| // Copyright 2023 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.skyframe.state; |
| |
| import com.google.devtools.build.skyframe.ErrorInfo; |
| import com.google.devtools.build.skyframe.EvaluationContext; |
| import com.google.devtools.build.skyframe.EvaluationResult; |
| import com.google.devtools.build.skyframe.MemoizingEvaluator; |
| import com.google.devtools.build.skyframe.SkyKey; |
| import com.google.devtools.build.skyframe.SkyValue; |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import javax.annotation.Nullable; |
| |
| /** |
| * Evaluates {@link StateMachine} using a given {@link MemoizingEvaluator} for testing. |
| * |
| * <p>As the {@link StateMachine} requests dependencies, delegates requests to the underlying graph |
| * and records missing values. Then evaluates any missing dependencies before resuming the {@link |
| * StateMachine}. |
| * |
| * <p>Only supports {@code keepGoing} evaluations. |
| */ |
| public final class StateMachineEvaluatorForTesting { |
| private final MemoizingEvaluator evaluator; |
| private final Driver driver; |
| |
| /** Values are either {@link SkyValue} or {@link Exception}. */ |
| private final HashMap<SkyKey, Object> previousResults = new HashMap<>(); |
| |
| /** |
| * Runs the given {@link StateMachine}. |
| * |
| * @return the result of the last evalution, if any, for error handling. |
| */ |
| @Nullable // Null if there were no evaluations. |
| public static EvaluationResult<SkyValue> run( |
| StateMachine root, MemoizingEvaluator evaluator, EvaluationContext context) |
| throws InterruptedException { |
| return new StateMachineEvaluatorForTesting(root, evaluator).evaluate(context); |
| } |
| |
| private StateMachineEvaluatorForTesting(StateMachine root, MemoizingEvaluator evaluator) { |
| this.driver = new Driver(root); |
| this.evaluator = evaluator; |
| } |
| |
| private EvaluationResult<SkyValue> evaluate(EvaluationContext context) |
| throws InterruptedException { |
| var missing = new ArrayList<SkyKey>(); |
| var env = |
| new EnvironmentForUtilities( |
| skyKey -> { |
| var value = previousResults.get(skyKey); |
| if (value != null) { |
| return value; |
| } |
| missing.add(skyKey); |
| return null; |
| }); |
| |
| EvaluationResult<SkyValue> result = null; |
| boolean hasError = false; |
| while (!driver.drive(env)) { |
| if (hasError) { |
| return result; // Exits if there was an error in the previous round. |
| } |
| |
| result = evaluator.evaluate(missing, context); |
| for (SkyKey key : missing) { |
| SkyValue value = result.get(key); |
| if (value != null) { |
| previousResults.put(key, value); |
| continue; |
| } |
| // Marks an error. The state machine will run one more time for "error bubbling" before |
| // exiting. |
| hasError = true; |
| ErrorInfo error = result.getError(key); |
| if (error == null) { |
| continue; |
| } |
| Exception exception = error.getException(); |
| if (exception != null) { |
| previousResults.put(key, exception); |
| } |
| // Otherwise, there might be a cycle. |
| } |
| missing.clear(); |
| } |
| return result; |
| } |
| } |