| // 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.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.EvaluateExpression; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryTaskFuture; |
| import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ThreadSafeMutableSet; |
| import com.google.devtools.build.lib.server.FailureDetails.Query; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.concurrent.CancellationException; |
| |
| /** |
| * A some(x) filter expression, which returns certain number of arbitrary nodes in set x, or fails |
| * if x is empty. An optional integer-literal second argument may be specified; it specifies number |
| * of arbitrary nodes to be returned. If second argument is empty, return one node. |
| * |
| * <pre>expr ::= SOME '(' expr ')'</pre> |
| * |
| * <pre> | SOME '(' expr ',' count ')'</pre> |
| */ |
| class SomeFunction implements QueryFunction { |
| SomeFunction() {} |
| |
| @Override |
| public String getName() { |
| return "some"; |
| } |
| |
| @Override |
| public int getMandatoryArguments() { |
| return 1; // last argument is optional |
| } |
| |
| @Override |
| public List<ArgumentType> getArgumentTypes() { |
| return ImmutableList.of(ArgumentType.EXPRESSION, ArgumentType.INTEGER); |
| } |
| |
| @Override |
| public <T> QueryTaskFuture<Void> eval( |
| QueryEnvironment<T> env, |
| QueryExpressionContext<T> context, |
| final QueryExpression expression, |
| List<Argument> args, |
| final Callback<T> callback) { |
| |
| // Add a second optional integer parameter indicating return size. |
| final int resultMaxSize = args.size() > 1 ? args.get(1).getInteger() : 1; |
| |
| // Since the callback will be executed multiple times, so we need to avoid some target |
| // being added multiple times in different callback execution. So we need to have a state |
| // variable (`targetsSet` below) to track which ones are already added in order to avoid adding |
| // duplicates. |
| ThreadSafeMutableSet<T> targetsSet = env.createThreadSafeMutableSet(); |
| |
| EvaluateExpression<T> evaluateExpression = |
| env.createEvaluateExpression(args.get(0).getExpression(), context); |
| QueryTaskFuture<Void> queryTaskFuture = |
| evaluateExpression.eval( |
| partialResult -> { |
| if (Iterables.isEmpty(partialResult)) { |
| return; |
| } |
| |
| boolean shouldCancel = false; |
| synchronized (targetsSet) { |
| ArrayList<T> current = new ArrayList<>(); |
| for (T nextTarget : partialResult) { |
| if (targetsSet.size() >= resultMaxSize) { |
| break; |
| } |
| if (targetsSet.add(nextTarget)) { |
| current.add(nextTarget); |
| } |
| } |
| |
| if (!current.isEmpty()) { |
| callback.process(current); |
| } |
| |
| if (targetsSet.size() >= resultMaxSize) { |
| shouldCancel = true; |
| } |
| } |
| |
| if (shouldCancel) { |
| var unused = evaluateExpression.gracefullyCancel(); |
| } |
| }); |
| |
| return env.whenSucceedsOrIsCancelledCall( |
| queryTaskFuture, |
| () -> { |
| if (evaluateExpression.isUngracefullyCancelled()) { |
| throw new CancellationException(); |
| } |
| |
| if (targetsSet.isEmpty()) { |
| throw new QueryException( |
| expression, "argument set is empty", Query.Code.ARGUMENTS_MISSING); |
| } |
| return null; |
| }); |
| } |
| } |