src/test/java/com/google/devtools/build/lib/unix/UnixFileSystemTest.java

// 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.unix;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.junit.Assert.assertThrows;

import com.google.common.util.concurrent.Uninterruptibles;
import com.google.devtools.build.lib.vfs.DigestHashFunction;
import com.google.devtools.build.lib.vfs.Dirent;
import com.google.devtools.build.lib.vfs.FileAccessException;
import com.google.devtools.build.lib.vfs.FileSystem;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.SymlinkAwareFileSystemTest;
import com.google.devtools.build.lib.vfs.Symlinks;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicReference;
import org.junit.Test;

/** Tests for the {@link com.google.devtools.build.lib.unix.UnixFileSystem} class. */
public class UnixFileSystemTest extends SymlinkAwareFileSystemTest {

  @Override
  protected FileSystem getFreshFileSystem(DigestHashFunction digestHashFunction) {
    return new UnixFileSystem(digestHashFunction, /*hashAttributeName=*/ "");
  }

  @Override
  public void destroyFileSystem(FileSystem fileSystem) {
    // Nothing.
  }

  // Most tests are just inherited from FileSystemTest.

  @Test
  public void testPermissions() throws Exception {
    Path file = absolutize("file");
    FileSystemUtils.createEmptyFile(file);
    for (int bits = 0; bits <= 0777; bits++) {
      String msg = "for permissions 0%s".formatted(Integer.toString(bits, 8));
      file.chmod(bits);
      assertWithMessage(msg).that(file.stat().getPermissions()).isEqualTo(bits);
      assertWithMessage(msg).that(file.isReadable()).isEqualTo((bits & 0400) != 0);
      assertWithMessage(msg).that(file.isWritable()).isEqualTo((bits & 0200) != 0);
      assertWithMessage(msg).that(file.isExecutable()).isEqualTo((bits & 0100) != 0);
    }
  }

  @Test
  public void testPermissionsError() throws Exception {
    Path file = absolutize("/");
    assertThrows(IOException.class, () -> file.chmod(0777));
  }

  @Test
  public void testCircularSymlinkFound() throws Exception {
    Path linkA = absolutize("link-a");
    Path linkB = absolutize("link-b");
    linkA.createSymbolicLink(linkB);
    linkB.createSymbolicLink(linkA);
    assertThat(linkA.exists(Symlinks.FOLLOW)).isFalse();
    assertThrows(IOException.class, () -> linkA.statIfFound(Symlinks.FOLLOW));
  }

  @Test
  public void testIsSpecialFile() throws Exception {
    Path regular = absolutize("regular");
    Path fifo = absolutize("fifo");
    FileSystemUtils.createEmptyFile(regular);
    NativePosixFiles.mkfifo(fifo.toString(), 0777);

    assertThat(regular.isFile()).isTrue();
    assertThat(regular.isSpecialFile()).isFalse();
    assertThat(regular.stat().isFile()).isTrue();
    assertThat(regular.stat().isSpecialFile()).isFalse();
    assertThat(fifo.isFile()).isTrue();
    assertThat(fifo.isSpecialFile()).isTrue();
    assertThat(fifo.stat().isFile()).isTrue();
    assertThat(fifo.stat().isSpecialFile()).isTrue();
  }

  @Test
  public void testReaddirSpecialFile() throws Exception {
    Path dir = absolutize("dir");
    Path symlink = dir.getChild("symlink");
    Path fifo = dir.getChild("fifo");
    dir.createDirectoryAndParents();
    symlink.createSymbolicLink(fifo.asFragment());
    NativePosixFiles.mkfifo(fifo.toString(), 0777);

    assertThat(dir.getDirectoryEntries()).containsExactly(symlink, fifo);

    assertThat(dir.readdir(Symlinks.NOFOLLOW))
        .containsExactly(
            new Dirent("symlink", Dirent.Type.SYMLINK), new Dirent("fifo", Dirent.Type.UNKNOWN));

    assertThat(dir.readdir(Symlinks.FOLLOW))
        .containsExactly(
            new Dirent("symlink", Dirent.Type.UNKNOWN), new Dirent("fifo", Dirent.Type.UNKNOWN));
  }

  @Test
  public void testReaddirPermissionError() throws Exception {
    Path dir = absolutize("dir");
    dir.createDirectoryAndParents();
    dir.chmod(0333); // unreadable

    assertThrows(FileAccessException.class, dir::getDirectoryEntries);
    assertThrows(FileAccessException.class, () -> dir.readdir(Symlinks.NOFOLLOW));
  }

  @Test
  public void testTransferToWorksWhenCallingThreadHasInterruptBitSet() throws Throwable {
    Path src = absolutize("src");
    Path dst = absolutize("dst");

    FileSystemUtils.writeContent(src, UTF_8, "hello world");

    CountDownLatch ready = new CountDownLatch(1);
    AtomicReference<Throwable> caughtException = new AtomicReference<>();
    Thread thread =
        new Thread(
            () -> {
              try (InputStream in = src.getInputStream();
                  OutputStream out = dst.getOutputStream()) {
                Uninterruptibles.awaitUninterruptibly(ready);
                assertThat(Thread.currentThread().isInterrupted()).isTrue();
                in.transferTo(out);
                assertThat(Thread.currentThread().isInterrupted()).isTrue();
                assertThat(((FileInputStream) in).getChannel().isOpen()).isTrue();
                assertThat(((FileOutputStream) out).getChannel().isOpen()).isTrue();
              } catch (Throwable e) {
                caughtException.set(e);
              }
            });

    thread.start();
    thread.interrupt();
    ready.countDown();
    thread.join();

    if (caughtException.get() != null) {
      throw caughtException.get();
    }
    assertThat(dst.exists()).isTrue();
    assertThat(FileSystemUtils.readContent(dst, UTF_8)).isEqualTo("hello world");
  }

  @Test
  public void testInputStreamIsFileInputStream() throws Exception {
    try (InputStream in = xFile.getInputStream()) {
      assertThat(in).isInstanceOf(FileInputStream.class);
    }
  }

  @Test
  public void testOutputStreamIsFileOutputStream() throws Exception {
    try (OutputStream out = xFile.getOutputStream()) {
      assertThat(out).isInstanceOf(FileOutputStream.class);
    }
  }
}