| // 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.android.junctions; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.nio.file.Path; |
| import javax.annotation.Nullable; |
| |
| /** |
| * Interface to create junctions (directory symlinks). |
| * |
| * <p>Junctions are directory symlinks on NTFS filesystems. They are useful on Windows, because |
| * creating them doesn't require any privileges, as opposed to the creation of file symlinks which |
| * does. |
| * |
| * <p>On Windows, Bazel and the Android BusyBox uses junctions to work around path length |
| * limitations of the Windows Shell and of tools like aapt.exe and the PNG cruncher. The limit is |
| * 260 characters for all paths. The filesystem supports longer paths than that, but the tools |
| * usually don't. To work around that limitation, we create junctions that have short paths but |
| * point to long paths (this is allowed). |
| * |
| * <p>On Linux/MacOS the junction creator may have a no-op implementation. |
| */ |
| public interface JunctionCreator extends Closeable { |
| /** |
| * Returns an equivalent path to `target`, which may or may not be the same as `target`. |
| * |
| * <p>Depending on the implementation, this method may return `target` itself, or may create a |
| * junction that points to `target` (if `target` is a directory) or the parent of it (if `target` |
| * is a file). |
| */ |
| @Nullable |
| public abstract Path create(@Nullable Path target) throws IOException; |
| } |