src/main/java/com/google/devtools/build/lib/skyframe/DirectoryListingStateFunction.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72

// 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.skyframe;

import com.google.devtools.build.lib.vfs.RootedPath;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunctionException;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.SkyValue;
import java.io.IOException;

/**
 * A {@link SkyFunction} for {@link DirectoryListingStateValue}s.
 *
 * <p>Merely calls DirectoryListingStateValue#create, but also has special handling for
 * directories outside the package roots (see {@link ExternalFilesHelper}).
 */
public class DirectoryListingStateFunction implements SkyFunction {

  private final ExternalFilesHelper externalFilesHelper;

  public DirectoryListingStateFunction(ExternalFilesHelper externalFilesHelper) {
    this.externalFilesHelper = externalFilesHelper;
  }

  @Override
  public SkyValue compute(SkyKey skyKey, Environment env)
      throws DirectoryListingStateFunctionException, InterruptedException {
    RootedPath dirRootedPath = (RootedPath) skyKey.argument();

    try {
      externalFilesHelper.maybeHandleExternalFile(dirRootedPath, env);
      if (env.valuesMissing()) {
        return null;
      }
      return DirectoryListingStateValue.create(dirRootedPath);
    } catch (ExternalFilesHelper.NonexistentImmutableExternalFileException e) {
      // DirectoryListingStateValue.key assumes the path exists. This exception here is therefore
      // indicative of a programming bug.
      throw new IllegalStateException(dirRootedPath.toString(), e);
    } catch (IOException e) {
      throw new DirectoryListingStateFunctionException(e);
    }
  }

  @Override
  public String extractTag(SkyKey skyKey) {
    return null;
  }

  /**
   * Used to declare all the exception types that can be wrapped in the exception thrown by
   * {@link DirectoryListingStateFunction#compute}.
   */
  private static final class DirectoryListingStateFunctionException
      extends SkyFunctionException {
    public DirectoryListingStateFunctionException(IOException e) {
      super(e, Transience.TRANSIENT);
    }
  }
}