/*

 * Copyright (c) 2004-2006 Nokia Corporation and/or its subsidiary(-ies). 

 * All rights reserved.

 * This component and the accompanying materials are made available

 * under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

 * which accompanies this distribution, and is available

 * at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

 *

 * Initial Contributors:

 * Nokia Corporation - initial contribution.

 *

 * Contributors:

 *

 * Description:       Namespace node functions

 *

 */

 #ifndef XMLENGINE_NAMESPACE_H_INCLUDED

 #define XMLENGINE_NAMESPACE_H_INCLUDED

 #include "xmlengnode.h"

 /**

  *   Represents existing namespace declaration in DOM tree <b>OR</b> namespace node returned

  *   in RXmlEngNodeSet as a result of some XPath expression. 

  *

  *   All elements and attributes may have a namespace instance associated.

  *   Once put in element, a namespace declaration (instance of TXmlEngNamespace) may be 

  *   referred to by all attributes and descentants of the element (unless

  *   prefix that this namespace-to-prefix binding uses is overriden somewhere below in the document tree)

  *

  *   <b>General rules of namespace handling:</b>

  *

  * - <b>NULL</b> prefix in namespace node means NO PREFIX. ""(empty string '\\0') can be used for specifying 

  *   absense of prefix when setting it, however <b>NULL</b> will be stored and returned.

  *

  * - <b>NULL</b> value of namespace URI is legal only with <b>NULL</b> prefix and only met in 

  *   undeclaration of namespace (<i>xmlns=""</i>). <b>""</b> (empty string) can be used too, however it 

  *   will be returned as <b>NULL</b>.

  *

  * - <b>NULL</b> or <b>""</b> namespace <b>URI</b> with non-<b>NULL</b> prefix is illegal acording to the XML specification.

  *

  * - Namespace of a element is <b>default</b> if it is associated with some namespace declaration with <b>NULL</b> prefix.

  *

  * - Elements are never associated with namespace undeclarations (<b>xmlns=""</b>), instead, such elements have no

  *   namespace declaration referred to. 

  *

  * - Attributes do not have <i>default</i> namespace. Even if it is effective at element scope,

  *   default namespace declaration is not applied to element's attributes (according to the XML specification)

  *

  * - Namespace of a node (element or attribute) is <b>undefined</b> if no namespace declaration is

  *   associated with it.

  *

  * - Node with <i>undefined</i> namespace is serialized as having no prefix. In general,

  *   DOM API handles the complexity of namespace declaration handling and creates neccessary

  *   namespace declarations and undeclares default namespace. However, some node-creation methods (e.g. TXmlEngElement::AddNewElementL()) 

  *   do not ensure that created node with undefined namespace (thus, without a prefix) will 

  *   actually treated after serialization as having some <i>default</i> namespace

  *

  *   @note

  *   Namespace nodes that are result of XPath expression have following restrictions:

  *       - they cannot be used as namespace definitions, because they are not part of

  *         the DOM tree, but copies of existing namespace definitions.

  *       - namespace prefix is not available because it is not mandated by DOM Level 3 XPath module API, 

  *         so in returned copies of DOM tree, namespaces prefix strings are not preserved 

  *         and Prefix() returns NULL.

  * 

  * @lib XmlEngineDOM.lib

  * @since S60 v3.1

  */

 class TXmlEngNamespace: public TXmlEngNode

 {

   public:

     /**

      * Default constructor

      *

      * @since S60 v3.1

      */

 	inline TXmlEngNamespace();

     /**

     /**

      * Get namespace URI

      *

      * @since S60 v3.1

      * @return Namespace URI string 

      * @note "" is never returned - it is replaced with NULL

      *

      * For TXmlEngNamespace(NULL) or namespace undeclaration (xmlns=""), which are

      * treatet as <i>undefined namespace</i> returns NULL,

      * otherwise result is not a NULL string and not a "" (empty string).

      */

     IMPORT_C TPtrC8 Uri() const;

     /**

      * Get namespace prefix. 

      *

      * @since S60 v3.1

      * @return prefix that is bound in the namespace declaration

      * or NULL string for default namespace or if no binding exist

      */

     IMPORT_C TPtrC8 Prefix() const;

     /**

      * Check if namespace is default.

      *

      * @since S60 v3.1

      * @return Whether it is a definition of default namespace

      *    TRUE  -- is a default namespace (no prefix)

      *    FALSE -- not a default namespace (bound to prefix) or empty TXmlEngNamespace(NULL) instance

      */

     IMPORT_C TBool IsDefault() const;

 	/**

      * Check if namespace is undefined

 	 *

      * @since S60 v3.1

      * @return Whether the namespace is undefined

      *

      * A node's namespace is undefined if no namespace declaration associated with it.

      * @note Same as TXmlEngNode::IsNull()

      */

     IMPORT_C TBool IsUndefined() const; 

 protected:

     /**

      *   Workaround to avoid misuse of TXmlEngNode::NamespaceUri() method, which should not be

      *   applied to TXmlEngNamespace node. Since the name of the inherited method from TXmlEngNode

      *   is too similar to TXmlEngNamespace::Uri(), NamespaceUri() is disabled for direct

      *   use. 

      *   If NamespaceUri() is called on the TXmlEngNamespace object that is downcasted to TXmlEngNode, then

      *   NamespaceUri()'s result equals to result of Uri() method.

      *

      * @since S60 v3.1

      * @return NULL

      */

 	inline TPtrC8 NamespaceUri();

 protected:

     /**

      * Constructor

      *

      * @since S60 v3.1

      * @param aPtr Namespace pointer

      */

 	inline TXmlEngNamespace(void* aPtr);

     friend class TXmlEngElement;

     friend class TXmlEngNode;

 };

 #include "xmlengnamespace.inl"

 #endif /* XMLENGINE_NAMESPACE_H_INCLUDED */