com.google.devtools.build.lib.query2.engine.RdepsFunction.java Source code

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Here is the source code for com.google.devtools.build.lib.query2.engine.RdepsFunction.java

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// 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.devtools.build.lib.query2.engine.QueryEnvironment.Argument;
import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ArgumentType;

import java.util.List;
import java.util.Set;

/**
 * An "rdeps" query expression, which computes the reverse dependencies of the argument within the
 * transitive closure of the universe. An optional integer-literal third argument may be
 * specified; its value bounds the search from the arguments.
 *
 * <pre>expr ::= RDEPS '(' expr ',' expr ')'</pre>
 * <pre>       | RDEPS '(' expr ',' expr ',' WORD ')'</pre>
 */
public final class RdepsFunction extends AllRdepsFunction {
    public RdepsFunction() {
    }

    @Override
    public String getName() {
        return "rdeps";
    }

    @Override
    public int getMandatoryArguments() {
        return super.getMandatoryArguments() + 1; // +1 for the universe.
    }

    @Override
    public List<ArgumentType> getArgumentTypes() {
        return ImmutableList.<ArgumentType>builder().add(ArgumentType.EXPRESSION).addAll(super.getArgumentTypes())
                .build();
    }

    /**
     * Compute the transitive closure of the universe, then breadth-first search from the argument
     * towards the universe while staying within the transitive closure.
     */
    @Override
    public <T> void eval(QueryEnvironment<T> env, VariableContext<T> context, QueryExpression expression,
            List<Argument> args, Callback<T> callback) throws QueryException, InterruptedException {
        Set<T> universeValue = QueryUtil.evalAll(env, context, args.get(0).getExpression());
        env.buildTransitiveClosure(expression, universeValue, Integer.MAX_VALUE);

        Predicate<T> universe = Predicates.in(env.getTransitiveClosure(universeValue));
        eval(env, context, args.subList(1, args.size()), callback, universe);
    }
}