summaryrefslogtreecommitdiff
path: root/src/xmlpatterns/expr/qexpressionfactory.cpp
blob: 6b11678080a13bf09d8637fbbc520251a29d9978 (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
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** 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, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, 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.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QBuffer>
#include <QByteArray>

#include "qcalltemplate_p.h"
#include "qcommonsequencetypes_p.h"
#include "qdebug_p.h"
#include "qexpression_p.h"
#include "qgenericstaticcontext_p.h"
#include "qoperandsiterator_p.h"
#include "qoptimizationpasses_p.h"
#include "qparsercontext_p.h"
#include "qpath_p.h"
#include "qquerytransformparser_p.h"
#include "qstaticfocuscontext_p.h"
#include "qtokenrevealer_p.h"
#include "qxquerytokenizer_p.h"
#include "qxslttokenizer_p.h"

#include "qexpressionfactory_p.h"

QT_BEGIN_NAMESPACE

namespace QPatternist {

/**
 * @short The entry point to the parser.
 *
 * @param info supplies the information the parser & scanner
 * needs to create expressions. The created expression, if everything
 * succeeds, can be retrieved via the object @p info points to.
 * @returns non-negative if the parser fails.
 * @see ExpressionFactory::createExpression()
 */
extern int XPathparse(QPatternist::ParserContext *const info);

Expression::Ptr ExpressionFactory::createExpression(const QString &expr,
                                                    const StaticContext::Ptr &context,
                                                    const QXmlQuery::QueryLanguage lang,
                                                    const SequenceType::Ptr &requiredType,
                                                    const QUrl &queryURI,
                                                    const QXmlName &initialTemplateName)
{
    if(lang == QXmlQuery::XSLT20)
    {
        QByteArray query(expr.toUtf8());
        QBuffer buffer(&query);
        buffer.open(QIODevice::ReadOnly);

        return createExpression(&buffer,
                                context,
                                lang,
                                requiredType,
                                queryURI,
                                initialTemplateName);
    }
    else
    {
        return createExpression(Tokenizer::Ptr(new XQueryTokenizer(expr, queryURI)),
                                context,
                                lang,
                                requiredType,
                                queryURI,
                                initialTemplateName);
    }
}

Expression::Ptr ExpressionFactory::createExpression(QIODevice *const device,
                                                    const StaticContext::Ptr &context,
                                                    const QXmlQuery::QueryLanguage lang,
                                                    const SequenceType::Ptr &requiredType,
                                                    const QUrl &queryURI,
                                                    const QXmlName &initialTemplateName)
{
    Q_ASSERT(device);
    Q_ASSERT(device->isReadable());

    Tokenizer::Ptr tokenizer;

    if(lang == QXmlQuery::XSLT20)
        tokenizer = Tokenizer::Ptr(new XSLTTokenizer(device, queryURI, context, context->namePool()));
    else
        tokenizer = Tokenizer::Ptr(new XQueryTokenizer(QString::fromUtf8(device->readAll()), queryURI));

    return createExpression(tokenizer, context, lang, requiredType, queryURI, initialTemplateName);
}

Expression::Ptr ExpressionFactory::createExpression(const Tokenizer::Ptr &tokenizer,
                                                    const StaticContext::Ptr &context,
                                                    const QXmlQuery::QueryLanguage lang,
                                                    const SequenceType::Ptr &requiredType,
                                                    const QUrl &queryURI,
                                                    const QXmlName &initialTemplateName)
{
    Q_ASSERT(context);
    Q_ASSERT(requiredType);
    Q_ASSERT(queryURI.isValid());

    Tokenizer::Ptr effectiveTokenizer(tokenizer);
#ifdef Patternist_DEBUG
    effectiveTokenizer = Tokenizer::Ptr(new TokenRevealer(queryURI, tokenizer));
#endif

    OptimizationPasses::Coordinator::init();

    const ParserContext::Ptr info(new ParserContext(context, lang, effectiveTokenizer.data()));
    info->initialTemplateName = initialTemplateName;

    effectiveTokenizer->setParserContext(info);

    const int bisonRetval = XPathparse(info.data());

    Q_ASSERT_X(bisonRetval == 0, Q_FUNC_INFO,
               "We shouldn't be able to get an error, because we throw exceptions.");
    Q_UNUSED(bisonRetval); /* Needed when not compiled in debug mode, since bisonRetval won't
                            * be used in the Q_ASSERT_X above. */

    Expression::Ptr result(info->queryBody);

    if(!result)
    {
        context->error(QtXmlPatterns::tr("A library module cannot be evaluated "
                                         "directly. It must be imported from a "
                                         "main module."),
                       ReportContext::XPST0003,
                       QSourceLocation(queryURI, 1, 1));
    }

    /* Optimization: I think many things are done in the wrong order below. We
     * probably want everything typechecked before compressing, since we can
     * have references all over the place(variable references, template
     * invocations, function callsites). This could even be a source to bugs.
     */

    /* Here, we type check user declared functions and global variables. This
     * means that variables and functions that are not used are type
     * checked(which they otherwise wouldn't have been), and those which are
     * used, are type-checked twice, unfortunately. */

    const bool hasExternalFocus = context->contextItemType();

    if(lang == QXmlQuery::XSLT20)
    {
        /* Bind xsl:call-template instructions to their template bodies.
         *
         * We do this before type checking and compressing them, because a
         * CallTemplate obviously needs its template before being compressed.
         *
         * Also, we do this before type checking and compressing user
         * functions, since they can contain template call sites.
         */
        for(int i = 0; i < info->templateCalls.count(); ++i)
        {
            CallTemplate *const site = info->templateCalls.at(i)->as<CallTemplate>();
            const QXmlName targetName(site->name());
            const Template::Ptr t(info->namedTemplates.value(targetName));

            if(t)
                site->setTemplate(t);
            else
            {
                context->error(QtXmlPatterns::tr("No template by name %1 exists.").arg(formatKeyword(context->namePool(), targetName)),
                               ReportContext::XTSE0650,
                               site);
            }
        }
    }

    /* Type check and compress user functions. */
    {
        const UserFunction::List::const_iterator end(info->userFunctions.constEnd());
        UserFunction::List::const_iterator it(info->userFunctions.constBegin());

        /* If the query has a focus(which is common, in the case of a
         * stylesheet), we must ensure that the focus isn't visible in the
         * function body. */
        StaticContext::Ptr effectiveContext;

        if(hasExternalFocus)
        {
            effectiveContext = StaticContext::Ptr(new StaticFocusContext(ItemType::Ptr(),
                                                                         context));
        }
        else
            effectiveContext = context;

        for(; it != end; ++it)
        {
            pDebug() << "-----      User Function Typecheck      -----";
            registerLastPath((*it)->body());

            /* We will most likely call body()->typeCheck() again, once for
             * each callsite. That is, it will be called from
             * UserFunctionCallsite::typeCheck(), which will be called
             * indirectly when we check the query body. */
            const Expression::Ptr typeCheck((*it)->body()->typeCheck(effectiveContext,
                                                                     (*it)->signature()->returnType()));
            /* We don't have to call (*it)->setBody(typeCheck) here since it's
             * only used directly below. */
            processTreePass(typeCheck, UserFunctionTypeCheck);
            pDebug() << "------------------------------";

            pDebug() << "-----      User Function Compress      -----";
            const Expression::Ptr comp(typeCheck->compress(effectiveContext));
            (*it)->setBody(comp);
            processTreePass(comp, UserFunctionCompression);
            pDebug() << "------------------------------";
        }
    }

    /* Type check and compress global variables. */
    {
        const VariableDeclaration::Stack::const_iterator vend(info->variables.constEnd());
        VariableDeclaration::Stack::const_iterator vit(info->variables.constBegin());
        for(; vit != vend; ++vit)
        {
            Q_ASSERT(*vit);
            /* This is a bit murky, the global variable will have it
             * Expression::typeCheck() function called from all its references,
             * but we also want to check it here globally, so we do
             * typechecking using a proper focus. */
            if((*vit)->type == VariableDeclaration::ExternalVariable)
                continue;

            pDebug() << "-----      Global Variable Typecheck      -----";
            Q_ASSERT((*vit)->expression());
            /* We supply ZeroOrMoreItems, meaning the variable can evaluate to anything. */
            // FIXME which is a source to bugs
            // TODO What about compressing variables?
            const Expression::Ptr
            nev((*vit)->expression()->typeCheck(context, CommonSequenceTypes::ZeroOrMoreItems));
            processTreePass(nev, GlobalVariableTypeCheck);
            pDebug() << "------------------------------";
        }
    }

    /* Do all tests specific to XSL-T. */
    if(lang == QXmlQuery::XSLT20)
    {
        /* Type check and compress named templates. */
        {
            pDebug() << "Have " << info->namedTemplates.count() << "named templates";

            QMutableHashIterator<QXmlName, Template::Ptr> it(info->namedTemplates);

            while(it.hasNext())
            {
                it.next();
                processNamedTemplate(it.key(), it.value()->body, TemplateInitial);

                it.value()->body = it.value()->body->typeCheck(context, CommonSequenceTypes::ZeroOrMoreItems);
                processNamedTemplate(it.key(), it.value()->body, TemplateTypeCheck);

                it.value()->body = it.value()->body->compress(context);
                processNamedTemplate(it.key(), it.value()->body, TemplateCompress);

                it.value()->compileParameters(context);
            }
        }

        /* Type check and compress template rules. */
        {
            QHashIterator<QXmlName, TemplateMode::Ptr> it(info->templateRules);

            /* Since a pattern can exist of AxisStep, its typeCheck() stage
             * requires a focus. In the case that we're invoked with a name but
             * no focus, this will yield a compile error, unless we declare a
             * focus manually. This only needs to be done for the pattern
             * expression, since the static type of the pattern is used as the
             * static type for the focus of the template body. */
            StaticContext::Ptr patternContext;
            if(hasExternalFocus)
                patternContext = context;
            else
                patternContext = StaticContext::Ptr(new StaticFocusContext(BuiltinTypes::node, context));

            /* For each template pattern. */
            while(it.hasNext())
            {
                it.next();
                const TemplateMode::Ptr &mode = it.value();
                const int len = mode->templatePatterns.count();
                TemplatePattern::ID currentTemplateID = -1;
                bool hasDoneItOnce = false;

                /* For each template pattern. */
                for(int i = 0; i < len; ++i)
                {
                    /* We can't use references for these two members, since we
                     * assign to them. */
                    const TemplatePattern::Ptr &pattern = mode->templatePatterns.at(i);
                    Expression::Ptr matchPattern(pattern->matchPattern());

                    processTemplateRule(pattern->templateTarget()->body,
                                        pattern, mode->name(), TemplateInitial);

                    matchPattern = matchPattern->typeCheck(patternContext, CommonSequenceTypes::ZeroOrMoreItems);
                    matchPattern = matchPattern->compress(patternContext);
                    pattern->setMatchPattern(matchPattern);

                    if(currentTemplateID == -1 && hasDoneItOnce)
                    {
                        currentTemplateID = pattern->id();
                        continue;
                    }
                    else if(currentTemplateID == pattern->id() && hasDoneItOnce)
                    {
                        hasDoneItOnce = false;
                        continue;
                    }

                    hasDoneItOnce = true;
                    currentTemplateID = pattern->id();
                    Expression::Ptr body(pattern->templateTarget()->body);

                    /* Patterns for a new template has started, we must
                     * deal with the body & parameters. */
                    {
                        /* TODO type is wrong, it has to be the union of all
                         * patterns. */
                        const StaticContext::Ptr focusContext(new StaticFocusContext(matchPattern->staticType()->itemType(),
                                                                                     context));
                        body = body->typeCheck(focusContext, CommonSequenceTypes::ZeroOrMoreItems);

                        pattern->templateTarget()->compileParameters(focusContext);
                    }

                    processTemplateRule(body, pattern, mode->name(), TemplateTypeCheck);

                    body = body->compress(context);

                    pattern->templateTarget()->body = body;
                    processTemplateRule(body, pattern, mode->name(), TemplateCompress);
                }

                mode->finalize();
            }
        }

        /* Add templates in mode #all to all other modes.
         *
         * We do this after the templates has been typechecked and compressed,
         * since otherwise it will be done N times for the built-in templates,
         * where N is the count of different templates, instead of once. */
        {
            const QXmlName nameModeAll(QXmlName(StandardNamespaces::InternalXSLT,
                                                StandardLocalNames::all));
            const TemplateMode::Ptr &modeAll = info->templateRules[nameModeAll];

            Q_ASSERT_X(modeAll, Q_FUNC_INFO,
                       "We should at least have the builtin templates.");
            QHashIterator<QXmlName, TemplateMode::Ptr> it(info->templateRules);

            while(it.hasNext())
            {
                it.next();

                /* Don't add mode #all to mode #all. */
                if(it.key()  == nameModeAll)
                    continue;

                it.value()->addMode(modeAll);
            }
        }
    }

    /* Type check and compress the query body. */
    {
        pDebug() << "----- Initial AST build. -----";
        processTreePass(result, QueryBodyInitial);
        pDebug() << "------------------------------";

        pDebug() << "-----     Type Check     -----";
        registerLastPath(result);
        result->rewrite(result, result->typeCheck(context, requiredType), context);
        processTreePass(result, QueryBodyTypeCheck);
        pDebug() << "------------------------------";

        pDebug() << "-----      Compress      -----";
        result->rewrite(result, result->compress(context), context);
        processTreePass(result, QueryBodyCompression);
        pDebug() << "------------------------------";
    }

    return result;
}

void ExpressionFactory::registerLastPath(const Expression::Ptr &operand)
{
    OperandsIterator it(operand, OperandsIterator::IncludeParent);
    Expression::Ptr next(it.next());

    while(next)
    {
        if(next->is(Expression::IDPath))
        {
            next->as<Path>()->setLast();
            next = it.skipOperands();
        }
        else
            next = it.next();
    }
}

void ExpressionFactory::processTreePass(const Expression::Ptr &,
                                        const CompilationStage)
{
}

void ExpressionFactory::processTemplateRule(const Expression::Ptr &body,
                                            const TemplatePattern::Ptr &pattern,
                                            const QXmlName &mode,
                                            const TemplateCompilationStage stage)
{
    Q_UNUSED(body);
    Q_UNUSED(pattern);
    Q_UNUSED(mode);
    Q_UNUSED(stage);
}

void ExpressionFactory::processNamedTemplate(const QXmlName &name,
                                             const Expression::Ptr &tree,
                                             const TemplateCompilationStage stage)
{
    Q_UNUSED(name);
    Q_UNUSED(tree);
    Q_UNUSED(stage);
}

} // namespace QPatternist

QT_END_NAMESPACE