ClickHouse/base/poco/XML/include/Poco/SAX/DeclHandler.h

//
// DeclHandler.h
//
// Library: XML
// Package: SAX
// Module:  SAX
//
// SAX2-ext DeclHandler Interface.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef SAX_DeclHandler_INCLUDED
#define SAX_DeclHandler_INCLUDED


#include "Poco/XML/XML.h"
#include "Poco/XML/XMLString.h"


namespace Poco
{
namespace XML
{


    class XML_API DeclHandler
    /// This is an optional extension handler for SAX2 to provide information
    /// about DTD declarations in an XML document. XML
    /// readers are not required to support this handler, and this handler is
    /// not included in the core SAX2 distribution.
    ///
    /// Note that data-related DTD declarations (unparsed entities and notations)
    /// are already reported through the DTDHandler interface.
    /// If you are using the declaration handler together with a lexical handler,
    /// all of the events will occur between the startDTD and the endDTD events.
    /// To set the DeclHandler for an XML reader, use the setProperty method
    /// with the propertyId "http://xml.org/sax/properties/declaration-handler".
    /// If the reader does not support declaration events, it will throw a
    /// SAXNotRecognizedException or a SAXNotSupportedException when you attempt to
    /// register the handler.
    {
    public:
        virtual void
        attributeDecl(const XMLString & eName, const XMLString & aName, const XMLString * valueDefault, const XMLString * value)
            = 0;
        /// Report an attribute type declaration.
        ///
        /// Only the effective (first) declaration for an attribute will be reported.
        /// The type will be one of the strings "CDATA", "ID", "IDREF", "IDREFS",
        /// "NMTOKEN", "NMTOKENS", "ENTITY", "ENTITIES", a parenthesized token group
        /// with the separator "|" and all whitespace removed, or the word "NOTATION"
        /// followed by a space followed by a parenthesized token group with all whitespace
        /// removed.
        ///
        /// The value will be the value as reported to applications, appropriately normalized
        /// and with entity and character references expanded.

        virtual void elementDecl(const XMLString & name, const XMLString & model) = 0;
        /// Report an element type declaration.
        ///
        /// The content model will consist of the string "EMPTY", the string "ANY", or a
        /// parenthesised group, optionally followed by an occurrence indicator. The model
        /// will be normalized so that all parameter entities are fully resolved and all
        /// whitespace is removed,and will include the enclosing parentheses. Other
        /// normalization (such as removing redundant parentheses or simplifying occurrence
        /// indicators) is at the discretion of the parser.

        virtual void externalEntityDecl(const XMLString & name, const XMLString * publicId, const XMLString & systemId) = 0;
        /// Report an external entity declaration.
        ///
        /// Only the effective (first) declaration for each entity will be reported.
        ///
        /// If the system identifier is a URL, the parser must resolve it fully before
        /// passing it to the application.

        virtual void internalEntityDecl(const XMLString & name, const XMLString & value) = 0;
        /// Report an internal entity declaration.
        ///
        /// Only the effective (first) declaration for each entity will be reported. All
        /// parameter entities in the value will be expanded, but general entities will not.

    protected:
        virtual ~DeclHandler();
    };


}
} // namespace Poco::XML


#endif // SAX_DeclHandler_INCLUDED