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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
/*
Implementation of an XPath LocationStep
*/
#include "txExpr.h"
#include "txIXPathContext.h"
#include "txNodeSet.h"
#include "txXPathTreeWalker.h"
//-----------------------------/
//- Virtual methods from Expr -/
//-----------------------------/
/**
* Evaluates this Expr based on the given context node and processor state
* @param context the context node for evaluation of this Expr
* @param ps the ProcessorState containing the stack information needed
* for evaluation
* @return the result of the evaluation
* @see Expr
**/
nsresult LocationStep::evaluate(txIEvalContext* aContext,
txAExprResult** aResult) {
NS_ASSERTION(aContext, "internal error");
*aResult = nullptr;
RefPtr<txNodeSet> nodes;
nsresult rv = aContext->recycler()->getNodeSet(getter_AddRefs(nodes));
NS_ENSURE_SUCCESS(rv, rv);
txXPathTreeWalker walker(aContext->getContextNode());
switch (mAxisIdentifier) {
case ANCESTOR_AXIS: {
if (!walker.moveToParent()) {
break;
}
[[fallthrough]];
}
case ANCESTOR_OR_SELF_AXIS: {
nodes->setReverse();
do {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
} while (walker.moveToParent());
break;
}
case ATTRIBUTE_AXIS: {
if (!walker.moveToFirstAttribute()) {
break;
}
do {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
} while (walker.moveToNextAttribute());
break;
}
case DESCENDANT_OR_SELF_AXIS: {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
[[fallthrough]];
}
case DESCENDANT_AXIS: {
rv = appendMatchingDescendants(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
break;
}
case FOLLOWING_AXIS: {
if (txXPathNodeUtils::isAttribute(walker.getCurrentPosition())) {
walker.moveToParent();
rv = appendMatchingDescendants(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
}
bool cont = true;
while (!walker.moveToNextSibling()) {
if (!walker.moveToParent()) {
cont = false;
break;
}
}
while (cont) {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
rv = appendMatchingDescendants(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
while (!walker.moveToNextSibling()) {
if (!walker.moveToParent()) {
cont = false;
break;
}
}
}
break;
}
case FOLLOWING_SIBLING_AXIS: {
while (walker.moveToNextSibling()) {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
}
break;
}
case NAMESPACE_AXIS: //-- not yet implemented
#if 0
// XXX DEBUG OUTPUT
cout << "namespace axis not yet implemented"<<endl;
#endif
break;
case PARENT_AXIS: {
if (walker.moveToParent()) {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
}
break;
}
case PRECEDING_AXIS: {
nodes->setReverse();
bool cont = true;
while (!walker.moveToPreviousSibling()) {
if (!walker.moveToParent()) {
cont = false;
break;
}
}
while (cont) {
rv = appendMatchingDescendantsRev(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
while (!walker.moveToPreviousSibling()) {
if (!walker.moveToParent()) {
cont = false;
break;
}
}
}
break;
}
case PRECEDING_SIBLING_AXIS: {
nodes->setReverse();
while (walker.moveToPreviousSibling()) {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
}
break;
}
case SELF_AXIS: {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
break;
}
default: // Children Axis
{
if (!walker.moveToFirstChild()) {
break;
}
do {
rv = appendIfMatching(walker, aContext, nodes);
NS_ENSURE_SUCCESS(rv, rv);
} while (walker.moveToNextSibling());
break;
}
}
// Apply predicates
if (!isEmpty()) {
rv = evaluatePredicates(nodes, aContext);
NS_ENSURE_SUCCESS(rv, rv);
}
nodes->unsetReverse();
NS_ADDREF(*aResult = nodes);
return NS_OK;
}
nsresult LocationStep::appendIfMatching(const txXPathTreeWalker& aWalker,
txIMatchContext* aContext,
txNodeSet* aNodes) {
bool matched;
const txXPathNode& child = aWalker.getCurrentPosition();
nsresult rv = mNodeTest->matches(child, aContext, matched);
NS_ENSURE_SUCCESS(rv, rv);
if (matched) {
aNodes->append(child);
}
return NS_OK;
}
nsresult LocationStep::appendMatchingDescendants(
const txXPathTreeWalker& aWalker, txIMatchContext* aContext,
txNodeSet* aNodes) {
txXPathTreeWalker walker(aWalker);
if (!walker.moveToFirstChild()) {
return NS_OK;
}
do {
nsresult rv = appendIfMatching(walker, aContext, aNodes);
NS_ENSURE_SUCCESS(rv, rv);
rv = appendMatchingDescendants(walker, aContext, aNodes);
NS_ENSURE_SUCCESS(rv, rv);
} while (walker.moveToNextSibling());
return NS_OK;
}
nsresult LocationStep::appendMatchingDescendantsRev(
const txXPathTreeWalker& aWalker, txIMatchContext* aContext,
txNodeSet* aNodes) {
txXPathTreeWalker walker(aWalker);
if (!walker.moveToLastChild()) {
return NS_OK;
}
do {
nsresult rv = appendMatchingDescendantsRev(walker, aContext, aNodes);
NS_ENSURE_SUCCESS(rv, rv);
rv = appendIfMatching(walker, aContext, aNodes);
NS_ENSURE_SUCCESS(rv, rv);
} while (walker.moveToPreviousSibling());
return NS_OK;
}
Expr::ExprType LocationStep::getType() { return LOCATIONSTEP_EXPR; }
TX_IMPL_EXPR_STUBS_BASE(LocationStep, NODESET_RESULT)
Expr* LocationStep::getSubExprAt(uint32_t aPos) {
return PredicateList::getSubExprAt(aPos);
}
void LocationStep::setSubExprAt(uint32_t aPos, Expr* aExpr) {
PredicateList::setSubExprAt(aPos, aExpr);
}
bool LocationStep::isSensitiveTo(ContextSensitivity aContext) {
return (aContext & NODE_CONTEXT) || mNodeTest->isSensitiveTo(aContext) ||
PredicateList::isSensitiveTo(aContext);
}
#ifdef TX_TO_STRING
void LocationStep::toString(nsAString& str) {
switch (mAxisIdentifier) {
case ANCESTOR_AXIS:
str.AppendLiteral("ancestor::");
break;
case ANCESTOR_OR_SELF_AXIS:
str.AppendLiteral("ancestor-or-self::");
break;
case ATTRIBUTE_AXIS:
str.Append(char16_t('@'));
break;
case DESCENDANT_AXIS:
str.AppendLiteral("descendant::");
break;
case DESCENDANT_OR_SELF_AXIS:
str.AppendLiteral("descendant-or-self::");
break;
case FOLLOWING_AXIS:
str.AppendLiteral("following::");
break;
case FOLLOWING_SIBLING_AXIS:
str.AppendLiteral("following-sibling::");
break;
case NAMESPACE_AXIS:
str.AppendLiteral("namespace::");
break;
case PARENT_AXIS:
str.AppendLiteral("parent::");
break;
case PRECEDING_AXIS:
str.AppendLiteral("preceding::");
break;
case PRECEDING_SIBLING_AXIS:
str.AppendLiteral("preceding-sibling::");
break;
case SELF_AXIS:
str.AppendLiteral("self::");
break;
default:
break;
}
NS_ASSERTION(mNodeTest, "mNodeTest is null, that's verboten");
mNodeTest->toString(str);
PredicateList::toString(str);
}
#endif