1 // Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // XPath evaluation context declaration

    15 //

    16 

    17 

    18 

    19 /**

    20  @file

    21  @internalComponent

    22  @released

    23 */

    24 #ifndef XMLENGXPATHEVALCTXT_IMPL_H

    25 #define XMLENGXPATHEVALCTXT_IMPL_H

    26 

    27 #include <xml/dom/xmlengxpathevaluationcontext.h>

    28 #include <libxml2_xpathinternals.h>

    29 

    30 /**

    31  * XPath evaluation context

    32  *

    33  */

    34 class TXmlEngXPathEvaluationContextImpl: public MXmlEngXPathEvaluationContext

    35     {

    36 public:

    37 	/**

    38      * Constructor

    39 	 * 

    40 	 * @param aContext Pointer to XPath parser context

    41 	 * @param aArgCount Number of arguments

    42 	 */

    43     TXmlEngXPathEvaluationContextImpl(xmlXPathParserContextPtr aContext, TUint aArgCount)

    44         : iContext(aContext), 

    45           iArgCount(aArgCount), 

    46           iCurrentResult(NULL),

    47           iOOM(EFalse) {}

    48 

    49 	/**

    50      * Get number of arguments provided

    51      *

    52      * @return Number of arguments provided

    53      *

    54      * @note 

    55      *    The implementation of extension function should not check

    56      *    that ArgCount() returns value in the range [ MinArity() ; MaxArity() ]

    57      *    - the function is called iif the statement holds:<br>

    58      *      <b>MinArity()</b>  =<  <i>arg.count</i>  =< <b>MaxArity()</b> 

    59      */

    60     TUint ArgCount();

    61 

    62 	/**

    63      * Retrieves arguments by index (zero-based)

    64      *

    65      * @return N-th argument of the function

    66      *

    67      * @note

    68      *    - Argument index starts at 0

    69      *    - Returned result should not be freed

    70      */

    71     const RXmlEngXPathResult Argument(TUint aIndex);

    72 

    73 	/**

    74      * Get the result written so far.

    75      * 

    76      * @return Result evaluated by the function so far.

    77      *

    78      * Initially, function result is undefined. It can be changed

    79      * by SetResult() functions for a boolean, string or number values 

    80      * or by combined use of InitializeNodeSetResult() and AppendToResult() methods

    81      */

    82     const RXmlEngXPathResult Result();

    83 

    84 	/**

    85      * Sets a NODESET type of the result (floating-point number): an empty

    86      * instance of NodeSet is created.

    87      *

    88      * The node set is to be filled up by methods AppendToResult(TXmlEngNode) and AppendToResult(RXmlEngNodeSet)

    89      * This method replaces any existing prepared result so far 

    90      * (even an initialized already node set)

    91      * @see AppendToResult(TXmlEngNode), AppendToResult(RXmlEngNodeSet)

    92      *

    93      */ 

    94     void  InitializeNodeSetResult();     

    95 

    96 	/**

    97      * Appends a node to the node set result.

    98      * @note InitializeNodeSetResult() should be called prior any call to 

    99      *       AppendToResult(TXmlEngNode) or AppendToResult(RXmlEngNodeSet)

   100      *

   101      * @param aNode Node that should be add

   102      */ 

   103     void  AppendToResult(const TXmlEngNode aNode);

   104     void  AppendToResult(const TXmlEngNamespace aAppendedNsNode, const TXmlEngElement aNsParentNode);

   105 	/**

   106     * Appends a node set to the node set result. Nodes are merged into resulting node set.

   107     * @note InitializeNodeSetResult() should be called prior any call to 

   108     *       AppendToResult(TXmlEngNode) or AppendToResult(RXmlEngNodeSet)

   109     *

   110     * @param aNodeSet Nodes that should be add

   111     */

   112     void  AppendToResult(const RXmlEngNodeSet aNodeSet);

   113 

   114 	/**

   115      * Sets a NUMBER type of the result (a floating-point number)

   116      *

   117      * @param aNumber New number

   118      */ 

   119     void  SetResult(TReal aNumber);

   120 

   121 	/**

   122      * Sets a BOOLEAN type of the result 

   123      *

   124      * @param aBoolean New value

   125      */

   126     void  SetResult(TBool aBoolean);

   127 

   128 	/**

   129      * Sets a STRING type of the result

   130      *

   131      * @param aString New string value

   132      */

   133     void  SetResultL(const TDesC8& aString);

   134 

   135 	/**

   136      * Gets data specified in RXmlEngXPathExpression::SetExtendedContext(void*) method

   137      * for the expression currently being evaluated.

   138      *

   139      */ 

   140     void* ExtendedContext();

   141 

   142     /**

   143      * Allocates memory for function result

   144      * 

   145      * @return TRUE is succeeded, FALSE if OOM has happened

   146      */

   147     TBool Initialize();

   148 

   149 private:

   150 	/** XPath parser */

   151     xmlXPathParserContextPtr iContext;

   152 	/** Arguments count */

   153     TUint iArgCount;

   154 	/** XPath object */

   155     xmlXPathObjectPtr iCurrentResult;    

   156 	/** OOM flag */

   157     TBool iOOM;

   158     };

   159 

   160 #endif /* XMLENGXPATHEVALCTXT_IMPL_H */