func (fs *helloFS) ReadDir(
	op *fuseops.ReadDirOp) (err error) {
	// Find the info for this inode.
	info, ok := gInodeInfo[op.Inode]
	if !ok {
		err = fuse.ENOENT
		return
	}

	if !info.dir {
		err = fuse.EIO
		return
	}

	entries := info.children

	// Grab the range of interest.
	if op.Offset > fuseops.DirOffset(len(entries)) {
		err = fuse.EIO
		return
	}

	entries = entries[op.Offset:]

	// Resume at the specified offset into the array.
	for _, e := range entries {
		op.Data = fuseutil.AppendDirent(op.Data, e)
		if len(op.Data) > op.Size {
			op.Data = op.Data[:op.Size]
			break
		}
	}

	return
}

// ReadDir reads entries in a specific directory.
//
// Required for fuse.FileSystem.
func (k *KodingNetworkFS) ReadDir(ctx context.Context, op *fuseops.ReadDirOp) error {
	dir, err := k.getDir(ctx, op.Inode)
	if err != nil {
		return err
	}

	entries, err := dir.ReadEntries(op.Offset)
	if err != nil {
		return err
	}

	var bytesRead int
	for _, e := range entries {
		c := fuseutil.WriteDirent(op.Dst[bytesRead:], *e)
		if c == 0 {
			break
		}

		bytesRead += c
	}

	op.BytesRead = bytesRead

	return nil
}

func (fs *flushFS) ReadDir(
	op *fuseops.ReadDirOp) (err error) {
	fs.mu.Lock()
	defer fs.mu.Unlock()

	// Create the appropriate listing.
	var dirents []fuseutil.Dirent

	switch op.Inode {
	case fuseops.RootInodeID:
		dirents = []fuseutil.Dirent{
			fuseutil.Dirent{
				Offset: 1,
				Inode:  fooID,
				Name:   "foo",
				Type:   fuseutil.DT_File,
			},

			fuseutil.Dirent{
				Offset: 2,
				Inode:  barID,
				Name:   "bar",
				Type:   fuseutil.DT_Directory,
			},
		}

	case barID:

	default:
		err = fmt.Errorf("Unexpected inode: %v", op.Inode)
		return
	}

	// If the offset is for the end of the listing, we're done. Otherwise we
	// expect it to be for the start.
	switch op.Offset {
	case fuseops.DirOffset(len(dirents)):
		return

	case 0:

	default:
		err = fmt.Errorf("Unexpected offset: %v", op.Offset)
		return
	}

	// Fill in the listing.
	for _, de := range dirents {
		op.Data = fuseutil.AppendDirent(op.Data, de)
	}

	// We don't support doing this in anything more than one shot.
	if len(op.Data) > op.Size {
		err = fmt.Errorf("Couldn't fit listing in %v bytes", op.Size)
		return
	}

	return
}

func (fs *memFS) ReadDir(
	op *fuseops.ReadDirOp) (err error) {
	fs.mu.Lock()
	defer fs.mu.Unlock()

	// Grab the directory.
	inode := fs.getInodeOrDie(op.Inode)

	// Serve the request.
	op.Data = inode.ReadDir(int(op.Offset), op.Size)

	return
}

// Handle a request to read from the directory, without responding.
//
// Special case: we assume that a zero offset indicates that rewinddir has been
// called (since fuse gives us no way to intercept and know for sure), and
// start the listing process over again.
//
// LOCKS_REQUIRED(dh.Mu)
// LOCKS_EXCLUDED(du.in)
func (dh *dirHandle) ReadDir(
	op *fuseops.ReadDirOp) (err error) {
	// If the request is for offset zero, we assume that either this is the first
	// call or rewinddir has been called. Reset state.
	if op.Offset == 0 {
		dh.entries = nil
		dh.entriesValid = false
	}

	// Do we need to read entries from GCS?
	if !dh.entriesValid {
		err = dh.ensureEntries(op.Context())
		if err != nil {
			return
		}
	}

	// Is the offset past the end of what we have buffered? If so, this must be
	// an invalid seekdir according to posix.
	index := int(op.Offset)
	if index > len(dh.entries) {
		err = fuse.EINVAL
		return
	}

	// We copy out entries until we run out of entries or space.
	for i := index; i < len(dh.entries); i++ {
		op.Data = fuseutil.AppendDirent(op.Data, dh.entries[i])
		if len(op.Data) > op.Size {
			op.Data = op.Data[:op.Size]
			break
		}
	}

	return
}

// LOCKS_EXCLUDED(fs.mu)
func (fs *Goofys) ReadDir(
	ctx context.Context,
	op *fuseops.ReadDirOp) (err error) {

	// Find the handle.
	fs.mu.Lock()
	dh := fs.dirHandles[op.Handle]
	//inode := fs.inodes[op.Inode]
	fs.mu.Unlock()

	if dh == nil {
		panic(fmt.Sprintf("can't find dh=%v", op.Handle))
	}

	dh.inode.logFuse("ReadDir", op.Offset)

	dh.mu.Lock()
	defer dh.mu.Unlock()

	for i := op.Offset; ; i++ {
		e, err := dh.ReadDir(fs, i)
		if err != nil {
			return err
		}
		if e == nil {
			break
		}

		n := fuseutil.WriteDirent(op.Dst[op.BytesRead:], *e)
		if n == 0 {
			break
		}

		dh.inode.logFuse("<-- ReadDir", e.Name, e.Offset)

		op.BytesRead += n
	}

	return
}

func (fs *helloFS) ReadDir(
	ctx context.Context,
	op *fuseops.ReadDirOp) (err error) {
	// Find the info for this inode.
	info, ok := gInodeInfo[op.Inode]
	if !ok {
		err = fuse.ENOENT
		return
	}

	if !info.dir {
		err = fuse.EIO
		return
	}

	entries := info.children

	// Grab the range of interest.
	if op.Offset > fuseops.DirOffset(len(entries)) {
		err = fuse.EIO
		return
	}

	entries = entries[op.Offset:]

	// Resume at the specified offset into the array.
	for _, e := range entries {
		n := fuseutil.WriteDirent(op.Dst[op.BytesRead:], e)
		if n == 0 {
			break
		}

		op.BytesRead += n
	}

	return
}