From e4fba8b04706ef4081aed9ff62667a0a8f306d87 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 8 Mar 2022 00:08:53 +0900
Subject: [PATCH] bug fix: compile error with Go 1.16 and older

---
 audio/internal/cbackend/player.go | 24 +++++++++++++++++++++---
 go.mod                            |  2 +-
 go.sum                            |  4 ++--
 internal/ui/context.go            | 18 +++++++++++-------
 4 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/audio/internal/cbackend/player.go b/audio/internal/cbackend/player.go
index b3152f1b5..0633acd09 100644
--- a/audio/internal/cbackend/player.go
+++ b/audio/internal/cbackend/player.go
@@ -24,7 +24,6 @@ import (
 	"io"
 	"runtime"
 	"sync"
-	"sync/atomic"
 )
 
 type playerState int
@@ -129,7 +128,7 @@ type playerImpl struct {
 	context *Context
 	src     io.Reader
 	volume  float64
-	err     atomic.Value
+	err     atomicError
 	state   playerState
 	tmpbuf  []byte
 	buf     []byte
@@ -395,6 +394,25 @@ func (p *playerImpl) readSourceToBuffer() {
 }
 
 func (p *playerImpl) setErrorImpl(err error) {
-	p.err.CompareAndSwap(nil, err)
+	p.err.TryStore(err)
 	p.closeImpl()
 }
+
+type atomicError struct {
+	err error
+	m   sync.Mutex
+}
+
+func (a *atomicError) TryStore(err error) {
+	a.m.Lock()
+	defer a.m.Unlock()
+	if a.err == nil {
+		a.err = err
+	}
+}
+
+func (a *atomicError) Load() error {
+	a.m.Lock()
+	defer a.m.Unlock()
+	return a.err
+}
diff --git a/go.mod b/go.mod
index bda039779..68fc4b81e 100644
--- a/go.mod
+++ b/go.mod
@@ -7,7 +7,7 @@ require (
 	github.com/hajimehoshi/bitmapfont/v2 v2.2.0
 	github.com/hajimehoshi/file2byteslice v0.0.0-20210813153925-5340248a8f41
 	github.com/hajimehoshi/go-mp3 v0.3.2
-	github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307144353-ebc14f63b1c1
+	github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307150401-d142925f4f40
 	github.com/jakecoffman/cp v1.1.0
 	github.com/jezek/xgb v0.0.0-20210312150743-0e0f116e1240
 	github.com/jfreymuth/oggvorbis v1.0.3
diff --git a/go.sum b/go.sum
index 4b009c1e8..a63a2d3ed 100644
--- a/go.sum
+++ b/go.sum
@@ -9,8 +9,8 @@ github.com/hajimehoshi/go-mp3 v0.3.2 h1:xSYNE2F3lxtOu9BRjCWHHceg7S91IHfXfXp5+LYQ
 github.com/hajimehoshi/go-mp3 v0.3.2/go.mod h1:qMJj/CSDxx6CGHiZeCgbiq2DSUkbK0UbtXShQcnfyMM=
 github.com/hajimehoshi/oto v0.6.1 h1:7cJz/zRQV4aJvMSSRqzN2TImoVVMpE0BCY4nrNJaDOM=
 github.com/hajimehoshi/oto v0.6.1/go.mod h1:0QXGEkbuJRohbJaxr7ZQSxnju7hEhseiPx2hrh6raOI=
-github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307144353-ebc14f63b1c1 h1:i3nUxJnazLDnglzCtwoNmqX88Nf5JmRbKzJeQ4gCsr4=
-github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307144353-ebc14f63b1c1/go.mod h1:rUKQmwMkqmRxe+IAof9+tuYA2ofm8cAWXFmSfzDN8vQ=
+github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307150401-d142925f4f40 h1:i1wPmufpfePzHxDJPiTX1tR2nvSVZ9JbUvKbTeVIzQ0=
+github.com/hajimehoshi/oto/v2 v2.1.0-alpha.7.0.20220307150401-d142925f4f40/go.mod h1:rUKQmwMkqmRxe+IAof9+tuYA2ofm8cAWXFmSfzDN8vQ=
 github.com/jakecoffman/cp v1.1.0 h1:bhKvCNbAddYegYHSV5abG3G23vZdsISgqXa4X/lK8Oo=
 github.com/jakecoffman/cp v1.1.0/go.mod h1:JjY/Fp6d8E1CHnu74gWNnU0+b9VzEdUVPoJxg2PsTQg=
 github.com/jezek/xgb v0.0.0-20210312150743-0e0f116e1240 h1:dy+DS31tGEGCsZzB45HmJJNHjur8GDgtRNX9U7HnSX4=
diff --git a/internal/ui/context.go b/internal/ui/context.go
index 4a7a311d3..1950f2fb3 100644
--- a/internal/ui/context.go
+++ b/internal/ui/context.go
@@ -174,7 +174,9 @@ var theGlobalState = globalState{
 // globalState represents a global state in this package.
 // This is available even before the game loop starts.
 type globalState struct {
-	err_                       atomic.Value
+	err_ error
+	errM sync.Mutex
+
 	fpsMode_                   int32
 	maxTPS_                    int32
 	isScreenClearedEveryFrame_ int32
@@ -182,15 +184,17 @@ type globalState struct {
 }
 
 func (g *globalState) error() error {
-	err, ok := g.err_.Load().(error)
-	if !ok {
-		return nil
-	}
-	return err
+	g.errM.Lock()
+	defer g.errM.Unlock()
+	return g.err_
 }
 
 func (g *globalState) setError(err error) {
-	g.err_.CompareAndSwap(nil, err)
+	g.errM.Lock()
+	defer g.errM.Unlock()
+	if g.err_ == nil {
+		g.err_ = err
+	}
 }
 
 func (g *globalState) fpsMode() FPSModeType {