tor-browser

txPathExpr.cpp (6817B)

---

/* -*- 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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "txExpr.h"
#include "txNodeSet.h"
#include "txNodeSetContext.h"
#include "txSingleNodeContext.h"
#include "txXMLUtils.h"
#include "txXPathTreeWalker.h"

using mozilla::WrapUnique;

//------------/
//- PathExpr -/
//------------/

/**
* Adds the Expr to this PathExpr
* @param expr the Expr to add to this PathExpr
**/
void PathExpr::addExpr(Expr* aExpr, PathOperator aPathOp) {
 NS_ASSERTION(!mItems.IsEmpty() || aPathOp == RELATIVE_OP,
              "First step has to be relative in PathExpr");
 PathExprItem* pxi = mItems.AppendElement();
 pxi->expr = WrapUnique(aExpr);
 pxi->pathOp = aPathOp;
}

//-----------------------------/
//- 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 ContextState containing the stack information needed
* for evaluation
* @return the result of the evaluation
**/
nsresult PathExpr::evaluate(txIEvalContext* aContext, txAExprResult** aResult) {
 *aResult = nullptr;

 // We need to evaluate the first step with the current context since it
 // can depend on the context size and position. For example:
 // key('books', concat('book', position()))
 RefPtr<txAExprResult> res;
 nsresult rv = mItems[0].expr->evaluate(aContext, getter_AddRefs(res));
 NS_ENSURE_SUCCESS(rv, rv);

 NS_ENSURE_TRUE(res->getResultType() == txAExprResult::NODESET,
                NS_ERROR_XSLT_NODESET_EXPECTED);

 RefPtr<txNodeSet> nodes =
     static_cast<txNodeSet*>(static_cast<txAExprResult*>(res));
 if (nodes->isEmpty()) {
   res.forget(aResult);

   return NS_OK;
 }
 res = nullptr;  // To allow recycling

 // Evaluate remaining steps
 uint32_t i, len = mItems.Length();
 for (i = 1; i < len; ++i) {
   PathExprItem& pxi = mItems[i];
   RefPtr<txNodeSet> tmpNodes;
   txNodeSetContext eContext(nodes, aContext);
   while (eContext.hasNext()) {
     eContext.next();

     RefPtr<txNodeSet> resNodes;
     if (pxi.pathOp == DESCENDANT_OP) {
       rv = aContext->recycler()->getNodeSet(getter_AddRefs(resNodes));
       NS_ENSURE_SUCCESS(rv, rv);

       rv = evalDescendants(pxi.expr.get(), eContext.getContextNode(),
                            &eContext, resNodes);
       NS_ENSURE_SUCCESS(rv, rv);
     } else {
       RefPtr<txAExprResult> res;
       rv = pxi.expr->evaluate(&eContext, getter_AddRefs(res));
       NS_ENSURE_SUCCESS(rv, rv);

       if (res->getResultType() != txAExprResult::NODESET) {
         // XXX ErrorReport: report nonnodeset error
         return NS_ERROR_XSLT_NODESET_EXPECTED;
       }
       resNodes = static_cast<txNodeSet*>(static_cast<txAExprResult*>(res));
     }

     if (tmpNodes) {
       if (!resNodes->isEmpty()) {
         RefPtr<txNodeSet> oldSet;
         oldSet.swap(tmpNodes);
         rv = aContext->recycler()->getNonSharedNodeSet(
             oldSet, getter_AddRefs(tmpNodes));
         NS_ENSURE_SUCCESS(rv, rv);

         oldSet.swap(resNodes);
         rv = aContext->recycler()->getNonSharedNodeSet(
             oldSet, getter_AddRefs(resNodes));
         NS_ENSURE_SUCCESS(rv, rv);

         tmpNodes->addAndTransfer(resNodes);
       }
     } else {
       tmpNodes = resNodes;
     }
   }
   nodes = tmpNodes;
   if (nodes->isEmpty()) {
     break;
   }
 }

 *aResult = nodes;
 NS_ADDREF(*aResult);

 return NS_OK;
}  //-- evaluate

/**
* Selects from the descendants of the context node
* all nodes that match the Expr
**/
nsresult PathExpr::evalDescendants(Expr* aStep, const txXPathNode& aNode,
                                  txIMatchContext* aContext,
                                  txNodeSet* resNodes) {
 txSingleNodeContext eContext(aNode, aContext);
 RefPtr<txAExprResult> res;
 nsresult rv = aStep->evaluate(&eContext, getter_AddRefs(res));
 NS_ENSURE_SUCCESS(rv, rv);

 if (res->getResultType() != txAExprResult::NODESET) {
   // XXX ErrorReport: report nonnodeset error
   return NS_ERROR_XSLT_NODESET_EXPECTED;
 }

 txNodeSet* oldSet = static_cast<txNodeSet*>(static_cast<txAExprResult*>(res));
 RefPtr<txNodeSet> newSet;
 rv =
     aContext->recycler()->getNonSharedNodeSet(oldSet, getter_AddRefs(newSet));
 NS_ENSURE_SUCCESS(rv, rv);

 resNodes->addAndTransfer(newSet);

 bool filterWS;
 rv = aContext->isStripSpaceAllowed(aNode, filterWS);
 NS_ENSURE_SUCCESS(rv, rv);

 txXPathTreeWalker walker(aNode);
 if (!walker.moveToFirstChild()) {
   return NS_OK;
 }

 do {
   const txXPathNode& node = walker.getCurrentPosition();
   if (!(filterWS && txXPathNodeUtils::isText(node) &&
         txXPathNodeUtils::isWhitespace(node))) {
     rv = evalDescendants(aStep, node, aContext, resNodes);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 } while (walker.moveToNextSibling());

 return NS_OK;
}  //-- evalDescendants

Expr::ExprType PathExpr::getType() { return PATH_EXPR; }

TX_IMPL_EXPR_STUBS_BASE(PathExpr, NODESET_RESULT)

Expr* PathExpr::getSubExprAt(uint32_t aPos) {
 return aPos < mItems.Length() ? mItems[aPos].expr.get() : nullptr;
}
void PathExpr::setSubExprAt(uint32_t aPos, Expr* aExpr) {
 NS_ASSERTION(aPos < mItems.Length(), "setting bad subexpression index");
 (void)mItems[aPos].expr.release();
 mItems[aPos].expr = WrapUnique(aExpr);
}

bool PathExpr::isSensitiveTo(ContextSensitivity aContext) {
 if (mItems[0].expr->isSensitiveTo(aContext)) {
   return true;
 }

 // We're creating a new node/nodeset so we can ignore those bits.
 Expr::ContextSensitivity context =
     aContext & ~(Expr::NODE_CONTEXT | Expr::NODESET_CONTEXT);
 if (context == NO_CONTEXT) {
   return false;
 }

 uint32_t i, len = mItems.Length();
 for (i = 0; i < len; ++i) {
   NS_ASSERTION(!mItems[i].expr->isSensitiveTo(Expr::NODESET_CONTEXT),
                "Step cannot depend on nodeset-context");
   if (mItems[i].expr->isSensitiveTo(context)) {
     return true;
   }
 }

 return false;
}

#ifdef TX_TO_STRING
void PathExpr::toString(nsAString& dest) {
 if (!mItems.IsEmpty()) {
   NS_ASSERTION(mItems[0].pathOp == RELATIVE_OP,
                "First step should be relative");
   mItems[0].expr->toString(dest);
 }

 uint32_t i, len = mItems.Length();
 for (i = 1; i < len; ++i) {
   switch (mItems[i].pathOp) {
     case DESCENDANT_OP:
       dest.AppendLiteral("//");
       break;
     case RELATIVE_OP:
       dest.Append(char16_t('/'));
       break;
   }
   mItems[i].expr->toString(dest);
 }
}
#endif