55 lines
972 B
Go
55 lines
972 B
Go
package emitter
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import "git.maximhutz.com/max/lambda/pkg/set"
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type Observer[T any] struct {
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fn func(T)
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message string
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emitter *Emitter[T]
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}
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type Emitter[T any] struct {
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listeners map[string]*set.Set[*Observer[T]]
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}
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func Ignore[T any](fn func()) func(T) {
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return func(T) { fn() }
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}
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func (e *Emitter[T]) On(message string, fn func(T)) *Observer[T] {
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observer := &Observer[T]{
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fn: fn,
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message: message,
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emitter: e,
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}
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if e.listeners == nil {
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e.listeners = map[string]*set.Set[*Observer[T]]{}
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}
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if e.listeners[message] == nil {
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e.listeners[message] = set.New[*Observer[T]]()
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}
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e.listeners[message].Add(observer)
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return observer
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}
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func (o *Observer[T]) Off() {
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if o.emitter.listeners[o.message] == nil {
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return
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}
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o.emitter.listeners[o.message].Remove(o)
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}
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func (e *Emitter[T]) Emit(message string, value T) {
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if e.listeners[message] == nil {
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return
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}
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for listener := range *e.listeners[message] {
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listener.fn(value)
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}
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}
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