src/xmlpatterns/projection/qdocumentprojector.cpp

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  41
  42 #include "qdocumentprojector_p.h"
  43
  44 QT_BEGIN_NAMESPACE
  45
  46 using namespace QPatternist;
  47
  48 DocumentProjector::DocumentProjector(const ProjectedExpression::Vector &paths,
  49                                      QAbstractXmlReceiver *const receiver) : m_paths(paths)
  50                                                                            , m_pathCount(paths.count())
  51                                                                            , m_action(ProjectedExpression::Move)
  52                                                                            , m_nodesInProcess(0)
  53                                                                            , m_receiver(receiver)
  54 {
  55     Q_ASSERT_X(paths.count() > 0, Q_FUNC_INFO,
  56                "Using DocumentProjector with no paths is an "
  57                "overhead and has also undefined behavior.");
  58     Q_ASSERT(m_receiver);
  59 }
  60
  61 void DocumentProjector::startElement(const QXmlName name)
  62 {
  63     Q_UNUSED(name);
  64
  65     switch(m_action)
  66     {
  67         case ProjectedExpression::KeepSubtree:
  68         {
  69             m_receiver->startElement(name);
  70             /* Fallthrough. */
  71         }
  72         case ProjectedExpression::Skip:
  73         {
  74             ++m_nodesInProcess;
  75             return;
  76         }
  77         default:
  78         {
  79             Q_ASSERT_X(m_action == ProjectedExpression::Move, Q_FUNC_INFO,
  80                        "We're not supposed to receive Keep here, because "
  81                        "endElement() should always end that state.");
  82
  83             for(int i = 0; i < m_pathCount; ++i)
  84             {
  85                 m_action = m_paths.at(i)->actionForElement(name, m_paths[i]);
  86
  87                 switch(m_action)
  88                 {
  89                     case ProjectedExpression::Keep:
  90                     {
  91                         m_action = ProjectedExpression::Keep;
  92                         continue;
  93                     }
  94                     case ProjectedExpression::KeepSubtree:
  95                     {
  96                         /* Ok, at least one path wanted this node. Pass it on,
  97                          * and exit. */
  98                         m_receiver->startElement(name);
  99                         ++m_nodesInProcess;
 100                         return;
 101                     }
 102                     case ProjectedExpression::Skip:
 103                     {
 104                         /* This particular path doesn't need it, but
 105                          * some other path might, so continue looping. */
 106                         continue;
 107                     }
 108                     case ProjectedExpression::Move:
 109                         Q_ASSERT_X(false, Q_FUNC_INFO, "The action functions can never return Move.");
 110                 }
 111             }
 112
 113             ++m_nodesInProcess;
 114
 115             if(m_action == ProjectedExpression::Keep)
 116                 m_receiver->startElement(name);
 117             else
 118             {
 119                 Q_ASSERT(m_action == ProjectedExpression::Skip);
 120             }
 121         }
 122     }
 123 }
 124
 125 void DocumentProjector::endElement()
 126 {
 127     if(m_action == ProjectedExpression::Keep)
 128     {
 129         Q_ASSERT(m_nodesInProcess == 1);
 130
 131         m_receiver->endElement();
 132
 133         /* We have now kept the single node, and now wants to skip
 134          * all its children. */
 135         m_action = ProjectedExpression::Skip;
 136         m_nodesInProcess = 0;
 137     }
 138     else if(m_action == ProjectedExpression::KeepSubtree)
 139     {
 140         m_receiver->endElement();
 141         --m_nodesInProcess;
 142
 143         if(m_nodesInProcess == 0)
 144         {
 145             /* We have now skipped all the children, let's do
 146              * a new path analysis. */
 147             m_action = ProjectedExpression::Move;
 148         }
 149     }
 150     else
 151     {
 152         Q_ASSERT_X(m_action == ProjectedExpression::Skip, Q_FUNC_INFO,
 153                    "We're not supposed to be in a Move action here.");
 154         /* We skip calling m_receiver's endElement() here since we're
 155          * skipping. */
 156         Q_ASSERT(m_nodesInProcess > 0);
 157         --m_nodesInProcess;
 158
 159         if(m_nodesInProcess == 0)
 160         {
 161             /* Ok, we've skipped them all, let's do something
 162              * new -- let's Move on to the next path! */
 163             m_action = ProjectedExpression::Move;
 164         }
 165     }
 166 }
 167
 168 void DocumentProjector::attribute(const QXmlName name,
 169                                   const QString &value)
 170 {
 171     Q_UNUSED(name);
 172     Q_UNUSED(value);
 173 }
 174
 175 void DocumentProjector::namespaceBinding(const QXmlName nb)
 176 {
 177     Q_UNUSED(nb);
 178 }
 179
 180 void DocumentProjector::comment(const QString &value)
 181 {
 182     Q_ASSERT_X(!value.contains(QLatin1String("--")), Q_FUNC_INFO,
 183                "Invalid input; it's the caller's responsibility to ensure the input is correct.");
 184     Q_UNUSED(value);
 185 }
 186
 187 void DocumentProjector::characters(const QString &value)
 188 {
 189     Q_UNUSED(value);
 190 }
 191
 192 void DocumentProjector::processingInstruction(const QXmlName name,
 193                                               const QString &value)
 194 {
 195     Q_ASSERT_X(!value.contains(QLatin1String("?>")), Q_FUNC_INFO,
 196                "Invalid input; it's the caller's responsibility to ensure the input is correct.");
 197     Q_UNUSED(name);
 198     Q_UNUSED(value);
 199 }
 200
 201 void DocumentProjector::item(const Item &outputItem)
 202 {
 203     Q_UNUSED(outputItem);
 204 }
 205
 206 void DocumentProjector::startDocument()
 207 {
 208 }
 209
 210 void DocumentProjector::endDocument()
 211 {
 212 }
 213
 214 QT_END_NAMESPACE