*
 * Includes snapshots of any child element and the Merkle tree hash.
 */
public class DirectorySnapshot extends AbstractFileSystemLocationSnapshot {
    private final ChildMap<FileSystemLocationSnapshot> children;
    private final HashCode contentHash;

    public DirectorySnapshot(String absolutePath, String name, AccessType accessType, HashCode contentHash, List<FileSystemLocationSnapshot> children) {

        protected final T delegate;
        private final DirectorySnapshot directorySnapshot;

        public DirectoryVisitState(DirectorySnapshot unvisited, T delegate) {
            this.directorySnapshot = unvisited;
            this.delegate = delegate;
        }

        @Override
        public String getPath() {
            return directorySnapshot.getAbsolutePath();
        }

        @Override

     * when you already have a {@link DirectorySnapshot}.
     */
    default void enterDirectory(DirectorySnapshot directorySnapshot, EmptyDirectoryHandlingStrategy emptyDirectoryHandlingStrategy) {
        enterDirectory(directorySnapshot.getAccessType(), directorySnapshot.getAbsolutePath(), directorySnapshot.getName(), emptyDirectoryHandlingStrategy);
    }

    /**

    /**
     * Called after all entries in the directory has been visited.
     */
    public void leaveDirectory(DirectorySnapshot directorySnapshot, boolean isRoot) {}

    @Override
    public final void enterDirectory(DirectorySnapshot directorySnapshot) {
        enterDirectory(directorySnapshot, treeDepth == 0);
        treeDepth++;
    }

    @Override

public interface RelativePathTrackingFileSystemSnapshotHierarchyVisitor {
    /**
     * Called before visiting the contents of a directory.
     */
    default void enterDirectory(DirectorySnapshot directorySnapshot, RelativePathSupplier relativePath) {}

    /**
     * Called for each regular file/directory/missing/unavailable file.
     *
     * @return how to continue visiting the rest of the snapshot hierarchy.

            }

            @Override
            public void leaveDirectory(DirectorySnapshot directorySnapshot, boolean isRoot) {
                try {
                    writeEntryType(encoder, EntryType.DIR_CLOSE);
                    writeAccessType(encoder, directorySnapshot.getAccessType());
                    writeHashCode(encoder, directorySnapshot.getHash());
                } catch (IOException e) {

        private DirectorySnapshot currentRoot;

        public SnapshotFilteringVisitor(BiPredicate<FileSystemLocationSnapshot, Boolean> predicate) {
            this.predicate = predicate;
        }

        @Override
        public void enterDirectory(DirectorySnapshot directorySnapshot, boolean isRoot) {
            boolean isOutputDir = predicate.test(directorySnapshot, isRoot);

        def parentFile = sourceDir.createFile("parent.txt")
        def targetDir = testDirectory.file("target-directory")

        def directorySnapshot = new DirectorySnapshot(sourceDir.absolutePath, sourceDir.name, FileMetadata.AccessType.DIRECT, TestHashCodes.hashCodeFrom(1234), [
            new DirectorySnapshot(childDir.absolutePath, childDir.name, FileMetadata.AccessType.DIRECT, TestHashCodes.hashCodeFrom(2345), [

    @Override
    public void visitLeafElement(FileSystemLeafSnapshot snapshot) {
        delegate.visitLeafElement(snapshot);
    }

    @Override
    public void visitDirectory(DirectorySnapshot directorySnapshot) {
        delegate.visitDirectory(directorySnapshot);
    }

    public void markCurrentLevelAsFiltered() {
        isCurrentLevelUnfiltered.removeLast();
        isCurrentLevelUnfiltered.addLast(false);
    }

            this.builder = builder;
            this.hasBeenFiltered = hasBeenFiltered;
        }

        @Override
        public void enterDirectory(DirectorySnapshot directorySnapshot, RelativePathSupplier relativePath) {
            builder.enterDirectory(directorySnapshot, INCLUDE_EMPTY_DIRS);
        }

        @Override