source: trunk/src/xmlpatterns/expr/qtemplate.cpp@ 168

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#include "qdynamiccontextstore_p.h"
#include "qpatternistlocale_p.h"

#include "qtemplate_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

const SourceLocationReflection* Template::actualReflection() const
{
    return this;
}

DynamicContext::TemplateParameterHash Template::parametersAsHash() const
{
    DynamicContext::TemplateParameterHash retval;
    const int len = templateParameters.count();

    for(int i = 0; i < len; ++i)
    {
        const VariableDeclaration::Ptr &at = templateParameters.at(i);
        retval.insert(at->name, at->expression());
    }

    return retval;
}

void Template::raiseXTSE0680(const ReportContext::Ptr &context,
                             const QXmlName &name,
                             const SourceLocationReflection *const reflection)
{
    context->error(QtXmlPatterns::tr("The parameter %1 is passed, but no corresponding %2 exists.")
                                     .arg(formatKeyword(context->namePool(), name),
                                          formatKeyword(QLatin1String("xsl:param"))),
                   ReportContext::XTSE0680,
                   reflection);
}

DynamicContext::Ptr Template::createContext(const TemplateInvoker *const invoker,
                                            const DynamicContext::Ptr &context,
                                            const bool isCallTemplate) const
{
    Q_ASSERT(invoker);
    Q_ASSERT(context);

    /* We have:
     * - xsl:params in the target template (if any) which may provide
     *   default values.
     * - xsl:with-params in the caller (if any) which provides values.
     *
     * We need to, for each parameter:
     * - If the called template provides no default value and the caller
     *   has no value, it's an error
     * - If the called template has a default value and the caller provides
     *   none, it should be used
     * - In any case the caller provides a value, it needs to be used.
     *
     * Problems to look out for:
     *
     * - Each xsl:param is in scope for the subsequent xsl:params. Hence,
     *   the evaluation of one xsl:param can depend on another xsl:param,
     *   and so on
     * - The focus for xsl:params is different from the focus for
     *   the xsl:with-params
     * - The xsl:with-params are not in scope for the xsl:params.
     */

    WithParam::Hash withParams(invoker->withParams());

    /**
     * Parameters or not, we must in any case create a new stack frame
     * for the template invocation since otherwise we will trash our existing
     * variables. Hence it's as with calling user functions.
     *
     * This is especially reproducible with recursive functions.
     */
    DynamicContext::Ptr newStack(context->createStack());

    /* We have no parameters, and we have no further error checking to
     * do in the case of not being xsl:apply-templates, so we need to do nothing. */
    if(templateParameters.isEmpty() && (!isCallTemplate || withParams.isEmpty()))
        return newStack;

    const DynamicContext::TemplateParameterHash hashedParams(parametersAsHash());
    DynamicContext::TemplateParameterHash sewnTogether(hashedParams);

    const DynamicContext::TemplateParameterHash::iterator end(sewnTogether.end());

    for(DynamicContext::TemplateParameterHash::iterator it(sewnTogether.begin());
        it != end;
        ++it)
    {
        Expression::Ptr &param = it.value();

        WithParam::Ptr &withParam = withParams[it.key()];

        if(withParam)
            param = Expression::Ptr(new DynamicContextStore(withParam->sourceExpression(), context));
        else if(!param)
        {
            /* Ops, no xsl:with-param and no default value to cover up for it.
             */
            context->error(QtXmlPatterns::tr("The parameter %1 is required, but no corresponding %2 is supplied.")
                                             .arg(formatKeyword(context->namePool(), it.key()),
                                                  formatKeyword(QLatin1String("xsl:with-param"))),
                           ReportContext::XTSE0690,
                           this);
        }
    }

    if(isCallTemplate)
    {
        /* Find xsl:with-param that has no corresponding xsl:param. */
        /* Optimization: candidate for threading? */

        const WithParam::Hash::const_iterator end(withParams.constEnd());

        for(WithParam::Hash::const_iterator it(withParams.constBegin()); it != end; ++it)
        {
            if(!hashedParams.contains(it.key()))
                raiseXTSE0680(context, it.key(), this);
        }

    }

    newStack->templateParameterStore() = sewnTogether;
    return newStack;
}

void Template::compileParameters(const StaticContext::Ptr &context)
{
    Q_ASSERT(context);

    const int len = templateParameters.count();

    for(int i = 0; i < len; ++i)
    {
        const VariableDeclaration::Ptr &at = templateParameters.at(i);

        /* If our value is required, we don't have a default value. */
        if(at->expression())
        {
            // TODO why do we pass in its own type here?
            at->setExpression(at->expression()->typeCheck(context, at->expression()->staticType()));

            at->setExpression(at->expression()->compress(context));
        }
    }
}

Expression::Properties Template::properties() const
{
    return Expression::DisableElimination; /* We're having issues with recursion detection, so this path currently loops infintely. */

    Expression::Properties collect(body->properties());

    VariableDeclaration::List::const_iterator end(templateParameters.constEnd());

    for(VariableDeclaration::List::const_iterator it(templateParameters.constBegin());
        it != end;
        ++it)
    {
        if((*it)->expression())
            collect |= (*it)->expression()->properties();
    }

    // TODO simplify.
    return collect & (Expression::RequiresFocus | Expression::IsEvaluated | Expression::DisableElimination);
}

Expression::Properties Template::dependencies() const
{
    return Expression::DisableElimination; /* We're having issues with recursion detection, so this path currently loops infintely. */

    Expression::Properties collect(body->dependencies());

    VariableDeclaration::List::const_iterator end(templateParameters.constEnd());

    for(VariableDeclaration::List::const_iterator it(templateParameters.constBegin());
        it != end;
        ++it)
    {
        if((*it)->expression())
            collect |= (*it)->expression()->dependencies();
    }

    return collect & (Expression::RequiresFocus | Expression::IsEvaluated | Expression::DisableElimination);
}

QT_END_NAMESPACE