photoprism/internal/mutex/activity.go

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package mutex
import (
"errors"
"sync"
)
// Activity represents work that can be started and stopped.
type Activity struct {
busy bool
canceled bool
mutex sync.Mutex
}
// Running checks if the Activity is currently running.
func (b *Activity) Running() bool {
b.mutex.Lock()
defer b.mutex.Unlock()
return b.busy
}
// Start marks the Activity as started and returns an error if it is already running.
func (b *Activity) Start() error {
b.mutex.Lock()
defer b.mutex.Unlock()
if b.canceled {
return errors.New("still running")
}
if b.busy {
return errors.New("already running")
}
b.busy = true
b.canceled = false
return nil
}
// Stop marks the Activity as stopped.
func (b *Activity) Stop() {
b.mutex.Lock()
defer b.mutex.Unlock()
b.busy = false
b.canceled = false
}
// Cancel requests to stop the Activity.
func (b *Activity) Cancel() {
b.mutex.Lock()
defer b.mutex.Unlock()
if b.busy {
b.canceled = true
}
}
// Canceled marks the Activity as stopped.
func (b *Activity) Canceled() bool {
b.mutex.Lock()
defer b.mutex.Unlock()
return b.canceled
}