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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "txPatternOptimizer.h"
#include "txXSLTPatterns.h"
void txPatternOptimizer::optimize(txPattern* aInPattern,
txPattern** aOutPattern) {
*aOutPattern = nullptr;
// First optimize sub expressions
uint32_t i = 0;
Expr* subExpr;
while ((subExpr = aInPattern->getSubExprAt(i))) {
Expr* newExpr = nullptr;
mXPathOptimizer.optimize(subExpr, &newExpr);
if (newExpr) {
delete subExpr;
aInPattern->setSubExprAt(i, newExpr);
}
++i;
}
// Then optimize sub patterns
txPattern* subPattern;
i = 0;
while ((subPattern = aInPattern->getSubPatternAt(i))) {
txPattern* newPattern = nullptr;
optimize(subPattern, &newPattern);
if (newPattern) {
delete subPattern;
aInPattern->setSubPatternAt(i, newPattern);
}
++i;
}
// Finally see if current pattern can be optimized
switch (aInPattern->getType()) {
case txPattern::STEP_PATTERN:
optimizeStep(aInPattern, aOutPattern);
return;
default:
break;
}
}
void txPatternOptimizer::optimizeStep(txPattern* aInPattern,
txPattern** aOutPattern) {
txStepPattern* step = static_cast<txStepPattern*>(aInPattern);
// Test for predicates that can be combined into the nodetest
Expr* pred;
while ((pred = step->getSubExprAt(0)) &&
!pred->canReturnType(Expr::NUMBER_RESULT) &&
!pred->isSensitiveTo(Expr::NODESET_CONTEXT)) {
txNodeTest* predTest = new txPredicatedNodeTest(step->getNodeTest(), pred);
step->dropFirst();
step->setNodeTest(predTest);
}
}