src/xmlpatterns/expr/qvaluecomparison_p.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/expr/qvaluecomparison_p.h	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,138 @@
+/****************************************************************************
+**
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+
+#ifndef Patternist_ValueComparison_H
+#define Patternist_ValueComparison_H
+
+#include "qatomiccomparator_p.h"
+#include "qpaircontainer_p.h"
+#include "qcomparisonplatform_p.h"
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+namespace QPatternist
+{
+
+    /**
+     * @short Implements XPath 2.0 value comparions, such as the <tt>eq</tt> operator.
+     *
+     * ComparisonPlatform is inherited with @c protected scope because ComparisonPlatform
+     * must access members of ValueComparison.
+     *
+     * @see <a href="http://www.w3.org/TR/xpath20/#id-value-comparisons">XML Path Language
+     * (XPath) 2.0, 3.5.1 Value Comparisons</a>
+     * @author Frans Englich <frans.englich@nokia.com>
+     * @ingroup Patternist_expressions
+     */
+    class ValueComparison : public PairContainer,
+                            public ComparisonPlatform<ValueComparison, true>
+    {
+    public:
+        ValueComparison(const Expression::Ptr &op1,
+                        const AtomicComparator::Operator op,
+                        const Expression::Ptr &op2);
+
+        virtual Item evaluateSingleton(const DynamicContext::Ptr &) const;
+
+        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+                                          const SequenceType::Ptr &reqType);
+
+        /**
+         * @returns always CommonSequenceTypes::ExactlyOneBoolean
+         */
+        virtual SequenceType::Ptr staticType() const;
+
+        virtual SequenceType::List expectedOperandTypes() const;
+
+        /**
+         * @returns IDValueComparison
+         */
+        virtual ID id() const;
+
+        virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
+        virtual QList<QExplicitlySharedDataPointer<OptimizationPass> > optimizationPasses() const;
+
+        /**
+         * Overridden to optimize case-insensitive compares.
+         */
+        virtual Expression::Ptr compress(const StaticContext::Ptr &context);
+
+        /**
+         * @returns the operator that this ValueComparison is using.
+         */
+        inline AtomicComparator::Operator operatorID() const
+        {
+            return m_operator;
+        }
+
+        /**
+         * It is considered that the string value from @p op1 will be compared against @p op2. This
+         * function determines whether the user intends the comparison to be case insensitive. If
+         * that is the case @c true is returned, and the operands are re-written appropriately.
+         *
+         * This is a helper function for Expression classes that compares strings.
+         *
+         * @see ComparisonPlatform::useCaseInsensitiveComparator()
+         */
+        static bool isCaseInsensitiveCompare(Expression::Ptr &op1, Expression::Ptr &op2);
+
+    private:
+        const AtomicComparator::Operator m_operator;
+    };
+}
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif