/*
* Copyright 2003-2014 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.mps.generator.impl;
import jetbrains.mps.generator.impl.FastRuleFinder.BlockedReductionsData;
import jetbrains.mps.generator.runtime.TemplateReductionRule;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.mps.openapi.model.SNode;
import java.util.ArrayDeque;
import java.util.Deque;
/**
* Tracks history of applied reductions.
* Intended to be used from a single thread.
*
* XXX Perhaps, shall also absorb tryToReduce(ReductionRule[], TemplateContext)
*
* @author Artem Tikhomirov
*/
final class ReductionTrack {
private final BlockedReductionsData myReductionsData;
private final Deque<ReductionContext> myReductionStack;
public ReductionTrack(@NotNull BlockedReductionsData reductionsData) {
myReductionsData = reductionsData;
myReductionStack = new ArrayDeque<ReductionContext>(20);
myReductionStack.push(new ReductionContext());
}
/**
* prevents applying of reduction rules which have already been applied to the input node.
*/
public void blockReductionsForCopiedNode(SNode inputNode, SNode outputNode) {
myReductionsData.blockReductionsForCopiedNode(inputNode, outputNode, actual());
}
public boolean isReductionBlocked(SNode node, TemplateReductionRule rule) {
return myReductionsData.isReductionBlocked(node, rule) || actual().isBlocked(node, rule);
}
public ReductionContext actual() {
return myReductionStack.peek();
}
public void enter(SNode inputNode, TemplateReductionRule rule) {
myReductionStack.push(new ReductionContext(actual(), inputNode, rule));
}
public void leave() {
myReductionStack.pop();
}
}