summaryrefslogtreecommitdiffstats
path: root/src/xmlpatterns/acceltree/qacceltree_p.h
blob: a2962139aa5eed8c426a34a94ce0444f4f609f15 (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
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** 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 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 http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/

//
//  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_AccelTree_H
#define Patternist_AccelTree_H

#include <QHash>
#include <QUrl>
#include <QVector>
#include <QXmlName>

#include "qitem_p.h"
#include "qnamepool_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist
{
    template<bool> class AccelTreeBuilder;

    /**
     * @short Stores an XML document using the XPath Accelerator scheme, also
     * known as pre/post numbering.
     *
     * Working on this code will be destructive without a proper understanding of
     * the Accelerator scheme, so do check out the links. We don't implement any form
     * of staircase join, although that is only due to time constraints.
     *
     * @author Frans Englich <frans.englich@nokia.com>
     * @see <a href="http://www.pathfinder-xquery.org/?q=research/xpath-accel">XPath
     * Accelerator</a>
     * @see <a href="http://www.pathfinder-xquery.org/files/xpath-accel.pdf">Accelerating
     * XPath Location Steps, Torsten Grust</a>
     * @see <a href="http://citeseer.ist.psu.edu/cache/papers/cs/29367/http:zSzzSzwww.informatik.uni-konstanz.dezSz~grustzSzfileszSzstaircase-join.pdf/grust03staircase.pdf">Staircase Join:
     * Teach a Relational DBMS to Watch its (Axis) Steps</a>
     * @see <a href="http://ftp.cwi.nl/CWIreports/INS/INS-E0510.pdf">Loop-lifted
     * staircase join: from XPath to XQuery, Torsten Grust</a>
     * @see <a href="http://englich.wordpress.com/2007/01/09/xmlstat/">xmlstat, Frans Englich</a>
     * @see <a href"http://www.inf.uni-konstanz.de/dbis/publications/download/accelerating-locsteps.pdf">Accelerating
     * XPath Evaluation in Any RDBMS, Torsten Grust</a>
     */
    class AccelTree : public QAbstractXmlNodeModel
    {
        friend class AccelTreePrivate;
    public:
        using QAbstractXmlNodeModel::createIndex;

        typedef QExplicitlySharedDataPointer<AccelTree> Ptr;
        typedef qint32 PreNumber;
        typedef PreNumber PostNumber;
        typedef qint8 Depth;

        AccelTree(const QUrl &docURI, const QUrl &bURI);

        /**
         * @short Houses data for a node, and that all node kinds have.
         *
         * BasicNodeData is internal to the Accel tree implementation, and is
         * only used by those classes.
         *
         * @author Frans Englich <frans.englich@nokia.com>
         * @todo Can't m_kind be coded somewhere else? If m_name is invalid,
         * its bits can be used to distinguish the node types that doesn't have
         * names, and for elements, attributes and processing instructions, we need
         * two bits, somewhere. Attributes and processing instructions can't have a
         * size, is that of help? There's also certain rules for the names. For instance,
         * a processing instruction will never have a prefix nor namespace. Neither
         * will an attribute node have a default, non-empty namespace, right?
         * @todo Compress text nodes, add general support for it in Patternist.
         */
        class BasicNodeData
        {
        public:
            /* No need to initialize the members. See AccelTreeBuilder. */
            inline BasicNodeData()
            {
            }

            inline BasicNodeData(const PreNumber aDepth,
                                 const PreNumber aParent,
                                 const QXmlNodeModelIndex::NodeKind k,
                                 const PreNumber s,
                                 const QXmlName n = QXmlName()) : m_parent(aParent)
                                                                , m_size(s)
                                                                , m_name(n)
                                                                , m_depth(aDepth)
                                                                , m_kind(k)
            {
            }

            inline Depth depth() const
            {
                return m_depth;
            }

            inline PreNumber parent() const
            {
                return m_parent;
            }

            /**
             * @see AccelTree::size()
             */
            inline PreNumber size() const
            {
                /* Remember that we use the m_size to signal compression if
                 * we're a text node. */
                if(m_kind == QXmlNodeModelIndex::Text)
                    return 0;
                else
                    return m_size;
            }

            inline void setSize(const PreNumber aSize)
            {
                m_size = aSize;
            }

            inline QXmlNodeModelIndex::NodeKind kind() const
            {
                return m_kind;
            }

            inline QXmlName name() const
            {
                return m_name;
            }

            inline bool isCompressed() const
            {
                Q_ASSERT_X(m_kind == QXmlNodeModelIndex::Text, Q_FUNC_INFO,
                           "Currently, only text nodes are compressed.");
                /* Note, we don't call size() here, since it has logic for text
                 * nodes. */
                return m_size == IsCompressed;
            }

        private:
            /**
             * This is the pre number of the parent.
             */
            PreNumber                       m_parent;

            /**
             * This is the count of children this node has.
             *
             * In the case of a text node, which cannot have children,
             * it is set to IsCompressed, if the content has been the result
             * of CompressedWhitespace::compress(). If it's not compressed,
             * it is zero.
             */
            PreNumber                       m_size;

            /**
             * For text nodes, and less importantly, comments,
             * this variable is not used.
             */
            QXmlName                        m_name;

            Depth                           m_depth;

            /**
             * Technically it is sufficient with 7 bits. However, at least MSVC
             * 2005 miscompiles it such that QXmlNodeModelIndex::Text becomes
             * -64 instead of 64 with hilarious crashes as result.
             *
             * Fortunately this extra bit would be padded anyway.
             */
            QXmlNodeModelIndex::NodeKind    m_kind : 8;
        };

        virtual QUrl baseUri(const QXmlNodeModelIndex &ni) const;
        virtual QUrl documentUri(const QXmlNodeModelIndex &ni) const;
        virtual QXmlNodeModelIndex::NodeKind kind(const QXmlNodeModelIndex &ni) const;
        virtual QXmlNodeModelIndex::DocumentOrder compareOrder(const QXmlNodeModelIndex &ni1,
                                                               const QXmlNodeModelIndex &ni2) const;

        /**
         * @short Returns the root node.
         *
         * This function does not use @p n, so a default constructed
         * QXmlNodeModelIndex may be passed.
         */
        virtual QXmlNodeModelIndex root(const QXmlNodeModelIndex &n) const;

        virtual QXmlNodeModelIndex parent(const QXmlNodeModelIndex &ni) const;
        virtual QXmlNodeModelIndex::Iterator::Ptr iterate(const QXmlNodeModelIndex &ni,
                                                          QXmlNodeModelIndex::Axis axis) const;
        virtual QXmlName name(const QXmlNodeModelIndex &ni) const;
        virtual QVector<QXmlName> namespaceBindings(const QXmlNodeModelIndex &n) const;
        virtual void sendNamespaces(const QXmlNodeModelIndex &n,
                                    QAbstractXmlReceiver *const receiver) const;
        virtual QString stringValue(const QXmlNodeModelIndex &n) const;
        virtual QVariant typedValue(const QXmlNodeModelIndex &n) const;
        virtual Item::Iterator::Ptr sequencedTypedValue(const QXmlNodeModelIndex &n) const;
        virtual ItemType::Ptr type(const QXmlNodeModelIndex &ni) const;
        virtual QXmlNodeModelIndex elementById(const QXmlName &id) const;
        virtual QVector<QXmlNodeModelIndex> nodesByIdref(const QXmlName &idref) const;
        virtual void copyNodeTo(const QXmlNodeModelIndex &node,
                                QAbstractXmlReceiver *const receiver,
                                const NodeCopySettings &settings) const;

        friend class AccelTreeBuilder<false>;
        friend class AccelTreeBuilder<true>;

        enum Constants
        {
            IsCompressed = 1
        };

        /**
         * The key is the pre number of an element, and the value is a vector
         * containing the namespace declarations being declared on that
         * element. Therefore, it does not reflect the namespaces being in
         * scope for that element. For that, a walk along axis ancestor is
         * necessary.
         */
        QHash<PreNumber, QVector<QXmlName> > namespaces;

        /**
         * Stores data for nodes. The QHash's value is the data of the processing instruction, and the
         * content of a text node or comment.
         */
        QHash<PreNumber, QString> data;

        QVector<BasicNodeData> basicData;
        QHash<PreNumber, QPair<qint64, qint64> > sourcePositions;

        inline QUrl documentUri() const
        {
            return m_documentURI;
        }

        inline QUrl baseUri() const
        {
            return m_baseURI;
        }

        /**
         * @short Returns @c true if the node identified by @p pre has child
         * nodes(in the sense of the XDM), but also if it has namespace nodes,
         * or attribute nodes.
         */
        inline bool hasChildren(const PreNumber pre) const
        {
            return basicData.at(pre).size() > 0;
        }

        /**
         * @short Returns the parent node of @p pre.
         *
         * If @p pre parent doesn't have a parent node, the return value is
         * undefined.
         *
         * @see hasParent()
         */
        inline PreNumber parent(const PreNumber pre) const
        {
            return basicData.at(pre).parent();
        }

        inline bool hasParent(const PreNumber pre) const
        {
            return basicData.at(pre).depth() > 0;
        }

        inline bool hasFollowingSibling(const PreNumber pre) const
        {
            return pre < maximumPreNumber();
        }

        inline PostNumber postNumber(const PreNumber pre) const
        {
            const BasicNodeData &b = basicData.at(pre);
            return pre + b.size() - b.depth();
        }

        inline QXmlNodeModelIndex::NodeKind kind(const PreNumber pre) const
        {
            return basicData.at(pre).kind();
        }

        inline PreNumber maximumPreNumber() const
        {
            return basicData.count() - 1;
        }

        inline PreNumber toPreNumber(const QXmlNodeModelIndex n) const
        {
            return n.data();
        }

        inline PreNumber size(const PreNumber pre) const
        {
            Q_ASSERT_X(basicData.at(pre).size() != -1, Q_FUNC_INFO,
                       "The size cannot be -1. That means an uninitialized value is attempted to be used.");
            return basicData.at(pre).size();
        }

        inline Depth depth(const PreNumber pre) const
        {
            return basicData.at(pre).depth();
        }

        void printStats(const NamePool::Ptr &np) const;

        inline QXmlName name(const PreNumber pre) const
        {
            return basicData.at(pre).name();
        }

        inline bool isCompressed(const PreNumber pre) const
        {
            return basicData.at(pre).isCompressed();
        }

        static inline bool hasPrefix(const QVector<QXmlName> &nbs, const QXmlName::PrefixCode prefix);

        QUrl m_documentURI;
        QUrl m_baseURI;

    protected:
        virtual QXmlNodeModelIndex nextFromSimpleAxis(QAbstractXmlNodeModel::SimpleAxis,
                                                      const QXmlNodeModelIndex&) const;
        virtual QVector<QXmlNodeModelIndex> attributes(const QXmlNodeModelIndex &element) const;

    private:
        /**
         * Returns the source location for the object with the given @p index.
         */
        QSourceLocation sourceLocation(const QXmlNodeModelIndex &index) const;

        /**
         * Copies the children of @p node to @p receiver.
         */
        inline void copyChildren(const QXmlNodeModelIndex &node,
                                 QAbstractXmlReceiver *const receiver,
                                 const NodeCopySettings &settings) const;

        /**
         * The key is the xml:id value, and the value is the element
         * with that value.
         */
        QHash<QXmlName::LocalNameCode, PreNumber> m_IDs;
    };
}

Q_DECLARE_TYPEINFO(QPatternist::AccelTree::BasicNodeData, Q_MOVABLE_TYPE);

QT_END_NAMESPACE

QT_END_HEADER

#endif