mirror of https://github.com/nealey/vail.git
101 lines
1.8 KiB
Go
101 lines
1.8 KiB
Go
package main
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import (
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"log"
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)
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// Book maps names to repeaters
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//
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// It ensures that names map 1-1 to repeaters.
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type Book struct {
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entries map[string]*Repeater
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events chan bookEvent
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makeRepeater func() *Repeater
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}
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func NewBook() Book {
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return Book{
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entries: make(map[string]*Repeater),
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events: make(chan bookEvent, 5),
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makeRepeater: NewRepeater,
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}
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}
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type bookEventType int
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const (
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joinEvent = bookEventType(iota)
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partEvent
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sendEvent
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)
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type bookEvent struct {
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eventType bookEventType
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name string
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sender MessageSender
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m Message
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}
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// Join adds a writer to a named repeater
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func (b Book) Join(name string, sender MessageSender) {
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b.events <- bookEvent{
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eventType: joinEvent,
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name: name,
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sender: sender,
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}
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}
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// Part removes a writer from a named repeater
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func (b Book) Part(name string, sender MessageSender) {
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b.events <- bookEvent{
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eventType: partEvent,
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name: name,
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sender: sender,
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}
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}
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// Send transmits a message to the named repeater
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func (b Book) Send(name string, m Message) {
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b.events <- bookEvent{
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eventType: sendEvent,
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name: name,
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m: m,
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}
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}
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// Run is the endless run loop
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func (b Book) Run() {
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for {
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b.loop()
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}
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}
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func (b Book) loop() {
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event := <-b.events
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repeater, ok := b.entries[event.name]
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switch event.eventType {
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case joinEvent:
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if !ok {
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repeater = b.makeRepeater()
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b.entries[event.name] = repeater
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}
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repeater.Join(event.sender)
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case partEvent:
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if !ok {
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log.Println("WARN: Parting an empty channel:", event.name)
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break
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}
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repeater.Part(event.sender)
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if repeater.Listeners() == 0 {
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delete(b.entries, event.name)
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}
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case sendEvent:
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if !ok {
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log.Println("WARN: Sending to an empty channel:", event.name)
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break
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}
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repeater.Send(event.m)
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}
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}
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