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     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.

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    41 

    42 #include "qcommonsequencetypes_p.h"

    43 #include "qcommonvalues_p.h"

    44 #include "qitemmappingiterator_p.h"

    45 #include "qpatternistlocale_p.h"

    46 

    47 #include "qtracefn_p.h"

    48 

    49 QT_BEGIN_NAMESPACE

    50 

    51 using namespace QPatternist;

    52 

    53 namespace QPatternist

    54 {

    55     /**

    56      * @short TraceCallback is a MappingCallback and takes care of

    57      * the tracing of each individual item.

    58      *

    59      * Because Patternist must be thread safe, TraceFN creates a TraceCallback

    60      * each time the function is evaluated. In other words, TraceFN, which is

    61      * an Expression sub class, can't modify its members, but MappingCallback

    62      * does not have this limitation since it's created on a per evaluation basis.

    63      *

    64      * @author Frans Englich <frans.englich@nokia.com>

    65      */

    66     class TraceCallback : public QSharedData

    67     {

    68     public:

    69         typedef QExplicitlySharedDataPointer<TraceCallback> Ptr;

    70 

    71         inline TraceCallback(const QString &msg) : m_position(0),

    72                                                    m_msg(msg)

    73         {

    74         }

    75 

    76         /**

    77          * Performs the actual tracing.

    78          */

    79         Item mapToItem(const Item &item,

    80                             const DynamicContext::Ptr &context)

    81         {

    82             QTextStream out(stderr);

    83             ++m_position;

    84             if(m_position == 1)

    85             {

    86                 if(item)

    87                 {

    88                     out << qPrintable(m_msg)

    89                         << " : "

    90                         << qPrintable(item.stringValue());

    91                 }

    92                 else

    93                 {

    94                     out << qPrintable(m_msg)

    95                         << " : ("

    96                         << qPrintable(formatType(context->namePool(), CommonSequenceTypes::Empty))

    97                         << ")\n";

    98                     return Item();

    99                 }

   100             }

   101             else

   102             {

   103                 out << qPrintable(item.stringValue())

   104                     << '['

   105                     << m_position

   106                     << "]\n";

   107             }

   108 

   109             return item;

   110         }

   111 

   112     private:

   113         xsInteger m_position;

   114         const QString m_msg;

   115     };

   116 }

   117 

   118 Item::Iterator::Ptr TraceFN::evaluateSequence(const DynamicContext::Ptr &context) const

   119 {

   120     const QString msg(m_operands.last()->evaluateSingleton(context).stringValue());

   121 

   122     return makeItemMappingIterator<Item>(TraceCallback::Ptr(new TraceCallback(msg)),

   123                                               m_operands.first()->evaluateSequence(context),

   124                                               context);

   125 }

   126 

   127 Item TraceFN::evaluateSingleton(const DynamicContext::Ptr &context) const

   128 {

   129     const QString msg(m_operands.last()->evaluateSingleton(context).stringValue());

   130     const Item item(m_operands.first()->evaluateSingleton(context));

   131 

   132     return TraceCallback::Ptr(new TraceCallback(msg))->mapToItem(item, context);

   133 }

   134 

   135 SequenceType::Ptr TraceFN::staticType() const

   136 {

   137     return m_operands.first()->staticType();

   138 }

   139 

   140 QT_END_NAMESPACE