From de61fd912d0de341e7d3a7225999fc68f2aaab4f Mon Sep 17 00:00:00 2001
From: diamondburned <datutbrus@gmail.com>
Date: Wed, 19 Aug 2020 20:48:55 -0700
Subject: [PATCH] wsutil: Made PacemakerLoop valid as zero-value

---
 gateway/gateway.go            | 16 ++++++----------
 gateway/op.go                 |  1 -
 utils/wsutil/heart.go         | 19 +++++++++----------
 voice/voicegateway/gateway.go |  5 +----
 4 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/gateway/gateway.go b/gateway/gateway.go
index 222d83b..b044584 100644
--- a/gateway/gateway.go
+++ b/gateway/gateway.go
@@ -85,11 +85,14 @@ type Gateway struct {
 	// Session.
 	Events chan Event
 
+	// SessionID is used to store the session ID received after Ready. It is not
+	// thread-safe.
 	SessionID string
 
 	Identifier *Identifier
 	Sequence   *Sequence
-	PacerLoop  *wsutil.PacemakerLoop
+
+	PacerLoop wsutil.PacemakerLoop
 
 	ErrorLog func(err error) // default to log.Println
 
@@ -98,11 +101,6 @@ type Gateway struct {
 	// reconnections or any type of connection interruptions.
 	AfterClose func(err error) // noop by default
 
-	// Mutex to hold off calls when the WS is not available. Doesn't block if
-	// Start() is not called or Close() is called. Also doesn't block for
-	// Identify or Resume.
-	// available sync.RWMutex
-
 	// Filled by methods, internal use
 	waitGroup *sync.WaitGroup
 }
@@ -356,13 +354,11 @@ func (g *Gateway) start(ctx context.Context) error {
 		return errors.Wrap(err, "first error")
 	}
 
-	// Use the pacemaker loop.
-	g.PacerLoop = wsutil.NewLoop(hello.HeartbeatInterval.Duration(), ch, g)
-
 	// Start the event handler, which also handles the pacemaker death signal.
 	g.waitGroup.Add(1)
 
-	g.PacerLoop.RunAsync(func(err error) {
+	// Use the pacemaker loop.
+	g.PacerLoop.RunAsync(hello.HeartbeatInterval.Duration(), ch, g, func(err error) {
 		g.waitGroup.Done() // mark so Close() can exit.
 		wsutil.WSDebug("Event loop stopped with error:", err)
 
diff --git a/gateway/op.go b/gateway/op.go
index 2d6e0d6..e5d5b45 100644
--- a/gateway/op.go
+++ b/gateway/op.go
@@ -71,7 +71,6 @@ func (g *Gateway) HandleOP(op *wsutil.OP) error {
 		return nil
 
 	case HelloOP:
-		// What is this OP doing here???
 		return nil
 
 	case DispatchOP:
diff --git a/utils/wsutil/heart.go b/utils/wsutil/heart.go
index 348e1ba..e4d9f69 100644
--- a/utils/wsutil/heart.go
+++ b/utils/wsutil/heart.go
@@ -16,7 +16,8 @@ type EventLoopHandler interface {
 	HeartbeatCtx(context.Context) error
 }
 
-// PacemakerLoop provides an event loop with a pacemaker.
+// PacemakerLoop provides an event loop with a pacemaker. A zero-value instance
+// is a valid instance only when RunAsync is called first.
 type PacemakerLoop struct {
 	pacemaker *heart.Pacemaker // let's not copy this
 	pacedeath chan error
@@ -31,14 +32,6 @@ type PacemakerLoop struct {
 	ErrorLog func(error)
 }
 
-func NewLoop(heartrate time.Duration, evs <-chan Event, evl EventLoopHandler) *PacemakerLoop {
-	return &PacemakerLoop{
-		pacemaker: heart.NewPacemaker(heartrate, evl.HeartbeatCtx),
-		events:    evs,
-		handler:   evl.HandleOP,
-	}
-}
-
 func (p *PacemakerLoop) errorLog(err error) {
 	if p.ErrorLog == nil {
 		WSDebug("Uncaught error:", err)
@@ -67,9 +60,15 @@ func (p *PacemakerLoop) Stopped() bool {
 	return p == nil || !p.running.Get()
 }
 
-func (p *PacemakerLoop) RunAsync(exit func(error)) {
+func (p *PacemakerLoop) RunAsync(
+	heartrate time.Duration, evs <-chan Event, evl EventLoopHandler, exit func(error)) {
+
 	WSDebug("Starting the pacemaker loop.")
 
+	p.pacemaker = heart.NewPacemaker(heartrate, evl.HeartbeatCtx)
+	p.events = evs
+	p.handler = evl.HandleOP
+
 	// callers should explicitly handle waitgroups.
 	p.pacedeath = p.pacemaker.StartAsync(nil)
 	p.running.Set(true)
diff --git a/voice/voicegateway/gateway.go b/voice/voicegateway/gateway.go
index 76dac4b..7be7fdb 100644
--- a/voice/voicegateway/gateway.go
+++ b/voice/voicegateway/gateway.go
@@ -181,13 +181,10 @@ func (c *Gateway) __start(ctx context.Context) error {
 		return errors.Wrap(err, "failed to wait for Ready or Resumed")
 	}
 
-	// Create an event loop executor.
-	c.EventLoop = wsutil.NewLoop(hello.HeartbeatInterval.Duration(), ch, c)
-
 	// Start the event handler, which also handles the pacemaker death signal.
 	c.waitGroup.Add(1)
 
-	c.EventLoop.RunAsync(func(err error) {
+	c.EventLoop.RunAsync(hello.HeartbeatInterval.Duration(), ch, c, func(err error) {
 		c.waitGroup.Done() // mark so Close() can exit.
 		wsutil.WSDebug("Event loop stopped.")