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