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// 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;
import com.google.common.base.Preconditions;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collection;
/**
* 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(Path path, boolean followSymlinks) throws IOException {
* if (!someCondition) {
* return super.getFileSize(path, followSymlinks);
* }
* return rpc.getFileSize(path, followSymlinks);
* }
* </code>
*/
public abstract class DelegateFileSystem extends FileSystem {
private final FileSystem delegateFs;
public DelegateFileSystem(FileSystem delegateFs) {
super(Preconditions.checkNotNull(delegateFs, "delegateFs").getDigestFunction());
this.delegateFs = delegateFs;
}
@Override
public boolean supportsModifications(Path path) {
return delegateFs.supportsModifications(toDelegatePath(path));
}
@Override
public boolean supportsSymbolicLinksNatively(Path path) {
return delegateFs.supportsSymbolicLinksNatively(toDelegatePath(path));
}
@Override
protected boolean supportsHardLinksNatively(Path path) {
return delegateFs.supportsHardLinksNatively(toDelegatePath(path));
}
@Override
public boolean isFilePathCaseSensitive() {
return delegateFs.isFilePathCaseSensitive();
}
@Override
public boolean createDirectory(Path path) throws IOException {
return delegateFs.createDirectory(toDelegatePath(path));
}
@Override
public void createDirectoryAndParents(Path path) throws IOException {
delegateFs.createDirectoryAndParents(toDelegatePath(path));
}
@Override
protected long getFileSize(Path path, boolean followSymlinks) throws IOException {
return delegateFs.getFileSize(toDelegatePath(path), followSymlinks);
}
@Override
public boolean delete(Path path) throws IOException {
return delegateFs.delete(toDelegatePath(path));
}
@Override
protected long getLastModifiedTime(Path path, boolean followSymlinks) throws IOException {
return delegateFs.getLastModifiedTime(toDelegatePath(path), followSymlinks);
}
@Override
public void setLastModifiedTime(Path path, long newTime) throws IOException {
delegateFs.setLastModifiedTime(toDelegatePath(path), newTime);
}
@Override
protected boolean isSymbolicLink(Path path) {
return delegateFs.isSymbolicLink(toDelegatePath(path));
}
@Override
protected boolean isDirectory(Path path, boolean followSymlinks) {
return delegateFs.isDirectory(toDelegatePath(path), followSymlinks);
}
@Override
protected boolean isFile(Path path, boolean followSymlinks) {
return delegateFs.isFile(toDelegatePath(path), followSymlinks);
}
@Override
protected boolean isSpecialFile(Path path, boolean followSymlinks) {
return delegateFs.isSpecialFile(toDelegatePath(path), followSymlinks);
}
@Override
protected void createSymbolicLink(Path linkPath, PathFragment targetFragment) throws IOException {
delegateFs.createSymbolicLink(toDelegatePath(linkPath), targetFragment);
}
@Override
protected PathFragment readSymbolicLink(Path path) throws IOException {
return delegateFs.readSymbolicLink(toDelegatePath(path));
}
@Override
protected boolean exists(Path path, boolean followSymlinks) {
return delegateFs.exists(toDelegatePath(path), followSymlinks);
}
@Override
public boolean exists(Path path) {
return delegateFs.exists(toDelegatePath(path));
}
@Override
protected Collection<String> getDirectoryEntries(Path path) throws IOException {
return delegateFs.getDirectoryEntries(toDelegatePath(path));
}
@Override
protected boolean isReadable(Path path) throws IOException {
return delegateFs.isReadable(toDelegatePath(path));
}
@Override
protected void setReadable(Path path, boolean readable) throws IOException {
delegateFs.setReadable(toDelegatePath(path), readable);
}
@Override
protected boolean isWritable(Path path) throws IOException {
return delegateFs.isWritable(toDelegatePath(path));
}
@Override
public void setWritable(Path path, boolean writable) throws IOException {
delegateFs.setWritable(toDelegatePath(path), writable);
}
@Override
protected boolean isExecutable(Path path) throws IOException {
return delegateFs.isExecutable(toDelegatePath(path));
}
@Override
protected void setExecutable(Path path, boolean executable) throws IOException {
delegateFs.setExecutable(toDelegatePath(path), executable);
}
@Override
protected InputStream getInputStream(Path path) throws IOException {
return delegateFs.getInputStream(toDelegatePath(path));
}
@Override
protected OutputStream getOutputStream(Path path, boolean append) throws IOException {
return delegateFs.getOutputStream(toDelegatePath(path), append);
}
@Override
public void renameTo(Path sourcePath, Path targetPath) throws IOException {
delegateFs.renameTo(toDelegatePath(sourcePath), toDelegatePath(targetPath));
}
@Override
protected void createFSDependentHardLink(Path linkPath, Path originalPath) throws IOException {
delegateFs.createFSDependentHardLink(toDelegatePath(linkPath), toDelegatePath(originalPath));
}
@Override
public String getFileSystemType(Path path) {
return delegateFs.getFileSystemType(toDelegatePath(path));
}
@Override
public void deleteTree(Path path) throws IOException {
delegateFs.deleteTree(toDelegatePath(path));
}
@Override
public void deleteTreesBelow(Path dir) throws IOException {
delegateFs.deleteTreesBelow(toDelegatePath(dir));
}
@Override
public byte[] getxattr(Path path, String name, boolean followSymlinks) throws IOException {
return delegateFs.getxattr(toDelegatePath(path), name, followSymlinks);
}
@Override
protected byte[] getFastDigest(Path path) throws IOException {
return delegateFs.getFastDigest(toDelegatePath(path));
}
@Override
protected byte[] getDigest(Path path) throws IOException {
return delegateFs.getDigest(toDelegatePath(path));
}
@Override
protected PathFragment resolveOneLink(Path path) throws IOException {
return delegateFs.resolveOneLink(toDelegatePath(path));
}
@Override
protected Path resolveSymbolicLinks(Path path) throws IOException {
return fromDelegatePath(delegateFs.resolveSymbolicLinks(toDelegatePath(path)));
}
@Override
protected FileStatus stat(Path path, boolean followSymlinks) throws IOException {
return delegateFs.stat(toDelegatePath(path), followSymlinks);
}
@Override
protected FileStatus statNullable(Path path, boolean followSymlinks) {
return delegateFs.statNullable(toDelegatePath(path), followSymlinks);
}
@Override
protected FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
return delegateFs.statIfFound(toDelegatePath(path), followSymlinks);
}
@Override
protected PathFragment readSymbolicLinkUnchecked(Path path) throws IOException {
return delegateFs.readSymbolicLink(toDelegatePath(path));
}
@Override
protected Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
return delegateFs.readdir(toDelegatePath(path), followSymlinks);
}
@Override
protected void chmod(Path path, int mode) throws IOException {
delegateFs.chmod(toDelegatePath(path), mode);
}
@Override
protected void createHardLink(Path linkPath, Path originalPath) throws IOException {
delegateFs.createHardLink(toDelegatePath(linkPath), toDelegatePath(originalPath));
}
@Override
protected void prefetchPackageAsync(Path path, int maxDirs) {
delegateFs.prefetchPackageAsync(toDelegatePath(path), maxDirs);
}
protected final Path toDelegatePath(Path path) {
Preconditions.checkArgument(path.getFileSystem() == this);
return Path.create(path.getPathString(), delegateFs);
}
protected final Path fromDelegatePath(Path delegatePath) {
Preconditions.checkArgument(delegatePath.getFileSystem() == delegateFs);
return Path.create(delegatePath.getPathString(), this);
}
}