Horrible hack for bad architecture

internal/store/maildir.go

@@ -5,6 +5,7 @@ import (
 	"net/mail"
 	"os"
 	"path/filepath"
+	"sync"
 
 	"github.com/luksen/maildir"
 
@@ -55,21 +56,38 @@ func (c *concrete) CreateMaildir(m *Maildir) error {
 	}
 
 	if m.uids == nil {
-		uids, err := uidlist.Create(m.directory)
-		if err != nil {
-			// FIXME: this leaves a dangling Maildir
-			return err
+		uidsLock.Lock()
+		defer uidsLock.Unlock()
+
+		if uidsCache[m.Rel()] == nil {
+
+			uids, err := uidlist.Create(m.directory)
+			if err != nil {
+				// FIXME: this leaves a dangling Maildir
+				return err
+			}
+			uidsCache[m.Rel()] = uids
 		}
 
-		m.uids = uids
+		m.uids = uidsCache[m.Rel()]
 	}
 
 	return nil
 }
 
+// Ugh
+// FIXME: multiple sessions get different Maildir instances, so breaking any
+// hope at locking (sigh)
+var (
+	uidsLock  sync.Mutex
+	uidsCache map[string]*uidlist.List
+)
+
+func init() {
+	uidsCache = make(map[string]*uidlist.List)
+}
+
 func (c *concrete) FindMaildir(account Account, name string) (Maildir, error) {
-	// FIXME: multiple IMAP sessions get different Maildir instances, so breaking
-	// any hope at locking (sigh)
 	m := Maildir{
 		Account:   account,
 		Name:      name,
@@ -81,11 +99,17 @@ func (c *concrete) FindMaildir(account Account, name string) (Maildir, error) {
 		return Maildir{}, errors.New("not found")
 	}
 
-	uids, err := uidlist.Open(m.directory)
-	if err != nil {
-		return Maildir{}, err
+	uidsLock.Lock()
+	defer uidsLock.Unlock()
+	if uidsCache[m.Rel()] == nil {
+		uids, err := uidlist.Open(m.directory)
+		if err != nil {
+			return Maildir{}, err
+		}
+		uidsCache[m.Rel()] = uids
 	}
-	m.uids = uids
+
+	m.uids = uidsCache[m.Rel()]
 
 	return m, nil
 }