src/xmlpatterns/projection/qdocumentprojector.cpp

   1 /****************************************************************************
   2 **
   3 ** Copyright (C) 2011 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 ** GNU Lesser General Public License Usage
  11 ** This file may be used under the terms of the GNU Lesser General Public
  12 ** License version 2.1 as published by the Free Software Foundation and
  13 ** appearing in the file LICENSE.LGPL included in the packaging of this
  14 ** file. Please review the following information to ensure the GNU Lesser
  15 ** General Public License version 2.1 requirements will be met:
  16 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
  17 **
  18 ** In addition, as a special exception, Nokia gives you certain additional
  19 ** rights. These rights are described in the Nokia Qt LGPL Exception
  20 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
  21 **
  22 ** GNU General Public License Usage
  23 ** Alternatively, this file may be used under the terms of the GNU General
  24 ** Public License version 3.0 as published by the Free Software Foundation
  25 ** and appearing in the file LICENSE.GPL included in the packaging of this
  26 ** file. Please review the following information to ensure the GNU General
  27 ** Public License version 3.0 requirements will be met:
  28 ** http://www.gnu.org/copyleft/gpl.html.
  29 **
  30 ** Other Usage
  31 ** Alternatively, this file may be used in accordance with the terms and
  32 ** conditions contained in a signed written agreement between you and Nokia.
  33 **
  34 **
  35 **
  36 **
  37 **
  38 ** $QT_END_LICENSE$
  39 **
  40 ****************************************************************************/
  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