src/xmlpatterns/expr/qpath_p.h
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 //
       
    43 //  W A R N I N G
       
    44 //  -------------
       
    45 //
       
    46 // This file is not part of the Qt API.  It exists purely as an
       
    47 // implementation detail.  This header file may change from version to
       
    48 // version without notice, or even be removed.
       
    49 //
       
    50 // We mean it.
       
    51 
       
    52 #ifndef Patternist_Path_H
       
    53 #define Patternist_Path_H
       
    54 
       
    55 #include "qpaircontainer_p.h"
       
    56 
       
    57 QT_BEGIN_HEADER
       
    58 
       
    59 QT_BEGIN_NAMESPACE
       
    60 
       
    61 namespace QPatternist
       
    62 {
       
    63 
       
    64     /**
       
    65      * @short Implements the path expression, containing two steps, such as in <tt>html/body</tt>.
       
    66      *
       
    67      * @see <a href="http://www.w3.org/TR/xquery/#id-path-expressions">XQuery 1.0: An
       
    68      * XML Query Language, 3.2 Path Expressions</a>
       
    69      * @author Frans Englich <frans.englich@nokia.com>
       
    70      * @ingroup Patternist_expressions
       
    71      */
       
    72     class Path : public PairContainer
       
    73     {
       
    74     public:
       
    75         enum Kind
       
    76         {
       
    77             /**
       
    78              * This Path is a plain old path expression as found in XPath.
       
    79              * Sorting is performed, and atomics are disallowed as left
       
    80              * operand.
       
    81              */
       
    82             RegularPath = 1,
       
    83 
       
    84             /**
       
    85              * This Path emulates an @c xsl:for-each instruction. This means no
       
    86              * sorting of result, and atomics are allowed as left operand.
       
    87              */
       
    88             XSLTForEach,
       
    89 
       
    90             /**
       
    91              * This Path performs the iteration in an @c xsl:apply-templates
       
    92              * instruction. This means sorting, and atomics are disallowed
       
    93              * as left operand.
       
    94              */
       
    95             ForApplyTemplate
       
    96         };
       
    97 
       
    98         Path(const Expression::Ptr &operand1,
       
    99              const Expression::Ptr &operand2,
       
   100              const Kind kind = RegularPath);
       
   101 
       
   102         virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
       
   103         virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
       
   104         virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;
       
   105         inline Item::Iterator::Ptr mapToSequence(const Item &item,
       
   106                                                  const DynamicContext::Ptr &context) const;
       
   107 
       
   108         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
   109                                           const SequenceType::Ptr &reqType);
       
   110 
       
   111         virtual SequenceType::List expectedOperandTypes() const;
       
   112 
       
   113         /**
       
   114          * @returns the static type of the last step where the cardinality is multiplied with
       
   115          * the cardinality of the first step's cardinality.
       
   116          */
       
   117         virtual SequenceType::Ptr staticType() const;
       
   118 
       
   119         virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
       
   120 
       
   121         virtual Properties properties() const;
       
   122 
       
   123         virtual Expression::Ptr compress(const StaticContext::Ptr &context);
       
   124 
       
   125         /**
       
   126          * @returns the item type of the last step's static type.
       
   127          */
       
   128         virtual ItemType::Ptr newFocusType() const;
       
   129 
       
   130         virtual ID id() const;
       
   131 
       
   132         inline void setLast();
       
   133 
       
   134         inline Kind kind() const
       
   135         {
       
   136             return m_kind;
       
   137         }
       
   138 
       
   139     private:
       
   140         typedef QExplicitlySharedDataPointer<const Path> ConstPtr;
       
   141 
       
   142         /**
       
   143          * One might think this block exists for preventing multiple
       
   144          * NodeSortExpressions to be created. However, that is not an issue,
       
   145          * since NodeSortExpression optimizes this away anyway.
       
   146          *
       
   147          * The real reason is to avoid infinite recursion. When our typeCheck()
       
   148          * forwards on the type check to the just created
       
   149          * NodeSortExpression, it in turn calls typeCheck() on its child, which
       
   150          * is this Path. Rince and repeat.
       
   151          *
       
   152          * We only create node sorts when we're a regular path expression, and
       
   153          * not when standing in as a generic map expression. */
       
   154         bool        m_hasCreatedSorter;
       
   155 
       
   156         /**
       
   157          * Whether this path is the step. For instance, in <tt>a/b/c</tt>, the
       
   158          * last path has @c c as the right operand.
       
   159          */
       
   160         bool        m_isLast;
       
   161 
       
   162         bool        m_checkXPTY0018;
       
   163         const Kind  m_kind;
       
   164     };
       
   165 
       
   166     void Path::setLast()
       
   167     {
       
   168         m_isLast = true;
       
   169     }
       
   170 }
       
   171 
       
   172 QT_END_NAMESPACE
       
   173 
       
   174 QT_END_HEADER
       
   175 
       
   176 #endif