src/xmlpatterns/expr/qapplytemplate.cpp
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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.
       
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    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
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    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
       
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    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.
       
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    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include <QtDebug>
       
    43 
       
    44 #include "qaxisstep_p.h"
       
    45 #include "qcommonsequencetypes_p.h"
       
    46 #include "qcommonvalues_p.h"
       
    47 #include "qitemmappingiterator_p.h"
       
    48 #include "qsequencemappingiterator_p.h"
       
    49 #include "qpatternistlocale_p.h"
       
    50 
       
    51 #include "qapplytemplate_p.h"
       
    52 
       
    53 QT_BEGIN_NAMESPACE
       
    54 
       
    55 using namespace QPatternist;
       
    56 
       
    57 ApplyTemplate::ApplyTemplate(const TemplateMode::Ptr &mode,
       
    58                              const WithParam::Hash &withParams,
       
    59                              const TemplateMode::Ptr &defaultMode) : TemplateInvoker(withParams)
       
    60                                                                    , m_mode(mode)
       
    61                                                                    , m_defaultMode(defaultMode)
       
    62 {
       
    63     Q_ASSERT_X(m_mode || m_defaultMode, Q_FUNC_INFO,
       
    64                "Either a mode, or the default mode must be supplied.");
       
    65 }
       
    66 
       
    67 Item ApplyTemplate::mapToItem(const QXmlNodeModelIndex &node,
       
    68                               const DynamicContext::Ptr &) const
       
    69 {
       
    70     return Item(node);
       
    71 }
       
    72 
       
    73 Item::Iterator::Ptr ApplyTemplate::mapToSequence(const Item &item,
       
    74                                                  const DynamicContext::Ptr &context) const
       
    75 {
       
    76     Q_UNUSED(item);
       
    77     return evaluateSequence(context);
       
    78 }
       
    79 
       
    80 TemplateMode::Ptr ApplyTemplate::effectiveMode(const DynamicContext::Ptr &context) const
       
    81 {
       
    82     if(m_mode)
       
    83         return m_mode;
       
    84     else
       
    85     {
       
    86         const TemplateMode::Ptr currentMode(context->currentTemplateMode());
       
    87 
       
    88         if(currentMode)
       
    89             return currentMode;
       
    90         else
       
    91             return m_defaultMode;
       
    92     }
       
    93 }
       
    94 
       
    95 Template::Ptr ApplyTemplate::findTemplate(const DynamicContext::Ptr &context,
       
    96                                           const TemplateMode::Ptr &templateMode) const
       
    97 {
       
    98     const int count = templateMode->templatePatterns.count();
       
    99     Template::Ptr result;
       
   100     /* It's redundant to initialize these values, but it suppresses false
       
   101      * positives with GCC. */
       
   102     PatternPriority priority = 0;
       
   103     TemplatePattern::ID id = -1;
       
   104 
       
   105     /* Possible optimization: detecting ambiguous rule matches could be forked off to a
       
   106      * low prioirity thread. */
       
   107     for(int i = 0; i < count; ++i)
       
   108     {
       
   109         const TemplatePattern::Ptr &candidate = templateMode->templatePatterns.at(i);
       
   110         if(candidate->matchPattern()->evaluateEBV(context))
       
   111         {
       
   112             if(result)
       
   113             {
       
   114                 if(   candidate->id() != id
       
   115                    && candidate->priority() == priority
       
   116                    && candidate->templateTarget()->importPrecedence ==
       
   117                                                         result->importPrecedence)
       
   118                 {
       
   119                     context->error(QtXmlPatterns::tr("Ambiguous rule match."),
       
   120                                    ReportContext::XTRE0540, this);
       
   121                 }
       
   122                 else
       
   123                     break;
       
   124             }
       
   125             else
       
   126             {
       
   127                 result = candidate->templateTarget();
       
   128                 priority = candidate->priority();
       
   129                 id = candidate->id();
       
   130             }
       
   131         }
       
   132     }
       
   133 
       
   134     return result;
       
   135 }
       
   136 
       
   137 Item::Iterator::Ptr ApplyTemplate::evaluateSequence(const DynamicContext::Ptr &context) const
       
   138 {
       
   139     const TemplateMode::Ptr templateMode(effectiveMode(context));
       
   140     const Template::Ptr &templateMatch = findTemplate(context, templateMode);
       
   141 
       
   142     if(templateMatch)
       
   143         return templateMatch->body->evaluateSequence(templateMatch->createContext(this, context, false));
       
   144     else
       
   145     {
       
   146         /* None of our templates matched. Proceed with a built-in. */
       
   147         const Item current(context->contextItem());
       
   148         // TODO it can be an atomic value?
       
   149         const QXmlNodeModelIndex::NodeKind kind(current.asNode().kind());
       
   150 
       
   151         if(kind == QXmlNodeModelIndex::Element || kind == QXmlNodeModelIndex::Document)
       
   152         {
       
   153             pDebug() << "No template match, using builtin template for element() | document-node()";
       
   154 
       
   155             const Item::Iterator::Ptr focusIterator(makeItemMappingIterator<Item>(ConstPtr(this),
       
   156                                                                                   current.asNode().iterate(QXmlNodeModelIndex::AxisChild),
       
   157                                                                                   context));
       
   158 
       
   159             const DynamicContext::Ptr focus(context->createFocus());
       
   160             focus->setFocusIterator(focusIterator);
       
   161             return makeSequenceMappingIterator<Item>(ConstPtr(this), focusIterator, focus);
       
   162         }
       
   163         return CommonValues::emptyIterator;
       
   164     }
       
   165 }
       
   166 
       
   167 Expression::Ptr ApplyTemplate::compress(const StaticContext::Ptr &context)
       
   168 {
       
   169     /* If we have a mode, we will never need the default mode. */
       
   170     if(m_mode)
       
   171         m_defaultMode.reset();
       
   172 
       
   173     return TemplateInvoker::compress(context);
       
   174 }
       
   175 
       
   176 SequenceType::Ptr ApplyTemplate::staticType() const
       
   177 {
       
   178     return CommonSequenceTypes::ZeroOrMoreItems;
       
   179 }
       
   180 
       
   181 ExpressionVisitorResult::Ptr ApplyTemplate::accept(const ExpressionVisitor::Ptr &visitor) const
       
   182 {
       
   183     return visitor->visit(this);
       
   184 }
       
   185 
       
   186 Expression::Properties ApplyTemplate::properties() const
       
   187 {
       
   188     return RequiresFocus | DisableElimination;
       
   189 }
       
   190 
       
   191 bool ApplyTemplate::configureRecursion(const CallTargetDescription::Ptr &sign)
       
   192 {
       
   193     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
       
   194     Q_UNUSED(sign);
       
   195     return false;
       
   196 }
       
   197 
       
   198 Expression::Ptr ApplyTemplate::body() const
       
   199 {
       
   200     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
       
   201     return Expression::Ptr();
       
   202 }
       
   203 
       
   204 CallTargetDescription::Ptr ApplyTemplate::callTargetDescription() const
       
   205 {
       
   206     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
       
   207     return CallTargetDescription::Ptr();
       
   208 }
       
   209 
       
   210 QT_END_NAMESPACE