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Diffstat (limited to 'src/xmlpatterns/expr/qpath.cpp')
| -rw-r--r-- | src/xmlpatterns/expr/qpath.cpp | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qpath.cpp b/src/xmlpatterns/expr/qpath.cpp new file mode 100644 index 0000000..33bfa0f --- /dev/null +++ b/src/xmlpatterns/expr/qpath.cpp @@ -0,0 +1,271 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qbuiltintypes_p.h" +#include "qcommonsequencetypes_p.h" +#include "qgenericsequencetype_p.h" +#include "qnodesort_p.h" +#include "qpatternistlocale_p.h" +#include "qsequencemappingiterator_p.h" +#include "qtypechecker_p.h" + +#include "qpath_p.h" + +QT_BEGIN_NAMESPACE + +using namespace QPatternist; + +Path::Path(const Expression::Ptr &operand1, + const Expression::Ptr &operand2, + const Kind kind) : PairContainer(operand1, operand2) + , m_hasCreatedSorter(kind != RegularPath) + , m_isLast(false) + , m_checkXPTY0018(kind == RegularPath) + , m_kind(kind) +{ +} + +Item::Iterator::Ptr Path::mapToSequence(const Item &item, + const DynamicContext::Ptr &context) const +{ + /* item is the focus here. That is in <e/>/1, item is <e/>. However, + * we don't use it, since the context item is accessed through + * DynamicContext::focusIterator() and friends. */ + Q_ASSERT(item); + Q_UNUSED(item); /* Needed when compiling in release mode. */ + return m_operand2->evaluateSequence(context); +} + +Item::Iterator::Ptr Path::evaluateSequence(const DynamicContext::Ptr &context) const +{ + /* Note, we use the old context for m_operand1. */ + const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); + + const DynamicContext::Ptr focus(context->createFocus()); + focus->setFocusIterator(source); + + const Item::Iterator::Ptr result(makeSequenceMappingIterator<Item>(ConstPtr(this), source, focus)); + + if(m_checkXPTY0018) + { + /* This is an expensive code path, but it should happen very rarely. */ + + enum FoundItem + { + FoundNone, + FoundNode, + FoundAtomicValue + } hasFound = FoundNone; + + Item::List whenChecked; + + Item next(result->next()); + + while(next) + { + const FoundItem found = next.isAtomicValue() ? FoundAtomicValue : FoundNode; + + if(hasFound != FoundNone && hasFound != found) + { + /* It's an atomic value and we've already found a node. Mixed content. */ + context->error(QtXmlPatterns::tr("The last step in a path must contain either nodes " + "or atomic values. It cannot be a mixture between the two."), + ReportContext::XPTY0018, this); + } + else + hasFound = found; + + whenChecked.append(next); + next = result->next(); + } + + return makeListIterator(whenChecked); + } + else + return result; +} + +Item Path::evaluateSingleton(const DynamicContext::Ptr &context) const +{ + /* This function is called if both operands' cardinality is exactly-one. Therefore + * we manually go forward in the focus by calling next(). + * + * We don't check for XPTY0018, only in evaluateSequence(), since if we're guaranteed + * to evaluate to one item, we can only evaluate to one node or one atomic value. + */ + + /* Note, we use the old context for m_operand1. */ + const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); + + const DynamicContext::Ptr focus(context->createFocus()); + focus->setFocusIterator(source); + + /* This test is needed because if the focus is empty, we don't want to(nor can't) evaluate + * the next step. */ + // TODO Why are we at all invoked then? + if(source->next()) + return m_operand2->evaluateSingleton(focus); + else + return Item(); +} + +void Path::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const +{ + /* Note, we use the old context for m_operand1. */ + const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); + + const DynamicContext::Ptr focus(context->createFocus()); + focus->setFocusIterator(source); + + while(source->next()) + m_operand2->evaluateToSequenceReceiver(focus); +} + +Expression::Ptr Path::compress(const StaticContext::Ptr &context) +{ + const Expression::Ptr me(PairContainer::compress(context)); + + /* "./expr" is by now equal to "expr" since we've done + * focus/type checks, and a node sorter has been inserted. */ + if(m_operand1->is(IDContextItem)) + return m_operand2; + + /* We do this as late as we can, such that we pick up the most recent type + * from the operand. */ + if(m_isLast && !m_kind == XSLTForEach && m_operand2->staticType()->itemType() == BuiltinTypes::item) + m_checkXPTY0018 = true; + + return me; +} + +Expression::Ptr Path::typeCheck(const StaticContext::Ptr &context, + const SequenceType::Ptr &reqType) +{ + m_operand2->announceFocusType(newFocusType()); + + /* Here we apply the function conversion first, and with the error code + * that we want -- XPTY0019 instead of XPTY0004. Unfortunately + * PairContainer::typeCheck() will do the type check again, which is + * redundant in the case of when we're not XSLTForEach. + * + * If we're XSLTForEach, it means we're a synthetic "map" expression for + * implementing various XSL-T expressions, and hence don't have the + * constraint of XPTY0019. + * + * It's important that typeCheck() is run for the operands(of course), and the call to + * PairContainer::typeCheck() ensures that below, in the case that we're XSL-T code. + * + * The type we expect, CommonSequenceTypes::ZeroOrMoreNodes() needs to be in sync with + * what we return in expectedOperandTypes(). */ + if(m_kind != XSLTForEach) + { + m_operand1 = TypeChecker::applyFunctionConversion(m_operand1, + CommonSequenceTypes::ZeroOrMoreNodes, + context, + m_kind == ForApplyTemplate ? ReportContext::XTTE0520 + : ReportContext::XPTY0019); + } + + /* If our step ends with atomic values, we cannot sort. + * + * We must smack the NodeSortExpression ontop before calling typeCheck(), since the latter + * may insert an Atomizer, as possibly mandated by reqType. By doing it after, the Atomizer + * will be a parent to NodeSortExpression, as opposed to a child. + */ + if(!m_hasCreatedSorter) + { + m_hasCreatedSorter = true; + + return NodeSortExpression::wrapAround(Expression::Ptr(this), context)->typeCheck(context, reqType); + } + else + return PairContainer::typeCheck(context, reqType); +} + +SequenceType::List Path::expectedOperandTypes() const +{ + SequenceType::List result; + + /* This value needs to be in sync with what we pass to + * applyFunctionConversion() in typeCheck() above. + * + * We don't have the XPTY0019 restriction when we're synthetic XSL-T code. + */ + if(m_kind == XSLTForEach) + result.append(CommonSequenceTypes::ZeroOrMoreItems); + else + result.append(CommonSequenceTypes::ZeroOrMoreNodes); + + result.append(CommonSequenceTypes::ZeroOrMoreItems); + return result; +} + +SequenceType::Ptr Path::staticType() const +{ + const SequenceType::Ptr opType(m_operand2->staticType()); + + /* For each parent step, we evaluate the child step. So multiply the two + * cardinalities. */ + return makeGenericSequenceType(opType->itemType(), + m_operand1->staticType()->cardinality() * opType->cardinality()); +} + +ExpressionVisitorResult::Ptr Path::accept(const ExpressionVisitor::Ptr &visitor) const +{ + return visitor->visit(this); +} + +Expression::Properties Path::properties() const +{ + return CreatesFocusForLast | ((m_operand1->properties() | m_operand2->properties()) & (RequiresCurrentItem | DisableElimination)); +} + +ItemType::Ptr Path::newFocusType() const +{ + return m_operand1->staticType()->itemType(); +} + +Expression::ID Path::id() const +{ + return IDPath; +} + +QT_END_NAMESPACE |