69 lines
1.7 KiB
Go
69 lines
1.7 KiB
Go
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package raft
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import (
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"reflect"
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"sync"
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)
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// eventDispatcher is responsible for managing listeners for named events
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// and dispatching event notifications to those listeners.
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type eventDispatcher struct {
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sync.RWMutex
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source interface{}
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listeners map[string]eventListeners
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}
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// EventListener is a function that can receive event notifications.
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type EventListener func(Event)
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// EventListeners represents a collection of individual listeners.
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type eventListeners []EventListener
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// newEventDispatcher creates a new eventDispatcher instance.
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func newEventDispatcher(source interface{}) *eventDispatcher {
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return &eventDispatcher{
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source: source,
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listeners: make(map[string]eventListeners),
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}
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}
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// AddEventListener adds a listener function for a given event type.
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func (d *eventDispatcher) AddEventListener(typ string, listener EventListener) {
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d.Lock()
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defer d.Unlock()
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d.listeners[typ] = append(d.listeners[typ], listener)
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}
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// RemoveEventListener removes a listener function for a given event type.
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func (d *eventDispatcher) RemoveEventListener(typ string, listener EventListener) {
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d.Lock()
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defer d.Unlock()
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// Grab a reference to the function pointer once.
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ptr := reflect.ValueOf(listener).Pointer()
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// Find listener by pointer and remove it.
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listeners := d.listeners[typ]
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for i, l := range listeners {
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if reflect.ValueOf(l).Pointer() == ptr {
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d.listeners[typ] = append(listeners[:i], listeners[i+1:]...)
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}
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}
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}
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// DispatchEvent dispatches an event.
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func (d *eventDispatcher) DispatchEvent(e Event) {
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d.RLock()
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defer d.RUnlock()
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// Automatically set the event source.
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if e, ok := e.(*event); ok {
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e.source = d.source
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}
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// Dispatch the event to all listeners.
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for _, l := range d.listeners[e.Type()] {
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l(e)
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}
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}
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