forked from iotaledger/hive.go
/
event.go
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/
event.go
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package events
import (
"go.uber.org/atomic"
"github.com/izuc/zipp.foundation/core/datastructure/orderedmap"
reflectpkg "github.com/izuc/zipp.foundation/core/reflect"
)
// Event represents an object that is triggered to notify code of "interesting updates" that may affect its behavior.
type Event struct {
triggerFunc func(handler interface{}, params ...interface{})
beforeHooks *orderedmap.OrderedMap
hooks *orderedmap.OrderedMap
afterHooks *orderedmap.OrderedMap
}
// NewEvent is the constructor of an Event.
func NewEvent(triggerFunc func(handler interface{}, params ...interface{})) *Event {
return &Event{
triggerFunc: triggerFunc,
beforeHooks: orderedmap.New(),
hooks: orderedmap.New(),
afterHooks: orderedmap.New(),
}
}
func (ev *Event) attachCallback(callbacks *orderedmap.OrderedMap, closure *Closure, triggerMaxCount ...uint64) {
callbackFunc := closure.Fnc
if (len(triggerMaxCount) > 0) && (triggerMaxCount[0] > 0) {
// a trigger limit was specified
triggerCount := atomic.NewUint64(0)
// wrap the Closure Function to automatically detach the Closure from the event after exceeding the trigger limit.
callbackFunc = reflectpkg.FuncPostCallback(closure.Fnc, func() {
if triggerCount.Inc() >= triggerMaxCount[0] {
ev.DetachID(closure.ID)
}
})
}
callbacks.Set(closure.ID, callbackFunc)
}
// HookBefore allows to register a Closure that is executed before the Event triggers.
// If 'triggerMaxCount' is >0, the Closure is automatically detached after exceeding the trigger limit.
func (ev *Event) HookBefore(closure *Closure, triggerMaxCount ...uint64) {
if closure == nil {
return
}
ev.attachCallback(ev.beforeHooks, closure, triggerMaxCount...)
}
// Hook allows to register a Closure that is executed when the Event triggers.
// If 'triggerMaxCount' is >0, the Closure is automatically detached after exceeding the trigger limit.
func (ev *Event) Hook(closure *Closure, triggerMaxCount ...uint64) {
if closure == nil {
return
}
ev.attachCallback(ev.hooks, closure, triggerMaxCount...)
}
// HookAfter allows to register a Closure that is executed after the Event triggered.
// If 'triggerMaxCount' is >0, the Closure is automatically detached after exceeding the trigger limit.
func (ev *Event) HookAfter(closure *Closure, triggerMaxCount ...uint64) {
if closure == nil {
return
}
ev.attachCallback(ev.afterHooks, closure, triggerMaxCount...)
}
// DetachID allows to unregister a Closure ID that was previously registered.
func (ev *Event) DetachID(closureID uint64) {
ev.beforeHooks.Delete(closureID)
ev.hooks.Delete(closureID)
ev.afterHooks.Delete(closureID)
}
// Detach allows to unregister a Closure that was previously registered.
func (ev *Event) Detach(closure *Closure) {
if closure == nil {
return
}
ev.DetachID(closure.ID)
}
// Trigger calls the registered callbacks with the given parameters.
func (ev *Event) Trigger(params ...interface{}) {
ev.beforeHooks.ForEach(func(_, handler interface{}) bool {
ev.triggerFunc(handler, params...)
return true
})
ev.hooks.ForEach(func(_, handler interface{}) bool {
ev.triggerFunc(handler, params...)
return true
})
ev.afterHooks.ForEach(func(_, handler interface{}) bool {
ev.triggerFunc(handler, params...)
return true
})
}
// DetachAll removes all registered callbacks.
func (ev *Event) DetachAll() {
ev.beforeHooks.Clear()
ev.hooks.Clear()
ev.afterHooks.Clear()
}