src/xmlpatterns/expr/qgenericpredicate.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/expr/qgenericpredicate.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,218 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtXmlPatterns module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qabstractfloat_p.h"
+#include "qboolean_p.h"
+#include "qbuiltintypes_p.h"
+#include "qcommonsequencetypes_p.h"
+#include "qemptysequence_p.h"
+#include "qfirstitempredicate_p.h"
+#include "qgenericsequencetype_p.h"
+#include "qitemmappingiterator_p.h"
+#include "qliteral_p.h"
+#include "qpatternistlocale_p.h"
+#include "qtruthpredicate_p.h"
+
+#include "qgenericpredicate_p.h"
+
+QT_BEGIN_NAMESPACE
+
+using namespace QPatternist;
+
+GenericPredicate::GenericPredicate(const Expression::Ptr &sourceExpression,
+                                   const Expression::Ptr &predicate) : PairContainer(sourceExpression,
+                                                                                     predicate)
+{
+}
+
+Expression::Ptr GenericPredicate::create(const Expression::Ptr &sourceExpression,
+                                         const Expression::Ptr &predicateExpression,
+                                         const StaticContext::Ptr &context,
+                                         const QSourceLocation &location)
+{
+    Q_ASSERT(sourceExpression);
+    Q_ASSERT(predicateExpression);
+    Q_ASSERT(context);
+    const ItemType::Ptr type(predicateExpression->staticType()->itemType());
+
+    if(predicateExpression->is(IDIntegerValue) &&
+       predicateExpression->as<Literal>()->item().as<Numeric>()->toInteger() == 1)
+    { /* Handle [1] */
+        return createFirstItem(sourceExpression);
+    }
+    else if(BuiltinTypes::numeric->xdtTypeMatches(type))
+    { /* A numeric predicate, other than [1]. */
+        /* TODO at somepoint we'll return a specialized expr here, NumericPredicate or so.
+         * Dependency analysis is a bit tricky, since the contained expression can depend on
+         * some loop component. */
+        return Expression::Ptr(new GenericPredicate(sourceExpression, predicateExpression));
+    }
+    else if(*CommonSequenceTypes::Empty == *type)
+    {
+        return EmptySequence::create(predicateExpression.data(), context);
+    }
+    else if(*BuiltinTypes::item == *type ||
+            *BuiltinTypes::xsAnyAtomicType == *type)
+    {
+        /* The type couldn't be narrowed at compile time, so we use
+         * a generic predicate. This check is before the CommonSequenceTypes::EBV check,
+         * because the latter matches these types as well. */
+        return Expression::Ptr(new GenericPredicate(sourceExpression, predicateExpression));
+    }
+    else if(CommonSequenceTypes::EBV->itemType()->xdtTypeMatches(type))
+    {
+        return Expression::Ptr(new TruthPredicate(sourceExpression, predicateExpression));
+    }
+    else
+    {
+        context->error(QtXmlPatterns::tr("A value of type %1 cannot be a "
+                                         "predicate. A predicate must have "
+                                         "either a numeric type or an "
+                                         "Effective Boolean Value type.")
+                       .arg(formatType(context->namePool(),
+                                       sourceExpression->staticType())),
+                       ReportContext::FORG0006, location);
+        return Expression::Ptr(); /* Silence compiler warning. */
+    }
+}
+
+Expression::Ptr GenericPredicate::createFirstItem(const Expression::Ptr &sourceExpression)
+
+{
+    return Expression::Ptr(new FirstItemPredicate(sourceExpression));
+}
+
+Item GenericPredicate::mapToItem(const Item &item,
+                                 const DynamicContext::Ptr &context) const
+{
+    const Item::Iterator::Ptr it(m_operand2->evaluateSequence(context));
+    const Item pcateItem(it->next());
+
+    if(!pcateItem)
+        return Item(); /* The predicate evaluated to the empty sequence */
+    else if(pcateItem.isNode())
+        return item;
+    /* Ok, now it must be an AtomicValue */
+    else if(BuiltinTypes::numeric->xdtTypeMatches(pcateItem.type()))
+    { /* It's a positional predicate. */
+        if(it->next())
+        {
+            context->error(QtXmlPatterns::tr("A positional predicate must "
+                                             "evaluate to a single numeric "
+                                             "value."),
+                              ReportContext::FORG0006, this);
+            return Item();
+        }
+
+        if(Double::isEqual(static_cast<xsDouble>(context->contextPosition()),
+                           pcateItem.as<Numeric>()->toDouble()))
+        {
+            return item;
+        }
+        else
+            return Item();
+    }
+    else if(Boolean::evaluateEBV(pcateItem, it, context)) /* It's a truth predicate. */
+        return item;
+    else
+        return Item();
+}
+
+Item::Iterator::Ptr GenericPredicate::evaluateSequence(const DynamicContext::Ptr &context) const
+{
+    const Item::Iterator::Ptr focus(m_operand1->evaluateSequence(context));
+    const DynamicContext::Ptr newContext(context->createFocus());
+    newContext->setFocusIterator(focus);
+
+    return makeItemMappingIterator<Item>(ConstPtr(this),
+                                         focus,
+                                         newContext);
+}
+
+Item GenericPredicate::evaluateSingleton(const DynamicContext::Ptr &context) const
+{
+    const Item::Iterator::Ptr focus(m_operand1->evaluateSequence(context));
+    const DynamicContext::Ptr newContext(context->createFocus());
+    newContext->setFocusIterator(focus);
+    return mapToItem(focus->next(), newContext);
+}
+
+SequenceType::List GenericPredicate::expectedOperandTypes() const
+{
+    SequenceType::List result;
+    result.append(CommonSequenceTypes::ZeroOrMoreItems);
+    result.append(CommonSequenceTypes::ZeroOrMoreItems);
+    return result;
+}
+
+SequenceType::Ptr GenericPredicate::staticType() const
+{
+    const SequenceType::Ptr type(m_operand1->staticType());
+    return makeGenericSequenceType(type->itemType(),
+                                   type->cardinality() | Cardinality::zeroOrOne());
+}
+
+ExpressionVisitorResult::Ptr GenericPredicate::accept(const ExpressionVisitor::Ptr &visitor) const
+{
+    return visitor->visit(this);
+}
+
+ItemType::Ptr GenericPredicate::newFocusType() const
+{
+    return m_operand1->staticType()->itemType();
+}
+
+Expression::Properties GenericPredicate::properties() const
+{
+    return CreatesFocusForLast;
+}
+
+QString GenericPredicate::description() const
+{
+    return QLatin1String("predicate");
+}
+
+Expression::ID GenericPredicate::id() const
+{
+    return IDGenericPredicate;
+}
+
+QT_END_NAMESPACE