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authorRené 'Necoro' Neumann <necoro@necoro.eu>2020-04-23 23:47:05 +0200
committerRené 'Necoro' Neumann <necoro@necoro.eu>2020-04-23 23:47:05 +0200
commit6911562cf4214531343b7509afe77e38b28a0801 (patch)
tree46601b14d15b781c373a99f32880334b10092c68
parentc1fbae6e0f5981d4d60f5b614d5d195ae5cde4a8 (diff)
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Fix concurrent access to the same folder
Diffstat (limited to '')
-rw-r--r--internal/imap/connection.go7
-rw-r--r--internal/imap/mailboxes.go41
2 files changed, 43 insertions, 5 deletions
diff --git a/internal/imap/connection.go b/internal/imap/connection.go
index 88b1496..358445b 100644
--- a/internal/imap/connection.go
+++ b/internal/imap/connection.go
@@ -99,6 +99,13 @@ func (conn *connection) ensureFolder(folder Folder) error {
return nil
}
+ if conn.mailboxes.locking(folder) {
+ // someone else tried to create the MB -- try again, now that he's done
+ return conn.ensureFolder(folder)
+ } else {
+ defer conn.mailboxes.unlocking(folder)
+ }
+
log.Printf("Checking for folder '%s'", folder)
mbox, found, err := conn.list(folder.str)
diff --git a/internal/imap/mailboxes.go b/internal/imap/mailboxes.go
index d0fdede..f1dc6c6 100644
--- a/internal/imap/mailboxes.go
+++ b/internal/imap/mailboxes.go
@@ -7,8 +7,38 @@ import (
)
type mailboxes struct {
- mb map[string]*imap.MailboxInfo
- mu sync.RWMutex
+ mb map[string]*imap.MailboxInfo
+ mu sync.RWMutex
+ changeLocks map[string]chan struct{}
+}
+
+func (mbs *mailboxes) unlocking(elem Folder) {
+ mbs.mu.Lock()
+ defer mbs.mu.Unlock()
+
+ ch, ok := mbs.changeLocks[elem.str]
+ if !ok {
+ panic("Unlocking where nothing is locked")
+ }
+ close(ch)
+ delete(mbs.changeLocks, elem.str)
+}
+
+func (mbs *mailboxes) locking(elem Folder) bool {
+ mbs.mu.Lock()
+ ch, ok := mbs.changeLocks[elem.str]
+ if !ok {
+ ch = make(chan struct{})
+ mbs.changeLocks[elem.str] = ch
+ mbs.mu.Unlock()
+ // we created the lock, we are in charge and done here
+ return false
+ } else {
+ // someone else is working, we wait till he's done
+ mbs.mu.Unlock() // we are not doing anything...
+ <-ch
+ return true
+ }
}
func (mbs *mailboxes) contains(elem Folder) bool {
@@ -28,7 +58,8 @@ func (mbs *mailboxes) add(elem *imap.MailboxInfo) {
func NewMailboxes() *mailboxes {
return &mailboxes{
- mb: map[string]*imap.MailboxInfo{},
- mu: sync.RWMutex{},
+ mb: map[string]*imap.MailboxInfo{},
+ changeLocks: map[string]chan struct{}{},
+ mu: sync.RWMutex{},
}
-} \ No newline at end of file
+}