| // 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.actions.cache; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.devtools.build.lib.actions.ActionInput; |
| import com.google.devtools.build.lib.vfs.PathFragment; |
| import com.google.protobuf.ByteString; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * An ActionInput that does not actually exist on the filesystem, but can still be written to an |
| * OutputStream. |
| */ |
| public interface VirtualActionInput extends ActionInput { |
| /** |
| * Writes the fake file to an OutputStream. MUST be deterministic, in that multiple calls to write |
| * the same VirtualActionInput must write identical bytes. |
| */ |
| void writeTo(OutputStream out) throws IOException; |
| |
| /** |
| * Gets a {@link ByteString} representation of the fake file. Used to avoid copying if the fake |
| * file is internally represented as a {@link ByteString}. |
| */ |
| ByteString getBytes() throws IOException; |
| |
| /** |
| * Returns the Metadata for this input if available. Null otherwise. |
| * |
| * @throws IOException |
| */ |
| default Metadata getMetadata() throws IOException { |
| return null; |
| } |
| |
| /** |
| * In some cases, we want empty files in the runfiles tree that have no corresponding artifact. We |
| * use instances of this class to represent those files. |
| */ |
| public final class EmptyActionInput implements VirtualActionInput { |
| private final PathFragment execPath; |
| |
| public EmptyActionInput(PathFragment execPath) { |
| this.execPath = Preconditions.checkNotNull(execPath); |
| } |
| |
| public EmptyActionInput(String execPath) { |
| this(PathFragment.create(execPath)); |
| } |
| |
| @Override |
| public String getExecPathString() { |
| return execPath.getPathString(); |
| } |
| |
| @Override |
| public PathFragment getExecPath() { |
| return execPath; |
| } |
| |
| @Override |
| public void writeTo(OutputStream out) throws IOException { |
| // Write no content - it's an empty file. |
| } |
| |
| @Override |
| public ByteString getBytes() throws IOException { |
| return ByteString.EMPTY; |
| } |
| |
| @Override |
| public String toString() { |
| return "EmptyActionInput: " + execPath; |
| } |
| } |
| } |