go.mod: github.com/alexflint/go-filemutex v1.1.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/github.com/alexflint/go-filemutex/filemutex_flock.go

@@ -35,6 +35,18 @@ func (m *FileMutex) Lock() error {
 	return nil
 }
 
+func (m *FileMutex) TryLock() error {
+	if err := syscall.Flock(m.fd, syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
+		if errno, ok := err.(syscall.Errno); ok {
+			if errno == syscall.EWOULDBLOCK {
+				return AlreadyLocked
+			}
+		}
+		return err
+	}
+	return nil
+}
+
 func (m *FileMutex) Unlock() error {
 	if err := syscall.Flock(m.fd, syscall.LOCK_UN); err != nil {
 		return err
@@ -56,9 +68,7 @@ func (m *FileMutex) RUnlock() error {
 	return nil
 }
 
-// Close does an Unlock() combined with closing and unlinking the associated
-// lock file. You should create a New() FileMutex for every Lock() attempt if
-// using Close().
+// Close unlocks the lock and closes the underlying file descriptor.
 func (m *FileMutex) Close() error {
 	if err := syscall.Flock(m.fd, syscall.LOCK_UN); err != nil {
 		return err