1 files changed, 142 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qnodesort.cpp b/src/xmlpatterns/expr/qnodesort.cpp
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+++ b/src/xmlpatterns/expr/qnodesort.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2011 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 "qcommonsequencetypes_p.h"
+#include "qdeduplicateiterator_p.h"
+#include "qnodesort_p.h"
+
+QT_BEGIN_NAMESPACE
+
+using namespace QPatternist;
+
+NodeSortExpression::NodeSortExpression(const Expression::Ptr &op) : SingleContainer(op)
+{
+}
+
+bool NodeSortExpression::lessThanUsingNodeModel(const Item &n1,
+                                                const Item &n2)
+{
+    Q_ASSERT(n1.isNode());
+    Q_ASSERT(n2.isNode());
+
+    if(n1.asNode().model() == n2.asNode().model())
+        return n1.asNode().compareOrder(n2.asNode()) == QXmlNodeModelIndex::Precedes;
+    else
+    {
+        /* The two nodes are from different trees. The sort order is implementation
+         * defined, but it must be stable.
+         *
+         * We do this by looking at the pointer difference. The value means nothing,
+         * but it is stable, and that's what we're looking for. */
+        return n1.asNode().model() - n2.asNode().model() < 0;
+    }
+}
+
+Item::Iterator::Ptr NodeSortExpression::evaluateSequence(const DynamicContext::Ptr &context) const
+{
+    Q_ASSERT_X(m_operand->staticType()->cardinality().allowsMany(), Q_FUNC_INFO,
+               "It makes no sense to sort a single node.");
+
+    Item::List nodes(m_operand->evaluateSequence(context)->toList());
+
+    if(nodes.isEmpty())
+        return CommonValues::emptyIterator;
+    else if(nodes.first().isAtomicValue())
+        return makeListIterator(nodes);
+    else
+    {
+        qSort(nodes.begin(), nodes.end(), lessThanUsingNodeModel);
+
+        return Item::Iterator::Ptr(new DeduplicateIterator(nodes));
+    }
+}
+
+Expression::Ptr NodeSortExpression::wrapAround(const Expression::Ptr &operand,
+                                               const StaticContext::Ptr &context)
+{
+    Q_ASSERT(operand);
+    Q_ASSERT(context);
+
+    const Expression::Ptr sort(new NodeSortExpression(operand));
+    context->wrapExpressionWith(operand.data(), sort);
+    return sort;
+}
+
+Expression::Ptr NodeSortExpression::compress(const StaticContext::Ptr &context)
+{
+    const Expression::Ptr me(SingleContainer::compress(context));
+
+    /* It make no sense to sort & deduplicate a single node. */
+    if(m_operand->staticType()->cardinality().allowsMany())
+        return me;
+    else
+        return m_operand;
+}
+
+SequenceType::Ptr NodeSortExpression::staticType() const
+{
+    return m_operand->staticType();
+}
+
+SequenceType::List NodeSortExpression::expectedOperandTypes() const
+{
+    SequenceType::List result;
+    result.append(CommonSequenceTypes::ZeroOrMoreItems);
+    return result;
+}
+
+ExpressionVisitorResult::Ptr
+NodeSortExpression::accept(const ExpressionVisitor::Ptr &visitor) const
+{
+    return visitor->visit(this);
+}
+
+Expression::Properties NodeSortExpression::properties() const
+{
+    /* The reason we disable elimination is that the assert for sorting a
+     * single node in evaluateSequence() triggers unless our compress() routine
+     * has been run. Anyhow, it's not that we would manage to write away anyway,
+     * since the node source in most(all?) cases prevents it.
+     */
+    return AffectsOrderOnly | DisableElimination;
+}
+
+QT_END_NAMESPACE