source: trunk/src/xmlpatterns/expr/qoptimizationpasses.cpp@ 703

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#include "qcommonsequencetypes_p.h"
#include "qoptimizerblocks_p.h"

#include "qoptimizationpasses_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

OptimizationPass::List OptimizationPasses::comparisonPasses;
OptimizationPass::List OptimizationPasses::forPasses;
OptimizationPass::List OptimizationPasses::ifThenPasses;
OptimizationPass::List OptimizationPasses::notFN;

void OptimizationPasses::Coordinator::init()
{
    static bool isInitialized = false; // STATIC DATA

    if(isInitialized)
        return;

    isInitialized = true;

    /* Note, below is many of the building blocks re-used in several passes
     * in order to reduce memory use. Thus, when changing one building block
     * it potentially affects many passes. */

    /* ****************************************************** */
    /* Rewrite "count(<expr>) ge 1" into "exists(<expr>)" */
    OptimizationPass::ExpressionMarker firstFirstChild;
    firstFirstChild.append(0);
    firstFirstChild.append(0);

    ExpressionIdentifier::List geOpIDs;
    const ExpressionIdentifier::Ptr countFN(new ByIDIdentifier(Expression::IDCountFN));
    geOpIDs.append(countFN);
    geOpIDs.append(ExpressionIdentifier::Ptr(new IntegerIdentifier(1)));

    QVector<Expression::ID> geMatcher;
    geMatcher.append(Expression::IDValueComparison);
    geMatcher.append(Expression::IDGeneralComparison);

    const ExpressionIdentifier::Ptr ge(new ComparisonIdentifier(geMatcher,
                                                                AtomicComparator::OperatorGreaterOrEqual));

    const ExpressionCreator::Ptr existsFN(new ByIDCreator(Expression::IDExistsFN));
    const OptimizationPass::Ptr geToExists(new OptimizationPass(ge, geOpIDs, firstFirstChild, existsFN));
    comparisonPasses.append(geToExists);
    /* ****************************************************** */

    /* ****************************************************** */
    /* Rewrite "count(<expr>) gt 0" into "exists(<expr>)" */
    ExpressionIdentifier::List countAndIntZero;