--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/expr/qorderby.cpp Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,261 @@
+/****************************************************************************
+**
+** 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 <QtAlgorithms>
+
+#include "qcommonsequencetypes_p.h"
+#include "qnodebuilder_p.h"
+#include "qschemanumeric_p.h"
+#include "qpatternistlocale_p.h"
+#include "qreturnorderby_p.h"
+#include "qsorttuple_p.h"
+#include "qsequencemappingiterator_p.h"
+
+#include "qorderby_p.h"
+
+QT_BEGIN_NAMESPACE
+
+using namespace QPatternist;
+
+OrderBy::OrderBy(const Stability stability,
+ const OrderSpec::Vector &aOrderSpecs,
+ const Expression::Ptr &op,
+ ReturnOrderBy *const returnOrderBy) : SingleContainer(op)
+ , m_stability(stability)
+ , m_orderSpecs(aOrderSpecs)
+ , m_returnOrderBy(returnOrderBy)
+{
+ Q_ASSERT(m_returnOrderBy);
+}
+
+void OrderBy::OrderSpec::prepare(const Expression::Ptr &source,
+ const StaticContext::Ptr &context)
+{
+ m_expr = source;
+ const ItemType::Ptr t(source->staticType()->itemType());
+ prepareComparison(fetchComparator(t, t, context));
+}
+
+/**
+ * @short Functor used by Qt's qSort() and qStableSort(). Used for FLWOR's
+ * <tt>order by</tt> expression.
+ *
+ * This must be in the global namespace, since it is specializing qLess(), which
+ * is in the global namespace. Hence it can't be in QPatternist.
+ */
+template<>
+class qLess<Item::List>
+{
+private:
+
+ static inline bool isNaN(const Item &i)
+ {
+ return BuiltinTypes::xsDouble->xdtTypeMatches(i.type()) &&
+ i.as<Numeric>()->isNaN();
+ }
+
+public:
+ inline qLess(const OrderBy::OrderSpec::Vector &orderspecs,
+ const DynamicContext::Ptr &context) : m_orderSpecs(orderspecs)
+ , m_context(context)
+ {
+ Q_ASSERT(!m_orderSpecs.isEmpty());
+ Q_ASSERT(context);
+ }
+
+ inline bool operator()(const Item &item1, const Item &item2) const
+ {
+ const SortTuple *const s1 = item1.as<SortTuple>();
+ const SortTuple *const s2 = item2.as<SortTuple>();
+
+ const Item::Vector &sortKeys1 = s1->sortKeys();
+ const Item::Vector &sortKeys2 = s2->sortKeys();
+ const int len = sortKeys1.count();
+ Q_ASSERT(sortKeys1.count() == sortKeys2.count());
+
+ for(int i = 0; i < len; ++i)
+ {
+ const Item &i1 = sortKeys1.at(i);
+ const Item &i2 = sortKeys2.at(i);
+ const OrderBy::OrderSpec &orderSpec = m_orderSpecs.at(i);
+
+ if(!i1)
+ {
+ if(i2 && !isNaN(i2))
+ {
+ /* We got ((), item()). */
+ return orderSpec.orderingEmptySequence == StaticContext::Least ? orderSpec.direction == OrderBy::OrderSpec::Ascending
+ : orderSpec.direction != OrderBy::OrderSpec::Ascending;
+ }
+ else
+ return false;
+ }
+
+ if(!i2)
+ {
+ if(i1 && !isNaN(i1))
+ /* We got (item(), ()). */
+ return orderSpec.orderingEmptySequence == StaticContext::Greatest ? orderSpec.direction == OrderBy::OrderSpec::Ascending
+ : orderSpec.direction != OrderBy::OrderSpec::Ascending;
+ else
+ return false;
+ }
+
+ Q_ASSERT(orderSpec.direction == OrderBy::OrderSpec::Ascending ||
+ orderSpec.direction == OrderBy::OrderSpec::Descending);
+ const AtomicComparator::ComparisonResult result = orderSpec.detailedFlexibleCompare(i1, i2, m_context);
+
+ switch(result)
+ {
+ case AtomicComparator::LessThan:
+ return orderSpec.direction == OrderBy::OrderSpec::Ascending;
+ case AtomicComparator::GreaterThan:
+ return orderSpec.direction != OrderBy::OrderSpec::Ascending;
+ case AtomicComparator::Equal:
+ continue;
+ case AtomicComparator::Incomparable:
+ Q_ASSERT_X(false, Q_FUNC_INFO, "This code path assume values are always comparable.");
+ }
+ }
+
+ return false;
+ }
+
+private:
+ /* Yes, we store references here. */
+ const OrderBy::OrderSpec::Vector & m_orderSpecs;
+ const DynamicContext::Ptr & m_context;
+};
+
+Item::Iterator::Ptr OrderBy::mapToSequence(const Item &i,
+ const DynamicContext::Ptr &) const
+{
+ return i.as<SortTuple>()->value();
+}
+
+Item::Iterator::Ptr OrderBy::evaluateSequence(const DynamicContext::Ptr &context) const
+{
+ Item::List tuples(m_operand->evaluateSequence(context)->toList());
+
+ const qLess<Item::List> sorter(m_orderSpecs, context);
+
+ Q_ASSERT(m_stability == StableOrder || m_stability == UnstableOrder);
+
+ /* On one hand we could just disregard stability and always use qStableSort(), but maybe qSort()
+ * is a bit faster? */
+ if(m_stability == StableOrder)
+ qStableSort(tuples.begin(), tuples.end(), sorter);
+ else
+ {
+ Q_ASSERT(m_stability == UnstableOrder);
+ qSort(tuples.begin(), tuples.end(), sorter);
+ }
+
+ return makeSequenceMappingIterator<Item>(ConstPtr(this),
+ makeListIterator(tuples),
+ context);
+}
+
+Expression::Ptr OrderBy::typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType)
+{
+ m_returnOrderBy->setStay(true);
+
+ /* It's important we do the typeCheck() before calling OrderSpec::prepare(), since
+ * atomizers must first be inserted. */
+ const Expression::Ptr me(SingleContainer::typeCheck(context, reqType));
+
+ const Expression::List ops(m_returnOrderBy->operands());
+ const int len = ops.count();
+ Q_ASSERT(ops.count() > 1);
+ Q_ASSERT(m_orderSpecs.count() == ops.count() - 1);
+
+ for(int i = 1; i < len; ++i)
+ m_orderSpecs[i - 1].prepare(ops.at(i), context);
+
+ return me;
+
+ /* It's not meaningful to sort a single item or less, so rewrite ourselves
+ * away if that is the case. This is an optimization. */
+ /* TODO: How do we remove ReturnOrderBy?
+ if(Cardinality::zeroOrOne().isMatch(m_operand->staticType()->cardinality()))
+ return m_operand->typeCheck(context, reqType);
+ else
+ return SingleContainer::typeCheck(context, reqType);
+ */
+}
+
+Expression::Properties OrderBy::properties() const
+{
+ return m_operand->properties() & DisableElimination;
+}
+
+Expression::Ptr OrderBy::compress(const StaticContext::Ptr &context)
+{
+ /* If we only will produce one item, there's no point in sorting. */
+ if(m_operand->staticType()->cardinality().allowsMany())
+ return SingleContainer::compress(context);
+ else
+ {
+ m_returnOrderBy->setStay(false);
+ return m_operand->compress(context);
+ }
+}
+
+SequenceType::Ptr OrderBy::staticType() const
+{
+ return m_operand->staticType();
+}
+
+SequenceType::List OrderBy::expectedOperandTypes() const
+{
+ SequenceType::List result;
+ result.append(CommonSequenceTypes::ZeroOrMoreItems);
+ return result;
+}
+
+ExpressionVisitorResult::Ptr
+OrderBy::accept(const ExpressionVisitor::Ptr &visitor) const
+{
+ return visitor->visit(this);
+}
+
+QT_END_NAMESPACE