Consolidate filesystem metadata operations in ActionFS by extending AbstractFileSystemWithCustomStat.

RELNOTES: None
PiperOrigin-RevId: 200071031

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

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionFileSystem.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionFileSystem.java
index 6fe598d..757c310 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionFileSystem.java
@@ -36,6 +36,7 @@
 import com.google.devtools.build.lib.profiler.Profiler;
 import com.google.devtools.build.lib.profiler.ProfilerTask;
 import com.google.devtools.build.lib.profiler.SilentCloseable;
+import com.google.devtools.build.lib.vfs.AbstractFileSystemWithCustomStat;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -51,7 +52,6 @@
 import java.io.OutputStream;
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
 /**
@@ -65,9 +65,9 @@
  *       access {@link env}, they must also used synchronized access.
  * </ul>
  */
-final class ActionFileSystem extends FileSystem implements MetadataProvider, InjectionListener {
-  private static final Logger LOGGER = Logger.getLogger(ActionFileSystem.class.getName());
-  public static final BaseEncoding LOWER_CASE_HEX = BaseEncoding.base16().lowerCase();
+final class ActionFileSystem extends AbstractFileSystemWithCustomStat
+    implements MetadataProvider, InjectionListener {
+  private static final BaseEncoding LOWER_CASE_HEX = BaseEncoding.base16().lowerCase();
 
   /** Actual underlying filesystem. */
   private final FileSystem delegate;
@@ -214,11 +214,14 @@
 
       @Override
       public boolean isDirectory() {
+        // TODO(felly): Support directory awareness.
         return false;
       }
 
       @Override
       public boolean isSymbolicLink() {
+        // TODO(felly): We should have minimal support for symlink awareness when looking at
+        // output --> src and src --> src symlinks.
         return false;
       }
 
@@ -306,37 +309,11 @@
   }
 
   @Override
-  protected boolean isSymbolicLink(Path path) {
-    // TODO(felly): We should have minimal support for symlink awareness when looking at
-    // output --> src and src --> src symlinks.
-    return false;
-  }
-
-  @Override
-  protected boolean isDirectory(Path path, boolean followSymlinks) {
-    // TODO(felly): Support directory awareness.
-    return true;
-  }
-
-  @Override
   protected Collection<String> getDirectoryEntries(Path path) throws IOException {
     // TODO(felly): Support directory traversal.
     return ImmutableList.of();
   }
 
-  @Override
-  protected boolean isFile(Path path, boolean followSymlinks) {
-    // TODO(felly): Unify is* methods with the stat() operation.
-    FileArtifactValue metadata = getMetadataUnchecked(path);
-    return metadata == null ? false : metadata.getType() == FileStateType.REGULAR_FILE;
-  }
-
-  @Override
-  protected boolean isSpecialFile(Path path, boolean followSymlinks) {
-    FileArtifactValue metadata = getMetadataUnchecked(path);
-    return metadata == null ? false : metadata.getType() == FileStateType.SPECIAL_FILE;
-  }
-
   private static String createSymbolicLinkErrorMessage(
       Path linkPath, PathFragment targetFragment, String message) {
     return "createSymbolicLink(" + linkPath + ", " + targetFragment + "): " + message;