From 8ea610c6250c65888b6de4febc404f29b12008c8 Mon Sep 17 00:00:00 2001
From: James Houlahan <james.houlahan@proton.ch>
Date: Mon, 4 Oct 2021 08:22:40 +0200
Subject: [PATCH] GODT-1367: Use sync.Once to only close pool jobs once

---
 pkg/pchan/pchan.go |  9 ++-------
 pkg/pool/pool.go   | 15 +++++++--------
 2 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/pkg/pchan/pchan.go b/pkg/pchan/pchan.go
index b353a6a6..5348bf0d 100644
--- a/pkg/pchan/pchan.go
+++ b/pkg/pchan/pchan.go
@@ -26,6 +26,7 @@ type PChan struct {
 	lock        sync.Mutex
 	items       []*Item
 	ready, done chan struct{}
+	once        sync.Once
 }
 
 type Item struct {
@@ -82,13 +83,7 @@ func (ch *PChan) Pop() (interface{}, int, bool) {
 }
 
 func (ch *PChan) Close() {
-	select {
-	case <-ch.done:
-		return
-
-	default:
-		close(ch.done)
-	}
+	ch.once.Do(func() { close(ch.done) })
 }
 
 func (ch *PChan) push(val interface{}, prio int) *Item {
diff --git a/pkg/pool/pool.go b/pkg/pool/pool.go
index 2b67fe54..3bf84d46 100644
--- a/pkg/pool/pool.go
+++ b/pkg/pool/pool.go
@@ -17,7 +17,11 @@
 
 package pool
 
-import "github.com/ProtonMail/proton-bridge/pkg/pchan"
+import (
+	"sync"
+
+	"github.com/ProtonMail/proton-bridge/pkg/pchan"
+)
 
 type WorkFunc func(interface{}, int) (interface{}, error)
 
@@ -74,6 +78,7 @@ type Job struct {
 	item *pchan.Item
 
 	ready, done chan struct{}
+	once        sync.Once
 }
 
 func newJob(req interface{}) *Job {
@@ -115,13 +120,7 @@ func (job *Job) setItem(item *pchan.Item) {
 }
 
 func (job *Job) markDone() {
-	select {
-	case <-job.done:
-		return
-
-	default:
-		close(job.done)
-	}
+	job.once.Do(func() { close(job.done) })
 }
 
 func (job *Job) waitDone() {