forked from mirrors/gotosocial
b8879ac68a
* update go-store, go-mutexes Signed-off-by: kim <grufwub@gmail.com> * update vendored code Signed-off-by: kim <grufwub@gmail.com>
51 lines
1.1 KiB
Go
51 lines
1.1 KiB
Go
package mutexes
|
|
|
|
import (
|
|
"sync/atomic"
|
|
)
|
|
|
|
// WithSafety wrapps the supplied Mutex to protect unlock fns
|
|
// from being called multiple times
|
|
func WithSafety(mu Mutex) Mutex {
|
|
return &safeMutex{mu: mu}
|
|
}
|
|
|
|
// WithSafetyRW wrapps the supplied RWMutex to protect unlock
|
|
// fns from being called multiple times
|
|
func WithSafetyRW(mu RWMutex) RWMutex {
|
|
return &safeRWMutex{mu: mu}
|
|
}
|
|
|
|
// safeMutex simply wraps a Mutex to add multi-unlock safety
|
|
type safeMutex struct{ mu Mutex }
|
|
|
|
func (mu *safeMutex) Lock() func() {
|
|
unlock := mu.mu.Lock()
|
|
return once(unlock)
|
|
}
|
|
|
|
// safeRWMutex simply wraps a RWMutex to add multi-unlock safety
|
|
type safeRWMutex struct{ mu RWMutex }
|
|
|
|
func (mu *safeRWMutex) Lock() func() {
|
|
unlock := mu.mu.Lock()
|
|
return once(unlock)
|
|
}
|
|
|
|
func (mu *safeRWMutex) RLock() func() {
|
|
unlock := mu.mu.RLock()
|
|
return once(unlock)
|
|
}
|
|
|
|
// once will perform 'do' only once, this is safe for unlocks
|
|
// as 2 functions calling 'unlock()' don't need absolute guarantees
|
|
// that by the time it is completed the unlock was finished.
|
|
func once(do func()) func() {
|
|
var done uint32
|
|
return func() {
|
|
if atomic.CompareAndSwapUint32(&done, 0, 1) {
|
|
do()
|
|
}
|
|
}
|
|
}
|