src/main/java/com/google/devtools/build/lib/testing/vfs/SpiedFileSystem.java

// Copyright 2022 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
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package com.google.devtools.build.lib.testing.vfs;

import static org.mockito.Mockito.spy;

import com.google.devtools.build.lib.vfs.DelegateFileSystem;
import com.google.devtools.build.lib.vfs.DigestHashFunction;
import com.google.devtools.build.lib.vfs.FileSystem;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Delegate file system with the sole purpose of creating a {@link org.mockito.Mockito#spy}.
 *
 * <p>This class purposely makes the {@link FileSystem} methods public so that tests can mock those.
 * Please feel free to add any methods you need.
 */
public class SpiedFileSystem extends DelegateFileSystem {

  private SpiedFileSystem(FileSystem delegateFs) {
    super(delegateFs);
  }

  /**
   * Create a spied file system instance delegating all calls to the provided {@code fileSystem}.
   */
  public static SpiedFileSystem createSpy(FileSystem fileSystem) {
    return spy(new SpiedFileSystem(fileSystem));
  }

  public static SpiedFileSystem createInMemorySpy() {
    return createSpy(new InMemoryFileSystem(DigestHashFunction.SHA256));
  }

  @Override
  public OutputStream getOutputStream(PathFragment path, boolean append) throws IOException {
    return super.getOutputStream(path, append);
  }

  @Override
  public boolean createWritableDirectory(PathFragment path) throws IOException {
    return super.createWritableDirectory(path);
  }
}