| /* |
| * Copyright 2012-present Facebook, Inc. |
| * |
| * 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 com.facebook.buck.rules; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Lists; |
| import com.google.common.collect.Sets; |
| |
| import java.util.Queue; |
| import java.util.Set; |
| |
| /** |
| * Performs a breadth-first traversal of a {@link BuildRule}'s dependencies. |
| */ |
| public abstract class AbstractDependencyVisitor { |
| |
| private final Queue<BuildRule> toExplore; |
| private final Set<BuildRule> explored; |
| |
| public AbstractDependencyVisitor(BuildRule initialRule) { |
| this(initialRule, false /* excludeRoot */); |
| } |
| |
| public AbstractDependencyVisitor(BuildRule initialRule, boolean excludeRoot) { |
| Preconditions.checkNotNull(initialRule); |
| this.toExplore = Lists.newLinkedList(); |
| if (excludeRoot) { |
| this.toExplore.addAll(initialRule.getDeps()); |
| } else { |
| this.toExplore.add(initialRule); |
| } |
| this.explored = Sets.newHashSet(); |
| } |
| |
| public final void start() { |
| while (!toExplore.isEmpty()) { |
| BuildRule currentRule = toExplore.remove(); |
| if (explored.contains(currentRule)) { |
| continue; |
| } |
| |
| boolean shouldVisitDeps = visit(currentRule); |
| explored.add(currentRule); |
| |
| if (shouldVisitDeps) { |
| for (BuildRule dep : currentRule.getDeps()) { |
| if (!explored.contains(dep)) { |
| toExplore.add(dep); |
| } |
| } |
| } |
| } |
| |
| onComplete(); |
| } |
| |
| /** Override this method with any logic that should be run when {@link #start()} completes. */ |
| protected void onComplete() { |
| |
| } |
| |
| /** |
| * @param rule Visited build rule |
| * @return whether to traverse the deps of the current rule |
| */ |
| public abstract boolean visit(BuildRule rule); |
| } |