98 lines
1.5 KiB
Go
98 lines
1.5 KiB
Go
package main
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import (
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"sync"
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)
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type (
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request struct {
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queues []string
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responseCh chan response
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abort chan bool
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dead bool
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}
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response struct {
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queue string
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message message
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}
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)
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var (
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pool struct {
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requests []*request
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mutex sync.Mutex
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}
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)
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func registerPublication(q string, msg message) bool {
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for _, r := range pool.requests {
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if r.dead {
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continue
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}
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for _, qname := range r.queues {
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if qname == q {
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rsp := response{queue: q, message: msg}
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ok := r.tryRespond(rsp)
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if ok {
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return true
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}
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}
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}
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}
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ok := getQueue(q).push(msg)
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return ok
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}
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func registerSubscription(r *request) {
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for _, qname := range r.queues {
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q := getQueue(qname)
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msg, ok := q.tryFetch(r.abort)
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if ok {
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rsp := response{queue: qname, message: msg}
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ok := r.tryRespond(rsp)
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if !ok {
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q.push(msg)
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}
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return
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}
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}
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pool.requests = append(pool.requests, r)
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}
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func (r *request) tryRespond(rsp response) bool {
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okch := make(chan bool)
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go func() {
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defer func() {
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err := recover()
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if err != nil { // Panic!
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r.dead = true
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okch <- false
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}
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}()
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r.responseCh <- rsp // If channel is already closed expect a panic
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okch <- true
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}()
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ok := <-okch
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return ok
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}
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func (r *request) purge() {
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pool.mutex.Lock()
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defer pool.mutex.Unlock()
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r.dead = true
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deleted := 0
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for i, req := range pool.requests {
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if req.dead {
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pool.requests = append(pool.requests[:i-deleted], pool.requests[i-deleted+1:]...)
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deleted++
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}
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}
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}
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