// 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.Function;
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 com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskFuture;
import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ThreadSafeMutableSet;
import java.util.List;
/**
* 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.
*
*
expr ::= RDEPS '(' expr ',' expr ')'
* | RDEPS '(' expr ',' expr ',' WORD ')'
*/
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 getArgumentTypes() {
return ImmutableList.builder()
.add(ArgumentType.EXPRESSION).addAll(super.getArgumentTypes()).build();
}
@Override
public QueryTaskFuture eval(
QueryEnvironment env,
QueryExpressionContext context,
QueryExpression expression,
List args,
Callback callback) {
boolean isDepthUnbounded = args.size() == 2;
int depth = isDepthUnbounded ? Integer.MAX_VALUE : args.get(2).getInteger();
QueryExpression universeExpression = args.get(0).getExpression();
QueryExpression argumentExpression = args.get(1).getExpression();
if (env instanceof StreamableQueryEnvironment) {
StreamableQueryEnvironment streamableEnv = (StreamableQueryEnvironment) env;
return isDepthUnbounded
? streamableEnv.getRdepsUnboundedParallel(
argumentExpression, universeExpression, context, callback)
: streamableEnv.getRdepsBoundedParallel(
argumentExpression, depth, universeExpression, context, callback);
} else {
return evalWithBoundedDepth(
env, expression, context, argumentExpression, depth, universeExpression, callback);
}
}
/**
* Compute the transitive closure of the universe, then breadth-first search from the argument
* towards the universe while staying within the transitive closure.
*/
private static QueryTaskFuture evalWithBoundedDepth(
QueryEnvironment env,
QueryExpression rdepsFunctionExpressionForErrorMessages,
QueryExpressionContext context,
QueryExpression argumentExpression,
int depth,
QueryExpression universeExpression,
Callback callback) {
QueryTaskFuture> universeValueFuture =
QueryUtil.evalAll(env, context, universeExpression);
Function, QueryTaskFuture> evalInUniverseAsyncFunction =
universeValue -> {
Predicate universe;
try {
env.buildTransitiveClosure(
rdepsFunctionExpressionForErrorMessages, universeValue, Integer.MAX_VALUE);
universe = Predicates.in(env.getTransitiveClosure(universeValue, context));
} catch (InterruptedException e) {
return env.immediateCancelledFuture();
} catch (QueryException e) {
return env.immediateFailedFuture(e);
}
return AllRdepsFunction.eval(env, argumentExpression, universe, context, callback, depth);
};
return env.transformAsync(universeValueFuture, evalInUniverseAsyncFunction);
}
}