summaryrefslogtreecommitdiff
path: root/src/xmlpatterns/expr/qaxisstep.cpp
blob: abe3b53c39e9edb1011d7e0737cefb97172fbbeb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
/****************************************************************************
**
** Copyright (C) 2010 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 "qbuiltintypes_p.h"
#include "qcommonsequencetypes_p.h"
#include "qitemmappingiterator_p.h"
#include "qgenericsequencetype_p.h"
#include "qparentnodeaxis_p.h"

#include "qaxisstep_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

namespace QPatternist
{
    /**
     * This operator is needed for the s_whenAxisNodeKindEmpty array. The @c int constructors
     * ensure we invoke another operator| such that we don't get an infinite loop.
     */
    static inline QXmlNodeModelIndex::NodeKind operator|(const QXmlNodeModelIndex::NodeKind &op1, const QXmlNodeModelIndex::NodeKind &op2)
    {
        return QXmlNodeModelIndex::NodeKind(int(op1) | int(op2));
    }
}

/**
 * @note The order is significant. It is of the same order as the values in QXmlNodeModelIndex::Axis is declared.
 */
const QXmlNodeModelIndex::NodeKind AxisStep::s_whenAxisNodeKindEmpty[] =
{
    QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,   // child;
    QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,   // descendant;
    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,// attribute;
    QXmlNodeModelIndex::NodeKind(0),                         // self;
    QXmlNodeModelIndex::NodeKind(0),                         // descendant-or-self;
    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,    // namespace;
    QXmlNodeModelIndex::Document,                                         // following;
    QXmlNodeModelIndex::Document,                                         // parent;
    QXmlNodeModelIndex::Document,                                         // ancestor
    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Namespace,         // preceding-sibling;
    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Namespace,         // following-sibling;
    QXmlNodeModelIndex::Document,                                         // preceding;
    QXmlNodeModelIndex::NodeKind(0)                          // ancestor-or-self;
};

bool AxisStep::isAlwaysEmpty(const QXmlNodeModelIndex::Axis axis, const QXmlNodeModelIndex::NodeKind nodeKind)
{
    return (s_whenAxisNodeKindEmpty[(1 >> axis) - 1] & nodeKind) != 0;
}

AxisStep::AxisStep(const QXmlNodeModelIndex::Axis a,
                   const ItemType::Ptr &nt) : m_axis(a),
                                              m_nodeTest(nt)
{
    Q_ASSERT(m_nodeTest);
    Q_ASSERT_X(BuiltinTypes::node->xdtTypeMatches(m_nodeTest), Q_FUNC_INFO,
               "We assume we're a node type.");
}

Item AxisStep::mapToItem(const QXmlNodeModelIndex &node,
                         const DynamicContext::Ptr &context) const
{
    Q_ASSERT(!node.isNull());
    Q_ASSERT(Item(node).isNode());
    Q_ASSERT(Item(node));
    Q_UNUSED(context);

    if(m_nodeTest->itemMatches(Item(node)))
        return Item(node);
    else
        return Item();
}

Item::Iterator::Ptr AxisStep::evaluateSequence(const DynamicContext::Ptr &context) const
{
    /* If we don't have a focus, it's either a bug or our parent isn't a Path
     * that have advanced the focus iterator. Hence, attempt to advance the focus on our own. */
    if(!context->contextItem())
        context->focusIterator()->next();

    Q_ASSERT(context->contextItem());

    const QXmlNodeModelIndex::Iterator::Ptr source(context->contextItem().asNode().iterate(m_axis));

    return makeItemMappingIterator<Item>(ConstPtr(this), source, context);
}

Item AxisStep::evaluateSingleton(const DynamicContext::Ptr &context) const
{
    /* If we don't have a focus, it's either a bug or our parent isn't a Path
     * that have advanced the focus iterator. Hence, attempt to advance the focus on our own. */
    if(!context->contextItem())
        context->focusIterator()->next();

    Q_ASSERT(context->contextItem());

    const QXmlNodeModelIndex::Iterator::Ptr it(context->contextItem().asNode().iterate(m_axis));
    QXmlNodeModelIndex next(it->next());

    while(!next.isNull())
    {
        const Item candidate(mapToItem(next, context));

        if(candidate)
            return candidate;
        else
            next = it->next();
    };

    return Item();
}

Expression::Ptr AxisStep::typeCheck(const StaticContext::Ptr &context,
                                    const SequenceType::Ptr &reqType)
{
    if(m_axis == QXmlNodeModelIndex::AxisParent && *m_nodeTest == *BuiltinTypes::node)
    {
        /* We only rewrite parent::node() to ParentNodeAxis. */
        return rewrite(Expression::Ptr(new ParentNodeAxis()), context)->typeCheck(context, reqType);
    }
    /* TODO temporarily disabled
    else if(isAlwaysEmpty(m_axis, static_cast<const AnyNodeType *>(m_nodeTest.data())->nodeKind()))
        return EmptySequence::create(this, context);
        */
    else
        return EmptyContainer::typeCheck(context, reqType);
}

SequenceType::Ptr AxisStep::staticType() const
{
    Cardinality cardinality;

    if(m_axis == QXmlNodeModelIndex::AxisSelf || m_axis == QXmlNodeModelIndex::AxisParent)
        cardinality = Cardinality::zeroOrOne();
    else
        cardinality = Cardinality::zeroOrMore();

    return makeGenericSequenceType(m_nodeTest,
                                   cardinality);
}

SequenceType::List AxisStep::expectedOperandTypes() const
{
    SequenceType::List result;
    result.append(CommonSequenceTypes::ZeroOrMoreNodes);
    return result;
}

Expression::Properties AxisStep::properties() const
{
    return RequiresContextItem | DisableElimination;
}

ItemType::Ptr AxisStep::expectedContextItemType() const
{
    return BuiltinTypes::node;
}

ExpressionVisitorResult::Ptr AxisStep::accept(const ExpressionVisitor::Ptr &visitor) const
{
    return visitor->visit(this);
}

QXmlNodeModelIndex::Axis AxisStep::axis() const
{
    return m_axis;
}

QString AxisStep::axisName(const QXmlNodeModelIndex::Axis axis)
{
    const char *result = 0;

    switch(axis)
    {
        /* These must not be translated. */
        case QXmlNodeModelIndex::AxisAncestorOrSelf:    result = "ancestor-or-self";    break;
        case QXmlNodeModelIndex::AxisAncestor:          result = "ancestor";            break;
        case QXmlNodeModelIndex::AxisAttributeOrTop:    result = "attribute-or-top";    break;
        case QXmlNodeModelIndex::AxisAttribute:         result = "attribute";           break;
        case QXmlNodeModelIndex::AxisChildOrTop:        result = "child-or-top";        break;
        case QXmlNodeModelIndex::AxisChild:             result = "child";               break;
        case QXmlNodeModelIndex::AxisDescendantOrSelf:  result = "descendant-or-self";  break;
        case QXmlNodeModelIndex::AxisDescendant:        result = "descendant";          break;
        case QXmlNodeModelIndex::AxisFollowing:         result = "following";           break;
        case QXmlNodeModelIndex::AxisFollowingSibling:  result = "following-sibling";   break;
        case QXmlNodeModelIndex::AxisNamespace:         result = "namespace";           break;
        case QXmlNodeModelIndex::AxisParent:            result = "parent";              break;
        case QXmlNodeModelIndex::AxisPreceding:         result = "preceding";           break;
        case QXmlNodeModelIndex::AxisPrecedingSibling:  result = "preceding-sibling";   break;
        case QXmlNodeModelIndex::AxisSelf:              result = "self";                break;
    }

    Q_ASSERT_X(result, Q_FUNC_INFO, "An unknown axis type was apparently encountered.");
    return QString::fromLatin1(result);
}

PatternPriority AxisStep::patternPriority() const
{
    return static_cast<const AnyNodeType *>(m_nodeTest.data())->patternPriority();
}

Expression::ID AxisStep::id() const
{
    return IDAxisStep;
}

QT_END_NAMESPACE