dom/xslt/xpath/txPredicateList.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "txExpr.h"
   7 #include "txNodeSet.h"
   8 #include "txNodeSetContext.h"
   9
  10 /*
  11  * Represents an ordered list of Predicates,
  12  * for use with Step and Filter Expressions
  13  */
  14
  15 nsresult PredicateList::evaluatePredicates(txNodeSet* nodes,
  16                                            txIMatchContext* aContext) {
  17   NS_ASSERTION(nodes, "called evaluatePredicates with nullptr NodeSet");
  18   nsresult rv = NS_OK;
  19
  20   uint32_t i, len = mPredicates.Length();
  21   for (i = 0; i < len && !nodes->isEmpty(); ++i) {
  22     txNodeSetContext predContext(nodes, aContext);
  23     /*
  24      * add nodes to newNodes that match the expression
  25      * or, if the result is a number, add the node with the right
  26      * position
  27      */
  28     int32_t index = 0;
  29     while (predContext.hasNext()) {
  30       predContext.next();
  31       RefPtr<txAExprResult> exprResult;
  32       rv = mPredicates[i]->evaluate(&predContext, getter_AddRefs(exprResult));
  33       NS_ENSURE_SUCCESS(rv, rv);
  34
  35       // handle default, [position() == numberValue()]
  36       if (exprResult->getResultType() == txAExprResult::NUMBER) {
  37         if ((double)predContext.position() == exprResult->numberValue()) {
  38           nodes->mark(index);
  39         }
  40       } else if (exprResult->booleanValue()) {
  41         nodes->mark(index);
  42       }
  43       ++index;
  44     }
  45     // sweep the non-marked nodes
  46     nodes->sweep();
  47   }
  48
  49   return NS_OK;
  50 }
  51
  52 bool PredicateList::isSensitiveTo(Expr::ContextSensitivity aContext) {
  53   // We're creating a new node/nodeset so we can ignore those bits.
  54   Expr::ContextSensitivity context =
  55       aContext & ~(Expr::NODE_CONTEXT | Expr::NODESET_CONTEXT);
  56   if (context == Expr::NO_CONTEXT) {
  57     return false;
  58   }
  59
  60   uint32_t i, len = mPredicates.Length();
  61   for (i = 0; i < len; ++i) {
  62     if (mPredicates[i]->isSensitiveTo(context)) {
  63       return true;
  64     }
  65   }
  66
  67   return false;
  68 }
  69
  70 #ifdef TX_TO_STRING
  71 void PredicateList::toString(nsAString& dest) {
  72   for (uint32_t i = 0; i < mPredicates.Length(); ++i) {
  73     dest.Append(char16_t('['));
  74     mPredicates[i]->toString(dest);
  75     dest.Append(char16_t(']'));
  76   }
  77 }
  78 #endif