1 files changed, 72 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/DirectoryListingFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/DirectoryListingFunction.java
new file mode 100644
index 0000000000..93c3d752bf
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/DirectoryListingFunction.java
@@ -0,0 +1,72 @@
+// Copyright 2014 Google Inc. 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 javax.annotation.Nullable;
+
+/**
+ * A {@link SkyFunction} for {@link DirectoryListingValue}s.
+ */
+final class DirectoryListingFunction implements SkyFunction {
+
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env)
+      throws DirectoryListingFunctionException {
+    RootedPath dirRootedPath = (RootedPath) skyKey.argument();
+
+    FileValue dirFileValue = (FileValue) env.getValue(FileValue.key(dirRootedPath));
+    if (dirFileValue == null) {
+      return null;
+    }
+
+    RootedPath realDirRootedPath = dirFileValue.realRootedPath();
+    if (!dirFileValue.isDirectory()) {
+      // Recall that the directory is assumed to exist (see DirectoryListingValue#key).
+      throw new DirectoryListingFunctionException(new InconsistentFilesystemException(
+          dirRootedPath.asPath() + " is no longer an existing directory. Did you delete it during "
+              + "the build?"));
+    }
+
+    DirectoryListingStateValue directoryListingStateValue =
+       (DirectoryListingStateValue) env.getValue(DirectoryListingStateValue.key(
+           realDirRootedPath));
+    if (directoryListingStateValue == null) {
+      return null;
+    }
+
+    return DirectoryListingValue.value(dirRootedPath, dirFileValue, directoryListingStateValue);
+  }
+
+  @Nullable
+  @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 DirectoryListingFunction#compute}.
+   */
+  private static final class DirectoryListingFunctionException extends SkyFunctionException {
+    public DirectoryListingFunctionException(InconsistentFilesystemException e) {
+      super(e, Transience.TRANSIENT);
+    }
+  }
+}