1
mirror of https://github.com/rclone/rclone synced 2024-12-11 23:54:00 +01:00
rclone/backend/sftp/stringlock.go

50 lines
982 B
Go

// +build !plan9,go1.9
package sftp
import "sync"
// stringLock locks for string IDs passed in
type stringLock struct {
mu sync.Mutex // mutex to protect below
locks map[string]chan struct{} // map of locks
}
// newStringLock creates a stringLock
func newStringLock() *stringLock {
return &stringLock{
locks: make(map[string]chan struct{}),
}
}
// Lock locks on the id passed in
func (l *stringLock) Lock(ID string) {
l.mu.Lock()
for {
ch, ok := l.locks[ID]
if !ok {
break
}
// Wait for the channel to be closed
l.mu.Unlock()
// fs.Logf(nil, "Waiting for stringLock on %q", ID)
<-ch
l.mu.Lock()
}
l.locks[ID] = make(chan struct{})
l.mu.Unlock()
}
// Unlock unlocks on the id passed in. Will panic if Lock with the
// given id wasn't called first.
func (l *stringLock) Unlock(ID string) {
l.mu.Lock()
ch, ok := l.locks[ID]
if !ok {
panic("stringLock: Unlock before Lock")
}
close(ch)
delete(l.locks, ID)
l.mu.Unlock()
}