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39
40#include "qcommonsequencetypes_p.h"
41#include "qcommonvalues_p.h"
42#include "qitemmappingiterator_p.h"
43#include "qpatternistlocale_p.h"
44
45#include "qtracefn_p.h"
46
47QT_BEGIN_NAMESPACE
48
49using namespace QPatternist;
50
51namespace QPatternist
52{
53 /**
54 * @short TraceCallback is a MappingCallback and takes care of
55 * the tracing of each individual item.
56 *
57 * Because Patternist must be thread safe, TraceFN creates a TraceCallback
58 * each time the function is evaluated. In other words, TraceFN, which is
59 * an Expression sub class, can't modify its members, but MappingCallback
60 * does not have this limitation since it's created on a per evaluation basis.
61 *
62 * @author Frans Englich <frans.englich@nokia.com>
63 */
64 class TraceCallback : public QSharedData
65 {
66 public:
67 typedef QExplicitlySharedDataPointer<TraceCallback> Ptr;
68
69 inline TraceCallback(const QString &msg) : m_position(0),
70 m_msg(msg)
71 {
72 }
73
74 /**
75 * Performs the actual tracing.
76 */
77 Item mapToItem(const Item &item,
78 const DynamicContext::Ptr &context)
79 {
80 QTextStream out(stderr);
81 ++m_position;
82 if(m_position == 1)
83 {
84 if(item)
85 {
86 out << qPrintable(m_msg)
87 << " : "
88 << qPrintable(item.stringValue());
89 }
90 else
91 {
92 out << qPrintable(m_msg)
93 << " : ("
94 << qPrintable(formatType(context->namePool(), CommonSequenceTypes::Empty))
95 << ")\n";
96 return Item();
97 }
98 }
99 else
100 {
101 out << qPrintable(item.stringValue())
102 << '['
103 << m_position
104 << "]\n";
105 }
106
107 return item;
108 }
109
110 private:
111 xsInteger m_position;
112 const QString m_msg;
113 };
114}
115
116Item::Iterator::Ptr TraceFN::evaluateSequence(const DynamicContext::Ptr &context) const
117{
118 const QString msg(m_operands.last()->evaluateSingleton(context).stringValue());
119
120 return makeItemMappingIterator<Item>(mapper: TraceCallback::Ptr(new TraceCallback(msg)),
121 source: m_operands.first()->evaluateSequence(context),
122 context);
123}
124
125Item TraceFN::evaluateSingleton(const DynamicContext::Ptr &context) const
126{
127 const QString msg(m_operands.last()->evaluateSingleton(context).stringValue());
128 const Item item(m_operands.first()->evaluateSingleton(context));
129
130 return TraceCallback::Ptr(new TraceCallback(msg))->mapToItem(item, context);
131}
132
133SequenceType::Ptr TraceFN::staticType() const
134{
135 return m_operands.first()->staticType();
136}
137
138QT_END_NAMESPACE
139

source code of qtxmlpatterns/src/xmlpatterns/functions/qtracefn.cpp