| // Copyright 2019 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.actions; |
| |
| import com.google.devtools.build.lib.util.Fingerprint; |
| import javax.annotation.Nullable; |
| |
| /** |
| * An implementation of {@link ActionAnalysisMetadata} that caches its {@linkplain #getKey key} so |
| * that it is only computed once. |
| */ |
| public abstract class ActionKeyCacher implements ActionAnalysisMetadata { |
| |
| @Nullable private volatile String cachedKey = null; |
| |
| @Override |
| public final String getKey(ActionKeyContext actionKeyContext) { |
| if (cachedKey == null) { |
| synchronized (this) { |
| if (cachedKey == null) { |
| try { |
| Fingerprint fp = new Fingerprint(); |
| computeKey(actionKeyContext, fp); |
| |
| // Add a bool indicating whether the execution platform was set. |
| fp.addBoolean(getExecutionPlatform() != null); |
| if (getExecutionPlatform() != null) { |
| // Add the execution platform information. |
| getExecutionPlatform().addTo(fp); |
| } |
| |
| fp.addStringMap(getExecProperties()); |
| |
| // Compute the actual key and store it. |
| cachedKey = fp.hexDigestAndReset(); |
| } catch (CommandLineExpansionException e) { |
| cachedKey = KEY_ERROR; |
| } |
| } |
| } |
| } |
| return cachedKey; |
| } |
| |
| /** |
| * See the javadoc for {@link Action} and {@link ActionAnalysisMetadata#getKey} for the contract |
| * of this method. |
| */ |
| protected abstract void computeKey(ActionKeyContext actionKeyContext, Fingerprint fp) |
| throws CommandLineExpansionException; |
| } |