| // Copyright 2017 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.concurrent.ThreadSafety.ThreadSafe; |
| import java.io.IOException; |
| import javax.annotation.Nullable; |
| |
| /** Provides {@link ActionInput} metadata. */ |
| @ThreadSafe |
| public interface MetadataProvider { |
| |
| /** |
| * Returns a {@link FileArtifactValue} for the given {@link ActionInput}. |
| * |
| * <p>If the given input is an output {@link Artifact} of an action, then the returned value is |
| * current as of the action's most recent execution time (which may be from a prior build, in |
| * which case the value may or may not be up to date for the current build). The returned value |
| * can vary across calls, for example if the action executes between calls and produces different |
| * outputs than its previous execution. |
| * |
| * <p>The returned {@link FileArtifactValue} instance corresponds to the final target of a symlink |
| * and therefore must not have a type of {@link FileStateType#SYMLINK}. |
| * |
| * @param input the input to retrieve the digest for |
| * @return the artifact's digest or null if digest cannot be obtained (due to artifact |
| * non-existence, lookup errors, or any other reason) |
| * @throws IOException if the input cannot be digested |
| */ |
| @Nullable |
| FileArtifactValue getMetadata(ActionInput input) throws IOException; |
| |
| /** Looks up an input from its exec path. */ |
| @Nullable |
| ActionInput getInput(String execPath); |
| } |