| // 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.vfs; |
| |
| /** |
| * A file system that delegates all operations to {@code delegateFs} under the hood. |
| * |
| * <p>This is helpful when wanting to implement a file system on top of another file system as it |
| * allows code patterns like: <code> |
| * {@literal @}Override |
| * protected long getFileSize(PathFragment path, boolean followSymlinks) throws IOException { |
| * if (!someCondition) { |
| * return super.getFileSize(path, followSymlinks); |
| * } |
| * return rpc.getFileSize(path, followSymlinks); |
| * } |
| * </code> |
| * |
| * <p>The implementation uses {@link PathTransformingDelegateFileSystem} with identity path |
| * transformations ({@linkplain PathTransformingDelegateFileSystem#toDelegatePath(PathFragment) |
| * toDelegatePath} and {@linkplain PathTransformingDelegateFileSystem#fromDelegatePath(PathFragment) |
| * fromDelegatePath}). |
| */ |
| public abstract class DelegateFileSystem extends PathTransformingDelegateFileSystem { |
| |
| public DelegateFileSystem(FileSystem delegateFs) { |
| super(delegateFs); |
| } |
| |
| @Override |
| protected final PathFragment toDelegatePath(PathFragment path) { |
| return path; |
| } |
| |
| @Override |
| protected final PathFragment fromDelegatePath(PathFragment delegatePath) { |
| return delegatePath; |
| } |
| } |