Use Channel instead of purgerWaitGroup

pond.go

@@ -91,7 +91,7 @@ type WorkerPool struct {
 	tasks            chan func()
 	workersWaitGroup sync.WaitGroup
 	tasksWaitGroup   sync.WaitGroup
-	purgerWaitGroup  sync.WaitGroup
+	purgerDoneChan   chan struct{}
 	mutex            sync.Mutex
 	stopped          bool
 }
@@ -139,7 +139,7 @@ func New(maxWorkers, maxCapacity int, options ...Option) *WorkerPool {
 	pool.tasks = make(chan func(), pool.maxCapacity)
 
 	// Start purger goroutine
-	pool.purgerWaitGroup.Add(1)
+	pool.purgerDoneChan = make(chan struct{})
 	go pool.purge()
 
 	// Start minWorkers workers
@@ -333,13 +333,13 @@ func (p *WorkerPool) SubmitBefore(task func(), deadline time.Duration) {
 // Stop causes this pool to stop accepting new tasks and signals all workers to stop processing new tasks.
 // Tasks being processed by workers will continue until completion unless the process is terminated.
 func (p *WorkerPool) Stop() {
-	p.stop(false)
+	go p.stop()
 }
 
 // StopAndWait causes this pool to stop accepting new tasks and then waits for all tasks in the queue
 // to complete before returning.
 func (p *WorkerPool) StopAndWait() {
-	p.stop(true)
+	p.stop()
 }
 
 // StopAndWaitFor stops this pool and waits for all tasks in the queue to complete before returning
@@ -349,7 +349,7 @@ func (p *WorkerPool) StopAndWaitFor(deadline time.Duration) {
 	// Launch goroutine to detect when worker pool has stopped gracefully
 	workersDone := make(chan struct{})
 	go func() {
-		p.stop(true)
+		p.stop()
 		workersDone <- struct{}{}
 	}()
 
@@ -363,30 +363,29 @@ func (p *WorkerPool) StopAndWaitFor(deadline time.Duration) {
 	}
 }
 
-func (p *WorkerPool) stop(waitForCompletion bool) {
-
+func (p *WorkerPool) stop() {
 	// Mark pool as stopped
 	p.stopped = true
 
 	// Wait for all queued tasks to complete
-	if waitForCompletion {
-		p.tasksWaitGroup.Wait()
-	}
+	p.tasksWaitGroup.Wait()
 
 	// Terminate all workers & purger goroutine
 	p.contextCancel()
 
 	// Wait for all workers to exit
-	if waitForCompletion {
-		p.workersWaitGroup.Wait()
-		p.purgerWaitGroup.Wait()
-		close(p.tasks)
-	}
+	p.workersWaitGroup.Wait()
+
+	// Wait purger goroutine to exit
+	<-p.purgerDoneChan
+
+	// close tasks channel
+	close(p.tasks)
 }
 
 // purge represents the work done by the purger goroutine
 func (p *WorkerPool) purge() {
-	defer p.purgerWaitGroup.Done()
+	defer func() { p.purgerDoneChan <- struct{}{} }()
 
 	idleTicker := time.NewTicker(p.idleTimeout)
 	defer idleTicker.Stop()