65 lines
1.2 KiB
Go
65 lines
1.2 KiB
Go
package event
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import (
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"log/slog"
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"slices"
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"sync"
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)
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const defaultChannelSize = 64
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// Bus is an event bus.
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type Bus struct {
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consumers []chan Event
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mu sync.Mutex
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logger *slog.Logger
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}
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// NewBus returns a new event bus.
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func NewBus(logger *slog.Logger) *Bus {
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return &Bus{
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logger: logger,
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}
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}
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// Register registers a consumer for all events.
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func (b *Bus) Register() <-chan Event {
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b.mu.Lock()
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defer b.mu.Unlock()
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ch := make(chan Event, defaultChannelSize)
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b.consumers = append(b.consumers, ch)
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return ch
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}
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func (b *Bus) Deregister(ch <-chan Event) {
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b.mu.Lock()
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defer b.mu.Unlock()
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b.consumers = slices.DeleteFunc(b.consumers, func(other chan Event) bool {
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if ch == other {
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close(other)
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return true
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}
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return false
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})
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}
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// Send sends an event to all registered consumers.
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func (b *Bus) Send(evt Event) {
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// The mutex is needed to ensure the backing array of b.consumers cannot be
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// modified under our feet. There is probably a more efficient way to do this
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// but this should be ok.
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b.mu.Lock()
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defer b.mu.Unlock()
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for _, ch := range b.consumers {
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select {
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case ch <- evt:
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default:
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b.logger.Warn("Event dropped", "name", evt.name())
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}
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}
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}
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