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Diffstat (limited to 'src/xmlpatterns/type/qtypechecker_p.h')
| -rw-r--r-- | src/xmlpatterns/type/qtypechecker_p.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/src/xmlpatterns/type/qtypechecker_p.h b/src/xmlpatterns/type/qtypechecker_p.h new file mode 100644 index 0000000..7dd1f5f --- /dev/null +++ b/src/xmlpatterns/type/qtypechecker_p.h @@ -0,0 +1,185 @@ +/**************************************************************************** +** +** 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. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +// +// 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_TypeChecker_H +#define Patternist_TypeChecker_H + +#include "qstaticcontext_p.h" +#include "qexpression_p.h" + +QT_BEGIN_HEADER + +QT_BEGIN_NAMESPACE + +namespace QPatternist +{ + /** + * @short Contains functions that applies Function Conversion Rules and other + * kinds of compile-time type checking tasks. + * + * @ingroup Patternist_types + * @author Frans Englich <frans.englich@nokia.com> + */ + class TypeChecker + { + public: + enum Option + { + /** + * @short When set, the function conversion rules are applied. + * + * For instance, this is type promotion and conversions from @c + * xs:untypedAtomic to @c xs:date. This is done for function calls, + * but not when binding an expression to a variable. + */ + AutomaticallyConvert = 1, + + /** + * @short Whether the focus should be checked or not. + * + * Sometimes the focus is unknown at the time + * applyFunctionConversion() is called, and therefore it is + * of interest to post pone the check to later on. + */ + CheckFocus = 2, + + /** + * When applyFunctionConversion() is passed AutomaticallyConvert + * and promotion is required, such as from @c xs:integer to + * @c xs:float, there will be no conversion performed, with the + * assumption that the receiver will call Numeric::toFloat() or + * similar. + * + * However, when GeneratePromotion is set, code will be generated + * that performs this conversion regardless of what any receiver + * do. + * + * This is useful in the case where one Expression only pipes the + * result of another. The only known case of that as of this + * writing is when UserFunctionCallsite evaluates its body. + */ + GeneratePromotion + }; + typedef QFlags<Option> Options; + + /** + * @short Builds a pipeline of artificial AST nodes that ensures @p operand + * conforms to the type @p reqType by applying the Function + * Conversion Rules. + * + * This new Expression is returned, or, if no conversions were necessary, + * @p operand as it is. + * + * applyFunctionConversion() also performs various checks, such as if + * @p operand needs the focus and that the focus is defined in the + * @p context. These checks are largely guided by @p operand's + * Expression::properties(). + * + * @see <a href="http://www.w3.org/TR/xpath20/\#id-function-calls">XML Path + * Language (XPath) 2.0, 3.1.5 Function Calls</a>, more specifically the + * Function Conversion Rules + */ + static Expression::Ptr + applyFunctionConversion(const Expression::Ptr &operand, + const SequenceType::Ptr &reqType, + const StaticContext::Ptr &context, + const ReportContext::ErrorCode code = ReportContext::XPTY0004, + const Options = Options(AutomaticallyConvert | CheckFocus)); + private: + + static inline Expression::Ptr typeCheck(Expression *const op, + const StaticContext::Ptr &context, + const SequenceType::Ptr &reqType); + /** + * @short Implements the type checking and promotion part of the Function Conversion Rules. + */ + static Expression::Ptr verifyType(const Expression::Ptr &operand, + const SequenceType::Ptr &reqSeqType, + const StaticContext::Ptr &context, + const ReportContext::ErrorCode code, + const Options options); + + /** + * Determines whether type promotion is possible from one type to another. False + * is returned when a promotion is not possible or if a promotion is not needed(as when + * the types are identical), since that can be considered to not be type promotion. + * + * @returns @c true if @p fromType can be promoted to @p toType. + * @see <a href="http://www.w3.org/TR/xpath20/#promotion">XML Path Language + * (XPath) 2.0, B.1 Type Promotion</a> + */ + static bool promotionPossible(const ItemType::Ptr &fromType, + const ItemType::Ptr &toType, + const StaticContext::Ptr &context); + + /** + * @short Centralizes a message-string to reduce work for translators + * and increase consistency. + */ + static inline QString wrongType(const NamePool::Ptr &np, + const ItemType::Ptr &reqType, + const ItemType::Ptr &opType); + + /** + * No implementation is provided for this constructor. This class + * is not supposed to be instantiated. + */ + inline TypeChecker(); + + Q_DISABLE_COPY(TypeChecker) + }; +} + +QT_END_NAMESPACE + +QT_END_HEADER + +#endif |