45 lines
974 B
Go
45 lines
974 B
Go
package gubgub
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import "sync"
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// SyncTopic allows any message T to be broadcast to subscribers. Publishing and Subscribing
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// happens synchronously (block).
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type SyncTopic[T any] struct {
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mu sync.Mutex
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subscribers []Subscriber[T]
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}
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// NewSyncTopic creates a zero SyncTopic and return a pointer to it.
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func NewSyncTopic[T any]() *SyncTopic[T] {
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return &SyncTopic[T]{}
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}
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// Publish broadcasts a message to all subscribers.
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func (t *SyncTopic[T]) Publish(msg T) error {
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t.mu.Lock()
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defer t.mu.Unlock()
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keepers := make([]Subscriber[T], 0, len(t.subscribers))
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for _, callback := range t.subscribers {
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keep := callback(msg)
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if keep {
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keepers = append(keepers, callback)
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}
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}
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t.subscribers = keepers
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return nil
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}
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// Subscribe adds a Subscriber func that will consume future published messages.
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func (t *SyncTopic[T]) Subscribe(fn Subscriber[T]) error {
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t.mu.Lock()
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defer t.mu.Unlock()
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t.subscribers = append(t.subscribers, fn)
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return nil
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}
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