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** This file is part of the QtXmlPatterns module of the Qt Toolkit.

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****************************************************************************/

#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