You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mbox.go
    path of file: ./repos/inbucket/pkg/storage/file
    
    the code of the file until where you have to start completion: package file

import (
	"bufio"
	"encoding/gob"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sync"

	"github.com/inbucket/inbucket/v3/pkg/message"
	"github.com/inbucket/inbucket/v3/pkg/storage"
	"github.com/rs/zerolog/log"
)

// mbox manages the mail for a specific user and correlates to a particular directory on disk.
// mbox methods are not thread safe, mbox.RWMutex must be held prior to calling.
type mbox struct {
	*sync.RWMutex
	store       *Store
	name        string
	dirName     string
	path        string
	indexLoaded bool
	indexPath   string
	messages    []*Message
}

// getMessages scans the mailbox directory for .gob files and decodes them into
// a slice of Message objects.
func (mb *mbox) getMessages() ([]storage.Message, error) {
	if !mb.indexLoaded {
		if err := mb.readIndex(); err != nil {
			return nil, err
		}
	}
	messages := make([]storage.Message, len(mb.messages))
	for i, m := range mb.messages {
		messages[i] = m
	}
	return messages, nil
}

// getMessage decodes a single message by ID and returns a Message object.
func (mb *mbox) getMessage(id string) (storage.Message, error) {
	if !mb.indexLoaded {
		if err := mb.readIndex(); err != nil {
			return nil, err
		}
	}
	if i
    
func (mb *mbox) readIndex() error {
	// Clear message slice, open index
	mb.messages = mb.messages[:0]
	// Check if index exists
	if _, err := os.Stat(mb.indexPath); err != nil {
		// Does not exist, but that's not an error in our world
		log.Debug().Str("module", "storage").Str("path", mb.indexPath).
			Msg("Index does not yet exist")
		mb.indexLoaded = true

		//lint:ignore nilerr missing mailboxes are considered empty.
		return nil
	}
	file, err := os.Open(mb.indexPath)
	if err != nil {
		return err
	}
	defer func() {
		if err := file.Close(); err != nil {
			log.Error().Str("module", "storage").Str("path", mb.indexPath).Err(err).
				Msg("Failed to close")
		}
	}()
	// Decode gob data
	br := mb.store.getPooledReader(file)
	defer mb.store.putPooledReader(br)
	dec := gob.NewDecoder(br)
	name := ""
	if err = dec.Decode(&name); err != nil {
		return fmt.Errorf("corrupt mailbox %q: %v", mb.indexPath, err)
	}
	mb.name = name
	for {
		// Load messages until EOF
		msg := &Message{}
		if err = dec.Decode(msg); err != nil {
			if err == io.EOF {
				break
			}
			return fmt.Errorf("corrupt mailbox %q: %v", mb.indexPath, err)
		}
		msg.mailbox = mb
		mb.messages = append(mb.messages, msg)
	}
	mb.indexLoaded = true
	return nil
}