| // 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.collect.ImmutableList; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.Sets; |
| import com.google.common.collect.Sets.SetView; |
| 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.List; |
| import java.util.Set; |
| import java.util.concurrent.ForkJoinPool; |
| |
| /** |
| * A somepath(x, y) query expression, which computes the set of nodes |
| * on some arbitrary path from a target in set x to a target in set y. |
| * |
| * <pre>expr ::= SOMEPATH '(' expr ',' expr ')'</pre> |
| */ |
| class SomePathFunction implements QueryFunction { |
| SomePathFunction() { |
| } |
| |
| @Override |
| public String getName() { |
| return "somepath"; |
| } |
| |
| @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, |
| final 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()); |
| |
| // Implementation strategy: for each x in "from", compute its forward |
| // transitive closure. If it intersects "to", then do a path search from x |
| // to an arbitrary node in the intersection, and return the path. This |
| // avoids computing the full transitive closure of "from" in some cases. |
| |
| env.buildTransitiveClosure(expression, fromValue, Integer.MAX_VALUE); |
| |
| // This set contains all nodes whose TC does not intersect "toValue". |
| Uniquifier<T> uniquifier = env.createUniquifier(); |
| |
| for (T x : uniquifier.unique(fromValue)) { |
| Set<T> xtc = env.getTransitiveClosure(ImmutableSet.of(x)); |
| SetView<T> result; |
| if (xtc.size() > toValue.size()) { |
| result = Sets.intersection(toValue, xtc); |
| } else { |
| result = Sets.intersection(xtc, toValue); |
| } |
| if (!result.isEmpty()) { |
| callback.process(env.getNodesOnPath(x, result.iterator().next())); |
| return; |
| } |
| uniquifier.unique(xtc); |
| } |
| callback.process(ImmutableSet.<T>of()); |
| } |
| |
| @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); |
| } |
| } |