| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // 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.google.devtools.build.lib.query2.engine; |
| |
| import com.google.common.base.Predicate; |
| import com.google.common.base.Predicates; |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.Iterables; |
| import com.google.common.collect.Sets; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Argument; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ArgumentType; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction; |
| |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| import java.util.concurrent.ForkJoinPool; |
| |
| /** |
| * Implementation of the <code>allpaths()</code> function. |
| */ |
| public class AllPathsFunction implements QueryFunction { |
| AllPathsFunction() { |
| } |
| |
| @Override |
| public String getName() { |
| return "allpaths"; |
| } |
| |
| @Override |
| public int getMandatoryArguments() { |
| return 2; |
| } |
| |
| @Override |
| public List<ArgumentType> getArgumentTypes() { |
| return ImmutableList.of(ArgumentType.EXPRESSION, ArgumentType.EXPRESSION); |
| } |
| |
| @Override |
| public <T> void eval( |
| QueryEnvironment<T> env, |
| VariableContext<T> context, |
| QueryExpression expression, |
| List<Argument> args, |
| Callback<T> callback) throws QueryException, InterruptedException { |
| |
| Set<T> fromValue = QueryUtil.evalAll(env, context, args.get(0).getExpression()); |
| Set<T> toValue = QueryUtil.evalAll(env, context, args.get(1).getExpression()); |
| |
| // Algorithm: compute "reachableFromX", the forward transitive closure of |
| // the "from" set, then find the intersection of "reachableFromX" with the |
| // reverse transitive closure of the "to" set. The reverse transitive |
| // closure and intersection operations are interleaved for efficiency. |
| // "result" holds the intersection. |
| |
| env.buildTransitiveClosure(expression, fromValue, Integer.MAX_VALUE); |
| |
| Set<T> reachableFromX = env.getTransitiveClosure(fromValue); |
| Predicate<T> reachable = Predicates.in(reachableFromX); |
| Uniquifier<T> uniquifier = env.createUniquifier(); |
| Collection<T> result = uniquifier.unique(intersection(reachableFromX, toValue)); |
| callback.process(result); |
| Collection<T> worklist = result; |
| while (!worklist.isEmpty()) { |
| Collection<T> reverseDeps = env.getReverseDeps(worklist); |
| worklist = uniquifier.unique(Iterables.filter(reverseDeps, reachable)); |
| callback.process(worklist); |
| } |
| } |
| |
| @Override |
| public <T> void parEval( |
| QueryEnvironment<T> env, |
| VariableContext<T> context, |
| QueryExpression expression, |
| List<Argument> args, |
| ThreadSafeCallback<T> callback, |
| ForkJoinPool forkJoinPool) throws QueryException, InterruptedException { |
| eval(env, context, expression, args, callback); |
| } |
| |
| /** |
| * Returns a (new, mutable, unordered) set containing the intersection of the |
| * two specified sets. |
| */ |
| private static <T> Set<T> intersection(Set<T> x, Set<T> y) { |
| Set<T> result = new HashSet<>(); |
| if (x.size() > y.size()) { |
| Sets.intersection(y, x).copyInto(result); |
| } else { |
| Sets.intersection(x, y).copyInto(result); |
| } |
| return result; |
| } |
| } |