file: Remove index and dir mutexes

HashLock makes these redundant.  #77

pkg/storage/file/fmessage.go

@@ -1,7 +1,6 @@
 package file
 
 import (
-	"bufio"
 	"io"
 	"net/mail"
 	"os"
@@ -22,10 +21,6 @@ type Message struct {
 	Fto      []*mail.Address
 	Fsubject string
 	Fsize    int64
-	// These are for creating new messages only
-	writable   bool
-	writerFile *os.File
-	writer     *bufio.Writer
 }
 
 // newMessage creates a new FileMessage object and sets the Date and ID fields.
@@ -48,7 +43,7 @@ func (mb *mbox) newMessage() (*Message, error) {
 	}
 	date := time.Now()
 	id := generateID(date)
-	return &Message{mailbox: mb, Fid: id, Fdate: date, writable: true}, nil
+	return &Message{mailbox: mb, Fid: id, Fdate: date}, nil
 }
 
 // Mailbox returns the name of the mailbox this message resides in.

pkg/storage/file/fstore.go

@@ -7,7 +7,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"sync"
 	"time"
 
 	"github.com/jhillyerd/inbucket/pkg/config"
@@ -21,15 +20,6 @@ import (
 const indexFileName = "index.gob"
 
 var (
-	// indexMx is locked while reading/writing an index file
-	//
-	// NOTE: This is a bottleneck because it's a single lock even if we have a
-	// million index files
-	indexMx = new(sync.RWMutex)
-
-	// dirMx is locked while creating/removing directories
-	dirMx = new(sync.Mutex)
-
 	// countChannel is filled with a sequential numbers (0000..9999), which are
 	// used by generateID() to generate unique message IDs.  It's global
 	// because we only want one regardless of the number of DataStore objects

pkg/storage/file/mbox.go

@@ -101,9 +101,6 @@ func (mb *mbox) purge() error {
 func (mb *mbox) readIndex() error {
 	// Clear message slice, open index
 	mb.messages = mb.messages[:0]
-	// Lock for reading
-	indexMx.RLock()
-	defer indexMx.RUnlock()
 	// Check if index exists
 	if _, err := os.Stat(mb.indexPath); err != nil {
 		// Does not exist, but that's not an error in our world
@@ -146,8 +143,6 @@ func (mb *mbox) readIndex() error {
 // writeIndex overwrites the index on disk with the current mailbox data
 func (mb *mbox) writeIndex() error {
 	// Lock for writing
-	indexMx.Lock()
-	defer indexMx.Unlock()
 	if len(mb.messages) > 0 {
 		// Ensure mailbox directory exists
 		if err := mb.createDir(); err != nil {
@@ -189,8 +184,6 @@ func (mb *mbox) writeIndex() error {
 
 // createDir checks for the presence of the path for this mailbox, creates it if needed
 func (mb *mbox) createDir() error {
-	dirMx.Lock()
-	defer dirMx.Unlock()
 	if _, err := os.Stat(mb.path); err != nil {
 		if err := os.MkdirAll(mb.path, 0770); err != nil {
 			log.Errorf("Failed to create directory %v, %v", mb.path, err)
@@ -202,8 +195,6 @@ func (mb *mbox) createDir() error {
 
 // removeDir removes the mailbox, plus empty higher level directories
 func (mb *mbox) removeDir() error {
-	dirMx.Lock()
-	defer dirMx.Unlock()
 	// remove mailbox dir, including index file
 	if err := os.RemoveAll(mb.path); err != nil {
 		return err
@@ -217,7 +208,7 @@ func (mb *mbox) removeDir() error {
 }
 
 // removeDirIfEmpty will remove the specified directory if it contains no files or directories.
-// Caller should hold dirMx.  Returns true if dir was removed.
+// Returns true if dir was removed.
 func removeDirIfEmpty(path string) (removed bool) {
 	f, err := os.Open(path)
 	if err != nil {