
typedef XML_NodeVector::iterator		XML_NodePos;
typedef XML_NodeVector::const_iterator	XML_cNodePos;

#if 0	// Pattern for iterating over the children or attributes:
	for ( size_t xxNum = 0, xxLim = _node_->_offspring_.size(); xxNum < xxLim; ++xxNum ) {
		const XML_NodePtr _curr_ = _node_->_offspring_[xxNum];
	}
#endif

class XML_Node {
public:

	// Intended for lightweight internal use. Clients are expected to use the data directly.
	
	XMP_Uns8		kind;
	std::string		ns, name, value;
	size_t          nsPrefixLen;
	XML_NodePtr		parent;
	XML_NodeVector	attrs;
	XML_NodeVector	content;
	
	bool IsWhitespaceNode() const;
	bool IsLeafContentNode() const;	// An empty element or one with a single character data child node.
	bool IsEmptyLeafNode() const;

	XMP_StringPtr GetAttrValue ( XMP_StringPtr attrName ) const;
	void SetAttrValue ( XMP_StringPtr attrName, XMP_StringPtr attrValue );

	XMP_StringPtr GetLeafContentValue() const;
	void SetLeafContentValue ( XMP_StringPtr value );
	
	size_t CountNamedElements ( XMP_StringPtr nsURI, XMP_StringPtr localName ) const;	// Number of child elements with this name.
	XML_NodePtr GetNamedElement ( XMP_StringPtr nsURI, XMP_StringPtr localName, size_t which = 0 );
	
	void Dump ( std::string * buffer );
	void Serialize ( std::string * buffer );
	
	void RemoveAttrs();
	void RemoveContent();
	void ClearNode();

	XML_Node ( XML_NodePtr _parent, XMP_StringPtr _name, XMP_Uns8 _kind )
            : kind(_kind), name(_name), nsPrefixLen(0), parent(_parent) {};

	XML_Node ( XML_NodePtr _parent, const std::string & _name, XMP_Uns8 _kind )
            : kind(_kind), name(_name), nsPrefixLen(0), parent(_parent) {};

	virtual ~XML_Node() { RemoveAttrs(); RemoveContent(); };

private:

	XML_Node() : kind(0), parent(0)	{};	// ! Hidden to make sure parent pointer is always set.

};

// =================================================================================================
// Abstract base class for XML parser adapters used by the XMP toolkit.

enum { kXMLPendingInputMax = 16 };

class XMLParserAdapter {
public:

	XMLParserAdapter()
		: tree(0,"",kRootNode), rootNode(0), rootCount(0), charEncoding(XMP_OptionBits(-1)), pendingCount(0)
	{
		#if XMP_DebugBuild
			parseLog = 0;
		#endif
	};

	virtual ~XMLParserAdapter() {};
	
	virtual void ParseBuffer ( const void * buffer, size_t length, bool last ) = 0;

	XML_Node		tree;
	XML_NodeVector	parseStack;
	XML_NodePtr		rootNode;
	size_t			rootCount;

	XMP_OptionBits	charEncoding;
	size_t          pendingCount;
	unsigned char	pendingInput[kXMLPendingInputMax];	// Buffered input for character encoding checks.
	
	#if XMP_DebugBuild
		FILE * parseLog;
	#endif

};

// =================================================================================================

#endif	// __XMLParserAdapter_hpp__