| // 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.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.QueryTaskCallable; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskFuture; |
| import java.util.List; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| /** |
| * A some(x) filter expression, which returns an arbitrary node in set x, or |
| * fails if x is empty. |
| * |
| * <pre>expr ::= SOME '(' expr ')'</pre> |
| */ |
| class SomeFunction implements QueryFunction { |
| SomeFunction() { |
| } |
| |
| @Override |
| public String getName() { |
| return "some"; |
| } |
| |
| @Override |
| public int getMandatoryArguments() { |
| return 1; |
| } |
| |
| @Override |
| public List<ArgumentType> getArgumentTypes() { |
| return ImmutableList.of(ArgumentType.EXPRESSION); |
| } |
| |
| @Override |
| public <T> QueryTaskFuture<Void> eval( |
| QueryEnvironment<T> env, |
| QueryExpressionContext<T> context, |
| final QueryExpression expression, |
| List<Argument> args, |
| final Callback<T> callback) { |
| final AtomicBoolean someFound = new AtomicBoolean(false); |
| QueryTaskFuture<Void> operandEvalFuture = env.eval( |
| args.get(0).getExpression(), |
| context, |
| new Callback<T>() { |
| @Override |
| public void process(Iterable<T> partialResult) |
| throws QueryException, InterruptedException { |
| if (Iterables.isEmpty(partialResult) || !someFound.compareAndSet(false, true)) { |
| return; |
| } |
| callback.process(ImmutableSet.of(partialResult.iterator().next())); |
| } |
| }); |
| return env.whenSucceedsCall( |
| operandEvalFuture, |
| new QueryTaskCallable<Void>() { |
| @Override |
| public Void call() throws QueryException { |
| if (!someFound.get()) { |
| throw new QueryException(expression, "argument set is empty"); |
| } |
| return null; |
| } |
| }); |
| } |
| } |