mirror of
https://github.com/anchore/syft.git
synced 2026-10-30 14:02:26 +01:00
31 lines
864 B
Go
31 lines
864 B
Go
package index
|
|
|
|
import (
|
|
"reflect"
|
|
"sync"
|
|
)
|
|
|
|
// lockable is a read-write lock that returns its own unlock function.
|
|
//
|
|
// Handing back an opaque unlocker (rather than exposing Unlock) lets a node tell whether the caller
|
|
// holds the read or write lock and upgrade only when needed. Carried over from the prototype index.
|
|
type lockable struct {
|
|
lock sync.RWMutex
|
|
}
|
|
|
|
func (l *lockable) Lock() (unlock func()) {
|
|
l.lock.Lock()
|
|
return l.lock.Unlock
|
|
}
|
|
|
|
func (l *lockable) RLock() (unlock func()) {
|
|
l.lock.RLock()
|
|
return l.lock.RUnlock
|
|
}
|
|
|
|
// isExclusiveLock reports whether the given unlocker is the write lock's rather than the read
|
|
// lock's. Compared by function pointer because that is the only handle the caller was given.
|
|
func (l *lockable) isExclusiveLock(fn func()) bool {
|
|
return reflect.ValueOf(l.lock.Unlock).Pointer() == reflect.ValueOf(fn).Pointer()
|
|
}
|