// Copyright 2015 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.Optional;
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.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 com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskFuture;
import java.util.ArrayList;
import java.util.List;
/**
* An "allrdeps" query expression, which computes the reverse dependencies of the argument within
* the currently known universe. An optional integer-literal second argument may be specified; its
* value bounds the search from the arguments.
*
*
expr ::= ALLRDEPS '(' expr ')'
* | ALLRDEPS '(' expr ',' WORD ')'
*/
// Public because SkyQueryEnvironment needs to refer to it directly.
public class AllRdepsFunction implements QueryFunction {
@Override
public String getName() {
return "allrdeps";
}
@Override
public int getMandatoryArguments() {
return 1; // last argument is optional
}
@Override
public List getArgumentTypes() {
return ImmutableList.of(ArgumentType.EXPRESSION, ArgumentType.INTEGER);
}
@Override
public QueryTaskFuture eval(
QueryEnvironment env,
VariableContext context,
QueryExpression expression,
List args,
Callback callback) {
return evalRdeps(env, context, args, callback, Optional.>absent());
}
/** Evaluates rdeps query. */
public static QueryTaskFuture eval(
final QueryEnvironment env,
QueryExpression expression,
final Predicate universe,
VariableContext context,
final Callback callback,
final int depth) {
final MinDepthUniquifier minDepthUniquifier = env.createMinDepthUniquifier();
return env.eval(
expression,
context,
new Callback() {
@Override
public void process(Iterable partialResult)
throws QueryException, InterruptedException {
Iterable current = partialResult;
// We need to iterate depthBound + 1 times.
for (int i = 0; i <= depth; i++) {
List next = new ArrayList<>();
// Restrict to nodes satisfying the universe predicate.
Iterable currentInUniverse = Iterables.filter(current, universe);
// Filter already visited nodes: if we see a node in a later round, then we don't
// need to visit it again, because the depth at which we see it must be greater
// than or equal to the last visit.
Iterables.addAll(
next,
env.getReverseDeps(
minDepthUniquifier.uniqueAtDepthLessThanOrEqualTo(currentInUniverse, i)));
callback.process(currentInUniverse);
if (next.isEmpty()) {
// Exit when there are no more nodes to visit.
break;
}
current = next;
}
}
});
}
static QueryTaskFuture evalRdeps(
final QueryEnvironment env,
VariableContext context,
final List args,
final Callback callback,
Optional> universeMaybe) {
final int depth = args.size() > 1 ? args.get(1).getInteger() : Integer.MAX_VALUE;
final Predicate universe = universeMaybe.isPresent()
? universeMaybe.get()
: Predicates.alwaysTrue();
if (env instanceof StreamableQueryEnvironment>) {
StreamableQueryEnvironment streamableEnv = ((StreamableQueryEnvironment) env);
return depth == Integer.MAX_VALUE && !universeMaybe.isPresent()
? streamableEnv.getAllRdepsUnboundedParallel(args.get(0).getExpression(), context, callback)
: streamableEnv.getAllRdeps(
args.get(0).getExpression(), universe, context, callback, depth);
} else {
return eval(env, args.get(0).getExpression(), universe, context, callback, depth);
}
}
}