source: XMLIO_V2/external/include/Poco/SAX/NamespaceSupport.h @ 80

//
// NamespaceSupport.h
//
// $Id: //poco/1.3/XML/include/Poco/SAX/NamespaceSupport.h#1 $
//
// Library: XML
// Package: SAX
// Module:  SAX
//
// Namespace support for SAX2.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef SAX_NamespaceSupport_INCLUDED
#define SAX_NamespaceSupport_INCLUDED


#include "Poco/XML/XML.h"
#include "Poco/XML/XMLString.h"
#include <set>
#include <map>
#include <vector>


namespace Poco {
namespace XML {


class XML_API NamespaceSupport
        /// Encapsulate Namespace logic for use by SAX drivers. 
        /// This class encapsulates the logic of Namespace processing: 
        /// it tracks the declarations currently in force for each context and
        /// automatically processes qualified XML 1.0 names into their Namespace 
        /// parts; it can also be used in reverse for generating
        /// XML 1.0 from Namespaces.
        /// Namespace support objects are reusable, but the reset method 
        /// must be invoked between each session.
{
public:
        typedef std::set<XMLString> PrefixSet;

        NamespaceSupport();
                /// Creates a NamespaceSupport object.
                
        ~NamespaceSupport();
                /// Destroys a NamespaceSupport object.
        
        bool declarePrefix(const XMLString& prefix, const XMLString& namespaceURI);
                /// Declare a Namespace prefix. All prefixes must be declared before they are
                /// referenced. For example, a SAX driver (parser) would scan an element's attributes
                /// in two passes: first for namespace declarations, then a second pass using
                /// processName() to interpret prefixes against (potentially redefined) prefixes.
                /// 
                /// This method declares a prefix in the current Namespace context; the prefix
                /// will remain in force until this context is popped, unless it is shadowed
                /// in a descendant context.
                /// 
                /// To declare the default element Namespace, use the empty string as the prefix.
                /// 
                /// Note that you must not declare a prefix after you've pushed and popped another
                /// Namespace context, or treated the declarations phase as complete by processing
                /// a prefixed name.
                ///
                /// Returns true if the prefix was legal, false otherwise.
        
        bool undeclarePrefix(const XMLString& prefix);
                /// Remove the given namespace prefix.
        
        void getDeclaredPrefixes(PrefixSet& prefixes) const;
                /// Return an enumeration of all prefixes declared in this context.
                /// 
                /// The empty (default) prefix will be included in this enumeration; note that
                /// this behaviour differs from that of getPrefix(java.lang.String) and getPrefixes().

        const XMLString& getPrefix(const XMLString& namespaceURI) const;
                /// Return one of the prefixes mapped to a Namespace URI.
                /// 
                /// If more than one prefix is currently mapped to the same URI, this method
                /// will make an arbitrary selection; if you want all of the prefixes, use the
                /// getPrefixes() method instead.

        bool isMapped(const XMLString& namespaceURI) const;
                /// Returns true if the given namespaceURI has been mapped to a prefix,
                /// false otherwise.

        void getPrefixes(PrefixSet& prefixes) const;
                /// Return an enumeration of all prefixes whose declarations are active in the
                /// current context. This includes declarations from parent contexts that have
                /// not been overridden.
                /// 
                /// Note: if there is a default prefix, it will not be returned in this enumeration;
                /// check for the default prefix using the getURI with an argument of "".

        void getPrefixes(const XMLString& namespaceURI, PrefixSet& prefixes) const;
                /// Return an enumeration of all prefixes for a given URI whose declarations
                /// are active in the current context. This includes declarations from parent
                /// contexts that have not been overridden.
                /// 
                /// This method returns prefixes mapped to a specific Namespace URI. The xml:
                /// prefix will be included. If you want only one prefix that's mapped to the
                /// Namespace URI, and you don't care which one you get, use the getPrefix() method
                /// instead.
                /// 
                /// Note: the empty (default) prefix is never included in this enumeration;
                /// to check for the presence of a default Namespace, use the getURI() method
                /// with an argument of "".

        const XMLString& getURI(const XMLString& prefix) const;
                /// Look up a prefix and get the currently-mapped Namespace URI.
                /// 
                /// This method looks up the prefix in the current context. Use the empty string
                /// ("") for the default Namespace.

        void pushContext();
                /// Start a new Namespace context. The new context will automatically inherit
                /// the declarations of its parent context, but it will also keep track of which
                /// declarations were made within this context.
                /// 
                /// Event callback code should start a new context once per element. This means
                /// being ready to call this in either of two places. For elements that don't
                /// include namespace declarations, the ContentHandler::startElement() callback
                /// is the right place. For elements with such a declaration, it'd done in the
                /// first ContentHandler::startPrefixMapping() callback. A boolean flag can be
                /// used to track whether a context has been started yet. When either of those
                /// methods is called, it checks the flag to see if a new context needs to be
                /// started. If so, it starts the context and sets the flag. After 
                /// ContentHandler::startElement() does that, it always clears the flag.
                /// 
                /// Normally, SAX drivers would push a new context at the beginning of each
                /// XML element. Then they perform a first pass over the attributes to process
                /// all namespace declarations, making ContentHandler::startPrefixMapping() callbacks.
                /// Then a second pass is made, to determine the namespace-qualified names for
                /// all attributes and for the element name. Finally all the information for
                /// the ContentHandler::startElement() callback is available, so it can then
                /// be made.
                /// 
                /// The Namespace support object always starts with a base context already in
                /// force: in this context, only the "xml" prefix is declared.

        void popContext();
                /// Revert to the previous Namespace context.
                /// 
                /// Normally, you should pop the context at the end of each XML element. After
                /// popping the context, all Namespace prefix mappings that were previously
                /// in force are restored.
                /// 
                /// You must not attempt to declare additional Namespace prefixes after popping
                /// a context, unless you push another context first.

        bool processName(const XMLString& qname, XMLString& namespaceURI, XMLString& localName, bool isAttribute) const;
                /// Process a raw XML 1.0 name. 
                /// This method processes a raw XML 1.0 name in the current context 
                /// by removing the prefix and looking it up among the
                /// prefixes currently declared. The result will be returned in
                /// namespaceURI and localName.
                /// If the raw name has a prefix that has not been declared, then the return
                /// value will be false, otherwise true.
                ///
                /// Note that attribute names are processed differently than element names: 
                /// an unprefixed element name will received the
                /// default Namespace (if any), while an unprefixed element name will not.

        void reset();
                /// Reset this Namespace support object for reuse.
                /// 
                /// It is necessary to invoke this method before reusing the Namespace support
                /// object for a new session. If namespace declaration URIs are to be supported,
                /// that flag must also be set to a non-default value.
                /// Reset this Namespace support object for reuse.

        static const XMLString XML_NAMESPACE;
        static const XMLString XML_NAMESPACE_PREFIX;
        static const XMLString XMLNS_NAMESPACE;
        static const XMLString XMLNS_NAMESPACE_PREFIX;

private:
        NamespaceSupport(const NamespaceSupport&);
        NamespaceSupport& operator = (const NamespaceSupport&);

        typedef std::map<XMLString, XMLString> Context;
        typedef std::vector<Context> ContextVec;
        
        ContextVec _contexts;

        static const XMLString EMPTY_STRING;
};


} } // namespace Poco::XML


#endif // SAX_NamespaceSupport_INCLUDED